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1

Dual shell pressure balanced vessel  

Energy Technology Data Exchange (ETDEWEB)

A dual-wall pressure balanced vessel for processing high viscosity slurries at high temperatures and pressures having an outer pressure vessel and an inner vessel with an annular space between the vessels pressurized at a pressure slightly less than or equivalent to the pressure within the inner vessel.

Fassbender, Alexander G. (West Richland, WA)

1992-01-01

2

Earth Pressure on Tunnel Crown  

DEFF Research Database (Denmark)

Two different analyses have been carried out in order to find the vertical earth pressure, or overburden pressure, at the crown of a tunnel going through a dike. Firstly, a hand calculation is performed using a simple dispersion of the stresses over depth. Secondly, the finite?element program Plaxis is utilized to check the result.

Andersen, Lars

2008-01-01

3

Modeling of the Earth’s Planetary Heat Balance with Electrical Circuit Analogy  

Directory of Open Access Journals (Sweden)

Full Text Available The integral heat model for the system of the Earth’s surface—the atmosphere—the open space based on the electrical circuit analogy is presented. Mathematical models of the heat balance for this system are proposed. Heat circuit which is analog of the electrical circuit for investigating the temperature dependencies on the key parameters in the clear form is presented.

Habibullo I. Abdussamatov; Alexander I. Bogoyavlenskii; Sergey I. Khankov; Yevgeniy V. Lapovok

2010-01-01

4

Seismic induced earth pressures in buried vaults  

International Nuclear Information System (INIS)

The magnitude and distribution of earth pressures acting on buried structures and induced by a seismic event are considered in this paper. A soil-structure-interaction analysis is performed for typical Department of Energy high level waste storage tanks using a lumped parameter model. The resulting soil pressure distributions are determined and compared with the static soil pressure to assess the design significance of the seismic induced soil pressures. It is found that seismic pressures do not control design unless the peak ground acceleration exceeds about 0.3 G. The effect of soil non linearities (resulting from local soil failure) are also found to have little effect on the predictions of the seismic response of the buried structure. The seismic induced pressures are found to be very similar to those predicted using the elastic model in ASCE 4-86.

1994-01-01

5

Earth in the balance. Ecology and the human spirit  

International Nuclear Information System (INIS)

This book is the translation of the original American edition ''earth in the balance''. When Earth in the Balance first came out, it caused quite a stir and for good reason. It convincingly makes the case that a crisis of epidemic proportions is nearly upon us and that if the world does not get its act together soon and agree to some kind of 'Global Marshall Plan' to protect the environment, we're all up a polluted creek without a paddle. Myriad plagues are upon us, but the worst include the loss of biodiversity, the depletion of the ozone layer, the slash-and-burn destruction of rain forests, and the onset of global warming. None of this is new, of course, nor was it new in 1992. But most environmentalists will still get a giddy feeling reading such a call to action as written by a prominent politician. The book is arranged into three sections: the first describes the plagues; the second looks at how we got ourselves into this mess; and the final chapters present ways out. Gore gets his points across in a serviceable way, though he could have benefited from a firmer editor's hand; at times the analogies are arcane and the pacing is odd kind of like a Gore speech that climaxes at weird points and then sinks just as the audience is about to clap. Still, at the end you understand what's been said. Gore believes that if we apply some American ingenuity, the twin engines of democracy and capitalism can be rigged to help us stabilize world population growth, spread social justice, boost education levels, create environmentally appropriate technologies, and negotiate international agreements to bring us back from the brink. For example, a worldwide shift to clean, renewable energy sources would create huge economic opportunities for companies large and small to design, build, and maintain solar panels, wind turbines, fuel cells, and other eco friendly innovations

2007-01-01

6

Balanced-pressure techniques applied to geothermal drilling  

Energy Technology Data Exchange (ETDEWEB)

Geothermal drilling often takes place in high surface relief areas where ground water tables are a considerable distance (approx. 1000 ft) below rig level. Above the water table, the formation pressure gradient is zero, and below the water table, the formation pressure increases with depth. Pressure unbalance between wellbore drilling fluid and formation pressures exists from spud-in and drives drilling fluid into the formation when voids are encountered at the drill bit. When this happens, drilling fluid does not return to the rig because it is pumped into these voids and thus circulation of the drilling fluid is lost. Lost circulation is generally controlled by two techniques: (1) sealing formations so that drilling fluid will not flow into them; and (2) reducing drilling fluid pressure in the wellbore so that it essentially balances formation fluid pressure. This paper deals with the second control technique, describing four balanced pressure drilling techniques and giving advantages and disadvantages of each.

Dareing, D.W.; Kelsey, J.R.

1981-01-01

7

Journey to the Center of the Earth: Exploring High Pressure  

Energy Technology Data Exchange (ETDEWEB)

The deeper we go into the Earth, the higher the pressure. At the pressures found within the center of our planet, minerals do not simply compress. Pressure dramatically alters all materials properties, in the process creating numerous novel phases not found on the surface. This lecture will describe how we simulate the conditions found in planetary interiors in the lab, what kinds of new behavior we find, and how these observations can explain what is going on within the Earth. High pressure explorations also lead to discoveries of novel materials with potential for practical applications in our low-pressure, environment.

Mao, Wendy

2009-09-29

8

Pressure balanced drag turbine mass flow meter  

Energy Technology Data Exchange (ETDEWEB)

The density of the fluid flowing through a tubular member may be measured by a device comprising a rotor assembly suspended within the tubular member, a fluid bearing medium for the rotor assembly shaft, independent fluid flow lines to each bearing chamber, and a scheme for detection of any difference between the upstream and downstream bearing fluid pressures. The rotor assembly reacts to fluid flow both by rotation and axial displacement; therefore concurrent measurements may be made of the velocity of blade rotation and also bearing pressure changes, where the pressure changes may be equated to the fluid momentum flux imparted to the rotor blades. From these parameters the flow velocity and density of the fluid may be deduced.

Dacus, Michael W. (Gilbert, AR); Cole, Jack H. (Fayetteville, AR)

1982-01-01

9

Performance of earth pressure cell as grain pressure transducer in a model silo  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Numerous methods have been proposed for determining the pressure exerted by grain at discrete locations in a storage structure, but few satisfactory solutions have been found. Earth pressure cells were tested as potential measurement devices for grain bins. Earth pressure cells are commercial transd...

M. Molenda; M.D. Montross; J. Horabik

10

Low-temperature hydrogen circulation system of the pressure balance  

International Nuclear Information System (INIS)

[en] In China Spallation Neutron Source (CSNS), which is under construction recently in Southern China, a cryogenic system is used to cool down the neutron moderator. Pressure control system is a key unit to balance the pressure in H2 loop. Denisty of H2 in loop is almost constant under the design condition of 18-21K. When temperature change 1K, large variation pressure about 1 MPa change in H2 loop. By analysis three pressure control modes of warm buffer, cryogenic dewar and accumulator, pressure fluctuation can be controlled by accumulator more perfectly with less hydrogen inventory in H2 loop. (authors)

2010-01-01

11

Pressure balanced bearing assembly for downhole motors  

Energy Technology Data Exchange (ETDEWEB)

A bearing assembly is described for assembly on a fluid-operated downhole motor on the fluid outlet end comprising a tubular housing having an inlet and an outlet for flow of fluid there through, a stator supported in a fixed position in the housing, a rotor supported for rotary movement in the stator. The assembly comprises a bearing housing adapted to be removably secured on the outlet end of the motor housing; a shaft for supporting a drill bit and adapted to be connected to the rotor and supported for rotary movement in the bearing housing; the housing being operable to receive drilling fluid under pressure flowing from the motor for discharge there through into the borehole; and bearing means cooperable with the shaft and the bearing housing to carry a longitudinally downward thrust load of the shaft.

Maurer, W.C.; Mc Donald, W.J.

1987-05-19

12

Rational evaluation method of earth pressure on the cantilever retaining wall; Kakato bantsuki yoheki no goritekina doatsu hyokaho  

Energy Technology Data Exchange (ETDEWEB)

In the designing of a heel plate-provided retaining wall, the currently-used earth pressure assessment method fails to reasonably assess the effect of the raising fill shape and heel plate length. To remedy the drawback, in this paper, a new earth pressure assessment method based on the infinitesimal balancing method is proposed, and formulated, and the effectiveness of the new method is verified by a laboratory model test and trial calculation. On the assumption of two linear sliding surfaces running forward and backward from the rear edge of a heel plate, an infinitesimal balancing equation is built for the wedge-shape lump formed by the two sliding surfaces, and this can formularize the earth pressure problem. The major earth pressure resultant PA working on the virtual wall and its angle of inclination {delta} can be determined by finding out sliding angles {omega}1 and {omega}2 that maximize PAcos{delta}. That is to say, the major earth pressure and its angle of inclination may be theoretically determined without assuming {delta} as in the earth pressure assessment method now in use. 22 refs., 25 figs., 1 tab.

Ushiro, T.; Tsutsui, H.; Yagi, N.; Yatabe, R. [Ehime University, Ehime (Japan). Faculty of Engineering

1997-06-20

13

Assessment of plantar pressure and balance in patients with diabetes.  

UK PubMed Central (United Kingdom)

INTRODUCTION: Patients with diabetes for more than 10 years may have an increase in peak plantar pressure, considerable postural oscillation, balance deficit, alterations in gait pattern and an increased risk of falls. The aim of the present study was to assess the correlation between plantar pressure distribution and balance in patients with diabetes using a pressure platform (Footwork). MATERIAL AND METHODS: The study was carried out at the Human Movement Clinic of the Centro Universitário de Belo Horizonte (Brazil). The sample was made up of 18 right-handed individuals with type 2 diabetes - 14 females and 4 males - with an average age of 58.72 ±9.54 and an average of 18.56 ±6.61 years since diagnosis. RESULT: Data analysis revealed that greater peak plantar pressure on the right hindfoot led to greater radial displacement (Rd) (r = 0.2022) and greater displacement velocity (r = 0.2240). Greater peak plantar pressure on the left hindfoot also led to greater displacement velocity (P) (r = 0.5728) and radial displacement (RD) (r = 0.1972). A positive correlation was found between time elapsed since diagnosis and peak midfoot pressure (r = 0.3752) on the right and left side as well as between BMI and plantar pressure on all regions of the foot. CONCLUSIONS: The data reveal a correlation between postural oscillation and peak plantar pressure on the hindfoot.

Anjos DM; Gomes LP; Sampaio LM; Correa JC; Oliveira CS

2010-03-01

14

Characteristics of the ion pressure tensor in the Earth`s magnetosheath: AMPTE/IRM observations  

Energy Technology Data Exchange (ETDEWEB)

AMPTE/IRM satellite data are used to examine characteristics of the ion pressure tensor in the Earth`s magnetosheath. The eigenvalues and principal axes of the pressure tensor are computed, and the directions of the principal axes are compared to the direction of the independently measured magnetic field B. When the pressure tensor is anisotropic, as is usually the case in the magnetosheath, one of its eigenvalues is observed to be distinguishable from the other two, which are about equal to one another. The eigenvector associated with the distinguishable eigenvalue is an axis of symmetry of the pressure tensor. This symmetry axis is generally not parallel to B. New features of the plasma distribution function are revealed by using the actual eigenvalues of the pressure tensors rather than the usual p(perpendicular) and p(parallel) where perpendicular and parallel denote directions to B.

Lewis, H.R.; Li, X.; Phan, T.D.; Treumann, R.A. [Herzberg Inst. of Astrophysics, Ottawa, Ontario (Canada)]|[Max-Planck-Inst. fuer Extraterrestrische Physik, Garching (Germany)

1994-01-01

15

Physical Limitations of Empirical Field Models: Force Balance and Plasma Pressure  

International Nuclear Information System (INIS)

[en] In this paper, we study whether the magnetic field of the T96 empirical model can be in force balance with an isotropic plasma pressure distribution. Using the field of T96, we obtain values for the pressure P by solving a Poisson-type equation (gradient)2P = (gradient) · (J x B) in the equatorial plane, and 1-D profiles on the Sun-Earth axis by integrating (gradient)P = J x B. We work in a flux coordinate system in which the magnetic field is expressed in terms of Euler potentials. Our results lead to the conclusion that the T96 model field cannot be in equilibrium with an isotropic pressure. We also analyze in detail the computation of Birkeland currents using the Vasyliunas relation and the T96 field, which yields unphysical results, again indicating the lack of force balance in the empirical model. The underlying reason for the force imbalance is likely the fact that the derivatives of the least-square fitted model B are not accurate predictions of the actual magnetospheric field derivatives. Finally, we discuss a possible solution to the problem of lack of force balance in empirical field models

2002-01-01

16

Physical Limitations of Empirical Field Models: Force Balance and Plasma Pressure  

Energy Technology Data Exchange (ETDEWEB)

In this paper, we study whether the magnetic field of the T96 empirical model can be in force balance with an isotropic plasma pressure distribution. Using the field of T96, we obtain values for the pressure P by solving a Poisson-type equation {del}{sup 2}P = {del} {center_dot} (J x B) in the equatorial plane, and 1-D profiles on the Sun-Earth axis by integrating {del}P = J x B. We work in a flux coordinate system in which the magnetic field is expressed in terms of Euler potentials. Our results lead to the conclusion that the T96 model field cannot be in equilibrium with an isotropic pressure. We also analyze in detail the computation of Birkeland currents using the Vasyliunas relation and the T96 field, which yields unphysical results, again indicating the lack of force balance in the empirical model. The underlying reason for the force imbalance is likely the fact that the derivatives of the least-square fitted model B are not accurate predictions of the actual magnetospheric field derivatives. Finally, we discuss a possible solution to the problem of lack of force balance in empirical field models.

Sorin Zaharia; C.Z. Cheng

2002-06-18

17

Reliability of Center of Pressure Measures During Dynamic Balance Performance  

Directory of Open Access Journals (Sweden)

Full Text Available Background and Aim: Few studies have assessed the reliability of postural balance measures during dynamic balance performance that introduce additional challenging to postural control system. In addition sometimes in the static conditions some deficiencies of the postural control system may not be revealed obviously therefore the aim of this study was to assess the reliability of postural control parameters during functional performance on force plate in healthy subjects.Materials and Methods: Ten healthy male subjects (mean age: 25.4 years, weight: 68.2 kg height:176.9cm) participated in this study. None of the subjects were involved in sport activities. Every subject performed three 15seconds trials of eyes open single leg stance on a force plate during dynamic balance task. Participants grasped object with hand at their waist level and release it at above shoulder level. The reproducibility of the center of pressure (COP) deviations (average speed &length of path) was assessed. All participants were tested on 2 sessions with an inter-measurement interval of 7 days. COP data was collected for each trial. The intraclass correlation coefficient (ICC) was used as parameter of intra-session and inter-session (Test-Retest) reliability.Results: The ICCs for intra-session reliability of average speed and length of COP path were 0.89 and 0.91 respectively. The ICCs for inter-session reliability were 0.95 and 0.96 respectively.Conclusion: The study showed high and very high reliability for center of pressure measures during dynamic balance task. Therefore this dynamic performance can be used as a balance pattern in postural control assessment. These can be used as reliable parameters in dynamic postural control assessment due to high reliability of average speed and length of COP path.

Seye Hamed Fazeli; Ali Amiry; Ali Ashraf Jamshidi; Mohammad Ali Sanjary

2011-01-01

18

Performance of earth pressure cell as grain pressure transducer in a model silo  

Directory of Open Access Journals (Sweden)

Full Text Available Numerous methods have been proposed for determining the pressure exerted by grain at discrete locations in a storage structure, but few satisfactory solutions have been found. Earth pressure cells were tested as potential measurement devices for grain bins. Earth pressure cells are commercial transducers designed for geotechnical applications. Calibration of the earth pressure cell was performed in a pressurized chamber filled with wheat under normal load as well as shear load. The cell was tested in a model grain silo 1.83 m in diameter d with a height hc of 5.75 m. Vertical floor pressures and horizontal wall pressures were measured at different points in the model bin. The vertical floor pressure pvi was measured at two different radial locations and horizontal wall pressure ph was measured at four different wall heights. The vertical floor pressure obtained using the earth pressure cell was in good agreement with the mean floor pressure pv calculated using load cells that supported the entire floor or the bin. Considerable variation in the vertical floor pressure along the silo floor radius was observed. The variation of the lateral-to-vertical pressure ratio, K, was monitored during each fill-unload cycle of the model silo. In the case of the maximum h/d ratio of 2, K increased during filling and stabilized after reaching a grain h/d ratio of 1.3. At the onset of discharge, the pressure ratio immediately increased up to value of approximately 0.7, and remained stable during unloading down to a h/d ratio of approximately 0.65 when K decreased rapidly.

M. Molenda; M.D. Montross; J. Horabik

2007-01-01

19

New weight-handling device for commercial oil pressure balances  

Science.gov (United States)

This paper presents a new device to automatically handle a large number of weights for the calibration of a pressure gauge. This newly invented weight-handling device is made for use in conjunction with a commercial oil pressure balance. Although the pressure balance is essential as a calibration tool, its use has been generally tedious and labour intensive for a long time. In particular, the process of loading a different combination of weights on the top of a piston requires repetitious manual handling for every new measurement. This inevitably leaves the operator fatigued, and sometimes causes damage to the weights due to careless handling. The newly invented automatic weight-handling device can eliminate such tedious, error-prone and wear-inducing manual weight manipulation. The device consists of a stepping motor, a drive belt, a solenoid valve, three weight-lifting assemblies and three linear-motion guide assemblies. The weight-lifting assembly is composed of a pneumatic actuator, a solid-state switch and a metal finger. It has many advantages compared with the commercial automatic weight-handling device. Firstly, it is not necessary to lift all the weights off the piston in the weight selection process, as it is in the case of the commercial device. Thus it can prevent a permanent deformation of the weight carrier. Secondly, this new device can handle a larger number of weights than the commercial one. This is because the new device adopts a different method in retaining the remaining weights in place. Another advantage of this new device is that there is no possibility of the fingers touching the surface of the weights due to the oscillation of weights. Moreover it uses the general technology of a stepping motor, and is also made up of components that are easily obtainable in the market, thereby being very economical.

Woo, S. Y.; Choi, I. M.; Kim, B. S.

2005-12-01

20

Dual shell pressure balanced reactor vessel. Final project report  

International Nuclear Information System (INIS)

The Department of Energy's Office of Energy Research (OER) has previously provided support for the development of several chemical processes, including supercritical water oxidation, liquefaction, and aqueous hazardous waste destruction, where chemical and phase transformations are conducted at high pressure and temperature. These and many other commercial processes require a pressure vessel capable of operating in a corrosive environment where safety and economy are important requirements. Pacific Northwest Laboratory (PNL) engineers have recently developed and patented (U.S. patent 5,167,930 December 1, 1992) a concept for a novel Dual Shell Pressure Balanced Vessel (DSPBV) which could solve a number of these problems. The technology could be immediately useful in continuing commercialization of an R ampersand D 100 award-winning technology, Sludge-to-oil Reactor System (STORS), originally developed through funding by OER. Innotek Corporation is a small business that would be one logical end-user of the DSPBV reactor technology. Innotek is working with several major U.S. engineering firms to evaluate the potential of this technology in the disposal of wastes from sewage treatment plants. PNL entered into a CRADA with Innotek to build a bench-scale demonstration reactor and test the system to advance the economic feasibility of a variety of high pressure chemical processes. Hydrothermal processing of corrosive substances on a large scale can now be made significantly safer and more economical through use of the DSPBV. Hydrothermal chemical reactions such as wet-air oxidation and supercritical water oxidation occur in a highly corrosive environment inside a pressure vessel. Average corrosion rates from 23 to 80 miles per year have been reported by Rice (1994) and Latanision (1993).

1994-01-01

 
 
 
 
21

High Pressure Structural Studies on Rare-Earth Sesquioxides  

Science.gov (United States)

The Rare-Earth sesquioxides (RE2O3) exhibit interesting physical and chemical properties. Some of these oxides have tremendous technological applications. At ambient conditions, the RE2O3 systems exist in three polymorphic forms, namely: hexagonal A- type, monoclinic B- type, and cubic C- type. The structural stability of three RE2O3 systems: RE = Gd, Ho, Tm and the Tb4O7 system have been studied under high pressure. All the four systems exhibited interesting pressure induced phase transitions. Gd2O3 exhibited C-A transition at ~ 12 GPa, whereas Ho2O3 and Tm2O3 exhibited C-B transition at pressures of 9.5 and 7 GPa respectively. Tb4O7 transformed from its cubic fluorite structure to probably the cotunnite phase at a relatively higher pressure of 27 GPa. The unusual large pressure stability of Tb4O7 was attributed to the presence of Tb4+ ions. The bulk moduli show systematic increase with higher cations, probably due to the enhanced influence of the 4f electron states and increased nature of covalency. However, the mechanisms of the structural transitions C-B-A with increased pressure and increased cation radii are yet to be understood.

Sahu, P. Ch; Lonappan, Dayana; Shekar, N. V. Chandra

2012-07-01

22

Gun firing system using fluid filled pressure balance tubing  

Energy Technology Data Exchange (ETDEWEB)

A method of completing a well formed by a well bore having fluid therein intersecting one or more formations of the earth, is described comprising the steps of: providing a perforating gun having a gun firing head associated therewith; forming a fluid chamber above the gun firing head associated with the perforating gun and in fluid communication therewith; filling with fluid the fluid chamber above the gun firing head associated with the perforating gun; running the perforating gun with the fluid chamber formed thereabove into the well bore to a desired location therein adjacent one of the formations therein; compensating for a pressure differential inside the fluid chamber formed above the gun firing head associated with the perforating gun with the pressure of the fluid in the well bore outside of the fluid chamber as the perforating gun is being run into the well bore; transmitting a gun firing force into the chamber to contact the gun firing head associated with the perforating gun thereby perforating the well bore and a portion of one of the formation; and producing fluid from one of the formations into the well bore.

Vann, R.R.; Brieger, E.F.; George, F.R.; Colle, E.A. Jr.; Jones, H.B.

1988-06-07

23

The habitable zone of Earth-like planets with different levels of atmospheric pressure  

CERN Document Server

As a contribution to the study of the habitability of extrasolar planets, we implemented a 1-D Energy Balance Model (EBM), the simplest seasonal model of planetary climate, with new prescriptions for most physical quantities. Here we apply our EBM to investigate the surface habitability of planets with an Earth-like atmospheric composition but different levels of surface pressure. The habitability, defined as the mean fraction of the planet's surface on which liquid water could exist, is estimated from the pressure-dependent liquid water temperature range, taking into account seasonal and latitudinal variations of surface temperature. By running several thousands of EBM simulations we generated a map of the habitable zone (HZ) in the plane of the orbital semi-major axis, a, and surface pressure, p, for planets in circular orbits around a Sun-like star. As pressure increases, the HZ becomes broader, with an increase of 0.25 AU in its radial extent from p=1/3 bar to p=3 bar. At low pressure, the habitability is...

Vladilo, Giovanni; Silva, Laura; Provenzale, Antonello; Ferri, Gaia; Ragazzini, Gregorio

2013-01-01

24

Water-Energy balance in pressure irrigation systems  

Science.gov (United States)

Modernization of irrigation schemes, generally understood as transformation of surface irrigation systems into pressure -sprinkler and trickle- irrigation systems, aims at, among others, improving irrigation efficiency and reduction of operation and maintenance efforts made by the irrigators. Automation techniques become easier after modernization, and operation management plays an important role in energy efficiency issues. Modern systems use to include elevated water reservoirs with enough capacity to irrigate during peak water demand period about 16 to 48 h. However, pressure irrigation systems, in contrast, carry a serious energy cost. Energy requirements depend on decisions taken on management strategies during the operation phase, which are conditioned by previous decisions taken on the design project of the different elements which compose the irrigation system. Most of the countries where irrigation activity is significant bear in mind that modernization irrigation must play a key role in the agricultural infrastructure policies. The objective of this study is to characterize and estimate the mean and variation of the energy consumed by common types of irrigation systems according to their management possibilities. Also is an objective to estimate the fraction of the water reservoirs available along the irrigation campaign for storing the energy from renewable sources during their availability periods. Simulation taking into account all elements comprising the irrigation system has been used to estimate the energy requirements of typical irrigation systems of several crop production systems. The simulation of various types of irrigation systems and management strategies, in the framework imposed by particular cropping systems, would help to develop criteria for improving the energy balance in relation to the irrigation water supply productivity and new opportunities in the renewable energy field.

Sánchez, Raúl; Rodríguez-Sinobas, Leonor; Juana, Luis; Laguna, Francisco V.; Castañón, Guillermo; Gil, María; Benitez, Javier

2013-04-01

25

The Earth's radiation balance and its representation in CMIP5 models  

Science.gov (United States)

The genesis and evolution of Earth's climate is largely regulated by the global energy balance. Despite the central importance of the global energy balance for the climate system and climate change, substantial uncertainties still exist in the quantification of its different components, and its representation in climate models. While the net radiative energy flow in and out of the climate system at the top of atmosphere is known with considerable accuracy from new satellite programs such as CERES, much less is known about the energy distribution within the climate system and at the Earth surface. Accordingly, the quantification of the global energy balance has been controversially disputed in the past. Here we review this discussion and make an attempt to put additional constraints on the components with largest uncertainties. In addition to satellite observations, we thereby make extensive use of the growing number of surface observations to constrain the global energy balance not only from space, but also from the surface. We combine these observations with the latest modeling efforts performed for the 5th IPCC assessment report (CMIP5) to infer best estimates for the global mean surface radiative components. Our analyses favor global mean downward surface solar and thermal radiation values near 185 and 342 Wm-2, respectively, which are most compatible with surface observations. These estimates are lower and higher, respectively, than in many previous assessments, including those presented in previous IPCC reports. It is encouraging that our estimates, which make full use of the information contained in the surface networks, coincide within 2 Wm-2 with the latest satellite-derived estimates (Stephens et al. 2012, Kato et al. submitted to J. Climate), which are completely independently determined. Combining our above estimates with an estimated global mean surface absorbed solar radiation and thermal emission of 161 Wm-2 and 397 Wm-2, respectively, results in 106 Wm-2 of surface net radiation globally available for distribution amongst the non-radiative surface energy balance components. The 23 CMIP5 models investigated in this study overestimate the downward solar and underestimate the downward thermal radiation, both by 5-10 Wm-2 on average. Thus, the CMIP5 models nevertheless simulate an adequate global mean surface net radiation, by error compensation in their downward solar and thermal components. This also suggests that, globally, the simulated surface sensible and latent heat fluxes, around 20 and 85 Wm-2 on average, state realistic values. The findings of this study are compiled into a new global energy balance diagram, and may be able to reconcile currently disputed inconsistencies between global mean energy and water cycle estimates. The study is published online in Climate Dynamics. Related references: Wild, M., 2012: New Directions: A facelift for the picture of the global energy balance. Atmospheric Environment, 55, 366-367. Wild, M., Folini, D., Schär, C., Loeb, N., Dutton, E.G., and König-Langlo, G., 2013: The global energy balance from a surface perspective, Clim. Dyn., published online. Doi:10.1007/s00382-012-1569-8. Stephens, G.L., Li, J.-L., Wild, M., Clayson, C.A., Loeb, N., Kato, S., L'Ecuyer, T., Stackhouse, P.W., and Andrews, T., 2012b: An update on Earth's energy balance in light of the latest global observations, Nature Geoscience, 5, 691-696, doi:10.1038/ngeo1580.

Wild, Martin; Folini, Doris; Schär, Christoph; Loeb, Norman; Dutton, Ellsworth; König-Langlo, Gert

2013-04-01

26

Mass Balance of Polar Ice from Long Wavelength Features of the Earth's Gravitational Field  

Science.gov (United States)

We have used satellite solutions to the low degree zonal harmonics of the Earth''s gravitational potential, and rates of surface accumulation to partially constrain, by means of repeated forward solution, the time rates of thickness change over the Antarctic and Greenland Ice Sheets (dTA and dTG respectively). In addition to the observed zonal coefficients j2 through j5 we impose only one other constraint: That dTA and dTG are proportional to surface accumulation. The lagged response of the Earth to secular changes in ice thickness spanning recent time periods (up to 2000 years before present) and the late Pleistocene is accounted for by means of two viscoelastic rebound models. The sea level contributions from the ice sheets, calculated from dTA and dTG, lower mantle viscosity, and the start time of present-day thickness change are all variables subject to the constraints. For a given set of post glacial rebound inputs, a family of solutions that have similar characteristics and that agree well with observation are obtained from the large number of forward solutions. The off axis position of the Greenland ice sheet makes its contribution to the low degree zonal coefficients less sensitive to the spatial details of the mass balance than to the overall sea level contribution. dTG is therefore modeled as surface mass balance offset by a uniform and constant mass loss. Though dTA varies widely with choices of input parameters, the combined sea level contribution from both ice sheets is reasonably well constrained by the gravity coefficients, and is predicted to range from -0.9 to +1.6 mm yr-1. The sign of the slope of the low degree zonal coefficients versus sea level contribution for Greenland is positive, but for Antarctica, the sign of the slope is positive for even degree and negative for odd degree harmonics. By using this property of the zonal coefficients, it is possible to determine the individual sea level contributions for Greenland and Antarctica. They vary from -0.6 to +0.3 mm yr-1 for the Greenland Ice Sheet, and from -0.3 to +1.3 mm yr-1 for the Antarctic Ice Sheet.

Trupin, Andrew S.; Panfili, Raphael P.

27

The Effect of Displacement Mode of Rigid Retaining Walls on Shearing Bands by Active Earth Pressure  

Directory of Open Access Journals (Sweden)

Full Text Available This work treats the physical modeling of failure mechanisms by active earth pressure. This last is developed by retaining wall movement. A lot of research showed that wall displacement has a significant effect on active earth pressure. A good comprehension of active earth pressure phenomenon and its failure mechanisms help us to better conceive retaining walls. The conception of a small-scale model allowed the realization of active earth pressure tests, while displacing the mobile wall toward the outside of the massif. The studied material is that of Schneebeli; light two-dimensional material made of cylindrical plastic rollers, simulating granular non-cohesive soil. The evolution of shearing zones under continuous and discontinuous displacement modes of mobile walls by correlation pictures allows the investigation of the localization of deformations and failure mechanisms.

A. Sekkel; M. Meghachou

2013-01-01

28

Effect of chemical pressure, misfit strain and hydrostatic pressure on structural and magnetic behaviors of rare-earth orthochromates.  

UK PubMed Central (United Kingdom)

First-principles calculations are performed to investigate structural and magnetic behaviors of rare-earth orthochromates as a function of 'chemical' pressure (that is, the rare-earth ionic radius), epitaxial misfit strain and hydrostatic pressure. From a structural point of view, (i) 'chemical' pressure significantly modifies antipolar displacements, Cr-O-Cr bond angles and the resulting oxygen octahedral tiltings; (ii) hydrostatic pressure mostly changes Cr-O bond lengths; and (iii) misfit strain affects all these quantities. The correlations between magnetic properties (Néel temperature and weak ferromagnetic moments) and unit cell volume are similar when varying the misfit strain or hydrostatic pressure, but differ from those associated with the 'chemical' pressure. Origins of such effects are also discussed.

Zhao HJ; Ren W; Chen XM; Bellaiche L

2013-09-01

29

Influence of cylinder pressure on the balancing of a rotary compressor  

Science.gov (United States)

The investigation presented concerns the balancing procedure of a rotary refrigerant compressor subjected to fairly well-known eccentric masses and to a cylinder pressure force. Particular attention is paid to the influence of pressure force on the response of the compressor. The cylinder pressure force is expanded in a Fourier series for evaluating the bearing characteristics, establishing the balancing and predicting the response of the entire compressor. Rotor dynamics, the finite element and influence coefficient methods are used in order to reduce the vibration levels of the rotor and stator parts of the compressor. The prediction focuses in particular on the orbits at the top and bottom of the housing of an industrial compressor. It demonstrates that cylinder pressure plays a negligible role in the case of the rotary machine presented here, but must be taken into account when high pressure and weak bearing characteristics are combined.

Ferraris, G.; Andrianoely, M.-A.; Berlioz, A.; Dufour, R.

2006-05-01

30

Numerical Simulation of Earth Pressure on Head Chamber of Shield Machine with FEM  

International Nuclear Information System (INIS)

[en] Model parameters of conditioned soils in head chamber of shield machine are determined based on tree-axial compression tests in laboratory. The loads acting on tunneling face are estimated according to static earth pressure principle. Based on Duncan-Chang nonlinear elastic constitutive model, the earth pressures on head chamber of shield machine are simulated in different aperture ratio cases for rotating cutterhead of shield machine. Relationship between pressure transportation factor and aperture ratio of shield machine is proposed by using aggression analysis.

2010-05-21

31

Structure and properties of rare earth silicates with the apatite structure at high pressure  

Science.gov (United States)

The pressure-induced structural transformation of rare earth, non-stoichiometric silicates, (REE9.33(SiO4)6O2, RE = La, Ce, Nd, Eu, and Gd) with the apatite structure type, were investigated by X-ray diffraction, photoluminescence, far-infrared spectroscopy, and DFT calculations. A pressure-induced degradation of symmetry from P6 3 /m to P6 3 occurs with increasing pressure. The transition is due to the tilting of SiO4 tetrahedra and reduced symmetry constraints on one of the O atoms in the tetrahedron. The critical transition pressure increased from ~13 GPa in La9.33(SiO4)6O2 to ~25 GPa in Gd9.33(SiO4)6O2 with the decrease in lanthanide cation size. The high-pressure phase shows an unexpectedly low value for the bulk modulus over a narrow pressure range (below ~30 GPa), as compared with the low-pressure phase, especially for the structure with larger rare earth elements. High-pressure studies of alkaline earth-doped samples (Nd8 A 2(SiO4)6O2 where A = Ca, Sr) showed that the pressure for the phase transition is mainly related to the size of lanthanides that occupy the large channels along the c axis of the apatite structure type.

Zhang, F. X.; Xiao, H. Y.; Lang, M.; Zhang, J. M.; Zhang, Yanwen; Weber, W. J.; Ewing, R. C.

2013-07-01

32

Magnetism in rare earth Co2 compounds under high pressures  

Science.gov (United States)

We have studied electrical resistivity anomalies connected with magnetism in RECo2 (RE=Nd, Tb, Er, Ho) compounds in pressures up to 8 GPa. At ambient pressure the former two compounds exhibit a second order magnetic phase transition (SOMPT) at TC, whereas a first order magnetic phase transition (FOMPT) is observed in the latter two. Although TC decreases with pressure in all four compounds, the TC(P) dependence for NdCo2 and TbCo2 differs considerably from this for HoCo2 and ErCo2. For the latter two, Tc vs P data deviate dramatically from the initial linear dependence above a critical pressure Pc to become almost pressure independent at higher pressures. We propose that this is reflecting the loss of Co metamagnetism that is also indicated by the vanishing resistivity drop at Tc for P>4 GPa and by the change from a FOMPT to a SOMPT. A scenario is discussed assuming that for P>Pc the projected Co 3d density of states at EF decreases. Hence the Co moment collapses because the RE-Co-RE exchange channel becomes ineffective to induce the itinerant 3d electron metamagnetism. The localized RE moments, however, order at a ``residual'' TC due to the persisting Ruderman-Kittel-Kasuya-Yosida-type exchange interaction. For NdCo2 and TbCo2 the Tc values decrease with pressure by an exponential law but remain rather high in the highest applied pressures. Results of first-principles electronic structure calculations using the full-potential linearized augmented plane wave method are presented for HoCo2 and NdCo2 compounds, as well.

Syshchenko, O.; Sechovský, V.; Diviš, M.; Fujita, T.; Hauser, R.; Fujii, H.

2001-06-01

33

Sound velocities in olivine at Earth mantle pressures.  

UK PubMed Central (United Kingdom)

The independent elastic constants of an upper mantle mineral, San Carlos olivine [(Mg(1.8)Fe(0.2))SiO(4)], were measured from 0 to 12.5 gigapascals. Evidence is offered in support of the proposition that the explicit temperature dependence of the bulk modulus is small over the range of temperatures and pressures thought to prevail above the 400-kilometer discontinuity, and thus the data can be extrapolated to estimate the properties of olivine under mantle conditions at a depth of 400 kilometers. In the absence of high-temperature data at high pressures, estimates are made of the properties of olivine under mantle conditions to a depth of 400 kilometers. In contrast with low-pressure laboratory data, the predicted covariance of shear and compressional velocities as a function of temperature nearly matches the seismically estimated value for the lower mantle.

Zaug JM; Abramson EH; Brown JM; Slutsky LJ

1993-06-01

34

Sound velocities in olivine at Earth mantle pressures.  

Science.gov (United States)

The independent elastic constants of an upper mantle mineral, San Carlos olivine [(Mg(1.8)Fe(0.2))SiO(4)], were measured from 0 to 12.5 gigapascals. Evidence is offered in support of the proposition that the explicit temperature dependence of the bulk modulus is small over the range of temperatures and pressures thought to prevail above the 400-kilometer discontinuity, and thus the data can be extrapolated to estimate the properties of olivine under mantle conditions at a depth of 400 kilometers. In the absence of high-temperature data at high pressures, estimates are made of the properties of olivine under mantle conditions to a depth of 400 kilometers. In contrast with low-pressure laboratory data, the predicted covariance of shear and compressional velocities as a function of temperature nearly matches the seismically estimated value for the lower mantle. PMID:17739804

Zaug, J M; Abramson, E H; Brown, J M; Slutsky, L J

1993-06-01

35

Measurement of earth pressures on concrete box culverts under highway embankments  

Energy Technology Data Exchange (ETDEWEB)

To obtain a better understanding of the stresses acting on cast-in-place concrete box culverts, and to investigate the conditions which resulted in a culvert failure under about 12 meters of backfill, two sections of a new culvert were instrumented. The measured earth pressure distribution was found to depend upon the height of the embankment over the culvert. For low embankment heights (less than one-half the culvert width), the average measured vertical earth pressures, weighted by tributary length, were about 30% greater than the recommended AASHTO pressures. The measured lateral pressures were slightly greater than the AASHTO pressures. As the embankment height increased, the measured weighted average vertical stress exceeded the AASHTO pressures by about 20%. Lateral pressures which exceeded the vertical pressures were recorded at the bottom of the culvert walls, and small lateral pressures were recorded on the upper locations of the wall. The high lateral pressures at the base of the wall are consistent with the results from finite element analyses with high density (modulus) backfill material placed around the culvert.

Yang, M.Z.; Drumm, E.C.; Bennett, R.M.; Mauldon, M.

1999-07-01

36

Three-dimensional axisymmetric magnetosphere in pressure balance with the solar wind  

Energy Technology Data Exchange (ETDEWEB)

A computer model of a magnetosphere in which the magnetic dipole axis points into the solar wind has been developed. The axial symmetry implied by this physical situation admits a two dimensional treatment. The model features (1) a magnetopause in pressure balance with the solar wind, (2) an analytic asymptotic tail model to account for the distant magnetotail, and (3) a full accounting of the magnetohydrodynamic pressure in the magnetosphere. The plasma pressure is a function of the Euler potential, chi(=rA phi). The principal physical result is that with an increase in the plasma pressure from zero the magnetic field configuration changes slowly at first. As the pressure increased further, the field configuration changes more rapidly until X and O lines are formed.

Yates, G.K.; Heinemann, M.

1986-06-01

37

Effects of ground inhomogeneities on the heat balance of the earth's surface. Einfluss von Inhomogenitaeten des Untergrundes auf den Waermehaushalt der Oberflaeche  

Energy Technology Data Exchange (ETDEWEB)

The effects of ground inhomogeneities on the heat balance are discussed on the basis of the energy balance of the earth's surface and the energy flows which determine it. An algorithm is introduced for determination of the sensible and latent heat fluxes from vertical temperature and specific-moisture profiles which were measured under horizontally homogeneous field conditions. (orig.).

Linse, A.; Tetzlaff, G. (Inst. fuer Meteorologie und Klimatologie der Univ. Hannover (Germany))

1991-01-01

38

Highly balanced single-layer high-temperature superconductor SQUID gradiometer freely movable within the Earth's magnetic field  

International Nuclear Information System (INIS)

[en] We developed a gradiometer system based on a single-layer high-temperature superconductor dc superconducting quantum interference device (SQUID), which can be freely moved within the Earth's magnetic field during measurement. The problem of circumferential shielding currents in the parallel gradiometer pick-up loop is solved by the use of an appropriately designed magnetometer SQUID integrated on the gradiometer chip. The magnetometer's feedback coil of the flux-locked loop is laid out as a small Helmholtz coil pair, thus keeping the homogeneous magnetic field constant for both the magnetometer and the gradiometer. Therefore, the balance of the directly coupled gradiometer SQUID is enhanced from 100 up to 3800. The noise limited magnetic field gradient resolution of 45 pT m-1 Hz-1/2 is preserved down to frequencies of several Hz even after strong motion in the Earth's magnetic field

2003-07-01

39

Lateral Earth Pressure at Rest and Shear Modulus Measurements on Hanford Sludge Simulants.  

Science.gov (United States)

This report describes the equipment, techniques, and results of lateral earth pressure at rest and shear modulus measurements on kaolin clay as well as two chemical sludge simulants. The testing was performed in support of the problem of hydrogen gas rete...

A. D. Guzman B. E. Wells G. Boeringa J. J. Jenks N. N. Bauman P. Arduino P. J. Keller

2010-01-01

40

Active and passive critical slip fields for cohesionless soils and calculation of lateral earth pressures  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A new method of solving earth pressure problems is proposed in this paper within the framework of the limit equilibrium approach. The concept of the critical slip field (CSF) is postulated: the active critical slip field (ACSF) in the active case, and the passive critical slip field (PCSF) in the pa...

Zhu, DY; Qian, QH; Lee, CF

 
 
 
 
41

Exposure of phototrophs to 548 days in low Earth orbit: microbial selection pressures in outer space and on early earth.  

UK PubMed Central (United Kingdom)

An epilithic microbial community was launched into low Earth orbit, and exposed to conditions in outer space for 548 days on the European Space Agency EXPOSE-E facility outside the International Space Station. The natural phototroph biofilm was augmented with akinetes of Anabaena cylindrica and vegetative cells of Nostoc commune and Chroococcidiopsis. In space-exposed dark controls, two algae (Chlorella and Rosenvingiella spp.), a cyanobacterium (Gloeocapsa sp.) and two bacteria associated with the natural community survived. Of the augmented organisms, cells of A. cylindrica and Chroococcidiopsis survived, but no cells of N. commune. Only cells of Chroococcidiopsis were cultured from samples exposed to the unattenuated extraterrestrial ultraviolet (UV) spectrum (>110?nm or 200?nm). Raman spectroscopy and bright-field microscopy showed that under these conditions the surface cells were bleached and their carotenoids were destroyed, although cell morphology was preserved. These experiments demonstrate that outer space can act as a selection pressure on the composition of microbial communities. The results obtained from samples exposed to >200?nm UV (simulating the putative worst-case UV exposure on the early Earth) demonstrate the potential for epilithic colonization of land masses during that time, but that UV radiation on anoxic planets can act as a strong selection pressure on surface-dwelling organisms. Finally, these experiments have yielded new phototrophic organisms of potential use in biomass and oxygen production in space exploration.

Cockell CS; Rettberg P; Rabbow E; Olsson-Francis K

2011-10-01

42

Exposure of phototrophs to 548 days in low Earth orbit: microbial selection pressures in outer space and on early earth.  

Science.gov (United States)

An epilithic microbial community was launched into low Earth orbit, and exposed to conditions in outer space for 548 days on the European Space Agency EXPOSE-E facility outside the International Space Station. The natural phototroph biofilm was augmented with akinetes of Anabaena cylindrica and vegetative cells of Nostoc commune and Chroococcidiopsis. In space-exposed dark controls, two algae (Chlorella and Rosenvingiella spp.), a cyanobacterium (Gloeocapsa sp.) and two bacteria associated with the natural community survived. Of the augmented organisms, cells of A. cylindrica and Chroococcidiopsis survived, but no cells of N. commune. Only cells of Chroococcidiopsis were cultured from samples exposed to the unattenuated extraterrestrial ultraviolet (UV) spectrum (>110?nm or 200?nm). Raman spectroscopy and bright-field microscopy showed that under these conditions the surface cells were bleached and their carotenoids were destroyed, although cell morphology was preserved. These experiments demonstrate that outer space can act as a selection pressure on the composition of microbial communities. The results obtained from samples exposed to >200?nm UV (simulating the putative worst-case UV exposure on the early Earth) demonstrate the potential for epilithic colonization of land masses during that time, but that UV radiation on anoxic planets can act as a strong selection pressure on surface-dwelling organisms. Finally, these experiments have yielded new phototrophic organisms of potential use in biomass and oxygen production in space exploration. PMID:21593797

Cockell, Charles S; Rettberg, Petra; Rabbow, Elke; Olsson-Francis, Karen

2011-05-19

43

Temperature dependence of molecular atmospheric transmission function in field of 2--400 {micro}m and the earth radiation balance  

Energy Technology Data Exchange (ETDEWEB)

The global climate change problem becomes actual by the end of the 20th century. Its many important aspects are: the change of molecular composition of the earth`s atmosphere (in particular, the accumulation of CO{sub 2}, CH{sub 4}, SO{sub 2} in the atmosphere), and the problem of ozone layer depletion. This paper is devoted to the investigation of fundamental mechanisms of the atmospheric transmission function influence, in the field of 2--400 mm and especially in the range of windows 8--13 mm and 3--4 mm, on the thermal balance of the earth`s atmosphere. The negative and positive feedbacks between the absorption of the outgoing heat radiation in the atmosphere and the heating of the earth`s surface have been considered. All the simulations of the infrared radiation transfer are based on spectral data from GEISA-92 data bank. Temperature dependence of molecular transmission function has been obtained and three steady states for earth`s radiation balance were shown to exist. A radiation balance regime, leading to closing of the atmospheric window 8--13 mm and development of the explosive greenhouse effect has been obtained and discussed in this paper.

Zakharov, V.I.; Gribanov, K.G.; Falko, M.V.; Golovko, V.F.; Chursin, A.A.; Nikitin, A.V.; Husson, N.; Scott, N.A.; Tyuterev, V.G.

1996-12-31

44

Measuring the initial earth pressure of granite using hydraulic fracturing test; Goseong and Yuseong areas  

Energy Technology Data Exchange (ETDEWEB)

This report provides the initial earth pressure of granitic rocks obtained from Deep Core Drilling Program which is carried out as part of the assessment of deep geological environmental condition. These data are obtained by hydraulic fracturing test in three boreholes drilled up to 350{approx}500 m depth at the Yuseong and Goseong sites. These sites were selected based on the result of preliminary site evaluation study. The boreholes are NX-size (76 mm) and vertical. The procedure of hydraulic fracturing test is as follows: - Selecting the testing positions by preliminary investigation using BHTV logging. - Performing the hydraulic fracturing test at each selected position with depth.- Estimating the shut-in pressure by the bilinear pressure-decay-rate method. - Estimating the fracture reopening pressure from the pressure-time curves.- Estimating the horizontal principal stresses and the direction of principal stresses. 65 refs., 39 figs., 12 tabs. (Author)

Park, Byoung Yoon; Bae, Dae Seok; Kim, Chun Soo; Kim, Kyung Su; Koh, Young Kwon; Won, Kyung Sik [Korea Atomic Energy Research Institute, Taejeon (Korea)

2002-02-01

45

Smoothly waning, symmetrically expanding, cavity-pressure loads in earth materials  

International Nuclear Information System (INIS)

An approximate solution for the pressure loading required to expand a spherical cavity in rock and soil targets is derived. A dual characterization of fracture and flow material model is used. Frictional resistance to flow is also included. Non-linear volumetric strain hardening is modeled with bi-linear curves and unloading is assumed to be non-dilative. Applications of this solution form to the prediction of pressure loading on slender, convex-nosed earth penetrators and on spherically-nosed water entry vehicles are discussed.

1982-01-01

46

Properties of liquid iron along the melting line up to Earth-core pressures.  

UK PubMed Central (United Kingdom)

We report a molecular dynamics study of the transport coefficients and the infinite frequency shear modulus of liquid iron at high temperatures and high pressures. We observe a simultaneous rise of both the shear viscosity and the diffusion coefficient along the melting line and estimate whether liquid iron can vitrify under Earth-core conditions. We show that in the conditions of the model studied in our work iron demonstrates a moderate increase of viscosity along the melting line. It is also demonstrated that at the limit of high temperatures and high pressures the liquid iron behaves similarly to the soft sphere system with exponent n ? 4.6.

Fomin YD; Ryzhov VN; Brazhkin VV

2013-07-01

47

Structural and electronic properties of alkaline-earth fluorohalides under pressure  

Science.gov (United States)

The electronic band structure of the mixed alkaline-earth fluorohalides-CaFCl, SrFCl, BaFCl, BaFBr, and BaFI in the PbFCl-type structure-were calculated using the tight-binding linear muffin-tin orbital method within the local-density approximation. The total energies calculated within the atomic sphere approximation were used to determine the ground-state properties of these systems. The calculated equilibrium lattice parameters, c/a ratio, the bulk modulus, and the pressure-volume relation were found to be in good agreement with the experimental results. The energy band-gap value at ambient conditions and the pressure dependence of the band gap for these systems were also obtained. These systems are found to be direct band-gap insulators with the band gap initially increasing with pressure which decreases upon further compression leading to band-overlap metallization at high pressures.

Kalpana, G.; Palanivel, B.; Shameem Banu, I. B.; Rajagopalan, M.

1997-08-01

48

La Presion Y la Estructura Interna de la Tierra (The Pressure and the Internal Structure of Earth).  

Science.gov (United States)

The authors attempt to solve the problem of the internal constitution of the earth and its origin supported by the significant role of the pressure on mineral stability and its implication in the general picture of the earth. The development of modern hig...

J. L. Amoros A. S. Miguel

1966-01-01

49

The differential effects of foot sole sensory on plantar pressure distribution between balance and gait.  

UK PubMed Central (United Kingdom)

UNLABELLED: Foot sole tactile sensation provides valuable feedback to the central nervous system. Acutely reduced foot sensation changes plantar pressure distribution in standing and gait; however, the effect of chronic foot sole sensory impairment on plantar pressure distribution is unclear. PURPOSE: This study aims to examine the effects of peripheral neuropathy (PN) induced chronic sensory loss on plantar pressure distribution in walking and standing. METHODS: Foot sole sensitivity was tested at the five sites: big toe (BT), 1st metatarsal (M1), 5th metatarsal (M5), mid-foot (MF) and heel (HL). Relative peak pressures (RPP) of the five sites were collected during a 20-s walking on a treadmill at .45 m/s and a 30-s quiet standing with eyes open. Five-way MANOVA was used to examine the influence of sensitivity of each site on overall plantar pressure distribution for standing and walking separately. Tukey's test was used to examine the significant associations. RESULTS: In standing, the sensitivity of BT affected average RPP at BT significantly (P<.05), where RPP associated with insensitive BT (8.1±5.7%) was greater than with sensitive BT (4.5±4.9%). Furthermore, the RPP at HL was greater for insensitive MF (36.1±17.9%) compared with sensitive MF (23.6±7.4%) (P<.05). No pressure distribution changes were observed in walking. CONCLUSIONS: Feedback from foot sole tactile sensation in gait is not as significant as in standing, showing standing balance control relies more on feedback control mechanism while gait control relies more on feed forward control mechanism.

