WorldWideScience
 
 
1

Dual shell pressure balanced vessel  

Science.gov (United States)

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

Pressure balance under hydrothermal conditions  

Science.gov (United States)

Low pressure, low temperature growth of potassium titanyl phosphate (KTP) crystals, the material of choice for certain kinds of laser eye surgery apparatus and other applications, requires hydrothermal growth in pressure balance noble metal cans. This paper discusses the problem of pressure balancing the Au cans used for hydrothermal KTP growth. The P-V-T behavior of the pressure balance medium (H2O) and the growth medium (KTP saturated K2HPO4) are described and the source of the 'dimples' in growth cans is explained and remediation strategies are suggested.

Laudise, R. A.; Bridenbaugh, P. M.; Iradi, T.

1994-06-01

3

Pressure balance at the magnetopause: Experimental studies  

CERN Document Server

The pressure balance at the magnetopause is formed by magnetic field and plasma in the magnetosheath, on one side, and inside the magnetosphere, on the other side. In the approach of dipole earth's magnetic field configuration and gas-dynamics solar wind flowing around the magnetosphere, the pressure balance predicts that the magnetopause distance R depends on solar wind dynamic pressure Pd as a power low R ~ Pd^alpha, where the exponent alpha=-1/6. In the real magnetosphere the magnetic filed is contributed by additional sources: Chapman-Ferraro current system, field-aligned currents, tail current, and storm-time ring current. Net contribution of those sources depends on particular magnetospheric region and varies with solar wind conditions and geomagnetic activity. As a result, the parameters of pressure balance, including power index alpha, depend on both the local position at the magnetopause and geomagnetic activity. In addition, the pressure balance can be affected by a non-linear transfer of the solar ...

Suvorova, A V

2011-01-01

4

Rare earth luminescence under pressure  

International Nuclear Information System (INIS)

The luminescence properties of different rare earth ions (RE3+ : Sm3+, Tb3+ and Er3+) in lithium fluoroborate glasses and oxyfluoride nanocrystalline glass-ceramics have been analyzed as a function of the pressure. The roles of the pressure-induced energy transfer between optically active ions, their host local structures and the energy trap centers in the quenching of the rare earth luminescence are discussed

2011-09-25

5

Rare-Earth Economics: The Balance Problem  

Science.gov (United States)

TMS has forged cooperative agreements with several carefully selected organizations that actively work to benefit the materials science community. In this occasional series, JOM will provide an update on the activities of these organizations. This installment, by the Center for Resource Recovery & Recycling (CR3), focuses on the importance of recycling of rare earths to mitigate the so-called Balance Problem. The CR3 is a research center established by Worcester Polytechnic Institute, Colorado School of Mines, and KU Leuven. Twenty-eight corporations and national laboratories along with support from the U.S. National Science Foundation's Industry University Cooperative Research Center (I/UCRC) program are sponsors of the center.

Binnemans, K.; Jones, P. T.; Van Acker, K.; Blanpain, B.; Mishra, B.; Apelian, D.

2013-07-01

6

Pressure-balanced stab connection  

Energy Technology Data Exchange (ETDEWEB)

This patent describes an apparatus for sealingly connecting a flow bore of a wellhead to a flowline. It consists of: a stab member including a stab body. The stab body has a stab body bore. One end of the stab body bore exiting from the stab body and being in fluid communication with the flow bore and the other end of the stab body bore exiting from a side of the stab body through a stab body side port; a stab receptacle mounted on the wellhead and having a stab receiving bore for receiving the stab body; the stab receptacle having a receptacle flow bore. One end of the receptacle flow bore being in fluid communication with the stab receiving bore and the other end of the receptacle flow bore exiting the stab receptacle and being in fluid communication with the flowline; means for establishing fluid communication between the stab body side port and the one end of the receptacle flow bore when the stab body is received within the stab receiving bore. It includes means disposed on the stab member for orienting the stab member with respect to the Christmas tree for ensuring the alignment of the stab body side port with the one end of the receptable flow bore when the stab body is received within the stab receiving bore; and first and second sealing means disposed on the stab body above and below the stab body side port, respectively, for sealing engagement with the walls of the stab receiving bore above and below the one end of the receptable flow bore for establishing a non-blow-apart, fluid pressure sealed flow passage between the stab body bore of the stab member and the receptacle flow bore of the stab receptacle when the stab body is landed within the stab receiving bore.

Best, M.J.A.; Jones, R.H.; Hynes, J.H.; Pond, R.J.; Gordon, C.R.

1987-09-22

7

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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.

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

2010-01-01

8

The energy balance of the earth' surface : a practical approach  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study is devoted to the energy balance of the earth's surface with a special emphasis on practical applications. A simple picture of the energy exchange processes that take place at the ground is the following. Per unit time and area an amount of radiant energy is supplied to the surface. This radiation originates partly from the sun, but an~ other fraction is coming from the atmosphere (= infra-red radiation emitted by clouds, water vapour and CO 2

1982-01-01

9

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.

Yevgeniy V. Lapovok

2010-04-01

10

Why is the earth not burning ? The earth radiative energy balance  

CERN Document Server

The concept of energy balance is a key one in climate science. Yet, students may find it counterintuitive: while it is obvious that some energy comes in from the sun, the part coming out is more elusive. Asking them why the earth is not burning after billions of years of exposure to the sun, takes them to the question "where does the energy goes?" A series of Fermi like calculations then convinces them that storage capabilities are negligible compared to the amount of energy coming in: the earth necessarily re-emits what it receives.

Bret, A

2011-01-01

11

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

12

Why is the earth not burning ? The earth radiative energy balance  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The concept of energy balance is a key one in climate science. Yet, students may find it counterintuitive: while it is obvious that some energy comes in from the sun, the part coming out is more elusive. Asking them why the earth is not burning after billions of years of exposure to the sun, takes them to the question "where does the energy goes?" A series of Fermi like calculations then convinces them that storage capabilities are negligible compared to the amount of energy...

Bret, A.

2011-01-01

13

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 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 t...

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

2007-01-01

14

Statistical Behavior of Quasi-Steady Balanced Reconnection in Earth's Magnetosphere  

Science.gov (United States)

Magnetic reconnection between Earth's magnetosphere and the solar wind results in several modes of response, including the impulsive substorm and the quasi-steady mode known as steady magnetospheric convection (SMC). SMC events are theorized to result from balancing the dayside and nightside reconnection rates. The reasons the magnetosphere responds with different modes are not fully known. This dissertation comprises statistical data analysis of the SMC mode to investigate the solar wind conditions and magnetospheric properties during these events. A comprehensive list of SMC events is selected from 1997-2011. In the first of three studies, an association between SMCs and solar wind stream interfaces (SI) is identified in the declining phase of Solar Cycle 23. SMC occurrence peaks 12-24 hours after an SI if the solar wind is geoeffective. The subset of SI-associated SMCs occurs during fast solar wind velocity, in contrast to previous results, but the driving electric field imposed on the magnetosphere (Ey) is the same for SI-associated and unassociated SMC events. Therefore the magnitude and steadiness of E y is the most important solar wind parameter for an SMC to occur. The second study shows that magnetotail convection is significantly different for SMC events, compared to quiet intervals and isolated substorms. Fast flows transporting enhanced magnetic flux are deflected toward the dawn and dusk flanks during SMC. Flow diversion is due to a broad high pressure region in the inner magnetosphere. The interval preceding SMC events is found to set up the magnetotail conditions that assist balanced reconnection. In particular inner magnetosphere pressure before SMCs is enhanced from substorm levels but not as high as SMC levels. The final study shows that nearly all SMCs are preceded by a substorm expansion. In rare cases when an SMC occurs without a preceding substorm, we hypothesize that the distant x-line is able to balance a weak solar wind driver. These results help explain how quasi-steady magnetospheric convection occurs. A southward turning of the solar wind and positive Ey leads to dayside reconnection and a substorm onset occurs. Plasma injections from the near-Earth nightside x-line increase the pressure in the inner magnetosphere. If positive Ey continues to drive dayside reconnection, the nightside x-line will stabilize to match it. Tail flux is diverted towards the flanks by pressure gradients and returns to the dayside. This convection pattern keeps the magnetosphere in its balanced reconnection mode.

Kissinger, Jennifer Eileen

15

Pressure Balanced, Low Hysteresis Finger Seal Test Results  

Science.gov (United States)

The purpose of this presentation is to demonstrate: low cost photoetching fabrication technique; pressure balanced finger seal design; and finger seal operation. The tests and analyses includes: finger seal air leakage analysis; rotor-run out and endurance tests; and extensive analytical work and rig testing.

Arora, Gul K.; Proctor, Margaret; Steinetz, Bruce M.; Delgado, Irebert R.

2000-01-01

16

Rigidly framed earth retaining structures thermal soil structure interaction of buildings supporting unbalanced lateral earth pressures  

CERN Document Server

Structures placed on hillsides often present a number of challenges and a limited number of economical choices for site design. An option sometimes employed is to use the building frame as a retaining element, comprising a Rigidly Framed Earth Retaining Structure (RFERS). The relationship between temperature and earth pressure acting on RFERS, is explored in this monograph through a 4.5 year monitoring program of a heavily instrumented in service structure. The data indicated that the coefficient of earth pressure behind the monitored RFERS had a strong linear correlation with temperature. The study also revealed that thermal cycles, rather than lateral earth pressure, were the cause of failure in many structural elements. The book demonstrates that depending on the relative stiffness of the retained soil mass and that of the structural frame, the developed lateral earth pressure, during thermal expansion, can reach magnitudes several times larger than those determined using classical earth pressure theories....

Aboumoussa, Walid

2014-01-01

17

Pressure-temperature Phase Diagram of the Earth  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Based on a pressure-temperature (P-T) phase diagram model of the Earth, Jones & Lineweaver (2010) described uninhabited terrestrial liquid water. Our model represents the atmosphere, surface, oceans and interior of the Earth - allowing the range of P-T conditions in terrestrial environments to be compared to the phase regime of liquid water. Here we present an overview and additional results from the Earth model on the location of the deepest liquid water on Earth and the ma...

Jones, Eriita; Lineweaver, Charles

2010-01-01

18

Molecular atmospheric transmittance function in the range of 2-400 ?m and Earth radiation balance.  

Science.gov (United States)

Mechanisms of the influence of the atmospheric transmission function, in the range 2-400 ?m and especially in the windows 8-13 and 3-4 ?m, on the thermal balance of the Earth's atmosphere are discussed. The negative and positive feedbacks between the absorption of the outgoing heat radiation in the atmosphere and the heating of the Earth's surface are considered. The database GEISA-92, which provides spectral line parameters of atmospheric constituents, has been used for simulations of infrared radiation transfer and the Earth's radiation balance. The temperature dependence of the molecular transmission function is calculated, and three steady states for Earth radiation balance are obtained. A type of the radiation balance, leading to "closing" of the atmospheric transmittance window 8-13 ?m and development of the explosive greenhouse effect, is discussed.

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

1997-01-01

19

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

20

Rare earth metals under high pressure  

International Nuclear Information System (INIS)

Strong systematics in the phase diagrams of the rare earth metals have been revealed recently. These systematics in many properties of the rare earth metals are closely related to the electronic structure of the individual free atoms. This relation as well as the special 'intermediate valence state' of the elements Cerium, Europium and Ytterbium are explained on typical examples. (orig.) 891 IHOE/orig. 892 MKO

1980-01-01

 
 
 
 
21

Earth pressures against- and stability of retaining structures  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The objective of the presented research is to investigate methods used to calculate earth pressures against- and the stability of retaining structures. The classical methods of calculating earth pressures are covered in detail. They are named after their creators Charles-Augustin de Coulomb and William John Macquorn Rankine. A special interest is taken in a variant of Rankine?s theory developed at Norges teknisk- naturvitenskapelige universitet (NTNU) that incorporates cohesive propertie...

Sigurður Már Valsson 1982

2011-01-01

22

Economics as if the earth really mattered. Putting balance back on the balance sheet.  

Science.gov (United States)

Some of the thinking in the economic realm which affects the relationship between the economy and the environment is discussed. The standard economic model inherently conflicts with the environment. Humans as consumers have their needs met by maximizing production and efficiency in a free market economy, where an invisible hand guides to profit. The question is raised as to what the environmental impact is for economic growth. The need for clean air, water, and preservation of other living things is not met. It is argued that pollution is a necessary byproduct of production. Economic progress as measured by gross national product (GNP) cannot account for the degradation of nature, e.g., the Alaskan oil spill actually increased GNP. Traditional economics also tell little about the maldistribution of wealth. It is pointed out that Americans spend $5 billion a year on special diets while 400 million around the world are undernourished. Limits to natural resources are also not accounted for by economic theorists, or the value of the seemingly free life-sustaining services performed by a forest in purifying air, preventing erosion and flooding, regulating climate, and supporting biological diversity. It is pointed out that restructuring must occur if the capacity of the Earth to support life is classed in economic terms as an externality. Steady state economic models consider the cycles of production and consumption in the context of the surrounding ecosystem of waste and raw materials and try to achieve a state of equilibrium. Despite the 1972 President's Commission on Population Growth and the American Future's statement that population growth is not necessary for a vital economy, the mythology exists that the economy will collapse, personal income will drop, and business will decline without an ever-growing population. A summary on positive outcomes of zero population growth is given. The economist Julian Simon promotes the view that there is no environmental degradation and technological fixes and human ingenuity will keep prosperity growing. Economic growth is seen as the cure for poverty, unemployment, and other ills. Technology has its shortcomings as pesticides and soil depletion have shown. Food supplies have dropped. Sustainability with all its lack of specificity has come to mean more rapid economic growth in both developed and developing countries, with assumptions of an infinite universe and economic expansion. A steady state economy aims to reduce overconsumption and stop population growth in order to balance the economic system in the ecosystem. PMID:12284468

Sherman, D

1991-09-01

23

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

International Nuclear Information System (INIS)

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

24

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

25

Magnetic measurement of rare earth ferromagnet gadolinium under high pressure  

Energy Technology Data Exchange (ETDEWEB)

Magnetic property of rare earth ferromagnet gadolinium(Gd: T{sub c}=293 K) has been observed under pressures up to 15 GPa, using a miniature diamond anvil cell (DAC) installed in a SQUID system. Pressurization suppresses both the ferromagnetic moment and the transition temperature with increasing pressure. In the pressure region above 6 GPa, the ferromagnetic signal has disappeared. The structural analysis, however, suggests that the crystal symmetry does not change in the pressure region up to 9 GPa. The results will be discussed on the exchange interaction among the isotropic 4f-metallic system.

Iwamoto, Tomoharu; Mito, Masaki; Hidaka, Masako; Kawae, Tatsuya; Takeda, Kazuyoshi

2003-05-01

26

High Pressure, Earth-Storable Rocket Technology.  

Science.gov (United States)

The effect of elevated chamber pressure on combustion efficiency and heat transfer has been determined at the 100 lbf (445 N) thrust level for nitrogen tetroxide propellants. Measurements were made up to 500 psia (3.45Mpa) with testbed hardware; tests at ...

D. M. Jassowski

1997-01-01

27

Stability of hydrocarbons at deep Earth pressures and temperatures  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Determining the thermochemical properties of hydrocarbons (HCs) at high pressure and temperature is a key step toward understanding carbon reservoirs and fluxes in the deep Earth. The stability of carbon-hydrogen systems at depths greater than a few thousand meters is poorly understood and the extent of abiogenic HCs in the Earth mantle remains controversial. We report ab initio molecular dynamics simulations and free energy calculations aimed at investigating the formation of higher HCs from...

Spanu, Leonardo; Donadio, Davide; Hohl, Detlef; Schwegler, Eric; Galli, Giulia

2011-01-01

28

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

29

EDITORIAL: The Earth radiation balance as driver of the global hydrological cycle  

Science.gov (United States)

Variations in the intensity of the global hydrological cycle can have far-reaching effects on living conditions on our planet. While climate change discussions often revolve around possible consequences of future temperature changes, the adaptation to changes in the hydrological cycle may pose a bigger challenge to societies and ecosystems. Floods and droughts are already today amongst the most damaging natural hazards, with floods being globally the most significant disaster type in terms of loss of human life (Jonkman 2005). From an economic perspective, changes in the hydrological cycle can impose great pressures and damages on a variety of industrial sectors, such as water management, urban planning, agricultural production and tourism. Despite their obvious environmental and societal importance, our understanding of the causes and magnitude of the variations of the hydrological cycle is still unsatisfactory (e.g., Ramanathan et al 2001, Ohmura and Wild 2002, Allen and Ingram 2002, Allan 2007, Wild et al 2008, Liepert and Previdi 2009). The link between radiation balance and hydrological cycle Globally, precipitation can be approximated by surface evaporation, since the variability of the atmospheric moisture storage is negligible. This is the case because the fluxes are an order of magnitude larger than the atmospheric storage (423 x 1012 m3 year-1 versus 13 x 1012 m3 according to Baumgartner and Reichel (1975)), the latter being determined by temperature (Clausius-Clapeyron). Hence the residence time of evaporated water in the atmosphere is not more than a few days, before it condenses and falls back to Earth in the form of precipitation. Any change in the globally averaged surface evaporation therefore implies an equivalent change in precipitation, and thus in the intensity of the global hydrological cycle. The process of evaporation requires energy, which it obtains from the surface radiation balance (also known as surface net radiation), composed of the absorbed solar and net thermal radiative exchanges at the Earth's surface. Globally averaged, this surface radiation balance is positive, since radiative absorption, scattering and emission in the climate system act to generate an energy surplus at the surface and an energy deficit in the atmosphere (Liepert 2010). Evaporation, or more precisely its energy equivalent, the latent heat flux, is the main process that compensates for this imbalance between surface and atmosphere, since the latent heat dominates the convective energy flux over sensible heating. The radiative energy surplus at the surface is thus mainly consumed by evaporation and moist convection and subsequently released in the atmosphere through condensation. This implies that any alterations in the available radiative energy will induce changes in the water fluxes. Our focus in this editorial is therefore on the surface radiation balance as the principal driver of the global hydrological cycle. Note that this energetic view is in agreement with that of Richter and Xie (2008) who argue that the spatial and temporal behaviour of the process of evaporation is controlled by surface and atmospheric properties such as atmospheric stability, wind speed, moisture deficit and moisture availability. From radiation theory it is expected that with increasing radiative absorption due to abundance of anthropogenic greenhouse gases in the atmosphere and consequent warming, the emission of thermal energy from the atmosphere towards the surface is increasing (known as downward thermal radiation). This enhances the radiative energy surplus at the surface, and, where surface water is not limited, fuels evaporation besides warming the Earth's surface. The enhanced greenhouse effect therefore tends to accelerate the hydrological cycle, as also shown in many climate model simulations with increasing levels of greenhouse gases (e.g., IPCC 2007, but also see Yang et al 2003, Andrews et al 2009). We can assume that the increase in greenhouse gases since preindustrial times had already led to a substantial increase of downw

Wild, Martin; Liepert, Beate

2010-06-01

30

Earth in the balance - ecology and the human spirit  

Energy Technology Data Exchange (ETDEWEB)

This book by Senator Albert Gore presents a global prospective on the environmental crisis facing the Earth. The chapters are framed in the twin ideas of the threat posed by human civilization to the global environment and the threat to human civilization posed by changes in the global environment. Gore first looks at evidence of risk in the environment: historical aspects of climate and civilization; ozone layer; water; land use; food supply; waste disposal. In Part II different aspects of our current approaches to the environment are described: politics; economics; technology; social problems; environmentalism of the human spirit. Finally in Part III, Gore presents his approach to the global environmental crisis, first presenting a section about a global sense of responsibility and purpose and then describing his ideas for A Global Marshal Plan. 169 refs., 4 figs.

Gore, A.

1992-01-01

31

Earth in the balance - ecology and the human spirit  

International Nuclear Information System (INIS)

This book by Senator Albert Gore presents a global prospective on the environmental crisis facing the Earth. The chapters are framed in the twin ideas of the threat posed by human civilization to the global environment and the threat to human civilization posed by changes in the global environment. Gore first looks at evidence of risk in the environment: historical aspects of climate and civilization; ozone layer; water; land use; food supply; waste disposal. In Part II different aspects of our current approaches to the environment are described: politics; economics; technology; social problems; environmentalism of the human spirit. Finally in Part III, Gore presents his approach to the global environmental crisis, first presenting a section about a global sense of responsibility and purpose and then describing his ideas for A Global Marshal Plan. 169 refs., 4 figs

1992-01-01

32

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

33

Dual shell pressure balanced reactor vessel. Final project report  

Energy Technology Data Exchange (ETDEWEB)

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&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).

Robertus, R.J.; Fassbender, A.G.

1994-10-01

34

How reliable are latitudinal energy balance models for habitability calculations when using Earth's radiative properties?  

Science.gov (United States)

Exoplanet habitability studies are often performed using simple energy balance models (EBMs), which rely on an understanding of a planet's radiative properties. However, knowledge of these properties is currently limited. Here, I use Earth as a testbed for examining habitability and model uncertainty in a diffusive latitudinal EBM. Using an empirical approach, I parametrize Earth's radiative properties - top of atmosphere albedo and outgoing infrared radiation - as a function of surface temperature, using measurements from the NASA Clouds and Earth's Radiant Energy System instruments. When using surface temperature to construct these functions, a bias analysis shows only small global biases of 3 and - 0.3 W m-2 are introduced for the albedo and infrared functions, respectively. I also show there is a very fine balance between Earth's incoming solar and outgoing infrared radiation in the observational data, which is substantially smaller than previously assumed in this model. Using observationally derived radiative functions for an Earth-like planet, the snowball transition can be determined within a semimajor axis of ˜3 per cent, with a structural uncertainty of ˜2 per cent in the radiative function construction. This work shows that diffusive EBMs can be successfully used to identify habitable exo-Earths within ˜3 per cent if the radiative properties are known.

Gilmore, James B.

2014-05-01

35

Anomalous high pressure behaviour in nanosized rare earth sesquioxides  

International Nuclear Information System (INIS)

We report Raman spectroscopic studies of the nanosized rare earth sesquioxides, namely yttrium sesquioxide (Y2O3), gadolinium sesquioxide (Gd2O3) and samarium sesquioxide (Sm2O3), under high pressure. The samples were characterized using x-ray diffraction, Raman spectroscopy and atomic force microscopy at atmospheric pressures. Y2O3 and Gd2O3 were found to be cubic at ambient, while Sm2O3 was found to be predominantly cubic with a small fraction of monoclinic phase. The strongest Raman peaks are observed at 379, 344 and 363 cm-1, respectively, for Y2O3, Sm2O3 and Gd2O3. All the samples were found to be nanosized with 50-90 nm particle sizes. The high pressures were generated using a Mao-Bell type diamond anvil cell and a conventional laser Raman spectrometer is used to monitor the pressure-induced changes. Y2O3 seems to undergo a crystalline to partial amorphous transition when pressurized up to about 19 GPa, with traces of hexagonal phase. However, on release of pressure, the hexagonal phase develops into the dominant phase. Gd2O3 is also seen to develop into a mixture of amorphous and hexagonal phases on pressurizing. However, on release of pressure Gd2O3 does not show any change and the transformation is found to be irreversible. On the other hand, Sm2O3 shows a weakening of cubic phase peaks while monoclinic phase peaks gain intensity up to about a pressure of 6.79 GPa. However, thereafter the monoclinic phase peaks also reduce in intensity and mostly disordering sets in which does not show significant reversal as the pressure is released. The results obtained are discussed in detail

2008-03-19

36

Phase transitions in rare earth tellurides under pressure.  

Science.gov (United States)

Using first-principles calculations we have studied the valence and structural transitions of the rare earth monotellurides RTe (R = Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb) under pressure. The self-interaction corrected local spin-density approximation is used to establish the ground state valence configuration as a function of volume for the RTe in both the NaCl (B1) and CsCl (B2) structures. We find that in ambient conditions all the RTe are stabilized in the B1 structure. A trivalent (R(3+)) rare earth ground state is predicted for the majority of the RTe, with the exception of SmTe, EuTe, DyTe, TmTe and YbTe, where the fully localized divalent (R(2+)) rare earth configuration is found to be energetically most favourable. Under pressure, the trivalent RTe undergo structural transitions to the B2 structure without associated valence transition. The divalent RTe on the other hand are characterized by a competition between the structural and electronic degrees of freedom, and it is the degree of f-electron delocalization that determines the sequence of phase transitions. In EuTe and YbTe, where respectively the half-filled and filled shells result in a very stable divalent configuration, we find that it is the structural B1 ? B2 transition that occurs first, followed by the R(2+) ? R(3+) valence transition at even higher pressures. In SmTe, DyTe and TmTe, the electronic transition occurs prior to the structural transition. With the exception of YbTe, the calculated transition pressures are found to be in good agreement with experiment. PMID:24934628

Petit, L; Svane, A; Lüders, M; Szotek, Z; Vaitheeswaran, G; Kanchana, V; Temmerman, W M

2014-07-01

37

Balancing the books – a statistical theory of prospective budgets in Earth System science  

Directory of Open Access Journals (Sweden)

Full Text Available An honest declaration of the error in a mass, momentum or energy balance, ?, simply raises the question of its acceptability: 'At what value of ? is the attempted balance to be rejected?' Answering this question requires a reference quantity against which to compare ?. This quantity must be a mathematical function of all the data used in making the balance. To deliver this function, a theory grounded in a workable definition of acceptability is essential. A distinction must be drawn between a retrospective balance and a prospective budget in relation to any natural space-filling body. Balances look to the past; budgets look to the future. The theory is built on the application of classical sampling theory to the measurement and closure of a prospective budget. It satisfies R.A. Fisher's 'vital requirement that the actual and physical conduct of experiments should govern the statistical procedure of their interpretation'. It provides a test, which rejects, or fails to reject, the hypothesis that the closing error on the budget, when realised, was due to sampling error only. By increasing the number of measurements, the discrimination of the test can be improved, controlling both the precision and accuracy of the budget and its components. The cost-effective design of such measurement campaigns is discussed briefly. This analysis may also show when campaigns to close a budget on a particular space-filling body are not worth the effort for either scientific or economic reasons. Other approaches, such as those based on stochastic processes, lack this finality, because they fail to distinguish between different types of error in the mismatch between a set of realisations of the process and the measured data. Keywords: balance, budget, sampling, hypothesis test, closing error, Earth System

J. P. O'Kane

2003-01-01

38

Anomalous high pressure behaviour in nanosized rare earth sesquioxides  

Energy Technology Data Exchange (ETDEWEB)

We report Raman spectroscopic studies of the nanosized rare earth sesquioxides, namely yttrium sesquioxide (Y{sub 2}O{sub 3}), gadolinium sesquioxide (Gd{sub 2}O{sub 3}) and samarium sesquioxide (Sm{sub 2}O{sub 3}), under high pressure. The samples were characterized using x-ray diffraction, Raman spectroscopy and atomic force microscopy at atmospheric pressures. Y{sub 2}O{sub 3} and Gd{sub 2}O{sub 3} were found to be cubic at ambient, while Sm{sub 2}O{sub 3} was found to be predominantly cubic with a small fraction of monoclinic phase. The strongest Raman peaks are observed at 379, 344 and 363 cm{sup -1}, respectively, for Y{sub 2}O{sub 3}, Sm{sub 2}O{sub 3} and Gd{sub 2}O{sub 3}. All the samples were found to be nanosized with 50-90 nm particle sizes. The high pressures were generated using a Mao-Bell type diamond anvil cell and a conventional laser Raman spectrometer is used to monitor the pressure-induced changes. Y{sub 2}O{sub 3} seems to undergo a crystalline to partial amorphous transition when pressurized up to about 19 GPa, with traces of hexagonal phase. However, on release of pressure, the hexagonal phase develops into the dominant phase. Gd{sub 2}O{sub 3} is also seen to develop into a mixture of amorphous and hexagonal phases on pressurizing. However, on release of pressure Gd{sub 2}O{sub 3} does not show any change and the transformation is found to be irreversible. On the other hand, Sm{sub 2}O{sub 3} shows a weakening of cubic phase peaks while monoclinic phase peaks gain intensity up to about a pressure of 6.79 GPa. However, thereafter the monoclinic phase peaks also reduce in intensity and mostly disordering sets in which does not show significant reversal as the pressure is released. The results obtained are discussed in detail.

Dilawar, Nita; Varandani, Deepak; Mehrotra, Shalini; Bandyopadhyay, Ashis K [Pressure and Vacuum Standards, National Physical Laboratory, Dr K S Krishnan Road, New Delhi 110012 (India); Poswal, Himanshu K; Sharma, Surinder M [High Pressure Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

2008-03-19

39

Contact and pressure balance structures in two-fluid cosmic-ray hydrodynamics  

Science.gov (United States)

The role of cosmic-ray-modified contact discontinuities and pressure balance structures in two-fluid cosmic-ray hydrodynamics in one Cartesian space dimension are investigated by means of analytic and numerical solution examples, as well as by weakly nonlinear asymptotics. The fundamental wave modes of the two-fluid cosmic-ray hydrodynamic equations in the long-wavelength limit consist of the backward and forward propagating cosmic-ray-modified sound waves, with sound speed dependent on both the cosmic-ray and thermal gas pressures; the contact discontinuity; and a pressure balance mode in which the sum ofthe cosmic ray and thermal gas pressure perturbations is zero. The pressure balance mode, like the contact discontinuity is advected with the background flow. The interaction of the pressure balance mode with the contact discontinuity is investigated by means of the method of multiple scales. The thermal gas and cosmic-ray pressure perturbations satisfy a linear diffusion equation, and entropy perturbations arising from nonisentropic initial conditions for the thermal gas are frozen into the fluid. The contact discontinuity and pressure balance eigenmodes both admit nonzero perturbations in the thermal gas, whereas the cosmic-ray-modified sound waves are isentropic. The total entropy perturbation is shared between the contact discontinuity and pressure balance eigenmodes, and examples are given in which there is a transfer of entropy between the two modes. In particular, N-wave type density disturbances are obtained which arise as a result of the entropy transfer between the two modes. A weakly nonlinear geometric optics perturbation expansion is used to study the long timescale evolution of the short-wavelength entropy wave and the thermal gas sound waves in a slowly varying, large-scale background flow. The weakly nonlinear geometric optics expansion is also used to generalize previous studies of squeezing instability for short-wavelength sound waves in the two fluid model, by including a weakly nonlinear wave steepening term that leads to shock formation, as well as the effect of long time and space dependence of the background flow. Implications of cosmic-ray-modified pressure balance structures and contact discontinuities in models of the interaction of traveling interplanetary shocks and compression and rarefraction waves with the solar wind termination shock are briefly discussed.

Webb, G. M.; Brio, M.; Zank, G. P.; Story, T.

1995-01-01

40

Experimental and analytical study on earth pressure of an embedded building model during earthquakes  

International Nuclear Information System (INIS)

The objective of this paper is to describe the characteristics of earth pressure during earthquakes for an embedded building model, revealed form earthquake observation and simulation analyses. This paper reports on a study in which the earth pressure records during earthquakes were investigated and were simulated by two and three-dimensional FEM

1989-08-14

 
 
 
 
41

Earth radiation balance as observed and represented in CMIP5 models  

Science.gov (United States)

The genesis and evolution of Earth's climate is largely regulated by the Earth radiation balance. Despite of its key role in the context of climate change, substantial uncertainties still exist in the quantification of the magnitudes of its different components, and its representation in climate models. While the net radiative energy flows in and out of the climate system at the top of atmosphere are now known with considerable accuracy from new satellite programs such as CERES and SORCE, the energy distribution within the climate system and at the Earth's surface is less well determined. Accordingly, the magnitudes of the components of the surface energy balance have recently been controversially disputed, and potential inconsistencies between the estimated magnitudes of the global energy and water cycle have been emphasized. Here we summarize this discussion as presented in Chapter 2.3 of the 5th IPCC assessment report (AR5). In this context we made an attempt to better constrain the magnitudes of the surface radiative components with largest uncertainties. In addition to satellite observations, we thereby made extensive use of the growing number of surface observations to constrain the radiation balance not only from space, but also from the surface. We combined these observations with the latest modeling efforts performed for AR5 (CMIP5) to infer best estimates for the global mean surface radiative components. Our analyses favor global mean values of downward surface solar and thermal radiation near 185 and 342 Wm-2, respectively, which are most compatible with surface observations (Wild et al. 2013). These estimates are on the order of 10 Wm-2 lower and higher, respectively, than in some of the previous global energy balance assessments, including those presented in previous IPCC reports. It is encouraging that these estimates, which make full use of the information contained in the surface networks, coincide within 2 Wm-2 with the latest satellite-derived estimates (Kato et al. 2013), which are completely independently determined. This enhances confidence in these recent surface flux estimates. IPCC AR5 further presents increasing evidence from direct observations that the surface radiative fluxes undergo significant changes on decadal timescales, not only in their thermal components as expected from the increasing greenhouse effect, but also in the amount of solar radiation that reaches the Earth surface. In the thermal range, surface observations suggest an overall increase of downward thermal radiation in line with latest projections from the CMIP5 models and expectations from an increasing greenhouse effect. On the other hand the strong decadal changes in surface solar radiation seen in the observations ("dimming/brightening") are not fully captured by current climate models. These decadal changes in surface solar radiation may largely affect various aspects of climate change. Selected related references: Hartmann, D.L., A.M.G. Klein Tank, M. Rusticucci, L. Alexander, S. Brönnimann, Y. Charabi, F. Dentener, E. Dlugokencky, D. Easterling, A. Kaplan, B. Soden, P. Thorne, M. Wild and P.M. Zhai, 2013: Observations: Atmosphere and Surface. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. Kato, S., Loeb, N.G., Rose, F.G., Doelling, D.R., Rutan, D.A., Caldwell, T.E., Yu, L.S, and Weller, R.A., 2013: Surface irradiances consistent with CERES-derived top-of-atmosphere shortwave and longwave irradiances. Journal of Climate 26 (9):2719-2740. doi:Doi 10.1175/Jcli-D-12-00436.1 Wild, M., 2012: New Directions: A facelift for the picture of the global energy balance. Atmospheric Environment, 55, 366-367. Wild, M. 2012: Enlightening Global Dimming and Brightening. Bull. Amer. Meteor. Soc., 93, 27-37, d

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

2014-05-01

42

A balanced-pressure relief valve fur fuel injection systems. Gleichdruckentlastungsventil fuer Kraftstoffeinspritzanlagen  

Energy Technology Data Exchange (ETDEWEB)

The proposed balanced-pressure relief valve is intended for insertion into forced fuel pipes of internal combustion fuel injection systems between injection pump and injection nozzle. The balanced-pressure relief valve is provided with a pressure valve element (1) whose body (5) holds a case sleeve (6) fixed due to radial deformation. The case sleeve houses a relief valve with valve seat (12), relief valve element (11) and helical spring (9). The radial deformation of the case sleeve (6) also fixes the seat (12). The case sleeve (6) is made of a softer, workable material while the seat (12), the valve body (5) and the relief valve element (11) are made of a hard material.

Ritter, E.

1990-08-23

43

Validation of a soil water balance model using soil water content and pressure head data  

Science.gov (United States)

The validation of soil water balance models and the evaluation of the quality of the model predictions at field-scale require time-series of in situ measured model outputs. In our study, we have validated such a model using a 6-year period with time-series of automatically recorded, daily volumetric soil water contents measured with the time-domain reflectometry with intelligent microelements (TRIME) method and daily pressure heads measured with tensiometers. The comparisons of simulated with measured soil water contents and pressure heads were analysed using the modelling efficiency index (IA) and the square root of the mean square error (RMSE) in order to evaluate the prediction quality of the model. In our study, IA and RMSE, obtained either from the comparison of simulated with measured soil water contents or the comparison of calculated with observed pressure heads, in some cases lead to different results regarding the evaluation of the simulation quality of the soil water balance model. For example, a good fit between simulated and observed soil water contents does not necessarily result in a comparably good fit between the corresponding calculated and measured pressure heads. Therefore, a combined use of both measurement techniques, which takes into account their respective advantages and disadvantages, gives a more complete overview on the simulation quality of the soil water balance model than the single use of one of those techniques.

Wegehenkel, Martin

2005-04-01

44

Mounting Pressures on Planet Earth. A Four-Part Bicentennial Symposium Series.  

Science.gov (United States)

Detailed are the proceedings of the 1976 Bicentennial Symposium Series held under the general title of Mounting Pressures on Planet Earth. This event, co-sponsored by the Maryland State Department of Education and the NASA Goddard Space Flight Center, brought together researchers and educators to discuss solutions to the Earth's problems. The…

Anderton, David A., Ed.

45

Long term reduction in sodium balance: possible additional mechanism whereby nifedipine lowers blood pressure.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

OBJECTIVE--To assess the changes in sodium excretion and sodium balance after withdrawal of long term nifedipine. DESIGN--Single blind, placebo controlled study in patients receiving fixed sodium and potassium intakes. SETTING--Blood pressure unit of a teaching hospital in south London. PATIENTS--Eight patients with mild to moderate uncomplicated essential hypertension who had been taking nifedipine 20 mg twice daily for at least six weeks. INTERVENTIONS--Withdrawal of nifedipine and replacem...

Pevahouse, J. B.; Markandu, N. D.; Cappuccio, F. P.; Buckley, M. G.; Sagnella, G. A.; Macgregor, G. A.

1990-01-01

46

A novel pneumatic micropipette aspiration method using a balance pressure model  

Science.gov (United States)

This paper presents a novel micropipette aspiration (MA) method based on a common pneumatic micro-injection system. This method is the first to quantify the influence of capillary effect on aspiration pressure using a balance pressure model, and in return, uses the capillary effect to quantify the aspiration pressure. Subsequently, the seal between the cell and the micropipette is detected to judge and exclude the ineffective MA attempts. The rationality of the balance pressure model is validated by the designed micropipette-filling experiments. Through applied to elasticity-determination of the cells with different sizes, the feasibility and versatility of this MA method are proved. With abilities to quantify aspiration pressures and detect the seam between the cell and the micropipette, our method is expected to advance the application of the commercial pneumatic injector in the MA of cells. Moreover, with the quantified volume of the liquid entering into the micropipette during MA process, our method also has a potential applicability to the study of the permeability of the cell membrane in the future.

