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1

Porterfield named ASTM Fellow  

NLE Websites -- All DOE Office Websites (Extended Search)

in standards development. Achievements Porterfield serves on both the ASTM Nuclear Fuel Cycle International Committee and the ASTM Water International Committee. He has led or...

2

Glossary API Gravity: An  

Gasoline and Diesel Fuel Update (EIA)

5 60 60 131 5 . . The higher the API gravity, the lighter the compound. Light crudes generally exceed 38 degrees API and heavy crudes are commonly labeled as all crudes with an API gravity of 22 degrees or below. Intermediate crudes fall in the range of 22 degrees to 38 degrees API gravity. ASTM: American Society for Testing and Materials. Aviation Gasoline (Finished): A complex mixture of relatively volatile hydrocarbons with or without small quantities of additives, blended to form a fuel suitable for use in aviation reciprocating engines. Fuel specifi- cations are provided in ASTM Specification D 910 and Military Specification MIL-G-5572. Note: Data on blending components are not counted in data on fin- ished aviation gasoline. Barrel: A volumetric unit of measure for crude oil and petroleum products equivalent to 42 U.S. gallons. Bulk Sales: Wholesale sales of gasoline in individual

3

Glossary API Gravity: An  

Gasoline and Diesel Fuel Update (EIA)

60 60 1315 . . The higher the API gravity, the lighter the compound. Light crudes generally exceed 38 degrees API and heavy crudes are commonly labeled as all crudes with an API gravity of 22 degrees or below. Intermediate crudes fall in the range of 22 degrees to 38 degrees API gravity. ASTM: American Society for Testing and Materials. Aviation Gasoline (Finished): A complex mixture of relatively volatile hydrocarbons with or without small quantities of additives, blended to form a fuel suitable for use in aviation reciprocating engines. Fuel specifi- cations are provided in ASTM Specification D 910 and Military Specification MIL-G-5572. Note: Data on blending components are not counted in data on fin- ished aviation gasoline. Barrel: A volumetric unit of measure for crude oil and petroleum products equivalent to 42 U.S. gallons. Bulk Sales: Wholesale sales of gasoline in individual

4

Insulation Materials: Testing and Applications, Third Volume, ASTM STP 1320, R. S. Graves and R. R. Zarr, Eds., American Society for Testing and Materials, 1997.  

E-Print Network (OSTI)

LBNL-38925 TA-399 Insulation Materials: Testing and Applications, Third Volume, ASTM STP 1320, R. S by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Building Technology, State, and Dariush K. Arasteh Windows and Daylighting Group Building Technologies Department Environmental Energy

5

Alternative Fuels Data Center: ASTM Biodiesel Specifications  

Alternative Fuels and Advanced Vehicles Data Center (EERE)

ASTM Biodiesel ASTM Biodiesel Specifications to someone by E-mail Share Alternative Fuels Data Center: ASTM Biodiesel Specifications on Facebook Tweet about Alternative Fuels Data Center: ASTM Biodiesel Specifications on Twitter Bookmark Alternative Fuels Data Center: ASTM Biodiesel Specifications on Google Bookmark Alternative Fuels Data Center: ASTM Biodiesel Specifications on Delicious Rank Alternative Fuels Data Center: ASTM Biodiesel Specifications on Digg Find More places to share Alternative Fuels Data Center: ASTM Biodiesel Specifications on AddThis.com... More in this section... Biodiesel Basics Blends Production & Distribution Specifications Related Links Benefits & Considerations Stations Vehicles Laws & Incentives ASTM Biodiesel Specifications These tables show selected ASTM requirements for B100 and B6 to B20. Note

6

GF5 / ROBO Test or ASTM Sequence IIIGA Test, ASTM D7528 Aged Oil LowTemperature Viscosity  

E-Print Network (OSTI)

GF5 / ROBO Test or ASTM Sequence IIIGA Test, ASTM D7528 Aged Oil LowTemperature Viscosity SPECIFICATIONS PROCEDURE PARAMETERS The ROBO test is a proposed test for performance category GF.5, ASTM D7528. The ASTM Sequence IIIGA Test, ASTM D7320 may be run instead of the above. A total

Chapman, Clark R.

7

Massive Gravity  

E-Print Network (OSTI)

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, 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 alternative and related models of massive gravity such as new massive gravity, Lorentz-violating massive gravity and non-local massive gravity.

de Rham, Claudia

2014-01-01T23:59:59.000Z

8

Massive Gravity  

E-Print Network (OSTI)

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, 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 alternative and related models of massive gravity such as new massive gravity, Lorentz-violating massive gravity and non-local massive gravity.

Claudia de Rham

2014-01-16T23:59:59.000Z

9

Ball Rust Test(ASTM D 6557) FIELD SERVICE SIMULATED  

E-Print Network (OSTI)

-controlled shaker table. A syringe pump is used to inject acid into the test oil. In addition, a compressed air the Sequence IID (ASTM D 5844) gaso- line engine test, and evaluates the ability of an oil to prevent with regard to rusting. TEST PARAMETERS Tests are run for 18 hours with the test oil environment controlled

Chapman, Clark R.

10

NIST, ASTM Land a One-Two Punch to Fight Explosives ...  

Science Conference Proceedings (OSTI)

NIST, ASTM Land a One-Two Punch to Fight Explosives Terrorism. From NIST Tech Beat: March 30, 2011. ...

2012-11-26T23:59:59.000Z

11

Massive gravity from bimetric gravity  

E-Print Network (OSTI)

We discuss the subtle relationship between so-called massive gravity (that is, gravity incorporating a non-zero graviton mass) and bimetric gravity, focussing 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, and in particular, in a cosmological context can lead to an interesting interplay between the "background" and "foreground" metrics. The fact that in bimetric theories one always has two sets of metric equations of motion, one for each metric, continues to have an effect even in the massive gravity limit. Thus, 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.

Baccetti, Valentina; Visser, Matt

2012-01-01T23:59:59.000Z

12

Liouville gravity from Einstein gravity  

E-Print Network (OSTI)

We show that Liouville gravity arises as the limit of pure Einstein gravity in 2+epsilon dimensions as epsilon goes to zero, provided Newton's constant scales with epsilon. Our procedure - spherical reduction, dualization, limit, dualizing back - passes several consistency tests: geometric properties, interactions with matter and the Bekenstein-Hawking entropy are as expected from Einstein gravity.

D. Grumiller; R. Jackiw

2007-12-21T23:59:59.000Z

13

Einstein Gravity from Conformal Gravity  

E-Print Network (OSTI)

We show that that four dimensional conformal gravity plus a simple Neumann boundary condition can be used to get the semiclassical (or tree level) wavefunction of the universe of four dimensional asymptotically de-Sitter or Euclidean anti-de Sitter spacetimes. This simple Neumann boundary condition selects the Einstein solution out of the more numerous solutions of conformal gravity. It thus removes the ghosts of conformal gravity from this computation. In the case of a five dimensional pure gravity theory with a positive cosmological constant we show that the late time superhorizon tree level probability measure, $|\\Psi [ g ]|^2$, for its four dimensional spatial slices is given by the action of Euclidean four dimensional conformal gravity.

Juan Maldacena

2011-05-27T23:59:59.000Z

14

Overview of ASTM D03 Involvement with Hydrogen Fuel Purity Specificati...  

NLE Websites -- All DOE Office Websites (Extended Search)

Breath of H2 Standardization Other ASTM Committees: * Committee D05 on Coal and Coke * Committee D14 on Adhesives * Committee D16 on Aromatic Hydrocarbons and Related...

15

Rocket-borne, low gravity cryogenic heat transfer experiment  

SciTech Connect

From AIAA/NSA/ASTM/IES 7th space simulation conference; Los Angeles, Calif11nia, USA (12 Nov 1973). In order to obtain steady state data on nucleate boiling heat transfer to liquid helium in a nearly zero gravity environment a rocket-borne experiment was designed, built and successfully flown. A description of the apparatus and flight is presented along with preliminary results. (auth)

Williamson, K.D. Jr.; Edeskuty, F.J.; Taylor, J.F.

1974-04-30T23:59:59.000Z

16

Gravity brake  

DOE Patents (OSTI)

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.

Lujan, Richard E. (Santa Fe, NM)

2001-01-01T23:59:59.000Z

17

Gravity settling  

DOE Patents (OSTI)

Solids are separated from a liquid in a gravity settler provided with inclined solid intercepting surfaces to intercept the solid settling path to coalesce the solids and increase the settling rate. The intercepting surfaces are inverted V-shaped plates, each formed from first and second downwardly inclined upwardly curved intersecting conical sections having their apices at the vessel wall.

Davis, Hyman R. (Glenridge, NJ); Long, R. H. (Morristown, NJ); Simone, A. A. (Dover, NJ)

1979-01-01T23:59:59.000Z

18

Understanding gravity  

E-Print Network (OSTI)

AdS/CFT correspondence provides a holographic duality between gravitational physics and gauge dynamics. What field theory configurations lend themselves to a good semi-classical description? Relevance: Making precise the nature of the holographic map Understanding the emergence of geometry. What are “legal ” singularities in gravity (cosmic censorship)? Insight into new solutions. Motivation Conformal fluids Bulk geometry Horizons & entropy Conclusion

Mukund Rangamani

2008-01-01T23:59:59.000Z

19

Is nonrelativistic gravity possible?  

SciTech Connect

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.

Kocharyan, A. A. [School of Mathematical Sciences, Monash University, Clayton 3800 (Australia)

2009-07-15T23:59:59.000Z

20

Guide to ASTM test methods for the analysis of coal and coke  

Science Conference Proceedings (OSTI)

The guide includes brief descriptions of all 56 ASTM test methods that cover the physical, chemical, and spectroscopic analytical techniques to qualitatively and quantitatively identify over 40 chemical and physical properties of coal, coke, their products, and by-products.

R.A. Kishore Nadkarni (ed.)

2008-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "gravity astm american" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Intrusive gravity currents  

E-Print Network (OSTI)

The front speed of intrusive gravity currents. J. FluidP.F. Linden. Intrusive gravity currents. J. Fluid Mechanics,of mesoscale variability of gravity waves. Part II: Frontal,

Hang, Alice Thanh

2009-01-01T23:59:59.000Z

22

TORSION AND QUANTUM GRAVITY  

E-Print Network (OSTI)

more restrictive context of Einstein's theory of gravity.6782 TORSION AND QUANTUM GRAVITY Andrevr J, Him son Lawrencetorsion in conventional gravity cou~d in fact be dynamicaL A

Hanson, Andrew J.

2011-01-01T23:59:59.000Z

23

Newtonian gravity in loop quantum gravity  

E-Print Network (OSTI)

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.

Smolin, Lee

2010-01-01T23:59:59.000Z

24

Impact of Gravity Waves on Marine Stratocumulus Variability  

Science Conference Proceedings (OSTI)

The impact of gravity waves on marine stratocumulus is investigated using a large-eddy simulation model initialized with sounding profiles composited from the Variability of American Monsoon Systems (VAMOS) Ocean–Cloud–Atmosphere–Land Study ...

Qingfang Jiang; Shouping Wang

2012-12-01T23:59:59.000Z

25

Chiral gravity, log gravity, and extremal CFT  

Science Conference Proceedings (OSTI)

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

Maloney, Alexander [Physics Department, McGill University, Montreal, QC H3A 2T8 (Canada); Song Wei [Key Laboratory of Frontiers in Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing, 100190 (China); Center for the Fundamental Laws of Nature Jefferson Physical Laboratory, Harvard University, Cambridge, Massachusetts 02138 (United States); Strominger, Andrew [Center for the Fundamental Laws of Nature Jefferson Physical Laboratory, Harvard University, Cambridge, Massachusetts 02138 (United States)

2010-03-15T23:59:59.000Z

26

Chiral Gravity, Log Gravity and Extremal CFT  

E-Print Network (OSTI)

We show that the linearization of all exact solutions of classical chiral gravity around the AdS3 vacuum have positive energy. Non-chiral 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 CFT. Moreover we show that log gravity contains chiral gravity within it as a decoupled charge superselection sector. We normally 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.

Alexander Maloney; Wei Song; Andrew Strominger

2009-03-26T23:59:59.000Z

27

Towards noncommutative gravity  

E-Print Network (OSTI)

In this short article accessible for non-experts I discuss possible ways of constructing a non-commutative gravity paying special attention to possibilities of realizing the full diffeomorphism symmetry and to relations with 2D gravities.

D. V. Vassilevich

2009-02-04T23:59:59.000Z

28

Heigth and Gravity  

NLE Websites -- All DOE Office Websites (Extended Search)

Heigth and Gravity Name: Evan Location: NA Country: NA Date: NA Question: Does gravity effect a person's height? How does it? Would people with back problems benefit from time...

29

Motion in Quantum Gravity  

E-Print Network (OSTI)

We tackle the question of motion in Quantum Gravity: what does motion mean at the Planck scale? Although we are still far from a complete answer we consider here a toy model in which the problem can be formulated and resolved precisely. The setting of the toy model is three dimensional Euclidean gravity. Before studying the model in detail, we argue that Loop Quantum Gravity may provide a very useful approach when discussing the question of motion in Quantum Gravity.

Karim Noui

2010-03-31T23:59:59.000Z

30

Stephen Hawking Quantum Gravity  

E-Print Network (OSTI)

Stephen Hawking and Quantum Gravity Matt Visser Physics Department Washington University Saint Louis USA Science Saturdays 4 Nov 2000 #12; Stephen Hawking and Quantum Gravity Abstract: Through research, Stephen Hawking has captured a place in the popular imagina- tion. Quantum gravity in its various

Visser, Matt

31

Quantum Physics Einstein's Gravity  

E-Print Network (OSTI)

Quantum Physics confronts Einstein's Gravity Matt Visser Physics Department Washington University Saint Louis USA Science Saturdays 13 October 2001 #12; Quantum Physics confronts Einstein's Gravity and with Einstein's theory of gravity (the general relativity) is still the single biggest theoretical problem

Visser, Matt

32

Ultraviolet Complete Quantum Gravity  

E-Print Network (OSTI)

An ultraviolet complete (UV) quantum gravity theory is formulated in which vertex functions in Feynman graphs are entire functions and the propagating gravitons are described by local, causal propagators. A scalar-tensor action describes classical gravity theory. The cosmological constant problem is investigated in the context of the UV complete quantum gravity.

Moffat, J W

2010-01-01T23:59:59.000Z

33

The Universe Adventure - Gravity  

NLE Websites -- All DOE Office Websites (Extended Search)

Gravity: The Main Attraction Gravity: The Main Attraction Gravity Acts on All Matter Gravity's effect is apparent even at the largest scales: just as gravity keeps the Earth orbiting the sun, it holds these two irregular galaxies M32 and M110 in orbit around the larger Andromeda galaxy. In the late 1600s, the English mathematician Sir Isaac Newton gave the first scientific description of gravitation. Gravity is an attractive force existing between any two objects that have mass, causing them to accelerate towards each other. It is the weakest of the four fundamental forces but can act over great distances and is responsible for the formation of planets, stars, galaxies, and even larger scale structures such as groups and superclusters. Gravity is also the force that governs the motion of

34

Quantization of Emergent Gravity  

E-Print Network (OSTI)

Emergent gravity is based on a novel form of the equivalence principle known as the Darboux theorem or the Moser lemma in symplectic geometry stating that the electromagnetic force can always be eliminated by a local coordinate transformation as far as spacetime admits a symplectic structure, in other words, a microscopic spacetime becomes noncommutative (NC). If gravity emerges from U(1) gauge theory on NC spacetime, this picture of emergent gravity suggests a completely new quantization scheme where quantum gravity is defined by quantizing spacetime itself, leading to a dynamical NC spacetime. Therefore the quantization of emergent gravity is radically different from the conventional approach trying to quantize a phase space of metric fields. This approach for quantum gravity allows a background independent formulation where spacetime as well as matter fields is equally emergent from a universal vacuum of quantum gravity.

Hyun Seok Yang

2013-12-02T23:59:59.000Z

35

Category:Gravity Techniques | Open Energy Information  

Open Energy Info (EERE)

Techniques page? For detailed information on Gravity Techniques, click here. Category:Gravity Techniques Add.png Add a new Gravity Techniques Technique Pages in category "Gravity...

36

Lectures on loop gravity  

E-Print Network (OSTI)

This is the first version of the introductory lectures on loop quantum gravity that I will give at the quantum gravity school in Zakopane. The theory is presented in self-contained form, without emphasis on its derivation from classical general relativity. Dynamics is given in the covariant form. The approximations needed to compute physical quantities are discussed. Some applications are described, including the recent derivation of de Sitter cosmology from full quantum gravity.

Rovelli, Carlo

2011-01-01T23:59:59.000Z

37

Dark gravity and cosmology  

E-Print Network (OSTI)

The previous version of this article was a first attempt to confront the Dark Gravity theory to cosmological data. However, more recent developments lead to the conclusion that the cosmological principle is probably not valid in Dark Gravity so that this kind of analysis is at best very premature. A more recent and living review of the Dark Gravity theory can be found in gr-qc/0610079

F. Henry-Couannier; A. Tilquin; C. Tao; A. Ealet

2005-09-05T23:59:59.000Z

38

Is Gravity an Interaction?  

E-Print Network (OSTI)

We consider a possibility that gravity is not an interaction but a manifestation of a symmetry based on a Galois field.

Felix M. Lev

2009-05-06T23:59:59.000Z

39

Gold Standard Gravity ?†  

E-Print Network (OSTI)

This paper provides striking confirmation of the restrictions of the structural gravity model of trade. Structural forces predicted by theory explain 95 % of the variation of the fixed effects used to control for them in the recent gravity literature, fixed effects that in principle could reflect other forces. This validation opens avenues to inferring unobserved sectoral activity and multilateral resistance variables by equating fixed effects with structural gravity counterparts. Our findings also provide important validation of a host of general equilibrium comparative static exercises based on the structural gravity model.

James E. Anderson; Yoto V. Yotov; Dave Donaldson; Keith Head; Michael Waugh; We Arthur Lewbel

2012-01-01T23:59:59.000Z

40

Quantum gravity on the lattice  

E-Print Network (OSTI)

the Conference Quantum Gravity: Challenges and Perspectives.divergences in quantum gravity. In: Hawking, S.W. , Israel,f ) V n?1 ( f ) = Quantum gravity on the lattice Similarly,

Hamber, Herbert W.

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gravity astm american" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Particle Dynamics And Emergent Gravity  

E-Print Network (OSTI)

The emergent gravity proposal is examined within the framework of noncommutative QED/gravity correspondence from particle dynamics point of view.

Amir H. Fatollahi

2008-05-08T23:59:59.000Z

42

ASTM STANDARD GUIDE FOR EVALUATING DISPOSAL OPTIONS FOR REUSE OF CONCRETE FROM NUCLEAR FACILITY DECOMMISSIONING  

SciTech Connect

Within the nuclear industry, many contaminated facilities that require decommissioning contain huge volumes of concrete. This concrete is generally disposed of as low-level waste at a high cost. Much of the concrete is lightly contaminated and could be reused as roadbed, fill material, or aggregate for new concrete, thus saving millions of dollars. However, because of the possibility of volumetric contamination and the lack of a method to evaluate the risks and costs of reusing concrete, reuse is rarely considered. To address this problem, Argonne National Laboratory-East (ANL-E) and the Idaho National Engineering and Environmental Laboratory teamed to write a ''concrete protocol'' to help evaluate the ramifications of reusing concrete within the U.S. Department of Energy (DOE). This document, titled the Protocol for Development of Authorized Release Limits for Concrete at U.S. Department of Energy Site (1) is based on ANL-E's previously developed scrap metal recycle protocols; on the 10-step method outlined in DOE's draft handbook, Controlling Release for Reuse or Recycle of Property Containing Residual Radioactive Material (2); and on DOE Order 4500.5, Radiation Protection of the Public and the Environment (3). The DOE concrete protocol was the basis for the ASTM Standard Guide for Evaluating Disposal Options for Concrete from Nuclear Facility Decommissioning, which was written to make the information available to a wider audience outside DOE. The resulting ASTM Standard Guide is a more concise version that can be used by the nuclear industry worldwide to evaluate the risks and costs of reusing concrete from nuclear facility decommissioning. The bulk of the ASTM Standard Guide focuses on evaluating the dose and cost for each disposal option. The user calculates these from the detailed formulas and tabulated data provided, then compares the dose and cost for each disposal option to select the best option that meets regulatory requirements. With this information, the reuse of concrete may be possible, thus reducing dose and decontamination and decommissioning costs. This paper outlines ten steps required to release concrete for reuse and discusses the disposal options covered in the ASTM Standard Guide.

Phillips, Ann Marie; Meservey, Richard H.

2003-02-27T23:59:59.000Z

43

Gauge/Gravity Duality (Gauge Gravity Duality)  

SciTech Connect

Gauge theories, which describe the particle interactions, are well understood, while quantum gravity leads to many puzzles. Remarkably, in recent years we have learned that these are actually dual, the same system written in different variables. On the one hand, this provides our most precise description of quantum gravity, resolves some long-standing paradoxes, and points to new principles. On the other, it gives a new perspective on strong interactions, with surprising connections to other areas of physics. I describe these ideas, and discuss current and future directions.

Polchinski, Joseph (Kavli Institute for Theoretical Physics)

2010-02-24T23:59:59.000Z

44

Probability around the Quantum Gravity. Part 1: Planar Pure Gravity  

E-Print Network (OSTI)

Probability around the Quantum Gravity. Part 1: Planar Pure Gravity V.A.Malyshev \\Lambda September 17, 1998 Abstract In this paper we study stochastic dynamics which leaves quantum gravity equilibrium science and biology. At the same time the paper can serve an intro­ duction to quantum gravity

45

Properties of concrete incorporating high volumes of ASTM Class F fly ash  

E-Print Network (OSTI)

This thesis presents the results of research performed in developing high-volume fly ash (HVFA) concrete incorporating ASTM Type I cement and ASTM Class F fly ash from Big Brown Power Plant of TU Electric, Texas. In HVFA concrete, the proportion of fly ash was 58 percent by weight of the total cementitious materials, the water and cement content were kept low at 115 and 155 k g/M3 , respectively. A broad range of engineering properties was investigated including compressive strength, flexural strength, splitting-tensile strength, Young's modulus of elasticity, drying shrinkage, resistance to freeze-thaw cycling, pore structure and activation energy. A preliminary economic analysis was also performed on HVFA concrete. The HVFA concrete evaluated in this study had satisfactory workability and setting characteristics. It also exhibited excellent mechanical properties with satisfactory early age strength and good long-term strength development. The HVFA concrete had relatively low drying shrinkage and a very fine pore system. Excellent durability under freeze-thaw cycling was also found for the air-entrained HVFA concrete. Results from activation energy test show that strength gain of the HVFA concrete under isothermal curing conditions could be modeled appropriately using Plowman's logarithmic strength-age model. The relative strength-maturity relationship was established for the HVFA concrete containing various percentages of additional gypsum. The HVFA concrete investigated was determined to be cost effective. It was shown that about two and half dollars per cubic meter could be saved through savings on portland cement.

Li, Wei Tung

1995-01-01T23:59:59.000Z

46

Na and Li ion diffusion in modified ASTM C 1260 test by Magnetic Resonance Imaging (MRI)  

SciTech Connect

In the current study, MRI was applied to investigate lithium and sodium ion diffusion in cement paste and mortars containing inert sand and borosilicate glass. Paste and mortars were treated by complying with ASTM C 1260. Lithium and sodium distribution profiles were collected at different ages after different treatments. Results revealed that sodium ions had a greater diffusion rate than lithium ions, suggesting that Na reaches the aggregate particle surface before Li. Results also showed that Na and Li ions had a competitive diffusion process in mortars; soaking in a solution with higher [Li] favored Li diffusion but hindered Na diffusion. In mortars containing glass, a substantial amount of Li was consumed by the formation of ASR products. When [Li] in soaking solution was reduced to 0.37 N, a distinctive Na distribution profile was observed, indicating the free-state Na ions were continuously transformed to solid reaction products by ASR. Hence, in the modified ASTM C 1260 test, [Li] in the storage solution should be controlled at 0.74 N, in order to completely prevent the consumption of Na ions and thus stop ASR.

Feng, X. [Department of Civil Engineering, University of New Brunswick, Fredericton, NB (Canada)], E-mail: XFeng@ctlgroup.com; Balcom, B.J. [MRI Center, Department of Physics, University of New Brunswick, Fredericton, NB (Canada); Thomas, M.D.A.; Bremner, T.W. [Department of Civil Engineering, University of New Brunswick, Fredericton, NB (Canada)

2008-12-15T23:59:59.000Z

47

Gravity in Gauge Mediation  

E-Print Network (OSTI)

We investigate O'Raifeartaigh-type models for F-term supersymmetry breaking in gauge mediation scenarios in the presence of gravity. It is pointed out that the vacuum structure of those models is such that in metastable vacua gravity mediation contribution to scalar masses is always suppressed to the level below 1 percent, almost sufficient for avoiding FCNC problem. Close to that limit, gravitino mass can be in the range 10-100 GeV, opening several interesting possibilities for gauge mediation models, including Giudice-Masiero mechanism for mu and Bmu generation. Gravity sector can include stabilized moduli.

Zygmunt Lalak; Stefan Pokorski; Krzysztof Turzynski

2008-08-04T23:59:59.000Z

48

Quantum Gravity An introductory survey  

E-Print Network (OSTI)

Quantum Gravity An introductory survey Hermann Nicolai Max-Planck-Institut f¨ur Gravitationsphysik (Albert­Einstein­Institut, Potsdam) . ­ p.1/25 #12;Why Quantum Gravity? . ­ p.2/25 #12;Why Quantum Gravity theories: . ­ p.2/25 #12;Why Quantum Gravity? General Relativity and Quantum Theory: not only very

Rossak, Wilhelm R.

49

Toroidal solutions in Horava Gravity  

E-Print Network (OSTI)

Recently a new four-dimensional non relativistic renormalizable theory of gravity was proposed by Horava. This gravity reduces to Einstein gravity at large distances. In this paper by using the new action for gravity we present different toroidal solutions to the equations of motion. Our solutions describe the near horizon geometry with slow rotating parameter.

Ahmad Ghodsi

2009-05-06T23:59:59.000Z

50

Equivalence between therm and gravity  

E-Print Network (OSTI)

We introduce the notion of thermal entropy density, and first demonstrated that there exists an equivalence between therm and gravity without depending on the definition of temperature or horizon. This equivalence indicates that gravity possesses thermal features, or, therm possesses effects of gravity. This may shed light on the nature of gravity.

Yang, Rong-Jia

2011-01-01T23:59:59.000Z

51

Gravity and the quantum potential  

E-Print Network (OSTI)

We review some material connecting gravity and the quantum potential and provide a few new observations.

Robert Carroll

2004-06-02T23:59:59.000Z

52

Gravity Waves from Thunderstorms  

Science Conference Proceedings (OSTI)

Gravity waves generated by severe thunderstorms in the eastern Ohio-Pennsylvania area were recorded by an array of microbarovariographs at Palisades, New York and by standard microbarographs across northeastern United States. The waves were ...

Nambath K. Balachandran

1980-06-01T23:59:59.000Z

53

Why gravity is fundamental  

E-Print Network (OSTI)

It is argued that the existence of a minimum size of spacetime may imply the fundamental existence of gravity as a geometric property of spacetime described by general relativity.

Shan Gao

2010-01-18T23:59:59.000Z

54

Causal Newton Gravity Law  

E-Print Network (OSTI)

The equations of the relativistic causal Newton gravity law for the planets of the solar system are studied in the approximation when the Sun rests at the coordinates origin and the planets do not iteract between each other.

Yury M. Zinoviev

2012-01-17T23:59:59.000Z

55

Exercise in artificial gravity  

E-Print Network (OSTI)

Artificial gravity provided by short radius centrifugation is considered a promising countermeasure to the deleterious physiological effects of microgravity during long-duration space flight. We investigated the feasibility ...

Edmonds, Jessica Leigh

2005-01-01T23:59:59.000Z

56

Dog Center of Gravity  

NLE Websites -- All DOE Office Websites (Extended Search)

Dog Center of Gravity Name: Dania Status: Student Grade: 9-12 Location: AZ Country: USA Date: NA Question: Currently in physics we are working with projectile motion. I am...

57

Why gravity is fundamental  

E-Print Network (OSTI)

It is argued that the existence of a minimum size of spacetime may imply the fundamental existence of gravity as a geometric property of spacetime described by general relativity.

Gao, Sheldon

2010-01-01T23:59:59.000Z

58

Gravity-driven intrusions in stratified fluids  

E-Print Network (OSTI)

5.5.1 Five interleaving interfacial gravity currents 5.5.2Ten interleaving interfacial gravity currents . 5.6partial- depth intrusive gravity currents,” Atmosphere -

Maurer, Benjamin Dudley

2011-01-01T23:59:59.000Z

59

Exploring Gravity and Gravitational Wave Dynamics Part II: Gravity Models  

Science Conference Proceedings (OSTI)

The need for a new gravity model may explain anomalous behavior exhibited by several recent experiments described in Part I. Although Newtonian gravity is adequate for predicting the motion of celestial bodies

P. A. Murad

2007-01-01T23:59:59.000Z

60

On the no-gravity limit of gravity  

E-Print Network (OSTI)

We argue that Relative Locality may arise in the no gravity $G\\rightarrow0$ limit of gravity. In this limit gravity becomes a topological field theory of the BF type that, after coupling to particles, may effectively deform its dynamics. We briefly discuss another no gravity limit with a self dual ground state as well as the topological ultra strong $G\\rightarrow\\infty$ one.

Kowalski-Glikman, J

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gravity astm american" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Macroscopic quantization of gravity  

E-Print Network (OSTI)

The moon is receding from earth at an average rate of 3.8 cm/yr [6][7][9][12].This anomaly cannot be attributed to the well-known tidal exchange of angular momentum between earth and moon [8]. A secular change in the astronomical unit AU is definitely a concern, it is reportedly increasing by about 15 cm/yr [9][10], in this letter; the concept of macroscopic quantization of gravity is introduced to account for these anomalies on theoretical basis. Interestingly, it was found useful in measuring the speed of gravity! What is more interesting is the fact that this concept is based on solid well known classical physics with no modifications to any standard model. It was found that the speed of gravity cg is in the range 10^4 c < cg < 10^5 c.

M. Y. Amin

2009-12-12T23:59:59.000Z

62

Euler Chern Simons Gravity from Lovelock Born Infeld Gravity  

E-Print Network (OSTI)

In the context of a gauge theoretical formulation, higher dimensional gravity invariant under the AdS group is dimensionally reduced to Euler-Chern-Simons gravity. The dimensional reduction procedure of Grignani-Nardelli [Phys. Lett. B 300, 38 (1993)] is generalized so as to permit reducing D-dimensional Lanczos Lovelock gravity to d=D-1 dimensions.

Fernando Izaurieta; Eduardo Rodriguez; Patricio Salgado

2004-02-25T23:59:59.000Z

63

Gravity wraps Higgs boson  

E-Print Network (OSTI)

It is shown that, by rescaling the matter fields and metric tensor with appropriate powers of the Higgs field, the Higgs boson can be wholly transferred from material sector to the gravity sector in which it possesses only gravitational interactions and escapes detection in collider experiments. The Higgs boson gets buried in a scalar-tensor theory of gravity wherein it might be of relevance for Dark Energy. It is absent from the electroweak spectrum yet leptons, quarks and vector bosons possess their already known properties. The Higgs boson can contact with the matter sector via only the higher-dimensional operators suppressed by a cutoff scale.

Demir, Durmus A

2011-01-01T23:59:59.000Z

64

Sodium Nightglow and Gravity Waves  

Science Conference Proceedings (OSTI)

Oscillations in intensity of NaD nightglow attributed to mesospheric gravity waves have bean studied. Fractional atmospheric density perturbations have been obtained by means of the linear gravity waves theory of Hines. Values of other parameters ...

A. Molina

1983-10-01T23:59:59.000Z

65

Quantum gravity on the lattice  

E-Print Network (OSTI)

C. : Fields on a random lattice. In: Progress in Gauge Field= Quantum gravity on the lattice Similarly, one can considerQuantum gravity on the lattice Herbert W. Hamber Received:

Hamber, Herbert W.

2009-01-01T23:59:59.000Z

66

Introduction to Loop Quantum Gravity  

E-Print Network (OSTI)

The questions I have been asked during the 5th International School on Field Theory and Gravitation, have compelled me to give an account of the premises that I consider important for a beginner's approach to Loop Quantum Gravity. After a description of some general arguments and an introduction to the canonical theory of gravity, I review the background independent approach to quantum gravity, giving only a brief survey of Loop Quantum Gravity.

Mercuri, Simone

2010-01-01T23:59:59.000Z

67

Gravity's weight on worldline fuzziness  

E-Print Network (OSTI)

We investigate a connection between recent results in 3D quantum gravity, providing an effective noncommutative-spacetime description, and some earlier heuristic descriptions of a quantum-gravity contribution to the fuzziness of the worldlines of particles. We show that 3D-gravity-inspired spacetime noncommutativity reflects some of the features suggested by previous heuristic arguments. Most notably, gravity-induced worldline fuzziness, while irrelevantly small on terrestrial scales, could be observably large for propagation of particles over cosmological distances.

Amelino-Camelia, Giovanni; Rosati, Giacomo

2012-01-01T23:59:59.000Z

68

Introduction to Loop Quantum Gravity  

E-Print Network (OSTI)

The questions I have been asked during the 5th International School on Field Theory and Gravitation, have compelled me to give an account of the premises that I consider important for a beginner's approach to Loop Quantum Gravity. After a description of some general arguments and an introduction to the canonical theory of gravity, I review the background independent approach to quantum gravity, giving only a brief survey of Loop Quantum Gravity.

Simone Mercuri

2010-01-08T23:59:59.000Z

69

Massive gravity on a brane  

E-Print Network (OSTI)

Dam, Veltman and Zakharov [13], implies that the tensor structure of the gravitational interaction deviates from that of Einstein gravity.

Chacko, Z.; Graesser, M.L.; Grojean, C.; Pilo, L.

2003-01-01T23:59:59.000Z

70

New probe of modified gravity  

E-Print Network (OSTI)

We suggest a new efficient way to constrain a certain class of large scale modifications of gravity. We show that the scale-free relation between density and size of Dark Matter halos, predicted within the LambdaCDM model with Newtonian gravity, gets modified in a wide class of theories of modified gravity.

Boyarsky, Alexey

2010-01-01T23:59:59.000Z

71

D-Dimensional Log Gravity  

E-Print Network (OSTI)

We study Einstein gravity in dimensions $D\\geq 4$ modified by curvature squared at critical point where the theory contains only massless gravitons. We show that at the critical point a new mode appears leading to a logarithmic gravity in the theory. The corresponding logarithmic solution may provide a gravity description of logarithmic CFT in higher dimensions.

Alishahiha, Mohsen

2011-01-01T23:59:59.000Z

72

5, 1102911054, 2005 Convective gravity  

E-Print Network (OSTI)

ACPD 5, 11029­11054, 2005 Convective gravity waves at mid-latitudes Y. G. Choi et al. Title Page Discussions Wind-profiler observations of gravity waves produced by convection at mid-latitudes Y. G. Choi1­11054, 2005 Convective gravity waves at mid-latitudes Y. G. Choi et al. Title Page Abstract Introduction

Paris-Sud XI, Université de

73

CFT, Integrable Models Liouville Gravity  

E-Print Network (OSTI)

CFT, Integrable Models And Liouville Gravity Chernogolovka 2009 Sunday June 28, 2009. Conference as one of components of their L, A pairs. #12;CFT, Integrable Models And Liouville Gravity Chernogolovka Gravity Chernogolovka, 2009 Tuesday June 30, 2009. CONFERENCE HALL 09:30­10:10 Herman Boos (Wuppertal

Fominov, Yakov

74

From Classical To Quantum Gravity: Introduction to Loop Quantum Gravity  

E-Print Network (OSTI)

We present an introduction to the canonical quantization of gravity performed in loop quantum gravity, based on lectures held at the 3rd quantum geometry and quantum gravity school in Zakopane in 2011. A special feature of this introduction is the inclusion of new proposals for coupling matter to gravity that can be used to deparametrize the theory, thus making its dynamics more tractable. The classical and quantum aspects of these new proposals are explained alongside the standard quantization of vacuum general relativity in loop quantum gravity.

Giesel, Kristina

2012-01-01T23:59:59.000Z

75

Even-dimensional topological gravity from Chern-Simons gravity  

E-Print Network (OSTI)

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 $\\phi^{a}$, 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).

Nelson Merino; Alfredo Perez; Patricio Salgado

2009-10-08T23:59:59.000Z

76

Bigravity and Massive Gravity  

Science Conference Proceedings (OSTI)

We discuss some issues concerning the global structure of spherically symmetric solutions of bigravity. We propose maximal extensions of manifolds where two causal structure coexist. Besides we make some comments about the perturbations of these solutions and their relation to massive gravity and the cosmological constant problem.