Zhang S; Li L

2013-04-01

50

Moderate pressure synthesis of rare earth nickelate with metal-insulator transition using polymeric precursors  

International Nuclear Information System (INIS)

Rare earth nickelates exhibit a reversible metal-semiconductor phase transition that is, in the infrared range, responsible for a thermo-optical contrast. The state of the art synthesis of these compounds usually requires high oxygen pressure to stabilize Ni in the oxidation state 3+. In this work, using polymeric precursor associated with moderate pressure annealing, we show that it is possible to obtain fully oxidized rare earth nickelate with metal-insulator transition. Using thermogravimetric analysis, X-ray diffraction and transmission electronic microscopy we compare different samples synthesized at different oxygen pressures and demonstrate their structural similarity. Thermo-optical properties were measured, in the infrared range, using reflectance measurements and confirmed the metal-insulator transition at 60 oC in both samples.TEM observations lead to the conclusion that the structure commonly obtained at 175 bar is perfectly observed in the 20 bar sample without major structural defects. The two samples exhibit a thermochromic behavior and thermo-optical properties of the two samples are equivalent. - Graphical Abstract: Thermochromic behavior of Nd0.3Sm0.7NiO3 samples annealed under 20 and 175 bar at 278 and 373 K.

2010-01-01

51

Modelling the rheology of MgO under Earth's mantle pressure, temperature and strain rates.  

UK PubMed Central (United Kingdom)

Plate tectonics, which shapes the surface of Earth, is the result of solid-state convection in Earth's mantle over billions of years. Simply driven by buoyancy forces, mantle convection is complicated by the nature of the convecting materials, which are not fluids but polycrystalline rocks. Crystalline materials can flow as the result of the motion of defects--point defects, dislocations, grain boundaries and so on. Reproducing in the laboratory the extreme deformation conditions of the mantle is extremely challenging. In particular, experimental strain rates are at least six orders of magnitude larger than in nature. Here we show that the rheology of MgO at the pressure, temperature and strain rates of the mantle is accessible by multiscale numerical modelling starting from first principles and with no adjustable parameters. Our results demonstrate that extremely low strain rates counteract the influence of pressure. In the mantle, MgO deforms in the athermal regime and this leads to a very weak phase. It is only in the lowermost lower mantle that the pressure effect could dominate and that, under the influence of lattice friction, a viscosity of the order of 10(21)-10(22) pascal seconds can be defined for MgO.

Cordier P; Amodeo J; Carrez P

2012-01-01

52

Lateral Earth Pressure at Rest and Shear Modulus Measurements on Hanford Sludge Simulants  

Energy Technology Data Exchange (ETDEWEB)

This report describes the equipment, techniques, and results of lateral earth pressure at rest and shear modulus measurements on kaolin clay as well as two chemical sludge simulants. The testing was performed in support of the problem of hydrogen gas retention and release encountered in the double- shell tanks (DSTs) at the Hanford Site near Richland, Washington. Wastes from single-shell tanks (SSTs) are being transferred to double-shell tanks (DSTs) for safety reasons (some SSTs are leaking or are in danger of leaking), but the available DST space is limited.

Wells, Beric E.; Jenks, Jeromy WJ; Boeringa, Gregory K.; Bauman, Nathan N.; Guzman, Anthony D.; Arduino, P.; Keller, P. J.

2010-09-30

53

Pressure change associated with dipolarization in the near-earth plasma sheet  

International Nuclear Information System (INIS)

[en] Complete text of publication follows. We have studied pressure changes that occur in association with dipolarization in the plasma sheet of the near-Earth magnetotail around substorm onsets. We performed a superposed epoch analysis using Geotail data. Here the contribution of high-energy particles to the ion pressure was considered. It is found that, unlike the previously reported results, the ion pressure increases in association with dipolarization at X ? -10 Re where the initial dipolarization takes place. This pressure change is largely contributed by high-energy particles. Tailward of this region, the ion pressure does not significantly increase even after the beginning of dipolarization, while it decreases in some cases; in both cases, the contribution of high-energy particles is not very large. Furthermore, the ion beta enhances around substorm expansion onset in the close vicinity of the magnetic equator of the initial dipolarization region. These observations suggest that the characteristics of the dipolarization differ between the initial dipolarization and tailward regions. We also examine in detail a few individual cases that were observed by Geotail and THEMIS in the vicinity of the magnetic equator. We also discuss implications for the rarefaction wave proposed in the current disruption model.

2009-01-01

54

Study on earth pressure behind a wall in the design of an earth-retaining structure in clayey soil; Nenseido jiban ni okeru kussaku dodomeko no sekkei yo haimen sokudoatsu ni kansuru kenkyu  

Energy Technology Data Exchange (ETDEWEB)

In order to derive earth pressure behind a wall used in the design of an earth-retaining structure in clayey soil, sensitivity in the parameters was analyzed by using the finite-element method, and an earth pressure equation including the parameters with high sensitivity was proposed. In order to determine its applicability, the proposal was compared with measurements at sites. Major findings from the comparison may be summarized as follows: the earth pressure behind a wall acting on an earth-retaining wall varies in association with the progress of excavation; transformation of the earth-retaining walls gives great influence on the variation, but the pressure differs from the ultimate earth pressure that assumes a large transformation; and factors affecting largely the earth pressure behind the wall include excavation depth, its width, bending rigidity of the earth-retaining wall, springs in the struts, static side pressure before the excavation, and strength and transformation characteristics of the ground bed. As a result of comparing the proposed equation including these parameters with the site measurements, it was found that the proposed equation can explain the variation in the earth pressure with practically sufficient accuracy. 19 refs., 24 figs., 9 tabs.

Nakamura, H. [Pacific Consultants Co. Ltd., Tokyo (Japan)

1994-12-20

55

Potassium partitioning into molten iron alloys at high-pressure: Implications for Earth's core  

Science.gov (United States)

It has long been known that the Earth's mantle is more depleted in potassium, than C1-chondrites [1,2]. Two major mechanisms could explain this depletion: (i) the depletion is due to potassium volatility during the early stages of planetary accretion, or (ii) potassium has been incorporated into the core during segregation of an iron-rich metallic liquid. The potassium isotopic composition data of most solar system material place strong limits of 2% on the quantity of potassium that could have been lost by volatilization, ruling out any considerable volatilization or evaporation of potassium [3]. Thus, at least part of the potassium deficit in the mantle might be due to the incorporation of K into the core. To provide strong constraints on the potassium content of the core at the time of Earth's formation, multi-anvil experiments were carried out to determine the partition coefficients of potassium between molten silicates and iron alloy liquids (S-free and S-bearing alloys), between 5 and 15 GPa, at a temperature of 2173 K, and at an oxygen fugacity about 2 log units below the iron-wustite (IW) buffer. No pressure dependence of the potassium partition coefficients in S-free and S-bearing systems was found within the investigated pressure range. We also shown that the degree of melt polymerization is not a controling factor for K partitioning in compositions relevant to the Earth's mantle. We review all available high-pressure data to obtain reliable partition coefficients for the interaction between molten silicates and Fe-alloy liquids at pressures and temperatures relevant to those of core formation in a terrestrial magma ocean. All the existing data, for an oxygen fugacity of about 2 orders of magnitude lower than the IW buffer, and for compositions relevant to the Earth's mantle, and at 2173 K plot around a constant value of 0.083 ± 0.051 and 0.0063 ± 0.0019 for S-bearing and S-free metal, respectively [4]. The dominant controlling parameters appear to be the temperature and the chemical composition of the metallic phase, with potassium partitioning coefficients significantly increased with temperature, and with the sulphur and oxygen contents of the Fe-alloy liquid. Our considerations distinguish too extreme cases, with an S-free or S-rich iron core, which yield K-contents of ~25 or ~250 ppm, respectively. These two extreme values have very different consequences for thermal budget models of the Earth's core since its formation. [1] Gast, P.W., 1960. J. Geophys. Res. 65, 1287. [2] Wasserburg, G.J. et al. 1964. Science 143, 465. [3] Humayon, M., Clayton, R.N., 1995. Geochim. Cosmochim. Acta 59, 2131. [4] Bouhifd, M.A. et al. 2006. Phys. Earth Planet. Int., (under review).

Bouhifd, M.; Gautron, L.; Bolfan-Casanova, N.; Malavergne, V.; Hammouda, T.; Andrault, D.; Jephcoat, A.

2006-12-01

56

Variations of the Earth's figure axis caused by pressure changes in the core  

Science.gov (United States)

Significant variations in the degree two and order one geopotential coefficients: C21 and S21 have been observed from analysis of the Satellite Laser Ranging (SLR) and GRACE data. The geopotential coefficients: C21and S21, from SLR and GRACE data determine the principal figure axis of the entire Earth with respect to the z-axis of the terrestrial reference system as defined by the mean rotation axis on the mantle. The changes in the pattern of flow in the core result in the pressure variations acting at the core-mantle boundary (CMB), in turn, cause deformation of the mantle and produce a torque on the core. Thus, the observed mean figure axis from the recent GRACE and SLR solution could provide improved constant on the Earth's core dynamics: tilt of the core figure axis from the mantle axis. We investigate the effects on the variations of the C21/S21 and lower degree zonal harmonics coefficients due to the surface deformation and torque changes of the mantle induced by the fluid pressure at CMB.

Cheng, Minkang; Fang, Ming

2010-05-01

57

Metal-silicate partitioning of potassium at high pressure and temperature conditions and implications for thermal history of the Earth  

Science.gov (United States)

The possible presence of potassium in the Earth's core as a radioactive heat source can have a significant influence on the thermal evolution of the Earth (Buffett, 2002 GRL; Labrosse, 2003 PEPI). Core-mantle equilibration at high P-T (e.g. ~30 GPa, ~3450 K [Righter, 2011 EPSL]) was suggested from the mantle contents of siderophile elements. Basal magma ocean (Labrosse et al., 2007 Nature) also should be equilibrated with molten iron at the core-mantle boundary (CMB) (~135 GPa) due to its gravitational stability (Nomura et al., 2011 Nature). Previous experimental studies on potassium partitioning between liquid metal and silicate melt showed contradictory results on the concentration of potassium in the Earth's core because of experimental artifacts (K loss in metal phase), different (simplified) chemical compositions for study and large extrapolations to high P-T which suits for core-mantle equilibration at the base of the magma ocean. Recently, Corgne et al. (2007 EPSL) performed the partitioning experiments up to 7.7 GPa and 2200°C with chemical compositions of CI chondrite doped with moderate amount of S and K and revealed a significant effect of O contents in molten alloy on K partition coefficient while with negligible effect of P-T and S and C contents. The change in electronic structure of potassium from 4s- to 3d-like was predicted by theory (Bukowinski, 1976 GRL) and potassium alloying with nickel and iron was reported by experiments using diamond anvil cell at ~30 GPa and 2200 K (Parker et al., 1997 Science; Lee and Jeanloz, 2003 GRL). So, it is important to investigate the effect of pressure on K partition coefficient at the pressure conditions above ~30 GPa up to 135 GPa. Hirao et al. (2006 GRL) performed melting experiment at 135 GPa and 3500 K using laser-heated diamond anvil cell (LHDAC) and showed the value of partition coefficient Dk is 0.15, but their results lack the elemental mass balances between run products and starting materials. Our melting experiments were performed at high P-T conditions using LHDAC. Fine powdered mixtures of Fe (or Fe-FeS, Fe-FeSi) metal and gels with chemical compositions of KLB-1 peridotite doped with 1wt% K were used as a starting material. The gel powder was dehydrated by heating to 1273 K for 1 h in a H2-CO2 gas mixing furnace, in which oxygen fugacity was controlled to be slightly above the iron-wustite buffer. Pressure was measured after quenching with the Raman shift of diamond anvil. Ar was used as a pressure medium. The sample was heated from double side using Nd:YLF laser. A recovered sample was processed with Ion Slicer (JEOL EM-09100 IS), and subsequently examined by energy-dispersive X-ray spectrometry (EDS) attached with field emission scanning electron microscope (FE-SEM: JOEL JSM-7000F). Our preliminary results at ~20 GPa, fO2 of ~IW-1 and high temperature up to 5000 K with KLB-1 gel and S-free metal shows the clear correlation between O contents in molten iron and K partition coefficients suggested by Corgne et al. (2007). The results of partitioning coefficient at high P-T range up to primordial CMB conditions will be discussed in our presentation.

Nomura, R.; Hirose, K.

2011-12-01

58

Digitalis-like activity in human plasma: Relation to blood pressure and sodium balance  

Energy Technology Data Exchange (ETDEWEB)

PURPOSE: On the assumption that renal tubular cells are more important as the target cells for a natriuretic factor than blood cells, we used a well-characterized cultured renal tubular cell line, Madin-Darby canine kidney (MDCK), cells to monitor the circulating digitalis-like factor in human plasma and examine its role in the regulation of blood pressure and sodium balance. SUBJECTS AND METHODS: We investigated the effects of plasma on binding of radioactive ouabain to monolayered MDCK cells in order to determine the level of a circulating digitalis-like factor. First, we measured specific 3H-ouabain binding to MDCK cells in the presence of plasma from 71 outpatients (34 normotensive subjects and 37 hypertensive patients) after incubation for 4 hours. Second, we measured specific 3H-ouabain binding after incubation of cells with plasma from 16 hospitalized subjects (eight normotensive subjects and eight hypertensive patients) receiving low and high sodium diets. RESULTS: In Study 1, ouabain binding was lower by 30% with plasma from hypertensive patients than with plasma from normotensive subjects (p less than 0.01). There was a significant negative correlation between individual subject's systolic or mean blood pressure and ouabain binding (r = -0.34, p less than 0.01 or r = -0.29, p less than 0.01). In Study 2, ouabain binding was also significantly reduced by 25% in the presence of plasma from hypertensive subjects as compared with plasma from normotensive subjects irrespective of sodium intake (p less than 0.01). A significant negative correlation was also found for all subjects between either systolic, diastolic, or mean blood pressure and ouabain binding (r = -0.58, p less than 0.01, r = -0.51, p less than 0.01, or r = -0.55, p less than 0.01, respectively).

Goto, A.; Yamada, K.; Ishii, M.; Sugimoto, T. (Univ. of Tokyo (Japan))

1990-10-01

59

Digitalis-like activity in human plasma: Relation to blood pressure and sodium balance  

International Nuclear Information System (INIS)

PURPOSE: On the assumption that renal tubular cells are more important as the target cells for a natriuretic factor than blood cells, we used a well-characterized cultured renal tubular cell line, Madin-Darby canine kidney (MDCK), cells to monitor the circulating digitalis-like factor in human plasma and examine its role in the regulation of blood pressure and sodium balance. SUBJECTS AND METHODS: We investigated the effects of plasma on binding of radioactive ouabain to monolayered MDCK cells in order to determine the level of a circulating digitalis-like factor. First, we measured specific 3H-ouabain binding to MDCK cells in the presence of plasma from 71 outpatients (34 normotensive subjects and 37 hypertensive patients) after incubation for 4 hours. Second, we measured specific 3H-ouabain binding after incubation of cells with plasma from 16 hospitalized subjects (eight normotensive subjects and eight hypertensive patients) receiving low and high sodium diets. RESULTS: In Study 1, ouabain binding was lower by 30% with plasma from hypertensive patients than with plasma from normotensive subjects (p less than 0.01). There was a significant negative correlation between individual subject's systolic or mean blood pressure and ouabain binding (r = -0.34, p less than 0.01 or r = -0.29, p less than 0.01). In Study 2, ouabain binding was also significantly reduced by 25% in the presence of plasma from hypertensive subjects as compared with plasma from normotensive subjects irrespective of sodium intake (p less than 0.01). A significant negative correlation was also found for all subjects between either systolic, diastolic, or mean blood pressure and ouabain binding (r = -0.58, p less than 0.01, r = -0.51, p less than 0.01, or r = -0.55, p less than 0.01, respectively).

1990-01-01

60

Reliability and Sex Differences in the Foot Pressure Load Balance Test and Its Relationship to Physical Characteristics in Preschool Children  

Directory of Open Access Journals (Sweden)

Full Text Available This study aimed to examine the trial-to-trial reliability and sex differences in a foot pressure load balance test and its relationship to physical characteristics in 396 preschool children (201 boys and 195 girls). The subjects were asked to maintain an upright standing posture for 10 seconds three times on the Footview Clinic, an instrument designed to calculate the right-left and anterior-posterior ratios of foot pressure load. The ratios of the left and anterior foot pressure loads in right and left feet were selected as variables. Intra-class correlation coefficients between the second and third trials in all variables were high (intra-class correlation coefficients = 0.70 - 0.90). The above variables showed insignificant sex differences and little relationships with physique. When measuring foot pressure load balance, it is desirable to use a mean of the second and third trials as a representative.

Shigeki Matsuda; Shinichi Demura; Kosho Kasuga; Hiroki Sugiura

2012-01-01

 
 
 
 
61

Pressure changes associated with substorm depolarization in the near-Earth plasma sheet  

Science.gov (United States)

We have studied plasma (ion) pressure changes that occurred in association with the dipolarization in the near-Earth plasma sheet around substorm onsets. Using Geotail data, we have performed a superposed epoch analysis in addition to detailed examinations of two individual cases with special emphasis on the contribution of high-energy particles to the plasma pressure. It is found that, unlike previously reported results, the plasma pressure does increase in association with the initial dipolarization at X > ˜-12 RE and -2 < Y < 6 RE, with the increase largely due to high-energy particles. Outside the initial dipolarization region, particularly tailward and duskward of this region, the plasma pressure begins to decrease owing to the magnetic reconnection before onset or before the dipolarization region reaches there. At later times, the plasma pressure tends to increase there, related to the expanding dipolarization region, but the contribution of high-energy particles is not very large. These observations suggest the following. The rarefaction wave scenario proposed in the current disruption model is questionable. The radial and azimuthal pressure gradients may strengthen between the initial dipolarization and outside regions, possibly resulting in stronger braking of fast earthward flows and changes in field-aligned currents. The characteristics of the dipolarization may differ between the initial dipolarization and tailward regions, which would be possibly reflected in the auroral features. Furthermore, we have examined the specific entropy and the ion ?. The specific entropy increases in the plasma sheet in the dipolarization region as well as in the midtail region in conjunction with substorm onsets, suggesting from the ideal MHD point of view that the substorm processes are nonadiabatic. The ion ? is found to peak at the magnetic equator in the initial dipolarization region around dipolarization onsets.

Miyashita, Y.; Machida, S.; Ieda, A.; Nagata, D.; Kamide, Y.; Nosé, M.; Liou, K.; Mukai, T.; Christon, S. P.; Russell, C. T.; Shinohara, I.; Saito, Y.

2010-12-01

62

Study on passive earth pressure acting on the embedment of an earth retaining wall for braced excavation work in cohesive soil; Nenseido jiban ni okeru kussaku dodomeheki neirebu no judo doatsu ni kansuru kenkyu  

Energy Technology Data Exchange (ETDEWEB)

Passive earth pressure exerts a great influence on the stress and deformation of earth retaining walls in braced excavation. To calculate this pressure, conventional ultimate earth pressure equation, or Rankine-Resals and Coulomb`s equation, are currently applied respectively to cohesive and sandy soil. However, these intentional equation to determine passive earth pressure do not adequately take into account the excavation width during work and the shearing resistance on the earth retaining wall surface. This paper deals with cohesive soil only, deriving a calculation equation for passive earth pressure, which takes into account excavation width and the shearing resistance of the earth retaining wall surface. Then, constants in this equation are determined using the calculation results obtained from the finite element method with blasts-plastic elements. The calculation results are also compared with measured values in the model test in order to check the applicability of the calculation equation for passive earth pressure thus obtained. Finally, this paper proposes a practicable calculation equation for passive earth pressure. 13 refs., 10 figs., 10 tabs.

Nakamura, H. [Pacific Consultants K.K., Tokyo (Japan); Hirashima, K. [Yamanashi University, Yamanashi (Japan). Faculty of Engineering

1995-12-15

63

Physical and numerical modelling of earth pressure on anchored sheet pile walls in sand  

DEFF Research Database (Denmark)

The influence of wall flexibility on earth pressure, bending moments and failure modes is studied. Numerical models are compared to results from model tests carried out in a geotechnical centrifuge. The back-fill is dry sand and failure is introduced by allowing the wall to rotate around the anchor level. The Finite element program PLAXIS is used and two material models are evaluated, the Mohr-Coulomb model and the Hardening Soil model. The differences between the two concern the deformation properties. Generally good agreement was observed between physical and numerical models. The HS-model showed the right behaviour in pre-failure as well as failure for both flexible and stiff walls, whereas the MC-model showed some shortcomings when stiff walls were modelled.

KrogsbØll, Anette Susanne; Fuglsang, Leif D

2006-01-01

64

Pressure and Energy Balance of Stagnating Plasmas in z-Pinch Experiments: Implications to Current Flow at Stagnation.  

UK PubMed Central (United Kingdom)

Detailed spectroscopic diagnostics of the stagnating plasma in two disparate z pinches allow, for the first time, the examination of the plasma properties within a 1D shock wave picture, demonstrating a good agreement with this picture. The conclusion is that for a wide range of imploding-plasma masses and current amplitudes, in experiments optimizing non-Planckian hard radiation yields, contrary to previous descriptions the stagnating plasma pressure is balanced by the implosion pressure, and the radiation energy is provided by the imploding-plasma kinetic energy, rather than by the magnetic-field pressure and magnetic-field-energy dissipation, respectively.

Maron Y; Starobinets A; Fisher VI; Kroupp E; Osin D; Fisher A; Deeney C; Coverdale CA; Lepell PD; Yu EP; Jennings C; Cuneo ME; Herrmann MC; Porter JL; Mehlhorn TA; Apruzese JP

2013-07-01

65

Pressure and energy balance of stagnating plasmas in z-pinch experiments: implications to current flow at stagnation.  

UK PubMed Central (United Kingdom)

Detailed spectroscopic diagnostics of the stagnating plasma in two disparate z pinches allow, for the first time, the examination of the plasma properties within a 1D shock wave picture, demonstrating a good agreement with this picture. The conclusion is that for a wide range of imploding-plasma masses and current amplitudes, in experiments optimizing non-Planckian hard radiation yields, contrary to previous descriptions the stagnating plasma pressure is balanced by the implosion pressure, and the radiation energy is provided by the imploding-plasma kinetic energy, rather than by the magnetic-field pressure and magnetic-field-energy dissipation, respectively.

Maron Y; Starobinets A; Fisher VI; Kroupp E; Osin D; Fisher A; Deeney C; Coverdale CA; Lepell PD; Yu EP; Jennings C; Cuneo ME; Herrmann MC; Porter JL; Mehlhorn TA; Apruzese JP

2013-07-01

66

Pressure and Energy Balance of Stagnating Plasmas in z-Pinch Experiments: Implications to Current Flow at Stagnation  

Science.gov (United States)

Detailed spectroscopic diagnostics of the stagnating plasma in two disparate z pinches allow, for the first time, the examination of the plasma properties within a 1D shock wave picture, demonstrating a good agreement with this picture. The conclusion is that for a wide range of imploding-plasma masses and current amplitudes, in experiments optimizing non-Planckian hard radiation yields, contrary to previous descriptions the stagnating plasma pressure is balanced by the implosion pressure, and the radiation energy is provided by the imploding-plasma kinetic energy, rather than by the magnetic-field pressure and magnetic-field-energy dissipation, respectively.

Maron, Y.; Starobinets, A.; Fisher, V. I.; Kroupp, E.; Osin, D.; Fisher, A.; Deeney, C.; Coverdale, C. A.; Lepell, P. D.; Yu, E. P.; Jennings, C.; Cuneo, M. E.; Herrmann, M. C.; Porter, J. L.; Mehlhorn, T. A.; Apruzese, J. P.

2013-07-01

67

Study and dynamic modeling of a pressure transducer that is based on the principle of force balance  

Energy Technology Data Exchange (ETDEWEB)

The development of an analytical model for one type of pressure transducer that is used in nuclear power plants is discussed. It is a Foxboro E13DM force balance transducer with applications for flow, level and low pressure measurements. The model is based in studying the propagation of mechanical vibrations through the mechanical linkages of the transducer. The electronic circuit of the transducer is responsible for the feedback force that balances the system, and it was considered in the model. The frequency response as predicted by the model was compared with three sets of experimental data. The results showed good agreement in the region of analysis. Two 'in-situ' tests were developed for the transducer. One can be performed remotely, during normal operation of the plant. The other requires access to the transducer. The tests allow one to obtain the step response of the transducer. Neither of the tests require access to the pressure line.

Soares, A.J.

1982-01-01

68

Exposure of phototrophs to 548 days in low Earth orbit: microbial selection pressures in outer space and on early earth  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An epilithic microbial community was launched into low Earth orbit, and exposed to conditions in outer space for 548 days on the European Space Agency EXPOSE-E facility outside the International Space Station. The natural phototroph biofilm was augmented with akinetes of Anabaena cylindrica and vege...

Cockell, Charles S; Rettberg, Petra; Rabbow, Elke; Olsson-Francis, Karen

69

Unusual pressure dependence of the crystallographic structure in RNiO{sub 3} perovskites (R = rare earth)  

Energy Technology Data Exchange (ETDEWEB)

We report the first experimental observation of a pressure-induced structural phase transition in the RNiO{sub 3} series (R = rare earth). At {approx_equal} 40 kbar, the space group of NdNiO{sub 3} changes from Pbnm(orthorhombic) to the PrNiO{sub 3} indicating that the symmetry of the structure increases with pressure. (author) 1 fig., 7 refs.

Medarde, M.; Mesot, J.; Rosenkranz, S. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Lacorre, P. [Lab. Fluorures, Le Mans (France); Marshall, W.; Loveday, J.S. [Edinburgh Univ. (United Kingdom); Klotz, S.; Hamel, G. [Paris-6 Univ., 75 (France)

1997-09-01

70

High pressure synthesis of late rare earth RFeAs(O,F) superconductors; R = Tb and Dy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

New TbFeAs(O,F) and DyFeAs(O,F) superconductors with critical temperatures T-c = 46 and 45 K and very high critical fields, >= 100 T, have been prepared at 1100-1150 degrees C and 10-12 GPa, demonstrating that high pressure may be used to synthesise late rare earth derivatives of the recently report...

Attfield J.P.; Huxley A.D.; Sokolov D.A.; Rodgers J.A.; Penny G.B.S.; Bos J.W.G.

71

Fluid balance monitoring by cuff-occluded rate of rise of peripheral venous pressure in haemodialysis patients.  

UK PubMed Central (United Kingdom)

Cuff-occluded rate of rise of peripheral venous pressure has been proposed to reflect volume changes in experimental studies. The aim of this study was to evaluate changes in cuff-occluded rate of rise of peripheral venous pressure associated with fluid removal by haemodialysis in six adult patients with chronic renal failure on intermittent haemodialysis. Measurements were carried out before and after each haemodialysis session. The volume of fluid removed (indexed to body surface area) linearly correlated with changes in cuff-occluded rate of rise of peripheral venous pressure (r = 0.84; r(2) = 0.70; p = 0.037). Cuff-occluded rate of rise of peripheral venous pressure may be feasible for future clinical monitoring of individual fluid balance.

Pikwer A; Bergenzaun L; Sterner G; Krite Svanberg E; Akeson J

2012-08-01

72

Separation of rare earth precipitates from LiCl-KCl eutectic salts by a distillation at a reduced pressure - 16162  

International Nuclear Information System (INIS)

Distillation and condensation characteristics of LiCl-KCl eutectic salts containing rare earth precipitates were investigated to separate the rare earth precipitates from the salts effectively. The distillation flux of the salts was increased by about 1,000 times by reducing the ambient pressure from 760 Torr to 0.5 Torr. The salt vapors were almost changed into salt lumps during a salt distillation at the ambient pressure of 0.5 Torr and they were collected in the condensed salt storage. However, fine salt particles were formed when the salt distillation was processed at 10 Torr and it is difficult for them to be recovered. Therefore, it is thought that a salt vacuum distillation and condensation should be processed to recover almost all of the vaporized salts at a pressure below 0.5 Torr. (authors)

2009-01-01

73

Fe-C and Fe-H systems at pressures of the Earth's inner core  

Science.gov (United States)

The solid inner core of Earth is predominantly composed of iron alloyed with several percent Ni and some lighter elements, Si, S, O, H, and C being the prime candidates. To establish the chemical composition of the inner core, it is necessary to find the range of compositions that can explain its observed characteristics. Recently, there have been a growing number of papers investigating C and H as possible light elements in the core, but the results were contradictory. Here, using ab initio simulations, we study the Fe-C and Fe-H systems at inner core pressures (330-364 GPa). Based on the evolutionary structure prediction algorithm USPEX, we have determined the lowest-enthalpy structures of all possible carbides (FeC, Fe2C, Fe3C, Fe4C, FeC2, FeC3, FeC4, Fe7C3) and hydrides (Fe4H, Fe3H, Fe2H, FeH, FeH2, FeH3, FeH4) and have found that Fe2C (space group Pnma) is the most stable iron carbide at pressures of the inner core, while FeH, FeH3, and FeH4 are the most stable iron hydrides at these conditions. For Fe3C, the cementite structure (space group Pnma) and the Cmcm structure recently found by random sampling are less stable than the I-4 and C2/m structures predicted here. We have found that FeH3 and FeH4 adopt chemically interesting thermodynamically stable crystal structures, containing trivalent iron in both compounds. We find that the density of the inner core can be matched with a reasonable concentration of carbon, 11-15 mol.% (2.6-3.7 wt.%) at relevant pressures and temperatures, yielding the upper bound to the C content in the inner core. This concentration matches that in CI carbonaceous chondrites and corresponds to the average atomic mass in the range 49.3-51.0, in close agreement with inferences from Birch's law for the inner core. Similarly made estimates for the maximum hydrogen content are unrealistically high: 17-22 mol.% (0.4-0.5 wt.%), which corresponds to the average atomic mass of the core in the range 43.8-46.5. We conclude that carbon is a better candidate light alloying element than hydrogen.

Bazhanova, Zulfiya G.; Oganov, Artem R.; Gianola, Omar

2012-05-01

74

Experimental study on thermal-hydraulic behaviors of a pressure balanced coolant injection system for a passive safety light water reactor JPSR.  

Science.gov (United States)

A conceptual design study of a passive safety light water reactor JPSR has been performed at Japan Atomic Energy Research Institute JAERI. A pressure balanced coolant injection experiment has been carried out, with an objective to understand thermal-hydra...

T. Satoh H. Watanabe F. Araya K. Nakajima T. Iwamura

1998-01-01

75

High pressure synthesis of late rare earth RFeAs(O,F) superconductors; R = Tb and Dy.  

Science.gov (United States)

New TbFeAs(O,F) and DyFeAs(O,F) superconductors with critical temperatures T(c) = 46 and 45 K and very high critical fields, >or=100 T, have been prepared at 1100-1150 degrees C and 10-12 GPa, demonstrating that high pressure may be used to synthesise late rare earth derivatives of the recently reported RFeAs(O,F) (R = La-Nd, Sm, Gd) high temperature superconductors. PMID:18665282

Bos, Jan-Willem G; Penny, George B S; Rodgers, Jennifer A; Sokolov, Dmitry A; Huxley, Andrew D; Attfield, J Paul

2008-06-30

76

Stress in highly demanding IT jobs: transformational leadership moderates the impact of time pressure on exhaustion and work-life balance.  

UK PubMed Central (United Kingdom)

The objective of this article is to investigate transformational leadership as a potential moderator of the negative relationship of time pressure to work-life balance and of the positive relationship between time pressure and exhaustion. Recent research regards time pressure as a challenge stressor; while being positively related to motivation and performance, time pressure also increases employee strain and decreases well-being. Building on the Job Demand-Resources model, we hypothesize that transformational leadership moderates the relationships between time pressure and both employees' exhaustion and work-life balance such that both relationships will be weaker when transformational leadership is higher. Of seven information technology organizations in Germany, 262 employees participated in the study. Established scales for time pressure, transformational leadership, work-life balance, and exhaustion were used, all showing good internal consistencies. The results support our assumptions. Specifically, we find that under high transformational leadership the impact of time pressure on exhaustion and work-life balance was less strong. The results of this study suggest that, particularly under high time pressure, transformational leadership is an important factor for both employees' work-life balance and exhaustion.

Syrek CJ; Apostel E; Antoni CH

2013-07-01

77

Establishment of a force balanced piston gauge for very low gauge and absolute pressure measurements at NPL, India  

International Nuclear Information System (INIS)

[en] National Physical Laboratory, the National Metrology Institute (NMI) of India is maintaining Primary standards of pressure that cover several decades of pressure, starting from 3.0E-06 Pa to 1.0 GPa. Among which a recent addition is a Force Balanced Piston Gauge, the non-rotating piston type, having better resolution and zero stability compared to any other primary pressure standards commercially available in the range 1.0 Pa to 15.0 kPa (abs and gauge). The characterization of this FPG is done against Ultrasonic Interferometer Manometer (UIM), the National Primary pressure standard, working in the range 1.0 Pa to 130.0 kPa (abs and diff) and Air Piston Gauge (APG), a Transfer Pressure Standard, working in the range 6.5 kPa to 360 kPa (abs and gauge), in their overlapping pressure regions covering both absolute and gauge pressures. As NPL being one of the signatories to the CIPM MRA, the Calibration and Measurement Capabilities (CMC) of both the reference standards (UIM and APG), are Peer reviewed and notified in the Key Comparison Data Base (KCDB) of BIPM. The estimated mean effective area of the Piston Cylinder assembly of this FPG against UIM (980.457 mm2) and APG (980.463 mm2) are well within 4 ppm and 10 ppm agreement respectively, with the manufacturer's reported value (980.453 mm2). The expanded uncertainty of this FPG, Q(0.012 Pa, 0.0025% of reading), evaluated against UIM as reference standard, is well within the reported value of the manufacturer, Q(0.008 Pa, 0.003% of reading) at k = 2. The results of the characterization along with experimental setup and measurement conditions (for gauge and absolute pressure measurements), uncertainty budget preparation and evaluation of measurement uncertainty are discussed in detail in this paper.

2012-11-05

78

Studies on the high-pressure reaction of rare-earth sesquioxides with vanadium dioxide  

International Nuclear Information System (INIS)

The reaction of rare-earth sesquioxides (Ln2O3) with vanadium dioxide (VO2) at 1400sup(o)C and 50 kbar* * and 30 kbar was studied. Quadrivalent vanadium ions were reduced to the trivalent state, rare-earth vanadates (III) (LnVO3) being obtained. For LnVO3 a typical transformation of the ABO3-type compounds, one from the aragonite-type to the perovskite-type via the vaterie- or calcite-type structure was observed with a decrease in the ionic radius of the rare-earth ions. The magnetic properties of the vaterite-type LnVO3 were studied. (author)

1982-01-01

79

Laterality of lower limbs and relationship with the plantar pressure distribution in the static balance  

Directory of Open Access Journals (Sweden)

Full Text Available The distribution of loads during gait has been evaluated in many studies, some of which have been seen to influence the handedness of the individual in this distribution. However, in the static pool, several studies have been carried out which assess the possible causes of inequitable distribution of the charges, some according to the vision or adjoining space and according to influence of visual laterality. In our study we will observe the influence of the lateral lower limb preference in the distribution of the load on the sole of the foot, using three tests to assess the lateral dominance: shoot with precision, dynamic balance and static balance (Maupas et al. 2002). According to our results, lower limb lateral preference does not influence significantly the distribution of charges in the sole of the foot, however, we observe a tendency to increase the load/weight on the left limb in righthanded people (according to tests of balance dynamic and precision shot) and on the right limb in left handed people

*Carmen Mayolas Pi*, Adoración Villarroya Aparicio*, Joaquín Reverter Masia**

2011-01-01

80

Earth Inner Core Periodic Motion due to Pressure Difference Induced by Tidal Acceleration  

CERN Document Server

The inner structure of the earth is still a topic of discussion. Seismic measurements showed a structure of solid, liquid, solid which describes the mantle, outer core and inner core with the inner core in the center. The analysis of waveform doublets suggests now that the inner core is out of center and even of faster rotation than the mantel and crust. From the sum of Buoyancy and Gravity on the earth inner core, the position energy is plotted and together with the tangential tidal acceleration, it is derived that Earth Inner Core cannot be in a center position without additional force. The Earth Core System is explained as Hydrodynamic Bearing. The Eccentricities out of nutation due to the effects from the sun and moon are calculated as an approximation.

Wolf, M

2013-01-01

 
 
 
 
81

Measuring Center of Pressure Signals to Quantify Human Balance Using Multivariate Multiscale Entropy by Designing a Force Platform  

Directory of Open Access Journals (Sweden)

Full Text Available To assess the improvement of human body balance, a low cost and portable measuring device of center of pressure (COP), known as center of pressure and complexity monitoring system (CPCMS), has been developed for data logging and analysis. In order to prove that the system can estimate the different magnitude of different sways in comparison with the commercial Advanced Mechanical Technology Incorporation (AMTI) system, four sway tests have been developed (i.e., eyes open, eyes closed, eyes open with water pad, and eyes closed with water pad) to produce different sway displacements. Firstly, static and dynamic tests were conducted to investigate the feasibility of the system. Then, correlation tests of the CPCMS and AMTI systems have been compared with four sway tests. The results are within the acceptable range. Furthermore, multivariate empirical mode decomposition (MEMD) and enhanced multivariate multiscale entropy (MMSE) analysis methods have been used to analyze COP data reported by the CPCMS and compare it with the AMTI system. The improvements of the CPCMS are 35% to 70% (open eyes test) and 60% to 70% (eyes closed test) with and without water pad. The AMTI system has shown an improvement of 40% to 80% (open eyes test) and 65% to 75% (closed eyes test). The results indicate that the CPCMS system can achieve similar results to the commercial product so it can determine the balance.

Cheng-Wei Huang; Pei-Der Sue; Maysam F. Abbod; Bernard C. Jiang; Jiann-Shing Shieh

2013-01-01

82

Measuring center of pressure signals to quantify human balance using multivariate multiscale entropy by designing a force platform.  

UK PubMed Central (United Kingdom)

To assess the improvement of human body balance, a low cost and portable measuring device of center of pressure (COP), known as center of pressure and complexity monitoring system (CPCMS), has been developed for data logging and analysis. In order to prove that the system can estimate the different magnitude of different sways in comparison with the commercial Advanced Mechanical Technology Incorporation (AMTI) system, four sway tests have been developed (i.e., eyes open, eyes closed, eyes open with water pad, and eyes closed with water pad) to produce different sway displacements. Firstly, static and dynamic tests were conducted to investigate the feasibility of the system. Then, correlation tests of the CPCMS and AMTI systems have been compared with four sway tests. The results are within the acceptable range. Furthermore, multivariate empirical mode decomposition (MEMD) and enhanced multivariate multiscale entropy (MMSE) analysis methods have been used to analyze COP data reported by the CPCMS and compare it with the AMTI system. The improvements of the CPCMS are 35% to 70% (open eyes test) and 60% to 70% (eyes closed test) with and without water pad. The AMTI system has shown an improvement of 40% to 80% (open eyes test) and 65% to 75% (closed eyes test). The results indicate that the CPCMS system can achieve similar results to the commercial product so it can determine the balance.

Huang CW; Sue PD; Abbod MF; Jiang BC; Shieh JS

2013-01-01

83

Measuring center of pressure signals to quantify human balance using multivariate multiscale entropy by designing a force platform.  

Science.gov (United States)

To assess the improvement of human body balance, a low cost and portable measuring device of center of pressure (COP), known as center of pressure and complexity monitoring system (CPCMS), has been developed for data logging and analysis. In order to prove that the system can estimate the different magnitude of different sways in comparison with the commercial Advanced Mechanical Technology Incorporation (AMTI) system, four sway tests have been developed (i.e., eyes open, eyes closed, eyes open with water pad, and eyes closed with water pad) to produce different sway displacements. Firstly, static and dynamic tests were conducted to investigate the feasibility of the system. Then, correlation tests of the CPCMS and AMTI systems have been compared with four sway tests. The results are within the acceptable range. Furthermore, multivariate empirical mode decomposition (MEMD) and enhanced multivariate multiscale entropy (MMSE) analysis methods have been used to analyze COP data reported by the CPCMS and compare it with the AMTI system. The improvements of the CPCMS are 35% to 70% (open eyes test) and 60% to 70% (eyes closed test) with and without water pad. The AMTI system has shown an improvement of 40% to 80% (open eyes test) and 65% to 75% (closed eyes test). The results indicate that the CPCMS system can achieve similar results to the commercial product so it can determine the balance. PMID:23966184

Huang, Cheng-Wei; Sue, Pei-Der; Abbod, Maysam F; Jiang, Bernard C; Shieh, Jiann-Shing

2013-08-08

84

Studies on the high-pressure reaction of rare-earth sesquioxides with vanadium dioxide  

Energy Technology Data Exchange (ETDEWEB)

The reaction of rare-earth sesquioxides (Ln/sub 2/O/sub 3/) with vanadium dioxide (VO/sub 2/) at 1400sup(o)C and 50 kbar* * and 30 kbar was studied. Quadrivalent vanadium ions were reduced to the trivalent state, rare-earth vanadates (III) (LnVO/sub 3/) being obtained. For LnVO/sub 3/ a typical transformation of the ABO/sub 3/-type compounds, one from the aragonite-type to the perovskite-type via the vaterie- or calcite-type structure was observed with a decrease in the ionic radius of the rare-earth ions. The magnetic properties of the vaterite-type LnVO/sub 3/ were studied.

Shin-ike, T. (Osaka Dental Coll., Hirakata (Japan)); Adachi, G.; Shiokawa, J.; Shimada, M.; Koizumi, M.

1982-07-01

85

Argon surface wave discharges at medium pressure. Experiments and discussion on the energy balance  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Argon surface wave discharges, created at 210 MHz in capillary tubes have been studied at medium pressure, from 10 Torr to 200 Torr. Such discharges have been experimentally characterized ; the electron density profile along the plasma column, the effective electron neutral collision frequency v and...

Granier, A.; Gousset, G.; Leprince, P.; Marec, J.

86

Sc, Y, La-Lu. Rare earth elements. Vol. A6b. Y, La, and the lanthanoids. Geochemistry: Hydrosphere, atmosphere. Cosmo- and geochemical cycles. Balance  

Energy Technology Data Exchange (ETDEWEB)

The present volume 'Rare earth elements' A6b describes in its first part the origin, mode of occurrence, and behavior of Y and/or RE elements in the hydrosphere and atmosphere. Separately for marine and non-marine environments (surface, subsurface, mineral, and thermal waters), the behavior of RE (including Y) in the hydrosphere comprises especially the relationship between content/composition and the chemistry of water, and the processes acting during migration, removal, and precipitation are outlined; the influence of biological material is mentioned. Behavior of RE in the atmosphere involves mainly transport, regional differences, and temporal variations as well as removal by precipitation; the anthropogenic influence is only outlined. The second part of this volume treats, partly in a more summary manner, the cosmo- and geochemical cycles and the balance of Y and/or RE elements. The relationship between geodynamic position and type of magmatism, as well as the geochemical variations in the geospheres, especially mantle and crust of the earth, are described in greater detail. With 2 figs..

Sarbas, B.; Toepper, W.

1988-01-01

87

Calculated and experimental investigations of lateral earth pressure on a block pumphouse of the Zaporozh`E Nuclear Power Plant  

Energy Technology Data Exchange (ETDEWEB)

Results are set forth from a set of investigations (full-scale observations, laboratory experiments, and calculations by the finite-element method) to determine the lateral earth pressure on the underground part of a block pumphouse of the Zaporozh`e nuclear power plant. Laboratory investigations of sandy soils made it possible to confirm the validity of basic premises of a model of nonassociated plasticity and suggest a procedure for determining the model`s parameters. Comparison of the results of FEM calculations with data from full-scale observations showed that satisfactory correspondence is achieved only by taking into account strengthening and the sequence of erection of the structure and backfilling.

Bellendir, E.N.; Gol`din, A.L.; Gotlif, A.A.

1994-07-01

88

Pressure sensor-based tongue-placed electrotactile biofeedback for balance improvement--biomedical application to prevent pressure sores formation and falls.  

UK PubMed Central (United Kingdom)

We introduce the innovative technologies, based on the concept of "sensory substitution", we are developing in the fields of biomedical engineering and human disability. Precisely, our goal is to design, develop and validate practical assistive biomedical and/or technical devices and/or rehabilitating procedures for persons with disabilities, using artificial tongue-placed tactile biofeedback systems. Proposed applications are dealing with: (1) pressure sores prevention in case of spinal cord injuries (persons with paraplegia, or tetraplegia); and (2) balance control improvement to prevent fall in older and/or disabled adults. This paper describes the architecture and the functioning principle of these biofeedback systems and presents preliminary results of two feasibility studies performed on young healthy adults.

Vuillerme N; Chenu O; Pinsault N; Moreau-Gaudry A; Fleury A; Demongeot J; Payan Y

2007-01-01

89

Pressure sensor-based tongue-placed electrotactile biofeedback for balance improvement--biomedical application to prevent pressure sores formation and falls.  

Science.gov (United States)

We introduce the innovative technologies, based on the concept of "sensory substitution", we are developing in the fields of biomedical engineering and human disability. Precisely, our goal is to design, develop and validate practical assistive biomedical and/or technical devices and/or rehabilitating procedures for persons with disabilities, using artificial tongue-placed tactile biofeedback systems. Proposed applications are dealing with: (1) pressure sores prevention in case of spinal cord injuries (persons with paraplegia, or tetraplegia); and (2) balance control improvement to prevent fall in older and/or disabled adults. This paper describes the architecture and the functioning principle of these biofeedback systems and presents preliminary results of two feasibility studies performed on young healthy adults. PMID:18003410

Vuillerme, N; Chenu, O; Pinsault, N; Moreau-Gaudry, A; Fleury, A; Demongeot, J; Payan, Y

2007-01-01

90

Chemical pressure and hidden one-dimensional behavior in rare earth tri-telluride  

Energy Technology Data Exchange (ETDEWEB)

We report on the first optical measurements of the rare-earth tri-telluride charge-density-wave systems. Our data, collected over an extremely broad spectral range, allow us to observe both the Drude component and the single-particle peak, ascribed to the contributions due to the free charge carriers and to the charge-density-wave gap excitation, respectively. The data analysis displays a diminishing impact of the charge-density-wave condensate on the electronic properties with decreasing lattice constant across the rare-earth series. We propose a possible mechanism describing this behavior and we suggest the presence of a one-dimensional character in these two-dimensional compounds. We also envisage that interactions and umklapp processes might play a relevant role in the formation of the charge-density-wave state in these compounds.

Sacchetti, A.; Degiorgi, L.; /Zurich, ETH; Giamarchi, T.; /Geneva U.; Ru, N.; Fisher, I.R.; /Stanford U., Geballe Lab.

2009-12-14

91

The pressure dilation of a deep, jointed region of the earth  

Energy Technology Data Exchange (ETDEWEB)

A series of pressurization tests of a 3.5-km deep body of jointed crystalline rock has shown that both the pressure deformation (i.e., dilation) of the region and the boundary permeation are nonlinear functions of the effective stress. This is because the apertures for both the joints and microcracks are strong functions of the effective normal stress acting to close them. For a surface pressure increase from zero to 7.5 MPa, the fluid storage in the natural joints and microcracks in this 0.3 km{sup 3} volume of rock increased by 1470 m{sup 3}. The corresponding increase in fluid storage between 7.5 and 15 MPa was 1090 m{sup 3}. However, even at a surface pressure level of 15 MPa, the permeation loss rate from this large volume of rock is only 0.3 l/s after six months of pressure maintenance. Using transient nonlinear numerical modeling, it is shown that the pressure-dependent fracture permeability model of Gangi, and the fracture porosity equivalent, adequately represent the measured permeability and porosity data obtained to date from this continuing series of pressurization experiments.

Brown, D.W.; Robinson, B.A.

1990-03-05

92

Irregular dust devil pressure drops on Earth and Mars: Effect of cycloidal tracks  

Science.gov (United States)

In a survey of dust devil activity at a desert playa using continuous monitoring by a pressure logger, we have detected a number of pressure drops with complex structures: simple and symmetric drops make up only 25-30% of the total. In contrast to the simple, symmetric single-dip profiles expected for single-cell vertical vortices gliding past the pressure sensor, many profiles have an asymmetric shape, double dips, or 'shoulders' where a broad shallow dip is superposed on a narrow deeper one. A double dip in Mars Phoenix data was attributed in prior work to a near-simultaneous encounter with two dust devils, while laboratory experiments with two-cell vortices find a local peak in pressure at the center, also yielding a double dip in a transect profile. However, we suggest instead that a likely explanation for many complex pressure profiles measured in the field and on Mars is in fact the trochoidal path of a dust devil across the terrain, rather than the straight-line constant-speed path usually assumed. Images of the Martian surface show that many dust devil tracks have such a trochoidal or cycloidal path, which can be parametrically described. A model of the pressure profile driven by this parametric path description can reproduce observations.

Lorenz, Ralph D.

2013-02-01

93

Earth in the balance. Ecology and the human spirit; Urgence Planete Terre. L'esprit humain face a la crise ecologique  

Energy Technology Data Exchange (ETDEWEB)

This book is the translation of the original American edition 'earth in the balance'. When Earth in the Balance first came out, it caused quite a stir and for good reason. It convincingly makes the case that a crisis of epidemic proportions is nearly upon us and that if the world does not get its act together soon and agree to some kind of 'Global Marshall Plan' to protect the environment, we're all up a polluted creek without a paddle. Myriad plagues are upon us, but the worst include the loss of biodiversity, the depletion of the ozone layer, the slash-and-burn destruction of rain forests, and the onset of global warming. None of this is new, of course, nor was it new in 1992. But most environmentalists will still get a giddy feeling reading such a call to action as written by a prominent politician. The book is arranged into three sections: the first describes the plagues; the second looks at how we got ourselves into this mess; and the final chapters present ways out. Gore gets his points across in a serviceable way, though he could have benefited from a firmer editor's hand; at times the analogies are arcane and the pacing is odd kind of like a Gore speech that climaxes at weird points and then sinks just as the audience is about to clap. Still, at the end you understand what's been said. Gore believes that if we apply some American ingenuity, the twin engines of democracy and capitalism can be rigged to help us stabilize world population growth, spread social justice, boost education levels, create environmentally appropriate technologies, and negotiate international agreements to bring us back from the brink. For example, a worldwide shift to clean, renewable energy sources would create huge economic opportunities for companies large and small to design, build, and maintain solar panels, wind turbines, fuel cells, and other eco friendly innovations.

