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Sample records for earth pressure balance

  1. Feasibility study of tar sands conditioning for earth pressure balance tunnelling

    OpenAIRE

    D. Martinelli; Peila, D.; E. Campa

    2015-01-01

    This paper presents the results of laboratory test on the feasibility of soil conditioning for earth pressure balance (EPB) excavation in a tar sand, which is a natural material never studied in this respect. The laboratory test performed is based on a procedure and methods used in previous studies with different types of soils, but for this special complex material, additional tests are also conducted to verify particular properties of the tar sands, such as the tilt test and vane shear test...

  2. Pressure regulation for earth pressure balance control on shield tunneling machine by using adaptive robust control

    Science.gov (United States)

    Xie, Haibo; Liu, Zhibin; Yang, Huayong

    2016-04-01

    Most current studies about shield tunneling machine focus on the construction safety and tunnel structure stability during the excavation. Behaviors of the machine itself are also studied, like some tracking control of the machine. Yet, few works concern about the hydraulic components, especially the pressure and flow rate regulation components. This research focuses on pressure control strategies by using proportional pressure relief valve, which is widely applied on typical shield tunneling machines. Modeling of a commercial pressure relief valve is done. The modeling centers on the main valve, because the dynamic performance is determined by the main valve. To validate such modeling, a frequency-experiment result of the pressure relief valve, whose bandwidth is about 3 Hz, is presented as comparison. The modeling and the frequency experimental result show that it is reasonable to regard the pressure relief valve as a second-order system with two low corner frequencies. PID control, dead band compensation control and adaptive robust control (ARC) are proposed and simulation results are presented. For the ARC, implements by using first order approximation and second order approximation are presented. The simulation results show that the second order approximation implement with ARC can track 4 Hz sine signal very well, and the two ARC simulation errors are within 0.2 MPa. Finally, experiment results of dead band compensation control and adaptive robust control are given. The results show that dead band compensation had about 30° phase lag and about 20% off of the amplitude attenuation. ARC is tracking with little phase lag and almost no amplitude attenuation. In this research, ARC has been tested on a pressure relief valve. It is able to improve the valve's dynamic performances greatly, and it is capable of the pressure control of shield machine excavation.

  3. Earth Pressure on Tunnel Crown

    DEFF Research Database (Denmark)

    Andersen, Lars

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

  4. Sunspot geometry and pressure balance

    International Nuclear Information System (INIS)

    Measurements on magnetic canopies extending from sunspots show that, at the outer penumbral edge, heights of the bases are independent of sunspot diameter and average 180 km. This places a lower limit on the outer penumbral base; with an assumed thickness of 250 km, the top is approx. equal to 430 km above z = 0(tausub(c) = 1) in the photosphere. Chistyakov's (1962) observations require the penumbral surface to be convex in radial section. The Wilson depression, able thus to be found only from limb-side penumbras, is 1360 km from his selected measurements. Averaged over all regular sunspots without special selection, this drops to 1040 km. Thus tausup(*) = 1 in umbras lies around z = -610 km. Magnetic field-strength measurements relate probably to tausup(*) approx. equal to 0.02, some 160 km higher, where z approx. equal to -450 km. The magnetic pressure of the typical 3250 G sunspot field would support the external-axial gas-pressure difference at z = -330 km, the difference of 120 km lying well within the uncertainties. Tension forces, commonly invoked to achieve pressure balance, do not exceed the uncertainties of measurement. Beyond the sunspot, the base of the sunspot field rises only slowly over at least 16000 km horizontally, whereas Beckers (1963) found the inclination of Hα superpenumbral fibrils to be some 130. These results are nicely compatible since the field angle is typically of this magnitude at the minimum heights where Hα fibrils will be observed, say 1400 km. (orig.)

  5. Rare-Earth Economics: The Balance Problem

    Science.gov (United States)

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

    2013-07-01

    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.

  6. Pressure balance equilibria in the Rotamak

    International Nuclear Information System (INIS)

    It is shown that the steady phase in the operation of the Rotamak is well described by the assumption that the plasma is in an averaged magnetohydrodynamic pressure balance situation and that, using a model based on this assumption, self-consistency imposes conditions relating the temperature and density of the plasma to the steady components of the internal magnetic fields

  7. Seismic induced earth pressures in buried vaults

    International Nuclear Information System (INIS)

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

  8. Dynamic active earth pressure on retaining structures

    Indian Academy of Sciences (India)

    Deepankar Choudhury; Santiram Chatterjee

    2006-12-01

    Earth-retaining structures constitute an important topic of research in civil engineering, more so under earthquake conditions. For the analysis and design of retaining walls in earthquake-prone zones, accurate estimation of dynamic earth pressures is very important. Conventional methods either use pseudo-static approaches of analysis even for dynamic cases or a simple single-degree of freedom model for the retaining wall–soil system. In this paper, a simplified two-degree of freedom mass–spring–dashpot (2-DOF) dynamic model has been proposed to estimate the active earth pressure at the back of the retaining walls for translation modes of wall movement under seismic conditions. The horizontal zone of influence on dynamic earth force on the wall is estimated. Results in terms of displacement, velocity and acceleration-time history are presented for some typical cases, which show the final movement of the wall in terms of wall height, which is required for the design. The non-dimensional design chart proposed in the present study can be used to compute the total dynamic earth force on the wall under different input ground motion and backfill conditions. Finally, the results obtained have been compared with those of the available Scott model and the merits of the present results have been discussed.

  9. 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

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

    CERN Document Server

    Aboumoussa, Walid

    2014-01-01

    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....

  11. Pressure-temperature Phase Diagram of the Earth

    OpenAIRE

    Jones, Eriita; Lineweaver, Charles

    2010-01-01

    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 maximum possible ext...

  12. Earth pressures against- and stability of retaining structures

    OpenAIRE

    Sigurur Mr Valsson 1982

    2011-01-01

    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 properties ...

  13. Accurate determination of equilibrium state between two pressure balances using a pressure transducer

    Science.gov (United States)

    Kobata, Tokihiko; Olson, Douglas A.

    2005-12-01

    To determine an equilibrium state between two pressure balances accurately, the measurement method using a precise pressure transducer and two air-operated constant volume valves (CVV) is proposed in this paper. The advantages of the proposed method are as follows: (1) by the usage of two air-operated CVV, the pressure generated by the pressure balance can be connected and disconnected quickly to the transducer without volume change in the hydraulic circuit or heat transfer from the operator, (2) by managing the time intervals between measurements equally, the method proposed can compensate for the effect of the drift component in the successive values measured by the transducer used and (3) the short time stability of the pressure generated by each pressure balance used can be evaluated quantitatively at each pressure. From the measurement results, it was revealed that the equilibrium state could be determined accurately using the method proposed, and the differences between this method and the conventional fall-rate method were sufficiently small.

  14. Pressure and energy balance of the cool corona over sunspots

    International Nuclear Information System (INIS)

    We study the extreme-ultraviolet (EUV) emission of the 22 largest sunspots observed with the ATM SO55 spectrometer. From their time behavior we infer that the pressure and energy balance of the cool corona over these spots is in a steady state. A straightforward analysis of the resolvable temperature structure over several spots shows that conduction across the field lines from the hot corona is of no importance to the energy balance to the cool magnetic loops extending from the umbrae. Also, directly measured radiative losses along the legs of the loops are too large to be entirely balanced by thermal conduction from a heat source located high in the loop. We conclude that a heat input of about 10-4 ergs cm-3 s-1 is required along the full length of the loop, and is largest off the loop axis. The material cannot be supported at the observed heights either hydrostatically or magnetohydrostatically, or by turbulent motions. Taken together, the pressure and energy balance of the cool loops is most simply understood if coronal material is flowing across field lines at the top of the loops and falling downward along both sides under gravity. This analysis suggests that strong magnetic fields tend to inhibit dissipation of mechanical energy in the corona. We speculate that the corona is heated by transfer of mechanical energy across the very thin transition region immediately over network cell interiors. The magnetic fields of the network, active regions, and filaments simply provide a heat sink on which the hot corona can cool and lose buoyancy. The plasma radiates powerfully in the temperature range 1046 as it subsequently crosses field lines, and falls toward the photosphere, perhaps liberating kinetic energy as ''splashes'' which eject spicules at the magnetic foot points

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

    Energy Technology Data Exchange (ETDEWEB)

    Sorin Zaharia; C.Z. Cheng

    2002-06-18

    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.

  16. 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

  17. Physical Limitations of Empirical Field Models: Force Balance and Plasma Pressure; TOPICAL

    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(del)(sup 2)P=(del)(centerdot) (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

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

    Science.gov (United States)

    Sherman, D

    1991-09-01

    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

  19. Earth Pressure Model with Curved Slip Surfaces by AIM

    Czech Academy of Sciences Publication Activity Database

    Koudelka, Petr

    Rotterdam : A.A.Balkema, 1999 - (Fujita, F.), s. 377-382 [Conf. of Geotechnical Aspects of Underground Construction in Soft Ground. Tokyo (JP), 07.07.1999-10.07.1999] R&D Projects: GA ČR GA103/98/0632 Keywords : Earth (lateral) pressure * apriori integration method * shear surface * slip surface * minimization Subject RIV: JM - Building Engineering

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

    Directory of Open Access Journals (Sweden)

    J. Horabik

    2007-03-01

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

  1. Pressure-temperature Phase Diagram of the Earth

    CERN Document Server

    Jones, Eriita

    2010-01-01

    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 maximum possible extent of the terrestrial biosphere. The intersection of liquid water and terrestrial phase space indicates that the deepest liquid water environments in the lithosphere occur at a depth of ~ 75 km. 3.5 % of the volume of the Earth is above 75 km depth. Considering the 3.5 % of the volume of the Earth where liquid water exists, ~ 12% of this volume is inhabited by life while the remaining ~ 88% is uninhabited. This is distinct from the fraction of the volume of liquid water occupied by life. We find that at least 1% of t...

  2. 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

  3. Precariousness and hazard of lateral earth pressure theory

    Czech Academy of Sciences Publication Activity Database

    Koudelka, Petr

    Reston : American Society of Civil Engineers, 2014 - (Beer, M.; Au, S.; Hall, J.), s. 2765-2779 ISBN 978-0-7844-1360-9. [International Conference on vulnerability and risk analysis and management /2./. Liverpool (GB), 13.07.2014-16.07.2014] Institutional support: RVO:68378297 Keywords : earth pressure * EUROCODE 7-1 * soils Subject RIV: JM - Building Engineering http://ascelibrary.org/doi/abs/10.1061/9780784413609.279

  4. Water-Energy balance in pressure irrigation systems

    Science.gov (United States)

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

    2013-04-01

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

  5. Phase transitions in rare earth tellurides under pressure

    International Nuclear Information System (INIS)

    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 (R3+) 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 (R2+) 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 R2+ → R3+ 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. (paper)

  6. High pressure behaviour of heavy rare earth antimonides

    International Nuclear Information System (INIS)

    We have investigated theoretically the high-pressure structural phase transition and cohesive properties of two heavy rare earth mono anyimonides (LnSb; Ln = Dy and Lu) by using two body interionic potential with necessary modifications to include the effect of Coulomb screening by the delocalized 4f electrons of the RE ion. The peculiar properties of these compounds have been interpreted in terms of the hybridization of f electrons with the conduction band. The calculated compression curves and the values of high-pressure behaviour have been discussed and compared with the experimental results. These compounds exhibits first order crystallographic phase transition from their NaCl (B1) phase to CsCl (B2) phase at 23.6 GPa and 25.4 GPa respectively. At phase transition the % volume collapse for both the compounds are little higher than the measured ones. The NaCl phase possesses lower energy than CsCl phase and stable at ambient pressure. The bulk moduli of LnSb compounds are obtained from the P-V curve fitted by the Birch equation of state. We also calculated the Ln-Ln distance as a function of pressure. (author)

  7. THE HABITABLE ZONE OF EARTH-LIKE PLANETS WITH DIFFERENT LEVELS OF ATMOSPHERIC PRESSURE

    International Nuclear Information System (INIS)

    As a contribution to the study of the habitability of extrasolar planets, we implemented a one-dimensional energy balance model (EBM), the simplest seasonal model of planetary climate, with new prescriptions for most physical quantities. Here we apply our EBM to investigate the surface habitability of planets with an Earth-like atmospheric composition but different levels of surface pressure. The habitability, defined as the mean fraction of the planet's surface on which liquid water could exist, is estimated from the pressure-dependent liquid water temperature range, taking into account seasonal and latitudinal variations of surface temperature. By running several thousands of EBM simulations we generated a map of the habitable zone (HZ) in the plane of the orbital semi-major axis, a, and surface pressure, p, for planets in circular orbits around a Sun-like star. As pressure increases, the HZ becomes broader, with an increase of 0.25 AU in its radial extent from p = 1/3 to 3 bar. At low pressure, the habitability is low and varies with a; at high pressure, the habitability is high and relatively constant inside the HZ. We interpret these results in terms of the pressure dependence of the greenhouse effect, the efficiency of horizontal heat transport, and the extent of the liquid water temperature range. Within the limits discussed in the paper, the results can be extended to planets in eccentric orbits around non-solar-type stars. The main characteristics of the pressure-dependent HZ are modestly affected by variations of planetary properties, particularly at high pressure.

  8. THE HABITABLE ZONE OF EARTH-LIKE PLANETS WITH DIFFERENT LEVELS OF ATMOSPHERIC PRESSURE

    Energy Technology Data Exchange (ETDEWEB)

    Vladilo, Giovanni; Murante, Giuseppe; Silva, Laura [INAF-Trieste Astronomical Observatory, Trieste (Italy); Provenzale, Antonello [Institute of Atmospheric Sciences and Climate-CNR, Torino (Italy); Ferri, Gaia; Ragazzini, Gregorio, E-mail: vladilo@oats.inaf.it [Department of Physics, University of Trieste, Trieste (Italy)

    2013-04-10

    As a contribution to the study of the habitability of extrasolar planets, we implemented a one-dimensional energy balance model (EBM), the simplest seasonal model of planetary climate, with new prescriptions for most physical quantities. Here we apply our EBM to investigate the surface habitability of planets with an Earth-like atmospheric composition but different levels of surface pressure. The habitability, defined as the mean fraction of the planet's surface on which liquid water could exist, is estimated from the pressure-dependent liquid water temperature range, taking into account seasonal and latitudinal variations of surface temperature. By running several thousands of EBM simulations we generated a map of the habitable zone (HZ) in the plane of the orbital semi-major axis, a, and surface pressure, p, for planets in circular orbits around a Sun-like star. As pressure increases, the HZ becomes broader, with an increase of 0.25 AU in its radial extent from p = 1/3 to 3 bar. At low pressure, the habitability is low and varies with a; at high pressure, the habitability is high and relatively constant inside the HZ. We interpret these results in terms of the pressure dependence of the greenhouse effect, the efficiency of horizontal heat transport, and the extent of the liquid water temperature range. Within the limits discussed in the paper, the results can be extended to planets in eccentric orbits around non-solar-type stars. The main characteristics of the pressure-dependent HZ are modestly affected by variations of planetary properties, particularly at high pressure.

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

    CERN Document Server

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

    2013-01-01

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

  10. High pressure behaviour of heavy rare earth mono antimonides

    International Nuclear Information System (INIS)

    We have investigated theoretically the high-pressure structural phase transition and cohesive properties of two heavy rare earth mono antimonides (RESb; RE = Dy and Lu) by using two body interionic potential with necessary modifications to include the effect of Coulomb screening by the delocalized 4f electrons of the RE ion. The peculiar properties of these compounds have been interpreted in terms of the hybridization of f electrons with the conduction band and strong mixing of f states of RE ion with the p orbital of neighboring pnictogen ion. These compounds exhibit first order crystallographic phase transition from their NaCl (B1) phase to CsCl (B2) phase at 23.6 GPa and 25.4 GPa respectively. The bulk modulii of RESb compounds are obtained from the P-V curve fitted by the Birch equation of state. We also calculated the RE-RE distance as a function of pressure. Elastic properties of these compounds have also been studied and their second order elastic constants are calculated.

  11. High pressure behaviour of heavy rare earth mono antimonides

    Energy Technology Data Exchange (ETDEWEB)

    Pagare, Gitanjali [Department of Physics, Govt. M.L.B. Girls P.G. College, Bhopal 462 002 (India); Sen, Deepti [Govt. Girls College, Raisen (India); Srivastava, Vipul; Sanyal, S P, E-mail: gita_pagare@yahoo.co.i [Condensed Matter Physics Lab, Department of Physics, Barkatullah University Bhopal 462 026 (India)

    2010-03-01

    We have investigated theoretically the high-pressure structural phase transition and cohesive properties of two heavy rare earth mono antimonides (RESb; RE = Dy and Lu) by using two body interionic potential with necessary modifications to include the effect of Coulomb screening by the delocalized 4f electrons of the RE ion. The peculiar properties of these compounds have been interpreted in terms of the hybridization of f electrons with the conduction band and strong mixing of f states of RE ion with the p orbital of neighboring pnictogen ion. These compounds exhibit first order crystallographic phase transition from their NaCl (B{sub 1}) phase to CsCl (B{sub 2}) phase at 23.6 GPa and 25.4 GPa respectively. The bulk modulii of RESb compounds are obtained from the P-V curve fitted by the Birch equation of state. We also calculated the RE-RE distance as a function of pressure. Elastic properties of these compounds have also been studied and their second order elastic constants are calculated.

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

    Directory of Open Access Journals (Sweden)

    J. P. O'Kane

    2003-01-01

    Full Text Available An honest declaration of the error in a mass, momentum or energy balance, ε, simply raises the question of its acceptability: 'At what value of ε is the attempted balance to be rejected?' Answering this question requires a reference quantity against which to compare ε. 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

  13. Regional earth-atmosphere energy balance estimates based on assimilations with a GCM

    Science.gov (United States)

    Alexander, Michael A.; Schubert, Siegfried D.

    1990-01-01

    The Oort and Vonder Haar (1976) column-budget technique is presently used to evaluate the physical consistency and accuracy of regional earth-atmosphere energy balance estimates for (1) atmospheric budget terms, (2) net radiation at the top of the atmosphere, and (3) time tendency and flux divergence of energy, for Special Observing Periods of the FGGE year. It is found that, during winter, the midlatitude oceans supply large quantities of energy to the overlying atmosphere, which then transports the energy to the continental heat-sinks; the energy flows in the opposite direction during summer.

  14. Education for a Healthy Body Weight: Helping Adolescents Balance the Cultural Pressure for Thinness.

    Science.gov (United States)

    Collins, M. Elizabeth

    1988-01-01

    The article examines cultural pressure for extreme thinness in the United States and its impact as a possible predisposing factor for developing eating disorders among adolescent females. Preventive strategies are recommended to help adolescents balance this pressure and their own desire for attractiveness within the larger context of good health.…

  15. Seismic Earth Pressure Development in Sheet Pile Retaining Walls: A Numerical Study

    CERN Document Server

    Rajeev, P; Sivakugan, N

    2015-01-01

    The design of retaining walls requires the complete knowledge of the earth pressure distribution behind the wall. Due to the complex soil-structure effect, the estimation of earth pressure is not an easy task; even in the static case. The problem becomes even more complex for the dynamic (i.e., seismic) analysis and design of retaining walls. Several earth pressure models have been developed over the years to integrate the dynamic earth pressure with the static earth pressure and to improve the design of retaining wall in seismic regions. Among all the models, MononobeOkabe (M-O) method is commonly used to estimate the magnitude of seismic earth pressures in retaining walls and is adopted in design practices around the world (e.g., EuroCode and Australian Standards). However, the M-O method has several drawbacks and does not provide reliable estimate of the earth pressure in many instances. This study investigates the accuracy of the M-O method to predict the dynamic earth pressure in sheet pile wall. A 2D pl...