D. Blas

2006-01-01T23:59:59.000Z

77

Isometrodynamics and Gravity  

E-Print Network (OSTI)

Isometrodynamics (ID), the gauge theory of the group of volume-preserving diffeomorphisms of an "inner" D-dimensional flat space, is tentatively interpreted as a fundamental theory of gravity. Dimensional analysis shows that the Planck length l_P - and through it \\hbar and \\Gamma - enters the gauge field action linking ID and gravity in a natural way. Noting that the ID gauge field couples solely through derivatives acting on "inner" space variables all ID fields are Taylor-expanded in "inner" space. Integrating out the "inner" space variables yields an effective field theory for the coefficient fields with l_P^2 emerging as the expansion parameter. For \\hbar goint to zero only the leading order field does not vanish. This classical field couples to the matter Noether currents and charges related to the translation invariance in "inner" space. A model coupling this leading order field to a matter point source is established and solved. Interpreting the matter Noether charge in terms of gravitational mass Newton's inverse square law is finally derived for a static gauge field source and a slowly moving test particle. Gravity emerges as potentially related to field variations over "inner" space and might microscopically be described by the ID gauge field or equivalently by an infinite string of coefficient fields only the leading term of which is related to the macroscopical effects of gravity.

Christian Wiesendanger

2009-06-23T23:59:59.000Z

78

Quantum Gravity and Turbulence  

E-Print Network (OSTI)

We apply recent advances in quantum gravity to the problem of turbulence. Adopting the AdS/CFT approach we propose a string theory of turbulence that explains the Kolmogorov scaling in 3+1 dimensions and the Kraichnan and Kolmogorov scalings in 2+1 dimensions. In the gravitational context, turbulence is intimately related to the properties of spacetime, or quantum, foam.

Vishnu Jejjala; Djordje Minic; Y. Jack Ng; Chia-Hsiung Tze

2010-05-18T23:59:59.000Z

79

The gravity of light  

E-Print Network (OSTI)

A solution of the old problem raised by Tolman, Ehrenfest, Podolsky and Wheeler, concerning the lack of attraction of two light pencils "moving parallel", is proposed, considering that the light can be source of nonlinear gravitational waves corresponding (in the would be quantum theory of gravity) to spin-1 massless particles.

G. Sparano; G. Vilasi; S. Vilasi

2010-09-12T23:59:59.000Z

80

Quantum gravity and "singularities"  

E-Print Network (OSTI)

The paper concerns the fictitious entanglement of the so-called ``singularities'' in problems, pertaining to quantum gravity, due, in point of fact, to the way we try to employ, in that context, differential geometry, the latter being associated, in effect, by far, classically (:smooth manifolds), on the basis of an erroneous correspondence between what we may call/understand, as ``physical space'' and the ``cartesian-newtonian'' one.

Anastasios Mallios

2004-05-20T23:59:59.000Z

Note: This page contains sample records for the topic "gravity astm american" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Lorentz Breaking and Gravity  

E-Print Network (OSTI)

Gravitational theories with Lorentz violation must account for a number of possible features in order to be consistent theoretically and phenomenologically. A brief summary of these features is given here. They include evasion of a no-go theorem, connections between spontaneous Lorentz breaking and diffeomorphism breaking, the appearance of massless Nambu-Goldstone modes and massive Higgs modes, and the possibility of a Higgs mechanism in gravity.

R. Bluhm

2013-07-22T23:59:59.000Z

82

Gravity, Dimension, Equilibrium, & Thermodynamics  

E-Print Network (OSTI)

Is it actually possible to interpret gravitation as space's property in a pure classical way. Then, we note that extended self-gravitating system equilibrium depends directly on the number of dimension of the space in which it evolves. Given those precisions, we review the principal thermodynamical knowledge in the context of classical gravity with arbitrary dimension of space. Stability analyses for bounded 3D systems, namely the Antonov instability paradigm, are then rapproched to some amazing properties of globular clusters and galaxies.

Jerome Perez

2006-03-30T23:59:59.000Z

83

The Particle Adventure | What holds it together? | Gravity  

NLE Websites -- All DOE Office Websites (Extended Search)

holds it together? > Gravity Gravity What about gravity? Gravity is weird. It is clearly one of the fundamental interactions, but the Standard Model cannot satisfactorily explain...

84

Gravity Methods | Open Energy Information  

Open Energy Info (EERE)

Gravity Methods Gravity Methods Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Gravity Methods Details Activities (0) Areas (0) Regions (0) NEPA(3) Exploration Technique Information Exploration Group: Geophysical Techniques Exploration Sub Group: Gravity Techniques Parent Exploration Technique: Information Provided by Technique Lithology: Stratigraphic/Structural: Hydrological: Thermal: Dictionary.png Gravity Methods: No definition has been provided for this term. Add a Definition References No exploration activities found. Document # Analysis Type Applicant Geothermal Area Lead Agency District Office Field Office Mineral Manager Surface Manager Development Phase(s) Techniques NVN-084630 CU Vulcan Energy Patua Geothermal Area BLM Nevada State Office BLM Winnemucca District Office BLM Humboldt River Field Office BLM BLM Geothermal/Exploration Gravity Methods

85

Entropic Gravity in Rindler Space  

E-Print Network (OSTI)

We show that Rindler horizons are entropic screens and gravity is an entropic force in Rindler space by deriving the Verlinde entropy formula from the focusing of light due to a mass close to the horizon. Consequently, gravity is also entropic in the near horizon regions of Schwarzschild and de Sitter space-times. In different limits, the entropic nature of gravity in Rindler space leads to the Bekenstein entropy bound and the uncertainty principle.

Halyo, Edi

2011-01-01T23:59:59.000Z

86

Entropic Gravity in Rindler Space  

E-Print Network (OSTI)

We show that Rindler horizons are entropic screens and gravity is an entropic force in Rindler space by deriving the Verlinde entropy formula from the focusing of light due to a mass close to the horizon. Consequently, gravity is also entropic in the near horizon regions of Schwarzschild and de Sitter space-times. In different limits, the entropic nature of gravity in Rindler space leads to the Bekenstein entropy bound and the uncertainty principle.

Edi Halyo

2011-04-13T23:59:59.000Z

87

Cascading gravity is ghost free  

SciTech Connect

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

Rham, Claudia de [Departement de Physique Theorique, Universite de Geneve, 24 Quai E. Ansermet, CH-1211 Geneve (Switzerland); Khoury, Justin [Center for Particle Cosmology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6395 (United States); Tolley, Andrew J. [Perimeter Institute for Theoretical Physics, 31 Caroline St. N., Waterloo, ON, N2L 2Y5 (Canada)

2010-06-15T23:59:59.000Z

88

D-dimensional log gravity  

SciTech Connect

We study Einstein gravity in dimensions D{>=}4 modified by curvature squared at critical point where the theory contains only massless gravitons. We show that at the critical point a new mode appears leading to a logarithmic gravity in the theory. The corresponding logarithmic solution may provide a gravity description of logarithmic conformal field theories (CFT) in higher dimensions. We note also that for special values of the parameters of the theory, the model admits solutions with nonrelativistic isometries.

Alishahiha, Mohsen; Fareghbal, Reza [School of physics, Institute for Research in Fundamental Sciences (IPM), P. O. Box 19395-5531, Tehran (Iran, Islamic Republic of)

2011-04-15T23:59:59.000Z

89

Is Gravity an Entropic Force?  

E-Print Network (OSTI)

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.

Shan Gao

2010-02-13T23:59:59.000Z

90

Topological methods in quantum gravity.  

E-Print Network (OSTI)

??The main technical problem with background independent approaches to quantum gravity is inapplicability of standard quantum field theory methods. New methods are needed which would… (more)

Starodubtsev, Artem

2005-01-01T23:59:59.000Z

91

Discrete gravity models and Loop Quantum Gravity: a short review  

E-Print Network (OSTI)

We review the relation between loop quantum gravity on a fixed graph and discrete models of gravity. We compare Regge and twisted geometries, and discuss discrete actions based on twisted geometries and on the discretization of the Plebanski action. We discuss the role of discrete geometries in the spin foam formalism, with particular attention to the definition of the simplicity constraints.

Dupuis, Maite; Speziale, Simone

2012-01-01T23:59:59.000Z

92

Gravity wraps Higgs boson  

E-Print Network (OSTI)

It is shown that, under a conformal transformation with reference to the Higgs field, the Higgs boson can be completely decoupled from electroweak interactions with no apparent change in known properties of leptons, quarks and vector bosons. Higgs boson becomes part of a scalar-tensor gravity which can be relevant for Dark Energy. It interacts with matter sector via higher-dimensional terms (e.g. neutrino Majorana mass), and via the fields (of new physics) whose masses are not generated by the Higgs mechanism. Dark Matter and two-Higgs-doublet model are the simplest examples.

Durmus A. Demir

2011-10-17T23:59:59.000Z

93

Deformed Einstein Gravity  

Science Conference Proceedings (OSTI)

We introduce the necessary concepts for an algebraic construction of a gravity theory on noncommutative spaces. The ??deformed diffeomorphisms are studied and a tensor calculus is defined. This leads to a deformed Einstein?Hilbert action which is invariant with respect to deformed diffeomorphisms. The dynamical variable is the vierbein field. The deformed action is a deformation of the usual Einstein?Hilbert action and reduces to it in the limit where the noncommutativity vanishes. This contribution is based on joint work with P. Aschieri

Frank Meyer

2006-01-01T23:59:59.000Z

94

Gravity-Driven Intrusions in Stratified Fluids  

E-Print Network (OSTI)

5.5.1 Five interleaving interfacial gravity currents 5.5.2Ten interleaving interfacial gravity currents . 5.6in Iceland showing multiple gravity-driven intrusions c ´

Maurer, Benjamin D.

2011-01-01T23:59:59.000Z

95

The role of information in gravity  

E-Print Network (OSTI)

It is argued that particle-specific information on energy-momentum adjusts the strength of gravity. This form of gravity has no free parameters, preserves Einstein gravity locally and predicts 6 times stronger accelerations on galaxy scales.

M. Spaans

2009-03-25T23:59:59.000Z

96

Definition: Airborne Gravity Survey | Open Energy Information  

Open Energy Info (EERE)

Survey Jump to: navigation, search Dictionary.png Airborne Gravity Survey Airborne gravity gradiometry (AGG) surveys provide information regarding the mass distribution of the...

97

Lovelock gravity from entropic force  

E-Print Network (OSTI)

In this paper, we first generalize the formulation of entropic gravity to (n+1)-dimensional spacetime. Then, we propose an entropic origin for Gauss-Bonnet gravity and more general Lovelock gravity in arbitrary dimensions. As a result, we are able to derive Newton's law of gravitation as well as the corresponding Friedmann equations in these gravity theories. This procedure naturally leads to a derivation of the higher dimensional gravitational coupling constant of Friedmann/Einstein equation which is in complete agreement with the results obtained by comparing the weak field limit of Einstein equation with Poisson equation in higher dimensions. Our study shows that the approach presented here is powerful enough to derive the gravitational field equations in any gravity theory. PACS: 04.20.Cv, 04.50.-h, 04.70.Dy.

A. Sheykhi; H. Moradpour; N. Riazi

2011-09-11T23:59:59.000Z

98

Gravity Waves in the Sun  

E-Print Network (OSTI)

We present numerical simulations of penetrative convection and gravity wave excitation in the Sun. Gravity waves are self-consistently generated by a convective zone overlying a radiative interior. We produce power spectra for gravity waves in the radiative region as well as estimates for the energy flux of gravity waves below the convection zone. We calculate a peak energy flux in waves below the convection zone to be three orders of magnitude smaller than previous estimates for m=1. The simulations show that the linear dispersion relation is a good approximation only deep below the convective-radiative boundary. Both low frequency propagating gravity waves as well as higher frequency standing modes are generated; although we find that convection does not continually drive the standing g-mode frequencies.

Tamara M. Rogers; Gary A. Glatzmaier

2005-08-25T23:59:59.000Z

99

Gravity quantized: Loop quantum gravity with a scalar field  

Science Conference Proceedings (OSTI)

...''but we do not have quantum gravity.'' This phrase is often used when analysis of a physical problem enters the regime in which quantum gravity effects should be taken into account. In fact, there are several models of the gravitational field coupled to (scalar) fields for which the quantization procedure can be completed using loop quantum gravity techniques. The model we present in this paper consists of the gravitational field coupled to a scalar field. The result has similar structure to the loop quantum cosmology models, except that it involves all the local degrees of freedom of the gravitational field because no symmetry reduction has been performed at the classical level.

Domagala, Marcin; Kaminski, Wojciech [Instytut Fizyki Teoretycznej, Uniwersytet Warszawski, ul. Hoza 69, 00-681 Warszawa (Warsaw), Polska (Poland) (Poland); Giesel, Kristina [Excellence Cluster Universe, Technische Universitaet Muenchen, Boltzmannstrasse 2, 85748 Garching (Germany); Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Lewandowski, Jerzy [Instytut Fizyki Teoretycznej, Uniwersytet Warszawski, ul. Hoza 69, 00-681 Warszawa (Warsaw), Polska (Poland) (Poland); Institute for Gravitation and the Cosmos, Physics Department, Penn State, University Park, Pennsylvania 16802 (United States)

2010-11-15T23:59:59.000Z

100

Uptakes of Cs and Sr on San Joaquin soil measured following ASTM method C1733.  

SciTech Connect

Series of tests were conducted following ASTM Standard Procedure C1733 to evaluate the repeatability of the test and the effects of several test parameters, including the solution-to-soil mass ratio, test duration, pH, and the concentrations of contaminants in the solution. This standard procedure is recommended for measuring the distribution coefficient (K{sub d}) of a contaminant in a specific soil/groundwater system. One objective of the current tests was to identify experimental conditions that can be used in future interlaboratory studies to determine the reproducibility of the test method. This includes the recommendation of a standard soil, the range of contaminant concentrations and solution matrix, and various test parameters. Quantifying the uncertainty in the distribution coefficient that can be attributed to the test procedure itself allows the differences in measured values to be associated with differences in the natural systems being studied. Tests were conducted to measure the uptake of Cs and Sr dissolved as CsCl and Sr(NO{sub 3}){sub 2} in a dilute NaHCO{sub 3}/SiO{sub 2} solution (representing contaminants in a silicate groundwater) by a NIST standard reference material of San Joaquin soil (SRM 2709a). Tests were run to measure the repeatability of the method and the sensitivity of the test response to the reaction time, the mass of soil used (at a constant soil-to-solution ratio), the solution pH, and the contaminant concentration. All tests were conducted in screw-top Teflon vessels at 30 C in an oven. All solutions were passed through a 0.45-{mu}m pore size cellulose acetate membrane filter and stabilized with nitric acid prior to analysis with inductively-coupled plasma mass spectrometry (ICP-MS). Scoping tests with soil in demineralized water resulted in a solution pH of about 8.0 and the release of small amounts of Sr from the soil. Solutions were made with targeted concentrations of 1 x 10{sup -6} m, 1 x 10{sup -5} m, 2.5 x 10{sup -5} m, 5 x 10{sup -5} m, 1 x 10{sup -4} m, and 5 x 10{sup -4} m to measure the effects of the Cs and Sr concentrations on their uptake by the soil. The pH values of all solutions were adjusted to about pH 8.5 so that the effects of pH and concentration could be measured separately. The 1 x 10{sup -4} m solutions were used to measure the repeatability of the test and the effects of duration, scale, and imposed pH on the test response.

Ebert, W.L.; Petri, E.T. (Chemical Sciences and Engineering Division)

2012-04-04T23:59:59.000Z

Note: This page contains sample records for the topic "gravity astm american" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Quantum Histories and Quantum Gravity  

E-Print Network (OSTI)

This paper reviews the histories approach to quantum mechanics. This discussion is then applied to theories of quantum gravity. It is argued that some of the quantum histories must approximate (in a suitable sense) to classical histories, if the correct classical regime is to be recovered. This observation has significance for the formulation of new theories (such as quantum gravity theories) as it puts a constraint on the kinematics, if the quantum/classical correspondence principle is to be preserved. Consequences for quantum gravity, particularly for Lorentz symmetry and the idea of "emergent geometry", are discussed.

Joe Henson

2009-01-26T23:59:59.000Z

102

Oklahoma, Kansas, Missouri Refinery District API Gravity ...  

U.S. Energy Information Administration (EIA)

Oklahoma, Kansas, Missouri Refinery District API Gravity (Weighted Average) of Crude Oil Input to Refineries (Degree)

103

Intrusive gravity currents in two-layer  

E-Print Network (OSTI)

Intrusive gravity currents in two-layer stratified media Morris R. Flynn & Paul F. Linden Dept to as a gravity current · In contrast to waves, gravity currents transport significant mass (e.g. fluid parcels, sediment, insects, etc.) Introduction Gravity currents in the environment www

Flynn, Morris R.

104

Spin-gravity coupling and gravity-induced quantum phases  

E-Print Network (OSTI)

External gravitational fields induce phase factors in the wave functions of particles. The phases are exact to first order in the background gravitational field, are manifestly covariant and gauge invariant and provide a useful tool for the study of spin-gravity coupling and of the optics of particles in gravitational or inertial fields. We discuss the role that spin-gravity coupling plays in particular problems.

Giorgio Papini

2007-09-06T23:59:59.000Z

105

PPN-limit of Fourth Order Gravity inspired by Scalar-Tensor Gravity  

E-Print Network (OSTI)

Based on the {\\it dynamical} equivalence between higher order gravity and scalar-tensor gravity the PPN-limit of fourth order gravity is discussed. We exploit this analogy developing a fourth order gravity version of the Eddington PPN-parameters. As a result, Solar System experiments can be reconciled with higher order gravity, if physical constraints descending from experiments are fulfilled.

S. Capozziello; A. Troisi

2005-07-22T23:59:59.000Z

106

Gravity's Cosmic ShadowsGravity's Cosmic Shadows A Mathematical UnveilingA Mathematical Unveiling  

E-Print Network (OSTI)

Gravity's Cosmic ShadowsGravity's Cosmic Shadows A Mathematical UnveilingA Mathematical Unveiling of gravity on light SUNSUN #12;Gravitational Lensing - action of gravity on light SUNSUN #12;Gravitational Lensing - action of gravity on light SUNSUN nn 1801: Johann von1801: Johann von SoldnerSoldner (Newtonian

Weinberger, Hans

107

Gravity Techniques | Open Energy Information  

Open Energy Info (EERE)

Gravity Techniques Gravity Techniques Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Gravity Techniques Details Activities (0) Areas (0) Regions (0) NEPA(1) Exploration Technique Information Exploration Group: Geophysical Techniques Exploration Sub Group: Gravity Techniques Parent Exploration Technique: Geophysical Techniques Information Provided by Technique Lithology: Distribution of density in the subsurface enables inference of rock type. Stratigraphic/Structural: Delineation of steeply dipping formations, geological discontinuities and faults, intrusions and the deposition of silicates due to hydrothermal activity. Hydrological: Density of sedimentary rocks are strongly influenced by fluid contained within pore space. Dry bulk density refers to the rock with no moisture, while the wet bulk density accounts for water saturation; fluid content may alter density by up to 30%.(Sharma, 1997)

108

Numerical Dispersion of Gravity Waves  

Science Conference Proceedings (OSTI)

When atmospheric gravity waves are simulated in numerical models, they are not only dispersive for physical but also for numerical reasons. Their wave properties (e.g., damping or propagation speed and direction) can depend on grid spacing as ...

Guido Schroeder; K. Heinke Schlünzen

2009-12-01T23:59:59.000Z

109

Critical Gravity in Four Dimensions  

SciTech Connect

We study four-dimensional gravity theories that are rendered renormalizable by the inclusion of curvature-squared terms to the usual Einstein action with a cosmological constant. By choosing the parameters appropriately, the massive scalar mode can be eliminated and the massive spin-2 mode can become massless. This ''critical'' theory may be viewed as a four-dimensional analogue of chiral topologically massive gravity, or of critical 'new massive gravity' with a cosmological constant, in three dimensions. We find that the on-shell energy for the remaining massless gravitons vanishes. There are also logarithmic spin-2 modes, which have positive energy. The mass and entropy of standard Schwarzschild-type black holes vanish. The critical theory might provide a consistent toy model for quantum gravity in four dimensions.

Lue, H. [China Economics and Management Academy, Central University of Finance and Economics, Beijing 100081 (China); Institute for Advanced Study, Shenzhen University, Nanhai Avenue 3688, Shenzhen 518060 (China); Pope, C. N. [George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A and M University, College Station, Texas 77843 (United States); DAMTP, Centre for Mathematical Sciences, Cambridge University, Wilberforce Road, Cambridge CB3 OWA (United Kingdom)

2011-05-06T23:59:59.000Z

110

Structure formation in modified gravity  

Science Conference Proceedings (OSTI)

We pursue a (1+3) ?covariant analysis of cosmological peculiar velocity of pressure?free matter induced by the matter density perturbations in modified f(R) gravity theories. Instead of working in a quasi?Newtonian Eulerian frame

D. M. Solomons; P. K. S. Dunsby; S. Carloni

2009-01-01T23:59:59.000Z

111

Identifying Student Concepts of Gravity.  

E-Print Network (OSTI)

??This paper discusses a survey developed to investigate student concepts of "gravity" among AST 109 astronomy students and pre-service K-12 teachers. Survey questions were developed… (more)

Feeley, Roger Eastman

2007-01-01T23:59:59.000Z

112

Gravity Currents in Aquatic Canopies  

E-Print Network (OSTI)

A lock exchange experiment is used to investigate the propagation of gravity currents through a random array of rigid, emergent cylinders which represents a canopy of aquatic plants. As canopy drag increases, the propagating ...

Tanino, Yukie

113

Momentum Balance of Gravity Flows  

Science Conference Proceedings (OSTI)

A unified scale analysis of the momentum balance of downslope gravity flows is developed to organize previous theories for the case of negligible ambient flow and fixed temperature deficit scale. The values of several nondimensional parameters ...

L. Mahrt

1982-12-01T23:59:59.000Z

114

Quench cooling under reduced gravity  

E-Print Network (OSTI)

We report the quench cooling experiments performed with liquid O2 under different levels of gravity simulated with the magnetic gravity compensation. A copper disk is quenched from 270K to 90K. It is found that the cooling time in microgravity is very long in comparison with any other gravity level. This phenomenon is explained by the isolation effect of the gas surrounding the disk. The liquid subcooling is shown to drastically improuve the heat exchange thus reducing the cooling time (about 20 times). The effect of subcooling on the heat transfer is analyzed at different gravity levels. It is shown that such type of experiments cannot be used for the analysis of the critical heat flux (CHF) of the boiling crisis. The minimum heat flux (MHF) of boiling is analyzed instead.

Chatain, D; Nikolayev, V S; Beysens, D

2013-01-01T23:59:59.000Z

115

Attractions of Affine Quantum Gravity  

E-Print Network (OSTI)

All attempts to quantize gravity face several difficult problems. Among these problems are: (i) metric positivity (positivity of the spatial distance between distinct points), (ii) the presence of anomalies (partial second-class nature of the quantum constraints), and (iii) perturbative nonrenormalizability (the need for infinitely many distinct counterterms). In this report, a relatively nontechnical discussion is presented about how the program of affine quantum gravity proposes to deal with these problems.

John R. Klauder

2004-11-10T23:59:59.000Z

116

Lectures on Screened Modified Gravity  

E-Print Network (OSTI)

The acceleration of the expansion of the Universe has led to the construction of Dark Energy models where a light scalar field may have a range reaching up to cosmological scales. Screening mechanisms allow these models to evade the tight gravitational tests in the solar system and the laboratory. I will briefly review some of the salient features of screened modified gravity models of the chameleon, dilaton or symmetron types using $f(R)$ gravity as a template.

Philippe Brax

2012-11-22T23:59:59.000Z

117

Observational Tests of Modified Gravity  

E-Print Network (OSTI)

Modified gravity theories have richer observational consequences for large-scale structure 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 ISW 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 breaks 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).

Bhuvnesh Jain; Pengjie Zhang

2007-09-17T23:59:59.000Z

118

Dilaton Gravity, Poisson Sigma Models and Loop Quantum Gravity  

E-Print Network (OSTI)

Spherically symmetric gravity in Ashtekar variables coupled to Yang-Mills theory in two dimensions and its relation to dilaton gravity and Poisson sigma models are discussed. After introducing its loop quantization, quantum corrections for inverse triad components are shown to provide a consistent deformation without anomalies. The relation to Poisson sigma models provides a covariant action principle of the quantum corrected theory with effective couplings. Results are also used to provide loop quantizations of spherically symmetric models in arbitrary D space-time dimensions.

Martin Bojowald; Juan D. Reyes

2008-10-28T23:59:59.000Z

119

Modified gravity from the quantum part of the metric  

E-Print Network (OSTI)

It is shown that if a metric in quantum gravity can be decomposed as a sum of classical and quantum parts then Einstein quantum gravity looks approximately like modified gravity with a nonminimal interaction between gravity and matter.

Vladimir Dzhunushaliev; Vladimir Folomeev; Burkhard Kleihaus; Jutta Kunz

2013-12-01T23:59:59.000Z

120

Enhanced and Inhibited Gravity Wave Spectra  

Science Conference Proceedings (OSTI)

Balloon measurements were used to investigate gravity waves in the upper troposphere and lower stratosphere above the Canadian high Arctic. The amount of gravity wave activity in the stratosphere was found to be related to particular ...

James A. Whiteway

1999-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "gravity astm american" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Questions and Answers - Does gravity affect atoms?  

NLE Websites -- All DOE Office Websites (Extended Search)

and Answers Main Index Next Question (Can you crush atoms?) Can you crush atoms? Does gravity affect atoms? Gravity affects atoms the same way it affects all other matter. Every...

122

A Coherent Strategy for Qauntum Gravity  

E-Print Network (OSTI)

Affine quantum gravity, which differs notably from either string theory or loop quantum gravity, is briefly reviewed. Emphasis in this article is placed on the use of affine coherent states in this program.

John R. Klauder

2004-11-10T23:59:59.000Z

123

New models of f(R) theories of gravity  

SciTech Connect

We introduce new models of f(R) theories of gravity that are a generalization of Horava-Lifshitz gravity.

Kluson, J. [Department of Theoretical Physics and Astrophysics, Faculty of Science, Masaryk University, Kotlarska 2, 611 37, Brno (Czech Republic)

2010-03-15T23:59:59.000Z

124

New Models of f(R) Theories of Gravity  

E-Print Network (OSTI)

We introduce new models of f(R) theories of gravity that are generalization of Horava-Lifshitz gravity.

J. Kluson

2009-10-30T23:59:59.000Z

125

New Models of f(R) Theories of Gravity  

E-Print Network (OSTI)

We introduce new models of f(R) theories of gravity that are generalization of Horava-Lifshitz gravity.

Kluson, J

2009-01-01T23:59:59.000Z

126

Rapid gravity and gravity gradiometry terrain corrections via an adaptive quadtree mesh discretization  

E-Print Network (OSTI)

Rapid gravity and gravity gradiometry terrain corrections via an adaptive quadtree mesh discretization Kristofer Davis1,2 M. Andy Kass1 Yaoguo Li1 1 Center for Gravity, Electrical, and Magnetic Studies of gravity gradiometry surveys utilising an adaptive quadtree mesh discretization. The data- and terrain

127

Unification of Gravity and Electromagnetism Revisited  

E-Print Network (OSTI)

Unification of gravity and electromagnetism based on a theory with an affine non-symmetric connection $\\Gamma^\\lambda_{\\mu\

Partha Ghose

2013-02-14T23:59:59.000Z

128

A gravity term from spontaneous symmetry breaking  

E-Print Network (OSTI)

In this model, the gravity term in the Lagrangean comes from spontaneous symmetry breaking of an additional scalar quadruplet field $\\Upsilon$. The resulting gravitational field is approximate to one of the models of coframe gravity with parameters $\\rho_1 + 4 \\rho_2 = 0$, $\\rho_3 = 0$. This article includes an exact solution of coframe gravity with model parameters $\\rho_1 \

Mihai Moise

2014-01-02T23:59:59.000Z

129

Gravity Transform for Input Conditioning in  

E-Print Network (OSTI)

Gravity Transform for Input Conditioning in Brain Machine Interfaces António R. C. Paiva, José C. Motivation 2. Methods i. Gravity Transform ii. Modeling and output sensitivity analysis 3. Data Analysis #12;3 Outline 1. Motivation 2. Methods i. Gravity Transform ii. Modeling and output sensitivity analysis 3. Data

Paiva, António R. C.

130

Momentum Transport by Gravity Waves  

Science Conference Proceedings (OSTI)

The momentum flux by orographic gravity waves and the turbulent heat flux in wave-breaking regions are estimated from aircraft data from ALPEX. The fluxes on 6 March 1982 are controlled by low-level directional shear of the mean flow and ...

Jinwon Kim; L. Mahrt

1992-05-01T23:59:59.000Z

131

Overlap Fermion in External Gravity  

E-Print Network (OSTI)

On a lattice, we construct an overlap Dirac operator which describes the propagation of a Dirac fermion in external gravity. The local Lorentz symmetry is manifestly realized as a lattice gauge symmetry, while the general coordinate invariance is expected to be restored only in the continuum limit. The lattice index density in the presence of a gravitational field is calculated.

Hiroto So; Masashi Hayakawa; Hiroshi Suzuki

2006-10-04T23:59:59.000Z

132

High-gravity central stars  

E-Print Network (OSTI)

NLTE spectral analyses of high-gravity central stars by means of state-of-the-art model atmosphere techniques provide information about the precursor AGB stars. The hydrogen-deficient post-AGB stars allow investigations on the intershell matter which is apparently exhibited at the stellar surface. We summarize recent results from imaging, spectroscopy, and spectropolarimetry.

Thomas Rauch

2006-07-11T23:59:59.000Z

133

Rheological measurements in reduced gravity  

Science Conference Proceedings (OSTI)

Rheology of fluidized beds and settling suspensions were studied experimentally in a series of reduced gravity parabolic flights aboard NASA’s KC?135 aircraft. Silica sands of two different size distributions were fluidized by air. The slurries were made using silica sand and Glycerol solution. The experimental set up incorporated instrumentation to measure the air flow rate

Sayavur I. Bakhtiyarov; Ruel A. Overfelt

1999-01-01T23:59:59.000Z

134

Gravity and the Fermion Mass  

E-Print Network (OSTI)

It is shown that gravity generates mass for the fermion. It does so by coupling directly with the spinor field. The coupling term is invariant with respect to the electroweak gauge group $ U(1) \\otimes SU(2)_L. $ It replaces the fermion mass term $ m\\bar{\\psi} \\psi $.

Kenneth Dalton

2004-09-08T23:59:59.000Z

135

Fundamental decoherence in quantum gravity  

E-Print Network (OSTI)

A recently introduced discrete formalism allows to solve the problem of time in quantum gravity in a relational manner. Quantum mechanics formulated with a relational time is not exactly unitary and implies a fundamental mechanism for decoherence of quantum states. The mechanism is strong enough to render the black hole information puzzle unobservable.

Rodolfo Gambini; Rafael Porto; Jorge Pullin

2005-01-09T23:59:59.000Z

136

Schrodinger-like (Dilaton-)Gravity  

E-Print Network (OSTI)

We investigate possibilities for the Schrodinger-like gravity with the dynamical critical exponent z=2, where the action only contains the first-order time derivative. The Horava gravity always admits such a relevant deformation because the full (d+1) dimensional diffeomorphism of the Einstein gravity is replaced by the foliation preserving diffeomorphism. The dynamics is locally trivial or topological for the pure gravity case, but we can construct a dynamical field theory with z=2 dispersion relation by introducing a dilaton degree of freedom. Our model gives birth to a new model for quantum (dilaton-)gravity which may be applied to a membrane quantization.

Nakayama, Yu

2010-01-01T23:59:59.000Z

137

Narrow groove gas tungsten arc welding of ASTM A508 Class 4 steel for improved toughness properties  

Science Conference Proceedings (OSTI)

Welding of heavy section steel has traditionally used the automatic submerged arc welding (ASAW) process because of the high deposition rates achievable. However, the properties, particularly fracture toughness, of the weld are often inferior when compared to base material. This project evaluated the use of narrow groove gas tungsten arc welding (GTAW) to improve weld material properties. The welding procedures were developed for ASTM A508 Class 4 base material using a 1% Ni filler material complying to AWS Specification A.23-90-EF3-F3-N. A narrow groove joint preparation was used in conjunction with the GTAW process so competitive fabrication rates could be achieved when compared to the ASAW process. Weld procedures were developed to refine weld substructure to achieve better mechanical properties. Two heaters of weld wire were used to examine the effects of minor filler metal chemistry differences on weld mechanical properties. Extensive metallographic evaluations showed excellent weld quality with a refined microstructure. Chemical analysis of the weld metal showed minimal weld dilution by the base metal. Mechanical testing included bend and tensile tests to ensure weld quality and strength. A Charpy impact energy curve versus temperature and fracture toughness curve versus temperature were developed for each weld wire heat. Results of fracture toughness and Charpy impact testing indicated an improved transition temperature closer to that of the base material properties.

Penik, M.A. Jr. [Rensselaer Polytechnic Inst., Troy, NY (United States)

1997-04-01T23:59:59.000Z

138

A modified ASTM G-75 abrasion test helps select candidate alloys for service in a corrosive and abrasive slurry  

SciTech Connect

The design of a hazardous waste immobilization facility at the Savannah River Site (SRS) set material requirements for both abrasion resistance and corrosion resistance in process equipment. Standard ASTM slurry wear test G75 was modified to permit evaluation and comparison of abrasive resistance of candidate materials of construction in the laboratory. However, corrosion was found to contribute significantly to overall metal loss during the testing. Consequently, the abrasive slurry used for the testing was modified by adjusting its chemistry to include appropriate corrosive species. The Miller numbers obtained in the modified G75 Miller abrasion test are described. Pilot plant observations for Type 304L austenitic stainless steel were available. These data were used to generate a Morrison-Miller Ratio'' in order to determine anticipated field abrasion properties for other alloys. Hardness for many of the alloys fell in a narrow range about Rockwell B90, but performance varied significantly in response to slurry chemistry. This effect if synergistic may often be overlooked in the selection process, and it needs to be addressed. Some pilot plant testing of other alloys is essential to confirm the calculated abrasion rates and the approach of using the Morrison-Miller ratio. 6 refs., 3 figs., 5 tabs.

Corbett, R.A.; Morrison, W.S.; Jenkins, C.F. (Corrosion Testing Labs., Inc., Wilmington, DE (USA); Westinghouse Savannah River Co., Aiken, SC (USA))

1989-01-01T23:59:59.000Z

139

The Dark Gravity model predictions for Gravity Probe B  

E-Print Network (OSTI)

The previous version of this article gave erroneous predictions. The correct uptodate predictions can be found in the section devoted to gravitomagnetism in the living review of the Dark Gravity theory: gr-qc/0610079 The most natural prediction is zero frame dragging and the same geodetic effect as predicted by GR. However, a straightforward extension of the theory could lead to the same frame-dragging as in GR.

Frederic Henry-Couannier

2005-09-05T23:59:59.000Z

140

Quantum Gravity at the LHC  

E-Print Network (OSTI)

It has recently been shown that if there is a large hidden sector in Nature, the scale of quantum gravity could be much lower than traditionally expected. We study the production of massless gravitons at the LHC and compare our results to those obtained in extra dimensional models. The signature in both cases is missing energy plus jets. In case of non observation, the LHC could be used to put the tightest limit to date on the value of the Planck mass.

Xavier Calmet; Priscila de Aquino

2009-06-02T23:59:59.000Z

Note: This page contains sample records for the topic "gravity astm american" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Dark Energy and Dark Gravity  

E-Print Network (OSTI)

Observations provide increasingly strong evidence that the universe is accelerating. This revolutionary advance in cosmological observations confronts theoretical cosmology with a tremendous challenge, which it has so far failed to meet. Explanations of cosmic acceleration within the framework of general relativity are plagued by difficulties. General relativistic models are nearly all based on a dark energy field with fine-tuned, unnatural properties. There is a great variety of models, but all share one feature in common -- an inability to account for the gravitational properties of the vacuum energy. Speculative ideas from string theory may hold some promise, but it is fair to say that no convincing model has yet been proposed. An alternative to dark energy is that gravity itself may behave differently from general relativity on the largest scales, in such a way as to produce acceleration. The alternative approach of modified gravity (or dark gravity) provides a new angle on the problem, but also faces serious difficulties, including in all known cases severe fine-tuning and the problem of explaining why the vacuum energy does not gravitate. The lack of an adequate theoretical framework for the late-time acceleration of the universe represents a deep crisis for theory -- but also an exciting challenge for theorists. It seems likely that an entirely new paradigm is required to resolve this crisis.