Al Gore

2007-07-01

94

Maternal Prepregnancy Body Mass Index and Their Children's Blood Pressure and Resting Cardiac Autonomic Balance at Age 5 to 6 Years.  

UK PubMed Central (United Kingdom)

Adverse intrauterine conditions can program hypertension. Because one of the underlying mechanisms is thought to be cardiac autonomic balance, we investigated the association between prepregnancy body mass index (BMI) and blood pressure and indicators of the autonomic balance in the child at age 5 to 6 years. Also investigated was whether these associations were mediated by standardized birth weight and child BMI. Pregnant women (n=3074) participating in the Amsterdam Born Children and their Development study completed a questionnaire at gestational week 14. At age 5 to 6 years, offspring's sympathetic drive (pre-ejection period), parasympathetic drive (respiratory sinus arrhythmia), and heart rate were measured by electrocardiography and impedance cardiography at rest. Blood pressure was assessed simultaneously. After adjusting for possible maternal/offspring confounders, prepregnancy BMI was positively linearly associated with diastolic blood pressure (?=0.11 mm Hg; 95% confidence interval, 0.05-0.17), systolic blood pressure (?=0.14 mm Hg; 95% confidence interval, 0.07-0.21), but not with heart rate, sympathetic or parasympathetic drive. After adding birth weight and child BMI to the model, the independent effect size of prepregnancy body mass index on systolic blood pressure (?=0.07 mm Hg; 95% confidence interval, 0.00-0.14) and diastolic blood pressure (?=0.07 mm Hg; 95% confidence interval, 0.01-0.13) decreased by ?50%. Birth weight did not mediate these relationships, but was independently and negatively associated with blood pressure. Child BMI was positively associated with blood pressure and partly mediated the association between prepregnancy BMI and blood pressure. In conclusion, higher prepregnancy BMI is associated with higher blood pressure in the child (aged 5-6 years) but does not seem to be attributable to early alterations in resting cardiac autonomic balance. Child BMI, but not birth weight, mediated the association between prepregnancy BMI and blood pressure.

Gademan MG; van Eijsden M; Roseboom TJ; van der Post JA; Stronks K; Vrijkotte TG

2013-09-01

95

SMALL-SCALE PRESSURE-BALANCED STRUCTURES DRIVEN BY OBLIQUE SLOW MODE WAVES MEASURED IN THE SOLAR WIND  

Energy Technology Data Exchange (ETDEWEB)

Recently, small-scale pressure-balanced structures (PBSs) were identified in the solar wind, but their formation mechanism remains unclear. This work aims to reveal the dependence of the properties of small-scale PBSs on the background magnetic field (B{sub 0}) direction and thus to corroborate the in situ mechanism that forms them. We analyze the plasma and magnetic field data obtained by WIND in the quiet solar wind at 1 AU. First, we use a developed moving-average method to obtain B{sub 0}(s, t) for every temporal scale (s) at each time moment (t). By wavelet cross-coherence analysis, we obtain the correlation coefficients between the thermal pressure P{sub th} and the magnetic pressure P{sub B}, distributing against the temporal scale and the angle {theta}{sub xB} between B{sub 0}(s, t) and Geocentric Solar Ecliptic coordinates (GSE)-x. We note that the angle coverage of a PBS decreases with shorter temporal scale, but the occurrence of the PBSs is independent of {theta}{sub xB}. Suspecting that the isolated small PBSs are formed by compressive waves in situ, we continue this study by testing the wave modes forming a small-scale PBS with B{sub 0}(s, t) quasi-parallel to GSE-x. As a result, we identify that the cross-helicity and the compressibility attain values for a slow mode from theoretical calculations. The wave vector is derived from minimum variance analysis. Besides, the proton temperatures obey T < T{sub Parallel-To} derived from the velocity distribution functions, excluding a mirror mode, which is the other candidate for the formation of PBSs in situ. Thus, a small-scale PBS is shown to be driven by oblique, slow-mode waves in the solar wind.

Yao Shuo [School of Geophysics and Information Technology, China University of Geosciences (Beijing), Beijing 100083 (China); He, J.-S.; Tu, C.-Y.; Wang, L.-H. [Department of Geophysics, Peking University, Beijing (China); Marsch, E., E-mail: yaoshuo@cugb.edu.cn [Christian Albrechts University at Kiel, Kiel (Germany)

2013-09-01

96

Magnetism in rare earth Co{sub 2} compounds under high pressures  

Energy Technology Data Exchange (ETDEWEB)

We have studied electrical resistivity anomalies connected with magnetism in RECo{sub 2} (RE=Nd,Tb,Er,Ho) compounds in pressures up to 8 GPa. At ambient pressure the former two compounds exhibit a second order magnetic phase transition (SOMPT) at T{sub C,} whereas a first order magnetic phase transition (FOMPT) is observed in the latter two. Although T{sub C} decreases with pressure in all four compounds, the T{sub C}(P) dependence for NdCo{sub 2} and TbCo{sub 2} differs considerably from this for HoCo{sub 2} and ErCo{sub 2}. For the latter two, T{sub c} vs P data deviate dramatically from the initial linear dependence above a critical pressure P{sub c} to become almost pressure independent at higher pressures. We propose that this is reflecting the loss of Co metamagnetism that is also indicated by the vanishing resistivity drop at T{sub c} for P{gt}4GPa and by the change from a FOMPT to a SOMPT. A scenario is discussed assuming that for P{gt}P{sub c} the projected Co3d density of states at E{sub F} decreases. Hence the Co moment collapses because the RE-Co-RE exchange channel becomes ineffective to induce the itinerant 3d electron metamagnetism. The localized RE moments, however, order at a {open_quotes}residual{close_quotes} T{sub C} due to the persisting Ruderman{endash}Kittel{endash}Kasuya{endash}Yosida-type exchange interaction. For NdCo{sub 2} and TbCo{sub 2} the T{sub c} values decrease with pressure by an exponential law but remain rather high in the highest applied pressures. Results of first-principles electronic structure calculations using the full-potential linearized augmented plane wave method are presented for HoCo{sub 2} and NdCo{sub 2} compounds, as well. {copyright} 2001 American Institute of Physics.

Syshchenko, O.; Sechovsky, V.; Divis, M.; Fujita, T.; Hauser, R.; Fujii, H.

2001-06-01

97

Upper-bound solutions of three-dimensional passive earth pressures  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents a novel approach to the determination of passive soil pressures: using the upper-bound method within the framework of limit analysistheory. It is based on a three-dimensional, kinematically admissible, rotational, hyperbolical failure mechanism. The failure mechanism is composed ...

Škrabl, Stanislav; Macuh, Borut

98

High pressure polymorphism of rare earth sulfidefluorides LnSF (Ln: Er, Yb, Lu)  

Energy Technology Data Exchange (ETDEWEB)

The sulfidefluorides LnSF with Ln = Er, Yb, Lu undergo a high pressure transformation from the ..beta..-YSF- to a PbFCl-type structure. The structures involved and a proposed reaction mechanism are explained in terms of a topological description.

Beck, H.P.; Strobel, C.

1985-12-01

99

Effect of Chemical Pressure on the Charge Density Wave Transition in Rare-earth Tritellurides RTe_3  

CERN Multimedia

The charge density wave transition is investigated in the bi-layer family of rare earth tritelluride RTe_3 compounds (R = Sm, Gd, Tb, Dy, Ho, Er, Tm) via high resolution x-ray diffraction and electrical resistivity. The transition temperature T_{CDW} increases monotonically with increasing lattice parameter by an extraordinarily large amount, from 244(3) K for TmTe_3 to 416(3) K for SmTe_3. It is suggested that this behavior, and the observation of a secondary transition for the heaviest members of the series, is intimately linked to the effect of chemical pressure on the degree of bilayer splitting of the Fermi surface.

Ru, N; Shin, K Y; Toney, M F; Fisher, I R

2006-01-01

100

Effect of chemical and hydrostatic pressures on structural and magnetic properties of rare-earth orthoferrites: a first-principles study.  

UK PubMed Central (United Kingdom)

The dependence of structural and magnetic properties of rare-earth orthoferrites (in their Pbnm ground state) on the rare-earth ionic radius is systematically investigated from first principles. The effects of this 'chemical pressure' on lattice constants, Fe-O bond lengths, Fe-O-Fe bond angles and Fe-O bond length splittings are all well reproduced by these ab initio calculations. The simulations also offer novel predictions (on tiltings of FeO6 octahedra, cation antipolar displacements and weak magnetization) to be experimentally checked. In particular, the weak ferromagnetic moment of rare-earth orthoferrites is predicted to be a linear function of the rare-earth ionic radius. Finally, the effects of applying hydrostatic pressure on structural and magnetic behavior of SmFeO3 is also studied. It is found that, unlike previously assumed, hydrostatic pressure typically generates changes in physical properties that are quantitatively and even qualitatively different from those associated with the chemical pressure.

Zhao HJ; Ren W; Yang Y; Chen XM; Bellaiche L

2013-10-01

 
 
 
 
101

Estudio experimental del empuje sobre estructuras de contención en suelos reforzados con geomallas Experimental study of the lateral earth pressure on retaining structures in soils reinforced with geogrids  

Directory of Open Access Journals (Sweden)

Full Text Available Este artículo presenta un estudio experimental de la variación de las tensiones de empuje sobre una pared que soporta un suelo reforzado con geomallas. Para ello se utilizó un equipo diseñado y construido especialmente para ejecutar ensayos de empuje bajo condiciones de deformación plana. Se describe el equipo de ensayo y los instrumentos de medición, así como el suelo y la preparación de las muestras de arena y la geomalla utilizada. En la primera etapa de la investigación se ensayan muestras sin reforzar y se comparan los resultados con aquellos provenientes de las teorías clásicas de empuje. Posteriormente se presentan los resultados de ensayos de empuje en suelo reforzado con una, dos, tres y cuatro geomallas. Se concluye que la incorporación de geomallas como refuerzo en el suelo disminuye el empuje ejercido por el suelo sobre la estructura de contención. Esta disminución del empuje es de aproximadamente un 25% cuando se usa una geomalla, un 50% con dos o tres geomallas y de un 75% con cuatro geomallas para los espaciamientos, sobrecargas e incremento de desplazamientos usados. Resultó posible identificar que la distribución de la tensión de empuje con la profundidad no sólo no sigue la variación triangular sino que se desarrollan arcos de tensiones en el suelo entre las geomallas.This article presents an experimental study on the variation with depth of the stresses due to lateral earth pressure on a wall retaining a soil reinforced with geogrids. To this end, an apparatus was designed and constructed especially tailored for performing lateral earth pressure tests under plain strain conditions. The experimental apparatus and the measurement instruments as well as the soil and the sample preparation and the geogrids used, are described. In a first stage of research, samples without reinforcing are tested and the results are compared with those from classic earth pressure theories. Subsequently, results from lateral earth pressure tests in soils reinforced with one, two, three and four geogrids are presented. It is concluded that the inclusion of geogrids as soil reinforcement reduces the earth pressure on the retaining structure. This lateral earth pressure reduction is approximately of 25% when one geogrid is used, 50% with two or three geogrids and 75% with four geogrids for the spacing, surcharges and displacement increments used. It was possible to identify that the lateral earth pressure distribution with depth not only does not follow a triangular variation, but it develops stress arching in the soil and between the geogrids.

Lissette Ruiz-Tagle; Felipe Villalobos

2011-01-01

102

3-D Force-balanced Magnetospheric Configurations  

Energy Technology Data Exchange (ETDEWEB)

The knowledge of plasma pressure is essential for many physics applications in the magnetosphere, such as computing magnetospheric currents and deriving magnetosphere-ionosphere coupling. A thorough knowledge of the 3-D pressure distribution has however eluded the community, as most in-situ pressure observations are either in the ionosphere or the equatorial region of the magnetosphere. With the assumption of pressure isotropy there have been attempts to obtain the pressure at different locations by either (a) mapping observed data (e.g., in the ionosphere) along the field lines of an empirical magnetospheric field model or (b) computing a pressure profile in the equatorial plane (in 2-D) or along the Sun-Earth axis (in 1-D) that is in force balance with the magnetic stresses of an empirical model. However, the pressure distributions obtained through these methods are not in force balance with the empirical magnetic field at all locations. In order to find a global 3-D plasma pressure distribution in force balance with the magnetospheric magnetic field, we have developed the MAG-3D code, that solves the 3-D force balance equation J x B = (upside-down delta) P computationally. Our calculation is performed in a flux coordinate system in which the magnetic field is expressed in terms of Euler potentials as B = (upside-down delta) psi x (upside-down delta) alpha. The pressure distribution, P = P(psi,alpha), is prescribed in the equatorial plane and is based on satellite measurements. In addition, computational boundary conditions for y surfaces are imposed using empirical field models. Our results provide 3-D distributions of magnetic field and plasma pressure as well as parallel and transverse currents for both quiet-time and disturbed magnetospheric conditions.

Sorin Zaharia; C.Z. Cheng; K. Maezawa

2003-02-10

103

3-D Force-balanced Magnetospheric Configurations  

International Nuclear Information System (INIS)

[en] The knowledge of plasma pressure is essential for many physics applications in the magnetosphere, such as computing magnetospheric currents and deriving magnetosphere-ionosphere coupling. A thorough knowledge of the 3-D pressure distribution has however eluded the community, as most in-situ pressure observations are either in the ionosphere or the equatorial region of the magnetosphere. With the assumption of pressure isotropy there have been attempts to obtain the pressure at different locations by either (a) mapping observed data (e.g., in the ionosphere) along the field lines of an empirical magnetospheric field model or (b) computing a pressure profile in the equatorial plane (in 2-D) or along the Sun-Earth axis (in 1-D) that is in force balance with the magnetic stresses of an empirical model. However, the pressure distributions obtained through these methods are not in force balance with the empirical magnetic field at all locations. In order to find a global 3-D plasma pressure distribution in force balance with the magnetospheric magnetic field, we have developed the MAG-3D code, that solves the 3-D force balance equation J x B = (upside-down delta) P computationally. Our calculation is performed in a flux coordinate system in which the magnetic field is expressed in terms of Euler potentials as B = (upside-down delta) psi x (upside-down delta) alpha. The pressure distribution, P = P(psi,alpha), is prescribed in the equatorial plane and is based on satellite measurements. In addition, computational boundary conditions for y surfaces are imposed using empirical field models. Our results provide 3-D distributions of magnetic field and plasma pressure as well as parallel and transverse currents for both quiet-time and disturbed magnetospheric conditions

2003-01-01

104

The effect of temperature and pressure on optical absorption spectra of transition zone minerals - Implications for the radiative conductivity of the Earth's interior  

Science.gov (United States)

Optical absorption spectra of high-pressure minerals can be used as indirect tools to calculate radiative conductivities of the Earth’s interior [e.g., 1]. Recent high-pressure studies imply that e.g. ringwoodite, ?-(Mg,Fe)2SiO4, does not become opaque in the near infrared and visible region, as previously assumed, but remains transparent to 21.5 GPa [2]. Therefore, it has been concluded that radiative heat transfer does not necessarily become blocked at high pressures of the mantle and ferromagnesian minerals actually might contribute to the heat flow in the Earth’s interior [2]. However, experimental results on temperature effects on radiative heat transfer are not available. We studied the effect of both, pressure and temperature, on the optical absorption of hydrous Fe-bearing ringwoodite, ?-(Mg,Fe)2SiO4, and hydrous Fe-bearing wadsleyite, ?-(Mg,Fe)2SiO4, which are the main components of the Earth’s transition zone. Gem-quality single-crystals were synthesized at 18 GPa and 1400 °C in a 5000t multianvil apparatus. Crystals were analyzed by Mössbauer and Raman spectroscopy, electron microprobe analysis and single-crystal X-ray diffraction. For optical absorption measurements in the IR - VIS - UV spectral range (400 - 50000 cm-1) 50 µm sized single-crystals of ringwoodite and wadsleyite were double polished to thicknesses of 13 µm and 18 µm, respectively, and loaded in resistively heated diamond-anvil cells with argon as pressure medium. After taking measurements at high pressure and room temperature, ringwoodite was studied at 26 GPa up to 650 °C and wadsleyite spectra were recorded at 16 GPa up to 450 °C. At ambient pressure the absorption spectrum of ringwoodite reveals a crystal field band (Fe2+) at 12075 cm-1, an intervalence charge transfer band (Fe2+ to Fe3+) at 16491 cm-1, and an absorption edge due to ligand-metal charge transfer close to 30000 cm-1. The wadsleyite spectrum is characterized by a similar absorption edge in the VIS-UV range and by two broad bands at ˜10000 cm-1 and ˜15000 cm-1, which are crystal field and intervalence charge transfer band, respectively. With increasing pressure the absorption spectra of both compositions change uniformly, crystal field and intervalence charge transfer bands continuously shift to higher frequencies. This has been observed for ringwoodite [2] but is contrary to earlier presumptions for wadsleyite [3]. Here, we present radiative conductivities calculated from high-pressure/high-temperature optical absorption spectra. Our results support earlier assumptions that transition zone minerals might contribute to radiative heat transfer in the Earth’s mantle. References: [1] Goncharov et al. (2008), McGraw Yearbook Sci. Tech., 242-245. [2] Keppler & Smyth (2005), Am. Mineral., 90 1209-1212. [3] Ross (1997), Phys. Chem. Earth, 22 113-118.

Thomas, S.; Jacobsen, S. D.; Bina, C. R.; Goncharov, A. F.; Frost, D. J.; McCammon, C. A.

2010-12-01

105

Earth materials and earth dynamics  

Energy Technology Data Exchange (ETDEWEB)

In the project ''Earth Materials and Earth Dynamics'' we linked fundamental and exploratory, experimental, theoretical, and computational research programs to shed light on the current and past states of the dynamic Earth. Our objective was to combine different geological, geochemical, geophysical, and materials science analyses with numerical techniques to illuminate active processes in the Earth. These processes include fluid-rock interactions that form and modify the lithosphere, non-linear wave attenuations in rocks that drive plate tectonics and perturb the earth's surface, dynamic recrystallization of olivine that deforms the upper mantle, development of texture in high-pressure olivine polymorphs that create anisotropic velocity regions in the convecting upper mantle and transition zone, and the intense chemical reactions between the mantle and core. We measured physical properties such as texture and nonlinear elasticity, equation of states at simultaneous pressures and temperatures, magnetic spins and bonding, chemical permeability, and thermal-chemical feedback to better characterize earth materials. We artificially generated seismic waves, numerically modeled fluid flow and transport in rock systems and modified polycrystal plasticity theory to interpret measured physical properties and integrate them into our understanding of the Earth. This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL).

Bennett, K; Shankland, T. [and others

2000-11-01

106

Behavior of the earth retaining structures acted upon by unsymmetrical lateral pressure and a method of analyzing this behavior. Hen'atsu ga sayosuru yamatome kako no jissoku kyodo to sono kaiseki  

Energy Technology Data Exchange (ETDEWEB)

Sudden change in the behavior of earth retaining structures due to unsymmetrical lateral pressure of hydraulic pressure which increased rapidly by unusually heavy rainfall experienced in Tokyo during excavation work is investigated based on the actually measured data. The actually measured behavior of the earth retaining structure under this unsymmetrical lateral pressure is investigated firstly in relation to the water pressure increase at the time of the unusually heavy rainfall. The behavior of this earth retaining structure is analyzed by the integrated analytical method for opposing retaining walls proposed in this report to investigate the actual behavior by comparing with the analyzed values. The unsymmetrical lateral pressure acting upon the earth retaining structure is generally studied in the area with a slope or ground surface having different elevation, but it is made clear in this report that water level increase at the time of unusually heavy rainfall also acts on the earth retaining structure as unsymmetrical lateral pressure. As a result, it is found that excessive deformation and strain are also produced in the earth retaining wall. In addition, The above-mentioned behavior of the earth retaining structure is elucidated well by the integrated analytical method for the opposing earth retaining walls presented in this report. 13 refs., 21 figs., 1tab.

Miyazaki, Y. (Obayashi Corp., Osaka (Japan). Technical Research Inst.); Kazama, S. (Waseda Univ., Tokyo (Japan). Science and Engineering Research Lab.); Murata, J. (Waseda Univ., Tokyo (Japan). Graduate School)

1992-09-30

107

Mecanismos fisiopatológicos del desbalance glomérulo-tubular en la hipertensión arterial/ Pathophysiological mechanisms of the lack of glomerulus-tubule balance in arterial high blood pressure  

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish Las actuales tendencias e hipótesis para interpretar los mecanismos etiopatogénicos de la hipertensión arterial esencial, involucran al sistema renal como mecanismo preponderante en la regulación a largo plazo de la presión arterial y la existencia en él de algún fenómeno que puede conllevar a desbalance glomérulo-tubular, con preponderancia tubular Aunque el análisis de este último hecho no ha sido como tal abordado en la patogénesis del síndrome hipertensiv (more) o. Con el objetivo de interpretar el papel del desbalance glomérulo-tubular, con preponderancia tubular en la fisiopatología de la hipertensión arterial como fenómeno en el que confluyen múltiples mecanismos fisiopatológicos renales ya descritos, se revisaron estos últimos, de forma integrada y su relación causal con el desbalance glomérulo-tubular, con preponderancia tubular. La preponderancia tubular, punto común de los mecanismos que se discuten, favorece la disminución de la excreción fraccional de Na+, la retención hidrosalina y la elevación de la presión arterial. Abstract in english The current trends and hypotheses to know the etiopathogenesis mechanisms of the essential arterial high blood pressure involved the renal system as a prevailing mechanism in the long-term regulation of arterial pressure and the existence in it of some phenomenon that could lead to a glomerulus-tubule lack of balance with tubular preponderance. Although the analysis of this latter fact, has not been approached as such in pathogenesis of hypertensive syndrome. With the aim (more) of to interpret the role of glomerulus-tubule lack of balance with tubular preponderance in pathophysiology of arterial high blood pressure as a phenomenon in which converging multiple renal pathophysiological mechanisms already described, these latter were reviewed in a integrated way and its causal relation with the above mentioned lack of balance with tubular preponderance. This preponderance, a common point of discussed mechanisms, favors the decrease of a fractional releasing of Na+, the hydrosaline retention and the raise of arterial pressure.

Barber Fox, María Ofelia; Galvizu Díaz, Katiana; Pérez Ramos, Aydelín; Fox Pascual, María Ofelia

2010-12-01

108

Experimental study on thermal-hydraulic behaviors of a pressure balanced coolant injection system for a passive safety light water reactor JPSR  

Energy Technology Data Exchange (ETDEWEB)

A conceptual design study of a passive safety light water reactor JPSR has been performed at Japan Atomic Energy Research Institute JAERI. A pressure balanced coolant injection experiment has been carried out, with an objective to understand thermal-hydraulic characteristics of a passive coolant injection system which has been considered to be adopted to JPSR. This report summarizes experimental results and data recorded in experiment run performed in FY. 1993 and 1994. Preliminary experiments previously performed are also briefly described. As the results of the experiment, it was found that an initiation of coolant injection was delayed with increase in a subcooling in the pressure balance line. By inserting a separation device which divides the inside of core make-up tank (CMT) into several small compartments, a diffusion of a high temperature region formed just under the water surface was restrained and then a steam condensation was suppressed. A time interval from an uncovery of the pressure balance line to the initiation of the coolant injection was not related by a linear function with a discharge flow rate simulating a loss-of-coolant accident (LOCA) condition. The coolant was injected intermittently by actuation of a trial fabricated passive valve actuated by pressure difference for the present experiment. It was also found that the trial passive valve had difficulties in setting an actuation set point and vibrations noises and some fraction of the coolant was remained in CMT without effective use. A modification was proposed for resolving these problems by introducing an anti-closing mechanism. (author)

Satoh, Takashi; Watanabe, Hironori; Araya, Fumimasa; Nakajima, Katsutoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Iwamura, Takamichi; Murao, Yoshio

1998-02-01

109

Separation of rare earth, nuclear-fuel burn-up monitors in the 10-9 mole range by high-pressure liquid chromatography with UV-detection  

International Nuclear Information System (INIS)

Anion-exchange chromatography of the rare earth (Sm, Nd, Pr, Ce) ions in methanol-nitric acid-water media is performed using high-pressure liquid chromatography. The separation method is especially designed for determination of 148Nd in nuclear fuel cycle in order to find precise burn-up values. While commonly used for rare earth separation at low pressure and hence low flow rate, this separation system has not been described using HPLC. The samples injected on the column contain typically 10 nmole of the nitrates of Sm, Nd, Pr and Ce. Furthermore, some experiments with a large excess of uranyl nitrate were carried out in order to simulate the conditions in solutions of irradiated nuclear fuel. After equilibration of the column to the desired elution composition, 20-25x?l of sample was injected. The sample concentration was typically 4x10-4 M for the ions of Sm, Pr, Nd and Ce. In the separations with added uranyl nitrate, the uranium concentrations were varied 1-125 times the concentrations of the individual rare earths. By adjusting the pressure between 300 and 600 psi, the flow rate was kept in the range 0.5-1.0 cm3/min. As no changes in the separation were observed as a result of this variation, 1.0 cm3/min was used throughout. The high-pressure liquid chromatography method presented here is very fast, gives high resolutions, and enables collection of selected fractions containing nmoles of rare earth by UV monitoring at 280 nm of the eluate. (T.G.)

1978-01-01

110

Structural changes and pressure-induced amorphization in rare earth titanates RE2Ti2O7 (RE: Gd, Sm) with pyrochlore structure  

Science.gov (United States)

Structural changes of pyrochlore titanates, Sm2Ti2O7 and Gd2Ti2O7, at high pressures were studied by in situ Raman scattering and X-ray diffraction (XRD) methods. The Raman experiments revealed that RE2Ti2O7 lost pyrochlore structural character at pressures of 40 GPa and 38 GPa for RE = Sm and Gd, respectively. However, XRD results found that they were only partially amorphized up to 51 GPa. The crystalline phase at high pressure is a distorted pyrochlore - the anions have lost long-range order while the rare earth ions still keep some ordering. Both of the pyrochlores became completely amorphous after releasing pressure from 51 GPa.

Zhang, F. X.; Saxena, S. K.

2005-09-01

111

Postural balance in low back pain patients : Intra-session reliability of center of pressure on a portable force platform and of the one leg stand test  

DEFF Research Database (Denmark)

Low back pain (LBP) patients have poorer postural control compared to healthy controls, and the importance of assessing and addressing balance is a matter of debate. In the clinic, balance is often tested by means of the one leg stand test (OLST) while research often employs center of pressure (CoP) on a force platform. Portable force platforms might be of clinical relevance, but their reliability for LBP patients in a clinical setting has not been demonstrated. As LBP patients are more dependent on vision compared to healthy controls, the ratio of tests performed with eyes open and eyes closed (Romberg Ratio) might be of clinical interest. This study aimed to assess postural balance in LBP patients by analyzing intra-session reliability of CoP parameters on a portable force platform, the Romberg Ratio, and the OLST. Furthermore, we aimed to determine whether CoP parameters and OLST measure identical aspects of postural stability. We examined 49 LBP patients and found acceptable reliability of the CoP parameters' trace length and velocity, whereas reliability regarding C90 area, the Romberg Ratio, and the OLST was poor. Correlations between the CoP parameters and OLST were insignificant. Reliability of trace length and velocity is acceptable and can be used as parameters when assessing CoP in LBP patients.

Maribo, Thomas; Stengaard-Pedersen, Kristian

2011-01-01

112

Postural balance in low back pain patients: Intra-session reliability of center of pressure on a portable force platform and of the one leg stand test  

DEFF Research Database (Denmark)

Low back pain (LBP) patients have poorer postural control compared to healthy controls, and the importance of assessing and addressing balance is a matter of debate. In the clinic, balance is often tested by means of the one leg stand test (OLST) while research often employs center of pressure (CoP) on a force platform. Portable force platforms might be of clinical relevance, but their reliability for LBP patients in a clinical setting has not been demonstrated. As LBP patients are more dependent on vision compared to healthy controls, the ratio of tests performed with eyes open and eyes closed (Romberg Ratio) might be of clinical interest. This study aimed to assess postural balance in LBP patients by analyzing intra-session reliability of CoP parameters on a portable force platform, the Romberg Ratio, and the OLST. Furthermore, we aimed to determine whether CoP parameters and OLST measure identical aspects of postural stability. We examined 49 LBP patients and found acceptable reliability of the CoP parameters' trace length and velocity, whereas reliability regarding C90 area, the Romberg Ratio, and the OLST was poor. Correlations between the CoP parameters and OLST were insignificant. Reliability of trace length and velocity is acceptable and can be used as parameters when assessing CoP in LBP patients.

Maribo, Thomas; Stengaard-Pedersen, Kristian

2011-01-01

113

Forensic analysis of crib mattress properties on pediatric CPR quality--can we balance pressure reduction with CPR effectiveness?  

UK PubMed Central (United Kingdom)

INTRODUCTION: Single mode, pressure reduction (PR) crib mattresses are increasingly employed in hospitals to prevent skin injury and infection. However, single mode PR mattresses risk large mattress deflection during CPR chest compressions, potentially leading to inadequate chest compressions. HYPOTHESIS: New, dual mode PR crib mattress technology provides less mattress deflection during chest compressions (CCs) with similar PR characteristics for prevention of skin injury. METHODS: Epochs of 50 high-quality CCs (target sternum-spine compression depth ? 38 mm) guided by real-time force/deflection sensor (FDS) feedback were delivered to CPR manikin with realistic CC characteristics on two PR crib mattresses for four conditions: (1) single mode+backboard; (2) dual mode+backboard; (3) single mode-no backboard; and (4) dual mode-no backboard. Mattress displacement was measured using surface reference accelerometers. Mattress displacement ? 5 mm was prospectively defined as minimal clinically important difference. PR qualities of both mattresses were assessed by tissue interface pressure mapping. RESULTS: During simulated high quality CC, single mode had significantly more mattress displacement compared to dual mode (mean difference 16.5 ± 1.4mm, p<0.0001) with backboard. This difference was greater when no backboard was used (mean difference 31.7 ± 1.5mm, p<0.0001). Both single mode and dual mode met PR industry guidelines (mean surface pressure <50 mm Hg). CONCLUSIONS: Chest compressions delivered on dual mode pressure reduction crib mattresses resulted in substantially smaller mattress deflection compared to single mode pressure reduction mattresses. Skin pressure reduction qualities of dual mode pressure reduction crib mattress were maintained. We recommend that backboards continue to be used in order to mitigate mattress deflection during CPR on soft mattresses.

Niles DE; Maltese MR; Nishisaki A; Seacrist T; Leffelman J; Hutchins L; Schneck N; Sutton RM; Arbogast KB; Berg RA; Nadkarni VM

2013-08-01

114

Education and Outreach Programs Offered by the Center for High Pressure Research and the Consortium for Materials Properties Research in Earth Sciences  

Science.gov (United States)

Major research facilities and organizations provide an effective venue for developing partnerships with educational organizations in order to offer a wide variety of educational programs, because they constitute a base where the culture of scientific investigation can flourish. The Consortium for Materials Properties Research in Earth Sciences (COMPRES) conducts education and outreach programs through the Earth Science Educational Resource Center (ESERC), in partnership with other groups that offer research and education programs. ESERC initiated its development of education programs in 1994 under the administration of the Center for High Pressure Research (CHiPR), which was funded as a National Science Foundation Science and Technology Center from 1991 to 2002. Programs developed during ESERC's association with CHiPR and COMPRES have targeted a wide range of audiences, including pre-K, K-12 students and teachers, undergraduates, and graduate students. Since 1995, ESERC has offered inquiry-based programs to Project WISE (Women in Science and Engineering) students at a high school and undergraduate level. Activities have included projects that investigated earthquakes, high pressure mineral physics, and local geology. Through a practicum known as Project Java, undergraduate computer science students have developed interactive instructional tools for several of these activities. For K-12 teachers, a course on Long Island geology is offered each fall, which includes an examination of the role that processes in the Earth's interior have played in the geologic history of the region. ESERC has worked with Stony Brook's Department of Geosciences faculty to offer courses on natural hazards, computer modeling, and field geology to undergraduate students, and on computer programming for graduate students. Each summer, a four-week residential college-level environmental geology course is offered to rising tenth graders from the Brentwood, New York schools in partnership with Stony Brook's Department of Technology and Society. During the academic year, a college-level Earth science course is offered to tenth graders from Sayville, New York. In both programs, students conduct research projects as one of their primary responsibilities. In collaboration with the Museum of Long Island Natural Sciences on the Stony Brook campus, two programs have been developed that enable visiting K-12 school classes to investigate earthquakes and phenomena that operate in the Earth's deep interior. From 1997 to 1999, the weekly activity-based Science Enrichment for the Early Years (SEEY) program, focusing on common Earth materials and fundamental Earth processes, was conducted at a local pre-K school. Since 2002, ESERC has worked with the Digital Library for Earth System Education (DLESE) to organize the Skills Workshops for their Annual Meeting and with EarthScope for the development of their Education and Outreach Program Plan. Future education programs and tools developed through COMPRES partnerships will place an increased emphasis on deep Earth materials and phenomena.

Richard, G. A.

2003-12-01

115

Numerical models of caldera-scale volcanic eruptions on Earth, venus, and Mars.  

UK PubMed Central (United Kingdom)

Volcanic eruptions of gassy magmas on Earth, Venus, and Mars produce plumes with markedly different fluid dynamics regimes. In large part the differences are caused by the differing atmospheric pressures and ratios of volcanic vent pressure to atmospheric pressure. For each of these planets, numerical simulations of an eruption of magma containing 4 weight percent gas were run on a workstation. On Venus the simulated eruption of a pressure-balanced plume formed a dense fountain over the vent and continuous pyroclastic flows. On Earth and Mars, simulated pressure-balanced plumes produced ash columns, ash falls, and possible small pyroclastic flows. An overpressured plume, illustrated for Mars, exhibited a complex supersonic velocity structure and internal shocks.

Kieffer SW

1995-09-01

116

Pr4B10O21: A new composition of rare-earth borates by high-pressure/high-temperature synthesis  

International Nuclear Information System (INIS)

[en] High-pressure chemistry led to the synthesis of the rare-earth borate Pr4B10O21 using a Walker-type multianvil apparatus at 3.5 GPa and 1050 deg. C. The tetra-praseodymium(III)-decaborate crystallizes monoclinicly with four formula units in the space group P21/n and lattice parameters of a=710.2(2), b=1948.8(4), c=951.6(2) pm, and ?=93.27(3)o. The boron-oxygen network consists of [BO4]5- tetrahedra and [BO3]3- groups; however, the [BO4]5- groups represent the major part (80%) due to the high-pressure conditions during the synthesis. The praseodymium ions are coordinated by 10 and 12 oxygen atoms. Along with a detailed description of the crystal structure, temperature programmed X-ray powder diffraction data are shown, demonstrating the metastable character of this compound. - Graphical abstract: Synthesis of Pr4B10O21 via the multianvil high-pressure/high-temperature technique representing a new composition of rare-earth borates

2007-01-01

117

High-pressure synthesis of rare-earth metal disulfides and diselenides LnX2 (Ln = Sm, Gd, Tb, Dy, Ho, Er and Tm; X = S, Se)  

International Nuclear Information System (INIS)

A series of rare-earth metal disulfides LnS2 and diselenides LnSe2 (Ln = Sm, Gd, Tb, Dy, Ho, Er and Tm) has been prepared by high-pressure high-temperature synthesis at 8(1) GPa. The dichalcogenides LnX2 (X = S, Se) are found to crystallize in the ?-LaS2 type with the monoclinic space group P121/a1 (no. 14). The crystal structure is a twofold superstructure of the ZrSSi aristotype and consists of puckered cationic [LnX]+ double slabs which are sandwiched by planar chalcogen sheets containing X22- dumbbells. (orig.)

2011-01-01

118

Effect of Horizontal Drain Length and Cutoff Wall on Seepage and Uplift Pressure in Heterogeneous Earth Dam with Numerical Simulation  

Directory of Open Access Journals (Sweden)

Full Text Available Design of earth dams and their problems are important during construction and after it,because of their potential hazards and failure for downstream population. This study focus on theeffectiveness of using horizontal drain and cutoff wall in reducing seepage flow from an assumedheterogeneous earth dam. For this purpose various horizontal drain lengths and cutoff wall depth examineunder the earth dam in different location of foundation. Seepage analysis, hydraulic gradient and upliftpressure, are computing by numerical simulation, using Seep/w software. Results show that increasinghorizontal drain length, cause slightly in increasing seepage rate and increasing hydraulic gradient.Optimum location of cut off wall for reduction of seepage rate and piping is in the middle of damfoundation. By increasing in cut off wall depth, seepage from earth dam and its foundation is reducing.Different location of cut off wall in dam foundation has little effect on exit hydraulic gradient and always itis less than unity. Installation of cut off wall in middle of foundation, results 19.68 percent decreasing inhydraulic gradient respect to existent of cut off wall in upstream of dam.

Behnam Mansuri; Farzin Salmasi

2013-01-01

119

INFLUENCE OF THE SHIFT OF CENTER OF PRESSURE OF THE HUMAN BODY ON THE OCCLUSAL BALANCE DENTITION  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of the study was to evaluate the correlation between the changes of central body pressure, influencing the spreadness of dental occlusion forces. Ten MSMSU students were included in the study (years 20-27), they showed no dental, vestibular or muscular-skeletal health problems. Experimental leg length discrepancies were provided by using ten types of insoles with heights ranging from one to ten mm at one mm intervals, placed under the whole feet surface of the right leg, than the same changes were made for the left one. The every following change was registered using TScan and MatScan systems. Based on the received data we can make the following conclusions: the right leg length growth results in the shift of central body pressure to the right, initial occlusion contact and center of occlusion force also shifts to the right; the left leg length growth results in the shift of central body pressure to the, initial occlusion contact and center of occlusion force also shifts to the left.

Peregudov Aleksey Borisovich; Savelev Vasiliy Vladimirovich; Ozhigov Evgeniy Mikhaylovich

2012-01-01

120

Relation of plasma noradrenaline to blood pressure, age, sex and sodium balance in patients with stable essential hypertension and in normotensive subjects.  

UK PubMed Central (United Kingdom)

1. Plasma noradrenaline was measured in 125 patients with stable essential hypertension (WHO I-II) and in 107 normotensive control subjects lying and standing. 2. In normotensive subjects and in patients with essential hypertension no sex-related differences of plasma noradrenaline were found between age-matched groups. 3. Plasma noradrenaline was not related to sodium balance indexed by urinary sodium/creatinine ratio. 4. In patients with essential hypertension plasma noradrenaline increases with age. 5. Mean plasma noradrenaline concentrations are significantly higher in patients with essential hypertension compared with age-matched normotensive subjects both lying and standing. 6. In patients with essential hypertension diastolic blood pressure and heart rate correlated significantly with supine plasma noradrenaline concentrations.

Brecht HM; Schoeppe W

1978-12-01

 
 
 
 
121

[Caught between Economic Pressure and Work-Life Balance - Perspectives on Emigration of German Health Professionals to Austria.  

UK PubMed Central (United Kingdom)

Given the increasing lack of medical doctors in Germany, this study aimed to investigate the professional situation and the push and pull factors of German medical specialists working in Austrian hospitals.This explorative study is based on semi-structured interviews with 14 specialists working in Austria, who completed their education partly or fully in Germany. The material has been interpreted using qualitative content analysis.Better work-life balance, higher quality of life and more favourable working conditions represent major reasons for German specialists to stay in Austria. Moreover, the higher density of medical doctors in Austrian hospitals can have an impact on the distribution of responsibilities among health-care personnel, and on hospital performance.In the light of recent reforms in the German health-care system, the study underlines the importance of qualitative factors for the satisfaction of German medical doctors. These factors should be further analysed in order to avoid a brain drain of high-qualified health care staff in the future.

Schmidt AE; Klambauer E

2013-06-01

122

[Caught between Economic Pressure and Work-Life Balance - Perspectives on Emigration of German Health Professionals to Austria.  

Science.gov (United States)

Given the increasing lack of medical doctors in Germany, this study aimed to investigate the professional situation and the push and pull factors of German medical specialists working in Austrian hospitals.This explorative study is based on semi-structured interviews with 14 specialists working in Austria, who completed their education partly or fully in Germany. The material has been interpreted using qualitative content analysis.Better work-life balance, higher quality of life and more favourable working conditions represent major reasons for German specialists to stay in Austria. Moreover, the higher density of medical doctors in Austrian hospitals can have an impact on the distribution of responsibilities among health-care personnel, and on hospital performance.In the light of recent reforms in the German health-care system, the study underlines the importance of qualitative factors for the satisfaction of German medical doctors. These factors should be further analysed in order to avoid a brain drain of high-qualified health care staff in the future. PMID:23780862

Schmidt, A E; Klambauer, E

2013-06-18

123

The PSI-O subunit of plant photosystem I is involved in balancing the excitation pressure between the two photosystems.  

UK PubMed Central (United Kingdom)

PSI-O is a subunit of photosystem I in eukaryotes. The function of PSI-O was characterized in Arabidopsis plants using RNA interference. Several transformants with the psaO-RNAi construct were generated, and a high proportion of the plants contained only very little or virtually no residual PSI-O. Plants lacking PSI-O have a 50% reduction in state transitions indicating a role for PSI-O in the balancing of excitation energy between the two photosystems. PSI-H and -L have been shown previously to be involved in state transitions, and immunoblot analysis revealed that plants devoid of PSI-L or -H also have 80-90% reduction in the abundance of PSI-O. In contrast, down-regulation of PSI-O has no negative effect on the content of PSI-H and -L. The interaction between PSI-O and the PSI-L was confirmed by chemical cross-linking. A model of PSI is proposed in which PSI-L as the most ancient subunit is closest to the reaction center, and PSI-O is positioned close to PSI-L on the PSI-H/-L/-I side of the PSI complex. PSI-H, -L, -O, and possibly -I are all involved in forming a domain in PSI that is involved in the interaction with light-harvesting complex II.

Jensen PE; Haldrup A; Zhang S; Scheller HV

2004-06-01

124

The PSI-O subunit of plant photosystem I is involved in balancing the excitation pressure between the two photosystems.  

Science.gov (United States)

PSI-O is a subunit of photosystem I in eukaryotes. The function of PSI-O was characterized in Arabidopsis plants using RNA interference. Several transformants with the psaO-RNAi construct were generated, and a high proportion of the plants contained only very little or virtually no residual PSI-O. Plants lacking PSI-O have a 50% reduction in state transitions indicating a role for PSI-O in the balancing of excitation energy between the two photosystems. PSI-H and -L have been shown previously to be involved in state transitions, and immunoblot analysis revealed that plants devoid of PSI-L or -H also have 80-90% reduction in the abundance of PSI-O. In contrast, down-regulation of PSI-O has no negative effect on the content of PSI-H and -L. The interaction between PSI-O and the PSI-L was confirmed by chemical cross-linking. A model of PSI is proposed in which PSI-L as the most ancient subunit is closest to the reaction center, and PSI-O is positioned close to PSI-L on the PSI-H/-L/-I side of the PSI complex. PSI-H, -L, -O, and possibly -I are all involved in forming a domain in PSI that is involved in the interaction with light-harvesting complex II. PMID:15169790

Jensen, Poul Erik; Haldrup, Anna; Zhang, Suping; Scheller, Henrik Vibe

2004-03-30

125

Pressurizer  

International Nuclear Information System (INIS)

[en] A thin walled tube is welded on to the coupling of the overpressure protection in the lid of the pressurizer. The tube opening is located above the highest possible water level in the pressurizer occurring at different regimes of the nuclear power plant. The advantage of the configuration is that an elastic steam cushion is always preserved in the pressurizer during an accident. (Ha)

1980-01-14

126

Responses of Earth's radiation belts to solar wind dynamic pressure variations in 2002 analyzed using multisatellite data and Kalman filtering  

Science.gov (United States)

It has been difficult to establish a definitive causal link between radiation belt electron dropouts and solar wind dynamic pressure, due to adiabatic effects and observations limited to a single location in space at one time. Here we reconstruct the radial profiles of radiation belt electron phase space density (PSD) for the entire year of 2002 (solar maximum), based on a combination of the VERB radial diffusion model and data assimilation of the sparse observations from six satellites including GEO1989, GEO1990, LANL-97A, LANL-01A, GPSns33, and POLAR, to perform a statistical analysis of the potential relationship between electron PSD dropout and solar wind dynamic pressure variation. We capture 59 electron PSD dropout events, 81% associated with solar wind dynamic pressure sudden jumps (i.e., pulses) or modest increase, consistent with the results of Shprits et al. (2012) for the period of 1990-1991. With the continuous availability of high quality solar wind data in 2002, we further identify 41 pressure pulses and determine that 68% of them are associated with electron PSD dropouts. We also identify 49 pressure enhancements, 41% of which are associated with electron PSD dropouts. Our results support that gradual or sharp enhancements in solar wind dynamic pressure can play an important role in producing electron PSD dropouts, owing to inward intrusion of the magnetopause that enhances the loss to the magnetopause and outward radial diffusion. But we conclusively demonstrate that solar wind dynamic pressure pulses and enhancements are neither a necessary nor a sufficient condition for the formation of electron PSD dropouts, which suggests that some other mechanism(s), which remains mysterious, is required to explain electron PSD dropout occurrences without pressure pulse or modest pressure increase. For the first time, we also perform a quantitative comparison of conjunctions between electron PSD reanalysis results and satellite PSD data, which indicates a tolerable and reasonable error in assimilated PSD within a factor of 5. Differences in assimilated PSD and satellite PSD have a potential for use to evaluate the ignored processes in the physical model and to estimate the errors associated with satellite measurements.

Ni, Binbin; Shprits, Yuri Y.; Friedel, Reiner H. W.; Thorne, Richard M.; Daae, Marianne; Chen, Yue

2013-07-01

127

Fault-related-folding structure and reflection seismic sections. Construction of earth model using balanced cross section; Danso ga kaizaisuru shukyoku kozo no keitai to jishin tansa danmen. 1. Balanced cross section wo mochiita chika model no kochiku  

Energy Technology Data Exchange (ETDEWEB)

Pre-stacking depth migration treatment is studied for the estimation of the fold configuration from seismic survey cross sections. The estimation of a velocity structure is necessary for the execution of such treatment, and the utilization of structural-geological knowledge is required for its interpretation. The concept of balanced cross section in relation to the fault-bend fold constructs a stratum structure model under conditions that the deformation during fold and fault formation is a planar strain, that there is no change in volume due to deformation, and that a fold is a parallel fold. In addition to the above geometric and kinetic approach, there is another fold formation process simulation model using a Newtonian fluid for study from the viewpoint of dynamics. This simulation stands on the presumption that the boundary contains a ramp that had been in presence before fold formation and that an incompressible viscous matter is mounted on the top surface. The viscous matter flows and deforms for the formation of an anticline on the ramp. Such enables the reproduction of a fault-bend fold formation process, and helpful discussion may be furthered on the dynamic aspect of this simulation. 5 refs., 4 figs.

Matsuoka, T.; Tamagawa, T. [Japan Petroleum Exploration Corp., Tokyo (Japan); Tsukui, R. [Japan National Oil Corp., Tokyo (Japan). Technology Research Center

1997-05-27

128

Some aspects of designing earth pressures for braced wall under the bottom of excavation; Kussaku teimenka ni okeru tsuchidome heki sayosuru sekkei doatsu no kangaekata  

Energy Technology Data Exchange (ETDEWEB)

As the designing methods which can express behavior on earth retaining wall faithfully, means of the elastic plasticity method, the finite elemental model (FEM), etc. have been proposed generally. But, regarding the elastic plasticity method, deformation of the retaining wall, axial force of the bridging, etc. have not always coincided with measured values. In the Osaka City Traffic Bureau, in case of shallow excavation which has no neighboring construction in the back, customary calculations which have had many actual results are used. But, in case that the depth of excavation comes up to 20-30m, the elastic plasticity method which has been suited with ground of Osaka area is applied, and in particular in case that behavior in the back of ground is important, the FEM is used as a complement. Principal lateral pressure for the upper part than excavating bottom is calculated by Rankine-Resal formula owing to possibility which may form some gap at the back of retaining wall. In case under the bottom of excavation, if the lower end of retaining wall is driven sufficiently into strong ground, calculation applying means that principal lateral pressure is to decrease corresponding to triangle distribution drawn by connecting lateral pressure at the bottom of excavation with the lower end of wall agree well with actual measured values. 8 refs., 8 figs.

Kishio, T.; Ota, H.; Hashimoto, T.; Konda, T.

1997-10-01

129

Structural, electronic, elastic and high-pressure properties of some alkaline-earth chalcogenides: An ab initio study  

International Nuclear Information System (INIS)

The full-potential linearized augmented plane wave method (FP-LAPW) within the generalized gradient approximation (GGA) is used to calculate the electronic band structures and the total energies of BaS, CaSe and CaTe in NaCl and CsCl-type structures. The latter provide us with the ground states properties such as lattice parameter, bulk modulus and its pressure derivative, elastic constants and the structural phase stability of these compounds. The transition pressures at which these compounds undergo the structural phase transition from NaCl to CsCl phase are calculated. The energy band gaps and their volume dependence in NaCl and CsCl type-structures are investigated. The pressure and the volume at which band overlap metallization occurs are also determined. The ground state properties, the transition and metallization pressures (volumes) are found to agree with the experimental and other theoretical results. The elastic constants at equilibrium in both NaCl and CsCl structures are calculated and compared with the available theoretical results for CaSe, while for BaS and CaTe the elastic constants are not available.

2006-01-15

130

Effect of pressure on the size of energy gap in semiconducting mixed-valent rare-earth compounds  

International Nuclear Information System (INIS)

We have synthesized CeRhBi and CeRhAs and found that these compounds crystallize in the ?-TiNiSi-type structure. It is found that CeRhBi is a heavy-fermion compound, whereas CeRhAs is a mixed-valent semiconductor with an energy gap of 144 K, about 10 times larger than that of CeRhSb. Various experimental results throughout the CeRhX series also vary in the sequence CeRh (Bi-Sb-As). However, the gap observed in CeRhAs is suppressed by external-pressure, suggesting that the chemical and the external pressure seem to cause opposite effects on the size of energy gap in these compounds. These results are compared with those for mixed-valent semiconductors Ce3Pt3Bi4 and Ce3Pt3Sb4. (orig.).

1996-01-01

131

Growth of Carnobacterium spp. from permafrost under low pressure, temperature, and anoxic atmosphere has implications for Earth microbes on Mars.  