Zhao, Qili; Wu, Ming; Cui, Maosheng; Qin, Yanding; Yu, Jin; Sun, Mingzhu; Zhao, Xin; Feng, Xizeng

2013-12-01

47

Blood pressure and calcium balance in the Wistar-Kyoto rat.  

Science.gov (United States)

Recent investigations in human and experimental hypertension have characterized previously unrecognized abnormalities of calcium homeostasis. Data from human and animal studies have indicated that adequate dietary calcium intake may be an important determinant for the development of high blood pressure. Since dietary calcium supplementation has been shown to attenuate the hypertension of the spontaneously hypertensive rat (SHR), the present study was undertaken to assess the effect of dietary calcium intake on the blood pressure of the Wistar-Kyoto rat (WKY), the normotensive genetic control for the SHR. One of three levels of dietary calcium was fed to 36 WKYs beginning at eight to 10 weeks of age (WOA) through 34 WOA. Throughout the period of observation, the WKYs stratified inversely with their level os dietary calcium (p less than .001), i.e. rats fed the lowest level of calcium had the highest blood pressure. WKYs on the high calcium diet experienced an attenuation of their blood pressure with increasing age and dietary calcium intake. These salutary blood pressure effects of dietary calcium were independent of growth and urinary sodium excretion of the rats. Serum ionized calcium (Ca++) increased in the high calcium diet WKYs and appeared to be associated with the blood pressure reduction. The results suggest that calcium intake must be assessed in experimental models of hypertension and that the state of calcium balance is a possibly important determinant of blood pressure regulation. PMID:7070225

McCarron, D A

48

Experiences of dynamic balancing of pressure for control of fire in Jharia, Raniganj and Karapura coalfields  

Energy Technology Data Exchange (ETDEWEB)

The importance of the Pressure Balancing technique for controlling fires in underground coal mines has over the years, undergone a number of refinements including development and introduction of devices for automatic correction of pressure imbalance caused by diurnal variation of pressure or changes in the ventilation network of amine. Despite these advancements, the technique failed to make any positive impact in Indian coal mines for various reasons. In mid eighties the concept of Dynamic Balancing of Pressure was introduced by Central Mining Research Institute, Dhanbad and since then the method has been successfully applied in more than dozen mines spread over three major coalfields of India. The technique has now gained wide acceptance in the country and is being routinely used for tackling fire in underground mines. This paper describes the case studies covering three major coalfields of the country where this method was successfully applied for controlling fires. A brief background with limitations of the method is also outlined. 7 refs., 6 figs., 8 tabs.

Ahmad, I.; Sahay, N.; Singh, R.P.; Verma, S.M.; Bhowmick, B.C.; Dhar, B.B. [Central Mining Research Institute, Dhanbad (India)

1997-12-31

49

Investigation of saturated vapor pressure in iron chloride-rare earth chloride systems  

International Nuclear Information System (INIS)

Experimental data on boiling temperatures under different pressures in FeCl2-MCl3 (M=La, Ce, Pr, Nd, Gd) systems are presented. Temperature dependence of saturated vapour pressure for the mentioned systems has been established, normal boiling temperatures and evaporation enthalpies have been calculated. Isotherms (1250, 1200, 1150 K) of vapour pressure for different compositions are given on the basis of calculations for ideal solutions and experimental data demonstrating a good agreement. Conclusions are made on interaction types in systems of iron dichloride-chlorides of alkali, alkali earth and rare earth metals

1982-01-01

50

High Pressure Phase Transformations in Heavy Rare Earth Metals and Connections to Actinide Crystal Structures  

International Nuclear Information System (INIS)

High-pressure studies have been performed on heavy rare earth metals Terbium (Tb) to 155 GPa and Holmium (Ho) to 134 GPa in a diamond anvil cell at room temperature. The following crystal structure sequence was observed in both metals hcp ? Sm-type ? dhcp ? distorted fcc (hR-24) ? monoclinic (C2/m) with increasing pressure. The last transformation to a low symmetry monoclinic phase is accompanied by a volume collapse of 5 % for Tb at 51 GPa and a volume collapse of 3 % for Ho at 103 GPa. This volume collapse under high pressure is reminiscent of f-shell delocalization in light rare earth metal Cerium (Ce), Praseodymium (Pr), and heavy actinide metals Americium (Am) and Curium (Cm). The orthorhombic Pnma phase that has been reported in Am and Cm after f-shell delocalization is not observed in heavy rare earth metals under high pressures. (authors)

2008-03-24

51

EXPERIMENTAL STUDY ON WATER BALANCE IN A NEGATIVE PRESSURE DIFFERENCE IRRIGATION SYSTEM  

Science.gov (United States)

Negative pressure difference irrigation (NPDI) is considered to be an attractive mode of irrigation because water use efficiency in this case is higher than that in conventional irrigation methods such as basin irrigation, furrow irrigation and sprinkler irrigation. In order to investigate the water balance in a NPDI system, experiments involving the use of a soil column, porous pipe and water reservoir were carried out in a temperature and humidity controlled room. The evaporation (Meva), supplied water (Msup), soil water storage (Msoil), wetted soil surface area and configuration of the wetted soil around the porous pipe were determined for three different negative pressures. Empirical equations were proposed for the calculation of Meva and Msoil. The proposed simple model could well reproduce the temporal variations in Meva and Msoil. With a decrease in the negative pressure, the water use efficiency increased and was in the range of 0.92 to 0.97.

Moniruzzaman, S. M.; Fukuhara, Teruyuki; Terasaki, Hiroaki

52

Dual Shell Pressure Balanced Reactor Vessel cooperative research and development agreement with Innotek, Inc., Final report  

Energy Technology Data Exchange (ETDEWEB)

The Department of Energy`s Office of Energy Research (OER) has 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. This document details a cooperative research and development agreement 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&D 100 award-winning technology, Sludge-to-oil Reactor System (STORS), originally developed through funding by OER.

Robertus, R.J.; Fassbender, A.G.; Deverman, G.S.

1995-04-01

53

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.

2013-11-01

54

A planar, pressure-balanced, reconnecting structure embedded in a small solar wind transient  

Science.gov (United States)

We describe a ~4 hour-long solar wind transient observed by the Wind spacecraft, in which is embedded a pressure-balanced structure. Minimum variance analysis on high resolution (~11 Hz) magnetic field data shows it to be planar to an excellent approximation (ratio of intermediate-to-minimum eigenvalues = 83). The structure starts with a very sharp discontinuity whose orientation coincides within four degrees with that of the structure itself. We find that this discontinuity has a bifurcated magnetic field and plasma flow structure. There is also a velocity depression coextensive with it. Applying a tangential stress balance test (Walén relation) to the discontinuity, we find good agreement of predictions with observations. We show directly the presence of two Alfvén waves propagating in opposite directions. The observation is consistent with the presence of a reconnection region in a hitherto unexplored configuration within a small solar wind transient.

Farrugia, C. J.; Yu, W.; Galvin, A. B.; Vasquez, B. J.; Kucharek, H.; Lugaz, N.; Torbert, R. B.; Szabo, A.; Lin, R. P.; Ogilvie, K. W.

2013-06-01

55

Earth pressure analysis of filled materials by distinct element method using ellipse model  

Energy Technology Data Exchange (ETDEWEB)

The effect of the shape and arrangement of filled materials such as boulder in steel-made structures on their earth pressure was studied. Ellipse model elements were substituted for the filled materials for analyzing the earth pressure by distinct element method, the contact force between two ellipse elements was calculated by Newton{prime}s method, and the difference equation of motion for the ellipse model was numerically solved by Euler{prime}s method. The earth pressure was thus obtained by summing up the contact forces applied to a steel wall. As the results of three numerical examples, the coefficient of earth pressure was 0.2-0.3 in the arrangement with flat shape elements, 0.6 for circle shape ones, and 1.2-2.0 for longitudinal shape ones. As subjected to a horizontal force from a back wall, the earth pressure in the flat arrangement of elements was headed diagonally toward the bottom of structures, resulting in the very efficient arrangement because of the smaller resistance on the upper part of a front wall. 7 refs., 10 figs.

Katsuki, S.; Ishikawa, N. (National Defence Academy, Kanagawa (Japan))

1991-07-15

56

High pressure Earth storable rocket technology program: Basic program  

Science.gov (United States)

The HIPES Program was conducted for NASA-LeRC by TRW. The Basic Program consisted of system studies, design of testbed engine, fabrication and testing of engine. Studies of both pressure-fed and pump-fed systems were investigated for N2O4 and both MMH and N2H4 fuels with the result that N2H4 provides the maximum payload for all satellites over MMH. The higher pressure engine offers improved performance with smaller envelope and associated weight savings. Pump-fed systems offer maximum payload for large and medium weight satellites while pressure-fed systems offer maximum payload for small light weight satellites. The major benefits of HIPES are high performance within a confined length maximizing payload for lightsats which are length (volume) constrained. Three types of thrust chambers were evaluated -- Copper heatsink at 400, 500 and 600 psia chamber pressures for performance/thermal; water cooled to determine heat absorbed to predict rhenium engine operation; and rhenium to validate the concept. The HIPES engine demonstrated very high performance at 50 lbf thrust (epsilon = 150) and Pc = 500 psia with both fuels: Isp = 337 sec using N2O4-N2H4 and ISP = 327.5 sec using N2O4-MMH indicating combustion efficiencies greater than 98%. A powder metallurgy rhenium engine demonstrated operation with high performance at Pc = 500 psia which indicated the viability of the concept.

Chazen, M. L.; Sicher, D.; Huang, D.; Mueller, T.

1995-01-01

57

Compressor, pressure control, and quantitative balancing plant (VDM) Scharenstetten. Verdichter-, Druckregel- und Mengenbilanzierungsanlage (VDM) Scharenstetten  

Energy Technology Data Exchange (ETDEWEB)

After a planning and construction period of 3 1/2 years, the Gasversorgung Sueddeutschland GmbH (GVS), Stuttgart, commissioned a modern natural-gas compressor station on the Schwaebische Alb at Scharenstetten, Northwest of city of Ulm in September 1988. This plant also contains a plant for pressure control and quantitative balancing and allows GVS to secure the growing energy demand in Baden-Wuerttemberg and of the neighbouring Vorarlberg, Liechtenstein and Eastern Switzerland in the long term. The author presents in detail its planning and construction. (orig.).

Kuelzer, J. (Gasversorgung Sueddeutschland GmbH, Stuttgart (Germany, F.R.))

1990-06-01

58

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

International Nuclear Information System (INIS)

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

59

Nonlinear pressure effects in superconducting rare earth-iron-silicides  

International Nuclear Information System (INIS)

The superconducting transition temperatures (Tsub(c)) of RE_2Fe_3Si_5 (RE = Sc, Y, Lu) vary in a nonlinear fashion under hydrostatic pressure up to 20 kbar. For the Sc and Lu compounds Tsub(c) decreases at an average rate of -7x10"-"5K bar"-"1, while Tsub(c) of Y_2Fe_3Si_5 increases rapidly (33x10"-"5K bar"-"1) and passes through a maximum whose value is twice that at ambient pressure. The results are compared with the effects of volume contraction across the series (Ysub(1-x)Lusub(x))_2Fe_3Si_5 and (Ysub(1-x)Dysub(x))_2Fe_3Si_5. (Auth.)

1981-08-14

60

High Pressure, Earth-Storable Rocket Technology. Volume 2  

Science.gov (United States)

The effect of elevated chamber pressure on combustion efficiency and heat transfer has been determined at the 100 lbf (445 N) thrust level for nitrogen tetroxide propellants. Measurements were made up to 500 psia (3.45 Mpa) with testbed hardware; tests at 100 psia (0.690 MPa) and 250 psia (1.72 MPa) were made with radiation-cooled rhenium chambers. The first task of the program served to determine desirable thruster applications and operating conditions: high total impulse, i.e. communication satellite or spacecraft bus axial engines, at chamber pressures up to 250 psia (1.72 MPa) pressure-fed, or up to 500 psia (3.45 MPa) pump-fed. The hardware modifications and testing required to obtain the data were determined in Task 2, which included design-support hot fire tests; supplemental hardware, including a 250 psia (1.72 MPa) Pc rhenium chamber and a 20% fuel-film cooled platelet injector was fabricated in Task 3. Testing showed that satisfactory operation of Ir-Re radiation chambers is assured at pressures up to 250 psia and may be possible up to 500. The heat transfer data obtained show good correlation with throat Reynolds number and are generally under values given by the simplified Bartz equation; chambers equilibrium temperatures match predicted values. Preliminary optimization of trip configuration and mixture ratio were made; Isp performance from thrust measurements was within 1% of predicted values. Stability, compatibility, and front-end thermal management were determined to be satisfactory.

Jassowski, D. M.

1997-01-01

 
 
 
 
61

High Pressure, Earth-Storable Rocket Technology. Volume 1  

Science.gov (United States)

The effect of elevated chamber pressure on combustion efficiency and heat transfer has been determined at the 100 lbf (445 N) thrust level for nitrogen tetroxide propellants. Measurements were made up to 500 psia (3.45 MPa) with testbed hardware; tests at 100 psia (0.690 MPa) and 250 psia (1.72 MPa) were made with radiation-cooled rhenium chambers. The first task of the program served to determine desirable thruster applications and operating conditions: high total impulse, i.e., communication satellite or spacecraft bus axial engines, at chamber pressures up to 250 psia (1.72 MPa) pressure-fed, or up to 500 psia (3.45 MPa) pump-fed. The hardware modifications and testing required to obtain the data were determined in Task 2, which included design-support hot fire tests; supplemental hardware, including a 250 psia (1.72 MPa) Pc rhenium chamber and a 20% fuel-film cooled platelet injector was fabricated in Task 3. Testing showed that satisfactory operation of Ir-Re radiation chambers is assured at pressures up to 250 psia and may be possible up to 500. The heat transfer data obtained show good correlation with throat Reynolds number and are generally under values given by the simplified Bartz equation; chambers equilibrium temperatures match predicted values. Preliminary optimization of trip configuration and mixture ratio were made; Isp performance from thrust measurements was within 1% of predicted values. Stability, compatibility, and front-end thermal management were determined to be satisfactory.

Jassowski, D. M.

1997-01-01

62

Advanced Pressure Coring System for Deep Earth Sampling (APRECOS)  

Science.gov (United States)

Nowadays the recovery of cores from boreholes is a standard operation. However, during that process the mechanical, physical, and chemical properties as well as living conditions for microorganisms are significantly altered. In-situ sampling is one approach to overcome the severe scientific limitations of conventional, depressurized core investigations by recovering, processing, and conducting experiments in the laboratory, while maintaining unchanged environmental parameters. The most successful equipment today is the suite of tools developed within the EU funded projects HYACE (Hydrate Autoclave Coring Equipment) and HYACINTH (Deployment of HYACE tools In New Tests on Hydrates) between 1997 and 2005. Within several DFG (German Research Foundation) projects the Technical University Berlin currently works on concepts to increase the present working pressure of 250 bar as well as to reduce logistical and financial expenses by merging redundant and analogous procedures and scaling down the considerable size of key components. It is also proposed to extend the range of applications for the wireline rotary pressure corer and the sub-sampling and transfer system to all types of soil conditions (soft to highly-consolidated). New modifications enable the tools to be used in other pressure related fields of research, such as unconventional gas exploration (coal-bed methane, tight gas, gas hydrate), CO2 sequestration, and microbiology of the deep biosphere. Expedient enhancement of an overall solution for pressure core retrieval, process and investigation will open the way for a complete on-site, all-purpose, in-situ equipment. The advanced assembly would allow for executing the whole operation sequences of coring, non-destructive measurement, sub-sampling and transfer into storage, measurement and transportation chambers, all in sterile, anaerobic conditions, and without depressurisation in quick succession. Extensive post-cruise handling and interim storage would be dispensable. The complete core processing and preparation of in-situ sample sections for worldwide shipping could be conducted within hours after retrieval.

Anders, E.; Rothfuss, M.; Müller, W. H.

2009-04-01

63

Removal of barometric pressure effects and earth tides from observed water levels.  

Science.gov (United States)

The effects of barometric pressure and earth tide changes are often observed in ground water level measurements. These disturbances can make aquifer test interpretation difficult by masking the small changes induced by aquifer testing at late times and great distances. A computer utility is now available that automatically removes the effects of barometric pressure and earth tides from water level observations using regression deconvolution. This procedure has been shown to remove more noise then traditional constant barometric efficiency techniques in both confined and unconfined aquifers. Instead of a single, instantaneous barometric efficiency, the procedure more correctly accounts for the lagged responses caused by barometric pressure and earth tide changes. Simultaneous measurements of water levels (or total heads) and nearby barometric pressures are required. As an additional option, the effects of earth tides can also be removed using theoretical earth tides. The program is demonstrated for two data sets collected at the Waste Isolation Pilot Plant, Carlsbad, New Mexico. The program is available free by request at http://www.hydrology.uga.edu/tools.html. PMID:17257346

Toll, Nathanial J; Rasmussen, Todd C

2007-01-01

64

High pressure phase transitions in the rare earth metal erbium to 151 GPa  

International Nuclear Information System (INIS)

High pressure x-ray diffraction studies have been performed on the heavy rare earth metal erbium (Er) in a diamond anvil cell at room temperature to a pressure of 151 GPa and Er has been compressed to 40% of its initial volume. The rare earth crystal structure sequence hcp?Sm type?dhcp?distorted fcc (hcp: hexagonal close packed; fcc: face centered cubic; dhcp: double hcp) is observed in Er below 58 GPa. We have carried out Rietveld refinement of crystal structures in the pressure range between 58 GPa and 151 GPa. We have examined various crystal structures that have been proposed for the distorted fcc (dfcc) phase and the post-dfcc phase in rare earth metals. We find that the hexagonal hR 24 structure is the best fit between 58 and 118 GPa. Above 118 GPa, a structural transformation from hR 24 phase to a monoclinic C 2/m phase is observed with a volume change of - 1.9%. We have also established a clear trend for the pressure at which a post-dfcc phase is formed in rare earth metals and show that there is a monotonic increase in this pressure with the filling of 4f shell.

2011-08-10

65

Interstitial pressure dependence of the thermal conductivity of some rare earth oxide powders  

International Nuclear Information System (INIS)

Thermal transport properties of powdered materials depend upon interstitial gas pressure. The present study reports the experimental results for the effective thermal conductivity of three rare earth oxide powders viz. yttrium oxide, samarium oxide, and gadolinium oxide, at various interstitial pressures by using transient plane source (TPS) method. A theoretical model is also proposed for the interpretation of the variation of the effective thermal conductivity with interstitial gas pressure. Its validity is found to be good in low pressure range of 45 mm Hg to normal pressure when compared with the experimental results. Also an attempt has been made to calculate the variation of thermal conductivity with interstitial pressure in the high pressure range up to 2 kbar using the proposed model. (author)

1997-09-01

66

Variations in predialytic plasma conductivity in dialysis patients: effect on ionic mass balance and blood pressure.  

Science.gov (United States)

In this study, variations in plasma conductivity (PC), as a surrogate marker of plasma sodium, as well as its relation with intradialytic ionic mass balance (IMB) and blood pressure were assessed in 73 patients. Plasma conductivity and IMB were retrieved on a treatment to treatment basis during a 6-month period. Dialysate sodium concentration was 140 mmol/L. A total of 4070 treatments were analyzed. Mean coefficient of variation for predialytic PC was 1.3%, and mean intraindividual range in predialytic PC measurements during the 6-month follow-up period was 0.9 mS/cm (plasma sodium ? 9 mmol/L). Predialytic PC was related to both diffusive and total IMB (r = 0.91, p blood pressure (r = 0.35; p blood pressure was significantly different between treatments with the lowest and highest predialytic PC (139 ± 24 vs. 147 ± 21 mm Hg; p blood pressure, which might suggest a volume-independent effect of sodium. PMID:21160422

Moret, Karin E; Beerenhout, Charles H; Kooman, Jeroen P

2011-01-01

67

Anthropogenic and natural exergy losses (exergy balance of the Earth's surface and atmosphere)  

International Nuclear Information System (INIS)

Natural exergy losses connected with the absorption of solar radiation by the Earth have been calculated. The exergy income caused by the radiation exchange between the Earth and the cosmic space has also been considered. The exergy losses occurring near the Earth's surface have been distinguished because they represent the most accessible natural resources of exergy. The term 'natural losses of utilizable exergy' has been proposed. These losses have been compared with the anthropogenic ones caused by the activity of humankind. The positive impact of the natural exergy losses has been pointed out: they were a main cause of the formation of the terrestrial natural environment, of the non-renewable natural resources of fuels, and of the generation of stable dissipative structures in form of living beings

2003-09-01

68

The role of pressure solution creep in the ductility of the earth's upper crust  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this review is to characterize the role of pressure solution creep in the ductility of the Earth's upper crust and to describe how this creep mechanism competes and interacts with other deformation mechanisms. Pressure solution creep is a major mechanism of ductile deformation of the upper crust, accommodating basin compaction, folding, shear zone development, and fault creep and interseismic healing. However, its kinetics is strongly dependent on the composition of the rocks (main...

Gratier, Jean-pierre; Dysthe, Dag; Renard, Francois

2013-01-01

69

Service-life limitations in vacuum glazing: A transient pressure balance model  

Energy Technology Data Exchange (ETDEWEB)

Windows constitute a weak link in the building envelope and hence contribute significantly to the heating energy demand. By evacuating the glazing cavity, heat transfer rates two to five times lower than those of gas-filled conventional glazing units are predicted in theory and have been practically confirmed in a few cases. Of central importance to any practical realization of vacuum glazing is the edge-sealing problem because the technology used defines many secondary and tertiary parameters and strongly influences service life. This work establishes a correlation between the sealing method and its effect on the products service life. A cavity pressure balance model is presented, which takes into account four possible sources to the total pressure increase. Using this model a set of critical parameters is defined and the range of tolerable values for each parameter can be extracted. These findings underline the importance of choosing a sealing process, which is carried out in a high-vacuum environment. A possible source of pressure increase not considered in detail so far is the photofragmentation of long-chain organic adsorbate contaminants on the inner glazing surfaces. It was shown that a surface treatment via UV/ozone cleaning reduces the surface concentration of a model surface contaminant sodium dodecyl sulfate (SDS) by approximately 3 orders of magnitude. (author)

Koebel, Matthias M.; Manz, Heinrich; Emanuel Mayerhofer, Karl; Keller, Beat (Swiss Federal Laboratories for Materials Research and Testing, Empa, Ueberlandstrasse 129, CH-8600 Duebendorf, Switzerland.)

2010-06-15

70

Importance of the deep ocean for estimating decadal changes in Earth's radiation balance  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We use control run data from three Met Office Hadley Centre climate models to investigate the relationship between: net top-of-atmosphere radiation balance (TOA), globally averaged sea surface temperature (SST); and globally averaged ocean heat content (OHC) on decadal timescales. All three models show substantial decadal variability in SST, which could easily mask the long-term warming associated with anthropogenic climate change over a decade. Regression analyses are used to estimate the un...

Palmer, Matthew D.; Mcneall, Douglas J.; Dunstone, Nick J.

2011-01-01

71

Energy balance and pressure in the solar transition zone for network and active region features  

International Nuclear Information System (INIS)

The pressure and energy balance in the solar transition zone are determined for about 125 network and active region features from new high spectral (0.06 A) and spatial (1'') resolution extreme-ultraviolet spectra. New plasma diagnostics consisting of Si III line intensity ratios are used to find the electron density N, and pressure P/sub e/ near 3.5 x 104 K, the temperature where Si III is most abundant. The observed Si III line intensity ratios, R (1301/1312) and R (1301/1296), are compared with theoretical calculations for these ratios as functions of density and temperature. From this comparison, electron densities ranging from 2 x 1010 cm-3 at 2000 km above the limb to 10 12 cm-3 in an active region are derived. The energy losses due to radiation are compared with two energy source terms, conductive flux and turbulent energy dissipation. The radiative losses are proportional only to P/sub e/2. However, the divergence of the conductive flux is a function of the fill factor a and the average temperature gradient in the line of sight , and the turbulent energy dissipation is a function of a and P/sub e/. P/sub e/ and can be found from plasma diagnostics and emission line intensities, but values of a must be derived by assuming the spatial extent of the transition zone plasma along the line of sight.In an extreme case a=1 for a plane-parallel homogeneous transition zone, and the divergence of the conductive flux and turbulent energy dissipation balance the radiative losses

1979-10-15

72

High-pressure phase transitions in rare earth metal thulium to 195 GPa  

International Nuclear Information System (INIS)

We have performed image plate x-ray diffraction studies on a heavy rare earth metal, thulium (Tm), in a diamond anvil cell to a pressure of 195 GPa and volume compression V/Vo = 0.38 at room temperature. The rare earth crystal structure sequence, hcp ? Sm-type ? dhcp ? fcc ? distorted fcc, is observed in Tm below 70 GPa with the exception of a pure fcc phase. The focus of our study is on the ultrahigh-pressure phase transition and Rietveld refinement of crystal structures in the pressure range between 70 and 195 GPa. The hexagonal hR- 24 phase is seen to describe the distorted fcc phase between 70 and 124 GPa. Above 124 ± 4 GPa, a structural transformation from hR 24 phase to a monoclinic C 2/m phase is observed with a volume change of - 1.5%. The equation of state data shows rapid stiffening above the phase transition at 124 GPa and is indicative of participation of f-electrons in bonding. We compare the behavior of Tm to other heavy rare-earths and heavy actinide metals under extreme conditions of pressure.

2011-04-20

73

Earth's core-mantle boundary - Results of experiments at high pressures and temperatures  

Science.gov (United States)

Laboratory experiments document that liquid iron reacts chemically with silicates at high pressures (above 2.4 x 10 to the 10th Pa) and temperatures. In particular, (Mg,Fe)SiO3 perovskite, the most abundant mineral of earth's lower mantle, is expected to react with liquid iron to produce metallic alloys (FeO and FeSi) and nonmetallic silicates (SiO2 stishovite and MgSiO3 perovskite) at the pressures of the core-mantle boundary, 14 x 10 to the 10th Pa. The experimental observations, in conjunction with seismological data, suggest that the lowermost 200 to 300 km of earth's mantle, the D-double-prime layer, may be an extremely heterogeneous region as a result of chemical reactions between the silicate mantle and the liquid iron alloy of earth's core. The combined thermal-chemical-electrical boundary layer resulting from such reactions offers a plausible explanation for the complex behavior of seismic waves near the core-mantle boundary and could influence earth's magnetic field observed at the surface.

Knittle, Elise; Jeanloz, Raymond

1991-01-01

74

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

International Nuclear Information System (INIS)

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. (paper)

2013-07-17

75

Between-day reliability of centre of pressure measures for balance assessment in hemiplegic stroke patients  

Science.gov (United States)

Background Stroke patients have impaired postural balance that increases the risk of falls and impairs their mobility. Assessment of postural balance is commonly carried out by recording centre of pressure (CoP) displacements, but the lack of data concerning reliability of these measures compromises their interpretation. The purpose of this study was to investigate the between-day reliability of six CoP-based variables, in order to provide i) reliability data for monitoring postural sway and weight-bearing asymmetry of stroke patients in clinical practice and ii) consistent assessment method of measurement error for applications in physical medicine and rehabilitation. Methods Postural balance of 20 stroke patients was assessed in quiet standing on a force platform, in two sessions, 7 days apart. Six CoP-based variables were collected in eyes open and eyes closed conditions: postural sway was assessed with mean and standart deviation of CoP-velocity, CoP-velocity along the mediolateral and anteroposterior axes, and confidence ellipse area (CEAREA); weight-bearing asymmetry was assessed with mean CoP position along the mediolateral axis (CoPML). The intraclass correlation coefficient (ICC) was used to determine the level of agreement between test-retest. Small real difference (SRD), corresponding to the smallest change that indicates a real improvement for a single individual, was used to determine the extent of measurement error. Results ICCs were satisfactory (>0.9) for all CoP-based variables, except for CEAREA in eyes open condition and CoPML (heteroscedasticity of measurement error distribution, SRD (eyes open/closed conditions) was expressed as a percentage (121/75%) and a ratio (3.68/2.16) obtained after log-antilog procedure. Conclusions In clinical practice, the CoP-based velocity variables should be prefer to CEAREA to assess and monitor postural sway over time in hemiplegic stroke patients. The poor reliability of CoPML compromises its use to assess weight-bearing asymmetry. The procedure we used could be applied in reliability studies concerning other CoP-based variables or other biological variables in the field of physical medicine and rehabilitation.

2014-01-01

76

Earth'  

...Earth's green overshoot 'starts today': NGO | EurActiv EU news & policy debates- across languages - en fr Click here for ... › News Earth's green overshoot 'starts today': NGO -A + A Published 25 September 2009, updated 14 December 2012 Tags sustainable ...consumption and production, sustainable development Today (25 September) marks 'Earth Overshoot Day', after which date humanity begins to live beyond its ecological means for ... Developed by a UK foundation, Earth Overshoot Day marks the day when the world's total ecological footprint equals the biocapacity that nature can regenerate ...

77

Transport coefficients and entropy-scaling law in liquid iron up to Earth-core pressures.  

Science.gov (United States)

Molecular dynamics simulations were applied to study the structural and transport properties, including the pair distribution function, the structure factor, the pair correlation entropy, self-diffusion coefficient, and viscosity, of liquid iron under high temperature and high pressure conditions. Our calculated results reproduced experimentally determined structure factors of liquid iron, and the calculated self-diffusion coefficients and viscosity agree well with previous simulation results. We show that there is a moderate increase of self-diffusion coefficients and viscosity along the melting curve up to the Earth-core pressure. Furthermore, the temperature dependencies of the pair correlation entropy, self-diffusion, and viscosity under high pressure condition have been investigated. Our results suggest that the temperature dependence of the pair correlation entropy is well described by T(-1) scaling, while the Arrhenius law well describes the temperature dependencies of self-diffusion coefficients and viscosity under high pressure. In particular, we find that the entropy-scaling laws, proposed by Rosenfeld [Phys. Rev. A 15, 2545 (1977)] and Dzugutov [Nature (London) 381, 137 (1996)] for self-diffusion coefficients and viscosity in liquid metals under ambient pressure, still hold well for liquid iron under high temperature and high pressure conditions. Using the entropy-scaling laws, we can obtain transport properties from structural properties under high pressure and high temperature conditions. The results provide a useful ingredient in understanding transport properties of planet's cores. PMID:24655191

Cao, Qi-Long; Wang, Pan-Pan; Huang, Duo-Hui; Yang, Jun-Sheng; Wan, Ming-Jie; Wang, Fan-Hou

2014-03-21

78

Magnetic Field Structure of Pressure Balanced Structures from Ulysses High Latitudes Observations  

Science.gov (United States)

Ulysses observations showed that pressure balance structures (PBSs) are a common feature in the high-latitude solar winds near the solar minimum. On the other hand, coronal plumes are common in polar coronal holes near the solar minimum. It is therefore considered that the PBSs would be remnants of plumes. Several detailed studies of the PBSs have been made from Ulysses/SWOOPS observations, but study of their magnetic structures has not yet been done. The study of the magnetic structure is important because previous observations and theoretical models of plumes indicate that they are related to the network activity such as magnetic reconnection on the photosphere. We have investigated the magnetic structures of the PBSs with Ulysses magnetometer and SWOOPS data. We have found that magnetic reversals in radial magnetic field take place while the spacecraft passes through most of the PBSs These magnetic reversals have been interpreted as large amplitude Alfv/'enic fluctuations but our results suggest that Ulysses is also traversing current sheets of plasmoids associated with network activity at the base of plumes.

Yamauchi, Y.; Suess, S. T.; Sakurai, T.; Rose, M. Franklin (Technical Monitor)

2001-01-01

79

Iron under Earth’s core conditions: Liquid-state thermodynamics and high-pressure melting curve from ab initio calculations  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Ab initio techniques based on density functional theory in the projector-augmented-wave implementation are used to calculate the free energy and a range of other thermodynamic properties of liquid iron at high pressures and temperatures relevant to the Earth’s core. The ab initio free energy is obtained by using thermodynamic integration to calculate the change of free energy on going from a simple reference system to the ab initio system, with thermal averages computed by ab initio molecul...

Alfe, D.; Price, G. D.; Gillan, M. J.

2002-01-01

80

Engineering kinematic theory of the contact earth pressure and its application to the static calculation of thin quay walls  

Directory of Open Access Journals (Sweden)

Full Text Available Construction of deep-water thrust berthing structures requires using new and more perfect methods of calculation containing fewer assumptions. A version of the engineering kinematic theory of contact earth pressure in the application to the water-transport and offshore structures was suggested in the article. A dimensionless static “compression – tension” diagram of the soil, presented by curvilinear function, was used in the method. In this case, the displacement of the limit point of the diagram is determined with the account of the plastic deformation modulus in the earth contact point. Practical application of engineering theory was implemented in the proposed method of the mirroring with respect to anchored thin walls. In this method different lateral pressure profiles depending on the rated scheme were used. This method consists in three steps’ loading of anchored wall. The first stage – the normal calculation of the wall in the form of beam loaded by active earth pressure and bearing on the anchor pole and partly on the base ground. The second stage – the anchor reaction and the foundation earth reactive pressure are mirrored in the form of external loads acting on the part of the water area on the beam bearing on the backfill and foundation soil. Third stage – repeating the first external load in the form of the earth pressure profile behind the wall derived in the second calculation step. Suggested calculation as distinct from existing methods, which are using active earth pressure, defines more exactly the strains in retaining wall upward or downward.

V.S. Korovkin

2013-10-01

 
 
 
 
81

Quantification and reliability of center of pressure movement during balance tasks of varying difficulty.  

Science.gov (United States)

Postural control is often assessed by quantifying the magnitude of the center of pressure (COP) movement. However, these measures usually focus on the gross amount of movement and ignore the temporal structure of the COP signal. A novel non-linear analysis technique was recently developed to characterize the temporal structure of the COP signal with an output termed the entropic half-life [E(1/2)]. The E(1/2) reflects how much of the previous postural position is used to determine the current postural control strategy (memory effect). The purpose of this study was to quantify the E(1/2) and four COP movement magnitude measurements (medio-lateral and anterior-posterior excursion, path length, 95% ellipse area) for balance tasks increasing in sensory difficulty, as well as the test-retest reliability of each measure. Twenty-seven healthy young adults completed single limb stance tasks varying in sensory difficulty (rigid surface eyes open, rigid surface eyes closed, foam surface eyes open) on two separate occasions. Relative reliability was assessed using an intraclass correlation coefficient (ICC3,3). Absolute reliability was assessed using the standard error of the measurement (SEM) and the sensitivity of the measurement to true changes was assessed using the minimal detectable change (MDC95). The E(1/2) was found to have excellent reliability for all tasks tested (ICC range 0.82-0.91, SEM range 3.5-14.1mm, MCD95 range 9.7-39.2mm). The high reliability of the E(1/2) was comparable to that of movement magnitude measurements. This may be used in order to better understand the underlying motor control system. PMID:24855981

Baltich, Jennifer; von Tscharner, Vinzenz; Zandiyeh, Payam; Nigg, Benno M

2014-06-01

82

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

83

Effect of load cycle operation on reactivity balance and power density distribution in WWER-type pressurized water reactors  

International Nuclear Information System (INIS)

Starting from a quasistationary reactivity balance, the control reactivity needed for load cycle operation and the resulting power density distribution have been determined using a point model and a one-dimensional model. The models can be applied to different types of the daily scheduled load operation (sinusoidal, trapezoidal, and ramp-shaped) as well as to any other control concepts. The sinusoidal load cycle operation at constant main steam pressure has been determined to be the most preferable one. (author)

1983-01-01

84

The influence of barometric pressure fluctuations, earth tides and rainfall loading on fluid pressures in coastal plain aquifers, Burke County, Georgia  

Energy Technology Data Exchange (ETDEWEB)

High precision pressure measurements from several aquifers in the top 225 m of coastal plain sediments reveal that barometric pressure fluctuations, earth tides and rainfall loading create pressure fluctuations on the order of tens of centimeters. If not correctly identified, erroneous conclusions regarding the magnitude of pressure communication within and across aquifers during pumping tests may be inferred. Aquifer pressure data with an equivalent resolution of 0.1 mm change in water level were measured in 4 wells over a 10 day period at the USGS Miller's Pond Test Site. During this time, barometric pressures fluctuated by the equivalent of 20 cm of water. Aquifer pressures mimicked these changes, with corresponding barometric efficiencies ranging from 0.59 for the deepest well (215 to 224 m) to 0.73 for the shallowest (136 to 145 m). After removing barometric influences from the pressure data, periodic pressure fluctuations of 2 cm were observed. These correlate well with fluctuations in the earths gravitational field created by planetary motion. A twelve component earth tide model was used to calculate the magnitude of the gravitational fluctuations and provide a quantitative basis for comparing them to observed aquifer pressure fluctuations. Additionally, three rainfall events caused rapid and relatively large increases in aquifer pressures. Up to 4 cm increase in the aquifer pressure accompanied the heaviest rains. The pressures increased concurrent to the rains and decayed slowly to background levels over a several day period, indicating a loading response instead of an infiltration induced pressure increase. The relatively large magnitude of these influences, compared to the small changes induced by leakage across confining layers requires careful consideration in the data analysis.

