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1

Preprocessing of gravity gradients at the GOCE high-level processing facility  

Microsoft Academic Search

One of the products derived from the gravity field and steady-state ocean circulation explorer (GOCE) observations are the gravity gradients. These gravity gradients are provided in the gradiometer reference frame (GRF) and are calibrated in-flight using satellite shaking and star sensor data. To use these gravity gradients for application in Earth scienes and gravity field analysis, additional preprocessing needs to

J. Bouman; S. Rispens; T. Gruber; R. Koop; E. Schrama; P. Visser; C. C. Tscherning; M. Veicherts

2008-01-01

2

Preprocessing of gravity gradients at the GOCE high-level processing facility  

Microsoft Academic Search

One of the products derived from the gravity field and steady-state ocean circulation explorer (GOCE) observations are the\\u000a gravity gradients. These gravity gradients are provided in the gradiometer reference frame (GRF) and are calibrated in-flight\\u000a using satellite shaking and star sensor data. To use these gravity gradients for application in Earth scienes and gravity\\u000a field analysis, additional preprocessing needs to

Johannes Bouman; Sietse Rispens; Thomas Gruber; Radboud Koop; Ernst Schrama; Pieter Visser; Carl Christian Tscherning; Martin Veicherts

2009-01-01

3

High Spin Topologically Massive Gravity  

NASA Astrophysics Data System (ADS)

We study the high spin fields coupled to topologically massive gravity in AdS3, paying special attention to the nature of the theory at the critical point. We propose an action incorporating the high spin AdS3 gravity and the topological Chern-Simons term for high spin fields. We discuss the fluctuation spectrum around the AdS3 vacuum and find that besides the usual massless modes there are local massive modes.

Chen, Bin

2012-12-01

4

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

SciTech Connect

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

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

1988-12-31

5

Viscous Stabilization of Gravity Wave Critical Level Flows  

Microsoft Academic Search

A criterion for the viscous stabilization of gravity wave critical level flow is derived to be Z 1\\/4 2.5 Zr where Z 1\\/4 is the vertical thickness of the unstable region in the vicinity of a gravity wave critical level calculated with an inviscid linear theory and Zy is the viscous length scale for gravity wave critical level interaction. The

David C. Fritts; Marvin A. Geller

1976-01-01

6

The Constant Levelers: Water, Ice, and Gravity  

NSDL National Science Digital Library

This site has information about the work of three of the agents of erosion in the Northern Cascade Range. Since much of the range is made up of exotic terrains that probably did not evolve on the same spot on the Earth as the present North Cascades, the geologists confine their view to some time since the earliest Tertiary. Within that time frame, they can speculatively recreate the North Cascade scene and ponder its erosional history. The erosional work of rivers has constantly been altered by volcanic activity and whatever drainage pattern was established. It was profoundly altered about 35 million years ago by the renewed volcanic activity of the Cascade Volcanic Arc. A section about how rivers erode describes differential erosion, stream capture, and base level. The section about glaciers explains how they are formed, how they do their work, and what is left behind. The section about the work of gravity focuses on creep and landslides.

7

Effects of high gravity on amphibian development.  

PubMed

In order to clarify the possible effects of high gravity environments on eggs and developing embryos, Rana rugosa and Xenopus laevis fertilized eggs and early embryos were raised in 2 G, 5 G, 7 G and 10 G up to the hatched tadpole stage. The results showed that: (1) High gravity significantly retarded the development of eggs and embryos beginning treatment before the blastula stage and induced various abnormalities, including two heads and microcephally suggesting that high gravity is apt to disrupt the animal-vegital axis. On the other hand, embryos beginning treatment after the gastrula stage showed a striking increase in the number of normal-appearing feeding tadpoles. (2) Autopsy revealed that brains, notochords and muscles were reduced in development and differentiation for embryos and tadpoles developed in high gravity. (3) It seems likely that the system for hydrogen peroxide detoxification develops abnormally in high gravity-treated embryos and tadpoles, which probably results in oxidative stress, leading to considerable cell damage. PMID:14676383

Kashiwagi, Akihiko; Hanada, Hideki; Kawakami, Satomi; Kubo, Hideo; Shinkai, Tadashi; Fujii, Hirotada; Kashiwagi, Keiko

2003-10-01

8

Validation of GOCE time-wise gravity field models using GPS-levelling, gravity, vertical deflections and gravity gradient measurements in Hungary  

NASA Astrophysics Data System (ADS)

With the advantage of satellite gravity gradiometry (SGG) high standard global gravity determination could attain in the static part of the gravitational field. This study presents the validation of the first, second and third generation GOCE-only models using terrestrial data sets in Hungary. GOCE global geopotential models (GGM) are consistent models with global coverage (without the unobserved polar caps of 6.5° spherical radius) in sense that GGMs have been compiled utilizing measurements refer to short time period. Besides GOCE-based GGMs satellite only GRACE models were evaluated to assess the improvements by GOCE observations with respect to GRACE in gravity field determination. EGM2008 as the state-of-the-art model and SRTM3 elevation model were applied to provide that measurements involving Hungarian data sets and model derived gravity field functionals have almost the same spectral content. Results with GPS-levelling and gravity data support that there is an improvement in the determination of medium wavelength constituents of the gravitational field with GOCE models. Although vertical deflections characterize the short wave part of the gravity field, they are also capable to sense the advancement of SGG observations. Our experiences show that torsion balance measurements depict the fine structure of the gravity field, and hence they are not adequate in low-degree GGM validation.

Sz?cs, E.

2012-04-01

9

The Gravity Model for High School Students  

ERIC Educational Resources Information Center

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

Tribble, Paul; Mitchell, William A.

1977-01-01

10

The Nonlinear Gravity Wave-Critical Level Interaction  

Microsoft Academic Search

A nonlinear numerical model of the gravity wave-critical level interaction is developed in this paper. This model is used to examine and compare the effects of viscosity, time-dependence and nonlinear interactions on the development of the critical level interaction. It is found, in agreement with earlier studies, that viscosity and heat conduction strongly stabilize the interaction very near the critical

David C. Fritts

1978-01-01

11

Validation of GOCE gravity field models over Poland using the EGM2008 and GPS/levelling data  

NASA Astrophysics Data System (ADS)

Since the mid of 2010, global geopotential models based on GOCE mission data became available. The first two releases of GGMs contained four different solutions while in the third release only two solutions have been generated. In the presented study the available GOCE-derived gravity field models were evaluated in terms of height anomalies and gravity anomalies over Poland with the use of the respective functionals calculated from the EGM2008 geopotential model as well as height anomalies at 184 stations of high precision GPS/levelling control traverse. The fit of GOCE gravity field models with the EGM2008 in terms of height anomalies and gravity anomalies measured with a standard deviation is below 10 cm, and 3 mGal, respectively. Their fit with GPS/leveling height anomalies at the stations of GPS/levelling control traverse is at the level of 10 cm. The results obtained indicate some improvement of the consecutive releases of GOCE gravity field models.

Godah, W.; Krynski, J.

2012-06-01

12

Implications of CHAMP gravity field recovery improvement for high-resolution global gravity field models  

NASA Astrophysics Data System (ADS)

New global gravity field models have been derived from CHAMP GPS satellite-to-satellite tracking and accelerometer data resulting in the two models EIGEN-1S and EIGEN-2. Whereas EIGEN-1S incorporates CHAMP plus other satellite tracking data, EIGEN-2 is a CHAMP-only gravity field model. Both models proved to be up to one order more accurate in the long-wavelength part of the gravity model than any pre-CHAMP satellite-only solution. Due to signal attenuation with satellite's altitude, the spectral resolution of the CHAMP models ends at about degree/order 40 corresponding to a spatial resolution of 500 km half wavelength at the Earth surface. The CHAMP-based satellite-only models shall therefore be combined in a rigorous least-squares adjustment with surface gravity data from altimetry and terrestrial gravimetry to achieve a full resolution up to degree/order 120 or 165 km half wavelength. Surface data compilations from NIMA and KMS including newly available polar data are exploited for the combination solution. The resulting model's accuracy pattern is evaluated and the benefit of the improvement of the long-wavelength part thanks to CHAMP is investigated with respect to previous high-resolution global gravity field models. ~

Reigber, Ch.; Schwintzer, P.; Balmino, G.; Biancale, R.; Eigen Team

2003-04-01

13

Calibration of GOCE SGG data using high–low SST, terrestrial gravity data and global gravity field models  

Microsoft Academic Search

It is the aim of the GOCE mission to determine a model of the Earth’s gravity field with high accuracy and resolution. For this purpose, gravity gradients will be measured in combination with high–low satellite-to-satellite tracking. The gravity gradients are derived from pair-wise differenced accelerations as determined by the six three-axes accelerometers that form the GOCE gradiometer. Since the measured

J. Bouman; R. Koop; C. C. Tscherning; P. Visser

2004-01-01

14

A Model for High Energy Scattering in Quantum Gravity  

Microsoft Academic Search

We present a model for high energy two body scattering in a quantum theory of gravity. The model is applicable for center of mass energies higher than the relevant Planck scale. At impact parameters smaller than the Schwarzchild radius appropriate to the center of mass energy and total charge of the initial state, the cross section is dominated by an

Tom Banks; Willy Fischler

1999-01-01

15

Production of 21% (v\\/v) ethanol by fermentation of very high gravity (VHG) wheat mashes  

Microsoft Academic Search

Summary Very high gravity wheat mashes containing 300 g or more sugares per liter were prepared by enzymatic hydrolysis of starch and fermented with a commercial preparation of active dry yeast. The active dry yeast used in this study was a blend of several strains ofSaccharomyces cerevisiae. The fermentation was carried out at 20°C at different pitching rates (inoculation levels)

K. C. Thomas; W. M. Ingledew

1992-01-01

16

Turbulent breaking of overturning gravity waves below a critical level  

Microsoft Academic Search

The interaction of an internal gravity wave with its evolving critical layer and the subsequent generation of turbulence by overturning waves are studied by three-dimensional numerical simulations. The simulation describes the flow of a stably stratified Boussinesq fluid between a bottom wavy surface and a top flat surface, both without friction and adiabatic. The amplitude of the surface wave amounts

Andreas Dörnbrack; Thomas Gerz; Ulrich Schumann

1995-01-01

17

Numerical Simulation of Breaking Gravity Waves below a Critical Level  

Microsoft Academic Search

\\u000a The interaction of an internal gravity wave with a critical layer and the generation of turbulence are studied by three-dimensional\\u000a numerical simulations. Based on a successful comparison of a two-dimensional version of the model with experimental observations\\u000a (Thorpe, 1981), we discuss results obtained with two different models of viscosity. Although the variances of the turbulent quantities\\u000a are nearly the same,

Andreas Dörnbrack; Ulrich Schumann

18

Gravity field recovery from in-situ GOCE high-low SST and SGG data  

NASA Astrophysics Data System (ADS)

ESA's GOCE mission was successfully launched on March 17, 2009. The objective of GOCE is to determine the Earth's static gravity field and its anomalies with an accuracy better than 1 mGal, and the global geoid with an accuracy better than 1-2 cm at a spatial resolution of 100 km, from the combination of high-low satellite-to-satellte tracking (hl-SST) and satellite gravity gradiometry (SGG). The hl-SST data of the satellite orbit from the GPS receiver contains the long wavelengths of gravity field, whereas the SGG data from the on-board gradiometer provides more high-frequency information. So an optimum GOCE gravity field model can be derived from the combination processing of these two types of data. In this paper, a GOCE gravity field model complete up to degree/order 200 was recovered using one month (November 2009) of in-situ GOCE Level 2 precise kinematic orbit and gravity gradient data. The gravity field solution strategies are as following: Firstly, the GOCE hl-SST measurements are processed based on the acceleration approach, producing SST normal equations with a maximum degree and order of 90. The satellite acceleration is derived by a 3-points differential scheme, due to the noise of orbit-derived satellite acceleration is colored, the SST normal equations are filtered using a 3-points differential whitening filter. Secondly, the along track of SGG data is processed based on the space-wise least-squares method, producing SGG normal equations with a maximum degree and order of 200. Because of the bandwith limitation (0.005 to 0.1 Hz) of gradiometer measurement, the colored noises in SGG data are processed by a designed ARMA recursive filter in time domain. Thirdly, SST and SGG normal equation systems are combined for GOCE gravity field model adjustment and solved using Cholesky decomposition. The optimal weight ratio for SST/SGG was obtained from variance component estimate (VCE), and the ill-posed problem caused by polar gaps is treated with Kaula regularization strategy. The solution is evaluated through comparison with CHAMP-only, GRACE-only and recently released GOCE-only models, and also some combined models (such as EIGEN-5C and EGM2008). In addation, the solution is also validated with independent GPS/Leveling data in selected areas. Acknowledgement: This research was funded by Key Laboratory of Geo-informatics of State Bureau of Surveying and Mapping (No. 200903), LIESMARS Special Research Funding (2009), the National Natural Science Foundation of China (No. 40874002), and ESA’s Earth Observation Principal Investigator(EOPI) Project (ID.4318).

Zhong, B.; Luo, Z.; Ning, J.; Wang, H.

2010-12-01

19

High potassium levels  

MedlinePLUS

Hyperkalemia; Potassium - high ... The kidneys normally remove excess potassium from the body. High potassium levels are more likely to occur when the kidneys are not working properly and are less ...

20

Wave breaking and critical levels for propagating inertio-gravity waves in the lower stratosphere  

Microsoft Academic Search

This paper analyses and interprets the formation of mixed layers due to propagating inertio-gravity waves observed during the Fronts and Atlantic Storm-Track EXperiment. The data used are high-vertical-resolution soundings launched from different sites located in the North Atlantic sector. In agreement with other studies, attributing the origin of the inertio-gravity waves to the adjustment of the jet stream near fronts,

H. Moldovan; F. Lott; H. Teitelbaum

2002-01-01

21

High level nuclear waste  

SciTech Connect

The DOE Division of Waste Products through a lead office at Savannah River is developing a program to immobilize all US high-level nuclear waste for terminal disposal. DOE high-level wastes include those at the Hanford Plant, the Idaho Chemical Processing Plant, and the Savannah River Plant. Commercial high-level wastes, for which DOE is also developing immobilization technology, include those at the Nuclear Fuel Services Plant and any future commercial fuels reprocessing plants. The first immobilization plant is to be the Defense Waste Processing Facility at Savannah River, scheduled for 1983 project submission to Congress and 1989 operation. Waste forms are still being selected for this plant. Borosilicate glass is currently the reference form, but alternate candidates include concretes, calcines, other glasses, ceramics, and matrix forms.

Crandall, J L

1980-01-01

22

On the nonlinear reflexion of a gravity wave at a critical level. I  

Microsoft Academic Search

An internal gravity wave propagating through a stratified shear flow develops singular characteristics at the critical level where its phase velocity is equal to the mean horizontal velocity of the undisturbed fluid. It has been pointed out in previous studies that in the absence of wave dissipation the nonlinear terms become important in the critical layer after a sufficiently long

S. N. Brown; K. Stewartson

1980-01-01

23

Formation of a turbulent layer by an internal gravity wave near its critical level  

Microsoft Academic Search

The paper examines a possible mechanism for the formation of turbulent layers in the free atmosphere, connected with the nonlinear behavior of internal gravity waves (IGWs) near their critical level. Attention is given to the development of a model of a turbulent layer formed as the result of the breakdown of a weakly nonlinear IGW. Expressions are obtained for the

A. N. Beliaev

1986-01-01

24

Thermal-gravitational modeling and scaling of two-phase heat transport systems from micro-gravity to super-gravity levels  

Microsoft Academic Search

Earlier publications extensively describe NLR research on thermal-gravitational modeling and scaling of two-phase heat transport systems for spacecraft applications. These publications on mechanically and capillary pumped two-phase loops discuss pure geometric scaling, pure fluid to fluid scaling, and combined (hybrid) scaling of a prototype system by a model at the same gravity level, and of a prototype in micro-gravity environment

A. A. M. Delil

2001-01-01

25

Changing gravity level and the development of animals.  

PubMed

Space biology has accumulated a great body of information concerning the influence of microgravity upon objects of varying levels of biological organization: from microorganisms to higher animals and humans. However, the choice of biological objects was in most cases random, and there has been no attempt at a comparative biological analysis of the results obtained. A similar situation is noted in hypergravity research, where responses in various animal classes are compared mainly with respect to differences in body masses rather than in the level of biological organization. Without any claims to solve this serious problem in this presentation, I'll try to at least raise it, using as a starting point the conception about evolution of resistance and reactivity, created by my teacher N.N. Sirotinin (1981). PMID:11538526

Serova, L V

1993-02-01

26

High gravity fermentation of sugarcane molasses to produce ethanol: Effect of nutrients  

Microsoft Academic Search

Fermentation efficiency of more than 85% was obtained by high gravity fermentation of 33–34°Bx (spec. gravity ?1.134) molasses\\u000a medium with certain nutrients, instead of generally employed medium containing ?16% (w\\/v) total sugar (spec. gravity ?1.090)\\u000a for ethanol fermentation in distilleries to get maximum 80–85% conversion. The fermenting yeast, Saccharomyces, has varied capabilities, depending on the species and nutrition for fermenting

P. Pradeep; O. V. S. Reddy

2010-01-01

27

High precision levelling supporting the International Comparison of Absolute Gravimeters  

Microsoft Academic Search

High precision levelling is an indispensable method used to monitor benchmark and terrain stability at the Bureau International des Poids et Mesures (BIPM). Associated with the International Comparison of Absolute Gravimeters (ICAG), levelling measurements were carried out repeatedly over the past decades. A local gravity field strongly depends on vertical terrain deformation. 1 cm displacement implies about 2 µGal change

Z Jiang; M Becker; P Jousset; A Coulomb; L Tisserand; P Boulanger; D Lequin; F Lhermitte; J L Houillon; F Dupont

2012-01-01

28

THE STATISTICAL FIT OF HIGH DEGREE GEOPOTENTIAL MODELS TO THE GRAVITY FIELD OF AUSTRALIA  

Microsoft Academic Search

Precise regional geoid determinations are usually carried out using a global geopotential model, together with a set of point or mean terrestrial gravity anormalies and topographic information. In order to determine the most suitable geopotential model for this combination, the statistical fit of several high degree models to the gravity field of Australia is studied. This comprises the fit of

K. F. Zhang; W. E. Featherstone

29

Arctic margin gravity highs: Deeper meaning for sediment depocenters?  

Microsoft Academic Search

Morphologic, gravity, and seismic reflection\\/refraction data from ca. 10,000 km of Arctic passive continental margins suggest that the numerous oval free-air gravity anomalies, their +50–150 mGal extrema typically located just landward of shelf breaks, are caused by combinations of rapidly deposited Plio-Pleistocene glacial marine sediment loads, older post-breakup sediments, and perhaps causally related density anomalies (mascons) in the underlying oceanic crust. Dispersed

Peter R. Vogt; Woo-Yeol Jung; John Brozena

1998-01-01

30

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

NASA Astrophysics Data System (ADS)

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

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

2012-07-01

31

Gravity Field Recovery from GOCE High-low SST and SGG Data by the Combined Adjustment Method  

NASA Astrophysics Data System (ADS)

ESA's GOCE (Gravity field and steady-state Ocean Circulation Explorer) mission is based on the sensor concepts of high-low satellite-to-satellite tracking (SST-hl) and satellite gravity gradiometry (SGG). The SST-hl data from GPS receiver contains the long wavelengths of gravity field, and the SGG data from gradiometer provides more high-frequency information. Therefore, an optimal GOCE gravity field solution can be derived from the combination processing of these two types of data. The combination processing is based on the method of least squares combined adjustment, and an Earth gravity field model complete up to degree/order 200 is recovered from 71 days of GOCE precise kinematic orbit and gravity gradient data. The gravity field solution strategies are as following: Firstly, the SST-hl data is processed based on the acceleration approach, which produces the SST-hl normal equations with a maximum degree and order of 100. The satellite accelerations are derived by a 3-points differential scheme, and the colored noises in orbit-derived satellite acceleration data are filtered using a 3-points differential whitening filter. Secondly, the along track of SGG data is processed based on the space-wise least-squares method, which produces the SGG normal equations with a maximum degree and order of 200. Due to the systematic behavior (mainly in 1cpr) and bandwidth limitation (0.005 to 0.1 Hz) of gradiometer measurement, the system errors and colored noises in SGG data are processed by the designed mean filter and ARMA recursive filter, respectively. Thirdly, SST-hl and SGG normal equations are combined for GOCE gravity field model adjustment, and the superposition of normal equation system is solved using Cholesky decomposition. The optimal weight ratio for SST-hl/SGG is obtained from variance component estimate (VCE), and the ill-posed problem caused by polar gaps is treated with Kaula regularization strategy. The solution is evaluated through comparison with the first released GOCE-only models, and it is also validated by independent GPS/Leveling data in the selected areas of China. The results show that our solution is more accurate than the GOCE time-wise solution, and its total accuracy is most close to the GOCE space-wise solution. Key words: gravity field recovery, combination adjustment, GOCE Acknowledgement: This research was supported by the National Natural Science Foundation of China (No.41131067, No.41104014), China Postdoctoral Science Foundation (No. 20110491189), and ESA's Earth Observation Principal Investigator (EOPI) Project (ID.4318)

Zhong, B.; Luo, Z. C.; Li, J. C.; Wang, H. H.

2012-04-01

32

High gravity batch and continuous processes for beer production: Evaluation of fermentation performance and beer quality  

Microsoft Academic Search

This study deals with two innovative brewing processes, high gravity batch and complete continuous beer fermentation systems.\\u000a The results show a significant influence of the variables such as concentration and temperature on the yield factor of the\\u000a substrate into ethanol and consequently on the productivity of the high gravity batch process. The technological feasibility\\u000a of continuous production of beer based

Daniel P. Silva; Tomáš Brányik; Giuliano Dragone; António A. Vicente; José A. Teixeira; João B. Almeida e Silva

2008-01-01

33

Synoptic-scale variability of arctic gravity wave activity during summer and potential impacts on the high latitude middle atmosphere  

Microsoft Academic Search

Although the role of gravity waves in the global atmospheric circulation is generally understood, discussion of synoptic gravity wave activity, especially pertaining to high latitude summer environments, is lacking in the literature. Tropospherically generated gravity waves greatly contribute to the zonal drag necessary to induce meridional outflow and subsequent upwelling observed in the adiabatically cooled summer mesosphere, ultimately resulting in

Andrew John Gerrard

2002-01-01

34

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

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

35

Revealing the beneficial effect of protease supplementation to high gravity beer fermentations using \\  

Microsoft Academic Search

Background  Addition of sugar syrups to the basic wort is a popular technique to achieve higher gravity in beer fermentations, but it\\u000a results in dilution of the free amino nitrogen (FAN) content in the medium. The multicomponent protease enzyme Flavourzyme\\u000a has beneficial effect on the brewer's yeast fermentation performance during high gravity fermentations as it increases the\\u000a initial FAN value and

Maya P Piddocke; Alessandro Fazio; Wanwipa Vongsangnak; Man L Wong; Hans P Heldt-Hansen; Chris Workman; Jens Nielsen; Lisbeth Olsson

2011-01-01

36

High-resolution 2D and 3D numerical simulations of gravity currents  

Microsoft Academic Search

Gravity currents are essentially horizontal motion of fluids of different density in a gravitational field and their spreading behaviors are characterized by the relative balance of buoyancy, inertial and viscous forces. High resolution numerical simulations of two- and three-dimensional (2D and 3D) gravity currents are carried out using the unsteady Reynolds-averaged Navier-Stokes (URANS) closed by the buoyancy-extended turbulence model. The

Afshin Eghbalzadeh; Joongcheol Paik; Fotis Sotiropoulos

2006-01-01

37

High-Gravity Brewing: Effects of Nutrition on Yeast Composition, Fermentative Ability, and Alcohol Production  

PubMed Central

A number of economic and product quality advantages exist in brewing when high-gravity worts of 16 to 18% dissolved solids are fermented. Above this level, production problems such as slow or stuck fermentations and poor yeast viability occur. Ethanol toxicity has been cited as the main cause, as brewers' yeasts are reported to tolerate only 7 to 9% (vol/vol) ethanol. The inhibitory effect of high osmotic pressure has also been implicated. In this report, it is demonstrated that the factor limiting the production of high levels of ethanol by brewing yeasts is actually a nutritional deficiency. When a nitrogen source, ergosterol, and oleic acid are added to worts up to 31% dissolved solids, it is possible to produce beers up to 16.2% (vol/vol) ethanol. Yeast viability remains high, and the yeasts can be repitched at least five times. Supplementation does not increase the fermentative tolerance of the yeasts to ethanol but increases the length and level of new yeast cell mass synthesis over that seen in unsupplemented wort (and therefore the period of more rapid wort attenuation). Glycogen, protein, and sterol levels in yeasts were examined, as was the importance of pitching rate, temperature, and degree of anaerobiosis. The ethanol tolerance of brewers' yeast is suggested to be no different than that of sake or distillers' yeast.

Casey, Gregory P.; Magnus, Carol A.; Ingledew, W. M.

1984-01-01

38

Regional and global gravity models from the analysis of GOCE level-1b data  

NASA Astrophysics Data System (ADS)

ESA's GOCE satellite mission delivers accurate data of high resolution and nearly global coverage. The standard approach is to analyse these observations using the globally defined spherical harmonic functions. However, regional (radial) base functions provide the advantage to be more flexible in modelling data of differing density and variability, which clearly is the case for satellite gravity data. Particularly, a regionally adapted regularisation process enables optimal damping of both, regions featuring rough signal and rather smooth areas, at the same time. This is of special interest for GOCE because of its strength in observing the high frequency part of the gravity field. The present paper represents the final results of the project GLOREGOCE which is part of the German funded research programme REAL GOCE. The project mainly aims at providing regionally refined gravity field models by applying the short arc approach on GOCE orbit and (pure) gradiometer data. For easy investigation, regional solutions calculated on small patches all over the globe have been merged and transformed to a spherical harmonic expansion by means of quadrature methods. The power of the regional approach is demonstrated by comparison to spherical harmonic models, which are based on exactly the same processing strategy, standards and data time span. We show, that these global models are comparable in accuracy with respect to the official GOCE models published by ESA. Moreover, we will show that regional models perform even better compared to global models in the higher frequencies: In oceanic areas, the regionally adapted regularisation process leads to a noise reduction of about 10%. A more tailored choice of the regularisation areas tested for the South Sandwich Trench reveals improvements that are nearly twice as large.

Schall, Judith; Eicker, Annette; Kusche, Jürgen

2013-04-01

39

High energy behavior of gravity at large N  

SciTech Connect

A first step in the analysis of the renormalizability of gravity at large N is carried out. Suitable resummations of planar diagrams give rise to a theory in which there is only a finite number of primitive, superficially divergent, Feynman diagrams. The mechanism is similar to the one which makes the 3D Gross-Neveu model renormalizable at large N. The connections with gravitational confinement and Kawai-Lewellen-Tye relations are briefly analyzed. Some potential problems in fulfilling the Zinn-Justin equations are pointed out.

Canfora, F. [Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, GC di Salerno, Dipartimento di Fisica 'E. R. Caianiello', Universita di Salerno, Via S. Allende, 84081 Baronissi (Salerno) (Italy)

2006-09-15

40

High?degree gravity models from GRAIL primary mission data  

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

41

Glacier mass balance in high-arctic areas with anomalous gravity  

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

42

A Fast Full Tensor Gravity computation algorithm for High Resolution 3D Geologic Interpretations  

NASA Astrophysics Data System (ADS)

We present an algorithm to rapidly calculate the vertical gravity and full tensor gravity (FTG) values due to a 3-D geologic model. This algorithm can be implemented on single, multi-core CPU and graphical processing units (GPU) architectures. Our technique is based on the line element approximation with a constant density within each grid cell. This type of parameterization is well suited for high-resolution elevation datasets with grid size typically in the range of 1m to 30m. The large high-resolution data grids in our studies employ a pre-filtered mipmap pyramid type representation for the grid data known as the Geometry clipmap. The clipmap was first introduced by Microsoft Research in 2004 to do fly-through terrain visualization. This method caches nested rectangular extents of down-sampled data layers in the pyramid to create view-dependent calculation scheme. Together with the simple grid structure, this allows the gravity to be computed conveniently on-the-fly, or stored in a highly compressed format. Neither of these capabilities has previously been available. Our approach can perform rapid calculations on large topographies including crustal-scale models derived from complex geologic interpretations. For example, we used a 1KM Sphere model consisting of 105000 cells at 10m resolution with 100000 gravity stations. The line element approach took less than 90 seconds to compute the FTG and vertical gravity on an Intel Core i7 CPU at 3.07 GHz utilizing just its single core. Also, unlike traditional gravity computational algorithms, the line-element approach can calculate gravity effects at locations interior or exterior to the model. The only condition that must be met is the observation point cannot be located directly above the line element. Therefore, we perform a location test and then apply appropriate formulation to those data points. We will present and compare the computational performance of the traditional prism method versus the line element approach on different CPU-GPU system configurations. The algorithm calculates the expected gravity at station locations where the observed gravity and FTG data were acquired. This algorithm can be used for all fast forward model calculations of 3D geologic interpretations for data from airborne, space and submarine gravity, and FTG instrumentation.

Jayaram, V.; Crain, K.; Keller, G. R.

2011-12-01

43

Einstein Gravity from Conformal Gravity  

Microsoft Academic Search

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

Juan Maldacena

2011-01-01

44

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

45

Non-Boussinesq axisymmetric gravity currents at high Re  

NASA Astrophysics Data System (ADS)

The propagation of a non-Boussinesq gravity current in an axisymmetric configuration (full cylinder or wedge) is considered. The current of density ?c is released from rest from a lock of radius r0 and height h0 into an ambient fluid of density ?a in a container of height H, adjacent to the horizontal boundary on which propagation occurs. When the Reynolds number Re is large, the resulting flow is governed by the parameters ?c/?a and H^* = H/h0. We show that the shallow-water one layer model, carefully combined with a Benjamin-type front condition, provides a versatile formulation for the thickness and speed of the current, for a wide range of the parameters, without any adjustable constants. (The Boussinesq currents are just a small subdomain about ?c/?a= 1 of this solution). Comparisons with Navier-Stokes solutions and differences with the 2D rectangular counterpart (Ungarish, J. Fluid Mech. 579, 373-382, 2007) are discussed.

Ungarish, Marius

2009-11-01

46

Could quantum gravity phenomenology be tested with high intensity lasers?  

SciTech Connect

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

Magueijo, Joao [Perimeter Institute for Theoretical Physics, 31 Caroline Street North, Waterloo N2L 2Y5 (Canada); Canadian Institute for Theoretical Astrophysics, 60 St. George Street, Toronto M5S 3H8 (Canada); Theoretical Physics Group, Imperial College, Prince Consort Road, London SW7 2BZ (United Kingdom)

2006-06-15

47

Characteristics of high-frequency gravity waves generated by tropical deep convection: Case studies  

NASA Astrophysics Data System (ADS)

High-frequency gravity waves generated by tropical deep convection play a major role in shaping the general circulation of the middle atmosphere. Special experiments were conducted to capture two convective events on 16 May and 5 June 2006 using VHF radar located at Gadanki (13.5°N, 79.2°E), a tropical Indian station. Control day observations were also made for necessary comparisons. Background wind and temperature information was obtained by GPS radiosonde flights launched from the same site. This work has utilized these valuable data sets to delineate characteristics of convectively generated gravity waves. A superposition of gravity waves is observed with different scales after the deep convective events. Vertical wave number spectra of radial velocities show steeper slopes and higher power spectral densities during convection which slowly reduce to their normal values. The present case studies suggest the mechanical oscillator mechanism to be a major source of convective gravity wave generation in the tropics. Estimates of vertical wind variances and momentum fluxes of short-period (<2 h) wind fluctuations show large enhancements on convective days in comparison to control days. The momentum flux frequency spectra revealed a higher contribution of 30-65 min wave periods to the mean profile in the lower stratosphere. The wavelet transform momentum flux spectra displayed the temporal variability and discretization of the gravity wave momentum fluxes in frequency and time.

Dutta, Gopa; Ajay Kumar, M. C.; Vinay Kumar, P.; Venkat Ratnam, M.; Chandrashekar, M.; Shibagaki, Y.; Salauddin, M.; Basha, H. A.

2009-09-01

48

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

NASA Astrophysics Data System (ADS)

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

Odera, P. A.; Fukuda, Y.; Kuroishi, Y.

2012-05-01

49

Exploratory Study of Arm-Reach Dynamics under Several Levels of Gravity.  

National Technical Information Service (NTIS)

Four adult male subjects made vertical reaching movements, upward and downward, over 10, 20, and 30 in. distances; these movements were performed under weightlessness (0.0g), Martian gravity (0.38g), Earth gravity (1.0g), and 1.3G. The subject's arm was c...

N. M. Aume

1973-01-01

50

Enhanced oil recovery - steam. Low gravity, high viscosity oil is target of New Mexico's first pilot  

Microsoft Academic Search

New Mexico's first pilot steamflood was begun in Guadalupe County in hopes of recovering low gravity (17 API), high viscosity (1400 cp at 75 F) crude from the Santa Rosa formation of Triassic age. Project plans call for 60 to 100 bwpd to be converted into steam and injection into the formation which lies at ca. 400 ft. Injection began

Wash

1982-01-01

51

The Effect of Pitching Rate on Fermentation and Flavour Compounds in High Gravity Brewing  

Microsoft Academic Search

J. Inst. Brew. 113(1), 75-79, 2007 The effect of pitching rate on fermentation and production of flavour compounds was studied in high gravity wort using a lager yeast. Fermentation performance was followed by moni- toring the total sugar content and yeast growth. Volatile com- pounds were evaluated by analysing higher alcohols, esters and carbonyl compounds at the end of fermentation.

Huseyin Erten; Hasan Tanguler; Hanife Cakiroz

52

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

PubMed Central

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

2013-01-01

53

Development of redox potential-controlled schemes for very-high-gravity ethanol fermentation.  

PubMed

Fermentation redox potential reflects the momentary physiological status of organisms. Controlling redox potential can modulate the redistribution of intracellular metabolic flux to favor the formation of the desired metabolite. Accordingly, we have developed three redox potential-controlled schemes to maximize their effects on the very-high-gravity (VHG) ethanol fermentation. They are aeration-controlled scheme (ACS), glucose-controlled feeding scheme (GCFS), and combined chemostat and aeration-controlled scheme (CCACS). These schemes can maintain fermentation redox potential at a prescribed level (i.e., -50, -100, and -150 mV) by supplementing sterile air, fresh glucose media, or a combination of sterile air and fresh glucose media into a fermenter to counteract the decline of redox potential due to yeast growth. When ACS was employed, the fermentation efficiency at -150 mV is superior to the other two redox potential levels especially when the initial glucose concentration is higher than 250 g/l. The redox potential-controlled period for ACS, GCFS, and CCACS at -150 mV under the same 200 g glucose/l condition was 2.5, 21.7 and 64.6h and the corresponding fermentation efficiency was 85.9,89.3 and 92.7%, respectively. PMID:21419814

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

2011-03-17

54

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

PubMed

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

Pereira, Francisco B; Gomes, Daniel G; Guimarães, Pedro M R; Teixeira, José A; Domingues, Lucília

2011-09-06

55

Wafer-Level Integration Technique of Surface Mount Devices on a Si-Wafer With Vibration Energy and Gravity Force  

Microsoft Academic Search

This paper reports about a novel wafer-level integration technique of discrete surface mount devices (SMDs). It enables wafer-level mounting of plural kinds of SMDs on a silicon (Si)-wafer using vibration and gravity force. Deep holes with 400-m depth are formed on the surface of a Si-wafer by deep reactive ion etching process after general integrated circuit process for positioning of

Minoru Sudou; Hidekuni Takao; Kazuaki Sawada; Makoto Ishida

2007-01-01

56

An Exploratory Study of Arm-Reach Dynamics Under Several Levels of Gravity  

Microsoft Academic Search

Four adult male subjects made vertical reaching movements, upward and downward, over 10, 20, and 30 in. distances; these movements were performed under weightlessness (0-0g), Martian gravity (0-38g), Earth gravity (l-0g), and 1-3G. The movements were recorded with a movie camera running at 64 frames per second. The subject's arm was considered as consisting of two rigid parts: the upper

N. M. AUME

1973-01-01

57

High pressure liquid level monitor  

DOEpatents

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

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

1984-01-01

58

Experimental evaluation of perfluorophenanthrene as a high specific gravity vitreous substitute: a preliminary report.  

PubMed

Perfluorophenanthrene, a liquid fluorocarbon with a specific gravity approximately twice that of water, potentially offers certain advantages as a vitreous substitute in vitreoretinal surgery. To determine its efficacy and safety we first purified it by chemical methods used in the preparation of experimental blood substitutes to a level at which it was not at all or only minimally toxic to culture-grown retinoblastoma cells. Nineteen of 22 vitrectomized eyes of white New Zealand rabbits injected with this purified perfluorophenanthrene showed satisfactory clinical tolerance. Light and electron microscopy showed minimal or no toxic effects in the 19 eyes, although uptake of perfluorophenanthrene by some preretinal cells was observed 28 days after implantation. Postoperative light-adapted electroretinography recordings of eight of the injected eyes showed no significant change. Perfluorophenanthrene injected into the anterior chamber of the rabbit eyes had toxic effects on the cornea. If further experimentations confirm our findings, perfluorophenanthrene may be a suitable transparent high-density liquid for temporary use in surgery to repair retinal detachments. PMID:2733997

Nabih, M; Peyman, G A; Clark, L C; Hoffman, R E; Miceli, M; Abou-Steit, M; Tawakol, M; Liu, K R

1989-04-01

59

Gravity wave momentum flux variability in the high latitude northern hemisphere winter mesosphere/lower thermosphere  

NASA Astrophysics Data System (ADS)

A new SKiYMET meteor radar was installed in Trondheim, Norway (63°N, 10°E) and has been operational since August 2012. The 30 kW transmitter array directs most of the radar power into eight beams at 45° azimuth increments with peak power around 35° off zenith, and a majority of meteor detections at zenith angles between 15° and 50°. High meteor count rates of up to 15000 per day are observed in the mesosphere and lower thermosphere region between 75 and 105 km altitude. The high meteor count rates, combined with the beam geometry, make the system particularly well suited for measuring horizontal winds at very high vertical and temporal resolution. The system is also optimized to derive the vertical flux of horizontal momentum carried by high frequency gravity waves through the mesosphere and lower thermosphere. The radar has been used to study short term variability in the gravity wave momentum flux. Preliminary results on the gravity wave momentum flux variability in the MLT region for the 2012-2013 high latitude northern hemisphere winter season will be presented, together with a description of the system design.

De Wit, Rosmarie; Hibbins, Robert; Espy, Patrick

2013-04-01

60

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

SciTech Connect

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

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

1996-09-01

61

High-Level Radioactive Waste.  