UK PubMed Central (United Kingdom)

The ability of terrestrial microorganisms to grow in the near-surface environment of Mars is of importance to the search for life and protection of that planet from forward contamination by human and robotic exploration. Because most water on present-day Mars is frozen in the regolith, permafrosts are considered to be terrestrial analogs of the martian subsurface environment. Six bacterial isolates were obtained from a permafrost borehole in northeastern Siberia capable of growth under conditions of low temperature (0 °C), low pressure (7 mbar), and a CO(2)-enriched anoxic atmosphere. By 16S ribosomal DNA analysis, all six permafrost isolates were identified as species of the genus Carnobacterium, most closely related to C. inhibens (five isolates) and C. viridans (one isolate). Quantitative growth assays demonstrated that the six permafrost isolates, as well as nine type species of Carnobacterium (C. alterfunditum, C. divergens, C. funditum, C. gallinarum, C. inhibens, C. maltaromaticum, C. mobile, C. pleistocenium, and C. viridans) were all capable of growth under cold, low-pressure, anoxic conditions, thus extending the low-pressure extreme at which life can function.

Nicholson WL; Krivushin K; Gilichinsky D; Schuerger AC

2013-01-01

132

Growth of Carnobacterium spp. from permafrost under low pressure, temperature, and anoxic atmosphere has implications for Earth microbes on Mars.  

Science.gov (United States)

The ability of terrestrial microorganisms to grow in the near-surface environment of Mars is of importance to the search for life and protection of that planet from forward contamination by human and robotic exploration. Because most water on present-day Mars is frozen in the regolith, permafrosts are considered to be terrestrial analogs of the martian subsurface environment. Six bacterial isolates were obtained from a permafrost borehole in northeastern Siberia capable of growth under conditions of low temperature (0 °C), low pressure (7 mbar), and a CO(2)-enriched anoxic atmosphere. By 16S ribosomal DNA analysis, all six permafrost isolates were identified as species of the genus Carnobacterium, most closely related to C. inhibens (five isolates) and C. viridans (one isolate). Quantitative growth assays demonstrated that the six permafrost isolates, as well as nine type species of Carnobacterium (C. alterfunditum, C. divergens, C. funditum, C. gallinarum, C. inhibens, C. maltaromaticum, C. mobile, C. pleistocenium, and C. viridans) were all capable of growth under cold, low-pressure, anoxic conditions, thus extending the low-pressure extreme at which life can function. PMID:23267097

Nicholson, Wayne L; Krivushin, Kirill; Gilichinsky, David; Schuerger, Andrew C

2012-12-24

133

Experimental Study on the Performance of the Passive Safety Injection for Pressure Balance Line Break and Direct Vessel Injection Line Break  

International Nuclear Information System (INIS)

[en] A passive core cooling system (PCCS) has been installed at the Institute of Nuclear Energy Research (INER) Integral System Test (IIST) facility. It includes three core makeup tanks (CMTs), three accumulators (ACCs), a-four stage automatic depressurization system (ADS), a passive residual heat removal (PRHR) heat exchanger submerged into an in-containment refueling water storage tank (IRWST). The purpose of this research is to study the performance of the PCCS with passive injection during either a pressure balance line (PBL) break or a direct vessel injection (DVI) line break. Five experiments were performed simulating break area ratios of 0.5% to 2.0% (1.88 mm to 3.77 mm) at either a PBL or at a DVI-line. The general system response and the interactions of CMT, ACC, PRHR, and IRWST to the effect of core heat removal are observed and discussed. The experimental results show long term core cooling can be reached for the cases of the PBL break and the DVI-line break following the PCCS actuation procedures. (authors)

2002-01-01

134

Complex refractive indices of tholins produced from various initial gas mixtures and formation pressures: Implications for Titan, the early Earth, and the outer solar system bodies  

Science.gov (United States)

Organic materials may exist as haze layers in the atmospheres of Titan and the early Earth and as dark coloring agents on icy satellite surfaces. Khare et al. (1984) measured the complex refractive indices of Titan tholin produced from N2/CH4 (90/10) gas mixture, which has been used to model the optical properties of organic materials in the outer solar system. However, the optical properties of tholin may depend on experimental conditions. Therefore, determinations of the complex refractive indices of tholins at various experimental conditions are important. Figure shows the complex refractive indices (0.185 - 25 ?m) of Titan tholins generated by cold plasma in N2/CH4 (90/10) gas mixture at pressures of 0.26 hPa and 1.6 hPa. Optical properties strongly depend on formation pressures, and it firstly reveals several overtone bands in near-IR regions. These data are particularly useful in modeling of atmospheric radiative transfer and surface spectra of icy satellite surfaces.

Imanaka, H.; Khare, B. N.; McKay, C. P.; Cruikshank, D. P.

2005-08-01

135

Pressure  

Science.gov (United States)

This page contains three Physlets that are able to share data using a connection made by a common superclass, SApplet. The ensemble walls keep track of the change in momentum, i.e., the pressure, during each time step, dt, and provides this data to the DataGraph Physlet and the DataTable Physlet.

Christian, Wolfgang; Belloni, Mario

2008-02-09

136

Análise da pressão plantar e do equilíbrio postural em diferentes fases da gestação/ Analysis of plantar pressure and postural balance during different phases of pregnancy  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese OBJETIVO: Analisar a pressão plantar e o equilíbrio postural nos três trimestres de gravidez, bem como a correlação com as características antropométricas. METODOLOGIA: 60 voluntárias com idade média de 23,3 ± 5,5 anos, sendo 15 mulheres em cada grupo: não-gestantes (C), primeiro (1T), segundo (2T) e terceiro trimestre (3T). A avaliação foi efetuada por meio de plataforma de pressão na posição bipodal com os olhos abertos. As variáveis analisadas nos pés (more) direito e esquerdo foram: pico de pressão em todo o pé (PT), no antepé (PA) e no retropé (PR); distância entre a borda medial dos pés (largura da base de suporte); distância do centro de força ao limite anterior (CFF) e posterior (CFC) dos pés; deslocamento ântero-posterior (AP) e médio--lateral (ML) do centro de força; e área de contato (AC). RESULTADOS: Não houve diferença no pico de pressão de contato e na distância CFF e CFC entre os grupos. O deslocamento AP foi maior (p 0,05) entre os grupos para o deslocamento ML. Houve correlação positiva entre peso ganho durante a gestação com AC para o grupo 2T e com PT no pé direito do grupo 1T. CONCLUSÃO: Os resultados demonstram a influência das mudanças anatômicas e fisiológicas inerentes à gestação na pressão plantar, além de sugerir uma redução do equilíbrio postural no 3T, relacionada ao maior deslocamento AP nessa fase. Abstract in english OBJECTIVE: To analyze plantar pressure and postural balance during the three trimesters of pregnancy, and also to correlate these with anthropometric characteristics. METHOD: Sixty volunteers participated in this study, with a mean age of 23.3 ± 5.5 years. There were 15 subjects in each group: non-pregnant (C), first trimester (1T), second trimester (2T) and third trimester (3T). Evaluations were performed in bipedal stance with open eyes, using a pressure platform. The (more) following variables were analyzed in the right and left feet: peak pressures in the whole foot (WFP), forefoot (FFP) and hindfoot (HFP); distance between the medial borders of the foot (width of support base); the distance from the center of force to the anterior (COF-A) and posterior (COF-P) limits of the foot; anteroposterior (AP) and mediolateral (ML) COF displacements; and the contact area (CA). RESULTS: There were no differences in peak contact pressures and COF-A and COF-P distances between the groups. The AP displacement was greater (p 0.05) between the groups regarding ML displacement. There was a positive correlation between weight gained during pregnancy and CA for the 2T group, and between weight gain and WFP in the right feet in the 1T group. CONCLUSION: The results demonstrate the influence of the anatomical and physiological changes inherent to pregnancy on plantar pressure. They also suggest that postural equilibrium decreases in the third trimester, associated with greater AP displacement during this phase.

Ribas, SI; Guirro, ECO

2007-10-01

137

Solubility of Uranium in Fe-S-Si Melts at High Pressure and Temperature and at Highly Reducing Conditions: Uranium as a heat source in the Earth's Core?  

Science.gov (United States)

The presence of Uranium and its role as a radioactive heat source in the Earth's Fe-metallic core has been controversial (e.g., Wheeler et al., 2006; Bao et al., 2005). We report here on partitioning of U between molten enstatite chondrite and Fe-S-Si melts at about 4 log units below the Iron-Wustite oxygen buffer and pressures between 3 and 8 GPa. All experiments were performed at super-liquidus temperatures in the range of 2000- 2400 C. Both the metal and silicates were completely molten, in keeping with the concept of an early global magma ocean. At these pressures and temperatures, the partition coefficient, DU (U concentration in metallic sulfide liquid/U concentration in molten silicate) is in the range of 0.03-0.08. DU is positively correlated with S as observed in prior studies (Bao et al., 2005; Wheeler et al., 2006), but is inversely correlated with Si in metallic liquid. In metal with little or no sulfur, DU is lower by an order of magnitude or more. In the range of our measurements, no strong effect of either T or P on the partition coefficient is observed. U shows no correlation with Ca suggesting that U is not carried via CaS at these highly reducing conditions, as has been suggested (Murrell and Burnett, 1982; Furst et al., 1982). Nor does the U content of metal-sulfide have any discernible dependency on the O content of the metallic liquid. Thus it appears that neither Ca nor O act as carriers or catalytic agents for the entry of U into Fe-S melts. Rather, we suggest that the reaction UO2 +2 FeS = US2 +2FeO proceeds to the right at elevated P and T and highly reducing conditions, facilitating the incorporation of U in Fe-S liquids. Assuming that the behavior of DU is not significantly changed at the much higher P and T relevant to the magma ocean, our data permit 0.6-1.8 ppb of U in the core with heat production capacity of 0.1-0.3 TW at present, a small fraction of the 6-12 TW total heat flux from the core (Buffet, 2003). We conclude that under highly reducing conditions uranium might be incorporated into the Earth's metallic core.

Murthy, V.; Draper, D. S.; Agee, C. B.

2006-12-01

138

Effect of Intermittent Positive Pressure Ventilation (IPPV) on Acid-Base Balance and Plasma Electrolytes during Isoflurane Anaesthesia in Sulphur-Crested Cockatoos (Cacatua galerita galerita)  

Directory of Open Access Journals (Sweden)

Full Text Available The objective of the study was to investigate the effect of Intermittent Positive Pressure Ventilation (IPPV) on acid-base balance and plasma electrolytes during isoflurane anaesthesia in sulphur-crested cockatoos (Cacatua galerita galerita) Anaesthesia was induced in six birds by mask using a T-piece with 3.0% isoflurane. Blood gases, plasma electrolytes, PCV and Total Protein (TP) were monitored for one hour during Spontaneous Ventilation (SV) and IPPV. IPPV was instituted by engaging the pop-off valve (IPPVa) of the circle absorber or by squeezing the breathing bag (IPPVb). Results showed that during SV, pCO2, pO2, [HCO3-], BE, C+CO2 and PO4- increased significantly, while [Na+], [K+] and [Ca2+] did not change significantlyDuring IPPV, pCO2 and pO2 decreased, while C+CO2 CO2 increased during the initial 30 min. [HCO3-increased during IPPVa only in the first 30 min. BE increased only in the first 30 min of IPPV. There was a marginal increase and decrease in PO4- during SV and IPPV, respectively. [Na+], [K+] and [Ca2+] remained stable during both SV and IPPV. Subtle decreases were noted for [Cl-] TP and PCV during SV. It was concluded that mixed metabolic and respiratory acidosis occurs during SV in isoflurane-anaesthetised cockatoos. Metabolic acidosis that develops during isoflurane anaesthesia in spontaneously ventilating birds is reversible to some extent by IPPV, possibly through a mixed acidosis-alkalosis, respiratory alkalosis and a non-respiratory contribution to alkalosis mechanism. Reversal of Bohr Effect occurs during IPPV in isoflurane-anaesthetised cockatoos. Studies are indicated to understand the causes of decreased oxygen saturation in apparently alkalotic birds.

Saul Chemonges

2012-01-01

139

Back analysis by EK-filter for coefficient of subgrade reaction and earth pressure in excavation work; Kakucho Kalman filter ni yoru jiban hanryoku keisu yamadome sayo sokuatsu no doji suitei  

Energy Technology Data Exchange (ETDEWEB)

Construction under server conditions such as large earth retaining excavation on the soft ground or in cities has been increasing recently. A computerized system that performs construction works while grasping the safety of an earth retaining structure or the effect on adjacent structures has also been increasing. In this system, the back analysis plays an important part. However, there are many problems to be examined such as matching with a measurement value, convergence characteristics of a solution, and estimated precision when measurement data is used. In this paper, a back analysis method was proposed to improve the fitting to an observation value and convergence characteristics when the coefficient of subgrade reaction and the earth pressure are estimated simultaneously. In this method, the moment obtained by differentiating the tilt angle of an earth retaining wall is treated as an observation value, and the side pressure as observation and state values. The way to easily evaluate the ground behavior during measurement by the estimation result was also proposed. It is used to evaluate the ground behavior in the earth retaining excavation stage from the simple measurement data for the tilt angle on a wall and the axial force of a strut. 19 refs., 9 figs., 6 tabs.

Kobayashi, N.; Saito, E. [Fujita Corp., Tokyo (Japan)

1997-03-21

140

Phase Transitions and Equations of State of Alkaline Earth Fluorides CaF2 SrF2 and BaF2 to Mbar Pressures  

Energy Technology Data Exchange (ETDEWEB)

Phase transitions and equations of state of the alkaline earth fluorides CaF{sub 2}, SrF{sub 2}, and BaF{sub 2} were examined by static compression to pressures as high as 146 GPa. Angle-dispersive x-ray diffraction experiments were performed on polycrystalline samples in the laser-heated diamond-anvil cell. We confirmed that at pressures less than 10 GPa all three materials undergo a phase transition from the cubic (Fm3{sup -}m) fluorite structure to the orthorhombic (Pnam) cotunnite-type structure. This work has characterized an additional phase transition in CaF{sub 2} and SrF{sub 2}: these materials were observed to transform to a hexagonal (P6{sub 3}/mmc) Ni{sub 2}In-type structure between 63-79 GPa and 28-29 GPa, respectively, upon laser heating. For SrF{sub 2}, the Ni{sub 2}In-type phase was confirmed by Rietveld refinement. Volumes were determined as a function of pressure for all high-pressure phases and fit to the third-order Birch-Murnaghan equation of state. For CaF{sub 2} and SrF{sub 2}, the fluorite-cotunnite transition results in a volume decrease of 8-10%, while the bulk modulus of the cotunnite-type phase is the same or less than that of the fluorite phase within uncertainty. For all three fluorides, the volume reduction associated with the further transition to the Ni{sub 2}In-type phase is {approx}5%. The percentage increase in the bulk modulus ({Delta}K) across the transition is greater when the cation is smaller. While for BaF{sub 2}, {Delta}K is 10-30%, {Delta}K values for SrF{sub 2} and CaF{sub 2} are 45-65% and 20-40%. Although shock data for CaF{sub 2} have been interpreted to show a transition to a highly incompressible phase above 100 GPa, this is not consistent with our static equation of state data.

S Dorfman; F Jiang; Z Mao; A Kubo; Y Meng; V Prakapenda; T Duffy

2011-12-31

 
 
 
 
141

Phase Transitions and Equations of State of Alkaline Earth Fluorides CaF2 SrF2 and BaF2 to Mbar Pressures  

International Nuclear Information System (INIS)

Phase transitions and equations of state of the alkaline earth fluorides CaF2, SrF2, and BaF2 were examined by static compression to pressures as high as 146 GPa. Angle-dispersive x-ray diffraction experiments were performed on polycrystalline samples in the laser-heated diamond-anvil cell. We confirmed that at pressures less than 10 GPa all three materials undergo a phase transition from the cubic (Fm3-m) fluorite structure to the orthorhombic (Pnam) cotunnite-type structure. This work has characterized an additional phase transition in CaF2 and SrF2: these materials were observed to transform to a hexagonal (P63/mmc) Ni2In-type structure between 63-79 GPa and 28-29 GPa, respectively, upon laser heating. For SrF2, the Ni2In-type phase was confirmed by Rietveld refinement. Volumes were determined as a function of pressure for all high-pressure phases and fit to the third-order Birch-Murnaghan equation of state. For CaF2 and SrF2, the fluorite-cotunnite transition results in a volume decrease of 8-10%, while the bulk modulus of the cotunnite-type phase is the same or less than that of the fluorite phase within uncertainty. For all three fluorides, the volume reduction associated with the further transition to the Ni2In-type phase is ?5%. The percentage increase in the bulk modulus (?K) across the transition is greater when the cation is smaller. While for BaF2, ?K is 10-30%, ?K values for SrF2 and CaF2 are 45-65% and 20-40%. Although shock data for CaF2 have been interpreted to show a transition to a highly incompressible phase above 100 GPa, this is not consistent with our static equation of state data.

2010-05-01

142

Finite element analysis on interaction between earth pressure against reinforced retaining walls and tensile force of reinforcements; Hokyodo yoheki no hekimen doatsu to hokyozai choryoku no sogo kankei ni kansuru yugen yoso kaiseki  

Energy Technology Data Exchange (ETDEWEB)

Study was made on the relation between earth pressure against walls and tensile force of reinforcements considering the strain level of back-fill soil of reinforced retaining walls. By use of a reinforced retaining wall for centrifugal model experiment as analytical model, wall displacement, tensile force of reinforcements, earth pressure on walls, and the relation of frictional force between reinforcement and soil were studied by FEM analysis. As a result, the wall face displacement increased with pressure, and showed a peak at the center of a wall. The tensile force of reinforcements was larger than earth pressure against walls under a stable condition, and this difference was probably derived from frictional force on reinforcement surfaces. The former was close to the latter under a fractured condition showing smaller frictional forces. This was also confirmed by centrifugal model experiment. The wall displacement was stable due to an expected increase in frictional force of reinforcements in the early stage, however, it became unstable with a decrease in frictional force at an approach of fracture. 22 refs., 19 figs., 1 tab.

Kawamura, M. [Toyohashi University of Technology, Aichi (Japan); Okabayashi, K. [Kochi National College of Technology, Kochi (Japan)

1998-06-21

143

Centrifugal model test on interaction between earth pressure against reinforced retaining walls and tensile force of reinforcements; Hokyodo yoheki no hekimen doatsu to hokyozai choryoku no sogo kankei ni kansuru enshinryoku mokei jikken  

Energy Technology Data Exchange (ETDEWEB)

When considering on the evaluation of stability, especially inner stability problem of the reinforced retaining wall, in order to obtain a rational solution, it is necessary to elucidate the interaction among deformation of the reinforced retaining wall, especially displacement of wall face and tension of reinforcements, each pressure acting to wall face, and frictional force between reinforcements and soils. In this study, aiming to clear interacting relationships among displacement for wall, tension of reinforcements, earth pressure for wall, and ground displacement in such reinforced retaining wall, a centrifugal loading model test was conducted to measure actually these relationships in cases of during stability and destruction. As a result, it was found that during stability where backfill soils were nondestructive state, earth pressure for wall and tension of reinforcements became smaller than their design values, and displacement for wall increased and when backfill ground became plastic state, they agreed well with present design values. That is to say, a relationship between earth pressure for wall as a function of deformation of reinforced retaining wall and tension of reinforcements was elucidated. 19 refs., 18 figs., 2 tabs.

Kawamura, M. [Toyohashi Univ., of Technology, Aichi (Japan). Faculty of Engineering; Okabayashi, K. [Kochi National College of Technology, Kochi (Japan)

1998-03-21

144

Rare earth gas laser  

Science.gov (United States)

A high energy gas laser with light output in the infrared or visible region of the spectrum is described. Laser action is obtained by generating vapors of rare earth halides, particularly neodymium iodide or, to a lesser extent, neodymium bromide, and disposing the rare earth vapor medium in a resonant cavity at elevated temperatures; e.g., approximately 1200/sup 0/ to 1400/sup 0/K. A particularly preferred gaseous medium is one involving a complex of aluminum chloride and neodymium chloride, which exhibits tremendously enhanced vapor pressure compared to the rare earth halides per se, and provides comparable increases in stored energy densities.

Krupke, W.F.

1975-10-31

145

Uniqueness of Herndon's Georeactor: Energy Source and Production Mechanism for Earth's Magnetic Field  

CERN Multimedia

Herndon's georeactor at the center of Earth is immune to meltdown, which is not the case for recently published copy-cat georeactors, which would necessarily be subject to hot nuclear fuel, prevailing high temperature environments, and high confining pressures. Herndon's georeactor uniquely is expected to be self-regulating through establishing a balance between heat production and actinide settling out. The seven decade old idea of convection in the Earth's fluid core is refuted because thermal expansion cannot overcome the 23 percent higher density at the core's bottom than at its top. Some implications of geomagnetic field production within Herndon's georeactor are briefly described.

Herndon, J Marvin

2009-01-01

146

Separation of the rare earths by high pressure liquid chromatography and the fission yield on sup(148m)Pm and sup(148g)Pm using thermal neutron induced fission of 233U and 239Pu  

International Nuclear Information System (INIS)

[en] This report is in two parts: in the first part, the method of high pressure liquid chromatography is described with particular reference to rare earth nuclei produced in nuclear reactions; in the second part, the results of a study of the fission yield of sup(148m)Pm and sup(148g)Pm from the thermal fission of 233U and 239Pu are presented. (G.T.H.)

1979-01-01

147

Earth's Elastic Response to Seasonal Cycles in Surface Loading in Greenland and Antarctica  

Science.gov (United States)

Newly installed polar geodetic networks such as the Greenland GPS Network (GNET) and the Antarctic GPS Network (ANET) provide a means to determine the movement of the Earth’s crust in response to past and present changes in ice mass. It is possible to distinguish between bedrock motions driven by glacial isostatic adjustment (GIA) - the response of the crust and mantle to past changes in ice mass, and those caused by the contemporary steady or time-linear component of the Earth’s instantaneous elastic response to present day changes in ice mass, by focusing on accelerations in secular rebound rates, which can only be due to accelerating trends in modern ice mass change. Seasonal cycles in crustal motion, which manifest Earth’s purely elastic response to cycles in surface loads, are completely distinguishable from GIA. However, we shall show that in many cases the seasonal displacement cycles recorded by GPS stations in Greenland and Antarctica manifest Earth’s elastic response to seasonal variations in atmospheric pressure as well as seasonal cycles in ice mass. Fortunately the atmospheric pressure cycles can be modeled quite well using data from existing meteorology stations, allowing the ice mass signal to be isolated - especially in the case of Greenland. In most situations when the pressure signal is removed, the seasonal elastic signal can be accounted for by seasonal variations in ice surface mass balance. Where this is not the case, it seems likely that variations in local ice dynamics that cause changes in local loads will be manifest. In addition to the investigation of the interplay between the cryosphere and the solid Earth the new polar geodetic networks are used for water vapor meteorology studies, analysis of ionospheric phenomena and space weather, and enhanced navigational support for airborne LIDAR surveys.

Kendrick, E. C.; Bevis, M. G.; Brown, A. K.; Madsen, F.; Khan, S. A.; Willis, M. J.; Vandam, T.; Forsberg, R.; Box, J. E.; Wilson, T. J.; Caccamise, D., II; Konfal, S. A.; Johns, B.

2010-12-01

148

Google Earth  

Science.gov (United States)

Google Earth has gone underwater with this latest iteration of their popular Earth-roaming application. Along with traveling the usual roads provided by previous versions of Google Earth, visitors can now visit the bottom of the Mariana Trench, learn about ocean observations, and even discover new places to surf and dive. On the Google Earth homepage, visitors can take a guided tour of all these new features. This version is compatible with all operating systems.

2009-01-01

149

Balancing Work and Family: A Panel Analysis of the Impact of Part-Time Work on the Experience of Time Pressure  

Science.gov (United States)

In this article we consider the consequences of work-family reconciliation, in terms of the extent to which the adjustment of the labour market career to family demands (by women) contributes to a better work-life balance. Using the Flemish SONAR-data, we analyse how changes in work and family conditions between the age of 26 and 29 are related to…

Laurijssen, Ilse; Glorieux, Ignace

2013-01-01

150

The effect of different skin-ankle brace application pressures with and without shoes on single-limb balance, electromyographic activation onset and peroneal reaction time of lower limb muscles.  

UK PubMed Central (United Kingdom)

BACKGROUND: Several studies have been carried out in order to investigate the effect of ankle bracing on ankle joint function and performance. However, no study so far has examined the role of skin-brace interface pressure in neuromuscular control. The aim of this study was to investigate the effect of different skin-ankle brace interface pressures, with and without shoes, on quiet single-limb balance and the electromyographic (EMG) activation sequence of four lower limb muscles. METHODS: Twelve male physical education students who volunteered to take part in the study were measured with and without shoes under three ankle brace conditions: (i) without brace, (ii) with brace and 30 kilopascals (kPa) application pressure and (iii) with brace and 60 kPa application pressure. Single-limb balance (anteroposterior and mediolateral parameter) was assessed on the dominant lower limb, with open and closed eyes, on a force platform, simultaneously with the EMG recording of four lower lower limb muscles' (gastrocnemius, peroneus longus, rectus femoris and biceps femoris) activation onset. Peroneus longus reaction time was also measured by provoking a sudden subtalar inversion stress test using a trap-door. RESULTS: The results showed that the application of athletic footwear resulted in a significant difference between the condition with shoes and without shoes, with a significantly increased anteroposterior sway and sway velocity, in all three ankle brace application conditions with shoes (F=50.9, d.f.=1, p<0.001 and F=58.4, d.f.=1, p<0.001), but had no effect in the mediolateral stability, or the total stability parameter. Shoes had no significant effect on the EMG activation sequence of the four lower limb muscles. Lastly, ankle brace application with 30 and 60 kPa application pressures, with and without athletic footwear, led to a significant delay in the peroneus longus reaction time (F=9.71, d.f.=2, p<0.001). CONCLUSIONS: These findings suggest that different ankle brace application pressures may have an effect on single-limb balance, and peroneal reaction time. The application of athletic footwear, further adversely affects these parameters significantly. Further research is needed in this area with more dynamic and functional measurements, before the safe use of ankle bracing can be widely recommended.

Papadopoulos ES; Nikolopoulos CS; Athanasopoulos S

2008-12-01

151

Mars, earth, and ice  

Energy Technology Data Exchange (ETDEWEB)

Possible mechanisms to explain the global ice covering of Mars, and previous ice ages on the earth, are considered. Evidence for the Milankovitch effect is found in the close correspondence of earth's past climate with its orbital variations, as recorded principally in ocean sediments, and the role of CO/sub 2/ is discussed. Mars' range of obliquity, 10 times that of the earth, and orbital eccentricity, fluctuating over a range 2 1/2 times that of the earth, could produce an important climate-driving cycle. Mathematical models of the Martian surface and atmosphere based on Viking data suggest that escaped CO/sub 2/ could create a surface pressure of 1-3 bars. Other factors such as the effect of continental drift, the increased brightness of the sun, and planetary reversals of magnetic field polarity are discussed, and the questions of where Martian water and CO/sub 2/ have gone are considered.

Cordell, B.M.

1986-07-01

152

Formulation of high-precision volume-of-fluid method establishing appropriate balance between pressure and surface tension and its application to gas entrainment phenomena in fast breeder reactors  

International Nuclear Information System (INIS)

To evaluate directly gas entrainment (GE) phenomena in fast reactors, a numerical simulation method based on a high-precision volume-of-fluid (VOF) methodology have been studied. Unstructured meshes to subdivide simulation domains have been employed because exact modeling of complicated geometries is necessary for GE simulations. In this note, formulations of each calculation procedure in the high-precision VOF methodology on unstructured meshes are briefly presented. Calculation procedures of surface tension forces are also presented. In addition, unphysical behaviors of velocity distributions near gas-liquid interface induced by inappropriate formulation of pressure gradient are addressed and an appropriate formulation is presented considering proper balance conditions between pressure and surface tension forces. Finally, the improved simulation method is applied to the basic GE experiment. The simulation results show that the GE phenomena occur in the same mechanism with the experimental results. (author)

2009-01-01

153

A two-stage scenario for the formation of the Earth's mantle and core  

Science.gov (United States)

Various geophysical constraints on the deep Earth point to a chemically heterogeneous mantle. Based on such constraints, Bulk Earth compositions inferred from Enstatite chondrites (E-Earth composition) predict that, whereas the Primitive Upper mantle (PUM) had a pyrolitic composition, the Primitive Lower mantle (PLoM) was enriched in Fe and Si. In E-Earth formalism, this chemical heterogeneity is related to the formation and differentiation of the Early Earth, and mantle Si and Fe variations reflect variations in the efficiency of Si and FeO dissolution in the metal phase during core formation. In the simplest scenario of homogeneous accretion, we calculate by mass balance the composition and the mass fraction of the metallic extract in equilibrium with a pyrolite. The O, Si and Ni contents of this metal extract correspond to a silicate-metal equilibrium at high pressure (50±5 GPa) and high temperature (3500±500 °C), in line with a giant impact scenario. Mass balance calculations then yield the composition of the proto-core and the proto-mantle prior to the giant impact. We obtain that the core of the proto-Earth was almost devoid of oxygen, hence formed under lower pressure and temperature conditions, in agreement with an early differentiation of planetesimals in the early solar system. In such a two-stage scenario of Earth's core formation, no massive silicate differentiation is required to create a pristine mantle heterogeneity. The concentration of lithophile elements in the Primitive Lower mantle can then be constrained using RLE ratios in E-chondrites and in the upper mantle.

Kaminski, Edouard; Javoy, Marc

2013-03-01

154

Earth anchors  

CERN Document Server

Anchors are primarily used in the construction of foundations of earth-supported and earth-retaining structures. The anchors are used in construction to transmit the outwardly-directed load to soil at a greater depth and/or farther from the structure. Although earth anchors have been used in practice for several hundred years, proper theoretical developments for purposes of modern engineering design have taken place only during the past twenty years or so. This book summarizes most of the theoretical and experimental works directed toward the ultimate and allowable holding capacity of earth an

Das, BM

2012-01-01

155

Balance (or Vestibular) Rehabilitation  

Science.gov (United States)

... the Public › Hearing and Balance Balance (or Vestibular) Rehabilitation Audiologic (hearing), balance, and medical diagnostic tests help ... whether you are a candidate for vestibular (balance) rehabilitation. Vestibular rehabilitation is an individualized balance retraining exercise ...

156

Guided earth boring tool  

Energy Technology Data Exchange (ETDEWEB)

A controllable tool for drilling holes in the earth is described comprising a hollow elongated rigid supporting drill pipe having a forward end for entering the earth, means supporting the drill pipe for earth boring or piercing movement, including means for moving the drill pipe longitudinally for penetrating the earth, the drill pipe moving means being constructed to permit addition and removal of supporting drill pipe during earth penetrating operation, a boring mole supported on the forward end of the hollow low drill pipe comprising a cylindrical housing supported on and open to the forward end of the drill pipe, a first means on the front end for applying a boring force to the soil comprising an anvil having a striking surface inside the housing and a boring surface outside the housing, a second means comprising a reciprocally movable hammer positioned in the housing to apply a percussive force to the anvil striking surface for transmitting a percussive force to the boring force applying means, and means permitting introduction of air pressure supplied through the hollow pipe into the housing for operating the hammer and for discharging spent air from the housing to the hole being bored, and the tool being operable to penetrate the earth upon longitudinal movement of the drill rod by the longitudinal rod moving means and operation of the mole by reciprocal movement of the hammer.

Mc Donald, W.J.; Pittard, G.T.; Maurer, W.C.; Wasson, M.R.; Herben, W.C.

1987-09-22

157

Home health and home care in Massachusetts after the Balanced Budget Act of 1997: implications of cost containment pressures for service authorizations.  

UK PubMed Central (United Kingdom)

This paper explores the response of the Massachusetts state-funded home care program for the elderly when its clients encountered barriers to the receipt of home health services because of HMO enrollment and the implementation of the Balanced Budget Act of 1997. Clients of three regional case management agencies serving the Massachusetts state home care program whose home care services were interrupted because of hospitalization between January 1 and April 30, 1999 and whose services were resumed after they returned home were studied. Detailed data are reported that show how the long-term personal assistance services provided through the state program were often complemented by temporary home health services after elders returned home. The multivariate analysis revealed that the authorization of state-funded personal care services was keyed to the status of home health aide services. After hospitalization, the presence of a home health aide reduced the likelihood of authorization of personal care. At final assessment, the situation was reversed, that is, the withdrawal of a home health aide increased the likelihood of authorization of personal care. The findings suggest that more restrictive Medicare reimbursement policies for home health services led to greater state expenditures for personal care services. In other words, less generous Medicare financing shifted a greater portion of the burden of financing home care to the state of Massachusetts. These findings raise important policy questions about the balance of responsibility between the federal government and states to provide financing of home care services for the elderly.

Caro FG; Porell FW; Sullivan DM; Safran-Norton CE; Miltiades H

2002-01-01

158

Home health and home care in Massachusetts after the Balanced Budget Act of 1997: implications of cost containment pressures for service authorizations.  

Science.gov (United States)

This paper explores the response of the Massachusetts state-funded home care program for the elderly when its clients encountered barriers to the receipt of home health services because of HMO enrollment and the implementation of the Balanced Budget Act of 1997. Clients of three regional case management agencies serving the Massachusetts state home care program whose home care services were interrupted because of hospitalization between January 1 and April 30, 1999 and whose services were resumed after they returned home were studied. Detailed data are reported that show how the long-term personal assistance services provided through the state program were often complemented by temporary home health services after elders returned home. The multivariate analysis revealed that the authorization of state-funded personal care services was keyed to the status of home health aide services. After hospitalization, the presence of a home health aide reduced the likelihood of authorization of personal care. At final assessment, the situation was reversed, that is, the withdrawal of a home health aide increased the likelihood of authorization of personal care. The findings suggest that more restrictive Medicare reimbursement policies for home health services led to greater state expenditures for personal care services. In other words, less generous Medicare financing shifted a greater portion of the burden of financing home care to the state of Massachusetts. These findings raise important policy questions about the balance of responsibility between the federal government and states to provide financing of home care services for the elderly. PMID:12196934

Caro, Francis G; Porell, Frank W; Sullivan, Donna M; Safran-Norton, Clare E; Miltiades, Helen

2002-01-01

159

Earth tides  

Energy Technology Data Exchange (ETDEWEB)

Nineteen papers on gravity, tilt, and strain tides are compiled into this volume. Detailed chapters cover the calculation of the tidal forces and of the Earth's response to them, as well as actual observations of earth tides. Partial Contents: On Earth tides. The tidal forces: Tidal Forces. New Computations of the Tide-Generating Potential. Corrected Tables of Tidal Harmonics. The Theory of Tidal Deformations. Body Tides on an Elliptical, Rotating, Elastic and Oceanless Earth, Deformation of the Earth by Surface Loads. Gravimetric Tidal Loading Computed from Integrated Green's Functions. Tidal Friction in the Solid Earth. Loading Tides Versus Body Tides. Lunar Tidal Acceleration from Earth Satellite Orbit Analysis. Observations: gravity. Tidal Gravity in Britain: Tidal Loading and the Spatial Distribution of the Marine Tide. Tidal Loading along a Profile Europe-East Africa-South Asia-Australia and the Pacific Ocean. Detailed Gravity-Tide Spectrum between One and Four Cycles per Day. Observations: tilt and strain. Cavity and Topographic Effects in Tilt and Strain Measurement. Observations of Local Elastic Effects on Earth Tide Tilts and Strains.

Harrison, J.C.

1984-01-01

160

Aiming for a negative fluid balance in patients with acute lung injury and increased intra-abdominal pressure: a pilot study looking at the effects of PAL-treatment.  

UK PubMed Central (United Kingdom)

INTRODUCTION: Achievement of a negative fluid balance in patients with capillary leak is associated with improved outcome. We investigated the effects of a multi-modal restrictive fluid strategy aiming for negative fluid balance in patients with acute lung injury (ALI). METHODS: In this retrospective matched case-control study, we included 114 mechanically ventilated (MV) patients with ALI. We compared outcomes between a group of 57 patients receiving PAL-treatment (PAL group) and a matched control group, abstracted from a historical cohort. PAL-treatment combines high levels of positive end-expiratory pressure, small volume resuscitation with hyperoncotic albumin, and fluid removal with furosemide (Lasix®) or ultrafiltration. Effects on extravascular lung water index (EVLWI), intra-abdominal pressure (IAP), organ function, and vasopressor therapy were recorded during 1 week. The primary outcome parameter was 28-day mortality. RESULTS: At baseline, no significant intergroup differences were found, except for lower PaO2/FIO2 and increased IAP in the PAL group (174.5 ± 84.5 vs 256.5 ± 152.7, p = 0.001; 10.0 ± 4.2 vs 8.0 ± 3.7 mmHg, p = 0.013, respectively). After 1 week, PAL-treated patients had a greater reduction of EVLWI, IAP, and cumulative fluid balance (-4.2 ± 5.6 vs -1.1 ± 3.7 mL/kg, p = 0.006; -0.4 ± 3.6 vs 1.8 ± 3.8 mmHg, p = 0.007; -1,451 ± 7,761 vs 8,027 ± 5,254 mL, p < 0.001). Repercussions on cardiovascular and renal function were limited. PAL-treated patients required fewer days of intensive care unit admission and days on MV (23.6 ± 15 vs 37.1 ± 19.9 days, p = 0.006; 14.6 ± 10.7 vs 25.5 ± 20.2 days, respectively) and had a lower 28-day mortality (28.1% vs 49.1%, p = 0.034). CONCLUSION: PAL-treatment in patients with ALI is associated with a negative fluid balance, a reduction of EVLWI and IAP, and improved clinical outcomes without compromising organ function.

Cordemans C; De Laet I; Van Regenmortel N; Schoonheydt K; Dits H; Martin G; Huber W; Malbrain ML

2012-07-01

 
 
 
 
161

Magnetostrophic MRI in the Earth's Outer Core  

CERN Multimedia

We show that a simple, modified version of the Magnetorotational Instability (MRI) can develop in the outer liquid core of the Earth, in the presence of a background shear. It requires either thermal wind, or a primary instability, such as convection, to drive a weak differential rotation within the core. The force balance in the Earth's core is very unlike classical astrophysical applications of the MRI (such as gaseous disks around stars). Here, the weak differential rotation in the Earth core yields an instability by its constructive interaction with the planet's much larger rotation rate. The resulting destabilising mechanism is just strong enough to counteract stabilizing resistive effects, and produce growth on geophysically interesting timescales. We give a simple physical explanation of the instability, and show that it relies on a force balance appropriate to the Earth's core, known as magnetostrophic balance.

Petitdemange, Ludovic; Balbus, Steven A

2009-01-01

162

Estudio experimental y numérico del desplazamiento y rotación de suelo reforzado con geomallas bajo empuje activo/ Experimental and numerical study of the displacement and rotation of geogrid reinforced soil under active lateral earth pressure  

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish Se presenta un estudio experimentaly numérico de desplazamiento y rotación de suelo sin y con refuerzo de geomallas bajo la acción del empuje activo. Para ello se ha usado la técnica de medición PIV con la cual se procesan imágenes digitales para la obtención de campos de desplazamiento y rotación. El equipo de ensayo de empuje posee una ventana transparente que permite registrar el movimiento del suelo. Los resultados medidos de movimiento del suelo permiten dete (more) rminar áreas de suelo que fluyen y no fluyen debido a la acción del empuje activo. De esta manera se puede determinar la posición y geometría de la superficie de falla, la cual se puede comparar con la definida por la teoría de la plasticidad de empuje activo de Rankine. Esta comparación resulta solo posible para el caso sin geomallas, dado que con geomallas la zona de suelo en fluencia cambia significativamente. La presencia de geomallas puede reducir hasta dos veces el volumen de suelo que entra en fluencia debido al empuje activo. Esta conclusión relacionada con la deformación del suelo está en directa relación con la disminución de la tensión de empuje activo al utilizar geomallas como elementos de refuerzo. También se presenta un análisis numérico usando el programa computacional Plaxis para estimar los desplazamientos horizontales. Los resultados numéricos entregan estimaciones que se aproximan a los resultados medidos de desplazamientos horizontales en términos de la forma de la zona de suelo en fluencia. Sin embargo, no son capaces de reproducir en detalle la geometría de la superficie de falla. Abstract in english An experimental and numerical study is presented related to displacement and rotation of soil with and without geogrid reinforcement under the application of active lateral earth pressure. To this end, the measurement technique PIV has been used, with which digital images are processed to obtain displacement and rotation fields. The experimental earth pressure equipment has a transparent window which allows the recording of soil movements. Through the process and analysis (more) of the measured soil movement, soil areas which yielded and did not yield due to the active earth pressure, were defined. In this form, the position and geometry of the failure surface can be determined and compared with the defined by the plasticity theory of active Rankine states. This comparison is only possible for the case without geogrids since the presence of geogrids change significantly the zone of soil yielding. Geogrids can reduce up to twice the volume of soil yielding due to the active lateral earth pressure. This conclusion related with the soil deformation is in direct relation with the active lateral earth pressure reduction when geogrids are used as reinforced elements. In addition, a numerical analysis using the computational program Plaxis is presented to estimate horizontal displacements. The numerical results estimate reasonably well the horizontal displacements measured in terms of the shape of the soil yielding area. However, they do not reproduce in detail the geometry of the failure surface.

Ruiz-Tagle, Lissette; Villalobos, Felipe

2011-01-01

163

Estudio experimental y numérico del desplazamiento y rotación de suelo reforzado con geomallas bajo empuje activo Experimental and numerical study of the displacement and rotation of geogrid reinforced soil under active lateral earth pressure  

Directory of Open Access Journals (Sweden)

Full Text Available Se presenta un estudio experimentaly numérico de desplazamiento y rotación de suelo sin y con refuerzo de geomallas bajo la acción del empuje activo. Para ello se ha usado la técnica de medición PIV con la cual se procesan imágenes digitales para la obtención de campos de desplazamiento y rotación. El equipo de ensayo de empuje posee una ventana transparente que permite registrar el movimiento del suelo. Los resultados medidos de movimiento del suelo permiten determinar áreas de suelo que fluyen y no fluyen debido a la acción del empuje activo. De esta manera se puede determinar la posición y geometría de la superficie de falla, la cual se puede comparar con la definida por la teoría de la plasticidad de empuje activo de Rankine. Esta comparación resulta solo posible para el caso sin geomallas, dado que con geomallas la zona de suelo en fluencia cambia significativamente. La presencia de geomallas puede reducir hasta dos veces el volumen de suelo que entra en fluencia debido al empuje activo. Esta conclusión relacionada con la deformación del suelo está en directa relación con la disminución de la tensión de empuje activo al utilizar geomallas como elementos de refuerzo. También se presenta un análisis numérico usando el programa computacional Plaxis para estimar los desplazamientos horizontales. Los resultados numéricos entregan estimaciones que se aproximan a los resultados medidos de desplazamientos horizontales en términos de la forma de la zona de suelo en fluencia. Sin embargo, no son capaces de reproducir en detalle la geometría de la superficie de falla.An experimental and numerical study is presented related to displacement and rotation of soil with and without geogrid reinforcement under the application of active lateral earth pressure. To this end, the measurement technique PIV has been used, with which digital images are processed to obtain displacement and rotation fields. The experimental earth pressure equipment has a transparent window which allows the recording of soil movements. Through the process and analysis of the measured soil movement, soil areas which yielded and did not yield due to the active earth pressure, were defined. In this form, the position and geometry of the failure surface can be determined and compared with the defined by the plasticity theory of active Rankine states. This comparison is only possible for the case without geogrids since the presence of geogrids change significantly the zone of soil yielding. Geogrids can reduce up to twice the volume of soil yielding due to the active lateral earth pressure. This conclusion related with the soil deformation is in direct relation with the active lateral earth pressure reduction when geogrids are used as reinforced elements. In addition, a numerical analysis using the computational program Plaxis is presented to estimate horizontal displacements. The numerical results estimate reasonably well the horizontal displacements measured in terms of the shape of the soil yielding area. However, they do not reproduce in detail the geometry of the failure surface.

Lissette Ruiz-Tagle; Felipe Villalobos

2011-01-01

164

Earth Day  

Science.gov (United States)

The State University of New York at Buffalo presents this History of Earth Day website. The goal of the site is that teachers and students can better understand the development and purpose of Earth Day. In addition to the history, SUNY-Buffalo has compiled a series of websites complete with projects associated with Earth Day, appropriate for children, high school students, and college undergrads. Furthermore, the legal aspect of Earth Day - environmental legislation, EPA standards, and Global Climate Change legislation - are also discussed on the site. A list of further sites is also provided if users want more information on this national effort to help solve environmental issues such as pollution, overpopulation, and global warming. Teachers will find this website both informative and helpful in developing appropriate teaching curricula connected to this holiday, while students can have fun learning and creating projects of their own that contribute to preserving the environment.

2007-04-19

165

Carbon and nitrogen balance in beech roots under competitive pressure of soil-borne microorganisms induced by girdling, drought and glucose application  

UK PubMed Central (United Kingdom)

The goal of this work was to increase the understanding of factors regulating nitrogen (N) competition between roots and soil microbes. For this purpose, root assimilate supply was diminished or abolished in beech (Fagus sylvatica L.) seedlings by girdling, drought stress or a combination of both factors. This was revealed by ¹³C tracer abundance in root tips after ¹³CO? pulse labelling of the shoots. Analysis of different root tip fractions revealed that only 6% were ectomycorrhizal. Carbon (C) allocation to ectomycorrhizal and vital non-mycorrhizal root tips was ~26% higher than to distorted root tips. Drought resulted in ~30% increased ammonium (NH??) and amino acid concentrations in roots and ~65% increased soil NH?? concentrations, probably because of lower consumption of NH?? by free-living microorganisms. Root uptake of glutamine of 13nmolg?¹ fresh mass h?¹ decreased 2-fold with drought, although the number of vital root tips did not decrease. Carbon content in biomass of free-living microbes increased with glucose application regardless of drought, resulting in significant depletion in soil nitrate (NO??), root NH?? and amino acid concentrations. Our results suggest that the root-soil system of young beech trees was C-limited, and this prevented amino acid metabolism in roots and microbial NO?? consumption in the soil, thereby exerting feedback inhibition on uptake of inorganic N by roots. We suggest that rhizodeposition is a key link in regulating the plant-microbial N balance.

Winkler JanaB; Dannenmann Michael; Simon Judy; Pena Rodica; Offermann Christine; Sternad Wolfgang; Clemenz Christian; Naumann PascaleS; Gasche Rainer; Kögel-Knabner Ingrid; Gessler Arthur; Rennenberg Heinz; Polle Andrea

2010-01-01

166

Rare earths  

International Nuclear Information System (INIS)

The participants in the conference heard 22 papers of which 14 are inputted in INIS. They discussed the technology of the separation of rare earth elements, extraction separation and refining of lanthanides, thorium sorption from bastnaesite eluates using ion exchangers, various methods of separating Eu, radioanalytical methods and the use of plasma emission analysis in determining rare earth elements. (E.J.). 4 figs., 10 tabs., 18 refs.

1989-01-01

167

Paternity Balancing.  

UK PubMed Central (United Kingdom)

Background: Gestational carriers and egg donors have been used by 'traditional' and now increasingly, gay couples. Three gay male couples, all using egg donors and gestational carriers with semen from both partners, had triplets. All desired reductions to twins for the standard medical indications, but requested, if reasonably possible, to have twins with one fathered by each partner. Methods: Following our usual clinical protocol, we performed chorionic villus sampling at 12 weeks on all fetuses obtaining FISH and karyotype. For paternity analysis, 14 polymorphic molecular markers on villi were compared to DNA samples from the two men to include or exclude each. Results: Standard assessments were all normal. Paternity testing showed that one partner fathered two of the triplets, and the other one. In all cases, one of the 'twins' was reduced with good clinical outcomes ensuing. Conclusions: Paternity balancing increases options for satisfying family planning desires of gay male couples. We believe it comparable to gender preferences in reductions, i.e. it can be considered but only completely subservient to any clinical criteria. Paternity balancing raises similar ethical issues as reduction with gender preferences, but may increase patient autonomy and mainstream acceptance of stable, gay families.

Evans MI; Andriole S; Pergament E; Speer J; Curtis J; Britt DW

2013-08-01

168

Ballet Balance Strategies  

DEFF Research Database (Denmark)

Animating physically realistic human characters is challenging, since human observers are highly tuned to recognize human cues such as emotion and gender from motion patterns. The main contribution of this paper is a new model firmly based on biomechanics, which is used to animate balance and basic movements of a ballet dancers. It is supported by computer simulated experiments and it is in good agreement with biomechanical measurements of real-life dancers. Our results questions the previous approaches in dynamic animation, which only uses the center of gravity strategy, and instead demonstrate the viability of the center of pressure strategy.

Pedersen, Camilla; Erleben, Kenny

2006-01-01

169

Titan's Greenhouse Effect And Climate: Lessons From The Earth's Cooler Cousin  

Science.gov (United States)

We argue that continuing scientific study of Earth's `distant cousin’ Titan can provide a greater understanding and insight into the energy balance of our own planet's atmosphere. Titan's Earth-like properties have been recognized for some time, from the discovery of its atmosphere in 1907, through the Voyager 1 encounter in 1980 that showed Titan's atmosphere is mostly nitrogen gas with a surface pressure within a factor of two of terrestrial. Calculation shows that Titan's atmosphere causes `greenhouse’ warming of the surface, an effect similar to that seen on the Earth, Mars, and Venus. In the 1990s, direct imaging from the Earth by adaptive optics revealed that Titan's ubiquitous haze layer is slowly changing in apparent response to the seasons that occur due to the Saturn system's obliquity. The NASA Cassini mission that arrived in Saturnian orbit in 2004, and the ESA Huygens Titan probe of 2005, have returned a flood of new data regarding this intriguing world. For the first time, we are building a detailed picture of weather in the lower atmosphere, where condensable methane takes on the role played by water in the Earth's atmosphere, leading to methane rainfall, rivers and lakes. We examine parallels between the atmospheres of Earth and of Titan, including the possibilities for dramatic climate change. Extending the duration of the Cassini spacecraft mission during the next decade will provide part of the needed picture, but in addition we urge planning for a future new mission focused on Titan's climate, and other measures.

Nixon, Conor A.; Titan Climate White Paper Proposal Team

2009-12-01

170

Burnup of UO2-Gd2O3 nuclear fuel elements. Separation of gadolinium from rare earths by high pressure liquid chromatography (HPLC)  

International Nuclear Information System (INIS)

[en] In the framework of a research project on burnable poisons, a technique to separate gadolinium from irradiated samples of (U-Gd)O2+x has been developed in order to determine the burnup of mixed oxides fuel elements. The separation of Gd from the other rare earths (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) has been carried out by HPLC after uranium extraction with TBP. The procedure can be applied as a step to determine the burnup of spent nuclear fuels

1999-01-01

171

Theoretical Study on the Electrical Properties of Some Semiconducting Rare Earth Chalcogenides Sm1 – XEuxS and Sm1 – Xybxs Under Pressure  

Directory of Open Access Journals (Sweden)

Full Text Available A theoretical study on semiconductor rare earth chalcogenides Sm1 – xEuxS and Sm1 – x YbxS has been made for deducing electrical transport properties using only two parameters, namely lattice constant and activation energy. The calculated electrical properties electrical resistivity, carrier mobility, carrier concentration, carrier effective mass and dielectric constant are compared with the available experimental results. They are found to be in good agreement with each other. Then, the limitation of this theoretical study has also been discussed in this paper.