Benson, S.M.; Moore, J.; Daggett, J.; Snipes, D.S. (Clemson Univ., SC (United States). Dept. of Earth Sciences)

1993-03-01

85

Earth  

Science.gov (United States)

This NASA (National Aeronautics and Space Administration) planet profile provides data and images of the planet Earth. These data include planet size, orbit facts, distance from the Sun, rotation and revolution times, temperature, atmospheric composition, density, surface materials and albedo. Images with descriptions show Earth features such as the Ross Ice Shelf in Antarctica, Simpson Desert in Australia, Mt. Etna in Sicily, the Cassiar Mountains in Canada, the Strait of Gibraltar, Mississippi River, Grand Canyon, Wadi Kufra Oasis in Libya, and Moon images such as Hadley Rille, Plum Crater, massifs and Moon rocks. These images were taken with the Galileo Spacecraft and by the Apollo missions.

86

Moessbauer spectroscopy of quenched high-pressure phases: investigating the Earth's interior  

International Nuclear Information System (INIS)

New phases formed at high pressure and temperature can be successfully quenched to ambient conditions if the kinetics of the back transformation are slow. One important application of this technique is to mineral physics - the combination of microscopic measurements of the structural, physical and chemical properties of high-pressure minerals measured in the laboratory with macroscopic geophysical and geochemical data to produce a unified description of the Earth's interior. The dominant high-pressure phases inferred to be present in the Earth's mantle have been synthesised using a multi-anvil press to correlate structural and chemical information obtained from Moessbauer data with bulk geophysical and geochemical data to determine properties of the mantle, such as the oxidation state. Results from experiments on the major transition zone minerals ?-(Mg,Fe)2SiO4, (Mg,Fe)SiO3 garnet and ?-(Mg,Fe)2SiO4 spinel include the discovery of significant Fe3+ in these phases synthesised in equilibrium with metallic iron and excess silica, implying that the oxygen fugacity (fO2) of the transition zone must be substantially lower than the upper mantle fO2. Moessbauer spectra of the lower mantle phase (Mg,Fe)SiO3 perovskite show that Fe2+ occupies the large distorted site almost exclusively, and that significant Fe3+ is present at the minimum fO2 stability limit. Low temperature spectra indicate a phase transition possibly corresponding to a distortion of the perovskite structure. Moessbauer spectra of FexO quenched from high pressure indicate that the Fe3+ content of samples in equilibrium with metallic iron is small, implying that the minimum amount of Fe3+ in the lower mantle (Mg,Fe)O at lower mantle conditions is also small. Moessbauer spectra from samples of (Mg,Fe)O synthesised at different temperatures and fO2 conditions show that the Fe3+ content can be reliably measured, and that it varies significantly with fO2. Implications of these results to properties of the Earth's interior are discussed. (orig.)

1994-11-01

87

Effects of high pressure on magnetic transitions in heavy rare earth metals  

Science.gov (United States)

Rare earth metals bear close resemblance to the 5f actinide metals that are critical to nuclear stockpile stewardship research. To better understand these materials, we have studied erbium, holmium, and terbium under high pressure and low temperatures in order to elucidate the magnetic transitions as these materials are compressed to different crystallographic phases. In erbium, we have undertaken four-probe electrical resistance measurements in a diamond anvil cell to temperatures as low as 10 K and pressures up to 20.3 GPa. We have also conducted x-ray diffraction measurements on erbium to 10 K and 20.4 GPa. In the electrical resistance measurements we saw a distinct change in the resistance slope at the antiferromagnetic Neel temperature, signaling a transition to its c-axis modulated antiferromagnetic phase. At pressures of 10.6 GPa and above the change in slope signaling antiferromagnetic order was suppressed. The x-ray diffraction measurements showed that this loss of transition occurred at the same pressure as the transition from the hexagonal close packed crystal structure (hcp) to the ?-Sm structure. In holmium, we made electrical resistance measurements to 10 K and 30.1 GPa which also showed a change in slope at the Neel temperature. The transition was suppressed at pressures above 9 GPa. Additionally, we collected neutron diffraction spectra of holmium at 89 K, 110 K, and 300 K at pressures as high as 6.6 GPa. These spectra confirmed the paramagnetic-to-antiferromagnetic transition at temperatures and pressures similar to those determined from the electrical resistance measurements. In terbium we made both electrical resistance and neutron diffraction measurements as well. The electrical resistance measurements showed a transition to the ferromagnetic phase at the Curie temperature at pressures up to 3.6 GPa, where the transition was suppressed. The neutron diffraction measurements showed that the ferromagnetic transition was indeed suppressed at this pressure and above and also confirmed that above 3.6 GPa the crystal structure undergoes a transition from hcp to ?-Sm. It is postulated that a change in the Fermi surface as the structure shifts from hcp to ?-Sm is responsible for the loss of ferromagnetism in terbium and antiferromagnetism in erbium and holmium.

Thomas, Sarah A.

88

Performance of pressure control valves and flow meters precision in operational irrigation-water balance accuracy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In pressure irrigation-water distribution networks, pressure regulating devices for controlling the discharged flow rate by irrigation units are needed due to the variability of flow rate. In addition, applied water volume is used controlled operating the valve during a calculated time interval, and assuming constant flow rate. In general, a pressure regulating valve PRV is the commonly used pressure regulating device in a hydrant, which, also, executes the open and close function. A hy...

Sa?nchez Calvo, Rau?l; Rodri?guez Sinobas, Leonor; Juana Sirgado, Luis; Laguna Pen?uelas, Francisco; Gil Rodri?guez, Mari?a; Benitez Buelga, Javier

2012-01-01

89

First-principles modelling of Earth and planetary materials at high pressures and temperatures  

International Nuclear Information System (INIS)

Atomic-scale materials modelling based on first-principles quantum mechanics is playing an important role in the science of the Earth and the other planets. We outline the basic theory of this kind of modelling and explain how it can be applied in a variety of different ways to probe the thermodynamics, structure and transport properties of both solids and liquids under extreme conditions. After a summary of the density functional formulation of quantum mechanics and its practical implementation through pseudopotentials, we outline the simplest way of applying first-principles modelling, namely static zero-temperature calculations. We show how calculations of this kind can be compared with static compression experiments to demonstrate the accuracy of first-principles modelling at pressures reached in planetary interiors. Noting that virtually all problems concerning planetary interiors require an understanding of materials at high temperatures as well as high pressures, we then describe how first-principles lattice dynamics gives a powerful way of investigating solids at temperatures not too close to the melting line. We show how such calculations have contributed to important progress, including the recent discovery of the post-perovskite phase of MgSiO3 in the D'' layer at the base of the Earth's mantle. A range of applications of first-principles molecular dynamics are then reviewed, including the properties of metallic hydrogen in Jupiter and Saturn, of water, ammonia and methane in Uranus and Neptune, and of oxides and silicates and solid and liquid iron and its alloys in the Earth's deep interior. Recognizing the importance of phase equilibria throughout the planetary sciences, we review recently developed techniques for the first-principles calculation of solid and liquid free energies, melting curves and chemical potentials of alloys. We show how such calculations have contributed to an improved understanding of the temperature distribution and the chemical composition throughout the Earth's interior. The review concludes with a summary of the present state of the field and with some ideas for future developments

2006-08-01

90

Thermodynamics of the Earth's core materials based on high-pressure experimental data  

Science.gov (United States)

Thermodynamics of iron and iron alloys are of crucial information for understanding of the composition, structure, and evolution of the Earth's core. Recent accumulated data from static high-pressure and -temperature experiments allows us to model the thermodynamic properties of both solid and liquid phases. In the present study, I examined the thermodynamics of the melting relations in the system Fe-FeO to the outer core-inner core boundary pressure from the latest static high-pressure and -temperature experiments. The modeling is divisible into (i) for end-member phases of Fe and FeO and (ii) for a liquid with an intermediate composition. (i) For the pure Fe system, I have included a recent laser-heated diamond anvil cell data on melting up to 200 GPa (ref.1) and pressure-volume-temperature data for face-centered cubic phase examined in a multi-anvil apparatus (ref. 2). (ii) At low pressures, non-ideality has been recognized for liquids in the system Fe-FeO. In the present study however, with the ideal solution model assumed for liquids under the core pressures, the calculated eutectic temperatures are not inconsistent with the results of the laser-heated DAC experiments showing a solid assemblage Fe+FeO was stable up to 4200 K (ref. 3). This indicates that the non-ideality decreases with increasing pressure and temperature and may diminish under the core conditions. The new solution model, namely ideal solution, predicts that the eutectic composition is about Fe-9.5 wt.%O, almost constant under the core pressures, which compositions would put the limit of the oxygen content in the core because the density of solid FeO is too small to match the inner core density. Thermodynamics allows us to derive the properties that are difficult to directly constrain by experiment. From the Gibbs free energy for the Fe-FeO liquids, I calculated the density, sound velocity, and adiabatic temperature gradient of a hypothetical oxygen-bearing outer core. I will show the effects of oxygen on the sound velocity and density of liquid iron under the outer core conditions. Also, I will discuss the distribution of oxygen in the outer core. Ref. 1. Anzellini et al. (2013 Science); 2. Tsujino et al (2013 EPSL); 3. Ozawa et al. (2011 Science)

Komabayashi, T.

2013-12-01

91

Pickup protons and pressure-balanced structures: Voyager 2 observations in merged interaction regions near 35 AU  

Science.gov (United States)

Five pressure-balanced structures, each with a scale of the order of a few hundredths of an astonomical unit (AU), were identified in two merged interaction regions (MIRs) near 35 AU in the Voyager 2 plasma and magnetic field data. They include a tangential discountinuity, simple and complex magnetic holes, slow correlated variations among the plasma and magnetic field parameters, and complex uncorrelated variations among the parameters. The changes in the magnetic pressure in these events are balanced by changes in the pressure of interstellar pickup protons. Thus the pickup protons probably play a major role in the dynamics of the MIRs. The solar wind proton and electron pressures are relatively unimportant in the MIRs at 35 AU and beyond. The region near 35 AU is transition region: the Sun is the source of the magnetic field, but the interstellar medium in source of pickups protons. Relative to the solar wind proton guyroadius, the thicknesses of the discontinuities and simple magnetic holes observed near 35 AU are at least an order of magnitude greater than those observed at 1 AU. However, the thicknesses of the tangential discontinuity and simple magnetic holes observed near 35 AU (in units of the pickup proton Larmor radius) are comparable to those observed at 1 AU (in units of the solar wind proton gyroradius). Thus the gyroradius of interstellar pickup protons controls the thickness of current sheets near 35 AU. We determine the interstellar pickup proton pressure in the PBSs. Using a model for the pickup proton temperature, we estimate that the average interstellar pickup proton pressure, temperature, and density in the MIRs at 35 AU are (0.53 +/- 0.14) x 10(exp -12) erg/cu cm, (5.8 +/- 0.4) x 10(exp 6) K and (7 +/- 2) x 10(exp -4)/cu cm.

Burlaga, L. F.; Ness, N. F.; Belcher, J. W.; Szabo, A.; Isenberg, P. A.; Lee, M. A.

1994-01-01

92

Direct solar and earth-albedo radiation pressure effects on the orbit of Pageos 1  

Science.gov (United States)

The orbit of the Pageos 1 balloon satellite was analyzed for the effects of direct solar and albedo radiation pressure. Anomalous behavior occurred in the orbital acceleration near the end of the 2nd year of the satellite's lifetime which may have resulted from the change in its shape; the shape has become slightly oblate, spinning about a minor axis and precessing about the direction of the sun. The near-earth micrometeoroid particle flux was estimated to be 5 x 10 to the -8th/sq cm/s by analyzing the balloon inflation process with sublimating compounds and the resulting variation of the satellite mass due to the leakage through the holes produced by micrometeoroid bombardment.

Zerbini, S.

1980-01-01

93

South Dakota Space Grant Consortium: Balancing Indigenous Earth System and Space Science with Western/Contemporary Science  

Science.gov (United States)

The South Dakota Space Grant Consortium (SDSGC) was established March 1, 1991 by a NASA Capability Enhancement Grant. Since that time SDSGC has worked to provide earth system and space science education, outreach and services to all students across South Dakota. South Dakota has nine tribes and five Tribal Colleges. This has presented a tremendous opportunity to develop sustainable equitable partnerships and collaborations. SDSGC believes strongly in developing programs and activities that highlight and reinforce the balance of Indigenous science and ways of knowing with current findings in Western/Contemporary Science. This blending of science and culture creates a learning community where individuals especially students, can gain confidence and pride in their unique skills and abilities. Universities are also witnessing the accomplishments and achievements of students who are able to experience a tribal environment and then carry that experience to a college/university/workplace and significantly increase the learning achievement of all. The presentation will highlight current Tribal College and Tribal Community partnerships with the Rosebud Sioux Reservation (Sinte Gleska University), Pine Ridge Indian Reservation (Oglala Lakota College), Standing Rock Sioux Reservation (Sitting Bull College) and Cheyenne River Sioux Reservation (Si Tanka) amongst others. Programs and activities to be explained during the presentation include but not limited to: NASA Workforce Native Connections, Scientific Knowledge for Indian Learning and Leadership (SKILL), NSF "Bridges to Success" Summer Research Program, NSF "Fire Ecology" Summer Research Experience, as well as geospatial and space science programs for students and general community members. The presentation will also cover the current initiatives underway through NASA Workforce Development. These include: partnering with the Annual He Sapa Wacipi (Black Hills Pow Wow - attendance of 14,000 Natives) to host Native Space Days 2005 (October 2005), NASA research and internship programs, and the NASA Student Fellowship Summit. An overview of recent American Indian student success will conclude the presentation. The South Dakota School of Mines and Technology has struggled over many years to develop and implement sustainable successful initiatives with Tribal Colleges and Communities. The motivating philosophy is the betterment of all people in South Dakota and the nation through developing a worldview and understanding of the integrated nature of all things, especially earth system and space science. If people are provided equity and access, there is no limit to what they can accomplish. SDSM&T in the last three years has graduated nineteen Natives with degrees in engineering, many of those students Tribal College transfers. This is a significant increase, as only forty Natives had graduated from SDSM&T between the years of 1970 and 2000. SDSM&T has seen a number of "historical firsts" in the past five years. We see this as being a direct result of creating for students an educational philosophy and process where Indigenous understanding and connections become the foundation on which to build a STEM degree program. NASA's presence on the SDSM&T campus and in South Dakota has provided the necessary focus and encouragement for success to take place. We are building bridges in South Dakota and the builders are from Indian Country.

Bolman, J.; Nall, J.

2005-05-01

94

Generation of methane in the Earth's mantle: in situ high pressure-temperature measurements of carbonate reduction.  

Science.gov (United States)

We present in situ observations of hydrocarbon formation via carbonate reduction at upper mantle pressures and temperatures. Methane was formed from FeO, CaCO(3)-calcite, and water at pressures between 5 and 11 GPa and temperatures ranging from 500 degrees C to 1,500 degrees C. The results are shown to be consistent with multiphase thermodynamic calculations based on the statistical mechanics of soft particle mixtures. The study demonstrates the existence of abiogenic pathways for the formation of hydrocarbons in the Earth's interior and suggests that the hydrocarbon budget of the bulk Earth may be larger than conventionally assumed. PMID:15381767

Scott, Henry P; Hemley, Russell J; Mao, Ho-Kwang; Herschbach, Dudley R; Fried, Laurence E; Howard, W Michael; Bastea, Sorin

2004-09-28

95

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

Science.gov (United States)

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 & 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 & measurement conditions (for gauge and absolute pressure measurements), uncertainty budget preparation and evaluation of measurement uncertainty are discussed in detail in this paper.

Vijayakumar, D. Arun; Prakash, Om; Sharma, R. K.

2012-11-01

96

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

International Nuclear Information System (INIS)

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

97

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

98

Pressure dependence of the magnetic properties of some rare earth intermetallic systems  

International Nuclear Information System (INIS)

The magnetization and susceptibility of several rare earth intermetallic compounds have been measured under hydrostatic pressure, P, up to 10 kbar and in magnetic fields, H, up to 60 kG. For all the materials studied the magnetic properties are strongly influenced by crystalline electric field (CEF) effects. For the Pr-monochalcogenides and TmAl3 the low temperature van Vleck-like susceptibility, chi, decreases with increasing P. This is consistent with an increase of the CEF interaction as the lattice constant is reduced. This trend is also observed for the CEF level structure of dilute Tb in superconducting LaAl2 (where the impurity pairbreaking is reduced with increasing P). However, for the Pr- and Tm- monopnictides chi increases with increasing P. The pressure dependence of the magnetic ordering temperatures for singlet ground state TbSb, Pr3Tl and TmS is also reported. The effect of P is very strong on the low temperature magnetic anomalies of TmSe; the transition fields increase with increasing P at a rate of +1.7 kG/kbar, and these results are discussed in terms of the mixed-valence nature of TmSe

1976-09-01

99

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

100

Impurity trapped exciton states related to rare earth ions in crystals under high hydrostatic pressure  

Energy Technology Data Exchange (ETDEWEB)

Emission related to rare earth ions in solids takes place usually due to 4f{sup n} {yields} 4f{sup n} and 4f{sup n-1}5d{sup 1} {yields} 4f{sup n} internal transitions. In the case of band to band excitation the effective energy transfer from the host to optically active impurity is required. Among other processes one of the possibilities is capturing of the electron at excited state and hole at the ground state of impurity. Localization of electron or hole at the dopand site creates a long range Coulomb potential that attracts the second carrier which then occupies the localized Rydberg-like states. Such a system can be considered as impurity trapped exciton. Usually impurity trapped exciton is a short living phenomenon which decays non-radiatively leaving the impurity ion in the excited state. However, in several compounds doped with Eu{sup 2+} the impurity trapped exciton states become stable and contribute to the radiative processes though anomalous luminescence that appears apart of the 4f{sup 7} {yields} 4f{sup 7} and 4f{sup 7}5d{sup 1} {yields} 5f{sup 7} emission. In this contribution pressure effect on energies of the 4f{sup n-1}5d{sup 1}{yields}5f{sup n} transitions in Ln doped oxides and fluorides as well as influence of pressure on the energy of impurity trapped exciton states is discussed. The latest results on high pressure investigations of luminescence related to Pr{sup 3+}, and Eu{sup 2+} in different lattices are reviewed.

Grinberg, M., E-mail: fizmgr@univ.gda.pl; Mahlik, S. [University of Gdan' sk, Institute of Experimental Physics (Poland)

2013-01-15

 
 
 
 
101

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 the mean power needed to maintain an electron-ion pair in the discharge 0 have been determined as functions of the pressure. It is experimentally proven that 0 is independent of the electron densi...

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

1987-01-01

102

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

2013-08-01

103

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

Energy Technology Data Exchange (ETDEWEB)

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{sup -1} Hz{sup -1/2} is preserved down to frequencies of several Hz even after strong motion in the Earth's magnetic field.

Schultze, Volkmar; IJsselsteijn, Rob; May, Torsten; Meyer, Hans-Georg [Department of Quantum Electronics, Institute for Physical High Technology, D-07745 Jena (Germany)

2003-07-01

104

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 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 wi...

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

2011-01-01

105

Simplification of hydraulic balance without differential pressure regulators; Vereinfachung des hydraulischen Abgleichs. Wegfall der Differenzdruckregler  

Energy Technology Data Exchange (ETDEWEB)

In many heating systems, it would be possible to reduce the number of armatures to save energy. The author presents an example to show the shortcomings of systems with differential pressure controllers and recirculation pumps and points out the advantages of jet pump control. (orig.)

Gebauer, Marc [W. Baelz und Sohn GmbH und Co., Heilbronn (Germany)

2010-12-15

106

Variation in the electrical properties of single crystals of rare earth hexaborides with temperature and pressure  

Energy Technology Data Exchange (ETDEWEB)

Single crystals of the rare earth (RE) hexaborides EuB/sub 6/, YbB/sub 6/ and SmB/sub 6/ were prepared by the solution method with various atomic RE:B ratios in the starting material. The electrical resistivity and Hall coefficient were measured between 4.2 and 300 K on single crystals of SmB/sub 6/ with different lattice parameters. For all crystals the resistivity at 4.2 K is nearly 10/sup 4/ times greater than its 300 K value of (1-4)x10/sup -4/..cap omega.. cm. The Hall coefficient is positive between 300 and 60 K and becomes negative below about 60 K. The resistivities of single crystals of EuB/sub 6/, YbB/sub 6/ and SmB/sub 6/ under hydrostatic pressures of up to 14 kbar were found to decrease by nearly 40%, 14% and 10% respectively. The data obtained are compared with the previously published results. The stoichiometry and impurities in these crystals are discussed.

Korsukova, M.M.; Stepanov, N.N.; Gontcharova, E.V.; Gurin, V.N.; Nikanorov, S.P.; Smirnov, I.A. (AN SSSR, Leningrad. Fiziko-Tekhnicheskij Inst.)

1981-11-15

107

Pressure-induced valence change in the rare earth metals: The case of praseodymium  

Energy Technology Data Exchange (ETDEWEB)

The rare earth metal praseodymium (Pr) transforms from the d-fcc crystal structure (Pr-III) to {alpha}-U one (Pr-IV) at 20-bar GPa with a large volume collapse ({delta}V/V=0.16), which is associated with the valence change of the Pr ion. The two 4f electrons in the Pr ion is supposed to be itinerant in the Pr-IV phase. In order to investigate the electronic state of the phase IV, we performed the high-pressure electrical resistance measurement using the diamond anvil cell up to 32-bar GPa. In the Pr-IV phase, the temperature dependence of the resistance shows an upward negative curvature, which is similar to the itinerant 5f electron system in actinide metals and compounds. This suggests the narrow quasiparticle band of the 4f electrons near the Fermi energy. A new phase boundary is found at T{sub 0} in the Pr-IV phase. From the temperature and magnetic field dependences of the resistance at 26-bar GPa, the ground state of the Pr-IV phase is suggested to be magnetic. Several possibilities for the origin of T{sub 0} are discussed.

Tateiwa, N. [Advanced Science Research Center, Japan Atomic Energy Research Institute, Tokai, Ibaraki 319-1195 (Japan) and Department of Applied Quantum Physics, Faculty of Engineering, Kyushu University, Hakozaki, Fukuoka 812-8581 (Japan)]. E-mail: tateiwa@popsvr.tokai.jaeri.go.jp; Nakagawa, A. [Department of Applied Quantum Physics, Faculty of Engineering, Kyushu University, Hakozaki, Fukuoka 812-8581 (Japan); Fujio, K. [Department of Applied Quantum Physics, Faculty of Engineering, Kyushu University, Hakozaki, Fukuoka 812-8581 (Japan); Kawae, T. [Department of Applied Quantum Physics, Faculty of Engineering, Kyushu University, Hakozaki, Fukuoka 812-8581 (Japan); Takeda, K. [Department of Applied Quantum Physics, Faculty of Engineering, Kyushu University, Hakozaki, Fukuoka 812-8581 (Japan); Institute of Environmental Systems, Faculty of Engineering, Kyushu University, Hakozaki, Fukuoka 812-8581 (Japan)

2006-02-09

108

Turbulent kinetic energy balance measurements in the wake of a low-pressure turbine blade  

International Nuclear Information System (INIS)

The turbulent kinetic energy budget in the wake generated by a high lift, low-pressure two-dimensional blade cascade of the T106 profile was investigated experimentally using hot-wire anemometry. The purpose of this study is to examine the transport mechanism of the turbulent kinetic energy and provide validation data for turbulence modeling. Point measurements were conducted on a high spatial resolution, two-dimensional grid that allowed precise derivative calculations. Positioning of the probe was achieved using a high accuracy traversing mechanism. The turbulent kinetic energy (TKE) convection, production, viscous diffusion and turbulent diffusion were all obtained directly from experimental measurements. Dissipation and pressure diffusion were calculated indirectly using techniques presented and validated by previous investigators. Results for all terms of the turbulent kinetic energy budget are presented and discussed in detail in the present work.

2011-02-01

109

Fluid balance and colloid osmotic pressure in acute respiratory failure: emerging clinical evidence  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Available evidence suggests that both hydrostatic and osmotic forces are important in the development of acute respiratory distress syndrome (ARDS) or, more broadly, acute lung injury (ALI). More than 80% of ARDS patients in a large-scale randomized controlled trial (RCT) exhibited, at least intermittently, pulmonary artery wedge pressures (PAWP) above 18 mmHg. Retrospective analyses have shown that PAWP elevation is associated with increased mortality. Reduction in serum total protein (STP) ...

Martin, Greg S.

2000-01-01

110

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

111

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

CERN Document Server

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, Nicolas; Pinsault, Nicolas; Moreau-Gaudry, Alexandre; Fleury, Anthony; Demongeot, Jacques; Payan, Yohan

2007-01-01

112

The temperature structure and pressure balance of magnetic loops in active regions  

International Nuclear Information System (INIS)

EUV observations show many active region loops in lines formed at temperatures between 104K and 2X106K. The brightest loops are associated with flux tubes leading to the umbrae of sunspots. It is shown that the high visibility of certain loops in transition region lines is due principally to a sharp radial decrease of temperature to chromospheric values toward the loop axis. The plasma density of these cool loops is not significantly greater than in the hot gas immediately surrounding it. Consequently, the internal gas pressure of the cool material is clearly lower. The hot material immediately surrounding the cool loops is generally denser than the external corona by a factor 3-4. When the active region is examined in coronal lines, this hot high pressure plasma shows up as loops that are generally parallel to the cool loops but significantly displaced laterally. In general the loop phenomenon in an active region is the result of temperature variations by two orders of magnitude and density variations of around a factor five between adjacent flux tubes in the corona. (Auth.)

1975-01-01

113

Small Scale Pressure-Balanced Structures Driven by Slow-mode Waves in the Solar Wind  

Science.gov (United States)

This work aims to reveal the dependence of the properties of small-scale PBSs on the background magnetic field (B0) 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 fast solar wind at 1 AU. By wavelet cross-coherence analysis, we obtain the correlation coefficients and phase angle between the thermal pressure Pth and the magnetic pressure PB, distributing against the temporal scale and the angle ?xB between B0 and 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 ?xB. Suspecting that the isolated small PBSs are formed by compressive waves in situ, we continue this study by testing the wave mode forming a small-scale PBS with B0 quasi-parallel to GSE-x. We use the proton velocity distribution functions to reveal the proton temperature anisotropy T? /T?. Besides, minimum variance analysis is applied to find the magnetic field minimum variance vector BN as wave vector k. We also study the time variation of the cross-helicity sigma_c and compressibility Cp, and compare with that from the numerical predictions for slow-mode waves. Finally, short time small-scale PBS is proved to be driven by oblique slow-mode waves in the solar wind.

Yao, S.; Tu, C.; He, J.; Wang, L.; Marsch, E.

2013-12-01

114

In-situ response time testing of force-balance pressure transmitters in nuclear power plants  

International Nuclear Information System (INIS)

This paper reports on recommendations for response time testing of safety system pressure transmitters in nuclear power plants that are found in Regulatory Guide 1.118 and requirements are defined in plant technical specifications. The conventional testing method involves simultaneously applying a pressure ramp signal to the process transmitter and to a fast-response reference transmitter. The time delay between the response of the two transmitters, when they obtain a predetermined value, is called the process transmitter response time. This method is referred to as the ramp test. Although the ramp test is an accepted method, large variations in its results are sometimes encountered because of empirical difficulties associated with the test. This test requires access to each transmitter, and it must be performed inside the containment during shutdown. The in-situ test is accomplished by interrupting the power to the transmitter for a few seconds. It is referred to as the Power Interrupt (PI) test, and it can be conducted while the plant is operating. The test includes the entire electromechanical system and the response time is obtained by analyzing the transient response following the restoration of power to the transmitter. Response times obtained from the PI test and the ramp test are in good agreement and usually differ by less than 50 ms

1989-05-15

115

The “Stick-Slip” Phenomenon During the Active Earth Pressure Failure of a Granular Soil of Analogical Material  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of this paper is to highlight the "stick-slip" phenomenon in the mechanisms of failure related to active earth pressure of an analogical material simulating a granular medium. For this, a two-dimensional small-scale model was used and a phenomenological analysis of these mechanisms was conducted employing measurements of the fields of deformations using the method of digital image correlation. It was noted that a fluctuation in the response of the material occurs during the equal increments of displacements imposed on the mobile wall. This incremental response of the medium during the failure process related to active earth pressure explains the "stick-slip" phenomenon

S. M. Daoud

2014-02-01

116

Engineering kinematic theory of the contact earth pressure and its application to the static calculation of thin quay walls  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Construction of deep-water thrust berthing structures requires using new and more perfect methods of calculation containing fewer assumptions. A version of the engineering kinematic theory of contact earth pressure in the application to the water-transport and offshore structures was suggested in the article. A dimensionless static “compression – tension” diagram of the soil, presented by curvilinear function, was used in the method. In this case, the displacement of the limit point of ...

2013-01-01

117

Pressure and Ionization Balances in the Circum-Heliospheric Interstellar Medium and the Local Bubble  

CERN Multimedia

A disconcerting mismatch of thermal pressures for two media in contact with each other, (1) the warm, Circum-heliospheric Interstellar Medium (CHISM) and (2) the very hot material within a much larger region called the Local Bubble (LB), has troubled astronomers for over two decades. A possible resolution of this problem, at least in part, now seems possible. We now understand that earlier estimates for the average electron density in the very hot LB plasma were inflated by an unrecognized foreground contamination to the low energy diffuse X-ray background measurements. This foreground illumination arises from photons emitted by charge exchange reactions between solar wind ions and neutral atoms from the interstellar medium that enter into the heliosphere. However, with the resolution of this problem comes a new one. The high ionization fraction of helium in the CHISM, relative to that of hydrogen, could be understood in terms of the effects from a strong flux of EUV and X-ray radiation coming from both the L...

Jenkins, Edward B

2008-01-01

118

The effect of different skin-ankle brace application pressures on quiet single-limb balance and electromyographic activation onset of lower limb muscles  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract 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 on quiet single limb balance and the electromyographic (EMG activation sequence of four lower limb muscles. Methods Thirty three male physical education students who volunteered to take part in the study were measured under three ankle brace conditions: i without brace, ii with brace and 30 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. Results The results showed that overall balance (total stability parameter was not significantly affected in any of the three ankle brace conditions. However, the anteroposterior centre of pressure excursion and centre of pressure excursion velocity were significantly increased with the application of ankle brace, both with 30 and 60 kPa application pressures. Furthermore, it was found that single limb balance was significantly worse with closed eyes compared to open eyes. EMG measurements showed that the sequence of lower limb activation onset was not affected in any of the three ankle brace application conditions. The results of this study showed that the application of an ankle brace with two different skin-brace interface pressures had no effect on overall single limb balance and the sequence of lower limb muscle activation. Conclusion These findings suggest that peripheral joint receptors are either not adequately stimulated by the brace application and therefore are not able to alter the balance control strategy of the CNS, or that they play a less important role in the control of single limb balance. Further research is needed in this area with more dynamic and functional measurements, before the safe use of ankle bracing can be widely recommended.

Papadakis Stamatios A

2007-09-01

119

Anomalous Pressure Dependence of Dipolar Relaxation Times in Rare Earth Doped Lead Fluoride.  

Science.gov (United States)

Electrical relaxation measurements at high pressures have been carried out on lead fluoride doped with lanthanum and cerium. A single, strong relaxation peak is observed and the relaxation time decreases with pressure. This is contrary to the behavior exh...

J. J. Fontanella M. C. Wintersgill D. R. Figueroa A. V. Chadwick C. G. Andeen

1984-01-01

120

The Effect of Nickel on the Seismic Wave Belocities of Iron at the Pressure Conditions of the Earth's Core  

Science.gov (United States)

Understanding the physical properties of the Earth's core is a key step in the study of the evolution and dynamics of our planet. For much of the last century, based on studies of meteorites [1], it was believed that Earth's core was predominantly a mixture of iron and nickel. More specifically, the Earth's inner core is a solid Fe-Ni alloy at high temperature (T, 6000 K) and high pressure (P, 360 GPa). Furthermore, to account for the lower than expected density in the Earth's core, it has been suggested that light elements must also be present [2]. While the effect of light elements on the properties of iron have been the subject of an extensive literature [3-6], the effect of nickel on the properties of iron has often been overlooked; this is due to the expectation, based on their proximity in the periodic table, that the properties of Ni are sufficiently similar to those of iron that the presence of nickel can be neglected. Although recent research using high P-T experiments and theoretical studies of Fe-Ni alloys has been performed in order to establish whether nickel affects the physical properties of iron, the results have been inconclusive and sometimes contradictory [7-11]. Here we present a DFT study of the athermal elastic properties of solid Fe-Ni alloys at core pressures using the GGA. We have calculated the equation of state (EoS) for Fe-Ni alloys at several compositions for bcc, fcc and hcp structures, and fitted the results to Birch-Murnaghan 3rd order equations of state. We have also calculated the elastic constants for each structure at 360 GPa and evaluated the seismic wave velocities. Our results show that the effect of small amounts of Ni is significant (-1.9% in vp and -4.0% in vs for hcp structure of Fe93.25-Ni6.75 alloy), and therefore nickel must be taken into account if a detailed model of the Earth's inner core is to be constructed. Other aspects of the influence of nickel, such as its effect on the high P-T phase diagram and melting curve, have yet to be conclusively established. 1. McDonough, Sun, Chem Geol 120 (1995) 223 2. Poirier, Phys Earth Planet Int 85 (1994) 319 3. Côté, Vo?adlo, Dobson, Alfè, Brodholt, Phys Earth Planet Int 178 (2010) 2 4. Shahar, Xiegler, Young, Ricolleau, Schauble, Fei, Earth Planet Scie Lett 288 (2009) 228 5. Lin, Scott, Fischer, Chang, Kantor, Prakapenka, Geophys Res Lett 36 (2009) 6306 6. Côté, Vo?adlo, Brodholt, Geophys Res Lett 35 (2008) 5306 7. Kuwayama, Hirose, Stat, Ohishi, Earth Planet Scie Let 273 (2008) 379 8. Shabashov, Zamatovskii, Pilyugin, Phys. Met Metallogr+ 108 (2009) 475 9. Erkholm, Mikhaylushkin, Simak, Johansson, Abrikosov, Earth Planet Sci Lett 308 (2011) 90 10. Kantor, Kantor, Kurnosov, Kuznetsov, Dubrovinskaia, et al., Phys Earth Planet Int 164 (2007) 83 11. Asker, Vitos, Abrikosov, Phys. Rev B 79 (2009) 214112

Martorell Masip, B.; Vocadlo, L.; Brodholt, J. P.; Wood, I.

2011-12-01

 
 
 
 
121

High pressure transport measurements on the rare earth systems samarium hexaboride, cerium bismuth platinide and europium hexaboride  

Science.gov (United States)

High pressure transport and magnetotransport measurements on the rare earth systems SmB6,/ Ce3Bi4Pt3 and EuB6 as well as high pressure magnetic measurements on EuB6 are reported. In the case of SmB6 the resistivity, magnetoresistance and Hall effect were measured at pressures to 150 kbar, and fields as high as 18 T, over temperatures from 1 K to 300 K. At 1 bar SmB6 is a metal with a resistivity well in excess of the unitarity limit at low temperature. The mean field hybridization model used for Kondo Insulators cannot explain the sudden collapse of the gap in this material at a sample dependent critical pressure or the gap's weak quadratic field dependence. At high pressure the resistivity of SmB6 resembles that of a non ordering heavy fermion material with a T2 temperature dependence. The field dependence of the high pressure resistivity suggests a Fermi surface orbit shaped similarly to one in LaB6. The resistivity of the Kondo Insulator Ce3Bi4Pt3 was measured at pressures up to 150 kbar at temperatures between 1 K and 300 K. The gap ? increases by an order of magnitude in this pressure range. From ?, the pressure dependences of the Kondo temperature and Ce valence were determined and found consistent with the predictions of the mean field hybridization model in the weak coupling limit. Three dimensional variable range hopping was found to dominate the low temperature transport at pressures above 30 kbar. In EuB6 the resistivity and magnetoresistance were measured at pressures from 1 bar to 169 kbar in fields to 7 T over temperatures from 1 K to 300 K. The magnetoresistance near the ordering temperature TC is negative and scales with the magnetization while at low temperature it is large, ?rho/?0 > 10, and positive. Shubnikov-de Haas oscillations about a small branch of the Fermi surface were observed. In addition TC was measured using a magnetic susceptibility technique at pressures from 1 bar to 57 kbar. The apparatus is described. Tc increases with pressures up to ~100 kbar, then becomes nearly pressure independent. Finally evidence of an unusual two step magnetic ordering process was found in the temperature dependence of the spontaneous magnetization and resistivity.