ERIC Educational Resources Information Center

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

Hayden, Howard C.

1995-01-01

62

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

SciTech Connect

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

Jones, A.M.; Ingledew, M.M. (Univ. of Saskatchewan, Saskatoon (Canada))

1994-03-01

63

Internal gravity waves in the thermosphere during low and high solar activity: Simulation study  

NASA Astrophysics Data System (ADS)

Propagation of internal gravity waves (GWs) from the lower atmosphere into the upper thermosphere, and their dynamical and thermal effects have been studied under low and high solar activity approximated by the F10.7 parameter. It has been done by using a nonlinear spectral parameterization in systematic offline calculations with typical wind and temperature distributions from the HWM and MSISE-90 models, and with interactive simulations using the University College London Coupled Middle Atmosphere-Thermosphere-2 (CMAT2) general circulation model (GCM) under solstice conditions. The estimates have been performed for relatively slow harmonics with horizontal phase velocities less than 100 m s-1, which are not affected by back reflection and/or ducting. GW drag and wave-induced heating/cooling are shown to be smaller below ~170 km at high solar activity, and larger above. The maxima of GW momentum deposition occur much higher in the upper thermosphere, but their peaks are twice as weak, 120 vs 240 m s-1 d-1, in the winter hemisphere when the insolation is large. Instead of strong net cooling in the upper thermosphere, GWs produce a weak heating at high solar activity created by fast harmonics less affected by dissipation. Molecular diffusion increases with solar activity at fixed pressure levels, but seen in a Cartesian altitude grid it can show increasing and decreasing tendencies in the lower thermosphere with respect to low solar activity. Therefore, in pressure coordinates, in which most of GCMs operate, the influence of larger temperatures can be viewed as a competition between the enhanced dissipation and vertical expansion of the atmosphere.

Yi?it, Erdal; Medvedev, Alexander S.

2010-05-01

64

Internal gravity waves in the thermosphere during low and high solar activity: Simulation study  

NASA Astrophysics Data System (ADS)

Propagation of internal gravity waves (GWs) from the lower atmosphere into the upper thermosphere, and their dynamical and thermal effects have been studied under low and high solar activity approximated by the F10.7 parameter. It has been done by using a nonlinear spectral parameterization in systematic offline calculations with typical wind and temperature distributions from the HWM and MSISE-90 models, and with interactive simulations using the University College London Coupled Middle Atmosphere-Thermosphere-2 (CMAT2) general circulation model (GCM) under solstice conditions. The estimates have been performed for relatively slow harmonics with horizontal phase velocities less than 100 m s-1, which are not affected by reflection and/or ducting. GW drag and wave-induced heating/cooling are shown to be smaller below ˜170 km at high solar activity, and larger above. The maxima of GW momentum deposition occur much higher in the upper thermosphere, but their peaks are half as strong, 120 vs 240 m s-1 day-1 in the winter hemisphere when the insolation is large. Instead of strong net cooling in the upper thermosphere, GWs produce a weak heating at high solar activity created by fast harmonics less affected by dissipation. Molecular viscosity increases with solar activity at fixed pressure levels, but seen in Cartesian altitude grids it can either increase or decrease in the lower thermosphere, depending on the height. Therefore, in pressure coordinates, in which most GCMs operate, the influence of larger temperatures can be viewed as a competition between the enhanced dissipation and vertical expansion of the atmosphere.

Yi?it, Erdal; Medvedev, Alexander S.

2010-08-01

65

A gravity wave-critical level encounter observed in the atmosphere  

Microsoft Academic Search

The radar and balloon data of Gossard et al. (1970) for an event on August 6, 1969, are examined and calculations presented showing that the wavelike motions observed by the radar are Kelvin-Helmholtz instabilities; the layer of intense wind shear that surrounds the height of the radar returns is shown to be a critical layer for gravity waves themselves generated

John T. Merrill; John R. Grant

1979-01-01

66

Revealing the beneficial effect of protease supplementation to high gravity beer fermentations using "-omics" techniques  

PubMed Central

Background Addition of sugar syrups to the basic wort is a popular technique to achieve higher gravity in beer fermentations, but it results in dilution of the free amino nitrogen (FAN) content in the medium. The multicomponent protease enzyme Flavourzyme has beneficial effect on the brewer's yeast fermentation performance during high gravity fermentations as it increases the initial FAN value and results in higher FAN uptake, higher specific growth rate, higher ethanol yield and improved flavour profile. Results In the present study, transcriptome and metabolome analysis were used to elucidate the effect on the addition of the multicomponent protease enzyme Flavourzyme and its influence on the metabolism of the brewer's yeast strain Weihenstephan 34/70. The study underlines the importance of sufficient nitrogen availability during the course of beer fermentation. The applied metabolome and transcriptome analysis allowed mapping the effect of the wort sugar composition on the nitrogen uptake. Conclusion Both the transcriptome and the metabolome analysis revealed that there is a significantly higher impact of protease addition for maltose syrup supplemented fermentations, while addition of glucose syrup to increase the gravity in the wort resulted in increased glucose repression that lead to inhibition of amino acid uptake and hereby inhibited the effect of the protease addition.

2011-01-01

67

Frequencies of gravity-capillary waves on highly curved interfaces with edge constraints  

NASA Astrophysics Data System (ADS)

A recently developed technique to calculate the natural frequencies of gravity-capillary waves in a confined liquid mass with a possibly highly curved free surface is extended to the case where the contact line is pinned. The general technique is worked out in detail for the cases of rectangular and cylindrical containers of circular section, the cases for which experimental data are available. The results of the present method are in excellent agreement with all earlier experimental and theoretical data for the flat static interface case [Benjamin and Scott, 1979. Gravity-capillary waves with edge constraints. J. Fluid Mech. 92, 241-267; Graham-Eagle, 1983. A new method for calculating eigenvalues with applications to gravity-capillary waves with edge constraints. Math. Proc. Camb. Phil. Soc. 94, 553-564; Henderson and Miles, 1994. Surface-wave damping in a circular cylinder with a fixed contact line. J. Fluid Mech. 275, 285-299]. However, the present method is applicable even when the contact angle is not ?/2 and the static interface is curved. As a consequence we are able to work out the effects of a curved meniscus on the results of Cocciaro et al. [1993. Experimental investigation of capillary effects on surface gravity waves: non-wetting boundary conditions. J. Fluid Mech. 246, 43-66] where the measured contact angle was 62?. We find that the meniscus does indeed account, as suggested by Cocciaro et al., for the earlier discrepancy between theory and experiment of about 20 mHz and there is now excellent agreement between the two.

Shankar, P. N.

2007-06-01

68

Gravity waves in the middle atmosphere during the MaCWAVE winter campaign: evidence of mountain wave critical level encounters  

NASA Astrophysics Data System (ADS)

Falling sphere and balloon wind and temperature data from the MaCWAVE winter campaign, which was conducted in northern Scandinavia during January 2003, are analyzed to investigate gravity wave characteristics in the stratosphere and mesosphere. There were two stratospheric warming events occurring during the campaign, one having a maximum temperature perturbation at ~45 km during 17-19 January, and the other having a maximum perturbation at ~30 km during 24-27 January. The former was a major event, whereas the latter was a minor one. Both warmings were accompanied by upper mesospheric coolings, and during the second warming, the upper mesospheric cooling propagated downward. Falling sphere data from the two salvos on 24-25 January and 28 January were analyzed for gravity wave characteristics. Gravity wave perturbations maximized at ~45-50 km, with a secondary maximum at ~60 km during Salvo 1; for Salvo 2, wave activity was most pronounced at ~60 km and above.

Gravity wave horizontal propagation directions are estimated using the conventional hodographic analysis combined with the S-transform (a Gaussian wavelet analysis method). The results are compared with those from a Stokes analysis. They agree in general, though the former appears to provide better estimates for some cases, likely due to the capability of the S-transform to obtain robust estimates of wave amplitudes and phase differences between different fields.

For Salvo 1 at ~60 km and above, gravity waves propagated towards the southeast, whereas for Salvo 2 at similar altitudes, waves propagated predominantly towards the northwest or west. These waves were found not to be topographic waves. Gravity wave motions at ~45-50 km in Salvo 1 were more complicated, but they generally had large amplitudes, short vertical scales, and their hodographs revealed a northwest-southeast orientation. In addition, the ratios between wave amplitudes and intrinsic phase speeds generally displayed a marked peak at ~45-50 km and decreased sharply at ~50 km, where the background winds were very weak. These results suggest that these wave motions were most likely topographic waves approaching their critical levels. Waves were more nearly isotropic in the lower stratosphere.

Wang, L.; Fritts, D. C.; Williams, B. P.; Goldberg, R. A.; Schmidlin, F. J.; Blum, U.

2006-07-01

69

A concept for the estimation of high-degree gravity field models in a high performance computing environment  

NASA Astrophysics Data System (ADS)

The estimation of the global Earth's gravity field parametrized as a finite spherical harmonic series is computationally demanding. The computational effort depends on the one hand on the maximal resolution of the spherical harmonic expansion (i.e. the number of parameters to be estimated) and on the other hand on the number of observations (which might be several millions). All global high-resolution Earth's gravity field models currently available (above degree and order 360) were computed introducing approximations. These approximations significantly reduce the numerical complexity. For example, the prerequisites for the orthogonality of the spherical harmonic base functions, leading to a block diagonal system of normal equations, are often artificially introduced by working with equally distributed data along parallels with constant accuracy. In addition, these methods do not allow for a complex modeling of the observation errors, or the inclusion of redundant observations. The gravity fields are then derived from the block-diagonal normal equations. Within this contribution a concept for the rigorous estimation of high-degree gravity models above degree and order 2000 is presented. Iterative solvers implemented in a high performance computing environment using several thousands compute cores are used to derive the rigorous least-squares solution from millions of observations for more than 4 000 000 unknown parameters. A flexible design was implemented to process an arbitrary number of observation groups. For each of these observation groups a variance component can be estimated to derive a data adaptive weighting factor of each of these observation groups. For this reason a Monte Carlo based variance component estimation is integrated into the iterative solver. The combined solution is derived in a weighted joint estimation from all observation groups which might be preprocessed normal equations (e.g. from the dedicated gravity field missions like CHAMP, GRACE or GOCE) or observations like data sets of point-wise measured terrestrial gravity field information. The concept of the implemented solver is demonstrated. A small scale closed loop simulation serves as proof of concept.

Brockmann, Jan Martin; Roese-Koerner, Lutz; Schuh, Wolf-Dieter

2013-04-01

70

Acute and intermediate cardiovascular responses to zero gravity and to fractional gravity levels induced by head-down or head-up tilt.  

PubMed

Determination of early cardiovascular responses to simulated gravity levels between 0 and 1 G will add knowledge of cardiovascular responses to space flight. Cardiovascular responses to 6 hours in a -5 degrees head-down bedrest model of weightlessness (0 G) were compared to those in head-up tilts of +10 degrees, +20 degrees, and +42 degrees (1/6, 1/3, and 2/3 G, respectively). Six healthy young adult males experienced the four angles on separate days. Impedance cardiography was used to measure thoracic fluid index, cardiac output, stroke volume, and peak flow. Although much intersubject variation occurred, the mean thoracic fluid content at -5 degrees decreased during the first hour and remained decreased; 6-hour values were similar to +10 degrees and +20 degrees. Heart rate decreased the first 2 hours for all angles, then increased, converging at 3-4 hours, and reached control by hour 6. Stroke volume decreased for the first 3 hours at -5 degrees, +10 degrees, +20 degrees; values at all four angles converged at hour 3 and increased in unison thereafter. Cardiac output and peak aortic flow reflected the angle at start of tilt; values at all angles converged by the second hour, decreased through the third hour, and increased thereafter. Pulse pressure decreased for the first 3 hours for angles -5 degrees, +10 degrees, and +20 degrees, converged at the fourth hour, and returned to control. Peak flow at +42 degrees was constant for the first 3 hours and increased thereafter. Blood pressure decreased for the first 2 hours, although the greatest decrease occurred at -5 degrees and +42 degrees; thereafter, values at all angles increased in unison and converged at the fourth hour. Total peripheral resistance increased during the first hour at -5 degrees and +20 degrees and decreased from hour 3 to hours 5-6 at the +42 degrees angle. Cardiovascular values were related to tilt angle for the first 2 hours of tilt, but after hour 3 values at all four angles began to converge, suggesting that cardiovascular homeostatic mechanisms seek a common adapted state regardless of effective gravity level (tilt angle) up to 2/3 G. PMID:2355102

Lathers, C M; Diamandis, P H; Riddle, J M; Mukai, C; Elton, K F; Bungo, M W; Charles, J B

1990-06-01

71

Isostasy of the Moon from high-resolution gravity and topography data: Implication for its thermal history  

Microsoft Academic Search

The Lunar Prospector line-of-sight acceleration data after terrain correction have been inverted to the high-resolution Bouguer gravity anomalies of the lunar nearside. Lithospheric thicknesses of the early Moon were investigated by comparing the gravity anomalies of craters and impact basins of various dimensions. The lithosphere was already thick enough to support craters with diameters up to 300 km in the

T. Sugano; K. Heki

2004-01-01

72

Synchronous absolute EIT in three thoracic planes at different gravity levels  

NASA Astrophysics Data System (ADS)

The validity of absolute Electrical Impedance Tomography (a-EIT) for assessment of local lung volume has been investigated far less than the well evaluated ventilation monitoring by functional EIT (f-EIT). To achieve progress in a-EIT we investigated 10 healthy volunteers in an upright sitting position by using a-EIT at normal gravity (1 g), weightlessness (0 g) and approx. double gravity (1.8 g) during parabolic flight manoeuvres. Lung resistivity in three thoracic planes was determined by a-EIT using a multiple-plane synchronised Goe-MF II EIT system. Tomograms of resistivity at end-expiration in normal spontaneous breathing were reconstructed by a modified SIRT algorithm. Local lung resistivity was determined separately for both lungs. The respective resistivity values at 1 g and 1.8 g before and after weightlessness show an almost reversible behaviour along the sequence of gravity changes with a tendency to be lower after occurrence of weightlessness. The results reveal not only the expected varying resistivity of lung tissue in cranio-caudal direction but also a clear difference in these cranio-caudal stratifications of local lung volume between the left and right lung. The resolution and stability of absolute EIT seem to be valid and expressive for future investigations of unilateral lung volume under different physiological and pathological conditions.

Hahn, G.; Just, A.; Dittmar, J.; Fromm, K. H.; Quintel, M.

2013-04-01

73

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

SciTech Connect

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

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

1990-07-24

74

High-gravity as a research tool in studying the nature of structure formation in polymers  

NASA Astrophysics Data System (ADS)

This paper is concerned with the use of high-gravity as a means of enhancing and studying mechanism of gel formation which are weak in normal and microgravity conditions or exist under the disguise of free convection. The experimental set up specifically designed for this purpose allowed us to visualize the fields of the monomer conversion and the reaction mixture flows during gel synthesis on a centrifuge. The obtained data have been used to assess the role of the detected gravitational mechanisms and to determine the character of their interaction for different ways of reaction initiation.

Briskman, V.; Kostarev, K.; Shmyrov, A.

75

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

NASA Astrophysics Data System (ADS)

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

Fašková, Z.; Macák, M.; ?underlík, R.; Mikula, K.

2012-04-01

76

Histone modifying proteins Gcn5 and Hda1 affect flocculation in Saccharomyces cerevisiae during high-gravity fermentation.  

PubMed

The performance of yeast is often limited by the constantly changing environmental conditions present during high-gravity fermentation. Poor yeast performance contributes to incomplete and slow utilization of the main fermentable sugars which can lead to flavour problems in beer production. The expression of the FLO and MAL genes, which are important for the performance of yeast during industrial fermentations, is affected by complex proteins associated with Set1 (COMPASS) resulting in the induction of flocculation and improved maltose fermentation capacity during the early stages of high-gravity fermentation. In this study, we investigated a possible role for other histone modifying proteins. To this end, we tested a number of histone deacetylases (HDACs) and histone acetyltransferases and we report that flocculation is induced in absence of the histone deacetylase Hda1 or the histone acetyltransferase Gcn5 during high-gravity fermentation. The absence of Gcn5 protein also improved utilization of high concentrations of maltose. Deletion of SIR2 encoding the HDA of the silent informator regulator complex, did not affect flocculation under high-gravity fermentation conditions. Despite the obvious roles for Hda1 and Gcn5 in flocculation, this work indicates that COMPASS mediated silencing is the most important amongst the histone modifying components to control the expression of the FLO genes during high-gravity fermentation. PMID:20012864

Dietvorst, Judith; Brandt, Anders

2009-12-13

77

Three-dimensional transient simulation of Marangoni flow in a cylindrical enclosure under various gravity levels  

NASA Astrophysics Data System (ADS)

A numerical study is undertaken of the interaction between natural convection and Marangoni flow in a vertical cylindrical enclosure of aspect ratio 1, which has an adiabatic free lateral face and isothermal top and bottom walls. The 3D transient code uses a hybrid finite-difference scheme on a staggered grid with explicit time-steps, and an iterative pressure-velocity coupling. The flow patterns and isotherms are found to remain qualitatively unchanged in different gravity environments, and no significant disturbance of the axially symmetric flow mode is observed.

Marek, R.; Straub, J.

78

Gravity, Time, and Lagrangians  

ERIC Educational Resources Information Center

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

Huggins, Elisha

2010-01-01

79

High-density particulate gravity currents and their internal density stratifications  

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

80

Optimizing High Level Waste Disposal  

SciTech Connect

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

Dirk Gombert

2005-09-01

81

High Resolution Dynamics Limb Sounder observations of the gravity wave-driven elevated stratopause in 2006  

NASA Astrophysics Data System (ADS)

Temperature observations during January and February 2006 from the High Resolution Dynamics Limb Sounder (HIRDLS), the Microwave Limb Sounder (MLS), and the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) satellite instruments are compared to illustrate the vertical range over which version 6 HIRDLS temperatures are scientifically useful. In order to determine the quality of HIRDLS temperatures in the middle atmosphere, we compare the height and temperature of the HIRDLS stratopause with MLS and SABER before, during, and after the 2006 major stratospheric sudden warming. Results show that HIRDLS observes the elevated stratopause at 78 km two days later than MLS and five days after SABER. We compare the geographical temperature structure of these data sets at 0.01 hPa during this period. Though HIRDLS temperatures are consistently 5-10 K lower in the mesosphere, this is the first study to show that the horizontal temperature distribution is in good spatial and temporal agreement with MLS and SABER up to ˜80 km. Gravity wave momentum flux and planetary wave 1 amplitudes are derived from HIRDLS and shown to be in agreement with previous studies. We use HIRDLS to show a ˜30 K increase in stratopause temperature following enhanced gravity wave momentum flux in the lower mesosphere.

France, J. A.; Harvey, V. L.; Alexander, M. J.; Randall, C. E.; Gille, J. C.

2012-10-01

82

Exploring Quantum Gravity with Very-High-Energy Gamma-Ray Instruments - Prospects and Limitations  

SciTech Connect

Some models for quantum gravity (QG) violate Lorentz invariance and predict an energy dependence of the speed of light, leading to a dispersion of high-energy gamma-ray signals that travel over cosmological distances. Limits on the dispersion from short-duration substructures observed in gamma-rays emitted by gamma-ray bursts (GRBs) at cosmological distances have provided interesting bounds on Lorentz invariance violation (LIV). Recent observations of unprecedentedly fast flares in the very-high energy gamma-ray emission of the active galactic nuclei (AGNs) Mkn 501 in 2005 and PKS 2155-304 in 2006 resulted in the most constraining limits on LIV from light-travel observations, approaching the Planck mass scale, at which QG effects are assumed to become important. I review the current status of LIV searches using GRBs and AGN flare events, and discuss limitations of light-travel time analyses and prospects for future instruments in the gamma-ray domain.

Wagner, Robert [Max-Planck-Institut fuer Physik, D-80805 Muenchen (Germany)

2009-04-08

83

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

84

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

SciTech Connect

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

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

1987-12-31

85

Steric Sea-Level Change and its Impact on the Gravity Field caused by Global Climate Change  

NASA Astrophysics Data System (ADS)

It is sometimes assumed that steric sea-level variations do not produce a gravity signal as no net mass change, thus no change of ocean bottom pressure is associated with it. Analyzing the output of two CO2 emission scenarios over a period of 2000 years in terms of steric sea-level changes, we try to quantify the gravitational effect of steric sea-level variations. The first scenario, computed with version 2.6 of the Earth System Climate Model developed at the University of Victoria, Canada (UVic ESCM), is implemented with a linear CO2 increase of 1% of the initial concentration of 365 ppm and shows a globally averaged steric effect of 5.2 m after 2000 years. In the second scenario, computed with UVic ESCM version 2.7, the CO2 concentration increases quasi-exponentially to a level of 3011 ppm and is hold fixed afterwards. The corresponding globally averaged steric effect in the first 2000 years is 2.3 m. We show, due to the (vertical) redistribution of ocean water masses (expansion or contraction), the steric effect results also in a small change in the Earth’s gravity field compared to usually larger changes associated with net mass changes. Maximum effects for computation points located on the initial ocean surface can be found in scenario 1, with the effect on gravitational attraction and potential ranging from 0.0 to -0.7·10-5 m s-2 and -3·10-3 to 6·10-3 m2 s-2, respectively. As expected, the effect is not zero but negligible for practical applications.

Roedelsperger, Sabine; Kuhn, Michael; Makarynskyy, Oleg; Gerstenecker, Carl

2008-06-01

86

Critical level interaction of a gravity wave with background winds driven by a large-scale wave perturbation  

NASA Astrophysics Data System (ADS)

As part of the Maui-Mesosphere and Lower Thermosphere program, data from the Utah State University Mesospheric Temperature Mapper (MTM) and the University of Illinois Meteor Wind Radar (MWR) have been used to investigate wave-driven dynamical interactions in the upper mesosphere at low latitudes. On 29 June 2003, short-period (˜20 min) gravity waves (GWs) were imaged in the MTM in the near-infrared OH and O2 airglow emissions for most of the night from 0700 to 1500 UT. The GWs were observed to disappear rapidly in the O2 data (peak altitude: ˜94 km) around 1400 UT but remained evident in the lower altitudes OH data (˜87 km) for a further 30 min. Coincident background wind variations measured by the MWR suggest that the GW disappearance at the O2 layer was most probably caused by a critical level (CL) interaction. However, at the OH layer, the GW fading may also have been due to wave saturation and instabilities. During this period (1400-1500 UT), no significant change in OH and O2 rotational temperatures were measured by the MTM; however, the background winds centered on the airglow layers were observed to increase by ˜10 m/s. The background wind acceleration from the disappearing gravity waves estimated from the airglow observations was larger below the CL than at the CL, consistent with the wind variation observed by the MWR.

Ejiri, Mitsumu K.; Taylor, Michael J.; Nakamura, Takuji; Franke, Steven J.

2009-09-01

87

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

PubMed

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

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

2009-04-03

88

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

NASA Astrophysics Data System (ADS)

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

Hirt, Christian

2012-09-01

89

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

NASA Astrophysics Data System (ADS)

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

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

1994-05-01

90

Perception of body weight and body mass at twice earth-gravity acceleration levels.  

PubMed

On Earth, when standing on two feet, we experience particular patterns of force and pressure on the soles of our feet. As we lift one foot and balance on the other, little or no increase in force or pressure is perceived on the sole of the stance foot even though the contact forces of support on that foot have doubled. The failure to perceive this increase is actually an illusion resulting from the operation of spatial constancy mechanisms serving to preserve feelings of near constant force and pressure on the support surface(s) of the body. On Earth, body weight and body mass are perceived as remaining constant regardless as to whether we are standing on two feet or one and whether we are carrying large objects. In the high force phase(2 g acceleration) of parabolic flight, body weight is perceived as doubling, and a great increase in force is perceived on the soles of our feet if we are standing. When shifting balance from two feet to one, an increase in force of approximately 0.5 mg is felt on the sole of the stance foot. The actual increase in force is 1.0 mg but perceptual compensation is only being made for a 0.5 mg increase such as would be characteristic of shifting balance on Earth; accordingly an additional 0.5 mg (1.0-0.5 mg) residue is perceived. These findings indicate that body weight is dependent on the magnitude of the gravitoinertial forces acting on the body. Variations in the contact forces supporting the body due to passive or active locomotion of the body or to objects that are being carried are monitored and disregarded in computing apparent body weight. When stepping up and down from a low platform during the high force phases of parabolic flight, aberrant motion of the body and the aircraft is experienced. These illusory motions result because the doubling of body weight in a 2 g force background alters the normal relationship between patterns of alpha and gamma activation of antigravity muscles, muscle spindle activity, and the movements of the body. Accordingly, sensory-motor control and perceptual and postural stability on Earth are dependent on an active calibration to a 1 g background force level. PMID:6697150

Lackner, J R; Graybiel, A

1984-03-01

91

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

PubMed Central

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

2012-01-01

92

Gravity modulator and gravity-modulation reception  

US Patent & Trademark Office Database

An arrangement of gravity modulator and gravity-modulation receiver where photons or electromagnetic radiation is modulated electronically or mechanically to reach either a solid, liquid or mixed target possibly through or followed by a surrounding medium to produce gravity modulation in the target to effect gravity signaling which is received by a gravity-modulation receiver in or not in physical contact with the target. In the receiver, one or more piezo-electric transducer/s or quartz crystal/s receive the gravity modulation amplified for further signal processing. When not in physical contact with the target, the piezo-electric transducer/s is/are loaded with a resonator mass of natural resonant frequency either equal to, half, one third or one fifth of the frequency of the gravity modulator, the quartz crystal/s is/are gravity biased with a high-density metal piece along one direction of the oscillation mode of the crystal/s with natural resonant frequency similar to the resonator mass.

2013-08-27

93

Cell Sensitivity to Gravity  

NASA Astrophysics Data System (ADS)

Cultures of human lymphocytes exposed in microgravity to the mitogen concanavalin A showed less than 3 percent of the activation of ground controls. This result supports the hypothesis, based on simulations at low g and experiments at high g, that microgravity depresses whereas high gravity enhances cell proliferation rates. The effects of gravity are particularly strong in cells undergoing differentiation.

Cogoli, A.; Tschopp, A.; Fuchs-Bislin, P.

1984-07-01

94

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

SciTech Connect

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

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

2004-02-02

95

Ageing vessel configuration for continuous redox potential-controlled very-high-gravity fermentation.  

PubMed

The development of continuous very-high-gravity (VHG) fermentation is hindered by ineffective glucose uptake in order to result in zero discharge in the effluent stream. To overcome the problem, we proposed a continuous redox potential-controlled fermentation configuration, consisting of a Chemostat vessel connected with two ageing vessels installed in parallel, and the relevant design criteria are also specified. The Chemostat vessel is subjected to redox potential control to maintain yeast viability, and the ageing vessels are used to completely utilize glucose before discharging to next process unit. Two ageing vessels are scheduled alternatively, resulting in continuously-like operation. The size of ageing vessel is governed by the Chemostat size, dilution rate and filling time. The guideline to choose proper dilution rate is provided and the selection criterion of the proposed continuous configuration over batch fermentation is derived. The excess ethanol produced by the proposed continuous configuration over batch fermenter is quantified. As an illustration, a bio-ethanol plant is typically operated 8000 h per annum and the downtime between batches is 6h. Given that the fermenter size of 100 m(3) for both batch fermenter and Chemostat vessel, and glucose fed at 300 g/l, if the proposed continuous redox potential-controlled fermentation configuration (operated at 0.028 h(-1) and controlled at -50 mV) is selected, it will take 191 h for this configuration to outperform the batch counterpart, and the excess amount of ethanol being produced will be 1142 t. PMID:20875953

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

2010-09-28

96

The GRAVITY spectrometers: metrology laser blocking system  

NASA Astrophysics Data System (ADS)

A two stage blocking system is implemented in the GRAVITY science and the fringe tracking spectrometer optical design. The blocking system consists of a dichroic beam splitter and two long wave band-pass filters with the top level requirements of high transmission of the science light in the K-Band (1.95 - 2.45 ?m) region and high blocking power optical density (OD) >= 8 for each filter at the metrology laser wavelength of 1.908 ?m. The laser metrology blocking filters were identified as one critical optical component in the GRAVITY science and fringe tracker spectrometer design. During the Phase-C study of GRAVITY all the filters were procured and individually tested in terms of spectral response at K-band, transmission, blocking (OD) and reflection at the metrology laser wavelength. We present the measurements results of the full metrology blocking system in its final configuration as to be implemented in the GRAVITY spectrometers.

Araujo-Hauck, Constanza; Fischer, Sebastian; Gillessen, Stefan; Straubmeier, Christian; Wiest, Michael; Yazici, Senol; Wank, Imke; Eisenhauer, Frank; Perrin, Guy S.; Brandner, Wolfgang; Perraut, Karine; Amorim, António; Eckart, Andreas

2012-07-01

97

Gravity Field Changes due to Long-Term Sea Level Changes  

Microsoft Academic Search

Long-term sea level changes caused by climatic changes (e.g. global warming) will alter the system Earth. This includes the redistribution of ocean water masses due to the migration of cold fresh water from formerly ice-covered regions to the open oceans mainly caused by the deglaciation of polar ice caps. Consequently also a change in global ocean circulation patterns will occur.

O. Makarynskyy; M. Kuhn; W. E. Featherstone

2004-01-01

98

Fundamentals of gravity level dependent two-phase flow and heat transfer—A tutorial  

Microsoft Academic Search

Multiphase flow, the simultaneous flow of the different phases (states of matter) gas, liquid and solid, strongly depends on the level and direction of gravitation, since these influence the spatial distribution of the phases, having different densities. Many investigations concern behavior of liquid-solid flows (e.g. in mixing, crystal growing, or materials processing) or gas-solid flows (e.g. in cyclones or combustion

A. A. M. Delil

2001-01-01

99

Fundamentals of gravity level dependent two-phase flow and heat transfer-A tutorial  

Microsoft Academic Search

Multiphase flow, the simultaneous flow of the different phases (states of matter) gas, liquid and solid, strongly depends on the level and direction of gravitation, since these influence the spatial distribution of the phases, having different densities. Many investigations concern behavior of liquid-solid flows (e.g. in mixing, crystal growing, or materials processing) or gas-solid flows (e.g. in cyclones or combustion

A. A. M. Delil

2001-01-01

100

Pt-catalyzed ozonation of aqueous phenol solution using high-gravity rotating packed bed.  

PubMed

In this study, a high-gravity rotating packed bed (HGRPB or HG) was used as a catalytic ozonation (Cat-OZ) reactor to decompose phenol. The operation of HGRPB system was carried out in a semi-batch apparatus which combines two major parts, namely the rotating packed bed (RPB) and photo-reactor (PR). The high rotating speed of RPB can give a high volumetric gas-liquid mass transfer coefficient with one or two orders of magnitude higher than those in the conventional packed beds. The platinum-containing catalyst (Dash 220N, Pt/gamma-Al(2)O(3)) and activated alumina (gamma-Al(2)O(3)) were packed in the RPB respectively to adsorb molecular ozone and the target pollutant of phenol on the surface to catalyze the oxidation of phenol. An ultra violet (UV) lamp (applicable wavelength lambda=200-280 nm) was installed in the PR to enhance the self-decomposition of molecular ozone in water to form high reactive radical species. Different combinations of advanced oxidation processes (AOPs) with the HGRPB for the degradation of phenol were tested. These included high-gravity OZ (HG-OZ), HG catalytic OZ (HG-Cat-OZ), HG photolysis OZ (HG-UV-OZ) and HG-Cat-OZ with UV (HG-Cat-UV-OZ). The decomposition efficiency of total organic compound (eta(TOC)) of HG-UV-OZ with power of UV (P(UV)) of 16W is 54% at applied dosage of ozone per volume sample m(A,in)=1200 mg L(-1) (reaction time t=20 min), while that of HG-OZ without the UV irradiation is 24%. After 80 min oxidation (m(A,in)=4800 mg L(-1)), the eta(TOC) of HG-UV-OZ is as high as 94% compared to 82% of HG-OZ process. The values of eta(TOC) for HG-Cat-OZ process with m(S)=42 g are 56% and 87% at m(A,in)=1200 and 4800 mg L(-1), respectively. By increasing the catalyst mass to 77 g, the eta(TOC) for the HG-Cat-OZ process reaches 71% and 90% at m(A,in)=1200 and 4800 mg L(-1), respectively. The introduction of Pt/gamma-Al(2)O(3) as well as UV irradiation in the HG-OZ process can enhance the eta(TOC) of phenol significantly, while gamma-Al(2)O(3) exhibits no significant effect on eta(TOC). For the HG-Cat-UV-OZ process with m(S)=42 g, the values of eta(TOC) are 60% and 94% at m(A,in)=1200 and 4800 mg L(-1), respectively. Note that the decomposition of TOC via HG-UV-OZ is already vigorous. Thus, the enhancing effect of catalyst on eta(TOC) is minor. PMID:19395157

Chang, Chia-Chi; Chiu, Chun-Yu; Chang, Ching-Yuan; Chang, Chiung-Fen; Chen, Yi-Hung; Ji, Dar-Ren; Tseng, Jyi-Yeong; Yu, Yue-Hwa

2009-03-21

101

Tutorial on high-level synthesis  

Microsoft Academic Search

High-level synthesis takes an abstract behavioral specification of a digital system and finds a register-transfer level structure that realizes the given behavior. In this tutorial we will examine the high-level synthesis task, showing how it can be decomposed into a number of distinct but not independent subtasks. Then we will present the techniques that have been developed for solving those

Michael C. McFarland; Alice C. Parker; Raul Carnposano

1988-01-01

102

High resolution local Moho determination using gravity inversion: A case study in Sri Lanka  

NASA Astrophysics Data System (ADS)

The seismic data incorporated in global Moho models are sparse and therefore the interpolation of global Moho depths on a local area may give unrealistic results, especially in regions without adequate seismic information. Gravity inversion is a useful tool that can be used to determine Moho depths in the mentioned regions. This paper describes an interactive way of local Moho depth determination using the gravity inversion method constrained with available seismic data. Before applying inversion algorithms, the Bouguer gravity data is filtered in various stages that reduce the potential bias usually expected in Moho depth determination using gravity methods with constant density contrast assumption. A test area with reliable seismic data is used to validate the results of Moho computation, and subsequently the same computation procedure is applied to the Sri Lankan region. The results of the test area are in better agreement with seismically determined Moho depths than those obtained by global Moho models. In the Sri Lankan region, Moho determination reveals a fairly uniform thin crust of average thickness around 20 km. The overall result suggests that our gravity inversion method is robust and may be suitable for local Moho determination in virgin regions, especially those without sufficient seismic data.

Prasanna, H. M. I.; Chen, W.; ?z, H. B.

2013-09-01

103

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

PubMed

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

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

2002-09-26

104

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

PubMed

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

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

2012-02-17

105

Application of multistage continuous fermentation for production of fuel alcohol by very-high-gravity fermentation technology  

Microsoft Academic Search

  A fermentation system to test the merging of very-high-gravity (VHG) and multistage continuous culture fermentation (MCCF)\\u000a technologies was constructed and evaluated for fuel ethanol production. Simulated mashes ranging from 15% to 32% w\\/v glucose\\u000a were fermented by Saccharomyces cerevisiae and the dilution rates were adjusted for each glucose concentration to provide an effluent containing less than 0.3% w\\/v\\u000a glucose (greater

D P Bayrock; W Michael Ingledew

2001-01-01

106

Parallel Processing at the High School Level.  

ERIC Educational Resources Information Center

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

Sheary, Kathryn Anne

107

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

NASA Astrophysics Data System (ADS)

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

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

2013-01-01

108

Search for quantum gravity with IceCube and high energy atmospheric neutrinos  

NASA Astrophysics Data System (ADS)

IceCube is a 1 km3 neutrino telescope nearing completion in the South Pole Ice. Designed to detect astrophysical neutrinos from 100 GeV to about an EeV, it will contribute to the fields of high energy astrophysics, particle physics, and neutrino physics. This analysis looks at the flux of atmospheric neutrinos detected by IceCube while it operated in a partially-completed, 40-string configuration, from April 2008 to May 2009. From this data set, a sample of about 20,000 up-going atmospheric muon neutrino events with negligible background was extracted using Boosted Decision Trees. A discrete Fourier transform method was used to constrain a directional asymmetry in right ascension. Constraints on certain interaction coefficients from the Standard Model Extension were improved by three orders of magnitude, relative to prior experiments. The event sample was also used to unfold the atmospheric neutrino spectrum at its point of origin, and seasonal and systematic variations in the atmospheric muon neutrino flux were studied. A likelihood method was developed to constrain perturbations to the energy and zenith angle dependence of the atmospheric muon neutrino flux that could be due to Lorentz-violating oscillations or decoherence of neutrino flavor. Such deviations could be a signature of quantum gravity in the neutrino sector. The impact of systematic uncertainties in the neutrino flux and in the detector response on such a likelihood analysis were examined. Systematic uncertainties that need to be reduced in order to use a two-dimensional likelihood analysis to constrain phenomenological models for Lorentz or CPT violating neutrino oscillations were identified.

Huelsnitz, Warren

109

On the slumping of high Reynolds number gravity currents in two-dimensional and axisymmetric configurations  

Microsoft Academic Search

The behaviour of an inviscid gravity current of finite volume which is released from behind a lock and then propagates over a horizontal boundary is considered, for the elucidation of the initial ‘slumping’ phase during which the nose propagates with a constant velocity. The shallow-water two-layer model is used and the necessary front condition is provided, for comparisons, by four

M. Ungarish; T. Zemach

2005-01-01

110

Liouville gravity from Einstein gravity  

Microsoft Academic Search

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

2007-01-01

111

High-Level Application Framework for LCLS  

SciTech Connect

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

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

2008-04-22

112

Vesta Shape and Gravity  

NASA Video Gallery

This video from NASA's Dawn mission shows that the gravity field of Vesta closely matches the surface topography of the giant asteroid Vesta. The video shows shaded topography from Dawn's framing camera on the left, with troughs and craters visible, and color-contoured data from Dawn's gravity experiment on the right. Red shows the areas with a higher than average gravity field and blue-purple shows the areas where the field is weaker on average. The highest topography, on the rim of the Rheasilvia basin deep in the southern hemisphere, shows a particularly strong gravity field. The topography model is derived from framing camera images from Dawn's high-altitude mapping orbit (420 miles or 680 kilometers above the surface), and the gravity data come from the low-altitude mapping orbit (130 miles or 210 kilometers above the surface). Vesta takes approximately 5.34 hours to make a rotation.

Anthony Greicius

2012-04-24

113

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

PubMed

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

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

2012-02-22

114

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

USGS Publications Warehouse

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

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

2006-01-01

115

A Software Architecture for High Level Applications  

SciTech Connect

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

Shen,G.