S. Ariponnammal; S. Chandrasekaran

2011-01-01

172

Shaft balancing  

Science.gov (United States)

A gas turbine engine has an internal drive shaft including one end connected to a driven load and an opposite end connected to a turbine wheel and wherein the shaft has an in situ adjustable balance system near the critical center of a bearing span for the shaft including two 360.degree. rings piloted on the outer diameter of the shaft at a point accessible through an internal engine panel; each of the rings has a small amount of material removed from its periphery whereby both of the rings are precisely unbalanced an equivalent amount; the rings are locked circumferentially together by radial serrations thereon; numbered tangs on the outside diameter of each ring identify the circumferential location of unbalance once the rings are locked together; an aft ring of the pair of rings has a spline on its inside diameter that mates with a like spline on the shaft to lock the entire assembly together.

Irwin, John A. (Greenwood, IN)

1979-01-01

173

Wellbore pressure transducer  

Science.gov (United States)

Subterranean earth formations containing energy values are subjected to hydraulic fracturing procedures to enhance the recovery of the energy values. These fractures are induced in the earth formation by pumping liquid into the wellbore penetrating the earth formation until the pressure of the liquid is sufficient to fracture the earth formation adjacent to the wellbore. The present invention is directed to a transducer which is positionable within the wellbore to generate a signal indicative of the fracture initiation useful for providing a timing signal to equipment for seismic mapping of the fracture as it occurs and for providing a measurement of the pressure at which the fracture is initiated.

Shuck, Lowell Z. (Morgantown, WV)

1979-01-01

174

Development of high temperature reference electrodes for in-pile application: Part I. Feasibility study of the external pressure balanced Ag/AgCl reference electrode (EPBRE) and the cathodically charged Palladium hydrogen electrode  

Energy Technology Data Exchange (ETDEWEB)

The main problems connected with corrosion potential measurements at elevated temperatures and pressures are related to the stability and lifetime of the reference electrode and the correct estimation of the potential related to the Standard Hydrogen Scale (SHE). Under Pressurised Water Reactor (PWR) conditions of 300 degrees Celsius and 150 bar, the choice of materials is also a limiting factor due to the influence of radiation. Investigations on two reference electrodes that can be used under PWR conditions are reported: the cathodically charged palladium hydrogen electrode, and the external pressure balanced silver/silver chloride electrode. Preliminary investigations with the Pd-electrode were focused on the calculation of the required charging time and the influence of dissolved oxygen. High temperature applications are discussed on the basis of results reported in the literature. Investigations with the silver/silver chloride reference electrode mainly dealt with the salt bridge which is necessary to connect the reference electrode with the testing solution. It is shown that the thermal junction potential is independent of the length of the salt bridge. In addition, the high temperature contributes to an increase of the conductivity of the solution, which is beneficial for the salt bridge connection.

Bosch, R.W.; Van Nieuwenhove, R

1998-10-01

175

Formation of high-precision volume-of-fluid method establishing appropriate balance between pressure and surface tension and its application to gas entrainment phenomena in fast breeder reactors  

International Nuclear Information System (INIS)

To evaluate directly gas entrainment (GE) phenomena in fast breeders, we have been studied a numerical simulation method based on a high-precision volume-of-fluid (VOF) methodology. In addition, we have been employed unstructured meshes to subdivide simulation domains because exact modeling of complicated geometries in each simulation domain is a key to simulate gas entrainment phenomena accurately. Therefore, as important parts of our study, formulations of each calculation procedure in the high-precision VOF methodology on unstructured meshes are conducted in this paper. In concrete terms, calculation procedures for 1) interfacial gradient vectors, 2) interface reconstructions, 3) fluxes of volume fraction on each mesh cell face are formulated on unstructured meshes. Calculation procedures of Surface tension forces are also formulated in this paper. Then, unphysical behaviors of velocity distributions near gas-liquid interface induced by inappropriate formulation of pressure gradient are discussed and an appropriate formulation is derived considering proper balance conditions between pressure and surface tension forces. It is confirmed that this new formulation reduces the unphysical behaviors in a numerical simulation of a rising gas bubble in liquid. Finally, the basic GE experiment is simulated using our numerical simulation method. The simulation results shows that the GE phenomena occurs in the same mechanism with the experimental results. (author)

2008-01-01

176

THE COSMIC-RAY INTENSITY NEAR THE ARCHEAN EARTH  

Energy Technology Data Exchange (ETDEWEB)

We employ three-dimensional state-of-the-art magnetohydrodynamic models of the early solar wind and heliosphere and a two-dimensional model for cosmic-ray transport to investigate the cosmic-ray spectrum and flux near the Archean Earth. We assess how sensitive the cosmic-ray spectrum is to changes in the sunspot placement and magnetic field strength, the large-scale dipole magnetic field strength, the wind ram pressure, and the Sun's rotation period. Overall, our results confirm earlier work that suggested the Archean Earth would have experienced a greatly reduced cosmic-ray flux than is the case today. The cosmic-ray reduction for the early Sun is mainly due to the shorter solar rotation period and tighter winding of the Parker spiral, and to the different surface distribution of the more active solar magnetic field. These effects lead to a global reduction of the cosmic-ray flux at 1 AU by up to two orders of magnitude or more. Variations in the sunspot magnetic field have more effect on the flux than variations in the dipole field component. The wind ram pressure affects the cosmic-ray flux through its influence on the size of the heliosphere via the pressure balance with the ambient interstellar medium. Variations in the interstellar medium pressure experienced by the solar system in orbit through the Galaxy could lead to order of magnitude changes in the cosmic-ray flux at Earth on timescales of a few million years.

Cohen, O.; Drake, J. J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Kota, J. [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721-0092 (United States)

2012-11-20

177

Pressure effects on magnetic properties of R(Fe, M)12 single crystals (R=rare earth, M=Ti, Mo)  

International Nuclear Information System (INIS)

[en] The saturation magnetization of the RFe11Ti (R=Y, Ho, Dy) and RFe10.5Mo1.5 (R=Y, Er) single crystals was measured under high pressure up to 9 kbar in the temperature range 5-300 K. A reduction of Fe-moment mFe under pressure is largely affected by the stabilizing elements Ti or Mo in the isostructural YFe11Ti (dln mFe/dp=-3.4x10-3 kbar-1) and YFe10.5 Mo1.5 (dln mFe/dp=-8.6x10-3 kbar-1) compounds. The critical field of the first-order magnetization process in HoFe11Ti increases significantly under pressure at 5 K. These effects can be ascribed to an increase of hybridization of Fe and Mo d-band under pressure and to an influence of pressure on the 4f-sublattice anisotropy, respectively

2001-01-01

178

Balanced Cayley graphs and balanced planar graphs  

CERN Multimedia

A balanced graph is a bipartite graph with no induced circuit of length 2 mod 4. These graphs arise in linear programming. We focus on graph-algebraic properties of balanced graphs to prove a complete classification of balanced Cayley graphs on abelian groups. Moreover, in Section 5 of this paper, we prove that there is no cubic balanced planar graph. Finally, some remarkable conjectures for balanced regular graphs are also presented.

Morris, Joy; Webb, Kerri

2007-01-01

179

Magnetic hyperfine fields acting on diamagnetic119Sn impurity in rare-earth-3d transition metal laves phases, crystallized under high pressure  

Science.gov (United States)

A summary of the magnetic and the electronic properties of Laves Phases compounds RT2 (R=Sm-Lu; T=Fe, Co, Ni) synthesized under high pressure is presented. The hyperfine fields acting on tin impurity nuclei in RT2 have been obtained by Mössbauer spectroscopy. It has been found that hyperfine fields at119Sn and their temperature dependences for the RFe2 (R=Sm-Ho), the RCo2 (R=Sm-Tb) and GdNi2 prepared at high and atmospheric pressures, are substantially different, respectively.

Tsvyashchenko, A. V.; Krylov, V. I.

1990-08-01

180

Chronic blood pressure control.  

UK PubMed Central (United Kingdom)

Chronic blood pressure is maintained within very narrow limits around an average value. However, the multitude of physiologic processes that participate in blood pressure control present a bewildering array of possibilities to explain how such tight control of arterial pressure is achieved. Guyton and Coleman and colleagues addressed this challenge by creating a mathematical model that integrated the short- and long-term control systems for overall regulation of the circulation. The hub is the renal-body fluid feedback control system, which links cardiac function and vascular resistance and capacitance with fluid volume homeostasis as the foundation for chronic blood pressure control. The cornerstone of that system is renal sodium excretory capability, which is defined by the direct effect of blood pressure on urinary sodium excretion, that is, "pressure natriuresis." Steady-state blood pressure is the pressure at which pressure natriuresis balances sodium intake over time; therefore, renal sodium excretory capability is the set point for chronic blood pressure. However, this often is misinterpreted as dismissing, or minimizing, the importance of nonrenal mechanisms in chronic blood pressure control. This article explains the renal basis for the blood pressure set point by focusing on the absolute dependence of our survival on the maintenance of sodium balance. Two principal threats to sodium balance are discussed: (1) a change in sodium intake or renal excretory capability and (2) a change in blood pressure. In both instances, circulatory homeostasis is maintained because the sodium balance blood pressure set point is reached.

Brands MW

2012-10-01

 
 
 
 
181

Water and sodium balance in space  

DEFF Research Database (Denmark)

We have previously shown that fluid balances and body fluid regulation in microgravity (microG) differ from those on Earth (Drummer et al, Eur J Physiol 441:R66-R72, 2000). Arriving in microG leads to a redistribution of body fluid-composed of a shift of fluid to the upper part of the body and an exaggerated extravasation very early in-flight. The mechanisms for the increased vascular permeability are not known. Evaporation, oral hydration, and urinary fluid excretion, the major components of water balance, are generally diminished during space flight compared with conditions on Earth. Nevertheless, cumulative water balance and total body water content are stable during flight if hydration, nutritional energy supply, and protection of muscle mass are at an acceptable level. Recent water balance data disclose that the phenomenon of an absolute water loss during space flight, which has often been reported in the past, is not a consequence of the variable microG. The handling of sodium, however, is considerably affected by microG. Sodium-retaining endocrine systems, such as renin-aldosterone and catecholamines, are much more activated during microG than on Earth. Despite a comparable oral sodium supply, urinary sodium excretion is diminished and a considerable amount of sodium is retained-without accumulating in the intravascular space. An enormous storage capacity for sodium in the extravascular space and a mechanism that allows the dissociation between water and sodium handling likely contribute to the fluid balance adaptation in weightlessness.

Drummer, C; Norsk, P

2001-01-01

182

Water Cycling Between Ocean and Mantle: Super-Earths Need Not be Waterworlds  

Science.gov (United States)

Simple scaling relations dictate that ocean depth should increase with planetary mass, with the generic prediction that large terrestrial planets should be entirely covered in water, so-called waterworlds. Water is partitioned, however, between a surface reservoir, the ocean, and an interior reservoir, the mantle. If a planet undergoes plate tectonics, then water can move between these reservoirs on geological timescales: ocean crust formation at mid-ocean ridges releases water into the ocean, while subduction of serpentinized crust carries water into the mantle. Motivated by Earth's approximately steady-state deep water cycle, we develop a two-box model of the hydrosphere including potential feedbacks from sea-floor pressure, as well as the effects of isostatic adjustment. Using this model, we derive analytic and numerical steady-state solutions to the water-partitioning on terrestrial planets. We show that isostatic adjustment allows for a wide range of ocean volumes without submerging continents. Since surface gravity does not affect the steady state isostatic balance, this leeway applies just as well to super-Earths, despite their reduced topography. Moreover, the deep water cycle is mediated by sea-floor pressure, which is proportional to gravity. Super-Earths with a deep water cycle should therefore store the majority of their water in the mantle. We conclude that tectonically active planets with water mass fractions below about 0.004 will have exposed continents like Earth.

Cowan, Nicolas B.; Abbot, D. S.

2013-10-01

183

Breathing Earth  

Science.gov (United States)

Visual simulation and representation programs and applications have been popping up online in greater numbers, and this recent find is one that will pique the interest of scientists, policy makers, and others who are concerned about carbon dioxide emission rates across the Earth. The Breathing Earth site was created by David Bleja, and he draws on a number of resources (such as the World Factbook and the United Nations) for the data that is utilized to create this site. Visitors can scroll over different countries to learn about their population, their emissions, and their birth and death rate. This interactive map and educational resource also contains a legend in the right-hand corner which explains the various symbols in use here.

Bleja, David

184

Earth's Biomes  

Science.gov (United States)

What are the characteristics of Earth's biomes? First, open the Biomes Graphic Organizer Now read through Information on Aquatic Biome (Freshwater) and fill in 5 characterestics of a freshwater biome in your graphic organizer. Now read through Information on Desert and fill in 5 characteristics of a desert biome in your graphic organizer. Now read through Information on Rainforest and fill in 5 characteristics of rainforest biome in your graphic organizer. Now ...

Allman, Ms.

2012-04-05

185

New high pressure rare earth tantalates RExTa2O5+1.5x (RE=La, Eu, Yb)  

Science.gov (United States)

Rare earth tantalates La0.075Ta2O5.113, Eu0.089Ta2O5.134 and Yb0.051Ta2O5.077 have been prepared by solid state reaction at P=7.0 GPa and T=1050-1100 °C and studied by X-ray diffraction, thermal analysis and electron microscopy. Low hydrated amorphous tantalum, lanthanum, europium and ytterbium hydroxides were used as starting materials. Aqueous as well as anhydrous compounds were obtained. Title tantalates are crystallized in the structure type of F-Ta2O5 [Zibrov et al. Russ. J. Inorg. Chem. 48 (2003) 464-471] [5]. The structure was refined by the Rietveld method from X-ray powder diffractometer data: La0.075Ta2O5.113, a=10.5099(2), b=7.2679(1), c=6.9765(1) Å, V=532.90(1) Å3, Z=6, space group Ibam; Eu0.089Ta2O5.134, a=10.4182(3), b=7.2685(1), c=6.9832(1) Å, V=528.80(2) Å3, Z=6, space group Ibam; Yb0.051Ta2O5.077, a=10.4557(2), b=7.3853(1), c=6.8923(1) Å, V=532.21(1) Å3, Z=6, space group Ibam. RE atoms do not replace the tantalum in its positions but the only water in the channels of the structure. Highly charged cations RE+3 compress the unit cell so that its volume becomes less than that of F-Ta2O5. Significant decrease of the unit cell volume after water removal from the structure is possible due to the puckering of pentagonal bipyramid layers and change of the corrugation angle in the layer.

Zibrov, Igor P.; Filonenko, Vladimir P.; Zakharov, Nikolai D.; Werner, Peter; Drobot, Dmitrii V.; Nikishina, Elena E.; Lebedeva, Elena N.

2013-07-01

186

Effect of mass disorder on the lattice thermal conductivity of MgO periclase under pressure.  

UK PubMed Central (United Kingdom)

Thermal conductivity of mantle materials controlling the heat balance and thermal evolution of the Earth remains poorly constrained as the available experimental and theoretical techniques are limited in probing minerals under the relevant conditions. We report measurements of thermal conductivity of MgO at high pressure up to 60?GPa and 300?K via diamond anvil cells using the time-domain thermoreflectance technique. These measurements are complemented by model calculations which take into account the effect of temperature and mass disorder of materials within the Earth. Our model calculations agree with the experimental pressure dependencies at 300 and 2000?K for MgO. Furthermore, they predict substantially smaller pressure dependence for mass disordered materials as the mechanism of scattering changes. The calculated thermal conductivity at the core-mantle boundary is smaller than the majority of previous predictions resulting in an estimated total heat flux of 10.4?TW, which is consistent with modern geomodeling estimates.

Dalton DA; Hsieh WP; Hohensee GT; Cahill DG; Goncharov AF

2013-08-01

187

Effect of mass disorder on the lattice thermal conductivity of MgO periclase under pressure.  

Science.gov (United States)

Thermal conductivity of mantle materials controlling the heat balance and thermal evolution of the Earth remains poorly constrained as the available experimental and theoretical techniques are limited in probing minerals under the relevant conditions. We report measurements of thermal conductivity of MgO at high pressure up to 60?GPa and 300?K via diamond anvil cells using the time-domain thermoreflectance technique. These measurements are complemented by model calculations which take into account the effect of temperature and mass disorder of materials within the Earth. Our model calculations agree with the experimental pressure dependencies at 300 and 2000?K for MgO. Furthermore, they predict substantially smaller pressure dependence for mass disordered materials as the mechanism of scattering changes. The calculated thermal conductivity at the core-mantle boundary is smaller than the majority of previous predictions resulting in an estimated total heat flux of 10.4?TW, which is consistent with modern geomodeling estimates. PMID:23929068

Dalton, Douglas Allen; Hsieh, Wen-Pin; Hohensee, Gregory T; Cahill, David G; Goncharov, Alexander F

2013-08-01

188

Respiration effect on standing balance.  

UK PubMed Central (United Kingdom)

An attempt was made to determine the effect of respiration on standing balance. Ten able-bodied subjects were asked to stand upright on a force platform and were asked to hold their breath after inspiration and after expiration, and to breathe regularly, 4, 6, and 8 respirations per 20 seconds. Sway was measured over 20-second periods with eyes open and eyes closed. The results show that both respiration and eye condition affect the sway distance of the center of pressure on body balance. The sway distance in holding breath after inspiration is significantly greater than in holding breath after expiration, and increasing the respiration rate produces a greater postural sway. Also, the grade of visual compensation for body balance is higher in the regular respiration condition than in breath holding. These findings are applicable for ergonomics, sports, and clinical situations.

Jeong BY

1991-08-01

189

Fluid balance, renal function, and blood pressure.  

UK PubMed Central (United Kingdom)

After many detours in the search for the basic mechanism of hypertension, evidence now seems to corroborate the earliest concept that developed in the 1800's, namely, that hypertension almost always results from a tendency of the kidneys to retain water and salt. Animal studies show that the amount of excess body water and salt required to cause hypertension is exceedingly small, and that the hypertensive effect of the excess water and salt may not develop for days or weeks. When vascular constriciton occurs simultaneously, as occurs in the presence of large quantities of angiotensin, the blood volume may be less than normal, but even in these circumstances the fluid volume is relatively increased and is responsible for the hypertension because the vascular constrictont has decreased the capacity of the circulation to a greater extent than the decrease in blood volume.

Guyton AC; Young DB; DeClue JW; Trippodo N; Hall JE

1975-10-01

190

Toroidal and poloidal Alfvén waves with arbitrary azimuthal wavenumbers in a finite pressure plasma in the Earth's magnetosphere  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, in terms of an axisymmetric model of the magnetosphere, we formulate the criteria for which the Alfvén waves in the magnetosphere can be toroidally and poloidally polarized (the disturbed magnetic field vector oscillates azimuthally and radially, respectively). The obvious condition of equality of the wave frequency ? to the toroidal (poloidal) eigenfrequency ?TN (?PN) is a necessary and sufficient one for the toroidal polarization of the mode and only a necessary one for the poloidal mode. In the latter case we must also add to it a significantly stronger condition ??TN–?PN?/?TN ? m–1 where m is the azimuthal wave number, and N is the longitudinal wave number. In cold plasma (the plasma to magnetic pressure ratio ? = 0) the left-hand side of this inequality is too small for the routinely recorded (in the magnetosphere) second harmonic of radially polarized waves, therefore these waves must have nonrealistically large values of m. By studying several models of the magnetosphere differing by the level of disturbance, we found that the left-hand part of the poloidality criterion can be satisfied by taking into account finite plasma pressure for the observed values of m ? 50 – 100 (and in some cases, for even smaller values of the azimuthal wave numbers). When the poloidality condition is satisfied, the existence of two types of radially polarized Alfvén waves is possible. In magnetospheric regions, where the function ?PN is a monotonic one, the mode is poloidally polarized in a part of its region of localization. It propagates slowly across magnetic shells and changes its polarization from poloidal to toroidal. The other type of radially polarized waves can exist in those regions where this function reaches its extreme values (ring current, plasmapause). These waves are standing waves across magnetic shells, having a poloidal polarization throughout the region of its existence. Waves of this type are likely to be exemplified by giant pulsations. If the poloidality condition is not satisfied, then the mode is toroidally polarized throughout the region of its existence. Furthermore, it has a resonance peak near the magnetic shell, the toroidal eigenfrequency of which equals the frequency of the wave. Key words. Magnetospheric physics (plasmasphere; MHD waves and instabilities) – Space plasma physics (kinetic and MHD theory)

D. Yu. Klimushkin; P. N. Mager; K.-H. Glassmeier

2004-01-01

191

Earth 911  

Science.gov (United States)

Earth 911 is an organization focused on empowering the public with community-specific resources to improve their quality of life. To accomplish this goal, they provide information on a wide range of environmental topics including recycling (several types of materials), household hazardous waste, water quality, composting, air pollution prevention, fire prevention, green shopping tips, and mercury pollution. Environmental news links, games and activities for kids, and local news and events are also included. Users may enter a zip code to obtain information on environmental issues specific to where they live.

2004-01-01

192

Carbon cycles on super-Earth exoplanets  

Science.gov (United States)

On Earth, the long-term global carbon cycle primarily consists of a balance between volcanic emissions of CO2 and the formation and burial of carbonate rocks (the carbonate-silicate weathering 'thermostat'), with important modifications due to the biosphere. On gas giant planets, the carbon cycle is driven by photolysis in the upper atmosphere: methane is converted to longer-chain hydrocarbons such as acetylene, ethane and soot particles, which are then dissociated by thermolysis lower in the atmosphere where the temperature and pressure are much higher. Hydrogen escape rates on terrestrial exoplanets are predicted to be a strong function of their orbital distances, ages and masses. In particular, larger exoplanets around stars with lower extreme ultraviolet (XUV) emissions may have significant difficulties in losing their hydrogen to space, and hence may retain H2 envelopes of varying mass. It is therefore interesting to investigate what happens in the transition between the terrestrial and hydrogen-dominated regimes. Here we present a first attempt to investigate the range of scenarios that occur for terrestrial mass (~1-10 ME) planets with varying hydrogen escape rates. We are developing climate evolution simulations for a range of cases that account for surface processes (primarily outgassing and weathering), hydrogen escape to space, and simple atmospheric chemistry. We discuss various feedbacks that may occur as a result of the influences of CO2, CH4 and H2 on atmospheric and surface temperatures. Finally, we discuss the implications of our results for future observations, with a particular emphasis on the search for biosignatures on exoplanets similar to the Earth.

Wordsworth, Robin; Pierrehumbert, Raymond; Hébrard, Eric

2013-04-01

193

Synthesis of rare earth monoxides  

Energy Technology Data Exchange (ETDEWEB)

The standard Gibbs energy changes for the formation of an ionic or metallic monoxide from rare earth metal and sesquioxide have been calculated. Under high pressures ionic ytterbium monoxide and lighter rare earth metallic monoxides should be obtained, which is confirmed by experiments in a belt-type apparatus in the range 15 to 80 kbar and 500-1200/sup 0/C. For Ln = La, Ce, Pr, Nd, Sm, a face-centered cubic compound is obtained from each reaction. The cell parameters are respectively 5.144, 5.089, 5.031, 4.994, and 4.943 +- 0.005 A. The compounds appear golden yellow with a metallic luster. From chemical analyses and cell parameter consideration it is concluded that these compounds are the rare earth monoxides. For Ln = Gd, Dy, Tm, no reaction is observed at 50 kbar and 1000/sup 0/C. The rare earth monoxides show a variety of properties: LaO, CeO, PrO, and NdO are metallic with the rare earth in the trivalent state; EuO and YbO are semiconductors with the rare earth in the divalent state; SmO is metallic with samarium in an intermediate valence state close to 3.

Leger, J.M.; Yacoubi, N.; Loriers, J.

1981-03-01

194

Synthesis of rare earth monoxides  

International Nuclear Information System (INIS)

The standard Gibbs energy changes for the formation of an ionic or metallic monoxide from rare earth metal and sesquioxide have been calculated. Under high pressures ionic ytterbium monoxide and lighter rare earth metallic monoxides should be obtained, which is confirmed by experiments in a belt-type apparatus in the range 15 to 80 kbar and 500-12000C. For Ln = La, Ce, Pr, Nd, Sm, a face-centered cubic compound is obtained from each reaction. The cell parameters are respectively 5.144, 5.089, 5.031, 4.994, and 4.943 +- 0.005 A. The compounds appear golden yellow with a metallic luster. From chemical analyses and cell parameter consideration it is concluded that these compounds are the rare earth monoxides. For Ln = Gd, Dy, Tm, no reaction is observed at 50 kbar and 10000C. The rare earth monoxides show a variety of properties: LaO, CeO, PrO, and NdO are metallic with the rare earth in the trivalent state; EuO and YbO are semiconductors with the rare earth in the divalent state; SmO is metallic with samarium in an intermediate valence state close to 3.

1981-01-01

195

Numerical Results of Earth's Core Accumulation 3-D Modelling  

Science.gov (United States)

For a long time as a most convenient had been the model of mega impact in which the early forming of the Earth's core and mantle had been the consequence of formed protoplanet collision with the body of Mercurial mass. But all dynamical models of the Earth's accumulation and the estimations after the Pb-Pb system, lead to the conclusion that the duration of the planet accumulation was about 1 milliard years. But isotopic results after the W-Hf system testify about a very early (5-10) million years, dividing of the geochemical reservoirs of the core and mantle. In [1,3] it is shown, that the account of energy dissipating by the decay of short living radioactive elements and first of all Al,it is sufficient for heating even small bodies with dimensions about (50-100) km up to the iron melting temperature and can be realized a principal new differentiation mechanism. The inner parts of the melted preplanets can join and they are mainly of iron content, but the cold silicate fragments return to the supply zone. Only after the increasing of the gravitational radius, the growing area of the future core can save also the silicate envelope fragments. All existing dynamical accumulation models are constructed by using a spherical-symmetrical model. Hence for understanding the further planet evolution it is significant to trace the origin and evolution of heterogeneities, which occur on the planet accumulation stage. In that paper we are modeling distributions of temperature, pressure, velocity of matter flowing in a block of 3D- spherical body with a growing radius. The boundary problem is solved by the finite-difference method for the system of equations, which include equations which describe the process of accumulation, the Safronov equation, the equation of impulse balance, equation Navier-Stocks, equation for above litho static pressure and heat conductivity in velocity-pressure variables using the Businesque approach. The numerical algorithm of the problem solution in velocity-pressure variables is constructed on the base of the splitting method. The velocity field and pressure field we obtain using the checkerboard grid. The occurring and evolution of the initial heterogeneities in the growing planets is caused by heterogeneous distribution of falling accumulated bodies. 1.V.N. Anfilogov and Yu.V.Khachai A Possible Scenario of Material Differentiation at the Ini-tial Stage of the Earth's Formation // Doklady Earth Sciences. V. 403 A.N 6. 2005. 954-957 Transl. from Doklady Akademii Nauk.v.403.N 6.2005.803-806. 2.Khachay Yu., Anfilogov V. VARIANTS OF TEMPERATURE DISTRIBUTIONS IN THE EARTH ON ITS ACCUMULATION // Proc. of the 6th Orlov Conf. "The study of the Earth as a planet by methods of geophysics, geodesy and astronomy" K.: Akad. 2010.197-202. 3.V.N. Anfilogov and Yu.V.Khachay Differentiation of the mantle matter during the process of the Earth's accumulation and early crust formation // Litosphere, 2012, N6, 3-15.

Khachay, Yurie; Anfilogov, Vsevolod

2013-04-01

196

Social Balance Theory  

CERN Document Server

We construct a model based on social balance theory proposed by Fritz Heider to analyze the interpersonal network among social agents. The model of social balance theory provides us an interesting tool to see how a social group evolves to the possible balance state. We introduce the balance index that can be used to measure social balance in macro structure level (global balance index) or in micro structure (local balance index) to see how the local balance index influences the global balance structure. Several experiments are done and we discover how the social group can form separation of subgroups in a group or strengthening a social group while emphasizing the structure theorem and social mitosis previously introduced.

Khanafiah, D; Khanafiah, Deni; Situngkir, Hokky

2004-01-01

197

Earth-Sun Geometry - Earth Revolution Animation  

Science.gov (United States)

The representation is an animation of the Earth revolving around the sun. The Earth is shown as a solid green sphere with the equator and arctic circle marked with black lines and the dark side of the Earth shaded. The Earth's axis is shown with a red line. As the Earth revolves around the sun, the axis is shown to always be pointing in the same direction. The positions of Earth at the winter solstice, vernal equinox, summer solstice, and autumnal equinox are labeled.

Pidwirny, Michael; Okanagan, Scott J.

198

On linear balancing sets  

CERN Multimedia

Let n be an even positive integer and F be the field GF(2). A word in F is called balanced if its Hamming weight is n/2. A subset C \\subseteq F^n is called a balancing set if for every word y \\in F^n there is a word x \\in C such that y+x is balanced. It is shown that most linear subspaces of F^n of dimension slightly larger than (3/2) \\log_2(n) are balancing sets. An application of linear balancing sets is presented for designing efficient error-correcting coding schemes in which the codewords are balanced.

Mazumdar, Arya; Vontobel, Pascal O

2009-01-01

199

Earth System History  

Science.gov (United States)

... Earth System History - (ESH) Synopsis of Program: The goals of the Earth System History (ESH ... s paleoenvironmental system. In this context, the term "Earth system" refers to elements of the ...

200

Random walk and balancing  

CERN Multimedia

Presents a minireview of topics concerned with balancing in quiet (bipedal) standing, and balancing of a stick. In the focus is the apparent stochastic nature of the swaying of the human inverted pendulum.

Borg, F G

2004-01-01

 
 
 
 
201

Strength and Balance Exercises  

Science.gov (United States)

... Stand behind a straight-backed chair, with both hands on the back of the chair for balance. Place ... Stand behind a straight-backed chair, with both hands on the back of the chair for balance. Place ...

202

Pan Balance - Numbers  

Science.gov (United States)

Use this tool to find numerical expressions that are equivalent to one another. If equivalent expressions are placed in the blue and red pans, the scale will balance and the equation will show in the table next to the balance.

Mathematics, National C.

2009-07-22

203

Free oscillation of the Earth  

Directory of Open Access Journals (Sweden)

Full Text Available   This work is a study of the Earths free oscillations considering a merge of solid and liquid model. At the turn of 19th century Geophysicists presented the theory of the free oscillations for a self-gravitating, isotropic and compressible sphere. Assuming a steel structure for an Earth size sphere, they predicted a period of oscillation of about 1 hour. About 50 years later, the free oscillations of stars was studied by Cowling and others. They classified the oscillation modes of the stars into acoustic and gravity modes on the basis of their driving forces. These are pressure and buoyancy forces respectively. The earliest measurements for the period of the free oscillations of the Earth was made by Benyove from a study of Kamchathca earthquake. Since then, the Geophysicists have been trying to provide a theoretical basis for these measurements. Recently, the theory concerning oscillations of celestial fluids is extended by Sobouti to include the possible oscillations of the Earthlike bodies. Using the same technique, we study the free oscillations of a spherically symmetric, non-rotating and elastic model for the Earth.   We used the actual data of the Earths interior structure in our numerical calculations. Numerical results show that there exist three distinct oscillation modes namely acoustic, gravity and toroidal modes. These modes are driven by pressure, buoyancy and shear forces respectively. The shear force is due to the elastic properties of the solid part of the Earth. Our numerical results are consistent with the seismic data recorded from earthquake measurements.

Y. Abedini

2000-01-01

204

Balance and flux  

Science.gov (United States)

Ecosystems and populations of organisms within ecosystems function by the principle of balance and flux. Balance can be thought of as a state of equilibrium, or a state of equal changes between two sides. Flux can be thought of as a rate of flow or changes. Even small changes in an ecosystem's or population's balance and flux could lead to disaster.

Olivia Worland (Purdue University;Biological Sciences)

2008-06-16

205

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

UK PubMed Central (United Kingdom)

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.

Lackner JR; Graybiel A

1984-03-01

206

Near-earth Thin Current Sheets and Birkeland Currents during Substorm Growth Phase  

International Nuclear Information System (INIS)

[en] Two important phenomena observed during the magnetospheric substorm growth phase are modeled: the formation of a near-Earth (|X| ? 9 RE) thin cross-tail current sheet, as well as the equatorward shift of the ionospheric Birkeland currents. Our study is performed by solving the 3-D force-balance equation with realistic boundary conditions and pressure distributions. The results show a cross-tail current sheet with large current (J? ? 10 nA/m2) and very high plasma ? (? ? 40) between 7 and 10 RE. The obtained region-1 and region-2 Birkeland currents, formed on closed field lines due to pressure gradients, move equatorward and become more intense (Jparallel max ? 3 (micro)A/m2) compared to quiet times. Both results are in agreement with substorm growth phase observations. Our results also predict that the cross-tail current sheet maps into the ionosphere in the transition region between the region-1 and region-2 currents

2003-01-01

207

Volatile accretion history of the Earth.  

UK PubMed Central (United Kingdom)

It has long been thought that the Earth had a protracted and complex history of volatile accretion and loss. Albarède paints a different picture, proposing that the Earth first formed as a dry planet which, like the Moon, was devoid of volatile constituents. He suggests that the Earth's complement of volatile elements was only established later, by the addition of a small veneer of volatile-rich material at ?100 Myr (here and elsewhere, ages are relative to the origin of the Solar System). Here we argue that the Earth's mass balance of moderately volatile elements is inconsistent with Albarède's hypothesis but is well explained by the standard model of accretion from partially volatile-depleted material, accompanied by core formation.

Wood BJ; Halliday AN; Rehkämper M

2010-10-01

208

DYMAC digital electronic balance  

International Nuclear Information System (INIS)

[en] The Dynamic Materials Accountability (DYMAC) System at LASL integrates nondestructive assay (NDA) instruments with interactive data-processing equipment to provide near-real-time accountability of the nuclear material in the LASL Plutonium Processing Facility. The most widely used NDA instrument in the system is the DYMAC digital electronic balance. The DYMAC balance is a commercial instrument that has been modified at LASL for weighing material in gloveboxes and for transmitting the weight data directly to a central computer. This manual describes the balance components, details the LASL modifications, reviews a DYMAC measurement control program that monitors balance performance, and provides instructions for balance operation and maintenance

1980-01-01

209

Performance of balanced bellows safety relief valves  

International Nuclear Information System (INIS)

By the nature of its design, the set point and lift of a conventional spring loaded safety relief valve are sensitive to back pressure. One way to reduce the adverse effects of the back pressure on the safety relief valve function is to install a balanced bellows in a safety relief valve. The metallic bellows has a rather wide range of manufacturing tolerance which makes the design of the bellows safety relief valve very complicated. The state-of-the-art balanced bellows safety relief valve can only substantially minimize, but cannot totally eliminate the back pressure effects on its set point and relieving capacity. Set point change is a linear function of the back pressure to the set pressure ratio. Depending on the valve design, the set point correction factor can be either greater or smaller than unity. There exists an allowable back pressure and critical back pressure for each safety relief valve. When total back pressure exceeds the Ra, the relieving capacity will be reduced mainly resulting from the valve lift being reduced by the back pressure and the capacity reduction factor should be applied in valve sizing. Once the Rc is exceeded, the safety relief valve becomes unstable and loses its over pressure protection capability. The capacity reduction factor is a function of system overpressure, but their relationship is non-linear in nature. (orig.).

1992-06-05

210

Earth drilling apparatus and method  

Energy Technology Data Exchange (ETDEWEB)

Earth well drilling apparatus including piping in a well, a metal drilling tube within the piping, and a hydraulic jet drilling head secured to the lower end of the tube. A seal is disposed between the piping and the tube. The drilling head is urged downwardly through the piping under hydraulic pressure through a tube bending assembly laterally extensible from a retracted position substantially within the structure. The hydraulic pressure propels the tube downwardly through the piping and bending assembly to bend the tube and to direct the drilling head laterally toward the formation.

Dickinson III, B. W. O.; Dickinson, R. W.; McGhee, J.; Odgers, I. L.

1985-02-05

211

Why Earth Science?  

Science.gov (United States)

This article briefly describes Earth science. The study of Earth science provides the foundation for an understanding of the Earth, its processes, its resources, and its environment. Earth science is the study of the planet in its entirety, how its lithosphere, atmosphere, hydrosphere, and biosphere work together as systems and how they affect…

Smith, Michael J.

2004-01-01

212

Functional balance tests  

Directory of Open Access Journals (Sweden)

Full Text Available Background and Aim: All activities of daily living need to balance control in static and dynamic movements. In recent years, a numerous increase can be seen in the functional balance assessment tools. Functional balance tests emphasize on static and dynamic balance, balance in weight transfer, the equilibrium response to the imbalances, and functional mobility. These standardized and available tests assess performance and require minimal or no equipment and short time to run. Functional balance is prerequisite for the most static and dynamic activities in daily life and needs sufficient interaction between sensory and motor systems. According to the critical role of balance in everyday life, and wide application of functional balance tests in the diagnosis and assessment of patients, a review of the functional balance tests was performed.Methods: The Google Scholar, PubMed, Science Direct, Scopus, Magiran, Iran Medex, and IranDoc databases were reviewed and the reliable and valid tests which were mostly used by Iranian researchers were assessed.Conclusion: It seems that Berg balance scale (BBS) have been studied by Iranian and foreign researches more than the other tests. This test has high reliability and validity in elderly and in the most neurological disorders.

Parvin Raji

2012-01-01

213

Earth Global Reference Atmospheric Model 2007 (Earth-GRAM07)  

Science.gov (United States)

Engineering models of the atmosphere are used extensively by the aerospace community for design issues related to vehicle ascent and descent. The Earth Global Reference Atmosphere Model version 2007 (Earth-GRAM07) is the latest in this series and includes a number of new features. Like previous versions, Earth-GRAM07 provides both mean values and perturbations for density, temperature, pressure, and winds, as well as monthlyand geographically-varying trace constituent concentrations. From 0 km to 27 km, thermodynamics and winds are based on the National Oceanic and Atmospheric Administration Global Upper Air Climatic Atlas (GUACA) climatology. For altitudes between 20 km and 120 km, the model uses data from the Middle Atmosphere Program (MAP). Above 120 km, Earth-GRAM07 now provides users with a choice of three thermosphere models: the Marshall Engineering Thermosphere (MET-2007) model; the Jacchia-Bowman 2006 thermosphere model (JB2006); and the Naval Research Labs Mass Spectrometer, Incoherent Scatter Radar Extended Model (NRL MSIS E-00) with the associated Harmonic Wind Model (HWM-93). In place of the GUACA and MAP datasets, Earth-GRAM07 has the option of using the new 2006 revised Range Reference Atmosphere (RRA) data, the earlier (1983) RRA data, or the user may provide their own data as an auxiliary profile. Refinements of the perturbation model are also discussed which produce wind shears more similar to those observed at the Kennedy Space Center than the previous version Earth-GRAM99. In addition, the dispersions are more normally distributed, especially at the extremes.

Leslie, Fred

214

The Influence of the Atmospheric Transmission for the Solar Radiation and Earth’s Surface Radiation on the Earth’s Climate  

Directory of Open Access Journals (Sweden)

Full Text Available The physical and mathematical model of the planetary heat balance is developed to establish the influence of the atmospheric transmission for the solar radiation in the shortwave spectrum range and for the surface IR radiation in the longwave spectrum range on the Earth’s climate. It is shown the possibility of the decreas- ing of the atmospheric and surface temperatures with the decreasing of the atmospheric transmission for IR spectrum range, and this decreasing can’t be equilibrated with the change of the atmospheric transmission for the incoming solar radiation.

Habibullo I. Abdussamatov; Alexander I. Bogoyavlenskii; Sergey I. Khankov; Yevgeniy V. Lapovok

2010-01-01

215

A hydrogen-rich early Earth atmosphere.  

UK PubMed Central (United Kingdom)

We show that the escape of hydrogen from early Earth's atmosphere likely occurred at rates slower by two orders of magnitude than previously thought. The balance between slow hydrogen escape and volcanic outgassing could have maintained a hydrogen mixing ratio of more than 30%. The production of prebiotic organic compounds in such an atmosphere would have been more efficient than either exogenous delivery or synthesis in hydrothermal systems. The organic soup in the oceans and ponds on early Earth would have been a more favorable place for the origin of life than previously thought.

Tian F; Toon OB; Pavlov AA; De Sterck H

2005-05-01

216

A hydrogen-rich early Earth atmosphere.  

Science.gov (United States)

We show that the escape of hydrogen from early Earth's atmosphere likely occurred at rates slower by two orders of magnitude than previously thought. The balance between slow hydrogen escape and volcanic outgassing could have maintained a hydrogen mixing ratio of more than 30%. The production of prebiotic organic compounds in such an atmosphere would have been more efficient than either exogenous delivery or synthesis in hydrothermal systems. The organic soup in the oceans and ponds on early Earth would have been a more favorable place for the origin of life than previously thought. PMID:15817816

Tian, Feng; Toon, Owen B; Pavlov, Alexander A; De Sterck, H

2005-04-07

217

Technique for enhanced rare earth separation  

UK PubMed Central (United Kingdom)

A process is demonstrated for the efficient separation of rare earth elements, using a combination of selective reduction and vacuum distillation of halides. The large differences in the redox chemistry of the rare earth elements and in the vapor pressures of rare earth di- and trihalides are exploited for separation. Experimental proof of concept is provided for the binary systems praseodymium-neodymium and neodymium-samarium. This process enhances the separation factor for the isolation of samarium and neodymium from their mixture by more than an order of magnitude.

Uda T; Jacob KT; Hirasawa M

2000-09-01

218

Preseason and midseason balance ability of professional Australian footballers.  

UK PubMed Central (United Kingdom)

Balance ability has been shown to be important for sports performance and injury prevention. It is unclear whether balance ability changes due to sports participation and regular training without specific balance training. It has not been shown whether certain sports such as the various football codes that often involve single limb stance and balance as part of kicking, running, rapid changes of direction, jumping, and landing actually influence balance ability. The aim of this study was to determine whether there was a difference in balance ability measured at preseason and during the competitive season for elite footballer. Twenty-eight professional Australian footballers who did not undertake any specific balance training took part in this study. Postural sway from single limb balance on a force platform was measured for both limbs 1 week before the start and midway through a 22-week competitive season. The subjects were required to step onto a balance mat on top of the force platform and maintain balance for 20 seconds. The maximum sway of the center of pressure in the mediolateral direction was used as the balance score. It was found that there was not a significant difference in the balance ability measurement at the start and during the competitive season. Sports participation and regular training did not influence balance ability in this cohort of athletes.

Hrysomallis C

2008-01-01

219

Thermophysical properties of liquid rare earth metals  

Science.gov (United States)

The thermodynamical properties like long wavelength limit S(0), iso-thermal compressibility (?T), thermal expansion coefficient (?V), thermal pressure coefficient (?V), specific heat at constant volume (CV) and specific heat at constant pressure (CP) are calculated for liquid rare earth metals. Our newly constructed parameter free model potential is used to describe the electron ion interaction due to Sarkar et al (S) local field correction function. Lastly, we conclude that our newly constructed model potential is capable to explain the thermophysical properties of liquid rare earth metals.

Thakor, P. B.; Sonvane, Y. A.; Patel, H. P.; Jani, A. R.

2013-06-01

220

Judicial Checks and Balances  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the Anglo?American constitutional tradition, judicial checks and balances are often seen as crucial guarantees of freedom. Hayek distinguishes two ways in which the judiciary provides such checks and balances: judicial independence and constitutional review. We create a new database of constituti...

La Porta, Rafael; Lopez-de-Silanes, Florencio; Pop-Eleches, Cristian; Shleifer, Andrei

 
 
 
 
221

Judicial Checks and Balances  

Science.gov (United States)

In the Anglo-American constitutional tradition, judicial checks and balances are often seen as crucial guarantees of freedom. Hayek distinguishes two ways in which the judiciary provides such checks and balances: judicial independence and constitutional review. We create a new database of constitutional rules in 71 countries that reflect these…

La Porta, Rafael; Lopez-de-Silanes, Florencio; Pop-Eleches, Cristian; Shleifer, Andrei

2004-01-01

222

Balanced fractional opial inequalities  

International Nuclear Information System (INIS)

Here we present Lp, p>1, fractional Opial type inequalities subject to high order boundary conditions. They involve the right and left Caputo, Riemann-Liouville fractional derivatives. These derivatives are blended together into the balanced Caputo, Riemann-Liouville, respectively, fractional derivative. This balanced fractional derivative is introduced here for the first time. We give applications to a special case.

2009-11-15

223

Balanced fractional opial inequalities  

Energy Technology Data Exchange (ETDEWEB)

Here we present L{sub p}, p>1, fractional Opial type inequalities subject to high order boundary conditions. They involve the right and left Caputo, Riemann-Liouville fractional derivatives. These derivatives are blended together into the balanced Caputo, Riemann-Liouville, respectively, fractional derivative. This balanced fractional derivative is introduced here for the first time. We give applications to a special case.

Anastassiou, George A. [Department of Mathematical Sciences, University of Memphis, Memphis, TN 38152 (United States)], E-mail: ganastss@gmail.com

2009-11-15

224

Pan Balance - Shapes  

Science.gov (United States)

This resource provides a virtual manipulative pan balance to explore and practice equality with geometric shapes. Each shape is assigned a certain weight. The pictorial representation is entered in a table and the items on each side of the balance can be represented by an algebraic expression.

Mathematics, Illuminations N.

2009-03-04

225

Journal of Earth Science ???????????  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Journal of Earth Science, issued bimonthly through China University of Geosciences, covers all branches of geology and related technology in the exploration and utilization of earth resources. Founded in 1990 as the Journal of Ch...

226

Earth and Moon Viewer  

Science.gov (United States)

This site allows users to view the earth and moon, and daylight and night regions, from a wide range of viewpoints. These include from the sun, the moon, the earth, at any point above the earth. Cloud and weather information is also provided from satellite images.

Walker, John

2004-02-16

227

Sun-Earth Viewer  

Science.gov (United States)

The Sun-Earth Viewer is an experimental Flash-based viewer that allows visitors to zoom and pan live NASA solar and Earth images. In addition, it features video interviews with scientists and detailed scientific animations, extensive interactive sun-earth illustrations, and live interactive solar and aurora images.

228

Models of Earth  

Science.gov (United States)

In this activity, candy models are used to demonstrate the features of the Earth, including its internal structure and layers. Students learn why models are essential in Earth science and answer questions about how their candy models do and do not compare with the actual Earth.

Ladue, Nicole

229

The fate of Earth’s ocean  

Directory of Open Access Journals (Sweden)

Full Text Available Questions of how water arrived on the Earth’s surface, how much water is contained in the Earth system as a whole, and how much water will be available in the future in the surface reservoirs are of central importance to our understanding of the Earth. To answer the question about the fate of the Earth’s ocean, one has to study the global water cycle under conditions of internal and external forcing processes. Modern estimates suggest that the transport of water to the surface is five times smaller than water movement to the mantle, so that the Earth will lose all its sea-water in one billion years from now. This straightforward extrapolation of subduction-zone fluxes into the future seems doubtful. Using a geophysical modelling approach it was found that only 27% of the modern ocean will be subducted in one billion years. Internal feedbacks will not be the cause of the ocean drying out. Instead, the drying up of surface reservoirs in the future will be due to the increase in temperature caused by a maturing Sun connected to hydrogen escape to outer space. Keywords: Surface water reservoir, water fluxes, regassing, degassing, global water cycle

C. Bounama; S. Franck; W. von Bloh

2001-01-01

230

The Balance Evaluation Systems Test (BESTest) to Differentiate Balance Deficits  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Background: Current clinical balance assessment tools do not aim to help therapists identify the underlying postural control systems responsible for poor functional balance. By identifying the disordered systems underlying balance control, therapists can direct specific types of intervention for dif...

Horak, Fay B; Wrisley, Diane M; Frank, James

231

How back pressure affects safety relief valves  

Energy Technology Data Exchange (ETDEWEB)

The prefered valve types to reduce back pressure are the pilot operated valve, the balanced direct spring valve, and the conventional direct spring valve. Back pressure (static pressure at the outlet when the valve is closed), superimposed back pressure, and built up back pressure are defined. The relief characteristics of the pilot, balanced, and direct spring valves are schematicized. Typical safety valve operations are outlined. Methods for sizing discharge piping to avoid piping pressure losses that produce excessive back pressure are recommended. The guidelines discussed improve overpressure protection.

Papa, D.M.

1983-05-01

232

BIOCHEMISTRY: Balancing Cellular Energy  

Science.gov (United States)

Access to the article is free, however registration and sign-in are required. The structure of the core of an enzyme complex that senses and responds to changes in the cell's energy balance has been solved. Adenosine monophosphate-activated protein kinase (AMPK) complex regulates cellular energy balance. On page 1726 of this issue, Townley and Shapiro (2) describe crystal structures for the core of the AMPK complex from fission yeast. The study provides insights into binding of AMP and adenosine triphosphate (ATP), which may be very helpful in the design of new drugs that might treat disorders of energy balance (i.e. obesity and type-2 diabetes).

D. Grahame Hardie (University of Dundee;Division of Molecular Physiology)

2007-03-23

233

Older Adults and Balance Problems  

Medline Plus

Full Text Available ... to maintain balance with the help of our vestibular system, which is located in the inner ear. ... nerve fibers collect and join to form the vestibular, or balance, nerves. The balance nerve then sends ...

234

National Energy Balance - 1976.  

Science.gov (United States)

Based on available data from IBGE, CNP/Petrobras, Eletrobras, Nuclebras and other governmental enterprises the National Energy Balance was done. This publication covers since 1965 to 1975. In conformity to the international rules, the energy resources use...

1976-01-01

235

National Energy Balance - 1984  

International Nuclear Information System (INIS)

The National Energy Balance - 1984 shows energy fluxes of several primary and secondary energy sources, since the productions to final consumption in the main economic sectors, since 1973 to 1983. (E.G.).

236

National Energy Balance - 1985  

International Nuclear Information System (INIS)

The National Energy Balance - 1985 shows energy fluxes of several primary and secondary energy sources, since the production to the final consumption in the main economic sectors, since 1974 to 1984 (E.G.).

1985-01-01

237

Fluid and Electrolyte Balance  

Science.gov (United States)

... They are in your blood, urine and body fluids. Maintaining the right balance of electrolytes helps your ... them from the foods you eat and the fluids you drink. Levels of electrolytes in your body ...