Cooley, Jason Christopher

1997-11-01

122

Role of stratospheric ozone in the zonal and seasonal radiative energy balance of the Earth-troposphere system  

International Nuclear Information System (INIS)

The role of ozone in the tropospheric-surface energy balance is discussed in the context of its latitudinally and seasonally varying modulation of solar and longwave energy fluxes. We analyze in detail the various radiative energy inputs to the stratosphere and the radiative fluxes from the stratosphere to the troposphere. We confirm the result of past analyses that, for a uniform change in ozone, the global average perturbation in radiative fluxes to the troposphere and surface is small since the perturbations in solar and infrared fluxes nearly cancel. However, this result probably severely underestimates the contribution of changes in the distribution of ozone to global climate. It is difficult to evaluate the changes in tropospheric radiation needed to determine a change of climate due to a change of O3. Not even the net global average perturbation radiative fluxes to the troposphere can be calculated without knowing the change of the vertical ozone profile, and the vertical and latitudinal variations of the troposphere-surface perturbation heating rates are likely to be more important for climate change than the net global values

1979-01-01

123

Pressure-induced structural phase transition and elastic properties in rare earth CeBi and LaBi  

International Nuclear Information System (INIS)

Pressure is one of the external parameters by which the interplay of the f-electrons with the normal conduction electrons may be varied. At ambient conditions the rare-earth compounds are characterized by a fixed fn configuration of atomic-like f-electrons, but the decreased lattice spacing resulting from the application of pressure eventually leads to the destabilization of the f-shell. The theoretical description of this electronic transition remains a challenge. The present study reports a comprehensive study on structural, electronic band structures, elastic and lattice dynamical properties of rare earth monopnictides CeBi and LaBi using first principles density functional calculations within the pseudopotential approximation. Both compounds possess NaCI (B1) structure at ambient pressure and transform either to CsCI or body centered tetragonal (BCT) structure. Our results concerning equilibrium lattice parameter and bulk modulus agree well with the available experimental and previous theoretical data. The volume change at the crystallographic transition is attributed to a decrease of the cerium valence or a lowering of the p-f hybridization due to the larger interatomic distances in both high pressure phases. The equation of state for rare earth bismuth compounds are calculated and compared with available experimental results. From the total energy and relative volume one can clearly see the relative stabilities of the high pressure phases of both compounds. As the primitive tetragonal phase of both compounds. As the primitive tetragonal phase can be viewed as a CsCl structure, one may think of a transition from B1 to B2. We have also calculated band structure for both phase and here we have presented for B1 case. The narrow bands originating above the Fermi level are mainly due to Ce 'f'-like states, and the major contribution to the density of states is mainly from Ce 'd'-like states. Furthermore, in high-pressure CsCI phase, there is an appreciable hybridization between Ce 'd'-like and 'f'-states

2011-09-25

124

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

125

Structural and electronic transitions in rare-earth metal hydrides at high pressures  

International Nuclear Information System (INIS)

Compression of rare-earth metal, Y, with hydrogen fluid produced insulating trihysdide YH3, which showed a structural transition from hexagonal to fcc metal lattice at about 10 GPa and successively an electronic transition with band gap closure at 23 GPa on further compression. (author)

2006-11-01

126

Quantifying Uncertainty in the Predictions of the SimSphere Land Biosphere Model in Simulating Key Parameters Characterising Earth's Energy Balance  

Science.gov (United States)

Soil Vegetation Atmosphere Transfer (SVAT) models are becoming the preferred scientific tool to assess land surface energy fluxes due to their computational efficiency, accuracy and ability to provide results at fine temporal scales. An all-inclusive validation of those models is a fundamental step before those can be confidently used for any practical application or research purpose alike. SimSphere is an example of a SVAT model, simulating a large array of parameters characterising various land surface interactions over a 24 hour cycle at a 1-D vertical profile. Being able to appreciate the uncertainty of SimSphere predictions, is of vital importance towards increasing confidence in the models' overall use and ability to represent accurate land surface interactions. This is particularly important, given that its use either as a stand-alone tool or synergistically with Earth Observation (EO) data is currently expanding worldwide. In the present study, uncertainty in the SimSphere's predictions is evaluated at seven European sites, representative of a range of ecosystem conditions and biomes types for which in-situ data from the CarboEurope IP operational network acquired during 2011 were available. Selected sites are characterised by varying topographical characteristics, which further allow developing a comprehensive understanding on how topography can affect the models' ability to reproduce the variables which are evaluated. Model simulations are compared to in-situ data collected on cloud free days and on days with high Energy Balance Ratio. We focused here specifically on evaluating SimSphere capability in predicting selected variables of the energy balance, namely the Latent Heat (LE), Sensible heat (H) and Net Radiation (Rn) fluxes. An evaluation of the uncertainty in the model predictions was evaluated on the basis of extensive statistical analysis that was carried out by computing a series of relevant statistical measures. Results obtained confirmed the correspondence of the model structure to real conditions for which it had been parameterised, evidencing its ability to reproduce reasonably satisfactory the examined parameters, particularly so over flat terrain sites and specific land cover types. Given the very small number of SimSphere validation studies, our work contributes decisively towards obtaining a better understanding of the model structure and correspondence to a real world system. The latter, not only provides very important information to future model users but also is of potential key value to efforts ongoing at present by different Space Agencies examining the use of SimSphere synergistically with Earth Observation data in developing operational products at a global scale. KEYWORDS: SimSphere, Latent Heat flux, Sensible Heat fulx, Net Radiation, SVAT; Land Surface Interactions, CarboEurope.

North, Matthew; Petropoulos, George

2014-05-01

127

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

128

Direct qualitative and quantitative determination of rare earths after separation by high pressure liquid chromatography (HPLC)  

International Nuclear Information System (INIS)

The rare earths from lanthanum to erbium can be separated by means of HPLC in an eluent system containing di-isopropylether/tetrahydrofuran/nitric acid (100:30:3), and they are determined qualitatively and quantitatively after calibration. Fluorescence quenching of THF at break-through of the single elements serves as indication method. This quenching is proportional to the concentration. The calibration curve is linear within 0.2 to 0.02 moles input. Standards, ores (monazites, cerite earths, yttriae) and technical products were analysed qualitatively and quantitatively. The results obtained are in good agreement with analytical values from different methods. The relative standard deviation is 1.8-3% (N = 10). The procedure takes 50 min from dissolution of the analytical sample. (orig.)

1980-01-01

129

Pressure-induced novel superconductivity and heavy fermion state in rare earth compounds  

International Nuclear Information System (INIS)

We have carried out the electrical resistivity measurements under high pressures up to 24 GPa for CeTX3 (T: Co and Ir, X: Si and Ge), CePd5Al2 and YbIr2Zn20 in order to investigate quantum criticality and superconductivity. Antiferromagnets CeTX3 with the non-centrosymmetric tetragonal structure show superconductivity under high pressures and reveal a huge upper critical field for H? [001]. An antiferromagnet CePd5Al2, which is an isostructural family of a heavy fermion superconductor NpPd5Al2, also shows superconductivity under high pressures. In these compounds, superconductivity appears in the vicinity of quantum critical point. On the other hand, YbIr2Zn20 without magnetic ordering approaches to the quantum critical point with increasing pressure and exhibits a super-heavy fermion state exceeding 10 J/(K2· mol).

2012-12-17

130

High-pressure phase transitions in the rare-earth orthoferrite LaFeO3.  

Science.gov (United States)

Sequential Rietveld refinements were applied on high-pressure synchrotron powder X-ray diffraction measurements of lanthanum ferrite (LaFeO3) revealing two phase transitions on the room-temperature isotherm up to a pressure of 48?GPa. The first structural phase transition of second order occurs at a pressure of 21.1?GPa, changing the space group from Pbnm to Ibmm. The second transition, involving a isostructural first-order phase transition, occurs at approximately 38?GPa, indicating a high-spin to low-spin transition of the Fe(3+) ion. Following the behavior of the volume up to the hydrostatic limit of methanol-ethanol it was possible to use inverted equations of state (EoS) to determine a bulk modulus of B0 = 172?GPa and a corresponding pressure derivative of B'0 = 4.3. In addition, the linearized version of the inverted EoS were used to determine the corresponding moduli and pressure derivatives for each lattice direction. PMID:24892592

Etter, Martin; Müller, Melanie; Hanfland, Michael; Dinnebier, Robert E

2014-06-01

131

Phase transformations in americium at high pressure: Relation to rare earth elements  

International Nuclear Information System (INIS)

The crystal structure of 241Am has been investigated up to 18.0 GPa, using a diamond anvil high-pressure apparatus. The normal dhep form of Am, stable at 1 atm and room temperature, undergoes three-phase transformations below 18.0 GPa. The first transformation occurs at about 5.0 +- 1.0 GPa, the second occurs at about 10.0 +- 1.0 GPa, and the third occurs at about 15.0 +- 1.0 GPa. The structure of the Am phase at 5-GPa pressure is fcc. However, we are unable to determine the structure of the new phases at about 10.0- and 15.0-GPa pressure from our present data. The structural behavior of Am showing that Am undergoes a sequence of structural transformations somewhat similar to the lanthanide metals is discussed

1980-12-10

132

The high-pressure phase of alumina and implications for Earth's D? layer  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Using ab initio simulations and high-pressure experiments in a diamond anvil cell, we show that alumina (Al2O3) adopts the CaIrO3-type structure above 130 GPa. This finding substantially changes the picture of high-pressure behavior of alumina; in particular, we find that perovskite structure is never stable for Al2O3 at zero Kelvin. The CaIrO3-type phase suggests a reinterpretation of previous shock-wave experiments and has important implications for the use of alumina as a window material i...

Oganov, Artem R.; Ono, Shigeaki

2005-01-01

133

Plasma pressure distribution in the equatorial plane of the Earth's magnetosphere at geocentric distances of 6-10 R E according to the international THEMIS mission data  

Science.gov (United States)

The structure of the averaged plasma pressure distribution in the plasma ring around the Earth at geocentric distances of ˜6-10 R E has been determined. The distribution function moments measured on the international THEMIS mission satellites have been used. The plasma pressure distribution in the equatorial plane at 15 R E > XSM > -15 R E and 15 R E > YSM > -15 R E has been statistically studied. The radial dependence of the plasma pressure at the day-night and morning-evening meridians has been analyzed. It has been indicated that the plasma ring around the Earth has a structure, which is close to being azimuthally symmetric. The achieved results have been compared with the pressure distributions obtained previously. It has been indicated that in the overlapping regions, the achieved results agree with the previously obtained data within the pressure determination errors.

Kirpichev, I. P.; Antonova, E. E.

2011-08-01

134

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

135

3-D Force-balanced Magnetospheric Configurations  

International Nuclear Information System (INIS)

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

136

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 of the central and two lateral bodies, which are connected by a common velocity field. This approach is similar to two-dimensional stability analyses, where the log spiral potential failure surface...

2012-01-01

137

High Pressure, Earth-Storable Rocket Technology. Volume 3; Appendices C and D  

Science.gov (United States)

The effect of elevated chamber pressure on combustion efficiency and heat transfer has been determined at the 100 lbf (445 N) thrust level for nitrogen tetroxide propellants. Measurements were made up to 500 psia (3.45 MPa) with testbed hardware; tests at 100 psia (0.690 MPa) and 250 psia (1.72 MPa) were made with radiation-cooled rhenium chambers. The first task of the program served to determine desirable thruster applications and operating conditions: high total impulse, i.e. communication satellite or spacecraft bus axial engines, at chamber pressures up to 250 psia (1.72 MPa) pressure-fed, or up to 500 psia (3.45 MPa) pump-fed. The hardware modifications and testing required to obtain the data were determined in Task 2, which included design-support hot fire tests; supplemental hardware, including a 250 psia (1.72 MPa) Pc rhenium chamber and a 20% fuel-film cooled platelet injector was fabricated in Task 3. Testing showed that satisfactory operation of Ir-Re radiation chambers is assured at pressures up to 250 psia and may be possible up to 500. The heat transfer data obtained show good correlation with throat Reynolds number and are generally under values given by the simplified Bartz equation; chambers equilibrium temperatures match predicted values. Preliminary optimization of trip configuration and mixture ratio were made; Isp performance from thrust measurements was within 1% of predicted values. Stability, compatibility, and front-end thermal management were determined to be satisfactory.

Jassowski, D. M.

1997-01-01

138

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

139

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 SciELO Cuba | Language: Spanish 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 desba [...] lance glomérulo-tubular, con preponderancia tubular Aunque el análisis de este último hecho no ha sido como tal abordado en la patogénesis del síndrome hipertensivo. 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-tubu [...] le 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 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.

140

Discover Earth  

Science.gov (United States)

Discover Earth is a NASA-sponsored project for teachers of grades 5-12, designed to: (1) enhance understanding of the Earth as an integrated system; (2) enhance the interdisciplinary approach to science instruction; and (3) provide classroom materials that focus on those goals. Discover Earth is conducted by the Institute for Global Environmental Strategies in collaboration with Dr. Eric Barron, Director, Earth System Science Center, The Pennsylvania State University; and Dr. Robert Hudson, Chair, the Department of Meteorology, University of Maryland at College Park. The enclosed materials: (1) represent only part of the Discover Earth materials; (2) were developed by classroom teachers who are participating in the Discover Earth project; (3) utilize an investigative approach and on-line data; and (4) can be effectively adjusted to classrooms with greater/without technology access. The Discover Earth classroom materials focus on the Earth system and key issues of global climate change including topics such as the greenhouse effect, clouds and Earth's radiation balance, surface hydrology and land cover, and volcanoes and climate change. All the materials developed to date are available on line at (http://www.strategies.org) You are encouraged to submit comments and recommendations about these materials to the Discover Earth project manager, contact information is listed below. You are welcome to duplicate all these materials.

Steele, Colleen

1998-01-01

 
 
 
 
141

Effects of Si on the elastic property of Fe at Earth's inner core pressures: First principles study  

Science.gov (United States)

We investigate the effects of silicon incorporation on the structural stability and elasticity of iron at the Earth's inner core pressures by means of the density functional calculation method in order to clarify the acceptability of silicon to the possible light elements dissolving in the inner core. Calculations show that (1) silicon incorporation enhances the bcc stability field as experimental understandings but hcp phase is the most stable at the inner core pressures even in Fe 0.875Si 0.125, (2) silicon less affects to the elasticity of bcc iron but decreases shear moduli of hcp and fcc phases, (3) it does not drastically change the elastic wave velocities of iron due to the cancellation of associated changes in density and elastic moduli, (4) both P and S wave velocities for each phase and compound linearly depend on the density, and (5) fcc phase is more elastically anisotropic than hcp phase and the anisotropy is enhanced by silicon. We apply two different high-temperature corrections to the wave velocities. Inner core P-wave velocity is well reproduced in the both models, whereas the calculated S-wave velocities significantly depend on the temperature correction. Small effects of silicon on the density-velocity relations are found in both models.

Tsuchiya, Taku; Fujibuchi, Mika

2009-05-01

142

Local structure around rare-earth ions in B{sub 2}O{sub 3} glass at high pressure  

Energy Technology Data Exchange (ETDEWEB)

Melt quenching of B{sub 2}O{sub 3} with less than 25 mol. % rare-earth oxide (RE{sub 2}O{sub 3}) at ambient pressure results in a milky white glass because of liquid-liquid phase separation into B{sub 2}O{sub 3} and RE{sub 2}O{sub 3}{center_dot}3B{sub 2}O phases. In contrast, we have found that melt quenching under GPa-order pressure realizes a transparent RE-doped B{sub 2}O{sub 3} glass. This study investigates the local structure around the RE ions in the B{sub 2}O{sub 3} glass prepared at 3 GPa using optical measurements and electron-spin-echo envelope modulation spectroscopy. It is shown that the RE-rich microparticles disappear and the RE ions are isolated from each other in a highly symmetric crystal field formed by triangular and tetrahedral boron units. This result is consistent with that extrapolated from the data for RE-doped sodium borate glasses.

Funabiki, Fuji [Frontier Research Center, Tokyo Institute of Technology, 4259 Nagatsuta, Yokohama, 226-8503 (Japan); Matsuishi, Satoru [Research Center for Strategic Materials, Tokyo Institute of Technology, 4259 Nagatsuta, Yokohama, 226-8503 (Japan); Hosono, Hideo [Frontier Research Center, Tokyo Institute of Technology, 4259 Nagatsuta, Yokohama, 226-8503 (Japan); Research Center for Strategic Materials, Tokyo Institute of Technology, 4259 Nagatsuta, Yokohama, 226-8503 (Japan); Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Yokohama, 226-8503 (Japan)

2013-06-14

143

Noninvasive Intracranial Pressure and Tissue Oxygen Measurements for Space and Earth  

Science.gov (United States)

The paper discusses the following: Increasing intracranial pressure in humans during simulated microgravity. and near-infrared monitoring of model chronic compartment syndrome in exercising skeletal muscle. Compared to upright-seated posture, 0 deg. supine, 6 deg. HDT, and 15 deg. HDT produced TMD changes of 317 +/- 112, 403 +/- 114, and 474 +/- 112 n1 (means +/- S.E.), respectively. Furthermore, postural transitions from 0 deg. supine to 6 deg. HDT and from 6 deg. to 15 deg. HDT generated significant TMD changes (p less than 0.05). There was no hysteresis when postural transitions to HDT were compared to reciprocal transitions toward upright seated posture. Currently, diagnosis of chronic compartment syndrome (CCS) depends on measurement of intramuscular pressure by invasive catheterization. We hypothesized that this syndrome can be detected noninvasively by near-infrared (NIR) spectroscopy, which tracks variations in muscle hemoglobin/myoglobin oxygen saturation. CCS was simulated in the tibialis anterior muscle of 7 male and 3 female subjects by gradual inflation of a cuff placed around the leg to 40 mmHg during 14 minutes of cyclic isokinetic dorsiflexion exercise. On a separate day, subjects underwent the identical exercise protocol with no external compression. In both cases, tissue oxygenation (T(sub O2) was measured in the tibialis anterior by NIR spectroscopy and normalized to a percentage scale between baseline and a T(sub O2) nadir reached during exercise to ischemic exhaustion. Over the course of exercise, T(sub O2) declined at a rate of 1.4 +/- 0.3% per minute with model CCS, yet did not decrease during control exercise. Post-exercise recovery of T(sub O2) was slower with model CCS (2.5 +/- 0.6 min) than in control (1.3 +/- 0.2 min). These results demonstrate that NIR spectroscopy can detect muscle deoxygenation caused by pathologically elevated intramuscular pressure in exercising skeletal muscle. Consequently, this technique shows promise as a noninvasive diagnostic tool for CCS.

Hargens, A. R.; Ballard, R. E.; Murthy, G.; Watenpaugh, D. E.

1994-01-01

144

The effect of non-stoichiometry at high-pressure: implications for the Earth's mantle mineralogy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A non-stoichiometric sample of spinel with composition T(Mg0.4Al0.6)M(Al1.8?0.2)O4 was investigated by single-crystal X-ray diffraction in situ up to about 8.7 GPa using a diamond anvil cell. The P(V) data were fitted using a third-order Birch–Murnaghan equation of state and the unit-cell volume V0, the bulk modulus KT0 and its first pressure derivative K? were refined simultaneously providing the following coefficients: V0 = 510.34(6) Å3, KT0 = 171(2) GPa, K? = 7.3(6). This KT0 valu...

Bruno, Marco; Prencipe, Mauro

2009-01-01

145

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  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish 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 describ [...] e 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. Abstract in english 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 plai [...] n 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.

146

Investigation of a pressure balancing system for the Stirling engine. Stirling engine ni okeru atsuryoku chosei system no kento  

Energy Technology Data Exchange (ETDEWEB)

On the results of the previous analysis, it was shown that as operation of pressure control circuit assembled at a Stirling engine NS30S reduces its expanding works, and increases its compressing ones, its output and efficiency reduce in comparison with no operation does. And yet, their reasons have not been clarified. In this paper, some variations of pressure, temperature, mass, mass flow, exchangeable heat and working capacity were examined with and without operations of the circuit necesary for the double working four cylinder types of Stirling engine by using cycle simulation codes with third-order method developed by authers. And, the difference occurred by variations of all these factors and effects of the pressure control circuit on behavior of working gas and faculties of engine were followed. Furthermore, calculation results on pressure variation and reduction were also verified in their comparisons. 4 refs., 17 figs., 3 tabs.

Sekiya, H.; Nakazato, T. (Sanyo Electric Co. Ltd., Osaka (Japan))

1991-07-25

147

High-pressure rare earth silicates: Lanthanum silicate with barium phosphate structure, holmium silicate apatite, and lutetium disilicate type X  

International Nuclear Information System (INIS)

The phase relations of a wide selection of rare earth disilicates have been investigated up to 10 GPa and 1700 deg. C using piston cylinder and multi-anvil equipment. Single-crystal X-ray structures have been obtained for the following high-pressure phases: (1) La2.67(SiO4)2: monoclinic, space group C2/m, Z=2, a=9.419(2), b=5.445(1), c=7.214(1) A, ?=115.71(3)o, R=0.042; disordered Ba3(PO4)2 structure type, with 3xb and 7xb superstructures identified. (2) Ho8.67(SiO4)6(OH)2: hexagonal, P63/m, Z=1, a=9.3221(4), c=6.7347(2) A, R=0.026; silicate hydroxyapatite. (3) Lu2Si2O7: tetragonal, P41212, Z=4, a=6.5620(2), c=11.9535(4) A, R=0.023; type X diorthosilicate structure, and the silicate analogue of tetragonal Er2Ge2O7

2005-11-01

148

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

Science.gov (United States)

Objective: 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. Methods: 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. Results: 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. Conclusions: 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

2014-05-01

149

High-pressure syntheses and characterization of the rare-earth fluoride borates RE2(BO3)F3 (RE = Tb, Dy, Ho)  

International Nuclear Information System (INIS)

The new rare-earth fluoride borates RE2(BO3)F3 (RE = Tb, Dy, Ho) were synthesized under high-pressure/high-temperature conditions of 1.5 GPa/1200 C for Tb2(BO3)F3 and 3.0 GPa/900 C for Dy2(BO3)F3 and Ho2(BO3)F3 in a Walker-type multianvil apparatus from the corresponding rare-earth sesquioxides, rare-earth fluorides, and boron oxide. The single-crystal structure determinations revealed that the new compounds are isotypic to the known rare-earth fluoride borate Gd2(BO3)F3. The new rare-earth fluoride borates crystallize in the monoclinic space group P21/c (Z = 8) with the lattice parameters a = 16.296(3), b = 6.197(2), c = 8.338(2) A, ? = 93.58(3) for Tb2(BO3)F3, a = 16.225(3), b = 6.160(2), c = 8.307(2) A, ? = 93.64(3) for Dy2(BO3)F3, and a = 16.189(3), b = 6.124(2), c = 8.282(2) A, ? = 93.69(3) for Ho2(BO3)F3. The four crystallographically different rare-earth cations (CN = 9) are surrounded by oxygen and fluoride anions. All boron atoms form isolated trigonal-planar [BO3]3- groups. The six crystallographically different fluoride anions are in a nearly planar coordination by three rare-earth cations. (orig.)

2013-11-01

150

Balance Problems  

Science.gov (United States)

... it could be a sign of a balance problem. Balance problems can make you feel unsteady or as if ... related injuries, such as hip fracture. Some balance problems are due to problems in the inner ear. ...

151

Achieving high-pressure and high-temperature within a TEM: Crystallographic defects as hosts for concentrating and storing carbon deep within Earth  

Science.gov (United States)

Transmission electron microscopy in combination with in-situ high-pressure and high-temperature measurements is uniquely able to provide high-resolution data about materials under conditions resembling those in Earth's interior. By using nanocontainers of graphitized carbon, it is possible to achieve pressures and temperatures up to 40 GPa and 1200 °C, respectively. A wide range of relatively simple minerals and mineral analogs have been examined using this approach. By studying alpha-PbO2-type titanium dioxide (TiO2) and perovskite-structured nickel-doped lanthanum chromate (LaCr0.5Ni0.5O3), we show the influence of crystallographic defects in concentrating and storing carbon within these analogs to minerals occurring deep inside Earth. Such in-situ observations are impossible by using existing conventional high-pressure techniques. Figure 1. Temporal compression sequence of an anatase nanocrystal with two visible fault planes inside a multi-walled graphitic cage. (a)-(g) The times indicated in each panel are from the start of irradiation. Pressure was generated by shrinkage of the cage resulting from displacement damage by electrons (30 A/cm2) at 770 C. The disappearance of anatase (101) planes and emergence of alpha-PbO2-type TiO2 (110) planes indicates a phase transition between (e) and (f) (see insets).

Wu, J.; Buseck, P. R.

2013-12-01

152

Isolation of the oceanic response to atmospheric pressure forcing in satellite altimetry data using Wiener filtering, and its effects on Earth's rotation  

Science.gov (United States)

The oceanic response to atmospheric pressure forcing is a dynamic one that depends on the frequency and spatial scale of the forcing (Dey & Dickman 2010 J. Geophys. Res.). In this work, the oceanic response is derived from TOPEX satellite altimeter observations (1993 - 2004) on a 4° latitude × 8° longitude grid, corrected for the effects that tides, winds and an annual signal have on the sea-surface height (SSH). The wind correction values are from the ECCO model and were obtained from JPL. The wind correction has been modified by a Darwin correction term to insure ocean-wide mass conservation. For the annual signal, a sinusoid of annual period and the trend over 12 years have been removed at each grid location. Pressure data was downloaded from AER in spherical harmonic form. For each harmonic of forcing, a Wiener filter is used to isolate that portion of the SSH within each gridbox location due to pressure forcing. Wiener filters are designed (Robinson 1967 Multichannel Time Series Analysis) so that the input to the filter produces an 'actual output' which is as close as possible to a specified 'desired output'. The input to the Wiener filter in this work is the corrected SSH time series at each location, and the desired output is the pressure harmonic time series. Based on the reduction in the difference between desired and actual output, achieved by adjusting the filter properties, this technique appears to be successful in isolating that portion of SSH due to individual spherical harmonic pressure coefficients. The pressure-driven portion of the SSH within various frequency bands will be used to calculate the associated oceanic currents, and then the effects of the total response on Earth's rotation. Those effects will be compared with Earth rotation observations and results from other analyses.

Dey, N.; Dickman, S. R.

2013-12-01

153

Melting of Fe and Fe0.9375Si0.0625 at Earth's core pressures studied using ab initio molecular dynamics  

Science.gov (United States)

The issue of melting of pure iron and iron alloyed with lighter elements at high pressure is critical to the physics of the Earth. The iron melting curve in the relevant pressure range between 3 and 4 Mbar is reasonably well established from the theoretical point of view. However, so far no one attempted a direct atomistic simulation of iron alloyed with light elements. We investigate here the impact of alloying the body-centered cubic (bcc) Fe with Si. We simulate melting of the bcc Fe and Fe0.9375Si0.0625 alloy by ab initio molecular dynamics. The addition of light elements to the hexagonal-close-packed (hcp) iron is known to depress its melting temperature (Tm) . We obtain, in marked contrast, that alloying of bcc Fe with Si does not lead to Tm depression; on the contrary, the Tm slightly increases. This suggests that if Si is a typical impurity in the Earth’s inner core, then the stable phase in the core is bcc rather than hcp.

Belonoshko, Anatoly B.; Rosengren, Anders; Burakovsky, Leonid; Preston, Dean L.; Johansson, Börje

2009-06-01

154

3-D force-balanced magnetospheric configurations  

Directory of Open Access Journals (Sweden)

Full Text Available The knowledge of plasma pressure is essential for many physics applications in the magnetosphere, such as computing magnetospheric currents and deriving mag-netosphere-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-3-D code that solves the 3-D force balance equation ${vec J} times {vec B} = nabla P$ computationally. Our calculation is performed in a flux coordinate system in which the magnetic field is expressed in terms of Euler potentials as ${vec B} = nabla psi times nabla alpha$. 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 ? surfaces are imposed using empirical field models. Our results provide 3-D distributions of magnetic field, plasma pressure, as well as parallel and transverse currents for both quiet-time and disturbed magnetospheric conditions.

Key words. Magnetospheric physics (magnetospheric configuration and dynamics; magnetotail; plasma sheet

S. Zaharia

2004-01-01

155

Pressure-induced structural phase transition and elastic properties in rare earth CeBi and LaBi  

International Nuclear Information System (INIS)

A comprehensive first principles study of structural, elastic, electronic and phonon properties of rare-earth CeBi and LaBi is reported within the density functional theory scheme. The ground state properties such as lattice constant, elastic constants, bulk modulus, and finally the phase transition and lattice dynamical properties of rare-earth CeBi and LaBi of rocksalt (B1) and CsCl (B2) structures are determined. The electron band structures for the two phases of both rare-earth crystals are presented. We have calculated phonon dispersion curve, showing that all phonon modes in phonon dispersion curves of B1 phase in CeBi and LaBi are positive, which indicates a stable phase for this structure.

2012-07-30

156

Quantifying the role of fire in the Earth system - Part 2: Impact on the net carbon balance of global terrestrial ecosystems for the 20th century  

Energy Technology Data Exchange (ETDEWEB)

Fire is the primary terrestrial ecosystem disturbance agent on a global scale. It affects carbon balance of global terrestrial ecosystems by emitting carbon to atmosphere directly and immediately from biomass burning (i.e., fire direct effect), and by changing net ecosystem productivity and land-use carbon loss in post-fire regions due to biomass burning and fire-induced vegetation mortality (i.e., fire indirect effect). Here, we provide the first quantitative assessment about the impact of fire on the net carbon balance of global terrestrial ecosystems for the 20th century, and investigate the roles of fire direct and indirect effects. This study is done by quantifying the difference between the 20th century fire-on and fire-off simulations with NCAR community land model CLM4.5 as the model platform. Results show that fire decreases net carbon gain of the global terrestrial ecosystems by 1.0 Pg C yr-1 average across the 20th century, as a results of fire direct effect (1.9 Pg C yr-1) partly offset by indirect effect (-0.9 Pg C yr-1). Fire generally decreases the average carbon gains of terrestrial ecosystems in post-fire regions, which are significant over tropical savannas and part of forests in North America and the east of Asia. The general decrease of carbon gains in post-fire regions is because fire direct and indirect effects have similar spatial patterns and the former (to decrease carbon gain) is generally stronger. Moreover, the effect of fire on net carbon balance significantly declines prior to ~1970 with trend of 8 Tg C yr-1 due to increasing fire indirect effect and increases afterward with trend of 18 Tg C yr-1 due to increasing fire direct effect.

Li, Fang; Bond-Lamberty, Benjamin; Levis, Samuel

2014-03-07

157

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 seventy year old idea of convection in the Earth's fluid core is re...

Herndon, J. Marvin

2009-01-01

158

SPES-2, AP600 intergral system test S01007 2 inch CL to core make-up tank pressure balance line break  

International Nuclear Information System (INIS)

The SPES-2 is a full height, full pressure experimental test facility reproducing the Westinghouse AP600 reactor with a scaling factor of 1/395. The experimental plant, designed and operated by SIET in Piacenza, consists of a full simulation of the AP600 primary core cooling system including all the passive and active safety systems. In 1992, Westinghouse, in cooperation with ENEL (Ente Nazionale per l' Energia Elettrica), ENEA (Enter per le numove Technlogie, l' Energia e l' Ambient), Siet (Societa Informazioni Esperienze Termoidraulich) and ANSALDO developed an experimental program to test the integrated behaviour of the AP600 passive safety systems. The SPES-2 test matrix, concluded in November 1994, has examined the AP600 passive safety system response for a range of small break LOCAs at different locations on the primary system and on the passive system lines; single steam generator tube ruptures with passive and active safety systems and a main steam line break transient to demonstrate the boration capability of passive safety systems for rapid cooldown. Each of the tests has provided detailed experimental results for verification of the capability of the analysis methods to predict the integrated passive safety system behaviour. Cold and hot shakedown tests have been performed on the facility to check the characteristics of the plant before starting the experimental campaign. The paper first presents a description of the SPES-2 test facility then the main results of S01007 test open-quotes 2close quotes Cold Leg (CL) to Core Make-up Tank (CMT) pressure balance line breakclose quotes are reported and compared with predictions performed using RELAP5/mod3/80 obtained by ANSALDO through agreement with U.S.N.R.C. (U.S. Nuclear Regulatory Commission). The SPES-2 nodalization and all the calculations here presented were performed by ANSALDO and sponsored by ENEL as a part of pre-test predictions for SPES-2

1995-09-01

159

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.

Farzin Salmasi

2013-05-01

160

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

 
 
 
 
161

High Pressure Melting, Phase Diagrams, and Equations of State in the Fe-FeSi System with Application to Earth's Core  

Science.gov (United States)

The Earth's core is comprised mostly of iron, with some nickel and several weight percent of one or more light elements. The light element(s) dictate phase relations, structure, and dynamic behaviour, so it is crucial to evaluate various candidates at conditions of planetary interiors. We present results on high P-T phase diagrams and equations of state in the Fe-FeSi system with application to the structure and composition of Earth's core. X-ray diffraction measurements were performed on stoichiometric FeSi and on Fe-Si alloys containing 9 and 16 wt% silicon in a laser-heated diamond anvil cell at the APS, NSLS, and ALS. Pressures were determined from the lattice parameter of KBr. We have investigated the phase diagram of Fe-9Si to 100 GPa and over 3000 K. Our melting curve agrees with previous results on similar alloys [1,2], as demonstrated using multiple methods of detecting melting. Our subsolidus results are similar to those of Lin et al. [3], though we find the B2 structure instead of bcc, and a shallower slope for the hcp+B2 to fcc+B2 boundary. We studied phase relations of Fe-16Si to over 135 GPa, finding agreement with previous melting curves [2,4]. Below 45 GPa, this alloy has the D0_3 structure. At high pressures, Fe-16Si breaks down into a mixture of B2 and hcp phases, with this mixture stable to pressures of the Earth's outer core. This is the first study on the B2 phase of FeSi with in situ X-ray diffraction at high pressures and temperatures. We report a wide B2+B20 two-phase field in FeSi, with complete conversion to the B2 structure by ~42 GPa. A melting experiment on FeSi agrees with the results of Lord et al. [5]. We have synthesized our results with previous studies to construct T-X and P-X phase diagrams, and we have determined thermal equations of state of each alloy. Our measured densities can be used to constrain the maximum amount of silicon in the Earth's outer core by comparison to the equation of state of hcp-Fe [6] and the seismologically-determined density. Assuming a core-mantle boundary (CMB) temperature of 4000 +/- 500 K and a 1-2% density decrease upon melting, the amount of silicon in the outer core required to match PREM at the CMB is 11.3 +/- 1.5 weight percent, under the simplifying assumption of a purely Fe-Ni-Si outer core. The minimum temperature of an Fe-Si outer core is 4380 K, based on the eutectic melting point of Fe-FeSi alloys, and silicon is shown not to significantly depress the melting point of iron at core conditions. At the highest pressures reached, only the hcp and B2 structures are seen in the Fe-FeSi system. We predict that alloys containing more than ~4-8 wt% Si will convert to an hcp+B2 mixture and later to the hcp structure with increasing pressure, and that an iron-silicon alloy in the Earth's inner core would most likely be a mixture of hcp and B2 phases. [1] Kuwayama and Hirose (2004) Am Mineral 89, 273-276 [2] Morard et al. (2011) PCM 38, 767-776 [3] Lin et al (2002) Science 295, 313-315 [4] Asanuma et al. (2010) PCM 37, 353-359 [5] Lord et al. (2010) JGR 115, B06208 [6] Dewaele et al. (2006) PRL 97, 215504

Fischer, R. A.; Campbell, A. J.; Reaman, D. M.; Heinz, D. L.; Dera, P. K.; Prakapenka, V.

2012-12-01

162

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  

Directory of Open Access Journals (Sweden)

Full Text Available 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 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.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 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.

SI Ribas

2007-10-01

163

Pressure-induced valence and structure change in some anti-Th3P4 structure rare earth compounds  

International Nuclear Information System (INIS)

The anti-Th3P4 structure compounds Yb4Bi3 and Yb4Sb3 have been investigated to 350 kbar by high pressure X-ray diffraction, using the diamond anvil cell. From the P-V data it is found that Yb4Bi3 and Yb4Sb3 are much more compressible, compared to Sm4Bi3 before the valence transition. This suggests that a continuous change in the valence state of Yb takes place with pressure in the two compounds and that they may be in the mixed valent state already at ambient pressure. The ''collapsed'' anti-Th3P4 structure becomes unstable in Yb4Bi3 and Yb4Sb3 and new lines appear at high pressure, that fit the NaCl structure. The latter structure change seems to occur also in the electronically collapsed Sm4Bi3. The results are presented and discussed. (Auth.)

1981-08-14

164

Generation of methane in the Earth's mantle: In situ high pressure–temperature measurements of carbonate reduction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present in situ observations of hydrocarbon formation via carbonate reduction at upper mantle pressures and temperatures. Methane was formed from FeO, CaCO3-calcite, and water at pressures between 5 and 11 GPa and temperatures ranging from 500°C to 1,500°C. The results are shown to be consistent with multiphase thermodynamic calculations based on the statistical mechanics of soft particle mixtures. The study demonstrates the existence of abiogenic pathways for the formation of hydrocarbo...

Scott, Henry P.; Hemley, Russell J.; Mao, Ho-kwang; Herschbach, Dudley R.; Fried, Laurence E.; Howard, W. Michael; Bastea, Sorin

2004-01-01

165

New high-pressure and high-temperature metal/silicate partitioning of U and Pb: Implications for the cores of the Earth and Mars  

International Nuclear Information System (INIS)

In order to quantify possible fractionation of U and Pb into a metallic core, we have performed piston cylinder and multi-anvil press experiments at high pressure (up to 20 GPa) and high temperature (up to 2400 degrees C) and obtained the distribution coefficient D(metal-silicate) and the exchange partition coefficient K(metal-silicate) for these elements between metal and silicates (mineral or liquid). DPb(metal-silicate) and DU(metal-silicate) depend strongly on the S content of the metallic phase, and also on the oxygen fugacity, in agreement with an effective valence state of 4 for U in silicates and 2 for Pb in silicates. KdPb( metal-silicate) and KdU(metal-silicate) show no discernable pressure and temperature trend. U remains lithophile even at high pressure and high temperature but its lithophile nature decreases at very low oxygen fugacity. From our experimental data, it was possible to calculate the U and Pb contents of the cores of Mars and Earth under core-mantle equilibrium conditions at high pressure and high temperature. From the D(metal-silicate) of the present study, we obtained that: 0.008 ppm ? Pb (in the core) ? 4.4 ppm, and 0.0003 ppb ? U (in the core) ? 0.63 ppb, depending on whether the metal is S-free or S-saturated respectively, and if the mantle was molten or solid during the segregation process of the Earth's core around ?IW-2. For Mars, based on a core segregation process around ?IW-1, we obtained that: 0.005 ppm ? Pb (in the core) ? 3 ppm, and 0.00002 ppb ? U (in the core) < 0.05 ppb, depending on the metallic composition: S-free or S-saturated respectively. Our results suggest that the low concentration of Pb in the terrestrial mantle could not be explained by an early Pb sequestration in the Earth's core even if S is the dominant light element of the core. If we assume a magma ocean scenario, U might produced a maximum value of 1.5% of the total heat budget of the core with a segregation occurring below ?IW-3. The values found in the present study for U in the Martian core suggest that the magnetic field activity of Mars before ? 0.5 b.y. after its formation would be difficult to ascribe to the decay of U alone. (authors)

2007-01-01

166

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

2012-12-01

167

Balance failure in single limb stance due to ankle sprain injury: An analysis of center of pressure using the fractal dimension method.  