Ruth Durrer; Roy Maartens

2007-11-01T23:59:59.000Z

142

Dynamical 3-Space: Emergent Gravity  

E-Print Network (OSTI)

The laws of gravitation devised by Newton, and by Hilbert and Einstein, have failed many experimental and observational tests, namely the bore hole g anomaly, flat rotation curves for spiral galaxies, supermassive black hole mass spectrum, uniformly expanding universe, cosmic filaments, laboratory G measurements, galactic EM bending, precocious galaxy formation,.. The response has been the introduction of the new epicycles: ``dark matter", ``dark energy", and others. To understand gravity we must restart with the experimental discoveries by Galileo, and following a heuristic argument we are led to a uniquely determined theory of a dynamical 3-space. That 3-space exists has been missed from the beginning of physics, although it was 1st directly detected by Michelson and Morley in 1887. Uniquely generalising the quantum theory to include this dynamical 3-space we deduce the response of quantum matter and show that it results in a new account of gravity, and explains the above anomalies and others. The dynamical theory for this 3-space involves G, which determines the dissipation rate of space by matter, and alpha, which experiments and observation reveal to be the fine structure constant. For the 1st time we have a comprehensive account of space and matter and their interaction - gravity.

Reginald T Cahill

2011-02-16T23:59:59.000Z

143

American Goldfinch  

NLE Websites -- All DOE Office Websites (Extended Search)

American Goldfinch American Goldfinch Name: Mary-Ellen Location: N/A Country: N/A Date: N/A Question: I happened on an American Goldfinch in my yard last week who could not fly. I captured it and now have it living in a large box. I have been feeding it commericial wild finch seed, niger seed and some sunflower seed. I have also provided a small cup of fine sand and a dish of water. Am I missing anything in it's diet? I had hoped to find someone to take it and care for it until it could fly again but have been unsuccessful so I may end up caring for it. It's wing is not visibly injured, however it can only flutter. I have been caring for it for 6 days now and it appears OK. Have also provided it with a small perch (branch) which it seems to use most of the time. Any other suggestions?

144

Spectral Estimates of Gravity Wave Energy and Momentum Fluxes. Part III: Gravity Wave-Tidal Interactions  

Science Conference Proceedings (OSTI)

An application of the gravity wave parameterization scheme developed in the companion papers by Fritts and VanZandt and Fritts and Lu to the mutual interaction of gravity waves and tidal motions is presented. The results suggest that interaction ...

Wentong Lu; David C. Fritts

1993-11-01T23:59:59.000Z

145

Born-Infeld gravity in three dimensions  

Science Conference Proceedings (OSTI)

In this paper we explore different aspects of three dimensional Born-Infeld as well as Born-Infeld-Chern-Simons gravity. We show that the models have anti-de Sitter and anti-de Sitter wave vacuum solutions. Moreover, we observe that although Born-Infeld-Chern-Simons gravity admits a logarithmic solution, Born-Infeld gravity does not, though it has a limiting logarithmic solution as we approach the critical point.

Alishahiha, Mohsen [School of physics, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Naseh, Ali [School of physics, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Department of Physics, Sharif University of Technology, P.O. Box 11365-9161, Tehran (Iran, Islamic Republic of); Soltanpanahi, Hesam [School of physics, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); School of Physics and Centre for Theoretical Physics, University of the Witwatersrand, WITS 2050 Johannesburg (South Africa)

2010-07-15T23:59:59.000Z

146

Static solutions for fourth order gravity  

SciTech Connect

The Lichnerowicz and Israel theorems are extended to higher order theories of gravity. In particular it is shown that Schwarzschild is the unique spherically symmetric, static, asymptotically flat, black-hole solution, provided the spatial curvature is less than the quantum gravity scale outside the horizon. It is then shown that in the presence of matter (satisfying certain positivity requirements), the only static and asymptotically flat solutions of general relativity that are also solutions of higher order gravity are the vacuum solutions.

Nelson, William [Institute of Gravitation and the Cosmos, Penn State University, State College, Pennsylvania 16801 (United States)

2010-11-15T23:59:59.000Z

147

Quantum Gravity: Has Spacetime Quantum Properties?  

E-Print Network (OSTI)

The incompatibility between GR and QM is generally seen as a sufficient motivation for the development of a theory of Quantum Gravity. If - so a typical argumentation - QM gives a universally valid basis for the description of all natural systems, then the gravitational field should have quantum properties. Together with the arguments against semi-classical theories of gravity, this leads to a strategy which takes a quantization of GR as the natural avenue to Quantum Gravity. And a quantization of the gravitational field would in some sense correspond to a quantization of geometry. Spacetime would have quantum properties. But, this strategy will only be successful, if gravity is a fundamental interaction. - What, if gravity is instead an intrinsically classical phenomenon? Then, if QM is nevertheless fundamentally valid, gravity can not be a fundamental interaction. An intrinsically classical gravity in a quantum world would have to be an emergent, induced or residual, macroscopic effect, caused by other interactions. The gravitational field (as well as spacetime) would not have any quantum properties. A quantization of GR would lead to artifacts without any relation to nature. The serious problems of all approaches to Quantum Gravity that start from a direct quantization of GR or try to capture the quantum properties of gravity in form of a 'graviton' dynamics - together with the, meanwhile, rich spectrum of approaches to an emergent gravity and/or spacetime - make this latter option more and more interesting for the development of a theory of Quantum Gravity. The most advanced emergent gravity (and spacetime) scenarios are of an information-theoretical, quantum-computational type.

Reiner Hedrich

2009-02-02T23:59:59.000Z

148

Simultaneous measurement of gravity acceleration and gravity gradient with an atom interferometer  

SciTech Connect

We demonstrate a method to measure the gravitational acceleration with a dual cloud atom interferometer; the use of simultaneous atom interferometers reduces the effect of seismic noise on the gravity measurement. At the same time, the apparatus is capable of accurate measurements of the vertical gravity gradient. The ability to determine the gravity acceleration and gravity gradient simultaneously and with the same instrument opens interesting perspectives in geophysical applications.

Sorrentino, F.; Lien, Y.-H.; Rosi, G.; Tino, G. M. [Dipartimento di Fisica e Astronomia and LENS, Universita di Firenze, INFN Sezione di Firenze, via Sansone 1, I-50019 Sesto Fiorentino (Italy); Bertoldi, A. [Laboratoire Charles Fabry de l'Institut d'Optique, CNRS and Universite Paris-Sud Campus Polytechnique, RD 128, F-91127 Palaiseau cedex (France); Bodart, Q. [Dipartimento di Fisica e Astronomia and LENS, Universita di Firenze, INFN Sezione di Firenze, via Sansone 1, I-50019 Sesto Fiorentino (Italy); European Space Agency, Research and Scientific Support Department, Keplerlaan 1, 2201 AZ Noordwijk (Netherlands); Cacciapuoti, L. [European Space Agency, Research and Scientific Support Department, Keplerlaan 1, 2201 AZ Noordwijk (Netherlands); Angelis, M. de [Istituto di Fisica Applicata 'Nello Carrara' CNR, via Madonna del Piano 10, I-50019 Sesto Fiorentino (Italy); Prevedelli, M. [Dipartimento di Fisica dell'Universita di Bologna, Via Irnerio 46, I-40126, Bologna (Italy)

2012-09-10T23:59:59.000Z

149

Lovelock gravity is equivalent to Einstein gravity coupled to form fields  

E-Print Network (OSTI)

Lovelock gravity is a class of higher-derivative gravitational theories whose linearized equations of motion have no more than two time derivatives. Here, it is shown that any Lovelock theory can be effectively described as Einstein gravity coupled to a p-form gauge field. This extends the known example of an f(R) theory of gravity, which can be described as Einstein gravity coupled to a scalar field.

Brustein, Ram

2012-01-01T23:59:59.000Z

150

ASTM G 75 Tests  

Science Conference Proceedings (OSTI)

Table 1   Typical Miller numbers for selected slurry materials...51, 68, 85, 116, 138, 149, 246 Sea bottom 11 Shale 53, 59 Serpentine 134 Sewage, digested 15 Sewage, raw 25 Sodium sulfate 4 Soda ash tailings 27 Sulfur 1 Tailings (all types) 24, 61, 91, 159, 217, 480, 644 Tar sand 70 Waste, nickel 53 Waste, coal 22, 28...

151

Cosmological Acceleration: Dark Energy or Modified Gravity?  

E-Print Network (OSTI)

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 Dark Energy constituent. 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 alone, but requires also observing the growth of inhomogeneities. Present and projected observations are all consistent with a small fine tuned cosmological constant, with nearly static Dark Energy, or with gravity modified at cosmological scales. The growth of cosmological fluctuations will potentially distinguish static "dark energy" from dynamic "dark energy" with equation of state $w(z)$ either changing rapidly or tracking the background matter. But to cosmologically distinguish $\\Lambda$CDM from modified gravity will require a weak lensing shear survey more ambitious than any now projected. Dvali-Gabadadze-Porrati modifications of Einstein gravity may also be detected in refined bservations in the solar system or at the intermediate Vainstein scale. Dark Energy's epicyclic character, failure to explain the original Cosmic Coincidence ("Why 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.

Sidney Bludman

2006-05-08T23:59:59.000Z

152

Gravity Gold Concentration at Newmont Mining  

Science Conference Proceedings (OSTI)

Abstract Scope, The process of gold recovery by gravity concentration is incorporated ... Energy Management Planning, Following the ISO 50001 Draft Standard.

153

Optimising Circuit Design for Gravity Gold Recovery  

Science Conference Proceedings (OSTI)

Abstract Scope, To determine the optimal circuit configuration for gravity gold recovery ... Energy Management Planning, Following the ISO 50001 Draft Standard.

154

Thermophysical Property Measurements Under Reduced Gravity ...  

Science Conference Proceedings (OSTI)

Presentation Title, Thermophysical Property Measurements Under Reduced Gravity Conditions: Evolution and Status of theThermoLab Project. Author(s), H-J

155

Gravity from the extension of spatial diffeomorphisms  

E-Print Network (OSTI)

The possibility of the extension of spatial diffeomorphisms to a larger family of symmetries in a class of classical field theories is studied. The generator of the additional local symmetry contains a quadratic kinetic term and a potential term which can be a general (not necessarily local) functional of the metric. From the perspective of the foundation of Einstein's gravity our results are positive: The extended constraint algebra is either that of Einstein's gravity, or ultralocal gravity. If our goal is a simple modification of Einstein's gravity that for example makes it perturbatively renormalizable, as has recently been suggested, then our results show that there is no such theory within this class.

Szilard Farkas; Emil J. Martinec

2010-02-24T23:59:59.000Z

156

Palatini formulation of L(R) gravity  

E-Print Network (OSTI)

We review the Palatini formulation of the higher-derivative gravity of the $L(R)$ form and its applications in cosmology.

Peng Wang; Xin-He Meng

2004-06-21T23:59:59.000Z

157

Universality in Pure Gravity Mediation  

E-Print Network (OSTI)

If low energy supersymmetry is realized in nature, the apparent discovery of a Higgs boson with mass around 125 GeV points to a supersymmetric mass spectrum in the TeV or multi-TeV range. Multi-TeV scalar masses are a necessary component of supersymmetric models with pure gravity mediation or in any model with strong moduli stabilization. Here, we show that full scalar mass universality remains viable as long as the ratio of Higgs vevs, tan beta is relatively small (\\lesssim 2.5). We discuss in detail the low energy (observable) consequences of these models.

Jason L. Evans; Masahiro Ibe; Keith A. Olive; Tsutomu T. Yanagida

2013-02-21T23:59:59.000Z

158

Quantum Geometry and Quantum Gravity  

E-Print Network (OSTI)

The purpose of this contribution is to give an introduction to quantum geometry and loop quantum gravity for a wide audience of both physicists and mathematicians. From a physical point of view the emphasis will be on conceptual issues concerning the relationship of the formalism with other more traditional approaches inspired in the treatment of the fundamental interactions in the standard model. Mathematically I will pay special attention to functional analytic issues, the construction of the relevant Hilbert spaces and the definition and properties of geometric operators: areas and volumes.

J. Fernando Barbero G.

2008-04-23T23:59:59.000Z

159

Gravity monitoring of CO2 movement during sequestration: Model studies  

E-Print Network (OSTI)

right. Figure 14: Surface gravity response (?Gal) for theAbsolute and relative gravity integration for high precision2003, Seafloor Micro-gravity Survey of the Sleipner CO 2

Gasperikova, E.

2008-01-01T23:59:59.000Z

160

The Opening of the Tasman Sea: A Gravity Anomaly Animation  

Science Conference Proceedings (OSTI)

The first plate tectonic gravity anomaly grid animation using data from the Tasman Sea is presented. In this animation the tectonic elements are represented by their respective gravity fields, based on recent marine-satellite-derived gravity ...

C. Gaina; R. D. Müller; W. R. Roest; P. Symonds

1998-01-01T23:59:59.000Z

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While these samples are representative of the content of NLEBeta,
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161

American Journal  

NLE Websites -- All DOE Office Websites (Extended Search)

American American Journal of Science JUNE 2007 GENERALIZATION OF GAS HYDRATE DISTRIBUTION AND SATURATION IN MARINE SEDIMENTS BY SCALING OF THERMODYNAMIC AND TRANSPORT PROCESSES GAURAV BHATNAGAR*, WALTER G. CHAPMAN*, GERALD R. DICKENS**, BRANDON DUGAN**, and GEORGE J. HIRASAKI* † ABSTRACT. Gas hydrates dominated by methane naturally occur in deep marine sediment along continental margins. These compounds form in pore space between the seafloor and a sub-bottom depth where appropriate stability conditions prevail. However, the amount and distribution of gas hydrate within this zone, and free gas below, can vary significantly at different locations. To understand this variability, we develop a one-dimensional numerical model that simulates the accumulation of gas hydrates in marine sediments due to upward and downward fluxes of methane over time. The model contains rigorous

162

Gravity  

NLE Websites -- All DOE Office Websites (Extended Search)

das Farb-Kraftfeld, das entsteht, wenn sich das b Quark vom b Antiquark trennt, ignoriert. Diese Energie wandelt sich in ein weiteres Quark-Antiquark Paar um; was zur Emission...

163

Gravity  

NLE Websites -- All DOE Office Websites (Extended Search)

wissen zwar, wie man Gravitationskrfte berechnet, aber wir wissen nicht, wie man Gravitation in das mathematische Gebude der Quantentheorie des Standardmodells einbauen kann....

164

Gravity  

NLE Websites -- All DOE Office Websites (Extended Search)

Gravedad Avanzar Volver Principal ESTOY PERDIDO La fuerza gravitacional es quizs la fuerza ms familiar para nosotros, pero no est includa en el Modelo Standard, porque...

165

Gravity in Complex Hermitian Space-Time  

E-Print Network (OSTI)

A generalized theory unifying gravity with electromagnetism was proposed by Einstein in 1945. He considered a Hermitian metric on a real space-time. In this work we review Einstein's idea and generalize it further to consider gravity in a complex Hermitian space-time.

Ali H. Chamseddine

2006-10-09T23:59:59.000Z

166

Scale-Free Growing Networks and Gravity  

E-Print Network (OSTI)

We propose a possible relation between complex networks and gravity. Our guide in our proposal is the power-law distribution of the node degree in network theory and the information approach to gravity. The established bridge may allow us to carry geometric mathematical structures, which are considered in gravitational theories, to probabilistic aspects studied in the framework of complex networks and vice versa.

J. A. Nieto

2011-12-08T23:59:59.000Z

167

Ground Gravity Survey At Dixie Valley Geothermal Field Area ...  

Open Energy Info (EERE)

Details Location Dixie Valley Geothermal Field Area Exploration Technique Ground Gravity Survey Activity Date Usefulness useful DOE-funding Unknown Notes The gravity data are...

168

Ground Gravity Survey At Marysville Mt Area (Blackwell) | Open...  

Open Energy Info (EERE)

Ground Gravity Survey At Marysville Mt Area (Blackwell) Exploration Activity Details Location Marysville Mt Area Exploration Technique Ground Gravity Survey Activity Date...

169

Ground Gravity Survey At Valles Caldera - Sulphur Springs Area...  

Open Energy Info (EERE)

Gravity Survey Activity Date Usefulness not indicated DOE-funding Unknown Notes A computer program capable of two-dimensional modeling of gravity data was used in interpreting...

170

Ground Gravity Survey At Valles Caldera - Redondo Area (Wilt...  

Open Energy Info (EERE)

Gravity Survey Activity Date Usefulness not indicated DOE-funding Unknown Notes A computer program capable of two-dimensional modeling of gravity data was used in interpreting...

171

Mechanical Properties of Counter-gravity Cast IN718  

Science Conference Proceedings (OSTI)

Key Words: Counter-gravity, investment casting, superalloys, IN718, inert ... using the Counter-gravity Low-pressure Inert-atmosphere (CLI) investment casting ...

172

Ground Gravity Survey At Mcgee Mountain Area (DOE GTP) | Open...  

Open Energy Info (EERE)

Ground Gravity Survey At Mcgee Mountain Area (DOE GTP) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Mcgee Mountain...

173

Airborne Gravity Survey | Open Energy Information  

Open Energy Info (EERE)

Airborne Gravity Survey Airborne Gravity Survey Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Airborne Gravity Survey Details Activities (0) Areas (0) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Geophysical Techniques Exploration Sub Group: Gravity Techniques Parent Exploration Technique: Gravity Techniques Information Provided by Technique Lithology: Distribution of density in the subsurface enables inference of rock type. Stratigraphic/Structural: Delineation of steeply dipping formations, geological discontinuities and faults, intrusions and the deposition of silicates due to hydrothermal activity. Hydrological: Density of sedimentary rocks are strongly influenced by fluid contained within pore space. Dry bulk density refers to the rock with no moisture, while the wet bulk density accounts for water saturation; fluid content may alter density by up to 30%.(Sharma, 1997)

174

Definition: Ground Gravity Survey | Open Energy Information  

Open Energy Info (EERE)

Definition Definition Edit with form History Facebook icon Twitter icon » Definition: Ground Gravity Survey Jump to: navigation, search Dictionary.png Ground Gravity Survey The ground gravitational method is the study of the distribution of mass in the subsurface with the observation point at the earth's surface.[1] View on Wikipedia Wikipedia Definition A gravity anomaly is the difference between the observed acceleration of a planet's gravity and a value predicted from a model. A location with a positive anomaly exhibits more gravity than predicted, while a negative anomaly exhibits a lower value than predicted. References ↑ http://www.amazon.com/Geophysical-Field-Theory-Three-Volume-Gravitational/dp/0124020410 Ret Like Like You like this.Sign Up to see what your friends like.

175

Ground Gravity Survey | Open Energy Information  

Open Energy Info (EERE)

Ground Gravity Survey Ground Gravity Survey Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Ground Gravity Survey Details Activities (48) Areas (34) Regions (2) NEPA(2) Exploration Technique Information Exploration Group: Geophysical Techniques Exploration Sub Group: Gravity Techniques Parent Exploration Technique: Gravity Techniques Information Provided by Technique Lithology: Distribution of density in the subsurface enables inference of rock type. Stratigraphic/Structural: Delineation of steeply dipping formations, geological discontinuities and faults, intrusions and large-scale deposition of silicates due to hydrothermal activity. Hydrological: Density of sedimentary rocks are strongly influenced by fluid contained within pore space. Dry bulk density refers to the rock with no moisture, while the wet bulk density accounts for water saturation; fluid content may alter density by up to 30%.(Sharma, 1997)

176

Rainbow gravity and scale-invariant fluctuations  

E-Print Network (OSTI)

We re-examine a recently proposed scenario where the deformed dispersion relations associated with a flow of the spectral dimension to a UV value of 2 leads to a scale-invariant spectrum of cosmological fluctuations, without the need for inflation. In that scenario Einstein gravity was assumed. The theory displays a wavelength-dependent speed of light but by transforming to a suitable "rainbow frame" this feature can be removed, at the expense of modifying gravity. We find that the ensuing rainbow gravity theory is such that gravity switches off at high energy (or at least leads to a universal conformal coupling). This explains why the fluctuations are scale-invariant on all scales: there is no horizon scale as such. For dispersion relations that do not lead to exact scale invariance we find instead esoteric inflation in the rainbow frame. We argue that these results shed light on the behaviour of gravity under the phenomenon of dimensional reduction.

Giovanni Amelino-Camelia; Michele Arzano; Giulia Gubitosi; Joao Magueijo

2013-07-02T23:59:59.000Z

177

A new approach to quantum gravity  

E-Print Network (OSTI)

A new idea of quantum gravity is developed based on Gravitational Complementary Principle. This principle states that gravity has dual complement features: The quantum and classical aspects of gravity are complement and absolutely separated by the planck length into planckian and over-planckian domains, respectively. The classical Einstein equations are correct at the fundamental level at over-planckian domain and general relativity is not a low energy limit of a more fundamental theory. The quantum gravity is totally confined to the planckian domain with a new kind of ultra-short range interaction, mediated by massive (Planck mass) particles, through the virtual microscopic wormholes of the Planck scale with action ¯h. There is no room for gravitons or extra dimensions in ?e-mail:f.darabi@azaruniv.edu 1this scenario. It is shown that the hierarchy problem can solve the cosmological constant problem via this new quantum gravity. 2 1

F. Darabi

2008-01-01T23:59:59.000Z

178

Solar System constraints to nonminimally coupled gravity  

E-Print Network (OSTI)

We extend the analysis of Chiba, Smith and Erickcek \\cite{CSE} of Solar System constraints on $f(R)$ gravity to a class of nonminimally coupled (NMC) theories of gravity. These generalize $f(R)$ theories by replacing the action functional of General Relativity (GR) with a more general form involving two functions $f^1(R)$ and $f^2(R)$ of the Ricci scalar curvature $R$. While the function $f^1(R)$ is a nonlinear term in the action, analogous to $f(R)$ gravity, the function $f^2(R)$ yields a NMC between the matter Lagrangian density $\\LL_m$ and the scalar curvature. The developed method allows for obtaining constraints on the admissible classes of functions $f^1(R)$ and $f^2(R)$, by requiring that predictions of NMC gravity are compatible with Solar System tests of gravity. We apply this method to a NMC model which accounts for the observed accelerated expansion of the Universe.

Orfeu Bertolami; Riccardo March; Jorge Páramos

2013-06-05T23:59:59.000Z

179

Thermodynamics in Modified Gravity Theories  

E-Print Network (OSTI)

We demonstrate that there does exist an equilibrium description of thermodynamics on the apparent horizon in the expanding cosmological background for a wide class of modified gravity theories with the Lagrangian density $f(R, \\phi, X)$, where $R$ is the Ricci scalar and $X$ is the kinetic energy of a scalar field $\\phi$. This comes from a suitable definition of an energy momentum tensor of the "dark" component obeying the local energy conservation law in the Jordan frame. It is shown that the equilibrium description in terms of the horizon entropy $S$ is convenient because it takes into account the contribution of the horizon entropy $\\hat{S}$ in non-equilibrium thermodynamics as well as an entropy production term.

Kazuharu Bamba; Chao-Qiang Geng; Shinji Tsujikawa

2011-01-19T23:59:59.000Z

180

Non-Gaussian Stochastic Gravity  

E-Print Network (OSTI)

This paper presents a new, non-Gaussian formulation of stochastic gravity by incorporating the higher moments of the fluctuations of the quantum stress energy tensor for a free quantum scalar field in a consistent way. A scheme is developed for obtaining realizations of these fluctuations in terms of the Wightman function, and the behavior of the fluctuations is investigated. The resulting probability distribution for fluctuations of the energy density in Minkowski spacetime is found to be similar to a shifted Gamma distribution. This distribution features a minimum energy density cutoff at a small negative value, but a sharp peak in the vicinity of this cutoff such that the total probability of observing a negative value is approximately 62%, balanced by correspondingly larger but rarer positive values.

Jason D. Bates

2013-05-16T23:59:59.000Z

Note: This page contains sample records for the topic "gravity astm american" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Nonlinear Fluid Dynamics from Gravity  

E-Print Network (OSTI)

Black branes in AdS5 appear in a four parameter family labeled by their velocity and temperature. Promoting these parameters to Goldstone modes or collective coordinate fields -- arbitrary functions of the coordinates on the boundary of AdS5 -- we use Einstein's equations together with regularity requirements and boundary conditions to determine their dynamics. The resultant equations turn out to be those of boundary fluid dynamics, with specific values for fluid parameters. Our analysis is perturbative in the boundary derivative expansion but is valid for arbitrary amplitudes. Our work may be regarded as a derivation of the nonlinear equations of boundary fluid dynamics from gravity. As a concrete application we find an explicit expression for the expansion of this fluid stress tensor including terms up to second order in the derivative expansion.

Sayantani Bhattacharyya; Veronika E Hubeny; Shiraz Minwalla; Mukund Rangamani

2007-12-14T23:59:59.000Z

182

Exact Solutions in Massive Gravity  

E-Print Network (OSTI)

Massive gravity is a good theoretical laboratory to study modifications of General Relativity. The theory offers a concrete set-up to study models of dark energy, since it admits cosmological self-accelerating solutions in the vacuum, in which the size of the acceleration depends on the graviton mass. Moreover, non-linear gravitational self-interactions, in the proximity of a matter source, manage to mimic the predictions of linearised General Relativity, hence agreeing with solar-system precision measurements. In this article, we review our work in the subject, classifying, on one hand, static solutions, and on the other hand, self-accelerating backgrounds. For what respects static solutions we exhibit black hole configurations, together with other solutions that recover General Relativity near a source via the Vainshtein mechanism. For the self-accelerating solutions we describe a wide class of cosmological backgrounds, including an analysis of their stability.

Gianmassimo Tasinato; Kazuya Koyama; Gustavo Niz

2013-04-02T23:59:59.000Z

183

Emergent Horava gravity in graphene  

E-Print Network (OSTI)

First of all, we reconsider the tight - binding model of monolayer graphene, in which the variations of the hopping parameters are allowed. We demonstrate that the emergent 2D Weitzenbock geometry as well as the emergent U(1) gauge field appear. The emergent gauge field is equal to the linear combination of the components of the zweibein. Therefore, we actually deal with the gauge fixed version of the emergent 2+1 D teleparallel gravity. In particular, we work out the case, when the variations of the hopping parameters are due to the elastic deformations, and relate the elastic deformations with the emergent zweibein. Next, we investigate the tight - binding model with the varying intralayer hopping parameters for the multilayer graphene with the ABC stacking. In this case the emergent 2D Weitzenbock geometry and the emergent U(1) gauge field appear as well, the emergent low energy effective field theory has the anisotropic scaling.

G. E. Volovik; M. A. Zubkov

2013-05-20T23:59:59.000Z

184

Dark Energy and Modified Gravity  

E-Print Network (OSTI)

Explanations of the late-time cosmic acceleration within the framework of general relativity are plagued by difficulties. General relativistic models are mostly based on a dark energy field with fine-tuned, unnatural properties. There is a great variety of models, but all share one feature in common -- an inability to account for the gravitational properties of the vacuum energy, and a failure to solve the so-called coincidence problem. Two broad alternatives to dark energy have emerged as candidate models: these typically address only the coincidence problem and not the vacuum energy problem. The first is based on general relativity and attempts to describe the acceleration as an effect of inhomogeneity in the universe. If this alternative could be shown to work, then it would provide a dramatic resolution of the coincidence problem; however, a convincing demonstration of viability has not yet emerged. The second alternative is based on infra-red modifications to general relativity, leading to a weakening of gravity on the largest scales and thus to acceleration. Most examples investigated so far are scalar-tensor or brane-world models, and we focus on the simplest candidates of each type: $f(R)$ models and DGP models respectively. Both of these provide a new angle on the problem, but they also face serious difficulties. However, investigation of these models does lead to valuable insights into the properties of gravity and structure formation, and it also leads to new strategies for testing the validity of General Relativity itself on cosmological scales.

Ruth Durrer; Roy Maartens

2008-11-25T23:59:59.000Z

185

Generalised Wick Transform in Dimensionally Reduced Gravity  

E-Print Network (OSTI)

In the context of canonical quantum gravity, we study an alternative real quantisation scheme, which is arising by relating simpler Riemannian quantum theory to the more complicated physical Lorentzian theory - the generalised Wick transform. On the symmetry reduced models, homogenous Bianchi cosmology and 2+1 gravity, we investigate its generalised construction principle, demonstrate that the emerging quantum theory is equivalent to the one obtained from standard quantisation and how to obtain physical states in Lorentzian gravity from Wick transforming solutions of Riemannian quantum theory.

B. Hartmann; J. Wisniewski

2003-09-17T23:59:59.000Z

186

Dark Energy from Brane-world Gravity  

E-Print Network (OSTI)

Summary. Recent observations provide strong evidence that the universe is accelerating. This confronts theory with a severe challenge. Explanations of the acceleration within the framework of general relativity are plagued by difficulties. General relativistic models require a “dark energy ” field with effectively negative pressure. An alternative to dark energy is that gravity itself may behave differently from general relativity on the largest scales, in such a way as to produce acceleration. The alternative approach of modified gravity also faces severe difficulties, but does provide a new angle on the problem. This review considers an example of modified gravity, provided by brane-world models that self-accelerate at late times. 1 1

Roy Maartens

2006-01-01T23:59:59.000Z

187

Consistent matter couplings for Plebanski gravity  

SciTech Connect

We develop a scheme for the minimal coupling of all standard types of tensor and spinor field matter to Plebanski gravity. This theory is a geometric reformulation of vacuum general relativity in terms of two-form frames and connection one-forms, and provides a covariant basis for various quantization approaches. Using the spinor formalism we prove the consistency of the newly proposed matter coupling by demonstrating the full equivalence of Plebanski gravity plus matter to Einstein-Cartan gravity. As a by-product we also show the consistency of some previous suggestions for matter actions.

Tennie, Felix; Wohlfarth, Mattias N. R. [Zentrum fuer Mathematische Physik und II. Institut fuer Theoretische Physik, Universitaet Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany)

2010-11-15T23:59:59.000Z

188

Gravity as BF theory plus potential  

E-Print Network (OSTI)

Spin foam models of quantum gravity are based on Plebanski's formulation of general relativity as a constrained BF theory. We give an alternative formulation of gravity as BF theory plus a certain potential term for the B-field. When the potential is taken to be infinitely steep one recovers general relativity. For a generic potential the theory still describes gravity in that it propagates just two graviton polarizations. The arising class of theories is of the type amenable to spin foam quantization methods, and, we argue, may allow one to come to terms with renormalization in the spin foam context.

Kirill Krasnov

2009-07-23T23:59:59.000Z

189

Texas Gulf Coast Refinery District API Gravity (Weighted Average ...  

U.S. Energy Information Administration (EIA)

Texas Gulf Coast Refinery District API Gravity (Weighted Average) of Crude Oil Input to Refineries (Degree)

190

Ph.D.Thesis Binary inversion of gravity  

E-Print Network (OSTI)

Ph.D.Thesis Binary inversion of gravity data for salt imaging Richard A. Krahenbuhl Center for Gravity, Electrical & Magnetic Studies Colorado School of Mines Department of Geophysics Colorado School of gravity data for salt imaging Richard A. Krahenbuhl Center for Gravity, Electrical & Magnetic Studies

191

Texas Gulf Coast Refinery District API Gravity (Weighted ...  

U.S. Energy Information Administration (EIA)

Texas Gulf Coast Refinery District API Gravity (Weighted Average) of Crude Oil Input to Refineries (Degree)

192

Minimum Experimental Standards in the Laboratory Search for Gravity Effects  

Science Conference Proceedings (OSTI)

Peer?reviewed reports of experimental modifications of gravity over rotating superconductors (Podkletnov

H. Reiss; G. Hathaway

2006-01-01T23:59:59.000Z

193

Gravity and General Relativity at KCL D C Robinson  

E-Print Network (OSTI)

Gravity and General Relativity at KCL D C Robinson Mathematics Department King's College London Strand, London WC2R 2LS, UK. February 22, 2011 1 The study of gravity at KCL Research on gravity has been, an approach to New- tonian gravity similar to his field theory formulation of electromagnetism published

Bushnell, Colin J.

194

Gravity Recovery And Climate Experiment Hydrology, Earth Science and Climate  

E-Print Network (OSTI)

GRACE Gravity Recovery And Climate Experiment Hydrology, Earth Science and Climate Ole Baltazar of blood cell Delivers 10-Day / Monthly gravity field From 2002 Onwards Study gravity field changes | side 6 Range responds to Gravity #12;GRACE science results | 28. November 2007 | OA | side 7 Variations

Mosegaard, Klaus

195

Reduced Gravity Education Flight Opportunity for Students at Minority  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Reduced Gravity Education Flight Opportunity for Students at Reduced Gravity Education Flight Opportunity for Students at Minority Serving Institutions Reduced Gravity Education Flight Opportunity for Students at Minority Serving Institutions March 21, 2013 - 5:21pm Addthis Reduced Gravity Education Flight Opportunity for Students at Minority Serving Institutions NASA is offering undergraduate students from Minority Serving Institutions an opportunity to test experiments in microgravity aboard NASA's reduced gravity aircraft. This opportunity is a partnership between the Minority University Research and Education Program and NASA's Reduced Gravity Education Flight Program, which gives aspiring explorers a chance to propose, design and fabricate a reduced-gravity experiment. Selected teams will test and evaluate their

196

Reduced Gravity Education Flight Opportunity for Students at Minority  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Reduced Gravity Education Flight Opportunity for Students at Reduced Gravity Education Flight Opportunity for Students at Minority Serving Institutions Reduced Gravity Education Flight Opportunity for Students at Minority Serving Institutions March 21, 2013 - 5:21pm Addthis Reduced Gravity Education Flight Opportunity for Students at Minority Serving Institutions NASA is offering undergraduate students from Minority Serving Institutions an opportunity to test experiments in microgravity aboard NASA's reduced gravity aircraft. This opportunity is a partnership between the Minority University Research and Education Program and NASA's Reduced Gravity Education Flight Program, which gives aspiring explorers a chance to propose, design and fabricate a reduced-gravity experiment. Selected teams will test and evaluate their

197

Gravity Waves in a Horizontal Shear Flow. Part II: Interaction between Gravity Waves and Potential Vorticity Perturbations  

E-Print Network (OSTI)

Gravity Waves in a Horizontal Shear Flow. Part II: Interaction between Gravity Waves and Potential perturbations and propagating internal gravity waves in a horizon- tally sheared zonal flow is investigated. In the strong stratification limit, an initial vorticity perturbation weakly excites two propagating gravity

Farrell, Brian F.

198

Observations of a Mesoscale Ducted Gravity Wave  

Science Conference Proceedings (OSTI)

This paper reports coordinated observations of a mesoscale gravity wave made during the FRONTS 84 field experiment conducted in southwestern France in the summer of 1984. The observations were unique in the sense that all relevant wave ...

F. M. Ralph; V. Venkateswaran; M. Crochet

1993-10-01T23:59:59.000Z

199

Filtering of Gravity Modes in Atmospheric Models  

Science Conference Proceedings (OSTI)

The impact of gravity modes in atmospheric model predictions is assessed quantitatively by comparing integrations with a normal mode initialized primitive equation model and its corresponding pseudogeostrophic form to document some generally ...

F. Baer; J. J. Tribbia

1984-05-01T23:59:59.000Z

200

Stochastic Parameterization of Gravity Wave Stresses  

Science Conference Proceedings (OSTI)

Selective transmission of gravity waves into the upper mesosphere and lower thermosphere leads to the generation of mean flows opposite to those below. This interaction is addressed in the context of a simplified transient, stochastic, ...

Timothy J. Dunkerton

1982-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "gravity astm american" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Generation of Turbulence by Atmospheric Gravity Waves  

Science Conference Proceedings (OSTI)

The standard current criterion for the generation of turbulence by atmospheric gravity waves and for the associated limitation on wave growth is based upon the standard criterion for static instability of the unperturbed atmosphere, namely, that ...

Colin O. Hines

1988-04-01T23:59:59.000Z

202

Effect of Nonlinearity on Atmospheric Gravity Waves  

Science Conference Proceedings (OSTI)

The weakly nonlinear limit of two-dimensional gravity waves in an incompressible, inviscid and stably stratified atmosphere is studied. The three-wave resonant interaction theory indicates an energy cascade from a vertically propagating wave (...

Mostafa M. Ibrahim

1987-02-01T23:59:59.000Z

203

Inertia–Gravity Waves in the Stratosphere  

Science Conference Proceedings (OSTI)

The propagation and refraction of stationary inertia–gravity waves in the winter stratosphere is examined with ray tracing. Due to their smaller vertical group velocity these waves experience more lateral ray movement and horizontal refraction ...