238

National Energy Balance-1987  

International Nuclear Information System (INIS)

The National Energy Balance - 1987 showns energy fluxes of several primary and secondary energy sources, since the production to final consumption in the main economic sectors, since 1971 to 1986. (E.G.).

239

A Balanced Marine Aquarium.  

Science.gov (United States)

A balanced marine aquarium reproduces the natural environment as closely as possible, and permits the successful mixing of fish and invertebrates within the closed system which has become increasingly popular in the past few years. It is more appealing an...

B. J. Palko

1981-01-01

240

Workhours and worklife balance  

Directory of Open Access Journals (Sweden)

Full Text Available OBJECTIVES: The purpose of the present review was to summarize the scientific literature about the consequences of long and nonstandard workhours and employee influence over workhours on different measures of worklife balance. METHODS: Literature with a focus on the social consequences of the organization of workhours on worklife balance was searched in large databases such as PSYC-info and PubMed; the result was supplemented with other relevant literature. RESULTS: An association between larger numbers of workhours and lower levels of worklife balance was strongly supported among women. For men, the results were less conclusive, while, for gender-mixed groups, an association between overtime work and lower levels of worklife balance was strongly supported. There was strong evidence that nonstandard workhours had a negative influence on worklife balance and some evidence that it had a negative influence on children’s well-being and on marital satisfaction. Employee influence over work schedule was associated with a better worklife balance in several studies. However, clear conclusions were difficult to draw due to methodological problems in the studies. Interventions that included reduced hours with wage compensation, rapidly rotating shifts, and increased influence on work schedules all showed positive effects on social life indicators. CONCLUSIONS: The social consequences of worktime arrangements are relatively well documented in the scientific literature. There is a need for intervention studies, longitudinal studies, and studies focusing on the influence on schedule, consequences regarding children’s development and well-being, and marital satisfaction.

Karen Albertsen; Guðbjörg Linda Rafnsdóttir; Asbjörn Grimsmo; Kristinn Tómasson; Kaisa Kauppinen

2008-01-01

 
 
 
 
241

Distribution of neutrons near the Earth’s surface  

Directory of Open Access Journals (Sweden)

Full Text Available The distribution of the count rate of neutrons (per second) near the Earth’s surface for two directions: towards the Earth and away from it, is studied using the experimental data, obtained in Moscow during 1996. The analysis shows that the mathematical approximation of the neutron count rate distribution can be described by a sum of two functions: a Poison distribution and a log-normal distribution. This is in agreement with the two known sources of the total neutron flux near the Earth’s surface: generation of neutrons in nuclear interactions of high-energy cosmic ray particles with the Earth’s atmosphere and neutron production in the Earth’s crust. The log-normal distribution describes the contribution of the Earth’s crust to the total neutron flux near the Earth. Therefore, these dynamic processes in the Earth’s crust change the parameters of the log-normal distribution.

B. M. Kuzhevskij; O. Yu. Nechaev; E. A. Sigaeva

2003-01-01

242

Clouds and the Earth's Radiant Energy System  

Science.gov (United States)

The Clouds and the Earth's Radiant Energy System (CERES) instrument is one of five instruments that will be flown aboard the Tropical Rainfall Measuring Mission (TRMM) observatory. Data from the CERES instrument will be used to study the energy exchanged between the Sun and the Earth's atmosphere, surface and clouds, and space. This webpage describes the TRMM mission, the CERES insrument, and how Earth's daily weather and climate are controlled by the balance between the amount of solar energy received by the Earth (both by its surface and its atmosphere and clouds) and the amount of energy emitted by Earth into space. School children worldwide will be involved in the CERES program, enabling them to be part of a scientific project. As a CERES instrument passes over, students will make local observations to determine the types of clouds over their school, the clouds' altitudes and how much of the sky they cover. Via the Internet, the students will then place their data in the NASA Langley Distributed Active Archive Center where the data will be stored for further analysis by the CERES science team.

243

On the Misdiagnosis of Surface Temperature Feedbacks from Variations in Earth’s Radiant Energy Balance  

Directory of Open Access Journals (Sweden)

Full Text Available The sensitivity of the climate system to an imposed radiative imbalance remains the largest source of uncertainty in projections of future anthropogenic climate change. Here we present further evidence that this uncertainty from an observational perspective is largely due to the masking of the radiative feedback signal by internal radiative forcing, probably due to natural cloud variations. That these internal radiative forcings exist and likely corrupt feedback diagnosis is demonstrated with lag regression analysis of satellite and coupled climate model data, interpreted with a simple forcing-feedback model. While the satellite-based metrics for the period 2000–2010 depart substantially in the direction of lower climate sensitivity from those similarly computed from coupled climate models, we find that, with traditional methods, it is not possible to accurately quantify this discrepancy in terms of the feedbacks which determine climate sensitivity. It is concluded that atmospheric feedback diagnosis of the climate system remains an unsolved problem, due primarily to the inability to distinguish between radiative forcing and radiative feedback in satellite radiative budget observations.

Roy W. Spencer; William D. Braswell

2011-01-01

244

EarthExplorer  

Science.gov (United States)

The EarthExplorer trifold provides basic information for on-line access to remotely-sensed data from the U.S. Geological Survey Earth Resources Observation and Science (EROS) Center archive. The EarthExplorer (http://earthexplorer.usgs.gov/) client/server interface allows users to search and download aerial photography, satellite data, elevation data, land-cover products, and digitized maps. Minimum computer system requirements and customer service contact information also are included in the brochure.

Houska, Treva

2012-01-01

245

Momentum balance and flux conservation in model magnetospheric magnetic fields  

International Nuclear Information System (INIS)

[en] We have tested four recent quantitative magnetospheric magnetic field models to determine whether the magnetic field configuration is consistent with a balance of forces between the J x B force and the gradient of the pressure. A necessary condition for the models to be consistent with an isotropic pressure distribution is that curl (J x B) vanish. None of the models (Olson-Pfitzer, Tsyganenko, Hedgecock-Thomas, and Beard) meet this requirement: Our analysis indicates that the models are intrinsically inconsistent with momentum balance with any isotropic pressure distribution. We have also, for purposes of comparison, examined delxB. In certain models this can be nonzero

1982-09-01

246

Momentum balance and flux conservation in model magnetospheric magnetic fields  

Energy Technology Data Exchange (ETDEWEB)

We have tested four recent quantitative magnetospheric magnetic field models to determine whether the magnetic field configuration is consistent with a balance of forces between the J x B force and the gradient of the pressure. A necessary condition for the models to be consistent with an isotropic pressure distribution is that curl (J x B) vanish. None of the models (Olson-Pfitzer, Tsyganenko, Hedgecock-Thomas, and Beard) meet this requirement: Our analysis indicates that the models are intrinsically inconsistent with momentum balance with any isotropic pressure distribution. We have also, for purposes of comparison, examined delxB. In certain models this can be nonzero.

Walker, R.J.; Southwood, D.J.

1982-09-01

247

Capturing Near Earth Objects  

CERN Multimedia

Recently, Near Earth Objects (NEOs) have been attracting great attention, and thousands of NEOs have been found to date. This paper examines the NEOs' orbital dynamics using the framework of an accurate solar system model and a Sun-Earth-NEO three-body system when the NEOs are close to Earth to search for NEOs with low-energy orbits. It is possible for such an NEO to be temporarily captured by Earth; its orbit would thereby be changed and it would become an Earth-orbiting object after a small increase in its velocity. From the point of view of the Sun-Earth-NEO restricted three-body system, it is possible for an NEO whose Jacobian constant is slightly lower than C1 and higher than C3 to be temporarily captured by Earth. When such an NEO approaches Earth, it is possible to change its orbit energy to close up the zero velocity surface of the three-body system at point L1 and make the NEO become a small satellite of the Earth. Some such NEOs were found; the best example only required a 410m/s increase in velocit...

Baoyin, Hexi; Li, Junfeng; 10.1088/1674-4527/10/6/008

2011-01-01

248

Geomagnetic field of earth  

International Nuclear Information System (INIS)

[en] In this paper is introduced the theory of geomagnetic field of the Earth. A homogenous and isotropic sphere is taken for a model of Earth with a bar magnet at its center as a magnetic potential. The understanding of the real origin of geomagnetic field produced from differential rotation of inner core with respect to the outer core of Earth is here presented. Special attention is given to the latest observed data of the established net of geomagnetic repeat stations in the Republic of Macedonia. Finally, the maps of elements of geomagnetic field and the equation for calculation of normal magnetic field of Earth are provided. (Author)

2008-01-01

249

The Earth: Present Scenario  

Directory of Open Access Journals (Sweden)

Full Text Available In this article, the present scenario of our motherly loved planet ‘Earth’ is presented. We are living in one of the most developed phases of the Earth’s life cycle. The choices we make today will determine the life on the Earth, tomorrow. Problems that are been created by us and the consequences we are going to face are discussed in length. Some statistical data is provided to get a brief idea. Measure/prevention(s) to combat the upcoming problems have been putforth.

Nishad Gopal Deshpande

2009-01-01

250

Magnetospheric plasma pressures in the midnight meridian: Observations from 2. 5 to 35 R sub E  

Energy Technology Data Exchange (ETDEWEB)

Plasma pressure data from the ISEE 2 fast plasma experiment (FPE) were statistically analyzed to determine the plasma sheet pressure versus distance in the midnight local time sector of the near-earth (12-35 R{sub E}) magnetotail plasma sheet. The observed plasma pressure, assumed isotropic, was mapped along model magnetic field flux tubes (obtained from the Tsyganenko and Usmanov (1982) model) to the magnetic equator, sorted according to magnetic activity, and binned according to the mapped equatorial location. In regions (L {approx gt} 12 R{sub E}) where the bulk of the plasma pressure was contributed by particles in the energy range of the FPE (70 eV to 40 keV for ions), the statistically determined peak plasma pressures vary with distance similarly to previously determined lobe magnetic pressures (i.e., in a time-averaged sense, pressure balance normal to the magnetotail magnetic equator in the midnight meridian is maintained between lobe magnetic and plasma sheet plasma pressures). Additional plasma pressure data obtained in the inner magnetosphere (2.5 < L < 7) by the Explorer 45, ATS 5, and AMPTE CCE spacecraft supplement the ISEE 2 data. Estimates of plasma pressures in the transition region (7-12 R{sub E}), where the magnetic field topology changes rapidly from a dipolar to a tail-like configuration, are compared with the observed pressure profiles. The quiet time transition region pressure estimates, obtained previously from inversions of empirical magnetic field models, bridge observations both interior to and exterior to the transition region in a reasonable manner. Quiet time observations and estimates are combined to provide profiles of the equatorial plasma pressure along the midnight meridian between 2.5 and 35 R{sub E}.

Spence, H.E.; Kivelson, M.G.; Walker, R.J. (Univ. of California, Los Angeles (USA)); McComas, D.J. (Los Alamos National Lab., NM (USA))

1989-05-01

251

Temperature response of Earth to the annual solar irradiance cycle  

International Nuclear Information System (INIS)

We directly determine the sensitivity and time delay of Earth's surface temperature response to annual solar irradiance variations from 60 years of data. A two-layer energy balance model is developed to interpret the results. Explaining both the resulting low sensitivity and time delay of 1-2 months requires negative feedback

2004-03-22

252

The ideal crystalloid - what is 'balanced'?  

UK PubMed Central (United Kingdom)

PURPOSE OF REVIEW: This review explores the contemporary definition of the term 'balanced crystalloid' and outlines optimal design features and their underlying rationale. RECENT FINDINGS: Crystalloid interstitial expansion is unavoidable, but also occurs with colloids when there is endothelial glycocalyx dysfunction. Reduced chloride exposure may lessen kidney dysfunction and injury with a possible mortality benefit. Exact balance from an acid-base perspective is achieved with a crystalloid strong ion difference of 24?mEq/l. This can be done simply by replacing 24?mEq/l of chloride in 0.9% sodium chloride with bicarbonate or organic anion bicarbonate substitutes. Potassium, calcium and magnesium additives are probably unnecessary. Large volumes of mildly hypotonic crystalloids such as lactated Ringer's solution reduce extracellular tonicity in volunteers and increase intracranial pressure in nonbrain-injured experimental animals. A total cation concentration of 154?mmol/l with accompanying anions provides isotonicity. Of the commercial crystalloids, Ringer's acetate solution is close to balanced from both acid-base and tonicity perspectives, and there is little current evidence of acetate toxicity in the context of volume loading, in contrast to renal replacement. SUMMARY: The case for balanced crystalloids is growing but unproven. A large randomized controlled trial of balanced crystalloids versus 0.9% sodium chloride is the next step.

Morgan TJ

2013-08-01

253

Multidimensional spectral load balancing  

Energy Technology Data Exchange (ETDEWEB)

We describe an algorithm for the static load balancing of scientific computations that generalizes and improves upon spectral bisection. Through a novel use of multiple eigenvectors, our new spectral algorithm can divide a computation into 4 or 8 pieces at once. These multidimensional spectral partitioning algorithms generate balanced partitions that have lower communication overhead and are less expensive to compute than those produced by spectral bisection. In addition, they automatically work to minimize message contention on a hypercube or mesh architecture. These spectral partitions are further improved by a multidimensional generalization of the Kernighan-Lin graph partitioning algorithm. Results on several computational grids are given and compared with other popular methods.

Hendrickson, B.; Leland, R.

1993-01-01

254

Getting the balance right  

International Nuclear Information System (INIS)

This 8 page leaflet is published by the Nuclear Electricity Information Group (NEIG) which is made up of eight different bodies working within the nuclear industry. It aims to present a balanced outline of the facts needed to form an opinion about energy policy in the UK. It looks at the price of electricity, other sources of electricity, (oil and coal, solar power, wind power, water power), safety in the nuclear industry, nuclear waste disposal and risks from radiation. The NEIG is in favour of a balanced energy programme with nuclear energy being only a part of the overall scheme. (U.K.).

1987-01-01

255

Assessment of the Hf-N, Zr-N and Ti-N phase diagrams at high pressures and temperatures: balancing between MN and M3N4 (M = Hf, Zr, Ti)  

International Nuclear Information System (INIS)

We study the nitrogen-rich part of the phase diagram Hf-N, Zr-N and Ti-N, employing first-principle calculations for an assessment of energy and enthalpy as a function of pressure. At zero pressure the novel cubic Th3P4-type structures are metastable modifications of M3N4 (M = Hf,Zr). The lowest energy configuration of both compounds is an orthorhombic Zr3N4-type. This orthorhombic structure will transform into the Th3P4-type at 9 and 6 GPa, for Hf3N4 and Zr3N4, respectively. The lowest energy configuration of Ti3N4 is a CaTi2O4-type structure. It will first transform into the orthorhombic Zr3N4-type at 3.8 GPa, then further transform into the cubic Th3P4-type at 15 GPa. The spinel type is metastable throughout the phase diagram for all three systems. The phase boundary between mononitrides MN and the M3N4-phases is accessed as a function of pressure. We include the entropy of gaseous nitrogen from tabulated data to estimate the free enthalpy ?G of the nitride phases. The orthorhombic modification of Hf3N4 turns out to be thermodynamically stable with respect to a decomposition into the mononitrides and nitrogen for temperatures up to about 1000 deg. C. The stability of Zr3N4 is in question; within the estimated error no final conclusion can be drawn. Ti3N4, on the other hand, will only be metastable. At higher pressures, however, the free energy of nitrogen is substantially reduced and the 3:4 compositions become more stable. We reproduce the experimental requirements (18 GPa and 2800 K) for the synthesis of the novel Hf3N4. At 2800 K the pressures needed to synthesize cubic phases of Zr3N4 and Ti3N4 are estimated to be 40 and 100 GPa, respectively.

2004-04-14

256

Assessment of the Hf N, Zr N and Ti N phase diagrams at high pressures and temperatures: balancing between MN and M3N4 (M = Hf, Zr, Ti)  

Science.gov (United States)

We study the nitrogen-rich part of the phase diagram Hf-N, Zr-N and Ti-N, employing first-principle calculations for an assessment of energy and enthalpy as a function of pressure. At zero pressure the novel cubic Th3P4-type structures are metastable modifications of M3N4 (M = Hf,Zr). The lowest energy configuration of both compounds is an orthorhombic Zr3N4-type. This orthorhombic structure will transform into the Th3P4-type at 9 and 6 GPa, for Hf3N4 and Zr3N4, respectively. The lowest energy configuration of Ti3N4 is a CaTi2O4-type structure. It will first transform into the orthorhombic Zr3N4-type at 3.8 GPa, then further transform into the cubic Th3P4-type at 15 GPa. The spinel type is metastable throughout the phase diagram for all three systems. The phase boundary between mononitrides MN and the M3N4-phases is accessed as a function of pressure. We include the entropy of gaseous nitrogen from tabulated data to estimate the free enthalpy DgrG of the nitride phases. The orthorhombic modification of Hf3N4 turns out to be thermodynamically stable with respect to a decomposition into the mononitrides and nitrogen for temperatures up to about 1000 °C. The stability of Zr3N4 is in question; within the estimated error no final conclusion can be drawn. Ti3N4, on the other hand, will only be metastable. At higher pressures, however, the free energy of nitrogen is substantially reduced and the 3:4 compositions become more stable. We reproduce the experimental requirements (18 GPa and 2800 K) for the synthesis of the novel Hf3N4. At 2800 K the pressures needed to synthesize cubic phases of Zr3N4 and Ti3N4 are estimated to be 40 and 100 GPa, respectively.

Kroll, Peter

2004-04-01

257

Investigating of relationship between balance parameters and balance lost of elite gymnastics on balance beam  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of this study was to investigate the relationship between balance lost on balance beam during the series performed by women gymnasts at International Bosphorus Gymnastics Tournament with anthropometric characteristics and static-dynamic balance test scores.19 female gymnasts (ages 14,53±2,20, training years9,0±3) participated in this research voluntarily. Before the competition, the static and dynamic balance score and anthropometrics values were taken by experienced researchers. In order to analyze balance loss on balance beam routines were evaluated by four international judges. The relationship between balance lost on balance beam and balance abilities were tested by “Pearson Correlation Analysis”.As a result although there were a negative relationship between dynamic balance parameters with age, training experience, some anthropometric features (p0,05). There were high negative relationship between final score and balance lost in balance beam series (p0,05).Artistic gymnastics training contribute positively to the improvement of balance skills, which may have enabled the gymnasts to preserve their balances perfectly, even under difficult circumstances. It can be summarized that the ability of the gymnasts in preserving their balances in similar degree, both during competition and during the tests given under laboratory conditions, can be an outcome of their improved balance skills acquired through exercise.

Ay?e Oya Erkut At?lgan; Manolya Ak?n; Ufuk Alpkaya; Salih P?nar

2012-01-01

258

Field dependence and body balance.  

UK PubMed Central (United Kingdom)

This study reports four points about the portable Rod and Frame Test performance of 30 Japanese women in terms of body balance. The primary findings using a stabilometer are: (a) field dependence correlated negatively with increased sway path within 1 min. both while a dot pattern as a visual stimulus was stationary and while it was moving. (b) Field dependence correlated positively with the difference in sway path between the two following phases, in one of which the subjects watched the horizontal visual movement to the right and in the other movement to the left. (c) Motion aftereffect had no direct and immediate influence on sway path, but rather a latent and long-term effect. And on a pedograph which measures the distribution of foot pressure and the shape of the sole, (d) field dependence correlated negatively with anterior positions of the center of foot pressure and with the proportion of the front part to the rear of the sole. Over-all, field dependence measured by the Rod and Frame Test seems to be associated with body posture when dot patterns are viewed.

Kitamura F; Matsunaga K

1990-12-01

259

NASA Visible Earth: Runoff  

Science.gov (United States)

The NASA Visible Earth site is a searchable collection of images of the Earth taken by orbiting satellites. This section features a variety of images specifically illustrating effects of runoff. Each image is available in one or more graphic formats and sizes, and is accompanied by a description, as well as detailed metadata about how the image was obtained.

260

The Earth Charter  

Science.gov (United States)

Humanity is part of a vast evolving universe. Earth is alive with a unique community of life. The forces of nature make existence a demanding and uncertain adventure, but Earth has provided the conditions essential to life's evolution. The resilience of the community of life and the well-being of humanity depend upon preserving a healthy biosphere…

Journal of Education for Sustainable Development, 2010

2010-01-01

 
 
 
 
261

The Earth Needs You!  

Science.gov (United States)

Celebrated annually on April 22, schools and communities organize numerous activities during Earth Day to promote awareness. To help teachers plan their own initiatives and to learn more about what is happening around the world, they can join the Earth Day Network at: http://network.earthday.net/. Once they have joined, they can create a webpage…

Curriculum Review, 2008

2008-01-01

262

Earth, Moon, and Planets ????????  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Earth, Moon, and Planets: An International Journal of Solar System Science, publishes original contributions on subjects ranging from star and planet formation and the origin and evolution of the solar and extra-solar planetary systems, to asteroids, comets, meteoroids and near-Earth objects,...

263

The Earth's Magnetic Field  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Earth's magnetic field is essential for life on Earth, as we know it, to exist. It forms a magnetic shield around the planet, protecting it from high energy particles and radiation from the Sun, which can cause damage to life, power systems, orbiting satellites, astronauts and spacecrafts. This ...

Edda Lína Gunnarsdóttir 1988

264

Earth Charter Initiative  

Science.gov (United States)

The Earth Charter is a declaration of fundamental principles for building a just, sustainable, and peaceful global society in the 21st century. The principles of the Earth Charter reflect extensive international consultations conducted over a period of many years. These principles are also based upon contemporary science, international law, and the insights of philosophy and religion.

2007-09-28

265

Work-life balance  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Many organisations today direct significant attention to creating a satisfying and motivating workplace and to this end implement a range of strategies including those which enable staff to achieve balance in their work and personal lives. AUT as a university has rigorously pursued this strategy and...

266

National Energy Balance - 1986  

International Nuclear Information System (INIS)

The National Energy Balance - 1986 shows energy fluxes of several primary and secondary energy sources, since the production to the final consumption in the main economic sectors, since 1970 to 1985. The incorporation of a new brazilian information is done. (E.G.).

1986-01-01

267

Multidimensional spectral load balancing  

Energy Technology Data Exchange (ETDEWEB)

A method of and apparatus for graph partitioning involving the use of a plurality of eigenvectors of the Laplacian matrix of the graph of the problem for which load balancing is desired. The invention is particularly useful for optimizing parallel computer processing of a problem and for minimizing total pathway lengths of integrated circuits in the design stage.

Hendrickson, Bruce A. (Albuquerque, NM); Leland, Robert W. (Albuquerque, NM)

1996-12-24

268

Work-Life Balance  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Finding the right balance between work and life is a subject many employees have difficulties with, because it's so hard to accomplish. Being satisfied with the combination of your work and life is not something that is easily reached. Many situations can lead to an unbalanced life, like for example...

Vlems, Elisa

269

1992 provisional energy balance  

International Nuclear Information System (INIS)

This paper gives a provisional energy balance in France in 1992. After a brief study of economical and energy context in world wide, this paper gives informations about energy dependence ratio and evolutions of energy sources (electric power, coal, petroleum, natural gas), evolution of energy consumption. 1 fig,. 4 tab

1993-01-01

270

Magnetospheric plasma pressures in the midnight meridian: Observations from 2.5 to 35 RE  

International Nuclear Information System (INIS)

[en] Plasma pressure data from the ISEE 2 fast plasma experiment (FPE) were statistically analyzed to determine the plasma sheet pressure versus distance in the midnight local time sector of the near-earth (12-35 RE) magnetotail plasma sheet. The observed plasma pressure, assumed isotropic, was mapped along model magnetic field flux tubes (obtained from the Tsyganenko and Usmanov (1982) model) to the magnetic equator, sorted according to magnetic activity, and binned according to the mapped equatorial location. In regions (L approx-gt 12 RE) where the bulk of the plasma pressure was contributed by particles in the energy range of the FPE (70 eV to 40 keV for ions), the statistically determined peak plasma pressures vary with distance similarly to previously determined lobe magnetic pressures (i.e., in a time-averaged sense, pressure balance normal to the magnetotail magnetic equator in the midnight meridian is maintained between lobe magnetic and plasma sheet plasma pressures). Additional plasma pressure data obtained in the inner magnetosphere (2.5 E), where the magnetic field topology changes rapidly from a dipolar to a tail-like configuration, are compared with the observed pressure profiles. The quiet time transition region pressure estimates, obtained previously from inversions of empirical magnetic field models, bridge observations both interior to and exterior to the transition region in a reasonable manner. Quiet time observations and estimates are combined to provide profiles of the equatorial plasma pressure along the midnight meridian between 2.5 and 35 RE

1989-05-01

271

The Moon and the Earth  

Science.gov (United States)

How does the moon affect the Earth? Read the information on the following websites to help you learn about the moon and the earth. Easy Moon/Earth info Easy Moon Info Moon Information Moon Photos Moon Phases ...

Benson, Carrie

2012-01-06

272

Rare earth industries: Upstream business  

International Nuclear Information System (INIS)

Evidently, many factors contribute to the rush to invest in the unprecedented revival of rare earths. One major reason has to do with the rapidly growing world demand. The other reason relates to the attractive price of rare earths which is projected to stay strong in the coming years. This is because supply is predicted to have difficulty keeping pace with demand. Experts believe a major driver of global rare earths demand is the forecasted expansion in the green economy. Climate change is a major driver of the green economy. With climate change, there is concern that the uncontrolled emission of the greenhouse gases, especially carbon dioxide, can lead to catastrophic consequences for the world. This has been documented in countless studies and reports. Another important driver of the green economy is the growing shortfall in many resources. The world is now experiencing declines in key resources to meet a growing global demand. With more than 6 billion people now in the world and growing, the pressure exerted on global resources including energy, water and food is a major concern. Recent demand surge in China and India has dented the supply position of major world resources. The much quoted Stern Report from the UK has warned that, unless immediate steps are taken to reduce greenhouse gas emissions, it may be a costly exercise to undertake the corrections later. Since energy use, especially fossil fuels, is a major contributor to climate change, greener options are being sought. Add to that the fact that the fossil energy resources of the world are declining, the need to seek alternatives becomes even more urgent. One option is to change to renewable energy sources. These include such potentials as solar, wind and biomass. Rare earths have somehow become a critical feature of the technologies in such renewable. Another option is to improve the efficient use of energy in transport, buildings and all the other energy intensive industries. Again the technologies in energy efficiency rely a lot on the use of rare earths. These include applications in energy efficient lighting, new and more reliable energy storage batteries as well as more efficient energy distribution mechanism. The growing demand for more efficient communication systems, not only in the world of business but also in defence and the military, is another significant driver of the global demand for rare earths. Mobility and miniaturisation, which feature prominently in the current specifications for telecommunications equipment's, rely a lot on the deployment of powerful and efficient magnetic technology. And rare earths have become a much sought after material in the latest magnets used in mobile phones, defence equipment's and computer hardware's. With the rise in the global investments in smart cities and intelligent communities, the demand for such communication products is destined to witness equally prolific expansion. This would inadvertently translate into a rising demand for rare earths. (author)

2011-01-01

273

Ion and electron pressure distributions from the tail plasma sheet to the inner magnetosphere: THEMIS and Geotail observations and comparisons with the RCM simulations  

Science.gov (United States)

Plasma pressure is one of the most important controlling factors in magnetospheric dynamics. Using 3 years of THEMIS data and 11 years of Geotail measurements, we have determined statistically how equatorial ion and electron pressures change from the tail plasma sheet (r~30 Re) to the inner magnetosphere (r~5 Re), and how they vary with the strength of the cross polar-cap potential (CPCP). Both ion and electron pressures increase by at least an order of magnitude from r=30 to 5 Re. With decreasing r, ion pressure becomes slightly larger (a factor of ~15 Re and does not change with CPCP. Inside r~15 Re, the ratio increases with decreasing r and becomes larger with increasing CPCP with larger ratio (up to > 0.5) in the post-midnight sector. To understand the above distributions in the near-Earth plasma sheet and inner magnetosphere, we have simulated ion and electron pressures resulting from particle drift transport using the Rice Convection Model (RCM) and the Tsyganenko 96 magnetic field model (T96) with outer MLT-dependent plasma boundary conditions (at r~20 Re) established from Geotail observations. Despite the simulations are not in force balance, there is qualitative agreement in pressure distributions between simulations and observations. The RCM shows that as particles drift toward smaller r, magnetic drift becomes stronger due to adiabatic energization, while electric drift becomes increasingly affected by eastward corotation. Since electric and magnetic drifts are in the same direction for electrons but in the opposite directions for ions, the combined total drift results in more pronounced MLT asymmetry in electron pressures than ion pressures. As CPCP increases, decrease of cold particle source in the tail results in the density decrease and temperature increase, while enhanced convection moves plasma sheet particles closer to the Earth, resulting in the pressure increase seen at smaller r. We are currently running the RCM with force-balance magnetic fields so that quantitative comparisons can be made. In addition, we are evaluating magnetic field configuration, field aligned currents, and ionospheric mapping of the equatorial structures from 3D force-balanced magnetospheric configurations that we are now able to establish using the observed pressures and a force balance magnetic field code.

Wang, C.; Gkioulidou, M.; Zaharia, S. G.; Lyons, L. R.; Angelopoulos, V.; Nagai, T.; Lui, A.

2010-12-01

274

Galileo Earth Views (WMS)  

Science.gov (United States)

The Galileo spacecraft was launched from the Space Shuttle Atlantis on October 18, 1989 on a six-year trip to Jupiter. On the way, the trajectory of the spacecraft took it past Venus once and Earth twice. Galileo took the Earth images in this animation just after the first flyby of the Earth, on December 11 and 12, 1990. This six-hour sequence of images taken two minutes apart clearly shows how the Earth looks from space and how fast (or slow) the cloud features change when looked at from a distance. The path of the sun can be seen crossing Australia by its reflection in the nearby ocean, and the terminator region between night and day can be seen moving across the Indian Ocean. In the original images, the Earths rotation is so dominant that cloud movement is hard to see, but these images have been mapped to the Earth is such a way that a viewer can watch just the clouds move in the ocean around Antarctica or across the Austrailian land mass. In this animation, New Zealand can ony be seen as a stationary disturbance under a moving cloud bank. The black area with the sharp boundary to the north and east of Australia is the side of the Earth that could not be seen from Galileos position.

Mitchell, Horace

2004-08-13

275

Accretion of the Earth.  

UK PubMed Central (United Kingdom)

The origin of the Earth and its Moon has been the focus of an enormous body of research. In this paper I review some of the current models of terrestrial planet accretion, and discuss assumptions common to most works that may require re-examination. Density-wave interactions between growing planets and the gas nebula may help to explain the current near-circular orbits of the Earth and Venus, and may result in large-scale radial migration of proto-planetary embryos. Migration would weaken the link between the present locations of the planets and the original provenance of the material that formed them. Fragmentation can potentially lead to faster accretion and could also damp final planet orbital eccentricities. The Moon-forming impact is believed to be the final major event in the Earth's accretion. Successful simulations of lunar-forming impacts involve a differentiated impactor containing between 0.1 and 0.2 Earth masses, an impact angle near 45 degrees and an impact speed within 10 per cent of the Earth's escape velocity. All successful impacts-with or without pre-impact rotation-imply that the Moon formed primarily from material originating from the impactor rather than from the proto-Earth. This must ultimately be reconciled with compositional similarities between the Earth and the Moon.

Canup RM

2008-11-01

276

Accretion of the Earth.  

Science.gov (United States)

The origin of the Earth and its Moon has been the focus of an enormous body of research. In this paper I review some of the current models of terrestrial planet accretion, and discuss assumptions common to most works that may require re-examination. Density-wave interactions between growing planets and the gas nebula may help to explain the current near-circular orbits of the Earth and Venus, and may result in large-scale radial migration of proto-planetary embryos. Migration would weaken the link between the present locations of the planets and the original provenance of the material that formed them. Fragmentation can potentially lead to faster accretion and could also damp final planet orbital eccentricities. The Moon-forming impact is believed to be the final major event in the Earth's accretion. Successful simulations of lunar-forming impacts involve a differentiated impactor containing between 0.1 and 0.2 Earth masses, an impact angle near 45 degrees and an impact speed within 10 per cent of the Earth's escape velocity. All successful impacts-with or without pre-impact rotation-imply that the Moon formed primarily from material originating from the impactor rather than from the proto-Earth. This must ultimately be reconciled with compositional similarities between the Earth and the Moon. PMID:18826928

Canup, Robin M

2008-11-28

277

The Dynamic Earth  

Science.gov (United States)

The reason we know that glaciers covered certain areas of the globe while continental plates buckled elsewhere is because of rocks. Thanks to these gatekeepers of the past, we are better able to understand the earth's history and the present. The National Museum of Natural History, Smithsonian Institution, offers this really interactive and engaging site to teach about science of the earth. The three main sections of the site include: Rocks at Earth's Surface, Rocks Below Earth's Surface, and Mining. The detailed interactive modules in each section take the visitor from learning about the different minerals that make up gneiss, granite, and feldspar, to touring three mines in the United States. As the site states, "Earth's history is written on pages of stone. Since our planet's birth 4.6 billion years ago, rocks have been continually forming and, over time, changing from one kind to another. Every rock preserves part of this ancient and ongoing story." And, this great Web site takes you through this story of the earth's history exceptionally well. Those interested in earth science, students, and teachers will surely find this site useful. And, although the best viewing is by using Flash, there is a text-only option as well.

278

Production of Freshwater and Energy from Earth’s Atmosphere  

Directory of Open Access Journals (Sweden)

Full Text Available The author offers a new, cheap method for the extraction of freshwater from the Earth’s atmosphere. The suggested method is fundamentally dictinct from all existing methods that extract freshwater from air. All other industrial methods extract water from a saline water source (in most cases from seawater). This new method may be used at any point in the Earth except the Polar Zones. It does not require long-distance freshwater transportation. If seawater is not utilized for increasing its productivity, this inexpensive new method is very environmentally-friendly. The author’s method has two working versions: 1) In the first variant warm (or hot) atmospheric air is lifted by the inflatable tube in a high altitude and atmospheric water vapor is condensed into freshwater: 2) in the second version, the warm air is pumped 20-30 meters under the sea-surface. In the first version, wind and solar heating of air are used for causing air flow. In version 2) wind and fans are used for causing air movment. The first method does not need energy, the second needs a small amount. Moreover, in variant 1) the freshwater has a high pressure (> 30 or more atm) and can be used for production of energy such as electricity and in that way the freshwater cost is lower. For increasing the productivity the seawater is injected into air and a solar air heater may be used. The solar air heater produces a huge amount of electricity as a very powerful electrical generation plant. The offered electricity installation is 100 - 200 times cheaper than any common electric plant of equivalent output.

Alexander Bolonkin

2011-01-01

279

Study on earth pressure at equilibrium and horizontal subgrade reaction coefficient of an earth wall embedment in braced excavation work on clayey soil; Nenseido jiban ni okeru kussaku dodomeheki neirebu no heiko doatsu to suihei jiban hanryoku keisu ni kansuru kenkyu  

Energy Technology Data Exchange (ETDEWEB)

Concerning the excavated soil retaining work, examination was conducted about the equilibrium soil pressure and horizontal subgrade reaction coefficient using the finite element method and a formula was proposed including highly sensitive parameters. This formula, conventional calculation method, and values actually measured on site were compared with each other, and it was found that the factors that affect the equilibrium soil pressure are excavation depth, excavation width, coefficient of soil pressure at rest, weight per unit volume of soil, and shear resistance on the soil retaining wall surface, and that the factors that affect the horizontal subgrade reaction coefficient are excavation width, coefficient of soil pressure at rest, penetration depth of the soil retaining wall, and subgrade deformation coefficient. The measurements obtained at an LNG underground tank, where the horizontal displacement of the soil retaining wall is relatively small, were compared with the equilibrium soil pressure and horizontal subgrade reaction coefficient calculated using the proposed formula, and then it was found that there was excellent approximation between them though with a little error. It was concluded that the proposed formula is generally applicable to the calculation of equilibrium soil pressure and horizontal subgrade reaction coefficient, and is good for practical use in excavated soil retaining work. 12 refs., 33 figs., 15 tabs.

Nakamura, H.; Hirashima, K.

1996-03-20

280

The balanced scorecard: sustainable performance assessment for forensic laboratories.  

UK PubMed Central (United Kingdom)

The purpose of this article is to introduce the concept of the balanced scorecard into the laboratory management environment. The balanced scorecard is a performance measurement matrix designed to capture financial and non-financial metrics that provide insight into the critical success factors for an organization, effectively aligning organization strategy to key performance objectives. The scorecard helps organizational leaders by providing balance from two perspectives. First, it ensures an appropriate mix of performance metrics from across the organization to achieve operational excellence; thereby the balanced scorecard ensures that no single or limited group of metrics dominates the assessment process, possibly leading to long-term inferior performance. Second, the balanced scorecard helps leaders offset short term performance pressures by giving recognition and weight to long-term laboratory needs that, if not properly addressed, might jeopardize future laboratory performance.

Houck M; Speaker PJ; Fleming AS; Riley RA Jr

2012-12-01

 
 
 
 
281

Height, surface firmness, and visual reference effects on balance control.  

UK PubMed Central (United Kingdom)

OBJECTIVES: To investigate the effects of height, surface firmness, and visual reference on standing balance in construction workers. DESIGN: Controlled laboratory study with balanced repeated measures. PARTICIPANTS: Twenty four construction workers. SETTING: Test subjects performed standing tasks at ground level as well as at 3 m and 9 m high balconies on firm or deformable surfaces with close visual references included or excluded from their visual field. METHODS: Standing balance was determined from center of pressure as measured by a force platform. Dependent variables were root mean square of sway in medial-lateral and anterior-posterior directions, area of sway, and velocity of sway. RESULTS: Heights without close visual references significantly increased all sway parameters. The effect of height in conditions without close visual references increased dramatically on deformable surfaces. CONCLUSIONS: Elevated work environments and deformable work surfaces negatively affect balance and may be associated with increased risk of fall incidents. Appropriate close visual references increase the ability to maintain balance.

Simeonov P; Hsiao H

2001-09-01

282

The Earth's Magnetic Interior  

CERN Document Server

This volume combines review and solicited contributions, related to scientific studies of Division I of IAGA presented recently at its Scientific Assembly in Sopron in 2009. The book is aimed at intermediate to advanced readers dealing with the Earth's magnetic field generation, its historical records in rocks and geological formations - including links to geodynamics and magnetic dating, with magnetic carriers in earth materials, electromagnetic induction and conductivity studies of the Earth interior with environmental applications of rock magnetism and electromagnetism. The aim of the book

Petrovsky, Eduard; Harinarayana, T; Herrero-Bervera, Emilio

2011-01-01

283

Project Earth Science  

CERN Multimedia

Project Earth Science: Astronomy, Revised 2nd Edition, involves students in activities that focus on Earth's position in our solar system. How do we measure astronomical distances? How can we look back in time as we gaze across vast distances in space? How would our planet be different without its particular atmosphere and distance to our star? What are the geometries among Earth, the Moon, and the Sun that yield lunar phases and seasons? Students explore these concepts and others in 11 teacher-tested activities.

Holt, Geoff

2011-01-01

284

Near-earth magnetotail shape and size as determined from the magnetopause flaring angle  

Energy Technology Data Exchange (ETDEWEB)

Knowledge of the average size and shape of the near-Earth magnetotail is an essential element for our understanding of the magnetospheric response to the influence of the solar wind. An empirical model of the near-Earth magnetotail has been developed, which depends upon distance downtail (x{sub GSM}), the solar wind momentum flux ({rho}v{sup 2}{sub SW}), and the Z{sub GSM} component of the interplanetary magnetic field (IMF B{sub z}). This model has been created by using the pressure balance relation to calculate a set of flare angles for the nightside magnetopause in the region {minus}22 R{sub E} {le}X{sub GSM} {le}{minus}10 R{sub E}. Observations of the magnetic field in the lobe by ISEE 2 and simultaneous observations of the magnetic field and plasma properties of the solar wind by IMP 8 were used to determine the internal and external pressure components, respectively. Examination of calculated flare angle values reveal a dependence upon downtail distance and {rho}v{sup 2}{sub SW}. Normalized to the median downtail distance and dynamic pressure, the angle of flare of the magnetopause is found to increase linearly with decreasing B{sub Z} when the IMF is southward, but there is little variation when the IMF is northward. The empirical function derived for the flaring angle of the magnetotail is used to determine a relation for the radius of the tail. Comparisons with previous empirical models and results are also performed. In addition, values of magnetic flux within the magnetotail are calculated for times of sudden impulse events. 43 refs., 17 figs., 4 tabs.

Petrinec, S.M.; Russell, C.T. [Univ. of California, Los Angeles, CA (United States)

1996-01-01

285

Visualizing Phylogenetic Tree Balance  

UK PubMed Central (United Kingdom)

A certain graphical display of the sizes of clades involved in thesplits of a phylogenetic tree both demonstrates the known poor fit ofthe simplest stochastic null models and suggests alternative mathematicalmodels which appear to give a better fit.The study of phylogenetic tree shape, and discussion of whether conclusionsconcerning macroevolutionary process may legitimately be inferredfrom tree shape, have a large literature, recently surveyed in detail by Mooersand Heard [8], to which we refer the reader for background. This papergives a statistician's comments on two related aspects of this subject. Inbrief, we argue (i) it would be desirable to consider some one-parameterfamily of stochastic null models for trees, where the parameter measures"balance" of a typical tree predicted by the model; (ii) for a large tree, it isvastly more informative to use a certain scatter diagram to exhibit balancevisually than to simply calculate some numerical index of balance.A 1-PARA...

David J. Aldous

286

Earth: A Ringed Planet?  

Science.gov (United States)

Among the most beautiful findings of the Space Age have been the discoveries of planetary rings. Not only Saturn but also Jupiter, Uranus and Neptune have rings; Saturn’s ring system has structures newly discovered; even Saturn's moon Rhea itself has a ring. All these are apparently supplied by material from the planetary moons (Rhea's ring by Rhea itself). The question naturally arises, why should the Earth not have a ring, and on the other hand, if it does, why has it not been observed? No rings have yet been observed in the inner solar system, but after all, rings in the inner solar system might simply tend to be fainter and more transient than those of the outer solar system: the inner solar system is more affected by the solar wind, and the Sun’s perturbing gravitational influence is greater. J.A. O’Keefe first suggested (1980) that Earth might have a ring system of its own. An Earth ring could account for some climate events. O’Keefe remarked that formation or thickening of a ring system in Earth’s equatorial plane could drive glaciation by deepening the chill of the winter hemisphere. (It is very well established that volcanic dust is an effective agent for the extinction of sunlight; this factor can be overwhelmingly apparent in eclipse observations.) O’Keefe died in 2000 and the speculation was not pursued, but the idea of an Earth ring has a prima facie reasonableness that calls for its renewed consideration. The program of this note is to hypothesize that, as O’Keefe proposed: (a) an Earth ring system exists; (b) it affects Earth's weather and climate; (c) the tektite strewn fields comprise filaments of the ring fallen to Earth's surface on various occasions of disturbance by comets or asteroids. On this basis, and drawing on the world's weather records, together with the Twentieth Century Reanalysis by NCEP/CIRES covering the period 1870-2010 and the geology of the tektite strewn fields, we herein propose the hypothesized Earth ring system’s orbital elements and structure. Our work concludes that rings may exist in Earth’s equatorial plane and in the plane of the lunar orbit, that such rings are filamentary structures comprising segments of geologically homogeneous material flung into earth’s orbit at distinct periods of lunar volcanism, and that earth’s weather may indeed be very strongly affected by the rings. In closing, until the time of the lunar landing in 1969, the moon was considered geologically dead. But today, we have multiple lines of evidence that the Moon is still volcanically active. According to our study, this volcanism may affect weather and climate considerably. If lunar volcanism and weather on Earth are linked, then a satisfactory understanding of lunar volcanism is called for by considerations of human welfare. The subsistence farmer has an immediate need to know what is true about our Moon; food security depends on it.

Hancock, L. O.; Povenmire, H.

2010-12-01

287

Improving Balance with Tai Chi  

Science.gov (United States)

... 837-8428 · INFO@VESTIBULAR.ORG · WWW.VESTIBULAR.ORG Improving Balance with Tai Chi By the Vestibular Disorders ... program has been shown to be effective in improving functional balance and reducing falls by 55% in ...

288

Selection of hydronic balancing valves  

Energy Technology Data Exchange (ETDEWEB)

This paper describes the selection and setting of balance valves, which, when properly applied in the design of a hydronic system, will result in a balanced system, thus preventing over pumping without excessive energy costs.

Ahlgren, R.C.E. [ITT Fluid Handling, Morton Grove, IL (United States)

1998-10-01

289

Vibrations of Earth Dams.  

Science.gov (United States)

Contents: Vibration studies of dams built from local materials; Spectral features of the vibrations of an earthen structure during earthquake; Vibrations of the foundation and the body of the dam during short-period microseisms; Vibrations of earth dams d...

S. V. Medvedev

1974-01-01

290

Earth's Variable Rotation.  

UK PubMed Central (United Kingdom)

Recent improvements in geodetic data and practical meteorology have advanced research on fluctuations in the Earth's rotation. The interpretation of these fluctuations is inextricably linked with studies of the dynamics of the Earth-moon system and dynamical processes in the liquid metallic core of the Earth (where the geomagnetic field originates), other parts of the Earth's interior, and the hydrosphere and atmosphere. Fluctuations in the length of the day occurring on decadal time scales have implications for the topography of the core-mantle boundary and the electrical, magnetic, and other properties of the core and lower mantle. Investigations of more rapid fluctuations bear on meteorological studies of interannual, seasonal, and intraseasonal variations in the general circulation of the atmosphere and the response of the oceans to such variations.

Hide R; Dickey JO

1991-08-01

291

Environment and the Earth  

Science.gov (United States)

The Environment and the Earth class at the University of South Carolina participated in a campus environmental service-learning project where students collected data lighting, water fixtures, recycling bins, and trash in five academic buildings.

Compiled by Suzanne Savanick, Science Education Resource Center. Based on Bixby et al. (2003), Ecology on Campus: Service Learning in Introductory Environmental Courses, Journal of College Science Teaching, v. 32, n.5, o, 327-331.

292

Earth's electric field  

International Nuclear Information System (INIS)

[en] The earth becomes charged during thunderstorm activity and discharges through the weak conducting atmosphere. Balloon and rocket studies infer that a high altitude electric field penetrates virtually unattenuated through the atmosphere, at least as far as balloon heights. The field has two primary sources. At low and mid latitudes, interaction between the earth's magnetic field and the neutral wind creates electric fields. At latitudes above 600, the high altitude electrical structure is dominated by the interaction between the solar wind and the earth's magnetic field. The auroral light is emitted by atmospheric atoms and molecules excited by electrons with potentials of many thousands volts. The potentials are induced by the solar wind. Recent satellite data shows that the electrons get this energy by passing through a localized electric field about 6000 km above the auroral zone. Several rocket and satellite experiments used to study the earth's electric field are discussed

1978-01-01

293

Exploring Magnetism on Earth  

Science.gov (United States)

Understanding the power of magnetism on Earth isn't always easy, and students and teachers alike will be glad to find out about this handy guide to the subject. Created by experts at NASA, this 15-page teacher's guide was designed in partnership with other educators at Berkeley as well as several other participating institutions. The guide contains problems which examine Earth's changing magnetic field in time and space, and how these changes can impact navigation on Earth's surface. In terms of specific activities, the guide includes exercises on navigating the earth with a compass, the declining magnetic field, and the reversal of magnetic polarity. Each of these activities is explained in detail, and they all include relevant illustrations, graphs, questions, and an answer key.

Odenwald, Sten F.; Peticolas, Laura; Craig, N. (Nahide)

2005-01-01

294

Mercury, Venus, and Earth!  

Science.gov (United States)

You will compare and contrast Mercury, Venus, and Earth. While looking at these different websites, use the information to fill in your handout of a column chart and on the back answer the questions you are asked on here. First view this website and record on your chart the distance from the sun Mercury,Venus, and Earth are. Now, learn about Mercury! What is the surface ...

Bschiffer

2009-10-21

295

EarthNow!  

Science.gov (United States)

EarthNow! displays live or recent acquisitions from the Landsat 5 and Landsat 7 satellites as they pass over North America. When these satellites pass within range of the U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center, data imagery is downloaded and displayed in near-real time. When the satellites are out of range of the South Dakota ground station at the EROS Center, recent acquisitions are displayed.

Geological Survey (U.S.)

2008-01-01

296

Field reversing magnetotail current sheets: earth, Venus, and Comet Giacobini-Zinner  

International Nuclear Information System (INIS)

[en] This dissertation examines the field reversing magnetotail current sheets at the earth, Venus, and Comet Giacobini-Zinner. In the near earth study a new analysis technique is developed to calculate the detailed current density distributions within the cross tail current sheet for the first time. This technique removes the effects of a variable sheet velocity by inverting intersatellite timings between the co-orbiting satellites ISEE-1 and -2. Case studies of three relatively geomagnetically quiet crossings are made; sheet thicknesses and peak current densities are ?1-5 x 104 km and ?5-50 nA/m2. Current density distributions reveal a high density central region, lower density shoulders, and considerable fine structure throughout. In the Venus study another new analysis technique is developed to reconstruct the average tail configuration from a correlation between field magnitude and draping angle in a large statistical data set. In the comet study, high resolution magnetic field and plasma electron data from the ICE traversal of Giacobini-Zinner are combined for the first time to determine the tail/current sheet geometry and calculate certain important but unmeasured local ion and upstream properties. Pressure balance across the tail gives ion temperatures and betas of ?1.2 x 105 K and ?40 in the center of the current sheet to ?1 x 106 K and ?3 in the outer lobes. Axial stress balance shows that the velocity shear upstream near the nucleus is >6 (?1 at ICE), and that a region of strongly enhanced mass loading (ion source rate ?24 times that upstream from lobes) exists upstream from the current sheet. The integrated downtail mass flux is ?2.6 x 1026 H2O+/sec, which is only ?1% of the independently determined total cometary efflux. 79 refs., 37 figs

1986-01-01

297

Field reversing magnetotail current sheets: earth, Venus, and Comet Giacobini-Zinner  

Energy Technology Data Exchange (ETDEWEB)

This dissertation examines the field reversing magnetotail current sheets at the earth, Venus, and Comet Giacobini-Zinner. In the near earth study a new analysis technique is developed to calculate the detailed current density distributions within the cross tail current sheet for the first time. This technique removes the effects of a variable sheet velocity by inverting intersatellite timings between the co-orbiting satellites ISEE-1 and -2. Case studies of three relatively geomagnetically quiet crossings are made; sheet thicknesses and peak current densities are approx.1-5 x 10/sup 4/ km and approx.5-50 nA/m/sup 2/. Current density distributions reveal a high density central region, lower density shoulders, and considerable fine structure throughout. In the Venus study another new analysis technique is developed to reconstruct the average tail configuration from a correlation between field magnitude and draping angle in a large statistical data set. In the comet study, high resolution magnetic field and plasma electron data from the ICE traversal of Giacobini-Zinner are combined for the first time to determine the tail/current sheet geometry and calculate certain important but unmeasured local ion and upstream properties. Pressure balance across the tail gives ion temperatures and betas of approx.1.2 x 10/sup 5/ K and approx.40 in the center of the current sheet to approx.1 x 10/sup 6/ K and approx.3 in the outer lobes. Axial stress balance shows that the velocity shear upstream near the nucleus is >6 (approx.1 at ICE), and that a region of strongly enhanced mass loading (ion source rate approx.24 times that upstream from lobes) exists upstream from the current sheet. The integrated downtail mass flux is approx.2.6 x 10/sup 26/ H/sub 2/O+/sec, which is only approx.1% of the independently determined total cometary efflux. 79 refs., 37 figs.