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

    Science.gov (United States)

    Wild, Martin; Liepert, Beate

    2010-06-01

    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 downward thermal radiation during the 20th century, even though direct observational evidence is sparse and restricted to the latter part of the century (Philipona et al 2004, Wild et al 2008). Precipitation records averaged over global land surfaces indicate an overall, albeit not significant, increase in precipitation and intensification of the hydrological cycle over the 20th century (Trenberth et al 2007), in line with the aforementioned surface energy gain from the increased greenhouse gases and related downward thermal radiation. However, the observations show also that precipitation has not simply followed the increasing greenhouse gas forcing, but has undergone strong decadal variations, with extended periods of both increases and decreases. This is evident in figure 1(a), which shows global land precipitation over the 20th century as determined from the Global Historic Climate Network (GHCN; Peterson and Vose 1997, see also Trenberth et al 2007, figure 3.12). An increase in precipitation can be noted in the 1940s, followed by an overall decrease until the mid-1980s, and a renewed increase more recently. Figure 1 Figure 1. Observed terrestrial precipitation anomalies (a) and the longest observational surface solar radiation record measured in Stockholm (b) covering the period 1923-2000 (annual means). The 11-year running means are given in blue. Precipitation data from GHCN, radiation data from GEBA. However, not only greenhouse-gas-induced thermal radiation changes, but also solar radiation, as a result of changes in the atmospheric transmission, can alter the surface radiation balance and thus the amount of energy available to drive the hydrological cycle. Solar forcings may be even more efficient in modifying the intensity of the hydrological cycle than thermal forcings, as indicated by a higher hydrological sensitivity (e.g., Allen and Ingram 2002, Liepert et al 2004). The hydrological sensitivity, defined as change of precipitation per unit temperature change, is found to be 2-3 times larger under solar forcings than under thermal forcings (Liepert et al 2004, Andrews et al 2009). This is related to the fact that solar forcings apply at the surface directly because of the high solar transparency of the atmosphere compared to thermal radiation. Solar forcings thus effectively alter the surface radiation balance and the associated imbalance between the surface and atmospheric energy contents, which needs to be compensated for by convective fluxes and related evaporation/precipitation. Greenhouse-gas-induced thermal forcings, on the other hand, heat the atmosphere directly through radiative absorption and the surface indirectly through downward thermal radiation. Thermal forcings are therefore less effective in strengthening the imbalance between the surface and atmospheric energy contents. Hence the required changes in the compensational convective fluxes and associated evaporation/precipitation are smaller (equation (4) in Liepert and Previdi 2009). The different effects of solar and thermal forcings become particularly evident in the direct (fast) response of the hydrological cycle to them, while the subsequent longer-term response of the hydrological cycle, including all feedbacks induced by these forcings, is similar between the two forcing mechanisms (Andrews et al 2009, Lambert and Webb 2008). The direct effect of doubling of CO2 concentration reduces the precipitation increase in climate models by about 25% (Lambert and Webb 2008), while such compensational effects do not apply with solar forcings. Recent evidence suggests that the amount of solar radiation incident at the Earth's surface (hereafter referred to as downward solar radiation) has indeed not been stable over time but has undergone significant variations on decadal timescales. This evidence comes from the networks of surface radiation measurements taken around the globe which became operational on a widespread basis during the 1950s. Specifically, the measurements show a predominant decrease in downward solar radiation from the 1950s up to the 1980s (known as 'global dimming') and a partial recovery thereafter at many of the sites (known as 'brightening') (e.g., Gilgen et al 1998, Stanhill and Cohen 2001, Liepert 2002, Wild et al 2005, Wild 2009a). The consecutive downward and upward trends have at least to some extent been attributed to increasing and decreasing air pollution, respectively (Streets et al 2009), apart from the natural inter-decadal variability of cloudiness and volcanic eruptions. The longest observational records show in addition a tendency for an increase in downward solar radiation in the first part of the 20th century ('early brightening'). An illustrative example is given in figure 1(b), which depicts the longest continuous record of downward solar radiation measured in Stockholm. This series, starting in 1923, shows an increase in the 1930s and 1940s, an overall decrease from the 1950s up to the 1980s and a more recent recovery. This evolution is, surprisingly, at least qualitatively similar to the global land precipitation record shown in figure 1(a). Although a comparison of a radiation time series measured at a single station with a global land-averaged precipitation time series is by no means representative, it may illustrate the above point of a potential close link between decadal variations of surface radiation and precipitation. Attempts have been made to infer decadal changes in the surface radiation balance based on both modelling and observational approaches. Liepert et al (2004) analyzed equilibrium experiments with a climate model with greenhouse gas and aerosol concentrations representative for mid-1880s and mid-1980s conditions, respectively. They noted a decrease in absorbed solar radiation at the surface of 3.8 Wm-2 globally, mainly due to the aerosol direct and indirect effects, which are larger than the increased greenhouse effect of 1.9 Wm-2. This resulted in a reduction of net surface radiation of 1.9 Wm-2 globally, and a related spin down of the simulated hydrological cycle. Wild et al (2004), based on observational evidence, estimated that the decrease in downward solar radiation between the 1950s and 1980s may have overcompensated the increase in the greenhouse-gas-induced downward thermal radiation during the same period, thus implying a decrease in the surface radiation balance over this period. This fits well with the overall decrease in global terrestrial precipitation between the 1950s and 1980s seen in figure 1(a). This decrease is on the order of 30-40 mm, which corresponds to roughly 3 Wm-2 latent heat equivalent, and which would imply a similar decrease in surface net radiation. Assuming further a decreasing net surface thermal cooling of -1 Wm-2 over this period (Wild et al 2004), this would require an overall decline of about 4 Wm-2 in surface solar radiation to balance it, which is not unrealistic. Since the 1980s, however, there are indications that downward solar radiation overall has recovered and contributed to the increase in the radiative imbalance at the surface, which had increased already due to the increasing downward thermal radiation (Wild et al 2008, see also figure 1(b). This increase in the surface radiation balance, estimated at 2 Wm-2 decade-1 in Wild et al (2008), fits the observational evidence for a recent increase in terrestrial precipitation and associated intensification of the hydrological cycle (figure 1(a)). Improved knowledge of variations of the components of the surface radiation balance is therefore a key to our understanding of past, present and future variations in the intensity of the hydrological cycle. Surface radiation balance and the hydrological cycle in climate models A number of recent studies have pointed out that climate models driven with all known historical forcings simulate smaller changes in precipitation than observed over recent decades (Zhang et al 2007, Wentz et al 2007, Allan and Soden 2007, Liepert and Previdi 2009, Wild et al 2008, Wild 2009a), and may underestimate the increase in precipitation extremes with global warming (Allan and Soden 2008). For the present study, in figure 2 we compare precipitation changes during the 20th century over land surfaces as observed (blue lines, equivalent to figure 1(a)) and simulated by 18 individual coupled atmosphere-ocean models (CMIP3 models) used in the IPCC-AR4 report (in red). Shown are annual anomalies with respect to the 20th century means (dashed lines) as well as superimposed 11-year running means (solid lines) that highlight the decadal variations in both models and observations. None of the models captures the observed decadal variations during the 20th century. Particularly, none of the models qualitatively reproduces the sequence of increase in the 1930s/1940s, decrease from 1950s to the 1980s and renewed increase to 2000, and the correlations between observations and models are insignificant. Standard deviations of the 11-year running means, indicative of the amplitude of decadal variations in the 20th century annual precipitation, amount to 10.7 mm in the GHNC observations and 5.0 mm on average in the models (with a range from 2.6 mm to 10.6 mm). The closest standard deviation to the observations with 10.6 mm is found in the miroc_medres model simulation; however this simulation does not reproduce the main temporal characteristics of the observed time series either (figure 2). Thus, none of the models is capable of simulating the full extent and temporal evolution of decadal variations in 20th century terrestrial precipitation (see also Liepert and Previdi 2009). Here we argue that, among other possibilities, inadequacies in the simulation of surface radiation balance may contribute to the poor simulation of decadal variations in precipitation during the 20th century seen in figure 2. A closer lookat the simulated evolution of the radiation balance over land surfaces during the 20th century seems to confirm this. Specifically, only half of the models qualitatively reproduce the decrease in the terrestrial surface radiation balance between the 1950s and 1980s and the subsequent recovery as indicated in estimates based on observations. Quantitatively, from 1950 to 1985, the linear change in the model-calculated surface radiation balance is on average almost zero, as opposed to the observational evidence for declining surface radiation balance over this period (Wild et al 2004). Over the period 1985-2000, the multi-model mean amounts to an increase of 0.22 Wm-2 decade-1 (with a range from -0.10 to 0.57 Wm-2 decade-1, which is an order of magnitude smaller than for example the estimate given in Wild et al (2008). Figure 2 Figure 2. Terrestrial precipitation anomalies during the 20th century as observed (in blue) and simulated by various models used in the IPCC 4th assessment report and in the Coupled Model Intercomparison Project (CMIP3) (in red). Annual mean time series given as dashed lines, 11-year running means as solid lines. Reference period is the entire 20th century. Annual precipitation observations from GHCN (Peterson and Vose 1997), units mm. Truly global observational estimates of precipitation changes (covering both land and oceans) exist only since 1987 with the advent of satellite data from the Special Sensor Microwave Imager (SSM/I). Based on these observations, Wentz et al (2007) determined an increase in global mean precipitation of 13.2 +/- 4.8 mm yr-1 decade-1 over the period 1987-2006. To induce such an increase, which corresponds to a latent heat release of approximately 1 Wm-2 per decade, an increase in the globally averaged surface radiation balance of at least the same amount would be required accordingly. We obtained this estimate under the assumption of (1) an unchanged sensible heat flux and (2) an unchanged top of atmosphere radiation balance and corresponding surface heat uptake by the ocean and landmasses, so that globally the change in surface net radiation is balanced by the change in latent heat flux. Regarding assumption (1), the global mean sensible heat flux is an order of magnitude smaller than the latent heat flux, and therefore even large relative changes in sensible heating would be small in absolute terms. Assumption (2) is a conservative assumption and can be considered an upper limit because ocean and land heat uptake has likely subtracted a portion of the radiative energy available for evaporation (see, e.g., Hansen et al 2005) over recent decades. Therefore, if the Wentz et al (2007) estimated precipitation increase is unbiased, this would likely require a global mean surface radiation increase of more than 1 Wm-2 per decade (cf also the estimated 2 Wm-2 per decade increase in surface net radiation over land surfaces in Wild et al (2008)). Current climate models, on the other hand, show a much smaller average increase of less than 0.3 Wm-2 per decade. The underestimation of decadal scale variations in downward solar radiation and a lack of dimming and brightening in the models (Romanou et al 2007, Bodas-Salcedo et al 2008, Wild 2009b, Ruckstuhl and Norris 2009) could have affected the simulations of the surface radiation balance. While the response to the gradually increasing greenhouse gases in the thermal component of the surface energy balance is well understood and adequately simulated, much more uncertainties are apparent in the solar component. Since the hydrological cycle may respond particularly sensitive to non-homogeneous short-living types of solar forcings such as aerosols (see discussion above), the identification of the origins of the uncertainties in the solar forcings is of primary importance for predicting future changes. Uncertainties may be related to weaknesses in three areas: (1) Deficiencies in the parameterization of the relevant processes: aerosol-cloud interactions are still poorly understood and related model representations are subject to considerable uncertainties or entirely neglected. Note that only few models include the effects of aerosols on clouds, which dominate the hydrological response as shown in Romanou et al (2007). Furthermore, many models only consider the temporal variations in scattering sulphur aerosol and neglect changes in other aerosol types such as absorbing black carbon or desert dust, which would enhance the degree of freedom of aerosol-cloud interactions and change the stability of the atmosphere. (2) Uncertainties in the highly variable spatial and temporal distributions of global aerosol fields used in the 20th century simulations as e.g. shown by Ruckstuhl and Norris (2009). Also, most models still prescribe fixed spatial aerosol burdens in the atmosphere, rather than aerosol and aerosol precursor emission fields, which could enhance the degree of freedom of the global aerosol system. (3) Shortcomings in the representation of the natural variability in atmosphere/ocean exchanges of energy and water that result in variations of convection and consequently in cloudiness and humidity. For example state-of-the-art climate models do not realistically reproduce decadal variations in the ocean atmosphere system such as Pacific Decadal Oscillation (PDO), Atlantic Multidecadal Oscillation (AMO) or El Nino-Southern Oscillation (ENSO) that may have significant effects. Conclusions To summarize, we emphasize the prominent role of the surface radiation balance as a key determinant of the intensity of the global hydrological cycle. There are indications that the surface radiation balance underwent significant decadal variations during the 20th century, which are reflected in the variations of the intensity of the global hydrological cycle. The current generation of climate models does not show such strong variability in either of these quantities. Here we point to the inadequate representation of surface solar dimming and brightening as a potential cause of these model deficiencies. This is further supported by the recent evidence that solar forcings are more effective in altering the intensity of the global hydrological cycle than their thermal (greenhouse-gas-forced) counterparts. Improved knowledge of variations of the components of the surface radiation balance as well as their underlying forcing factors are therefore key to our understanding of past, present and future variations in the intensity of the hydrological cycle. The recent implementation of advanced space-borne and surface-based monitoring systems should allow for more rigorous constraints of the radiative drivers behind the hydrological cycle. Together with improved modelling capabilities, including sophisticated interactive aerosol and cloud microphysics schemes, these advances should result in more realistic simulations and predictions of the intensity of the hydrological cycle in the near future. Acknowledgements Particular thanks go to Professor Christoph Schär for his valuable input to the manuscript and for his support. Richard Allan's comments on the manuscript were highly appreciated. This study is part of the National Centre for Competence in Climate Research (NCCR Climate) project HYCLIM (Intensification of the water cycle: scenarios, processes and extremes) supported by the Swiss National Science Foundation, and was further sponsored by National Aeronautics and Space Agency Modeling Analysis and Prediction Program NASA-MAP grant NNX09AV16G. We acknowledge the international modeling groups for providing their data for analysis, the Program for Climate Model Diagnosis and Intercomparison (PCMDI) for collecting and archiving the model data, the JSC/CLIVAR Working Group on Coupled Modelling (WGCM) and their Coupled Model Intercomparison Project (CMIP) and Climate Simulation Panel for organizing the model data analysis activity, and the IPCC WG1 TSU for technical support. The IPCC Data Archive at Lawrence Livermore National Laboratory is supported by the Office of Science, US Department of Energy. References Allan R P 2007 Improved simulation of water vapour and clear-sky radiation using 24-hour forecasts from ERA40 Tellus A 59 336-43 Allan R P and Soden B J 2007 Large discrepancy between observed and simulated precipitation trends Geophys. Res. Lett. 34 L18705 Allan R P and Soden B J 2008 Precipitation extremes and the amplification of atmospheric warming Science 321 1481-4 Allen M R and Ingram W 2002 Constraints on future changes in climate and the hydrologic cycle Nature 419 224-32 Andrews T, Forster P M and Gregory J M 2009 A surface energy perspective on climate change J. Climate 22 2557-70 Baumgartner A and Reichel E 1975 The World Water Balance: Mean Annual Global, Continental and Maritime Precipitation, Evaporation and Runoff (Amsterdam: Elsevier) 179 pp Bodas-Salcedo A, Ringer M A and Jones A 2008 Evaluation of the surface radiation budget in the atmospheric component of the Hadley Centre Global Environmental Model (HadGEM1) J. Climate 21 4723-48 Gilgen H, Wild M and Ohmura A 1998 Means and trends of shortwave irradiance at the surface estimated from GEBA J. Climate 11 2042-61 Hansen J et al 2005 Earth's energy imbalance: confirmation and implications Science 308 1431-5 IPCC 2007 Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change ed S Solomon, D Qin, M Manning, Z Chen, M Marquis, K B Averyt, M Tignor and H L Miller (Cambridge: Cambridge University Press) 996 pp Jonkman S N 2005 Global perspectives on loss of human life caused by floods Natural Hazards 34 151-75 Lambert F H and Webb M J 2008 Dependency of global mean precipitation on surface temperature Geophys. Res. Lett. 35 L16706 Liepert B G 2002 Observed reductions of surface solar radiation at sites in the United States and worldwide from 1961 to 1990 Geophy. Res. Lett. 29 1421 Liepert B G 2010 The physical concept of climate forcing Wiley Interdisciplinary Reviews—Climate Change submitted Liepert B G, Feichter J, Lohmann U and Roeckner E 2004 Can aerosols spin down the water cycle in a warmer and moister world? Geophys. Res. Lett. 31 L06207 Liepert B G and Previdi M 2009 Do models and observations disagree on the rainfall response to global warming? J. Climate 22 3156-66 Ohmura A and Wild M 2002 Is the hydrological cycle accelerating? Science 298 1345-6 Ramanathan V, Crutzen P J, Kiehl J T and Rosenfeld D 2001 Aerosol, climate and the hydrological cycle Science 294 2119-24 Romanou A, Liepert B, Schmidt G A, Rossow W B, Ruedy R A and Zhang Y 2007 20th century changes in surface solar irradiance in simulations and observations Geophys. Res. Lett. 34 L05713 Peterson T C and Vose R S 1997 An overview of the Global Historical Climatology Network temperature database Bull. Am. Meteorol. Soc. 78 2837-49 Philipona R, Dürr B, Marty C, Ohmura A and Wild M 2004 Radiative forcing—measured at Earth's surface—corroborate the increasing greenhouse effect Geophys. Res. Lett. 31 L03202 Richter I and Xie S-P 2008 Muted precipitation increase in global warming simulations: a surface evaporation perspective J. Geophys. Res. 113 D24118 Ruckstuhl C and Norris J 2009 How do aerosol histories affect solar 'dimming' and 'brightening' over Europe? IPCC-AR4 models versus observations J. Geophys. Res. 114 D00D04 Stanhill G and Cohen S 2001 Global dimming: a review of the evidence for a widespread and significant reduction in global radiation Agri. Forest Meteorol. 107 255-78 Streets D G, Yan F, Chin M, Diehl T, Mahowald N, Schultz M, Wild M, Wu Y and Yu C 2009 Discerning human and natural signatures in regional aerosol trends, 1980-2006 J. Geophys. Res. 114 D00D18 Trenberth K E et al 2007 Observations: surface and atmospheric climate change Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change ed S Solomon, D Qin, M Manning, Z Chen, M Marquis, K B Averyt, M Tignor and H L Miller (Cambridge: Cambridge University Press) Wentz F J, Ricciardulli L, Hilburn K and Mears C 2007 How much more rain will global warming bring? Science 317 233-35 Wild M 2009a Global dimming and brightening: a review J. Geophys. Res. 114 D00D16 Wild M 2009b How well do IPCC-AR4/CMIP3 climate models simulate global dimming/brightening and twentieth- century daytime and nighttime warming? J. Geophys. Res. 114 D00D11 Wild M, Grieser J and Schär C 2008 Combined surface solar brightening and increasing greenhouse effect support recent intensification of the global land-based hydrological cycle Geophys. Res. Lett. 35 L17706 Wild M, Ohmura A, Gilgen H and Rosenfeld D 2004 On the consistency of trends in radiation and temperature records and implications for the global hydrological cycle Geophys. Res. Lett. 31 L11201 Wild M et al 2005 From dimming to brightening: decadal changes in surface solar radiation Science 308 847-50 Yang F, Kumar A, Schlesinger M E and Wang W 2003 Intensity of hydrological cycles in warmer climates J. Climate 16 2419-23 Zhang X et al 2007 Detection of human influence on twentieth-century precipitation trends Nature 448 461-5

  17. Energy Balance and Power Performance Analysis for Satellite in Low Earth Orbit

    Science.gov (United States)

    Jang, Sung-Soo; Kim, Sung-Hoon; Lee, Sang-Ryool; Choi, Jaeho

    2010-09-01

    The electrical power system (EPS) of Korean satellites in low-earth-orbit is designed to achieve energy balance based on a one-orbit mission scenario. This means that the battery has to be fully charged at the end of a one-orbit mission. To provide the maximum solar array (SA) power generation, the peak power tracking (PPT) method has been developed for a spacecraft power system. The PPT is operated by a software algorithm, which tracks the peak power of the SA and ensures the battery is fully charged in one orbit. The EPS should be designed to avoid the stress of electronics in order to handle the main bus power from the SA power. This paper summarizes the results of energy balance to achieve optimal power sizing and the actual trend analysis of EPS performance in orbit. It describes the results of required power for the satellite operation in the worst power conditions at the end-of-life, the methods and input data used in the energy balance, and the case study of energy balance analyses for the normal operation in orbit. Both 10:35 AM and 10:50 AM crossing times are considered, so the power performance in each case is analyzed with the satellite roll maneuver according to the payload operation concept. In addition, the data transmission to the Korea Ground Station during eclipse is investigated at the local-time-ascending-node of 11:00 AM to assess the greatest battery depth-of-discharge in normal operation.

  18. BALANCE

    Science.gov (United States)

    Carmichael, H.

    1953-01-01

    A torsional-type analytical balance designed to arrive at its equilibrium point more quickly than previous balances is described. In order to prevent external heat sources creating air currents inside the balance casing that would reiard the attainment of equilibrium conditions, a relatively thick casing shaped as an inverted U is placed over the load support arms and the balance beam. This casing is of a metal of good thernnal conductivity characteristics, such as copper or aluminum, in order that heat applied to one portion of the balance is quickly conducted to all other sensitive areas, thus effectively preventing the fornnation of air currents caused by unequal heating of the balance.