Timothy J. Dunkerton

1984-12-01T23:59:59.000Z

204

Definition: Gravity Techniques | Open Energy Information  

Open Energy Info (EERE)

0521576326 Ret LikeLike UnlikeLike You like this.Sign Up to see what your friends like. rieved from "http:en.openei.orgwindex.php?titleDefinition:GravityTechniques&oldid598...

205

Quantum gravity and renormalization: The tensor track  

SciTech Connect

We propose a new program to quantize and renormalize gravity based on recent progress on the analysis of large random tensors. We compare it briefly with other existing approaches.

Rivasseau, Vincent [Laboratoire de Physique Theorique, CNRS UMR 8627 Universite Paris-Sud, 91405 Orsay (France)

2012-06-27T23:59:59.000Z

206

Energy conditions in f(R)-gravity  

E-Print Network (OSTI)

In order to shed some light on the current discussion about f(R)-gravity theories we derive and discuss the bounds imposed by the energy conditions on a general f(R) functional form. The null and strong energy conditions in this framework are derived from the Raychaudhuri's equation along with the requirement that gravity is attractive, whereas the weak and dominant energy conditions are stated from a comparison with the energy conditions that can be obtained in a direct approach via an effective energy-momentum tensor for f(R)-gravity. As a concrete application of the energy conditions to locally homogeneous and isotropic f(R)-cosmology, the recent estimated values of the deceleration and jerk parameters are used to examine the bounds from the weak energy condition on the parameters of two families of f(R)-gravity theories.

Santos, J; Rebouças, M J; Carvalho, F C

2007-01-01T23:59:59.000Z

207

Energy and Hamiltonian in first order gravity  

E-Print Network (OSTI)

In this work the definition of a quasilocal energy for four dimensional first order gravity is developed. Using this an action principle which is adequate for the canonical ensemble is obtained. The microcanonical action principle is obtained as well.

Rodrigo Aros

2005-04-29T23:59:59.000Z

208

Probes of strong-field gravity  

E-Print Network (OSTI)

In this thesis, I investigate several ways to probe gravity in the strong-field regime. These investigations focus on observables from the gravitational dynamics, i.e. when time derivatives are large: thus I focus on sources ...

Stein, Leo Chaim

2012-01-01T23:59:59.000Z

209

Observationally Verifiable Predictions of Modified Gravity  

Science Conference Proceedings (OSTI)

MOG is a fully relativistic modified theory of gravity based on an action principle. The MOG field equations are exactly solvable numerically in two important cases. In the spherically symmetric

J. W. Moffat; V. T. Toth

2010-01-01T23:59:59.000Z

210

SUSY QM meets 5d Gravity  

E-Print Network (OSTI)

We report hidden quantum mechanical supersymmetry structure in five-dimensional gravity with the Randall-Sundrum background. We show that two N=2 supersymmetries are hidden in the spectrum.

Ohya, Satoshi

2010-01-01T23:59:59.000Z

211

Dynamical Foundations of the Brane Induced Gravity  

E-Print Network (OSTI)

We present a comprehensive formalism to derive precise expressions for the induced gravity of the braneworld, assuming the dynamics of the Dirac-Nambu-Goto type. The quantum fluctuations of the brane at short distances give rise to divergences, which should be cutoff at the scale of the inverse thickness of the brane. It turns out that the induced-metric formula is converted into an Einstein-like equation via the quantum effects. We determine the coefficients of the induced cosmological and gravity terms, as well as those of the terms including the extrinsic curvature and the normal connection gauge field. The latter is the characteristic of the brane induced gravity theory, distinguished from ordinary none-brane induced gravity.

Keiichi Akama; Takashi Hattori

2013-09-12T23:59:59.000Z

212

Shear Excitation of Atmospheric Gravity Waves  

Science Conference Proceedings (OSTI)

Unstable Velocity shears are a Common source of vertically propagating gravity waves in the atmosphere. However, the growth rates of unstable modes predicted by linear theory cannot always amount for their observed importance.

David C. Fritts

1982-09-01T23:59:59.000Z

213

Earthlings : humanity's essential relationship with gravity  

E-Print Network (OSTI)

A realm of serious scientific questions about gravity's role in biology is being researched in labs around the world, from NASA's Dryden Research Laboratories in the Mohave Desert, to Japan's Radioisotope Center at the ...

Vargas Medina, Iris Mónica

2009-01-01T23:59:59.000Z

214

Energy conditions in f(R)-gravity  

E-Print Network (OSTI)

In order to shed some light on the current discussion about f(R)-gravity theories we derive and discuss the bounds imposed by the energy conditions on a general f(R) functional form. The null and strong energy conditions in this framework are derived from the Raychaudhuri's equation along with the requirement that gravity is attractive, whereas the weak and dominant energy conditions are stated from a comparison with the energy conditions that can be obtained in a direct approach via an effective energy-momentum tensor for f(R)-gravity. As a concrete application of the energy conditions to locally homogeneous and isotropic f(R)-cosmology, the recent estimated values of the deceleration and jerk parameters are used to examine the bounds from the weak energy condition on the parameters of two families of f(R)-gravity theories.

J. Santos; J. S. Alcaniz; M. J. Reboucas; F. C. Carvalho

2007-08-02T23:59:59.000Z

215

Internal Gravity Wave Generation and Hydrodynamic Instability  

Science Conference Proceedings (OSTI)

Two mechanisms are proposed whereby internal gravity waves (IGW) may radiate from a linearly unstable region of Boussinesq parallel flow that is characterized in the far field by constant horizontal velocity and Brunt-Väisälä frequency. Through ...

B. R. Sutherland; C. P. Caulfield; W. R. Peltier

1994-11-01T23:59:59.000Z

216

Finite temperature R-squared quantum gravity  

E-Print Network (OSTI)

The quantum gravity path integral's measure can be written as the product of classical backgrounds and quantum fluctuations about each background. After proving that fluctuations about the background do not diffuse in Hilbert space and obey the laws of many-body statistics, their probability distributions, entropy, and expected background are determined. This background obeys expectation-valued Einstein equations and features an entropy-based positive cosmological constant. From the fluctuation probability distributions, a finite temperature, R-squared, quantum gravity path integral is constructed whose action presents an interaction picture of quantum gravity that `moves with' the expected background in Hilbert space. Within this interaction picture of quantum fluctuations about an expected background, the fields required to describe quantum gravity have been transformed into `ordinary' quantum fields propagating on this `rigid' or `fixed' expected background. Back-reaction has been fully accounted for, and the quantum formulation is manifestly background independent.

C. D. Burton

2013-02-07T23:59:59.000Z

217

Towards Gravity-Gauge-Higgs Unification  

E-Print Network (OSTI)

We discuss a possibility to solve the gauge hierarchy problem in the framework of Gravity-Gauge-Higgs Unification scenario. We have calculated 1-loop correction to the mass of the scalar field, which is originated from 55-component of the metric, in five dimensional gravity theory with the bulk scalar field compactified on S^1. It is shown that the quadratic divergences are canceled and the finite mass is generated by explicit diagrammatic calculations and the effective potential calculations.

K. Hasegawa; C. S. Lim; Nobuhito Maru

2004-08-24T23:59:59.000Z

218

Localizing gravity on exotic thick 3-branes  

Science Conference Proceedings (OSTI)

We consider localization of gravity on thick branes with a nontrivial structure. Double walls that generalize the thick Randall-Sundrum solution, and asymmetric walls that arise from a Z{sub 2} symmetric scalar potential, are considered. We present a new asymmetric solution: a thick brane interpolating between two AdS{sub 5} spacetimes with different cosmological constants, which can be derived from a 'fake supergravity' superpotential, and show that it is possible to confine gravity on such branes.

Castillo-Felisola, Oscar [Centro de Fisica Fundamental, Universidad de Los Andes, Merida (Venezuela); International Centre for Theoretical Physics, 34100 Trieste (Italy); Melfo, Alejandra; Pantoja, Nelson; Ramirez, Alba [Centro de Fisica Fundamental, Universidad de Los Andes, Merida (Venezuela)

2004-11-15T23:59:59.000Z

219

Thermodynamics of space quanta models quantum gravity  

E-Print Network (OSTI)

Canonically quantized 3+1 general relativity with the global one dimensionality (1D) conjecture defines the model, which dimensionally reduced and secondary quantized yields the 1D quantum field theory wherein generic one-point correlations create physical scales. This simple quantum gravity model, however, can be developed in a wider sense. In this paper we propose to consider ab initio thermodynamics of space quanta as the quantum gravity phenomenology. The thermodynamics is constructed in the entropic formalism.

L. A. Glinka

2009-06-20T23:59:59.000Z

220

Locating American Manufacturing:  

Science Conference Proceedings (OSTI)

... future of manufacturing in America but also ... as defined in the North American Industry Classification ... about two thirds of American metropolitan areas ...

2013-07-31T23:59:59.000Z

Note: This page contains sample records for the topic "gravity astm american" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

American Samoa Profile  

U.S. Energy Information Administration (EIA)

American Samoa Quick Facts. American Samoa is nearly 100 percent dependent on imported fossil fuels, including diesel fuel for its electric power ...

222

Assessing Hypothetical Gravity Control Propulsion  

E-Print Network (OSTI)

Gauging the benefits of hypothetical gravity control propulsion is difficult, but addressable. The major challenge is that such breakthroughs are still only notional concepts rather than being specific methods from which performance can be rigorously quantified. A recent assessment by Tajmar and Bertolami used the rocket equation to correct naive misconceptions, but a more fundamental analysis requires the use of energy as the basis for comparison. The energy of a rocket is compared to an idealized space drive for the following cases: Earth-to-orbit, interstellar transit, and levitation. The space drive uses 3.6 times less energy for Earth to orbit. For deep space travel, space drive energy scales as the square of delta-v, while rocket energy scales exponentially. This has the effect of rendering a space drive 150-orders-of-magnitude better than a 17,000-sec Specific Impulse rocket for sending a modest 5000 kg probe to traverse 5 light-years in 50 years. Indefinite levitation, which is impossible for a rocket, could conceivably require 62 MJ/kg for a space drive. Assumption sensitivities and further analysis options are listed to guide further inquires.

Marc G. Millis

2006-03-14T23:59:59.000Z

223

Quantum gravity and inventory accumulation  

E-Print Network (OSTI)

We begin by studying inventory accumulation at a LIFO (last-in-first-out) retailer with two products. In the simplest version, the following occur with equal probability at each time step: first product ordered, first product produced, second product ordered, second product produced. The inventory thus evolves as a simple random walk on Z^2. In more interesting versions, a p fraction of customers orders the "freshest available" product regardless of type. We show that the corresponding random walks scale to Brownian motions with diffusion matrices depending on p. We then turn our attention to the critical Fortuin-Kastelyn random planar map model, which gives, for each q>0, a probability measure on random (discretized) two-dimensional surfaces decorated by loops, related to the q-state Potts model. A longstanding open problem is to show that as the discretization gets finer, the surfaces converge in law to a limiting (loop-decorated) random surface. The limit is expected to be a Liouville quantum gravity surface decorated by a conformal loop ensemble, with parameters depending on q. Thanks to a bijection between decorated planar maps and inventory trajectories (closely related to bijections of Bernardi and Mullin), our results about the latter imply convergence of the former in a particular topology. A phase transition occurs at p = 1/2, q=4.

Scott Sheffield

2011-08-10T23:59:59.000Z

224

Scattering in Topologically Massive Gravity, Chiral Gravity and the corresponding Anyon-Anyon Potential Energy  

E-Print Network (OSTI)

We compute the tree-level scattering amplitude between two covariantly conserved sources in generic Cosmological Topologically Massive Gravity augmented with a Fierz-Pauli term that has three massive degrees of freedom. We consider the Chiral Gravity limit in the anti-de Sitter space as well as the limit of Flat-Space Chiral Gravity. We show that Chiral Gravity cannot be unitarily deformed with a Fierz-Pauli mass. We calculate the non-relativistic potential energy between two point-like spinning sources. In addition to the expected mass-mass and spin-spin interactions, there are mass-spin interactions due to the presence of the gravitational Chern-Simons term which induces spin for any massive object and turns it to an anyon. We also show that the tree-level scattering is trivial for the Flat-Space Chiral Gravity.

Dengiz, Suat; Tekin, Bayram

2013-01-01T23:59:59.000Z

225

Gravity model studies of Newberry Volcano, Oregon  

SciTech Connect

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

Gettings, M.E.; Griscom, A.

1988-09-10T23:59:59.000Z

226

GRAVITY DARKENING AND BRIGHTENING IN BINARIES  

SciTech Connect

We apply a von Zeipel gravity darkening model to corotating binaries to obtain a simple, analytical expression for the emergent radiative flux from a tidally distorted primary orbiting a point-mass secondary. We adopt a simple Roche model to determine the envelope structure of the primary, assumed massive and centrally condensed, and use the results to calculate the flux. As for single rotating stars, gravity darkening reduces the flux along the stellar equator of the primary, but, unlike for rotating stars, we find that gravity brightening enhances the flux in a region around the stellar poles. We identify a critical limiting separation beyond which hydrostatic equilibrium no longer is possible, whereby the flux vanishes at the point on the stellar equator of the primary facing the companion. For equal-mass binaries, the total luminosity is reduced by about 13% when this limiting separation is reached.

White, Helen E.; Baumgarte, Thomas W. [Department of Physics and Astronomy, Bowdoin College, Brunswick, ME 04011 (United States); Shapiro, Stuart L. [Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States)

2012-06-20T23:59:59.000Z

227

Quantum gravity effects in the Kerr spacetime  

Science Conference Proceedings (OSTI)

We analyze the impact of the leading quantum gravity effects on the properties of black holes with nonzero angular momentum by performing a suitable renormalization group improvement of the classical Kerr metric within quantum Einstein gravity. In particular, we explore the structure of the horizons, the ergosphere, and the static limit surfaces as well as the phase space available for the Penrose process. The positivity properties of the effective vacuum energy-momentum tensor are also discussed and the 'dressing' of the black hole's mass and angular momentum are investigated by computing the corresponding Komar integrals. The pertinent Smarr formula turns out to retain its classical form. As for their thermodynamical properties, a modified first law of black-hole thermodynamics is found to be satisfied by the improved black holes (to second order in the angular momentum); the corresponding Bekenstein-Hawking temperature is not proportional to the surface gravity.

Reuter, M. [Institute of Physics, University of Mainz, Staudingerweg 7, D-55099 Mainz (Germany); Tuiran, E. [Departamento de Fisica, Universidad del Norte, Km 5 via a Puerto Colombia, AA-1569 Barranquilla (Colombia)

2011-02-15T23:59:59.000Z

228

Problems with Mannheim's conformal gravity program  

E-Print Network (OSTI)

We show that Mannheim's conformal gravity program, whose potential has a term proportional to $1/r$ and another term proportional to $r$, does not reduce to Newtonian gravity at short distances, unless one assumes undesirable singularities of the mass density of the proton. Therefore, despite the claim that it successfully explains galaxy rotation curves, unless one assumes the singularities, it seems to be falsified by numerous Cavendish-type experiments performed at laboratories on Earth whose work have not found any deviations from Newton's theory. Moreover, it can be shown that as long as the total mass of the proton is positive, Mannheim's conformal gravity program leads to negative linear potential, which is problematic from the point of view of fitting galaxy rotation curves, which necessarily requires positive linear potential.

Youngsub Yoon

2013-05-01T23:59:59.000Z

229

Energy Distribution in f(R) Gravity  

E-Print Network (OSTI)

The well-known energy problem is discussed in f(R) theory of gravity. We use the generalized Landau-Lifshitz energy-momentum complex in the framework of metric f(R) gravity to evaluate the energy density of plane symmetric solutions for some general f(R) models. In particular, this quantity is found for some popular choices of f(R) models. The constant scalar curvature condition and the stability condition for these models are also discussed. Further, we investigate the energy distribution of cosmic string spacetime.

Sharif, M

2009-01-01T23:59:59.000Z

230

Energy Distribution in f(R) Gravity  

E-Print Network (OSTI)

The well-known energy problem is discussed in f(R) theory of gravity. We use the generalized Landau-Lifshitz energy-momentum complex in the framework of metric f(R) gravity to evaluate the energy density of plane symmetric solutions for some general f(R) models. In particular, this quantity is found for some popular choices of f(R) models. The constant scalar curvature condition and the stability condition for these models are also discussed. Further, we investigate the energy distribution of cosmic string spacetime.

M. Sharif; M. Farasat Shamir

2009-12-18T23:59:59.000Z

231

Gravity waves from vortex dipoles and jets  

E-Print Network (OSTI)

The dissertation first investigates gravity wave generation and propagation from jets within idealized vortex dipoles using a nonhydrostatic mesoscale model. Several initially balanced and localized jets induced by vortex dipoles are examined here. Within these dipoles, inertia-gravity waves with intrinsic frequencies 1-2 times the Coriolis parameter are simulated in the jet exit region. The ray tracing analysis reveals strong variation of wave characteristics along ray paths. The dependence of wave amplitude on the Rossby number is examined through experiments in which the two vortices are initially separated by a large distance but subsequently approach each other and form a vortex dipole with an associated amplifying localized jet. The amplitude of stationary gravity waves in the simulations with a 90-km grid spacing increases nearly linearly with the square of the Rossby number but significantly more rapidly when smaller grid spacing is used. To further address the source mechanism of the gravity waves within the vortex dipole, a linear numerical framework is developed based on the framework proposed by Plougonven and Zhang (2007). Using the nonlinearly balanced fields as the basic state and driven by three types of large scale forcing, the vorticity, divergence and thermodynamic forcing, this linear model is utilized to obtain linear wave responses. The wave packets in the linear responses compare reasonably well with the MM5 simulated gravity waves. It is suggested that the vorticity forcing is the leading contribution to both gravity waves in the jet exit region and the ascent/descent feature in the jet core. This linear model is also adopted to study inertia-gravity waves in the vicinity of a baroclinic jet during the life cycle of an idealized baroclinic wave. It is found that the thermodynamic forcing and the vorticity forcing are equally important to the gravity waves in the low stratosphere, but the divergence forcing is again playing a lesser role. Two groups of wave packets are present in the linear responses; their sources appear to locate either near the surface front or near the middle/upper tropospheric jet.

Wang, Shuguang

2008-08-01T23:59:59.000Z

232

Proper Time Flow Equation for Gravity  

E-Print Network (OSTI)

We analyze a proper time renormalization group equation for Quantum Einstein Gravity in the Einstein-Hilbert truncation and compare its predictions to those of the conceptually different exact renormalization group equation of the effective average action. We employ a smooth infrared regulator of a special type which is known to give rise to extremely precise critical exponents in scalar theories. We find perfect consistency between the proper time and the average action renormalization group equations. In particular the proper time equation, too, predicts the existence of a non-Gaussian fixed point as it is necessary for the conjectured nonperturbative renormalizability of Quantum Einstein Gravity.

Bonanno, A

2005-01-01T23:59:59.000Z

233

Linear Stratospheric Gravity Waves above Convective Thermal Forcing  

Science Conference Proceedings (OSTI)

The spectra of linear gravity waves generated by a time-varying tropospheric thermal forcing representing organized convection are compared to the spectra of stratospheric gravity waves generated by organized convection in a fully nonlinear two-...

Rajul E. Pandya; M. Joan Alexander

1999-07-01T23:59:59.000Z

234

Coupling between Gravity Waves and Tropical Convection at Mesoscales  

Science Conference Proceedings (OSTI)

An idealized cloud-system-resolving model simulation is used to examine the coupling between a tropical cloud population and the mesoscale gravity waves that it generates. Spectral analyses of the cloud and gravity wave fields identify a clear ...

Todd P. Lane; Fuqing Zhang

2011-11-01T23:59:59.000Z

235

New Gravity Wave Treatments for GISS Climate Models  

Science Conference Proceedings (OSTI)

Previous versions of GISS climate models have either used formulations of Rayleigh drag to represent unresolved gravity wave interactions with the model-resolved flow or have included a rather complicated treatment of unresolved gravity waves that,...

Marvin A. Geller; Tiehan Zhou; Reto Ruedy; Igor Aleinov; Larissa Nazarenko; Nikolai L. Tausnev; Shan Sun; Maxwell Kelley; Ye Cheng

2011-08-01T23:59:59.000Z

236

Influence of Gravity Waves in the Tropical Upwelling: WACCM Simulations  

Science Conference Proceedings (OSTI)

The annual cycle of tropical upwelling and contributions by planetary and gravity waves are investigated from climatological simulations using the Whole Atmosphere Community Climate Model (WACCM) including three gravity wave drag (GWD) ...

Hye-Yeong Chun; Young-Ha Kim; Hyun-Joo Choi; Jung-Yoon Kim

2011-11-01T23:59:59.000Z

237

Mobility Characterization of Planetary Rover in Reduced Gravity Environment  

Science Conference Proceedings (OSTI)

This paper describes effects of gravity on mobility performance of wheeled rovers for future lunar/planetary exploration missions. A series of model tests of a wheel?terrain system were performed on an aircraft during variable gravity maneuvers

Taizo Kobayashi; Hidetoshi Ochiai; Junya Yamakawa; Shigeru Aoki; Kai Matsui; Akira Miyahara

2008-01-01T23:59:59.000Z

238

Correlation Between Precision Gravity and Subsidence Measurements at Cerro Prieto  

E-Print Network (OSTI)

PRECISION GRAVITY AND SUBSIDENCE MEASUREMENTS AT CERROPRECISION GRAVITY AND SUBSIDENCE MEASUREMENTS AT CERROn d i c a t e s t h a t subsidence took place. Uost of t h e

Zelwer, R.

2010-01-01T23:59:59.000Z

239

An Ultrasimple Spectral Parameterization for Nonorographic Gravity Waves  

Science Conference Proceedings (OSTI)

This paper describes a new computationally efficient, ultrasimple nonorographic spectral gravity wave parameterization model. Its predictions compare favorably, though not perfectly, with a model of gravity wave propagation and breaking that ...

C. D. Warner; M. E. McIntyre

2001-07-01T23:59:59.000Z

240

Numerical Study of Gravity Currents in a Channel  

Science Conference Proceedings (OSTI)

A three-dimensional primitive-equation model was used to study gravity currents produced by instantaneous releases of a buoyant fluid in a rectangular channel. Without rotation, the gravity current passes through two distinct phases: an initial ...

Dong-Ping Wang

1985-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "gravity astm american" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Quantum gravity as a group field theory: a sketch  

E-Print Network (OSTI)

We give a very brief introduction to the group field theory approach to quantum gravity, a generalisation of matrix models for 2-dimensional quantum gravity to higher dimension, that has emerged recently from research in spin foam models.

Daniele Oriti

2005-12-07T23:59:59.000Z

242

Linear Spectral Numerical Model for Internal Gravity Wave Propagation  

Science Conference Proceedings (OSTI)

A three-dimensional linear spectral numerical model is proposed to simulate the propagation of internal gravity wave fluctuations in a stably stratified atmosphere. The model is developed to get first-order estimations of gravity wave ...

J. Marty; F. Dalaudier

2010-05-01T23:59:59.000Z

243

An Unusually Strong Gravity Wave over Western Washington  

Science Conference Proceedings (OSTI)

A mesoscale wave disturbance, observed over western Washington State, is studied through local observations and recognized by comparisons with theory as a large-amplitude gravity wave. It is shown that this gravity wave propagated over 200 km in ...

Bruce H. Bauck

1992-06-01T23:59:59.000Z

244

U.S. Percent Total Imported by API Gravity of Crude ...  

U.S. Energy Information Administration (EIA)

Referring Pages: Percentages of Total Imported Crude Oil by API Gravity; Percentages of Total Imported Crude Oil by API Gravity

245

Rapid gravity and gravity gradiometry terrain correction via adaptive quadtree mesh discretization Kristofer Davis, M. Andy Kass, and Yaoguo Li, Center for Gravity, Electrical and Magnetic Studies, Colorado School  

E-Print Network (OSTI)

Rapid gravity and gravity gradiometry terrain correction via adaptive quadtree mesh discretization Kristofer Davis, M. Andy Kass, and Yaoguo Li, Center for Gravity, Electrical and Magnetic Studies, Colorado School of Mines SUMMARY We present a method for modeling the terrain response in gravity and gravity

246

Hypothetical Gravity Control and Implications for Spacecraft Propulsion  

E-Print Network (OSTI)

A scientific analysis of the conditions under which gravity could be controlled and the implications that an hypothetical manipulation of gravity would have for known schemes of space propulsion have been the scope of a recent study carried out for the European Space Agency. The underlying fundamental physical principles of known theories of gravity were analysed and shown that even if gravity could be modified it would bring somewhat modest gains in terms of launching of spacecraft and no breakthrough for space propulsion.

O. Bertolami; M. Tajmar

2002-07-31T23:59:59.000Z

247

Ground Gravity Survey At Blue Mountain Area (Fairbank Engineering...  

Open Energy Info (EERE)

to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Blue Mountain Area (Fairbank Engineering, 2006) Exploration Activity...

248

Exact solutions with noncommutative symmetries in Einstein and gauge gravity  

Science Conference Proceedings (OSTI)

We present new classes of exact solutions with noncommutative symmetries constructed in vacuum Einstein gravity (in general

Sergiu I. Vacaru

2005-01-01T23:59:59.000Z

249

Materials Science in Reduced Gravity - Programmaster.org  

Science Conference Proceedings (OSTI)

Jul 31, 2012 ... About this Symposium. Meeting, 2013 TMS Annual Meeting & Exhibition. Symposium, Materials Science in Reduced Gravity. Sponsorship ...

250

Gravity and Yang?Mills Fields: Geometrical Approaches  

Science Conference Proceedings (OSTI)

A new geometrical framework for a tetrad?affine formulation of gravity coupled with Yang?Mills fields is proposed.

Roberto Cianci; Stefano Vignolo

2005-01-01T23:59:59.000Z

251

Gravity Waves in Shear and Implications for Organized Convection  

E-Print Network (OSTI)

Gravity Waves in Shear and Implications for Organized Convection Samuel N. Stechmann Department, Los Angeles, CA 90095­1555. E-mail: stechmann@math.ucla.edu #12;ABSTRACT It is known that gravity, the gravity waves can create a more favorable environment on one side of preexisting convection than the other

Stechmann, Samuel N.

252

Tomo-gravity How to ComputeHow to Compute  

E-Print Network (OSTI)

Tomo-gravity How to ComputeHow to Compute Accurate Traffic Matrices forAccurate Traffic MatricesStanford Shannon LabShannon Lab #12;Tomo-gravity Want to know demands from source to destination ProblemProblem Have link traffic measurements (from SNMP) A B C #12;Tomo-gravity Example App: reliability analysis

Roughan, Matthew

253

Gravity Load Collapse of Building Frames during Earthquakes  

E-Print Network (OSTI)

Gravity Load Collapse of Building Frames during Earthquakes J. P. Moehle, K. J. Elwood, H. Sezen to frames designed primarily for gravity loads. Columns generally were not designed to have strengths capacity of the column. As the axial capacity diminishes, the gravity loads carried by the column must

Sezen, Halil

254

Gravity currents in two-layer stratified media  

E-Print Network (OSTI)

Gravity currents in two-layer stratified media Morris R. Flynn & Alan W.Tan Dept. of Mechanical Engineering, U.Alberta Funding: NSERC #12;· Gravity currents appear over a broad range of time/length scales. (1999), Flynn & Linden (2006),White & Helfrich (2008), Ungarish (2009) Introduction current gravity

Flynn, Morris R.

255

Gravity Surface Wave Bifurcation in a Highly Turbulent Swirling Flow  

E-Print Network (OSTI)

Gravity Surface Wave Bifurcation in a Highly Turbulent Swirling Flow Michael Baumer University Gravity Wave 2 3 Measurements 3 4 Mechanical Hardware: Problems and Solutions 5 5 Results 7 6 Conclusions investigated a free-surface gravity wave bifurcation in the large-separation regime, that is, where

Witten, Thomas A.

256

Gravity waves excited by jets: Propagation versus generation R. Plougonven  

E-Print Network (OSTI)

Gravity waves excited by jets: Propagation versus generation R. Plougonven School of Mathematics September 2005. [1] Atmospheric jets are known to be an important source of inertia-gravity waves, yet mechanisms for the gravity waves, with the underlying assumption that the characteristics of the waves were

Plougonven, Riwal

257

American Samoa: Energy Resources | Open Energy Information  

Open Energy Info (EERE)

territory of the United States.1 Energy Incentives for American Samoa American Samoa - Net Metering (American Samoa) Utility Companies in American Samoa American Samoa Power...

258

Effects of Nonlinearity on Convectively Forced Internal Gravity Waves: Application to a Gravity Wave Drag Parameterization  

Science Conference Proceedings (OSTI)

In the present study, the authors propose a way to include a nonlinear forcing effect on the momentum flux spectrum of convectively forced internal gravity waves using a nondimensional numerical model (NDM) in a two-dimensional framework. In NDM, ...

Hye-Yeong Chun; Hyun-Joo Choi; In-Sun Song

2008-02-01T23:59:59.000Z

259

Convective Generation of Gravity Waves in Venus's Atmosphere: Gravity Wave Spectrum and Momentum Transport  

Science Conference Proceedings (OSTI)

The emission of internal gravity waves from a layer of dry convection embedded within a stable atmosphere with static stability and zonal winds varying in height is calculated. This theory is applied to Venus to investigate whether these waves ...

Stephen S. Leroy; Andrew P. Ingersoll

1995-11-01T23:59:59.000Z

260

The Mars Gravity Biosatellite as an innovative partial gravity research platform  

E-Print Network (OSTI)

The Mars Gravity Biosatellite is an unprecedented independent spaceflight platform for gravitational biology research. With a projected first launch after 2010, the low Earth orbit satellite will support a cohort of fifteen ...

Fulford-Jones, Thaddeus R. F

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gravity astm american" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Improvement of Orographic Gravity Wave Parameterization Using a Mesoscale Gravity Wave Model  

Science Conference Proceedings (OSTI)

Parameterization of gravity waves due to subgrid-scale orography is now included in most existing large-scale models of the atmosphere. Parameterization schemes, however, have so far been evaluated mainly in view of the overall performance of the ...

Young-Joon Kim; Akio Arakawa

1995-06-01T23:59:59.000Z

262

Atmospheric Gravity Waves and Aircraft Turbulence Encounters  

Science Conference Proceedings (OSTI)

We describe aircraft turbulence-atmospheric gravity wave events which occurred during a 2-day period over the Continental Divide. The waves are observed by two microbarograph networks an each side of the divide and last for several hours at a ...

A. J. Bedard Jr.; F. Canavero; F. Einaudi

1986-12-01T23:59:59.000Z

263

High energy scattering in gravity and supergravity  

E-Print Network (OSTI)

We investigate features of perturbative gravity and supergravity by studying scattering in the ultraplanckian limit, and sharpen arguments that the dynamics is governed by long-distance physics. A simple example capturing aspects of the eikonal resummation suggests why short distance phenomena and in particular divergences or nonrenormalizability do not necessarily play a central role in this regime. A more profound problem is apparently unitarity. These considerations can be illustrated by showing that known gravity and supergravity amplitudes have the same long-distance behavior, despite the extra light states of supergravity, and this serves as an important check on long-range dynamics in a context where perturbative amplitudes are finite. We also argue that these considerations have other important implications: they obstruct probing the conjectured phenomenon of asymptotic safety through a physical scattering process, and ultraplanckian scattering exhibiting Regge behavior. These arguments sharpen the need to find a nonperturbative completion of gravity with mechanisms which restore unitarity in the strong gravity regime.

Steven B. Giddings; Maximilian Schmidt-Sommerfeld; Jeppe R. Andersen

2010-05-28T23:59:59.000Z

264

MODIFIED GRAVITY SPINS UP GALACTIC HALOS  

SciTech Connect

We investigate the effect of modified gravity on the specific angular momentum of galactic halos by analyzing the halo catalogs at z = 0 from high-resolution N-body simulations for a f(R) gravity model that meets the solar-system constraint. It is shown that the galactic halos in the f(R) gravity model tend to acquire significantly higher specific angular momentum than those in the standard {Lambda}CDM model. The largest difference in the specific angular momentum distribution between these two models occurs for the case of isolated galactic halos with mass less than 10{sup 11} h {sup -1} M {sub Sun }, which are likely least shielded by the chameleon screening mechanism. As the specific angular momentum of galactic halos is rather insensitive to other cosmological parameters, it can in principle be an independent discriminator of modified gravity. We speculate a possibility of using the relative abundance of low surface brightness galaxies (LSBGs) as a test of general relativity given that the formation of the LSBGs occurs in fast spinning dark halos.

Lee, Jounghun [Astronomy Program, Department of Physics and Astronomy, FPRD, Seoul National University, Seoul 151-747 (Korea, Republic of)] [Astronomy Program, Department of Physics and Astronomy, FPRD, Seoul National University, Seoul 151-747 (Korea, Republic of); Zhao, Gong-Bo [National Astronomy Observatories, Chinese Academy of Science, Beijing 100012 (China)] [National Astronomy Observatories, Chinese Academy of Science, Beijing 100012 (China); Li, Baojiu [Institute of Computational Cosmology, Department of Physics, Durham University, Durham DH1 3LE (United Kingdom)] [Institute of Computational Cosmology, Department of Physics, Durham University, Durham DH1 3LE (United Kingdom); Koyama, Kazuya, E-mail: jounghun@astro.snu.ac.kr [Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth, PO1 3FX (United Kingdom)] [Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth, PO1 3FX (United Kingdom)

2013-01-20T23:59:59.000Z

265

Gravity Currents in a Deep Anelastic Atmosphere  

Science Conference Proceedings (OSTI)

This study presents analytic results for steady gravity currents in a channel using the deep anelastic equations. Results are cast in terms of a nondimensional parameter H/H0 that relates the channel depth H to a scale depth H0 (the depth at ...

George H. Bryan; Richard Rotunno

2008-02-01T23:59:59.000Z

266

Gravity Waves, Dynamical Resistance, and Forcing Efficiency  

Science Conference Proceedings (OSTI)

The effect of the dynamical response associated with high-frequency gravity waves on the total energy generated by imposed heating is examined in a 2D linear compressible model. The work performed by waves against a sustained forcing is defined ...

Jeffrey M. Chagnon

2010-06-01T23:59:59.000Z

267

Flavorful hybrid anomaly-gravity mediation  

SciTech Connect

We consider supersymmetric models where anomaly and gravity mediation give comparable contributions to the soft terms and discuss how this can be realized in a five-dimensional brane world. The gaugino mass pattern of anomaly mediation is preserved in such a hybrid setup. The flavorful gravity-mediated contribution cures the tachyonic slepton problem of anomaly mediation. The supersymmetric flavor puzzle is solved by alignment. We explicitly show how a working flavor-tachyon link can be realized with Abelian flavor symmetries and give the characteristic signatures of the framework, including O(1) slepton mass splittings between different generations and between doublets and singlets. This provides opportunities for same flavor dilepton edge measurements with missing energy at the Large Hadron Collider (LHC). Rare lepton decay rates could be close to their current experimental limit. Compared to pure gravity mediation, the hybrid model is advantageous because it features a heavy gravitino which can avoid the cosmological gravitino problem of gravity-mediated models combined with leptogenesis.

Gross, Christian; Hiller, Gudrun [Institut fuer Physik, Technische Universitaet Dortmund, D-44221 Dortmund (Germany)

2011-05-01T23:59:59.000Z

268

Energy definition for quadratic curvature gravities  

E-Print Network (OSTI)

A conserved current for generic quadratic curvature gravitational models is defined, and it is shown that, at the linearized level, it corresponds to the Deser-Tekin charges. An explicit expression for the charge for new massive gravity in three dimensions is given. Some implications of the linearized equations are discussed.

Ahmet Baykal

2012-12-03T23:59:59.000Z

269

Ultrasonic hydrometer. [Specific gravity of electrolyte  

DOE Patents (OSTI)

The disclosed ultrasonic hydrometer determines the specific gravity (density) of the electrolyte of a wet battery, such as a lead-acid battery. The hydrometer utilizes a transducer that when excited emits an ultrasonic impulse that traverses through the electrolyte back and forth between spaced sonic surfaces. The transducer detects the returning impulse, and means measures the time t between the initial and returning impulses. Considering the distance d between the spaced sonic surfaces and the measured time t, the sonic velocity V is calculated with the equation V = 2d/t. The hydrometer also utilizes a thermocouple to measure the electrolyte temperature. A hydrometer database correlates three variable parameters including sonic velocity in and temperature and specific gravity of the electrolyte, for temperature values between 0 and 40/sup 0/C and for specific gravity values between 1.05 and 1.30. Upon knowing two parameters (the calculated sonic velocity and the measured temperature), the third parameter (specific gravity) can be uniquely found in the database. The hydrometer utilizes a microprocessor for data storage and manipulation.

Swoboda, C.A.