2009-05-04

116

Turbulence and high-frequency variability in a deep gravity current outflow  

NASA Astrophysics Data System (ADS)

Intensive sampling of the deep Mediterranean outflow 70 km W of the Strait of Gibraltar reveals a strong, tidally modulated gravity current embedded with large-amplitude oscillations and energetic turbulence. The flow appears to be hydraulically controlled at a small topographic constriction, with turbulence and internal waves varying together and increasing dramatically downstream of the choke point. These data suggest that a significant fraction of energy dissipation, mixing, and entrainment stress in gravity currents may occur in localized regions controlled by time-varying flow interactions with fine-scale topography. These findings highlight the important role of processes that are not resolved by global climate models (GCMs), which do not contain tides or mixing due to fine-scale topographic interactions.

Nash, Jonathan D.; Peters, Hartmut; Kelly, Samuel M.; Pelegrí, Josep L.; Emelianov, Mikhail; Gasser, Marc

2012-09-01

117

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

Microsoft Academic Search

Most people take the constant presence of gravitys pull for granted. However, the Earth's gravitational strength actually varies from location to location. This variation occurs because mass, which influences an object's gravitational pull, is not evenly distributed within the planet. Changes in topography, such as glacial movement, an earthquake, or a rise in the ocean level, can subtly affect the

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

2000-01-01

118

Nonquantum Gravity  

Microsoft Academic Search

One of the great challenges for 21st century physics is to quantize gravity and generate a theory that will unify gravity\\u000a with the other three fundamental forces of nature. This paper takes the (heretical) point of view that gravity may be an inherently\\u000a classical, i.e., nonquantum, phenomenon and investigates the experimental consequences of such a conjecture. At present there\\u000a is

Stephen Boughn

2009-01-01

119

Box Calculus with High-Level Buffers  

Microsoft Academic Search

In this paper, we propose a high-level process algebra al- lowing to express the exchange of data values using both handshake and buffered communication. This allows a sim- ple and compositional expression of interprocess communi- cation; in particular the buffered one makes easy the repre- sentation of program variables, allowing a compact repre- sentation of large systems. The process terms

Cécile Bui Thanh; Hanna Klaudel; Franck Pommereau

120

Incentives for Partitioning High-Level Waste.  

National Technical Information Service (NTIS)

This document reports work to develop a general method for estimating the safety incentives for partitioning nuclear power economy wastes and to apply that method to a single waste type (accumulated high-level waste through the Year 2000 plus all tritium,...

H. C. Burkholder M. O. Cloninger D. A. Baker G. Jansen

1975-01-01

121

High Level Synthesis Tool for Systolic Designs,  

National Technical Information Service (NTIS)

Decomposer is a high level synthesis tool for automating the design of systolic systems. It is the newest entry in a tool set currently under development at Penn State. Decomposer takes as inputs a hierarchical description of the computation to be perform...

P. P. Hou R. M. Owens M. J. Irwin

1988-01-01

122

PAIRWISE BLENDING OF HIGH LEVEL WASTE (HLW)  

SciTech Connect

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

CERTA, P.J.

2006-02-22

123

The Department of Defense High Level Architecture  

Microsoft Academic Search

The High Level Architecture (HLA) provides the specification of a common technical architecture for use across all classes of simulations in the US Department of Defense. It provides the structural basis for simulation interoperability. The baseline definition of the HLA includes (1) the HLA Rules, (2) the HLA Interface Specification, and (3) the HLA Object Model Template. This paper describes

Judith S. Dahmann; Richard M. Fujimoto; Richard M. Weatherly

1997-01-01

124

Applying simulated evolution to high level synthesis  

Microsoft Academic Search

A general optimization algorithm known as simulated evolution (SE) is applied to the tasks of scheduling and allocation in high level synthesis. Basically, SE-based synthesis explores the design space by repeatedly ripping up parts of a design in a probabilistic manner and reconstructing them using application-specific heuristics that combine rapid design iterations and probabilistic hill climbing to achieve effective design

Tai A. Ly; Jack T. Mowchenko

1993-01-01

125

Triggering and High-Level Data Selection  

NASA Astrophysics Data System (ADS)

This document is part of Part 1 'Principles and Methods' of Subvolume B 'Detectors for Particles and Radiation' of Volume 21 'Elementary Particles' of Landolt-Börnstein - Group I 'Elementary Particles, Nuclei and Atoms'. It contains the Section '4.2 Triggering and High-Level Data Selection' of Chapter '4 Data Treatment and Analysis Methods' with the content:

Smith, W. H.

126

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

Microsoft Academic Search

By introducing ZrO2 (4Y) powder into the thermit, Al2O3\\/ZrO2 (4Y) composite ceramics of different composition and microstructures were prepared through combustion synthesis under high gravity, and the correlations of composition, microstructures and mechanical properties of composite ceramics were investigated. The results of XRD, SEM and EDS showed that Al2O3\\/33%ZrO2 (4Y) were composed of random-orientated rod-shaped colonies consisting of a triangular

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

2009-01-01

127

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

SciTech Connect

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

Smith, L.B.; Durney, T.

1991-01-01

128

Lunar gravity field recovery: GRAIL simulation studies  

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

129

Application of oscillation for efficiency improvement of continuous ethanol fermentation with Saccharomyces cerevisiae under very-high-gravity conditions.  

PubMed

Compared with steady state, oscillation in continuous very-high-gravity ethanol fermentation with Saccharomyces cerevisiae improved process productivity, which was thus introduced for the fermentation system composed of a tank fermentor followed by four-stage packed tubular bioreactors. When the very-high-gravity medium containing 280 g l(-1) glucose was fed at the dilution rate of 0.04 h(-1), the average ethanol of 15.8% (v/v) and residual glucose of 1.5 g l(-1) were achieved under the oscillatory state, with an average ethanol productivity of 2.14 g h(-1) l(-1). By contrast, only 14.8% (v/v) ethanol was achieved under the steady state at the same dilution rate, and the residual glucose was as high as 17.1 g l(-1), with an ethanol productivity of 2.00 g h(-1) l(-1), indicating a 7% improvement under the oscillatory state. When the fermentation system was operated under the steady state at the dilution rate of 0.027 h(-1) to extend the average fermentation time to 88 h from 59 h, the ethanol concentration increased slightly to 15.4% (v/v) and residual glucose decreased to 7.3 g l(-1), correspondingly, but the ethanol productivity was decreased drastically to 1.43 g h(-1) l(-1), indicating a 48% improvement under the oscillatory state at the dilution rate of 0.04 h(-1). PMID:19898843

Shen, Yu; Ge, X M; Bai, Feng Wu

2009-11-07

130

Loop quantum gravity as an effective theory  

NASA Astrophysics Data System (ADS)

As a canonical and generally covariant gauge theory, loop quantum gravity requires special techniques to derive effective actions or equations. If the proper constructions are taken into account, the theory, in spite of considerable ambiguities at the dynamical level, allows for a meaningful phenomenology to be developed, by which it becomes falsifiable. The traditional problems plaguing canonical quantum-gravity theories, such as the anomaly issue or the problem of time, can be overcome or are irrelevant at the effective level, resulting in consistent means of physical evaluations. This contribution presents aspects of canonical equations and related notions of (deformed) space-time structures and discusses implications in loop quantum gravity, such as signature change at high density from holonomy corrections, and falsifiability thanks to inversetriad corrections.

Bojowald, Martin

2012-09-01

131

High-level languages for SCADA  

SciTech Connect

Unlike business systems and even process control systems, SCADA systems incorporate a unique blend of real-time, rapid-time, soon-time, ''background,'' and even off-line processes. Depending on the computing power available, and the architecture chosen, the SCADA system builder may be able to use high-level languages to implement these processes. Advances in computer power and language efficiency have made it possible to minimize the use of assembly codes. A structured, modular, software design enables, the use of a mixture of various high-level languages, each with its own particular strengths. Experience gained over many years on projects executed by Rexnord Automation have ranged from SCADA systems based on the Digital Equipment Corp. PDP-11 computer family with software written in assembly code MACRO and a ''home-brew'' operating system, through SCADA systems based on the DEC VAX computer family with software written in ''C'' and running under the VMS system.

Shaw, T.

1986-09-01

132

High-Level Waste Melter Review  

SciTech Connect

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

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

2002-02-26

133

High-Level Waste Melter Study Report  

SciTech Connect

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

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

2001-07-13

134

High-Level Integration of Data Systems  

NASA Astrophysics Data System (ADS)

One of the key capabilities required for data systems of the future is the integration of high-level systems and services into their design. Future systems need to provide users with integrated access to distributed and diverse scientific data holdings, models, services, and tools in order to increase the science and educational return from the data. These new capabilities go well beyond the garden variety "get me data" types of services and should be accomplished as part of a broader structure which ties together existing systems at the same time as introducing new capabilities. Here, we present the high-level integration of systems and services as the necessary pieces to accomplish this as well as some lessons learned. and http://sd-www.jhuapl.edu/SPDML/index.php

Weiss, M.; Morrison, D.; Daley, R.; Immer, E.; Hashemian, M.; Fortner, B.; Jen, J.; Holder, R.

2005-12-01

135

Energy dissipation in shallow-water models for high-Re gravity currents  

NASA Astrophysics Data System (ADS)

The motion of a 2D gravity current, released from a lock in a horizontal channel is considered. Attention is focused on the energy transfers (between forms and fluids) and dissipation. The analysis uses the two-layer inviscid shallow-water (SW) formulation (with nose Froude numbers, Fr, given by Benjamin's and other formulas) and is backed by numerical Navier-Stokes results. We show that the current performs significant work on the ambient. In general, the increase of kinetic energy of the inviscid SW (or similar two-layer vertically-averaged) system cannot fully recover the decay of potential energy. This imbalance reproduces the classical dissipation predicted by Benjamin's steady-state analysis. We call this ``averaged flow dissipation''. This dissipation typically increases with the depth ratio of ambient to lock, and hence all deep SW currents (in particular the one-layer SW model predictions) with finite positive Fr are dissipative. However, the link between the ``averaged flow dissipation'' and the irreversible loss of energy in a real gravity current is missing. The implications on the validity of the SW predictions are discussed.

Ungarish, Marius

2006-11-01

136

Commissioning of the CMS High Level Trigger  

NASA Astrophysics Data System (ADS)

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

Agostino, L.; Bauer, G.; Beccati, B.; Behrens, U.; Berryhil, J.; Biery, K.; Bose, T.; Brett, A.; Branson, J.; Cano, E.; Cheung, H.; Ciganek, M.; Cittolin, S.; Coarasa, J. A.; Dahmes, B.; Deldicque, C.; Dusinberre, E.; Erhan, S.; Gigi, D.; Glege, F.; Gomez-Reino, R.; Gutleber, J.; Hatton, D.; Laurens, J.; Loizides, C.; Ma, F.; Meijers, F.; Meschi, E.; Meyer, A.; Mommsen, R. K.; Moser, R.; O'Dell, V.; Oh, A.; Orsini, L.; Patras, V.; Paus, C.; Petrucci, A.; Pieri, M.; Racz, A.; Sakulin, H.; Sani, M.; Schieferdecker, P.; Schwick, C.; Margaleff, J. F. S.; Shpakov, D.; Simon, S.; Sumorok, K.; Yoon, A. S.; Wittich, P.; Zanetti, M.

2009-10-01

137

Vertical fluctuation energy in United States high vertical resolution radiosonde data as an indicator of convective gravity wave sources  

NASA Astrophysics Data System (ADS)

Convectively generated internal gravity waves at extratropical latitudes are difficult to identify by climatological analysis of the temperature and horizontal wind fields from radiosonde profiles using traditional analysis methods. Here, we show that, by analyzing ascent rate profiles (we define a new variable, "vertical fluctuation energy (VE)"), we can identify convection sources in climatological analyses. Analysis of a 9-year time series (1998-2006) of United States high vertical resolution radiosonde data shows that VE maximizes in summer in midlatitudes within the troposphere (2-8.9 km), and peaks at local afternoon-early evening during the summer over most of the contiguous United States. Furthermore, the apparent dominant vertical wavelength based on Fourier analysis of the low-pass filtered ascent rate fluctuations also increase and decrease with VE, both on diurnal and seasonal timescales. VE in the lower stratosphere, however, does not show this same relationship to convection, but analysis of the vertical wavelength does show some of the features seen in tropospheric VE. Unlike midlatitude stations, VE within both the troposphere and the lower stratosphere over tropical western Pacific island stations is highly correlated with convective precipitation and inversely correlated with outgoing longwave radiation. We interpret this difference by using the 4-D Gravity Wave Regional or Global Ray Tracer ray-tracing model with a source spectrum representative of a convection source.

Gong, Jie; Geller, Marvin A.

2010-06-01

138

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)

2010-06-15

139

Increased expression of the yeast multidrug resistance ABC transporter Pdr18 leads to increased ethanol tolerance and ethanol production in high gravity alcoholic fermentation  

PubMed Central

Background The understanding of the molecular basis of yeast tolerance to ethanol may guide the design of rational strategies to increase process performance in industrial alcoholic fermentations. A set of 21 genes encoding multidrug transporters from the ATP-Binding Cassette (ABC) Superfamily and Major Facilitator Superfamily (MFS) in S. cerevisiae were scrutinized for a role in ethanol stress resistance. Results A yeast multidrug resistance ABC transporter encoded by the PDR18 gene, proposed to play a role in the incorporation of ergosterol in the yeast plasma membrane, was found to confer resistance to growth inhibitory concentrations of ethanol. PDR18 expression was seen to contribute to decreased 3?H-ethanol intracellular concentrations and decreased plasma membrane permeabilization of yeast cells challenged with inhibitory ethanol concentrations. Given the increased tolerance to ethanol of cells expressing PDR18, the final concentration of ethanol produced during high gravity alcoholic fermentation by yeast cells devoid of PDR18 was lower than the final ethanol concentration produced by the corresponding parental strain. Moreover, an engineered yeast strain in which the PDR18 promoter was replaced in the genome by the stronger PDR5 promoter, leading to increased PDR18 mRNA levels during alcoholic fermentation, was able to attain a 6?% higher ethanol concentration and a 17?% higher ethanol production yield than the parental strain. The improved fermentative performance of yeast cells over-expressing PDR18 was found to correlate with their increased ethanol tolerance and ability to restrain plasma membrane permeabilization induced throughout high gravity fermentation. Conclusions PDR18 gene over-expression increases yeast ethanol tolerance and fermentation performance leading to the production of highly inhibitory concentrations of ethanol. PDR18 overexpression in industrial yeast strains appears to be a promising approach to improve alcoholic fermentation performance for sustainable bio-ethanol production.

2012-01-01

140

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.

1988-09-10

141

Gravity model studies of Newberry Volcano, Oregon  

USGS Publications Warehouse

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. -Authors

Gettings, M. E.; Griscom, A.

1988-01-01

142

Time-variable gravity signal in Greenland revealed by high-low satellite-to-satellite tracking  

NASA Astrophysics Data System (ADS)

In the event of a termination of the Gravity Recovery and Climate Experiment (GRACE) mission before the launch of GRACE Follow-On (due for launch in 2017), high-low satellite-to-satellite tracking (hl-SST) will be the only dedicated observing system with global coverage available to measure the time-variable gravity field (TVG) on a monthly or even shorter time scale. Until recently, hl-SST TVG observations were of poor quality and hardly improved the performance of Satellite Laser Ranging observations. To date, they have been of only very limited usefulness to geophysical or environmental investigations. In this paper, we apply a thorough reprocessing strategy and a dedicated Kalman filter to Challenging Minisatellite Payload (CHAMP) data to demonstrate that it is possible to derive the very long-wavelength TVG features down to spatial scales of approximately 2000 km at the annual frequency and for multi-year trends. The results are validated against GRACE data and surface height changes from long-term GPS ground stations in Greenland. We find that the quality of the CHAMP solutions is sufficient to derive long-term trends and annual amplitudes of mass change over Greenland. We conclude that hl-SST is a viable source of information for TVG and can serve to some extent to bridge a possible gap between the end-of-life of GRACE and the availability of GRACE Follow-On.

Weigelt, M.; Dam, T.; Jäggi, A.; Prange, L.; Tourian, M. J.; Keller, W.; Sneeuw, N.

2013-07-01

143

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

NASA Astrophysics Data System (ADS)

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

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

2012-07-01

144

Searching for quantum gravity with high-energy atmospheric neutrinos and AMANDA-II  

NASA Astrophysics Data System (ADS)

The AMANDA-II detector, operating since 2000 in the deep ice at the geographic South Pole, has accumulated a large sample of atmospheric muon neutrinos in the 100 GeV to 10 TeV energy range. The zenith angle and energy distribution of these events can be used to search for various phenomenological signatures of quantum gravity in the neutrino sector, such as violation of Lorentz invariance (VLI) or quantum decoherence (QD). Analyzing a set of 5511 candidate neutrino events collected during 1387 days of livetime from 2000 to 2006, we find no evidence for such effects and set upper limits on VLI and QD parameters using a maximum likelihood method. Given the absence of new flavor-changing physics, we use the same methodology to determine the conventional atmospheric muon neutrino flux above 100 GeV.

Kelley, John Lawrence

2008-06-01

145

Seesaw modification of gravity  

NASA Astrophysics Data System (ADS)

We discuss a model in which the fundamental scale of gravity is restricted to 10-3 eV. An observable modification of gravity occurs simultaneously at the Hubble distance and at around 0.1 mm. These predictions can be tested both by the table-top experiments and by cosmological measurements. The model is formulated as a brane-world theory embedded in a space with two or more infinite-volume extra dimensions. Gravity on the brane reproduces the four-dimensional laws at observable distances but turns to the high-dimensional behavior at larger scales. To determine the crossover distance we smooth out the singularities in the Green’s functions by taking into account softening of the graviton propagator due to the high-dimensional operators that are suppressed by the fundamental scale. We find that irrespective of the precise nature of microscopic gravity the ultraviolet and infrared scales of gravity modification are rigidly correlated. This fixes the fundamental scale of gravity at 10-3 eV. The result persists for nonzero thickness branes.

Dvali, Gia; Gabadadze, Gregory; Hou, Xin-Rui; Sefusatti, Emiliano

2003-02-01

146

The effects of high level infrasound  

SciTech Connect

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

Johnson, D.L.

1980-02-01

147

Acceleration of Gravity 2  

NSDL National Science Digital Library

This lab is between a Level 2 and Level 3 inquiry activity in that it should be assigned after students understand acceleration but before they learn about the acceleration gravity. Because there are many sources of error when using a pendulum, students c

Horton, Michael

2009-05-30

148

Analytical predictions of shapes of laminar diffusion flames in microgravity and earth gravity  

Microsoft Academic Search

Flame shape is an important observed characteristic of flames that can be used to scale flame properties such as heat release rates and radiation. Flame shape is affected by fuel type, oxygen levels in the oxidiser, inverse burning and gravity. The objective of this study is to understand the effect of high oxygen concentrations, inverse burning, and gravity on the

S. S. Krishnan; J. M. Abshire; P. B. Sunderland; Z.-G. Yuan; J. P. Gore

2008-01-01

149

Technetium Chemistry in High-Level Waste  

SciTech Connect

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

Hess, Nancy J.

2006-06-01

150

High accuracy electronic material level sensor  

DOEpatents

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

McEwan, Thomas E. (Livermore, CA)

1997-01-01

151

High accuracy electronic material level sensor  

DOEpatents

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

McEwan, T.E.

1997-03-11

152

Extended Theories of Gravity  

NASA Astrophysics Data System (ADS)

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

Capozziello, Salvatore; de Laurentis, Mariafelicia

2011-12-01

153

Lunar gravity gradiometry and requirement analysis  

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

154

Born-Infeld-Horava gravity  

SciTech Connect

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

Guellue, Ibrahim; Sisman, Tahsin Cagri; Tekin, Bayram [Department of Physics, Middle East Technical University, 06531, Ankara (Turkey)

2010-05-15

155

Antimatter Gravity and Antihydrogen Production  

Microsoft Academic Search

Certain modern theories of gravity predict that antimatter will fall differently than matter in the Earth's gravitational field. However, no experimental tests of gravity on antimatter exist and all conclusions drawn from experiments on matter depend, at some level, on a specific model. We have proposed a direct measurement that would compare the gravitational acceleration of antiprotons to that of

Michael H. Holzscheiter; T. Goldman; Michael Martin Nieto

1995-01-01

156

Airway injury during high-level exercise.  

PubMed

Airway epithelial cells act as a physical barrier against environmental toxins and injury, and modulate inflammation and the immune response. As such, maintenance of their integrity is critical. Evidence is accumulating to suggest that exercise can cause injury to the airway epithelium. This seems the case particularly for competitive athletes performing high-level exercise, or when exercise takes place in extreme environmental conditions such as in cold dry air or in polluted air. Dehydration of the small airways and increased forces exerted on to the airway surface during severe hyperpnoea are thought to be key factors in determining the occurrence of injury of the airway epithelium. The injury-repair process of the airway epithelium may contribute to the development of the bronchial hyper-responsiveness that is documented in many elite athletes. PMID:22247295

Kippelen, Pascale; Anderson, Sandra D

2012-01-12

157

Umbra's High Level Architecture (HLA) Interface  

SciTech Connect

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

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

2002-04-01

158

National high-level waste systems analysis  

SciTech Connect

Previously, no mechanism existed that provided a systematic, interrelated view or national perspective of all high-level waste treatment and storage systems that the US Department of Energy manages. The impacts of budgetary constraints and repository availability on storage and treatment must be assessed against existing and pending negotiated milestones for their impact on the overall HLW system. This assessment can give DOE a complex-wide view of the availability of waste treatment and help project the time required to prepare HLW for disposal. Facilities, throughputs, schedules, and milestones were modeled to ascertain the treatment and storage systems resource requirements at the Hanford Site, Savannah River Site, Idaho National Engineering Laboratory, and West Valley Demonstration Project. The impacts of various treatment system availabilities on schedule and throughput were compared to repository readiness to determine the prudent application of resources. To assess the various impacts, the model was exercised against a number of plausible scenarios as discussed in this paper.

Kristofferson, K.; O`Holleran, T.P.

1996-05-01

159

Lunar Scout Two spacecraft gravity experiment  

Microsoft Academic Search

Measurement of the gravity field of the Moon has a high science priority because of its implications for the internal structure and thermal history of the Moon, and it has a high priority for future exploration activities because of the influence of lunar gravity on spacecraft navigation and orbit maintenance. The current state of knowledge in the lunar gravity field

Andrew F. Cheng

1993-01-01

160

Principal facts for about 16,000 gravity stations in the Nevada test site and vicinity  

NASA Astrophysics Data System (ADS)

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

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

161

New results from Nevada: A test of Newton's law using the BREN tower and a high density ground gravity survey.  

National Technical Information Service (NTIS)

We report new results from the LLNL test of Newton's law of gravity being conducted at the Nevada Test Site with a stable 465-m tower and a denser ground gravity survey than any used to date (823 locations within 4 km of the tower). Measurements of gravit...

J. Kammeraad P. Kasameyer O. Fackler D. Felske R. Harris

1990-01-01

162

? gravity: Steepness control  

NASA Astrophysics Data System (ADS)

We investigate a simple generalization of the metric exponential f(R) gravity theory that is cosmologically viable and compatible with solar system tests of gravity. We show that, as compared to other viable f(R) theories, its steep dependence on the Ricci scalar R facilitates agreement with structure constraints, opening the possibility of f(R) models with an equation-of-state parameter that could be differentiated from a cosmological constant (wde=-1) with future surveys at both background and perturbative levels.

O'Dwyer, Márcio; Jorás, Sérgio E.; Waga, Ioav

2013-09-01

163

Precision gravity monitoring of the Bulalo geothermal field, Philippines: independent checks and constraints on numerical simulation  

Microsoft Academic Search

Sixteen precision gravity surveys carried out since 1979 provide an additional constraint for numerical simulation of the Bulalo system. The gravity surveys were all run using the same LaCoste and Romberg gravity meter (D-33). Leveling surveys collected in conjunction with the gravity surveys used Wild N3 spirit levels. The leveling surveys were used to correct the gravity data for elevation

Gregg Nordquist; John Alfred P Protacio; Jorge A Acuña

2004-01-01

164

Massive hermitian gravity  

NASA Astrophysics Data System (ADS)

Einstein-Strauss Hermitian gravity was recently formulated as a gauge theory where the tangent group is taken to be the pseudo-unitary group instead of the orthogonal group. A Higgs mechanism for massive gravity was also formulated. We generalize this construction to obtain massive Hermitian gravity with the use of a complex Higgs multiplet. We show that both the graviton and antisymmetric tensor acquire the same mass. At the linearized level, the theory is ghost free around Minkowski background and describes a massive graviton with five degrees of freedom and an antisymmetric field with three degrees of of freedom. We determine the strong coupling scales for these degrees of freedom and argue that the potential nonlinear ghosts, if they exist, have to decouple from the gravitational degrees of freedom in strong coupling regime.

Chamseddine, Ali H.; Mukhanov, Viatcheslav

2012-08-01

165

Predicting gravity and sediment thickness in Afghanistan  

NASA Astrophysics Data System (ADS)

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

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

2013-02-01

166

Consistently high urine specific gravity in adolescent American football players and the impact of an acute drinking strategy.  

PubMed

The purpose of this study was to determine whether high-school football players showed risks of fluid deficits during two-a-day training (Part 1), and whether implementing a drinking strategy could acutely improve the markers of hydration (Part 2). In Part 1, pre-training urine specific gravity (USG) and pre- and post-training body weight were measured at the morning session for 5 consecutive days of two-a-day practices to monitor the hydration status of 13 varsity players. The mean pre-training body weight was consistently lower (mean decrease of 0.5 kg, p<0.05) following the first day of measurement. Pre-training USG values remained consistently high each day (range for daily means: 1.022+/-0.003 to 1.024+/-0.005). Part 2 consisted of assessing hydration status in 46 varsity and junior varsity players prior to morning training during two-a-day training before and following implementing a drinking strategy. In association with the strategy, mean body weight increased 0.5 kg (p<0.01) and mean USG decreased from 1.021 to 1.016 (p<0.01) following the drinking protocol. The slight decline in body weight and consistently high USG (Part 1) suggested that standard fluid replacement strategies were less than optimal for a majority of the players. Implementing a drinking strategy appeared to improve hydration status based on changes in body weight and USG (Part 2). PMID:16572377

Stover, E A; Zachwieja, J; Stofan, J; Murray, R; Horswill, C A

2006-04-01

167

DEFENSE HIGH LEVEL WASTE GLASS DEGRADATION  

SciTech Connect

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

W. Ebert

2001-09-20

168

Inflation and gravity models  

NASA Astrophysics Data System (ADS)

The thesis is devoted to a number of fundamental issues at the intersection of particle physics and cosmology. In particular, we invent one of the first models of the brane inflationary scenario in string theory, the so-called D-brane inflation. In this picture, the role of the inflation field is played by the brane-anti-brane separation. Branes are slowly attracted toward each other. During this slow motion, the potential energy of their tension causes the four-dimensional space to inflate. Inflation ends by the brane collision and annihilation, which reheats the Universe. Thus, in our picture inflation acquires a novel geometric meaning as seen from high-dimensional string theory. Another subject investigated in the thesis is the large distance modification of gravity, which is motivated by the observed mysterious accelerated expansion of the Universe. We study different aspects of the two possible approaches leading to modified gravity. One is Dvali-Gabadadze-Porrati (DGP) model, in which gravity gets modified at large distances because of the presence of extra dimensions. We study some cosmological and gravitational aspects of this theory. We also discuss an alternative picture in which gravity is modified directly in four dimensions due to the addition of some lower dimensional curvature invariants to the Einstein's action. We show that such local modifications of gravity are not viable, as they always propagate additional degrees of freedom that are excluded either by experiments or by the consistency requirements of the theory.

Solganik, Sviatoslav

169

Gravity's rainbow  

Microsoft Academic Search

A nonmathematical description of the basic ideas behind some recently proposed experiments for testing Einstein's theory of gravitation is given. Mention is made of gravity wave detectors, the possibility of detecting the gamma radiation or radio waves emitted from exploding black holes, the use of a circular cavity waveguide with superconducting walls to detect induced drag caused by a rapidly

P. C. W. Davies

1978-01-01

170

GOCE Quick-Look Gravity Field Analysis  

Microsoft Academic Search

The goal of the GOCE satellite mission (steady state Gravity field and Ocean Circulation Explorer), which will be launched by ESA (European Space Agency) in spring 2008, is to observe the Earth's gravity field with high resolution and global coverage. It is based on a sensor fusion concept which will combine SST (satellite-to- satellite tracking) measurements and SGG (satellite gravity

M. Wermuth; R. Pail; R. Mayrhofer

2007-01-01

171

Massive gravity  

NASA Astrophysics Data System (ADS)

The concept of mass has been central in many areas of physics. Gravitation is not an exception, and it has been one of the long-standing questions whether the graviton, a spin-2 particle that mediates gravity, can have a non-vanishing mass or not. This question is relevant from not only theoretical but also phenomenological viewpoints, since a nonzero graviton mass may lead to late-time acceleration of the universe and thus may be considered as an alternative to dark energy. In 2010, de Rham, Gabadadze and Tolley proposed the first example of a fully nonlinear massive gravity theory and showed that the so called Boulware-Deser ghost, which had been one of the major obstacles against a stable nonlinear theory of massive gravity since 1972, can be removed by construction. Since then, nonlinear massive gravity has been attracting significant interest among physicists and cosmologists. The nonlinear theory of massive gravity provides a theoretical framework in which properties of the remaining five physical degrees of freedom of massive gravity can be studied. As always with any low-energy effective theories, one of the first tasks would be to identify good and bad backgrounds. Depending on the choice of backgrounds, some of the five degrees of freedom may become strongly coupled, may exhibit instantaneous propagation, or may lead to ghost/gradient instabilities. A related subject is to seek interesting solutions such as those relevant for astrophysical objects and those describing self-accelerating cosmology. Those solutions will allow us to study phenomenological and cosmological implications of the theory. Yet another important task would be to seek a possible (partial) UV completion that can be applied beyond the regime of validity of the low-energy effective theory that we currently know of. We invited articles to cover those important subjects in massive gravity. Given the recent rapid developments in the field, however, it must be noted that this focus issue should be best considered as a snapshot. We still hope that the collection of articles provides readers with guidance to the research at the frontier and ideally expedites further progress in the field. Shinji MukohyamaGuest Editor

Mukohyama, Shinji

2013-09-01

172

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

PubMed

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

Tesio, L; Lanzi, D; Detrembleur, C

1998-03-01

173

Residual geoid and free-air gravity over the indian offshore from ers-1 high resolution altimeter data  

Microsoft Academic Search

In this study, ERS-1 altimeter data over the Indian offshore have been processed for deriving marine geoid and gravity. Processing\\u000a of altimeter data involves corrections for various atmospheric and oceanographic effects, stacking and averaging of repeat\\u000a passes, cross-over correction, removal of deeper earth and bathymetric effects, spectral analyses and conversion of geoid\\u000a into free-air gravity anomaly. Methods for generation of

R. BHATTACHARYYAAND; T. J. Majumdar

2006-01-01

174

A high-quality global gravity field model from CHAMP GPS tracking data and accelerometry (EIGEN1S)  

Microsoft Academic Search

Using three months of GPS satellite-to-satellite tracking and accelerometer data of the CHAMP satellite mission, a new long-wavelength global gravity field model, called EIGEN-1S, has been prepared in a joint German-French effort. The solution is derived solely from analysis of satellite orbit perturbations, i.e. independent of oceanic and continental surface gravity data. EIGEN-1S results in a geoid with an approximation

Christoph Reigber; Georges Balmino; Peter Schwintzer; Richard Biancale; Albert Bode; Jean-Michel Lemoine; Rolf König; Sylvain Loyer; Hans Neumayer; Jean-Charles Marty; Franz Barthelmes; Felix Perosanz; Shen Yuan Zhu

2002-01-01

175

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

PubMed

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

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

2006-04-15

176

Gravity changes, soil moisture and data assimilation  

NASA Astrophysics Data System (ADS)

Remote sensing holds promise for near-surface soil moisture and snow mapping, but current techniques do not directly resolve the deeper soil moisture or groundwater. The benefits that would arise from improved monitoring of variations in terrestrial water storage are numerous. The year 2002 saw the launch of NASA's Gravity Recovery And Climate Experiment (GRACE) satellites, which are mapping the Earth's gravity field at such a high level of precision that we expect to be able to infer changes in terrestrial water storage (soil moisture, groundwater, snow, ice, lake, river and vegetation). The project described here has three distinct yet inter-linked components that all leverage off the same ground-based monitoring and land surface modelling framework. These components are: (i) field validation of a relationship between soil moisture and changes in the Earth's gravity field, from ground- and satellite-based measurements of changes in gravity; (ii) development of a modelling framework for the assimilation of gravity data to constrain land surface model predictions of soil moisture content (such a framework enables the downscaling and disaggregation of low spatial (500 km) and temporal (monthly) resolution measurements of gravity change to finer spatial and temporal resolutions); and (iii) further refining the downscaling and disaggregation of space-borne gravity measurements by making use of other remotely sensed information, such as the higher spatial (25 km) and temporal (daily) resolution remotely sensed near-surface soil moisture measurements from the Advanced Microwave Scanning Radiometer (AMSR) instruments on Aqua and ADEOS II. The important field work required by this project will be in the Murrumbidgee Catchment, Australia, where an extensive soil moisture monitoring program by the University of Melbourne is already in place. We will further enhance the current monitoring network by the addition of groundwater wells and additional soil moisture sites. Ground-based gravity measurements will also be made on a monthly basis at each monitoring site. There will be two levels of modelling and monitoring; regional across the entire Murrumbidgee Catchment (100,000 km2), and local across a small sub-catchment (150 km2).

Walker, J.; Grayson, R.; Rodell, M.; Ellet, K.

2003-04-01

177

A Study on the Drive at Center of Gravity (DCG) Feed Principle and Its Application for Development of High Performance Machine Tool Systems  

Microsoft Academic Search

For high performance machining, it is essential to minimize the vibration of a machine tool, which is incurred due to the instantaneous acceleration\\/deceleration. To minimize this vibration, it is fundamentally ideal to apply the driving force at the most shock-insensitive position of the moving structure: the center of gravity. Aiming at developing unparalleled high-performance machine tool systems, the effectiveness of

K. Hiramoto; A. Hansel; S. Ding; K. Yamazaki

2005-01-01

178

Commissioning of the CMS High Level Trigger  

Microsoft Academic Search

The CMS experiment will collect data from the proton-proton collisions delivered by the Large Hadron Collider (LHC) at a centre-of-mass energy up to 14 TeV. The CMS trigger system is designed to cope with unprecedented luminosities and LHC bunch-crossing rates up to 40 MHz. The unique CMS trigger architecture only employs two trigger levels. The Level-1 trigger is implemented using

Lorenzo Agostino; Gerry Bauer; Barbara Beccati; Ulf Behrens; Jeffrey Berryhil; Kurt Biery; Tulika Bose; Angela Brett; James Branson; Eric Cano; Harry Cheung; Marek Ciganek; Sergio Cittolin; Jose Antonio Coarasa; Bryan Dahmes; Christian Deldicque; Elizabeth Dusinberre; Samim Erhan; Dominique Gigi; Frank Glege; Robert Gomez-Reino; Johannes Gutleber; Derek Hatton; Jean-Francois Laurens; Constantin Loizides; Frank Ma; Frans Meijers; Emilio Meschi; Andreas Meyer; Remigius K Mommsen; Roland Moser; Vivian O'Dell; Alexander Oh; Luciano Orsini; Vaios Patras; Christoph Paus; Andrea Petrucci; Marco Pieri; Attila Racz; Hannes Sakulin; Matteo Sani; P. Schieferdecker; Christoph Schwick; Josep Francesc Serrano Margaleff; Dennis Shpakov; Sean Simon; Konstanty Sumorok; Andre Sungho Yoon; Peter Wittich; Marco Zanetti

2009-01-01

179

High Frequency/High Magnitude Middle Miocene Sea Level Cycles Recorded in Carbonate Bank Margins in the Maldives  

NASA Astrophysics Data System (ADS)

The beginning of the middle Miocene marks an abrupt change from aggradation to intense progradation of the Maldives carbonate platform. 2D seismic data from the Maldives, equatorial Indian Ocean, shows that isolated carbonate bank margins of middle Miocene age are composed of five prograding sequences. Based on the interpretation of stratal patterns along separate transects, a qualitative relative sea level curve for the middle Miocene was constructed. Each sequence is interpreted to represent a complete sea level cycle. Each cycle begins with a relative sea level fall recorded in downstepping geometries, followed by flooding and a subsequent highstand. The duration of each cycle are estimated to be about 1 Ma or less, and the amplitude of the falls as high as 100 m. The subsequent sea level rises appear to be of high magnitude also, almost always restoring to the previous position. The terminal middle Miocene sequence in the Maldives contains massive gravity-flow deposits at the toe of slope interpreted as a result of a significant sea level drop. Located in the tectonically stable setting and removed from pulses of siliciclastic sediments, the Maldives middle Miocene relative sea level record must contain a strong eustatic component. Oxygen isotope record in the middle Miocene shows a stepwise increase in heavy isotopes implying growth of continental ice. Growth of the East Antarctica Ice Sheet and probably initiation of the West Antarctica Ice Sheet occurred in the middle Miocene. These records point to a eustatic sea level fall in the middle Miocene but do not show high frequency/high magnitude cycles as recorded in the Maldives margins. The Maldives record demonstrates a transition from a dominantly greenhouse world with small frequency and magnitudes cycles to the ice-house world with high frequency/high magnitude cycles.

Belopolsky, A. V.; Belopolsky, A. V.; Droxler, A. W.

2001-05-01

180

Analytic expansions of luni-solar gravity perturbations along rotating axes for trajectory optimization: Part 1: The dynamic system  

Microsoft Academic Search

An analytic form of the accelerations due to the luni-solar perturbations resolved along the rotating Euler-Hill frame is devised by using the expansion method. The addition of higher order terms to the main gravity gradient term linear in the spacecraft radial distance, carried out to the third order, provides a very high level of accuracy in accounting for the gravity

Jean A. Kéchichian

2011-01-01

181

Global grids of gravity anomalies and vertical gravity gradients at 10 km altitude from GOCE gradient data 2009-2011 and polar gravity.  

NASA Astrophysics Data System (ADS)

The GOCE satellite measures gravity gradients which are filtered and transformed to gradients into an Earth-referenced frame by the GOCE High Level processing Facility. More than 80000000 data with 6 components are available from the period 2009-2011. IAG Arctic gravity was used north of 83 deg., while data at the Antarctic was not used due to bureaucratic restrictions by the data-holders. Subsets of the data have been used to produce gridded values at 10 km altitude of gravity anomalies and vertical gravity gradients in 20 deg. x 20 deg. blocks with 10' spacing. Various combinations and densities of data were used to obtain values in areas with known gravity anomalies. The (marginally) best choice was vertical gravity gradients selected with an approximately 0.125 deg spacing. Using Least-Squares Collocation, error-estimates were computed and compared to the difference between the GOCE-grids and grids derived from EGM2008 to deg. 512. In general a good agreement was found, however with some inconsistencies in certain areas. The computation time on a usual server with 24 processors was typically 100 minutes for a block with generally 40000 GOCE vertical gradients as input. The computations will be updated with new Wiener-filtered data in the near future.