Science.gov (United States)

Instrumented postural control analysis plays an important role in evaluating the effects of injury on dynamic stability during balance tasks, and is often conveyed with measures based on the displacement of the center-of-pressure (COP) assessed with a force platform. However, the desired outcome of the task is frequently characterized by a loss of dynamic stability, secondary to injury. Typically, these failed trials are discarded during research investigations, with the potential loss of informative data pertaining to task success. The novelty of the present study is that COP characteristics of failed trials in injured participants are compared to successful trial data in another injured group, and a control group of participants, using the fractal dimension (FD) method. Three groups of participants attempted a task of eyes closed single limb stance (SLS): twenty-nine participants with acute ankle sprain successfully completed the task on their non-injured limb (successful injury group); twenty eight participants with acute ankle sprain failed their attempt on their injured limb (failed injury group); sixteen participants with no current injury successfully completed the task on their non-dominant limb (successful non-injured group). Between trial analyses of these groups revealed significant differences in COP trajectory FD (successful injury group: 1.58±0.06; failed injury group: 1.54±0.07; successful non-injured group: 1.64±0.06) with a large effect size (0.27). These findings demonstrate that successful eyes-closed SLS is characterized by a larger FD of the COP path when compared to failed trials, and that injury causes a decrease in COP path FD. PMID:24746034

Doherty, Cailbhe; Bleakley, Chris; Hertel, Jay; Caulfield, Brian; Ryan, John; Delahunt, Eamonn

2014-05-01

168

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 increases monotonically with increasing lattice parameter from 244(3) K for TmTe_3 to 416(3) K for SmTe_3. The heaviest members of the series, R = Dy, Ho, Er, Tm, are observed to have a second transition at a lower temperature, which ma...

Ru, N.; Condron, C. L.; Margulis, G. Y.; Shin, K. Y.; Laverock, J.; Dugdale, S. B.; Toney, M. F.; Fisher, I. R.

2006-01-01

169

Orbital dynamics of high area-to-mass ratio spacecraft with J2 and solar radiation pressure for novel Earth observation and communication services  

Science.gov (United States)

This paper investigates the effect of planetary oblateness and solar radiation pressure on the orbits of high area-to-mass spacecraft. A planar Hamiltonian model shows the existence of equilibrium orbits with the orbit apogee pointing towards or away from the Sun. These solutions are numerically continued to non-zero inclinations and considering the obliquity of the ecliptic plane relative to the equator. Quasi-frozen orbits are identified in eccentricity, inclination and the angle between the Sun-line and the orbit perigee. The long-term evolution of these orbits is then verified through numerical integration. A set of 'heliotropic' orbits with apogee pointing in the direction of the Sun is proposed for enhancing imaging and telecommunication on the day side of the Earth. The effects of J2 and solar radiation pressure are exploited to obtain a passive rotation of the apsides line following the Sun; moreover the effect of solar radiation pressure enables such orbits at higher eccentricities with respect to the J2 only case.

Colombo, Camilla; Lücking, Charlotte; McInnes, Colin R.

2012-12-01

170

Effect of Chemical Pressure on the Charge Density Wave Transition in Rare-Earth Tritellurides RTe3  

Energy Technology Data Exchange (ETDEWEB)

The charge density wave transition is investigated in the bilayer family of rare-earth tritelluride RTe{sub 3} compounds (R=Sm, Gd, Tb, Dy, Ho, Er, and Tm) via high-resolution x-ray diffraction and electrical resistivity. The transition temperature increases monotonically with increasing lattice parameter from 244(3) K for TmTe{sub 3} to 416(3) K for SmTe{sub 3}. The heaviest members of the series, R=Dy, Ho, Er, and Tm, are observed to have a second transition at a lower temperature, which marks the onset of an additional charge density wave with wave vector almost equal in magnitude to the first, but oriented in the perpendicular direction.

Ru, N.; Condron, C.L.; Margulis, G.Y.; Shin, K.Y.; Laverock, J.; Dugdale, S.B.; Toney, M.F.; Fisher, I.R.; /Stanford U., Appl. Phys. Dept. /SLAC, SSRL /Bristol U.

2009-04-30

171

The effect of compression on Individual Pressure Vessel Nickel/Hydrogen components. [for energy storage in low earth orbits  

Science.gov (United States)

Compression tests were performed on representative Individual Pressure Vessel (IPV) Nickel/Hydrogen cell components in an effort to better understand the effects of force on component compression and the interactions of components under compression. It appears that the separator is the most easily compressed of all of the stack components. It will typically partially compress before any of the other components begin to compress. The compression characteristics of the cell components in assembly differed considerably from what would be predicted based on individual compression characteristics. Component interactions played a significant role in the stack response to compression. The results of the compression tests were factored into the design and selection of Belleville washers added to the cell stack to accommodate nickel electrode expansion while keeping the pressure on the stack within a reasonable range of the original preset.

Manzo, Michelle A.; Perez-Davis, Marla E.

1988-01-01

172

Low pressure ion chromatography with a low cost paired emitter-detector diode based detector for the determination of alkaline earth metals in water samples  

Energy Technology Data Exchange (ETDEWEB)

The use of a low pressure ion chromatograph based upon short (25 mm x 4.6 mm) surfactant coated monolithic columns and a low cost paired emitter-detector diode (PEDD) based detector, for the determination of alkaline earth metals in aqueous matrices is presented. The system was applied to the separation of magnesium, calcium, strontium and barium in less than 7 min using a 0.15 M KCl mobile phase at pH 3, with post-column reaction detection at 570 nm using o-cresolphthalein complexone. A comparison of the performance of the PEDD detector with a standard laboratory absorbance detector is shown, with limits of detection for magnesium and calcium using the low cost PEDD detector equal to 0.16 and 0.23 mg L{sup -1}, respectively. Finally, the developed system was used for the determination of calcium and magnesium in a commercial spring water sample.

Barron, Leon [National Centre for Sensor Research, School of Chemical Sciences, Dublin City University, Glasnevin, Dublin 9 (Ireland); Nesterenko, Pavel N. [National Centre for Sensor Research, School of Chemical Sciences, Dublin City University, Glasnevin, Dublin 9 (Ireland); Diamond, Dermot [National Centre for Sensor Research, School of Chemical Sciences, Dublin City University, Glasnevin, Dublin 9 (Ireland); O' Toole, Martina [National Centre for Sensor Research, School of Chemical Sciences, Dublin City University, Glasnevin, Dublin 9 (Ireland); Lau, King Tong [National Centre for Sensor Research, School of Chemical Sciences, Dublin City University, Glasnevin, Dublin 9 (Ireland); Paull, Brett [National Centre for Sensor Research, School of Chemical Sciences, Dublin City University, Glasnevin, Dublin 9 (Ireland)]. E-mail: brett.paull@dcu.ie

2006-09-01

173

High-Pressure High-Temperature Equation of State of B1 Cobalt Oxide and Implications for Redox Relations in the Earth's Lower Mantle  

Science.gov (United States)

First row transition metals play important roles in the Earth's mantle by influencing minerals' phase stability, density and elastic properties, and helping to govern defect-mediated behavior including electrical and thermal conductivity, and rheology. Since transition metals are also somewhat siderophile, geochemical measurements of absolute and relative abundances of transition metals in mantle-derived rocks helps constrain the evolution of the core/mantle system, including initial segregation and continuing reactions. Interpreting the geochemical record in terms of partitioning of transition metals among oxide and metal phases requires measurements of thermoelastic properties of the oxide and metal phases at the high pressure and temperature conditions of the Earth's interior. The high pressure and temperature equation of state of rocksalt-structured cobalt oxide was measured up to 65 GPa and 2600 K using synchrotron X-ray diffraction in conjunction with the laser heated diamond anvil cell. We determine the best fit equation of state parameters to be V0=77.4 (fixed) Å3, K0T=190 (1) GPa, dK/dP =3.49 (4), ?0=1.54 (4), q=2.87 (15), and ?0=517.8 (fixed), using a Mie-Gruneisen-Debye parameterization. We use these values in conjunction with existing measurements of the cobalt metal equation of state to calculate chemical free energy differences between the cobalt oxide and cobalt metal phases as a function of pressure and temperature. A comparison of the Co/CoO with Ni/NiO system energetics (Campbell et al. 2009) predicts a crossing point at 55 GPa and 2000 K. This energy crossing point in energy can be mapped as a crossing point in electrochemical potential of the two metal ions, suggesting that the Ni becomes more siderophile than Co as pressure and temperature increases. This result is in good agreement with existing measurements of Ni and Co partition coefficients between mantle and core materials (O'Neill et al. 1998; Bouhifd and Jephcoat 2011).

Kavner, A.; Armentrout, M. M.

2012-12-01

174

High-pressure polymorphism of Fe[subscript 2]P and its implications for meteorites and Earth's core  

Energy Technology Data Exchange (ETDEWEB)

Minerals with composition (Fe,Ni){sub 2}P, are rare, though important accessory phases in iron and chondritic meteorites. The occurrence of these minerals in meteorites is believed to originate either from the equilibrium condensation of protoplanetary materials in solar nebulae or from the later accretion and condensation processes in the cores of parent bodies. Fe-Ni phosphides are considered a possible candidate for a minor phase present in the Earth's core, and at least partially responsible for the observed density deficit with respect to pure iron. We report results of high-pressure high-temperature X-ray diffraction experiments with synthetic barringerite (Fe{sub 2}P) up to 40 GPa and 1400 K. A new phase transition to the Co{sub 2}Si-type structure has been found at 8.0 GPa, upon heating. The high-pressure phase can be metastably quenched to ambient conditions at room temperature, and then, if heated again, transforms back to barringerite, providing an important constraint on the thermodynamic history of meteorite.

Dera, P.; Lavina, B.; Borkowski, L.A.; Prakapenka, V.B.; Sutton, S.R.; Rivers, M.L.; Downs, R.T.; Boctor, N.Z.; Prewitt, C.T. (UNLV); (UofC); (Univ of AZ); (CIW)

2008-05-19

175

Balance Checklist  

Science.gov (United States)

... Clinical Exercise Specialist CSU FallPROOF Balance & Mobility Specialist Pilates Institute of America Exercise Director, Parkinson Association of ... be improved with abdominal and back exercises or Pilates mat work. Lower body and ankle flexibility, which ...

176

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

177

Microstructual investigation of mixed rar earth iron boron processed vis melt-spinning and high-pressure gas-atomization for isotrophic bonded permanent magnets  

Energy Technology Data Exchange (ETDEWEB)

A solid solution of three rare earths (RE) in the RE{sub 2}Fe{sub 14}B structure have been combined to create the novel mixed rare earth iron boron (MRE{sub 2}Fe{sub 14}B) alloy family. MRE{sub 2}Fe{sub 14}B exhibits reduced temperature dependent magnetic properties; remanence and coercivity. The desired form of MRE{sub 2}Fe{sub 14}B is a powder that can be blended with a polymer binder and compression or injection molded to form an isotropic polymer bonded permanent magnet (PBM). Commercially, Nd{sub 2}Fe{sub 14}B is the alloy of choice for PBMs. Powders of Nd{sub 2}Fe{sub 14}B are made via melt-spinning as can be MRE{sub 2}Fe{sub 14}B which allows for direct comparisons. MRE{sub 2}Fe{sub 14}B made using melt-spinning at high wheel speeds is overquenched and must be annealed to an optimal hard magnetic state. Due to the rare earth content in the MRE{sub 2}Fe{sub 14}B powders, they must be protected from the environment in which they operate. This protection is accomplished by using a modified fluidized bed process to grow a protective fluoride coating nominally 15nm thick, to reduce air oxidation. MRE{sub 2}Fe{sub 14}B has demonstrated reduced temperature dependent magnetic properties in ribbon and PBM form. The real challenge has been modifying alloy designs that were successfully melt-spun to be compatible with high-pressure gas-atomization (HPGA). The cooling rates in HPGA are lower than melt-spinning, as the powders are quenched via convective cooling, compared to melt-spinning, which quenches initially by conductive cooling. Early alloy designs, in gas atomized and melt-spun form, did not have similar phase compositions or microstructures. Alloy additions, such as the addition of zirconium as a nucleation catalyst, were successful in creating similar phases and microstructures in the HPGA powders and melt-spun ribbon of the same MRE{sub 2}Fe{sub 14}B composition.

Buelow, Nicholas Lee

2005-08-01

178

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

179

Work-Life Balance: Beyond the Rhetoric.  

Science.gov (United States)

The principle at stake here says that there should be a balance between an individual's work and their life outside work, and that this balance should be healthy. At the very least, the balance should not be unhealthy. In today's highly pressurized workpl...

J. Kodz H. Harper S. Dench

2002-01-01

180

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

 
 
 
 
181

Coupled Orbit-Attitude Dynamics of High Area-to-Mass Ratio (HAMR) Objects: Influence of Solar Radiation Pressure, Earth's Shadow and the Visibility in Light Curves  

CERN Document Server

The orbital and attitude dynamics of uncontrolled Earth orbiting objects are perturbed by a variety of sources. In research, emphasis has been put on operational space vehicles. Operational satellites typically have a relatively compact shape, and hence, a low area-to-mass ratio (AMR), and are in most cases actively or passively attitude stabilized. This enables one to treat the orbit and attitude propagation as decoupled problems, and in many cases the attitude dynamics can be neglected completely. The situation is different for space debris objects, which are in an uncontrolled attitude state. Furthermore, the assumption that a steady-state attitude motion can be averaged over data reduction intervals may no longer be valid. Additionally, a subset of the debris objects have significantly high area-to-mass ratio values, resulting in highly perturbed orbits, e.g. by solar radiation pressure, even if a stable AMR value is assumed. This assumption implies a steady-state attitude such that the average cross-sect...

Frueh, Carolin; Kelecy, Thomas

2013-01-01

182

Production balance  

International Nuclear Information System (INIS)

In terms of the environment, the year 2011 was balanced in the company Slovenske elektrarne. The trend of a high share of electricity production from nuclear and hydro power plants persisted; therefore, a greater part of electricity supplies (88.5%) was not loaded by emissions of harmful substances into the atmosphere. (author)

2012-04-01

183

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 ...

184

Estudo da sinterização da zircônia dopada com óxidos de terras raras a 5 GPa de pressão Sintering of rare earth-doped zirconia under 5 GPa pressure  

Directory of Open Access Journals (Sweden)

Full Text Available A zircônia (ZrO2 tem mostrado grande destaque entre as cerâmicas avançadas, atraindo muito o interesse de pesquisadores em seus vários campos de atuação. A zircônia apresenta elevada resistência quando na fase tetragonal, mas a fase estável a temperatura ambiente é a monoclínica, sendo necessário o uso de estabilizantes para a fase tetragonal. Neste trabalho propomos a sinterização rápida da zircônia parcialmente estabilizada com óxidos de terras raras (ZrO2-OTR, mediante o emprego da alta pressão de 5 GPa. As condições de sinterização realizadas neste trabalho são inovadoras, haja visto que utilizou-se de tecnologia alternativa para processar a ZrO2-OTR, chamada de altas temperaturas e altas pressões (HPHT. Foi utilizada uma pressão de 5 GPa, temperaturas de 1100, 1200 e 1300 ºC nos tempos de 2 e 5 min. O melhor resultado foi obtido nas amostras sinterizadas a 5 GPa/1300 ºC/5 min, onde apresentaram microdureza média de 488,73 kgf/mm², para uma tenacidade à fratura de 5,33 MPa.m½, as quais apresentaram densidade da ordem de 97,88% da teórica, e 88% em volume de fase tetragonal retida à temperatura ambiente.Zirconia (ZrO2 has shown great projection among the advanced ceramics, attracting the interest of researchers in its various fields of application. Tetragonal zirconia presents high mechanical strength, but the room temperature stable phase is the monoclinic, being necessary the use of stabilizers for obtaining the tetragonal phase. In this work the rapid sintering of zirconia partially stabilized with rare earth oxides (ZrO2-OTR, via 5 GPa high pressure is proposed. The sintering conditions employed in this work are innovative, due to the use of an alternative technology to process ZrO2-OTR, so called high temperature - high pressure (HPHT. A pressure of 5 GPa and temperatures of 1100, 1200 and 1300 ºC for times of 2 and 5 min were used. The best results were obtained for samples sintered at 5 GPa at 1300 ºC/5 min., where a micro-hardness of 488,73 kgf/mm², a fracture toughness of 5,33 MPa.m½, a density of 97,88%, and a 88vol.% of tetragonal phase retained at room temperature were achieved.

C. Kuranaga

2005-06-01

185

Balancing Stick  

Science.gov (United States)

This activity from the provides a demonstration of the relationship between an objectâÂÂs center of gravity and its angular momentum. One attempts to balance a stick with a piece of clay stuck to it in various locations. The site supplies an explanation of the physics that occurs along with suggestions for a contest. Materials needed and assembly instructions are also given. This activity is part of Exploratorium's Science Snacks series.

2008-06-18

186

Lesson "Balance in Nature  

Science.gov (United States)

Lesson "Balance in Nature" This simulation game-lesson (Balance in Nature) gives an opportunity for the students to show creativity, work independently, and to create models and ideas. It creates future-oriented thought connected to their experience, allowing them to propose solutions for global problems and personal responsibility for their activities. The class is divided in two teams. Each team chooses questions. 1. Question: Pollution in the environment. 2. Question: Care for nature and climate. The teams work on the chosen tasks. They make drafts, notes and formulate their solutions on small pieces of paper, explaining the impact on nature and society. They express their points of view using many different opinions. This generates alternative thoughts and results in creative solutions. With the new knowledge and positive behaviour defined, everybody realizes that they can do something positive towards nature and climate problems and the importance of individuals for solving global problems is evident. Our main goal is to recover the ecological balance, and everybody explains his or her own well-grounded opinions. In this work process the students obtain knowledge, skills and more responsible behaviour. This process, based on his or her own experience, dialogue and teamwork, helps the participant's self-development. Making the model "human? nature" expresses how human activities impact the natural Earth and how these impacts in turn affect society. Taking personal responsibility, we can reduce global warming and help the Earth. By helping nature we help ourselves. Teacher: Veselina Boycheva-Chapanova " Saint Patriarch Evtimii" Scholl Str. "Ivan Vazov"-19 Plovdiv Bulgaria

Chapanova, V.

2012-04-01

187

X-ray Raman scattering study of MgSiO3 glass at high pressure: Implication for triclustered MgSiO3 melt in Earth's mantle  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Silicate melts at the top of the transition zone and the core-mantle boundary have significant influences on the dynamics and properties of Earth's interior. MgSiO3-rich silicate melts were among the primary components of the magma ocean and thus played essential roles in the chemical differentiation of the early Earth. Diverse macroscopic properties of silicate melts in Earth's interior, such as density, viscosity, and crystal-melt partitioning, depend on their electronic and short-range loc...

Lee, Sung Keun; Lin, Jung-fu; Cai, Yong Q.; Hiraoka, Nozomu; Eng, Peter J.; Okuchi, Takuo; Mao, Ho-kwang; Meng, Yue; Hu, Michael Y.; Chow, Paul; Shu, Jinfu; Li, Baosheng; Fukui, Hiroshi; Lee, Bum Han; Kim, Hyun Na

2008-01-01

188

Chaotic behavior in a system simulating the pressure balanced injection system. Analysis of passive safety reactor behavior. JAERI's nuclear research promotion program, H12-012 (Contract research)  

Energy Technology Data Exchange (ETDEWEB)

The pressure Balanced Injection System (PBIS) was proposed in a passive safety reactor. Pressurizing Line (PL) connects the Reactor Vessel (RV) and the gas area in the Contain Vessel (CV), and Injected Line (IL) connects two vessels at relatively lower position. In an accident, the two lines are passively opened. The vapor generated by the residual heat pressed downward the water level in the RV. When the level is lower than the inlet of the PL, vapor is ejected into the CV through the PL attaining the pressure balance between the vessels. Then boron water in the CV is injected into the RV through the IL by the static head. This process is repeated by the succeeding vapor generation. In an experiment, the oscillating system was replaced by water column in a U-shaped duct. The vapor generation was simulated by cover gas supply to one end of the duct, while the other end was open to the atmosphere. When the water level reached a certain level, electromagnetic valves opened and the cover gas was ejected. The gas pressure decreased rapidly, resulting in a surface rise. When the water level reached another level, the valves closed. The cover gas pressure increased again, thus, gas ejection occurred intermittently. The interval of the gas ejection was not constant but fluctuated widely. Mere stochastic noise could hardly explain the large amplitude. Then was expressed the system using a set of linear equations. Various types of piecewise linear model were developed to examine the cause of the fluctuation. There appeared tangential bifurcation, period-doubling bifurcation, period-adding bifurcation and so on. The calculated interval exhibited chaotic features. Thus the cause of the fluctuation can be attributed to chaotic features of the system having switching. Since the piecewise linear model was highly simplified the behavior, a quantitative comparison between the calculation and the experiment was difficult. Therefore, numerical simulation code considering nonlinear effect was developed to describe the system behavior in the case there was no stochastic noise. The comparison between the simulation and the experiment revealed that there are some bifurcation-like phenomena being not real bifurcations. Real bifurcations are discovered in the simulation as well as in the experiment. Confirmation of chaotic behavior of the system in the experiment is a subject for a future study. (author)

Madarame, Haruki; Okamoto, Koji; Tanaka, Gentaro; Morimoto, Yuichiro [Tokyo Univ., School of Engineering, Tokyo (Japan); Sato, Akira [Yamagata Univ., Faculty of Engineering, Yonezawa, Yamagata (Japan); Kondou, Masaya [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

2003-03-01

189

High-pressure syntheses and characterization of the rare-earth fluoride borates RE{sub 2}(BO{sub 3})F{sub 3} (RE = Tb, Dy, Ho)  

Energy Technology Data Exchange (ETDEWEB)

The new rare-earth fluoride borates RE{sub 2}(BO{sub 3})F{sub 3} (RE = Tb, Dy, Ho) were synthesized under high-pressure/high-temperature conditions of 1.5 GPa/1200 C for Tb{sub 2}(BO{sub 3})F{sub 3} and 3.0 GPa/900 C for Dy{sub 2}(BO{sub 3})F{sub 3} and Ho{sub 2}(BO{sub 3})F{sub 3} in a Walker-type multianvil apparatus from the corresponding rare-earth sesquioxides, rare-earth fluorides, and boron oxide. The single-crystal structure determinations revealed that the new compounds are isotypic to the known rare-earth fluoride borate Gd{sub 2}(BO{sub 3})F{sub 3}. The new rare-earth fluoride borates crystallize in the monoclinic space group P2{sub 1}/c (Z = 8) with the lattice parameters a = 16.296(3), b = 6.197(2), c = 8.338(2) A, {beta} = 93.58(3) for Tb{sub 2}(BO{sub 3})F{sub 3}, a = 16.225(3), b = 6.160(2), c = 8.307(2) A, {beta} = 93.64(3) for Dy{sub 2}(BO{sub 3})F{sub 3}, and a = 16.189(3), b = 6.124(2), c = 8.282(2) A, {beta} = 93.69(3) for Ho{sub 2}(BO{sub 3})F{sub 3}. The four crystallographically different rare-earth cations (CN = 9) are surrounded by oxygen and fluoride anions. All boron atoms form isolated trigonal-planar [BO{sub 3}]{sup 3-} groups. The six crystallographically different fluoride anions are in a nearly planar coordination by three rare-earth cations. (orig.)

Hinteregger, Ernst; Pitscheider, Almut; Wurst, Klaus; Heymann, Gunter; Huppertz, Hubert [Innsbruck Univ. (Austria). Inst. fuer Allgemeine, Anorganische und Theoretische Chemie; Enders, Michael [Innsbruck Univ. (Austria). Inst. fuer Pharmazie

2013-11-15

190

Induction of heme oxygenase-1 shifts the balance from proinjury to prosurvival in the placentas of pregnant rats with reduced uterine perfusion pressure  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Placental hypoxia/ischemia has been implicated as a central factor in the development of preeclampsia. One particularly useful animal model to study the impact of placental ischemia is the reduced uterine perfusion pressure (RUPP) model. We have previously demonstrated that RUPP animals exhibit elevated placental oxidative stress, which plays an important role in the development of the associated maternal hypertension. Recently, we have demonstrated that cobalt protoporphyrin (CoPP)-mediated ...

George, Eric M.; Arany, Istvan

2012-01-01

191

Investigation of electron parallel pressure balance in the scrape-off layer of deuterium-based radiative divertor discharges IN DIII-D  

International Nuclear Information System (INIS)

Electron density, temperature, and parallel pressure measurements at several locations along field lines connecting the midplane scrapeoff layer (SOL) with the outer divertor are presented for both attached and partially-detached divertor cases: I_p = 1.4 MA, q_9_5 = 4.2, and P_i_n_p_u_t ? 6.7 MW under ELMing H-mode conditions. At the onset of the Partially Detached Divertor (PDD), a high density, low temperature plasma forms in the divertor SOL (divertor MARFE). The electron pressure drops by a factor of ? 2 between the midplane separatrix and the X-point, and then an additional ?3--5 times between the X-point and the outboard separatrix strike point. These results are in contrast to the attached (non-PDD) case, where electron pressure in the SOL is reduced by, at most, a factor of two between the midplane and the divertor target. Divertor MARFEs generally have only marginal adverse impact on important H-mode characteristics, such as confinement time. In fact, PDD discharges at low input power maintains good H-mode characteristics until a high density, low temperature plasma abruptly forms inside the separatrix near the X-point (X-point MARFE). Concurrent with the appearance of this X-point MARFE is a degradation in both energy confinement and the plasma fueling rate, and an increase in the carbon impurity concentration inside the core plasma. The formation of the X-point MARFE is consistent with a thermal instability resulting from the temperature dependence of the carbon radiative cooling rate in the range ? 7--30 eV

1996-05-20

192

Modern rotor balancing - Emerging technologies  

Science.gov (United States)

Modern balancing methods for flexible and rigid rotors are explored. Rigid rotor balancing is performed at several hundred rpm, well below the first bending mode of the shaft. High speed balancing is necessary when the nominal rotational speed is higher than the first bending mode. Both methods introduce weights which will produce rotor responses at given speeds that will be exactly out of phase with the responses of an unbalanced rotor. Modal balancing seeks to add weights which will leave other rotor modes unaffected. Also, influence coefficients can be determined by trial and error addition of weights and recording of their effects on vibration at speeds of interest. The latter method is useful for balancing rotors at other than critical speeds and for performing unified balancing beginning with the first critical speed. Finally, low-speed flexible balancing permits low-speed tests and adjustments of rotor assemblies which will not be accessible when operating in their high-speed functional configuration. The method was developed for the high pressure liquid oxygen turbopumps for the Shuttle.

Zorzi, E. S.; Von Pragenau, G. L.

1985-01-01

193

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

194

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  

International Nuclear Information System (INIS)

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

1998-01-01

195

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

196

Effect of rare earth on lattice size and equilibrium hydrogen pressure for AB5-type MmNi3.55Co0.75Al0.30Mn0.40  

International Nuclear Information System (INIS)

We investigated the effect of rare earth in Mm (misch metal) to crystal structure and hydrogenation properties especially lattice size and equilibrium hydrogen pressure in MmNi3.55Co0.75Al0.30Mn0.40 using X-ray diffraction (XRD) and pressure-composition (P-C) isotherms measurements. We successfully prepared the alloys, where Mm was composed of MxLa0.81-xNd0.14Pr0.05 (Mx = Ce0.47, Y0.40, Gd0.25, Tm0.20, Lu0.16). The substitution amount for each alloy was adjusted to appear stoichiometric single phase and to keep the same lattice volume considering atomic radius of each rare earth element. Among these alloys, however, the Ce containing ones studied showed different characteristics in terms of anisotropy of lattice parameters and equilibrium hydrogen pressure to others. All alloys studied showed the same reversible hydrogen content. Significant difference of the enthalpy and entropy of hydride formation have not been observed

2008-07-14

197

The formation of the wall region - Consequences in the near earth magnetotail  

Science.gov (United States)

This paper discusses important new findings obtained from global kinetic simulations of magnetotail plasma. A region of strongly nonadiabatic ion acceleration (known as the wall region) exists in the near earth tail and demarcates two very different regimes of ion motion: adiabatic and quasi-adiabatic. A strong enhancement of the cross-tail current occurs on the tailward side of the wall. A comparison of numerical and adiabatic pressure profiles indicates that nonadiabatic processes operating in this region may contribute significantly to a pressure balance relief in the course of quasi-steady magnetospheric convection.

Ashour-Abdalla, Maha; Zelenyi, Lev M.; Bosqued, Jean-Michel; Peroomian, Vahe; Wang, Zhi; Schriver, David; Richard, Robert L.

1992-01-01

198

Mars, earth, and ice  

International Nuclear Information System (INIS)

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 CO2 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 CO2 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 CO2 have gone are considered

1986-01-01

199

Balanced Mind Foundation  

Science.gov (United States)

... Parent Network: Our Mission Get Started eNews Balanced Mind Updates Mar. 26, 2014 DBSA March eUpdate: Raising ... Year of Thriving' Program Highlights (Video) Follow Balanced Mind Parent Network Updates: Balanced Mind Parent Network Updates ...

200

High-pressure study of the anomalous rare-earth ternaries Eu/sub 1. 2/Mo/sub 6/S/sub 8/ and Eu/sub 1. 2/Mo/sub 6/Se/sub 8/  

Energy Technology Data Exchange (ETDEWEB)

The two anomalous rare-earth ternaries Eu/sub 1.2/Mo/sub 6/S/sub 8/ and Eu/sub 1.2/Mo/sub 6/Se/sub 8/ are investigated both resistively and magnetically under hydrostatic pressure up to approx.18 kbar. Superconductivity with an onset temperature approx.11 K was observed abruptly at pressure above approx.7 kbar in Eu/sub 1.2/Mo/sub 6/S/sub 8/. However, no superconductivity was detected in Eu/sub 1.2/Mo/sub 6/Se/sub 8/ down to 1.2 K and up to 18 kbar. Several possibilities are discussed and contrasted.

Chu, C.W.; Huang, S.Z.; Lin, C.H.; Meng, R.L.; Wu, M.K.; Schmidt, P.H.

1981-01-26

 
 
 
 
201

A Balancing Act: A Quantitative Analysis of the Influence of Work/Life Balance and Work Atmosphere on Personal and Professional Success of Women Scientists  

Science.gov (United States)

Despite an increase in advanced degrees awarded to women in the geosciences, scientific leaders in academia remain dominantly male. Women are underrepresented in tenure-track positions in Earth science departments at research universities and are less likely to have more senior positions within their academic institutions. Our empirical study analyzes factors that influence personal and professional success for women scientists. Prior research has shown that women are subjected to unintended and unrecognized biases that can have an ultimate impact on their productivity, advancement, and success. We used an electronic survey to collect data from 662 early-career geoscientists who are members of the Earth Science Women's Network and/or the network's Earth Science Jobs list. We asked respondents to self-report their perceptions of work/life balance, professional atmosphere and other variables indicative and/or predictive of personal and professional success. In a previous analysis (Kogan & Laursen, 2011) we found that women consistently rated the professional atmosphere in their departments and their interactions with colleagues less favorably than men. Women indicated lower rates of collaboration with colleagues in their unit compared to their male peers. We also found work/life balance is of particular concern to early-career scientists, especially since tenure clock and the biological clock function on similar timetables. Women reported more caregiving responsibilities than men, further complicating the balance between work and personal life. We hypothesize that the work life balance and professional atmosphere influences productivity, advancement, and career/job satisfaction. We now investigate how work/life balance, atmosphere within the work unit, and mentoring influence productivity, job and career satisfaction, and career advancement. We introduce a structural equation model that seeks to explain how these relationships vary dependent upon gender, career level, caretaking responsibilities, and other variables. Our data indicate strong positive correlations between professional climate and job satisfaction, and between work/life balance and productivity. Our results suggest that the uneven pressures experienced by women influence their ability to achieve personal and professional success. However, our model implies that positive changes in women's work/life balance and professional atmosphere have the potential to help them become more successful both professionally and personally.

Archie, T.; Laursen, S. L.; Kogan, M.

2012-12-01

202

A Reconciled Estimate of Ice-Sheet Mass Balance  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Shepherd, A.; Ivins, E. R.; A, G.; Barletta, V. R.; Bentley, M. J.; Bettadpur, S.; Briggs, K. H.; Bromwich, D. H.; Forsberg, R.; Galin, N.; Horwath, M.; Jacobs, S.; Joughin, I.; King, M. A.; Lenaerts, J. T. M.

2012-01-01

203

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

204

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

2011-01-01

205

A hypothesis of earth quake  

CERN Document Server

Without a model, it is impossible for a geophysicist to study the possibility of forecasting earth quakes. In order to make a simple model, we make a hypothesis of earth quakes. The hypothesis is: (i) There are two kinds of earth quakes, one is the triggered breaking (earth quake), the other is spontaneous breaking (earth quake). (ii) Most major quakes in continental plates Eurasian Plate, North America Plate, South America Plate, Africa Plate and Australia Plate are triggered breaking. (iii) These triggered quakes are triggered by the movements of high pressure centers and low pressure centers of the atmosphere on continental plates. (iv) How can the movements of the high pressure centers trigger a quake? It depends on the extent of the high pressure center and the speed of the movement. Here, we stress high pressure center instead of low pressure center because it is dominated by high pressure center mostly. Of course, the boundary of the plates must have stored enough energy to have quakes, that is, near t...

Tsai, Yeong-Shyeong

2008-01-01

206

Rare earths  

International Nuclear Information System (INIS)

Rare earth elements are commonly extracted from the minerals monazite, bastnaesite, and xenotine. New uses for these elements are constantly developing; they have found applications in glass polishing, television tube phosphors, high-strength low-alloy steels, magnets, catalysts, refractory ceramics, and hydrogen sponge alloys. In Canada, rare earths have been produced as byproducts of the uranium mining industry, but there was no production of rare earths in 1978 or 1979. The world sources of and markets for the rare earth elements are discussed

1979-01-01

207

Functional balance tests  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 balan...

2012-01-01

208

Earth energy  

Energy Technology Data Exchange (ETDEWEB)

Earth energy was described as Canada`s underground economy whose identity was poorly understood. This was shown by the diversity of names used such as geothermal, earth energy, conservation, heat pumps, heat recovery and heat storage. In Canada, 32,000 earth systems were operating in 1995, with a total of 416 MW installed. Major installations are found in the Museum of Civilization in Hull, Carleton University in Ottawa, and some 60 of the largest school buildings in Ontario. Earth energy was considered to be highly efficient and able to reduce the emission of greenhouse gases. It currently accounts for an annual reduction of 90,000 tonnes of CO{sub 2} annually. Canada is recognized as being among the leaders in earth energy technology. It should take advantage of the opportunities provided by NAFTA and enter the U.S. market aggressively and with confidence.

Scott-Smith, P.

1995-12-31

209

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

210

Effects of near-Earth stochastic acceleration and reflections of magnetotail ions on the formation of auroral arcs  

Science.gov (United States)

Findings obtained from global kinetic simulations of magnetotail plasma are discussed. A region of strongly nonadiabatic ion acceleration (known as the 'wall' region) exists in the near earth tail and demarcates two very different regimes of ion motion: adiabatic and quasi-adiabatic. After convection through the wall, ion distributions rapidly become isotropized and thermalized. A strong enhancement of the cross tail current occurs on the tailward side of the wall. Comparison of numerical and adiabatic pressure profiles indicates that nonadiabatic processes operating in this region may contribute significantly to a pressure balance relief in the course of quasi-steady magnetospheric convection.

Ashour-Abdalla, Maha; Zelenyi, L. M.; Bosqued, Jean-Michael; Peroomian, V.; Wang, Z.; Schriver, D.; Richard, R.

1992-01-01

211

Windfarm earthing  

Energy Technology Data Exchange (ETDEWEB)

A windfarm earthing system is normally large when compared to an earthing system typically used in a transmission or distribution substation. Typical methods used to design an earthing system of a substation may not be applicable for use on a windfarm. Any earthing system must be designed to meet a number of requirements, these include: ensuring that living beings in the vicinity are not exposed to unsafe potentials under steady state or fault conditions (lightning/switching surges and power system phase to earth faults); retain system voltages within reasonable limits under fault conditions and ensure that insulation breakdown voltages are not exceeded; provide a sufficiently low impedance to facilitate the operation of electrical protection. Some of the factors that have to be accounted for when designing an earthing system to satisfy all of the above requirements include the windfarm soil resistivity, the power system earth fault level at each wind turbine, the operating speed of the power system protection and the level of lightning protection required. A number of these issues are discussed in this paper. (UK)

Cotton, I. [UMIST, Manchester (United Kingdom). Centre for Electrical Energy

1999-07-01

212

Earth watch  

Energy Technology Data Exchange (ETDEWEB)

Over 80 LANDSAT images are presented in a spacious format in Earth Watch, an associated volume to Man on Earth by the same author, which contains only 5 plates concerned with petroleum-related activities. Each plate is accompanied by an explanatory diagram and map, and a short textual description in which the salient features of each image are interpreted, and a geographical and historical summary provided. Earth Watch contains an informative introduction to the techniques of image transmission, selection and false-color reproduction.

Sheffield, C.

1986-01-01

213

Rare earths  

International Nuclear Information System (INIS)

The conference was held from September 12 to 13, 1984 in Jetrichovice, Czechoslovakia. The participants heard 16 papers of which 4 were inputted in INIS. These papers dealt with industrial separation processes of rare earths, the use of chemical methods of separation from the concentrate of apatite and bastnesite, the effect of the relative permittivity of solvents in the elution of rare earth elements from a cation exchanger, and the determination of the content of different rare earth elements using X-ray fluorescence analysis and atomic absorption spectroscopy. (E.S.)