1982-03-09T23:59:59.000Z

270

Multiple Gravity-Wave Breaking Levels  

Science Conference Proceedings (OSTI)

It is noted that gravity waves for which |u¯?c| (u¯=mean flow speed, c=wave phase speed) has a sharp minimum in the upper troposphere or lower stratosphere will have decaying amplitudes above this level despite exponentially decreasing mean ...

Richard S. Lindzen

1985-02-01T23:59:59.000Z

271

Cosmological singularities and modified theories of gravity  

Science Conference Proceedings (OSTI)

We consider perturbative modifications of the Friedmann equations in terms of energy density corresponding to modified theories of gravity proposed as an alternative route to comply with the observed accelerated expansion of the universe. Assuming that the present matter content of the universe is a pressureless fluid

Leonardo Fernández?Jambrina; Ruth Lazkoz

2009-01-01T23:59:59.000Z

272

Superadiabatic Excess and Gravity Wave Saturation  

Science Conference Proceedings (OSTI)

Attention is called to a recent calculation of the superadiabatic excess—the ratio of wave amplitude at saturation to wave amplitude at convective instability threshold—caused by a saturated gravity wave. (This excess is also referred to as the ...

J. Weinstock

1988-11-01T23:59:59.000Z

273

Heat Transfer in Superfluids: Effect of Gravity  

E-Print Network (OSTI)

We discuss the influence of an external field on energy transport in superfluid. He-II is not isothermal in presence of Earth gravity; instead, it supports finite temperature gradient given by a Fourier-like equation. We calculate asymptotic behavior of the effective heat resistance in the vicinity of the $\\lambda$-transition.

L. A. Melnikovsky

2004-05-19T23:59:59.000Z

274

Charged Black Holes in New Massive Gravity  

E-Print Network (OSTI)

We construct charged black hole solutions to three-dimensional New Massive Gravity (NMG), by adding electromagnetic Maxwell and Chern-Simons actions. We find charged black holes in the form of warped AdS_3 and "log" solutions in specific critical point. The entropy, mass and angular momentum of these black holes are computed.

Ghodsi, Ahmad

2010-01-01T23:59:59.000Z

275

Free Gravity Waves and Balanced Dynamics  

Science Conference Proceedings (OSTI)

It is shown how a renormalization technique, which is a variant of classical Krylov–Bogolyubov–Mitropol'skii averaging, can be used to obtain slow evolution equations for the vortical and inertia–gravity wave components of the dynamics in a ...

D. Wirosoetisno; T. G. Shepherd; R. M. Temam

2002-12-01T23:59:59.000Z

276

Nonlinearities in modified gravity cosmology: Signatures of modified gravity in the nonlinear matter power spectrum  

SciTech Connect

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 {zeta}, which determines the enhancement of particle acceleration with respect to general relativity (GR), given the identical mass distribution ({zeta}=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 {approx}30% for 10% deviation from GR (|{zeta}-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.

Cui Weiguang; Zhang Pengjie; Yang Xiaohu [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Partner Group of MPA, Nandan Road 80, Shanghai, 200030 (China)

2010-05-15T23:59:59.000Z

277

Holographic Entanglement Entropy for 4D Conformal Gravity  

E-Print Network (OSTI)

Using the proposal for holographic entanglement entropy in higher derivative gravities, we compute holographic entanglement entropy for the conformal gravity in four dimensions which turns out to be finite. However, if one subtracts the contribution of the four dimensional Gauss-Bonnet term, the corresponding entanglement entropy has a divergent term and indeed restricted to an Einstein solution of the conformal gravity, the resultant entanglement entropy is exactly the same as that in the Einstein gravity. We will also make a comment on the first law of the entanglement thermodynamics for the conformal gravity in four dimensions.

Mohsen Alishahiha; Amin Faraji Astaneh; M. Reza Mohammadi Mozaffar

2013-11-18T23:59:59.000Z

278

On the z=4 Horava-Lifshitz Gravity  

E-Print Network (OSTI)

We consider z=4 Horava-Lifshitz gravity in both 3+1 and 4+1 dimensions. We find black hole solutions in the IR region for a kind of z=4 Horava-Lifshitz gravity which is inherited from the new massive gravity in three dimensions and an analog of the new massive gravity in four dimensions through the quantum inheritance principle. We analyze thermodynamic properties for the black hole solutions for z=4 Horava-Lifshitz gravity. We also write out the Friedmann equation in 3+1 dimensions for cosmological solutions.

Rong-Gen Cai; Yan Liu; Ya-Wen Sun

2009-04-27T23:59:59.000Z

279

Granular convection and the Brazil nut effect in reduced gravity  

E-Print Network (OSTI)

We present laboratory experiments of a vertically vibrated granular medium consisting of 1 mm diameter glass beads with embedded 8 mm diameter intruder glass beads. The experiments were performed in the laboratory as well as in a parabolic flight under reduced-gravity conditions (on Martian and Lunar gravity levels). We measured the mean rise velocity of the large glass beads and present its dependence on the fill height of the sample containers, the excitation acceleration, and the ambient gravity level. We find that the rise velocity scales in the same manner for all three gravity regimes and roughly linearly with gravity.

Carsten Güttler; Ingo von Borstel; Rainer Schräpler; Jürgen Blum

2013-04-02T23:59:59.000Z

280

Ground Gravity Survey At Coso Geothermal Area (1990) | Open Energy  

Open Energy Info (EERE)

Coso Geothermal Area (1990) Coso Geothermal Area (1990) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Coso Geothermal Area (1990) Exploration Activity Details Location Coso Geothermal Area Exploration Technique Ground Gravity Survey Activity Date 1990 Usefulness not indicated DOE-funding Unknown Exploration Basis To identify features related to the heat source and to seek possible evidence for an underlying magma chamber Notes 2D and 3D gravity modeling was done using gridded Bouguer gravity data covering a 45 by 45 km region over the Coso geothermal area. Isostatic and terrain corrected Bouguer gravity data for about 1300 gravity stations were obtained from the US Geological Survey. After the data were checked, the gravity values were gridded at 1 km centers for the area of interest

Note: This page contains sample records for the topic "gravity astm american" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Charting Transnational Native American Studies  

E-Print Network (OSTI)

Migrations and Cosmopolitan Encounters. ” AmericanMigrations and Cosmopolitan Encounters,” AmericanC. Forte, Indigenous Cosmopolitans: Transnational and

Huang, Hsinya; Deloria, Philip J.; Furlan, Laura M.; Gamber, John

2012-01-01T23:59:59.000Z

282

American Recovery and Reinvestment Act Information Services  

NLE Websites -- All DOE Office Websites (Extended Search)

Recovery and Reinvestment Act Recovery and Reinvestment Act Information Services American Recovery and Reinvestment Act American Recovery and Reinvestment Act Information Services American Recovery and Reinvestment Act American Recovery and Reinvestment Act Information Services American Recovery and Reinvestment Act American Recovery and Reinvestment Act American Recovery and Reinvestment Act American Recovery and Reinvestment Act American Recovery and Reinvestment Act American Recovery and Reinvestment Act American Recovery and Reinvestment Act American Recovery and Reinvestment Act American Recovery and Reinvestment Act American Recovery and Reinvestment Act American Recovery and Reinvestment Act American Recovery and Reinvestment Act American Recovery and Reinvestment Act American Recovery and Reinvestment Act

283

Black Holes in Three Dimensional Topological Gravity  

E-Print Network (OSTI)

We investigate the black hole solution to (2+1)-dimensional gravity coupled to topological matter, with a vanishing cosmological constant. We calculate the total energy, angular momentum and entropy of the black hole in this model and compare with results obtained in Einstein gravity. We find that the theory with topological matter reverses the identification of energy and angular momentum with the parameters in the metric, compared with general relativity, and that the entropy is determined by the circumference of the inner rather than the outer horizon. We speculate that this results from the contribution of the topological matter fields to the conserved currents. We also briefly discuss two new possible (2+1)-dimensional black holes.

S. Carlip; J. Gegenberg; R. B. Mann

1994-10-17T23:59:59.000Z

284

A perspective on Quantum Gravity Phenomenology  

E-Print Network (OSTI)

I give a brief overview of some Quantum-Gravity-Phenomenology research lines, focusing on studies of cosmic rays and gamma-ray bursts that concern the fate of Lorentz symmetry in quantum spacetime. I also stress that the most valuable phenomenological analyses should not mix too many conjectured new features of quantum spacetime, and from this perspective it appears that it should be difficult to obtain reliable guidance on the quantum-gravity problem from the analysis of synchrotron radiation from the Crab nebula and from the analysis of phase coherence of light from extragalactic sources. Forthcoming observatories of ultra-high-energy neutrinos should provide several opportunities for clean tests of some simple hypothesis for the short-distance structure of spacetime. In particular, these neutrino studies, and some related cosmic-ray studies, should provide access to the regime $E>\\sqrt{m E_p}$.

Giovanni Amelino-Camelia

2004-02-02T23:59:59.000Z

285

Non-Newtonian gravity in finite nuclei  

E-Print Network (OSTI)

In this talk, we report our recent study of constraining the non-Newtonian gravity at femtometer scale. We incorporate the Yukawa-type non-Newtonian gravitational potential consistently to the Skyrme functional form using the exact treatment for the direct contribution and density-matrix expansion method for the exchange contribution. The effects from the non-Newtonian potential on finite nuclei properties are then studied together with a well-tested Skyrme force. Assuming that the framework without non-Newtonian gravity can explain the binding energies and charge radii of medium to heavy nuclei within 2% error, we set an upper limit for the strength of the non-Newtonian gravitational potential at femtometer scale.

Xu, Jun; Chen, Lie-Wen; Zheng, Hao

2012-01-01T23:59:59.000Z

286

Hydrogen atom in Palatini theories of gravity  

E-Print Network (OSTI)

We study the effects that the gravitational interaction of $f(R)$ theories of gravity in Palatini formalism has on the stationary states of the Hydrogen atom. We show that the role of gravity in this system is very important for lagrangians $f(R)$ with terms that grow at low curvatures, which have been proposed to explain the accelerated expansion rate of the universe. We find that new gravitationally induced terms in the atomic Hamiltonian generate a strong backreaction that is incompatible with the very existence of bound states. In fact, in the 1/R model, Hydrogen disintegrates in less than two hours. The universe that we observe is, therefore, incompatible with that kind of gravitational interaction. Lagrangians with high curvature corrections do not lead to such instabilities.

Gonzalo J. Olmo

2008-02-27T23:59:59.000Z

287

Modified Gravity via Spontaneous Symmetry Breaking  

E-Print Network (OSTI)

We construct effective field theories in which gravity is modified via spontaneous breaking of local Lorentz invariance. This is a gravitational analogue of the Higgs mechanism. These theories possess additional graviton modes and modified dispersion relations. They are manifestly well-behaved in the UV and free of discontinuities of the van Dam-Veltman-Zakharov type, ensuring compatibility with standard tests of gravity. They may have important phenomenological effects on large distance scales, offering an alternative to dark energy. For the case in which the symmetry is broken by a vector field with the wrong sign mass term, we identify four massless graviton modes (all with positive-definite norm for a suitable choice of a parameter) and show the absence of the discontinuity.

B. M. Gripaios

2004-08-17T23:59:59.000Z

288

Holographic Superconductivity with Gauss-Bonnet gravity  

E-Print Network (OSTI)

I review recent work on holographic superconductivity with Einstein-Gauss-Bonnet gravity, and show how the critical temperature of the superconductor depends on both gravitational backreaction and the Gauss-Bonnet parameter, using both analytic and numerical arguments. I also review computations of the conductivity, finding the energy gap, and demonstrating that there is no universal gap ratio, $\\omega_g/T_c$, for these superconductors.

Ruth Gregory

2010-12-07T23:59:59.000Z

289

Gravity controlled anti-reverse rotation device  

DOE Patents (OSTI)

A gravity assisted anti-reverse rotation device for preventing reverse rotation of pumps and the like. A horizontally mounted pawl is disposed to mesh with a fixed ratchet preventing reverse rotation when the pawl is advanced into intercourse with the ratchet by a vertically mounted lever having a lumped mass. Gravitation action on the lumped mass urges the pawl into mesh with the ratchet, while centrifugal force on the lumped mass during forward, allowed rotation retracts the pawl away from the ratchet.

Dickinson, Robert J. (Shaler Township, Allegheny County, PA); Wetherill, Todd M. (Lower Burrell, PA)

1983-01-01T23:59:59.000Z

290

1 Quantum Gravity and Regge Calculus  

E-Print Network (OSTI)

This is an informal review of the formulation of canonical general relativity and of its implications for quantum gravity; the various versions are compared, both in the continuum and in a discretized approximation suggested by Regge calculus. I also show that the weakness of the link with the geometric content of the theory gives rise to what I think is a serious flaw in the claimed derivation of a discrete structure for space at the quantum level. 1.

Giorgio Immirzi A

1997-01-01T23:59:59.000Z

291

Twisted covariant noncommutative self-dual gravity  

Science Conference Proceedings (OSTI)

A twisted covariant formulation of noncommutative self-dual gravity is presented. The formulation for constructing twisted noncommutative Yang-Mills theories is used. It is shown that the noncommutative torsion is solved at any order of the {theta} expansion in terms of the tetrad and some extra fields of the theory. In the process the first order expansion in {theta} for the Plebanski action is explicitly obtained.

Estrada-Jimenez, S.; Garcia-Compean, H.; Obregon, O.; Ramirez, C. [Centro de Estudios en Fisica y Matematicas Basicas y Aplicadas, Universidad Autonoma de Chiapas, Calle 4 Oriente Norte 1428, Tuxtla Gutierrez, Chiapas (Mexico); Departamento de Fisica, Centro de Investigacion y de Estudios Avanzados del IPN, P.O. Box 14-740, 07000 Mexico D.F. (Mexico); Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Monterrey, PIIT, Via del Conocimiento 201, Autopista nueva al Aeropuerto km 9.5, 66600, Apodaca Nuevo Leon (Mexico); Instituto de Fisica de la Universidad de Guanajuato, P.O. Box E-143, 37150, Leon Gto. (Mexico); Facultad de Ciencias Fisico Matematicas, Universidad Autonoma de Puebla, P.O. Box 1364, 72000, Puebla (Mexico)

2008-12-15T23:59:59.000Z

292

Flipped spinfoam vertex and loop gravity  

E-Print Network (OSTI)

We introduce a vertex amplitude for 4d loop quantum gravity. We derive it from a conventional quantization of a Regge discretization of euclidean general relativity. This yields a spinfoam sum that corrects some difficulties of the Barrett-Crane theory. The second class simplicity constraints are imposed weakly, and not strongly as in Barrett-Crane theory. Thanks to a flip in the quantum algebra, the boundary states turn out to match those of SO(3) loop quantum gravity -- the two can be identified as eigenstates of the same physical quantities -- providing a solution to the problem of connecting the covariant SO(4) spinfoam formalism with the canonical SO(3) spin-network one. The vertex amplitude is SO(3) and SO(4)-covariant. It rectifies the triviality of the intertwiner dependence of the Barrett-Crane vertex, which is responsible for its failure to yield the correct propagator tensorial structure. The construction provides also an independent derivation of the kinematics of loop quantum gravity and of the result that geometry is quantized.

Jonathan Engle; Roberto Pereira; Carlo Rovelli

2007-08-09T23:59:59.000Z

293

Geometry and symmetries in lattice spinor gravity  

SciTech Connect

Lattice spinor gravity is a proposal for regularized quantum gravity based on fermionic degrees of freedom. In our lattice model the local Lorentz symmetry is generalized to complex transformation parameters. The difference between space and time is not put in a priori, and the euclidean and the Minkowski quantum field theory are unified in one functional integral. The metric and its signature arise as a result of the dynamics, corresponding to a given ground state or cosmological solution. Geometrical objects as the vierbein, spin connection or the metric are expectation values of collective fields built from an even number of fermions. The quantum effective action for the metric is invariant under general coordinate transformations in the continuum limit. The action of our model is found to be also invariant under gauge transformations. We observe a 'geometrical entanglement' of gauge- and Lorentz-transformations due to geometrical objects transforming non-trivially under both types of symmetry transformations. - Highlights: Black-Right-Pointing-Pointer We formulate the geometrical aspects of a proposal for a lattice regularized model of quantum gravity. Black-Right-Pointing-Pointer The vierbein shows an entanglement between Lorentz symmetry and gauge symmetry. Black-Right-Pointing-Pointer Euclidean and Minkowski signatures of the collective metric and the vierbein are described within the same functional integral.

Wetterich, C., E-mail: c.wetterich@thphys.uni-heidelberg.de

2012-09-15T23:59:59.000Z

294

Distinguishing Modified Gravity from Dark Energy  

E-Print Network (OSTI)

The acceleration of the universe can be explained either through dark energy or through the modification of gravity on large scales. In this paper we investigate modified gravity models and compare their observable predictions with dark energy models. Modifications of general relativity are expected to be scale-independent on super-horizon scales and scale-dependent on sub-horizon scales. For scale-independent modifications, utilizing the conservation of the curvature scalar and a parameterized post-Newtonian formulation of cosmological perturbations, we derive results for large scale structure growth, weak gravitational lensing, and cosmic microwave background anisotropy. For scale-dependent modifications, inspired by recent $f(R)$ theories we introduce a parameterization for the gravitational coupling $G$ and the post-Newtonian parameter $\\gamma$. These parameterizations provide a convenient formalism for testing general relativity. However, we find that if dark energy is generalized to include both entropy and shear stress perturbations, and the dynamics of dark energy is unknown a priori, then modified gravity cannot in general be distinguished from dark energy using cosmological linear perturbations.

Edmund Bertschinger; Phillip Zukin

2008-01-16T23:59:59.000Z

295

Supermassive galactic centre with repulsive gravity  

E-Print Network (OSTI)

Repulsive gravity has its origin in the 1939 article of Oppenheimer and Snyder which describes a collapsar, that is an idealized star of non-interacting material (dust) collapsing under its own gravity. The stellar material has a final state resembling a football, that is a significant part of it is concentrated in a thin surface shell. An interior pressure is exerted by the strong gravitational field, equivalent to a negative mass. However, the OS solution has been misunderstood, the shell's position being incorrectly identified with the "event horizon" in black-hole theory. While half the material is concentrated in a shell occupying a small fraction of the radius, some material is spread throughout the interior, unlike the concentration in a black hole's singularity. We deal with the singularity in density at the shell surface, by including Fermi pressure of degenerate electrons for a shell density comparable to a solar mass-sized white dwarf. Because the high-density region is concentrated in a shell, instead of at the centre as in a black hole, our conclusion is that repulsive gravity enables the existence of supermassive white dwarfs.

Trevor W. Marshall; Max K. Wallis

2013-03-18T23:59:59.000Z

296

Primordial nucleosynthesis in conformal Weyl gravity  

DOE Green Energy (OSTI)

Recently conformal Weyl gravity has been considered as a candidate alternative gravity theory. This fourth-order theory is attractive because it is the only metric theory of gravity which is invariant under local conformal transformations of the metric. The authors calculate the primordial light element abundances in this theory. The major difference from the standard cosmology is that the universe expands far more slowly throughout the nucleosynthesis epoch. The production of {sup 4}He depends strongly on {eta}, the ratio of baryons to photons. For {eta} = 10{sup {minus}8} the mass fraction of {sup 4}He is X{sub 4} {approx_equal} 0.25 and the number densities relative to hydrogen for {sup 2}H, {sup 3}He and {sup 7}Li are n({sup 2}H)/n(H) {approx_equal} 9 {times} 10{sup {minus}20}, n({sup 3}He)/n(H) {approx_equal}4 {times} 10{sup {minus}18} and n({sup 7}Li)/n(H) {approx_equal} 10{sup {minus}13}. This value of {eta} corresponds to a baryon mass density close to the standard model critical density. However, adjusting {eta} to give a reasonable helium yield forces the deuterium and lithium yields to be small enough that the theory cannot be reconciled with observations.

Knox, L.; Kosowsky, A. [Univ. of Chicago, IL (United States). Enrico Fermi Inst.]|[Fermi National Accelerator Lab., Batavia, IL (United States)

1993-10-01T23:59:59.000Z

297

Lorentz covariance of loop quantum gravity  

SciTech Connect

The kinematics of loop gravity can be given a manifestly Lorentz-covariant formulation: the conventional SU(2)-spin-network Hilbert space can be mapped to a space K of SL(2,C) functions, where Lorentz covariance is manifest. K can be described in terms of a certain subset of the projected spin networks studied by Livine, Alexandrov and Dupuis. It is formed by SL(2,C) functions completely determined by their restriction on SU(2). These are square-integrable in the SU(2) scalar product, but not in the SL(2,C) one. Thus, SU(2)-spin-network states can be represented by Lorentz-covariant SL(2,C) functions, as two-component photons can be described in the Lorentz-covariant Gupta-Bleuler formalism. As shown by Wolfgang Wieland in a related paper, this manifestly Lorentz-covariant formulation can also be directly obtained from canonical quantization. We show that the spinfoam dynamics of loop quantum gravity is locally SL(2,C)-invariant in the bulk, and yields states that are precisely in K on the boundary. This clarifies how the SL(2,C) spinfoam formalism yields an SU(2) theory on the boundary. These structures define a tidy Lorentz-covariant formalism for loop gravity.

Rovelli, Carlo; Speziale, Simone [Centre de Physique Theorique de Luminy, Case 907, F-13288 Marseille (France)

2011-05-15T23:59:59.000Z

298

The Gravity Dual of the Ising Model  

E-Print Network (OSTI)

We evaluate the partition function of three dimensional theories of gravity in the quantum regime, where the AdS radius is Planck scale and the central charge is of order one. The contribution from the AdS vacuum sector can - with certain assumptions - be computed and equals the vacuum character of a minimal model CFT. The torus partition function is given by a sum over geometries which is finite and computable. For generic values of Newton's constant G and the AdS radius L the result has no Hilbert space interpretation, but in certain cases it agrees with the partition function of a known CFT. For example, the partition function of pure Einstein gravity with G=3L equals that of the Ising model, providing evidence that these theories are dual. We also present somewhat weaker evidence that the 3-state and tricritical Potts models are dual to pure higher spin theories of gravity based on SL(3) and E_6, respectively.

Alejandra Castro; Matthias R. Gaberdiel; Thomas Hartman; Alexander Maloney; Roberto Volpato

2011-11-08T23:59:59.000Z

299

The Gravity Dual of the Ising Model  

E-Print Network (OSTI)

We evaluate the partition function of three dimensional theories of gravity in the quantum regime, where the AdS radius is Planck scale and the central charge is of order one. The contribution from the AdS vacuum sector can - with certain assumptions - be computed and equals the vacuum character of a minimal model CFT. The torus partition function is given by a sum over geometries which is finite and computable. For generic values of Newton's constant G and the AdS radius L the result has no Hilbert space interpretation, but in certain cases it agrees with the partition function of a known CFT. For example, the partition function of pure Einstein gravity with G=3L equals that of the Ising model, providing evidence that these theories are dual. We also present somewhat weaker evidence that the 3-state and tricritical Potts models are dual to pure higher spin theories of gravity based on SL(3) and E_6, respectively.

Castro, Alejandra; Hartman, Thomas; Maloney, Alexander; Volpato, Roberto

2011-01-01T23:59:59.000Z

300

Native American Heritage Month  

Energy.gov (U.S. Department of Energy (DOE))

This month, we celebrate the rich heritage and myriad contributions of American Indians and Alaska Natives, and we rededicate ourselves to supporting tribal sovereignty, tribal self-determination,...

Note: This page contains sample records for the topic "gravity astm american" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
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301

American Chemical Society  

Science Conference Proceedings (OSTI)

*. Bookmark and Share. American Chemical Society (ACS). Purpose: Air and water mediate chemistry on Earth. ... Related Project(s): ACS. Details: ...

2011-08-29T23:59:59.000Z

302

Aging in American Convents  

E-Print Network (OSTI)

Schuster. Snowdon, David 2001 Aging with Grace: What the Nunreligion, devotion, and aging. CSW JAN09 update tocAging in American Convents FIELDWORK REPORT by Anna I.

Corwin, Anna I.

2009-01-01T23:59:59.000Z

303

New Agegraphic Dark Energy in $f(R)$ Gravity  

E-Print Network (OSTI)

In this paper we study cosmological application of new agegraphic dark energy density in the $f(R)$ gravity framework. We employ the new agegraphic model of dark energy to obtain the equation of state for the new agegraphic energy density in spatially flat universe. Our calculation show, taking $nenergy model in flat universe in the modified gravity cosmology framework. Also we develop a reconstruction scheme for the modified gravity with $f(R)$ action.

Setare, M R

2009-01-01T23:59:59.000Z

304

New Agegraphic Dark Energy in $f(R)$ Gravity  

E-Print Network (OSTI)

In this paper we study cosmological application of new agegraphic dark energy density in the $f(R)$ gravity framework. We employ the new agegraphic model of dark energy to obtain the equation of state for the new agegraphic energy density in spatially flat universe. Our calculation show, taking $nenergy model in flat universe in the modified gravity cosmology framework. Also we develop a reconstruction scheme for the modified gravity with $f(R)$ action.

M. R. Setare

2009-08-03T23:59:59.000Z

305

AdS waves as exact solutions to quadratic gravity  

SciTech Connect

We give an exact solution of the quadratic gravity in D dimensions. The solution is a plane-fronted wave metric with a cosmological constant. This metric solves not only the full quadratic gravity field equations but also the linearized ones which include the linearized equations of the recently found critical gravity. A subset of the solutions change the asymptotic structure of the anti-de Sitter space due to their logarithmic behavior.

Guellue, Ibrahim; Sisman, Tahsin Cagri; Tekin, Bayram [Department of Physics, Middle East Technical University, 06531 Ankara (Turkey); Guerses, Metin [Department of Mathematics, Faculty of Sciences Bilkent University, 06800 Ankara (Turkey)

2011-04-15T23:59:59.000Z

306

Gravity Couplings in the Standard-Model Extension  

E-Print Network (OSTI)

The Standard-Model Extension (SME) is an action-based expansion describing general Lorentz violation for known matter and fields, including gravity. In this talk, I will discuss the Lorentz-violating gravity couplings in the SME. Toy models that match the SME expansion, including vector and two-tensor models, are reviewed. Finally I discuss the status of experiments and observations probing gravity coefficients for Lorentz violation.

Bailey, Quentin G

2010-01-01T23:59:59.000Z

307

Solar System experiments do not yet veto modified gravity models  

E-Print Network (OSTI)

The dynamical equivalence between modified and scalar-tensor gravity theories is revisited and it is concluded that it breaks down in the limit to general relativity. A gauge-independent analysis of cosmological perturbations in both classes of theories lends independent support to this conclusion. As a consequence, the PPN formalism of scalar-tensor gravity and Solar System experiments do not veto modified gravity, as previously thought.

Valerio Faraoni

2006-07-05T23:59:59.000Z

308

pmm.vp  

U.S. Energy Information Administration (EIA) Indexed Site

API API Gravity: An arbitrary scale expressing the gravity or density of liquid petroleum products. The measuring scale is calibrated in terms of degrees API; it may be calculated in terms of the following formula: Degrees API sp gr F o = - 1415 60 1315 . . . @ . The higher the API gravity, the lighter the compound. Light crudes generally exceed 38 degrees API and heavy crudes are commonly labeled as all crudes with an API gravity of 22 degrees or below. Intermediate crudes fall in the range of 22 degrees to 38 degrees API gravity. ASTM: American Society for Testing and Materials. Aviation Gasoline (Finished): A complex mixture of relatively volatile hydrocarbons with or without small quantities of additives, blended to form a fuel suitable for use in aviation reciprocating engines. Fuel specifications are provided in ASTM Specification D 910 and Military Specification MIL-G-5572. Note: Data

309

Exercise protocols during short-radius centrifugation for artificial gravity  

E-Print Network (OSTI)

Long-duration spaceflight results in severe physiological deconditioning, threatening the success of interplanetary travel. Exercise combined with artificial gravity provided by centrifugation may be the comprehensive ...

Edmonds, Jessica Leigh

2008-01-01T23:59:59.000Z

310

Ground Gravity Survey At Newberry Caldera Area (DOE GTP) | Open...  

Open Energy Info (EERE)

GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Newberry Caldera Area (DOE GTP) Exploration Activity Details Location Newberry Caldera Area...

311

Ground Gravity Survey At Under Steamboat Springs Area (Warpinski...  

Open Energy Info (EERE)

to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Under Steamboat Springs Area (Warpinski, Et Al., 2002) Exploration Activity...

312

Ground Gravity Survey At San Francisco Volcanic Field Area (Warpinski...  

Open Energy Info (EERE)

Ground Gravity Survey At San Francisco Volcanic Field Area (Warpinski, Et Al., 2004) Exploration Activity Details Location San Francisco Volcanic Field Area Exploration Technique...

313

Ground Gravity Survey At Cove Fort Area - Vapor (Warpinski, Et...  

Open Energy Info (EERE)

to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Cove Fort Area (Warpinski, Et Al., 2004) Exploration Activity Details...

314

Ground Gravity Survey At Lake City Hot Springs Area (Warpinski...  

Open Energy Info (EERE)

to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Lake City Hot Springs Area (Warpinski, Et Al., 2004) Exploration Activity...

315

Ground Gravity Survey At Coso Geothermal Area (1980) | Open Energy...  

Open Energy Info (EERE)

Activity Details Location Coso Geothermal Area Exploration Technique Ground Gravity Survey Activity Date 1980 Usefulness not indicated DOE-funding Unknown Notes The...

316

Reconstruction of modified gravity with ghost dark energy models  

E-Print Network (OSTI)

In this work, we reconstruct the $f(R)$ modified gravity for different ghost and generalized ghost dark energy models in FRW flat universe, which describe the accelerated expansion of the universe. The equation of state of reconstructed $f(R)$ - gravity has been calculated. We show that the corresponding $f(R)$ gravity of ghost dark energy model can behave like phantom or quintessence. We also show that the equation of state of reconstructed $f(R)$ gravity for generalized ghost model can transit from quintessence regime to the phantom regime as indicated by recent observations.

Khodam-Mohammadi, A

2012-01-01T23:59:59.000Z

317

Effect of Centrifugal And Gravity Casting Technique over ...  

Science Conference Proceedings (OSTI)

In this work an attempt is made to study the effect of centrifugal and gravity casting ... A Minimum Pollution, Low Energy Process for the Recovery of Cobalt and ...

318

Ground Gravity Survey At Kilauea East Rift Area (Broyles, Et...  

Open Energy Info (EERE)

Activity Details Location Kilauea East Rift Area Exploration Technique Ground Gravity Survey Activity Date Usefulness not indicated DOE-funding Unknown References M. L....

319

Lorentz Invariant phenomenological model of quantum gravity: A minimalistic presentation  

SciTech Connect

The purpose of this paper is to give a minimalistic and self-contained presentation of a Lorentz Invariant phenomenological model of Quantum Gravity.

Bonder, Yuri [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico Apartado Postal 70-543, Distrito Federal 04510 (Mexico)

2012-08-24T23:59:59.000Z

320

Ground Gravity Survey At Dixie Valley Geothermal Field Area ...  

Open Energy Info (EERE)

In Dixie Valley, Nevada Retrieved from "http:en.openei.orgwindex.php?titleGroundGravitySurveyAtDixieValleyGeothermalFieldArea(Blackwell,EtAl.,2009)&oldid38834...

Note: This page contains sample records for the topic "gravity astm american" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Ground Gravity Survey At Under Steamboat Springs Area (Warpinski...  

Open Energy Info (EERE)

to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Under Steamboat Springs Area (Warpinski, Et Al., 2004) Exploration Activity...

322

Ground Gravity Survey At Walker Lake Valley Area (Shoffner, Et...  

Open Energy Info (EERE)

to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Walker Lake Valley Area (Shoffner, Et Al., 2010) Exploration Activity...

323

Ground Gravity Survey At Baltazor Hot Springs Area (Isherwood...  

Open Energy Info (EERE)

to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Baltazor Hot Springs Area (Isherwood & Mabey, 1978) Exploration Activity...

324

Ground Gravity Survey At Raft River Geothermal Area (1978) |...  

Open Energy Info (EERE)

Activity Details Location Raft River Geothermal Area Exploration Technique Ground Gravity Survey Activity Date 1978 Usefulness not indicated DOE-funding Unknown Exploration...

325

Hidden Lorentz symmetry of the Horava - Lifshitz gravity  

E-Print Network (OSTI)

In this letter it is shown that the Horava-Lifshitz gravity theory admits Lorentz symmetry preserving preferred global time foliation of the spacetime.

Jakub Rembielinski

2013-09-03T23:59:59.000Z

326

Gravity wave coupling of the lower and middle atmosphere.  

E-Print Network (OSTI)

??A method of inferring tropospheric gravity wave source characteristics from middle atmosphere observations has been adapted from previous studies for use with MF radar observations… (more)

Love, Peter Thomas

2009-01-01T23:59:59.000Z

327

Jefferson Lab Science Series - Detecting Einstein's Gravity Waves  

NLE Websites -- All DOE Office Websites (Extended Search)

Science Series Video Archive Next Video (Symmetry) Symmetry Detecting Einstein's Gravity Waves Dr. David Shoemaker - Massachusetts Institute of Technology March 18, 1997 LIGO...

328

Effects of Gravity on the Columnar to Equiaxed Transition in ...  

Science Conference Proceedings (OSTI)

The effects of gravity, thermal natural convection and dendrite transport were integrated into the model. Simulations of vertical directional solidification of an ...

329

Gravity in Randall-Sundrum two D-brane model  

E-Print Network (OSTI)

We analyse Randall-Sundrum two D-brane model by linear perturbation and then consider the linearised gravity on the D-brane. The qualitative contribution from the Kaluza-Klein modes of gauge fields to the coupling to the gravity on the brane will be addressed. As a consequence, the gauge fields localised on the brane are shown not to contribute to the gravity on the brane at large distances. Although the coupling between gauge fields and gravity appears in the next order, the ordinary coupling cannot be realised.

Tetsuya Shiromizu; Keitaro Takahashi; Yoshiaki Himemoto; Shuto Yamamoto

2004-07-30T23:59:59.000Z

330

The Link Between Gravity Recovery and Hydrometallurgy - TMS  

Science Conference Proceedings (OSTI)

Aug 1, 2003 ... The Link Between Gravity Recovery and Hydrometallurgy: The Case of Gold by A.R. Laplante and W. Staunton ...

331

Can gravity be added to Pilot Wave models?  

E-Print Network (OSTI)

The purpose of this paper is to come up with one of the many possible schemes of "adding" gravity to Pilot Wave models.

Sverdlov, Roman

2010-01-01T23:59:59.000Z

332

Polytropic and Chaplygin f(R)-gravity models  

E-Print Network (OSTI)

We reconstruct different f(R)-gravity models corresponding to the polytropic, standard Chaplygin, generalized Chaplygin, modified Chaplygin and modified variable Chaplygin gas dark energy models. We also obtain the equation of state parameters of the corresponding f(R)-gravity models which describe the accelerated expansion of the universe. We conclude that although the equation of state parameters of the obtained f(R)-gravities can behave like phantom or quintessence dark energy models, they cannot justify the transition from the quintessence state to the phantom regime. Furthermore, the polytropic and Chaplygin f(R)-gravity models in de Sitter space can satisfy the inflation condition.

K. Karami; M. S. Khaledian

2010-10-13T23:59:59.000Z

333

Regional Gravity Survey of the Northern Great Salt Lake Desert...  

Open Energy Info (EERE)

of the Northern Great Salt Lake Desert and Adjacent Areas in Utah, Nevada, and Idaho Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Regional Gravity...

334

Evolution of Gold Gravity Recovery in Grinding Circuits - A Critical ...  

Science Conference Proceedings (OSTI)

Presentation Title, Evolution of Gold Gravity Recovery in Grinding Circuits - A Critical .... Selective Separations of Gold and Contaminants from Various Gold and ...

335

Ground Gravity Survey At Snake River Plain Region (DOE GTP) ...  

Open Energy Info (EERE)

Snake River Plain Region (DOE GTP) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Snake River Plain Region (DOE GTP)...

336

Testing general scalar-tensor gravity and massive gravity with cluster lensing  

E-Print Network (OSTI)

We explore the possibility of testing modified gravity exhibiting the Vainshtein mechanism against observations of cluster lensing. We work in the most general scalar-tensor theory with second-order field equations (Horndeski's theory), and derive static and spherically symmetric solutions, for which the scalar field is screened below a certain radius. It is found that the essential structure of the problem in the most general case can be captured by the program of classifying Vainshtein solutions out of different solutions to a quintic equation, as has been performed in the context of massive gravity. The key effect on gravitational lensing is that the second derivative of the scalar field can substantially be large at the transition from screened to unscreened regions, leaving a dip in the convergence. This allows us to put observational constraints on parameters characterizing the general scalar-tensor modification of gravity. We demonstrate how this occurs in massive gravity as an example, and discuss its observational signatures in cluster lensing.