Tscherning, Carl Christian; Arabelos, Dimitrios; Reguzzoni, Mirko

2013-04-01

182

Gravity quantized: Loop quantum gravity with a scalar field  

SciTech Connect

...''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)

2010-11-15

183

Cohomological gravity  

SciTech Connect

In the present work, the authors construct a theory of cohomological gravity in arbitrary dimensions based upon a local vector supersymmetry algebra. The observables in this theory are polynomial, but generally non-local operators, and have a natural interpretation in terms of a universal bundle for gravity. As such, their correlation functions correspond to cohomology classes on moduli spaces of Riemannian connections. In this uniformization approach, different moduli spaces are obtained by introducing curvature singularities on codimension two submanifolds via a puncture operator. This puncture operator is constructed from a naturally occurring differential form of co-degree two in the theory, and the authors are led to speculate on connections between this continuum quantum field theory, and the discrete Regge calculus. 16 refs.

Birmingham, D. (CERN, Geneva (Switzerland)); Rakowski, M. (Johannes-Gutenberg Universitaet, Mainz (Germany))

1993-07-01

184

Soft Scheduling in High Level Synthesis  

Microsoft Academic Search

In this paper, we establish a theoretical framework for a newconcept of scheduling called soft scheduling. In contraststo the traditional schedulers referred as hard schedulers, softschedulers make soft decisions at a time, or decisions thatcan be adjusted later. Soft scheduling has a potential to alleviatethe phase coupling problem that has plagued traditionalhigh level synthesis (HLS), HLS for deep submicrondesign and

Jianwen Zhu; Daniel D. Gajski Cecs

1998-01-01

185

3-D modeling and simulation of crystal growth of GE?.?? Si?.?? under the influence of various gravity levels, G-jitter and rotating magnetic field using traveling solvent method  

Microsoft Academic Search

A three-dimensional numerical simulation was conducted to study the effect of a rotating magnetic (RMF) field on the fluid flow, heat transfer and mass transfer in the presence of various gravity levels by utilizing the traveling solvent method (TSM). The presence of the RMF suppressed the buoyancy convection in the GE?.?? Si?.?? solution zone in order to get homogeneity with

Mehdi Mohammadi Shemirani

2008-01-01

186

VHDL as Input for High-Level Synthesis  

Microsoft Academic Search

High-level synthesis is defined, and the feasibility of high-level synthesis from a behavioral, sequential description in VHDL (VHSIC hardware description language) is examined. It is seen that in some cases the semantics and descriptive power of the language create difficulties for high-level synthesis, and in other cases the high-level synthesis framework used imposes limitations. Restrictions in the form of rules

Raul Camposano; L. F. Saunders; R. M. Tabet

1991-01-01

187

Screening mechanisms in modified gravity  

NASA Astrophysics Data System (ADS)

The ubiquitous role of light scalar fields in modified gravity models necessitates the introduction of screening mechanisms whereby gravitation in the solar system can be described by the General Theory of Relativity to an extremely precise level. On larger scales, the laws of gravity can be modified with various phenomelogical consequences. We review the status of the three main mechanisms when a single scalar field modifies gravity. We emphasize the qualitative and quantitative differences between the models subject to the chameleon and the Damour–Polyakov mechanisms on the one hand, and the Vainshtein mechanism on the other hand.

Brax, Philippe

2013-11-01

188

Airborne Gravity Gradiometry Resolves a Full Range of Gravity Frequencies  

NASA Astrophysics Data System (ADS)

Airborne Full Tensor Gradiometry (Air\\-FTGR) was flown at high altitude coincident with Airborne Gravity (AG) flown in 2003 in West Arnhem Land, Australia. A preliminary analysis of two data sets indicates that the Air\\-FTGR system has the capability of resolving intermediate to long wavelengths features that may be associated with relatively deeper geological structures. A comparison of frequency filtered slices and power spectral density (PSD) for both data sets using the short (> 5 km), intermediate (10 km) and long (20 km) wavelengths reveals that high altitude Air\\-FTGR data show greater response in high frequency anomalies than a conventional Airborne Gravity and matches well with the AG even at the longest wavelengths anomalies. The effect of line spacing and target resolution was examined between the two data sets. Reprocessed gradient and AG data at 2, 4 and 6 km line spacing suggest that Air\\-FTGR could be effectively flown at a comparatively wider line spacing to resolve similar targets the AG would resolve with tighter line spacing. Introduction Airborne Full Tensor Gradiometry (Air\\-FTGR) data have been available to the mining industry since 2002 and their use for geologic applications is well established. However, Air\\-FTGR data has been mostly considered and used in mapping and delineation of near surface geological targets. This is due to the fact that gravity gradiometer measurements are well suited to capture the high frequency signal associated with near\\-surface targets ( Li, 2001). This is possible because the gradiometer signal strength falls off with the cube of the distance to the target. Nonetheless, in recent years there has been an increasing demand from the mining, oil, and gas industry in utilizing Full Tensor Gravity Gradiometer as a mapping tool for both regional and prospect level surveys. Air\\-FTGR as a Regional Mapping Tool Several, relatively low altitude surveys have been successfully flown in Brazil, Canada and Australia mostly targeting large, regional\\- scale crustal structures as well as regional mapping of both lithology and regolith. Air\\-FTGR mapping is especially effective in areas of thick lateritic and/or clay cover where other geophysical methods such as airborne magnetics or electromagnetics become less effective. For instance, an Air\\-FTGR survey was successfully flown in Brazil in the Province of Minas Gerais, where several crustal\\-scale structures associated with iron oxide mineralization were identified ( Mataragio et. al., 2006). In addition, in 2006 Air\\-FTGR had good success in the regional mapping of structures associated with Iron Oxide Copper Gold (IOCG) and uranium mineralization in the Wernecke Mountains in the Yukon, and Northwest Territories, Canada. On the basis of these successful surveys, Bell Geospace has initiated a number of high altitude test surveys aiming at evaluating the performance of the Air\\-FTGR system in capturing low frequency signal that may be associated with regional\\-scale, deeper structures. One of the test surveys was conducted in December of 2006 in Australia, where the performance of Air\\-FTGR and the conventional Airborne Gravity were evaluated. Airborne gravity is currently considered well suited for capturing low frequency signal.

Mataragio, J.; Brewster, J.; Mims, J.

2007-12-01

189

46 CFR 182.530 - Bilge high level alarms.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Bilge high level alarms. 182.530 Section 182.530...Ballast Systems § 182.530 Bilge high level alarms. (a) On a vessel of at...operating station to indicate a high water level in each of the following normally...

2011-10-01

190

46 CFR 182.530 - Bilge high level alarms.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Bilge high level alarms. 182.530 Section 182.530...Ballast Systems § 182.530 Bilge high level alarms. (a) On a vessel of at...operating station to indicate a high water level in each of the following normally...

2012-10-01

191

46 CFR 153.409 - High level alarms.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false High level alarms. 153.409 Section 153.409...Cargo Gauging Systems § 153.409 High level alarms. When Table 1 refers to this...cargo's containment system must have a high level alarm: (a) That gives an...

2012-10-01

192

46 CFR 153.409 - High level alarms.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false High level alarms. 153.409 Section 153.409...Cargo Gauging Systems § 153.409 High level alarms. When Table 1 refers to this...cargo's containment system must have a high level alarm: (a) That gives an...

2011-10-01

193

40 CFR 227.30 - High-level radioactive waste.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false High-level radioactive waste. 227.30 Section 227.30 Protection... Definitions § 227.30 High-level radioactive waste. High-level radioactive waste means the aqueous waste resulting...

2013-07-01

194

Oil gravity segregation in the Monterey formation, California  

SciTech Connect

The Monterey Formation is a fractured siliceous shale that is the principal reservoir and source rock for oil fields in the Santa Maria basin and the western Santa Barbara Channel. Monterey crudes in producing offshore fields are high-sulfur oils that range from 10[degrees] to 35[degrees] API. The oils in Monterey fractured reservoirs display a systematic increase in API gravity with increasing height above the oil-water contact. The rate of change in API gravity with depth in Monterey oil fields generally ranges from 0.5[degrees] to 1.2[degrees] API/100 ft. The oil-water contact usually occurs at an oil gravity of 10[degrees] API (the gravity at which the density of the oil and the water is equal). The maximum API gravity in a Monterey oil field is related to the level of thermal exposure experienced by the formation in the adjacent depocenter. Monterey oils are sourced by high-sulfur kerogens that generate heavy oils at low levels of thermal exposure, but generate progressively higher gravity oils at higher levels of thermal maturity. Comparison of the maximum API gravity found in 33 Monterey-sourced oil fields with the maximum temperature experienced by the Monterey Formation within three miles of the field (the most likely migration distance) suggests that a temperature of 260[degrees]F (127[degrees]C) is required to generate 20[degrees] API oil, and a temperature of 330[degrees]F (166[degrees]C) is required to generate 30[degrees] API oil.

Hornafius, J.S. (Mobil Exploration and Producing, Bakersfield, CA (United States))

1994-04-01

195

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

PubMed

The effects of cross-coupled stimuli on the semicircular canals are shown to be influenced by the position of the subject's head with respect to gravity and the axis of rotation, but not by the subject's head position relative to the trunk. Seventeen healthy subjects made head yaw movements out of the horizontal plane while lying on a horizontal platform (MIT short radius centrifuge) rotating at 23 rpm about an earth-vertical axis. The subjects reported the magnitude and duration of the illusory pitch or roll sensations elicited by the cross-coupled rotational stimuli acting on the semicircular canals. The results suggest an influence of head position relative to gravity. The magnitude estimation is higher and the sensation decays more slowly when the head's final position is toward nose-up (gravity in the subject's head x-z-plane) compared to when the head is turned toward the side (gravity in the subject's head y-z-plane). The results are discussed with respect to artificial gravity in space and the possible role of pre-adaptation to cross-coupled angular accelerations on earth. PMID:14501104

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

196

ICONDENSATION: Unifying Low-Level and High-Level Tracking in a Stochastic Framework  

Microsoft Academic Search

. Tracking research has diverged into two camps; low-level approaches which are typically fast and robust but provide little fine-scale information, and high-level approaches which track complex deformations in high-dimensional spaces but must trade off speed against robustness. Real-time high-level systems perform poorly in clutter and initialisation for most high-level systems is either performed manually or by a separate module.

Michael Isard; Andrew Blake

1998-01-01

197

Eustatic control of gravity tectonics: Concept, mechanism and limits  

SciTech Connect

Gravity tectonics over a ductile decollement characterizes deformation of the Albian to Recent section in the West African margin, from Gabon to Angola. Largely studied during the past 20 years as a prolific petroleum play, it is now well known that three mains factors will control gravity driven deformation: the ductile layer, the slope as a response to the crustal activity and the overlying sedimentary loading. For the West African passive margin, the slope effect at the first glance can be considered as constant and gravity driven deformation as a result of salt layer distribution (in time and space) and sedimentary loading. If previous papers have already shown that the type and distribution of the deposits control the development of the classical structural domains : updip extensional to downdip contractional, this study will focused on the factor which control the sedimentary loading. Based on several natural examples combining seismic stratigraphy, sequential stratigraphy and structural studies and also analogical modelling, it is demonstrated that: (1) as sediment distribution and then sedimentary loading is controlled by relative sea level changes, thus sea level changes can be directly related to gravity driven deformation : large sea level fall will provide an important increase of clastics supply which will enhanced gravity gliding. On the contrary, relative sea level high will stop the deformation because of the decreasing amount of detritics and their homogeneous distribution. (2) the salt downdip withdrawal during extension will enhance the eustatic effect. (3) episodic crustal activity, materialized by westward tilting of the margin will interfere on this mechanism.

Raillard, S.; Allix, P.; Guerin, G.; Lecanu, H. (Elf Aquitaine Production, Pau (France)) (and others)

1996-01-01

198

Period analysis at high noise level  

NASA Astrophysics Data System (ADS)

Analytical expressions are derived for the variances of three types of periodograms due to normal-distributed noise present in the data: the conventional Fourier spectrum, the method of Warner and Robinson (1972), and Jurkevich's method (1971). The equivalence of the Jurkevich method and that of Warner and Robinson is proved. The optimum phase cell number of the Warner-Robinson method is given; this number depends on the data length, signal form, and noise level. Results are illustrated by the analysis of two typical forms of light curves: an eclipsing type light curve and an RRa curve.

Kovacs, G.

1980-05-01

199

Self-assembled, nanostructured polypyrrole films grown in a high-gravity environment.  

PubMed

A simple, novel method of synthesizing self-assembled, nanostructured conducting polymer films has been developed. Applying an increased centrifugal force on the electrodes during the electrochemical deposition process yields high surface area, micro- or nanostructured polymer films. Scanning electron microscopy showed that as the applied g-force increased, the polymers progressed from having smooth, "cauliflower" morphologies, to intermediate microstructured surfaces, to finally dense nanostructured surfaces with pore sizes as small as 50 nm. Cyclic voltammetry revealed that films grown at higher centrifugal accelerations (higher than 500g) exhibited less degradation after electrochemical cycling and more capacitive behavior. PMID:22300451

Chang, Jean H; de Leon, Christian R Aleman; Hunter, Ian W

2012-02-29

200

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

NASA Astrophysics Data System (ADS)

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

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

2003-01-01

201

Advanced high-temperature ultracentrifuge apparatus for mega-gravity materials science  

NASA Astrophysics Data System (ADS)

An ultracentrifuge apparatus, which can generate an ultra-strong gravitational field even >1 000 000 (1 million) G (1 G=9.8 m/s2) over a wide temperature range up to >500 °C with high stability control, was developed for new materials science research. The system consists of an air turbine motor with ceramic ball bearings and dumper section, a sample rotor with an outer diameter of up to 160 mm, a vacuum chamber, and a heating system. The nonbored rotor and the double-structural dumper bushing are used to raise the maximum rotational speed and to improve the stability. The samples can be heated by radiant heat. A maximum rotational speed of 190 000 rpm using a 70 mm diam rotor was recorded despite a short time where the maximum gravitational field was >1 2000 000 G. Long and high-temperature ultracentrifuge experiments using 70 and 80 mm diam rotors made of titanium alloy with rotational speeds of up to 170 000 rpm even at temperatures of over 200 °C for 100 h with ripples of <0.05% and <1°, respectively, were successfully performed, where the maximum gravitational field of the sample was >1 000 000 G. The potential energy and sample volume were increased by factors of >2 and >4, respectively, compared with those in the Kumamoto University study [T. Mashimo, S. Okazaki, and S. Tashiro, Rev. Sci. Instrum. 67, 3170 (1996)].

Mashimo, Tsutomu; Huang, Xinsheng; Osakabe, Toyotaka; Ono, Masao; Nishihara, Masamichi; Ihara, Hirotaka; Sueyoshi, Masanori; Shibasaki, Koji; Shibasaki, Shiro; Mori, Nobuo

2003-01-01

202

Mesosphere-stratosphere-troposphere radar observations of characteristics of lower atmospheric high-frequency gravity waves passing through the tropical easterly jet  

Microsoft Academic Search

In this study, we have examined the characteristics of high-frequency gravity waves (5–50 min periodicity) over a tropical region using the mesosphere-stratosphere-troposphere (MST) radar installed at Gadanki (13.5°N, 79.2°E), India. The MST radar (53 MHz) was operated continuously for ?15.5 h during 1700–0840 LT on 2–3 June 2005. During this period, a strong unstable wind shear region existed above the

T. K. Ramkumar; K. Niranjan kumar; Sanjay K. Mehta

2010-01-01

203

Rapid and enhanced production of ethanol in very high gravity (VHG) sugar fermentation by Saccharomyces cerevisiae: Role of finger millet ( Eleusine coracana L.) flour  

Microsoft Academic Search

The effect of the supplementation of finger millet (Eleusine coracana L.) flour (4–6%, w\\/v) in the production of ethanol by yeasts in high gravity sugar (30–40%, w\\/v) containing yeast extract-peptone-malt extract medium was investigated. It was found that the finger millet flour not only reduced the fermentation time (from 5 to 3 days) but also enhanced the ethanol concentration from

L. V. A. Reddy; O. V. S. Reddy

2006-01-01

204

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)

2012-01-20

205

Marine gravity anomaly from Geosat and ERS 1 satellite altimetry  

NASA Astrophysics Data System (ADS)

Closely spaced satellite altimeter profiles collected during the Geosat Geodetic Mission (~6km) and the ERS 1 Geodetic Phase (8 km) are easily converted to grids of vertical gravity gradient and gravity anomaly. The long-wavelength radial orbit error is suppressed below the noise level of the altimeter by taking the along-track derivative of each profile. Ascending and descending slope profiles are then interpolated onto separate uniform grids. These four grids are combined to form comparable grids of east and north vertical deflection using an iteration scheme that interpolates data gaps with minimum curvature. The vertical gravity gradient is calculated directly from the derivatives of the vertical deflection grids, while Fourier analysis is required to construct gravity anomalies from the two vertical deflection grids. These techniques are applied to a combination of high-density data from the dense mapping phases of Geosat and ERS 1 along with lower-density but higher-accuracy profiles from their repeat orbit phases. A comparison with shipboard gravity data shows the accuracy of the satellite-derived gravity anomaly is about 4-7 mGal for random ship tracks. The accuracy improves to 3 mGal when the ship track follows a Geosat Exact Repeat Mission track line. These data provide the first view of the ocean floor structures in many remote areas of the Earth. Some applications include inertial navigation, prediction of seafloor depth, planning shipboard surveys, plate tectonics, isostasy of volcanoes and spreading ridges, and petroleum exploration.

Sandwell, David T.; Smith, Walter H. F.

1997-05-01

206

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

PubMed

Short-radius centrifugation offers a promising and affordable countermeasure to the adverse effects of prolonged weightlessness. However, head movements made in a fast rotating environment elicit Coriolis effects, which seriously compromise sensory and motor processes. We found that participants can adapt to these Coriolis effects when exposed intermittently to high rotation rates and, at the same time, can maintain their perceptual-motor coordination in stationary environments. In this paper, we explore the role of inter-sensory conflict in this adaptation process. Different measures (vertical nystagmus, illusory body tilt, motion sickness) react differently to visual-vestibular conflict and adapt differently. In particular, proprioceptive-vestibular conflict sufficed to adapt subjective parameters and the time constant of nystagmus decay, while retinal slip was required for VOR gain adaptation. A simple correlation between the strength of intersensory conflict and the efficacy of adaptation fails to explain the data. Implications of these findings, which differ from existing data for low rotation rates, are discussed. PMID:14501103

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

207

Real-time monitoring of high-gravity corn mash fermentation using in situ raman spectroscopy.  

PubMed

In situ Raman spectroscopy was employed for real-time monitoring of simultaneous saccharification and fermentation (SSF) of corn mash by an industrial strain of Saccharomyces cerevisiae. An accurate univariate calibration model for ethanol was developed based on the very strong 883?cm(-1) C-C stretching band. Multivariate partial least squares (PLS) calibration models for total starch, dextrins, maltotriose, maltose, glucose, and ethanol were developed using data from eight batch fermentations and validated using predictions for a separate batch. The starch, ethanol, and dextrins models showed significant prediction improvement when the calibration data were divided into separate high- and low-concentration sets. Collinearity between the ethanol and starch models was avoided by excluding regions containing strong ethanol peaks from the starch model and, conversely, excluding regions containing strong saccharide peaks from the ethanol model. The two-set calibration models for starch (R(2) ?=?0.998, percent error?=?2.5%) and ethanol (R(2) ?=?0.999, percent error?=?2.1%) provide more accurate predictions than any previously published spectroscopic models. Glucose, maltose, and maltotriose are modeled to accuracy comparable to previous work on less complex fermentation processes. Our results demonstrate that Raman spectroscopy is capable of real time in situ monitoring of a complex industrial biomass fermentation. To our knowledge, this is the first PLS-based chemometric modeling of corn mash fermentation under typical industrial conditions, and the first Raman-based monitoring of a fermentation process with glucose, oligosaccharides and polysaccharides present. PMID:23334886

Gray, Steven R; Peretti, Steven W; Lamb, H Henry

2013-02-07

208

The high-level synthesis of digital systems  

Microsoft Academic Search

High-level synthesis systems start with an abstract behavioral specification of a digital system and find a register-transfer level structure that realizes the given behavior. The various tasks involved in developing a register-transfer level structure from an algorithmic level specification are described. In particular, it is shown how the high-level synthesis task can be decomposed into a number of distinct but

M. C. McFarland; A. C. Parker; R. Camposano

1990-01-01

209

Analysis and interpretation of high-resolution topography and gravity of Ishtar Terra, Venus  

NASA Astrophysics Data System (ADS)

The apparent depth of compensation (ADC) of the topography of Venus, determined on a global scale using the Airy isostasy model, shows that the topography specified by the spherical harmonics of degree lower than 10 is compensated at depths greater than 150 km, that of degree higher than about 35 is compensated at a constant depth of about 35 km, and the compensation depths of the harmonics of degree 10-35 shoal as the harmonic degree increases. Based on these characteristics of the globally determined ADC, three different maps of the topography and gravitational potential of the Greater Ishtar Terra are derived using the harmonics of degree 1-75 (LW), 10-75 (IW), and 30-75 (SW), respectively. The LW maps of the topography and potential do not correlate well, but the IW and SW maps show good correlation, emphasizing that the long-wavelength components of the gravitational potential over the Ishtar Terra have contributions from sources broader than the Terra. The energy of the gravitational potential of the topography is about an order of magnitude greater than that of the observed potential, indicating that the topography is strongly compensated. The ADC of the topography is estimated by both spectral and space domain analysis. In the spectral domain, three independent procedures, the energy spectrum, the statistical method, and the wavelength-dependent method, are employed. The first two yield a mean ADC value for the entire spectrum, whereas the last one calculates the ADC for different wavelengths. The ADC decreases as the longer-wavelength components are excluded. The mean ADC values determined for the LW, IW, and SW maps by the energy spectrum method are 115, 65, and 40 km, respectively. Those calculated through the statistical method are 85, 55, and 34 km, respectively. These values reflect the upper and lower limits, because the energy spectrum method overestimates and the statistical method underestimates the ADC. The wavelength-dependent method shows that the ADCs of the wavelengths 500-1350 km are similar for all the maps but those of the longer wavelengths significantly differ among the maps. The mean ADC values also differ from the ADC of local topographic features. For example, the ADC of Maxwell Montes is about 55 km in both the LW and IW maps. In the space domain, the ADC is determined for Pratt and Airy isostasy models through fitting a linear and a quadratic function to the geoid height versus topography data, respectively. The ADC values determined show good agreement with the above-mentioned values. In addition, the relationship between the high-resolution topography and the line-of-sight acceleration residuals of the western Ishtar Terra specified by wavelengths of 300-500 km suggests that the high-resolution topography is compensated at a depth of about 25 km. We also determine the lateral density perturbations inside a surface layer so that together with the topography of the Greater Ishtar Terra they give rise to the observed gravitational potential over the Terra. Three layer thicknesses of 50, 100, and 200 km are examined. The resulting density perturbations are too large to be interpreted in terms of lateral temperature variations alone. This suggests lateral variations in the rock type; the crust beneath the mountain belts may contain considerable amounts of low-density material.

Arkani-Hamed, Jafar

210

Fermilab Tevatron high level rf accelerating systems  

SciTech Connect

Eight tuned rf cavities have been installed and operated in the F0 straight section of the Tevatron. Their mechanical placement along the beam line enables them to be operated for colliding beams as two independent groups of four cavities, group 1-4 accelerating antiprotons and group 5-8 accelerating protons. The only difference is that the spacing between cavities 4 and 5 was increased to stay clear of the F0 colliding point. The cavities can easily be rephased by switching cables in a low-level distribution system (fan-out) so that the full accelerating capability of all eight cavities can be used during fixed target operations. Likewise, the cables from capacitive probes on each cavity gap can be switched to proper lengths and summed in a fan-back system to give an rf signal representing the amplitude and phase as ''seen by the beam,'' separately for protons and antiprotons. Such signals have been used to phase lock the Tevatron to the Main Ring for synchronous transfer.

Kerns, Q.; Kerns, C.; Miller, H.; Tawser, S.; Reid, J.; Webber, R.; Wildman, D.

1985-06-01

211

Crystalline Order in High Landau Levels  

NASA Astrophysics Data System (ADS)

We numerically study electrons confined to a higher Landau level (e.g., N=2), by exact diagonalization. The use of periodic boundary conditions allows the clear detection of various broken symmetry electron crystal states, at filling factors not close to 1/2 (e.g., 1/4). These states appear to be the ``bubble'' phases predicted by Shklovskii et al. The broken symmetry is signaled by a striking quasi-degeneracy of the ground state, where the quasi-degenerate set of quantum numbers forms a 2D superlattice of Bragg vectors that characterizes the crystalline state (number of electrons per unit cell, shape, etc.), and also by quasi-divergent response functions. Variation of the pbc cell shape to optimize the quasi-degeneracy allows the intrinsically-preferred crystal structure to be found. These results are also consistent with recent experiments of Eisenstein et al. where a reentrant ? = 4 quantum Hall plateau was seen near near ?=4+1/4, suggesting a pinned crystal phase.

Haldane, F. D. M.; Rezayi, E. H.; Yang, Kun

2000-03-01

212

Progress in high-level exploratory vision  

NASA Astrophysics Data System (ADS)

We have been exploring the hypothesis that vision is an explanatory process, in which causal and functional reasoning about potential motion plays an intimate role in mediating the activity of low-level visual processes. In particular, we have explored two of the consequences of this view for the construction of purposeful vision systems: Causal and design knowledge can be used to (1) drive focus of attention, and (2) choose between ambiguous image interpretations. An important result of visual understanding is an explanation of the scene's causal structure: How action is originated, constrained, and prevented, and what will happen in the immediate future. In everyday visual experience, most action takes the form of motion, and most causal analysis takes the form of dynamical analysis. This is even true of static scenes, where much of a scene's interest lies in how possible motions are arrested. This paper describes our progress in developing domain theories and visual processes for the understanding of various kinds of structured scenes, including structures built out of children's constructive toys and simple mechanical devices.

Brand, Matthew

1993-08-01

213

Superconducting gravity gradiometer for sensitive gravity measurements. I. Theory  

SciTech Connect

Because of the equivalence principle, a global measurement is necessary to distinguish gravity from acceleration of the reference frame. A gravity gradiometer is therefore an essential instrument needed for precision tests of gravity laws and for applications in gravity survey and inertial navigation. Superconductivity and SQUID (superconducting quantum interference device) technology can be used to obtain a gravity gradiometer with very high sensitivity and stability. A superconducting gravity gradiometer has been developed for a null test of the gravitational inverse-square law and space-borne geodesy. Here we present a complete theoretical model of this instrument. Starting from dynamical equations for the device, we derive transfer functions, a common mode rejection characteristic, and an error model of the superconducting instrument. Since a gradiometer must detect a very weak differential gravity signal in the midst of large platform accelerations and other environmental disturbances, the scale factor and common mode rejection stability of the instrument are extremely important in addition to its immunity to temperature and electromagnetic fluctuations. We show how flux quantization, the Meissner effect, and properties of liquid helium can be utilized to meet these challenges.

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

1987-06-15

214

Superconducting gravity gradiometer for sensitive gravity measurements. I. Theory  

NASA Astrophysics Data System (ADS)

Because of the equivalence principle, a global measurement is necessary to distinguish gravity from acceleration of the reference frame. A gravity gradiometer is therefore an essential instrument needed for precision tests of gravity laws and for applications in gravity survey and inertial navigation. Superconductivity and SQUID (superconducting quantum interference device) technology can be used to obtain a gravity gradiometer with very high sensitivity and stability. A superconducting gravity gradiometer has been developed for a null test of the gravitational inverse-square law and space-borne geodesy. Here we present a complete theoretical model of this instrument. Starting from dynamical equations for the device, we derive transfer functions, a common mode rejection characteristic, and an error model of the superconducting instrument. Since a gradiometer must detect a very weak differential gravity signal in the midst of large platform accelerations and other environmental disturbances, the scale factor and common mode rejection stability of the instrument are extremely important in addition to its immunity to temperature and electromagnetic fluctuations. We show how flux quantization, the Meissner effect, and properties of liquid helium can be utilized to meet these challenges.

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

1987-06-01

215

Changes in water levels and storage in the High Plains Aquifer, predevelopment to 2009  

USGS Publications Warehouse

The High Plains aquifer underlies 111.8 million acres (175,000 square miles) in parts of eight States - Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming. The area overlying the High Plains aquifer is one of the primary agricultural regions in the Nation. Water-level declines began in parts of the High Plains aquifer soon after the onset of substantial irrigation with groundwater from the aquifer (about 1950 and termed "predevelopment" in this fact sheet). By 1980, water levels in the High Plains aquifer in parts of Texas, Oklahoma, and southwestern Kansas had declined more than 100 feet (ft) (Luckey and others, 1981). In 1987, in response to declining water levels, Congress directed the U.S. Geological Survey (USGS), in collaboration with numerous Federal, State, and local water-resources entities, to assess and track water-level changes in the aquifer. This fact sheet summarizes changes in water levels and drainable water in storage in the High Plains aquifer from predevelopment to 2009. Drainable water in storage is the fraction of water in the aquifer that will drain by gravity and can be withdrawn by wells. The remaining water in the aquifer is held to the aquifer material by capillary forces and generally cannot be withdrawn by wells. Drainable water in storage is termed "water in storage" in this report. A companion USGS report presents more detailed and technical information about water-level and storage changes in the High Plains aquifer during this period (McGuire, 2011).

McGuire, V.L.

2011-01-01

216

Model studies of time-dependent ducting for high-frequency gravity waves and associated airglow responses in the upper atmosphere  

NASA Astrophysics Data System (ADS)

This doctoral dissertation has mainly concentrated on modeling studies of shorter period acoustic-gravity waves propagating in the upper atmosphere. Several cases have been investigated in the literature, which are focusing on the propagation characteristics of highfrequency gravity wave packets. The dissertation consists of five main divisions of which each has its own significance to be addressed, and these five chapters are also bridged in order with each other to present a theme about gravity wave ducting dynamics, energetics, and airglows. The first chapter is served as an introduction of the general topic about atmospheric acoustic-gravity waves. Some of the historical backgrounds are provided as an interesting refreshment and also as a motivation reasoning this scientific research for decades. A new 2-D, time-dependent, and nonlinear model is introduced in the second chapter (the AGE-TIP model, acronymically named atmospheric gravity waves for the Earth plus tides and planetary waves). The model is developed during this entire doctoral study and has carried out almost all research results in this dissertation. The third chapter is a model application for shorter period gravity waves ducted in a thermally stratified atmosphere. In spite of mean winds the thermal ducting occurs because ducted waves are fairly common occurrences in airglow observations. One-dimensional Fourier analysis is applied to identify the ducted wave modes that reside within multiple thermal ducts. Besides, the vertical energy flux and the wave kinetic energy density are derived as wave diagnostic variables to better understand the time-resolved vertical transport of wave energy in the presence of multiple thermal ductings. The fourth chapter is also a model application for shorter period gravity waves, but it instead addresses the propagation of high-frequency gravity waves in the presence of mean background wind shears. The wind structure acts as a significant directional filter to the wave spectra and hence causes noticeable azimuthal variations at higher altitudes. In addition to the spectral analysis applied previously the wave action has been used to interpret the energy coupling between the waves and the mean flow among some atmospheric regions, where the waves are suspected to extract energy from the mean flow at some altitudes and release it to other altitudes. The fifth chapter is a concrete and substantial step connecting theoretical studies and realistic observations through nonlinearly coupling wave dynamic model with airglow chemical reactions. Simulated O (1S) (557.7 nm) airglow images are provided so that they can be compared with observational airglow images. These simulated airglow brightness variations response accordingly with minor species density fluctuations, which are due to propagating and ducting nonlinear gravity waves within related airglow layers. The thermal and wind structures plus the seasonal and geographical variabilities could significantly influence the observed airglow images. By control modeling studies the simulations can be used to collate with concurrent observed data, so that the incoherencies among them could be very useful to discover unknown physical processes behind the observed wave scenes.

Yu, Yonghui

217

High-level design and synthesis of a resource scheduler  

Microsoft Academic Search

Given the increasing complexity of current embedded systems, hardware design is being pushed to a higher level of abstraction, with High-Level Synthesis tools enabling hardware synthesis from untimed C++. Still, HLS technology does not provide a clear methodology to derive both hardware and software implementations from a single high-level code. This paper describes the design, implementation and evaluation of a

Joao Paulo Pizani Flor; Tiago Rogerio Muck; Antonio Augusto Frohlich

2011-01-01

218

Toward high-spatial resolution gravity surveying of the mid-ocean ridges with autonomous underwater vehicles  

Microsoft Academic Search

The shallow ocean crust of the mid-ocean ridge (MOR) is a critical environment where important chemical and biological exchanges occur. Resolving the 3-D structure of the subsurface environment beneath MOR crests at spatial scales ranging from 1-1000 meters remains a continuing challenge in marine geophysics. Previous submerged gravity surveys have employed manned, remotely operated, or towed submersibles - to date,

James C. Kinsey; Maurice A. Tivey; Dana R. Yoerger

2008-01-01

219

Vertical fluctuation energy in United States high vertical resolution radiosonde data as an indicator of convective gravity wave sources  

Microsoft Academic Search

Convectively generated internal gravity waves at extratropical latitudes are difficult to identify by climatological analysis of the temperature and horizontal wind fields from radiosonde profiles using traditional analysis methods. Here, we show that, by analyzing ascent rate profiles (we define a new variable, “vertical fluctuation energy (VE)”), we can identify convection sources in climatological analyses. Analysis of a 9-year time

Jie Gong; Marvin A. Geller

2010-01-01

220

Gravity Virgins  

NASA Astrophysics Data System (ADS)

As an exercise in imagining a first encounter with gravity, let's begin with the barest gravitational circumstance. On a planet-sized spherical mass we find rigid poles extending to astronomical distances. At regular intervals along each pole there are Instrument Stations containing a clock, an accelerometer and light senders and receivers. Now imagine a civilization (the RC's) that has evolved in a huge self-sustaining Rotating Cylinder far removed from the sphere or any other astronomical body. The RC's are totally ignorant of gravity but understand well light propagation and the effect of motion on clocks, lengths, etc. Motion is sacred to the RC's because they know they'd die if their cylinder stopped rotating. Their clocks are synchronized so as to reflect the anisotropy of light sent in opposite directions along the cylinder's wall. When they set out to explore the Universe, they come upon the top of one of our tall poles. The RC's inspect the instruments, take data and leave their rocket off except when, in the nick of time, they turn it back on to navigate a soft landing. In their attempt to make sense of their experience, will they prefer a hypothesis resembling General Relativity or a hypothesis more like the one found at GravitationLab.com?

Benish, Richard

2008-05-01

221

Mixing Layer Formation near the Tropopause Due to Gravity Wave Critical Level Interactions in a Cloud-Resolving Model  

Microsoft Academic Search

A plausible mechanism for the formation of mixing layers in the lower stratosphere above regions of tropical convection is demonstrated numerically using high-resolution, two-dimensional (2D), anelastic, nonlinear, cloud-resolving simulations. One noteworthy point is that the mixing layer simulated in this study is free of anvil clouds and well above the cloud anvil top located in the upper troposphere. Hence, the

Mohamed Moustaoui; Binson Joseph; Hector Teitelbaum

2004-01-01

222

Autism Consumer Health Web Sites: Are Readability Levels Too High?  

Microsoft Academic Search

Are excessively high reading levels creating a barrier for parents seeking information about autism on the Internet? Although the average American reads at the eighth grade level, medical information is frequently written above the twelfth grade level. Readability of 14 autism consumer health Web sites was determined. The average reading score on the Flesch-Kincaid Grade Level Index was grade 11.9

Robin M. Sabo

2008-01-01

223

High Level Waste Canister Emplacement and Retrieval Concepts Study.  

National Technical Information Service (NTIS)

Several concepts are described for the interim (20 to 30 years) storage of canisters containing high level waste, cladding waste, and intermediate level-TRU wastes. It includes requirements, ground rules and assumptions for the entire storage pilot plant....

1975-01-01

224

The petrol approach to high-level power estimation  

Microsoft Academic Search

High-level power estimation is essential for designing complex low-power ICs. However, the lack of flexibility, or restriction to synthesizable code of previously presented high-level power estimation approaches limits their use. In this paper we present a novel, more general and flexible high-level power estimation approach, that avoids these limitations. Petrol, as we call it, is not limited to specialized application

Rafael Peset Llopis; Kees G. W. Goossens

1998-01-01

225

Safety handling characteristics of high-level tritiated water  

Microsoft Academic Search

In a fusion reactor, high-level tritiated water of more than one PBq\\/m3 will be generated and stored in various areas. The high-level tritiated water decomposes by itself and generates mainly hydrogen, becoming tritiated hydrogen peroxide water. In order to summarize safety requirements for long-term storage of high-level tritiated water, the characteristics, such as effective G-values of hydrogen and hydrogen peroxide,

T. Hayashi; T. Itoh; K. Kobayashi; K. Isobe; M. Nishi

2006-01-01

226

Artificial gravity.  

PubMed

NASA's Artificial Gravity program consists of a team of researchers from Wyle Laboratories, NASA Johnson Space Center, and the University of Texas Medical Branch (UTMB). The short-radius centrifuge (SRC), built by Wyle Laboratories, will be integrated with UTMB's conducted bedrest studies, which mimic the detrimental effects of weightlessness (or microgravity). Bedrest subjects will be spun on the SRC at various accelerations and for various time periods, while being monitored medically. Parameters such as bone loss, muscle atrophy, balance control, and oxygen consumption will then be compared in order to research ways of mitigating the impact on astronauts' physiology. Other potential benefits from these studies extend to population groups on Earth, such as bedridden patients. PMID:15852559

Scott, William B

2005-04-25

227

Gravity's rainbow  

NASA Astrophysics Data System (ADS)

Nonlinear special relativity (or doubly special relativity) is a simple framework for encoding properties of flat quantum spacetime. In this paper, we show how this formalism may be generalized to incorporate curvature (leading to what might be called 'doubly general relativity'). We first propose a dual to nonlinear realization of relativity in momentum space, and show that for such a dual the spacetime invariant is an energy-dependent metric. This leads to an energy-dependent connection and curvature, and a simple modification to Einstein's equations. We then examine solutions to these equations. We find the counterpart to the cosmological metric, and show how cosmologies based upon our theory of gravity may solve the 'horizon problem'. We discuss the Schwarzschild solution, examining the conditions for which the horizon is energy dependent. Finally, we find the weak field limit.