1984-09-12

214

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

215

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

1989-04-26

216

ITER - Earthing  

Energy Technology Data Exchange (ETDEWEB)

Earthing of electrical installations is mainly governed by safety rules. Electromagnetic compatibility also deals with earthing, among other circuit characteristics. Tokamaks are large-scale electrical installations that are known to generate large and low frequency magnetic fields as well as large and high frequency electric fields. Four European Tokamak installations have been investigated, from the earthing point of view, to identify appropriate techniques to earth the electrical equipment and to provide the lowest possible electromagnetic interference with the measurement circuits. But none of these existing installations looks like ITER, not even remotely. The plasma current range, the superconducting coils, the thick and continuous vacuum vessel, the cryostat, the very high voltage of its neutral beam injectors, the available amount of auxiliary heating power, the sensitivity of its magnetic measurements required for long pulses, the size of the site and the powerful supply grid all affect the plant earthing. Based on these investigations and the ITER specificities, a layout of the ITER site electrical supply grid and of the related earthing grid is proposed. Basic rules to reduce the electromagnetic noise at its sources and to improve the measurement immunity are also suggested.

Perez, Albert, E-mail: albert.perez@epfl.ch [Ecole Polytechnique Federale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas (CRPP), Association EURATOM-Confederation Suisse, CH-1015 Lausanne (Switzerland); Fasel, Damien; Lister, Jonathan; Marletaz, Blaise; Marmillod, Philippe; Siravo, Ugo [Ecole Polytechnique Federale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas (CRPP), Association EURATOM-Confederation Suisse, CH-1015 Lausanne (Switzerland)

2011-10-15

217

ITER - Earthing  

International Nuclear Information System (INIS)

Earthing of electrical installations is mainly governed by safety rules. Electromagnetic compatibility also deals with earthing, among other circuit characteristics. Tokamaks are large-scale electrical installations that are known to generate large and low frequency magnetic fields as well as large and high frequency electric fields. Four European Tokamak installations have been investigated, from the earthing point of view, to identify appropriate techniques to earth the electrical equipment and to provide the lowest possible electromagnetic interference with the measurement circuits. But none of these existing installations looks like ITER, not even remotely. The plasma current range, the superconducting coils, the thick and continuous vacuum vessel, the cryostat, the very high voltage of its neutral beam injectors, the available amount of auxiliary heating power, the sensitivity of its magnetic measurements required for long pulses, the size of the site and the powerful supply grid all affect the plant earthing. Based on these investigations and the ITER specificities, a layout of the ITER site electrical supply grid and of the related earthing grid is proposed. Basic rules to reduce the electromagnetic noise at its sources and to improve the measurement immunity are also suggested.

2011-10-01

218

Matchings in balanced hypergraphs  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We give a new proof of K\\"onig's theorem and generalize the Gallai-Edmonds decomposition to balanced hypergraphs in two different ways. Based on our decompositions we give two new characterizations of balanced hypergraphs and show some properties of matchings and vertex cover in balanced hypergraphs.

Scheidweiler, Robert; Triesch, Eberhard

2009-01-01

219

Get the Balance Right.  

Science.gov (United States)

Today work goes on 24 hours a day, 7 days a week, and is about acceleration and access. Workers need balance more than ever. In fact, recent college graduates value work/life balance as their key factor in selecting employers. This paper, written for career counselors, defines balance as encompassing emotional, spiritual, physical, and…

Haddock, Rebecca Jaurigue

220

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

 
 
 
 
221

DYMAC digital electronic balance  

International Nuclear Information System (INIS)

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

222

Ce{sub 2}B{sub 8}O{sub 15}. High-pressure synthesis and crystal structure determination of a rare-earth polyborate exhibiting a new 'Fundamental Building Block'  

Energy Technology Data Exchange (ETDEWEB)

The new cerium polyborate Ce{sub 2}B{sub 8}O{sub 15} was synthesized under high-pressure/high-temperature conditions of 6 GPa and 1050 C in a Walker-type multianvil apparatus. The single-crystal structure determination revealed that the new compound crystallizes in the space group P2/c with the lattice parameters a = 916.6(2), b = 421.0(1), c = 1248.9(3) pm, {beta} = 116.7(1) , V = 0.4303(2) nm{sup 3}, R1 = 0.0356, and wR2 = 0.0504. The crystal structure of Ce{sub 2}B{sub 8}O{sub 15} exhibits a new fundamental building block (FBB) in borate chemistry that consists of four BO{sub 4} tetrahedra and can be written as 4{open_square}: [{Phi}] left angle 3{open_square} right angle vertical stroke {open_square} vertical stroke. These FBB are interconnected via common corners, forming a complex threedimensional network that contains the Ce{sup 3+} cations. Ce{sub 2}B{sub 8}O{sub 15} represents the most boron rich rare-earth borate synthesized under high-pressure/high-temperature conditions so far. We report about the synthetic conditions, structural details, thermal behaviour, and the IR/Raman spectra of Ce{sub 2}B{sub 8}O{sub 15}. (orig.)

Glaetzle, Matthias; Heymann, Gunter; Huppertz, Hubert [Innsbruck Univ. (Austria). Inst. fuer Allgemeine, Anorganische und Theoretische Chemie

2013-10-01

223

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

224

Generation of the substorm-fac by slow mode disturbances in the near Earth plasma sheet  

International Nuclear Information System (INIS)

Complete text of publication follows. The magnetospheric substorm is the fundamental but unsolved problem in the solar-terrestrial physics. In our previous studies, by using the GEOTAIL/MGF, LEP, and EPIC data, we have presented the fundamental structure of convection in the near-earth magnetotail and suggested a scenario for the behavior of near-earth plasma sheet during substorms. Observational facts obtained from these studies are summarized as follows: (1) The stress balance is primarily achieved by -grad P and J x B. This basic condition remains unchanged even in the magnetotail disturbances. (2) The diamagnetic property pertains to variation of all time scales. (3) In relatively near-earth magnetotail, -grad P is intensified for a few tens of minutes prior to the onset of magnetotail disturbances. The enhancement subsides in accordance with the development of disturbances. As for the interval of substorms, (i) during the growth phase, plasma pressure is intensified in the near-earth plasma sheet and additional earthward pressure gradient is superimposed to the background gradient. The plasma pressure peak is formed in the region less than the radial distance of 8 RE. (ii) After the onset, enhanced pressure gradient is reduced in accordance with the development of slow mode disturbances. Consequentially, the plasma stress and the Maxwell stress are reduced in the near-earth tail where they have been intensified during the growth phase. From these observational facts, it is suggested that the slow mode is the primary process as the non-Alfvenic (non-convective) motion in the earth's magnetotail. The role of slow mode motion is to resolve the pressure gradient and magnetic tension along the background magnetic field. The slow mode disturbance is crucial for the redistribution of plasma fluid along the magnetic field and the reconfiguration of magnetic field. The excitation of the substorm-FAC must be explained by the energy and stress balance consistent with the above facts. In this paper, we refine the data analysis and examined in detail some substorm events. We will show the obtained results and propose its implication for the excitation of substorm-FAC.

2009-08-23

225

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

226

Earth anchors  

Energy Technology Data Exchange (ETDEWEB)

An earth anchor comprising an insertable shank portion and a locking means for securing the anchor in an earth formation has one or more locking members captively associated with the insertable shank portion, those locking members being either tiltable or rotatable relative to the shank. The insertable portion is inserted into a borehole in an earth formation and, upon tensioning of the shank, the locking members wedgingly engage with the wall of the borehole to anchor the device within the borehole. The device has particular application as a means for suspending utility conduits and the like against the wall or floor of an undergound excavation, even in weak materials such as coal. 18 figs.

Tucker, M.C.

1988-04-05

227

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

2012-12-01

228

Digital Earth - A sustainable Earth  

Science.gov (United States)

All life, particularly human, cannot be sustainable, unless complimented with shelter, poverty reduction, provision of basic infrastructure and services, equal opportunities and social justice. Yet, in the context of cities, it is believed that they can accommodate more and more people, endlessly, regardless to their carrying capacity and increasing ecological footprint. The 'inclusion', for bringing more and more people in the purview of development is often limited to social and economic inclusion rather than spatial and ecological inclusion. Economic investment decisions are also not always supported with spatial planning decisions. Most planning for a sustainable Earth, be at a level of rural settlement, city, region, national or Global, fail on the capacity and capability fronts. In India, for example, out of some 8,000 towns and cities, Master Plans exist for only about 1,800. A chapter on sustainability or environment is neither statutorily compulsory nor a norm for these Master Plans. Geospatial technologies including Remote Sensing, GIS, Indian National Spatial Data Infrastructure (NSDI), Indian National Urban Information Systems (NUIS), Indian Environmental Information System (ENVIS), and Indian National GIS (NGIS), etc. have potential to map, analyse, visualize and take sustainable developmental decisions based on participatory social, economic and social inclusion. Sustainable Earth, at all scales, is a logical and natural outcome of a digitally mapped, conceived and planned Earth. Digital Earth, in fact, itself offers a platform to dovetail the ecological, social and economic considerations in transforming it into a sustainable Earth.

Mahavir

2014-02-01

229

Melting of iron-silicon alloy up to the core-mantle boundary pressure: implications to the thermal structure of the Earth's core  

Science.gov (United States)

The melting temperature of Fe-18 wt% Si alloy was determined up to 119 GPa based on a change of laser heating efficiency and the texture of the recovered samples in the laser-heated diamond anvil cell experiments. We have also investigated the subsolidus phase relations of Fe-18 wt% Si alloy by the in-situ X-ray diffraction method and confirmed that the bcc phase is stable at least up to 57 GPa and high temperature. The melting curve of the alloy was fitted by the Simon’s equation, P(GPa)/ a = ( T m(K)/ T 0) c , with parameters, T 0 = 1,473 K, a = 3.5 ± 1.1 GPa, and c = 4.5 ± 0.4. The melting temperature of bcc Fe-18 wt% Si alloy is comparable with that of pure iron in the pressure range of this work. The melting temperature of Fe-18 wt% Si alloy is estimated to be 3,300-3,500 K at 135 GPa, and 4,000-4,200 K at around 330 GPa, which may provide the lower bound of the temperatures at the core-mantle boundary and the inner core-outer core boundary if the light element in the core is silicon.

Asanuma, Hidetoshi; Ohtani, Eiji; Sakai, Takeshi; Terasaki, Hidenori; Kamada, Seiji; Kondo, Tadashi; Kikegawa, Takumi

2010-06-01

230

Water and sodium balance in space.  

Science.gov (United States)

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. PMID:11532707

Drummer, C; Norsk, P; Heer, M

2001-09-01

231

A climatic thermostat making Earth habitable  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The mean surface temperature on Earth and other planets with atmospheres is determined by the radiative balance between the non-reflected incoming solar radiation and the outgoing long-wave black-body radiation from the atmosphere. The surface temperature is higher than the black-body temperature due to the greenhouse warming. Balancing the ice-albedo cooling and the greenhouse warming gives rise to two stable climate states. A cold climate state with a completelyice-covered...

Ditlevsen, Peter D.

2005-01-01

232

Medical Devices Assess, Treat Balance Disorders  

Science.gov (United States)

You may have heard the phrase as difficult as walking and chewing gum as a joking way of referring to something that is not difficult at all. Just walking, however, is not all that simple physiologically speaking. Even standing upright is an undertaking requiring the complex cooperation of multiple motor and sensory systems including vision, the inner ear, somatosensation (sensation from the skin), and proprioception (the sense of the body s parts in relation to each other). The compromised performance of any of these elements can lead to a balance disorder, which in some form affects nearly half of Americans at least once in their lifetimes, from the elderly, to those with neurological or vestibular (inner ear) dysfunction, to athletes with musculoskeletal injuries, to astronauts returning from space. Readjusting to Earth s gravity has a significant impact on an astronaut s ability to balance, a result of the brain switching to a different "model" for interpreting sensory input in normal gravity versus weightlessness. While acclimating, astronauts can experience headaches, motion sickness, and problems with perception. To help ease the transition and study the effects of weightlessness on the body, NASA has conducted many investigations into post-flight balance control, realizing this research can help treat patients with balance disorders on Earth as well. In the 1960s, the NASA-sponsored Man Vehicle Laboratory at the Massachusetts Institute of Technology (MIT) studied the effects of prolonged space flight on astronauts. The lab s work intrigued MIT doctoral candidate Lewis Nashner, who began conducting NASA-funded research on human movement and balance under the supervision of Dr. Larry Young in the MIT Department of Aeronautics and Astronautics. In 1982, Nashner s work resulted in a noninvasive clinical technique for assessing the cooperative systems that allow the body to balance, commonly referred to as computerized dynamic posturography (CDP). CDP employs a series of dynamic protocols to isolate and assess balance function deficiencies. The technology was based on Nashner s novel, engineering-inspired concept of balance as an adaptable collaboration between multiple sensory and motor systems. CDP proved useful not only for examining astronauts, but for anyone suffering from balance problems. Today, CDP is the standard medical tool for objectively evaluating balance control.

2009-01-01

233

Earth's magnetosphere  

International Nuclear Information System (INIS)

The following aspects of the Earth's magnetosphere were discussed: general structure, magnetic field merging and magnetospheric convection, time-varying convection and magnetospheric substorms, magnetic storms, and comparative magnetospheres. Solar flares and the magnetospheres of Mercury, Venus, Mars, Jupiter, Saturn, and Uranus were also described

1976-01-01

234

Studies of the draping and flaring angles of the Mars and Earth magnetotails  

Science.gov (United States)

Observations of the Mars tail by the spacecraft have been used to estimate the draping angle of the magnetic field within the tail and the boundary flaring angle. The boundary of the tail is defined by the sudden disappearance of the proton flux by the TAUS ion spectrometer. Solar wind measurements by the TAUS instrument are used to calculate the approximate solar wind dynamic pressure when the spacecraft is within the tail boundary. The average draping angle (Arcsin((square root of (By2 + Bz2))/BT)) is found to be 27.2 deg +/- 1.4 deg. The draping angle magnitude depends on the solar wind dynamic pressure, but is quite variable. The flaring angle of the tail boundary at X = -2.5 RM has also been calculated from the balance of pressure between the lobe of the Martian tail and the component pressures of the solar wind. The flaring angle depends strongly on the solar wind dynamic pressure, and this dependence is identical to that obtained at the Earth by Petrinec and Russell. However, the magnitude of the flaring angle at Mars X = -2.5 RM is one-half the value obtained at Earth for -22.5 RE is less than or equal to X -10 RE.

Zhang, T.-L.; Schwingenschuh, K.; Petrinec, S. M.; Russell, C. T.; Luhmann, J. G.; Rosenbauer, H.; Verigin, M. I.; Kotova, G.

1995-08-01

235

Phase transitions and equations of state of alkaline earth fluorides CaF[subscript 2], SrF[subscript 2], and BaF[subscript 2] 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 (Fm{bar 3} 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.

Dorfman, Susannah M.; Jiang, Fuming; Mao, Zhu; Kubo, Atsushi; Meng, Yue; Prakapenka, Vitali B.; Duffy, Thomas S. (Princeton); (CIW); (UC)

2010-06-14

236

Static balance and developmental coordination disorder.  

Science.gov (United States)

The development of static balance is a basic characteristic of normal motor development. Most of the developmental motor tests include a measure of static balance. Children with a developmental coordination disorder (DCD) often fail this item. Twenty-four children at risk for DCD with balance problems (DCD-BP) and 24 matched control children in the age range of 6-12 years participated in a detailed study of balance control. Additional groups of children (6-7 years, N=25; 10-11 years, n=16; with M-ABC scores >15th percentile) were selected randomly to study developmental changes in balance control in the age range of interest. Three experiments were conducted to examine developmental and clinical differences in the control of static balance. In the first, we measured the excursion of the centre of pressure (force-plate) in conditions with and without vision while standing still on one or two legs for 20 s. In the second experiment, EMGs were measured while standing on one leg. In the third experiment, in which only a subgroup of the DCD-BP and matched control children participated, a short unexpected force in the back lightly perturbed normal standing and EMG and force-plate responses were measured during balance recovery. In conditions of one-leg stance, children were not always able to maintain balance. Only epochs of stable postural control (7.5-20 s) were analysed. The results showed improvement of static balance with age, but only subtle differences between the DCD and control groups. Centre of pressure measures differed in the more difficult conditions. DCD-BP children had more difficulty standing on one leg with eyes closed. While standing on the non-preferred leg the EMGs of the DCD-BP children showed slightly more co-activation of the muscles of lower and upper leg. Perturbation of standing resulted in longer duration of recovery in the first trial in this group. Apparently DCD children learn to compensate for the perturbation within a few trials as well as control children do. The clear improvement with age shows that our measures of balance control are sensitive to detect changes. The general conclusion that may be drawn from this study is that under normal conditions static balance control is not a problem for children with DCD. Only in difficult or novel situations they seem to suffer from increased postural sway as a result of non-optimal balance control. PMID:14624832

Geuze, Reint H

2003-11-01

237

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

238

Technique for Enhanced Rare Earth Separation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

2000-01-01

239

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

240

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

 
 
 
 
241

Impact Earth  

Science.gov (United States)

This 24 minute planetarium show teaches about meteors, meteorites, asteroids, and comets. The show was created for fulldome theaters, but is also available on DVD to be shown in flat version for TVs and computer monitors, and can be freely viewed online. It shows the effects of the Chixulub and Tungusta events, plus the Pallasite impact that resulted in the Brenham meteorite fall, and describes ways that asteroid hunters seek new objects in the solar system, and how ground penetrating radar is used to find meteorites that have survived to the Earth's surface. Narrated by astronaut Tom Jones, it also discusses ways that humans might try to deflect an asteroid or comet that is on a collision course with Earth. The show was created for informal science venues (digital planetariums); it is also useful as supplemental material for middle school science. Impact Earth is available for free if presented directly from the Space Update site (widescreen or fisheye views linked from YouTube). Otherwise, a DVD of the show can be purchased for $10.

242

Earth Gauge  

Science.gov (United States)

Earth Gauge is a free environmental information service for broadcast meteorologists in major U.S. media markets, based on the 3-5 day forecast. The service is designed to make it easy to talk about the links between weather and the environment on-air with simple "factoids" and viewer action tips. Teachers or students can browse an index of weather conditions, environmental impacts, and viewer action tips for many locations, organized by city, weather type, or environmental topic. There are also links to additional resources, including fact sheets and special features, imagery, video clips, and others.

243

Properties of Balanced Permutations  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper takes a close look at balanced permutations, a recently developed sample reuse method with applications in bioinformatics. It turns out that balanced permutation reference distributions do not have the correct null behavior, which can be traced to their lack of a group structure. We find that they can give p-values that are too permissive to varying degrees. In particular the observed test statistic can be larger than that of all B balanced permutations of a data set with a probabi...

Southworth, Lucinda K.; Kim, Stuart K.; Owen, Art B.

2009-01-01

244

Social Balance Explanation  

Science.gov (United States)

A triad of attitudinal relationships is considered balanced if all three relationships are positive, or if one is positive and two are negative. Balance theory has been extended to apply to larger interpersonal groups (Situngkir & Khanafiah, 2004), perceptions of groups such as the US Supreme Court (Pilialoha & Brewer, 2006), matchmaking (Chapdelaine, Kenny, & LaFontana, 1994), the connection between voters and their political parties (Ray, 1999), bargaining (Kette, 1986), and developing a comprehensive theory of self-esteem, self-concept, implicit attitudes and stereotyping (Greenwald, Banaji, Rudman, Farnham, Nosek, & Mellot, 2002). This page describes a study that can be used to illustrate balance theory.

245

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

246

Balance of Power  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper argues that the efficiency distribution of players in a game determines how aggressively these players interact.We formalize the idea of balance of power: players fight very inefficient players but play softly versus equally (or more) efficient players.This theory of conduct predicts that entry by new firms leads to a less aggressive outcome if it creates a balance of power. A balance of power is created if more players get technologies that are close to the most efficient technolo...

Boone, J.

2004-01-01

247

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

248

Rotating Balances Used for Fluid Pump Testing  

Science.gov (United States)

Marshall Space Flight Center has developed and demonstrated two direct read force and moment balances for sensing and resolving the hydrodynamic loads on rotating fluid machinery. These rotating balances consist of a series of stainless steel flexures instrumented with semiconductor type, unidirectional strain gauges arranged into six bridges, then sealed and waterproofed, for use fully submerged in degassed water at rotational speeds up to six thousand revolutions per minute. The balances are used to measure the forces and moments due to the onset and presence of cavitation or other hydrodynamic phenomena on subscale replicas of rocket engine turbomachinery, principally axial pumps (inducers) designed specifically to operate in a cavitating environment. The balances are inserted into the drive assembly with power to and signal from the sensors routed through the drive shaft and out through an air-cooled twenty-channel slip ring. High frequency data - balance forces and moments as well as extensive, flush-mounted pressures around the rotating component periphery - are acquired via a high-speed analog to digital data acquisition system while the test rig conditions are varied continuously. The data acquisition and correction process is described, including the in-situ verifications that are performed to quantify and correct for known system effects such as mechanical imbalance, "added mass," buoyancy, mechanical resonance, and electrical bias. Examples of four types of cavitation oscillations for two typical inducers are described in the laboratory (pressure) and rotating (force) frames: 1) attached, symmetric cavitation, 2) rotating cavitation, 3) attached, asymmetric cavitation, and 4) cavitation surge. Rotating and asymmetric cavitation generate a corresponding unbalanced radial force on the rotating assembly while cavitation surge generates an axial force. Attached, symmetric cavitation induces no measurable force. The frequency of the forces can be determined a priori from the pressure environment while the magnitude of the hydrodynamic force is proportional to the pressure unsteadiness.

Skelley, Stephen; Mulder, Andrew

2014-01-01

249

Fluid and Electrolyte Balance  

Science.gov (United States)

Electrolytes are minerals in your body that have an electric charge. They are in your blood, urine and body fluids. Maintaining the right balance of electrolytes helps your body's blood chemistry, muscle action and ...

250

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.)

251

Balanced-bellows spirometer  

Science.gov (United States)

Compact balanced-bellows dry type spirometer was designed to be insensitive to acceleration fields along any or all coordinate axes. It provides true indication of respiratory action of test subject without need for calibration in acceleration fields.

Holden, G. G.; Smith, J. R., Jr.

1972-01-01

252

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

253

Older Adults and Balance Problems  

Medline Plus

Full Text Available ... with each other -- kind of organized by the brain -- to help us maintain our balance, or, another ... balance nerve then sends the stimulation to the brain centers for balance. Another leg of the stool ...

254

A climatic thermostat making Earth habitable  

CERN Multimedia

The mean surface temperature on Earth and other planets with atmospheres is determined by the radiative balance between the non-reflected incoming solar radiation and the outgoing long-wave black-body radiation from the atmosphere. The surface temperature is higher than the black-body temperature due to the greenhouse warming. Balancing the ice-albedo cooling and the greenhouse warming gives rise to two stable climate states. A cold climate state with a completelyice-covered planet, called Snowball Earth, and a warm state similar to our present climate where greenhouse warming prevents the total glacition. The warm state has dominated Earth in most of its geological history despite a 30 % fainter young Sun. The warming could have been controlled by a greenhouse thermostat operating by temperature control of the weathering process depleting the atmosphere from $CO_2$. This temperature control has permitted life to evolve as early as the end of the heavy bombartment 4 billion years ago.

Ditlevsen, P D

2005-01-01

255

Energy Balance and Obesity  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper describes the interplay among energy intake, energy expenditure and body energy stores and illustrates how an understanding of energy balance can help develop strategies to reduce obesity. First, reducing obesity will require modifying both energy intake and energy expenditure and not simply focusing on either alone. Food restriction alone will not be effective in reducing obesity if human physiology is biased toward achieving energy balance at a high energy flux (i.e. at a high le...

2012-01-01

256

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 constitutional rules in 71 countries that reflect these provisions. We find strong support for the proposition that both judicial independence and constitutional review are associated with greater freedom....

La Porta, Rafael; Lopez-de-silanes, Florencio; Pop-eleches, Cristian; Shleifer, Andrei

2004-01-01

257

Workhours and worklife balance  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2008-01-01

258

The Effects of Virtual Reality-based Balance Training on Balance of the Elderly.  

Science.gov (United States)

[Purpose] The objective of this study was to determine the effects of virtual reality-based balance training on balance of the elderly. [Methods] The subjects were 32 healthy elderly people aged between 65 and 80, who were divided into a VR (virtual reality) training group (n=17) and a control group (n=15). The VR training group engaged in a 30-minute exercise session using Wii Fit three times a week for eight weeks, while the control group received no intervention. The balance of the two groups was measured before and after the intervention. [Results] According to the Romberg Test conducted to examine the effects of the training on balance, both the area covered by the body's center of pressure movement, and movement distances per unit area of the body's center of pressure envelope significantly decreased in the VR training group. Moreover, the two groups showed significant differences in balance. [Conclusion] Virtual reality training is effective at improving the balance of the healthy elderly. Thus, virtual reality training can be proposed as a form of fall prevention exercise for the elderly. PMID:24764645

Cho, Gyeong Hee; Hwangbo, Gak; Shin, Hyung Soo

2014-04-01

259

Anisotropic Alfven-ballooning modes in Earth`s magnetosphere  

Energy Technology Data Exchange (ETDEWEB)

The authors have carried out a theoretical analysis of the stability and parallel structure of coupled shear Alfven and slow magnetosonic waves in Earth`s inner magnetosphere (i.e., at equatorial distances between about five and ten Earth radii) including effects of finite anisotropic plasma pressure. Multiscale perturbation analysis of the anisotropic Grad-Shafranov equation yields an approximate self-consistent magnetohydrodynamic (MHD) equilibrium. This MHD equilibrium is used in the numerical solution of a set of eigenmode equations which describe the field line eigenfrequency, linear stability, and parallel eigenmode structure. The authors call these modes anisotropic Alfven-ballooning modes. The main results are: (1) The field line eigenfrequency can be significantly lowered by finite pressure effects. (2) The parallel mode structure of the transverse wave components in fairly insensitive to changes in the plasma pressure, but the compressional magnetic component can become highly peaked near the magnetic equator as a result of increased pressure, especially when P{perpendicular}>P{parallel} (here P{perpendicular} and P{parallel} are the perpendicular and parallel plasma pressure). (3) For the isotropic (P{parallel}=P{perpendicular}=P) case ballooning instability can occur when the ratio of the plasma pressure to the magnetic pressure exceeds a critical value {beta}{sub 0}{sup B}{approx} 3.5 at the equator. (4) Compared to the isotropic case the critical beta value is lowered by anisotropy. (5) The authors use a {beta}-{delta} stability diagram to display the regions of instability with respect to the equatorial values of the parameters {beta} and {delta}, where {beta} = (1/3)({beta}{parallel}+2{beta}{perpendicular}) is an average beta value and {delta}=1-P{parallel}/P{perpendicular} is a measure of the plasma anisotropy. The diagram is divided into regions corresponding to the firehose, mirror and ballooning instabilities. 31 refs., 8 figs.

Chan, A.A. [Rice Univ., Houston, TX (United States); Xia, M. [Peking Univ., Beijing (China); Chen, L. [Univ. of California, Irving, CA (United States)

1994-09-01

260

Improve SSME power balance model  

Science.gov (United States)

Effort was dedicated to development and testing of a formal strategy for reconciling uncertain test data with physically limited computational prediction. Specific weaknesses in the logical structure of the current Power Balance Model (PBM) version are described with emphasis given to the main routing subroutines BAL and DATRED. Selected results from a variational analysis of PBM predictions are compared to Technology Test Bed (TTB) variational study results to assess PBM predictive capability. The motivation for systematic integration of uncertain test data with computational predictions based on limited physical models is provided. The theoretical foundation for the reconciliation strategy developed in this effort is presented, and results of a reconciliation analysis of the Space Shuttle Main Engine (SSME) high pressure fuel side turbopump subsystem are examined.

Karr, Gerald R.

1992-01-01

 
 
 
 
261

Diasporic Trauma in Unaccustomed Earth  

Directory of Open Access Journals (Sweden)

Full Text Available Jhumpa Lahiri is a famous Indian American author whose works consistently deal with the themes like diaspora, dislocation and belonging. She explores the trauma of diaspora in her third book Unaccustomed Earth in which the characters suffer from the loss of a traditional culture, death of a family member, the sense of rootlessness, double consciousness and generation conflicts. This paper argues that only by renegotiating the relationship between the past and present, keeping the balance between memories and forgetting, can characters in the novel gradually work through their trauma and reconstruct a new identity.

Ling YUN

2014-04-01

262

Balanced articulated manipulator  

International Nuclear Information System (INIS)

The description is given of a manipulator of the type comprising a master arm and a slave arm, capable of working in a containment restricted by a wall fitted with an aperture to introduce the slave arm into the containment. According to the invention this manipulator is permanently balanced irrespective of its distortions when it is secured to the wall of the containment in which it is desired to work. The entire manipulator is also balanced when being set up and when moved outside the containment, in relation to a supporting axle. This result is achieved in a simplified manner by giving homothetic shapes to the various component parts of the slave and master arms, the master arm having at least one balancing weight

1976-01-01

263

The Lifeworld Earth and a Modelled Earth  

Science.gov (United States)

The goal of this paper is to study the question of whether a phenomenological view of the Earth could be empirically endorsed. The phenomenological way of thinking considers the Earth as a material entity, but not as an object as viewed in science. In the learning science tradition, tracking the process of the conceptual change of the shape of the Earth, science's view of the Earth as an object—a celestial body—has been applied. I reanalysed data published in Vosniadou and Brewer's (Cognit psychol 24:535-585, 1992) seminal paper. According to my reanalysis of their interview material, it is plausible to conclude that the Earth as an infinite surface is the way to experience the Earth. Further, the `dual Earth model' is the first model of the Earth as an object. I conclude that experiences in the lifeworld need to be taken into consideration more seriously in science education research.

Juuti, Kalle

2013-07-01

264

Finding Your Balance  

CERN Document Server

Balance isn't an issue of time, but an issue of choice. It's about living your values by aligning your behavior with what you believe is really important. Aligning your behavior with your values is much like any other developmental experience; the basic process involves assessment, challenge, and support. You need to determine where you are, define where you want to go, and then put into place the tools you need to get there.Balance is about more than how you spend your time. It's about how you live your life. It's about recognizing that you have control over the choices you make and aligning

(CCL), Center for Creative Leadership; Patterson, Gordon

2011-01-01

265

Current balancing for battery  

Energy Technology Data Exchange (ETDEWEB)

A battery plant is described which features magnetic circuit means for balancing the electrical current flow through a pluraliircuitbattery strings which are connected electrically in parallel. The magnetic circuit means is associated with the battery strings such that the conductors carrying the electrical current flow through each of the battery strings pass through the magnetic circuit means in directions which cause the electromagnetic fields of at least one predetermined pair of the conductors to oppose each other. In an alternative embodiment, a low voltage converter is associated with each of the battery strings for balancing the electrical current flow through the battery strings.

Galloway, J. H.

1985-02-26

266

Seasonal contributions of precipitation to recharge: Completely different estimates from water budget and stable isotope balance  

International Nuclear Information System (INIS)

The seasonal recharge into a karstified aquifer system of the Franconian Alb, southern Germany, was determined for 1995 and 1996 by balancing stable isotope composition of precipitation with that of ground water and by water balancing applying the empirical formula of Haude which introduces climatic parameters like mean daily temperature, humidity, and precipitation as well as the natural features of earth's surface

1999-12-01

267

Center of pressure excursion as a measure of balance performance in patients with non-specific low back pain compared to healthy controls: a systematic review of the literature  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Over the past 20 years, the center of pressure (COP) has been commonly used as an index of postural stability in standing. While many studies investigated COP excursions in low back pain patients and healthy individuals, no comprehensive analysis of the reported differences in postural sway pattern exists. Six online databases were systematically searched followed by a manual search of the retrieved papers. The selection criteria comprised papers comparing COP measures derived from bipedal s...

Ruhe, Alexander; Fejer, Rene?; Walker, Bruce

2011-01-01

268

National energy balance - 1978  

International Nuclear Information System (INIS)

The national energy balance of 1978 shows some modifications in relation to the last year. New tables were included aiming to show the brazilian energy situation, such as the hydraulic potential and the non-renewable energy resources. (E.G.)

1978-01-01

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

National energy balance - 1977  

International Nuclear Information System (INIS)

The national energy balance of the 1976 shows several modifications in relation to the last year. The historical serie is based in more confiable information, from several energy companies. The most greater modifications are on energy source of hard control, such as lignite and charcoal for non-siderurgic uses. (E.G.)

1977-01-01

271

National Energy Balance - 1981  

International Nuclear Information System (INIS)

The National Energy Balance - 1981, shows a new metodology and information in level of several economic sectors, as well as a separation of primary and secondary energy sources, its energy fluxes, i.e. production, imports, exports, consumption, etc...(E.G.)

1981-01-01

272

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.

Alexander I. Bogoyavlenskii

2010-10-01

273

The Earth: Present Scenario  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Nishad Gopal Deshpande

2009-01-01

274

Using balance program for energy balance analysis  

International Nuclear Information System (INIS)

Belong with development of the economy, the energy consumption will be increased very high in the future. Vietnam has a broad range of mineral resources. There is considerable energy potential on form of coal, oil and gas, hydropower and fuel wood, Recently, Vietnam is an exporter of energy. But in next two decades, the energy sources will be enough to meet requirement? The model BALANCE was used to solve energy planning problem. The objective of this model is analyzing energy system and built an energy development strategy in long term. After using model, the results are: total coal consumption will be 17.440 Mtoe in 2020 and 32 Mtoe in 2030. the biggest coal consumer is electricity sector. Total oil production consumption will be more than 30 Mtoe in 2020 and more than 50 Mtoe in 2030. If we have 4 refinery factories from now to 2030, total oil products import will be 11 Mtoe in 2020 and 25 Mtoe in 2030. The amount of gas supply in 2030 will be 20 billions m3 (18 Mtoe). Vietnam needs to import 8.3 Mtoe more, Vietnam will become an energy importer in next 15 years. In previous years, the economy of Vietnam was mainly based on agricultural production. But Vietnam is moving rapidly from an agricultural to an industrial economy. Belong with the development of the economy, energy consumption increases very fast. So which energy sources should be used first and when it will be use...are questions need to be answered. Vietnam has a broad range of mineral resources. There is considerable energy potential on form of coal, oil and gas, hydropower and fuel wood. Recently, Vietnam is energy exporter, but in near future Vietnam has enough energy to meet demand or we need to import from outside? It should be studied carefully to answer. (author)

2005-10-01

275

A reactivity balance meter  

International Nuclear Information System (INIS)

A research and development programme is currently being undertaken on the Rapsodie and Phenix reactors with the immediate aim of developing an on-line reactivity balance meter for Rapsodie. The principle of this system is to compare in real time the actual reactivity of the core, derived from the power trace by inversion of the point reactor kinetics equations, with a theoretical reactivity (model). The model takes into account rod effects and the effects of ageing of the fuel (burnup) and also feedback effects associated with reactor power, core gradient at constant power, and inlet temperature. The thermal effects are linked with the relative core-rod positioning (differential effects); certain coefficients thus depend on rod worth and these are distributed over a certain number of time constants. The balance meter is therefore conceived as a transfer module between the four inputs (height of the rods, reactor power, inlet temperature and flow rate of the primary sodium) and one output - the theoretical reactivity. Several series of experiments were performed on Rapsodie for the purpose of optimizing the parameters of the model. Each of these comprised a sequence of four simple transients between two stable states. The results obtained enable it to be shown that the reactivity balance is, on the whole, better than +-5 mN for dynamic behaviour over a period of about an hour. The mathematical model thus developed is applied to different modes of operation in Rapsodie, including power rise and composite transients. In these cases, in consequence of the wider dynamic range, the reactivity balance is of the order of +-10 mN

1979-09-28

276

Materials balance evaluation  

International Nuclear Information System (INIS)

The results of a physical inventory at a reference bulk materials handling facility (described in the appendix) are evaluated and the materials balance and the material unaccounted for (MUF) obtained. The uncertainty associated with MUF and its importance are explained. The procedures needed to determine whether the MUF indicates a real loss of greater than a given magnitude has occurred, or whether it is more reasonable to conclude that no loss has occurred, are described. 5 refs., 3 figs., 10 tabs

1986-06-09

277

Analysis of Balancing Markets  

Digital Repository Infrastructure Vision for European Research (DRIVER)

During the 20th century, most countries had their electricity production, transport and distribution organised as vertically integrated monopoly. Since the 90s more and more countries, especially in Europe, have replaced their state monopoly by an open market to manage their electrical power system. In order to settle a deregulated market of electricity, countries must adopt new methods and rules for trading electricity, planning production and managing the balance between electricity product...

Kiener, Elsa

2006-01-01

278

National energy balance - 1976  

International Nuclear Information System (INIS)

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 used for non-energy purposes were excluded. The energy production and consumption for the next ten years were forecasted, considering the actual brazilian energy policy. (E.G.)

279

Balance-bot  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Research on inverted pendulum has gained momentum over the last decade on a number of robotic laboratories over the world; due to its unstable proprieties is a good example for control engineers to verify a control theory. To verify that the pendulum can balance we can make some simulations using a closed-loop controller method such as the linear quadratic regulator or the proportional–integral–derivative method. Also the idea of robotic teleoperation is gaining ground. Con...

Abreu, Victor Vicente

2009-01-01

280

Older Adults and Balance Problems  

Medline Plus

Full Text Available ... can have a serious impact on an older person's life. In fact, balance problems are one reason ... in space. Narrator: Some of the symptoms a person with a balance disorder might have are vertigo -- ...