Tatsuya Narikawa; Tsutomu Kobayashi; Daisuke Yamauchi; Ryo Saito

2013-02-10T23:59:59.000Z

337

Conservation laws for vacuum tetrad gravity  

E-Print Network (OSTI)

Ten conservation laws in useful polynomial form are derived from a Cartan form and Exterior Differential System (EDS) for the tetrad equations of vacuum relativity. The Noether construction of conservation laws for well posed EDS is introduced first, and an illustration given, deriving 15 conservation laws of the free field Maxwell Equations from symmetries of its EDS. The Maxwell EDS and tetrad gravity EDS have parallel structures, with their numbers of dependent variables, numbers of generating 2-forms and generating 3-forms, and Cartan character tables all in the ratio of 1 to 4. They have 10 corresponding symmetries with the same Lorentz algebra, and 10 corresponding conservation laws.

Frank B. Estabrook

2005-08-20T23:59:59.000Z

338

Conservation of energy and Gauss Bonnet gravity  

E-Print Network (OSTI)

It is shown how can be made the classification of all tensors constructed from the Riemann tensor that verify the conservation of gravitational energy momentum. More precisely we explain that there exists a unique tensor of degree n in the Riemann tensor and its contractions that verifies the conservation of energy. We show that this tensor, only because it obeys this degree n structure as well as energy conservation, two facts which are true in all dimensions, verifies in dimension 2n this striking particularity of being Euler gravity. We stick here to the case n=2 but explain briefly why the general case is similar.

Christophe Real

2006-12-21T23:59:59.000Z

339

Geophysics IV. Gravity, Magnetic, and Magnetotelluric Methods  

SciTech Connect

During the past two decades, the technology of geophysics has exploded. At the same time, the petroleum industry has been forced to look for more and more subtle traps in more and more difficult terrain. The choice of papers in this geophysics reprint volume reflects this evolution. The papers were chosen to help geologists, not geophysicists, enhance their knowledge of geophysics. Math-intensive papers were excluded because those papers are relatively esoteric and have limited applicability for most geologists. This volume concentrates on gravity, magnetic, and magnetotelluric methods. Each of the 10 papers were abstracted and indexed for the U.S. Department of Energy's Energy Data Base.

Beaumont, E.A.; Foster, N.H. (comps.)

1989-01-01T23:59:59.000Z

340

Bringing Together Gravity and the Quanta  

E-Print Network (OSTI)

Due to its underlying gauge structure, teleparallel gravity achieves a separation between inertial and gravitational effects. It can, in consequence, describe the isolated gravitational interaction without resorting to the equivalence principle, and is able to provide a tensorial definition for the energy-momentum density of the gravitational field. Considering the conceptual conflict between the local equivalence principle and the nonlocal uncertainty principle, the replacement of general relativity by its teleparallel equivalent can be considered an important step towards a prospective reconciliation between gravitation and quantum mechanics.

R. Aldrovandi; L. C. T. Guillen; J. G. Pereira; K. H. Vu

2006-03-30T23:59:59.000Z

Note: This page contains sample records for the topic "gravity astm american" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

The dualities of 3D dilaton gravity  

E-Print Network (OSTI)

We investigate Brans-Dicke dilaton gravity theories in 2+1 dimensions. We show that the reduced field equations for solutions with diagonal metric and depending only on one spacetime coordinate have a continuous O(2) symmetry. Using this symmetry we derive general static and cosmological solutions of the theory. The action of the discrete group O(2,Z) on the space of the solutions is discussed. Three-dimensional string effective theory and three-dimensional general relativity are discussed in detail. In particular, we find that the previously discovered black string solution is dual to a spacetime with a conical singularity.

Mariano Cadoni

1996-06-17T23:59:59.000Z

342

Gravity duals for non-relativistic CFTs  

E-Print Network (OSTI)

We attempt to generalize the AdS/CFT correspondence to non-relativistic conformal field theories which are invariant under Galilean transformations. Such systems govern ultracold atoms at unitarity, nucleon scattering in some channels, and more generally, a family of universality classes of quantum critical behavior. We construct a family of metrics which realize these symmetries as isometries. They are solutions of gravity with negative cosmological constant coupled to pressureless dust. We discuss realizations of the dust, which include a bulk superconductor. We develop the holographic dictionary and compute some two-point correlators. A strange aspect of the correspondence is that the bulk geometry has two extra noncompact dimensions.

Koushik Balasubramanian; John McGreevy

2008-04-25T23:59:59.000Z

343

Thermodynamics of 5D dilaton-gravity  

Science Conference Proceedings (OSTI)

We calculate the free energy, spatial string tension and Polyakov loop of the gluon plasma using the dilaton potential of Ref. [1] in the dilaton-gravity theory of AdS/QCD. The free energy is computed from the Black Hole solutions of the Einstein equations in two ways: first, from the Bekenstein-Hawking proportionality of the entropy with the area of the horizon, and secondly from the Page-Hawking computation of the free energy. The finite temperature behaviour of the spatial string tension and Polyakov loop follow from the corresponding string theory in AdS{sub 5}. Comparison with lattice data is made.

Megias, E. [Institute for Theoretical Physics, University of Heidelberg (Germany); Instituto de Fisica Teorica CSIC-UAM, Universidad Autonoma de Madrid (Spain)

2011-05-23T23:59:59.000Z

344

Maxwell's equations, linear gravity, and twistors  

SciTech Connect

A detailed outline is presented of several convergent points of view connecting the self-dual and anti-self-dual fields with their free data. This is doen for the Maxwell and for linearized gravity as exemplifying the approaches. The Sparling equation provides one tool of great power and characterizes one approach. The twistor theory of Penrose yields another equally powerful point of view. The links between these two basic approaches given in this paper provide a unification that allows workers and others with interest in this area to proceed more readily toward the goal of understanding the full nonlinear Einstein equations.

Kozameh, C.N.; Newman, E.T.; Porter, J.R.

1984-11-01T23:59:59.000Z

345

Seven-Dimensional Gravity with Topological Terms  

E-Print Network (OSTI)

We construct new seven-dimensional gravity by adding two topological terms to the Einstein-Hilbert action. For certain choice of the coupling constants, these terms may be related to the R^4 correction to the 3-form field equation of eleven-dimensional supergravity. We derive the full set of the equations of motion. We find that the static spherically-symmetric black holes are unmodified by the topological terms. We obtain squashed AdS_7, and also squashed seven spheres and Q^{111} spaces in Euclidean signature.

H. Lu; Yi Pang

2009-12-30T23:59:59.000Z

346

Lorentz Invariance Violation in Modified Gravity  

E-Print Network (OSTI)

We consider an environmentally dependent violation of Lorentz invariance in scalar-tensor models of modified gravity where General Relativity is retrieved locally thanks to a screening mechanism. We find that fermions have a modified dispersion relation and would go faster than light in an anisotropic and space-dependent way along the scalar field lines of force. We analyse briefly the OPERA results and show that they could be reproduced with chameleon models. We suggest that neutrinos emitted radially, at different energies, and observed on the other side of the earth would provide a test of these models.

Brax, Philippe

2012-01-01T23:59:59.000Z

347

Gamma Ray Burst Neutrinos Probing Quantum Gravity  

E-Print Network (OSTI)

Very high energy, short wavelength, neutrinos may interact with the space-time foam predicted by theories of quantum gravity. They would propagate like light through a crystal lattice and be delayed, with the delay depending on the energy. This will appear to the observer as a violation of Lorenz invariance. Back of the envelope calculations imply that observations of neutrinos produced by gamma ray bursts may reach Planck-scale sensitivity. We revisit the problem considering two essential complications: the imprecise timing of the neutrinos associated with their poorly understood production mechanism in the source and the indirect nature of their energy measurement made by high energy neutrino telescopes.

M. C. Gonzalez-Garcia; F. Halzen

2006-11-28T23:59:59.000Z

348

Hall viscosity from gauge/gravity duality  

E-Print Network (OSTI)

In (2+1)-dimensional systems with broken parity, there exists yet another transport coefficient, appearing at the same order as the shear viscosity in the hydrodynamic derivative expansion. In condensed matter physics, it is referred to as "Hall viscosity". We consider a simple holographic realization of a (2+1)-dimensional isotropic fluid with broken spatial parity. Using techniques of fluid/gravity correspondence, we uncover that the holographic fluid possesses a nonzero Hall viscosity, whose value only depends on the near-horizon region of the background. We also write down a Kubo's formula for the Hall viscosity. We confirm our results by directly computing the Hall viscosity using the formula.

Omid Saremi; Dam Thanh Son

2011-03-24T23:59:59.000Z

349

Robust approach to f(R) gravity  

Science Conference Proceedings (OSTI)

We consider metric f(R) theories of gravity without mapping them to their scalar-tensor counterpart, but using the Ricci scalar itself as an ''extra'' degree of freedom. This approach avoids then the introduction of a scalar-field potential that might be ill defined (not single valued). In order to explicitly show the usefulness of this method, we focus on static and spherically symmetric spacetimes and deal with the recent controversy about the existence of extended relativistic objects in certain class of f(R) models.

Jaime, Luisa G. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-543, Mexico Distrito Federal 04510 (Mexico); Facultad de Ciencias, Universidad Nacional Autonoma de Mexico, Apartado Postal 50-542, Mexico Distrito Federal 04510 (Mexico); Patino, Leonardo [Facultad de Ciencias, Universidad Nacional Autonoma de Mexico, Apartado Postal 50-542, Mexico Distrito Federal 04510 (Mexico); Salgado, Marcelo [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-543, Mexico Distrito Federal 04510 (Mexico)

2011-01-15T23:59:59.000Z

350

Principal facts for gravity stations in the Darrough Known Geothermal Resource Area (KGRA), Nevada  

DOE Green Energy (OSTI)

The latitude, longitude, elevation, observed gravity, theoretical gravity, terrain correction, free-air correction, Bougner correction, and Bougner anomaly are tabulated for 71 gravity stations in the Darrough KGRA, Nevada area. (WHK)

Peterson, D.L.; Dansereau, D.A.

1976-01-01T23:59:59.000Z

351

Principal facts for a gravity survey of Summer Lake Known Geothermal Resource Area, Oregon  

DOE Green Energy (OSTI)

Gravity survey data are tabulated for 73 stations. Site latitude, longitude, elevation, observed gravity, theoretical gravity, free-air correction, Bouguer correction, and the simple Bouguer anomaly are included. (WHK)

Peterson, D.L.; Meyer, R.F.

1976-01-01T23:59:59.000Z

352

Cosmography of f(R) gravity  

E-Print Network (OSTI)

It is nowadays accepted that the universe is undergoing a phase of accelerated expansion as tested by the Hubble diagram of Type Ia Supernovae (SNeIa) and several LSS observations. Future SNeIa surveys and other probes will make it possible to better characterize the dynamical state of the universe renewing the interest in cosmography which allows a model independent analysis of the distance - redshift relation. On the other hand, fourth order theories of gravity, also referred to as $f(R)$ gravity, have attracted a lot of interest since they could be able to explain the accelerated expansion without any dark energy. We show here how it is possible to relate the cosmographic parameters (namely the deceleration $q_0$, the jerk $j_0$, the snap $s_0$ and the lerk $l_0$ parameters) to the present day values of $f(R)$ and its derivatives $f^{(n)}(R) = d^nf/dR^n$ (with $n = 1, 2, 3$) thus offering a new tool to constrain such higher order models. Our analysis thus offers the possibility to relate the model independ...

Capozziello, S; Salzano, V

2008-01-01T23:59:59.000Z

353

Cosmography of f(R) gravity  

E-Print Network (OSTI)

It is nowadays accepted that the universe is undergoing a phase of accelerated expansion as tested by the Hubble diagram of Type Ia Supernovae (SNeIa) and several LSS observations. Future SNeIa surveys and other probes will make it possible to better characterize the dynamical state of the universe renewing the interest in cosmography which allows a model independent analysis of the distance - redshift relation. On the other hand, fourth order theories of gravity, also referred to as $f(R)$ gravity, have attracted a lot of interest since they could be able to explain the accelerated expansion without any dark energy. We show here how it is possible to relate the cosmographic parameters (namely the deceleration $q_0$, the jerk $j_0$, the snap $s_0$ and the lerk $l_0$ parameters) to the present day values of $f(R)$ and its derivatives $f^{(n)}(R) = d^nf/dR^n$ (with $n = 1, 2, 3$) thus offering a new tool to constrain such higher order models. Our analysis thus offers the possibility to relate the model independent results coming from cosmography to the theoretically motivated assumptions of $f(R)$ cosmology.

S. Capozziello; V. F. Cardone; V. Salzano

2008-02-12T23:59:59.000Z

354

Vacuum energy: quantum hydrodynamics vs quantum gravity  

E-Print Network (OSTI)

We compare quantum hydrodynamics and quantum gravity. They share many common features. In particular, both have quadratic divergences, and both lead to the problem of the vacuum energy, which in the quantum gravity transforms to the cosmological constant problem. We show that in quantum liquids the vacuum energy density is not determined by the quantum zero-point energy of the phonon modes. The energy density of the vacuum is much smaller and is determined by the classical macroscopic parameters of the liquid including the radius of the liquid droplet. In the same manner the cosmological constant is not determined by the zero-point energy of quantum fields. It is much smaller and is determined by the classical macroscopic parameters of the Universe dynamics: the Hubble radius, the Newton constant and the energy density of matter. The same may hold for the Higgs mass problem: the quadratically divergent quantum correction to the Higgs potential mass term is also cancelled by the microscopic (trans-Planckian) degrees of freedom due to thermodynamic stability of the whole quantum vacuum.

G. E. Volovik

2005-05-20T23:59:59.000Z

355

Constraint structure of the three dimensional massive gravity  

Science Conference Proceedings (OSTI)

Constraint analysis of the three-dimensional massive gravity, the so-called new massive gravity, is studied in the Palatini formalism. We show that amongst 6 components of the metric, 2 are dynamical, which is compatible with the existence of one vector massive graviton in the linearized theory (Fierz-Pauli theory).

Sadegh, M.; Shirzad, A. [Department of Physics, Isfahan University of Technology , P.O.Box 84156-83111, Isfahan (Iran, Islamic Republic of); School of Physics, Institute for Research in Fundamental Sciences (IPM), P.O.Box 19395-5531, Tehran (Iran, Islamic Republic of)

2011-04-15T23:59:59.000Z

356

Constraints on Dark Energy Models from Weak Gravity Conjecture  

E-Print Network (OSTI)

We study the constraints on the dark energy model with constant equation of state parameter $w=p/\\rho$ and the holographic dark energy model by using the weak gravity conjecture. The combination of weak gravity conjecture and the observational data gives $wenergy model realized by a scalar field is in swampland.

Chen, Ximing; Gong, Yungui

2008-01-01T23:59:59.000Z

357

Constraints on Dark Energy Models from Weak Gravity Conjecture  

E-Print Network (OSTI)

We study the constraints on the dark energy model with constant equation of state parameter $w=p/\\rho$ and the holographic dark energy model by using the weak gravity conjecture. The combination of weak gravity conjecture and the observational data gives $wenergy model realized by a scalar field is in swampland.

Ximing Chen; Jie Liu; Yungui Gong

2008-06-15T23:59:59.000Z

358

Walking in simulated reduced gravity: mechanical energy fluctuations and exchange  

E-Print Network (OSTI)

Walking in simulated reduced gravity: mechanical energy fluctuations and exchange TIMOTHY M reduced gravity: mechanical energy fluctuations and exchange. J. Appl. Physiol. 86(1): 383­390, 1999.--Walking humans conserve mechanical and, presum- ably, metabolic energy with an inverted pendulum-like ex

Kram, Rodger

359

A note on positive energy of topologically massive gravity  

E-Print Network (OSTI)

I review how "classical SUGRA" embeddability establishes positive energy E for D=3 topologically massive gravity (TMG), with or without a cosmological term, a procedure familiar from D=4 Einstein gravity (GR). It also provides explicit expressions for E. In contrast to GR, E is not manifestly positive, due to the peculiar two-term nature of TMG.

Deser, S

2009-01-01T23:59:59.000Z

360

Gravity Waves in Shear and Implications for Organized Convection  

Science Conference Proceedings (OSTI)

It is known that gravity waves in the troposphere, which are often excited by preexisting convection, can favor or suppress the formation of new convection. Here it is shown that in the presence of wind shear or barotropic wind, the gravity waves ...

Samuel N. Stechmann; Andrew J. Majda

2009-09-01T23:59:59.000Z

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361

Gravity on a Dilatonic Gauss-Bonnet Brane World  

E-Print Network (OSTI)

The effective four-dimensional, linearised gravity of a Randall-Sundrum-like brane world model is analysed. The model includes higher order curvature terms (such as the Gauss-Bonnet term) and a scalar field. The resulting brane worlds can have better agreement with observations than the equivalent Einstein gravity models.

Stephen C. Davis

2004-08-18T23:59:59.000Z

362

Three?dimensional group manifold reductions of gravity  

Science Conference Proceedings (OSTI)

We review the three?dimensional group manifold reductions of pure Einstein gravity and we exhibit a new consistent group manifold reduction of gravity when the compactification group manifold is S 3. The new reduction leads to a lower dimensional theory whose gauge group is SU (2).

Román Linares

2005-01-01T23:59:59.000Z

363

Modeling the Hydrological Effect on Local Gravity at Moxa, Germany  

Science Conference Proceedings (OSTI)

A superconducting gravimeter has observed with high accuracy (to within a few nm s?2) and high frequency (1 Hz) the temporal variations in the earth’s gravity field near Moxa, Germany, since 1999. Hourly gravity residuals are obtained by time ...

Shaakeel Hasan; Peter A. Troch; J. Boll; C. Kroner

2006-06-01T23:59:59.000Z

364

Quantum Corrections to Newton's Law in Resummed Quantum Gravity  

E-Print Network (OSTI)

We present the elements of resummed quantum gravity, a new approach to quantum gravity based on the work of Feynman using the simplest example of a scalar field as the representative matter. We show that we get a UV finite quantum correction to Newton's law.

B. F. L. Ward

2004-11-03T23:59:59.000Z

365

COMPUTER SIMULATION OF SINGLE-WELL STEAM ASSISTED GRAVITY DRAINAGE  

E-Print Network (OSTI)

COMPUTER SIMULATION OF SINGLE-WELL STEAM ASSISTED GRAVITY DRAINAGE (SW-SAGD) TR 119 By Keith T of Sensitivity Analysis Cases 32 #12;v List of Figures Figure 1: Steam Assisted Gravity Drainage Concept: Recovery Factor vs. Time for All Cases (10 Years Production) 13 Figure 8: Cumulative Steam-Oil Ratio vs

366

Gravity base, jack-up platform - method and apparatus  

SciTech Connect

The invention relates to an offshore, gravity base, jack-up platform comprising a deck, a gravity base and one or more legs interconnecting the deck and base. The gravity base comprises a generally polygonal shaped, monolithic hull structure with reaction members extending downwardly from the hull to penetrate the waterbed and react to vertical and lateral loads imposed upon the platform while maintaining the gravity hull in a posture elevated above the surface of the waterbed. A method aspect of the invention includes the steps of towing a gravity base, jack-up platform, as a unit, to a preselected offshore site floating upon the gravity hull. During the towing operation, the deck is mounted adjacent the gravity base with a leg or legs projecting through the deck. At a preselected offshore station ballast is added to the gravity base and the platform descends slightly to a posture where the platform is buoyantly supported by the deck. The base is then jacked down toward the seabed and the platform is laterally brought onto station. Ballast is then added to the deck and the reaction members are penetrated into the waterbed to operational soil refusal. Ballast is then ejected from the deck and the deck is jacked to an operational elevation above a predetermined statistical wave crest height.

Herrmann, R.P.; Pease, F.T.; Ray, D.R.

1981-05-05T23:59:59.000Z

367

Ground Gravity Survey At Maui Area (DOE GTP) | Open Energy Information  

Open Energy Info (EERE)

Ground Gravity Survey At Maui Area (DOE GTP) Exploration Activity Details Location Maui Area Exploration Technique Ground Gravity Survey Activity Date Usefulness not indicated...

368

Aeromagnetic and gravity surveys in the Coso Range, California | Open  

Open Energy Info (EERE)

and gravity surveys in the Coso Range, California and gravity surveys in the Coso Range, California Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Aeromagnetic and gravity surveys in the Coso Range, California Details Activities (2) Areas (1) Regions (0) Abstract: The effect of an underlying magma reservoir cannot be identified within the complex gravity pattern in the Coso Range, California. Rather, linear gravity contours, which suggest a regional tectonic origin, enclose the location of most of the volcanic activity of the Coso Range. Faults along the edges of northwest trending, magnetic blocks probably provided paths of minimum resistance to the ascending viscous magma that was extruded as rhyolite domes. Dense, magnetic rocks associated with a complex mafic pluton 9 km in diameter form a relatively impermeable north border of

369

Generalized Misner-Sharp Energy in f(R) Gravity  

E-Print Network (OSTI)

We study generalized Misner-Sharp energy in $f(R)$ gravity in a spherically symmetric spacetime. We find that unlike the cases of Einstein gravity and Gauss-Bonnet gravity, the existence of the generalized Misner-Sharp energy depends on a constraint condition in the $f(R)$ gravity. When the constraint condition is satisfied, one can define a generalized Misner-Sharp energy, but it cannot always be written in an explicit quasi-local form. However, such a form can be obtained in a FRW universe and for static spherically symmetric solutions with constant scalar curvature. In the FRW universe, the generalized Misner-Sharp energy is nothing but the total matter energy inside a sphere with radius $r$, which acts as the boundary of a finite region under consideration. The case of scalar-tensor gravity is also briefly discussed.

Cai, Rong-Gen; Hu, Ya-Peng; Ohta, Nobuyoshi

2009-01-01T23:59:59.000Z

370

Non-trivial 2+1-Dimensional Gravity  

E-Print Network (OSTI)

We analyze 2+1-dimensional gravity in the framework of quantum gauge theory. We find that Einstein gravity has a trivial physical subspace which reflects the fact that the classical solution in empty space is flat. Therefore we study massive gravity which is not trivial. In the limit of vanishing graviton mass we obtain a non-trivial massless theory different from Einstein gravity. We derive the interaction from descent equations and obtain the cosmological topologically massive gravity. However, in addition to Einstein and Chern-Simons coupling we need coupling to fermionic ghost and anti-ghost fields and to a vector-graviton field with the same mass as the graviton.

D. R. Grigore; G. Scharf

2010-08-07T23:59:59.000Z

371

Wavenumber–Frequency Spectra of Inertia–Gravity and Mixed Rossby–Gravity Waves in the Equatorial Pacific Ocean  

Science Conference Proceedings (OSTI)

In the 1970s and 1980s, there was considerable interest in near-equatorial variability at periods of days to weeks associated with oceanic equatorial inertia–gravity waves and mixed Rossby–gravity waves. At that time, the measurements available ...

J. Thomas Farrar; Theodore S. Durland

2012-11-01T23:59:59.000Z

372

Gravity Waves in a Horizontal Shear Flow. Part II: Interaction between Gravity Waves and Potential Vorticity Perturbations  

E-Print Network (OSTI)

Interaction among potential vorticity perturbations and propagating internal gravity waves in a horizontally sheared zonal flow is investigated. In the strong stratification limit, an initial vorticity perturbation weakly excites two propagating gravity waves while the density component of the potential vorticity perturbation is significantly amplified, potentially leading to convective collapse. If stratification is sufficiently weak, a strong coupling between vorticity perturbations and gravity waves is found and spontaneous gravity wave generation occurs. This coupling can be traced to the nonnormal interaction between the potential vorticity and gravity wave manifolds in the weak stratification limit. Vorticity perturbations amplify in energy due to downgradient Reynolds stress when their phase lines tilt against the shear and the large growth attained is transferred to propagating gravity waves. When the flow geometry is such that the excited gravity waves are confined in the vicinity of the vorticity perturbation by their trapping levels, an overall convective collapse of this region can be anticipated. On the other hand, when the flow geometry permits wave propagation, significant gravity wave emission occurs. 1.

Nikolaos A. Bakas; Brian; F. Farrell

2007-01-01T23:59:59.000Z

373

The great American garage  

E-Print Network (OSTI)

How does one explore the suburban home? Go in through the garage, of course. Sales, bands, suicides, and business startups: The suburban garage is the most culturally flexible space in the entire American domestic environment. ...

Miller, B. Alex (Brian Alex), 1977-

2004-01-01T23:59:59.000Z

374

American Samoa- Net Metering  

Energy.gov (U.S. Department of Energy (DOE))

The American Samoa Power Authority (ASPA), a government-owned electric utility, is the only power provider in this U.S. territory of almost 70,000 people. ASPA's "Interconnection and Net Energy...

375

Semiclassical approximation to supersymmetric quantum gravity  

SciTech Connect

We develop a semiclassical approximation scheme for the constraint equations of supersymmetric canonical quantum gravity. This is achieved by a Born-Oppenheimer type of expansion, in analogy to the case of the usual Wheeler-DeWitt equation. The formalism is only consistent if the states at each order depend on the gravitino field. We recover at consecutive orders the Hamilton-Jacobi equation, the functional Schroedinger equation, and quantum gravitational correction terms to this Schroedinger equation. In particular, the following consequences are found: (i) the Hamilton-Jacobi equation and therefore the background spacetime must involve the gravitino, (ii) a (many-fingered) local time parameter has to be present on super Riem {sigma} (the space of all possible tetrad and gravitino fields) (iii) quantum supersymmetric gravitational corrections affect the evolution of the very early Universe. The physical meaning of these equations and results, in particular, the similarities to and differences from the pure bosonic case, are discussed.

Kiefer, Claus; Lueck, Tobias; Moniz, Paulo [Institut fuer Theoretische Physik, Universitaet zu Koeln, Zuelpicher Strasse 77, 50937 Cologne (Germany); Astronomy Unit, School of Mathematical Sciences, Queen Mary College, University of London, Mile End Road, London E1 4NS (United Kingdom)

2005-08-15T23:59:59.000Z

376

Hydrodynamic orienting of asymmetric microobjects under gravity  

E-Print Network (OSTI)

It is shown that nonsymmetric microobjects orient while settling under gravity in a viscous fluid. To analyze this process, a simple shape is chosen: a non-deformable `chain'. The chain consists of two straight arms, made of touching solid spheres. In the absence of external torques, the spheres are free to spin along the arms. The motion of the chain is evaluated by solving the Stokes equations with the use of the multipole method. It is demonstrated that the spinning beads speed up sedimentation by a small amount, and increase the orientation rate significantly in comparison to the corresponding rigid chain. It is shown that chains orient towards the V-shaped stable stationary configuration. In contrast, rods and star-shaped microobjects do not rotate. The hydrodynamic orienting is relevant for efficient swimming of non-symmetric microobjects, and for sedimenting suspensions.

Maria L. Ekiel-Jezewska; Eligiusz Wajnryb

2008-12-12T23:59:59.000Z

377

Yang-Mills Gravity in Biconformal Space  

E-Print Network (OSTI)

We propose a new conformal supergravity model with direct relevance to string/gauge theory dualities. This biconformal supergravity theory is formulated with a Yang-Mills type action. The resulting 8-dim symplectic geometries describe 4-dim scale-invariant general relativity. We then show an extension of N = 4 SUSY Yang-Mills to a curved biconformal geometry such that the extended form of the Yang-Mills fields provides the curvatures for the biconformal space. These curvatures solve the biconformal field equations whenever the original 4-dim fields satisfy the 4-dim YM theory. This gives a 1-1 mapping between the gravity and gauge theories. We also display systematic extension of any spacetime co-tangent bundle to a biconformal space, and extension of any 4-dim Yang-Mills theory to an equivalent theory on that space. 1

Lara B. Anderson; James T. Wheeler

2008-01-01T23:59:59.000Z

378

Solar system tests of Ho?ava-Lifshitz gravity  

E-Print Network (OSTI)

Recently, a renormalizable gravity theory with higher spatial derivatives in four dimensions was proposed by Ho\\v{r}ava. The theory reduces to Einstein gravity with a non-vanishing cosmological constant in IR, but it has improved UV behaviors. The spherically symmetric black hole solutions for an arbitrary cosmological constant, which represent the generalization of the standard Schwarzschild-(A)dS solution, has also been obtained for the Ho\\v{r}ava-Lifshitz theory. The exact asymptotically flat Schwarzschild type solution of the gravitational field equations in Ho\\v{r}ava gravity contains a quadratic increasing term, as well as the square root of a fourth order polynomial in the radial coordinate, and it depends on one arbitrary integration constant. The IR modified Ho\\v{r}ava gravity seems to be consistent with the current observational data, but in order to test its viability more observational constraints are necessary. In the present paper we consider the possibility of observationally testing Ho\\v{r}ava gravity at the scale of the Solar System, by considering the classical tests of general relativity (perihelion precession of the planet Mercury, deflection of light by the Sun and the radar echo delay) for the spherically symmetric black hole solution of Ho\\v{r}ava-Lifshitz gravity. All these gravitational effects can be fully explained in the framework of the vacuum solution of the gravity. Moreover, the study of the classical general relativistic tests also constrain the free parameter of the solution.

Tiberiu Harko; Zoltan Kovács; Francisco S. N. Lobo

2009-08-20T23:59:59.000Z

379

Massive gravity with mass term in three dimensions  

Science Conference Proceedings (OSTI)

We analyze the effect of the Pauli-Fierz mass term on a recently established, new massive gravity theory in three space-time dimensions. We show that the Pauli-Fierz mass term makes the new massive gravity theory nonunitary. Moreover, although we add the gravitational Chern-Simons term to this model, the situation remains unchanged and the theory stays nonunitary despite that the structure of the graviton propagator is greatly changed. Thus, the Pauli-Fierz mass term is not allowed to coexist with mass-generating higher-derivative terms in the new massive gravity.

Nakasone, Masashi; Oda, Ichiro [Department of Physics, Faculty of Science, University of the Ryukyus, Nishihara, Okinawa 903-0213 (Japan)

2009-05-15T23:59:59.000Z

380

How to Distinguish Dark Energy and Modified Gravity?  

E-Print Network (OSTI)

The current accelerated expansion of our universe could be due to an unknown energy component (dark energy) or a modification to general relativity (modified gravity). It is proposed in literature that combining the probes of cosmic expansion history and growth history can distinguish between dark energy and modified gravity. In the present work, we show that the possible interaction between dark energy and dark matter could make interacting dark energy model and modified gravity model indistinguishable. An explicit example is also given. Therefore, it is required to seek some complementary probes beyond the ones of cosmic expansion history and growth history.

Wei, Hao

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gravity astm american" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Energy conditions in $f(R,L_{m})$ gravity  

E-Print Network (OSTI)

In order to constrain $f(R,L_{m})$ gravity from theoretical aspects, its energy conditions are derived in this paper. These energy conditions given by us are quite general and can be degenerated to the well-known energy conditions in General Relativity and $f(R)$ theories of gravity with arbitrary coupling, non-minimal coupling and non-coupling between matter and geometry, respectively, as special cases. To exemplify how to use these energy conditions to restrict $f(R,L_{m})$ gravity, we consider a special model in the FRW cosmology and give some corresponding results by using astronomical observations.

Wang, Jun

2012-01-01T23:59:59.000Z

382

Strong Energy Condition in $R + R^2$ Gravity  

E-Print Network (OSTI)

In this paper, we study Raychaudhuri's equation in the background of $R + \\beta R^2$ gravity with a phenomenological matter ($\\rho \\propto a(t)^{-n}$). We conclude that even though the Strong Energy Condition (S.E.C.) for Einstein's gravity, which guarantees singularity, is $n\\geq 2$ for $\\rho \\propto a(t)^{-n}$, a perturbative analysis of Raychaudhuri's equation in the background of $R + \\beta R^2$ gravity reveals that the big bang singularity may not be guaranteed for $n > 4$. We derive the following Strong Energy Conditions for $R + \\beta R^2$ ($\\beta \

J. H. Kung

1995-10-04T23:59:59.000Z

383

Gravity Effects on Information Filtering and Network Evolving  

E-Print Network (OSTI)

In this Letter, based on the gravity principle of classical physics, we propose a tunable gravity-based model, which considers tag usage pattern to weigh both the mass and distance of network nodes. We then apply this model in solving the problems of information filtering and network evolving. Experimental results on two real-world data sets, Del.icio.us and MovieLens, show that it can not only enhance the algorithmic performance, but also can better characterize the properties of real networks. This work may shed some light on the in-depth understanding the gravity effect

Liu, Jin-Hu; Yang, Chengcheng; Chen, Lingjiao; Liu, Chuang; Wang, Xueqi

2013-01-01T23:59:59.000Z

384

Gravity inversion using a binary formulation Richard A. Krahenbuhl* and Yaoguo Li  

E-Print Network (OSTI)

Gravity inversion using a binary formulation Richard A. Krahenbuhl* and Yaoguo Li Gravity contrast that gives rise to zero gravity response on the surface. As a result, part of the salt structure structure using gravity data can be divided into two general categories. The first are interface inversions

385

Gravity observations and 3D structure of the Earth , F. Chambat  

E-Print Network (OSTI)

1 Gravity observations and 3D structure of the Earth Y. Ricard1 , F. Chambat Laboratoire des, Michigan-Ann Harbor University, USA. Short title: GRAVITY OBSERVATIONS AND 3D STRUCTURE OF THE EARTH 1. The determination of Earth's gravity field has benefited from various gravity missions that have been launched

386

Critical gravity as van Dam-Veltman-Zakharov discontinuity in anti de Sitter space  

E-Print Network (OSTI)

We consider critical gravity as van Dam-Vletman-Zakharov (vDVZ) discontinuity in anti de Sitter space. For this purpose, we introduce the higher curvature gravity. This discontinuity can be confirmed by calculating the residues of relevant poles explicitly. For the non-critical gravity of $0gravity.

Yun Soo Myung

2011-07-18T23:59:59.000Z

387

American College of Internal Medicine  

E-Print Network (OSTI)

, gravity, and surface tension.16,17 First, a metal wire, such as tungsten or platinum/iridium had resistor in order to reduce the damage to the tip. Unfortunately, most metal tips take dam- age during

Taylor, Jerry

388

Ground Gravity Survey At Mokapu Penninsula Area (Thomas, 1986) | Open  

Open Energy Info (EERE)

Ground Gravity Survey At Mokapu Penninsula Area Ground Gravity Survey At Mokapu Penninsula Area (Thomas, 1986) Exploration Activity Details Location Mokapu Penninsula Area Exploration Technique Ground Gravity Survey Activity Date Usefulness not indicated DOE-funding Unknown Notes A separate geophysical analysis performed on the Koolau caldera area (Kauahikaua, 1981 a) synthesized existing self-potential, gravity, seismic and aeromagnetic data with recently acquired resistivity soundings. An analysis of the observed remnant magnetization within the caldera complex suggested that subsurface temperatures ranged from less than 300degrees C to no more than 540degrees C. The resistivity data indicated that the electrical basement, to a depth of 900 m, had resistivities ranging from 42 ohm.m to more than 1000 ohm.m, which is considered to be within the

389

The Optimal State for Gravity Currents in Shear  

Science Conference Proceedings (OSTI)

This study examines the lifting of sheared environmental air by gravity currents, focusing primarily on the theoretical “optimal state” in which near-surface flow is turned into a vertically oriented jet. Theoretical models are presented from ...

George H. Bryan; Richard Rotunno

390

"Detuned" f(R) gravity and dark energy  

E-Print Network (OSTI)

In gravity theories derived from a f(R) Lagrangian, matter is usually supposed to be minimally coupled to the metric, which hence defines a ``Jordan frame.'' However, since the field equations are fourth order, gravity possesses an extra degree of freedom on top of the standard graviton, as is manifest from its equivalent description in the conformally related, Einstein, frame. We introduce explicitly this extra scalar degree of freedom in the action and couple it to matter, so that the original metric no longer defines a Jordan frame. This ``detuning'' puts f(R) gravity into a wider class of scalar--tensor theories. We argue that a ``chameleon-like'' detuning tracing the background matter density may provide purely gravitational models which account for the present acceleration of the universe and evade local gravity constraints.

Nathalie Deruelle; Misao Sasaki; Yuuiti Sendouda

2008-03-19T23:59:59.000Z

391

HF Doppler Measurements of Mesospheric Gravity Wave Momentum Fluxes  

Science Conference Proceedings (OSTI)

Recent theoretical studies have emphasized the probable importance of internal gravity waves in balancing the momentum budget of the mesosphere. In this paper, we propose a method by which the vertical flux of horizontal momentum can be measured ...