Magueijo, João; Smolin, Lee

2004-04-01

228

Massive Gravity: Theory and Cosmology  

NASA Astrophysics Data System (ADS)

The present thesis explores the theoretical and phenomenological aspects of theories of massive gravity in three and four spacetime dimensions. We start with investigating cosmology of a recently proposed class of four-dimensional nonlinear covariant extensions of Fierz-Pauli massive gravity. We begin with a short-distance, "decoupling" limit of the theory, describing the local dynamics of the universe. In this limit, the theory is a scalar-tensor model of a unique form defined by symmetries. We find that it admits a self-accelerated solution, with the Hubble parameter set by the graviton mass. The negative pressure causing the acceleration is due to a condensate of the helicity-0 component of the massive graviton, and the background evolution, in the approximation used, is indistinguishable from the ?CDM model. Fluctuations about the self-accelerated background are stable for a certain range of parameters involved. Most surprisingly, the fluctuation of the helicity-0 field decouples from an arbitrary source in the linearized theory, hiding the associated fifth force from any observer on this background. The local similarity with the ?CDM model however can not carry through beyond the horizon. The very same constraint, that eliminates the ghost, does not allow for truly homogeneous and isotropic FRW cosmologies in this class of theories. Nevertheless, at matter/radiation energy densities above a certain crossover value, these solutions follow the standard FRW evolution with a great accuracy, while the inhomogeneities become more and more pronounced as the density drops, and below the crossover value the evolution significantly departs from that of FRW. In the second part of the thesis, we explore the nonlinear classical dynamics of the three-dimensional theory of "New Massive Gravity". We find that the theory passes remarkably highly nontrivial consistency checks at the nonlinear level. We give a non-perturbative argument based on the presence of additional symmetries that the full theory does not lead to any extra degrees of freedom, suggesting that a 3D analog of the 4D Boulware-Deser ghost is not present in this theory. Last but not least, we generalize "New Massive Gravity" and construct a class of 3D cubic order massive models that retain the above properties.

Pirtskhalava, David

229

Gravity and height measurements along the profile of Damavand mountain in Iran  

Microsoft Academic Search

In order to model the earth gravity field, different gravity data with terrestrial, airborne and satellite gathered kinds are necessary. It is possible to recover by them the short, medium and long wavelengths of the gravity field respectively. Terrestrial gravity data, especially for the regions with highly variations, are useful for different purposes, i.e. to estimate the actual gravity range

Y. Hatam Chavari; Y. Djamour; A. M. Abolghasem; R. Bayer; P. Vanicek

2009-01-01

230

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

NASA Astrophysics Data System (ADS)

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

Hassan, Ahmed A.; Bahgat, Waleed M.

2010-01-01

231

Gravity and Mirror Gravity in Plebanski Formulation  

NASA Astrophysics Data System (ADS)

We present several theories of four-dimensional gravity in the Plebanski formulation, in which the tetrads and the connections are the independent dynamical variables. We consider the relation between different versions of gravitational theories: Einsteinian, "topological," "mirror" gravities and gravity with torsion. We assume that our world, in which we live, is described by the self-dual left-handed gravity, and propose that if the Mirror World exists in Nature, then the "mirror gravity" is the right-handed antiself-dual gravity. In this connection, we give a brief review of gravi-weak unification models. In accordance with cosmological measurements, we consider the Universe with broken mirror parity. We also discuss the problems of cosmological constant and communication between visible and mirror worlds. Investigating a special version of the Riemann-Cartan space-time, which has torsion as an additional geometric property, we have shown that in the Plebanski formulation the ordinary and dual "topological" sectors of gravity, as well as the gravity with torsion, are equivalent. Equations of motion are obtained. In this context, we have also discussed a "pure connection gravity" — a diffeomorphism-invariant gauge theory of gravity. Loop Quantum Gravity is also briefly reviewed.

Bennett, D. L.; Laperashvili, L. V.; Nielsen, H. B.; Tureanu, A.

2013-05-01

232

Observed quasi-steady kinetics of yeast cell growth and ethanol formation under very high gravity fermentation condition  

Microsoft Academic Search

Using a generalSaccharomyces cerevisiae as a model strain, continuous ethanol fermentation was carried out in a stirred tank bioreactor with a working volume of\\u000a 1,500 mL. Three different gravity media containing glucose of 120, 200 and 280 g\\/L, respectively, supplemented with 5 g\\/L\\u000a yeast extract and 3 g\\/L peptone, were fed into the fermentor at different dilution rates. Although complete

Li-Jie Chen; Ya-Li Xu; Feng-Wu Bai; William A. Anderson; Murray Moo-Young

2005-01-01

233

Gravity Behaves Like That?  

NASA Astrophysics Data System (ADS)

Many concepts of chaotic action in astrodynamics can be appreciated through simulations with home computers and software. Many astrodynamical cases are illustrated. Although chaos theory is now applied to spaceflight trajectories, this presentation employs only inert bodies with no onboard impulse, e.g., from rockets or outgassing. Other nongravitational effects are also ignored, such as atmosphere drag, solar pressure, and radiation. The ability to simulate gravity behavior, even if not completely rigorous, on small mass-market computers allows a fuller understanding of the new approach to astrodynamics by home astronomers, scientists outside orbital mechanics, and students in middle and high school. The simulations can also help a lay audience visualize gravity behavior during press conferences, briefings, and public lectures. No review, evaluation, critique of the programs shown in this presentation is intended. The results from these simulations are not valid for - and must not be used for - making earth-colliding predictions.

Pazmino, John

2007-02-01

234

Process for solidifying high-level nuclear waste  

DOEpatents

The addition of a small amount of reducing agent to a mixture of a high-level radioactive waste calcine and glass frit before the mixture is melted will produce a more homogeneous glass which is leach-resistant and suitable for long-term storage of high-level radioactive waste products.

Ross, Wayne A. (Richland, WA)

1978-01-01

235

Physical Activity Levels in Portuguese High School Physical Education  

ERIC Educational Resources Information Center

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

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

2012-01-01

236

Are High-Level Languages Suitable for Robust Telecoms Software?  

Microsoft Academic Search

In the telecommunications sector product development must minimise time to market while delivering high levels of dependability, availability, maintainability and scalability. High level languages are con- cise and hence potentially enable the fast production of maintainable software. This paper investigates the potential of one such language, Er- lang, to deliver robust distributed telecoms software. The evaluation is based on a

Jan Henry Nyström; Philip W. Trinder; David J. King

2005-01-01

237

Defense High Level Waste Disposal Container System Description Document  

Microsoft Academic Search

The Defense High Level Waste Disposal Container System supports the confinement and isolation of waste within the Engineered Barrier System of the Monitored Geologic Repository (MGR). Disposal containers are loaded and sealed in the surface waste handling facilities, transferred to the underground through the accesses using a rail mounted transporter, and emplaced in emplacement drifts. The defense high level waste

N. E. Pettit

2001-01-01

238

High-Performance Leadership at the Organization Level  

Microsoft Academic Search

The Problem and the Solution. High-performance leaders must have competencies to lead organization-level goal setting, design, and management This chapter descnbes two competency domains, strategic thinking and strategic stewardship, and nine competency groups that leaders must master to achieve high performance in an organization These competencies address Rummler and Brache's [1995] organization level of performance

Doris B. Collins; Janis S. Lowe; Carson R. Arnett

2000-01-01

239

High-level synthesis from VHDL with exact timing constraints  

Microsoft Academic Search

We present a solution to the interface timing problem in high-level synthesis by requiring that the algorithmic specification must completely determine the interface timing on the basis of cycles. We show how this approach has been integrated into the high-level synthesis system CA LLAS.

A. Stoll; Peter Duzy

1992-01-01

240

Testability Expertise and Test Planning from High-Level Specifications  

Microsoft Academic Search

The testability expertise of boards and ASICs (application-specific integrated circuits) relies on high-level models in the Prolog language. This high-level modeling makes it possible to describe chip and board functions at an adequate level of accuracy without giving useless details. Each chip is successfully considered as a test goal; difficult chips are identified. Design modifications in terms of multiplexers or

Michel Crastes De Paulet; M. Karam; Gabriele Saucier

1989-01-01

241

The Future of High-Level Modelling and System Level Design: Some Possible Methodology Scenarios  

Microsoft Academic Search

We discuss the future of high-level modelling in the context of system-level design, as the two concepts are inextricably interlinked. This is described as several possible methodology scenarios for the future of system level design as it unfolds within the electronics industry. Although these scenarios are presented as orthogonal, of course in actual fact the future may present us several

Grant Martin

242

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

ERIC Educational Resources Information Center

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

Archbald, Doug; Farley-Ripple, Elizabeth N.

2012-01-01

243

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

ERIC Educational Resources Information Center

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

Archbald, Doug; Farley-Ripple, Elizabeth N.

2012-01-01

244

Fusing high- and low-level features for speaker recognition  

Microsoft Academic Search

The area of automatic speaker recognition has been dominated by systems using only short-term, low-level acoustic information, such as cepstral features. While these systems have produced low error rates, they ignore higher levels of information beyond low-level acoustics that convey speaker information. Recently published works have demonstrated that such high-level information can be used successfully in automatic speaker recognition systems

Joseph P. Campbell; Douglas A. Reynolds; Robert B. Dunn

2003-01-01

245

Probable high ground-water levels on Cape Cod, Massachusetts  

USGS Publications Warehouse

Water-level records from 146 short-term (1 year) observation wells and 13 long-term (16-28 years) observation wells were used to estimate the probable high ground-water level that could occur at any site on Cape Cod. The estimation was based on correlation of a single water-level measurement from a test site with water-level records of the nine index wells. Maps showing areas of Cape Cod represented by the nine index wells and showing five ranges of water-level fluctuation are used in conjunction with tables of water-level adjustments to make the estimates. (USGS)

Frimpter, Michael H.

1980-01-01

246

Principled fusion of high-level model and low-level cues for motion segmentation  

Microsoft Academic Search

High-level generative models provide elegant descrip- tions of videos and are commonly used as the infer- ence framework in many unsupervised motion segmentation schemes. However, approximate inference in these models often require ad-hoc initialization to avoid local minima is- sues. Low-level cues, obtained independently from the high- level model, can constrain the search space and reduce the chance of inference

Arasanathan Thayananthan; Masahiro Iwasaki; Roberto Cipolla

2008-01-01

247

Proof of concept and performance optimization of high gravity batch-type centrifugal dryer for dewatering fine coal. Final report, September 20, 1989--September 21, 1991  

SciTech Connect

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

Smith, L.B.; Durney, T.

1991-12-31

248

Changes in cytokinin levels of Phalaenopsis leaves at high temperature  

Microsoft Academic Search

The effect of high temperatures on cytokinin levels in Phalaenopsishybrida leaves was investigated. Endogenous cytokinins were identified and quantified in Phalaenopsis leaves grown under high temperature conditions (30\\/25 °C day\\/night) using high performance liquid chromatography, bioassay and gas chromatography-selected ion monitoring-mass spectrometry. After 5 and 20 d of low temperature (25\\/20 °C day\\/night), zeatin, zeatin riboside and dihydrozeatin levels in the leaves were

Chin Chih Chou; Wen-Shaw Chen; Kuang-Liang Huang; Hsiao-Ching Yu; Li-Jen Liao

2000-01-01

249

Metabolic adaptation to long term changes in gravity environment  

NASA Astrophysics Data System (ADS)

Biochemical analyses of the brain of Cichlid fish larvae, exposed during their very early development for 7 days to an increased acceleration of 3g (hyper-gravity), revealed a decrease in brain nucleoside diphosphate kinase (NDPK) as well as creatine kinase (BB-CK) activity. Using high performance liquid chromatography (HPLC) the concentrations of adenine nucleotides (AMP, ADP, ATP), phosphocreatine (CP), as well as of nicotineamide adenine dinucleotides (NAD, NADP) were analyzed in the brain of hyper-g exposed larvae vs. 1g controls. A slight reduction in the total adenine nucleotides (TAN) as well as the adenylate energy charge (AEC) was found. In parallel a significant increase in the NAD concentration and a corresponding decrease in NADP concentration occurred in larva's hyper-g brains vs. 1g controls. These results give further evidence for an influence of gravity on cellular level and furthermore contribute to a clarification of the cellular signal-response chain for gravity perception.

Slenzka, K.; Appel, R.; Rahmann, H.

250

Concentrically zoned pattern in the Bouguer gravity anomaly map of northeastern North America  

Microsoft Academic Search

A concentrically zoned circular gravity high about 2,800 km in diameter is recognized in the gravity map of northeastern North America. The high consists of three major zones: a central region of high average gravity encircled by two belts of progressively lower average gravity outward from the high. Changes in surface geology occur across some of the zone boundaries, but

J. S. Klasner; K. J. Schulz

1982-01-01

251

[Impact of fermentation system initial status on oscillations in very high gravity ethanol continuous fermentation process and analysis of fermentation efficiency improvement].  

PubMed

Prior research reported the oscillatory behavior characterized by long period and high amplitude during high gravity continuous ethanol fermentations at the dilution rate of 0.027 h(-1). In this paper, high gravity continuous ethanol fermentations using Saccharomyces cerevisia at different dilution rates were carried out. Similar oscillations were observed when the dilution rate was switched to 0.04 h(-1). Both oscillatory and steady processes can be achieved at dilution rates of 0.027 or 0.04 h(-1), which depends on the initial status of the fermentation system. However, compared to steady process at the same dilution rate of 0.04 h(-1), the average residual sugar concentration was lowered by 14.8% for the oscillatory process, while the average ethanol concentration and productivity were increased by 12.6% and 12.3%, respectively. Further investigation revealed that besides the lag time, oscillatory processes were different from steady ones in kinetics because a higher specific growth rate can be achieved at the same residual sugar and ethanol concentrations (increased by 53.8% in average). PMID:20684303

Shen, Yu; Ge, Xumeng; Bai, Fengwu

2010-05-01

252

Reference commercial high-level waste glass and canister definition.  

SciTech Connect

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

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

1981-09-01

253

Reference commercial high-level waste glass and canister definition  

NASA Astrophysics Data System (ADS)

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

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

1981-09-01

254

National high-level waste systems analysis report  

SciTech Connect

This report documents the assessment of budgetary impacts, constraints, and repository availability on the storage and treatment of high-level waste and on both existing and pending negotiated milestones. The impacts of the availabilities of various treatment systems on schedule and throughput at four Department of Energy sites are compared to repository readiness in order to determine the prudent application of resources. The information modeled for each of these sites is integrated with a single national model. The report suggests a high-level-waste model that offers a national perspective on all high-level waste treatment and storage systems managed by the Department of Energy.

Kristofferson, K.; Oholleran, T.P.; Powell, R.H.

1995-09-01

255

Observations and WRF modelling of orographically-generated gravity waves above the Antarctic Peninsula during (OFCAP)  

NASA Astrophysics Data System (ADS)

Circumpolar westerly winds that dominate flow around Antarctica are known to provide favourable conditions for orographically-generated gravity waves when they encounter the high mountains of the Antarctic Peninsula. Downslope winds associated with these gravity waves are thought to impact the climate of the ice shelves east of the Peninsula, through the removal of low level clouds and cold continental air masses. As part of the Orographic flows and the Climate of the Antarctic Peninsula (OFCAP) field project, observations of gravity waves have been made in cross-peninsula flow at 67 degrees south using an instrumented Twin Otter aircraft, and radiosondes. Observations of gravity wave case studies will be presented and compared to high resolution (1.5 km) model forecasts using the Weather Research and Forecasting (WRF) numerical model to investigate the development several case studies.

Smith, V.; Mobbs, S.; Gadian, A.; Lachlan-Cope, T.; Ladkin, R.; Elvidge, A.

2012-04-01

256

Probable high ground-water levels in Massachusetts  

USGS Publications Warehouse

Water-level records from an observation-well network are analyzed for utility in estimating probable high ground-water levels in three different geohydrologic environments in Massachusetts. Analyses were made of 83 observation wells with between 8 and 37 years of records. Maximum annual water levels occur most frequently in March and April. The maximum range of water levels equaled or exceeded at 10 percent of randomly selected sites is estimated to be 16 feet in till, 9.2 feet in sand and gravel on terraces, and 4.0 feet in sand and gravel in valleys. An approach to estimating probable high ground-water levels at construction sites is suggested. An estimate of the high water level at a site may be derived by solving the proportion in which the ratio of the potential water-level rise at a test site to the potential water-level rise at an observation well is equal to the ratio of the water-level range at the site to the historic water-level range at an observation well in a similar geohydrologic environment. Precise description of the probabilities of exceedence of estimates made by this approach with the data available has not been made. Assuming that the data are representative of the future, estimates would not be expected to be exceeded at more than 1 in 10 sites over a period of 10 years or longer. (USGS)

Frimpter, M. H.

1981-01-01

257

Gravity gradient modeling using gravity and DEM  

Microsoft Academic Search

A model of the gravity gradient tensor at aircraft altitude is developed from the combination of ground gravity anomaly data\\u000a and a digital elevation model. The gravity data are processed according to various operational solutions to the boundary-value\\u000a problem (numerical integration of Stokes’ integral, radial-basis splines, and least-squares collocation). The terrain elevation\\u000a data are used to reduce free-air anomalies to

Lizhi Zhu; Christopher Jekeli

2009-01-01

258

High Response, Low Level Pulse Engine Thrust Stand System.  

National Technical Information Service (NTIS)

A high response, low level pulse engine thrust stand system has been designed, fabricated, and installed at the Air Force Flight Test Center, Rocket Propulsion Laboratory, Edwards Air Force Base. This system is designed to measure rocket engine thurst in ...

A. J. Couvillion J. D. Smith R. Kuberek

1966-01-01

259

Use of ARTEMIS with High-Level Applications.  

National Technical Information Service (NTIS)

ARTEMIS is an online accelerator modeling server developed at CEBAF. One of the design goals of ARTEMIS was to provide an integrated modeling environment for high- level accelerator diagnostic and control applications such as automated beam steering, Lina...

B. A. Bowling H. Shoaee S. Witherspoon

1995-01-01

260

Potential for erosion corrosion of SRS high level waste tanks.  

National Technical Information Service (NTIS)

SRS high-level radioactive waste tanks will not experience erosion corrosion to any significant degree during slurry pump operations. Erosion corrosion in carbon steel structures at reported pump discharge velocities is dominated by electrochemical (corro...

P. E. Zapp

1994-01-01

261

FEDEF: A High Level Architecture Federate Development Framework.  

National Technical Information Service (NTIS)

The development of High Level Architecture (HLA) federates can be repetitive and time consuming, with development time better spent on the aspects that differentiate the functionality provided by federates. The common tasks and design patterns involved in...

J. W. Van Spengen

2010-01-01

262

Organic Compounds in Savannah River Site High-Level Waste  

SciTech Connect

The present study identifies organic compounds or classes of compounds that may occur in SRS high-level waste (HLW) based on a review of previous sample analyses and records of disposals of organic compounds to the HLW tank farms.

Walker, D.D.

2002-12-17

263

Test Procedures for High Level Architecture Interface Specification.  

National Technical Information Service (NTIS)

This document contains test procedures for the High Level Architecture (HLA) Interface Specification, v1. 3. Section I discusses the terminology used, the organization of the procedures, and how the procedures are defined.

M. L. Loper

1998-01-01

264

Theory of Fermi Level Pinning of High-k Dielectrics  

Microsoft Academic Search

Fermi-level pinning of poly-Si and metal-silicide gate materials on Hf-based gate dielectrics has been systematically studied theoretically. Fermi-level pinning in high-work-function materials is governed by the O vacancy generation and subsequent formation of interface dipoles near gate electrodes due to the electron transfer. On the other hand, O interstitial formation plays a crucial role for Fermi-level pinning in low-work-function materials.

Kenji Shiraishi; H. Takeuchi; Y. Akasaka; Heiji Watanabe; N. Umezawa; T. Chikyow; Y. Nara; K. Yamada; Tsu-Jae King Liu

2006-01-01

265

Laboratory observations of gravity wave critical-layer flows  

Microsoft Academic Search

A new laboratory facility for studying gravity wave critical-layer interactions is described, and the results from one experiment are presented. In the experiment, a forced, monochromatic gravity wave is allowed to propagate into a stratified shear flow containing a critical level for the gravity wave. The early evoluation of the flow is characterized by turbulent wavebreaking and mean flow modifications

Donald P. Delisi; Timothy J. Dunkerton

1989-01-01

266

CEMENTITIOUS GROUT FOR CLOSING SRS HIGH LEVEL WASTE TANKS - #12315  

Microsoft Academic Search

In 1997, the first two United States Department of Energy (US DOE) high level waste tanks (Tanks 17-F and 20-F: Type IV, single shell tanks) were taken out of service (permanently closed) at the Savannah River Site (SRS). In 2012, the DOE plans to remove from service two additional Savannah River Site (SRS) Type IV high-level waste tanks, Tanks 18-F

C. Langton; H. Burns; D. Stefanko

2012-01-01

267

High-order level-spacing distributions for mixed systems  

Microsoft Academic Search

We apply some of the methods that have been successfully used to describe the nearest-neighbor-spacing distributions of levels of systems with mixed regular-chaotic dynamics to the calculation of high-order spacing distributions. The distributions for chaotic spectra are described in terms of a previously suggested generalization of Wigner's surmise, which assumes that the high-order level repulsion function is given by a

A. Y. Abul-Magd; M. H. Simbel

2000-01-01

268

Decision Document for Heat Removal from High Level Waste Tanks  

SciTech Connect

This document establishes the combination of design and operational configurations that will be used to provide heat removal from high-level waste tanks during Phase 1 waste feed delivery to prevent the waste temperature from exceeding tank safety requirement limits. The chosen method--to use the primary and annulus ventilation systems to remove heat from the high-level waste tanks--is documented herein.

WILLIS, W.L.

2000-07-31

269

Enforcing High-Level Security Properties for Applets  

Microsoft Academic Search

Smart card applications often handle privacy-sensitive information, and therefore must obey certain security policies. Typically, such policies are described as high-level security properties, stating for example that no pin verication must take place within a transaction. Behavioural interface specication languages, such as JML (Java Modeling Language), have been successfully used to validate functional properties of smart card applications. However, high-level

Mariela Pavlova; Gilles Barthe; Lilian Burdy; Marieke Huisman; Jean-louis Lanet

2004-01-01

270

Provably Correct High-level Timing Analysis Without Path Sensitization  

Microsoft Academic Search

This paper addresses the problem of true delay estimation during high level design. The existing delay estimation techniques ei- ther estimate the topological delay of the circuit which may be pes- simistic, or use gate-level timing analysis for calculating the true de- lay, which may be prohibitively expensive. We show that the paths in the implementation of a behavioral spec-

Subhrajit Bhattacharya; Sujit Dey; Franc Brglez

1994-01-01

271

Field Trips as Cognitive Motivators for High Level Science Learning  

ERIC Educational Resources Information Center

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

Hurley, Marlene M.

2006-01-01

272

Hierarchical High Level Information Fusion (H2LIFT).  

National Technical Information Service (NTIS)

The primary objective of this effort was the progression of Level 2/3 fusion of informational content to obtain an advanced multi-intelligent system for hierarchical high-level decision making processes. The goal was to develop an information integration ...

A. Crassidis A. Stotz J. Crassidis M. Sudit R. Nagi

2008-01-01

273

Discovery of high-level tasks in the operating room.  

PubMed

Recognizing and understanding surgical high-level tasks from sensor readings is important for surgical workflow analysis. Surgical high-level task recognition is also a challenging task in ubiquitous computing because of the inherent uncertainty of sensor data and the complexity of the operating room environment. In this paper, we present a framework for recognizing high-level tasks from low-level noisy sensor data. Specifically, we present a Markov-based approach for inferring high-level tasks from a set of low-level sensor data. We also propose to clean the noisy sensor data using a Bayesian approach. Preliminary results on a noise-free dataset of ten surgical procedures show that it is possible to recognize surgical high-level tasks with detection accuracies up to 90%. Introducing missed and ghost errors to the sensor data results in a significant decrease of the recognition accuracy. This supports our claim to use a cleaning algorithm before the training step. Finally, we highlight exciting research directions in this area. PMID:20060495

Bouarfa, L; Jonker, P P; Dankelman, J

2010-01-07

274

Nonlinear dynamics of 3D massive gravity  

NASA Astrophysics Data System (ADS)

We explore the nonlinear classical dynamics of the three-dimensional theory of "New Massive Gravity" proposed by Bergshoeff, Hohm and Townsend. We find that the theory passes remarkably highly nontrivial consistency checks at the nonlinear level. In particular, we show that: (1) In the decoupling limit of the theory, the interactions of the helicity-0 mode are described by a single cubic term — the so-called cubic Galileon — previously found in the context of the DGP model and in certain 4D massive gravities. (2) The conformal mode of the metric coincides with the helicity-0 mode in the decoupling limit. Away from this limit the nonlinear dynamics of the former is described by a certain generalization of Galileon interactions, which like the Galileons themselves have a well-posed Cauchy problem. (3) We give a non-perturbative argument based on the presence of additional symmetries that the full theory does not lead to any extra degrees of freedom, suggesting that a 3D analog of the 4D Boulware-Deser ghost is not present in this theory. Last but not least, we generalize "New Massive Gravity" and construct a class of 3D cubic order massive models that retain the above properties.

de Rham, Claudia; Gabadadze, Gregory; Pirtskhalava, David; Tolley, Andrew J.; Yavin, Itay

2011-06-01

275

The 3-D motion of the centre of gravity of the human body during level walking. I. Normal subjects at low and intermediate walking speeds.  

PubMed

OBJECTIVE: To measure the mechanical energy changes of the centre of gravity (CG) of the body in the forward, lateral and vertical direction during normal level walking at intermediate and low speeds. DESIGN: Eight healthy adults performed successive walks at speeds ranging from 0.25 to 1.75 m s(-1) over a dedicated force platform system. BACKGROUND: In previous studies, it was shown that the motion of the CG during gait can be altered more than the motion of individual segments. However, more detailed normative data are needed for clinical analysis. METHODS: The positive work done during the step to accelerate the body CG in the forward direction, W(f), to lift it, W(v), to accelerate it in the lateral direction, W(I), and the actual work done by the muscles to maintain its motion with respect to the ground ('external' work), W(ext), were measured. This allowed the calculation of the pendulum-like transfer between gravitational potential energy and kinetic energy of the CG, (percentage recovery, R). At the optimal speed of about 1.3 m s(-1), this transfer allows saving of as much as 65% of the muscular work which would have been otherwise needed to keep the body in motion with respect to the ground. The distance covered by the CG at each step either forward (step length, S(I)), or vertically (vertical displacement, S(v)) was also recorded. RESULTS: W(I) was, as a median, only 1.6-5.9% of W(ext). This ratio was higher, the lower the speed. At each step, W(ext) is needed to sustain two distinct increments of the total mechanical energy of the CG, E(tot). The increment a takes place during the double stance phase; the increment b takes place during the single stance phase. Both of these increments increased with speed. Over the speed range analyzed, the power spent to to sustain the a increment was 2.8-3.9 times higher than the power spent to sustain the b increment. PMID:11415774

Tesio, L; Lanzi, D; Detrembleur, C

1998-03-01

276

Supergravity computations without gravity complications  

NASA Astrophysics Data System (ADS)

The conformal compensator formalism is a convenient and versatile representation of supergravity (SUGRA) obtained by gauge-fixing conformal SUGRA. Unfortunately, practical calculations often require cumbersome manipulations of component field terms involving the full gravity multiplet. In this paper, we derive an alternative gauge fixing for conformal SUGRA which decouples these gravity complications from SUGRA computations. This yields a simplified tree-level action for the matter fields in SUGRA which can be expressed compactly in terms of superfields and a modified conformal compensator. Phenomenologically relevant quantities such as the scalar potential and fermion mass matrix are then straightforwardly obtained by expanding the action in superspace.

Cheung, Clifford; D'Eramo, Francesco; Thaler, Jesse

2011-10-01

277

A Testing Instrument for High School Arabic, Level III.  

ERIC Educational Resources Information Center

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

Wolowelsky, Joel B.

278

High-Level Modeling and Design of Asynchronous Interface Logic  

Microsoft Academic Search

Asynchronous digital interface circuits exhibit a high degree of concurrency. Self-timedimplementation is the most appropriate design discipline for such circuits. Their complexitydemands that a formal design methodology, amenable to automation, is used to designthem. Existing specification models suffer from severe limitations when it comes to describingthe circuit function at a high level, which requires decomposing the specification intointercommunicating sub-modules and

ALEXANDRE V. YAKOVLEV; ALBERT M. KOELMANS; Luciano Lavagno

1995-01-01

279

A Testing Instrument for High School Arabic, Level III.  

ERIC Educational Resources Information Center

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

Wolowelsky, Joel B.

280

Comparative leach testing of high-level waste forms  

SciTech Connect

Four candidate waste forms (borosilicate glass, high-silica glass, tailored ceramic, and Synroc) for Savannah River Plant high-level nuclear waste were compared in MCC-1 standard static leach tests. Relative leaching behavior differed for each element, and none of the waste forms was clearly superior to the others.

Stone, J A

1982-01-01

281

Talking About Gravity  

NSDL National Science Digital Library

The purpose of this assessment probe is to elicit students' ideas about gravity. The probe is designed to determine whether students recognize that gravity is a universal force that exists everywhere in space, regardless of whether air is present.

Eberle, Francis; Keeley, Page

2005-01-01

282

Induced gravity from gauge theories  

NASA Astrophysics Data System (ADS)

We discuss the possibility of a class of gauge theories, in four Euclidean dimensions, to describe gravity at quantum level. The requirement is that, at low energies, these theories can be identified with gravity as a geometrodynamical theory. Specifically, we deal with de Sitter-type groups and show that a Riemann-Cartan first order gravity emerges. An analogy with quantum chromodynamics is also formulated. Under this analogy it is possible to associate a soft BRST breaking to a continuous deformation between both sectors of the theory, namely, ultraviolet and infrared. Moreover, instead of hadrons and glueballs, the physical observables are identified with the geometric properties of spacetime. Furthermore, Newton and cosmological constants can be determined from the dynamical content of the theory.

Sobreiro, R. F.; Tomaz, A. A.; Vasquez Otoya, V. J.

2013-08-01

283

The effects of high presentation levels on consonant feature transmission  

NASA Astrophysics Data System (ADS)

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

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

2005-09-01

284

Building Level Administrators' Attitudes toward Teacher Effectiveness at the High School and Middle School Levels  

ERIC Educational Resources Information Center

This study investigated the attitudes of administrators about differences and similarities between middle and high school teachers. The research question that guided the study was, "Do attitudes about what makes an effective educator differ between building administrators at the middle and high school levels?" A formal, sequential, mixed-methods…

Hanson, Nathan K.

2010-01-01

285

Interpretations of suture zones in Norway and adjacent areas - results from new aeromagnetic and gravity compilations  

NASA Astrophysics Data System (ADS)

The Geological Survey of Norway (NGU) is releasing new aeromagnetic and gravity maps of Norway and adjacent sea areas. The aeromagnetic compilation consists of 22 onshore surveys and more than 40 offshore surveys. The vintage offshore surveys have been reprocessed with an innovative moving mean levelling technique. The gravity map is based on a total of 68.000 gravity stations on the mainland acquired by NGU, SK and Norwegian and foreign academic institutions in addition to more than 500.000 km of marine gravity profiles acquired by NPD, SK, TGS and Norwegian and foreign petroleum companies. We have produced an Airy isostatic residual map, enhancing crustal anomalies better than traditional free air and Bouguer anomaly maps. We have recognized that petrophysical measurements on core samples, hand specimens and in situ on bedrock exposures are essential for the interpretation of these anomalies. Petrophysical data (density, magnetic susceptibility and remanence) of 40.000 rock samples from the Norwegian mainland and susceptibility measurements of c. 7000 metres of cores from offshore drill holes have been acquired in order to constrain the interpretation of aeromagnetic and gravity data. Some of the most prominent gravity and magnetic anomalies in the region are attributed to lower crustal rocks occurring at a shallow level in the crust e.g. along the Lapland Granulite Belt in northern Fennoscandia, along the Bamble-Kongsberg Complex in southern Norway and in the Lofoten area. The emplacement of high grade and high-density lower crustal on top of upper crustal rocks produces a distinct gravity anomaly with a steep gradient along the suture zone and a much gentler gradient on the hinterland side. The asymmetry of the gravity anomalies along the Lapland Granulite Belt and Kongsberg-Bamble Complex, combined with the steep gradient, points to the over-thrusted high-grade and high-density granulites as the main source of the observed positive gravity anomaly. The Bouguer gravity anomaly associated with the Kongsberg-Bamble complex can be traced southwards through the Kattegat to the Scania region in southern Sweden. This asymmetric anomaly has previously been related to deep-seated mafic intrusions of Permian age. Our new suture zone interpretation is in accordance with reflection seismic data from northern Skagerrak and Bornholm areas. The regional suture zones were later reactivated as continental rifts. This concept of gravity field modeling can also be applied to the mid-Norwegian continental shelf and partially explain the observed high-density rocks occurring below the Møre and Vøring basins and in the Lofoten area.

Olesen, O.; Brönner, M.; Ebbing, J.; Gernigon, L.

2009-04-01

286

Gravity is Geometry.  

ERIC Educational Resources Information Center

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

MacKeown, P. K.

1984-01-01

287

Basement interpretations from airborne magnetic and gravity data over the Lambert Rift region of East Antarctica  

NASA Astrophysics Data System (ADS)

Geological exposures in the Lambert Rift region of East Antarctica comprise scattered coastal outcrops and inland nunataks sporadically protruding through the Antarctic ice sheet from Prydz Bay to the southernmost end of the Prince Charles Mountains. This study utilized airborne magnetic, gravity, and ice radar data to interpret the distribution and architecture of tectonic terranes that are largely buried beneath the thick ice sheet. Free-air and Bouguer gravity data are highly influenced by the subice and mantle topography, respectively. Gravity stripping facilitated the removal of the effect of ice and Moho, and the residual gravity data set thus obtained for the intermediate crustal level allowed a direct comparison with magnetic data. Interpretation of geophysical data also provided insight into the distribution and geometry of four tectonic blocks: namely, the Vestfold, Beaver, Mawson, and Gamburtsev domains. These tectonic domains are supported by surface observations such as rock descriptions, isotopic data sets, and structural mapping.

McLean, M. A.; Wilson, C. J. L.; Boger, S. D.; Betts, P. G.; Rawling, T. J.; Damaske, D.

2009-06-01

288

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

National Technical Information Service (NTIS)

Most people take the constant presence of gravitys pull for granted. However, the Earth's gravitational strength actually varies from location to location. This variation occurs because mass, which influences an object's gravitational pull, is not evenly ...

F. Lemoine D. Smith D. Rowlands M. Zuber G. Neumann D. Chinn D. Pavlis

2000-01-01

289

Towards conformal loop quantum gravity  

NASA Astrophysics Data System (ADS)

A discussion is given of recent developments in canonical gravity that assimilates the conformal analysis of gravitational degrees of freedom. The work is motivated by the problem of time in quantum gravity and is carried out at the metric and the triad levels. At the metric level, it is shown that by extending the Arnowitt-Deser-Misner (ADM) phase space of general relativity (GR), a conformal form of geometrodynamics can be constructed. In addition to the Hamiltonian and Diffeomorphism constraints, an extra first class constraint is introduced to generate conformal transformations. This phase space consists of York's mean extrinsic curvature time, conformal three-metric and their momenta. At the triad level, the phase space of GR is further enlarged by incorporating spin-gauge as well as conformal symmetries. This leads to a canonical formulation of GR using a new set of real spin connection variables. The resulting gravitational constraints are first class, consisting of the Hamiltonian constraint and the canonical generators for spin-gauge and conformorphism transformations. The formulation has a remarkable feature of being parameter-free. Indeed, it is shown that a conformal parameter of the Barbero-Immirzi type can be absorbed by the conformal symmetry of the extended phase space. This gives rise to an alternative approach to loop quantum gravity that addresses both the conceptual problem of time and the technical problem of functional calculus in quantum gravity.

H-T Wang, Charles

2006-03-01

290

Emergent gravity: the BEC paradigm  

NASA Astrophysics Data System (ADS)

We study selected aspects of quantum gravity phenomenology inspired by the gravitational analogy in Bose--Einstein condensates (BECs). We first review the basic ideas and formalism of analogue gravity in BECs, with particular emphasis on the possibility of simulating black holes. The non-relativistic, 'superluminal' modifications of the dispersion relation in a BEC beyond the hydrodynamic limit make it a particularly interesting model for many scenarios of quantum gravity phenomenology which consider a possible violation of local Lorentz invariance at high energies. In particular, these modifications allow the study of kinematical corrections that such quantum gravity scenarios could impose on general relativity. A simple (1+1)-dimensional acoustic black hole configuration in a BEC is presented, and its dynamical stability and quasinormal mode spectrum are studied. Then, an analysis is performed of the Hawking radiation for a collapsing geometry in which a black hole is created. It is seen that the superluminality of the dispersion relation leads to a frequency-dependence of the horizon, which can cause strong qualitative and quantitative modifications with respect to the standard (Lorentz-invariant) Hawking spectrum. We end with some considerations related to the possibility of constructing a serious toy model for Planck-scale gravity understood as an emergent phenomenon, based on the condensed matter analogy. In particular, we discuss the problem of diffeomorphism invariance in such a seemingly background-dependent approach and indicate some possible ideas for how to recover the Einstein equations in the adequate limit.

Jannes, Gil

2009-07-01

291

Estimating the gravity model without gravity using panel data  

Microsoft Academic Search

This article examines the effects of zero trade on the estimation of the gravity model using both simulated and real data with a panel structure, which is different from the more conventional cross-sectional structure. We begin by showing that the usual log-linear estimation method can result in highly deceptive inference when some observations are zero. As an alternative approach, we

Joakim Westerlund; Fredrik Wilhelmsson

2011-01-01

292

Airborne Gravity Gradiometry Resolves a Full Range of Gravity Frequencies  

Microsoft Academic Search

Airborne Full Tensor Gradiometry (Air\\\\-FTGR) was flown at high altitude coincident with Airborne Gravity (AG) flown in 2003 in West Arnhem Land, Australia. A preliminary analysis of two data sets indicates that the Air\\\\-FTGR system has the capability of resolving intermediate to long wavelengths features that may be associated with relatively deeper geological structures. A comparison of frequency filtered slices

J. Mataragio; J. Brewster; J. Mims

2007-01-01

293

Mercury levels in high-end consumers of fish.  