  19. Reliability and validity of center of pressure measures for balance assessment in older adults

    Science.gov (United States)

    Li, Zhen; Liang, Yan-Yi; Wang, Lei; Sheng, Jing; Ma, Shao-Jun

    2016-01-01

    [Purpose] This study was conducted to assess the reliability and validity of center of pressure-based parameters for balance assessment. [Subjects and Methods] Two hundred and forty older adults were evaluated using a force platform and the Berg Balance Scale at 1-week intervals. The intra-class correlation coefficient and the Pearson correlation coefficient were used to test reliability and validity respectively. [Results] The reliability of the 12 selected center of pressure measures was satisfactory (intra-class correlation coefficient = 0.75–0.99) and the validity between the parameters and the Berg Balance Scale was moderate to good (r = −0.62 to −0.88). [Conclusion] Center of pressure-based parameters are reliable and valid measures in older adults.

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

    Science.gov (United States)

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

    1995-04-01

    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.

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

    Science.gov (United States)

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

    1995-01-01

    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.

  2. Pressure balance and pressure distribution along the dayside ionopause of Venus

    International Nuclear Information System (INIS)

    The pressure distribution within the magnetic barrier just outside the ionopause of Venus is shown to be similar to expected solar wind pressure variation. The important role of solar wind heating of the subsolar ionosphere and the significant influence of transport processes within the ionosphere at large solar zenith angle on the shape of the venusian ionosphere are examined. It is considered that the model of the subionopause pressure distribution with height and with the solar zenith angle seems to represent reasonably the observed behaviour of ionopause crossings at different solar zenith angle and allows one to obtain an 'instant' profile of the ionopause for given solar wind pressure. (UK)

  3. Seismic earth pressures on flexible cantilever retaining walls with deformable inclusions

    OpenAIRE

    Ozgur L. Ertugrul; TRANDAFIR, Aurelian C.

    2014-01-01

    In this study, the results of 1-g shaking table tests performed on small-scale flexible cantilever wall models retaining composite backfill made of a deformable geofoam inclusion and granular cohesionless material were presented. Two different polystyrene materials were utilized as deformable inclusions. Lateral dynamic earth pressures and wall displacements at different elevations of the retaining wall model were monitored during the tests. The earth pressures and displacements of the retain...

  4. Earth radiation balance as observed and represented in CMIP5 models

    Science.gov (United States)

    Wild, Martin; Folini, Doris; Schr, Christoph; Loeb, Norman; Knig-Langlo, Gert

    2014-05-01

    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. Brnnimann, 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

  5. Pressure-induced changes in the compression mechanism of aluminous perovskite in the Earth's mantle

    Science.gov (United States)

    Brodholt

    2000-10-01

    Although aluminium is the fifth most abundant element in the Earth's mantle, its effect on the physical properties of perovskite, the main mineral phase in the lower mantle, has largely been ignored. It is becoming clear, however, that many properties of MgSiO3 perovskites are remarkably sensitive to small amounts of aluminium. In particular, perovskite with only 5 wt% Al2O3 has a bulk modulus 10% lower than that of the pure magnesian end-member. The increased compressibility may be due to the high concentrations of oxygen vacancies required to balance the charge of the aluminium; if so, this would have important consequences for the mantle, as aluminous perovskites could be weaker, have lower seismic velocities and be hosts for water. To test whether oxygen vacancies exist in aluminous perovskites, I have calculated the compressibility of end-member defect-bearing perovskites using ab initio methods. The results show that perovskites with oxygen vacancies do have significantly greater compressibilities than those without such vacancies. But the results also suggest that oxygen vacancies become unfavourable at high pressures, in which case only the physical properties of the shallow lower mantle would be affected by aluminium-with the deeper mantle retaining properties similar to those of aluminium-free perovskite. PMID:11034208

  6. Balancing

    Science.gov (United States)

    Harteveld, Casper

    At many occasions we are asked to achieve a balance in our lives: when it comes, for example, to work and food. Balancing is crucial in game design as well as many have pointed out. In games with a meaningful purpose, however, balancing is remarkably different. It involves the balancing of three different worlds, the worlds of Reality, Meaning, and Play. From the experience of designing Levee Patroller, I observed that different types of tensions can come into existence that require balancing. It is possible to conceive of within-worlds dilemmas, between-worlds dilemmas, and trilemmas. The first, the within-world dilemmas, only take place within one of the worlds. We can think, for example, of a user interface problem which just relates to the world of Play. The second, the between-worlds dilemmas, have to do with a tension in which two worlds are predominantly involved. Choosing between a cartoon or a realistic style concerns, for instance, a tension between Reality and Play. Finally, the trilemmas are those in which all three worlds play an important role. For each of the types of tensions, I will give in this level a concrete example from the development of Levee Patroller. Although these examples come from just one game, I think the examples can be exemplary for other game development projects as they may represent stereotypical tensions. Therefore, to achieve harmony in any of these forthcoming games, it is worthwhile to study the struggles we had to deal with.

  7. Validating and Calibrating the Nintendo Wii Balance Board to Derive Reliable Center of Pressure Measures

    OpenAIRE

    Julia M. Leach; Martina Mancini; Peterka, Robert J.; Tamara L. Hayes; Horak, Fay B.

    2014-01-01

    The Nintendo Wii balance board (WBB) has generated significant interest in its application as a postural control measurement device in both the clinical and (basic, clinical, and rehabilitation) research domains. Although the WBB has been proposed as an alternative to the “gold standard” laboratory-grade force plate, additional research is necessary before the WBB can be considered a valid and reliable center of pressure (CoP) measurement device. In this study, we used the WBB and a laborator...

  8. Pressure-induced superconducting phase in rare-earth tritellurides (RTe3, R = Gd, Tb, Dy)

    International Nuclear Information System (INIS)

    It has recently been reported that the low-dimensional rare-earth tritellurides RTe3 (R=La-Nd,Sm,Gd-Tm) enter an unidirectional, incommensurate charge-density-wave (CDW) state when cooled below a temperature TCDW1∝ 450-250 K, which decreases with increasing rare earth atomic number, due to the effect of chemical pressure. For the heavier R (i. e.: Dy-Tm), a second CDW appears at TCDW2CDW1, orthogonal to the first one. We have recently found that the application of external pressure induces a superconducting (SC) state in GdTe3, TbTe3 and DyTe3 at low temperatures, coexisting or competing with the two CDWs and the local moment rare-earth magnetism. In this talk, we present the results of experiments we have performed on these materials at high pressure and low temperature, to help develop an understanding of the origin of the superconducting state.

  9. Seismic earth pressures on flexible cantilever retaining walls with deformable inclusions

    Directory of Open Access Journals (Sweden)

    Ozgur L. Ertugrul

    2014-10-01

    Full Text Available In this study, the results of 1-g shaking table tests performed on small-scale flexible cantilever wall models retaining composite backfill made of a deformable geofoam inclusion and granular cohesionless material were presented. Two different polystyrene materials were utilized as deformable inclusions. Lateral dynamic earth pressures and wall displacements at different elevations of the retaining wall model were monitored during the tests. The earth pressures and displacements of the retaining walls with deformable inclusions were compared with those of the models without geofoam inclusions. Comparisons indicated that geofoam panels of low stiffness installed against the retaining wall model affect displacement and dynamic lateral pressure profile along the wall height. Depending on the inclusion characteristics and the wall flexibility, up to 50% reduction in dynamic earth pressures was observed. The efficiency of load and displacement reduction decreased as the flexibility ratio of the wall model increased. On the other hand, dynamic load reduction efficiency of the deformable inclusion increased as the amplitude and frequency ratio of the seismic excitation increased. Relative flexibility of the deformable layer (the thickness and the elastic stiffness of the polystyrene material played an important role in the amount of load reduction. Dynamic earth pressure coefficients were compared with those calculated with an analytical approach. Pressure coefficients calculated with this method were found to be in good agreement with the results of the tests performed on the wall model having low flexibility ratio. It was observed that deformable inclusions reduce residual wall stresses observed at the end of seismic excitation thus contributing to the post-earthquake stability of the retaining wall. The graphs presented within this paper regarding the dynamic earth pressure coefficients versus the wall flexibility and inclusion characteristics may serve for the seismic design of full-scale retaining walls with deformable polystyrene inclusions.

  10. Balancing the books ? a statistical theory of prospective budgets in Earth System science

    OpenAIRE

    O'Kane, J. P.

    2003-01-01

    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...

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

    DEFF Research Database (Denmark)

    Krogsbøll, Anette Susanne; Fuglsang, Leif D

    The influence of wall flexibility on earth pressure, bending moments and failure modes is studied. Numerical models are compared to results from model tests carried out in a geotechnical centrifuge. The back-fill is dry sand and failure is introduced by allowing the wall to rotate around the anch...

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

    DEFF Research Database (Denmark)

    Krogsbll, Anette Susanne; Fuglsang, Leif D

    The influence of wall flexibility on earth pressure, bending moments and failure modes is studied. Numerical models are compared to results from model tests carried out in a geotechnical centrifuge. The back-fill is dry sand and failure is introduced by allowing the wall to rotate around the anchor...

  13. Effect of pressure on the coordination structure of acetate-rare earth complex in water

    International Nuclear Information System (INIS)

    Pressure-induced coordination structural changes of the acetate-rare earth complex in water (LnCl320H2OCH3COOLi) have been investigated using Raman spectroscopy. From the analysis of Raman CC stretching band of acetate ion, the integrated Raman intensity of polymeric chain structure decreases with increasing pressure throughout the rare-earth series. The monodentate ligand appears at around 0.6 GPa in the meddle-heavy rare earth region. We have determined the difference in the partial molar volume (PMV) (?V) among three coordination structures. The rank ordering of the PMV of three coordination structures is as follows: monodentate ligand Polymeric?Bidentate and ?VBidentate?Monodentate become larger with decreasing ionic radius of Ln3+ ion, and theses are probably due to the size effect of Ln3+ ion.

  14. Current long-term negative average annual energy balance of the earth leads to the new little ice age

    Directory of Open Access Journals (Sweden)

    Abdussamatov Habibullo

    2015-01-01

    Full Text Available The average annual decreasing rate of the total solar irradiance (TSI is increasing from the 22-nd to the 23-rd and 24-th cycles, because the Sun since the 1990 is in the phase decline of quasi-bicentennial variation. The portion of the solar energy absorbed by the Earth is decreasing. Decrease in the portion of TSI absorbed by the Earth since 1990 remains uncompensated by the Earth's radiation into space at the previous high level over a time interval determined by the thermal inertia of the Ocean. A long-term negative deviation of the Earth’s average annual energy balance from the equilibrium state is dictating corresponding variations in it’s the energy state. As a result, the Earth will have a negative average annual energy balance also in the future. This will lead to the beginning of the decreasing in the Earth's temperature and of the epoch of the Little Ice Age after the maximum phase of the 24-th solar cycle approximately since the end of 2014. The influence of the consecutive chain of the secondary feedback effects (the increase in the Bond albedo and the decrease in the concentration of greenhouse gases in the atmosphere due to cooling will lead to an additional reduction of the absorbed solar energy and reduce the greenhouse effect. The start of the TSI’s Grand Minimum is anticipated in the solar cycle 27±1 in 2043±11 and the beginning of the phase of deep cooling of the 19th Little Ice Age for the past 7,500 years around 2060±11.

  15. Magnetic Collapse in Transition Metal Oxides at High Pressure: Implications for the Earth

    Science.gov (United States)

    Cohen; Mazin; Isaak

    1997-01-31

    Magnetic collapse in transition metal ions is predicted from first-principles computations at pressures reached in the Earth's lower mantle and core. Magnetic collapse would lead to marked changes in geophysically important properties, such as elasticity and conductivity, and also to different geochemical behavior, such as element partitioning, than estimated by extrapolating low-pressure data, and thus change the understanding of Earth's structure and evolution. Magnetic collapse results from band widening rather than from changes in crystal field splitting under pressure. Seismic anomalies in the outer core and the lowermost mantle may be due to magnetic collapse of ferrous iron, dissolved in iron liquid in the outer core, and in solution in magnesiowustite in the lowermost mantle. PMID:9005849

  16. An Analytical Method for Static Earth Pressure Distribution against Rectangular Shallow Tunnels Using Lateral Deformation

    Directory of Open Access Journals (Sweden)

    Farzad Habibbeygi

    2015-10-01

    Full Text Available Analytical methods for computing the lateral earth pressure against tunnel is vastly used by engineers all over the world. Conventional analytical methods compute the lateral pressure in either active or passive state while the stress state usually falls between these two boundaries in many practical cases. Furthermore, using these boundary coefficients lead to either overestimated or underestimated results in design. Thus, a modified method based on the strain increment theory for calculating the lateral pressure against rectangular tunnels is presented herein to consider the amount of lateral deformation at each depth. First, the results for different values of overburden depth, friction angle and wall mobilized angle are investigated. Then comparative finite element analyses were performed to examine the effectiveness of the method. According to this study, the pressure pattern is completely nonlinear especially at the corners of tunnel lining. In fact, the pressure increases nonlinearly to about three times of the value at top. Lateral earth pressure decreases with the increase of friction angle which is in good agreement with finite element results. Overall, the pressure patterns derived by this method for shallow depths (less than tunnel height are almost the same as those computed by finite element method.

  17. Structural phase transitions of rare earth monophosphides with NaCl-type structure under high pressures

    International Nuclear Information System (INIS)

    Rare earth monophosphides REP (RE=La, Ce, Pr, Nd, Sm, Gd, Tb, Tm and Yb) crystallize in a NaCl-type structure at ambient pressure. Using synchrotron radiation X-ray diffractions of REP have been studied up to about 60 GPa at room temperature. All phosphides are found to undergo structural phase transitions at high pressures. The high pressure phases of LaP, PrP and NdP can be assigned to be a tetragonal structure, which can be seen as the distorted CsCl-type structure. The pressure-induced phase transitions of SmP, GdP, TbP, TmP and YbP occur at around 35, 40, 38, 53 and 51 GPa, respectively. The structure of the high pressure phases is unknown. X-ray diffraction patterns of the compounds with many f-electrons become more complex at high pressure. It is expected that 4f-electrons in rare earth atoms influence the structure of the high pressure phases. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2002-02-01

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

  19. A rightly balanced intellectual property rights regime as a mechanism to enhance commercial earth observation activities

    Science.gov (United States)

    Doldirina, Catherine

    2010-09-01

    Earth observation by satellites is one of the developing sectors of space activities with the growing involvement in private capital or actors. This leads to the question of how efficient legal rules governing this activity are. Copyright law is one of the key fields of law applicable to earth observation activities and is the subject of the present analysis. This paper describes the current state of copyright regulations in different jurisdictions. It also addresses the issue of defining earth observation data for the purpose of applying copyright protection to them. Finally, it analyses whether more or less copyright protection would be beneficial for the commercialisation of the earth observation activities, and the distribution and further use of data they produce. The paper is largely based on my current doctoral research. Draft chapter on file with the author.

  20. 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

  1. 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.

  2. Previously hidden low-energy ions: a better map of near-Earth space and the terrestrial mass balance

    Science.gov (United States)

    Andr, Mats

    2015-12-01

    This is a review of the mass balance of planet Earth, intended also for scientists not usually working with space physics or geophysics. The discussion includes both outflow of ions and neutrals from the ionosphere and upper atmosphere, and the inflow of meteoroids and larger objects. The focus is on ions with energies less than tens of eV originating from the ionosphere. Positive low-energy ions are complicated to detect onboard sunlit spacecraft at higher altitudes, which often become positively charged to several tens of volts. We have invented a technique to observe low-energy ions based on the detection of the wake behind a charged spacecraft in a supersonic ion flow. We find that low-energy ions usually dominate the ion density and the outward flux in large volumes in the magnetosphere. The global outflow is of the order of 1026 ions s1. This is a significant fraction of the total number outflow of particles from Earth, and changes plasma processes in near-Earth space. We compare order of magnitude estimates of the mass outflow and inflow for planet Earth and find that they are similar, at around 1 kg s?1 (30 000 ton yr?1). We briefly discuss atmospheric and ionospheric outflow from other planets and the connection to evolution of extraterrestrial life.

  3. Elastic, thermal and high pressure structural properties of heavy rare earth antimonides

    International Nuclear Information System (INIS)

    Pressure induced structural phase transition of two heavy rare earth antimonides (RESb; RE=Ho, Er) have been studied theoretically by using an inter-ionic potential theory. This method has been found quite satisfactory in the case of pnictides of rare earth and describes the crystal properties in the framework of rigid-ion modal. The long-range Coulomb interaction, short-range repulsive interaction and van der Waals (vdW) interactions are properly incorporated in this theory. These compounds exhibit first order crystallographic phase transition from their NaCl-type structure to CsCl-type structure at 27 GPa and 33.2 GPa, respectively. The bulk moduli of RESb compounds are compared with the experimental values of elastic constants. We have also calculated the Debye temperature by incorporating the elastic constants for both the rare earth antimonides. (author)

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

    International Nuclear Information System (INIS)

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

  5. Experimental and Numerical Modeling of Seismic Earth Pressures on Retaining Walls with Cohesive Backfills

    OpenAIRE

    CANDIA, GABRIEL ALFONSO

    2013-01-01

    Observations from recent earthquakes show that all types of retaining structures with non-liquefiable backfills perform very well and there is limited evidence of damage or failures related to seismic earth pressures. Even retaining structures designed only for static loading have performed well during strong ground motions suggesting that special seismic design provisions may not be required in some cases. The objective of this study was to characterize the seismic interaction of backfill-wa...

  6. Prediction of Seismic Active Earth Pressure Using Curved Failure Surface with Localized Strain

    Directory of Open Access Journals (Sweden)

    Hemanta Hazarika

    2009-01-01

    Full Text Available Problem statement: Correct evaluation of the earth pressure against retaining structure during earthquake is essential for the safe and economic design of geotechnical structures. Progressive deformation in the backfill and the assumed shape of failure wedge affect the calculated values of seismic earth pressures. However, no research until now is available that considers both of these two factors in an analysis. Approach: In this study, a new analytical methodology was proposed that took into the account the progressive failure of the backfill soil as well as the shape of the failure wedge. A new formulation was first established taking the failure plane as the combination of a curved lower part and a straight upper part. The localized deformation of the backfill was accounted for in the formulation by utilizing the mobilized friction angle and the peak friction angle depending on the locations along the failure surface. The proposed methodology was validated by comparing the calculated results with the established experimental results. Calculations were also performed for different types of wall with various backfill inclinations. Results: The developed methodology could predict the seismic active earth pressure against retaining structure with reasonable accuracy. It could also realistically predict the active failure domain in the backfill soil at the high excitation level, as compared to the pseudo-static solution provided by the well-known Mononobe-Okabe method. Conclusion/Recommendations: It was observed that the Mononobe-Okabe method underestimates the seismic active earth pressure and overestimates the domain of failure zone in the backfill, especially under intense seismic excitation. The proposed methodology, therefore, can contribute greatly towards the economic earthquake resistant design of geotechnical structures.

  7. A Plantar-pressure Based Tongue-placed Tactile Biofeedback System for Balance Improvement

    CERN Document Server

    Vuillerme, Nicolas; Pinsault, Nicolas; Fleury, Anthony; Demongeot, Jacques; Payan, Yohan

    2007-01-01

    Maintaining an upright stance represents a complex task, which is achieved by integrating sensory information from the visual, vestibular and somatosensory systems. When one of these sensory inputs becomes unavailable and/or inaccurate and/or unreliable, postural control generally is degraded. One way to solve this problem is to supplement and/or substitute limited/altered/missing sensory information by providing additional sensory information to the central nervous system via an alternative sensory modality. Along these lines, we developed an original biofeedback system [1] whose underlying principle consists in supplying the user with supplementary sensory information related to foot sole pressure distribution through a tongue-placed output device (Tongue Display Unit, "TDU" [2]). The purpose of the present experiment was to assess its effectiveness in improving balance in young healthy adults.

  8. Modeling long-term changes in forested landscapes and their relation to the Earth's energy balance

    Science.gov (United States)

    Shugart, H. H.; Emanuel, W. R.; Solomon, A. M.

    1984-01-01

    The dynamics of the forested parts of the Earth's surface on time scales from decades to centuries are discussed. A set of computer models developed at Oak Ridge National Laboratory and elsewhere are applied as tools. These models simulate a landscape by duplicating the dynamics of growth, death and birth of each tree living on a 0.10 ha element of the landscape. This spatial unit is generally referred to as a gap in the case of the forest models. The models were tested against and applied to a diverse array of forests and appear to provide a reasonable representation for investigating forest-cover dynamics. Because of the climate linkage, one important test is the reconstruction of paleo-landscapes. Detailed reconstructions of changes in vegetation in response to changes in climate are crucial to understanding the association of the Earth's vegetation and climate and the response of the vegetation to climate change.