R. A. Vincent; I. M. Reid

1983-05-01T23:59:59.000Z

392

Tracking Gravity Waves in Baroclinic Jet-Front Systems  

Science Conference Proceedings (OSTI)

Using a two-dimensional Fourier decomposition and a four-dimensional ray-tracing technique, the propagating characteristics and source mechanisms of mesoscale gravity waves simulated in idealized baroclinic jet-front systems are investigated. The ...

Yonghui Lin; Fuqing Zhang

2008-07-01T23:59:59.000Z

393

Gravity Wave Generation by a Three-Dimensional Thermal Forcing  

Science Conference Proceedings (OSTI)

Thermal forcing is one of the mechanisms of wave generation in convection. Although it does not account for all the wave generation mechanisms, thermal forcing is a good proxy for estimating the gravity wave spectrum forced by convection. This ...

Jadwiga H. Beres

2004-07-01T23:59:59.000Z

394

Costs of Imported Crude Oil by API Gravity  

Annual Energy Outlook 2012 (EIA)

EIA-856, "Monthly Foreign Crude Oil Acquisition Report," July 1984 to present. 26. F.O.B. Costs of Imported Crude Oil by API Gravity 48 Energy Information Administration ...

395

Spectra of Baroclinic Inertia-Gravity Wave Turbulence  

Science Conference Proceedings (OSTI)

Baroclinic inertia–gravity (IG) waves form a persistent background of thermocline depth and sea surface height oscillations. They also contribute to the kinetic energy of horizontal motions in the subsurface layer. Measured by the ratio of water ...

Roman E. Glazman

1996-07-01T23:59:59.000Z

396

Small effects of low-energy quantum gravity  

E-Print Network (OSTI)

Small effects of quantum gravity on the scale $\\sim 10^{-3} eV$ and their cosmological consequences are discussed and compared with observations of supernovae 1a, gamma-ray bursts and galaxies.

Ivanov, Michael A

2007-01-01T23:59:59.000Z

397

A Model Study of Gravity Waves over Hurricane Humberto (2001)  

Science Conference Proceedings (OSTI)

Atmospheric gravity waves are known to influence global circulations. Understanding these waves and their sources help to develop parameterizations that include their effects in climate and weather forecasting models. Deep convection is believed ...

M. A. Kuester; M. J. Alexander; E. A. Ray

2008-10-01T23:59:59.000Z

398

Reconstructing $f(R,T)$ gravity from holographic dark energy  

E-Print Network (OSTI)

We numerically reconstruct those $f(R,T)$ theories of gravity (where $T$ is the trace of the energy-momentum tensor) which are able to reproduce holographic dark energy models.

Houndjo, M J S

2011-01-01T23:59:59.000Z

399

Explicitly Stochastic Parameterization of Nonorographic Gravity Wave Drag  

Science Conference Proceedings (OSTI)

A straightforward methodology is presented for converting the deterministic multiwave parameterizations of nonorographic gravity wave drag, currently used in general circulation models (GCMs), to stochastic analogs that use fewer waves (in the ...

Stephen D. Eckermann

2011-08-01T23:59:59.000Z

400

Reduced Gravity Education Flight Opportunity for Students at...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

experiment flights to produce periods of weightlessness and hypergravity ranging from 0 gravity, or g, to 2 g. Proposals are due April 17, 2013. All applicants must be full-time...

Note: This page contains sample records for the topic "gravity astm american" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Quasi-Local Energy in Loop Quantum Gravity  

E-Print Network (OSTI)

Although there is no known meaningful notion of the energy density of the gravitational field in general relativity, a few notions of quasi-local energy of gravity associated to extended but finite domains have been proposed. In this paper, the notions of quasi-local energy are studied in the framework of loop quantum gravity, in order to see whether these notions can be carried out at quantum level. Two basic quasi-local geometric quantities are quantized, which lead to well-defined operators in the kinematical Hilbert space of loop quantum gravity. We then use them as basic building blocks to construct different versions of quasi-local energy operators. The operators corresponding to Brown-York energy, Liu-Yau energy, Hawking energy, and Geroch energy are obtained respectively. The virtue of the Geroch energy operator is beneficial for us to derive a rather general entropy-area relation and thus a holographic principle from loop quantum gravity.

Jinsong Yang; Yongge Ma

2008-12-18T23:59:59.000Z

402

On the Equilibrium Spectrum of Gravity – Capillary Waves  

Science Conference Proceedings (OSTI)

The equilibrium spectra of unidirectional gravity – capillary waves are derived from the wave-action balance equation. The calculations include nonlinear triad interactions, direct energy input from the wind, and viscous dissipation. Known ...

Michael Stiassnie

1996-06-01T23:59:59.000Z

403

Quasi-Local Energy in Loop Quantum Gravity  

E-Print Network (OSTI)

Although there is no known meaningful notion of the energy density of the gravitational field in general relativity, a few notions of quasi-local energy of gravity associated to extended but finite domains have been proposed. In this paper, the notions of quasi-local energy are studied in the framework of loop quantum gravity, in order to see whether these notions can be carried out at quantum level. Two basic quasi-local geometric quantities are quantized, which lead to well-defined operators in the kinematical Hilbert space of loop quantum gravity. We then use them as basic building blocks to construct different versions of quasi-local energy operators. The operators corresponding to Brown-York energy, Liu-Yau energy, Hawking energy, and Geroch energy are obtained respectively. The virtue of the Geroch energy operator is beneficial for us to derive a rather general entropy-area relation from loop quantum gravity.

Yang, Jinsong

2008-01-01T23:59:59.000Z

404

Ghost dark energy in $f(R)$ model of gravity  

E-Print Network (OSTI)

We study a correspondence between $f(R)$ model of gravity and a phenomenological kind of dark energy (DE), which is known as QCD ghost dark energy. Since this kind of dark energy is not stable in the context of Einsteinian theory of gravity and Brans-Dicke model of gravity, we consider two kinds of correspondence between modified gravity and DE. By studding the dynamical evolution of model and finding relevant quantities such as, equation of state parameter, deceleration parameter, dimensionless density parameter, we show that the model can describe the present Universe and also the EoS parameter can cross the phantom divide line without needs to any kinetic energy with negative sign. Furthermore, by obtaining the adiabatic squared sound speed of the model for different cases of interaction, we show that this model is stable.

Saaidi, Kh; Sabet, B

2012-01-01T23:59:59.000Z

405

Stratospheric Gravity Waves Generated by Multiscale Tropical Convection  

Science Conference Proceedings (OSTI)

The generation of gravity waves by multiscale cloud systems evolving in an initially motionless and thermodynamically uniform environment is explored using a two-dimensional cloud-system-resolving model. The simulated convection has similar depth ...

Todd P. Lane; Mitchell W. Moncrieff

2008-08-01T23:59:59.000Z

406

Field Verification of ADCP Surface Gravity Wave Elevation Spectra  

Science Conference Proceedings (OSTI)

Acoustic Doppler current profilers (ADCPs) can measure orbital velocities induced by surface gravity waves, yet the ADCP estimates of these velocities are subject to a relatively high noise level. The present paper introduces a linear filtration ...

A. J. F. Hoitink; H. C. Peters; M. Schroevers

2007-05-01T23:59:59.000Z

407

An Upper Gravity-Wave Absorbing Layer for NWP Applications  

Science Conference Proceedings (OSTI)

Although the use of a damping layer near the top of a computational model domain has proven effective in absorbing upward-propagating gravity-wave energy in idealized simulations, this technique has been less successful in real atmospheric ...

J. B. Klemp; J. Dudhia; A. D. Hassiotis

2008-10-01T23:59:59.000Z

408

Secondary Instabilities in Breaking Inertia–Gravity Waves  

Science Conference Proceedings (OSTI)

The three-dimensionalization of turbulence in the breaking of nearly vertically propagating inertia–gravity waves is investigated numerically using singular vector analysis applied to the Boussinesq equations linearized about three two-dimensional ...

Mark D. Fruman; Ulrich Achatz

2012-01-01T23:59:59.000Z

409

Do Gravity Waves Transport Angular Momentum away from Tropical Cyclones?  

Science Conference Proceedings (OSTI)

Previous studies have suggested that gravity waves can transport a significantly large amount of angular momentum away from tropical cyclones, as much as 10% of the core angular momentum per hour. These previous studies used the shallow-water ...

Yumin Moon; David S. Nolan

2010-01-01T23:59:59.000Z

410

Gravity Waves Generated by Sheared Potential Vorticity Anomalies  

Science Conference Proceedings (OSTI)

The gravity waves (GWs) generated by potential vorticity (PV) anomalies in a rotating stratified shear flow are examined under the assumptions of constant vertical shear, two-dimensionality, and unbounded domain. Near a PV anomaly, the associated ...

François Lott; Riwal Plougonven; Jacques Vanneste

2010-01-01T23:59:59.000Z

411

Mechanisms for Spontaneous Gravity Wave Generation within a Dipole Vortex  

Science Conference Proceedings (OSTI)

Previous simulations of dipole vortices propagating through rotating, stratified fluid have revealed small-scale inertia–gravity waves that are embedded within the dipole near its leading edge and are approximately stationary relative to the ...

Chris Snyder; Riwal Plougonven; David J. Muraki

2009-11-01T23:59:59.000Z

412

Precision gravity studies at Cerro Prieto: the second year  

DOE Green Energy (OSTI)

Precision gravity measurements were initiated at Cerro Prieto in 1978. Interpretation of the first annual repetition of the measurements is presented. Field procedures, data reduction, and data interpretation are reviewed briefly. (MHR)

Grannell, R.B.; Tarman, D.W.; Clover, R.C.; Leggewie, R.M.; Aronstam, P.S.; Kroll, R.C.; Eppink, J.

1980-02-01T23:59:59.000Z

413

Geometry of loop quantum gravity on a graph  

SciTech Connect

We discuss the meaning of geometrical constructions associated to loop quantum gravity states on a graph. In particular, we discuss the 'twisted geometries' and derive a simple relation between these and Regge geometries.

Rovelli, Carlo; Speziale, Simone [Centre de Physique Theorique, CNRS-Luminy Case 907, 13288 Marseille Cedex 09 (France)

2010-08-15T23:59:59.000Z

414

Gravity as Archimedes' thrust and a bifurcation in that theory  

E-Print Network (OSTI)

Euler's interpretation of Newton's gravity (NG) as Archimedes' thrust in a fluid ether is presented in some detail. Then a semi-heuristic mechanism for gravity, close to Euler's, is recalled and compared with the latter. None of these two "gravitational ethers" can obey classical mechanics. This is logical since the ether defines the very reference frame, in which mechanics is defined. This concept is used to build a scalar theory of gravity: NG corresponds to an incompressible ether, a compressible ether leads to gravitational waves. In the Lorentz-Poincar\\'e version, special relativity is compatible with the ether, but, with the heterogeneous ether of gravity, it applies only locally. A correspondence between metrical effects of uniform motion and gravitation is assumed, yet in two possible versions (one is new). Dynamics is based on a (non-trivial) extension of Newton's second law. The observational status for the theory with the older version of the correspondence is summarized.

Mayeul Arminjon

2004-04-21T23:59:59.000Z

415

Global Gravity Wave Variances from Aura MLS: Characteristics and Interpretation  

Science Conference Proceedings (OSTI)

The gravity wave (GW)–resolving capabilities of 118-GHz saturated thermal radiances acquired throughout the stratosphere by the Microwave Limb Sounder (MLS) on the Aura satellite are investigated and initial results presented. Because the ...

Dong L. Wu; Stephen D. Eckermann

2008-12-01T23:59:59.000Z

416

The External and Internal shrinkages in Aluminum Gravity Castings  

Science Conference Proceedings (OSTI)

Presentation Title, The External and Internal shrinkages in Aluminum Gravity Castings. Author(s), Fu-Yuan Hsu, Shin-Wei Wang, Huey-Jiuan Lin. On-Site ...

417

Large Searching for Higher Dimensional Gravity with Neutron Experiments  

Science Conference Proceedings (OSTI)

N?dimensional gravity is analized in the context of recent work on “large” supplementary dimensions. A simple derivation of the compactification radii for additional dimensions in the universe is made

Alejandro Frank

2007-01-01T23:59:59.000Z

418

New Gravity Wave Treatments for GISS Climate Models  

E-Print Network (OSTI)

Previous versions of GISS climate models have either used formulations of Rayleigh drag to represent unresolved gravity wave interactions with the model-resolved flow or have included a rather complicated treatment of ...

Geller, Marvin A.

419

An Approach to Gravity Modification as a Propulsion Technology  

Science Conference Proceedings (OSTI)

Gravity modification as a portable non?mass effect is feasible. Contemporary experiments such as HFGW and LIGO require mass to model gravitational acceleration and gravitational waves. A different approach to gravitational acceleration

Benjamin T. Solomon

2009-01-01T23:59:59.000Z

420

Einstein gravity as a 3D conformally invariant theory  

E-Print Network (OSTI)

We give an alternative description of the physical content of general relativity that does not require a Lorentz invariant spacetime. Instead, we find that gravity admits a dual description in terms of a theory where local size is irrelevant. The dual theory is invariant under foliation preserving 3-diffeomorphisms and 3D conformal transformations that preserve the 3-volume (for the spatially compact case). Locally, this symmetry is identical to that of Horava-Lifshitz gravity in the high energy limit but our theory is equivalent to Einstein gravity. Specifically, we find that the solutions of general relativity, in a gauge where the spatial hypersurfaces have constant mean extrinsic curvature, can be mapped to solutions of a particular gauge fixing of the dual theory. Moreover, this duality is not accidental. We provide a general geometric picture for our procedure that allows us to trade foliation invariance for conformal invariance. The dual theory provides a new proposal for the theory space of quantum gravity.

Henrique Gomes; Sean Gryb; Tim Koslowski

2010-10-12T23:59:59.000Z

Note: This page contains sample records for the topic "gravity astm american" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

An Alternative Leapfrog Scheme for Surface Gravity Wave Equations  

Science Conference Proceedings (OSTI)

An alternative leapfrog scheme using a staggered time grid system is proposed to solve surface gravity wave equations. In addition to the nondissipative second-order accuracy scheme that is inherent in the standard leapfrog scheme, the ...

Weidong Zhou

2002-09-01T23:59:59.000Z

422

Cosmological phase space of R^n gravity  

E-Print Network (OSTI)

We present some exact solutions and a phase space analysis of metric $f(R)$-gravity models of the type $R^{n}$. We divide our discussion in $n\

Alejandro Aviles Cervantes; Jorge L. Cervantes-Cota

2009-01-23T23:59:59.000Z

423

Entrainment in Shallow Rotating Gravity Currents: A Modeling Study  

Science Conference Proceedings (OSTI)

The physics of shallow gravity currents passing through a rotating channel at subcritical Froude number is investigated here with a series of idealized numerical experiments. It is found that the combined effects of friction and rotation set up a ...

Lars Umlauf; Lars Arneborg; Richard Hofmeister; Hans Burchard

2010-08-01T23:59:59.000Z

424

Gravity Wave 1-leat Fluxes: A Lagrangian Approach  

Science Conference Proceedings (OSTI)

The effect of a vertically propagating, internal gravity wave on the vertical flux of potential temperature (heat) is considered by averaging the local heat flux vector over a potential temperature surface. This approach gives the wave heat flux ...

Lawrence Coy; David C. Fritts

1988-06-01T23:59:59.000Z

425

Time delays across saddles as a test of modified gravity  

E-Print Network (OSTI)

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 meters 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.

Joao Magueijo; Ali Mozaffari

2012-12-15T23:59:59.000Z

426

Gravity Waves Driven by Diurnal Fluctuations in Mesoscale Heating  

Science Conference Proceedings (OSTI)

Observed convective systems, such as mesoscale convective complexes (MCCs), often undergo repeated cycles of nocturnal growth and daytime decay especially during the summer. The gravity wave response to these pulsations is poorly understood. The ...

John H. E. Clark

1999-03-01T23:59:59.000Z

427

Numerical Modeling of Gravity Wave Generation by Deep Tropical Convection  

Science Conference Proceedings (OSTI)

Although convective clouds are known to generate internal gravity waves, the mechanisms responsible are not well understood. The present study seeks to clarify the dynamics of wave generation using a high-resolution numerical model of deep ...

Todd P. Lane; Michael J. Reeder; Terry L. Clark

2001-05-01T23:59:59.000Z

428

A Simple Test of the Initialization of Gravity Modes  

Science Conference Proceedings (OSTI)

The initialization schemes of Machenhauer (1977), Baer and Tribbia (1977), and one requiring the initial second time derivatives of gravity modes to be zero are tested by application to a simple differential equation, which partially simulates ...

Bradley A. Ballish

1981-06-01T23:59:59.000Z

429

Spontaneous Imbalance and Hybrid Vortex–Gravity Structures  

Science Conference Proceedings (OSTI)

After reviewing the background, this article discusses the recently discovered examples of hybrid propagating structures consisting of vortex dipoles and comoving gravity waves undergoing wave capture. It is shown how these examples fall outside ...

Michael E. McIntyre

2009-05-01T23:59:59.000Z

430

Gravity Currents in Confined Channels with Environmental Shear  

Science Conference Proceedings (OSTI)

This study examines properties of gravity currents in confined channels with sheared environmental flow. Under the assumptions of steady and inviscid flow, two-dimensional analytic solutions are obtained for a wide range of shear values. The slope ...

George H. Bryan; Richard Rotunno

431

Implications of the Hydrostatic Assumption on Atmospheric Gravity Waves  

Science Conference Proceedings (OSTI)

The validity of the hydrostatic approximation is examined for use in predicting the dynamics of topographically generated atmospheric gravity waves (lee waves) propagating in an atmosphere with realistic wind shear. To isolate nonhydrostatic ...

Teddie L. Keller

1994-07-01T23:59:59.000Z

432

Black holes, information, and Hilbert space for quantum gravity  

E-Print Network (OSTI)

A coarse-grained description for the formation and evaporation of a black hole is given within the framework of a unitary theory of quantum gravity preserving locality, without dropping the information that manifests as ...

Nomura, Yasunori

433

Mixed Rossby–Gravity Waves Triggered by Lateral Forcing  

Science Conference Proceedings (OSTI)

The mechanisms associated with the excitation of mixed Rossby-gravity waves (MRGWs) in the upper troposphere are studied using wind and outgoing longwave radiation (OLR) data from 1979 to 1991. The largest anomalies in meridional wind associated ...

Victor Magaña; Michio Yanai

1995-05-01T23:59:59.000Z

434

Mutual Intrusion of a Gravity Current and Density Front Formation  

Science Conference Proceedings (OSTI)

A two-dimensional prognostic model was employed to examine the mutual intrusion of a gravity current and the formation of a density front. The results indicated strong vertical motion near the front and, with Earth rotation included, a baroclinic ...

Dono-Ping Wang

1984-07-01T23:59:59.000Z

435

Gravity Waves and Convection in Colorado during July 1983  

Science Conference Proceedings (OSTI)

In order to gain insight into the complex dynamics of a convective system interacting with a gravity wave train, we have carried out an experiment in northeast Colorado during July and August, 1983, utilizing data from several program areas in ...

F. Einaudi; W. L. Clark; J. L. Green; T. E. VanZandt; D. Fua

1987-06-01T23:59:59.000Z

436

Status of Matter-Gravity Couplings in the SME  

E-Print Network (OSTI)

Constraints on Lorentz violation in matter-gravity couplings are summarized along with existing proposals to obtain sensitivities that exceed current limits by up to 11 orders of magnitude.

Tasson, Jay D

2013-01-01T23:59:59.000Z

437

Dynamic Excitation of Internal Gravity Waves in the Equatorial Oceans  

Science Conference Proceedings (OSTI)

It is proposed that shear instability of the upper flank of the equatorial undercurrent may generate, under a broad range of conditions, downward propagating internal gravity waves (IGW) of large amplitude. The generation mechanism is shown to ...

B. R. Sutherland

1996-11-01T23:59:59.000Z

438

A Forced Gravity Wave Model of Serf-Organizing Convection  

Science Conference Proceedings (OSTI)

A two-dimensional, hydrostatic, nonrotating numerical model with a cumulus paramelerizafion is developed to study the early stages of mesozcale convective systems. Amplifying, forced gravity waves occur when peneirative downdrafts are present. ...

David J. Raymond

1987-12-01T23:59:59.000Z

439

A Theory of Gravity Wave Absorption by a Boundary Layer  

Science Conference Proceedings (OSTI)

A one-layer model of the atmospheric boundary layer (BL) is proposed to explain the nature of lee-wave attenuation and gravity wave absorption seen in numerical simulations. Two complex coefficients are defined: the compliance coefficient and the ...

Ronald B. Smith; Qingfang Jiang; James D. Doyle

2006-02-01T23:59:59.000Z

440

Instantons in the Quantum Framework of 2D Gravity  

E-Print Network (OSTI)

We analyze the non--perturbative features of 2D quantum gravity defined by stochastic regularization of the unstable matrix model showing, first, that the WKB approximation of the well-defined quantum Fokker-Planck hamiltonian corresponds to the semiclassical eigenvalue density of the former. The double scaled potential exhibits an instanton--like behaviour, which is universal and scales, but whose interpretation in terms of pure gravity is still open.

J. Luis Miramontes; Joaquin Sanchez Guillen

1991-10-18T23:59:59.000Z

Note: This page contains sample records for the topic "gravity astm american" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Two-phase computer codes for zero-gravity applications  

SciTech Connect

This paper discusses the problems existing in the development of computer codes which can analyze the thermal-hydraulic behavior of two-phase fluids especially in low gravity nuclear reactors. The important phenomenon affecting fluid flow and heat transfer in reduced gravity is discussed. The applicability of using existing computer codes for space applications is assessed. Recommendations regarding the use of existing earth based fluid flow and heat transfer correlations are made and deficiencies in these correlations are identified.

Krotiuk, W.J.

1986-10-01T23:59:59.000Z

442

Dark Matter and Dark Energy as Effects of Quantum Gravity  

E-Print Network (OSTI)

I present a theory of quantum gravity based on the principle of gravitational energy fluctuations. Gravitational energy fluctuations -- gravitons -- are responsible for elastic scattering of subatomic particles. Such scattering corresponds to complimentary force -- graviton scattering force -- arising in gravitational interaction in addition to Newtonian gravity. The strength of the graviton scattering force is proportional to the graviton scattering probability. Unlike Newtonian gravity the graviton scattering force follows the 1/r law and dominates the former on cosmological scale in the limit of low orbital accelerations. Similarly to Modified Newtonian Dynamics the quantum gravity accounts for variations in observed M/L ratios of diverse stellar systems ranging from dwarf spheroid galaxies to X-ray galaxy clusters without requiring an invisible matter (which is still required by MOND in X-Ray cluster cores). Unlike MOND the presented theory neither violates cornerstone Newton Laws nor suffers from the ambiguity of acceleration frames while enjoying vast experimental evidence usually cited in favor of MOND. To ascertain the validity of the presented theory I have examined the predictions of quantum gravity for dwarf spheroid, ordinary and giant elliptic galaxies, and X-ray clusters. In all cases quantum gravity yields M/L ratios and scaling relations consistent with observations. Quantum gravity accounts for the tilt of the Fundamental Plane of elliptical galaxies erasing the differences in M/L vs. luminosity relations for faint and bright ellipticals, which cannot be easily explained by CDM model. Lastly, by analyzing the behavior of the gravitational energy fluctuations in the limit of high matter density expected in the early Universe I show that primordial inflation and dark energy (i.e. non-zero cosmological constant) arise as natural effects of quantum gravity in the expanding Universe.

Max I. Fomitchev

2010-09-07T23:59:59.000Z

443

Dark Energy, Induced Gravity and Broken Scale Invariance  

E-Print Network (OSTI)

We study the cosmological evolution of an induced gravity model with a self-interacting scalar field $\\sigma$ and in the presence of matter and radiation. Such model leads to Einstein Gravity plus a cosmological constant as a stable attractor among homogeneous cosmologies and is therefore a viable dark-energy (DE) model for a wide range of scalar field initial conditions and values for its positive $\\gamma$ coupling to the Ricci curvature $\\gamma \\sigma^{2}R$.

Finelli, F; Venturi, G

2008-01-01T23:59:59.000Z

444

Gravity assisted dark energy dominance and cosmic acceleration  

E-Print Network (OSTI)

It is proposed that dark energy may become dominant over standard matter due to universe expansion (curvature decrease). Two models: non-linear gravity-matter system and modified gravity may provide the effective phantom or effective quintessence dark energy which complies with the conjecture. It is interesting that future of such universe is not necessary finite time singularity (Big Rip). The effective quintessence naturally describes current cosmic speed-up.

Nojiri, S; Nojiri, Shin'ichi; Odintsov, Sergei D.

2004-01-01T23:59:59.000Z

445

Solar system constraints on R$^n$ gravity  

E-Print Network (OSTI)

Recently, gravitational microlensing has been investigated in the framework of the weak field limit of fourth order gravity theory. However, solar system data (i.e. planetary periods and light bending) can be used to put strong constraints on the parameters of this class of gravity theories. We find that these parameters must be very close to those corresponding to the Newtonian limit of the theory.

A. F. Zakharov; A. A. Nucita; F. De Paolis; G. Ingrosso

2006-11-02T23:59:59.000Z

446

Gravity-free hydraulic jumps and metal femtocups  

E-Print Network (OSTI)

Hydraulic jumps created by gravity are seen every day in the kitchen sink. We show that at small scales a circular hydraulic jump can be created in the absence of gravity, by surface tension. The theory is motivated by our experimental finding of a height discontinuity in spreading submicron molten metal droplets created by pulsed-laser ablation. By careful control of initial conditions, we show that this leads to solid femtolitre cups of gold, silver, copper, niobium and tin.

Rama Govindarajan; Manikandan Mathur; Ratul DasGupta; N. R. Selvi; Neena Susan John; G. U. Kulkarni

2006-10-03T23:59:59.000Z

447

Evaporation Time of Ho?ava Gravity Black Holes  

Science Conference Proceedings (OSTI)

Recently it has been a lot of interest in the theory proposed by Ho?ava because is a remormalizable theory of gravity and may be a candidate for the UV completion of Einstein gravity. In the present work we study thermodynamical properties of black hole type solutions in this setup. In particular we are able to obtain times of evaporation for black hole solution in this formalism.

S. Pérez?Payán; M. Sabido

2011-01-01T23:59:59.000Z

448

Centrifuge Modeling and Analysis of Concrete Gravity Dams  

Science Conference Proceedings (OSTI)

This report contains general background information on centrifuge experimentation and linear elastic fracture mechanics pertaining to concrete gravity dam models, and explains in detail the experimental methodology and procedures developed for testing concrete gravity dam models in centrifuges. An important detail in the experimental procedure is that the models are loaded upstream with water and, at fracture, have water uplift pressure within any cracks. Finally, test results and comparisons to analytic...

1995-12-14T23:59:59.000Z

449

Revised spherically symmetric solutions of $R+\\varepsilon/R$ gravity  

E-Print Network (OSTI)

We study spherically symmetric static empty space solutions in $R+\\varepsilon/R$ model of $f(R)$ gravity. We show that the Schwarzschild metric is an exact solution of the resulted field equations and consequently there are general solutions which {are perturbed Schwarzschild metric and viable for solar system. Our results for large scale contains a logarithmic term with a coefficient producing a repulsive gravity force which is in agreement with the positive acceleration of the universe.

Kh. Saaidi; S. W. Rabiei; A. Aghamohammadi

2011-12-31T23:59:59.000Z

450

Universality of second order transport in Gauss-Bonnet gravity  

E-Print Network (OSTI)

We compute all the second order transport coefficients of a hydrodynamic theory with a gravity dual which includes a Gauss-Bonnet term. We find that a particular linear combination of the second order transport coefficients, which was found to vanish in generic two derivative gravity theories with matter, remains zero even in the presence of the Gauss-Bonnet term. We contrast this behavior with the shear viscosity to entropy density ratio.

Evgeny Shaverin; Amos Yarom

2012-11-08T23:59:59.000Z

451

AMERICAN STATISTICAL ASSOCIATION  

U.S. Energy Information Administration (EIA) Indexed Site

AMERICAN STATISTICAL ASSOCIATION AMERICAN STATISTICAL ASSOCIATION + + + + + COMMITTEE ON ENERGY STATISTICS + + + + + FALL MEETING + + + + + FRIDAY OCTOBER 17, 2003 + + + + + The Committee met in Room 8E089 in the Forrestal Building, 1000 Independence Avenue, S.W., Washington, D.C., at 8:30 a.m., Jay Breidt, Chair, presiding. PRESENT F. JAY BREIDT Chair NICOLAS HENGARTNER Vice Chair JOHNNY BLAIR Committee Member MARK BURTON Committee Member JAE EDMONDS Committee Member MOSHE FEDER Committee Member JAMES K. HAMMITT Committee Member NEHA KHANA Committee Member NAGARAJ K. NEERCHAL Committee Member

452

AMERICAN STATISTICAL ASSOCIATION (ASA)  

U.S. Energy Information Administration (EIA) Indexed Site

AMERICAN STATISTICAL ASSOCIATION (ASA) AMERICAN STATISTICAL ASSOCIATION (ASA) MEETING OF THE COMMITTEE ON ENERGY STATISTICS WITH THE ENERGY INFORMATION ADMINISTRATION (EIA) Washington, D.C. Friday, April 29, 2005 COMMITTEE MEMBERS: NICOLAS HENGARTNER, Chair Los Alamos National Laboratory MARK BERNSTEIN RAND Corporation CUTLER CLEVELAND Center for Energy and Environmental Studies JAE EDMONDS Pacific Northwest National Laboratory MOSHE FEDER Research Triangle Institute BARBARA FORSYTH Westat WALTER HILL St. Mary's College of Maryland NEHA KHANNA Binghamton University NAGARAJ K. NEERCHAL University of Maryland Baltimore County SUSAN M. SEREIKA University of Pittsburgh DARIUS SINGPURWALLA LECG RANDY R. SITTER Simon Fraser University ALSO PRESENT: MARGOT ANDERSON Energy Information Administration ALSO PRESENT (CONT'D):

453

TESTING ALTERNATIVE THEORIES OF GRAVITY USING THE SUN  

SciTech Connect

We propose a new approach to test possible corrections to Newtonian gravity using solar physics. The high accuracy of current solar models and new precise observations allow us to constrain corrections to standard gravity at unprecedented levels. Our case study is Eddington-inspired gravity, an attractive modified theory of gravity which results in non-singular cosmology and collapse. The theory is equivalent to standard gravity in vacuum, but it sensibly differs from it within matter. For instance, it affects the evolution and the equilibrium structure of the Sun, giving different core temperature profiles, and deviations in the observed acoustic modes and in solar neutrino fluxes. Comparing the predictions from a modified solar model with observations, we constrain the coupling parameter of the theory, |{kappa}{sub g}| {approx}< 3 Multiplication-Sign 10{sup 5} m{sup 5} s{sup -2} kg{sup -1}. Our results show that the Sun can be used to efficiently constrain alternative theories of gravity.

Casanellas, Jordi; Pani, Paolo; Lopes, Ilidio; Cardoso, Vitor, E-mail: jordicasanellas@ist.utl.pt, E-mail: paolo.pani@ist.utl.pt, E-mail: ilidio.lopes@ist.utl.pt, E-mail: vitor.cardoso@ist.utl.pt [CENTRA, Departamento de Fisica, Instituto Superior Tecnico, Universidade Tecnica de Lisboa-UTL, Av. Rovisco Pais 1, 1049 Lisboa (Portugal)

2012-01-20T23:59:59.000Z

454

Dynamical horizon entropy and equilibrium thermodynamics of generalized gravity theories  

Science Conference Proceedings (OSTI)

We study the relation between the thermodynamics and field equations of generalized gravity theories on the dynamical trapping horizon with sphere symmetry. We assume the entropy of a dynamical horizon as the Noether charge associated with the Kodama vector and point out that it satisfies the second law when a Gibbs equation holds. We generalize two kinds of Gibbs equations to Gauss-Bonnet gravity on any trapping horizon. Based on the quasilocal gravitational energy found recently for f(R) gravity and scalar-tensor gravity in some special cases, we also build up the Gibbs equations, where the nonequilibrium entropy production, which is usually invoked to balance the energy conservation, is just absorbed into the modified Wald entropy in the Friedmann-Robertson-Walker spacetime with slowly varying horizon. Moreover, the equilibrium thermodynamic identity remains valid for f(R) gravity in a static spacetime. Our work provides an alternative treatment to reinterpret the nonequilibrium correction and supports the idea that the horizon thermodynamics is universal for generalized gravity theories.

Wu Shaofeng; Ge Xianhui; Yang Guohong [Department of Physics, Shanghai University, Shanghai, 200444 (China); Shanghai Key Lab of Astrophysics, Shanghai, 200234 (China); Zhang Pengming [Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000 (China); Institute of Modern Physics, Lanzhou, 730000 (China)

2010-02-15T23:59:59.000Z

455

Minimal Liouville Gravity correlation numbers from Douglas string equation  

E-Print Network (OSTI)

We continue the study of $(q,p)$ Minimal Liouville Gravity with the help of Douglas string equation. We generalize the results of \\cite{Moore:1991ir}, \\cite{Belavin:2008kv}, where Lee-Yang series $(2,2s+1)$ was studied, to $(3,3s+p_0)$ Minimal Liouville Gravity, where $p_0=1,2$. We demonstrate that there exist such coordinates $\\tau_{m,n}$ on the space of the perturbed Minimal Liouville Gravity theories, in which the partition function of the theory is determined by the Douglas string equation. The coordinates $\\tau_{m,n}$ are related in a non-linear fashion to the natural coupling constants $\\lambda_{m,n}$ of the perturbations of Minimal Lioville Gravity by the physical operators $O_{m,n}$. We find this relation from the requirement that the correlation numbers in Minimal Liouville Gravity must satisfy the conformal and fusion selection rules. After fixing this relation we compute three- and four-point correlation numbers when they are not zero. The results are in agreement with the direct calculations in Minimal Liouville Gravity available in the literature \\cite{Goulian:1990qr}, \\cite{Zamolodchikov:2005sj}, \\cite{Belavin:2006ex}.

Alexander Belavin; Boris Dubrovin; Baur Mukhametzhanov

2013-10-21T23:59:59.000Z

456

Black hole phase transitions in Horava-Lifshitz gravity  

SciTech Connect

We study black hole phase transitions in (deformed) Horava-Lifshitz (H-L) gravity, including the charged/uncharged topological black holes and KS black hole. Stability analysis and state space geometry are both used. We find interesting phase structures in these black holes, some of the properties are never observed in Einstein gravity. Particularly, the stability properties of black holes in H-L gravity with small radius change dramatically, which can be considered as a leak of information about the small scale behavior of spacetime. A new black hole local phase transition in H-L gravity which cannot be revealed by thermodynamical metrics has been found. There is an infinite discontinuity at the specific heat curve for charged black hole in H-L gravity with hyperbolic event horizon. However, this discontinuity does not have a corresponding curvature singularity of thermodynamical metrics. Our results may provide new insights towards a better understanding of the H-L gravity, as well as black hole thermodynamics.

Cao Qiaojun; Chen Yixin; Shao Kainan [Zhejiang Institute of Modern Physics, Zhejiang University, Hangzhou, 310027 (China)

2011-03-15T23:59:59.000Z

457

Solar System Tests of f(R) Gravity  

E-Print Network (OSTI)

In this paper, we study the solar system tests of f(R) gravity. When the field f' is light, the post-Newtonian parameter gamma is equal to 1/2. We reobtain this result by focusing on the equations of motion for f(R) gravity in the Jordan frame. The result of gamma=1/2 is a gross violation of the observational value gamma=1. The chameleon mechanism in the Jordan frame is implemented in order to make f(R) gravity pass the solar system tests. The problem of the solar system tests of f(R) gravity is almost identical to the scenario of the false vacuum decay. Consequently, the condition for the validity of a thin-wall approximation in the false vacuum decay can be used as the new condition for the solar system tests. This new condition provides a pictorial interpretation to the solar system tests of f(R) gravity. Numerical simulations of the solar system tests of f(R) gravity are implemented. The combination of analytic and numerical approaches enables us to ascertain whether an f(R) model can pass the solar syste...

Guo, Jun-Qi

2013-01-01T23:59:59.000Z

458

Gravity Waves in a Horizontal Shear Flow. Part II: Interaction between Gravity Waves and Potential Vorticity Perturbations  

Science Conference Proceedings (OSTI)

Interaction among potential vorticity perturbations and propagating internal gravity waves in a horizontally sheared zonal flow is investigated. In the strong stratification limit, an initial vorticity perturbation weakly excites two propagating ...

Nikolaos A. Bakas; Brian F. Farrell

2009-03-01T23:59:59.000Z

459

Doppler Sodar and Radar Wind-Profiler Observations Of Gravity-Wave Activity Associated with a Gravity Current  

Science Conference Proceedings (OSTI)

Observations from two Doppler sodars and a radar wind profiler have been used in conjunction with data from a rawinsonde station and a mesoscale surface observation network to conduct a case study of a gravity current entering into an environment ...