PubMed Central

Consumption of food containing mercury has been identified as a health risk. The U.S. Environmental Protection Agency (U.S. EPA) and the National Academy of Sciences recommend keeping the whole blood mercury level < 5.0 microg/L or the hair level < 1.0 microg/g. This corresponds to a reference dose (RfD) of 0.1 microg/kg body weight per day. All patients in a 1-year period (n = 720) who came for an office visit in a private internal medicine practice in San Francisco, California, were evaluated for mercury excess using the current RfD. One hundred twenty-three patients were tested (93 females, 30 males). Of these, data were statistically analyzed for 89 subjects. Mercury levels ranged from 2.0 to 89.5 microg/L for the 89 subjects. The mean for 66 women was 15 microg/L [standard deviation (SD) = 15], and for 23 men was 13 microg/L (SD = 5); 89% had levels exceeding the RfD. Subjects consumed 30 different forms or types of fish. Swordfish had the highest correlation with mercury level. Sixty-seven patients with serial blood levels over time after stopping fish showed a decline in mercury levels; reduction was significant (p < 0.0001). A substantial fraction of patients had diets high in fish consumption; of these, a high proportion had blood mercury levels exceeding the maximum level recommended by the U.S. EPA and National Academy of Sciences. The mean level for women in this survey was 10 times that of mercury levels found in a recent population survey by the U.S. Centers for Disease Control and Prevention. Some children were > 40 times the national mean.

Hightower, Jane M; Moore, Dan

2003-01-01

294

Mercury levels in high-end consumers of fish.  

PubMed

Consumption of food containing mercury has been identified as a health risk. The U.S. Environmental Protection Agency (U.S. EPA) and the National Academy of Sciences recommend keeping the whole blood mercury level < 5.0 microg/L or the hair level < 1.0 microg/g. This corresponds to a reference dose (RfD) of 0.1 microg/kg body weight per day. All patients in a 1-year period (n = 720) who came for an office visit in a private internal medicine practice in San Francisco, California, were evaluated for mercury excess using the current RfD. One hundred twenty-three patients were tested (93 females, 30 males). Of these, data were statistically analyzed for 89 subjects. Mercury levels ranged from 2.0 to 89.5 microg/L for the 89 subjects. The mean for 66 women was 15 microg/L [standard deviation (SD) = 15], and for 23 men was 13 microg/L (SD = 5); 89% had levels exceeding the RfD. Subjects consumed 30 different forms or types of fish. Swordfish had the highest correlation with mercury level. Sixty-seven patients with serial blood levels over time after stopping fish showed a decline in mercury levels; reduction was significant (p < 0.0001). A substantial fraction of patients had diets high in fish consumption; of these, a high proportion had blood mercury levels exceeding the maximum level recommended by the U.S. EPA and National Academy of Sciences. The mean level for women in this survey was 10 times that of mercury levels found in a recent population survey by the U.S. Centers for Disease Control and Prevention. Some children were > 40 times the national mean. PMID:12676623

Hightower, Jane M; Moore, Dan

2003-04-01

295

Anisotropy in Gravity and Holography  

NASA Astrophysics Data System (ADS)

In this thesis, we examine the dynamical structure of Ho?ava-Lifshitz gravity, and investigate its relationship with holography for anisotropic systems. Ho?ava-Lifshitz gravity refers to a broad class of gravitational models that incorporate anisotropy at a fundamental level. The idea behind Ho?ava-Lifshitz gravity is to utilize ideas from the theory of dynamical critical phenomena into gravity to produce a theory of dynamical spacetime that is power-counting renormalizable, and is thus a candidate renormalizable quantum field theory of gravity. One of the most distinctive features of Ho?ava-Lifshitz gravity is that its group of symmetries consists not of the diffeomorphisms of spacetime, but instead of the group of diffeomorphisms that preserve a given foliation by spatial slices. As a result of having a smaller group of symmetries, HL gravity naturally has one more propagating degree of freedom than general relativity. The extra mode presents two possible difficulties with the theory, one relating to consistency, and the second to its viability as a phenomenological model. (1) It may destabilize the theory. (2) Phenomenologically, there are severe constraints on the existence of an extra propagating graviton polarization, as well as strong experimental constraints on the value of a parameter appearing in the dispersion relation of the extra mode. In the first part of this dissertation we show that the extra mode can be eliminated by introducing a new local symmetry which steps in and takes the place of general covariance in the anisotropic context. While the identification of the appropriate symmetry is quite subtle in the full non-linear theory, once the dust settles, the resulting theory has a spectrum which matches that of general relativity in the infrared. This goes a good way toward answering the question of how close Ho?ava-Lifshitz gravity can come to reproducing general relativity in the infrared regime. In the second part of the thesis we pursue the relationship between Ho?ava-Lifshitz gravity and holographic duals for anisotropic systems. A holographic correspondence is one that posits an equivalence between a theory of gravity on a given spacetime background and a field theory living on the "boundary" of that spacetime, which resides at infinite spatial separation from the interior. It is a non-trivial problem how to define this boundary, but in the case of relativistic boundary field theories, there is a well-known definition due to Penrose of the boundary which produces the geometric structure required to make sense of the correspondence. However, the proposed dual geometries to anisotropic quantum field theories have a Penrose boundary that is incompatible with the assumed correspondence. We generalize Penrose's approach, using concepts from Ho?ava-Lifshitz gravity, to spacetimes with anisotropic boundary conditions, thereby arriving at the concept of anisotropic conformal infinity that is compatible with the holographic correspondence in these spacetimes. We then apply this work to understanding the structure of holography for anisotropic systems in more detail. In particular, we examine the structure of divergences of a certain theory of gravity on Lifshitz space. We find, using our construction of anisotropic conformal infinity, that the appropriate geometric structure of the boundary is that of a foliated spacetime with an anisotropic metric complex. We then perform holographic renormalization in these spacetimes, yielding a computation of the divergent part of the effective action, and find that it exhibits precisely the structure of a Ho?ava-Lifshitz action. Moreover, we find that, for dynamical exponent z = 2, the logarithmic divergence gives rise to a conformal anomaly in 2+1 dimensions, whose general form is precisely that of conformal Ho?ava-Lifshitz gravity with detailed balance.

Melby-Thompson, Charles Milton

296

High-level software energy macro-modeling  

Microsoft Academic Search

This paper presents an efficient and accurate high-level software energy estimation methodology using the concept of characterization-based macro-modeling. In characterization-based macro-modeling, a function or sub-routine is characterized using an accurate lower-level energy model of the target processor, to construct a macro-model that relates the energy consumed in the function under consideration to various parameters that can be easily observed or

Tat Kee Tan; Anand Raghunathan; G. Lakishminarayana; Niraj K. Jha

2001-01-01

297

Solidification of Savannah River plant high level waste  

NASA Astrophysics Data System (ADS)

Authorization for construction of the Defense Waste Processing Facility (DWPF) is expected in FY-83. The optimum time for stage 2 authorization is about three years later. Detailed design and construction will require approximately five years for stage 1, with stage 2 construction completed about two to three years later. Production of canisters of waste glass would begin in 1988, and the existing backlog of high level waste sludge stored at SRP would be worked off by about the year 2000. Stage 2 operation could begin in 1990. The technology and engineering are ready for construction and eventual operation of the DWPF for immobilizing high level radioactive waste at Savannah River Plant (SRP). Proceeding with this project will provide the public, and the leadership of this country, with a crucial demonstration that a major quanitity of existing high level nuclear wastes can be safely and permanently immobilized.

Maher, R.; Shafranek, L. F.; Kelley, J. A.; Zeyfang, R. W.

1981-11-01

298

The Use of ARTEMIS with High-Level Applications  

SciTech Connect

ARTEMIS is an online accelerator modeling server developed at CEBAF. One of the design goals of ARTEMIS was to provide an integrated modeling environment for high- level accelerator diagnostic and control applications such as automated beam steering, Linac Energy management (LEM) and the fast feedback system. This report illustrates the use of ARTEMIS in these applications as well as the application interface using the EPICS cdev device support API. Concentration is placed on the design and implementation aspects of high- level applications which utilize the ARTEMIS server for information on beam dynamics. Performance benchmarks for various model operations provided by ARTEMIS are also discussed.

B. A. Bowling; H. Shoaee; S. Witherspoon

1995-10-01

299

High Level Waste (HLW) Feed Process Control Strategy  

SciTech Connect

The primary purpose of this document is to describe the overall process control strategy for monitoring and controlling the functions associated with the Phase 1B high-level waste feed delivery. This document provides the basis for process monitoring and control functions and requirements needed throughput the double-shell tank system during Phase 1 high-level waste feed delivery. This document is intended to be used by (1) the developers of the future Process Control Plan and (2) the developers of the monitoring and control system.

STAEHR, T.W.

2000-06-14

300

Analysis of the GRACE Gravity Sensor System  

NASA Astrophysics Data System (ADS)

The quality, strength and homogeneity of global gravity field models from the US-German gravity mission GRACE (Gravity Recovery and Climate Experiment, launched in 2002) is unprecedented and the derived models are superior to any previous satellite-only gravity field model. However, the predicted accuracy of these GRACE-only models (so-called GRACE baseline) has not yet been completely reached, thus still limiting a full geophysical exploitation of the GRACE mission data. Among others, the cause could lie in a degraded performance or interaction of elements of the gravity field sensor system. Another possible reason is that suboptimal signal processing methods have been applied. The gravity field sensor system consists of the K-Band distance measurements, the star sensor data for the orientation in inertial space, the accelerometer data and the GPS phase and code data. This investigation focuses on the analysis of the raw star sensor data and the related signal processing applied to generate higher level (so-called L1B) star sensor data which are used in the gravity recovery process. First, the performance of the raw star sensor data is discussed. Then the related signal processing is analyzed: In particular we investigate 1) the combination of star sensor data from the two available sensor heads aboard each GRACE satellite and 2) the combination of the star sensor and the angular acceleration data to derive improved(?) L1B star sensor data. The results are discussed and the expected impact on the gravity field recovery is evaluated.

Frommknecht, B.; Meyer, U.; Schmidt, R.; Flechtner, F.

2007-12-01

301

Evaluation of the Recent Local and Global Geoid Models in Iran based on the GPS/levelling and Vertical Gravity Components  

NASA Astrophysics Data System (ADS)

In order to improve the local geoid models, the selection of the best Global Geopotential Model (GGM) model for the region is essential, to be used in a combined solution from GGM and local gravimetric data. Also, a number of regional gravimetric geoid models have recently been determined for the Iran area, and a common problem is to select the best model, e.g. for engineering applications. We discuss these problems by taking advantage of 460 GPS/levelling points and 10 Laplace points as an external tool for validation of different global and local geoid models in the absolute and relative senses. By using relative comparisons of the height differences between precise levelling and GPS/geoid models we avoid possible unknown systematic effects between the different types of observables. Several high resolution GGMs published recently based on the recent satellite gravimetry data. The most important models are EGM2008 and EIGEN-6C models. The study shows that the EGM2008 mode fits the GPS/levelling data in Iran with the best absolute and relative accuracy among the GGMs. Among the local geoid models, the newly gravimetric Quasi-geoid model IRQ09 agrees considerably better with GPS/levelling than any of the other recent local geoid models. Its rms fit with GPS/levelling is 19 cm. Hence, we strongly recommend the use of this new model in any surveying engineering or GPS/levelling projects in the area.

Beheshty, S. A. H.; Beheshti, S. M.

2012-04-01

302

Absolute-gravity stations in Western Dronning Maud Land, Antarctica  

NASA Astrophysics Data System (ADS)

Absolute-gravity stations are an important part of the geodetic infrastructure of the Antarctic. They provide accurate starting values for gravity surveys performed e.g. for the determination of the geoid, for geological studies and for geophysical investigations. The time variation in gravity determined from repeated absolute-gravity measurements provides insights into the Glacial Isostatic Adjustment (GIA) and into solid Earth deformation due to variation in contemporary ice load. Given sufficient joint coverage with International Terrestrial Reference Frame (ITRF) sites, gravity rates in high latitudes could in principle provide an independent check of the geocentricity of the z-dot (velocities in the direction of the rotation axis of the Earth) of the ITRF. We review the absolute gravity stations in Western and Central Dronning Maud Land. The oldest station is at the Finnish base Aboa, with 5 measurements by the Finnish Geodetic Institute (FGI) starting with the FINNARP 1993 expedition. Measurements at Maitri (India) and Novolazarevskaya (Russia) were first performed in 2004 by the National Geophysical Research Institute (NGRI) of India, and by the FGI, respectively. In the season 2010/11 a new station was constructed at Troll (Norway). In the season 2011/12 the aforementioned four sites were occupied by the FG5-221 absolute gravimeter of the FGI. At Sanae IV (South Africa) there are previous occupations by the FG5-221, in 2003/4 and 2005/6. All these bases have continuous GNSS stations. Numerous supporting measurements have been made at the sites: microgravity networks, levelling and GNSS ties to excentres etc., for controlling the stability of the stations. At some sites, nearby glacier elevations were surveyed to monitor the attraction of the variable close-field snow and ice masses. We give a description of the sites and the measurements performed at them. The work has benefited from the co-operation in the COST Action ES0701 "Improved Constraints on Models of GIA".

Mäkinen, Jaakko; Rasindra, Ravik; Chand, Uttam; Tiwari, Virendra; Lukin, Valery; Anisimov, Michail; Melvaer, Yngve; Melland, Gudmund; Koivula, Hannu; Näränen, Jyri; Poutanen, Markku

2013-04-01

303

Low-Level Information and High-Level Perception: The Case of Speech in Noise  

PubMed Central

Auditory information is processed in a fine-to-crude hierarchical scheme, from low-level acoustic information to high-level abstract representations, such as phonological labels. We now ask whether fine acoustic information, which is not retained at high levels, can still be used to extract speech from noise. Previous theories suggested either full availability of low-level information or availability that is limited by task difficulty. We propose a third alternative, based on the Reverse Hierarchy Theory (RHT), originally derived to describe the relations between the processing hierarchy and visual perception. RHT asserts that only the higher levels of the hierarchy are immediately available for perception. Direct access to low-level information requires specific conditions, and can be achieved only at the cost of concurrent comprehension. We tested the predictions of these three views in a series of experiments in which we measured the benefits from utilizing low-level binaural information for speech perception, and compared it to that predicted from a model of the early auditory system. Only auditory RHT could account for the full pattern of the results, suggesting that similar defaults and tradeoffs underlie the relations between hierarchical processing and perception in the visual and auditory modalities.

Nahum, Mor; Nelken, Israel; Ahissar, Merav

2008-01-01

304

High levels of fluctuating asymmetry in isolated stickleback populations  

PubMed Central

Background Fluctuating asymmetry (FA), defined as small random deviations from the ideal bilateral symmetry, has been hypothesized to increase in response to both genetic and environmental stress experienced by a population. We compared levels of FA in 12 bilateral meristic traits (viz. lateral-line system neuromasts and lateral plates), and heterozygosity in 23 microsatellite loci, among four marine (high piscine predation risk) and four pond (zero piscine predation risk) populations of nine-spined sticklebacks (Pungitius pungitius). Results Pond sticklebacks had on average three times higher levels of FA than marine fish and this difference was highly significant. Heterozygosity in microsatellite markers was on average two times lower in pond (HE ? 0.3) than in marine (HE ? 0.6) populations, and levels of FA and heterozygosity were negatively correlated across populations. However, after controlling for habitat effect on heterozygosity, levels of FA and heterozygosity were uncorrelated. Conclusions The fact that levels of FA in traits likely to be important in the context of predator evasion were elevated in ponds compared to marine populations suggests that relaxed selection for homeostasis in ponds lacking predatory fish may be responsible for the observed habitat difference in levels of FA. This inference also aligns with the observation that the levels of genetic variability across the populations did not explain population differences in levels of FA after correcting for habitat effect. Hence, while differences in strength of selection, rather than in the degree of genetic stress could be argued to explain habitat differences in levels of FA, the hypothesis that increased FA in ponds is caused by genetic stress cannot be rejected.

2012-01-01

305

Testing Gravity Against Early Time Integrated Sachs-Wolfe Effect  

SciTech Connect

A generic prediction of general relativity is that the cosmological linear density growth factor D is scale independent. But in general, modified gravities do not preserve this signature. A scale dependent D can cause time variation in gravitational potential at high redshifts and provides a new cosmological test of gravity, through early time integrated Sachs-Wolfe (ISW) effect-large scale structure (LSS) cross correlation. We demonstrate the power of this test for a class of f(R) gravity, with the form f(R) = {lambda}{sub 1}H{sub 0}{sup 2} exp(-R/{lambda}{sub 2}H{sub 0}{sup 2}). Such f(R) gravity, even with degenerate expansion history to {Lambda}CDM, can produce detectable ISW effect at z {approx}> 3 and l {approx}> 20. Null-detection of such effect would constrain {lambda}{sub 2} to be {lambda}{sub 2} > 1000 at > 95% confidence level. On the other hand, robust detection of ISW-LSS cross correlation at high z will severely challenge general relativity.

Zhang, Pengjie; /Shanghai, Astron. Observ. /Fermilab

2005-11-01

306

A Preview of High School Level Economic Software.  

ERIC Educational Resources Information Center

|The purpose of this study was to locate and evaluate high-school-level economic software compatible with an Apple II or IIe computer. To identify software, computer searches were run, bibliographies were scanned, and reviews were collected. Only software that was recommended by some outside source was included in the evaluation. The following…

Kincade, Jeannine H.

307

Level 1 Tornado PRA for the High Flux Beam Reactor  

Microsoft Academic Search

This report describes a risk analysis primarily directed at providing an estimate for the frequency of tornado induced damage to the core of the High Flux Beam Reactor (HFBR), and thus it constitutes a Level 1 Probabilistic Risk Assessment (PRA) covering tornado induced accident sequences. The basic methodology of the risk analysis was to develop a ``tornado specific`` plant logic

G. E. Bozoki; C. S. Conrad

1994-01-01

308

Student Achievement Levels Climb at Ribault Senior High School.  

ERIC Educational Resources Information Center

Ribault (Florida) Senior High School has reported a dramatic increase in student achievement levels since implementing a comprehensive college preparation curriculum. Among the program changes that contributed to those gains are: (1) the establishment and consistent enforcement of a strong discipline program, including rules for student conduct, a…

Profiles, Programs & Products, 1983

1983-01-01

309

High level radioactive waste management facility design criteria  

Microsoft Academic Search

This paper discusses the engineering systems for the structural design of the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS). At the DWPF, high level radioactive liquids will be mixed with glass particles and heated in a melter. This molten glass will then be poured into stainless steel canisters where it will harden. This process will transform

N. A. Sheikh; S. R. Salaymeh

1993-01-01

310

High-level manpower movement and Japan's foreign aid.  

PubMed

"Japan's technical assistance programs to Asian countries are summarized. Movements of high-level manpower accompanying direct foreign investments by private enterprise are also reviewed. Proposals for increased human resources development include education and training of foreigners in Japan as well as the training of Japanese aid experts and the development of networks for information exchange." PMID:12285771

Furuya, K

1992-01-01

311

The Estuary Guide. Level 3: High School. Draft.  

ERIC Educational Resources Information Center

Estuaries are marine systems that serve as nurseries for animals, links in the migratory pathways, and habitat for a complex community of organisms. This curriculum guide intended for use at the high school level seeks to teach what estuaries are; provide opportunities to practice decision-making that affects estuaries; and encourage students to…

Alexander, Glen; And Others

312

Examination of High Quality Enlistees on a Recruiting District Level.  

National Technical Information Service (NTIS)

In this thesis two distinct analytical techniques were used to develop models to forecast the number of high quality nonprior service males enlisting monthly in the U.S. Navy on a recruiting district level. The Box-Jenkins methodology was applied to a mon...

R. E. Irlam

1984-01-01

313

A comparison of high-level waste form characteristics  

Microsoft Academic Search

There are currently about 1055 million curies of high-level waste with a thermal output of about 2950 kilowatts (KW) at four sites in the United States: West Valley Demonstration Project (WVDP), Savannah River Site (SRS), Hanford Site (HANF), and Idaho National Engineering Laboratory (INEL). These quantities are expected to increase to about 1200 million curies and 3570 kw by the

R. Salmon; K. J. Notz

1991-01-01

314

MIXING PROCESSES IN HIGH-LEVEL WASTE TANKS  

EPA Science Inventory

Flammable gases can be generated in DOE high-level waste tanks, including radiolytic hydrogen, and during cesium precipitation from salt solutions, benzene. Under normal operating conditions the potential for deflagration or detonation from these gases is precluded by purging and...

315

Hierarchical Test Pattern Generation Based on High-Level Primitives  

Microsoft Academic Search

It is demonstrated that the exploitation of high-level primitives (HLPs) and, in particular, of the knowledge concerning their function in ATPG (automatic test pattern generation) leads to significant improvements in implication, unique sensitization, and multiple backtrace. Motivated by this observation and the necessity of covering all faults inside HLPs, the authors present the extension of the ATPG system SOCRATES to

Thomas M. Sarfert; Remo G. Markgraf; Erwin Trischler; Michael H. Schulz

1989-01-01

316

High level radioactive waste: Doing something about it  

Microsoft Academic Search

In addition to a growing inventory of spent power reactor fuel, there are approximately 100 million gallons of high-level radioactive waste (HLW) containing more than one billion curies of radioactivity stored in the United States today. This waste has been generated mainly from the production of plutonium and tritium and is primarily located on three federal sites. The waste is

G. G. Wicks; D. F. Bickford

1989-01-01

317

High Level Exploration of Quantum-Dot Cellular Automata (QCA)  

Microsoft Academic Search

In this work, we present a high level evaluation of an emerging nanotechnology to determine a set of technology requirements. The technology under question is Quantum-Dot Cellular Automata (QCA). As a vehicle, we present two different QCA circuits and evaluate the technology requirements based on the specifications of these circuits. These circuits are a simple 4-bit arithmetic logic unit (ALU)

K. Walus; G. Schulhof; G. A. Jullien

2004-01-01

318

Humanoid Robot Painter: Visual Perception and High-Level Planning  

Microsoft Academic Search

This paper presents visual perception discovered in high-level manipulator planning for a robot to reproduce the procedure involved in human painting. First, we apply a technique of 2D object segmentation that considers region similarity as an objective function and edge as a constraint with artificial intelligent used as a criterion function. The system can segment images more effectively than most

Miti Ruchanurucks; Shunsuke Kudoh; Koichi Ogawara; Takaaki Shiratori; Katsushi Ikeuchi

2007-01-01

319

Teaching for Higher Cognitive Level Learning in High School Science.  

ERIC Educational Resources Information Center

|Designed to focus on teaching for higher-level cognitive learning, this study measured student perceptions of psychosocial aspects of their classroom learning and involved a team of six researchers. The study consisted of an intensive 10-week investigation of two above-average science teachers in a suburban high school in Perth, Western…

Fraser, Barry J.

320

Life Extension of Aging High Level Waste (HLW) Tanks  

Microsoft Academic Search

The Double Shell Tanks (DSTs) play a critical role in the Hanford High-Level Waste Treatment Complex, and therefore activities are underway to protect and better understand these tanks. The DST Life Extension Program is focused on both tank life extension and on evaluation of tank integrity. Tank life extension activities focus on understanding tank failure modes and have produced key

D. Bryson; V. Callahan; M. Ostrom; W. Bryan; H. Berman

2002-01-01

321

High Level Waste Lag Storage and Feed Blending  

Microsoft Academic Search

SRTC performed small-scale tests to determine the behavior associated with blending streams in the High-level Waste (HLW) Lag Storage and Feed Blending Process System for the Hanford Waste Treatment and Immobilization Plant (WTP). The work reported here was planned and designed in response to the test specification. The Office of River Protection Hanford Waste Treatment and Immobilization Plant consists of

2004-01-01

322

Hanford high-level waste melter system evaluation data packages  

Microsoft Academic Search

The Tank Waste Remediation System is selecting a reference melter system for the Hanford High-Level Waste vitrification plant. A melter evaluation was conducted in FY 1994 to narrow down the long list of potential melter technologies to a few for testing. A formal evaluation was performed by a Melter Selection Working Group (MSWG), which met in June and August 1994.

M. L. Elliott; P. J. Shafer; D. A. Lamar; R. A. Merrill; W. Grunewald; G. Roth; W. Tobie

1996-01-01

323

Risk assessment methodology for Hanford high-level waste tanks  

Microsoft Academic Search

A methodology is presented for applying Probabilistic Safety Assessment techniques to quantification of the health risks posed by the high-level waste (HLW) underground tanks at the Department of Energy's Hanford reservation. This methodology includes hazard screening development of a list of potential accident initiators, systems fault trees development and quantification, definition of source terms for various release categories, and estimation

T. F. Bott; D. R. Mac Farlane; D. W. Stack; J. Kindinger

1992-01-01

324

Risk assessment methodology for Hanford high-level waste tanks  

Microsoft Academic Search

A methodology is presented for applying Probabilistic Safety Assessment techniques to quantification of the health risks posed by the high-level waste (HLW) underground tanks at the Department of Energy`s Hanford reservation. This methodology includes hazard screening development of a list of potential accident initiators, systems fault trees development and quantification, definition of source terms for various release categories, and estimation

T. F. Bott; D. R. Mac Farlane; D. W. Stack; J. Kindinger

1992-01-01

325

HADES-high-level architecture development and exploration system  

Microsoft Academic Search

The authors propose a new approach to high level behavioural synthesis starting from an algorithmic description in Hardware C. The algorithm is compiled into a corresponding data\\/control flow graph including several optimizations. The behavioural synthesis part of the system performs transformations like loop unrolling, parallelization, etc., whereby the user is supported through a feedback loop. For final structural synthesis an

P. Poechmueller; M. Held; N. Wehn; M. Glesner

1991-01-01

326

HLW (high-level waste) site characterization plan in Switzerland  

Microsoft Academic Search

The Swiss concept for high-level waste (HLW) disposal is based on the following important premises: (a) Spent fuel from a relatively small nuclear power program is reprocessed in facilities abroad; (b) the vitrified waste will be returned to Switzerland where an intermediate storage period of â40 yr allows adequate decay of radiation and heat production; potential sites are being selected

M. Thury; C. McCombie

1988-01-01

327

High-Level Radioactive Waste Fixation in Sintered Vitreous Matrix.  

National Technical Information Service (NTIS)

The safe storage of high-level wastes from fuel elements reprocessing includes, as a first step, the fixation of the same in materials having a good resistance to the leaching in aqueous medium, such as borosilicate glass. As an alternative to the usual m...

D. O. Russo N. Messi de Bernasconi M. A. Audero

1987-01-01

328

Space Augmentation of Military High-Level Waste Disposal.  

National Technical Information Service (NTIS)

Space disposal of selected components of military high-level waste (HLW) is considered. This disposal option offers the promise of eliminating the long-lived radionuclides in military HLW from the earth. A space mission which meets the dual requirements o...

E. Divita L. Lees T. English

1979-01-01

329

High-level nuclear waste management: analysis of options  

Microsoft Academic Search

A new approach is introduced for evaluating strategies for the safe disposal of high-level nuclear waste. Five strategies are considered, and by means of the effective method of 'analytic hierarchy process' these strategies are prioritized with respect to a set of tangible and intangible criteria. The results are compared with criteria adopted by the United States Department of Energy. The

T L Saaty; H Gholamnezhad

1982-01-01

330

Some high level language constructs for data of type relation  

Microsoft Academic Search

For the extension of high level languages by data types of mode relation, three language constructs are proposed and discussed: a repetition statement controlled by relations, predicates as a generalization of Boolean expressions, and a constructor for relations using predicates. The language constructs are developed step by step starting with a set of elementary operations on relations. They are designed

Joachim W. Schmidt; Universitiit Hamburg

1977-01-01

331

Teaching for Higher Cognitive Level Learning in High School Science.  

ERIC Educational Resources Information Center

Designed to focus on teaching for higher-level cognitive learning, this study measured student perceptions of psychosocial aspects of their classroom learning and involved a team of six researchers. The study consisted of an intensive 10-week investigation of two above-average science teachers in a suburban high school in Perth, Western Australia.…

Fraser, Barry J.

332

Time management in the DoD high level architecture  

Microsoft Academic Search

Recently, a considerable amount of effort in the U.S. Department of Defense has been devoted to defining the High Level Architecture (HLA) for distributed simulations. This paper describes the time management component of the HLA that defines the means by which individual simulations (called federates) advance through time. Time management includes synchronization mechanisms to ensure event ordering when this is

Richard M. Fujimoto; Richard M. Weatherly

1996-01-01

333

AN EMERGENCY MANAGEMENT DEMONSTRATOR USING THE HIGH LEVEL ARCHITECTURE  

Microsoft Academic Search

This paper addresses the issues of simulation interoperability within the emergency management training context. A prototype implementation in Java of a subset of the High Level Architecture (HLA) is described. The use of Web Browsers to provide graphical user interfaces to HLA is also investigated.

Roderick J. Williams

1996-01-01

334

A comparison of high-level waste form characteristics  

SciTech Connect

There are currently about 1055 million curies of high-level waste with a thermal output of about 2950 kilowatts (KW) at four sites in the United States: West Valley Demonstration Project (WVDP), Savannah River Site (SRS), Hanford Site (HANF), and Idaho National Engineering Laboratory (INEL). These quantities are expected to increase to about 1200 million curies and 3570 kw by the end of year 2020. Under the Nuclear Waste Policy Act, this high-level waste must ultimately be disposed of in a geologic repository. Accordingly, canisters of high-level waste immobilized in borosilicate glass or glass-ceramic mixtures are to be produced at the four sites and stored there until a repository becomes available. Data on the estimated production schedules and on the physical, chemical, and radiological characteristics of the canisters of immobilized high-level waste have been collected in OCRWM's Waste Characteristics Data Base, including recent updates an revisions. Comparisons of some of these data for the four sites are presented in this report. 14 refs., 3 tabs.

Salmon, R.; Notz, K.J.

1991-01-01

335

High level glucose increases mutagenesis in human lymphoblastoid cells  

Microsoft Academic Search

Epidemiological data have suggested an increased cancer rates in diabetic patients, for which the underlying mechanism is poorly understood. We studied whether high level of glucose (HG) treatment that mimic the hyperglycemic condition in diabetes mellitus is mutagenic. Mutagenesis studies were carried out at both hypoxanthine phosphoribosyltransferase (hprt) and thymidine kinase (tk) loci. Role of p53 in HG-induced mutagenesis was

Ying Zhang; Junqing Zhou; Tieli Wang; Lu Cai

336

Geology of high-level nuclear waste disposal  

Microsoft Academic Search

The concept of geological disposal is set out by describing the major rock types in terms of their ability to isolate high-level nuclear waste. The advantages and problems posed by particular rock formations are explored and the design and construction of geological repositories is considered, along with the methods used to estimate their safety. It gives special consideration to the

Roxburgh

1988-01-01

337

Analytical macromodeling for high-level power estimation  

Microsoft Academic Search

This paper present a new macromodeling technique for high-level power estimation. Our technique is based on a parameterizable analytical model that relies exclusively on statistical information of the circuit's primary inputs. During estimation, the statistics of the required metrics are extracted from the input stream, and a power estimate is obtained by evaluating a model function that has been characterized

Guiseppe Bernacchia; Marios C. Papaefthymiou

1999-01-01

338

Analytical Macro-Modeling for High-Level Power Estimation  

Microsoft Academic Search

1 Abstract In this paper, we present a new analytical macro-modeling technique for high-level power estimation. Our technique is based on a parameterizable analytical model that relies exclusively on statistical information of the circuit' s pri- mary inputs. During estimation, the statistics of the re- quired metrics are extracted from the input stream and a power estimate is obtained by

Giuseppe Bernacchia; Marios C. Papaefthymiou

339

THE XAL INFRASTRUCTURE FOR HIGH LEVEL CONTROL ROOM APPLICATIONS  

SciTech Connect

XAL is a Java programming framework for building high-level control applications related to accelerator physics. The structure, details of implementation, and interaction between components, auxiliary XAL packages, and the latest modifications are discussed. A general overview of XAL applications created for the SNS project is presented.

Shishlo, Andrei P [ORNL; Allen, Christopher K [ORNL; Chu, Paul [Stanford University; Galambos, John D [ORNL; Pelaia II, Tom [ORNL

2009-01-01

340

The Estuary Guide. Level 3: High School. Draft.  

ERIC Educational Resources Information Center

|Estuaries are marine systems that serve as nurseries for animals, links in the migratory pathways, and habitat for a complex community of organisms. This curriculum guide intended for use at the high school level seeks to teach what estuaries are; provide opportunities to practice decision-making that affects estuaries; and encourage students to…

Alexander, Glen; And Others

341

Interpreting a Dynamic and Uncertain World: High-Level Vision  

Microsoft Academic Search

When interpreting a dynamic and uncertain world it is important to have a high-level vision component that can guide the reasoning of the whole vision system. This guidance is provided by an attentional mechanism that exploits knowledge of the specific problem being solved. Here we survey work relevant to the development of such an attentional mechanism, using surveillance as an

Richard J. Howarth

1995-01-01

342

Teaching UML Modeling Before Programming at the High School Level  

Microsoft Academic Search

This paper describes experience teaching modeling at the high school level prior to teaching programming and embedded control. An implementation- independent form of UML modeling is being used to teach students to analyze various applications, systems and problem domains. The objective is to introduce the abstract thinking processes involved in modeling before introducing the more concrete thought processes involved in

Cortland Starrett

2007-01-01

343

Testing the half-scale model of the defense high level waste transportation cask  

SciTech Connect

Large quantities of defense high level waste (DHLW) produced at reprocessing sites of the US Department of Energy (DOE) exist at various locations across the country. In response to the need for a safe and efficient transportation system for this waste, a program was initiated by DOE at Sandia National Laboratories (SNL) in 1979 to design, test, and certify a Type B shipping system. This report presents the results of the testing of the half-scale model of this single containment design. The testing, conducted at Sandia National Laboratories' Coyote Test Facility, included 9 m (30 ft) drop tests and 1 m (40 in.) puncture tests as defined in Title 10 Code of Federal Regulations Part 71. The orientations for the drop tests were: bottom end, closure end (performed at -29/sup 0/C (-20/sup 0/F)), side no. 1, center of gravity over bottom corner, and side no. 2. The puncture tests were conducted at two orientations on the cask closure. All instrumentation and dimensional measurement values documented in this report are for the half-scale model. The instrumentation devices used to evaluate the structural response of the cask included accelerometers, strain gages, strain-gaged closure bolts, and linear variable differential transformers. Nondestructive examinations included: leakage testing of the cask closure seals, cavity gas sample port welds, and cask body welds; radiographs of the cask body weldments and depleted uranium shield liner; and dimensional inspections of all components and assemblies. Report contains test data on microfiche. 3 refs.

Madsen, M.M.; Uncapher, W.L.; Stenberg, D.R.; Baynes, E.E.

1987-08-01

344

Assigning Blame: Mapping Performance to High Level Parallel Programming Abstractions  

NASA Astrophysics Data System (ADS)

Parallel programs are increasingly being written using programming frameworks and other environments that allow parallel constructs to be programmed with greater ease. The data structures used allow the modeling of complex mathematical structures like linear systems and partial differential equations using high-level programming abstractions. While this allows programmers to model complex systems in a more intuitive way, it also makes the debugging and profiling of these systems more difficult due to the complexity of mapping these high level abstractions down to the low level parallel programming constructs. This work discusses mapping mechanisms, called variable blame, for creating these mappings and using them to assist in the profiling and debugging of programs created using advanced parallel programming techniques. We also include an example of a prototype implementation of the system profiling three programs.

Rutar, Nick; Hollingsworth, Jeffrey K.

345

High-Level Waste Vitrification Facility Feasibility Study  

SciTech Connect

A ''Settlement Agreement'' between the Department of Energy and the State of Idaho mandates that all radioactive high-level waste now stored at the Idaho Nuclear Technology and Engineering Center will be treated so that it is ready to be moved out of Idaho for disposal by a compliance date of 2035. This report investigates vitrification treatment of the high-level waste in a High-Level Waste Vitrification Facility based on the assumption that no more New Waste Calcining Facility campaigns will be conducted after June 2000. Under this option, the sodium-bearing waste remaining in the Idaho Nuclear Technology and Engineering Center Tank Farm, and newly generated liquid waste produced between now and the start of 2013, will be processed using a different option, such as a Cesium Ion Exchange Facility. The cesium-saturated waste from this other option will be sent to the Calcine Solids Storage Facilities to be mixed with existing calcine. The calcine and cesium-saturated waste will be processed in the High-Level Waste Vitrification Facility by the end of calendar year 2035. In addition, the High-Level Waste Vitrification Facility will process all newly-generated liquid waste produced between 2013 and the end of 2035. Vitrification of this waste is an acceptable treatment method for complying with the Settlement Agreement. This method involves vitrifying the waste and pouring it into stainless-steel canisters that will be ready for shipment out of Idaho to a disposal facility by 2035. These canisters will be stored at the Idaho National Engineering and Environmental Laboratory until they are sent to a national geologic repository. The operating period for vitrification treatment will be from the end of 2015 through 2035.

D. A. Lopez

1999-08-01

346

Gravity field modelling based on the spectral sensitivity of gravity related quantities- a new geoid model for Hungary  

NASA Astrophysics Data System (ADS)

In precise geoid modelling the combination of all available gravity related quantity is desired. A new quasi- geoid solution was developed for Hungary based on the spectral combination technique combining geopotential information, gravity and gravity gradient data sets in a complementary way. Based on the spectral sensitivity of gravity related quantities under consideration spectral weights for spectral combination were derived. To determine the geoid in the whole spectral band the specific integral kernels in the spectral domain were modified using the spectral weights and the calculations were based on 1D FFT spectral technique. In the combination of measurements, EGM2008 model was used exclusively to spherical harmonic degree 1000. Gravity data had superior performance up to degree about 4000 with respect to geopotential and gradient information, while the high- frequency part of the gravity signal stems from gravity gradient data in gravity field modelling.

Sz?cs, Eszter

2013-04-01

347

Iberia-Azores Gravity Model (IAGRM) using multi-source gravity data  

NASA Astrophysics Data System (ADS)

A consistent high precision and high resolution gravity model in the north-east Atlantic off Iberia peninsula using multi-source gravity data, ship-borne and satellite derived gravity anomalies, is presented. A solution strategy based on least squares optimal interpolation was used to assimilate into a coherent gravity model, gravity data with different spectral and spatial resolutions. Satellite derived gravity anomalies from KMS02 model, with an error covariance of 25 mGal2, and marine data carefully edited and validated by bias cross-over error adjustment, were used in this study. The observation error variance was determined from ship-borne track adjustment and assigned an independent value for each track determined from error variance propagation. Unbiased ship-borne gravity observations were assimilated into the satellite derived gravity KMS02 model by the least squares optimal interpolation algorithm (OI) with bias removed by applying a regional bias to all ship tracks (OI-b) and alternatively by constraining all ship tracks to KMS02 using bias and tilt (OI-t). External error of the model was determined by comparing with recent surveys and it was verified that OI-t approach improved the final gravity model to an accuracy of about 3 mGal. The effect of different merging approaches on geoid solution was also evaluated and it was verified that the merging process can contribute to improve the geoid accuracy up to 4 cm with the OI-t approach.