 
 
 
 
281

Balancing mechanism status: May 2009  

International Nuclear Information System (INIS)

RTE ensures the real-time balance between production and consumption and deals with congestion on the French electricity system. The Balancing Mechanism assists in the accomplishment of this task. As in many countries, and after extensive dialogue with representatives from the market's various players, RTE proposes a Balancing Mechanism in the form of a permanent and transparent system of calls for tender. The system is open to everyone and provides a real-time reserve of power that can be used for balancing either upward or downward. RTE takes advantage of these offers according to economic precedence, taking into account the system's operating conditions. It pays for them at the offer price. There are two types of offer: - Upward offer: increase in production, decrease in consumption, imports, - Downward offer: decrease in production, increase in consumption, exports. For a Balancing Entity, an offer systematically consists of: a balancing direction (upward/downward), a time period, a price that may vary according to six time slots. RTE publishes each month a Balancing Mechanism Report. which includes the following information: - energy volumes activated to ensure the balance of the system and to resolve congestion; - minimum and maximum prices of offers activated to balance the system; - daily trends calculated according to the predominant value of the overall upward or downward trend; - balancing shares by technology (nuclear, thermal, hydraulic); - characteristics of the five most activated balancing entities; - balances/imbalances accounts and production/consumption overcharge; - congestion curbing costs on the French electricity system; - energy volumes activated to ensure the balance of the system according to contracts between RTE and other Balance Responsible entities (UK, Belgium, Italy, Germany, Switzerland); - reliability of the provisional data supplied by RTE about the balancing trend; - availability of RTE's information services (planning, balancing mechanism, block exchange notification, market indicators). This report presents the above information for May 2009. (J.S.)

2009-01-01

282

Rare earth element systematics in hydrothermal fluids  

Energy Technology Data Exchange (ETDEWEB)

Rare earth element concentrations have been measured in hydrothermal solutions from geothermal fields in Italy, Dominica, Valles Caldera, Salton Sea and the Mid-Atlantic Ridge. The measured abundances show that hydrothermal activity is not expected to affect the REE balance of either continental or oceanic rocks. The REE enrichment of the solutions increases when the pH decreases. High-temperature solutions (> 230{degree}C) percolating through different rock types may show similar REE patterns.

Michard, A. (Centre de Recherches Petrographiques et Geochimiques, Vandoeuvre-les-Nancy (France))

1989-03-01

283

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

2011-07-01

284

Slackline training for balance and strength promotion.  

Science.gov (United States)

The prevalence of sustaining a sport injury is high in adults. Deficits in postural control/muscle strength represent important injury-risk factors. Thus, the purpose of this study was to investigate the impact of a specific type of balance training, i.?e. slackline training, followed by detraining on balance and strength performance. Twenty-seven adults participated in this study and were assigned to an intervention (age 22.8±3.3 yrs) or a control group (age 23.9±4.4 yrs). The intervention group participated in 4 weeks of slackline training on nylon webbings. Detraining lasted 4 weeks. Tests included the measurement of (A) total centre of pressure displacements during one-legged standing on a balance platform and during the compensation of a perturbation impulse, (B) maximal torque and rate of force development (RFD) of the plantar flexors on an isokinetic device, and (C) jumping height on a force platform. After training, no significant interaction effects were observed for variables of static/dynamic postural control, maximal torque, and jumping height. Training-induced improvements were found for RFD. After the withdrawal of the training stimulus, RFD slightly decreased. Given that the promotion of balance and strength is important for injury prevention, changes in RFD only might not be sufficient to produce an injury-preventive effect. PMID:20677124

Granacher, U; Iten, N; Roth, R; Gollhofer, A

2010-10-01

285

Application of Pascal Principle in Earth Science  

Science.gov (United States)

The Pascal experiment is interpreted and the chamber is roughly defined. Pascal experiment in relation to Pascal principle compared with a chamber in the earth crust. It is conclude that: 1: The pressure (P) inside the Pascal's cylinder is the combination of two pressure; the external pressure (P1) and the hydraulic pressure (P2). Pc=P1+P2 The direction of the force is from top to bottom. In the case of the chamber the pressure is Pch=P1-P2 and its positive direction is regarded to be from bottom to top. P1 is the external pressure, and is the maximum pressure applied to chamber .The external pressure creates a constant internal pressure throughout the chamber .The magnitude of the constant pressure is based on the litho static pressure of the bottom of the chamber; because it is the maximum pressure that the chamber is connected. P1=?1gH+?2gh Where H is the overburden thickness, h is the highness of the chamber, ?1 is the density of the overburden and ?2 is density of country rock. The hydrostatic pressure within the chamber is P2=?3gh. Also ?3 is the density of the chamber. So the pressure inside the chamber would be: Pch=P1-P2 then Pch=?1gH+(?2-?3)gh. The equation above means that, the chamber pressure equals to the overburden pressure plus Archimedes pressure. 2: The word squeezing which is a vulgar word has an important physical meaning that is ((Pascal principle driving movement)).In another word, almost all movements, related to chambers, within the earth are a squeezing event which's, driving force is the steady constant pressure mentioned above. Any change in this pressure depends on the rupturing of the chamber and the behavior of the movement of the chamber matter. 3: If we provide a safety valve on piston of the Pascal's cylinder and increase the load we see the safety valve bursts and the matter inside the cylinder squeeze out .The pressure is from top to bottom but the movement is from bottom to top. The direction of force has changed 180° degree. This is Pascal's miracle and displays the all movements that pierce the earth surface and let the matter squeeze out.

Samimi Namin, M.

2009-12-01

286

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

287

Martian Atmospheric Pressure Static Charge Elimination Tool  

Science.gov (United States)

A Martian pressure static charge elimination tool is currently in development in the Electrostatics and Surface Physics Laboratory (ESPL) at NASA's Kennedy Space Center. In standard Earth atmosphere conditions, static charge can be neutralized from an insulating surface using air ionizers. These air ionizers generate ions through corona breakdown. The Martian atmosphere is 7 Torr of mostly carbon dioxide, which makes it inherently difficult to use similar methods as those used for standard atmosphere static elimination tools. An initial prototype has been developed to show feasibility of static charge elimination at low pressure, using corona discharge. A needle point and thin wire loop are used as the corona generating electrodes. A photo of the test apparatus is shown below. Positive and negative high voltage pulses are sent to the needle point. This creates positive and negative ions that can be used for static charge neutralization. In a preliminary test, a floating metal plate was charged to approximately 600 volts under Martian atmospheric conditions. The static elimination tool was enabled and the voltage on the metal plate dropped rapidly to -100 volts. This test data is displayed below. Optimization is necessary to improve the electrostatic balance of the static elimination tool.

Johansen, Michael R.

2014-01-01

288

Center of pressure excursion as a measure of balance performance in patients with non-specific low back pain compared to healthy controls: a systematic review of the literature.  

Science.gov (United States)

Over the past 20 years, the center of pressure (COP) has been commonly used as an index of postural stability in standing. While many studies investigated COP excursions in low back pain patients and healthy individuals, no comprehensive analysis of the reported differences in postural sway pattern exists. Six online databases were systematically searched followed by a manual search of the retrieved papers. The selection criteria comprised papers comparing COP measures derived from bipedal static task conditions on a force-plate of non-specific low back pain (NSLBP) sufferers to those of healthy controls. Sixteen papers met the inclusion criteria. Heterogeneity in study designs prevented pooling of the data so only a qualitative data analysis was conducted. The majority of the papers (14/16, 88%) concluded that NSLBP patients have increased COP mean velocity and overall excursion as compared to healthy individuals. This was statistically significant in the majority of studies (11/14, 79%). An increased sway in anteroposterior direction was also observed in NSLBP patients. Patients with NSLBP exhibit greater postural instability than healthy controls, signified by greater COP excursions and a higher mean velocity. While the decreased postural stability in NSLBP sufferers further appears to be associated with the presence of pain, it seems unrelated to the exact location and pain duration. No correlation between the pain intensity and the magnitude of COP excursions could be identified. PMID:20721676

Ruhe, Alexander; Fejer, René; Walker, Bruce

2011-03-01

289

Watt and joule balances  

Science.gov (United States)

The time is fast approaching when the SI unit of mass will cease to be based on a single material artefact and will instead be based upon the defined value of a fundamental constant—the Planck constant—h . This change requires that techniques exist both to determine the appropriate value to be assigned to the constant, and to measure mass in terms of the redefined unit. It is important to ensure that these techniques are accurate and reliable to allow full advantage to be taken of the stability and universality provided by the new definition and to guarantee the continuity of the world's mass measurements, which can affect the measurement of many other quantities such as energy and force. Up to now, efforts to provide the basis for such a redefinition of the kilogram were mainly concerned with resolving the discrepancies between individual implementations of the two principal techniques: the x-ray crystal density (XRCD) method [1] and the watt and joule balance methods which are the subject of this special issue. The first three papers report results from the NRC and NIST watt balance groups and the NIM joule balance group. The result from the NRC (formerly the NPL Mk II) watt balance is the first to be reported with a relative standard uncertainty below 2 × 10?8 and the NIST result has a relative standard uncertainty below 5 × 10?8. Both results are shown in figure 1 along with some previous results; the result from the NIM group is not shown on the plot but has a relative uncertainty of 8.9 × 10?6 and is consistent with all the results shown. The Consultative Committee for Mass and Related Quantities (CCM) in its meeting in 2013 produced a resolution [2] which set out the requirements for the number, type and quality of results intended to support the redefinition of the kilogram and required that there should be agreement between them. These results from NRC, NIST and the IAC may be considered to meet these requirements and are likely to be widely debated prior to a decision on redefinition. The CCM had already recognized that agreement was close and has set in place a process whereby redefinition can take place by 2018. The final decision will be in the hands of the Conférence Générale des Poids et Mesures (CGPM) but the results reported here should aid a positive decision. Figure 1. Figure 1. Results from recent measurements of the Planck constant. The reference for the results h 90 is derived from the conventional values of the Josephson constant K J?90 and the von Klitzing constant R K?90. The factor of ten improvement in uncertainty of the NRC watt balance result, over that achieved by the same apparatus at NPL a few years earlier, can be understood as a factor of five improvement arising from the elimination of an effect discovered at NPL that could not be eliminated before shipment to Canada and a factor of two arising from the considerable improvements made by NRC. Once the kilogram has been redefined, the watt and joule balances will complete their transitions from instruments that are primarily of interest to the electrical community for determining the SI electrical units from the mechanical units, to the principal methods by which an individual National Measurement Institute (NMI) can make an independent determination of the SI unit of mass and thereby contribute to the maintenance of national and international mass scales. This special issue gives an introduction to the diversity of techniques which are required for the operation of watt and joule balances. However it does not contain a review of existing balances; this was a deliberate decision, as a number of such review papers have been published in the past five years [3–7] and it was felt that it was not yet time for another. The first technique considered is that of gravimetry; the watt balance measures the weight Mg of a mass M , and to convert the measured weight into a mass, the value of the acceleration due to gravity g must be known, at the time of the weighing and at the centre of gravity of the mass. The paper by Liard a

Robinson, Ian A.

2014-04-01

290

Spreadsheet eases heat balance, payback calculations  

International Nuclear Information System (INIS)

This paper reports that a generalized Lotus type spreadsheet program has been developed to perform the heat balance and simple payback calculations for various turbine-generator (TG) inlet steam pressures. It can be used for potential plant expansions or new cogeneration installations. The program performs the basic heat balance calculations that are associated with turbine-generator, feedwater heating process steam requirements and desuperheating. The printout, shows the basic data and formulation used in the calculations. The turbine efficiency data used are applicable for automatic extraction turbine-generators in the 30-80 MW range. Simple payback calculations are for chemical recovery boilers and power boilers used in the pulp and paper industry. However, the program will also accommodate boilers common to other industries

1992-01-01

291

Fluids flow. Balance equations; Ecoulement des fluides. Equations de bilans  

Energy Technology Data Exchange (ETDEWEB)

Mass and heat transfers are the basic phenomena occurring in energy systems, in particular when fluid flows are involved. Thus the analysis of transfers during fluid flows is of prime importance to solve most of energy problems. Two different types of analysis are generally applied: local-type analyses and global-type analyses and both require the study of balances which is presented in this paper: 1 - balance of any parameter and balance equation; 2 - mass balance: local equation of mass conservation, integral equation of mass conservation (current tube and current thread); 3 - balance of movement momentum: forces applied to the fluid (definition, viscosity forces, stress tensor, stress on any plan); Cauchy equation, Navier-Stokes equation; integral equation of the movement momentum balance (application to a current tube and to a current thread); Bernoulli equation, stationary flow of a heavy incompressible fluid (integration of the Navier-Stokes equation along a streamline, Bernoulli equation, fluid load and pressure drops, particular case of linear trajectories); 4 - kinetic energy balance, generalized Bernoulli equation: general case, case of a heavy fluid, heavy fluid flow in the presence of a machine, heavy fluid inside a current tube with mobile machine parts, case of a current thread; 5 - energy balance, first principle: general case, heavy fluid in contact with mobile machine parts, heavy fluid running inside a current thread and threw a machine, thermal fluid flow equation. (J.S.)

Lallemand, A. [Institut National des Sciences Appliquees (INSA), 69 - Villeurbanne (France)

1999-07-01

292

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

293

Entropy of balance - some recent results  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Entropy when applied to biological signals is expected to reflect the state of the biological system. However the physiological interpretation of the entropy is not always straightforward. When should high entropy be interpreted as a healthy sign, and when as marker of deteriorating health? We address this question for the particular case of human standing balance and the Center of Pressure data. Methods We have measured and analyzed balance data of 136 participants (young, n = 45; elderly, n = 91 comprising in all 1085 trials, and calculated the Sample Entropy (SampEn for medio-lateral (M/L and anterior-posterior (A/P Center of Pressure (COP together with the Hurst self-similariy (ss exponent ? using Detrended Fluctuation Analysis (DFA. The COP was measured with a force plate in eight 30 seconds trials with eyes closed, eyes open, foam, self-perturbation and nudge conditions. Results 1 There is a significant difference in SampEn for the A/P-direction between the elderly and the younger groups Old > young. 2 For the elderly we have in general A/P > M/L. 3 For the younger group there was no significant A/P-M/L difference with the exception for the nudge trials where we had the reverse situation, A/P Eyes Open. 5 In case of the Hurst ss-exponent we have for the elderly, M/L > A/P. Conclusions These results seem to be require some modifications of the more or less established attention-constraint interpretation of entropy. This holds that higher entropy correlates with a more automatic and a less constrained mode of balance control, and that a higher entropy reflects, in this sense, a more efficient balancing.

Laxåback Gerd

2010-07-01

294

Balanced Interval Coloring  

CERN Document Server

We consider the discrepancy problem of coloring $n$ intervals with $k$ colors such that at each point on the line, the maximal difference between the number of intervals of any two colors is minimal. Somewhat surprisingly, a coloring with maximal difference at most one always exists. Furthermore, we give an algorithm with running time $O(n \\log n + kn \\log k)$ for its construction. This is in particular interesting because many known results for discrepancy problems are non-constructive. This problem naturally models a load balancing scenario, where $n$ tasks with given start- and endtimes have to be distributed among $k$ servers. Our results imply that this can be done ideally balanced. When generalizing to $d$-dimensional boxes (instead of intervals), a solution with difference at most one is not always possible. We show that for any $d \\ge 2$ and any $k \\ge 2$ it is NP-complete to decide if such a solution exists, which implies also NP-hardness of the respective minimization problem. In an online scenario,...

Antoniadis, Antonios; Lenzner, Pascal; Moldenhauer, Carsten; Souza, Alexander

2010-01-01

295

Earth Science Programme  

...HomeSoilLand QualityLandscapeNatural Heritage Grant ProgrammeEarth ScienceGeology of Northern...Digital DatasetsStrategic Environmental Assessment (SEA)Earth Science ProgrammeLast updated: 27 March 2009Introduction...

296

ITER-Earthing  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Earthing of electrical installations is mainly governed by safety rules. Electromagnetic compatibility also deals with earthing, among other circuit characteristics. Tokamaks are large-scale electrical installations that are known to generate large and low frequency magnetic fields as well as large and high frequency electric fields. Four European Tokamak installations have been investigated, from the earthing point of view, to identify appropriate techniques to earth the electrical equipment...

Perez, A.; Fasel, D.; Lister, Jb; Marle?taz, B.; Marmillod, P.; Siravo, U.

2010-01-01

297

Energy Balance, Climate, and Life - Work of M. Budyko  

Science.gov (United States)

This talk will review the work of Mikhail I. Budyko, author of "Climate and Life" and many other works, who died recently at age 81, in St Petersburg, Russia. He directed the Division for Climate Change Research at the State Hydrological Institute. We will explore Budyko's work in clarifying the role of energy balance in determining planetary climate, and the role of climate in regulating Earth s biosphere.

Cahalan, Robert F.

2004-01-01

298

Rough wall skin friction measurements using a high resolution surface balance  

International Nuclear Information System (INIS)

This paper describes the design of a floating element friction balance which is based upon a commercially available micro force balance. The balance has a perfectly linear calibration function and was successfully applied to rough wall flows in a channel and a diffusor. Extrapolation of the turbulent shear stress measured by two component LDA to the wall matched very well the shear stress measured using the friction balance. Also, the wall shear stress obtained from the balance in the fully developed channel flow agreed with the stress that could be derived from the pressure gradient to within 3%.

2010-06-01

299

26 CFR 1.430(f)-1 - Effect of prefunding balance and funding standard carryover balance.  

Science.gov (United States)

...prefunding balance and funding standard carryover balance. 1.430(f)-1 Section...prefunding balance and funding standard carryover balance. (a) In general â(1...application of prefunding and funding standard carryover balances under section...

2010-04-01

300

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.

 
 
 
 
301

Effects of the post-perovskite phase change on the thermal evolution of the Earth's core  

Science.gov (United States)

The heat flow through the core-mantle boundary is a key quantity for understanding the thermal evolution of the Earth??s core, as the geodynamo is presumably strongly affected by the temporal variation of CMB heat flow. A major challenge is to understand how this heat flux can have remained high enough to power the geodynamo over geological history without resulting in larger-than-observed cooling of the core and growth of the inner core. This problem has been approached using various coupled models of mantle convection and core heat balance: (1) Simple isochemical models using parameterized mantle convection and core heat balance [Buffett, 2002; Labrosse, 2003; Nimmo et al., 2004] have too rapid core cooling hence a too large inner core, (2) models with a global layer of dense material above the CMB [McNamara and van Keken, 2000] have a CMB heat flow that is too low for the geodynamo to occur, but (3) with discontinuous chemical layering [Nakagawa and Tackley, 2004], viable evolution solutions are obtained, with the best scenarios requiring 100-200 ppm radioactive potassium in the core [Nakagawa et al., 2004]. Recently, using high pressure experiments and ab initio calculations, a new perovskite to post-perovskite phase change was discovered near the CMB [Murakami et al., 2004; Oganov and Ono, 2004]. Dynamically, such a phase change results in small-scale instabilities in lower thermal boundary layer and higher CMB heat flow [Nakagawa and Tackley, 2004]. Furthermore, if the CMB is in the perovskite stability field then a double-crossing of the phase boundary may occur [Hernlund et al., 2005]. As the core and mantle cool with time, the location and thickness of the layer of post-perovskite phase will change [Nakagawa and Tackley, 2005]. In this study, a coupled model of thermo-chemical mantle convection including the post-perovskite phase change and a global heat balance in the core based on the entropy variation is used to assess the CMB heat flow, thermo-chemical structures in the D?? region (dense piles due to basaltic component and double-crossing due to the post-perovskite phase change) and their influence on the thermal history of the Earth??s core. The required amount of potassium in the core will be also discussed in this presentation.

Nakagawa, T.; Tackley, P. J.

2005-05-01

302

Skin friction balance  

Science.gov (United States)

A skin friction balance uses a parallel linkage mechanism to avoid inaccuracies in skin friction measurement attributable to off-center normal forces. The parallel linkage mechanism includes a stationary plate mounted in a cage, and an upper and lower movable plate which are linked to each other and to the stationary plate throught three vertical links. Flexure pivots are provided for pivotally connecting the links and the plates. A sensing element connected to the upper plate moves in response to skin friction, and the lower plate moves in the opposite direction of the upper plate. A force motor maintains a null position of the sensing element by exerting a restoring force in response to a signal generated by a linear variable differential transformer (LVDT).

Ping, Tcheng; Supplee, Frank H., Jr.

1989-06-01

303

Strategic Balanced Scorecard Simulation  

DEFF Research Database (Denmark)

The purpose of this article is to show how a System Dynamics Modelling approach can be integrated into the Balanced Scorecard (BSC) for a case company with special focus on the handling of causality in a dynamic perspective. The case companyâ??s BSC model includes five perspectives and a number of financial and non-financial measures. The overall idea of BSC is to make the strategy operational, as proposed by Kaplan and Norton (1992; 1996; 2007) and to use the strategy for simulation. Our results indicate that a company may gain great learning insight from such simulation studies. The whole article will be published in a coming issue of Journal of Business and Systems Research.

Nielsen, Steen; Nielsen, Erland Hejn

2012-01-01

304

Thermodynamics of hexagonal-close-packed iron under Earth’s core conditions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The free energy and other thermodynamic properties of hexagonal-close-packed iron are calculated by direct ab initio methods over a wide range of pressures and temperatures relevant to the Earth’s core. The ab initio calculations are based on density-functional theory in the generalized-gradient approximation, and are performed using the projector augmented wave approach. Thermal excitation of electrons is fully included. The Helmholtz free energy consists of three parts, associated with th...

Alfe, D.; Price, G. D.; Gillan, M. J.

2001-01-01

305

Apparatus for High-Pressure Thermogravimetry.  

Science.gov (United States)

Construction and operation of a high-pressure thermobalance usable to 300 psig and a temperature of 350C is described. A modified, commercially available balance mechanism and associated circuitry provide an apparatus that is easily constructed and has sa...

E. C. Penski H. A. Brown J. J. Callahan

1971-01-01

306

Energy Balance Models and Planetary Dynamics  

Science.gov (United States)

We know that planetary dynamics can have a significant affect on the climate of planets. Planetary dynamics dominate the glacial-interglacial periods on Earth, leaving a significant imprint on the geological record. They have also been demonstrated to have a driving influence on the climates of other planets in our solar system. We should therefore expect th.ere to be similar relationships on extrasolar planets. Here we describe a simple energy balance model that can predict the growth and thickness of glaciers, and their feedbacks on climate. We will also describe model changes that we have made to include planetary dynamics effects. This is the model we will use at the start of our collaboration to handle the influence of dynamics on climate.

Domagal-Goldman, Shawn

2012-01-01

307

Dynamic load balancing of applications  

Energy Technology Data Exchange (ETDEWEB)

An application-level method for dynamically maintaining global load balance on a parallel computer, particularly on massively parallel MIMD computers. Global load balancing is achieved by overlapping neighborhoods of processors, where each neighborhood performs local load balancing. The method supports a large class of finite element and finite difference based applications and provides an automatic element management system to which applications are easily integrated.

Wheat, Stephen R. (Albuquerque, NM)

1997-01-01

308

The reactive synthesis of the rare earth metals oxide films  

International Nuclear Information System (INIS)

There were investigated some characteristics of the rare earth metals oxide films reactive synthesis. The influence of the condensation temperature, deposition rate and oxygen pressure on to the films structure and properties are shown. It was established the effectivity of the reactive synthesis method for obtaining of high refractive, protective and corrosion resistant rare earth metals oxide layers

1999-01-01

309

Outline of earthing  

Energy Technology Data Exchange (ETDEWEB)

Expressed in its most basic terms, the function of earthing is that of making connection or contact with the body of the earth using systems of buried earth electrodes. The main ideas apply to earthing at a large generating station as they do for earthing at a single tower in an overhead line construction. Some basic principles are common to both. But the consideration on which earthing system design is based are very different in these two cases as are the earthing systems to which design leads. The paper provides an outline of the main principles and concepts underlying earthing and the design of all earthing systems. It does so at a time when there is a resurgence of interest in the subject. One of the issues examined is that of whether earthing requirements are the more stringent now than formerly and whether earthing problems have become increasingly more acute as power networks have expanded in geographical extent and in capacity. (author). 1 table. 2 refs.

Nguyen, T.T.; Humpage, W.D. [Western Australia Univ., Nedlands, WA (Australia)

1995-12-31

310

Earth Science Information Center  

Science.gov (United States)

An ESIC? An Earth Science Information Center. Don't spell it. Say it. ESIC. It rhymes with seasick. You can find information in an information center, of course, and you'll find earth science information in an ESIC. That means information about the land that is the Earth, the land that is below the Earth, and in some instances, the space surrounding the Earth. The U.S. Geological Survey (USGS) operates a network of Earth Science Information Centers that sell earth science products and data. There are more than 75 ESIC's. Some are operated by the USGS, but most are in other State or Federal agencies. Each ESIC responds to requests for information received by telephone, letter, or personal visit. Your personal visit.

U.S. Geological Survey

1991-01-01

311

Earth Science Students  

Science.gov (United States)

This site provides varied and vital information for earth science students. Links lead to important and interesting sites that change from time to time. The permanent pages at this site offer information that is of value to all earth science students and some that are for local students. There are animations and visual learning aids, interactive unit notes, practice questions for exams, earth science flash cards, supplementary Lessons, a course curriculum, and conversion calculators. The Current Earth Science page has real-time information about weather, volcanoes, earthquakes, and population. Other pages on this site list a host of earth science news items, earth science computer labs, all of the required earth science reference tables, a glossary, an "ask an expert" page, and a guestbook. Other links lead to information of local concern.

Burrows, Charles

312

Energy balance comparison of sorghum and sunflower  

Science.gov (United States)

An understanding of the energy exchange processes at the surface of the earth is necessary for studies of global climate change. If the climate becomes drier, as is predicted for northern mid-latitudes, it is important to know how major agricultural crops will play a role in the budget of heat and moisture. Thus, the energy balance components of sorghum [ Sorghum bicolor (L.) Moench.] and sunflower ( Helianthus annuus L.), two drought-resistant crops grown in the areas where summertime drying is forecasted, were compared. Soil water content and evapotranspiration ( ET) rates also were determined. Net radiation was measured with net radiometers. Soil heat flux was analyzed with heat flux plates and thermocouples. The Bowen ratio method was used to determine sensible and latent heat fluxes. Sunflower had a higher evapotranspiration rate and depleted more water from the soil than sorghum. Soil heat flux into the soil during the daytime was greater for sorghum than sunflower, which was probably the result of the more erect leaves of sorghum. Nocturnal net radiation loss from the sorghum crop was greater than that from the sunflower crop, perhaps because more heat was stored in the soil under the sorghum crop. But daytime net radiation values were similar for the two crops. The data indicated that models of climate change must differentiate nighttime net radiation of agricultural crops. Sensible heat flux was not always less (or greater) for sorghum compared to sunflower. Sunflower had greater daytime values for latent heat flux, reflecting its greater depletion of water from the soil. Evapotranspiration rates determined by the energy balance method agreed relatively well with those found by the water balance method. For example, on 8 July (43 days after planting), the ET rates found by the energy-balance and water-balance methods were 4.6 vs. 5.5 mm/day for sunflower, respectively; for sorghum, these values were 4.0 vs. 3.5 mm/day, respectively. If the climate does become drier, the lower soil water use and lower latent heat flux of sorghum compared to sunflower suggest that sorghum will be better adapted to the climate change.

Rachidi, F.; Kirkham, M. B.; Kanemasu, E. T.; Stone, L. R.

1993-03-01

313

Integral momentum balance on a growing bubble  

Science.gov (United States)

The integral momentum balance on a growing boiling bubble is investigated. All forces acting on the bubble are detailed, and the methods and assumptions used to calculate their integral resultants are discussed. The momentum balance computation is then performed using experimental data of bubbles growing on an artificial nucleation site in a controlled environment. The relative magnitude of each force component is compared, showing negligible dynamic forces, upwards forces composed mainly of the buoyancy and contact pressure components, and downwards forces being exclusively due to surface tension and adhesion. The difficulty encountered in measuring the apparent contact angle due to mirage effects has been highlighted; a new method, fitting numerically simulated bubble profile to the contour measurements has been proposed and used to correct the effects of refraction on the bubble profile determination. As all forces acting on the bubble were measured, it was possible to estimate the residuals of the momentum balance. Their small value validated both the expressions used for the forces and the methodology to evaluate their value.

Siedel, S.; Cioulachtjian, S.; Robinson, A. J.; Bonjour, J.

2013-12-01

314

Temperature response of Earth to the annual solar irradiance cycle  

CERN Document Server

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.

Douglass, D H; Knox, R S

2004-01-01

315

Temperature response of Earth to the annual solar irradiance cycle  

Energy Technology Data Exchange (ETDEWEB)

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.

Douglass, David H.; Blackman, Eric G.; Knox, Robert S

2004-03-22

316

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

317

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

318

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

319

Balancing Trust and Control  

DEFF Research Database (Denmark)

Dette papir fokuserer på ledelsesudfordringerne med at afbalancere tillid og kontrol. Forholdet mellem tillid og kontrol har i lang tid været en problem for ledelsesforskere. I papiret vises først at der har været en ændring i den måde, hvorpå forholdet mellem tillid og kontrol er blevet konceptualiseret i tillidsforskningen. Mens forholdet mellem tillid og kontrol tidligere blev set som et mere eller mindre stabil balance mellem tillid og kontrol, anskuer nyere forskning forholdet mellem tillid og kontrol som en dynamisk proces, der involverer en løbende afbalancering af forholdet mellem tillid og kontrol. For det andet, med udgangspunkt i en konceptualisering af balancen mellem tillid og kontrol som en interaktiv proces, drøftes udfordringerne for ledelsen i at håndtere denne mere subtile afbalancering af tillid og kontrol. Papiret konkluderer med at illustrere, hvordan denne mere detaljerede forståelse af samspillet mellem tillid og kontrol er nyttige for forståelsen af samspillet mellem tillid, kontrol ogselvkontrol i nye organisationsformer.

Jagd, Søren

320

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.)

1981-03-01

 
 
 
 
321

Balancing safety and economics  

Energy Technology Data Exchange (ETDEWEB)

The safety requirements of NPPs have always aimed at limiting societal risks. This risk approach initially resulted in deterministic design criteria and concepts. In the 1980s the paradigm 'safety at all costs' arose and often led to questionable backfitting measures. Conflicts between new requirements, classical design concepts and operational demands were often ignored. The design requirements for advanced reactors ensure enhanced protection against severe accidents. Still, it is questionable whether the 'no-damage-outside-the-fence' criteria can be achieved deterministically and at competitive costs. Market deregulation and utility privatisation call for a balance between safety and costs, without jeopardising basic safety concepts. An ideal approach must be risk-based and imply modern PSAs and new methods for cost-benefit and ALARA analyses, embed nuclear risks in a wider risk spectrum, but also make benefits transparent within the context of a broader life experience. Governments should define basic requirements, minimum standards and consistent comparison criteria, and strengthen operator responsibility. Internationally sufficient and binding safety requirements must be established and nuclear technology transfer handled in a responsible way, while existing plants, with their continuous backfitting investments, should receive particular attention. (orig.)

Kroeger, W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Fischer, P.U. [Elektrizitaets-Gesellschaft Laufenburg (EGL), Laufenburg (Switzerland)

2000-01-01

322

Balancing safety and economics  

International Nuclear Information System (INIS)

The safety requirements of NPPs have always aimed at limiting societal risks. This risk approach initially resulted in deterministic design criteria and concepts. In the 1980s the paradigm 'safety at all costs' arose and often led to questionable backfitting measures. Conflicts between new requirements, classical design concepts and operational demands were often ignored. The design requirements for advanced reactors ensure enhanced protection against severe accidents. Still, it is questionable whether the 'no-damage-outside-the-fence' criteria can be achieved deterministically and at competitive costs. Market deregulation and utility privatisation call for a balance between safety and costs, without jeopardising basic safety concepts. An ideal approach must be risk-based and imply modern PSAs and new methods for cost-benefit and ALARA analyses, embed nuclear risks in a wider risk spectrum, but also make benefits transparent within the context of a broader life experience. Governments should define basic requirements, minimum standards and consistent comparison criteria, and strengthen operator responsibility. Internationally sufficient and binding safety requirements must be established and nuclear technology transfer handled in a responsible way, while existing plants, with their continuous backfitting investments, should receive particular attention. (orig.)

2000-01-01

323

Older Adults and Balance Problems  

Medline Plus

Full Text Available ... have a serious impact on an older person's life. In fact, balance problems are one reason older people fall. A. ... three-legged stool. There are three systems that work with each other -- kind of organized by the brain -- to help us maintain our balance, or, another way of looking at it, our ...

324

Energy balance in UNF code  

International Nuclear Information System (INIS)

The energy balance for whole reaction processes must be taken into account to set up neutron data file. The formulations of the energy balance of the secondary particle emissions are presented. It is used in the UNF code. The double differential cross sections from continuum state to continuum state and from continuum state to discrete levels are given

2000-06-01

325

High pressure studies: metals, alloys and compounds. Chapter 9  

International Nuclear Information System (INIS)

A review of high pressure studies of the rare earths, their alloys and compounds is presented. The effect of pressure on structure, resistivity, and magnetic transitions is discussed in detail. (W.D.L.)

1978-01-01

326

Balancing alternative land uses in conservation prioritization.  

Science.gov (United States)

Pressure on ecosystems to provide various different and often conflicting services is immense and likely to increase. The impacts and success of conservation prioritization will be enhanced if the needs of competing land uses are recognized at the planning stage. We develop such methods and illustrate them with data about competing land uses in Great Britain, with the aim of developing a conservation priority ranking that balances between needs of biodiversity conservation, carbon storage, agricultural value, and urban development potential. While both carbon stocks and biodiversity are desirable features from the point of view of conservation, they compete with the needs of agriculture and urban development. In Britain the greatest conflicts exist between biodiversity and urban areas, while the largest carbon stocks occur mostly in Scotland in areas with low agricultural or urban pressure. In our application, we were able successfully to balance the spatial allocation of alternative land uses so that conflicts between them were much smaller than had they been developed separately. The proposed methods and software, Zonation, are applicable to structurally similar prioritization problems globally. PMID:21830691

Moilanen, Atte; Anderson, Barbara J; Eigenbrod, Felix; Heinemeyer, Andreas; Roy, David B; Gillings, Simon; Armsworth, Paul R; Gaston, Kevin J; Thomas, Chris D

2011-07-01

327

Variables Affecting Earth's Albedo  

Science.gov (United States)

Earth's albedo is the fraction of incoming radiation (sunlight) that is reflected into space. The Earth has an average albedo, which describes how much sunlight is reflected on average for the whole planet and the whole year. The Earth also has a local albedo, which determines how much of the Sun's light is reflected from a particular place at a particular time. The local albedo depends on the particular local surface, which can change seasonally as vegetation changes. It also depends on more rapidly changing things such as snow and clouds. In this lesson, students will investigate one of the variables that affect the Earth's albedo. They will collect and graph data on Earth's albedo from two surface types at the same latitude over a period of two years. They will then use the data to calculate how much difference there is in Earth's albedo between the two locations and suggest reasons for the differences.

328

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

International Nuclear Information System (INIS)

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

329

The energy cost for balance control during upright standing.  

Science.gov (United States)

The aim of this study was to investigate whether balance control during a static upright standing task with and without balance perturbations elicits a significant and meaningful metabolic energy demand and to test whether this energy demand correlates with conventional posturography measures for balance control. Ten healthy subjects were assessed in four 4-min upright standing conditions on a force platform while energy consumption was measured using open circuit respirometry. In the reference condition subjects stood upright in parallel stance without balance perturbation (PS). In the other conditions balance was perturbed by placing the subjects in tandem stance (TS), in tandem stance blind folded (TSBF) and in tandem stance on a balance board (TSBB). Gross and net energy consumption was assessed and various conventional posturography measures were derived from the excursion of the center of pressure (CoP) of the ground reaction force. Energy consumption was substantially affected by all balance perturbations, compared to the reference condition. The highest increase in energy consumption was found for the TSBF condition (increase of 0.86 J kg(-1)s(-1) or 60% of PS). Significant correlations were found between energy consumption and posturography measures. The strongest correlation was found between gross energy consumption and the CoP path and normalized CoP path along the anterior-posterior axis (resp. r=0.57 and r=0.66, p<0.001). It was concluded that the effort for balance control can elicit a meaningful metabolic energy demand. Conventional posturography provided significant, though moderate, predictors of this metabolic effort for balance control. PMID:19525114

Houdijk, Han; Fickert, Richard; van Velzen, Judith; van Bennekom, Coen

2009-08-01

330

Laptops: Earth and Environment  

... Laptops: Earth and Environment Faculty of Environment Leeds.ac.uk Portal Site map Contact Us School of Earth and Environment Home Admissions &...Consultancy People Intranet You are here: Earth and Environment Intranet logs & nbspLaptops Logfile for Field Laptops #1, #2, #...Add a new comment Displaying results 1 to 1 out of 1 Field Laptops Tuesday, 18-10-11 15:15 Start of Logfile Search site Faculties ...

331

Contact: Earth and Environment  

...Undergraduate Admissions Contacts, School of Earth and Environment, University of Leeds, BSc Honours Degree, BA Honours Degree, Environment, ...uk Portal Site map Contact Us School of Earth and Environment Home Admissions & Study Research Business & Consultancy People Intranet You ...are here: Earth and Environment Admissions & Study Undergraduate Contact Contact Undergraduate Admissions Team Telephone from UK: 0113 ...Telephone from outside UK: +44 113 343 6719 Email: admissions(at)see.leeds.ac.uk Ms Joanne (Jo) Siddons Admissions Administrator Telephone from UK: ...

332

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 report contains a general overview of the Earth's magnetic field. The different sources that contribute to the total magnetic field are presented and the diverse variations in the field are describ...