  9. High pressure μSR studies: rare earths and related materials

    International Nuclear Information System (INIS)

    After a short introduction to μSR with respect to the study of magnetic properties, followed by a brief outline of the principle of the high pressure-low temperature μSR spectrometer installed at the Paul Scherrer Institute, we discuss some measurements on rare earth materials employing this instrument. They are concerned with: (1) The pressure dependence of the spin turning process in ferromagnetic Gd. (2) The volume dependence of the internal magnetic field in the heavy rare earth metals Gd, Dy, and Ho in their ordered magnetic states. (3) The response of the (first order) magnetic transition in the frustrated antiferromagnets of type RMn2 (R = Y,Gd) to pressure. (4) The variation of magnetic parameters with pressure in La2CuO4 (powder sample), the antiferromagnetic parent compound of the high TC superconductors of type La2-x(Sr, Ba)xCuO4. In conclusion a short outlook on further developments is given

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

    International Nuclear Information System (INIS)

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

  11. Test re-test reliability of centre of pressure measures during standing balance in individuals with knee osteoarthritis.

    Science.gov (United States)

    Takacs, Judit; Carpenter, Mark G; Garland, S Jayne; Hunt, Michael A

    2014-01-01

    Assessment of changes in standing balance following an intervention requires accurate measurement of balance parameters. The reliability of centre of pressure measures of balance during single-leg standing has not been reported in individuals with knee osteoarthritis. The purpose of this study was to assess the test re-test reliability of force platform centre of pressure measures during single-leg standing in older adults with knee osteoarthritis. Twenty-five adults with radiographic evidence of knee osteoarthritis performed single-leg standing balance trials on a laboratory-grade force platform on two occasions, no more than 14 days apart. Participants were asked to stand on their more symptomatic limb for three, ten second trials. Centre of pressure measures collected included: standard deviation in the mediolateral and anteroposterior directions, mean path length, velocity, and area. The mean of the three trials was calculated. Intraclass correlation coefficients, standard error of measurement, Bland and Altman plots and the minimum detectable change were calculated. Intraclass correlation coefficients ranged from 0.54 to 0.87, suggesting mixed reliability of measures. Reliability was lowest for the centre of pressure area (intraclass correlation coefficient=0.54), and highest for centre of pressure velocity and path length (intraclass correlation coefficient=0.87 for both). Standard error of measurement values were low for standard deviation in the mediolateral direction and high for centre of pressure area. These results suggest that centre of pressure values, in particular path length and velocity, are appropriate for assessment of standing balance in people with medial knee osteoarthritis. PMID:24746407

  12. The Earth's core composition from high pressure density measurements of liquid iron alloys

    Science.gov (United States)

    Morard, G.; Siebert, J.; Andrault, D.; Guignot, N.; Garbarino, G.; Guyot, F.; Antonangeli, D.

    2013-07-01

    High-pressure, high-temperature in situ X-ray diffraction has been measured in liquid iron alloys (Fe-5 wt% Ni-12 wt% S and Fe-5 wt% Ni-15 wt% Si) up to 94 GPa and 3200 K in laser-heated diamond anvil cells. From the analysis of the X-ray diffuse scattering signal of the metallic liquids, we determined density and bulk modulus of the two liquid alloys. Comparison with a reference Earth model indicates that a core composition containing 6% of sulfur and 2% of silicon by weight would best match the geophysical data. Models with 2.5% of sulfur and 4-5% of silicon are still consistent with geophysical constraints whereas silicon only compositions are not. These results suggest only moderate depletion of sulfur in the bulk Earth.

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

    Science.gov (United States)

    Cordier, Patrick; Amodeo, Jonathan; Carrez, Philippe

    2012-01-12

    Plate tectonics, which shapes the surface of Earth, is the result of solid-state convection in Earth's mantle over billions of years. Simply driven by buoyancy forces, mantle convection is complicated by the nature of the convecting materials, which are not fluids but polycrystalline rocks. Crystalline materials can flow as the result of the motion of defects--point defects, dislocations, grain boundaries and so on. Reproducing in the laboratory the extreme deformation conditions of the mantle is extremely challenging. In particular, experimental strain rates are at least six orders of magnitude larger than in nature. Here we show that the rheology of MgO at the pressure, temperature and strain rates of the mantle is accessible by multiscale numerical modelling starting from first principles and with no adjustable parameters. Our results demonstrate that extremely low strain rates counteract the influence of pressure. In the mantle, MgO deforms in the athermal regime and this leads to a very weak phase. It is only in the lowermost lower mantle that the pressure effect could dominate and that, under the influence of lattice friction, a viscosity of the order of 10(21)-10(22) pascal seconds can be defined for MgO. PMID:22237109

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

    International Nuclear Information System (INIS)

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

  15. Atmospheric pressure forced oceans and their effects on Earth's Rotation: a TOPEX data approach

    Science.gov (United States)

    Dey, N.; Dickman, S. R.

    2014-12-01

    Dey & Dickman [2010] showed (using a theoretical model) that the oceanic response to atmospheric pressure forcing depends on the frequency and spatial pattern of the forcing. We have developed an observational Green's function approach to determine the frequency- and spatially dependent sea-level response using satellite altimetric data. We applied it to 12 years of TOPEX sea-surface height (SSH) observations smoothed over a 4 8 grid at 3 day intervals and corrected for tides, winds, annual signals and secular trends. Wiener filtering, generalized for complex time series, was used to isolate pressure forced SSH within each gridbox. In most of the gridboxes, that SSH, after accounting for the forcing, showed a spatial and spectral dependence - a significant departure from the "inverted barometer" response. The oceanic currents associated with the response were calculated from a spherical harmonic relation between current velocities and SSH [Dickman 1991]. The rotational effects (polar motion and change in Earth's spin rate) of the pressure forced SSH & associated currents - with the pressure forcing accounted for, these are essentially Green's functions - were calculated at specific periods and interpolated to other periods. The rotational effects calculated here are dominated by the pressure-forced SSH and show a strong frequency dependence & significant departures from an inverted barometer excitation. The pressure forced SSH is effective in exciting both prograde & retrograde polar motion at periods of ~ 6 days, and prograde polar motion at periods of 10 - 15 days. Compared to the theoretical approach, our work finds that the prograde component shows higher amplitude and less spatial variability, whereas the other components are ~ similar in amplitude & spatial variability. When these Green's functions are combined with any time span of pressure data, they generate the total excitation for that time span. We will discuss the results for various spans of pressure data.

  16. Implications for Core Formation of the Earth from High Pressure-Temperature Au Partitioning Experiments

    Science.gov (United States)

    Danielson, L. R.; Sharp, T. G.; Hervig, R. L.

    2005-01-01

    Siderophile elements in the Earth.s mantle are depleted relative to chondrites. This is most pronounced for the highly siderophile elements (HSEs), which are approximately 400x lower than chondrites. Also remarkable is the relative chondritic abundances of the HSEs. This signature has been interpreted as representing their sequestration into an iron-rich core during the separation of metal from silicate liquids early in the Earth's history, followed by a late addition of chondritic material. Alternative efforts to explain this trace element signature have centered on element partitioning experiments at varying pressures, temperatures, and compositions (P-T-X). However, first results from experiments conducted at 1 bar did not match the observed mantle abundances, which motivated the model described above, a "late veneer" of chondritic material deposited on the earth and mixed into the upper mantle. Alternatively, the mantle trace element signature could be the result of equilibrium partitioning between metal and silicate in the deep mantle, under P-T-X conditions which are not yet completely identified. An earlier model determined that equilibrium between metal and silicate liquids could occur at a depth of approximately 700 km, 27(plus or minus 6) GPa and approximately 2000 (plus or minus 200) C, based on an extrapolation of partitioning data for a variety of moderately siderophile elements obtained at lower pressures and temperatures. Based on Ni-Co partitioning, the magma ocean may have been as deep as 1450 km. At present, only a small range of possible P-T-X trace element partitioning conditions has been explored, necessitating large extrapolations from experimental to mantle conditions for tests of equilibrium models. Our primary objective was to reduce or remove the additional uncertainty introduced by extrapolation by testing the equilibrium core formation hypothesis at P-T-X conditions appropriate to the mantle.

  17. Numerical investigation of the real and ideal gap profiles in the calculation of the pressure distortion coefficient and piston fall rate of an LNE 200 MPa pressure balance

    OpenAIRE

    WONGTHEP, Padipat; RABAULT, Thierry; NOGUERA, Ricardo; Sarraf, Christophe

    2013-01-01

    This paper aims to investigate, by means of numerical simulation, the effect of gap profiles on the calculation of the pressure distortion coefficient (λ) and the piston fall rate (vf) of two piston-cylinder units used in a Laboratoire National de Métrologie et d'Essais (LNE) 200 MPa pressure balance. The ideal mean gap width between the piston and the cylinder was obtained after measuring the piston fall rate at a low pressure, while the piston radius was obtained from the cross-float experi...

  18. Pressure and strain effects of hexagonal rare-earth manganites: a first-principles study.

    Science.gov (United States)

    Tan, Hengxin; Xu, Changsong; Li, Menglei; Wang, Shanying; Gu, Bing-Lin; Duan, Wenhui

    2016-03-31

    We have investigated the structural, electrical and magnetic properties as well as the phonon modes of hexagonal rare-earth manganites (RMnO3, R  =  Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm and Lu) under chemical pressure, hydrostatic pressure and epitaxial strain by first-principles calculations. The magnetic ground state of RMnO3 is found to have [Formula: see text] magnetic configuration and to be stable under all considered external conditions. In contrast, the K 3 phonon mode, which is the primary order parameter and responsible for the 'improper ferroelectricity', is greatly influenced by pressure and epitaxial strain. Consequently, the electric polarization is enhanced by 56.7% when the chemical pressure increases from R  =  Pr to R  =  Lu. The hydrostatic pressure can also improve the polarization to a certain degree, e.g. by 14.7% from 0 GPa to 40 GPa in LuMnO3. Finally, the dependence of polarization on the epitaxial strain is also given, revealing that the compressive strain could promote the ferroelectricity while tensile strain will suppress it. PMID:26916139

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

    DEFF Research Database (Denmark)

    Krogsbøll, Anette Susanne; Fuglsang, Leif D

    The influence of wall flexibility on earth pressure, bending moments and failure modes is studied. Numerical models are compared to results from model tests carried out in a geotechnical centrifuge. The back-fill is dry sand and failure is introduced by allowing the wall to rotate around the anchor...... level. The Finite element program PLAXIS is used and two material models are evaluated, the Mohr-Coulomb model and the Hardening Soil model. The differences between the two concern the deformation properties. Generally good agreement was observed between physical and numerical models. The HS...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-09-30

    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.

  1. Satellite Earth observation data to identify anthropogenic pressures in selected protected areas

    Science.gov (United States)

    Nagendra, Harini; Mairota, Paola; Marangi, Carmela; Lucas, Richard; Dimopoulos, Panayotis; Honrado, João Pradinho; Niphadkar, Madhura; Mücher, Caspar A.; Tomaselli, Valeria; Panitsa, Maria; Tarantino, Cristina; Manakos, Ioannis; Blonda, Palma

    2015-05-01

    Protected areas are experiencing increased levels of human pressure. To enable appropriate conservation action, it is critical to map and monitor changes in the type and extent of land cover/use and habitat classes, which can be related to human pressures over time. Satellite Earth observation (EO) data and techniques offer the opportunity to detect such changes. Yet association with field information and expert interpretation by ecologists is required to interpret, qualify and link these changes to human pressure. There is thus an urgent need to harmonize the technical background of experts in the field of EO data analysis with the terminology of ecologists, protected area management authorities and policy makers in order to provide meaningful, context-specific value-added EO products. This paper builds on the DPSIR framework, providing a terminology to relate the concepts of state, pressures, and drivers with the application of EO analysis. The type of pressure can be inferred through the detection of changes in state (i.e. changes in land cover and/or habitat type and/or condition). Four broad categories of changes in state are identified, i.e. land cover/habitat conversion, land cover/habitat modification, habitat fragmentation and changes in landscape connectivity, and changes in plant community structure. These categories of change in state can be mapped through EO analyses, with the goal of using expert judgement to relate changes in state to causal direct anthropogenic pressures. Drawing on expert knowledge, a set of protected areas located in diverse socio-ecological contexts and subject to a variety of pressures are analysed to (a) link the four categories of changes in state of land cover/habitats to the drivers (anthropogenic pressure), as relevant to specific target land cover and habitat classes; (b) identify (for pressure mapping) the most appropriate spatial and temporal EO data sources as well as interpretations from ecologists and field data useful in connection with EO data analysis. We provide detailed examples for two protected areas, demonstrating the use of EO data for detection of land cover/habitat change, coupled with expert interpretation to relate such change to specific anthropogenic pressures. We conclude with a discussion of the limitations and feasibility of using EO data and techniques to identify anthropogenic pressures, suggesting additional research efforts required in this direction.

  2. Validating and calibrating the Nintendo Wii balance board to derive reliable center of pressure measures.

    Science.gov (United States)

    Leach, Julia M; Mancini, Martina; Peterka, Robert J; Hayes, Tamara L; Horak, Fay B

    2014-01-01

    The Nintendo Wii balance board (WBB) has generated significant interest in its application as a postural control measurement device in both the clinical and (basic, clinical, and rehabilitation) research domains. Although the WBB has been proposed as an alternative to the "gold standard" laboratory-grade force plate, additional research is necessary before the WBB can be considered a valid and reliable center of pressure (CoP) measurement device. In this study, we used the WBB and a laboratory-grade AMTI force plate (AFP) to simultaneously measure the CoP displacement of a controlled dynamic load, which has not been done before. A one-dimensional inverted pendulum was displaced at several different displacement angles and load heights to simulate a variety of postural sway amplitudes and frequencies (postural sway (which differs from our simulated postural sway in both amplitude and frequency content), it may be used to measure CoP displacement in situations where lower accuracy and precision is acceptable. PMID:25268919

  3. Magnetopause pressure balance in subsolar point during northward IMF orientation and high level of turbulence in magnetosheath in accordance with THEMIS data

    International Nuclear Information System (INIS)

    Complete text of publication follows. Plasma static and dynamic, magnetic pressure variations at the subsolar point of the magnetosphere of the Earth are studied using data of THEMIS satellites. The interval when interplanetary magnetic field (IMF) had the northward orientation and magnetopause crossings had features near to the tangentional discontinuity was selected. 18 magnetopause crossings were analyzed. Great variations of plasma flow parameters and magnetic field were simultaneously observed in the magnetosheath (turbulent magnetosheath). It is shown that in spite of such great magnetosheath variations and limited applicability of MHD approximation to the noncollisional plasma, the condition of stress balance is fulfilled in the limited regions near magnetopause just before the magnetopause and after it. The problem of magnetosheath plasma penetration inside the magnetosphere is discussed.

  4. Local structure around rare-earth ions in B2O3 glass at high pressure

    International Nuclear Information System (INIS)

    Melt quenching of B2O3 with less than 25 mol. % rare-earth oxide (RE2O3) at ambient pressure results in a milky white glass because of liquid-liquid phase separation into B2O3 and RE2O3·3B2O phases. In contrast, we have found that melt quenching under GPa-order pressure realizes a transparent RE-doped B2O3 glass. This study investigates the local structure around the RE ions in the B2O3 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.

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

    OpenAIRE

    Kosho Kasuga; Hiroki Sugiura; Shinichi Demura; Shigeki Matsuda

    2012-01-01

    This study aimed to examine the trial-to-trial reliability and sex differences in a foot pressure load balance test and its relationship to physical characteristics in 396 preschool children (201 boys and 195 girls). The subjects were asked to maintain an upright standing posture for 10 seconds three times on the Footview Clinic, an instrument designed to calculate the right-left and anterior-posterior ratios of foot pressure load. The ratios of the left and anterior foot pressure loads in ri...

  6. THE INFLUENCE OF PRESSURE-DEPENDENT VISCOSITY ON THE THERMAL EVOLUTION OF SUPER-EARTHS

    International Nuclear Information System (INIS)

    We study the thermal evolution of super-Earths with a one-dimensional (1D) parameterized convection model that has been adopted to account for a strong pressure dependence of the viscosity. A comparison with a 2D spherical convection model shows that the derived parameterization satisfactorily represents the main characteristics of the thermal evolution of massive rocky planets. We find that the pressure dependence of the viscosity strongly influences the thermal evolution of super-Earths—resulting in a highly sluggish convection regime in the lower mantles of those planets. Depending on the effective activation volume and for cooler initial conditions, we observe with growing planetary mass even the formation of a conductive lid above the core-mantle boundary (CMB), a so-called CMB-lid. For initially molten planets our results suggest no CMB-lids but instead a hot lower mantle and core as well as sluggish lower mantle convection. This implies that the initial interior temperatures, especially in the lower mantle, become crucial for the thermal evolution—the thermostat effect suggested to regulate the interior temperatures in terrestrial planets does not work for massive planets if the viscosity is strongly pressure dependent. The sluggish convection and the potential formation of the CMB-lid reduce the convective vigor throughout the mantle, thereby affecting convective stresses, lithospheric thicknesses, and heat fluxes. The pressure dependence of the viscosity may therefore also strongly affect the propensity of plate tectonics, volcanic activity, and the generation of a magnetic field of super-Earths.

  7. Crystal structure, equation of state, and elasticity of phase H (MgSiO4H2) at Earths lower mantle pressures

    Science.gov (United States)

    Tsuchiya, Jun; Mookherjee, Mainak

    2015-10-01

    Dense hydrous magnesium silicate (DHMS) phases play a crucial role in transporting water in to the Earths interior. A newly discovered DHMS, phase H (MgSiO4H2), is stable at Earths lower mantle, i.e., at pressures greater than 30?GPa. Here we report the crystal structure and elasticity of phase H and its evolution upon compression. Using first principles simulations, we have explored the relative energetics of the candidate crystal structures with ordered and disordered configurations of magnesium and silicon atoms in the octahedral sites. At conditions relevant to Earths lower mantle, it is likely that phase H is able to incorporate a significant amount of aluminum, which may enhance the thermodynamic stability of phase H. The sound wave velocities of phase H are ~24% smaller than those of isostructural ?-AlOOH. The shear wave impedance contrast due to the transformation of phase D to a mixture of phase H and stishovite at pressures relevant to the upper part of the lower mantle could partly explain the geophysical observations. The calculated elastic wave velocities and anisotropies indicate that phase H can be a source of significant seismic anisotropy in the lower mantle.

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

    Science.gov (United States)

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

    2006-12-01

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

  9. Electron spin transition causing structure transformations of earth's interiors under high pressure

    Science.gov (United States)

    Yamanaka, T.; Kyono, A.; Kharlamova, S.; Alp, E.; Bi, W.; Mao, H.

    2012-12-01

    To elucidate the correlation between structure transitions and spin state is one of the crucial problems for understanding the geophysical properties of earth interiors under high pressure. High-pressure studies of iron bearing spinels attract extensive attention in order to understand strong electronic correlation such as the charge transfer, electron hopping, electron high-low spin transition, Jahn-Teller distortion and charge disproponation in the lower mantle or subduction zone [1]. Experiment Structure transitions of Fe3-xSixO4, Fe3-xTixO4 Fe3-xCrxO4 spinel solid solution have been investigated at high pressure up to 60 GPa by single crystal and powder diffraction studies using synchrotron radiation with diamond anvil cell. X-ray emission experiment (XES) at high pressure proved the spin transition of Fe-Kβ from high spin (HS) to intermediate spin state (IS) or low spin state (LS). Mössbauer experiment and Raman spectra study have been also conducted for deformation analysis of Fe site and confirmation of the configuration change of Fe atoms. Jahn-Teller effect A cubic-to-tetragonal transition under pressure was induced by Jahn-Teller effect of IVFe2+ (3d6) in the tetrahedral site of Fe2TiO4 and FeCr2O4, providing the transformation from 43m (Td) to 42m (D2d). Tetragonal phase is formed by the degeneracy of e orbital of Fe2+ ion. Their c/a ratios are c/aMine, S. Asogawa and Y. Nakamoto Physical Review B 80, 134120 (2009)

  10. X-ray absorption experiments on rare earth and uranium compounds under high pressure

    International Nuclear Information System (INIS)

    After an introduction into the phenomenon of the mixed valency and the method of measuring the microstructures by X-ray absorption spectroscopy in the area of the L edges under pressure, the results of investigations at selected substitutes of the chalcogenides and puictides of the rare earths and the uranium were given. Thus, pressure-induced valency transitions in YbS and YbTe, instabilities in valency and structural phase transitions in EUS and SmTe as well as the change in the electron structure in USb under pressure were investigated in order to answer questions of solid state physics (e.g. semiconductor-metal transitions, correlation between valency and structural phase transitions). Hybridization effects in LIII spectra of formally tetravalent Ca are analyzed at CeF4 and CeO2 (insulators) and the role of final state effects in the LIII spectra are analyzed at EuP2P2 and TmSe-TmTe (semiconductor systems). (RB)

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

    International Nuclear Information System (INIS)

    Emission related to rare earth ions in solids takes place usually due to 4fn → 4fn and 4fn−15d1 → 4fn 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 Eu2+ the impurity trapped exciton states become stable and contribute to the radiative processes though anomalous luminescence that appears apart of the 4f7 → 4f7 and 4f75d1 → 5f7 emission. In this contribution pressure effect on energies of the 4fn−15d1→5fn 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 Pr3+, and Eu2+ in different lattices are reviewed.