F. M. Ralph; C. Mazaudier; M. Crochet; S. V. Venkateswaran

1993-02-01T23:59:59.000Z

460

Testing gravity law in the solar system  

E-Print Network (OSTI)

The predictions of General relativity (GR) are in good agreement with observations in the solar system. Nevertheless, unexpected anomalies appeared during the last decades, along with the increasing precision of measurements. Those anomalies are present in spacecraft tracking data (Pioneer and flyby anomalies) as well as ephemerides. In addition, the whole theory is challenged at galactic and cosmic scales with the dark matter and dark energy issues. Finally, the unification in the framework of quantum field theories remains an open question, whose solution will certainly lead to modifications of the theory, even at large distances. As long as those "dark sides" of the universe have no universally accepted interpretation nor are they observed through other means than the gravitational anomalies they have been designed to cure, these anomalies may as well be interpreted as deviations from GR. In this context, there is a strong motivation for improved and more systematic tests of GR inside the solar system, with the aim to bridge the gap between gravity experiments in the solar system and observations at much larger scales. We review a family of metric extensions of GR which preserve the equivalence principle but modify the coupling between energy and curvature and provide a phenomenological framework which generalizes the PPN framework and "fifth force" extensions of GR. We briefly discuss some possible observational consequences in connection with highly accurate ephemerides.

B. Lamine; J. -M. Courty; S. Reynaud; M. -T. Jaekel

2011-05-31T23:59:59.000Z

Note: This page contains sample records for the topic "gravity astm american" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Introduction to Quantum-Gravity Phenomenology  

E-Print Network (OSTI)

After a brief review of the first phase of development of Quantum-Gravity Phenomenology, I argue that this research line is now ready to enter a more advanced phase: while at first it was legitimate to resort to heuristic order-of-magnitude estimates, which were sufficient to establish that sensitivity to Planck-scale effects can be achieved, we should now rely on detailed analyses of some reference test theories. I illustrate this point in the specific example of studies of Planck-scale modifications of the energy/momentum dispersion relation, for which I consider two test theories. Both the photon-stability analyses and the Crab-nebula synchrotron-radiation analyses, which had raised high hopes of ``beyond-Plankian'' experimental bounds, turn out to be rather ineffective in constraining the two test theories. Examples of analyses which can provide constraints of rather wide applicability are the so-called ``time-of-flight analyses'', in the context of observations of gamma-ray bursts, and the analyses of the cosmic-ray spectrum near the GZK scale.

Giovanni Amelino-Camelia

2004-12-30T23:59:59.000Z

462

Diversity of universes created by pure gravity  

E-Print Network (OSTI)

We show that a number of problems of modern cosmology may be solved in the framework of multidimensional gravity with high-order curvature invariants, without invoking other fields. We use a method employing a slow-change approximation, able to work with rather a general form of the gravitational action, and consider Kaluza-Klein type space-times with one or several extra factor spaces. A vast choice of effective theories suggested by the present framework may be stressed: even if the initial Lagrangian is entirely fixed, one obtains quite different models for different numbers, dimensions and topologies of the extra factor spaces. As examples of problems addressed we consider (i) explanation of the present accelerated expansion of the Universe, with a reasonably small cosmological constant, and the problem of its fine tuning is considered from a new point of view; (ii) the mechanism of closed wall production in the early Universe; such walls are necessary for massive primordial black hole formation which is an important stage in some scenarios of cosmic structure formation; (iii) sufficient particle production rate at the end of inflation; (iv) it is shown that our Universe may contain spatial domains with a macroscopic size of extra dimensions. We also discuss chaotic attractors appearing at possible nodes of the kinetic term of the effective scalar field Lagrangian.

K. A. Bronnikov; R. V. Konoplich; S. G. Rubin

2006-10-01T23:59:59.000Z

463

Momentum and Energy Transport by Gravity Waves in Stochastically Driven Stratified Flows. Part II: Radiation of Gravity Waves from a Gaussian Jet  

E-Print Network (OSTI)

Momentum and Energy Transport by Gravity Waves in Stochastically Driven Stratified Flows. Part II: Radiation of Gravity Waves from a Gaussian Jet NIKOLAOS A. BAKAS AND BRIAN F. FARRELL Harvard University Interaction between the midlatitude jet and gravity waves is examined, focusing on the nonnormality

Farrell, Brian F.

464

The First Americans  

NLE Websites -- All DOE Office Websites (Extended Search)

Americans Americans Nature Bulletin No. 360-A November 29, 1969 Forest Preserve District of Cook County George W. Dunne, President Roland F. Eisenbeis, Supt. of Conservation THE FIRST AMERICANS When the Norsemen and then Columbus "discovered" America they found people here -- people with bronze skins and straight black hair. Because he thought he had sailed across the world and found a sea passage to India. Columbus called these people "Indios". He was wrong but we still call them Indians. It is now generally accepted by scientists that the first humans arrived on this American continent some thirty or forty thousand years ago. It is believed that they came from Asia, across what we call Bering Strait. The distance from the islands at the westernmost tip of Alaska to the easternmost tip of Siberia is only 59 miles. In clear weather you can see from land to land. In ancient times there may have been a bridge of solid ice between the two shores, or there might have been an actual land connection between the two continents. But even if there were a 5-mile gap of water it could have been crossed in primitive canoes by hungry people hunting for game. Hunger has been the mainspring of civilization.

465

Latin American Section List  

Science Conference Proceedings (OSTI)

Name AffiliationCity, State, CountryLatin American Section2013 Members208 Members as of October 1, 2013Abril, RubenDSM Nutritional ProductsBoulder, CO, USAAcevedo, NuriaUniversity of GuelphAmes, IA, USAAcosta, EdgarUniversity of TorontoToronto, ON, CanadaA

466

Infiltration in ASHRAE's Residential Ventilation Standards  

E-Print Network (OSTI)

Engineers, Atlanta, GA.  (1993)  ASTM, Standard E1827?96, “Standard Test Methods for Determining Airtightness of Door”,  ASTM  Book  of  Standards,  American  Society  of 

Sherman, Max

2008-01-01T23:59:59.000Z

467

A gravity model for the Coso geothermal area, California | Open Energy  

Open Energy Info (EERE)

gravity model for the Coso geothermal area, California gravity model for the Coso geothermal area, California Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Proceedings: A gravity model for the Coso geothermal area, California Details Activities (1) Areas (1) Regions (0) Abstract: Two- and three-dimensional gravity modeling was done using gridded Bouguer gravity data covering a 45 x 45 km region over the Coso geothermal area in an effort to identify features related to the heat source and to seek possible evidence for an underlying magma chamber. Isostatic and terrain corrected Bouguer gravity data for about 1300 gravity stations were obtained from the US Geological Survey. After the data were checked, the gravity values were gridded at 1 km centers for the area of interest centered on the Coso volcanic field. Most of the gravity

468

Gravity survey of the southwestern part of the sourthern Utah geothermal belt  

DOE Green Energy (OSTI)

A gravity survey covering an area of 6200 km/sup 2/ was made over the southwestern part of the southern Utah geothermal belt. The objective of the gravity survey is to delineate the geologic structures and assist in the understanding of the geothermal potential of the area. A total of 726 new gravity stations together with 205 existing gravity stations, are reduced to give: (1) a complete Bouguer gravity anomaly map, and (2) a fourth-order residual gravity anomaly map; both maps have a 2-mgal contour interval. The complete Bouguer gravity anomaly map shows an east-trending regional gravity belt with a total relief of about 70 mgal which crosses the central portion of the survey area. The gravity belt is attributed to a crustal lateral density variation of 0.1 gm/cc from a depth of 5 to 15 km.

Green, R.T.; Cook, K.L.

1981-03-01T23:59:59.000Z

469

A gravity model for the Coso geothermal area, California  

DOE Green Energy (OSTI)

Two- and three-dimensional gravity modeling was done using gridded Bouguer gravity data covering a 45 {times} 45 km region over the Coso geothermal area in an effort to identify features related to the heat source and to seek possible evidence for an underlying magma chamber. Isostatic and terrain corrected Bouguer gravity data for about 1300 gravity stations were obtained from the US Geological Survey. After the data were checked, the gravity values were gridded at 1 km centers for the area of interest centered on the Coso volcanic field. Most of the gravity variations can be explained by two lithologic units: (1) low density wedges of Quarternary alluvium with interbedded thin basalts (2.4 g/cm{sup 3}) filling the Rose Valley and Coso Basin/Indian Wells Valley, and (2) low density cover of Tertiary volcanic rocks and intercalated Coso Formation (2.49 g/cm{sup 3}). A 3-D iterative approach was used to find the thicknesses of both units. The gravity anomaly remaining after effects from Units 1 and 2 are removed is a broad north-south-trending low whose major peak lies 5 km north of Sugarloaf Mountain, the largest of the less than 0.3 m.y. old rhyolite domes in the Coso Range. Most of this residual anomaly can be accounted for by a deep, low-density (2.47 g/cm{sup 3}) prismatic body extending from 8 to about 30 km below the surface. While some of this anomaly might be associated with fractured Sierran granitic rocks, its close correlation to a low-velocity zone with comparable geometry suggests that the residual anomaly is probably caused a large zone of partial melt underlying the rhyolite domes of the Coso Range. 12 refs., 9 figs.

Feighner, M.A.; Goldstein, N.E.

1990-08-01T23:59:59.000Z

470

Inflation by purely kinetic coupled gravity  

E-Print Network (OSTI)

We study a purely kinetic coupled scalar-tensor gravity. We use FRW metric and obtain the modified Friedmann equations subject to an effective perfect fluid including energy density $\\rho_{\\phi}=\\rho_{g}+\\rho_{_G}$ and pressure $p_{\\phi}=p_{g}+p_{_G}$, where $(\\rho_{g}, p_{g})$ and $(\\rho_{_G}, p_{_G})$ define the perfect fluids corresponding to the coupling of scalar field dynamics with metric and Einstein tensors, respectively. We find that the inflation can occur in this model provided that $p_{_G}=-\\rho_{_G}$. We define Hubble slow-role parameters and find that the Hubble slow-role regime means $\\rho_{_{g}}\\ll\\rho_{_{G}}$. It turns out that the energy is not conserved for the scalar field and its kinetic energy is growing exponentially during inflation. It is proposed that this energy may be supplied by the quantum fluctuations of vacuum. This rapid transfer of energy density from vacuum to the scalar field may solve the cosmological constant problem. When $\\rho_{_{g}}$ becomes sufficiently large, the Hubble parameter starts decreasing and $\\rho_{_{g}}$ becomes comparable with $\\rho_{_{G}}$, hence the slow-role approximation is violated, and the inflation is ended. The large energy density of the scalar field may be transformed, partly into the matter, and partly into the radiation, and the universe experiences a reheating phase. At late times, the kinetic energy of the scalar field decreases as $a^{-6}$ and the remnant energy density of the scalar field may become a source of dark matter. Also, we study the cosmological perturbations during the inflation and obtain the behaviors of perturbations inside and outside the horizon. These results are in agreement with those obtained in common inflationary scenarios.

F. Darabi; A. Parsiya

2013-12-04T23:59:59.000Z

471

American Municipal Power (Public Electric Utilities) - Residential...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

American Municipal Power (Public Electric Utilities) - Residential Efficiency Smart Program (Ohio) American Municipal Power (Public Electric Utilities) - Residential Efficiency...

472

Correlation between precision gravity and subsidence measurements at Cerro Prieto  

DOE Green Energy (OSTI)

Precision gravity measurements were made in the region of the Cerro Prieto geothermal field at yearly intervals from 1977 to 1981 to assess the feasibility of using gravity to determine subsurface reservoir changes with time. The extent of mass recharge in response to the continued production of fluids from this field was studied. Changes in gravity and ground elevation were observed throughout the region for the period of observation. Results indicate that the largest changes observed were the result of the Magnitude 6.1 (Caltech) Victoria earthquake of 8 June 1980. The epicenter of this earthquake was located 25 km southeast of the field on the Cerro Prieto Fault, which bounds the field on the southwest. Subsidence of up to 55 cm was measured east of the power plant, in the region between the northern end of the Cerro Prieto Fault and the southern end of the Imperial Fault. This area has been postulated to be the site of an active spreading center or pull-apart basin, and has been characterized by a high level of seismic activity during the last 10 years. Minor subsidence and small related gravity changes for the period preceeding the Victoria earthquake suggest that in spite of large fluid production rates, the reservoir is being almost completely recharged and that a measurable increase in subsurface density may be taking place. The results of measurements of horizontal ground motions made in this area are discussed in relation to the gravity and subsidence observations.

Zelwer, R.; Grannell, R.B.

1982-10-01T23:59:59.000Z

473

Waste Isolation Pilot Plant (WIPP) site gravity survey and interpretation  

Science Conference Proceedings (OSTI)

A portion of the WIPP site has been extensively surveyed with high-precision gravity. The main survey (in T22S, R31E) covered a rectangular area 2 by 4-1/3 mi encompassing all of WIPP site Zone II and part of the disturbed zone to the north of the site. Stations were at 293-ft intervals along 13 north-south lines 880 ft apart. The data are considered accurate to within a few hundredths of a milligal. Long-wavelength gravity anomalies correlate well with seismic time structures on horizons below the Castile Formation. Both the gravity anomalies and the seismic time structures are interpreted as resulting from related density and velocity variations within the Ochoan Series. Shorter wavelength negative gravity anomalies are interpreted as resulting from bulk density alteration in the vicinity of karst conduits. The WIPP gravity survey was unable to resolve low-amplitude, long-wavelength anomalies that should result from the geologic structures within the disturbed zone. It did indicate the degree and character of karst development within the surveyed area.

Barrows, L.J.; Fett, J.D.

1983-04-01T23:59:59.000Z

474

NORTH AMERICAN WATER OFFICE  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

NORTH AMERICAN WATER OFFICE NORTH AMERICAN WATER OFFICE P.O. Box 174 Lake Elmo, MN 55042 Phone: (612) 770-3861 Fax: (612) 770-3976 January 30, 1998 US Department of Energy Office of General Council GC-52 1000 Independence Ave. SW Washington DC 20585 RE: Preparation of Report to Congress on Price-Anderson Act Dear Office of General Council: The Price Anderson Act should be eliminated. The Price Anderson Act assumes that the encouragement and growth of the commercial nuclear industry is in the public interest. It is not. Rational evaluation of the commercial nuclear industry forces the conclusion that the Price Anderson Act simply shields the commercial nuclear industry from costs that it would otherwise, in a fair market setting, be forced to internalize and pay. Price Anderson amounts to

475

AMERICAN HERITAGE OF  

NLE Websites -- All DOE Office Websites (Extended Search)

AMERICAN HERITAGE OF AMERICAN HERITAGE OF raven 10~ SUMMER 1995 $d.OU VOLUME 11/NU~IBH;R 1 i Y .rt: r "~ ~:rih a ~~ to Invent * Tf~e~'' ~ °of _._.. , _._~.__ ~y~,: ..~_, ec no o~ r HE TOM OMB FIFTY YEARS AGO THIS SUNI~fER, THE WORLD WAS changed forever when the first nuclear bomb ex- ploded above the New Mexico desert and then bombs were dropped on the cities of Hiroshima and Nagasaki, Japan. The moral, psychological, and geopolitical ramifications of this most powerful and revolution- ary of all technologies and its use have been matters of universal con- cern ever since. They will undoubtedly be the subject of particularly intense discussion this summer. Invention ~ Technology's contribution is a look at the anniversary from the magazine's unique perspective, examining the making of the

476

The American Elm  

NLE Websites -- All DOE Office Websites (Extended Search)

Elm Elm Nature Bulletin No. 279-A October 21, 1967 Forest Preserve District of Cook County Richard B. Ogilvie, President Roland F. Eisenbeis, Supt. of Conservation THE AMERICAN ELM For three centuries, the stately graceful American Elm -- "the tree that like a fountain rises" -- has been our favorite shade tree, and around it have grown some of our finest traditions. The early colonists found huge patriarchs, which reminded them of the magnificent English Elms, and they planted seedlings to shade their homes and village commons. Today, innumerable New England roadways are lined with giant elms, their great arching limbs forming canopies like a cathedral roof. When the pioneers moved westward, they found this tree everywhere in the bottomlands and on low fertile hills. NOW, throughout the Middle West -- even in prosaic prairie towns -- streets and public buildings are shaded and given character by beautiful elms.

477

-APTKA E AMERICAN O  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

APTKA E AMERICAN O APTKA E AMERICAN O w ~%~'~ PUBCIC TRANSPORTATION fa ASSOCIATION 2001-006487 3/9 P 4:06 Wash March 7, 2001 Eal , The Honorable Spencer Abraham al Secretary iodadbpOa U.S. Department of Energy wr dL b, Forrestal Building 6dJS 1 * 1000 Independence Avenue, N.W. BaA roB Washington, DC 20585-1000 GWE KtsO mg Dear Mr. Secretary: hidcI ABd ramnU I Ssb 6idL fian I write on behalf of the American Public Transportation Association (APTA) to SWais express support for the development of a national energy policy. As President Bush Ei;. LtrW highlighted in his February 27 address to a joint session of Congress, regional energy e, &mw^, u* shortages have become serious concerns and have brought attention to this major issue GhaI facing our country. iBtdL Wd _r.nwabtis As the trade association representing the public transportation industry, we would

478

Ground Gravity Survey At Truckhaven Area (Layman Energy Associates, 2009) |  

Open Energy Info (EERE)

Truckhaven Area (Layman Energy Associates, 2009) Truckhaven Area (Layman Energy Associates, 2009) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Ground Gravity Survey At Truckhaven Area (Layman Energy Associates, 2009) Exploration Activity Details Location Truckhaven Area Exploration Technique Ground Gravity Survey Activity Date Usefulness useful DOE-funding Unknown Notes The area of coverage for the DOE-funded geophysical surveys is shown in Figure 9. The 95 magnetotelluric (MT) soundings cover a central area of about 80 square kilometers. The 126 gravity stations extend over a broader area of about 150 square kilometers, centered on the same area covered by the MT soundings. A detailed description of the instrumentation and data acquisition procedures used for both surveys is provided in GSY-USA, Inc.

479

Nonlinear Gravity Theories in the Metric and Palatini Formalisms  

E-Print Network (OSTI)

We study nonlinear gravity theories in both the metric and the Palatini (metric-affine) formalisms. The nonlinear character of the gravity lagrangian in the metric formalism causes the appearance of a scalar source of matter in Einstein’s equations that can be interpreted as a quintessence field. However, in the Palatini case no new energy sources appear, though the equations of motion get modified in such a way that usual matter can lead to repulsive gravity at very low densities. Thus, the Palatini formalism could provide a mechanism to explain the recent acceleration of the universe without the necessity of dark energy sources. We also show that in contrast to the metric formalism where only the Einstein frame should be considered as physical, the Palatini formalism allows both the Einstein and the Jordan frames to be physically acceptable.

Gonzalo J. Olmo A; William Komp A

2004-01-01T23:59:59.000Z

480

Nonlinear Gravity Theories in the Metric and Palatini Formalisms  

E-Print Network (OSTI)

We study nonlinear gravity theories in both the metric and the Palatini (metric-affine) formalisms. The nonlinear character of the gravity lagrangian in the metric formalism causes the appearance of a scalar source of matter in Einstein's equations that can be interpreted as a quintessence field. However, in the Palatini case no new energy sources appear, though the equations of motion get modified in such a way that usual matter can lead to repulsive gravity at very low densities. Thus, the Palatini formalism could provide a mechanism to explain the recent acceleration of the universe without the necessity of dark energy sources. We also show that in contrast to the metric formalism where only the Einstein frame should be considered as physical, the Palatini formalism allows both the Einstein and the Jordan frames to be physically acceptable.

Gonzalo J. Olmo; William Komp

2004-03-22T23:59:59.000Z

Note: This page contains sample records for the topic "gravity astm american" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


481

Will multiple probes of dark energy find modified gravity?  

SciTech Connect

One of the most pressing issues in cosmology is whether general relativity (GR) plus a dark sector is the underlying physical theory or whether a modified gravity model is needed. Upcoming dark energy experiments designed to probe dark energy with multiple methods can address this question by comparing the results of the different methods in constraining dark energy parameters. Disagreement would signal the breakdown of the assumed model (GR plus dark energy). We study the power of this consistency test by projecting constraints in the w{sub 0}-w{sub a} plane from the four different techniques of the Dark Energy Survey in the event that the underlying true model is modified gravity. We find that the standard technique of looking for overlap has some shortcomings, and we propose an alternative, more powerful Multidimensional Consistency Test. We introduce the methodology for projecting whether a given experiment will be able to use this test to distinguish a modified gravity model from GR.

Shapiro, Charles [Institute of Cosmology and Gravitation, Portsmouth, PO1 3FX (United Kingdom); Dodelson, Scott [Center for Particle Astrophysics, Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States); Department of Astronomy and Astrophysics, University of Chicago, Chicago, Illinois 60637 (United States); Kavli Institute for Cosmological Physics, Chicago, Illinois 60637 (United States); Hoyle, Ben [Institut de Ciencies del Cosmos, Barcelona (Spain); Samushia, Lado [Institute of Cosmology and Gravitation, Portsmouth, PO1 3FX (United Kingdom); National Abastumani Astrophysical Observatory, Ilia State University, 2A Kazbegi Ave, GE-0160 Tbilisi (Georgia); Flaugher, Brenna [Center for Particle Astrophysics, Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States)

2010-08-15T23:59:59.000Z

482

PROPAGATION OF GRAVITY WAVES IN A CONVECTIVE LAYER  

SciTech Connect

We perform numerical simulations of gravity mode propagation in a convective layer to investigate the observed association between small spatial scales and low frequencies in the photospheric velocity fields. According to the linear theory, when the fluid layer is convectively unstable, gravity modes are evanescent waves. However, in simple two-dimensional numerical settings, we find that when the equilibrium structure is modified by coherent large-scale convective motions, the waves injected at the bottom of the layer are no longer evanescent. In this situation, gravity waves can be detected at the surface of the layer. In our simplified model the injected wave's frequency remains unchanged, but its amplitude has a spatial modulation determined by the convective structure. This result may explain some analyses done with the proper orthogonal decomposition method of the solar surface velocity field even though solar convection is far more complex than the convection model considered here.

Onofri, M.; Vecchio, A.; Veltri, P. [Dipartimento di Fisica, Universita della Calabria, via P. Bucci, 87036 Rende (Italy); De Masi, G., E-mail: onofri@fis.unical.it [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, 35127 Padova (Italy)

2012-02-10T23:59:59.000Z

483

Gravity and subsurface investigation of the Presidio Bolson area, Texas  

DOE Green Energy (OSTI)

An integrated geophysical-geologic study of the Presidio Bolson area was undertaken primarily using gravity measurements and deep drilling data. Over 2000 gravity readings were used to construct maps of the area and two-dimensional computer modeling of gravity profiles was used to derive earth models. These data outlined the major geologic features of the area and were dominated by Tertiary block faulting and volcanism. The main feature of interest was the Presidio Bolson, which is located in a major graben (Presidio Graben) over 1 km deep in the area near Ruidosa, Texas. These data also suggest that hot springs associated with the Presidio Graben derive their heat from buried Tertiary intrusions associated with this graben or by deep circulation along the boundary faults of the graben.

Mraz, J.R.; Keller, G.R.

1977-01-01T23:59:59.000Z

484

Gravity Effects on Neutrino Masses in Split Supersymmetry  

E-Print Network (OSTI)

The mass differences and mixing angles of neutrinos can neither be explained by R-Parity violating split supersymmetry nor by flavor blind quantum gravity alone. It is shown that combining both effects leads, within the allowed parameter range, to good agreement with the experimental results. The atmospheric mass is generated by supersymmetry through mixing between neutrinos and neutralinos, while the solar mass is generated by gravity through flavor blind dimension five operators. Maximal atmospheric mixing forces the tangent squared of the solar angle to be equal to 1/2. The scale of the quantum gravity operator is predicted within a 5% error, implying that the reduced Planck scale should lie around the GUT scale. In this way, the model is very predictive and can be tested at future experiments.

Marco Aurelio Diaz; Benjamin Koch; Boris Panes

2009-02-10T23:59:59.000Z

485

Constraints on the quantum gravity scale from kappa - Minkowski spacetime  

E-Print Network (OSTI)

We compare two versions of deformed dispersion relations (energy vs momenta and momenta vs energy) and the corresponding time delay up to the second order accuracy in the quantum gravity scale (deformation parameter). A general framework describing modified dispersion relations and time delay with respect to different noncommutative kappa -Minkowski spacetime realizations is firstly proposed here and it covers all the cases introduced in the literature. It is shown that some of the realizations provide certain bounds on quadratic corrections, i.e. on quantum gravity scale, but it is not excluded in our framework that quantum gravity scale is the Planck scale. We also show how the coefficients in the dispersion relations can be obtained through a multiparameter fit of the gamma ray burst (GRB) data.

A. Borowiec; Kumar S. Gupta; S. Meljanac; A. Pachol

2009-12-17T23:59:59.000Z

486

Higgs-induced spectroscopic shifts near strong gravity sources  

SciTech Connect

We explore the consequences of the mass generation due to the Higgs field in strong gravity astrophysical environments. The vacuum expectation value of the Higgs field is predicted to depend on the curvature of spacetime, potentially giving rise to peculiar spectroscopic shifts, named hereafter 'Higgs shifts'. Higgs shifts could be searched through dedicated multiwavelength and multispecies surveys with high spatial and spectral resolution near strong gravity sources such as Sagittarius A* or broad searches for signals due to primordial black holes. The possible absence of Higgs shifts in these surveys should provide limits to the coupling between the Higgs particle and the curvature of spacetime, a topic of interest for a recently proposed Higgs-driven inflationary model. We discuss some conceptual issues regarding the coexistence between the Higgs mechanism and gravity, especially for their different handling of fundamental and composite particles.

Onofrio, Roberto [Dipartimento di Fisica 'Galileo Galilei', Universita di Padova, Via Marzolo 8, Padova 35131 (Italy) and ITAMP, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138 (United States)

2010-09-15T23:59:59.000Z

487

Asymptotic safety of gravity and the Higgs boson mass  

E-Print Network (OSTI)

There are indications that gravity is asymptotically safe. The Standard Model (SM) plus gravity could be valid up to arbitrarily high energies. Supposing that this is indeed the case and assuming that there are no intermediate energy scales between the Fermi and Planck scales we address the question of whether the mass of the Higgs boson $m_H$ can be predicted. For a positive gravity induced anomalous dimension $A_\\lambda>0$ the running of the quartic scalar self interaction $\\lambda$ at scales beyond the Planck mass is determined by a fixed point at zero. This results in $m_H=m_{\\rm min}=126$ GeV, with only a few GeV uncertainty. This prediction is independent of the details of the short distance running and holds for a wide class of extensions of the SM as well. For $A_\\lambda 0$ is favored by explicit computations existing in the literature.

Mikhail Shaposhnikov; Christof Wetterich

2009-12-01T23:59:59.000Z

488

Anisotropic stress and stability in modified gravity models  

Science Conference Proceedings (OSTI)

The existence of anisotropic stress of a purely geometrical origin seems to be a characteristic of higher order gravity models, and has been suggested as a probe to test these models observationally, for example, in weak lensing experiments. In this paper, we seek to find a class of higher order gravity models of f(R,G) type that would give us a zero anisotropic stress and study the consequences for the viability of the actual model. For the special case of a de Sitter background, we identify a subclass of models with the desired property. We also find a direct link between anisotropic stress and the stability of the model as well as the presence of extra degrees of freedom, which seems to be a general feature of higher order gravity models. Particularly, setting the anisotropic stress equal to zero for a de Sitter background leads to a singularity that makes it impossible to reach the de Sitter evolution.

Saltas, Ippocratis D. [Astronomy Centre, University of Sussex, Falmer, Brighton BN1 9QH (United Kingdom); Kunz, Martin [Departement de Physique Theorique, Universite de Geneve, 1211 Geneva 4 (Switzerland)

2011-03-15T23:59:59.000Z

489

Building an American Economy to Last: American Competiveness in  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Building an American Economy to Last: American Competiveness in Building an American Economy to Last: American Competiveness in Manufacturing Building an American Economy to Last: American Competiveness in Manufacturing August 16, 2012 - 9:20am Addthis Saving Energy and Resources 1 of 4 Saving Energy and Resources Thanks to additive manufacturing technology, Oak Ridge National Laboratory was able to fabricate a robotic hand with less energy use and material waste. The novel, lightweight, low-cost fluid powered hand was selected for a 2012 R&D 100 award. | Photo courtesy of Oak Ridge National Laboratory. Partnering with Industry 2 of 4 Partnering with Industry The Energy Department's Manufacturing Demonstration Facility at Oak Ridge National Laboratory includes an array of state-of-the-art additive manufacturing capabilities, allowing researchers and industry to develop

490

Building an American Economy to Last: American Competiveness in  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Building an American Economy to Last: American Competiveness in Building an American Economy to Last: American Competiveness in Manufacturing Building an American Economy to Last: American Competiveness in Manufacturing August 16, 2012 - 9:20am Addthis Saving Energy and Resources 1 of 4 Saving Energy and Resources Thanks to additive manufacturing technology, Oak Ridge National Laboratory was able to fabricate a robotic hand with less energy use and material waste. The novel, lightweight, low-cost fluid powered hand was selected for a 2012 R&D 100 award. | Photo courtesy of Oak Ridge National Laboratory. Partnering with Industry 2 of 4 Partnering with Industry The Energy Department's Manufacturing Demonstration Facility at Oak Ridge National Laboratory includes an array of state-of-the-art additive manufacturing capabilities, allowing researchers and industry to develop

491

Angular momentum extraction by gravity waves in the Sun  

E-Print Network (OSTI)

We review the behavior of the oscillating shear layer produced by gravity waves below the surface convection zone of the Sun. We show that, under asymmetric filtering produced by this layer, gravity waves of low spherical order, which are stochastically excited at the base of the convection zone of late type stars, can extract angular momentum from their radiative interior. The time-scale for this momentum extraction in a Sun-like star is of the order of 10^7 years. The process is particularly efficient in the central region, and it could produce there a slowly rotating core.

Suzanne Talon; Pawan Kumar; Jean-Paul Zahn

2002-06-27T23:59:59.000Z

492

ENVIRONMENT DEPENDENCE OF DARK MATTER HALOS IN SYMMETRON MODIFIED GRAVITY  

Science Conference Proceedings (OSTI)

We investigate the environment dependence of dark matter halos in the symmetron modified gravity scenario. The symmetron is one of three known mechanisms for screening a fifth force and thereby recovering general relativity in dense environments. The effectiveness of the screening depends on both the mass of the object and the environment it lies in. Using high-resolution N-body simulations we find a significant difference, which depends on the halo's mass and environment, between the lensing and dynamical masses of dark matter halos similar to the f(R) modified gravity. The symmetron can however yield stronger signatures due to a freedom in the strength of coupling to matter.

Winther, Hans A.; Mota, David F. [Institute of Theoretical Astrophysics, University of Oslo, NO-0315 Oslo (Norway); Li Baojiu [ICC, Department of Physics, University of Durham, South Road, Durham DH1 3LE (United Kingdom)

2012-09-10T23:59:59.000Z

493

Time machines and traversable wormholes in modified theories of gravity  

E-Print Network (OSTI)

We review recent work on wormhole geometries in the context of modified theories of gravity, in particular, in f(R) gravity and with a nonminimal curvature-matter coupling, and in the recently proposed hybrid metric-Palatini theory. In principle, the normal matter threading the throat can be shown to satisfy the energy conditions and it is the higher order curvatures terms that sustain these wormhole geometries. We also briefly review the conversion of wormholes into time-machines, explore several of the time travel paradoxes and possible remedies to these intriguing side-effects in wormhole physics.

Francisco S. N. Lobo

2012-12-05T23:59:59.000Z

494

Spherically symmetric static spacetimes in vacuum f(T) gravity  

SciTech Connect

We show that Schwarzschild geometry remains as a vacuum solution for those four-dimensional f(T) gravitational theories behaving as ultraviolet deformations of general relativity. In the gentler context of three-dimensional gravity, we also find that the infrared-deformed f(T) gravities, like the ones used to describe the late cosmic speed up of the Universe, have as the circularly symmetric vacuum solution a Deser-de Sitter or a Banados, Teitelboim and Zanelli-like spacetime with an effective cosmological constant depending on the infrared scale present in the function f(T).

Ferraro, Rafael [Instituto de Astronomia y Fisica del Espacio, Casilla de Correo 67, Sucursal 28, 1428 Buenos Aires (Argentina); Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon I, 1428 Buenos Aires (Argentina); Fiorini, Franco [Instituto de Astronomia y Fisica del Espacio, Casilla de Correo 67, Sucursal 28, 1428 Buenos Aires (Argentina)

2011-10-15T23:59:59.000Z

495

Generalized Teleparallel Gravity Via Some Scalar Field Dark Energy Models  

E-Print Network (OSTI)

We consider generalized teleparallel gravity in the flat FRW universe with a viable power-law f(T) model. We construct its equation of state and deceleration parameters which give accelerated expansion of the universe in quintessence era for the obtained scale factor. Further, we develop correspondence of f(T) model with scalar field models such as, quintessence, tachyon, K-essence and dilaton. The dynamics of scalar field as well as scalar potential of these models indicate the expansion of the universe with acceleration in the f(T) gravity scenario.

M. Sharif; Shamaila Rani

2013-11-25T23:59:59.000Z

496

Renormalizable Quantum Gravity in Low Energy without Violating Unitarity  

E-Print Network (OSTI)

We introduce new techniques that can preserve unitarity of the system including ghost particles. Negative norms of the particles can be involved in zero-norm states by constraints of the physical space. These are useful to apply the higher-derivative propagator for quantum gravity to suppress divergences of vacuum energy and graviton mass correction. The quantum effects are mainly depending on the ghost mass scale. As the scale can be chosen in any order, the observed cosmological constant is realized. Further, applying ghost partners for the standard model particles, quantum gravity with matter fields becomes renormalizable with power counting arguments.

Hajime Isimori

2010-10-25T23:59:59.000Z

497

On the Origin of Gravity, Dark Energy and Matter.  

E-Print Network (OSTI)

Insights from black hole physics and developments in string theory strongly indicate that the gravity is derived from an underlying microscopic description in which it has no a priori meaning. Starting from first principles we argue that inertia and gravity are caused by the fact that phase space volume (or entropy) associated with the underlying microscopic system is influenced by the positions of material objects. Application of these ideas to cosmology leads to surprising new insights into the nature of dark energy and dark matter.

CERN. Geneva

2011-01-01T23:59:59.000Z

498

Self-dual teleparallel gravity and the positive energy theorem  

E-Print Network (OSTI)

A self-dual and anti-self-dual decomposition of the teleparallel gravity is carried out and the self-dual Lagrangian of the teleparallel gravity which is equivalent to the Ashtekar Lagrangian in vacuum is obtained. Its Hamiltonian formulation and the constraint analysis are developed. Starting from Witten's equation Nester's gauge condition is derived directly and a new expression of the boundary term is obtained. Using this expression and Witten's identity the proof of the positive energy theorem by Nester et al is extended to a case including momentum.

G. Y. Chee

2004-08-16T23:59:59.000Z

499

Baryogenesis in $f(R)$-Theories of Gravity  

E-Print Network (OSTI)

$f(R)$-theories of gravity are reviewed in the context of the so called gravitational baryogenesis. The latter is a mechanism for generating the baryon asymmetry in the Universe, and relies on the coupling between the Ricci scalar curvature $R$ and the baryon current. Gravity Lagrangians of the form ${\\cal L}(R)\\sim R^n$, where $n$ differs from 1 (the case of the General Relativity) only for tiny deviations of a few percent, are consistent with the current bounds on the observed baryon asymmetry.

G. Lambiase; G. Scarpetta

2006-10-12T23:59:59.000Z

500

Viscoelastic Suppression of Gravity-Driven Counterflow Instability  

E-Print Network (OSTI)

Attempts to achieve ``top kill'' of actively flowing oil wells by insertion of dense drilling ``muds'', i.e., slurries of dense minerals, from above will fail if the Kelvin-Helmholtz instability in the gravity-driven counterflow produces turbulence that breaks up the denser fluid into small droplets. Here we estimate the droplet size to be sub-mm for fast flows and suggest the addition of a shear-thickening polymer to suppress turbulence. Laboratory experiments show a progression from droplet formation to complete turbulence suppression at the relevant high velocities, illustrating rich new physics accessible by using a shear-thickening liquid in gravity driven counter-streaming flows.

Beiersdorfer, P; Layne, D; Magee, E W

2010-01-01T23:59:59.000Z