Catalao, J.

2006-03-01

348

Process induced deep-level defects in high purity silicon  

NASA Astrophysics Data System (ADS)

Deep-level defects appear in silicon upon heat treatment of wafers with surface disordered by mechanical lapping or introducing high concentration impurity in diffusion layer, i.e. in regimes typical of fabrication of high voltage devices. By means of capacitance transient spectroscopy, combined with other methods, it was shown that dominant electron traps with ionization energies of 0.28 and 0.54 eV of double level donor have low recombination activity, but affect the resistivity of high purity Si and play a key role in limiting the p-n junction breakdown voltage 0268-1242/13/5/008/img1. A careful study of the defect parameters showed their similarity to sulphur-related centres in Si.

Astrova, E. V.; Voronkov, V. B.; Kozlov, V. A.; Lebedev, A. A.

1998-05-01

349

Generalized sampling interpolation of noisy gravity/gravity gradient data  

NASA Astrophysics Data System (ADS)

The generalized sampling expansion (GSE) has been shown as a method for successfully interpolating combined gravity and gravity gradient data sets when the data are undersampled. The presence of noise on data sets renders such interpolation more difficult and many applications (known as expansions) of the GSE can be shown to intolerably amplify noise. However, many key expansions can be shown to successfully interpolate noisy data and even, given limited gradient error and sufficiently narrow line-spacing, reduce noise. These results can be shown to hold for both random noise and along-line correlated (levelling error type) noise. Unfortunately, the only expansion capable of interpolating a data set sampled at 3× conventional line-spacing, the Three-rectangle expansion, has a poor noise response and always acts to amplify data error. The GSE method bares up well against other methods of gradient enhanced interpolation; in numerical tests several expansions for the gravity field produce less noisy output than any of the pseudo-line, gradient enhanced minimum curvature or gradient enhanced Akima spline methods. Despite edge effects and using only gradient data with no gravity component, the GSE applied to real undersampled survey data bares up well against conventional interpolation, reducing noise where the data are clearly undersampled.

While, James; Biegert, Ed; Jackson, Andrew

2009-08-01

350

Superconducting gravity gradiometer for sensitive gravity measurements. I. Theory  

Microsoft Academic Search

Because of the equivalence principle, a global measurement is necessary to distinguish gravity from acceleration of the reference frame. A gravity gradiometer is therefore an essential instrument needed for precision tests of gravity laws and for applications in gravity survey and inertial navigation. Superconductivity and SQUID (superconducting quantum interference device) technology can be used to obtain a gravity gradiometer with

H. A. Chan; H. J. Paik

1987-01-01

351

Long-term management of high level wastes. [75 million gal of high level wastes presently stored by ERDA  

Microsoft Academic Search

As of Jan. 1976, some 75 million gal of high-level wastes were reported to be held in storage by ERDA. The options for treatments and long-range storage of radioactive wastes as studied at Hanford, Savannah River, and the Idaho National Engineering Laboratory were discussed. Typical compositions of the radioactive wastes at the three reprocessing sites were tabulated. (DDA)

M. S. Kearney; R. D. Jr. Walton

1976-01-01

352

CBIR: from low-level features to high-level semantics  

NASA Astrophysics Data System (ADS)

The performance of a content-based image retrieval (CBIR) system is inherently constrained by the features adopted to represent the images in the database. Use of low-level features can not give satisfactory retrieval results in many cases; especially when the high-level concepts in the user's mind is not easily expressible in terms of the low-level features. Therefore whenever possible, textual annotations shall be added or extracted and/or processed to improve the retrieval performance. In this paper a hybrid image retrieval system is presented to provide the user with the flexibility of using both the high-level semantic concept/keywords as well as low-level feature content in the retrieval process. The emphasis is put on a statistical algorithm for semantic grouping in the concept space through relevance feedback in the image space. Under this framework, the system can also incrementally learn the user's search habit/preference in terms of semantic relations among concepts; and uses this information to improve the performance of subsequent retrieval tasks. This algorithm can eliminate the need for a stand-alone thesaurus, which may be too large in size and contain too much redundant information to be of practical use. Simulated experiments are designed to test the effectiveness of the algorithm. An intelligent dialogue system, to which this algorithm can be a part of the knowledge acquisition module, is also described as a front end for the CBIR system.

Zhou, Xiang S.; Huang, Thomas S.

2000-04-01

353

Evaluation of recent global gravity field models  

NASA Astrophysics Data System (ADS)

The new gravity field model EGM2008 has been evaluated by comparisons with other, satellite-only as well as combined global gravity field models. Our evaluation comprises orbit adjustment tests, comparisons of the spectral behaviour, GPS/leveling tests and ocean geoid comparisons. In particular, this presentation focuses on the comparison of the EGM2008 with the latest EIGEN models EIGEN-5C and EIGEN-5S (EIGEN = European Improved Gravity model of the Earth by New techniques) which were achieved jointly by GFZ Potsdam and GRGS Toulouse.

Foerste, C.; Flechtner, F.; Stubenvoll, R.; Neumayer, H.; Raimondo, J.-C.; Koenig, R.; Barthelmes, F.; Dahle, C.; Kusche, J.; Biancale, R.

2009-04-01

354

A possible explanation of gravity anomalies over mid-ocean ridges  

Microsoft Academic Search

Gravity fields over the crests of slow spreading mid-ocean ridges are characterized by small amplitude free air gravity anomaly lows (30-70 mGal) with wavelengths of 40-60 km, flanked by smaller gravity highs. In general, the amplitude and wavelength of these gravity lows decrease with increasing spreading rate until, at fast spreading ridges (>5 cm\\/yr), free air gravity highs (10-20 mGal)

S. A. Hall; J. F. Casey; D. L. Elthon

1986-01-01

355

CRUSTAL STRUCTURE, FROM GRAVITY DATA, OF A COLLISION ZONE IN THE CENTRAL NEW HEBRIDES ISLAND ARC  

Microsoft Academic Search

Fonds Documentaire ORSTOM We investigate the main crustal structures involved in the collision zone of the eastern d'Entrecasteaus Zone with the central Nem Hebrides island arc, using primarily gravity data and supporting seismic-refraction and magnetic data. Over the arc, gravity anomalies trend north-south and include a comples western gravity high, a median gravity low, and an eastern gravity high. Large

Jean-Yves Collot; Michael A. Fisher

356

Upper crustal structure of the Tamworth Belt, New South Wales: constraints from new gravity data  

Microsoft Academic Search

New gravity data along five profiles across the western side of the southern New England Fold Belt and the adjoining Gunnedah Basin show the Namoi Gravity High over the Tamworth Belt and the Meandarra Gravity Ridge over the Gunnedah Basin. Forward modelling of gravity anomalies, combined with previous geological mapping and a seismic-reflection transect acquired by Geoscience Australia, has led

B. Guo; M. A. Lackie; R. H. Flood

2007-01-01

357

On unimodular quantum gravity  

NASA Astrophysics Data System (ADS)

Unimodular gravity is classically equivalent to standard Einstein gravity, but differs when it comes to the quantum theory: the conformal factor is non-dynamical, and the gauge symmetry consists of transverse diffeomorphisms only. Furthermore, the cosmological constant is not renormalized. Thus the quantum theory is distinct from a quantization of standard Einstein gravity. Here we show that within a truncation of the full renormalization group flow of unimodular quantum gravity, there is a non-trivial ultraviolet (UV)-attractive fixed point, yielding a UV completion for unimodular gravity. We discuss important differences to the standard asymptotic-safety scenario for gravity, and provide further evidence for this scenario by investigating a new form of the gauge-fixing and ghost sector. Communicated by P R L V Moniz

Eichhorn, Astrid

2013-06-01

358

The SuperSID project: exploiting high-level information for high-accuracy speaker recognition  

Microsoft Academic Search

The area of automatic speaker recognition has been dominated by systems using only short-term, low-level acoustic information, such as cepstral features. While these systems have indeed produced very low error rates, they ignore other levels of information beyond low-level acoustics that convey speaker information. Recently published work has shown examples that such high-level information can be used successfully in automatic

Douglas Reynolds; Walter Andrews; Joseph Campbell; Jiri Navratil; Barbara Peskin; Andre Adami; Qin Jin; David Klusacek; Joy Abramson; Radu Mihaescu; Jack Godfrey; Doug Jones; Bing Xiang

2003-01-01

359

High-level waste management technology program plan  

SciTech Connect

The purpose of this plan is to document the integrated technology program plan for the Savannah River Site (SRS) High-Level Waste (HLW) Management System. The mission of the SRS HLW System is to receive and store SRS high-level wastes in a see and environmentally sound, and to convert these wastes into forms suitable for final disposal. These final disposal forms are borosilicate glass to be sent to the Federal Repository, Saltstone grout to be disposed of on site, and treated waste water to be released to the environment via a permitted outfall. Thus, the technology development activities described herein are those activities required to enable successful accomplishment of this mission. The technology program is based on specific needs of the SRS HLW System and organized following the systems engineering level 3 functions. Technology needs for each level 3 function are listed as reference, enhancements, and alternatives. Finally, FY-95 funding, deliverables, and schedules are s in Chapter IV with details on the specific tasks that are funded in FY-95 provided in Appendix A. The information in this report represents the vision of activities as defined at the beginning of the fiscal year. Depending on emergent issues, funding changes, and other factors, programs and milestones may be adjusted during the fiscal year. The FY-95 SRS HLW technology program strongly emphasizes startup support for the Defense Waste Processing Facility and In-Tank Precipitation. Closure of technical issues associated with these operations has been given highest priority. Consequently, efforts on longer term enhancements and alternatives are receiving minimal funding. However, High-Level Waste Management is committed to participation in the national Radioactive Waste Tank Remediation Technology Focus Area. 4 refs., 5 figs., 9 tabs.

Harmon, H.D.

1995-01-01

360

RETENTION OF SULFATE IN HIGH LEVEL RADIOACTIVE WASTE GLASS  

SciTech Connect

High level radioactive wastes are being vitrified at the Savannah River Site for long term disposal. Many of the wastes contain sulfate at concentrations that can be difficult to retain in borosilicate glass. This study involves efforts to optimize the composition of a glass frit for combination with the waste to improve sulfate retention while meeting other process and product performance constraints. The fabrication and characterization of several series of simulated waste glasses are described. The experiments are detailed chronologically, to provide insight into part of the engineering studies used in developing frit compositions for an operating high level waste vitrification facility. The results lead to the recommendation of a specific frit composition and a concentration limit for sulfate in the glass for the next batch of sludge to be processed at Savannah River.

Fox, K.

2010-09-07

361

Management of data quality of high level waste characterization  

SciTech Connect

Over the past 10 years, the Hanford Site has been transitioning from nuclear materials production to Site cleanup operations. High-level waste characterization at the Hanford Site provides data to support present waste processing operations, tank safety programs, and future waste disposal programs. Quality elements in the high-level waste characterization program will be presented by following a sample through the data quality objective, sampling, laboratory analysis and data review process. Transition from production to cleanup has resulted in changes in quality systems and program; the changes, as well as other issues in these quality programs, will be described. Laboratory assessment through quality control and performance evaluation programs will be described, and data assessments in the laboratory and final reporting in the tank characterization reports will be discussed.

Winters, W.I., Westinghouse Hanford

1996-06-12

362

Multipurpose optimization models for high level waste vitrification  

SciTech Connect

Optimal Waste Loading (OWL) models have been developed as multipurpose tools for high-level waste studies for the Tank Waste Remediation Program at Hanford. Using nonlinear programming techniques, these models maximize the waste loading of the vitrified waste and optimize the glass formers composition such that the glass produced has the appropriate properties within the melter, and the resultant vitrified waste form meets the requirements for disposal. The OWL model can be used for a single waste stream or for blended streams. The models can determine optimal continuous blends or optimal discrete blends of a number of different wastes. The OWL models have been used to identify the most restrictive constraints, to evaluate prospective waste pretreatment methods, to formulate and evaluate blending strategies, and to determine the impacts of variability in the wastes. The OWL models will be used to aid in the design of frits and the maximize the waste in the glass for High-Level Waste (HLW) vitrification.

Hoza, M.

1994-08-01

363

Nondestructive examination of DOE high-level waste storage tanks  

SciTech Connect

A number of DOE sites have buried tanks containing high-level waste. Tanks of particular interest am double-shell inside concrete cylinders. A program has been developed for the inservice inspection of the primary tank containing high-level waste (HLW), for testing of transfer lines and for the inspection of the concrete containment where possible. Emphasis is placed on the ultrasonic examination of selected areas of the primary tank, coupled with a leak-detection system capable of detecting small leaks through the wall of the primary tank. The NDE program is modelled after ASME Section XI in many respects, particularly with respects to the sampling protocol. Selected testing of concrete is planned to determine if there has been any significant degradation. The most probable failure mechanisms are corrosion-related so that the examination program gives major emphasis to possible locations for corrosion attack.

Bush, S.; Bandyopadhyay, K.; Kassir, M.; Mather, B.; Shewmon, P.; Streicher, M.; Thompson, B.; van Rooyen, D.; Weeks, J.

1995-05-01

364

Life Extension of Aging High-Level Waste Tanks  

SciTech Connect

The Double Shell Tanks (DSTs) play a critical role in the Hanford High-Level Waste Treatment Complex, and therefore activities are underway to protect and better understand these tanks. The DST Life Extension Program is focused on both tank life extension and on evaluation of tank integrity. Tank life extension activities focus on understanding tank failure modes and have produced key chemistry and operations controls to minimize tank corrosion and extend useful tank life. Tank integrity program activities have developed and applied key technologies to evaluate the condition of the tank structure and predict useful tank life. Program results to date indicate that DST useful life can be extended well beyond the original design life and allow the existing tanks to fill a critical function within the Hanford High-Level Waste Treatment Complex. In addition the tank life may now be more reliably predicted, facilitating improved planning for the use and possible future replacement of these tanks.

Bryson, D.; Callahan, V.; Ostrom, M.; Bryan, W.; Berman, H.

2002-02-26

365

Long-term high-level waste technology  

NASA Astrophysics Data System (ADS)

Work performed at sites to immobilize high-level radioactive wastes is described. Program management and support with subtasks of management and budget, environmental and safety assessments, waste preparation, storage or disposal; waste retrieval, separation and concentration are discussed. Waste fixation and characterization, process and equipment development, final handling, canister development and characterization and onsite storage or disposal are also reported. Event trees defining possible accidents were completed in a safety assessment of continued in-tank storage of high-level waste. Two low-cost waste forms (tailored concrete and bitumen) were investigated as candidate immobilization forms. Comparative impact tests and leaching tests were also conducted on glasses, ceramics, and concretes. A process design description was written for the tailored ceramic process.

Corman, W. R.

1981-08-01

366

Radioactive high level waste insight modelling for geological disposal facilities  

NASA Astrophysics Data System (ADS)

Within this paper we present a simplified analytical model to provide insight into the key performance measures of a generic disposal system for high level waste within a geological disposal facility. The model assumes a low solubility waste matrix within a corrosion resistant disposal container surrounded by a low permeability buffer. Radionuclides migrate from the disposal area through a porous geosphere to the biosphere and give a radiological dose to a receptor. The system of equations describing the migration is transformed into Laplace space and an approximation used to determine peak values for the radionuclide mass transfer rate entering the biosphere. Results from the model are compared with those from more detailed numerical models for key radionuclides in the UK high level waste inventory. Such an insight model can provide a valuable second line of argument to assist in confirming the results of more detailed models and build confidence in the safety case for a geological disposal facility.

Carter, Alexander; Kelly, Martin; Bailey, Lucy

367

The Astronomy Diagnostic Test at the High School Level  

NASA Astrophysics Data System (ADS)

The Astronomy Diagnostic Test version 2, as a pre-test, has been used for several years to gauge the preparedness of students in the basic astronomy courses at many universities and colleges. Surprisingly, students at many levels of universities and colleges, from the most selective to the least selective, seem to do about the same on this test. Astronomy misconceptions would therefore seem to be as ubiquitous among the students most prepared for college in other subject areas as among those least prepared. Since the design of the test supposedly includes only concepts recognizable to most high-school graduates, it was decided to extend this test to the high school level. We wanted to see if the astronomical concepts became more recognizable as students progressed through their high school years or if those concepts, and misconceptions, were already in place when they entered high school. The test has been administered to several (non-astronomy) science classes from ninth through twelfth grade at a typical mid-western, non-selective, public high school in Ozark, Missouri. The results of this study will be presented.

Wolf, G. W.; Long, C.

2003-12-01

368

FLUIDIZED BED STEAM REFORMING ENABLING ORGANIC HIGH LEVEL WASTE DISPOSAL  

SciTech Connect

Waste streams planned for generation by the Global Nuclear Energy Partnership (GNEP) and existing radioactive High Level Waste (HLW) streams containing organic compounds such as the Tank 48H waste stream at Savannah River Site have completed simulant and radioactive testing, respectfully, by Savannah River National Laboratory (SRNL). GNEP waste streams will include up to 53 wt% organic compounds and nitrates up to 56 wt%. Decomposition of high nitrate streams requires reducing conditions, e.g. provided by organic additives such as sugar or coal, to reduce NOX in the off-gas to N2 to meet Clean Air Act (CAA) standards during processing. Thus, organics will be present during the waste form stabilization process regardless of the GNEP processes utilized and exists in some of the high level radioactive waste tanks at Savannah River Site and Hanford Tank Farms, e.g. organics in the feed or organics used for nitrate destruction. Waste streams containing high organic concentrations cannot be stabilized with the existing HLW Best Developed Available Technology (BDAT) which is HLW vitrification (HLVIT) unless the organics are removed by pretreatment. The alternative waste stabilization pretreatment process of Fluidized Bed Steam Reforming (FBSR) operates at moderate temperatures (650-750 C) compared to vitrification (1150-1300 C). The FBSR process has been demonstrated on GNEP simulated waste and radioactive waste containing high organics from Tank 48H to convert organics to CAA compliant gases, create no secondary liquid waste streams and create a stable mineral waste form.

Williams, M

2008-05-09

369

Case for retrievable high-level nuclear waste disposal  

USGS Publications Warehouse

Plans for the nation's first high-level nuclear waste repository have called for permanently closing and sealing the repository soon after it is filled. However, the hydrologic environment of the proposed site at Yucca Mountain, Nevada, should allow the repository to be kept open and the waste retrievable indefinitely. This would allow direct monitoring of the repository and maintain the options for future generations to improve upon the disposal methods or use the uranium in the spent fuel as an energy resource.

Roseboom, Jr. , Eugene, H.

1994-01-01

370

High-level constructs in the READY event notification system  

Microsoft Academic Search

This paper describes high-level constructs (operating overmultiple events, multiple consumers, etc.) provided byREADY, an event notification system being developed atAT&T Labs [7]. Entities in the READY model include: consumerspecifications that match over both single and compoundevent patterns; communication sessions that managequality of service (QoS) and ordering properties for eventdelivery; grouping constructs for both specifications and sessions;event domains and boundary routers...

Robert E. Gruber; Balachander Krishnamurthy; Euthimios Panagos

1998-01-01

371

High-Level Waste Systems Plan. Revision 7  

Microsoft Academic Search

This revision of the High-Level Waste (HLW) System Plan aligns SRS HLW program planning with the DOE Savannah River (DOE-SR) Ten Year Plan (QC-96-0005, Draft 8\\/6), which was issued in July 1996. The objective of the Ten Year Plan is to complete cleanup at most nuclear sites within the next ten years. The two key principles of the Ten Year

J. N. Brooke; M. V. Gregory; P. Paul; G. Taylor; F. E. Wise; N. R. Davis; M. N. Wells

1996-01-01

372

Security Mechanisms in High-Level Network Protocols  

Microsoft Academic Search

The implications of adding security mechanisms to high-level network protocols operating in an open-system environment are analyzed. First the threats to security that may arise in such an environment are described, and then a set of goals for communications security measures is established. This is followed by a brief description of the two basic approaches to communications security, link-oriented measures

Victor L. Voydock; Stephen T. Kent

1983-01-01

373

A Multithreaded Compiler Backend for High-level Array Programming  

Microsoft Academic Search

Whenever large homogeneous data structures need to be processed in a non-trivial way, e.g. in computational sci- ences, image processing, or system simulation, high-level array programming in the style of APL offers a far more concise and abstract approach than traditional scalar lan- guages such as C\\/C++ or FORTRAN-77. The same sort of applications often can also be characterized as

Clemens Grelck

2003-01-01

374

Design of secure operating systems with high security levels  

Microsoft Academic Search

Numerous Internet security incidents have shown that support from secure operating systems is paramount to fighting threats\\u000a posed by modern computing environments. Based on the requirements of the relevant national and international standards and\\u000a criteria, in combination with our experience in the design and development of the ANSHENG v4.0 secure operating system with\\u000a high security level (hereafter simply referred to

Sihan Qing; Changxiang Shen

2007-01-01

375

An appraisal of the Hanford high-level waste program  

Microsoft Academic Search

As set forth in the CPD Waste Management Program (HW-63958), new and improved methods of waste processing are planned to be initiated at Hanford. A major part of this program is concerned with the high-level wastes from the Purex Plant, with major objectives being the control of long-term hazards, the insurance of production continuity, and the attainment of positive waste

1960-01-01

376

Burning experiments and late Paleozoic high O2 levels  

Microsoft Academic Search

The Paleozoic rise of land plants brought about increased burial of organic matter and a resulting increase in atmospheric oxygen concentrations. Levels as high as 30-35% O2 may have been reached during the Permo-Carboniferous (Berner and Canfield, 1989; Berner, 2001). However, burning experiments based solely on paper (Watson, 1978) have challenged these results, the claim being that if the oxygen

R. Wildman; R. Essenhigh; R. Berner; L. Hickey; C. Wildman

2003-01-01

377

The ATLAS High Level Trigger infrastructure, performance and future developments  

Microsoft Academic Search

The ATLAS High Level Trigger (HLT) is a distributed real-time software system that performs the final online selection of events produced during proton-proton collisions at the Large Hadron Collider (LHC). It is designed as a two-stage event filter running on a farm of commodity PC hardware. Currently the system consists of about 850 multi-core processing nodes that will be extended

F. Winklmeier

2009-01-01

378

High Level System Design and Analysis Using Abstract State Machines  

Microsoft Academic Search

We provide an introduction to a practical method for rigorous system development which has been used successfully, under industrial\\u000a constraints, for design and analysis of complex hardware\\/software systems. The method allows one to start system development\\u000a with a trustworthy high level system specification and to link such a “ground model” in a well documented and inspectable\\u000a way through intermediate design

Egon Börger

1998-01-01

379

Expectation Grammars: Leveraging High-Level Expectations for Activity Recognition  

Microsoft Academic Search

Video-based recognition and prediction of a temporally ex- tended activity can benefit from a detailed description of high-level expectations about the activity. Stochastic gr am- mars allow for an efficient representation of such expecta- tions and are well-suited for the specification of temporall y well-ordered activities. In this paper, we extend stochast ic grammars by adding event parameters, state checks,

David Minnen; Irfan A. Essa; Thad Starner

2003-01-01

380

High-level CAD melds micromachined devices with foundries  

Microsoft Academic Search

The use of the Magic technology file to build transducer devices in the form of micro-heaters for use as IR pixels in a thermal display is described. Magic is a high-level computer-aided design (CAD) software system. The design methodology incorporated into the current MOSIS SCMOS technology file for Magic to implement the fabrication of silicon micromachined device structures is presented.

Janet C. Marshall; M. Parameswaran; M. E. Zaghloul; Michael Gaitan

1992-01-01

381

Using high-level tools to implement software engineering projects  

Microsoft Academic Search

Describes a one-semester software engineering course that takes advantage of the high-level programming tools that are becoming increasingly available. It has always been difficult to include necessary theoretical material as well as a complete software project in a one-semester course. In most traditional computer science degree programs, many students do not have room to take more than one semester of

Pearl Brazier

2000-01-01

382

Deep borehole disposal of high-level radioactive waste  

Microsoft Academic Search

Preliminary evaluation of deep borehole disposal of high-level radioactive waste and spent nuclear fuel indicates the potential for excellent long-term safety performance at costs competitive with mined repositories. Significant fluid flow through basement rock is prevented, in part, by low permeabilities, poorly connected transport pathways, and overburden self-sealing. Deep fluids also resist vertical movement because they are density stratified. Thermal

Joshua S. Stein; Geoffrey A. Freeze; Patrick Vane Brady; Peter N. Swift; Robert Paul Rechard; Bill Walter Arnold; Joseph F. Kanney; Stephen J. Bauer

2009-01-01

383

High-Level Mixed-Mode System Simulation in VHDL  

Microsoft Academic Search

This work describes a set of VHDL packages high-level modelling and simulation of systems containing both discrete-time and continuous-time subsystems. The work was motivated by the need to model and simulate a robot control system. The discrete-time portion of the system is modelled as a set of concurrent processes communicating via several well-defined inter-process communication primitives that form a more

Mani B. Srivastava; Robert W. Brodersen

384

Control of high level radioactive waste-glass melters  

Microsoft Academic Search

A necessary step in Defense Waste Processing Facility (DWPF) melter feed preparation for the immobilization of High Level Radioactive Waste (HLW) is reduction of Hg(II) to Hg(0), permitting steam stripping of the Hg. Denitrition and associated NOx evolution is a secondary effect of the use of formic acid as the mercury-reducing agent. Under certain conditions the presence of transition or

D. F. Bickford; C. J. Coleman; C. L. W. Hsu; R. E. Eibling

1990-01-01

385

High-level feature extraction in JPEG compressed domain  

NASA Astrophysics Data System (ADS)

Traditional feature extraction techniques like the KLT, Harris and Wavelet work only in the uncompressed domain. Hence an additional step of decompression is required before any of them could be applied. We propose a two-level technique for extracting high-level feature points directly from JPEG compressed images. At the first level, the Discrete Cosine Transform (DCT) blocks having high activity content are filtered using a variance measure. At the next level, a DCT block centered at every pixel present in the filtered block is constructed from the neighboring DCT blocks. Feature points are then selected by analyzing the AC coefficients of the DCT block centered about it. The proposed method is simple and efficient. The extracted feature points were found to be rich in information content, which could be used for image registration. The results of this technique showed almost the same amount of repeatability between two images with 60% to 70% overlap, when compared with techniques available in the uncompressed domain. The features thus extracted can directly be used to calculate the motion parameters between two images in the compressed domain.

Narayanan, C. K.; Prakash, M. C.; Prabhakara Rao, G. V.

2004-11-01

386

Canonical gravity with fermions  

NASA Astrophysics Data System (ADS)

Canonical gravity in real Ashtekar-Barbero variables is generalized to allow for fermionic matter. The resulting torsion changes several expressions in Holst’s original vacuum analysis, which are summarized here. This in turn requires adaptations to the known loop quantization of gravity coupled to fermions, which is discussed on the basis of the classical analysis. As a result, parity invariance is not manifestly realized in loop quantum gravity.

Bojowald, Martin; Das, Rupam

2008-09-01

387

Gravity over coronae and chasmata on Venus  

NASA Astrophysics Data System (ADS)

The global spherical harmonic model of Venus' gravity field MGNP60FSAAP, with horizontal resolution of about 600 km, shows that most coronae have little or no signature in the gravity field. Nevertheless, some coronae and some segments of chasmata are associated with distinct positive gravity anomalies. No corona has been found to have a negative gravity anomaly. The spatial coincidence of the gravity highs over four closely spaced 300- to 400-km-diameter coronae in Eastern Eistla Regio with the structures themselves is remarkable and argues for a near-surface or lithospheric origin of the gravity signals over such relatively small features. Apparent depths of compensation (ADCs) of the prominent gravity anomalies at Artemis, Latona, and Heng-o Coronae are about 150 to 200 km. The geoid/topography ratios (GTRs) at Artemis, Latona, and Heng-o Coronae lie in the range 32 to 35 m/km. The large ADCs and GTRs of Artemis, Latona, and Heng-o Coronae are consistent with topographically related gravity and a thick Venus lithosphere or shallowly compensated topography and deep positive mass anomalies due to subduction of underthrusting at these coronae. At arcuate segments of Hecate and Parga Chasmata ADCs are about 125 to 150 km, while those at Fauta Corona, four coronae in Eastern Eistla Regio, and an arcuate segment of Wester Parga Chasmata are about 75 km. The GTRs at Fauta Corona, the four coronae in eastern Eistla Regio, and the accurate segments of Hecate, Parga, and Western Parga Chasmata are about 12 to 21 m/km. By analogy with gravity anomalies of similar horizontal scale (600 km-several thousand kilometers) on the concave sides of terrestrial subduction zone arcs, which are due in large part to subducted lithosphere, it is inferred that the gravity anomalies on Venus are consistent with retrograde subduction at Artemis Chasma, along the northern and southern margins of Latona Coronam, and elsewhere along Parga and Hecate Chasmata.

Schubert, Gerald; Moore, William B.; Sandwell, David T.

1994-11-01

388

High precision calculation of helium and atom energy levels  

SciTech Connect

This work is concerned with the high-presicion calculation of the energies of the gound and excited states of the helium atom (or other light helium-like ions) to match the recent advances in experimental laser spectroscopic studies of transitions between these states with a precision of better than 10{sup {minus}4} cm{sup {minus}1}. At this level of accuracy it is essential to include mass-polarization effects through 2nd order, relativistic effects properly scaled by appropriate powers of the reduced mass, and quantum electrodynamic (QED) effects. In recent work on excited states of helium we have attained this level of accuracy for all the non-QED effects. Our results are in good agreement with those obtained independently by G. W. F. Drake. We are proceeding with a high-precision evaluation of the Bethe logarithm, which is the principal source of uncertainty in the theoretically determined QED effects. The refinement of these calculations at the 10{sup {minus}5} cm{sup {minus}1} level and beyond is expectd to stimulate further advances both theoretical and experimental, both in the calculations of 0({alpha}{sup 4}) Rydberg relativistic and QED effects and in the high-precision measurement of transition wavelengths.

Baker, J.; Hill, R.N.; Morgan, J.D. III (Department of Physics, University of Delaware, Newark, DE 19716 (USA))

1989-06-15

389

High levels of IL-7 cause dysregulation of thymocyte development  

PubMed Central

IL-7 signaling is required for thymocyte development and its loss has a severe deleterious effect on thymus function. Thymocyte–stromal cell interactions and other mechanisms tightly regulate IL-7 expression. We show that disruption of that regulation by over-expression of IL-7 inhibits T-cell development and promotes extensive B-cell lymphopoiesis in the thymus. Our data reveal that high levels of IL-7 negate Notch-1 function in thymocytes found in IL-7 transgenic mice and in co-culture with OP9-DL1 cells. While high levels of IL-7R are present on thymocytes, increased suppressor of cytokine signaling-1 expression blunts IL-7 downstream signaling, resulting in hypo-phosphorylation of proteins in the PI3K-Akt pathway. Consequently, GSK3? remains active and inhibits Notch-1 signaling as observed by decreased Hes-1 and Deltex expression in thymic progenitors. This is the first demonstration that high levels of IL-7 antagonize Notch-1 signaling and suggest that IL-7 may affect T- versus B-lineage choice in the thymus.

El-Kassar, Nahed; Flomerfelt, Francis A.

2012-01-01

390

Handbook of high-level radioactive waste transportation  

SciTech Connect

The High-Level Radioactive Waste Transportation Handbook serves as a reference to which state officials and members of the general public may turn for information on radioactive waste transportation and on the federal government`s system for transporting this waste under the Civilian Radioactive Waste Management Program. The Handbook condenses and updates information contained in the Midwestern High-Level Radioactive Waste Transportation Primer. It is intended primarily to assist legislators who, in the future, may be called upon to enact legislation pertaining to the transportation of radioactive waste through their jurisdictions. The Handbook is divided into two sections. The first section places the federal government`s program for transporting radioactive waste in context. It provides background information on nuclear waste production in the United States and traces the emergence of federal policy for disposing of radioactive waste. The second section covers the history of radioactive waste transportation; summarizes major pieces of legislation pertaining to the transportation of radioactive waste; and provides an overview of the radioactive waste transportation program developed by the US Department of Energy (DOE). To supplement this information, a summary of pertinent federal and state legislation and a glossary of terms are included as appendices, as is a list of publications produced by the Midwestern Office of The Council of State Governments (CSG-MW) as part of the Midwestern High-Level Radioactive Waste Transportation Project.

Sattler, L.R.

1992-10-01

391

Transient increase in the levels of gamma-tubulin complex in reorientation of cortical microtubules by gravity in azuki bean epicotyls  

NASA Astrophysics Data System (ADS)

Azuki bean (Vigna angularis Ohwi et Ohashi) seedlings were exposed to centrifugal hypergravity, and the changes in the orientation of cortical microtubules and the expression of genes cording ?-tubulin complex (VaTUBG and VaSpc98p) were examined. By 300 g treatment, the percentage of cells with transverse microtubules was decreased, while that with longitudinal microtubules was increased in epicotyls. Hypergravity increased the expression of VaTUBG and VaSpc98p transiently. Also, the expression of both genes was increased transiently by removal of hypergravity stimulus. Lanthanum and gadolinium ions, potential blockers of mechanosensitive calcium ion-permeable channels (mechanoreceptors), nullified reorientation of microtubules as well as up-regulation of expression of VaTUBG and VaSpc98p by hypergravity. These results suggest that mechanoreceptors on the plasma membrane may perceive the gravity signal, which leads to reorientation of cortical microtubules by transiently stimulating the formation of ?-tubulin complex.

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

392

Millimeter-Wave Measurements of High Level and Low Level Activity Glass Melts  

Microsoft Academic Search

The primary objectives of the current research is to develop on-line sensors for characterizing molten glass in high-level and low-activity waste glass melters using millimeter-wave (MMW) technology and to use this technology to do novel research of melt dynamics. Existing and planned waste glass melters lack sophisticated diagnostics due to the hot, corrosive, and radioactive melter environments. Without process control

Paul P. Woskov; S. K. Sundaram; Daniel William E. Jr

2006-01-01

393

A global view of stratospheric gravity wave hotspots located with Atmospheric Infrared Sounder observations  

NASA Astrophysics Data System (ADS)

The main aim of this study is to find and classify hotspots of stratospheric gravity waves on a global scale. The analysis is based on a 9 year record (2003 to 2011) of radiance measurements by the Atmospheric Infrared Sounder (AIRS) aboard NASA's Aqua satellite. We detect gravity waves based on 4.3 µm brightness temperature variances. Our method focuses on peak events, i.e., strong gravity wave events for which the local variance considerably exceeds background levels. We estimate the occurrence frequencies of these peak events for different seasons and time of day and use the results to find local maxima or "hotspots." In addition, we use AIRS radiances at 8.1 µm to simultaneously detect convective events, including deep convection in the tropics and mesoscale convective systems at middle latitudes. We classify the gravity wave sources based on seasonal occurrence frequencies for convection, but also by means of time series analyses and topographic data. Our study reproduces well-known hotspots of gravity waves, e.g., the Andes and the Antarctic Peninsula. However, the high horizontal resolution of the AIRS observations also allows us to locate numerous mesoscale hotspots, which are partly unknown or poorly studied so far. Most of these mesoscale hotspots are found near orographic features like mountain ranges, coasts, lakes, deserts, or isolated islands. This study will help to select promising regions and seasons for future case studies of gravity waves.

Hoffmann, L.; Xue, X.; Alexander, M. J.

2013-01-01

394

Halos of Modified Gravity  

NASA Astrophysics Data System (ADS)

We describe how a certain simple modification of general relativity, in which the local cosmological constant is allowed to depend on the space-time curvature, predicts the existence of halos of modified gravity surrounding spherically symmetric objects. We show that the gravitational mass of an object weighed together with its halo can be much larger than its gravitational mass as seen from inside the halo. This effect could provide an alternative explanation of the dark-matter phenomenon in galaxies. In this case, the local cosmological constant in the solar system must be some six orders of magnitude larger than its cosmic value obtained in the supernova type Ia experiments. This is well within the current experimental bounds, but may be directly observable in future high-precision experiments.

Krasnov, Kirill; Shtanov, Yuri

395

Various aspects of gravity  

NASA Astrophysics Data System (ADS)

This thesis summarizes research projects that I have been involved in during my graduate studies at Vanderbilt University. My research spanned different areas of theoretical high energy physics with gravity as a common denominator. I explore both fundamental and phenomenological aspects of: (i) mathematical physics where I have studied relations between partition functions of certain class of conformal field theories and Fischer-Griess Monster group; (ii) cosmology, where I performed a numerical study of a horizon size modes of scalar field; (iii) a black hole physics project involving possible extensions of the non-hair theorem in a presence of exotic types of scalar field; and (iv) a study of phenomenological space-time foam models and their relation to Planck scale physics.

Jankiewicz, Marcin

396

The Lighter Side of Gravity  

NASA Astrophysics Data System (ADS)

From the drop of an apple to the stately dance of the galaxies, gravity is omnipresent in the Cosmos. Even with its high profile, gravity is the most enigmatic of all the known basic forces in nature. The Lighter Side of Gravity presents a beautifully clear and completely nontechnical introduction to the phenomenon of this force in all its manifestations. Astrophysicist Jayant Narlikar begins with an historical background to the discovery of the law of gravitation by Isaac Newton in the seventeenth century. Using familiar analogies, interesting anecdotes, and numerous illustrations to get across subtle effects and difficult points to readers, he goes on to describe the general theory of relativity and some of its strange and unfamiliar ideas such as curved spacetime, the bending of light, and black holes. Since first publication in 1982 (W.H. Freeman), Dr. Narlikar has brought his book completely up to date and expanded it to include the discovery of gigantic gravitational lenses in space, the findings of the Cosmic Background Explorer (COBE) satellite, the detection of dark matter in galaxies, the investigation of the very early Universe, and other new ideas in cosmology. This lucid and stimulating book presents a clear approach to the intriguing phenomenon of gravity for everyone who has ever felt caught in its grip. Jayant Narlikar is the winner of many astronomical prizes and the author of Introduction to Cosmology (Cambridge University Press, 1993).

Narlikar, Jayant Vishnu

1996-10-01

397

Generalized modified gravity in large extra dimensions  

NASA Astrophysics Data System (ADS)

We discuss effective interactions among brane matter induced by modifications of higher-dimensional Einstein gravity through the replacement of Einstein Hilbert term with a generic function f(R,RR,RR) of the curvature tensors. We determine gravi-particle spectrum of the theory, and perform a comparative analysis of its predictions with those of the Einstein gravity within Arkani-Hamed Dvali Dimopoulos (ADD) setup. We find that this general higher-curvature quantum gravity theory contributes to scatterings among both massive and massless brane matter (in contrast to much simpler generalization of the Einstein gravity, f(R), which influences only the massive matter), and therefore, can be probed via various scattering processes at present and future colliders and directly confronted with the ADD expectations. In addition to collision processes which proceed with tree-level gravi-particle exchange, effective interactions among brane matter are found to exhibit a strong sensitivity to higher-curvature gravity via the gravi-particle loops. Furthermore, particle collisions with missing energy in their final states are found to be sensitive to additional gravi-particles not found in Einstein gravity. In general, road to a correct description of quantum gravity above Fermi energies depends crucially on if collider and other search methods end up with a negative or positive answer for the presence of higher-curvature gravitational interactions.