  12. Present-day and future Antarctic ice sheet climate and surface mass balance in the Community Earth System Model

    Science.gov (United States)

    Lenaerts, Jan T. M.; Vizcaino, Miren; Fyke, Jeremy; van Kampenhout, Leo; van den Broeke, Michiel R.

    2016-02-01

    We present climate and surface mass balance (SMB) of the Antarctic ice sheet (AIS) as simulated by the global, coupled ocean-atmosphere-land Community Earth System Model (CESM) with a horizontal resolution of ˜1° in the past, present and future (1850-2100). CESM correctly simulates present-day Antarctic sea ice extent, large-scale atmospheric circulation and near-surface climate, but fails to simulate the recent expansion of Antarctic sea ice. The present-day Antarctic ice sheet SMB equals 2280 ± 131 {Gt year^{-1}} , which concurs with existing independent estimates of AIS SMB. When forced by two CMIP5 climate change scenarios (high mitigation scenario RCP2.6 and high-emission scenario RCP8.5), CESM projects an increase of Antarctic ice sheet SMB of about 70 {Gt year^{-1}} per degree warming. This increase is driven by enhanced snowfall, which is partially counteracted by more surface melt and runoff along the ice sheet's edges. This intensifying hydrological cycle is predominantly driven by atmospheric warming, which increases (1) the moisture-carrying capacity of the atmosphere, (2) oceanic source region evaporation, and (3) summer AIS cloud liquid water content.

  13. Global mechanisms in atmosphere models and a balance of the Earth angle moment. Atmosphere radio-waveguides and teleconnection

    International Nuclear Information System (INIS)

    Complete text of publication follows. The satellite data and data of observing the radio-waveguide parameters (especially in the low troposphere layers) by means of radio-technical devices (in the ultra short-wave diapason) is the informative basis of the modern atmosphere long-termed forecasts. As any water quantities in atmosphere are formed on the basis of the cycle- and front-genesis (or in the convective non-stability lines) one can introduce the corresponding model on the basis of thermodynamics and hydro-mechanics of the corresponding processes [1,2]. For example, physics of these processes can coincide with the soliton mechanics, which has the long-periodical basis of the energy support. The action mechanics of such a soliton defines the key thermo-hydro-dynamical parameters of the atmosphere ultra-short-wave radio-waveguide. We present new approach to modeling a role of the atmosphere circulations forms in definition of the long-periodical processes in atmosphere, parameters of the troposphere ultra-short-wave radio-waveguides and the Earth angle momentum balance. We carried out a series of the computer experiments to provide new predictors for the long-termed and super long-termed forecasts of the low frequency atmospheric processes. Besides, we have adapted the modified theory of the macro-turbulence for possible using the atmosphere radio-waveguides as a special effective predictors in the long-termed plan.

  14. Carbon content in the Earth's inner core from the elasticity of iron carbide at high pressure

    Science.gov (United States)

    Steinle-Neumann, G.; Mookherjee, M.

    2009-12-01

    Discrepancy between sound wave velocity of Fe-Ni alloys and seismological models indicate that Earths core is likely to contain lighter elements such as H, C, O, Si and S. Carbon is a plausible candidate because of its cosmic abundance and chemical affinity to iron at low pressures. Earlier it was thought that carbon, being volatile might have been lost during the accretionary stages of the planet. However, it is now known, that core formation likely took place from the deep magma ocean surrounded by solar-nebula type proto-atmosphere enriched in volatiles thus enabling incorporation of volatiles in to the molten core. Experimental studies conducted to study the phase diagram of Fe-C system revealed that volatility of carbon is only significant at pressures lower than 10-5 GPa. (Wood, 1993, EPSL, 117, 593) suggested that solid inner core might be composed of Fe3C. Recent experimental studies have extended the Fe-C phase diagram to considerably higher pressures (~70 GPa) and have found that Fe7C3 is the likely phase at the inner core conditions (Lord et al., 2009, EPSL, 284, 157). In this study we determine the elasticity of Fe7C3 using first principle methods. Results of compression for the ferromagnetic Fe7C3 is well represented by a third order Birch Murnaghan finite strain expression with K0~ 275 GPa, K?~2.5 and V0~ 182 3. Under compression magnetic moment gradually decreases and at ~69 GPa magnetic moment is instantaneously lost. Similar behavior has been reported for Fe3C at 60 GPa (Vocadlo et al., 2002, EPSL, 203, 567). The high-pressure non-magnetic phase has distinct elastic parameters with K0~ 228 GPa, K?~4.9 and V0~ 181 3. Calculated elastic constants also exhibit softening associated with the loss of magnetization. Similar anomalous behavior in thermoelastic parameter owing to loss of magnetization has been observed for Fe3C (Fiquet et al. 2009, PEPI, 172, 125) at 68 GPa. We will present full elastic tensor and sound wave velocity results for ferromagnetic and non-magnetic phase and infer about the carbon content of the inner core.

  15. Three-Month Test-Retest Reliability of Center of Pressure Motion During Standing Balance in Individuals with Multiple Sclerosis

    Science.gov (United States)

    Wajda, Douglas A.; Motl, Robert W.

    2016-01-01

    Background: Balance impairment and an increased rate of falls are commonly reported in individuals with multiple sclerosis (MS). Force platform–generated center of pressure (COP) metrics have previously been recommended as an outcome measure to quantify balance deficits and distinguish between fallers and nonfallers in MS. Information is limited regarding the preservation of postural control in individuals with MS over extended time frames in the absence of an intervention. This report examines the test-retest reliability and magnitude of change of COP motion during standing balance over 3 months. Methods: Twenty individuals with MS and a history of falling underwent testing on two occasions 3 months apart in the absence of an intervention. On both occasions, participants completed two 30-second trials of three conditions: eyes open, eyes closed, and eyes open with concurrent cognitive challenge (dual task). Measures of COP area, velocity, and temporal structure were calculated and included in the reliability analysis. Results: The COP metrics displayed fair-to-excellent reliability over 3 months without an intervention. Reliability was maintained across the three commonly used balance conditions. Conclusions: These results offer insight into the reliability of COP measures over a 3-month period in MS and can inform the use of COP metrics for future study design (eg, sample size estimates) and balance outcome assessment during randomized controlled trials and fall-prevention studies in individuals with MS.

  16. Total energy calculations using DFT+DMFT: computing the pressure phase diagram of the rare earth nickelates

    OpenAIRE

    Park, Hyowon; Millis, Andrew J.; Marianetti, Chris A.

    2013-01-01

    A full implementation of the $ab$ $initio$ density functional plus dynamical mean field theory (DFT+DMFT) formalism to perform total energy calculations and structural relaxations is proposed and implemented. The method is applied to the structural and metal-insulator transitions of the rare earth nickelate perovskites as a function of rare earth ion, pressure, and temperature. In contrast to previous DFT and DFT+$U$ theories, the present method accounts for the experimentally observed struct...

  17. 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)

    V.S. Korovkin

    2013-10-01

    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.

  18. Towards the bulk carbon content of Earth; new metal carbide geobarometer in high pressure diamond.

    Science.gov (United States)

    Jones, A. P.; Dobson, D.; Milledge, H. J.

    2009-04-01

    Formation of the metallic core in Earth (and other terrestrial planets) is not thought to have completely removed metallic iron from the lower mantle, where metallic iron might therefore be expected to occur as a widespread minor component [1]. We provide a new interpretation of metallic carbide inclusions in some diamond, which support a very high pressure origin from the lower mantle. Unlike rare carbides reported from diamonds previously without silicon [2], some diamonds from Jagersfontein coexist with iron-rich carbides which do contain significant silicon and oxygen, including in some cases their partial exsolution products. Based on an experimental calibration for liquid iron coexisting with lower mantle perovskite [3], we are able to show that some carbides were likely derived from pressures of approximately 45 GPa, or depths of >1100 km. This potential geobarometer has not been corrected for the behaviour of carbon in the liquid iron system, which might be an important experimental goal. The recognition of this independent carbide geobarometer offers an important new tool to confirm the superdeep origin of some diamond. The carbide-bearing diamonds are from a group whose charcteristics have recently been described [5]. Their distinctive light carbon isotopic signature (13^C ~ 17 ) coupled with evidence for very low contents nitrogen which is nonetheless highly aggregated, might be interpreted as indicative of subducted carbon. However, we are also open to the possibility that the bulk carbon isotopic composition of the Earth might also be different from the normal mantle value (13^C ~ 6 ), in which case the potential 0.4 wt% C in the Earth's core could also be isotopically very light, as suggested by Grady et al [6]. References [1] Frost D et al, Nature 428, 409-412 (2004) [2] Jacob D E et al, Contrib. Mineral. Petrol., 146, 566-576 (2004) [3] Lin et al, Science, 295, 313-315 (2002) [4] Dubrovinsky L. et al, Nature 422, 58-61 (2003) [5] Jones A P et al, 9th Int Kimb Conf 9IKC-A-00360 (2008) [6] Grady et al, Int. J. Astrobiol. 3, 117-124 (2004)

  19. High Pressure Effects on the Superconductivity in Rare-Earth Doped CaFe2As2

    OpenAIRE

    Cargill, Dan; Uhoya, Walter; Krzysztof, Gofryk; Tsoi, Georgiy M.; Vohra, Yogesh K.; Sefat, Athena S; Weir, S. T .

    2013-01-01

    High-pressure superconductivity in a rare-earth doped Ca0.86Pr0.14Fe2As2 single crystalline sample has been studied up to 12 GPa and temperatures down to 11 K using designer diamond anvil cell under a quasi-hydrostatic pressure medium. The electrical resistance measurements were complemented by high pressure and low temperature x-ray diffraction studies at a synchrotron source. The electrical resistance measurements show an intriguing observation of superconductivity under pressure, with Tc a...

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

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.

  1. Influence of atmospheric pressure on the Free Core Nutation, precession and some forced nutational motions of the Earth

    Science.gov (United States)

    Gegout, P.; Hinderer, J.; Legros, H.; Greff, M.; Dehant, V.

    1998-04-01

    The atmospheric pressure effects on the Earth's Free Core Nutation (FCN) and some forced nutations are evaluated numerically from the global pressure field provided by the European Center for Medium Range Weather Forecast (ECMWF) on the Earth's solid surface using a 12-year long pressure data set sampled every 6 h on a (1.125°×1.125°) grid. Our model incorporates both the pressure and gravitational torques from the atmosphere as well as the elastic deformational effects induced by atmospheric loading. The pressure torque is computed from the surface pressure field acting on the Earth's topography and the antagonist gravitational torque is also dependent on this pressure field but acting on the gravitational equipotential surface (assuming vertical hydrostatic equilibrium between density and pressure). The response of the oceans to pressure excitation is approximated by the static ocean model which is different from the classical non-inverted barometer (NIBO) and the inverted barometer (IBO) hypotheses and depends on the degree of the spherical harmonic decomposition of the pressure field. The most efficient term in perturbing the nutations is the S 1 solar barometric tide of thermal origin which induces a contribution to the prograde annual nutation of gravitational origin. Seasonal modulations of S 1 also appear clearly which cause perturbations to other nutations. We show that the contributions to the nutation values are ranging from a few tenths of a milliarcsecond up to the milliarcsecond for the annual prograde term and therefore are close to the lower bounds of the values from a previous calculation by Dehant et al. [Dehant, V., Bizouard, Ch., Hinderer, J., Legros, H., Lefftz, M., 1996. On atmospheric pressure perturbation on precession and nutations. Phys. Earth Planet. Interiors 96, 25-39.] based on the 20-yr-old S 1 pressure field from Haurwitz and Cowley [Haurwitz, B., Cowley, A.D., 1973. The diurnal and semidiurnal barometric oscillations, global distribution and annual variation. Pageoph. 102, 193-222.] and speculations on its amplitude modulation. These effects are therefore not negligible and this study points out the importance of atmospheric pressure corrections on the gravitational nutations of lunisolar origin. We also estimate the excitation power available from the atmospheric pressure, gravitational torques and elastic surface loading to explain the mean observed FCN amplitude as derived from VLBI (Very Long Baseline Interferometry) observations. It is suggested that the atmosphere is a good candidate for randomly exciting this free rotational mode.

  2. 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)

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

    1995-12-15

    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.

  3. Validating and Calibrating the Nintendo Wii Balance Board to Derive Reliable Center of Pressure Measures

    Directory of Open Access Journals (Sweden)

    Julia M. Leach

    2014-09-01

    Full Text Available The Nintendo Wii balance board (WBB has generated significant interest in its application as a postural control measurement device in both the clinical and (basic, clinical, and rehabilitation research domains. Although the WBB has been proposed as an alternative to the “gold standard” laboratory-grade force plate, additional research is necessary before the WBB can be considered a valid and reliable center of pressure (CoP measurement device. In this study, we used the WBB and a laboratory-grade AMTI force plate (AFP to simultaneously measure the CoP displacement of a controlled dynamic load, which has not been done before. A one-dimensional inverted pendulum was displaced at several different displacement angles and load heights to simulate a variety of postural sway amplitudes and frequencies (<1 Hz. Twelve WBBs were tested to address the issue of inter-device variability. There was a significant effect of sway amplitude, frequency, and direction on the WBB’s CoP measurement error, with an increase in error as both sway amplitude and frequency increased and a significantly greater error in the mediolateral (ML (compared to the anteroposterior (AP sway direction. There was no difference in error across the 12 WBB’s, supporting low inter-device variability. A linear calibration procedure was then implemented to correct the WBB’s CoP signals and reduce measurement error. There was a significant effect of calibration on the WBB’s CoP signal accuracy, with a significant reduction in CoP measurement error (quantified by root-mean-squared error from 2–6 mm (before calibration to 0.5–2 mm (after calibration. WBB-based CoP signal calibration also significantly reduced the percent error in derived (time-domain CoP sway measures, from −10.5% (before calibration to −0.05% (after calibration (percent errors averaged across all sway measures and in both sway directions. In this study, we characterized the WBB’s CoP measurement error under controlled, dynamic conditions and implemented a linear calibration procedure for WBB CoP signals that is recommended to reduce CoP measurement error and provide more reliable estimates of time-domain CoP measures. Despite our promising results, additional work is necessary to understand how our findings translate to the clinical and rehabilitation research domains. Once the WBB’s CoP measurement error is fully characterized in human postural sway (which differs from our simulated postural sway in both amplitude and frequency content, it may be used to measure CoP displacement in situations where lower accuracy and precision is acceptable.

  4. 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.

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

    Science.gov (United States)

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

    2012-11-01

    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.

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

    Science.gov (United States)

    Syrek, Christine J; Apostel, Ella; Antoni, Conny H

    2013-07-01

    The objective of this article is to investigate transformational leadership as a potential moderator of the negative relationship of time pressure to work-life balance and of the positive relationship between time pressure and exhaustion. Recent research regards time pressure as a challenge stressor; while being positively related to motivation and performance, time pressure also increases employee strain and decreases well-being. Building on the Job Demand-Resources model, we hypothesize that transformational leadership moderates the relationships between time pressure and both employees' exhaustion and work-life balance such that both relationships will be weaker when transformational leadership is higher. Of seven information technology organizations in Germany, 262 employees participated in the study. Established scales for time pressure, transformational leadership, work-life balance, and exhaustion were used, all showing good internal consistencies. The results support our assumptions. Specifically, we find that under high transformational leadership the impact of time pressure on exhaustion and work-life balance was less strong. The results of this study suggest that, particularly under high time pressure, transformational leadership is an important factor for both employees' work-life balance and exhaustion. PMID:23834443

  7. Universal viscosity growth in metallic melts at megabar pressures: the vitreous state of the Earth's inner core

    International Nuclear Information System (INIS)

    Experimental data on and theoretical models for the viscosity of various types of liquids and melts under pressure are reviewed. Experimentally, the least studied melts are those of metals, whose viscosity is considered to be virtually constant along the melting curve. The authors' new approach to the viscosity of melts involves the measurement of the grain size in solidified samples. Measurements on liquid metals at pressures up to 10 GPa using this method show, contrary to the empirical approach, that the melt viscosity grows considerably along the melting curves. Based on the experimental data and on the critical analysis of current theories, a hypothesis of a universal viscosity behavior is introduced for liquids under pressure. Extrapolating the liquid iron results to the pressures and temperatures at the Earth's core reveals that the Earth's outer core is a very viscous melt with viscosity values ranging from 102 Pa s to 1011 Pa s depending on the depth. The Earth's inner core is presumably an ultraviscous (>1011 Pa s) glass-like liquid - in disagreement with the current idea of a crystalline inner core. The notion of the highly viscous interior of celestial bodies sheds light on many mysteries of planetary geophysics and astronomy. From the analysis of the pressure variation of the melting and glass-transition temperatures, an entirely new concept of a stable metallic vitreous state arises, calling for further experimental and theoretical study. (reviews of topical problems)

  8. A well-balanced scheme for a one-pressure model of two-phase flows

    Energy Technology Data Exchange (ETDEWEB)

    Mai Duc Thanh [Department of Mathematics, International University, Quarter 6, Linh Trung Ward, Thu Duc District, Ho Chi Minh City (Viet Nam); Ismail, Ahmad Izani Md [School of Mathematical Sciences, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia)], E-mail: mdthanh@hcmiu.edu.vn, E-mail: izani@cs.usm.my

    2009-06-15

    We consider a model of two-phase flows in which one phase is compressible and the other is incompressible. The system is a closed system with four governing equations for four unknowns. We construct a well-balanced scheme for this system. We then supplement the scheme with a practical modification so that it is always well defined. Our scheme is shown to be capable of maintaining equilibrium states.

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

    Directory of Open Access Journals (Sweden)

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

    2011-06-01

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

  10. Accuracy of force and center of pressure measures of the Wii Balance Board.

    Science.gov (United States)

    Bartlett, Harrison L; Ting, Lena H; Bingham, Jeffrey T

    2014-01-01

    The Nintendo Wii Balance Board (WBB) is increasingly used as an inexpensive force plate for assessment of postural control; however, no documentation of force and COP accuracy and reliability is publicly available. Therefore, we performed a standard measurement uncertainty analysis on 3 lightly and 6 heavily used WBBs to provide future users with information about the repeatability and accuracy of the WBB force and COP measurements. Across WBBs, we found the total uncertainty of force measurements to be within ± 9.1N, and of COP location within ± 4.1mm. However, repeatability of a single measurement within a board was better (4.5 N, 1.5mm), suggesting that the WBB is best used for relative measures using the same device, rather than absolute measurement across devices. Internally stored calibration values were comparable to those determined experimentally. Further, heavy wear did not significantly degrade performance. In combination with prior evaluation of WBB performance and published standards for measuring human balance, our study provides necessary information to evaluate the use of the WBB for analysis of human balance control. We suggest the WBB may be useful for low-resolution measurements, but should not be considered as a replacement for laboratory-grade force plates. PMID:23910725

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

    Science.gov (United States)

    Bolman, J.; Nall, J.

    2005-05-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Cheng-Wei Huang

    2013-08-01

    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.

  13. Effects on the location of the centre of gravity and the foot pressure contribution to standing balance associated with ageing.

    Science.gov (United States)

    Tanaka, T; Takeda, H; Izumi, T; Ino, S; Ifukube, T

    1999-07-01

    The aim was to analyse the limitation of the head and lumbar movements in relation to the centre of gravity which is needed to maintain standing balance with ageing. The participants of the study were 25 healthy volunteers divided into two age categories, the young group (mean 22.4 +/- 2.7 years) and the elderly group (mean 71.2 +/- 3.6 years). The instruments for measuring the movements of the lumbar region and head and the centre of pressure (COP) were a 3-D motion analysis system and a force plate. In addition, the peak foot pressure was measured during standing using the F-Scan system. The participants were first asked to stand relaxed for 10 s. They then shifted from the starting position to the four directions of sway: anterior, posterior, right and left. They were asked to maintain standing balance at the maximal distance position for each sway as much as possible for 10 s. Analysis of parameters was performed by measuring the average maximal linear displacement (cm) of the head and lumbar markers, the COP (cm), and the peak foot pressure (% of body weight per cm2) in each participant. The data of the young group for lumbar maximal displacement were greater than those of the elderly group in the anterior, posterior and lateral sways. A significant difference between the young and elderly data was found in the posterior sway. According to the data of the head's maximal displacement, the elderly group's data were greater than the young group's data in all sways, except for the anterior side. For the data of peak foot pressure in the posterior sway, the elderly group's data was greater than the young group's data. The forefoot area data of the young group was significantly greater than that of the elderly group, and the heel area data of the elderly was significantly greater than that of the young group in the right sway. The results suggest that the maximal displacement of head and lumbar positions and the toe's muscle activity in the forefoot are important factors associated with the centre of gravity in elderly adults. It is postulated that each base of support area of the older adults in smaller than that of younger adults. These variables could be made available as a clinical test for the degree of poor balance. PMID:10424187

  14. Sodium-potassium balance in the regulation of high blood pressure

    Directory of Open Access Journals (Sweden)

    Luis Hernán Zárate Méndez

    2012-02-01

    Full Text Available The World Health Organization considers essential hypertension as a primary cause of death. Twenty-five percent of the population over 15 has high blood pressure (HBP, equivalent to a billion people. It has been predicted that this group will increase by 60%, lineal with age increase in the overall population. Unfortunately, detection, treatment and effective control of HBP, are deficient both in Chile and in the rest of the world, making it an unresolved health problem demanding urgent attention. The recently conducted Chilean National Health Survey (2009-2010 revealed a 26.9% prevalence of this condition in the population, sixty-five percent of individuals are aware of their condition, 37.6% are in treatment and only 16,49% are effectively controlled. Furthermore, the survey reveals unhealthy life-style markers, which explains the epidemic that besets the country as there are multiple risk factors at stake. This review focuses mainly on the importance of the sodium-potassium relationship in the regulation of high blood pressure. It must be pointed out that all of the studies underscore the importance of sodium in the genesis of hypertension because of its effects of blood pressure, especially in sensitive individuals, while little attention has been given to the manifold beneficial actions of potassium in the regulation of blood pressure.