McComas, D.J.

1986-09-01

298

Simulations of micrometeoroid interactions with the Earth atmosphere  

CERN Document Server

Micrometeoroids (cosmic dust with size between a few $\\mu$m and $\\sim$1 mm) dominate the annual extraterrestrial mass flux to the Earth. We investigate the range of physical processes occurring when micrometeoroids traverse the atmosphere. We compute the time (and altitude) dependent mass loss, energy balance, and dynamics to identify which processes determine their survival for a range of entry conditions. We develop a general numerical model for the micrometeoroid-atmosphere interaction. The equations of motion, energy, and mass balance are simultaneously solved for different entry conditions (e.g. initial radii, incident speeds and angles). Several different physical processes are taken into account in the equation of energy and in the mass balance, in order to understand their relative roles and evolution during the micrometeoroid-atmosphere interaction. In particular, to analyze the micrometeoroid thermal history we include in the energy balance: collisions with atmospheric particles, micrometeoroid radi...

Briani, G; Shore, S N; Pupillo, G; Passaro, A; Aiello, S

2013-01-01

299

Energy balance equivalents to the Koeppen-Geiger climatic regions  

Energy Technology Data Exchange (ETDEWEB)

The Koeppen-Geiger world map of climatic regions was related to Budyko's world atlas of the heat balance of the earth in order to evaluate the annual march of the components of the surface energy balance for every climate area depicted on the Koeppen-Geiger map. Thus, for each single area of the Koeppen-Geiger map, denoted by the well-known combination of two or three letters of the climate classification formula, an energy balance diagram could be constructed. Finally all diagrams for the same climate (i.e. for the same letter combination, for example Aw or BSk) were compiled in one figure to easily compare their general features and structure. The result of this comparison is, that each letter combination (only one, namely the BSh-climate, being excepted) shows a distinct structure of its energy balance diagram. Thus the Koeppen-Geiger classification is unambiguously related to a distinct structure of the annual course of the components of the surface energy balance. The typical features of these energy balance diagrams are displayed in Figures 8 to 17 and, after normalization, in Figure 28. A description is given in Section 4. Some exceptions occur for transitional regions within the classification. For the BSh-climates five subtypes could be defined. (orig.)

Alkhalaf, A.; Kraus, H.

1993-01-01

300

Thermal History of Planetary Objects: From Asteroids to super-Earths, from plate-tectonics to life (Runcorn-Florensky Medal Lecture)  

Science.gov (United States)

Convection in the interiors of planetesimals (asteroids), planets, and satellites is driving the thermal and chemical evolution of these bodies including the generation of possible magnetic fields. The wide size range induces a wide of range of time scales from hundreds of thousands of years for small planetesimals to a few tens of Gigayears for massive super-Earths. Evolution calculations are often based on energy (and entropy) balances parameterizing the transport properties of the interior in suitable ways. These thereby allow incorporating (in parameterized forms) interesting physical processes that depend in one way or another on the transport properties of the interior. The interior will usually be chemically layered in mantles and cores and include ice layers if icy satellites are considered. In addition to magnetic field generation calculated via energy balances of the core and using semi-empirical dynamo strength relations, processes that can be considered include sintering and compaction for small bodies and mantle (or ice) melting, differentiation and even continental growth for full-scaled terrestrial planets. The rheology of the interior is considered temperature and pressure dependent and the concentration of volatiles can be important. For super-Earths, probably the most critical consideration is how the mantle rheology would vary with pressure and thus with depth. It is possible that the increasing pressure will frustrate deep mantle convection thereby reducing the vigor of mantle convection. Possibly, the generation of a magnetic field in a putative iron-rich core will be impossible, if super-Earths at all have earth-like cores. On a much smaller scale, the decay of short-lived radioactives suffices to heat and melt planetesimals, the melting being helped by the low thermal conductivity of the initially porous body. This allows planets to form from pre-differentiated planetesimals thus helping to differentiate and form cores rapidly. On active planets - like the Earth - the volatile budget matters for the interior evolution. With plate tectonics, large-scale volatile cycles are invoked. On the Earth, even the biosphere is speculated to interact with the interior. It has been argued (e.g., Rosing et al. 2006; Sleep et al, 2012) that the formation of continents could be a consequence of bioactivity harvesting solar energy through photosynthesis to help build the continents and that the mantle should carry a chemical biosignature. A model is presented that includes mantle convection, mantle water vapor degassing at mid-oceanic ridges and regassing through subduction zones, continental crust formation and erosion and water storage and transport in a porous oceanic crust that includes hydrous mineral phases. The biosphere enters the model through its effect on continental erosion and through a reduction of the activation barrier to metamorphic reactions (e.g., Kim et al., 2004) in sediment layers. An abiotic world is found to have a much drier mantle than the present Earth but may have a similar surface coverage by continents. The reduced rate of continental crust production on the abiotic world would be balanced by a reduced rate of continent erosion. Through the effect of water on the mantle rheology, the biotic world would tend to be tectonically more active and have a more rapid long-term carbon-silicate cycle. J. Kim, H. Dong, J. Seabaugh, S. W. Newell, D. D. Eberl, Science 303, 830-832, 2004 N. H. Sleep, D. K. Bird, E. Pope, Annu. Rev. Earth Planet. Sci. 40, 277-300, 2012 M. T. Rosing, D. K. Bird, N. H. Sleep, W. Glassley, F. Albarede, Paleo3 232, 90-113, 2006

Spohn, Tilman

2013-04-01

 
 
 
 
301

High-pressure elastic behavior of Ca4La6(SiO4)6(OH)2 a synthetic rare-earth silicate apatite: a powder X-ray diffraction study up to 9.33 GPa  

Science.gov (United States)

The compression behavior of a synthetic Ca4La6(SiO4)6(OH)2 has been investigated to about 9.33 GPa at 300 K using in situ angle-dispersive X-ray diffraction and a diamond anvil cell. No phase transition has been observed within the pressure range investigated. The values of zero-pressure volume V 0, K 0, and K0' refined with a third-order Birch-Murnaghan equation of state are V 0 = 579.2 ± 0.1 Å3, K 0 = 89 ± 2 GPa, and K0' = 10.9 ± 0.8. If K0' is obtained as 110 ± 2 GPa. Analysis of axial compressible modulus shows that the a-axis (K a0 = 79 ± 2 GPa) is more compressible than the c-axis (K c0 = 121 ± 7 GPa). A comparison between the high-pressure elastic response of Ca4La6(SiO4)6(OH)2 and the iso-structural calcium apatites is made. The possible reasons of the different elastic behavior between Ca4La6(SiO4)6(OH)2 and calcium apatites are discussed.

Fan, Dawei; Wei, Shuyi; Ma, Maining; Chen, Zhiqiang; Li, Baosheng; Xie, Hongsen

2013-09-01

302

Arm movement effect on balance.  

UK PubMed Central (United Kingdom)

The background research shows a high incidence of falls and loss of balance related injuries, which cause serious consequences to individual health and quality of life, as well as substantial healthcare impact in services and costs. The literature review emphasizes that arm movements have a potentially significant effect on balance, and indentifies the use of balance boards as a relevant and meaningful tool for dynamic balance evaluation. The primary objective of this initial study was to develop a method to test and evaluate the effect of arm movements on the maintenance of postural stability. Further we investigated the impact of dominant and non-dominant arms, the reaction time of arms, and the amount of activity of arms related to dynamic balance control. The study applied an accelerometer-based balance board test to measure postural stability as related to arm movements. The evaluation consists of accelerometers placed on the two arms and the balance board. Data were acquired from four different subjects and processed accordingly. The finding verified that arms play an important role in the improvement of balance. Our findings suggest that the dominant arm is more active in balance control and that the movement of arms most often occurs just prior to and during loss of balance. The results also suggest that the amount of arm movement activity directly relates to balance control and the use of the dominant arm.

Shafeie M; Manifar S; Milosevic M; McConville KM

2012-01-01

303

Pan Balance-Expressions  

Science.gov (United States)

This interactive pan balance allows students to enter numeric or algebraic expressions and investigate the important concept of equivalence as well as practice arithmetic and algebraic skills. Users place an expression in each of the red and blue pans. These expressions may or may not include the variable x. If the expression is algebraic, a value for x is entered or adjusted by moving the slider. As the value of x changes, the results will be weighed and graphed. Instructions and exploration directions and questions are included.

2011-01-01

304

Dialysis unphysiology and sodium balance.  

UK PubMed Central (United Kingdom)

Dialysis unphysiology was first discussed by Carl Kjellstrand in 1975 for the possible negative effects of the unphysiology of intermittent dialysis treatment. Current hemodialysis practices are still unphysiologic because they cannot keep blood chemistries within normal limits, both before and after dialysis. In addition, the discontinuous nature of hemodialysis causes saw-tooth volume fluctuations, and the extracellular fluid volume expansion during the interdialytic period may lead to hypertension and adverse cardiovascular consequences. Sodium, which is accumulated over the interdialytic period, may be divided into two fractions. The one is the fraction of osmotically active sodium which is mainly confined to the extracellular space, and the other is that of water-free (osmotically inactive) sodium which diffuses into the intracellular space. Both contribute to the pathogenesis of hypertension because the former may act to expand extracellular fluid volume and the latter may cause vasoconstriction in the long run by increasing cytosolic concentration of calcium in the vascular smooth muscle cells. Even in intensive hemodialysis, it may take several weeks to months for water-free sodium storage in the vascular smooth muscle cells to be relieved. This may be an explanation for the lag phenomenon, i.e., the delay of blood pressure decrease after normalization of extracellular fluid volume shown in the Tassin experience. Modest restriction of dietary sodium intake, the dialytic session length long enough to maintain a high ultrafiltration volume, and the reasonably low dialysate sodium concentration are required to avoid unphysiology of positive sodium balance in current hemodialysis practice.

Kim GH

2009-12-01

305

Electronic structure and properties of rare earth and actinide intermetallics  

International Nuclear Information System (INIS)

There are 188 contributions, experimental and theoretical, a few on rare earth and actinide elements but mostly on rare earth and actinide intermetallic compounds and alloys. The properties dealt with include 1) crystal structure, 2) magnetic properties and magnetic structure, 3) magnetic phase transformations and valence fluctuations, 4) electrical properties and superconductivity and their temperature, pressure and magnetic field dependence. A few papers deal with crystal growth and novel measuring methods. (G.Q.).

1984-01-01

306

Balance ability and athletic performance.  

Science.gov (United States)

The relationship between balance ability and sport injury risk has been established in many cases, but the relationship between balance ability and athletic performance is less clear. This review compares the balance ability of athletes from different sports, determines if there is a difference in balance ability of athletes at different levels of competition within the same sport, determines the relationship of balance ability with performance measures and examines the influence of balance training on sport performance or motor skills. Based on the available data from cross-sectional studies, gymnasts tended to have the best balance ability, followed by soccer players, swimmers, active control subjects and then basketball players. Surprisingly, no studies were found that compared the balance ability of rifle shooters with other athletes. There were some sports, such as rifle shooting, soccer and golf, where elite athletes were found to have superior balance ability compared with their less proficient counterparts, but this was not found to be the case for alpine skiing, surfing and judo. Balance ability was shown to be significantly related to rifle shooting accuracy, archery shooting accuracy, ice hockey maximum skating speed and simulated luge start speed, but not for baseball pitching accuracy or snowboarding ranking points. Prospective studies have shown that the addition of a balance training component to the activities of recreationally active subjects or physical education students has resulted in improvements in vertical jump, agility, shuttle run and downhill slalom skiing. A proposed mechanism for the enhancement in motor skills from balance training is an increase in the rate of force development. There are limited data on the influence of balance training on motor skills of elite athletes. When the effectiveness of balance training was compared with resistance training, it was found that resistance training produced superior performance results for jump height and sprint time. Balance ability was related to competition level for some sports, with the more proficient athletes displaying greater balance ability. There were significant relationships between balance ability and a number of performance measures. Evidence from prospective studies supports the notion that balance training can be a worthwhile adjunct to the usual training of non-elite athletes to enhance certain motor skills, but not in place of other conditioning such as resistance training. More research is required to determine the influence of balance training on the motor skills of elite athletes. PMID:21395364

Hrysomallis, Con

2011-03-01

307

Balanced ultrafiltration: inflammatory mediator removal capacity.  

UK PubMed Central (United Kingdom)

Ultrafiltration with a hemoconcentrator may remove excess fluid load and alleviate tissue edema and has been universally adopted in extracorporeal circulation protocols during pediatric cardiac surgery. Balanced ultrafiltration is advocated to remove inflammatory mediators generated during surgery. However, whether balanced ultrafiltration can remove all or a portion of the inflammatory mediator load remains unclear. The inflammatory mediator removal capacity of zero-balanced ultrafiltration was measured during pediatric extracorporeal circulation in vitro. Extracorporeal circulation was composed of cardiotomy reservoir, D902 Lilliput 2 membrane oxygenator, and Capiox AF02 pediatric arterial line filter. The Hemoconcentrator BC 20 plus was placed between arterial purge line and oxygenator venous reservoir. Fresh donor human whole blood was added into the circuit and mixed with Ringer's solution to obtain a final hematocrit of 24-28%. After 2 h of extracorporeal circulation, zero-balanced ultrafiltration was initiated and arterial line pressure was maintained at approximately 100 mmHg with Hoffman clamp. The rate of ultrafiltration (12 mL/min) was controlled by ultrafiltrate outlet pressure. Identical volume of plasmaslyte A was dripped into the circuit to maintain stable hematocrit during the 45 min of the experiment. Plasma and ultrafiltrate samples were drawn every 5 min, and concentrations of inflammatory mediators including interleukin-1? (IL-1?), IL-6, IL-10, neutrophil elastase (NE), and tumor necrosis factor-? (TNF-?) were measured. All assayed inflammatory mediators were detected in the ultrafiltrate, demonstrating that the ultrafiltrator may remove inflammatory mediators. However, dynamic observations suggested that the concentration of NE was highest among the five inflammatory mediators in both plasma and ultrafiltrate (P < 0.001). IL-1? had the lowest concentration in plasma, whereas the concentration of TNF-? was the lowest in ultrafiltrate (P < 0.001). Concentrations of all inflammatory mediators in the ultrafiltrate did not increase linearly compared with those in plasma. The respective ultrafiltrate to plasma concentration and amount ratios indicated that the total removal effect of hemoconcentrator on the inflammatory mediators was 4.17 ± 2.68% for IL-1?, 0.64 ± 0.69% for IL-6, 0.24 ± 0.18% for IL-10, 2.84 ± 1.65% for NE, and 0.51 ± 0.81% for TNF-?, respectively. Balanced ultrafiltration may selectively remove inflammatory mediators from serum. Respective ratios of inflammatory mediators in ultrafiltrate compared with plasma, as well as total amount of inflammatory mediators in the ultrafiltrate suggest that balanced ultrafiltration removes a limited portion of the total inflammatory mediator load.

Guan Y; Wan C; Wang S; Sun P; Long C

2012-10-01

308

Balanced ultrafiltration: inflammatory mediator removal capacity.  

Science.gov (United States)

Ultrafiltration with a hemoconcentrator may remove excess fluid load and alleviate tissue edema and has been universally adopted in extracorporeal circulation protocols during pediatric cardiac surgery. Balanced ultrafiltration is advocated to remove inflammatory mediators generated during surgery. However, whether balanced ultrafiltration can remove all or a portion of the inflammatory mediator load remains unclear. The inflammatory mediator removal capacity of zero-balanced ultrafiltration was measured during pediatric extracorporeal circulation in vitro. Extracorporeal circulation was composed of cardiotomy reservoir, D902 Lilliput 2 membrane oxygenator, and Capiox AF02 pediatric arterial line filter. The Hemoconcentrator BC 20 plus was placed between arterial purge line and oxygenator venous reservoir. Fresh donor human whole blood was added into the circuit and mixed with Ringer's solution to obtain a final hematocrit of 24-28%. After 2 h of extracorporeal circulation, zero-balanced ultrafiltration was initiated and arterial line pressure was maintained at approximately 100 mmHg with Hoffman clamp. The rate of ultrafiltration (12 mL/min) was controlled by ultrafiltrate outlet pressure. Identical volume of plasmaslyte A was dripped into the circuit to maintain stable hematocrit during the 45 min of the experiment. Plasma and ultrafiltrate samples were drawn every 5 min, and concentrations of inflammatory mediators including interleukin-1? (IL-1?), IL-6, IL-10, neutrophil elastase (NE), and tumor necrosis factor-? (TNF-?) were measured. All assayed inflammatory mediators were detected in the ultrafiltrate, demonstrating that the ultrafiltrator may remove inflammatory mediators. However, dynamic observations suggested that the concentration of NE was highest among the five inflammatory mediators in both plasma and ultrafiltrate (P hemoconcentrator on the inflammatory mediators was 4.17 ± 2.68% for IL-1?, 0.64 ± 0.69% for IL-6, 0.24 ± 0.18% for IL-10, 2.84 ± 1.65% for NE, and 0.51 ± 0.81% for TNF-?, respectively. Balanced ultrafiltration may selectively remove inflammatory mediators from serum. Respective ratios of inflammatory mediators in ultrafiltrate compared with plasma, as well as total amount of inflammatory mediators in the ultrafiltrate suggest that balanced ultrafiltration removes a limited portion of the total inflammatory mediator load. PMID:22817761

Guan, Yulong; Wan, Caihong; Wang, Shigang; Sun, Peng; Long, Cun

2012-07-23

309

Negative leave balances  

CERN Document Server

Members of the personnel entitled to annual leave and, where appropriate, saved leave and/or compensatory leave are requested to take note of the new arrangements described below, which were recommended by the Standing Concertation Committee (SCC) at its meeting on 1 September 2005 and subsequently approved by the Director-General. The changes do not apply to members of the personnel participating in the Progressive Retirement Programme (PRP) or the Part-time Work as a pre-retirement measure, for whom the specific provisions communicated at the time of joining will continue to apply.  Negative balances in annual leave, saved leave and/or compensatory leave accounts at the end of the leave year (30th September) and on the date on which bonuses are credited to the saved leave account (31st December): Where members of the personnel have a leave account with a negative balance on 30 September and/or 31 December, leave will automatically be transferred from one account to another on the relevant dates in or...

Human Resources Department

2005-01-01

310

Negative leave balances  

CERN Document Server

Members of the personnel entitled to annual leave and, where appropriate, saved leave and/or compensatory leave are requested to take note of the new arrangements described below, which were recommended by the Standing Concertation Committee (SCC) at its meeting on 1Â September 2005 and subsequently approved by the Director-General. The changes do not apply to members of the personnel participating in the Progressive Retirement Programme (PRP) or the Part-time Work as a pre-retirement measure, for whom the specific provisions communicated at the time of joining will continue to apply. Â Negative balances in annual leave, saved leave and/or compensatory leave accounts at the end of the leave year (30th September) and on the date on which bonuses are credited to the saved leave account (31st December): Where members of the personnel have a leave account with a negative balance on 30Â September and/or 31Â December, leave will automatically be transferred from one account to another on the relevant dates i...

Human Resources Department

2005-01-01

311

[Balance in the elderly].  

UK PubMed Central (United Kingdom)

UNLABELLED: Throughout years, the human organism goes through natural aging, having functional and structural changes. The part which is responsible for the corporal balance system also suffers from the aging process, creating great impact for the elderly. AIM: Thus, the present paper aims to study the vestibular function of old people suffering from dizziness, tinnitus and hearing impairment. STUDY DESIGN: Transversal cohort. MATERIAL AND METHOD: 80 elderly individuals from two different groups were evaluated: group A - composed of 38 women and 2 men who belonged to an elderly group from Santa Maria, RS; and group B - composed of 35 women and 5 men with complaints of balance disorders. RESULTS: Both groups were undergone anamnesis (calling attention to aspects concerning the dizziness, tinnitus and the hearing impairment), and the vestibular function evaluation (by using the computerized system of vecto-electronystagmography SCV 5.0). The results displayed a statistical significant difference between both groups, concerning the complaints of dizziness and tinnitus, straightforward in group B. In the hypothetical diagnosis lead by the computerized examination, it was found that most individuals had presented normal diagnosis; however, it was found the predominance of vestibular disorders in the elderly such as Deficit Peripheral Vestibular Syndrome and Irritative Peripheral Vestibular Syndrome. CONCLUSION: It was concluded that the vestibular disorders, according to the vecto-electronystagmography, and to the complaints of dizziness, tinnitus and hearing impairment, are numerically similar in both studied groups.

Ruwer SL; Rossi AG; Simon LF

2005-05-01

312

The Balance Evaluation Systems Test (BESTest) to differentiate balance deficits.  

UK PubMed Central (United Kingdom)

BACKGROUND: Current clinical balance assessment tools do not aim to help therapists identify the underlying postural control systems responsible for poor functional balance. By identifying the disordered systems underlying balance control, therapists can direct specific types of intervention for different types of balance problems. OBJECTIVE: The goal of this study was to develop a clinical balance assessment tool that aims to target 6 different balance control systems so that specific rehabilitation approaches can be designed for different balance deficits. This article presents the theoretical framework, interrater reliability, and preliminary concurrent validity for this new instrument, the Balance Evaluation Systems Test (BESTest). DESIGN: The BESTest consists of 36 items, grouped into 6 systems: "Biomechanical Constraints," "Stability Limits/Verticality," "Anticipatory Postural Adjustments," "Postural Responses," "Sensory Orientation," and "Stability in Gait." METHODS: In 2 interrater trials, 22 subjects with and without balance disorders, ranging in age from 50 to 88 years, were rated concurrently on the BESTest by 19 therapists, students, and balance researchers. Concurrent validity was measured by correlation between the BESTest and balance confidence, as assessed with the Activities-specific Balance Confidence (ABC) Scale. RESULTS: Consistent with our theoretical framework, subjects with different diagnoses scored poorly on different sections of the BESTest. The intraclass correlation coefficient (ICC) for interrater reliability for the test as a whole was .91, with the 6 section ICCs ranging from .79 to .96. The Kendall coefficient of concordance among raters ranged from .46 to 1.00 for the 36 individual items. Concurrent validity of the correlation between the BESTest and the ABC Scale was r=.636, P<.01. LIMITATIONS: Further testing is needed to determine whether: (1) the sections of the BESTest actually detect independent balance deficits, (2) other systems important for balance control should be added, and (3) a shorter version of the test is possible by eliminating redundant or insensitive items. CONCLUSIONS: The BESTest is easy to learn to administer, with excellent reliability and very good validity. It is unique in allowing clinicians to determine the type of balance problems to direct specific treatments for their patients. By organizing clinical balance test items already in use, combined with new items not currently available, the BESTest is the most comprehensive clinical balance tool available and warrants further development.

Horak FB; Wrisley DM; Frank J

2009-05-01

313

Annual review of earth and planetary sciences. Vol. 19  

Energy Technology Data Exchange (ETDEWEB)

Various review papers on earth and planetary sciences are presented. The individual topics addressed include: tectonics of the New Guinea area, interpretation of ancient Eolian and dunes, seismic tomography of the earth's mantle, shock modification and chemistry and planetary geologic processes, the significance of evaporites, the magnetosphere, untangling the effects of burial alteration and ancient soil formation. Also discussed are: pressure-temperature-time paths, fractals in rock physics, earthquake prediction, rings in the ocean, applications of Be{minus}10 to problems in the earth sciences, measurement of crustal deformation using the GPS, physics and physical mechanisms of nuclear winter, experiemental determination of bed-form stability.

Wetherill, G.W.; Albee, A.L.; Burke, K.C. (Carnegie Inst. of Washington, DC (United States) California Inst. of Tech., Pasadena (United States) National Research Council, Washington, DC (United States))

1991-01-01

314

Analysis of pressurizer pressure control system using MAAP5 code  

International Nuclear Information System (INIS)

[en] Full text of publication follows. MAAP4 code is a severe accident analysis code, widely used in nuclear industry. Pressurizer response plays an important role in transient and accident analysis. However, only simplified pressurizer pressure control system model is included in MAAP4 code. The purpose of the paper is to modify the pressurizer pressure control system model in MAAP4 without compiling the code, promoting the simulation capability and accuracy of the MAAP4 code. The typical proportional and integral (PI) controller model is successfully coupled with current code without compiling. Typical control system analysis is analyzed using MAAP4. Furthermore, the characteristic of PI controller is demonstrated, which reduces the steady state error to zero. With the revised pressurizer pressure control system, the transient responses are more realistic. It can be coupled with balance of plant model for whole plant simulation in MAAP5 code in the near future. (authors)

2011-01-01

315

Earth on Fire  

Science.gov (United States)

Earth on Fire belongs to a series of online modules entitled Exploring the Environment. Emphasizing an integrated approach to environmental earth science through problem-based learning, this module asks students to examine global warming through supplying evidence for its existence, identifying its sources, and providing ways to minimize its impact. To accomplish this goal, the site provides five links that lead students to information concerning global warming. These links include information pertaining to the carbon cycle, possible culprits of warming such as greenhouse gasses, solar output, the Earth's orbit, solutions to global warming, connections between global warming and natural disasters, and remote sensing. Various activities for students include a remote sensing analysis of burning biomass during the 1988 Yellowstone fires. Hyperlinked background resources are available throughout the site and offer more detail for student investigations. A glossary, teacher resources, related links, and a general description of the problem-based learning model compliment the site.

2000-11-21

316

Specification and performance of testing and balancing in biological facilities  

Energy Technology Data Exchange (ETDEWEB)

Biologics facilities for pilot, clinical trial, and manufacturing applications have special testing and balancing requirements. The testing and balancing function can ensure the integrity of the design intent through start-up; it provides valuable test data for clean room certification and validation while providing the owner long-term mechanical system reliability. One of the most important functions of the heating, ventilating, and air-conditioning (HVAC) systems in these facilities is the maintenance of different pressures between rooms. A testing and balancing procedure to accomplish this is not addressed effectively by NEBB or AABC standards. A detailed specification of the testing and balancing procedures and incorporation of all system design data in the testing and balancing contract package is essential to the ultimate success of the project. The pressure differential instrumentation furnished and installed by the controls contractor should be calibrated during the testing and balancing activity. A final verification of the system performance by the engineer must be conducted prior to beginning clean room testing and certification activities.

Burns, J.T.; Milburn, W.F.

1999-07-01

317

Google Earth Engine  

Science.gov (United States)

The Google Earth Engine platform is a system designed to enable petabyte-scale, scientific analysis and visualization of geospatial datasets. Earth Engine provides a consolidated environment including a massive data catalog co-located with thousands of computers for analysis. The user-friendly front-end provides a workbench environment to allow interactive data and algorithm development and exploration and provides a convenient mechanism for scientists to share data, visualizations and analytic algorithms via URLs. The Earth Engine data catalog contains a wide variety of popular, curated datasets, including the world's largest online collection of Landsat scenes (> 2.0M), numerous MODIS collections, and many vector-based data sets. The platform provides a uniform access mechanism to a variety of data types, independent of their bands, projection, bit-depth, resolution, etc..., facilitating easy multi-sensor analysis. Additionally, a user is able to add and curate their own data and collections. Using a just-in-time, distributed computation model, Earth Engine can rapidly process enormous quantities of geo-spatial data. All computation is performed lazily; nothing is computed until it's required either for output or as input to another step. This model allows real-time feedback and preview during algorithm development, supporting a rapid algorithm development, test, and improvement cycle that scales seamlessly to large-scale production data processing. Through integration with a variety of other services, Earth Engine is able to bring to bear considerable analytic and technical firepower in a transparent fashion, including: AI-based classification via integration with Google's machine learning infrastructure, publishing and distribution at Google scale through integration with the Google Maps API, Maps Engine and Google Earth, and support for in-the-field activities such as validation, ground-truthing, crowd-sourcing and citizen science though the Android Open Data Kit.

Gorelick, Noel

2013-04-01

318

On the near surface momentum balance in the Yucatán Channel  

Directory of Open Access Journals (Sweden)

Full Text Available The horizontal momentum balance in the upper layers of the Yucatán Channel is examined for a period of 22 months, from September 1999 to June 2001, using subsurface currents from ADCP measurements at eight moorings across the channel, pressure measurements from coastal pressure sensors on both sides of the channel, QuickSCAT winds and AVISO altimetry data. The averaged balance between Isla Mujeres, México, and Cabo San Antonio, Cuba, (across-channel axis) is basically geostrophic, but with contributions from ageostrophic terms, particularly friction against lower layers and to a lesser degree, the surface Ekman drift. Both the advective and the local acceleration terms appear unimportant in the side-to-side averaged balance. Interestingly, the averaged balance in along-channel axis is also mainly geostrophic; linear friction, Ekman drift, local acceleration and advective terms remain unimportant. An analysis of the balance from mooring to mooring across the channel indicates that in the region where the Yucatán current meanders, the advective terms with across-channel derivatives contribute significantly. The EOF modes of sea level anomalies from altimetry and the along-channel flow in the upper 90 m surface layer are correlated. Their two first modes are seemingly related to the transport fluctuations through the channel, but also to the along-channel pressure gradient and to the meandering of the Yucatán Current core, suggesting the presence of appreciable eddy-current interactions in the Channel.

M. Marín; J. Candela; J. Sheinbaum; J. Ochoa; A. Badan

2008-01-01

319

Birth of the Earth  

Science.gov (United States)

This lesson plan is part of the DiscoverySchool.com lesson plan library for grades 6-8. It focuses on the history of the Earth from 4.6 billion years ago to the present. Students look at different time periods and major events in the Earth's history, putting it all together in a classroom display. Included are objectives, materials, procedures, discussion questions, evaluation ideas, suggested readings, and vocabulary. There are videos available to order which complement this lesson, an audio-enhanced vocabulary list, and links to teaching tools for making custom quizzes, worksheets, puzzles and lesson plans.

320

Work-life balance  

Energy Technology Data Exchange (ETDEWEB)

Gay Renouf has opted for a work/life balance; with a chemistry degree she joined the Saskatchewan Research Council out of graduate school in 1986. She first worked on understanding surfactants in emulsions and then dealt more with petroleum engineering issues like pipeline specifications. She is looking at waterfloods in heavy and medium gravity pools and has discovered factors helping to produce heavy oil waterfloods. But all Renouf's life is not devoted to her work: she has been working part-time, spending her free time being a parent, training for marathons and being a running coach. Renouf believes that her passion for running is consistent with her work as a scientist.

Roche, Pat

2011-03-15

 
 
 
 
321

Balanced ventilation device  

UK PubMed Central (United Kingdom)

The utility model provides a balanced ventilation device, comprising an axial fan (5), wherein the lower end of the axial fan (5) is fixedly connected with the upper end of a fixing groove (3), a finned radiator (4) is connected in the fixing groove (3), the lower end of the fixing groove (3) is fixedly connected with a wind radiation plate (1), a wind radiation port (2) is fixedly connected in the wind radiation plate (1), thereby having simple structure, obtaining even hot blast in conveying process of the dried material, no needing to lengthen drying time, reducing drying cost, homogeneously distributting air-out intensity on the drying plane, and specially being suitable for food process.

YOULIANG FU; XIAORONG WANG

322

Energy and environmental balance  

Energy Technology Data Exchange (ETDEWEB)

Energy and environmental demands will require difficult choices during the rest of this century as competition for resources approaches ecological limitations. An historical review of energy demand traces the growth and impact of the urban-industrial revolution on environmental balance. Perceptions of the environment are changing in response to the effects of high energy growth and the recognition that nature must continue to be renewable and price is inadequate as an indication of environmental wealth. Policy debates that pit those who see man as a part of nature against those who grant man as having dominion over nature have been slow to develop either a grass-roots understanding or an institutional acknowledgement that the two issues are interrelated and require integrated policies. Warnings that open-ended growth will lead to a future doomsday have helped bring the issues to public attention. 99 references. (DCK)

Murphy, E.F.

1980-01-01

323

Ecologically Balanced Skill Acquisition  

UK PubMed Central (United Kingdom)

IntroductionThe field of developmental psychology puts forward the hypothesisthat constraints in the sensory system and biases inthe motor system may play an important adaptive role in theontogeny of cognition and action. Early limitations induce areduction of the complexity of the environmental informationthat impinges on a learning system during its interaction withthe environment, and therefore facilitate adaptivity. Later,these initial constraints are gradually released, resulting inchanges at the neural level, which in turn lead to new patternsof environmental interaction, and to a significant reductionof the difficulty of the problem of acquisition of new skills.This is directly related to the principle of ecological balance,which states that the agent's task environment, its sensory andmotor apparata (morphology), and its neural system have tobe well-matched in terms of their complexity. In particular,this principle can be applied to understanding why in a mecha

Max Lungarella; Luc Berthouze

324

Quasirandom Load Balancing  

CERN Document Server

We propose a simple distributed algorithm for balancing indivisible tokens on graphs. The algorithm is completely deterministic, though it tries to imitate (and enhance) a random algorithm by keeping the accumulated rounding errors as small as possible. Our new algorithm surprisingly closely approximates the idealized process (where the tokens are divisible) on important network topologies. On d-dimensional torus graphs with n nodes it deviates from the idealized process only by an additive constant. In contrast to that, the randomized rounding approach of Friedrich and Sauerwald (2009) can deviate up to Omega(polylog(n)) and the deterministic algorithm of Rabani, Sinclair and Wanka (1998) has a deviation of Omega(n^{1/d}). This makes our quasirandom algorithm the first known algorithm for this setting which is optimal both in time and achieved smoothness. We further show that also on the hypercube our algorithm has a smaller deviation from the idealized process than the previous algorithms.

Friedrich, Tobias; Sauerwald, Thomas

2010-01-01

325

Data needs for nutrient balances  

DEFF Research Database (Denmark)

One of the tools for evaluating the results of environmental action plans or EU directives related to nutrients in the agricultural sector is to follow the development of annually estimated nitrogen (N) and phosphorus (P) balances and surplus. Unlike greenhouse gas and ammonia emissions, countries are not required to report N and P balances for agriculture as part of any international conventions. As a consequence, there is no organisation equivalent to the Intergovernmental Panel on Climate Change (IPCC) or United Nations Economic Commission for Europe (UNECE) who has responsibility for standardising and improving the methodology to calculate such balances. However, Eurostat and OECD have jointly established a standard for using a gross N balances, and the soil N balance calculated by the CAPRI model has gained acceptance in European policymaking. It can be mentioned that the Task Force on Reactive Nitrogen (TFRN), established under Convention on Long-Range Transboundary Pollution (CLRTP), is currently establishing national N balances that include agriculture.

Vinther, Finn Pilgaard

2011-01-01

326

The role of the space station in earth science research  

International Nuclear Information System (INIS)

The International Space Station (ISS) has the potential to be a valuable platform for earth science research. By virtue of its being in a mid-inclination orbit (51.5 deg.), ISS provides the opportunity for nadir viewing of nearly 3/4 of the Earth's surface, and allows viewing to high latitudes if limb-emission or occultation viewing techniques are used. ISS also provides the opportunity for viewing the Earth under a range of lighting conditions, unlike the polar sun-synchronous satellites that are used for many earth observing programs. The ISS is expected to have ample power and data handling capability to support Earth-viewing instruments, provide opportunities for external mounting and retrieval of instruments, and be in place for a sufficiently long period that long-term data records can be obtained. On the other hand, there are several questions related to contamination, orbital variations, pointing knowledge and stability, and viewing that are of concern in consideration of ISS for earth science applications. The existence of an optical quality window (the Window Observational Research Facility, or WORF), also provides the opportunity for Earth observations from inside the pressurized part of ISS. Current plans by NASA for earth science research from ISS are built around the Stratospheric Aerosol and Gas Experiment (SAGE III) instrument, planned for launch in 2002.

2054-01-00

327

Near-earth Thin Current Sheets and Birkeland Currents during Substorm Growth Phase  

Energy Technology Data Exchange (ETDEWEB)

Two important phenomena observed during the magnetospheric substorm growth phase are modeled: the formation of a near-Earth (|X| {approx} 9 R{sub E}) thin cross-tail current sheet, as well as the equatorward shift of the ionospheric Birkeland currents. Our study is performed by solving the 3-D force-balance equation with realistic boundary conditions and pressure distributions. The results show a cross-tail current sheet with large current (J{sub {phi}} {approx} 10 nA/m{sup 2}) and very high plasma {beta} ({beta} {approx} 40) between 7 and 10 R{sub E}. The obtained region-1 and region-2 Birkeland currents, formed on closed field lines due to pressure gradients, move equatorward and become more intense (J{sub {parallel}max} {approx} 3 {micro}A/m{sup 2}) compared to quiet times. Both results are in agreement with substorm growth phase observations. Our results also predict that the cross-tail current sheet maps into the ionosphere in the transition region between the region-1 and region-2 currents.

Sorin Zaharia; C.Z. Cheng

2003-04-30

328

Mission to Planet Earth - The Earth Observing System  

Energy Technology Data Exchange (ETDEWEB)

The Earth Observing System (EOS) is a major component of NASA's Mission to Planet Earth initiative. It seeks to achieve a comprehensive understanding of the earth as a system, including its various components (solid earth, atmosphere, hydrosphere, and biosphere) and its various processes (hydrologic cycle, biogeochemical cycles, and climatic processes). This is to be achieved by space-based remote sensing, using a variety of instrumentation and observing techniques, operating simultaneously, and providing continuous and complete global coverage over a long time period. A few of the investigations to be carried out with EOS, in areas of (1) imagery of the earth from space, and (2) investigations of the earth's radiation budget are described. EOS is expected to make major contributions to the basic earth sciences (geology, meteorology, etc.), but its results also will have important immediate or near-term practical applications which will improve the quality of life on earth. 18 refs.

Carruthers, G.R.; Lee, R.B. III (E. O. Hulburt Center for Space Research, Washington, DC (USA) NASA, Langley Research Center, Hampton, VA (USA))

1989-01-01

329

Deuterium inventory in Tore Supra: Coupled carbon-deuterium balance  

Science.gov (United States)

This paper presents an analysis of the carbon-deuterium circulation and the resulting balance in Tore Supra over the period 2002-2007. Carbon balance combines the estimation of carbon gross erosion from spectroscopy, net erosion and deposition using confocal microscopy, lock-in thermography and SEM, and a measure of the amount of deposits collected in the vacuum chamber. Fuel retention is determined from post-mortem (PM) analyses and gas balance (GB) measurements. Special attention was paid to the deuterium outgassed during the nights and weekends of the experimental campaign (vessel under vacuum, Plasma Facing Components at 120 °C) and during vents (vessel at atmospheric pressure, PFCs at room temperature). It is shown that this outgassing is the main process reconciling the PM and GB estimations of fuel retention, closing the coupled carbon-deuterium balance. In particular, it explains why the deuterium concentration in deposits decreases with increasing depth.

Pégourié, B.; Panayotis, S.; Languille, P.; Martin, C.; Dittmar, T.; Gauthier, E.; Hatchressian, J.-C.; Pascal, J.-Y.; Roubin, P.; Ruffe, R.; Tsitrone, E.; Vartanian, S.; Wang, H.; Beauté, A.; Bouvet, J.; Brosset, C.; Bucalossi, J.; Cabié, M.; Caprin, E.; Courtois, X.; Dachicourt, R.; Delchambre, E.; Dominici, C.; Douai, D.; Ekedahl, A.; Gunn, J. P.; Hakola, A.; Jacob, W.; Khodja, H.; Likonen, J.; Linez, F.; Litnovsky, A.; Marandet, Y.; Markelj, S.; Martinez, A.; Mayer, M.; Meyer, O.; Monier-Garbet, P.; Moreau, P.; Negrier, V.; Oddon, P.; Pardanaud, C.; Pasquet, B.; Pelicon, P.; Petersson, P.; Philipps, V.; Possnert, G.; Reiter, D.; Roth, J.; Roure, I.; Rubel, M.; Saint-Laurent, F.; Samaille, F.; Vavpeti?, P.

2013-07-01

330

Self-balancing drilling assembly and apparatus  

Energy Technology Data Exchange (ETDEWEB)

This patent describes a self-balancing apparatus for automatically compensating certain imbalances which tend to cause vibrations in a rotating drill bit. It comprises: a support body including two ends and first and second circular races defined circumferentially around said support body. The first race disposed near one end of said support body and said second race disposed nearer the other end of said support body; a fluid received in said first race; a fluid received in said second race; pressure compensating means for compensating for pressure differentials between said fluids and a fluid external to said support body; a first plurality of movable balls or rollers disposed in said first race; a second plurality of movable balls or rollers disposed in said second race; a first sleeve receiving the portion of said support body where said first race is defined; and a second sleeve receiving the portion of said support body where said second race is defined.

Beynet, P.A.; Brett, J.F.; Warren, T.M.

1990-03-06

331

Accretion disc origin of the Earth's water.  

UK PubMed Central (United Kingdom)

Earth's water is conventionally believed to be delivered by comets or wet asteroids after the Earth formed. However, their elemental and isotopic properties are inconsistent with those of the Earth. It was thus proposed that water was introduced by adsorption onto grains in the accretion disc prior to planetary growth, with bonding energies so high as to be stable under high-temperature conditions. Here, we show both by laboratory experiments and numerical simulations that water adsorbs dissociatively on the olivine {100} surface at the temperature (approx. 500-1500 K) and water pressure (approx. 10?? bar) expected for the accretion disc, leaving an OH adlayer that is stable at least up to 900 K. This may result in the formation of many Earth oceans, provided that a viable mechanism to produce water from hydroxyl exists. This adsorption process must occur in all disc environments around young stars. The inevitable conclusion is that water should be prevalent on terrestrial planets in the habitable zone around other stars.

Vattuone L; Smerieri M; Savio L; Asaduzzaman AM; Muralidharan K; Drake MJ; Rocca M

2013-07-01

332

Earth in the Universe  

Science.gov (United States)

This self-contained module on the Earth and planetary science includes a range of fun activities that students can perform in the classroom and at home with family members. The activities impart important concepts such as observation, identification, measurement, and differentiation.

Science, Houghton M.

333

Doklady Earth Sciences Doklady??????  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Doklady Earth Sciences is a journal of the Presidium of the Russian Academy of Sciences. It contains English translations of papers published in Doklady Akademii Nauk (Proceedings of the Russian Academy of Sciences), which was founded in 1933 and is published 36 times a year.

334

Earth flyby anomalies  

Energy Technology Data Exchange (ETDEWEB)

In the planet-centric system, a spacecraft should have the same initial and final energies, even though its energy and angular momentum will change in the barycenter of the solar system. However, without explanation, a number of earth flybys have yielded small energy changes.

Nieto, Michael Martin [Los Alamos National Laboratory; Anderson, John D [PROPULSION LAB.

2009-01-01

335

Is earth burning  

Energy Technology Data Exchange (ETDEWEB)

A review of the potential effects of the greenhouse effect and ozone layer hole on the earth ecological system is presented: sea level rise, coastal land salination, highly strong cyclones, temperate zone aridity, engulfed islands, etc. and more than 300 millions of environment refugees. Several remedies are proposed and analyzed and among them solar energy, a Marshall Plan for energy conservation, etc.

Philibert, C.

1990-03-01

336

"Galileo Calling Earth..."  

Science.gov (United States)

This guide presents an activity for helping students understand how data from the Galileo spacecraft is sent to scientists on earth. Students are asked to learn about the concepts of bit-rate and resolution and apply them to the interpretation of images from the Galileo Orbiter. (WRM)

National Aeronautics and Space Administration, Washington, DC.

337

Near Earth Objects  

DEFF Research Database (Denmark)

The word planet comes from Greek planetes, wanderers, because the planets appear to wander across the celestial sphere, contrary to the fixed stars. This thesis presents several methods for using this motion to distinguish between stars and solar system objects in order to detect and track NEOs, Near Earth Objects: Asteroids and comets following paths that bring them near the Earth. NEOs have collided with the Earth since its formation, some causing local devastation, some causing global climate changes, yet the threat from a collision with a near Earth object has only recently been recognised and accepted. The European Space Agency mission Gaia is a proposed space observatory, designed to perform a highly accurate census of our galaxy, the Milky Way, and beyond. Through accurate measurement of star positions, Gaia is expected to discover thousands of extra-solar planets and follow the bending of starlight by the Sun, and therefore directly observe the structure of space-time. This thesis explores several aspects of the observation of NEOs with Gaia, emphasising detection of NEOs and the quality of orbits computed from Gaia observations. The main contribution is the work on motion detection, comprising a comparative survey of five different motion detection tests, one of which is proved to be optimal among all translation invariant and symmetric tests.

Wolff, Stefan

2006-01-01

338

Energy conservation in the earth's crust and climate change.  

Science.gov (United States)

Among various matters which make up the earth's crust, the thermal conductivity of coal, oil, and oil-gas, which are formed over a long period of geological time, is extremely low. This is significant to prevent transferring the internal heat of the earth to the thermal insulation of the surface, cooling the surface of the earth, stimulating biological evolution, and maintaining natural ecological balance as well. Fossil energy is thermal insulating layer in the earth's crust. Just like the function of the thermal isolation of subcutaneous fatty tissue under the dermis of human skin, it keeps the internal heat within the organism so it won't be transferred to the skin's surface and be lost maintaining body temperature at low temperatures. Coal, oil, oil-gas, and fat belong to the same hydrocarbons, and the functions of their thermal insulation are exactly the same. That is to say, coal, oil, and oil-gas are just like the earth's "subcutaneous fatty tissue" and objectively formed the insulation protection on earth's surface. This paper argues that the human large-scale extraction of fossil energy leads to damage of the earth's crust heat-resistant sealing, increasing terrestrial heat flow, or the heat flow as it is called, transferring the internal heat of the earth to Earth's surface excessively, and causing geotemperature and sea temperature to rise, thus giving rise to global warming. The reason for climate warming is not due to the expansion of greenhouse gases but to the wide exploitation of fossil energy, which destroyed the heat insulation of the earth's crust, making more heat from the interior of the earth be released to the atmosphere. Based on the energy conservation principle, the measurement of the increase of the average global temperature that was caused by the increase of terrestrial heat flow since the Industrial Revolution is consistent with practical data. Implications: This paper illustrates "pathogenesis" of climate change using medical knowledge. The mathematical verification is based on the principle of energy conservation. The central idea or clou in this paper is that fossil energy is a thermal insulating layer in the earth's crust, the thermal insulating layer was destroyed after human large-scale mining of fossil energy, and the internal heat of the earth was excessively released to the surface so as to cause climate change. PMID:23472299

Mu, Yao; Mu, Xinzhi

2013-02-01

339

Energy conservation in the earth's crust and climate change.  

UK PubMed Central (United Kingdom)

Among various matters which make up the earth's crust, the thermal conductivity of coal, oil, and oil-gas, which are formed over a long period of geological time, is extremely low. This is significant to prevent transferring the internal heat of the earth to the thermal insulation of the surface, cooling the surface of the earth, stimulating biological evolution, and maintaining natural ecological balance as well. Fossil energy is thermal insulating layer in the earth's crust. Just like the function of the thermal isolation of subcutaneous fatty tissue under the dermis of human skin, it keeps the internal heat within the organism so it won't be transferred to the skin's surface and be lost maintaining body temperature at low temperatures. Coal, oil, oil-gas, and fat belong to the same hydrocarbons, and the functions of their thermal insulation are exactly the same. That is to say, coal, oil, and oil-gas are just like the earth's "subcutaneous fatty tissue" and objectively formed the insulation protection on earth's surface. This paper argues that the human large-scale extraction of fossil energy leads to damage of the earth's crust heat-resistant sealing, increasing terrestrial heat flow, or the heat flow as it is called, transferring the internal heat of the earth to Earth's surface excessively, and causing geotemperature and sea temperature to rise, thus giving rise to global warming. The reason for climate warming is not due to the expansion of greenhouse gases but to the wide exploitation of fossil energy, which destroyed the heat insulation of the earth's crust, making more heat from the interior of the earth be released to the atmosphere. Based on the energy conservation principle, the measurement of the increase of the average global temperature that was caused by the increase of terrestrial heat flow since the Industrial Revolution is consistent with practical data. Implications: This paper illustrates "pathogenesis" of climate change using medical knowledge. The mathematical verification is based on the principle of energy conservation. The central idea or clou in this paper is that fossil energy is a thermal insulating layer in the earth's crust, the thermal insulating layer was destroyed after human large-scale mining of fossil energy, and the internal heat of the earth was excessively released to the surface so as to cause climate change.

Mu Y; Mu X

2013-02-01

340

Cloud-radiation interaction and the earth's climate: Relevance to the climate of the Arctic  

Energy Technology Data Exchange (ETDEWEB)

The influence on the energy balance of the earth's climate system is reviewed and is based on recent satellite observations of the Earth's Radiation Budget (ERB) and other satellite-derived cloud information. The special difficulties that polar cloudiness poses in analysis of ERB data are discussed. The role of arctic cloudiness on the snow-ice albedo feedback is examined and the possible influence of this feedback to global cloudiness and thus to the radiation balance on the earth are explored.

Stephens, G.L.

1992-03-01

 
 
 
 
341

The earth dynamic system: the earth rotation vs mantle convection  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The earth dynamic system is one of the key scientific questions on the earth science. The thermodynamic behavior and gravity force of the earth and the rheology nature of the mantle prove that mantle convection is the main power source leading the lithosphere to break and move. Yet the directivity o...

Shuping Chen

342

Earth Observations: Pattern Recognition of the Earth System  

Science.gov (United States)

Earth Observation is an activity where students observe and patterns in datasets of the different Earth spheres. Correlations between datasets are examined to stimulate student thinking of the interrelations in the Earth system. This activity is connect to process and concepts covered later in the class.