Aslan, Önder; Demir, Durmu? A.

2006-04-01

398

Massive Higher Derivative Gravity Theories  

Microsoft Academic Search

In this thesis massive higher derivative gravity theories are analyzed in some detail. One-particle scattering amplitude between two covariantly conserved sources mediated by a graviton exchange is found at tree-level in $D$ dimensional (Anti)-de Sitter and flat spacetimes for the most general quadratic curvature theory augmented with the Pauli-Fierz mass term. From the amplitude expression, the Newtonian potential energies are

Ibrahim Gullu

2012-01-01

399

Progress in the global standardization of gravity: an analysis of the Woollard and Rose international gravity values  

SciTech Connect

The history of improvements in the global standarization of gravity values since the advent of high range gravimeters in 1948 is reviewed. In particular the gravity base values given in SEG special publication International Gravity Measurements (Woolard and Rose, 1963) are evaluated against the most recent set of standarized gravity base values, The International Gravity Standardization Net, 1971 (Morelli et al, 1974). Adjunct IGSN 71 values prepared by the US Defense Mapping Agency Aerospace Center (unpublished) are also used to give a more comprehensive worldwide comparison of values.

Woollard, G.P.; Godley, V.M.

1980-12-01

400

Is 24,25(OH)D level really high in dialysis patients with high FGF23 levels?  

PubMed

Deficiency of 1,25-dihydroxyvitamin D [1,25(OH)(2)D] and excessive fibroblast growth factor (FGF23) are suggested to be associated with increased mortality in patients with chronic kidney disease (CKD). Generally, 24-hydroxylation has been considered the first step in the degradation pathway of 1,25(OH)(2)D and 25(OH)D. 24,25-dihydroxyvitamin D [24,25(OH)(2)D] was believed to be a degradation product, with no important biological effects. However, some data have accumulated showing that 24,25(OH)(2)D has biological effects on its own. Under conditions of eucalcemia, the synthesis of 24,25(OH)(2)D is increased, and the synthesis of 1,25(OH)(2)D is decreased. In patients with CKD, both high parathyroid hormone levels, which decrease the activity of enzyme CYP24A1 (24-hydroxylase), and high FGF23 levels, which increase the activity of enzyme CYP24A1, were often detected. However, information about 24,25(OH)(2)D levels in these patients is very limited. Whether compensatory changes in levels of FGF23 and 24,25(OH)(2)D in CKD patients are protective or harmful remain unknown issues. Therefore, more studies are needed to identify the nature of the interactions between these molecules and to fully elucidate their clinical significance. PMID:22467088

Taskapan, Hulya

2012-03-31

401

Permitting plan for the high-level waste interim storage  

SciTech Connect

This document addresses the environmental permitting requirements for the transportation and interim storage of solidified high-level waste (HLW) produced during Phase 1 of the Hanford Site privatization effort. Solidified HLW consists of canisters containing vitrified HLW (glass) and containers that hold cesium separated during low-level waste pretreatment. The glass canisters and cesium containers will be transported to the Canister Storage Building (CSB) in a U.S. Department of Energy (DOE)-provided transportation cask via diesel-powered tractor trailer. Tri-Party Agreement (TPA) Milestone M-90 establishes a new major milestone, and associated interim milestones and target dates, governing acquisition and/or modification of facilities necessary for: (1) interim storage of Tank Waste Remediation Systems (TWRS) immobilized HLW (IHLW) and other canistered high-level waste forms; and (2) interim storage and disposal of TWRS immobilized low-activity tank waste (ILAW). An environmental requirements checklist and narrative was developed to identify the permitting path forward for the HLW interim storage (HLWIS) project (See Appendix B). This permitting plan will follow the permitting logic developed in that checklist.

Deffenbaugh, M.L.

1997-04-23

402

Gravity field determination around the Japanese Antarctic stations by combining GOCE and in-situ gravity data  

NASA Astrophysics Data System (ADS)

GOCE (Gravity field and steady-state Ocean Circulation Explorer) satellite launched in March 2009 by ESA (European Space Agency) aims at improving static gravity fields, in particular at short wavelengths. In addition to its low-altitude orbit (250km), the sensitive gravity gradiometer installed is expected to reveal 1 mgal gravity anomaly and 1cm geoid at the spatial resolution of 100km (half wavelength). On the other hand, due to instrumental drifts, lack of reference points, and other reasons, the accuracy of in-situ gravity data (land, surface ship and airborne gravity data) is decreasing toward the longer wavelength more than several tens km. In particular in Antarctica where very few gravity reference points are available, the long wavelength accuracy and/or consistency among the data sets are quite limited. The Japanese Antarctic Research Expedition (JARE) has been conducting in-situ gravity measurements around the Japanese Antarctic stations for a long period. These measurements also suffered from such bad influence and they cause large errors in the long wavelength gravity fields, and, consequently, errors in geophysical and geodetic applications. This study aims at improveing the accuracy of the JARE gravity data using GOCE gravity models (level 2 EGMs). There are three different approaches for estimating the GOCE gravity models, namely, direct solution (DIR), time-wise solution (TIM) and space-wise solution (SPW). Among these, TIM never uses any a-priori information other than GOCE. Therefore we mainly employed TIM models (RL 1-3). We also employed EGM2008 as a reference. We show the comparisons between the gravity models and each of in-situ gravity data sets, and a preliminary result of the improved gravity field around Japanese Antarctic stations.

Fukuda, Y.; Nogi, Y.

2012-04-01

403

Holographic entanglement beyond classical gravity  

NASA Astrophysics Data System (ADS)

The Rényi entropies and entanglement entropy of 1+1 CFTs with gravity duals can be computed by explicit construction of the bulk spacetimes dual to branched covers of the boundary geometry. At the classical level in the bulk this has recently been shown to reproduce the conjectured Ryu-Takayanagi formula for the holographic entanglement entropy. We study the one-loop bulk corrections to this formula. The functional determinants in the bulk geometries are given by a sum over certain words of generators of the Schottky group of the branched cover. For the case of two disjoint intervals on a line we obtain analytic answers for the one-loop entanglement entropy in an expansion in small cross-ratio. These reproduce and go beyond anticipated universal terms that are not visible classically in the bulk. We also consider the case of a single interval on a circle at finite temperature. At high temperatures we show that the one-loop contributions introduce expected finite size corrections to the entanglement entropy that are not present classically. At low temperatures, the one-loop corrections capture the mixed nature of the density matrix, also not visible classically below the Hawking-Page temperature.

Barrella, Taylor; Dong, Xi; Hartnoll, Sean A.; Martin, Victoria L.

2013-09-01

404

High levels of ?-tocopherol in Norwegian alpine grazing plants.  

PubMed

Antioxidants prevent oxidation of fatty acids in milk and meat. In the present study, the content of tocopherol antioxidants (vitamin E) in vegetative and reproductive parts of 22 grazing plants was estimated in two alpine areas used for summer farming. The overall mean content of ?-tocopherol was 135 ± 34 ?g g(-1) DW, and grasses had much lower content (28 ± 11 ?g g(-1) DW) than herbs (215 ± 94 ?g g(-1) DW), sedges (186 ± 78 ?g g(-1) DW), and woody species (178 ± 52 ?g g(-1) DW). Highest and lowest species-specific levels were 649 ± 91 and 2 ± 1 ?g g(-1) DW, respectively. Plants from light and shady habitats did not differ in their ?-tocopherol content, which was idiosyncratic as indicated by significant interactions between species, sampling occasion, site, and tissue type. Our results show that alpine ranges provide fodder with high levels of ?-tocopherol. PMID:22775115

Sickel, Hanne; Bilger, Wolfgang; Ohlson, Mikael

2012-07-25

405

High level secretion of cellobiohydrolases by Saccharomyces cerevisiae  

PubMed Central

Background The main technological impediment to widespread utilization of lignocellulose for the production of fuels and chemicals is the lack of low-cost technologies to overcome its recalcitrance. Organisms that hydrolyze lignocellulose and produce a valuable product such as ethanol at a high rate and titer could significantly reduce the costs of biomass conversion technologies, and will allow separate conversion steps to be combined in a consolidated bioprocess (CBP). Development of Saccharomyces cerevisiae for CBP requires the high level secretion of cellulases, particularly cellobiohydrolases. Results We expressed various cellobiohydrolases to identify enzymes that were efficiently secreted by S. cerevisiae. For enhanced cellulose hydrolysis, we engineered bimodular derivatives of a well secreted enzyme that naturally lacks the carbohydrate-binding module, and constructed strains expressing combinations of cbh1 and cbh2 genes. Though there was significant variability in the enzyme levels produced, up to approximately 0.3 g/L CBH1 and approximately 1 g/L CBH2 could be produced in high cell density fermentations. Furthermore, we could show activation of the unfolded protein response as a result of cellobiohydrolase production. Finally, we report fermentation of microcrystalline cellulose (Avicel™) to ethanol by CBH-producing S. cerevisiae strains with the addition of beta-glucosidase. Conclusions Gene or protein specific features and compatibility with the host are important for efficient cellobiohydrolase secretion in yeast. The present work demonstrated that production of both CBH1 and CBH2 could be improved to levels where the barrier to CBH sufficiency in the hydrolysis of cellulose was overcome.

2011-01-01

406

Defense High Level Waste Disposal Container System Description Document  

SciTech Connect

The Defense High Level Waste Disposal Container System supports the confinement and isolation of waste within the Engineered Barrier System of the Monitored Geologic Repository (MGR). Disposal containers are loaded and sealed in the surface waste handling facilities, transferred to the underground through the accesses using a rail mounted transporter, and emplaced in emplacement drifts. The defense high level waste (HLW) disposal container provides long-term confinement of the commercial HLW and defense HLW (including immobilized plutonium waste forms [IPWF]) placed within disposable canisters, and withstands the loading, transfer, emplacement, and retrieval loads and environments. US Department of Energy (DOE)-owned spent nuclear fuel (SNF) in disposable canisters may also be placed in a defense HLW disposal container along with commercial HLW waste forms, which is known as co-disposal. The Defense High Level Waste Disposal Container System provides containment of waste for a designated period of time, and limits radionuclide release. The disposal container/waste package maintains the waste in a designated configuration, withstands maximum handling and rockfall loads, limits the individual canister temperatures after emplacement, resists corrosion in the expected handling and repository environments, and provides containment of waste in the event of an accident. Defense HLW disposal containers for HLW disposal will hold up to five HLW canisters. Defense HLW disposal containers for co-disposal will hold up to five HLW canisters arranged in a ring and one DOE SNF canister inserted in the center and/or one or more DOE SNF canisters displacing a HLW canister in the ring. Defense HLW disposal containers also will hold two Multi-Canister Overpacks (MCOs) and two HLW canisters in one disposal container. The disposal container will include outer and inner cylinders, outer and inner cylinder lids, and may include a canister guide. An exterior label will provide a means by which to identify the disposal container and its contents.

N. E. Pettit

2001-07-13

407

Superconducting tensor gravity gradiometer  

NASA Astrophysics Data System (ADS)

A sensitive gravity gradiometer can provide much needed gravity data of the earth and improve the accuracy of inertial navigation. A complete determination of all five independent components of the gravity gradient tensor is possible in principle by rotating a single in-line component gradiometer. In order to avoid dynamically induced noise sources arising from rotation, a hard-mounted assembly of component gradiometers may nevertheless be advantageous in an ultra-sensitive device. Superconductivity and other properties of materials at low temperatures can be used to obtain a sensitive, low-drift, gravity gradiometer. By differencing the outputs of accelerometer pairs using superconducting circuits, it is possible to construct a non-rotating tensor gravity gradiometer. Additional superconducting circuits can be provided to determine the linear and angular acceleration vectors. A three-axis in-line gravity gradiometer (a “vector” gradiometer) is being developed for satellite geodesy. A two-dimensional spring concept for a three-axis cross component gradiometer is discussed. The superconducting tensor gravity gradiometer constitutes a complete package of inertial navigation instruments with angular and linear acceleration readouts as well as gravity signals. Accuracy of inertial navigation could be improved by use of such a gradiometeraided inertial navigator.

Paik, H. J.

1981-12-01

408

Space travel and gravity  

Microsoft Academic Search

Space travelling is not possible for human because, by the time, we cross Jupiter, our bones dissolve as there is zero gravity and, by developing a gravity chamber in the space ship itself we will be able to travel in space for generations and explore the universe.

P. Karmakar; Greeninavin

2010-01-01

409

Demonstrating Reduced Gravity.  

National Technical Information Service (NTIS)

A miniature drop tower, Reduced-Gravity Demonstrator is developed to illustrate the effects of gravity on a variety of phenomena including the way fluids flow, flames burn, and mechanical systems (such as pendulum) behave. A schematic and description of t...

H. Pearlman D. Stocker D. Gotti D. Urban H. Ross T. Sours

1996-01-01

410

Demonstrating Reduced Gravity.  

ERIC Educational Resources Information Center

|Describes the construction of the Reduced-Gravity Demonstrator, which can be used to illustrate the effects of gravity on a variety of phenomena, including the way fluids flow, flames burn, and mechanical systems behave. Presents experiments, appropriate for classroom use, to demonstrate how the behavior of common physical systems change when…

Pearlman, Howard; And Others

1996-01-01

411

Cryogenic Gravity Meter.  

National Technical Information Service (NTIS)

The report describes the progress made towards the design and fabrication of a cryogenic gravity meter intended to have a sensitivity of about 25 millimicrogal. The cryogenic gravity meter consists of two parts--a suspension unit and a detection module. T...

V. S. Tuman

1970-01-01

412

Cryogenic Gravity Meter.  

National Technical Information Service (NTIS)

The report describes the progress made towards the design and fabrication of a cryogenic gravity meter intended to have a sensitivity of about 25 millimicrogal. The cryogenic gravity meter consists of two parts--a suspension unit and a detection module. T...

A. Waleh V. S. Tuman

1972-01-01

413

Gravity, Entropy, and Thermodynamics  

Microsoft Academic Search

The intrinsic motions of light, time, and gravity are primordial forms of entropy, causing: 1) the creation, expansion, and cooling of space; 2) the creation, expansion, and aging of history; 3) the creation and expansion of historic spacetime, respectively. The charges of matter are the symmetry debts of light (Noether's Theorem). Gravity pays the entropy-interest on matter's symmetry debt by

John A. Gowan

414

Weak lensing probes of modified gravity  

SciTech Connect

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

Schmidt, Fabian [Department of Astronomy and Astrophysics, University of Chicago, Chicago, Illinois 60637-1433 (United States) and Kavli Institute for Cosmological Physics, Chicago, Illinois 60637-1433 (United States)

2008-08-15

415

[The female urogenital system and high level sports].  

PubMed

High-level competition sports can have a variety of negative effects on the female urogenital apparatus. Perineal trauma is rare and is usually associated with certain sports (impalement or hydrotubation during water-skiing, indurated perineal nodules in racing cyclists, and horse-riders' perineum). Effort incontinence is seen in all sports involving abrupt repeated increases in intra-abdominal pressure that may exceed perineal floor resistance. Sportswomen should be questioned about possible incontinence and be informed of preventive and therapeutic measures. PMID:17450681

Crepin, Gilles; Biserte, Jacques; Cosson, Michel; Duchene, Franck

2006-10-01

416

High level waste partitioning studies at the research center Jülich  

NASA Astrophysics Data System (ADS)

Partitioning of high level radioactive waste (HLW) into long-lived and short-lived radionuclides is now under discussion as an alternative to conventional nuclear waste management concepts. This strategy aims at reducing the long term hazard potential of waste repositories. Basic experimental data of the partitioning systems, but also technical scale operations of the separation units are needed for a meaningful cost-risk-benefit assessment of such a strategy. In the ``Forschungszentrum Juelich,'' we focus on the decontamination of HLW solutions from the actinides including the non-recovered fuel components uranium and plutonium. .

Wenzel, Ulrich

2000-07-01

417

THE AMERICAN HIGH SCHOOL GRADUATION RATE: TRENDS AND LEVELS.  

PubMed

This paper applies a unified methodology to multiple data sets to estimate both the levels and trends in U.S. high school graduation rates. We establish that (a) the true rate is substantially lower than widely used measures; (b) it peaked in the early 1970s; (c) majority/minority differentials are substantial and have not converged for 35 years; (d) lower post-1970 rates are not solely due to increasing immigrant and minority populations; (e) our findings explain part of the slowdown in college attendance and rising college wage premiums; and (f) widening graduation differentials by gender help explain increasing male-female college attendance gaps. PMID:20625528

Heckman, James J; Lafontaine, Paul A

2010-05-01

418

High-level wastes: DOE names three sites for characterization  

SciTech Connect

DOE announced in May 1986 that there will be there site characterization studies made to determine suitability for a high-level radioactive waste repository. The studies will include several test drillings to the proposed disposal depths. Yucca Mountain, Nevada; Deaf Smith Country, Texas, and Hanford, Washington were identified as the study sites, and further studies for a second repository site in the East were postponed. The affected states all filed suits in federal circuit courts because they were given no advance warning of the announcement of their selection or the decision to suspend work on a second repository. Criticisms of the selection process include the narrowing or DOE options.

NONE

1986-07-01

419

High-Level Trigger for Electrons and Photons in CMS  

NASA Astrophysics Data System (ADS)

The CMS experiment will take data at the LHC proton proton collider, running at a centre-of-mass energy of 14 TeV. The CMS electromagnetic calorimeter (ECAL) is made of about 76000 PbWO4 crystals. The possibility to use the measured events for the physics studies relies on the robustness and efficiency of the triggering procedure. In this report the ElectronPhoton package of the ORCA framework (Object oriented Reconstruction for CMS Analysis) is presented and results from full simulation studies of the High-Level Trigger procedures to reconstruct and select electrons and photons are given.

CMS Collaboration

2006-01-01

420

High Level Waste (HLW) Transfer Staging Alternatives Assessment  

SciTech Connect

This document identifies potentially problematic transfers of high level waste (HLW) to the Waste Treatment Plant and assesses whether simple staging alternatives are available to resolve them. The problematic transfers are those transfers that could exceed allowable transfer-line operating pressures at the predicted critical velocity. If the actual waste properties for these transfers approach the bounding properties used in prior analysis, then there are no simple staging alternatives to resolve the problematic transfers. However, several alternatives were suggested that could work if it can be demonstrated that the actual median particle size is significantly less that the bounding value.

WILLIS, W.L.

2001-02-01

421

High level waste at Hanford: Potential for waste loading maximization  

SciTech Connect

The loading of Hanford nuclear waste in borosilicate glass is limited by phase-related phenomena, such as crystallization or formation of immiscible liquids, and by breakdown of the glass structure because of an excessive concentration of modifiers. The phase-related phenomena cause both processing and product quality problems. The deterioration of product durability determines the ultimate waste loading limit if all processing problems are resolved. Concrete examples and mass-balance based calculations show that a substantial potential exists for increasing waste loading of high-level wastes that contain a large fraction of refractory components.

Hrma, P.R.; Bailey, A.W.

1995-09-01

422

Solidification of Savannah River Plant high-level waste  

SciTech Connect

The Department of Energy, in accord with recommendations from the Du Pont Company, has started construction of a Defense Waste Processing Facility (DWPF) at the Savannah River Plant. The facility should be completed by the end of 1988, and full-scale operation should begin in 1990. This facility will immobilize in borosilicate glass the large quantity of high-level radioactive waste now stored at the plant plus the waste to be generated from continued chemical reprocessing operations. The existing wastes at the Savannah River Plant will be completely converted by about 2010. 21 figures.

Maher, R; Shafranek, L F; Stevens, III, W R

1983-01-01

423

Management of high-level waste repository siting.  

PubMed

The selection of sites to store high-level radioactive waste will require more than technical decisions; an acceptable site must gain widespread public support. Ad hoc approaches have recently served as a stimulus to overcome institutional inertia in radioactive waste management, as exemplified by the Interagency Review Group and the State Planning Council for Radioactive Waste Management, but ad hoc approaches have not characteristically succeeded in resolving intense conflicts. Acceptable sites can best be established through traditional processes of legal and scientific advocacy, and their ultimate legitimacy will depend on the proper use of established democratic processes. PMID:17807127

Hill, D; Pierce, B L; Metz, W C; Rowe, M D; Haefele, E T; Bryant, F C; Tuthill, E J

1982-11-26

424

Corrosion and failure processes in high-level waste tanks  

SciTech Connect

A large amount of radioactive waste has been stored safely at the Savannah River and Hanford sites over the past 46 years. The aim of this report is to review the experimental corrosion studies at Savannah River and Hanford with the intention of identifying the types and rates of corrosion encountered and indicate how these data contribute to tank failure predictions. The compositions of the High-Level Wastes, mild steels used in the construction of the waste tanks and degradation-modes particularly stress corrosion cracking and pitting are discussed. Current concerns at the Hanford Site are highlighted.

Mahidhara, R.K.; Elleman, T.S.; Murty, K.L. [North Carolina State Univ., Raleigh, NC (United States)

1992-11-01

425

High-level neutron coincidence counter maintenance manual  

SciTech Connect

High-level neutron coincidence counter operational (field) calibration and usage is well known. This manual makes explicit basic (shop) check-out, calibration, and testing of new units and is a guide for repair of failed in-service units. Operational criteria for the major electronic functions are detailed, as are adjustments and calibration procedures, and recurrent mechanical/electromechanical problems are addressed. Some system tests are included for quality assurance. Data on nonstandard large-scale integrated (circuit) components and a schematic set are also included.

Swansen, J.; Collinsworth, P.

1983-05-01

426

HIGH LEVELS OF URANIUM IN GROUNDWATER OF ULAANBAATAR, MONGOLIA  

PubMed Central

Water samples collected from 129 wells in seven of the nine sub-divisions of Ulaanbaatar were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) using Clean Lab methods. The levels of many trace elements were found to be very low with the average concentrations (ranges in brackets) being 0.9 (<0.1-7.9) ?g/L for As; 7.7 (0.12-177) ?g/L for Mn; 0.2 (<0.05-1.9) ?g/L for Co; 16 (<0.1-686) ?g/L for Zn; 0.7 (<0.1-1.8) ?g/L for Se; <0.1 (<0.02-0.69) ?g/L for Cd; and 1.3 (<0.02-32) ?g/L for Pb. The levels of uranium were surprisingly elevated (mean, 4.6 ?g/L; range <0.01-57 ?g/L, with the values for many samples exceeding the World Health Organization's guideline of 15 ?g/L for uranium in drinking water. Local rocks and soils appear to be the natural source of the uranium. The levels of uranium in Ulaanbaatar's groundwater are in the range that has been associated with nephrotoxicity, high blood pressure, bone dysfunction and likely reproductive impairment in human populations. We consider the risk associated with drinking the groundwater with elevated levels of uranium in Ulaanbaatar to be a matter for some public health concern and conclude that the paucity of data on chronic effects of low level exposure is a risk factor for continuing the injury to many people in this city.

Nriagu, Jerome; Nam, Dong-Ha; Ayanwola, Titilayo A.; Dinh, Hau; Erdenechimeg, Erdenebayar; Ochir, Chimedsuren; Bolormaa, Tsend-Ayush

2011-01-01

427

Abnormally high serum ferritin levels among professional road cyclists  

PubMed Central

Background: An international, longitudinal medical follow up examination of male professional road cyclists revealed excessively elevated serum ferritin levels. Objective: To evaluate the importance of elevated ferritin values among professional cyclists, their relationship with age and nationality, and their evolution over 3 years. Methods: Over 1000 serum ferritin values were collected. Other parameters were included in order to exclude conditions which might have increased ferritin levels without changing body iron stores. Results: In 1999, over 45% of riders displayed ferritin values above 300 ng/ml and one fourth levels over 500 ng/ml. These percentages had decreased to 27% and 9%, respectively, 3 years later, while the overall average, which was above the normal limits in 1999, had decreased by 33% in 3 years. Older cyclists had higher ferritin values than younger cyclists. There was also a relationship between ferritin levels and the nationality of the cyclists. Analysis of 714 riders in 2000 and 2002 showed only a slight and insignificant decrease in the mean ferritin value although those with initially elevated iron stores had a much greater decrease. Conclusion: Professional road cyclists used excessive iron supplementation leading to high serum ferritin levels correlating with increased body iron stores. Although the situation progressively improved over 3 years, it remains worrying as increased body iron stores are related to health complications. Therefore, prevention in addition to the fight against doping should be a main goal of the UCI. Aggressive therapy for athletes with excessive ferritin values should be carried out at or before the end of their careers.

Zotter, H; Robinson, N; Zorzoli, M; Schattenberg, L; Saugy, M; Mangin, P

2004-01-01

428

Gravity Probe B  

NSDL National Science Digital Library

This broadcast reports on Gravity Probe B, a satellite designed to test the frame dragging prediction of Einstein's theory of general relativity, where a spinning object such as the Earth will push spacetime in front of it. Gravity Probe B uses gyroscopes which will shift direction while orbiting the Earth (if general relativity is correct). The broadcast contains comments from a scientist who has worked on the Gravity Probe B mission for over 44 years. There is a brief explanation of the difference between the behavior of gravity in Newtonian physics and general relativity. The broadcast also discusses why it took so long to build the satellite (a dozen technologies had to be invented first), the cost involved, and whether the plug would be pulled on the mission; however, Gravity Probe B was finally launched on April 20, 2004. The broadcast is 30 minutes in length.

429

Linearization of the Fermilab recycler high level RF  

SciTech Connect

In studying the Recycler high level RF, it was found that at 89 kHz, the lowest frequency required by the system, some nonlinearities in magnitude and phase were discovered. The visible evidence of this was that beam injected in a barrier bucket had a definite slope at the top. Using a network analyzer, the S-parameter S{sub 21} was realized for the overall system and from mathematical modeling a second order numerator and denominator transfer function was found. The inverse of this transfer function gives their linearization transfer function. The linearization transfer function was realized in hardware by summing a high pass, band pass and low pass filter together. The resulting magnitude and phase plots, along with actual beam response will be shown.

Joseph E Dey; Tom Kubicki; John Reid

2003-05-28

430

Remote ignitability analysis of high-level radioactive waste  

SciTech Connect

The Idaho Chemical Processing Plant (ICPP), was used to reprocess nuclear fuel from government owned reactors to recover the unused uranium-235. These processes generated highly radioactive liquid wastes which are stored in large underground tanks prior to being calcined into a granular solid. The Resource Conservation and Recovery Act (RCRA) and state/federal clean air statutes require waste characterization of these high level radioactive wastes for regulatory permitting and waste treatment purposes. The determination of the characteristic of ignitability is part of the required analyses prior to calcination and waste treatment. To perform this analysis in a radiologically safe manner, a remoted instrument was needed. The remote ignitability Method and Instrument will meet the 60 deg. C. requirement as prescribed for the ignitability in method 1020 of SW-846. The method for remote use will be equivalent to method 1020 of SW-846.

Lundholm, C.W.; Morgan, J.M.; Shurtliff, R.M.; Trejo, L.E.

1992-09-01

431

Separation processes for high-level radioactive waste treatment  

SciTech Connect

During World War II, production of nuclear materials in the United States for national defense, high-level waste (HLW) was generated as a byproduct. Since that time, further quantities of HLW radionuclides have been generated by continued nuclear materials production, research, and the commercial nuclear power program. In this paper HLW is defined as the highly radioactive material resulting from the processing of spent nuclear fuel. The HLW is the liquid waste generated during the recovery of uranium and plutonium in a fuel processing plant that generally contains more than 99% of the nonvolatile fission products produced during reactor operation. Since this paper deals with waste separation processes, spent reactor fuel elements that have not been dissolved and further processed are excluded.

Sutherland, D.G.

1992-11-01

432

High-level waste melter alternatives assessment report  

SciTech Connect

This document describes the Tank Waste Remediation System (TWRS) High-Level Waste (HLW) Program`s (hereafter referred to as HLW Program) Melter Candidate Assessment Activity performed in fiscal year (FY) 1994. The mission of the TWRS Program is to store, treat, and immobilize highly radioactive Hanford Site waste (current and future tank waste and encapsulated strontium and cesium isotopic sources) in an environmentally sound, safe, and cost-effective manner. The goal of the HLW Program is to immobilize the HLW fraction of pretreated tank waste into a vitrified product suitable for interim onsite storage and eventual offsite disposal at a geologic repository. Preparation of the encapsulated strontium and cesium isotopic sources for final disposal is also included in the HLW Program. As a result of trade studies performed in 1992 and 1993, processes planned for pretreatment of tank wastes were modified substantially because of increasing estimates of the quantity of high-level and transuranic tank waste remaining after pretreatment. This resulted in substantial increases in needed vitrification plant capacity compared to the capacity of original Hanford Waste Vitrification Plant (HWVP). The required capacity has not been finalized, but is expected to be four to eight times that of the HWVP design. The increased capacity requirements for the HLW vitrification plant`s melter prompted the assessment of candidate high-capacity HLW melter technologies to determine the most viable candidates and the required development and testing (D and T) focus required to select the Hanford Site HLW vitrification plant melter system. An assessment process was developed in early 1994. This document describes the assessment team, roles of team members, the phased assessment process and results, resulting recommendations, and the implementation strategy.

Calmus, R.B.

1995-02-01

433

Comparison of marine gravity from shipboard and high-density satellite altimetry along the Mid-Atlantic Ridge, 30.5°-35.5°S  

NASA Astrophysics Data System (ADS)

We compare new marine gravity fields derived from satellite altimetry with shipboard measurements over a region of more than 120,000 square kilometers in the central South Atlantic. Newly declassified satellite data were employed to construct free-air anomaly maps on 0.05 degree grids [Sandwell and Smith, 1992; Marks et al., 1993]. An extensive gravity and bathymetry dataset from four cruises along the Mid-Atlantic Ridge from 30.5-35.5°S provides a benchmark for testing the two-dimensional resolution and accuracy of the satellite measurements where their crosstrack spacing is near their widest. The satellite gravity signal is coherent with bathymetry in this region down to wavelengths of 26 km (?²=0.5), compared to 12.5 km for shipboard gravity. Residuals between the shipboard and satellite datasets have a roughly normal distribution. The standard deviation of satellite gravity with respect to shipboard measurements is nearly 7 mGal in a region of 140 mGal total variation, whereas the internal standard deviation at crossovers for GPS-navigated shipboard data is 1.8 mGal. The differences between shipboard and satellite data are too large to use satellite gravity to determine crustal thickness variations within a typical ridge segment.

Neumann, Gregory A.; Forsyth, Donald W.; Sandwell, David

1993-08-01

434

f(R) theories of gravity  

Microsoft Academic Search

Modified gravity theories have received increased attention lately due to combined motivation coming from high-energy physics, cosmology, and astrophysics. Among numerous alternatives to Einstein's theory of gravity, theories that include higher-order curvature invariants, and specifically the particular class of f(R) theories, have a long history. In the last five years there has been a new stimulus for their study, leading

Thomas P. Sotiriou; Valerio Faraoni

2010-01-01

435

LUNAR GRAVITY: A MASS POINT MODEL  

Microsoft Academic Search

A point mass representation of a tion, 1976) shows consistency for each of the quasi-global gravity field of the moon is devel- second- and third-degree harmonic coefficients. oped by processing Apollo 15 and 16 subsatellite However, higher-degree terms show little consis- and Lunar Orbiter 5 Doppler tracking data. The tency. High-degree harmonic gravity fields deter- model is generated by reducing

Mohan P. Ananda

1977-01-01

436

The CMS High Level Trigger System: Experience and Future Development  

NASA Astrophysics Data System (ADS)

The CMS experiment at the LHC features a two-level trigger system. Events accepted by the first level trigger, at a maximum rate of 100 kHz, are read out by the Data Acquisition system (DAQ), and subsequently assembled in memory in a farm of computers running a software high-level trigger (HLT), which selects interesting events for offline storage and analysis at a rate of order few hundred Hz. The HLT algorithms consist of sequences of offline-style reconstruction and filtering modules, executed on a farm of 0(10000) CPU cores built from commodity hardware. Experience from the operation of the HLT system in the collider run 2010/2011 is reported. The current architecture of the CMS HLT, its integration with the CMS reconstruction framework and the CMS DAQ, are discussed in the light of future development. The possible short- and medium-term evolution of the HLT software infrastructure to support extensions of the HLT computing power, and to address remaining performance and maintenance issues, are discussed.

Bauer, G.; Behrens, U.; Bowen, M.; Branson, J.; Bukowiec, S.; Cittolin, S.; Coarasa, J. A.; Deldicque, C.; Dobson, M.; Dupont, A.; Erhan, S.; Flossdorf, A.; Gigi, D.; Glege, F.; Gomez-Reino, R.; Hartl, C.; Hegeman, J.; Holzner, A.; Hwong, Y. L.; Masetti, L.; Meijers, F.; Meschi, E.; Mommsen, R. K.; O'Dell, V.; Orsini, L.; Paus, C.; Petrucci, A.; Pieri, M.; Polese, G.; Racz, A.; Raginel, O.; Sakulin, H.; Sani, M.; Schwick, C.; Shpakov, D.; Simon, S.; Spataru, A. C.; Sumorok, K.

2012-12-01

437

Long-term high-level waste technology. Composite report  

NASA Astrophysics Data System (ADS)

Research and development studies on the immobilization of high-level wastes from the chemical reprocessing of nuclear reactor fuels are summarized. The reports are grouped under the following tasks: (1) program management and support; (2) waste preparation; (3) waste fixation; and (4) final handling. Some of the highlights are: leaching properties were obtained for titanate and tailored ceramic materials being developed at ICPP to immobilize zirconia calcine; comparative leach tests, hot-cell tests, and process evaluations were conducted of waste form alternatives to borosilicate glass for the immobilization of SRP high-level wastes, experiments were run at ANL to qualify neutron activation analysis and radioactive tracers for measuring leach rates from simulated waste glasses; comparative leach test samples of SYNROC D were prepared, characterized, and tested at LLNL; encapsulation of glass marbles with lead or lead alloys was demonstrated on an engineering scale at PNL; a canister for reference Commercial HLW was designed at PNL; a study of the optimization of salt-crete was completed at SRL; a risk assessment showed that an investment for tornado dampers in the interim storage building of the DWPF is unjustified.

Cornman, W. R.

1981-12-01

438

Spent Fuel and High-Level Radioactive Waste Transportation Report  

SciTech Connect

This publication is intended to provide its readers with an introduction to the issues surrounding the subject of transportation of spent nuclear fuel and high-level radioactive waste, especially as those issues impact the southern region of the United States. It was originally issued by SSEB in July 1987 as the Spent Nuclear Fuel and High-Level Radioactive Waste Transportation Primer, a document patterned on work performed by the Western Interstate Energy Board and designed as a ``comprehensive overview of the issues.`` This work differs from that earlier effort in that it is designed for the educated layman with little or no background in nuclear waste Issues. In addition. this document is not a comprehensive examination of nuclear waste issues but should instead serve as a general introduction to the subject. Owing to changes in the nuclear waste management system, program activities by the US Department of Energy and other federal agencies and developing technologies, much of this information is dated quickly. While this report uses the most recent data available, readers should keep in mind that some of the material is subject to rapid change. SSEB plans periodic updates in the future to account for changes in the program. Replacement pages will be supplied to all parties in receipt of this publication provided they remain on the SSEB mailing list.

Not Available

1992-03-01

439

System performance of high-level waste package components  

SciTech Connect

This report presents analytical and experimental studies that describe the performance of nuclear waste packages at the system level. Several water chemistry modules were developed, and ground-water-radiolysis studies were performed to examine the production of radiolytic species at the outside surface of waste packages. Uncertainty analysis studies with a UO/sub 2/ water chemistry model assessed the importance of input parameters on the variability of calculated solubilities. A shell for a computer code was developed that provides an alternative method for examining the system performance of high-level waste packages. Integral experiments were conducted to examine interactions between components of the waste package and repository, bringing together elements of repository environments with components of spent-fuel waste forms. The system performance investigations showed that radiolysis effects are not significant when the gamma source is shielded by the overpack. The production of oxalate is related to bicarbonate concentration and dose rate. The dissolution of UO/sub 2/ may be influenced significantly by solution pe and chloride concentration. Spent fuel performance studies showed that spent fuel rod sections with microscopic failure openings showed unexpected high release rates for some radionuclides when compared with releases from macroscopic failure openings. 121 refs., 81 figs., 30 tabs.

Nicolosi, S.L.; Kurth, R.E.; Quayle, S.F.; Hess, D.J.; Markworth, A.J.

1987-09-01

440

VITRIFICATION OF HIGH LEVEL WASTE AT THE SAVANNAH RIVER SITE  

SciTech Connect

The objective of this study was to experimentally measure the properties and performance of a series of glasses with compositions that could represent high level waste Sludge Batch 5 (SB5) as vitrified at the Savannah River Site Defense Waste Processing Facility. These data were used to guide frit optimization efforts as the SB5 composition was finalized. Glass compositions for this study were developed by combining a series of SB5 composition projections with a group of candidate frits. The study glasses were fabricated using depleted uranium and their chemical compositions, crystalline contents and chemical durabilities were characterized. Trevorite was the only crystalline phase that was identified in a few of the study glasses after slow cooling, and is not of concern as spinels have been shown to have little impact on the durability of high level waste glasses. Chemical durability was quantified using the Product Consistency Test (PCT). All of the glasses had very acceptable durability performance. The results of this study indicate that a frit composition can be identified that will provide a processable and durable glass when combined with SB5.

Fox, K.; Peeler, D.

2009-06-17

441

Characterization of high-level quinolone resistance in Campylobacter jejuni.  

PubMed Central

High-level resistance to quinolones has previously been shown to occur in Campylobacter spp. both in vitro and in patients treated with quinolones. We have selected isolates that are resistant to quinolones by plating cells from a susceptible C. jejuni strain, UA535, on medium containing nalidixic acid at 32 micrograms/ml. Fluctuation analysis indicated that resistance occurred by mutation at a frequency of 5 x 10(-8) per cell plated. Unlike what is observed with other gram-negative organisms, the nalidixic acid-resistant mutants demonstrated high-level cross-resistance (MIC, greater than or equal to 4 micrograms/ml) to newer quinolones, including ciprofloxacin, norfloxacin, and temafloxacin, yet remained susceptible to coumermycin A1 and several other unrelated antibiotics. Mutants with an identical resistance phenotype could also be selected from UA535 with ciprofloxacin and norfloxacin at a similar frequency. To study the mechanism of quinolone resistance, DNA gyrases were purified from C. jejuni UA535 and two resistant mutants by heparin-agarose and novobiocin-Sepharose chromatography. After the respective enzyme concentrations were adjusted to equivalent units of a