  15. Super earth interiors and validity of Birch's Law for ultra-high pressure metals and ionic solids

    Science.gov (United States)

    Ware, Lucas Andrew

    2015-01-01

    Super Earths, recently detected by the Kepler Mission, expand the ensemble of known terrestrial planets beyond our Solar System's limited group. Birch's Law and velocity-density systematics have been crucial in constraining our knowledge of the composition of Earth's mantle and core. Recently published static diamond anvil cell experimental measurements of sound velocities in iron, a key deep element in most super Earth models, are inconsistent with each other with regard to the validity of Birch's Law. We examine the range of validity of Birch's Law for several metallic elements, including iron, and ionic solids shocked with a two-stage light gas gun into the ultra-high pressure, temperature fluid state and make comparisons to the recent static data.

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

    Directory of Open Access Journals (Sweden)

    S. M. Daoud

    2014-02-01

    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

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

    CERN Document Server

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

    2007-01-01

    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.

  18. Origin of “memory glass” effect in pressure-amorphized rare-earth molybdate single crystals

    International Nuclear Information System (INIS)

    The memory glass effect (MGE) describes the ability of some materials to recover the initial structure and crystallographic orientation after pressure-induced amorphization (PIA). In spite of numerous studies the nature and underlying mechanisms of this phenomenon are still not clear. Here we report investigations of MGE in β′-Eu2(MoO4)3 single crystal samples subjected to high pressure amorphization. Using the XRD and TEM techniques we carried out detailed analysis of the structural state of high pressure treated single crystal samples as well as structural transformations due to subsequent annealing at atmospheric pressure. The structure of the sample has been found to be complex, mainly amorphous, however, the amorphous medium contains evenly distributed nanosize inclusions of a paracrystalline phase. The inclusions are highly correlated in orientation and act as “memory units” in the MGE. - Graphical abstract: Schematic representation of pressure-induced amorphization and “memory glass” effect in rare-earth molybdate single crystals. The XRD and TEM measurements have revealed the presence of the residual identically oriented paracrystalline nanodomains in the pressure-amorphized state. These domains preserve the information about initial structure and orientation of the sample. They act as memory units and crystalline seeds during transformation of the amorphous phase back to the starting single crystalline one. - Highlights: • Pressure-amorphized Eu2(MoO4)3 single crystals were studied ex-situ by XRD and TEM. • Tiny residual crystalline inclusions were found in amorphous matrix of sample. • The inclusions keep in memory the parent crystal structure and orientation. • The inclusions account for “memory glass” effect in rare-earth molibdates

  19. Origin of “memory glass” effect in pressure-amorphized rare-earth molybdate single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Willinger, Elena, E-mail: kudrenko@fhi-berlin.mpg.de [Institute of Solid State Physics, Russian Academy of Sciences, 142432 Chernogolovka (Russian Federation); Fritz-Haber Institute of the Max Planck Society, 14195 Berlin (Germany); Sinitsyn, Vitaly; Khasanov, Salavat; Redkin, Boris; Shmurak, Semeon; Ponyatovsky, Eugeny [Institute of Solid State Physics, Russian Academy of Sciences, 142432 Chernogolovka (Russian Federation)

    2015-02-15

    The memory glass effect (MGE) describes the ability of some materials to recover the initial structure and crystallographic orientation after pressure-induced amorphization (PIA). In spite of numerous studies the nature and underlying mechanisms of this phenomenon are still not clear. Here we report investigations of MGE in β′-Eu{sub 2}(MoO{sub 4}){sub 3} single crystal samples subjected to high pressure amorphization. Using the XRD and TEM techniques we carried out detailed analysis of the structural state of high pressure treated single crystal samples as well as structural transformations due to subsequent annealing at atmospheric pressure. The structure of the sample has been found to be complex, mainly amorphous, however, the amorphous medium contains evenly distributed nanosize inclusions of a paracrystalline phase. The inclusions are highly correlated in orientation and act as “memory units” in the MGE. - Graphical abstract: Schematic representation of pressure-induced amorphization and “memory glass” effect in rare-earth molybdate single crystals. The XRD and TEM measurements have revealed the presence of the residual identically oriented paracrystalline nanodomains in the pressure-amorphized state. These domains preserve the information about initial structure and orientation of the sample. They act as memory units and crystalline seeds during transformation of the amorphous phase back to the starting single crystalline one. - Highlights: • Pressure-amorphized Eu{sub 2}(MoO4){sub 3} single crystals were studied ex-situ by XRD and TEM. • Tiny residual crystalline inclusions were found in amorphous matrix of sample. • The inclusions keep in memory the parent crystal structure and orientation. • The inclusions account for “memory glass” effect in rare-earth molibdates.

  20. Chaotic behavior of water column oscillator simulating pressure balanced injection system in passive safety reactor

    International Nuclear Information System (INIS)

    Japan Atomic Energy Research Institute (JAERI) proposed a passive safety reactor called the System-integrated Pressurized Water Reactor (SPWR). In a loss of coolant accident, the Pressurizing Line (PL) and the Injection Line (IL) are passively opened. Vapor generated by residual heat pushes down the water level in the Reactor Vessel (RV). When the level is lower than the inlet of the PL, the vapor is ejected into the Containment Vessel (CV) through the PL. Then boronized water in the CV is injected into the RV through the IL by the static head. In an experiment using a simple apparatus, gas ejection and water injection were found to occur alternately under certain conditions. The gas ejection interval was observed to fluctuate considerably. Though stochastic noise affected the interval, the experimental results suggested that the large fluctuation was produced by an inherent character in the system. A set of piecewise linear differential equations was derived to describe the experimental result. The large fluctuation was reproduced in the analytical solution. Thus it was shown to occur even in a deterministic system without any source of stochastic noise. Though the derived equations simulated the experiment well, they had ten independent parameters governing the behavior of the solution. There appeared chaotic features and bifurcation, but the analytical model was too complicated to examine the features and mechanism of bifurcation. In this study, a new simple model is proposed which consists of a set of piecewise linear ordinary differential equations with only four independent parameters. (authors)

  1. Pressure and current balance conditions during electron beam injections from spacecraft

    Science.gov (United States)

    Hwang, K. S.; Singh, Nagendra

    1990-01-01

    Electrostatic charging level of a conducting surface in response to injections of electron beams into space plasma is investigated by means of one-dimensional Vlasov code. Injections of Maxwellian beams into a vacuum shows that the surface can charge up to an electric potential phi sub s greater than W sub b, where W sub b is the average electron beam energy. Since Maxwellian beams have extended trails with electrons having energies greater than W sub b, it is difficult to quantify the charging level in terms of the energies of the injected electrons. In order to quantitatively understand the charging in excess of W sub b, simulations were carried out for water-bag types of beam with velocity distribution functions described by f(V) = A for V sub min approx. less than V approx. less than V sub max and f(V) = O otherwise, where A is a constant making the normalized beam density unity. It is found that V sub max does not directly determine the charging level. The pressure distribution in the electron sheath determines the electric field distribution near the surface. The electric field in turn determines the electrostatic potential of the vehicle. The pressure distribution is determined by the beam parameters such as the average beam velocity and the velocity spread of the beam.

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

    CERN Document Server

    Wolf, M

    2013-01-01

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

  3. Seasonal Variations of the Earth's Gravitational Field: An Analysis of Atmospheric Pressure, Ocean Tidal, and Surface Water Excitation

    Science.gov (United States)

    Dong, D,; Gross, R.S.; Dickey, J.

    1996-01-01

    Monthly mean gravitational field parameters (denoted here as C(sub even)) that represent linear combinations of the primarily even degree zonal spherical harmonic coefficients of the Earth's gravitational field have been recovered using LAGEOS I data and are compared with those derived from gridded global surface pressure data of the National meteorological center (NMC) spanning 1983-1992. The effect of equilibrium ocean tides and surface water variations are also considered. Atmospheric pressure and surface water fluctuations are shown to be the dominant cause of observed annual C(sub even) variations. Closure with observations is seen at the 1sigma level when atmospheric pressure, ocean tide and surface water effects are include. Equilibrium ocean tides are shown to be the main source of excitation at the semiannual period with closure at the 1sigma level seen when both atmospheric pressure and ocean tide effects are included. The inverted barometer (IB) case is shown to give the best agreement with the observation series. The potential of the observed C(sub even) variations for monitoring mass variations in the polar regions of the Earth and the effect of the land-ocean mask in the IB calculation are discussed.

  4. Inclusion of electronic polarizability effect in high pressure structural properties of alloy of rare-earth antimonides

    Energy Technology Data Exchange (ETDEWEB)

    Yaduvanshi, Namrata, E-mail: namrata-yaduvanshi@yahoo.com; Kapoor, Shilpa; Singh, Sadhna [High Pressure Research Lab. Department of Physics, Barkatullah University, Bhopal (M.P.) India-462026 (India)

    2015-05-15

    In the present paper, we have investigated the high-pressure structural phase transition of rare-earth antimonides (NdSb and DySb). We studied theoretically the structural properties of alloy of these compounds (NdSb and DySb) by using the three-body potential model with the effect of electronic polarizability (TBIPE{sub P}). These compounds exhibit first order crystallographic phase transition from NaCl (B{sub 1}) to CsCl (B{sub 2}) phase at 17.8 GPa and 22.6 GPa respectively. The study has been extended to mixed crystals and the effect of composition on transition pressure and volume change is investigated. The phase transition pressures and associated volume collapse obtained from present potential model (TBIPE{sub P}) show a good agreement with available experimental data.

  5. Inclusion of electronic polarizability effect in high pressure structural properties of alloy of rare-earth antimonides

    International Nuclear Information System (INIS)

    In the present paper, we have investigated the high-pressure structural phase transition of rare-earth antimonides (NdSb and DySb). We studied theoretically the structural properties of alloy of these compounds (NdSb and DySb) by using the three-body potential model with the effect of electronic polarizability (TBIPEP). These compounds exhibit first order crystallographic phase transition from NaCl (B1) to CsCl (B2) phase at 17.8 GPa and 22.6 GPa respectively. The study has been extended to mixed crystals and the effect of composition on transition pressure and volume change is investigated. The phase transition pressures and associated volume collapse obtained from present potential model (TBIPEP) show a good agreement with available experimental data

  6. Jump conditions for pressure anisotropy and comparison with the Earth's bow shock

    Directory of Open Access Journals (Sweden)

    D. F. Vogl

    2001-01-01

    Full Text Available Taking into account the pressure anisotropy in the solar wind, we study the magnetic field and plasma parameters downstream of a fast shock, as functions of upstream parameters and downstream pressure anisotropy. In our theoretical approach, we model two cases: a the perpendicular shock and b the oblique shock. We use two threshold conditions of plasma instabilities as additional equations to bound the range of pressure anisotropy. The criterion of the mirror instability is used for pressure anisotropy p perp /pparrallel > 1. Analogously, the criterion of the fire-hose instability is taken into account for pressure anisotropy p perp /pparrallel < 1. We found that the variations of the parallel pressure, the parallel temperature, and the tangential component of the velocity are most sensitive to the pressure anisotropy downstream of the shock. Finally, we compare our theory with plasma and magnetic field parameters measured by the WIND spacecraft.

  7. Strength and Balance Exercises

    Science.gov (United States)

    ... Pressure High Blood Pressure Tools & Resources Stroke More Strength and Balance Exercises Updated:Jun 23,2015 If ... Be Safe While Being Active - Stretching & Flexibility Exercises - Strength & Balance Exercises - Problems & Solutions for Being Active - FAQs ...

  8. Electron pressure balance in the SOL through the transition to detachment

    International Nuclear Information System (INIS)

    Upgrades to core and divertor Thomson scattering (DTS) diagnostics at DIII-D have provided measurements of electron pressure profiles in the lower divertor from attached- to fully-detached divertor plasma conditions. Detailed, multistep sequences of discharges with increasing line-averaged density were run at several levels of Pinj. Strike point sweeping allowed 2D divertor characterization using DTS optimized to measure Te down to 0.5 eV. The ionization front at the onset of detachment is found to move upwards in a controlled manner consistent with the indication that scrape-off layer parallel power flux is converted from conducted to convective heat transport. Measurements of ne, Te and pe in the divertor versus Lparallel demonstrate a rapid transition from Te ⩾ 15 eV to ⩽3 eV occurring both at the outer strike point and upstream of the X-point. These observations provide a strong benchmark for ongoing modeling of divertor detachment for existing and future tokamak devices

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

    CERN Document Server

    Jenkins, Edward B

    2008-01-01

    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...

  10. The etching process of boron nitride by alkali and alkaline earth fluorides under high pressure and high temperature

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Appropriate etch processes of hBN and cBN under HPHT are proposed. • The degree of the crystallization of hBN was decreased. • A special cBN growth mechanism with a triangular unit is proposed. • Plate-shape cBN crystals with large ratio of length to thickness were obtained. • A strategy provides useful guidance for controlling the cBN morphology. - Abstract: Some new etching processes of hexagonal boron nitride (hBN) and cubic boron nitride (cBN) under high pressure and high temperature in the presence of alkali and alkaline earth fluorides have been discussed. It is found that hBN is etched distinctly by alkali and alkaline earth fluorides and the morphology of hBN is significantly changed from plate-shape to spherical-shape. Based on the “graphitization index” values of hBN, the degree of the crystallization of hBN under high pressure and high temperature decreases in the sequence of LiF > CaF2 > MgF2. This facilitates the formation of high-quality cBN single crystals. Different etch steps, pits, and islands are observed on cBN surface, showing the strong etching by alkali and alkaline earth fluorides and the tendency of layer-by-layer growth. A special layer growth mechanism of cBN with a triangular unit has been found. Furthermore, the morphologies of cBN crystals are apparently affected by a preferential surface etching of LiF, CaF2 and MgF2. Respectively, the plate-shape and tetrahedral cBN crystals can be obtained in the presence of different alkali and alkaline earth fluorides

  11. The etching process of boron nitride by alkali and alkaline earth fluorides under high pressure and high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Guo, W., E-mail: guowei1982cry@163.com [College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024 (China); National Key Lab of Superhard Materials, Jilin University, Changchun 130012 (China); Ma, H.A.; Jia, X. [National Key Lab of Superhard Materials, Jilin University, Changchun 130012 (China)

    2014-03-01

    Graphical abstract: - Highlights: Appropriate etch processes of hBN and cBN under HPHT are proposed. The degree of the crystallization of hBN was decreased. A special cBN growth mechanism with a triangular unit is proposed. Plate-shape cBN crystals with large ratio of length to thickness were obtained. A strategy provides useful guidance for controlling the cBN morphology. - Abstract: Some new etching processes of hexagonal boron nitride (hBN) and cubic boron nitride (cBN) under high pressure and high temperature in the presence of alkali and alkaline earth fluorides have been discussed. It is found that hBN is etched distinctly by alkali and alkaline earth fluorides and the morphology of hBN is significantly changed from plate-shape to spherical-shape. Based on the graphitization index values of hBN, the degree of the crystallization of hBN under high pressure and high temperature decreases in the sequence of LiF > CaF{sub 2} > MgF{sub 2}. This facilitates the formation of high-quality cBN single crystals. Different etch steps, pits, and islands are observed on cBN surface, showing the strong etching by alkali and alkaline earth fluorides and the tendency of layer-by-layer growth. A special layer growth mechanism of cBN with a triangular unit has been found. Furthermore, the morphologies of cBN crystals are apparently affected by a preferential surface etching of LiF, CaF{sub 2} and MgF{sub 2}. Respectively, the plate-shape and tetrahedral cBN crystals can be obtained in the presence of different alkali and alkaline earth fluorides.

  12. Pressure effects on hydrogen atoms near the metal plane in the HCP phase of rare-earth metal trihydrides

    Science.gov (United States)

    Tunghathaithip, N.; Pakornchote, T.; Phaisangittisakul, N.; Bovornratanaraks, T.; Pinsook, U.

    2016-04-01

    Rare-earth metal trihydrides, REH3 (RE=Sc, Y, La), in the hcp phase were investigated under high pressure by the ab initio method. We concentrated on the behavior of hydrogen atoms which is affected by pressure. Two-thirds of the hydrogen atoms near the metal plane (Hm) were found to displace away from the metal plane as pressure increases. The trajectory of these squeezed hydrogen atoms is from a site near the metal plane, and moves past the plane of the tetragonal sites, and heads toward the nearest octahedral site. However, the rate of displacement depends on the local environment. LaH3 exhibits the least impediment on the Hm displacement while YH3 and ScH3 exhibit stronger impediment. Furthermore, our calculated Raman and IR active modes are in general agreement with the experimental data. The displacement of Hm can be used to explain the behavior of the Ov peak in Raman spectra, where it exists at low pressure and disappears at higher pressure in YH3 and ScH3.

  13. Cycle studies: material balance estimation in the domain of pressurized water and boiling water reactors. Experimental qualification

    International Nuclear Information System (INIS)

    This study is concerned with the physics of the fuel cycle the aim being to develop and make recommendations concerning schemes for calculating the neutronics of light water reactor fuel cycles. A preliminary study carried out using the old fuel cycle calculation scheme APOLLO1- KAFKA and the library SERMA79 has shown that for the compositions of totally dissolved assemblies from Pressurized Water Reactors (type 17*17) and also for the first time, for Boiling Water Reactor assemblies (type 8*8), the differences between calculation and measurement are large and must be reduced. The integration of the APOLLO2 neutronics code into the fuel cycle calculation scheme improves the results because it can model the situation more precisely. A comparison between APOLLO1 and APOLLO2 using the same options, demonstrated the consistency of the two methods for PWR and BWR geometries. Following this comparison, we developed an optimised scheme for PWR applications using the library CEA86 and the code APOLLO2. Depending on whether the information required is the detailed distribution of the composition of the irradiated fuel or the average composition (estimation of the total material balance of the fuel assembly), the physics options recommended are different. We show that the use of APOLLO2 and the library CEA86 improves the results and especially the estimation of the Pu239 content. Concerning the Boiling Water Reactor, we have highlighted the need to treat several axial sections of the fuel assembly (variation of the void-fraction, heterogeneity of composition). A scheme using Sn transport theory, permits one to obtain a better coherence between the consumption of U235, the production of plutonium and burnup, and a better estimation of the material balance. (author)

  14. Topex data analysis to infer Earth's rotational fluctuations forced by the oceanic response to atmospheric pressure variations

    Science.gov (United States)

    Dey, Nirupam

    The oceanic response to atmospheric pressure variations is a dynamic response that depends on the frequency and spatial scale of the forcing. In this dissertation, the actual oceanic response is derived from TOPEX satellite altimeter sea-surface height (SSH) observations (1993--2004) on a 4 degree latitude, 8 degree longitude grid corrected for tides, winds and annual variations. The SSH data obtained from Jet Propulsion Laboratory (JPL) website is already corrected for tides. The wind correction values are from the ECCO model, which had been obtained from JPL. The wind correction has been modified by a "Darwin" correction to insure mass conservation. To eliminate the large annual signal, which might otherwise overwhelm the analysis, a sinusoid of annual period and a trend for 12 years have been removed at each grid location. Pressure data were downloaded from AER in spherical harmonic form. For each harmonic of forcing, a Wiener filter---generalized for complex time series---is used to isolate that portion of the sea-surface height within each gridbox location due to pressure forcing. The input to the Wiener filter was the corrected SSH time series at that location and the desired output was the pressure harmonic time series. Based on the reduction of the error between the desired and the actual output, this technique appears to be successful (mostly) in isolating that portion of SSH due to individual spherical harmonic pressure coefficients. This pressure-driven portion of the SSH has been used to calculate the associated oceanic currents. Then the combined effect of pressure forced SSH and associated currents on Earth's rotation---polar motion and change in Earth's spin rate---are calculated. The ocean's response showed a spatial and temporal dependence. The currents due to at least some harmonics of forcing showed higher velocities along East-West direction and seemed to be associated with sectorial harmonics. In contrast, the currents along North-South direction showed peak velocities for zonal harmonics. The rotational effects calculated here are mainly due to the pressure-forced SSH and shows frequency dependence. The excitation due to dynamic barometer shows significant departures from the excitation due to inverted barometer.