Nyman, Matthew

343

Análise de fases por difração de raios X de WC-10%Co dopado com terras-raras obtido sob alta pressão/ Phase analysis by x-ray diffraction on the WC-10Co doped with rare-earth elements obtained under high pressure  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese O carbeto cementado WC-Co também denominado de metal duro é um material de grande importância tecnológica produzido por metalurgia do pó através de sinterização por fase líquida, partindo-se da mistura dos pós de carbeto de tungstênio (WC) e de cobalto (Co) em moinho convencional. Entretanto, para obtenção de metal duro com maior capacidade (produtividade, vida útil, etc.), uma nova rota alternativa de metalurgia do pó denominada de altas pressões e altas (more) temperaturas vem sendo utilizada para produção destes materiais com resultados promissores. O presente trabalho tem como objetivo principal a análise de fases de WC-10Co dopado com terras-raras (La2O3, CeO2e Y2O3) preparadas sob condições de alta pressão. Esta liga de metal duro é um exemplo de material compósito largamente utilizado como ferramenta de corte e operações de usinagem em geral. Foram preparadas diversas misturas de WC-10Co contendo até 2 % em peso de terra-rara (La2O3, CeO2e Y2O3) da fase cobalto. Os pós previamente misturados foram compactados numa matriz cilíndrica (? = 7 mm) a uma pressão de 800 MPa e sinterizados a 1400 ºC durante 40 s sob alta pressão de 5,5 GPa. Os compósitos produzidos foram caracterizados por difração de raios X para identificação de fases cristalinas presentes. Além disso, foi feita análise comparativa entre o carbeto isento de terra-rara (amostras de referência) e carbetos dopados com elementos de terra-rara (La2O3, CeO2, e Y2O3). Para as condições estudadas os resultados mostraram que durante o processo de sinterização ocorreu à formação, mesmo que em pequenas quantidades, das fases Co3W3C2 e ? (carbeto tipo ?) nas peças de metal duro estudadas. Abstract in english The WC-Co cemented carbide also called hardmetal is a material of great technological importance, currently produced by powder metallurgy by liquid phase sintering, starting from the mixture of powdered tungsten carbide (WC) and cobalt (Co) using conventional mill. Seeking to obtain materials with higher capacity (productivity, life, etc.), an alternative route for powder metallurgy called High Pressure High Temperature (HPHT) has been used for the production of these mat (more) erials with promising results. The main aim of this work is the phases analysis of the WC-10Co doped with rare-earths (La2O3, CeO2,and Y2O3) obtained under high pressure. This hardmetal alloy is an example of the composite material widely used as cutting tool and machining processes in general. Several WC-10Co mixtures containing up to 2 wt % La2O3,CeO2and Y2O3 of the cobalt phase were prepared. The mixed powders were pressed at 800 MPa in a cylindrical matrix (? = 7 mm) and sintered at 1400ºC during 40 s under high pressure (5.5 GPa). The identification of the crystalline phases was done by X-ray diffraction. In addition, comparative analysis between the free rare-earth and doped with rare-earths elements (La2O3, CeO2 and Y2O3) carbides was done. The results showed that, within the conditions studied during the sintering process, formation, even, small amounts, of the phases Co3W3C2 and ? (? carbide type) were observed in the carbide pieces studied.

Marques, C. M. F. G.; Bobrovnitchii, G. S.; Holanda, J. N. F.

2013-01-01

344

Pressure losses in pneumatic transport  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A model is derived to calculate the pressure losses originating from the dilute phase pneumatic transport of coarse particles in the horizontal stationary flow regime. The model is based on the balance of drag forces and frictional forces acting on the particles during pneumatic transport. The parti...

Ottjes, J.A.

345

Rare earth base superconducting composition  

International Nuclear Information System (INIS)

A superconductin mixed valence copper oxide with a perowskite structure is claimed. It comprises a valence 4 rare earth (Ce or Pr), an alkaline earth metal (Sr or Ba) and thallium. Chemical composition is given and synthesis is described

1989-07-11

346

The Earth's atmosphere. Its physics and dynamics  

Energy Technology Data Exchange (ETDEWEB)

This book covers a wide area of the atmospheric science, focusing particularly on those physical and dynamical aspects of our environment which tend to create heat sources and sinks in the earth-atmosphere system and which it seeks to balance through circulation at different time and space scales. The processes of heat transfer in the atmosphere and ocean by general circulation and by waves and oscillations are discussed in detail. The heat balance of the atmosphere is considered, after taking into consideration the role of various types of greenhouse gases that may be present. In this context, the publication of the book will be very timely and will be welcomed by all those interested in knowing more about our atmosphere and the way it works, especially with regard to the contentious issue of global warming by greenhouse gases released by human activities on earth. Starting with the origin, composition and structure of the atmosphere, the physics part deals with the laws of heat and thermodynamics of dry and moist air, water vapor and its transformation into different phases and formation of cloud and rain under different stability conditions, solar and terrestrial radiation and their impact on the gaseous envelope in different layers of the atmosphere which create sources and sinks in different parts of the atmosphere especially in its boundary layers. The dynamics part highlights the various types of motion systems including the general circulation of waves and oscillations which create the heat balance in the earth-atmosphere system. (orig.)

Saha, Kshudiram

2008-07-01

347

Galactic cosmic ray clouds effect and bifurcation model of the Earth global climate  

International Nuclear Information System (INIS)

[en] The possible physical linkage between the cosmic rays - cloud and indirect aerosol effects is discussed using the analysis of the first indirect aerosol effect (Twomey effect) and its experimental representation as the dependence of mean cloud droplet effective radius versus aerosol index defining the column aerosol number. It is shown that the main kinetic equation of Earth climate energy-balance model is described by the bifurcation equation (relative to the surface temperature of the Earth) in the form of fold catastrophe with two controlling parameters defining the variations of insolation and Earth magnetic field (or cosmic rays intensity in the atmosphere) respectively. The results of comparative analysis on the time-dependent solution (time series of global palaeotempreture) of Earth climate energy-balance model taking into account nontrivial role of galactic cosmic rays and the known experimental data on the palaeotemperature from the EPICA Dome C and Vostok ice core are presented. (authors)

2008-01-01

348

Testing, Adjusting and Balancing for the HVAC of Advanced Fuel Science Building  

International Nuclear Information System (INIS)

[en] To maintain the optimum condition of Advanced Fuel Science Building in KAERI, this report is described TAB(Testing, Adjusting and Balancing) for the HVAC of Advanced Fuel Science Building. The main topics of this report are testing, adjusting and balancing as follows for: Motor, Airflow, Temperature and Humidity, Differential Pressure

2005-01-01

349

Effect of self-consistent magnetic field on plasma sheet penetration to the inner magnetosphere: Rice convection model simulations combined with modified Dungey force-balanced magnetic field solver  

Science.gov (United States)

Transport of plasma sheet particles into the inner magnetosphere is crucial to the development of the region 2 (R2) field-aligned current system (FAC), which results in the shielding of the penetration electric field and the formation of subauroral polarization streams (SAPS) and the Harang reversal, phenomena closely associated with storms and substorms. In addition to the electric field, this transport is also strongly affected by the magnetic field, which changes with plasma pressure and is distinctly different from the dipole field in the inner plasma sheet. To determine the feedback of force-balanced magnetic field to the transport, we have integrated the Rice convection model (RCM) with a modified Dungey magnetic field solver to obtain the required force balance in the equatorial plane. Comparing our results with those from a RCM run using a T96 magnetic field, we find that transport under a force-balanced magnetic field results in weaker pressure gradients and thus weaker R2 FAC in the near-Earth region and weaker shielding of the penetration electric field. As a result, plasma sheet protons and electrons penetrate farther earthward, and their inner edges become closer together and more azimuthally symmetric than in the T96 case. The Harang reversal extends farther dawnward, and the SAPS become more confined in radial and latitudinal extents. The magnitudes of azimuthal pressure gradient, the inner edges of thermal protons and electrons, the latitudinal range of the Harang reversal, and the radial and latitudinal widths of the SAPS from the force-balanced run are found to be more consistent with observations.

Gkioulidou, Matina; Wang, Chih-Ping; Lyons, Larry R.

2011-12-01

350

Russia - Nato. The military balance  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This project aims to explain how the military balancing of Russia against NATO can be explained from a neoclassical realist framework. The project consists in three analytical parts of respectively, 1: The military capabilities balance between NATO and Russia; 2: How the international system puts pr...

Daugaard, Søren Bech; Jacobsen, Karen Vestergård; Aigro, Signe; Skarequist, Anne

351

Journal of Earth System Science ????????  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Published bimonthly, the Journal of Earth System Science is highly interdisciplinary and publishes high-quality research - new data, ideas, and conceptual advances - in Earth System Science in its broadest sense. This includes the solid earth, the atmosphere, the hydrosphere, and the biospher...

352

The Earth-Moon Barycenter  

Science.gov (United States)

The representation depicts the moon's orbit around the Earth by marking days along the orbital path. The resource also shows the gravitational center of the moon-Earth system and the gravitational center of the Earth-moon system, indicating the direction toward the sun.

353

Interim balance: Ecology  

International Nuclear Information System (INIS)

Subjects: The ecology problem - world wide. Sectoral balances: The examples of energy, transportation, chemistry, agriculture and food industry, water supply. Destruction of nature and human discord. Conservatives in our political parties and their views on environmental protection. Alliance between reds and 'greens', integration between reds and greens. The Rhine initiative. Lead respects no borders, experiences of citizens' action groups in Lothringia and the Saar district. International airport Munich-II/comments by a protestant. 'Give priority to life'/A hearing on environmental protection. 4:96 - 'greens' in the Bremen Senate. Policy in a hard-hearing world/psychology of citizens' action groups. Critical ecological research and scientific establishment. Full productivity and ecology. The deluge to follow/Hints on how to build an ark. Symbiosis is more than coexistence/Ecologists' social theory. Throwing in two hundred elementary particles/on the way to an ecological concept of science. Scientific journals. Alternative literature. Teaching model for a teaching subject 'ecology'. (orig.)

1981-01-01

354

The right balance  

CERN Multimedia

Over the course of her career as a physicist, Felicitas Pauss, currently responsible for CERN's External Relations, has often been the sole woman in an environment dominated by men. While she freely admits that being a woman physicist can have as many advantages as disadvantages, she thinks the best strategy is to maintain the right balance.   From a very early age, Felicitas Pauss always wanted to be involved in projects that interested and fascinated her. That's how she came to study physics. When she was a first-year university student in Austria in 1970, it was still fairly uncommon for women to go into physics research. "I grew up in Salzburg with a background in music. At that time, it was certainly considered more ‘normal’ for a woman to study music than to do research in physics. But already in high school I was interested in physics and technical instruments and wanted to know how things work and what they are made of”. At the beginning of her care...

CERN Bulletin

2010-01-01

355

Par Pond water balance  

Energy Technology Data Exchange (ETDEWEB)

A water budget for the Par Pond hydrologic system was established in order to estimate the rate of groundwater influx to Par Pond. This estimate will be used in modeling exercises to predict Par Pond reservoir elevation and spillway discharge in the scenario where Savannah River water is no longer pumped and discharged into Par Pond. The principal of conservation of mass was used to develop the water budget, where water inflow was set equal to water outflow. Components of the water budget were identified, and the flux associated with each was determined. The water budget was considered balanced when inflow and outflow summed to zero. The results of this study suggest that Par Pond gains water from the groundwater system in the upper reaches of the reservoir, but looses water to the groundwater system near the dam. The rate of flux of groundwater from the water table aquifer into Par Pond was determined to be 13 cfs. The rate of flux from Par Pond to the water table aquifer near the dam was determined to be 7 cfs.

Hiergesell, R.A.; Dixon, K.L.

1996-06-01

356

Paul Collier : Balancing beams  

CERN Multimedia

As former head of AB Operations, Paul Collier and his group were in the ‘cockpit’ for the LHC’s maiden voyage - piloting the first beam around the ring. But now, as Head of the Beams Department, he will need his feet firmly on the ground in order to balance all the beam activities at CERN. "As Department Head, I’ll have less direct contact with the machines," Collier says with a hint of regret. "I’ll still obviously be very involved, but they won’t actually let me loose in front of the keyboard anymore!" As the new Head of the BE Department, Collier will be in charge of nearly 400 people, and will oversee all the beam activities, including the preparations for the longest period of beam operation in the history of CERN. In the new organization, the BE, TE and EN Departments have been grouped together in the Accelerator and Technology Sector. "‘Partnership’ is a key word for the three departments," says Collier. "The n...

2009-01-01

357

Par Pond water balance  

International Nuclear Information System (INIS)

A water budget for the Par Pond hydrologic system was established in order to estimate the rate of groundwater influx to Par Pond. This estimate will be used in modeling exercises to predict Par Pond reservoir elevation and spillway discharge in the scenario where Savannah River water is no longer pumped and discharged into Par Pond. The principal of conservation of mass was used to develop the water budget, where water inflow was set equal to water outflow. Components of the water budget were identified, and the flux associated with each was determined. The water budget was considered balanced when inflow and outflow summed to zero. The results of this study suggest that Par Pond gains water from the groundwater system in the upper reaches of the reservoir, but looses water to the groundwater system near the dam. The rate of flux of groundwater from the water table aquifer into Par Pond was determined to be 13 cfs. The rate of flux from Par Pond to the water table aquifer near the dam was determined to be 7 cfs.

1996-01-01

358

BALANCE AND FORCE PLATE  

UK PubMed Central (United Kingdom)

A balance and load defining plate (1) comprising four sides that extend generally verticalin relation to one another, said sides including a bottom plate (2) and a covermember (8) fastened to the bottom plate (2) for recording movement in three directionsof something placed on the cover member (8) and further including recording devicesplaced within the plate (1). The invention is characterised in that said devicescomprise vertical load cells (3) which are placed in mutually spaced relationshipon the bottom plate (2) and which are adapted to record movement in a first direction(z); in that said devices also include horizontal load cells (4) which are placedin mutually spaced relationship on the bottom plate (2); in that a bias-free circularcomponent (5) is inscribed centrally between said horizontal load cells (4);in that the circular component (5) is fastened to the cover member (8) on a sidethat faces towards the bottom plate (2); and in that horizontal load cells (4)and the central circular component (5) are together adapted to record movementin a second direction (x) and a third direction (y) where the first direction (z),the second direction (x) and the third direction (y) are mutually perpendicularto one another.

ANDERSSON Stefan

359

Distributed Selfish Load Balancing  

CERN Multimedia

Suppose that a set of m tasks are to be shared as equally as possible amongst a set of n resources. A game-theoretic mechanism to find a suitable allocation is to associate each task with a ``selfish agent'', and require each agent to select a resource, with the cost of a resource being the number of agents to select it. Agents would then be expected to migrate from overloaded to underloaded resources, until the allocation becomes balanced. Recent work has studied the question of how this can take place within a distributed setting in which agents migrate selfishly without any centralized control. In this paper we discuss a natural protocol for the agents which combines the following desirable features: It can be implemented in a strongly distributed setting, uses no central control, and has good convergence properties. We show using a martingale technique that the process converges in expected time O(\\log\\log m + n^4). We also give a lower bound of \\Omega(\\max{\\log\\log m, n}) for the convergence time, as wel...

Berenbrink, P; Goldberg, L A; Goldberg, P; Hu, Z; Martin, R; Berenbrink, Petra; Friedetzky, Tom; Goldberg, Leslie Ann; Goldberg, Paul; Hu, Zengjian; Martin, Russell

2005-01-01

360

Leg preference and interlateral asymmetry of balance stability in soccer players.  

UK PubMed Central (United Kingdom)

To examine the effect of long lasting practice on pedal behavior in sport, we compared experienced adult soccer players and nonsoccer players on leg preference in motor tasks requiring general mobilization, soccer related mobilization, and body balance stabilization. We also evaluated performance asymmetry between the right and left legs in static and dynamic unipedal body balance, based on center of pressure displacement, and correlated that with leg preference in balance stabilization tasks. Results revealed (a) a distinct leg preference between mobilization and stabilization tasks, which were significantly different between players and nonplayers, (b) similar balance stability between the right and left legs, (c) greater stability of experienced players compared with nonplayers in static and dynamic balance, and (d) absence of a significant leg preference correlation with interlateral balance asymmetry. These results suggest an effect of extensive soccer skill practice on establishing leg preference for specific mobilization tasks and overall balance control.

Teixeira LA; de Oliveira DL; Romano RG; Correa SC

2011-03-01

 
 
 
 
361

Earth hummocks in the regions of Vlasina and Krajište, Southern Serbia  

Directory of Open Access Journals (Sweden)

Full Text Available The paper determines genetic factors of earth hummocks that are found below the lower limit of the periglacial processes. This issue was analyzed in the area of Vlasina and Krajište, where seven localities with earth hummocks and one locality with palsa mounds. Genetic factors have been classified into two groups: inherited factors (geological composition, temperature fluctuations, vegetation, hydrogeological regime) and additional factors, such as human activities which led to changes of ecological balance and microclimatic characteristics.

Miloševi? Marko V.; Milivojevi? Milovan; ?ali? Jelena

2007-01-01

362

Gun firing system using fluid filled pressure balance tubing  

Energy Technology Data Exchange (ETDEWEB)

This patent describes a tool string adapted for use in completing a payzone intersected by a borehole, the tool string including a perforating gun supported by a tubing string. The gun includes a firing head at the upper end thereof actuable by a gun firing means run downhole through the tubing string into contact therewith. An apparatus is described comprising: a chamber above the gun, the firing head being in communication with the chamber; closure means comprising a piston having a longitudinal passageway extending therethrough received within the chamber and in slidable sealed relationship with the wall thereof. The piston further includes frangible disk means closing the passageway, the closure means being disposed proximate the upper end of the chamber and isolating the firing head from the interior of the tubing string thereabove; and means associated with the gun firing means for penetrating the closure means and thereafter actuating the firing head, firing the gun to perforate the wall of the borehole and intersected payzone.

Vann, R.R.; Brieger, E.F.; George, F.R.; Colle, E.A. Jr.; Jones, H.B.

1987-01-13

363

Earth{'}s Polar Magnetosphere and Aurora  

Science.gov (United States)

High-latitude convection, magnetic field-aligned currents and particle precipitation are powered at Earth primarily by the dynamo action of the solar wind flowing across polar geomagnetic field lines. The resulting auroral luminosity provides a sensitive diagnostic of large-scale magnetospheric dynamics and structure -- features that are specific to magnetospheric processes driven by a solar wind-magnetosphere interation. At the same time, the physical processes that enable aurora, e.g., the formation of parallel electric fields and auroral particle acceleration, time-variable transmission of electromagnetic power along magnetic field lines by Alfvén waves, and dynamic structuring of aurora resulting from impedance mismatch between the magnetospheric dynamo and ionospheric load, do not necessarily depend on the nature of either the dynamo or the load. This paper will review the large-scale electrodynamics of the terrestrial polar magnetosphere and the plasma physics and magnetohydrodynamics that enable high-latitude terrestrial aurora. It will also attempt to distinguish between terrestrial-specific processes and ones that are also likely to be operative in the Jovian polar magnetosphere and aurora.

Lotko, W.

2004-12-01

364

Heat-pipe Earth.  

UK PubMed Central (United Kingdom)

The heat transport and lithospheric dynamics of early Earth are currently explained by plate tectonic and vertical tectonic models, but these do not offer a global synthesis consistent with the geologic record. Here we use numerical simulations and comparison with the geologic record to explore a heat-pipe model in which volcanism dominates surface heat transport. These simulations indicate that a cold and thick lithosphere developed as a result of frequent volcanic eruptions that advected surface materials downwards. Declining heat sources over time led to an abrupt transition to plate tectonics. Consistent with model predictions, the geologic record shows rapid volcanic resurfacing, contractional deformation, a low geothermal gradient across the bulk of the lithosphere and a rapid decrease in heat-pipe volcanism after initiation of plate tectonics. The heat-pipe Earth model therefore offers a coherent geodynamic framework in which to explore the evolution of our planet before the onset of plate tectonics.

Moore WB; Webb AA

2013-09-01

365

Rare earth thermoelectrics  

Energy Technology Data Exchange (ETDEWEB)

The author reviews the thermoelectric properties of metallic compounds which contain rare-earth atoms. They are the group of metals with the largest value ever reported of the Seebeck coefficient. An increase by 50% of the Seebeck would make these compounds useful for thermoelectric devices. The largest Seebeck coefficient is found for compounds of cerium (e.g., CePd{sub 3}) and ytterbium (e.g., YbAl{sub 3}). Theoretical predictions are in agreement with the maximum observed Seebeck. The author discusses the theoretical model which has been used to calculate the Seebeck coefficient. He is solving this model for other configurations (4f){sup n} of rare-earth ground states.

Mahan, G.D.

1997-09-01

366

Life Before Earth  

CERN Document Server

An extrapolation of the genetic complexity of organisms to earlier times suggests that life began before the Earth was formed. Life may have started from systems with single heritable elements that are functionally equivalent to a nucleotide. The genetic complexity, roughly measured by the number of non-redundant functional nucleotides, is expected to have grown exponentially due to several positive feedback factors: gene cooperation, duplication of genes with their subsequent specialization, and emergence of novel functional niches associated with existing genes. Linear regression of genetic complexity on a log scale extrapolated back to just one base pair suggests the time of the origin of life 9.7 billion years ago. This cosmic time scale for the evolution of life has important consequences: life took ca. 5 billion years to reach the complexity of bacteria; the environments in which life originated and evolved to the prokaryote stage may have been quite different from those envisaged on Earth; there was no...

Sharov, Alexei A

2013-01-01

367

Heat-pipe Earth.  

Science.gov (United States)

The heat transport and lithospheric dynamics of early Earth are currently explained by plate tectonic and vertical tectonic models, but these do not offer a global synthesis consistent with the geologic record. Here we use numerical simulations and comparison with the geologic record to explore a heat-pipe model in which volcanism dominates surface heat transport. These simulations indicate that a cold and thick lithosphere developed as a result of frequent volcanic eruptions that advected surface materials downwards. Declining heat sources over time led to an abrupt transition to plate tectonics. Consistent with model predictions, the geologic record shows rapid volcanic resurfacing, contractional deformation, a low geothermal gradient across the bulk of the lithosphere and a rapid decrease in heat-pipe volcanism after initiation of plate tectonics. The heat-pipe Earth model therefore offers a coherent geodynamic framework in which to explore the evolution of our planet before the onset of plate tectonics. PMID:24067709

Moore, William B; Webb, A Alexander G

2013-09-26

368

The rigidity of the Earth’s inner core  

Directory of Open Access Journals (Sweden)

Full Text Available The evidence for the existence of significant rigidity in the Earth's inner core is summarised and discussed in the light of recent work. Quantum-mechanical calculations, based on a Thomas-Fermi-Dirac model, suggest that an earlier estimate of 3.6 × 10¹² dyn/cm² for this rigidity may need to be reduced by 0.5 × 10¹² dyn/cm². The theoretical travel-times of the phase PKJKP would then need to be increased by amounts ranging from zero to 40 seconds. It is shown that the use of Gutenberg's seismic data in place of that of Jeffreys would reduce the estimated rigidity of the inner core by a further 1.6 × 10¹² dyn/cm², approximately. It is suggested that Gutenberg's data lead to the lowest likely value for the rigidity of the inner core, namely 1.5 × 10¹² dyn/cm², so that, on all present evidence, it is improbable that the inner core is less than about twice as rigid as steel is at zero pressure.

Keith Edward Bullen

2010-01-01

369

Earth. Fourth edition  

Energy Technology Data Exchange (ETDEWEB)

This edition preserves the classical elements of geology while incorporating current findings and topics such as satellite data, climate change, the eruption of El Chichon, and acid rain. It incorporates the elementary ideas of structural geology and discussions of rock structures. The flow of geological materials between the interior and the surface is developed, and the modern approach of the interactions of the earth and its environmental envelope is discussed.

Press, F.; Siever, R.

1986-01-01

370

Google Earth Weather Bundle  

Science.gov (United States)

The Google Earth Weather Bundle, from the Department of Atmospheric Sciences at the University of Illinois, gives the user a suite of automatically updating weather products that can be overlaid in any fashion he or she desires. It can be downloaded from the department's web site at the University of Illinois, and is meant for worldwide use by a wide range of audiences, from the general public to meteorologists.

371

The Home Earth  

Science.gov (United States)

In the early 1990s, Sara Tweedie designed a very popular poster based on this visualization by Dave Pape. The poster depicted a very large version of this image with the word Earth above the image and the phrase Theres no place like home below it. There was a rumor that the posters were offered for sale by the Tennessee Valley Authority at one point.

Pape, Dave; Strong, Jim

1994-01-01

372

The exploited earth  

International Nuclear Information System (INIS)

This volume highlights the topic of the 'Geotechnica-93' conference: 'Conserving the earth - a challenge to science and technology'. 53 authors from the international scientific community, consulting, and industry deal in five sections with the following relevant subject areas: 1. Non environmentally harmful exploitation of resources, 2. Data acquisition, 3. Waste disposal and land reclamation, 4. Precautionary and conservation measures, and 5. Environmental policy and its acceptance. (orig./UA).

1994-01-01

373

Superhydrophobic diatomaceous earth  

Energy Technology Data Exchange (ETDEWEB)

A superhydrophobic powder is prepared by coating diatomaceous earth (DE) with a hydrophobic coating on the particle surface such that the coating conforms to the topography of the DE particles. The hydrophobic coating can be a self assembly monolayer of a perfluorinated silane coupling agent. The DE is preferably natural-grade DE where organic impurities have been removed. The superhydrophobic powder can be applied as a suspension in a binder solution to a substrate to produce a superhydrophobic surface on the substrate.

Simpson, John T. (Clinton, TN); D& #x27; Urso, Brian R. (Clinton, TN)

2012-07-10

374

Earth space plasma physics  

Energy Technology Data Exchange (ETDEWEB)

The paper reviews some of the major areas in which earth and solar plasma physics research will interact. This stems from the 1985 European Space Agency workshop, where physicists from these two disciplines made a commitment to cooperate closely in the next major European solar-terrestrial space missions (CLUSTER and SOHO). The research work concerns:- magnetic reconnection, filamentary structures of the magnetised plasmas of the solar system, astrophysics shock waves, and hydromagnetic waves of the solar system magnetised plasmas.

Saunders, M.

1988-02-01

375

Density of Earth's Layers  

Science.gov (United States)

In this activity, students measure the densities of samples of granite, basalt, peridotite/dunite, and an iron meteorite, which are used as representatives of the various layers of the Earth (crust, mantle, core). The samples are weighed to determine their mass, and the Archimedes Principle is used to determine volume. From these two properties, they calculate density, compare it to accepted values presented in the discussion, and answer questions about their observations.

Klosko, Eryn

376

Small transportable earth station  

Science.gov (United States)

This paper describes design and performance of C band (6/4 GHz) and K band (30/20 GHz) small transportable earth station for domestic satellite communication. These stations consist of three units, an antenna and two containers. Transmitter and receiver equipments are mounted in one container. Terminal equipment and power generator are mounted in the other container, thus enabling transportation by truck or helicopter. System performances are confirmed by experiments using Japanese Medium Capacity Communication Satellite for Experimental Purposes.

Egami, S.; Nara, T.; Kaitsuka, T.; Okamoto, T.

1980-08-01

377

Electromagnetic compatibility and earths  

International Nuclear Information System (INIS)

It is such the increment of applications of electric and electronic equipment in the modern companies that the lack of control of the electromagnetic perturbations, brings, get big losses and difficulties in the normal operations. The paper contribute to ago with base in the challenges that day-by-day are confronting, where the settings to earth, to be the foundation of the electric building, are fundamental for a good coexistence among the different equipment s.

2001-01-01

378

The Earth and planetary sciences.  

UK PubMed Central (United Kingdom)

During the last two decades the earth sciences community has become persuaded that the earth is a dynamic body; an engine driven by its internal heat. The major surface manifestation of this dynamism has been fragmentation of the earth's outer shell and subsequent relative horizontal movement of the pieces on a large scale. The driving force is convection within the earth, but much remains to be learned about the nature of the convection and the composition of the earth's interior. The other terrestrial planets show evidence of once having been hot, but their surfaces suggest long-term stability and lack evidence of continuing convection.

Wetherill GW; Drake CL

1980-07-01

379

Solar activity and the earth  

Energy Technology Data Exchange (ETDEWEB)

Attention is given to the influence of the sun on physicochemical processes in near-earth space, in the earth's atmosphere, and on the surface of the earth. Current theories on various aspects of solar activity, on the properties of the interplanetary medium, and on the interaction of this medium with the earth's magnetosphere are surveyed. Also treated are theories concerning the ways that solar disturbances affect the upper part (ionosphere) of the earth's atmosphere and the lower part (troposphere), where meteorological phenomena occur. The biological effects of the sun are assessed.

Miroshnichenko, L.I.

1981-01-01

380

EARTH ROADS ARE EASY  

Directory of Open Access Journals (Sweden)

Full Text Available The earliest European immigrants in America traveled on waterways and on pathways worn into the earth by animals and Native Americans. Once their communities began to thrive, settlers widened paths and cleared new roads and streets then began experimenting with inexpensive surfacing to reduce dust in dry weather and mud in wet. “Earth Roads Are Easy” investigates materials and techniques used to maintain primitive thoroughfares with a minimum of effort and expense. The options range from the mundane—clay, sand, gravel, calcium chloride, oil, and tar—to the extraordinary—water glass, adobe clay, beet juice, and carpeting.There is no more dfficult problem confronting highway engineers than that of properly constructing and maintaining an earth road. The work may be less spectacular than the construction and maintenance of hard-surfaced roads, but there is greater latitude in location, methods of construction and choice of materials, consequently there is more scope for the exercise of sound judgment on the part of the engineer.1

David O. Whitten

2000-01-01

 
 
 
 
381

Simulating the interplay between plasma transport, electric field, and magnetic field in the near-earth nightside magnetosphere  

Science.gov (United States)

The convection electric field resulting from the coupling of the Earth's magnetosphere with the solar wind and interplanetary magnetic field (IMF) drives plasma in the tail plasma sheet earthward. This transport and the resulting energy storage in the near Earth plasma sheet are important for setting up the conditions that lead to major space weather disturbances, such as storms and substorms. Penetration of plasma sheet particles into the near-Earth magnetosphere in response to enhanced convection is crucial to the development of the Region 2 field-aligned current system and large-scale magnetosphere-ionosphere (M-I) coupling, which results in the shielding of the convection electric field. In addition to the electric field, plasma transport is also strongly affected by the magnetic field, which is distinctly different from dipole field in the inner plasma sheet and changes with plasma pressure in maintaining force balance. The goal of this dissertation is to investigate how the plasma transport into the inner magnetosphere is affected by the interplay between plasma, electric field and magnetic field. For this purpose, we conduct simulations using the Rice Convection Model (RCM), which self-consistently calculates the electric field resulting from M-I coupling. In order to quantitatively evaluate the interplay, we improved the RCM simulations by establishing realistic plasma sheet particle sources, by incorporating it with a modified Dungey force balance magnetic field solver (RCM-Dungey runs), and by adopting more realistic electron loss rates. We found that plasma sheet particle sources strongly affect the shielding of the convection electric field, with a hotter and more tenuous plasma sheet resulting in less shielding than a colder and denser one and thus in more earthward penetration of the plasma sheet. The Harang reversal, which is closely associated with the shielding of the convection electric field and the earthward penetration of low-energy protons, is found to be located at lower latitudes and extend more dawnward for a hotter and more tenuous plasma sheet. In comparison with simulation runs under an empirical but not force balance magnetic field from the Tsyganenko 96 model, the simulation results show that transport under force-balanced magnetic field results in weaker pressure gradients and thus weaker R2 FAC in the near-earth region, weaker shielding of the penetration electric field and, as a result, more earthward penetration of plasma sheet protons and electrons with their inner edges being closer together and more azimuthally symmetric. To evaluate the effect of electron loss rate on ionospheric conductivity, a major contributing factor to M-I coupling, we run RCM-Dungey with a more realistic, MLT dependent electron loss rate established from observed wave activity. Comparing our results with those using a strong diffusion everywhere rate, we found that under the MLT dependent loss rate, the dawn-dusk asymmetry in the precipitating electron energy fluxes agrees better with statistical DMSP observations. The more realistic loss rate is much weaker than the strong diffusion limit in the inner magnetosphere. This allows high-energy electrons in the inner magnetosphere to remain much longer and produce substantial conductivity at lower latitudes. The higher conductivity at lower latitudes under the MLT dependent loss rate results in less efficient shielding in response to an enhanced convection electric field, and thus to deeper penetration of the ion plasma sheet into the inner magnetosphere than under the strong diffusion everywhere rate.

Gkioulidou, Malamati

382

Space Weather – Sun Earth Relations  

Directory of Open Access Journals (Sweden)

Full Text Available Sun, a star of spectral type G2 is the main source of energy to the Earth. Being close to the Earth, Sun pro-duces a resolvable disk of great detail, which is not possible for other stars. Solar flares and coronal mass ejections are the enigmatic phenomena that occur in the solar atmosphere and regularly bombard the Earth’s environment in addition to the solar wind. Thus it becomes important for us not only to understand these physical processes of the Sun, but in addition how these activities affect the Earth and it’s surrounding. Thus a branch of study called ‘Space Weather’ had emerged in the recent past, which connects the Sun Earth rela-tions. This paper details about the solar activity and associated energetic phenomena that occur in the atmosphere of the Sun and their influence on the Earth.

K. Sundara Raman

2011-01-01

383

Static Balance Norms in Children.  

Science.gov (United States)

OBJECTIVES: The ability to sustain single leg stance and tandem stance is often used to determine the balance abilities of children, particularly after ankle or foot injury. The aim of this study was to assess performance norms on timed static balance tests in children aged 4 to 15?years. DESIGN: Cross-sectional study METHODS: Children from schools across the Republic of Ireland (n?=?534) were tested on six balance tests as well as a standing broad jump. RESULTS: Interquartile ranges for the tests are presented for each age group (4-5, 6-7, 8-9, 10-11 and 12+?years). The results confirm the improvement in balance performance as children age especially after the 7 to 8th year. Girls tend to outperform boys across all balance tests. There is a ceiling effect for some single leg stance and tandem stance tests after the age of 7?years. CONCLUSIONS: Results can be used for comparative purposes against age appropriate normative balance test scores. This removes the estimation from balance testing and the risk of applying an insufficient cut-off time. Copyright © 2013 John Wiley & Sons, Ltd. PMID:23703740

Condon, Cillin; Cremin, Katie

2013-05-23

384

Static Balance Norms in Children.  

UK PubMed Central (United Kingdom)

OBJECTIVES: The ability to sustain single leg stance and tandem stance is often used to determine the balance abilities of children, particularly after ankle or foot injury. The aim of this study was to assess performance norms on timed static balance tests in children aged 4 to 15?years. DESIGN: Cross-sectional study METHODS: Children from schools across the Republic of Ireland (n?=?534) were tested on six balance tests as well as a standing broad jump. RESULTS: Interquartile ranges for the tests are presented for each age group (4-5, 6-7, 8-9, 10-11 and 12+?years). The results confirm the improvement in balance performance as children age especially after the 7 to 8th year. Girls tend to outperform boys across all balance tests. There is a ceiling effect for some single leg stance and tandem stance tests after the age of 7?years. CONCLUSIONS: Results can be used for comparative purposes against age appropriate normative balance test scores. This removes the estimation from balance testing and the risk of applying an insufficient cut-off time. Copyright © 2013 John Wiley & Sons, Ltd.

Condon C; Cremin K

2013-05-01

385

Phase balancing using simulated annealing  

Energy Technology Data Exchange (ETDEWEB)

Deregulation eliminates the boundary of the territory of the monopoly power industry. Competition forces utilities to improve power quality as well as to reduce investment and operation costs. Feeder imbalance describes a situation in which the voltages of a three-phase voltage source are not identical in magnitude, or the phase differences between them are not 120 electrical degrees, or both. It affects motors and other devices that depend upon a well-balanced three-phase voltage source. Phase balancing is to make the voltages balanced at each load point of the feeder. Phase swapping is a direct approach for phase balancing with the minimum cost. Phase balancing can enhance utilities' competitive capability by improving reliability, quality, and reducing costs. Therefore, phase balancing optimization is nowadays receiving more attention in the power industry, especially in today's deregulating environments. The non-linear effects, such as, voltage drops and energy losses, make the problem difficult to solve. This paper introduces Simulated Annealing as an effective method to solve a power distribution phase balancing problem with its non-linear effects.

Zhu, J.; Bilbro, G.; Chow, M.Y.

1999-11-01

386

Gender differences in balance performance at the time of retirement.  

UK PubMed Central (United Kingdom)

BACKGROUND: Impairments in balance performance are a commonly accepted risk factor for falling in older people. Since there is a higher reported incidence of falling in women, it is of interest to test whether this correlates with poorer balance performance in women than men at the time of retirement in order to plan health promotional strategies. The purpose of this study was to investigate whether any gender differences exist in balance performance in people approaching retirement age. METHODS: Ninety-seven healthy volunteers (44 males, 53 females) planning to retire shortly were enrolled in the study (age range 50-67 years). Balance assessments during quiet standing were performed under various conditions; feet together eyes open, feet together eyes closed and single limb stance eyes open. The range of centre of pressure displacement in both the anterior-posterior and medial-lateral planes was collected for each task using a force platform. FINDINGS: For several of the balance tasks the men exhibited a statistically significant larger range of centre of pressure displacement than the women (P<0.01). However, after normalising the data for height, no gender differences were seen. Over half of the group failed to complete all three single limb stance trials on both limbs. INTERPRETATION: When the data was normalised for height, no differences were found in static balance performance between men and women of retirement age. A number of participants demonstrated balance impairments whilst performing the single limb stance likely to affect functional activities. Health promotional messages should be targeted equally at men and women.

Bryant EC; Trew ME; Bruce AM; Kuisma RM; Smith AW

2005-03-01

387

Underground radon gas concentrations related to earth tides  

Energy Technology Data Exchange (ETDEWEB)

The paper presents the preliminary radon concentrations recorded in a former gypsum mine near Walferdange (Luxembourg), which hosts an underground laboratory for geo dynamics and seismology. First results show that besides outside temperature and atmospheric air pressure, radon concentrations seem to be influenced by earth tides.

Kies, A.; Majerus, J. [Centre Universitaire, Luxembourg (Luxembourg); D' Oreye De Lantremange, N. [European Centre for Geodynamics and Seismology, Walferdange (Luxembourg)

1999-08-01

388

Can the Earth's dynamo run on heat alone?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The power required to drive the geodynamo places significant constraints on the heat passing across the core–mantle boundary and the Earth's thermal history. Calculations to date have been limited by inaccuracies in the properties of liquid iron mixtures at core pressures and temperatures. Here we r...

Gubbins, D.; Alfè, D.; Masters, G.; Price, G.D.; Gillan, M.J.

389

Rare earth vapor laser studies  

International Nuclear Information System (INIS)

The fluorescence decay rates of vapor phase neodymium aluminum chloride complex (Nd-Al-Cl) and neodymium-thd-chelate have been measured as functions of temperature, partial pressure and optical excitation intensity. Fluorescence quenching due to both ground and excited state collisions was observed in Nd-Al-Cl vapor. In constrast, quenching in the Nd-thd vapor was found to be dominated by multiquantum excitation of molecular vibrations. The fluorescence kinetics of Tb-Al-Cl vapor have also been examined under conditions of intense excitation of terbium 5d levels by a KrF laser source. Both prompt and delayed fluorescence of the 4f8(5D4) metastable level were observed together with evidence of excited-state collisional quenching. In laser amplifier experiments, a transient (greater than or equal to 10 ?sec) population inversion was produced in Nd-Al-Cl vapor with a small signal gain coefficient greater than or equal to 0.25%/cm and a stored energy density approximately equal to 35 J/liter. Available data for the rare earth vapors are related to scaling requirements of large amplifiers for laser fusion application

1977-10-20

390

A bilateral ankle manipulator to investigate human balance control.  

Science.gov (United States)

The ankles play an important role in human balance. In most studies investigating balance control the contribution of the left and right leg is not separated. However, in certain pathologies such as stroke and Parkinson's disease, balance control can be asymmetric. Here, a bilateral ankle perturbator (BAP) is presented, which applies support surface rotations to both ankles independently. The device consists of two small foot-size support surfaces, which are independently actuated. The BAP device can operate in either angle or torque control mode. The device is able to apply support surface rotations up to 8.6° with a bandwidth of 42 Hz. Additionally the platforms can be replaced by 6-DoF force plates to measure the center of pressure underneath each foot. With the optional force plates the bandwidth decreases to 16 Hz as a result of the additional weight. Two possible applications of the device to investigate human balance control are demonstrated: ankle stiffness by applying minimum jerk profiles and sensory reweighting of the proprioceptive information. In conclusion, we developed a bilateral ankle perturbator which is able to apply support surface rotations to both ankles independently. The major application of the device will be to investigate the contribution of both ankles to human balance control, and the interactions in balance control between both legs. PMID:21859606

Schouten, Alfred C; Boonstra, Tjitske A; Nieuwenhuis, Frank; Campfens, S Floor; van der Kooij, Herman

2011-08-22

391

Letters in the earth sciences: written in the past useful in the future  

Directory of Open Access Journals (Sweden)

Full Text Available This contribution presents a balance of the research performed in some national and international projects concerning the history of seismology with a view to the scientific and historical use of scientific correspondence between earth science scholars. We also present some of the contents of the scientific correspondence studied in the course of those projects. As many scholars and observatories, above all in the 19th century, operated in different sectors of the earth sciences at the same time, we highlight the importance of a coordinated collaboration between scholars and relevant institutions and in valorising the epistolary assets produced by the earth sciences observation networks.

Graziano Ferrari

2009-01-01

392

Inference on the Nature and the Mass of Earth's Late Veneer from Noble Metals and Gases  

CERN Multimedia

Noble metals and gases are very sensitive to the late accretion to the Earth of asteroids and comets. We present mass balance arguments based on these elements that indicate that 0.7E22-2.7E22 kg of extraterrestrial bodies struck the Earth after core formation and that comets comprised less than 1E-5 by mass of the impacting population. These results imply that the dynamics of asteroids and comets changed drastically with time and that biogenic elements and prebiotic molecules were not delivered to the Earth by comets but rather by carbonaceous asteroids.

Dauphas, N

2001-01-01

393

A reconciled estimate of ice-sheet mass balance.  

DEFF Research Database (Denmark)

We combined an ensemble of satellite altimetry, interferometry, and gravimetry data sets using common geographical regions, time intervals, and models of surface mass balance and glacial isostatic adjustment to estimate the mass balance of Earth's polar ice sheets. We find that there is good agreement between different satellite methods--especially in Greenland and West Antarctica--and that combining satellite data sets leads to greater certainty. Between 1992 and 2011, the ice sheets of Greenland, East Antarctica, West Antarctica, and the Antarctic Peninsula changed in mass by -142 ± 49, +14 ± 43, -65 ± 26, and -20 ± 14 gigatonnes year(-1), respectively. Since 1992, the polar ice sheets have contributed, on average, 0.59 ± 0.20 millimeter year(-1) to the rate of global sea-level rise.

Shepherd, Andrew; Ivins, Erik R

2012-01-01

394

A reconciled estimate of ice-sheet mass balance.  

UK PubMed Central (United Kingdom)

We combined an ensemble of satellite altimetry, interferometry, and gravimetry data sets using common geographical regions, time intervals, and models of surface mass balance and glacial isostatic adjustment to estimate the mass balance of Earth's polar ice sheets. We find that there is good agreement between different satellite methods--especially in Greenland and West Antarctica--and that combining satellite data sets leads to greater certainty. Between 1992 and 2011, the ice sheets of Greenland, East Antarctica, West Antarctica, and the Antarctic Peninsula changed in mass by -142 ± 49, +14 ± 43, -65 ± 26, and -20 ± 14 gigatonnes year(-1), respectively. Since 1992, the polar ice sheets have contributed, on average, 0.59 ± 0.20 millimeter year(-1) to the rate of global sea-level rise.

Shepherd A; Ivins ER; A G; Barletta VR; Bentley MJ; Bettadpur S; Briggs KH; Bromwich DH; Forsberg R; Galin N; Horwath M; Jacobs S; Joughin I; King MA; Lenaerts JT; Li J; Ligtenberg SR; Luckman A; Luthcke SB; McMillan M; Meister R; Milne G; Mouginot J; Muir A; Nicolas JP; Paden J; Payne AJ; Pritchard H; Rignot E; Rott H; Sørensen LS; Scambos TA; Scheuchl B; Schrama EJ; Smith B; Sundal AV; van Angelen JH; van de Berg WJ; van den Broeke MR; Vaughan DG; Velicogna I; Wahr J; Whitehouse PL; Wingham DJ; Yi D; Young D; Zwally HJ

2012-11-01

395

A reconciled estimate of ice-sheet mass balance.  

Science.gov (United States)

We combined an ensemble of satellite altimetry, interferometry, and gravimetry data sets using common geographical regions, time intervals, and models of surface mass balance and glacial isostatic adjustment to estimate the mass balance of Earth's polar ice sheets. We find that there is good agreement between different satellite methods--especially in Greenland and West Antarctica--and that combining satellite data sets leads to greater certainty. Between 1992 and 2011, the ice sheets of Greenland, East Antarctica, West Antarctica, and the Antarctic Peninsula changed in mass by -142 ± 49, +14 ± 43, -65 ± 26, and -20 ± 14 gigatonnes year(-1), respectively. Since 1992, the polar ice sheets have contributed, on average, 0.59 ± 0.20 millimeter year(-1) to the rate of global sea-level rise. PMID:23197528

Shepherd, Andrew; Ivins, Erik R; A, Geruo; Barletta, Valentina R; Bentley, Mike J; Bettadpur, Srinivas; Briggs, Kate H; Bromwich, David H; Forsberg, René; Galin, Natalia; Horwath, Martin; Jacobs, Stan; Joughin, Ian; King, Matt A; Lenaerts, Jan T M; Li, Jilu; Ligtenberg, Stefan R M; Luckman, Adrian; Luthcke, Scott B; McMillan, Malcolm; Meister, Rakia; Milne, Glenn; Mouginot, Jeremie; Muir, Alan; Nicolas, Julien P; Paden, John; Payne, Antony J; Pritchard, Hamish; Rignot, Eric; Rott, Helmut; Sørensen, Louise Sandberg; Scambos, Ted A; Scheuchl, Bernd; Schrama, Ernst J O; Smith, Ben; Sundal, Aud V; van Angelen, Jan H; van de Berg, Willem J; van den Broeke, Michiel R; Vaughan, David G; Velicogna, Isabella; Wahr, John; Whitehouse, Pippa L; Wingham, Duncan J; Yi, Donghui; Young, Duncan; Zwally, H Jay

2012-11-30

396

Solar energy resources not accounted in Brazilian National Energy Balance  

Energy Technology Data Exchange (ETDEWEB)

The main development vector of a society is the energy. The solar energy is the main energy source on the planet earth. Brazil is a tropical country, and the incident solar energy on its soil (15 trillion MWh/year) is 20,000 times its annual oil production. Several uses of solar energy are part of our lives in a so natural way that it despised in the consumption and use energy balance. In Brazil, solar energy is used directly in many activities and not accounted for in Energy Balance (BEN 2007), consisting of a virtual power generation. This work aims to make a preliminary assessment of solar energy used in different segments of the Brazilian economy. (author)

Pinheiro, Paulo Cesar da Costa [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Mecanica], Emails: pinheiro@netuno.Lcc.ufmg.br, pinheiro@demec.ufmg.br

2009-07-01

397

Walking (Gait), Balance, and Coordination Problems  

Science.gov (United States)

... MS Pediatric MS Related Conditions Walking (Gait), Balance, & Coordination Problems The following combo-box uses JavaScript to ... Reader . Related Pages Dizziness & Vertigo Walking (Gait), Balance, & Coordination Problems You Can...Improve Your Balance You Can... ...

398

The earth dynamic system: the earth rotation vs mantle convection  

Directory of Open Access Journals (Sweden)

Full Text Available The earth dynamic system is one of the key scientific questions on the earth science. The thermodynamic behavior and gravity force of the earth and the rheology nature of the mantle prove that mantle convection is the main power source leading the lithosphere to break and move. Yet the directivity of both the structures in the crust and plate movement reminds of the earth rotation. Here we demonstrate that the mantle convection and inertia force of the earth rotation affect each other, the former being the power source of lithosphere plate break and motion, and the latter determining the direction of the mantle convection and plate motion. The sense of plate motion depends on the mantle upwells, whose trends are controlled by the earth rotation. The geometric shapes of the plate boundaries can adjust the direction of plate movement.

Shuping Chen

2010-01-01

399

Solar energy and its interaction with Earth`s atmosphere  

Energy Technology Data Exchange (ETDEWEB)

The Sun is responsible for many of the phenomena on Earth, including the maintenance of life. In addition, magnetic storms, capable of disrupting radio communication, and auroral displays are associated with solar events. Man-made electrical, satellite, and communication systems are affected strongly by the near-Earth space environments. The purpose of this paper is to review briefly the interaction of solar activity with the near-Earth environment. These processes can be studied by examing two sets of interactions. That is, the interaction of the solar electromagnetic output with the Earth`s neutral atmosphere, and the solar corpuscular output with the geomagnetic field. In order to understand the types of interactions one needs to know more details of the interacting components. Therefore, the near-Earth environments which comprise neutral atmospheric, ionospheric and magnetospheric regions will be discussed in relation to the direct and indirect influences of solar activity.

Tulunay, Y. [Armed Forces Radiobiology Research Inst., Bethesda, MD (United States)]|[DLR Inst. of Aerospace Medicine, Cologne (Germany)]|[NASA, Goddard Space Flight Center, Greenbelt, MD (United States)

1993-12-31

400

High-pressure optical studies  

International Nuclear Information System (INIS)

High pressure experimentation may concern intrinsically high pressure phenomena, or it may be used to gain a better understanding of states or processes at one atmosphere. The latter application is probably more prevelant in condensed matter physics. Under this second rubric one may either use high pressure to perturb various electronic energy levels and from this pressure tuning characterize states or processes, or one can use pressure to change a macroscopic parameter in a controlled way, then measure the effect on some molecular property. In this paper, the pressure tuning aspect is emphasized, with a lesser discussion of macroscopic - molecular relationships. In rare earth chelates the efficiency of 4f-4f emission of the rare earth is controlled by the feeding from the singlet and triplet levels of the organic ligand. These ligand levels can be strongly shifted by pressure. A study of the effect of pressure on the emission efficiency permits one to understand the effect of ligand modification at one atmosphere. Photochromic crystals change color upon irradiation due to occupation of a metastable ground state. In thermochromic crystals, raising the temperature accomplishes the same results. For a group of molecular crystals (anils) at high pressure, the metastable state can be occupied at room temperature. The relative displacement of the energy levels at high pressure also inhibits the optical process. Effects on luminescence intensity are shown to be consistent. In the area of microscopic - molecular relationships, the effect of viscosity and dielectric properties on rates of non-radiative (thermal) and radiative emission, and on peak energy for luminescence is demonstrated. For systems which can emit from either of two excited states depending on the interaction with the environment, the effect of rigidity of the medium on the rate of rearrangement of the excited state is shown

1981-01-01