Edda Lína Gunnarsdóttir 1988

2012-01-01

333

The origin of the moon and the early history of the earth - a chemical model. Part 2: The earth  

International Nuclear Information System (INIS)

The geochemical implications for the earth of a giant impact model for the origin of the earth-moon system are discussed, using a mass balance between three components: the proto-earth, the Impactor, and a late veneer. It is argued that the proto-earth accretes from material resembling a high temperature condensate from the solar nebula. Core formation takes place under very reducing conditions, resulting in the mantle of the proto-earth being completely stripped of all elements more siderophile than Fe, and partly depleted in the barely siderophile elements V, Cr, and perhaps Si. The Impactor then collides with the proto-earth, causing vaporisation of both the Impactor and a substantial portion of the earth's mantle. Most of this material recondenses to the earth, but some forms the moon. The Impactor adds most of the complement of the siderophile elements of the present mantle in an oxidized form. The oxidation state of the mantle is set near to its present, oxidized level. Finally, the addition of a late veneer, of composition similar to that of the H-group ordinary chondrites, accounts for the complement of the highly siderophile elements of the present mantle. The model accounts at least semi-quantitatively for the siderophile element abundances of the present mantle. Implications for the composition of the earth's core are discussed; the model predicts that neither S, O, nor Si should be present in sufficient quantities to provide the required light element in the core, whose identity, therefore, remains enigmatic

1991-01-01

334

Economical distribution network earthing  

Energy Technology Data Exchange (ETDEWEB)

Ensuring safety for both power authority personnel and the public in the event of an earth fault is one of the primary purposes of an earthing system. An earthing system design based upon minimizing earth resistance will not guarantee safety, there is no simple relation between the resistance of the earthing system and the maximum shock current to which a person might be exposed. Therefore, the design and performance of an earthing system as a whole must be considered. This paper aims to describe hazardous situations and means by which the earthing system can be designed to minimize the risk. Design methods are outlined for a range of installation, aiming to provide compliance with the Electricity Supply Association of Australia (ESAA) safety criteria. Particular emphasis is given to providing adequate safety protection for customers `isolated` from the Multiple Earthed Neutral (MEN) System or Common Multiple Earthed Neutral (CMEN) System. Coordination between customer supply/design and field/installation staff has been found to result in significant benefits in system safety, estimating and installation. (author). 2 tabs., 6 figs., 8 refs.

Carman, B. [Safearth Engineered Solutions, Newcastle, NSW (Australia); Myors, P. [Orion Energy, Newcastle, NSW (Australia); Pearl, P. [South East Queensland Electricity Corporation, Brisbane, QLD (Australia)

1995-12-31

335

Pressurized water reactor pressurizer model  

International Nuclear Information System (INIS)

Pressurizer mathematical model for the Basic Principle Training Simulator is described. Mathematical model uses two continuity equations and energy conservation equation. For calculation of fluid mass flow drift-flux model is used. Pressurizer model with pressurizer level and pressurizer pressure control system is tested with simulation of the change surge line flow. (author)

1985-06-03

336

Heliotropic dust rings for Earth climate engineering  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper examines the concept of a Sun-pointing elliptical Earth ring comprised of dust grains to offset global warming. A new family of non-Keplerian periodic orbits, under the effects of solar radiation pressure and the Earth's J(2) oblateness perturbation, is used to increase the lifetime of the passive cloud of particles and, thus, increase the efficiency of this geoengineering strategy. An analytical model is used to predict the orbit evolution of the dust ring due to solar-radiat...

Bewick, R.; Luecking, C.; Colombo, C.; Sanchez, J. P.; Mcinnes, C. R.

2013-01-01

337

Erratum to "Pore pressure penetrometers document high overpressure near the seafloor where multiple submarine landslides have occurred on the continental slope, offshore Louisiana, Gulf of Mexico" [Earth and Planetary Science Letters 269/3-4 (2008) 309-32  

Science.gov (United States)

Overpressures measured with pore pressure penetrometers during Integrated Ocean Drilling Program (IODP) Expedition 308 reach 70% and 60% of the hydrostatic effective stress (?*=(u-u)(?vh')) in the first 200 meters below sea floor (mbsf) at Sites U1322 and U1324, respectively, in the deepwater Gulf of Mexico, offshore Louisiana. High overpressures are present within low permeability mudstones where there have been multiple, very large, submarine landslides during the Pleistocene. Beneath 200 mbsf at Site U1324, pore pressures drop significantly: there are no submarine landslides in this mixture of mudstone, siltstone, and sandstone. The penetrometer measurements did not reach the in situ pressure at the end of the deployment. We used a soil model to determine that an extrapolation approach based on the inverse of square root of time (1/t) requires much less decay time to achieve a desirable accuracy than an inverse time (1/t) extrapolation. Expedition 308 examined how rapid and asymmetric sedimentation above a permeable aquifer drives lateral fluid flow, extreme pore pressures, and submarine landslides. We interpret that the high overpressures observed are driven by rapid sedimentation of low permeability material from the ancestral Mississippi River. Reduced overpressure at depth at Site U1324 suggests lateral flow (drainage) whereas high overpressure at Site U1322 requires inflow from below: lateral flow in the underlying permeable aquifer provides one mechanism for these observations. High overpressure near the seafloor reduces slope stability and provides a mechanism for the large submarine landslides and low regional gradient (2 degree) offshore from the Mississippi delta.

Iodp Expedition 308 Scientists; Flemings, P. B.; Long, H.; Dugan, B.; Germaine, J.; John, C. M.; Behrmann, J. H.; Sawyer, D.; IODP Expedition 308 Scientists

2008-09-01

338

Thermal balance testing of MSAT 2 spacecraft  

Science.gov (United States)

The present work reports on the recently completed infrared thermal balance/thermal vacuum testing of a MSAT satellite, the first satellite to provide mobile communications service for all of continental North America. MSAT is a two spacecraft program, using a three-axis stabilized Hughes HS-601 series Bus as the vehicle for the Canadian designed Payload. The thermal tests which were performed at the Canadian Space Agency's David Florida Laboratory in Ottawa, Canada, lasted approximately 35 days. The infrared (IR) heating rig was designed to provide radiant heat inputs into seven spacecraft zones during Thermal Vacuum (TV) testing. The TV test was divided into multiple phases. It began with a thermal balance cold phase, followed by a thermal cold cycle and a hot balance phase, complemented by a thermal hot cycle to finish with a thermal cycle with continuous monitoring of the Bus and Payload. The spacecraft's external heat fluxes were provided by IR lamp sources. To ensure flux uniformity, highly reflective baffles and IR East and West faces; the Earth facing (Nadir); and the inside of the thrust cylinder. The aft-end panel heat fluxes were provided by a heated LN2 shroud. The radiation flux intensity on the spacecraft zones from the various rig elements was measured using Monitored Background Radiometers (MBR's) and compared with direct calculations and with pretest predictions. The temperature measurement system was based on Uniform Temperature References (UTR's) located inside the chamber such that all feedthroughs were copper-copper. This system was devised to achieve a temperature measurement accuracy of plus/minus 0.5 C for over 850 thermocouples used in the test. A PC-(QNX-based) based real-time data acquisition system was utilized to provide continuous monitoring of all channels based on a 30-second time scan. In addition, the data acquisition system was able to retrieve telemetry stream from the Satellite Test Equipments (STE) station for real-time data manipulation. Preliminary results showed the test to be successful from both the thermal balance side and the electrical testing side.

Samson, Serge; Choueiry, Elie

1994-01-01

339

Calibration and Data Analysis of the MC-130 Air Balance  

Science.gov (United States)

Design, calibration, calibration analysis, and intended use of the MC-130 air balance are discussed. The MC-130 balance is an 8.0 inch diameter force balance that has two separate internal air flow systems and one external bellows system. The manual calibration of the balance consisted of a total of 1854 data points with both unpressurized and pressurized air flowing through the balance. A subset of 1160 data points was chosen for the calibration data analysis. The regression analysis of the subset was performed using two fundamentally different analysis approaches. First, the data analysis was performed using a recently developed extension of the Iterative Method. This approach fits gage outputs as a function of both applied balance loads and bellows pressures while still allowing the application of the iteration scheme that is used with the Iterative Method. Then, for comparison, the axial force was also analyzed using the Non-Iterative Method. This alternate approach directly fits loads as a function of measured gage outputs and bellows pressures and does not require a load iteration. The regression models used by both the extended Iterative and Non-Iterative Method were constructed such that they met a set of widely accepted statistical quality requirements. These requirements lead to reliable regression models and prevent overfitting of data because they ensure that no hidden near-linear dependencies between regression model terms exist and that only statistically significant terms are included. Finally, a comparison of the axial force residuals was performed. Overall, axial force estimates obtained from both methods show excellent agreement as the differences of the standard deviation of the axial force residuals are on the order of 0.001 % of the axial force capacity.

Booth, Dennis; Ulbrich, N.

2012-01-01

340

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

 
 
 
 
341

Ocular perfusion pressure in glaucoma.  

Science.gov (United States)

This review article discusses the relationship between ocular perfusion pressure and glaucoma, including its definition, factors that influence its calculation and epidemiological studies investigating the influence of ocular perfusion pressure on the prevalence, incidence and progression of glaucoma. We also list the possible mechanisms behind this association, and discuss whether it is secondary to changes in intraocular pressure, blood pressure or both. Finally, we describe the circadian variation of ocular perfusion pressure and the effects of systemic and topical medications on it. We believe that the balance between IOP and BP, influenced by the autoregulatory capacity of the eye, is part of what determines whether an individual will develop optic nerve damage. However, prospective, longitudinal studies are needed to better define the role of ocular perfusion pressure in the development and progression of glaucoma. PMID:24238296

Costa, Vital P; Harris, Alon; Anderson, Douglas; Stodtmeister, Richard; Cremasco, Fernanda; Kergoat, Helene; Lovasik, John; Stalmans, Ingborg; Zeitz, Oliver; Lanzl, Ines; Gugleta, Konstantin; Schmetterer, Leopold

2014-06-01

342

Nuclear reactor pressure vessels  

International Nuclear Information System (INIS)

Reference is made to gas cooled reactors having pre-stressed concrete pressure vessels. Such pressure vessels entail the use of high grade thermal insulation, capable of satisfactory use in high pressure gas environments, in order to combat the sensitivity of concrete to high temperature. Temperature limitations both in regard to absolute temperature and allowable gradients through the vessel walls require the use of a protective thermal barrier on the inside of the pressure vessel wall to separate the gas coolant from the concrete. This barrier must also be designed to withstand, or be isolated from, the intense noise arising from the gas circulators. In the arrangement described the thermal barrier system comprises a metal liner to which is fixed an impervious inner metal membrane having flexible corrugated thinner metal portions. Heat resistant ilsultation is held between the metal liner and the inner membrane, and fitted vents are located between the insulation and the interior of the vessel for balancing the the pressure within the insulation and to provide controlled maximum pressure differential porting. The studs fixing the inner metal membrane to the metal liner may be hollow and act as the filter vents. (U.K.)

1975-01-01

343

Physical load handling and listening comprehension effects on balance control.  

Science.gov (United States)

The purpose of this study was to determine the physical load handling and listening comprehension effects on balance control. A total of 16 young and 16 elderly participants were recruited in this study. The physical load handling task required holding a 5-kg load in each hand with arms at sides. The listening comprehension task involved attentive listening to a short conversation. Three short questions were asked regarding the conversation right after the testing trial to test the participants' attentiveness during the experiment. Balance control was assessed by centre of pressure-based measures, which were calculated from the force platform data when the participants were quietly standing upright on a force platform. Results from this study showed that both physical load handling and listening comprehension adversely affected balance control. Physical load handling had a more deleterious effect on balance control under the listening comprehension condition vs. no-listening comprehension condition. Based on the findings from this study, interventions for the improvement of balance could be focused on avoiding exposures to physically demanding tasks and cognitively demanding tasks simultaneously. STATEMENT OF RELEVANCE: Findings from this study can aid in better understanding how humans maintain balance, especially when physical and cognitive loads are applied. Such information is useful for developing interventions to prevent fall incidents and injuries in occupational settings and daily activities. PMID:21108083

Qu, Xingda

2010-12-01

344

Google Earth Lessons  

Science.gov (United States)

This collection of links to lessons, tools and tips is intended for teachers who want to use Google Earth in the classroom. Resources include lesson plans, videos, virtual tours, and other multimedia features. It includes a set of guidelines for using the resources and instructions for using Google Earth itself. Users can also add lessons of their own.

Douglass, David

2006-01-01

345

XRF: Earth and Environment  

... XRF: Earth and Environment Faculty of Environment Leeds.ac.uk Portal Site map Contact Us School of Earth and Environment Home Admissions &... Facilities XRD/XRF Laboratory & gt XRF XRF Facility The department has an Olympus Innovex X-5000 portable XRF. has a Rh source ...

346

Rare earth permanent magnets  

International Nuclear Information System (INIS)

A survey is given of the state of the art in rare earth permanent magnet research of materials based on Nd2Fe14B. The magnetic properties of various types of interstitially modified Fe-rich rare earth intermetallics are discussed, including the possibility to apply these materials in permanent magnets. ((orig.))

1995-02-09

347

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

348

Improving Balance with Tai Chi  

Science.gov (United States)

... sensory input received by the brain from touch sensors in the muscles and joints—in the balancing ... made possible by the program’s careful attention to building on previous progress. A user-friendly resource package ...

349

What is flux balance analysis?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Flux balance analysis is a mathematical approach for analyzing the flow of metabolites through a metabolic network. This primer covers the theoretical basis of the approach, several practical examples and a software toolbox for performing the calculations.

Orth, Jeffrey D.; Thiele, Ines; Palsson, Bernhard Ø.

2010-01-01

350

Older Adults and Balance Problems  

Medline Plus

Full Text Available ... way of looking at it, our orientation in space. The inner ear organ of balance is the ... have receptors telling you where you are in space. Narrator: Some of the symptoms a person with ...

351

Aging: Balancing regeneration and cancer  

Energy Technology Data Exchange (ETDEWEB)

The proliferation of cells must balance the longevity assured by tissue renewal against the risk of developing cancer. The tumor-suppressor protein p16{sup INK4a} seems to act at the pivot of this delicate equilibrium.

Beausejour, Christian M.; Campisi, Judith

2006-08-24

352

Exercise to Improve Your Balance  

Science.gov (United States)

... the Go4Life website. As you progress in your exercise routine, try adding the following challenges to help ... steady on your feet, try doing the balance exercises with your eyes closed. Quick Tip In the ...

353

The Energy Balance of Granulation.  

Science.gov (United States)

Columnar models of the solar granulation based on the balance of convective energy carried by a vertical velocity field and radiation are constructed. A specified velocity field and perturbation of the radiative flux determines the variation of temperatur...

S. Musman G. D. Nelson

1975-01-01

354

Are Social Networks Really Balanced?  

CERN Document Server

There is a long-standing belief that in social networks with simultaneous friendly/hostile interactions (signed networks) there is a general tendency to a global balance. Balance represents a state of the network with lack of contentious situations. Here we introduce a method to quantify the degree of balance of any signed (social) network. It accounts for the contribution of all signed cycles in the network and gives, in agreement with empirical evidences, more weight to the shorter than to the longer cycles. We found that, contrary to what is believed, many signed social networks -- in particular very large directed online social networks -- are in general very poorly balanced. We also show that unbalanced states can be changed by tuning the weights of the social interactions among the agents in the network.

Estrada, Ernesto

2014-01-01

355

General Earth's Rotation Theory  

Science.gov (United States)

In the present paper the equations of the translatory motion of the major planets and the Moon and the equations of the three--axial solid Earth's rotation in Euler parameters are reduced to the secular system describing the evolution of the planetary and lunar orbits (independent of the Earth's rotation) and the evolution of the Earth's rotation (depending on the planetary and lunar evolution). Hence, the theory of the Earth's rotation is presented by means of the series in powers of the evolutionary variables with quasi-periodic coefficients. This form of the Earth's rotation problem is compatible with the general planetary theory involving the separation of the short-period and long-period variables and avoiding the appearance of the non-physical secular terms.

Brumberg, Victor A.; Ivanova, T. V.

2010-05-01

356

Multi-Layers Balanced LKH  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Secure multicast communication is important for applications such as pay-per-view distribution. LKH has been proposed to distribute a shared secret key in a way that scales efficiently for groups with many members. However, the efficiency of LKH depends critically on whether the key tree remains balanced. For applications such as video streaming or online teaching, several multicast sessions might be related in one way or another. in this paper, we consider the balance of the key tree and ...

Ng, Wee Hock Desmond; Sun, Zhili

2005-01-01

357

Electric power balance sheet 2012  

International Nuclear Information System (INIS)

The mission of RTE, the French electricity Transportation grid, a public service assignment, is to balance the electricity supply and demand in real time. This report presents RTE's technical results for the year 2012: strong seasonal contrast of power consumption, rise of the renewable energies contribution in meeting the electricity demand, slight decay of the nuclear and thermal power generation, decrease of the export balance and change in trades structure, adaptation of RTE's network to the evolutions of the energy system

2013-01-01

358

Integral design of reactor pressure vessels  

International Nuclear Information System (INIS)

Integral design applied to PWR pressure vessels allows one to obtain a moderate stress level due to a better balance of the material in the geometry; to reach a high quality and safety level of the pressure boundary; to improve the inservice inspection (ISI) operations; and to simplify the manufacturing operations. (author)

1979-03-08

359

Digital Earth reloaded - Beyond the next generation  

Science.gov (United States)

Digital replicas (or 'mirror worlds') of complex entities and systems are now routine in many fields such as aerospace engineering; archaeology; medicine; or even fashion design. The Digital Earth (DE) concept as a digital replica of the entire planet occurs in Al Gore's 1992 book Earth in the Balance and was popularized in his speech at the California Science Center in January 1998. It played a pivotal role in stimulating the development of a first generation of virtual globes, typified by Google Earth that achieved many elements of this vision. Almost 15 years after Al Gore's speech, the concept of DE needs to be re-evaluated in the light of the many scientific and technical developments in the fields of information technology, data infrastructures, citizen?s participation, and earth observation that have taken place since. This paper intends to look beyond the next generation predominantly based on the developments of fields outside the spatial sciences, where concepts, software, and hardware with strong relationships to DE are being developed without referring to this term. It also presents a number of guiding criteria for future DE developments.

Ehlers, M.; Woodgate, P.; Annoni, A.; Schade, S.

2014-02-01

360

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

 
 
 
 
361

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

International Nuclear Information System (INIS)

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

362

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

363

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)

2011-08-01

364

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

2011-05-01

365

steinberger: Earth and Environment  

... steinberger: Earth and Environment Faculty of Environment Leeds.ac.uk Portal Site map Contact Us School of Earth and Environment Home Admissions &...Intranet You are here: Earth and Environment Admissions & Study Research Degrees SRI steinberger Sustainability Research (SRI) PhD Projects Identifying and learning from ...sustainable development pathways Supervisors: Dr J Steinberger Most industrialized countries have already attained unsustainable levels of resource use and ensuing emissions, and most ... Suggested references: Steinberger, JK; Roberts, JT (2010): From constraint to sufficiency: the decoupling of energy and ...

366

Earth from Space  

Science.gov (United States)

The NASA Space Shuttle Earth Observations Photography database contains over 400,000 images. This website contains selected photos and related captions, published on the Internet to provide a glimpse of this national treasure to the public. This database was compiled to illustrate some very interesting Earth features and processes, such as deforestation, weather, oil drilling, and cities as seen by astronauts from space. Earth from Space provides several ways to search the selected images, including a clickable map or a search by features. Each image is available in three resolutions and includes cataloging data and a detailed caption. Prints and slides are available for purchase.

2002-04-08

367

The Earth's Magnetic Field  

Science.gov (United States)

The magnetic field of the Earth is contained in a region called the magnetosphere. The magnetosphere prevents most of the particles from the sun, carried in solar wind, from hitting the Earth. This site, produced by the University Corporation for Atmospheric Research (UCAR), uses text, scientific illustrations,and remote imagery to explain the occurrence and nature of planetary magnetic fields and magnetospheres, how these fields interact with the solar wind to produce phenomena like auroras, and how magnetic fields of the earth and other planets can be detected and measured by satellite-borne magnetometers.

368

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

369

Programme: Earth and Environment  

...uk Portal Site map Contact Us School of Earth and Environment Home Admissions & Study Research Business & Consultancy People Intranet You ...15 Overview of magnetic field generation in the deep Earth Chris Jones (Leeds) 13.45 Overview of risk from space weather Jim ...20 Forecasting the Earth's magnetic field Susan Macmillan (BGS) 16.40 Opportunities for the Swarm mission: the Ring Current Malcolm Dunlop ...20 The history of the South Atlantic Anomaly Vincent Lesur (GFZ) 10.40 Using core-flows as a predictive tool Ciaran Beggan (...

370

Tandem mirror reactor power balance studies  

International Nuclear Information System (INIS)

A tandem mirror reactor (TMR) power plant balance model has been developed and is now being used as a computer aid for performing parametric studies. End-cell power injection into the plasma and the physics thermal Q are used to determine the fusion power. About 80% of the fusion power is transferred by high-energy neutrons to the blanket modules and structures. The other 20% of the fusion power in the high-energy alpha particles is used to heat the deuterium-tritium (D-T) plasma. Most of the plasma-ionized particles transfer their energy to the halo dumps and direct converters. The plant efficiency is calculated for three different system cycles: (1) the pressurized water/saturated steam cycle; (2) the superheated steam cycle; and (3) the more complex superheat/reheat cycle. There is a signficiant improvement in plant efficiency as the electrical power multiplication factor and steam cycle efficiency increases

1985-03-03

371

Tandem Mirror Reactor power balance studies  

International Nuclear Information System (INIS)

A Tandem Mirror Reactor (TMR) power plant balance model has been developed and is now being used as a computer aid for performing parametric studies. End-cell power injection into the plasma and the physics plasma Q are used to determine the fusion power. About 80% of the fusion power is transferred by high-energy neutrons to the blanket modules and structures. The other 20% of the fusion power in the highenergy alpha particles is used to heat the deuterium-tritium (D-T) plasma. Most of the plasma-ionized particles transfer their energy to the halo dumps and direct converters. The plant efficiency is calculated for three different system cycles: (1) the pressurized water/saturated steam cycle, (2) the superheated steam cycle, and (3) the more complex superheat/reheat cycle. There is a significant improvement in plant efficiency as the electrical power multiplication factor and steam cycle efficiency increases

1985-07-01

372

Earth to Saturn, Earth to Saturn!  

Science.gov (United States)

This is a lesson about Saturn. Learners will use drawing and writing to explore the comparative features of Saturn and Earth. To scaffold student writing, the lesson includes a drawing activity, a brainstorming activity, a structured Cloze activity, and a chance for independent writing where students create their own analogies. This is lesson 6 of 10 in the Mission to Saturn Educators Guide, Reading Writing Rings, for grades 1-2.

373

Independent effects of adding weight and inertia on balance during quiet standing  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Human balance during quiet standing is influenced by adding mass to the body with a backpack, with symmetrically-applied loads to the trunk, or with obesity. Adding mass to the body increases both the weight and inertia of the body, which theoretically could provide counteracting effects on body dynamics and balance. Understanding the independent effects of adding weight and inertia on balance may provide additional insight into human balance that could lead to novel advancements in balance training and rehabilitation. Therefore, the purpose of this study was to investigate the independent effects of adding weight and inertia on balance during quiet standing. Methods Sixteen normal-weight young adult participants stood as still as possible on a custom-built backboard apparatus under four experimental conditions: baseline, added inertia only, added weight only, and added inertia and weight. Results Adding inertia by itself had no measurable effect on center of pressure movement or backboard movement. Adding weight by itself increased center of pressure movement (indicated greater effort by the postural control system to stand as still as possible and backboard movement (indicating a poorer ability of the body to stand as still as possible. Adding inertia and weight at the same time increased center of pressure movement but did not increase backboard movement compared to the baseline condition. Conclusions Adding inertia and adding weight had different effects on balance. Adding inertia by itself had no effect on balance. Adding weight by itself had a negative effect on balance. When adding inertia and weight at the same time, the added inertia appeared to lessen (but did not eliminate the negative effect of adding weight on balance. These results improve our fundamental understanding of how added mass influences human balance.

Costello Kerry

2012-04-01

374

Extremophiles: Link between earth and astrobiology  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Astrobiology studies the origin, evolution, distribution and future of life in the universe. The most promising worlds in Solar system, beyond Earth, which may harbor life are Mars and Jovian moon Europa. Extremophiles are organisms that thrive on the edge of temperature, hypersalinity, pH extremes, pressure, dryness and so on. In this paper, some extremophile cyanobacteria have been discussed as possible life forms in a scale of astrobiology. Samples were taken from solenetz and solonchak ty...

2008-01-01

375

Person detail: Earth and Environment  

... There I worked on numerical modelling of flow in fault damage zones where the fractures form partial flow barriers, in collaboration with Rob Knipe and Simon Harris (a NERC project). Present position and activities In 2004, I joined the staff in the School of Earth and Environment as a lecturer and set up the MSc in Hydrogeology of which I am currently Programme Manager. During my ...003 West LJ; Odling NE (2013) Groundwater, In: Holden J (Ed) Water Resources, Routledge, pp.123-160. Hussein MEA; Odling NE; Clark RA (2013) Borehole water level response to barometric pressure as an indicator of aquifer vulnerability, Water Resources Research, 49, pp.7102-7119. doi: 10.1002/2013WR014134 Keim DM; West LJ; Odling NE (2012) Convergent Flow ...

376

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

377

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

378

Infrared radiation in the energy balance of the upper atmosphere  

International Nuclear Information System (INIS)

The contribution of the infrared radiation to the energy balance of the Earth's upper atmosphere is discussed. The theoretical analysis has been carried out of the mechanisms of the transformation of the energy of outgoing particles and the ultraviolet-radiation of the Sun absorbed at the heights of Z >= 90 km into the infrared radiation. It is found out the the infrared radiation within the wave length range of 1.2-20 ? is more intensive that the 63 ? radiation of atomic oxygen and plays an important role in the general energy balance and the thermal regime of the thermosphere. It has been found out too that in the area of Z >= 120 km heights the radiation in the 5.3 ? NO band is the most intensive. This radiation is to be considered for the more accurate description of parameters of the atmosphere (temperature, density) conditioning the nature of the translocation of ionospheric sounds (ISS)

1977-01-01

379

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

380

CFD application for coal/air balancing in power plants  

Energy Technology Data Exchange (ETDEWEB)

Unbalanced coal/air flow in the pipe systems of coal-fired power plants will lead to non-uniform combustion in the furnace, and hence a overall lower efficiency of the boiler. A common solution to this problem is to put orifices in the pipe systems to balance the flow. It is well known that if the orifices are sized to balance clean air flow to individual burners connected to a pulverizer, the coal/air flow would still be unbalanced and vice versa. However, the current power industry practice throughout the world is to size orifices for balancing the clean air flow and accept the resulting imbalance in coal/air flow. Field tests are mostly conducted to verify a balanced clean air flow. It is now proposed to size the orifices for balancing the coal/air flow and then calculate the unbalanced clean air flow distribution to be known as the 'tailored clean air flow'. Commercially available Computational Fluid Dynamics (CFD) code CFX was used to simulate the complex flows in the piping systems in a power plant. The two-phase modelling technique was employed to estimate the pressure drop coefficients with both clean air and coal/air flows in order to size the orifices. The results indicate that the pressure drop is strongly dependent on the piping system geometry. With this proposed method, field tests can be conducted to correspond with the tailored clean air flow, and the coal/air flow balancing would be achieved.

Vijiapurapu, S.; Cui, J.; Munukutla, S. [Tennessee Technological University, Cookeville, TN (United States). Dept. for Engineering Mechanics

2006-09-15

 
 
 
 
381

The Earth's rotation problem  

Science.gov (United States)

The aim of the present paper is to find the trigonometric solution of the equations of the Earth's rotation around its centre of mass in the form of polynomial trigonometric series (Poisson series) without secular and mixed therms. For that the techniques of the General Planetary Theory (GPT) ( Brumberg, 1995) and the Poisson Series Processor (PSP) (Ivanova, 1995) are used. The GPT allows to reduce the equations of the translatory motion of the major planets and the Moon and the equations of the Earth's rotation in Euler parameters to the secular system describing the evolution of the planetary and lunar orbits (independent of the Earth's rotation) and the evolution of the Earth's rotation (depending on the planetary and lunar evolution).

Brumberg, V. A.; Ivanova, T. V.

2008-09-01

382

Geography World - Earth's Land  

Science.gov (United States)

Users of this portal can access information on mountains, islands, and other landforms of the Earth. Links are provided to a variety of materials, including books, maps, atlases, photographs and imagery, games and quizzes.

383

Earth's electric field  

International Nuclear Information System (INIS)

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 60"0, 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

384

Rare earth lasers  

International Nuclear Information System (INIS)

Whereas the use of rare earths for liquid and gaseous lasers has been limited, in the realm of solid state lasers they have been the dominant dopant ion, having lased in over 250 different ion-crystal combinations and innumerable glasses. The most widely used solid state laser is the Nd-doped Y/sub 3/A/sub 5/O/sub 12/ (YAG) laser: the largest lasers are Nd:glass lasers used for inertial confinement fusion research. In this brief survey, the authors review some of the key spectroscopic properties of rare earth that account for their versatility, examine recent research trends and developments, and comment upon future prospects for rare earth lasers. For gaseous and liquid lasers, other elements and molecules have thus far demonstrated lasing properties more attractive than those available using rare earths. Solid state lasers are examined

1985-01-01

385

Gambling with the earth  

CERN Multimedia

The probability that dangerous Earth-devouring particles will be born at a new accelerator in the US may be tiny, but scientists have played down the devastating potential costs in their risk assessments according to a physicist (1 page).

Muir, H

2000-01-01

386

Pressure Sores  

Science.gov (United States)

Pressure sores are areas of damaged skin caused by staying in one position for too long. They commonly form ... or are unable to change your position. Pressure sores can cause serious infections, some of which are ...

387

Peer Pressure  

Science.gov (United States)

... She'd just had a big dose of peer pressure. Who Are Your Peers? When you were a ... adults — parents, teachers, guidance counselors, etc. — talk about peer pressure more than the benefits of belonging to a ...

388

Rare earth ceramic scintillator  

International Nuclear Information System (INIS)

An improved scintillator for a solid state radiation detector useful in CT (computed tomography), DR (digital radiography), and related technologies. The scintillator, rather than being grown as a single crystal, is formed by means of hot pressing or sintering, as a polycrystalline ceramic. Rare earth oxides doped with rare earth activators are selected to yield a cubic crystal structure of high density and transmittance, which satisfies radiation detector requirements better than crystals utilized heretofore

1985-01-01

389

EARTH ROADS ARE EASY  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 fr...

2000-01-01

390

Bray: Earth and Environment  

... Bray: Earth and Environment Faculty of Environment Leeds.ac.uk Portal Site map Contact Us Faculty of Environment Home Admissions & Study Research Business & Consultancy People Intranet You are here: Earth and Environment Research ESSI Cohen Research ...Group Users' Blog Bray Back to article list Chasing Ice and the power of the 'big screen' chasingice.co.uk By Andy Bray (January 2013) Last week, a group of us from the Cohen Research Group went to see a new movie. ...

391

Earth construction: bird teaching  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The paradigm of earth being a traditional and a modern building material has been related to the fact that it is natural, ecological, recycled, abundant and economic. Among the traditional Portuguese building techniques, earth construction was always one very common. The construction built with these techniques must be preserved. In this context, the main objective of this research work is to give a contribution on the material properties characterization and, in particular, for t...

Silva, B.; Correia, J.; Nunes, F.; Tavares, P.; Varum, H.; Pinto, J.

2009-01-01

392

Fuller's earth (montmorillonite) pneumoconiosis.  

Science.gov (United States)

A fuller's earth worker developed signs of pneumoconiosis. Pathological examination of the lung tissues showed interstitial collections of dust laden macrophages associated with mild fibrosis. Mineralogical analysis showed a high content of montmorillonite. This study shows that a pneumoconiosis can result from prolonged heavy exposure to calcium montmorillonite (fuller's earth) in the absence of quartz. The disease is relatively mild and associated with little clinical disability. PMID:7951799

Gibbs, A R; Pooley, F D

1994-09-01

393

Fuller's earth (montmorillonite) pneumoconiosis.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A fuller's earth worker developed signs of pneumoconiosis. Pathological examination of the lung tissues showed interstitial collections of dust laden macrophages associated with mild fibrosis. Mineralogical analysis showed a high content of montmorillonite. This study shows that a pneumoconiosis can result from prolonged heavy exposure to calcium montmorillonite (fuller's earth) in the absence of quartz. The disease is relatively mild and associated with little clinical disability.

Gibbs, A. R.; Pooley, F. D.

1994-01-01

394

NASA Earth science missions  

Science.gov (United States)

NASA's Earth Science Division (ESD) conducts pioneering work in Earth system science, the interdisciplinary view of Earth that explores the interaction among the atmosphere, oceans, ice sheets, land surface interior, and life itself that has enabled scientists to measure global and climate changes and to inform decisions by governments, organizations, and people in the United States and around the world. The ESD makes the data collected and results generated by its space missions accessible to other agencies and organizations to improve the products and services they provide, including air quality indices, disaster management, agricultural yield projections, and aviation safety. Through partnerships with national and international agencies, NASA enables the application of this understanding. The ESD's Flight Program provides the spacebased observing systems and supporting ground segment infrastructure for mission operations and scientific data processing and distribution that support NASA's Earth system science research and modeling activities. The Flight Program currently has 15 operating Earth observing space missions, including the recently launched Landsat-8/Landsat Data Continuity Mission (LDCM). The ESD has 16 more missions planned for launch over the next decade. These include first and second tier missions from the 2007 Earth Science Decadal Survey, Climate Continuity missions to assure availability of key data sets needed for climate science and applications, and small-sized competitively selected orbital missions and instrument missions of opportunity utilizing rideshares that are part of the Earth Venture (EV) Program. The recently selected Cyclone Global Navigation Satellite System (CYGNSS) microsatellite constellation and the Tropospheric Emissions: Monitoring of Pollution (TEMPO) instrument are examples. In addition, the International Space Station (ISS) is being increasingly used to host NASA Earth observing science instruments. An overview of plans and current status will be presented.

Neeck, Steven P.; Volz, Stephen M.

2013-10-01

395

SNOWCARBO: CO2 Balance of Northern Terrestrial Ecosystem  

Science.gov (United States)

Today the anthropogenic carbon sources are producing more carbon dioxide into the atmosphere than is being absorbed by carbon sinks in terrestrial ecosystems and the oceans. This contributes towards the instability in the natural balance of carbon dioxide. The excess carbon dioxide warms the atmosphere, as a result causing global warming. In order to formulate environmental legislations, regulations and adaptation strategies to address the issues of climate change, it is essential to monitor and retrieve information on the magnitudes and locations of real natural carbon sources and sinks. In the northern terrestrial ecosystem, both carbon sources and sinks are affected by seasonal changes in snow cover. Changes in snow melting times during the spring and soil freezing in the autumn affect the length of the growing season and consequently, the ecosystem net productivity. As result spatial variability and long-term trends in snow cover distribution and related climate patterns need to be analyzed based on observation data and climate change prediction models. These models project changes in the spatial and temporal distribution of snow in boreal and arctic terrestrial regions. The main objective of the Snowcarbo project is to implement and demonstrate a new innovative approach for the net CO2 balance mapping in northern Finland and northern Eurasian region. This approach is based on a combination of different information sources describing snow evolution, phenology, land cover, CO2 fluxes and concentrations. The implemented method combines local in-situ observations and global Earth observation satellite data together with land cover class information in a new way. Snowcarbo aims to produce carbon dioxide balance maps over northern Finland and northern Eurasia by combining different earth observation data sources and modeling of CO2 balance. The results can be implemented into the European and national adaptation strategies to the impacts of climate change and to support the formulation of the environmental legislations and regulations.

Partamies, N. J.; Arslan, A. N.; Torma, M.; Markkanen, T.; Bottcher, K.; Harma, P.; Pulliainen, J. T.

2010-12-01

396

Redox balance in cystic fibrosis.  

Science.gov (United States)

The homeostatic balance between oxidants and antioxidants in biological systems is known as redox balance, and is regulated by complex processes. Redox balance regulates many of the known cellular pathways and disease processes. The dysregulation of redox balance can lead to acute or long-term oxidative or reductive stresses that are associated with many of the abnormalities observed in cystic fibrosis (CF). Over the past 5 decades researchers have examined contributors to redox dysregulation, their molecular products, and their impact on ion transport, cell proliferation, inflammation, bacterial killing, and the metabolism of nucleic acids, proteins, and lipids in CF. CF patients exhibit elevated markers of oxidative stress when compared to non-CF healthy controls; however, whether the reported redox imbalance is sufficient to produce pathology has been controversial. In addition, comparisons between CF and non-CF disease controls have been lacking. To better understand the mechanisms which mediate the generation of oxidants and antioxidants in CF and the importance of their balance in effecting oxidative or reductive stress, we will review the determinants of redox balance in the blood, lumen, and cellular compartments. From the perspective of methodological application, we will focus on the approaches most often used to study oxidant and antioxidants in CF, including biochemical, proteomic, metabolomic, and lipidomic studies, with a discussion of the few transcriptomic analyses that predict changes in the expression of regulators of redox. Finally, we will discuss the utility of oxidants and antioxidants as biomarkers of disease and the use of antioxidant therapy in CF. PMID:24657650

Ziady, Assem G; Hansen, Jason

2014-07-01

397

Pressure Effects on Two Superconducting Iron-based Families  

Energy Technology Data Exchange (ETDEWEB)

Insight into the mechanism of high-temperature superconductivity can be gained by pressure-dependent studies of structural, thermodynamics and transport data. The role of pressure may be complicated by the level of hydrostaticity. High-pressure studies on two iron-based families of RFeAsO (R = rare-earth metals) and AFe{sub 2}As{sub 2} (A = alkaline-earth metals) are reviewed here.

Safa-Sefat, Athena [ORNL

2011-01-01

398