  15. RADIATION BALANCE

    Science.gov (United States)

    The balance of energy on the earth's surface represents the difference between incoming and outgoing radiation. There are two components in both the incoming and ongoing fractions and are separated by wavelength as shortwave (less than 5 um) and longwave (greater than 5 um). Shortwave radiation or...

  16. Cenosphere formation from heavy fuel oil: a numerical analysis accounting for the balance between porous shells and internal pressure

    KAUST Repository

    Vanteru, Mahendra Reddy

    2016-01-18

    Heavy fuel oil (HFO) as a fuel in industrial and power generation plants ensures the availability of energy at economy. Coke and cenosphere emissions from HFO combustion need to be controlled by particulate control equipment such as electrostatic precipitators, and collection effectiveness is impacted by the properties of these particulates. The cenosphere formation is a function of HFO composition, which varies depending on the source of the HFO. Numerical modelling of the cenosphere formation mechanism presented in this paper is an economical method of characterising cenosphere formation potential for HFO in comparison to experimental analysis of individual HFO samples, leading to better control and collection. In the present work, a novel numerical model is developed for understanding the global cenosphere formation mechanism. The critical diameter of the cenosphere is modelled based on the balance between two pressures developed in an HFO droplet. First is the pressure (Prpf) developed at the interface of the liquid surface and the inner surface of the accumulated coke due to the flow restriction of volatile components from the interior of the droplet. Second is the pressure due to the outer shell strength (PrC) gained from van der Walls energy of the coke layers and surface energy. In this present study it is considered that when PrC ≥ Prpf the outer shell starts to harden. The internal motion in the shell layer ceases and the outer diameter (DSOut) of the shell is then fixed. The entire process of cenosphere formation in this study is analysed in three phases: regression, shell formation and hardening, and post shell hardening. Variations in pressures during shell formation are analysed. Shell (cenosphere) dimensions are evaluated at the completion of droplet evaporation. The rate of fuel evaporation, rate of coke formation and coke accumulation are analysed. The model predicts shell outer diameters of 650, 860 and 1040 µm, and inner diameters are 360, 410 and 430 µm respectively, for 700, 900 and 1100 µm HFO droplets. The present numerical model is validated with experimental results available from the literature. Total variation between computational and experimental results is in the range of 3–7%.

  17. Pressure-induced magnetic transition and sound velocities of Fe3C : implications for carbon in the earth's inner core

    International Nuclear Information System (INIS)

    We have carried out nuclear resonant scattering measurements on 57Fe-enriched Fe3C between 1 bar and 50 GPa at 300 K. Synchrotron Moessbauer spectra reveal a pressure-induced magnetic transition in Fe3C between 4.3 and 6.5 GPa. On the basis of our nuclear resonant inelastic X-ray scattering spectra and existing equation-of-state data, we have derived the compressional wave velocity Vp and shear wave velocity Vs for the high-pressure nonmagnetic phase, which can be expressed as functions of density (ρ): Vp (km/s) = -3.99 + 1.29ρ(g/cm3) and Vs (km/s) = 1.45 + 0.24ρ(g/cm3). The addition of carbon to iron-nickel alloy brings density, Vp and Vs closer to seismic observations, supporting carbon as a principal light element in the Earth's inner core

  18. High-pressure behavior of osmium: An analog for iron in Earth's core

    Science.gov (United States)

    Godwal, B. K.; Yan, J.; Clark, S. M.; Jeanloz, R.

    2012-06-01

    High-resolution x-ray diffraction with diamond-anvil cells, using argon as a quasi-hydrostatic pressure medium, documents the crystal structure and equation of state of osmium to over 60 GPa at room temperature. We find the zero-pressure bulk modulus in fair agreement with other experiments as well as with relativistic electronic band-structure calculations: Osmium is the densest but not the most incompressible element at ambient conditions. We also find no evidence for anomalies in the ratio of unit-cell parameters, c/a, or in the compressibility of osmium as a function of pressure. This is in agreement with other experiments and quantum mechanical calculations but disagrees with recent claims that the electronic structure and equation of state of osmium exhibit anomalies at pressures of ˜15-25 GPa; the discrepancies are may be due to the effects of texturing.

  19. High-pressure elastic properties of major materials of Earth's mantle from first principles

    OpenAIRE

    Karki, B. B.; Stixrude, L.; Wentzcovitch, R. M.

    2001-01-01

    The elasticity of materials is important for our understanding of processes ranging from brittle failure, to flexure, to the propagation of elastic waves. Seismologically revealed structure of the Earth's mantle, including the radial (one-dimensional) profile, lateral heterogeneity, and anisotropy are determined largely by the elasticity of the materials that make up this region. Despite its importance to geophysics, our knowledge of the elasticity of potentially relevant mineral phases at co...

  20. Comparison of Radiation Pressure Perturbations on Rocket Bodies and Debris at Geosynchronous Earth Orbit

    Science.gov (United States)

    Wetterer, C.; Hill, K.; Jah, M.

    2014-09-01

    Recent research has highlighted the need for physically consistent radiation pressure and Bidirectional Reflectance Distribution Function (BRDF) models. This paper seeks to evaluate the impact of BRDF-consistent radiation pressure models compared to changes in the other BRDF parameters. The differences in orbital position arising because of changes in the shape, attitude, angular rates, BRDF parameters, and radiation pressure model are plotted as a function of time for simulated rocket bodies and debris at geo-synchronous orbit (GEO). The initial position and velocity of the space object is kept fixed, and the orbital position difference between a baseline or-bit and the perturbed orbit are plotted as a function of time. This is similar to how the effects of perturbations have been visualized in the past in commonly used astrodynamics references.

  1. High-pressure high-temperature crystal growth of equiatomic rare earth stannides RENiSn and REPdSn

    Science.gov (United States)

    Heymann, Gunter; Heying, Birgit; Rodewald, Ute Ch.; Janka, Oliver; Huppertz, Hubert; Pöttgen, Rainer

    2016-04-01

    The two series of equiatomic rare earth (RE) stannides RENiSn and REPdSn were systematically studied with respect to high-pressure modifications. The normal-pressure (NP) low-temperature (LT) modifications were synthesized by arc-melting and subsequently treated under high-pressure (Pmax=11.5 GPa) and high-temperature (Tmax=1570 K) conditions in a Walker-type multi-anvil press. The pressure and temperature conditions were systematically varied in order to improve the crystallization conditions. The new ZrNiAl-type high-pressure modifications HP-RENiSn (RE=Sc, Y, La, Gd-Lu) and HP-REPdSn (RE=Y, Sm-Dy) were obtained in 80 mg quantities, several of them in X-ray pure form. Some of the REPdSn stannides with the heavy rare earth elements show high-temperature (HT) modifications. The structures of HP-ScNiSn, HP-GdNiSn, HP-DyNiSn (both ZrNiAl-type), NP-YbNiSn, and HT-ErPdSn (both TiNiSi-type) were refined from single crystal diffractometer data, indicating full ordering of the transition metal and tin sites. TiNiSi-type NP-EuPdSn transforms to MgZn2-type HP-EuPdSn: P63/mmc, a=588.5(2), c=917.0(3) pm, wR2=0.0769, 211 F2 values, 11 variables. The structure refinement indicated statistical occupancy of the palladium and tin sites on the tetrahedral network. The X-ray pure high-pressure phases were studied with respect to their magnetic properties. HP-YPdSn is a Pauli paramagnet. The susceptibility data of HP-TbNiSn, HP-DyNiSn, HP-GdPdSn, and HP-TbPdSn show experimental magnetic moments close to the free ion values of RE3+ and antiferromagnetic ordering at low temperature with the highest Néel temperature of 15.8 K for HP-TbPdSn. HP-SmPdSn shows the typical Van Vleck type behavior along with antiferromagnetic ordering at TN=5.1 K. HP-EuPdSn shows divalent europium and antiferromagnetic ordering at 8.9 K followed by a spin reorientation at 5.7 K.

  2. The effect of temperature and pressure on the elastic behaviour of rare-earth phosphate glasses

    International Nuclear Information System (INIS)

    The longitudinal and shear wave velocities propagated in phosphate glasses containing samarium, euporium, neodynium and lantanum have been studied for the first time using the ultrasonic technique from 4.2 to 300 K. The elastic behaviour changes with temperature in an anomalous fashion due to anharmonic vibrational, thermally activated relaxations and the present of two-level system especially at low temperature. The pressure variation of the elastic constants has also been measured and has been used to calculate the elastic Grueneisen parameter for these glasses. For each of these vitreous materials, except the lanthanum phosphates, the bulk and shear moduli decrease under hydrostatic pressure; an indication of acoustic modes softening

  3. The new-generation of solenoid injectors equipped with pressure-balanced pilot valves for energy saving and dynamic response improvement

    International Nuclear Information System (INIS)

    Highlights: • Distinct pilot-valve setups, typical of modern Common Rail injectors, are compared. • The analysis focuses on injector static leakages and the injector dynamic response. • Experimental results are integrated or explained by means of simulation data. - Abstract: A numerical–experimental analysis on a new generation of hydraulically controlled servo solenoid injectors for Euro 6 Diesel engine applications has been carried out. The main innovation of these high-pressure injectors is the replacement of the standard pilot-valve configuration with a pressure-balanced layout. The new setup is aimed at reducing clearance leakages and at improving the dynamic response of the needle to the electrical command. A previously developed advanced one-dimensional code for the simulation of Common Rail injection systems has been adapted to simulate the innovative injectors. In particular, electromagnetic, hydraulic and mechanical submodels have been set up for the pressure-balanced pilot-valve simulation. The validated numerical model of the injector has been applied to investigate the mechanics of the pressure-balanced pilot-valve and the sensitivity of the dynamic response of the needle to some of the innovative pilot-valve layout design parameters. Furthermore, the developed simulation tool has been used to examine the real impact that the replacement of the standard pilot-valve layout with a pressure-balanced one could have on the injected flow-rate performance. The comparative investigation between the standard and the innovative pilot-valve has been completed with an analysis of their experimental static leakages. A comparison has also been made with static leakages measured for hydraulically-controlled servo piezoelectric injectors. Finally, a simple and accurate thermodynamic flow model has been developed to predict static leakages in indirect-acting solenoid and piezoelectric injectors. This model has pointed out the significant dependence of static leakages on temperature and pressure

  4. An Earth Observation Land Data Assimilation System for Data from Multiple Wavelength Domains: Water and Energy Balance Components

    Science.gov (United States)

    Quaife, T. L.; Davenport, I. J.; Lines, E.; Styles, J.; Lewis, P.; Gurney, R. J.

    2012-12-01

    Satellite observations offer a spatially and temporally synoptic data source for constraining models of land surface processes, but exploitation of these data for such purposes has been largely ad-hoc to date. In part this is because traditional land surface models, and hence most land surface data assimilation schemes, have tended to focus on a specific component of the land surface problem; typically either surface fluxes of water and energy or biogeochemical cycles such as carbon and nitrogen. Furthermore the assimilation of satellite data into such models tends to be restricted to a single wavelength domain, for example passive microwave, thermal or optical, depending on the problem at hand. The next generation of land surface schemes, such as the Joint UK Land Environment Simulator (JULES) and the US Community Land Model (CLM) represent a broader range of processes but at the expense of increasing overall model complexity and in some cases reducing the level of detail in specific processes to accommodate this. Typically, the level of physical detail used to represent the interaction of electromagnetic radiation with the surface is not sufficient to enable prediction of intrinsic satellite observations (reflectance, brightness temperature and so on) and consequently these are not assimilated directly into the models. A seemingly attractive alternative is to assimilate high-level products derived from satellite observations but these are often only superficially related to the corresponding variables in land surface models due to conflicting assumptions between the two. This poster describes the water and energy balance modeling components of a project funded by the European Space Agency to develop a data assimilation scheme for the land surface and observation operators to translate between models and the intrinsic observations acquired by satellite missions. The rationale behind the design of the underlying process model is to represent the physics of the water and energy balance in as parsimonious manner as possible, using a force-restore approach, but describing the physics of electromagnetic radiation scattering at the surface sufficiently well that it is possible to assimilate the intrinsic observations made by remote sensing instruments. In this manner the initial configuration of the resulting scheme will be able to make optimal use of available satellite observations at arbitrary wavelengths and geometries. Model complexity can then be built up from this point whilst ensuring consistency with satellite observations.

  5. Impaired standing balance

    OpenAIRE

    Pasma, Jantsje Henrieke

    2015-01-01

    Impaired balance is often seen in elderly and can result in impaired mobility and finally in falling. Failure of compensation strategies or deterioration of underlying systems involved in standing balance could result in impaired balance. To apply targeted interventions to improve balance, it is important to know the underlying cause of impaired balance. In this thesis, it is shown that the underlying systems involved in balance, represented by muscle characteristics, blood pressure and c...

  6. From Science Reserves to Sustainable Multiple Uses beyond Earth orbit: Evaluating Issues on the Path towards Balanced Environmental Management on Planetary Bodies

    Science.gov (United States)

    Race, Margaret

    Over the past five decades, our understanding of space beyond Earth orbit has been shaped by a succession of mainly robotic missions whose technologies have enabled scientists to answer diverse science questions about celestial bodies across the solar system. For all that time, exploration has been guided by planetary protection policies and principles promulgated by COSPAR and based on provisions in Article IX of the Outer Space Treaty of 1967. Over time, implementation of the various COSPAR planetary protection policies have sought to avoid harmful forward and backward contamination in order to ensure the integrity of science findings, guide activities on different celestial bodies, and appropriately protect Earth whenever extraterrestrial materials have been returned. The recent increased interest in extending both human missions and commercial activities beyond Earth orbit have prompted discussions in various quarters about the need for updating policies and guidelines to ensure responsible, balanced space exploration and use by all parties, regardless whether activities are undertaken by governmental or non-governmental entities. Already, numerous researchers and workgroups have suggested a range of different ways to manage activities on celestial environments (e.g, wilderness parks, exclusion zones, special regions, claims, national research bases, environmental impact assessments, etc.). While the suggestions are useful in thinking about how to manage future space activities, they are not based on any systematically applied or commonly accepted criteria (scientific or otherwise). In addition, they are borrowed from terrestrial approaches for environmental protection, which may or may not have direct applications to space environments. As noted in a recent COSPAR-PEX workshop (GWU 2012), there are no clear definitions of issues such as harmful contamination, the environment to be protected, or what are considered reasonable activity or impacts for particular locations—and over what time frames. Likewise, there are no guidelines for how to deal with the potential conflict between economic viability for commercial space activity and the need for reasonable planetary protection measures and standards. Before creating guidelines for particular locations or developing a international environmental regime for blending space exploration and use, it is advisable to have at least have a cursory overview of what lies ahead in the technical, scientific, commercial, environmental and policy realms. To develop such an overview, I undertook a preliminary analysis of the proposed activities, stakeholders, timeframes, and potential environmental impacts anticipated in coming years for robotic and human missions, particularly for the Moon and Mars. Hopefully, this type of information will be useful as the international community works towards updating policies and guidelines for responsible, balanced space exploration and use by all parties.

  7. Improved determination of dynamic balance using the centre of mass and centre of pressure inclination variables in a complete golf swing cycle.

    Science.gov (United States)

    Choi, Ahnryul; Sim, Taeyong; Mun, Joung Hwan

    2016-05-01

    Golf requires proper dynamic balance to accurately control the club head through a harmonious coordination of each human segment and joint. In this study, we evaluated the ability for dynamic balance during a golf swing by using the centre of mass (COM)-centre of pressure (COP) inclination variables. Twelve professional, 13 amateur and 10 novice golfers participated in this study. Six infrared cameras, two force platforms and SB-Clinic software were used to measure the net COM and COP trajectories. In order to evaluate dynamic balance ability, the COM-COP inclination angle, COM-COP inclination angular velocity and normalised COM-COP inclination angular jerk were used. Professional golfer group revealed a smaller COM-COP inclination angle and angular velocity than novice golfer group in the lead/trail direction (P < 0.01). In the normalised COM-COP inclination angular jerk, the professional golfer group showed a lower value than the other two groups in all directions. Professional golfers tend to exhibit improved dynamic balance, and this can be attributed to the neuromusculoskeletal system that maintains balance with proper postural control. This study has the potential to allow for an evaluation of the dynamic balance mechanism and will provide useful basic information for swing training and prevention of golf injuries. PMID:26264189

  8. Metal-silicate partitioning of iodine at high pressures and temperatures: Implications for the Earth's core and 129*Xe budgets

    Science.gov (United States)

    Armytage, Rosalind M. G.; Jephcoat, Andrew P.; Bouhifd, M. A.; Porcelli, Donald

    2013-07-01

    The partition coefficients of iodine Dmet/sil between molten metal and molten silicate were investigated using a Laser Heated Diamond Anvil Cell (LHDAC) at pressures between 2 and 20 GPa and at ~2800 K. No pressure dependence of Dmet/sil was observed within this range, but the composition of the Fe-Ni alloy liquid phase was shown to have an effect. When the metallic liquid was alloyed with S, O and Si, there was an increase in iodine solubility in the metal. Iodine exhibited mildly siderophile behaviour across all the investigated conditions, with Dmet/sil=1.250.65 (2 s.d.) (Fe metal system) and Dmet/sil=4.331.41 (2 s.d.) (Fe-alloy). In conjunction with a revised bulk silicate Earth (BSE) concentration, it is calculated that the core could be a significant reservoir for iodine, with up to 82% of the bulk Earth's iodine budget in the core, depending on the light element content of the metal phase and the process of core formation. The composition of the metal phase appears to have a greater effect on the partitioning and sequestration of iodine than the style of core segregation. As the core likely formed while 129I was still extant, the core can also be a reservoir for radiogenic 129Xe from the decay system 129I-129Xe (T1/2=15.7 Myr). Preliminary modelling indicates that the decay of 129I in the core has the potential to generate radiogenic 129Xe concentrations that are at least two orders of magnitude greater than what has been estimated for the depleted mantle. While this may have a significant impact on the isotopic signatures of the overlying mantle, it is not yet clear how flux from the core fits within the overall picture of mantle noble gas evolution.

  9. Thermal and Pressure Characterization of a Wind Tunnel Force Balance Using the Single Vector System. Experimental Design and Analysis Approach to Model Pressure and Temperature Effects in Hypersonic Wind Tunnel Research

    Science.gov (United States)

    Lynn, Keith C.; Commo, Sean A.; Johnson, Thomas H.; Parker, Peter A,

    2011-01-01

    Wind tunnel research at NASA Langley Research Center s 31-inch Mach 10 hypersonic facility utilized a 5-component force balance, which provided a pressurized flow-thru capability to the test article. The goal of the research was to determine the interaction effects between the free-stream flow and the exit flow from the reaction control system on the Mars Science Laboratory aeroshell during planetary entry. In the wind tunnel, the balance was exposed to aerodynamic forces and moments, steady-state and transient thermal gradients, and various internal balance cavity pressures. Historically, these effects on force measurement accuracy have not been fully characterized due to limitations in the calibration apparatus. A statistically designed experiment was developed to adequately characterize the behavior of the balance over the expected wind tunnel operating ranges (forces/moments, temperatures, and pressures). The experimental design was based on a Taylor-series expansion in the seven factors for the mathematical models. Model inversion was required to calculate the aerodynamic forces and moments as a function of the strain-gage readings. Details regarding transducer on-board compensation techniques, experimental design development, mathematical modeling, and wind tunnel data reduction are included in this paper.

  10. Noninvasive Intracranial Pressure and Tissue Oxygen Measurements for Space and Earth

    Science.gov (United States)

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

    1994-01-01

    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.

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

    OpenAIRE

    Saul Chemonges

    2012-01-01

    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 p...

  12. 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)

    Al Gore

    2007-07-01

    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.

  13. Evaluation of earth pressure on triple multi-face shield tunnel based on centrifuge model tests; Enshin mokei jikken ni yoru yoko sanren shield tunnel no doatsu hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Sugihara, Y.; Igarashi, H.; Fujisaki, K. [Kajima Corp., Tokyo (Japan)

    1995-12-20

    Recently, various needs for the utilization of underground space in urban areas, i.e., those for utilizing underground spaces with complicated cross-section shapes, have been encouraging the research and development of new shield methods. There have been considerations of building many tunnels with various cross-section shapes, such as horizontal double multi-face, horizontal triple multi-face, vertical double multi-face, MMST (multi-micro shield tunnel), and large-section tunnels with combinations of those shapes. The horizontal triple multi-face shield method is a new technique applied to underground railway stations with respect to construction period and safety. Since the horizontal triple multi-face shield tunnel has a laterally flatter shape than the former one circle shield tunnel, it is necessary to verify the validity of design using a usual method of evaluating earth pressure mainly for circle cross-sections. Therefore, the force on segments and deformation of surrounding soil were measured by using a centrifuge model equipment. Consequently, it was found that the earth pressure on horizontal triple multi-face shield segments in sandy ground is between earth pressure as evaluated by Terzaghi`s method and full earth pressure. 5 refs., 14 figs., 3 tabs.

  14. Study of the earth's deep interior and crystallography. X-ray and neutron diffraction experiments under high pressures

    International Nuclear Information System (INIS)

    History of the study of the Earth's deep interior was reviewed. In order to understand Earth's deep interior from the view point of materials science, X-ray diffraction under high pressure and high temperature played very important role. Use of synchrotron radiation dramatically advanced this experimental technique and it is now possible to make precise X-ray study under the P-T conditions corresponding even to the center of the Earth. In order to clarify the behavior of light elements such as hydrogen, however, studies using neutron diffraction are also required. A new neutron beam line dedicated for high-pressure science is constructed at J-PARC and is now ready for use. (author)

  15. 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)

    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

    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)

  16. 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

  17. Effects of supplementing rare earth element cerium on rumen fermentation, nutrient digestibility, nitrogen balance and plasma biochemical parameters in beef cattle.

    Science.gov (United States)

    Lin, S X; Wei, C; Zhao, G Y; Zhang, T T; Yang, K

    2015-12-01

    The objectives of the trial were to investigate the effects of supplementing rare earth element (REE) cerium (Ce) on rumen fermentation, nutrient digestibility, methane (CH4 ) production, nitrogen (N) balance and plasma biochemical parameters in beef cattle. Four Simmental male cattle, aged at 14 months, with initial liveweight of 355 ± 8 kg and fitted with permanent rumen cannulas, were used as experimental animals. The cattle were fed with a total mixed ration (TMR) composed of concentrate mixture and corn silage. Four levels of cerium chloride (CeCl3 ·7H2 O, purity 99.9%), that is 0, 80, 160 and 240 mg CeCl3 /kg DM, were added to basal ration in a 4 × 4 Latin square design. Each experimental period lasted 15 days, of which the first 12 days were for pre-treatment and the last 3 days were for sampling. The results showed that supplementing CeCl3 at 160 or 240 mg/kg DM increased neutral detergent fibre (NDF) digestibility (p < 0.05) and tended to increased acid detergent fibre (ADF) digestibility (p = 0.083). Supplementing CeCl3 at 80, 160 or 240 mg/kg DM decreased the molar ratio of rumen acetate to propionate linearly (p < 0.05). Supplementing CeCl3 at 160 or 240 mg/kg DM decreased total N excretion, urinary N excretion and increased N retention (p < 0.05), increased excretion of total urinary purine derivatives (PD) (p < 0.05) and decreased CH4 /kg DMI (p < 0.05). In conclusion, supplementing CeCl3 at 160 or 240 mg/kg DM in the ration of beef cattle increased the digestibility of NDF, decreased the molar ratio of rumen acetate to propionate, increased N retention and microbial N flow and decreased CH4 /kg DMI. PMID:25787979

  18. Defect and intra-4f luminescence of rare earth doped group-III nitrides synthesized by high pressure high temperature method

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Sven; Vetter, Ulrich; Hofsaess, Hans [Georg-August-Universitaet Goettingen (Germany). II. Physikalisches Institut; Taniguchi, Takashi [National Institute for Materials Science, Namiki, Tsukuba, Ibaraki (Japan)

    2010-07-01

    Cubic boron nitride (c-BN) and AlN exhibit the largest band gaps among all group-III nitrides with 6.2 and 6.0 eV, respectively. Both materials posses the ability for optoelectonic building blocks which can operate at high temperatures, high power, high frequencies and under extreme chemical conditions. The intensive and narrow intra-4f luminescence of rare earth doped c-BN and AlN crystals could be employed for laser diodes or in optical communication technology. Rare earth doped c-BN and AlN crystals were synthesized via the high temperature high pressure method, with temperatures and pressures between 1450-1620 C and 4.5-6.3 GPa, respectively. Ba{sub 3}B{sub 2}N{sub 4} and Li{sub 3}AlN{sub 2} were used as solvents with addition of rare earth fluorides as source material for the synthesis of c-BN and AlN, respectively. The luminescence of rare earth doped c-BN and AlN is a superposition of different defect transitions of the host material and intra-4f transitions of the rare earth dopant ion. Intrinsic defects as well as impurity defect complexes serve as origin for various defect bands in c-BN and AlN.

  19. 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

  20. MEMS Technology Sensors as a More Advantageous Technique for Measuring Foot Plantar Pressure and Balance in Humans

    OpenAIRE

    Clara Sanz Morère; Łukasz Surażyński; Ana Rodrigo Pérez-Tabernero; Erkki Vihriälä; Teemu Myllylä

    2016-01-01

    Locomotor activities are part and parcel of daily human life. During walking or running, feet are subjected to high plantar pressure, leading sometimes to limb problems, pain, or foot ulceration. A current objective in foot plantar pressure measurements is developing sensors that are small in size, lightweight, and energy efficient, while enabling high mobility, particularly for wearable applications. Moreover, improvements in spatial resolution, accuracy, and sensitivity are of interest. Sen...

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

    OpenAIRE

    Farzin Salmasi; Behnam Mansuri

    2013-01-01

    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,...

  2. 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, β = 93.58(3) for Tb2(BO3)F3, a = 16.225(3), b = 6.160(2), c = 8.307(2) A, β = 93.64(3) for Dy2(BO3)F3, and a = 16.189(3), b = 6.124(2), c = 8.282(2) A, β = 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.)

  3. Shp2 signaling in POMC neurons is important for leptin's actions on blood pressure, energy balance, and glucose regulation

    OpenAIRE

    do Carmo, Jussara M; da Silva, Alexandre A.; Ebaady, Sabira E.; Sessums, Price O.; Abraham, Ralph S.; Elmquist, Joel K.; Lowell, Bradford B; Hall, John E

    2014-01-01

    Previous studies showed that Src homology-2 tyrosine phosphatase (Shp2) is an important regulator of body weight. In this study, we examined the impact of Shp2 deficiency specifically in proopiomelanocortin (POMC) neurons on metabolic and cardiovascular function and on chronic blood pressure (BP) and metabolic responses to leptin. Mice with Shp2 deleted in POMC neurons (Shp2/Pomc-cre) and control mice (Shp2flox/flox) were implanted with telemetry probes and venous catheters for measurement of...

  4. 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)

    International Nuclear Information System (INIS)

    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)

  5. 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)

    Dey, N.; Dickman, S. R.

    2013-12-01

    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.

  6. Immobilization-induced increases of systolic blood pressure and dysregulation of electrolyte balance in ethanol-treated rats.

    Science.gov (United States)

    Yasmin, Farzana; Haque, Zeba; Ikram, Huma; Haleem, Darakhshan Jabeen

    2015-07-01

    Clinical and experimental studies revealed that alcohol drinking and life event stresses are predisposing factors to hypertension. Intra and extra cellular levels of electrolytes may play important role in the pathogenesis and treatment of hypertension. Dietary intake of sodium, potassium, calcium and magnesium is suggested to have a role in the regulation of blood pressure. The present study was designed to monitor the effects of acute exposure to 2h immobilization stress and ethanol administration at a dose of 2.5 g/kg body weight (i.p.) and combined effect of acute administration of ethanol and immobilization stress on systolic blood pressure (SBP), intraerythrocyte, serum and tissue electrolytes in rats. Results showed that acute exposure to 2h immobilization increased SBP, intraerythrocyte sodium and decreased intraerythrocyte potassium in water as well as in ethanol injected rats. The concentration of Na⁺ and Ca²⁺ increased while that of K⁺ and Mg²⁺ decreased in the heart and kidney tissue. Ethanol administration also increased Na⁺ and Ca²⁺ levels and decreased K⁺ and Mg²⁺ levels in the heart and kidney tissue. Restraint stress decreased serum levels of Na⁺, K⁺, Ca²⁺, P, and Cl⁻ and increased serum Mg²⁺, glucose and haematocrit. Ethanol administration also decreased serum levels of Na⁺, K⁺, Ca²⁺, P, and Cl⁻ and increased serum Mg²⁺, glucose and haematocrit. The effects of ethanol and stress on the changes of blood and tissues electrolytes were additive and may be involved in the greater occurrence of hypertension in alcoholics. Our results suggested an important role of intra and extra cellular electrolytes in both stress and ethanol-induced hypertension. The findings may help to develop strategies for the treatment of hypertension in alcoholics. PMID:26142527

  7. Effect of hydrostatic pressure on the elastic properties of some rare earth-iron Laves phase compounds

    International Nuclear Information System (INIS)

    The pressure dependence of the Young's and shear moduli of RFe2(R=Sm, Gd, Tb, Dy, Ho and Er) has been determined at room temperature in the pressure range between 0 and 1 GPa. The elastic moduli of GdFe2, DyFe2, HoFe2 and ErFe2 show a moderate increase with increasing hydrostatic pressure. However, the elastic moduli of SmFe2 and TbFe2 exhibit an initially drastic increase followed by a high, and linear, pressure dependence. From the pressure and temperature derivatives of the elastic moduli of these RFe2 Laves phase compounds the equations of state and the Grueneisen parameters have been derived. The variation of the elastic properties with hydrostatic pressure is compared with the effect of magnetic fields. The anomalous behavior of SmFe2 and TbFe2 is discussed. (author)

  8. Earth materials and earth dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, K; Shankland, T. [and others

    2000-11-01

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

  9. Features and regularities in behavior of thermoelectric properties of rare-earth, transition, and other metals under high pressure up to 20 GPa

    International Nuclear Information System (INIS)

    We report results of systematic investigations of the thermoelectric properties of a number of rare-earth metals, transition metals, and other metals under high pressure up to 20 GPa at room temperature. We studied an effect of applied pressure on the Seebeck effect of scandium (Sc), yttrium (Y), lanthanum (La), europium (Eu), ytterbium (Yb), iron (Fe), manganese (Mn), chromium (Cr), gold (Au), tin (Sn), and CeNi alloy. We found that the high-pressure behavior of the thermopower of three rare-earth metals, namely, Sc, Y, and La, follows a general trend that has been established earlier in lanthanides, and addressed to a s → d electron transfer. Europium and ytterbium, on the contrary, showed a peculiar high-pressure behavior of the thermopower with peaks at near 0.7–1 GPa for Eu and 1.7–2.5 GPa for Yb. Chromium, manganese, and tin demonstrated a gradual and pronounced lowering of the absolute value of the thermopower with pressure. Above 9–11 GPa, the Seebeck coefficients of Mn and Sn were inverted, from n- to p-type for Mn and from p- to n-type for Sn. The Seebeck effect in iron was rather high as ∼16 μV/K and weakly varied with pressure up to ∼11 GPa. Above ∼11 GPa, it started to drop dramatically with pressure to highest pressure achieved 18 GPa. Upon decompression cycle the thermopower of iron returned to the original high values but demonstrated a wide hysteresis loop. We related this behavior in iron to the known bcc (α-Fe) → hcp (ε-Fe) phase transition, and proposed that the thermoelectricity of the α-Fe phase is mainly contributed by the spin Seebeck effect, likewise, the thermoelectricity of the ε-Fe phase—by the conventional diffusion thermopower. We compare the pressure dependencies of the thermopower for different groups of metals and figure out some general trends in the thermoelectricity of metals under applied stress

  10. Experimental and Numerical Study of the Effect of PET Recycling Admixtures on Pore Water Pressure and Output Discharge in Homogeneous Earth Dams.

    Directory of Open Access Journals (Sweden)

    Reza Ahmad Zadeh Touri

    2015-01-01

    Full Text Available This study analytically and experimentally investigates the leakage in homogenous earth dam (clay reinforced by recycled PET. First, the effect of PET addition on permeability of clay in geotechnical laboratory is evaluated, according to the results of first step, a physical model of homogenous earth dam is prepared in laboratory flume, both in PETs or without PETs and measured the water height in dam body using piezometers installed on flume body and also leakage discharge was calculated. Third, phreatic line formed in the body of dam and the pore pressure of it was analyzed regarding the first and second phases. The impact of output discharge reduction on dam stability was also studied in software; PET addition impact on output discharge reduction was 23.14%. Discharge reduction lead to increase of dam stability.

  11. 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)

    Farzin Salmasi

    2013-05-01

    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.

  12. Separation of rare earths from uranium by anion exchange with pre-exclusion of loading solution under pressure and determination by ICP-MS

    International Nuclear Information System (INIS)

    An intermittently pressurized anion exchange column is used for separation of trace rare earth elements (REES) from uranium before ICP-MS measurements. The whole separation can be completed within 20 min. The recoveries for all REES are in the range of 96%-106%. Comparing with previous methods, this technique consumes less chemicals and produces less waste. The applicability and reliability of this procedure is demonstrated by the good accordance between results determined by this method and the recommended values for REES in a standard reference material (GBW04207). It is proved that this method would be useful for analysis of trace REES impurities in uranium metal and its oxides

  13. Universal behavior of chalcogenides of rare-earth metals in the transition to a state with intermediate valence at high pressures

    Energy Technology Data Exchange (ETDEWEB)

    Tsiok, O. B.; Khvostantsev, L. G.; Brazhkin, V. V., E-mail: brazhkin@hppi.troitsk.ru [Russian Academy of Sciences, Vereshchagin Institute of High-Pressure Physics (Russian Federation)

    2015-06-15

    Precision measurements of resistivity, thermopower, and volume are performed for TmS, TmSe, and TmTe under a hydrostatic pressure up to 8 GPa. Comparison of the transport properties and volume of TmTe and SmTe in the valence transition region demonstrates a complete analogy up to quantitative coincidence. It is shown that the thermopower of all thulium and samarium chalcogenides in the lattice collapse region and in subsequent rearrangement of the electron spectrum in a wide range of pressures follow a universal dependence corresponding the passage of the Fermi level through the peak of the density of states (DOS). The results are considered in the context of ideas about the exciton nature of the intermediate valence in chalcogenides of rare-earth metals.

  14. Universal behavior of chalcogenides of rare-earth metals in the transition to a state with intermediate valence at high pressures

    Science.gov (United States)

    Tsiok, O. B.; Khvostantsev, L. G.; Brazhkin, V. V.

    2015-06-01

    Precision measurements of resistivity, thermopower, and volume are performed for TmS, TmSe, and TmTe under a hydrostatic pressure up to 8 GPa. Comparison of the transport properties and volume of TmTe and SmTe in the valence transition region demonstrates a complete analogy up to quantitative coincidence. It is shown that the thermopower of all thulium and samarium chalcogenides in the lattice collapse region and in subsequent rearrangement of the electron spectrum in a wide range of pressures follow a universal dependence corresponding the passage of the Fermi level through the peak of the density of states (DOS). The results are considered in the context of ideas about the exciton nature of the intermediate valence in chalcogenides of rare-earth metals.

  15. Anorthite: Thermal equation of state to high pressures. [for comparison with Earth interior and cratering properties of lunar surface

    Science.gov (United States)

    Jeanloz, R.; Ahrens, T. J.

    1979-01-01

    The shock wave (Hugoniot) data on single crystal and porous anorthite (CaAl2Si208) to pressures of 120 GPa are presented. These data are inverted to yield high pressure values of the Grueneisen parameter, adiabatic bulk modulus, and coefficient of thermal expansion over a broad range of pressures and temperatures which in turn are used to reduce the raw Hugoniot data and construct an experimentally based, high pressure thermal equation of state for anorthite. The hypothesis that higher order anharmonic contributions to the thermal properties decrease more rapidly upon compression than the lowest order anharmonicities is supported. The properties of anorthite corrected to lower mantle conditions show that although the density of anorthite is comparable to that of the lower most mantle, its bulk modulus is considerably less, hence making enrichment in the mantle implausible except perhaps near its base.

  16. Carbonate stability in the earth's mantle - A vibrational spectroscopic study of aragonite and dolomite at high pressures and temperatures

    Science.gov (United States)

    Kraft, Susan; Knittle, Elise; Williams, Quentin

    1991-01-01

    The structural changes of aragonite and dolomite taking place at high pressures and temperatures were investigated by measuring the Raman spectra of these materials to pressures of 23 and 28 GPa (generated in a diamond anvil cell), respectively; in addition, the IR spectra of aragonite were measured to 40 GPa. The spectroscopic data demonstrated that, at 300 K, dolomite and aragonite samples were stable to pressures of 28 and 41 GPa, respectively. No phase transitions were observed following heating of aragonite and dolomite to temperatures of 2000 K and 800 K, respectively. The mode Grueneisen parameters indicate that the carbonate group in these two minerals is relatively insensitive to pressure, with the dominant compaction mechanism being the compression of the Ca and Mg polyhedra.

  17. Repetitive sit-to-stand training with the step-foot position on the non-paretic side, and its effects on the balance and foot pressure of chronic stroke subjects.

    Science.gov (United States)

    Kim, Kyung; Kim, Young Mi; Kang, Dong Yeon

    2015-08-01

    [Purpose] This study aimed to improve the asymmetrical weight-bearing ratio by applying repetitive sit-to-stand training methods that feature a step-foot position to the paretic-side foot of hemiplegic patients; it sought also to provide the information needed to apply weight-bearing and balance training to hemiplegic patients. [Subjects and Methods] The subjects were divided into two groups: a spontaneous group and a step group. They all performed repetitive sit-to-stand training five times per week for a total of six weeks. The Biodex Balance System, TUG, and 5XSST were used to measure the static and dynamic standing balance of each patient. A foot mat system was used to measure foot pressure. [Results] In the balance measurements, differences in the Overall index, Ant-post index, Med-lat index, Fall risk index, TUG, and 5XSST after training was significantly different between the two study groups. In evaluating foot pressure measurements, we found that the COP (Ant-post), Peak pressure: hind foot, and Contact area: hind foot measurements significantly differed between the groups after the training. [Conclusion] Repetitive sit-to-stand training that involves positioning the non-paretic leg upward can be considered a significant form of training that improves the symmetric posture adjustment and balance of hemiplegic patients following a stroke. PMID:26357448

  18. Magnesite formation from MgO and CO2 at the pressures and temperatures of Earth's mantle

    Energy Technology Data Exchange (ETDEWEB)

    Scott, Henry P.; Doczy, Vincent M.; Frank, Mark R.; Hasan, Maggie; Lin, Jung-Fu; Yang, Jing [NIU; (Indiana); (Texas)

    2013-08-02

    Magnesite (MgCO3) is an important phase for the carbon cycle in and out of the Earth’s mantle. Its comparably large P-T stability has been inferred for several years based on the absence of its decomposition in experiments. Here we report the first experimental evidence for synthesis of magnesite out of its oxide components (MgO and CO2) at P-T conditions relevant to the Earth’s mantle. Magnesite formation was observed in situ using synchrotron X-ray diffraction, coupled with laser-heated diamond-anvil cells (DACs), at pressures and temperatures of Earth’s mantle. Despite the existence of multiple high-pressure CO2 polymorphs, the magnesite-forming reaction was observed to proceed at pressures ranging from 5 to 40 GPa and temperatures between 1400 and 1800 K. No other pressure-quenchable materials were observed to form via the MgO + CO2 = MgCO3 reaction. This work further strengthens the notion that magnesite may indeed be the primary host phase for oxidized carbon in the deep Earth.

  19. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Bacchiani, M.; Medich, C.; Rigamonti, M. [SIET S.p.A. Piacenza (Italy)] [and others

    1995-09-01

    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}2{close_quotes} Cold Leg (CL) to Core Make-up Tank (CMT) pressure balance line break{close_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.

  1. 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 ΔIW-2. For Mars, based on a core segregation process around ΔIW-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 ΔIW-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)

  2. Balance Problems

    Science.gov (United States)

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

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

    OpenAIRE

    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

    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 marks the onset of a...

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Kieffer, S.W. [Univ. of British Columbia, British Columbia (Canada)

    1995-09-08

    Volcanic eruptions of gassy magmas on Earth, Venus, and Mars produce plumes with markedly different fluid dynamics regimes. In large part the differences are caused by the differing atmospheric pressures and ratios of volcanic vent pressure to atmospheric pressure. For each of these planets, numerical simulations of an eruption of magma containing 4 weight percent gas were run on a workstation. On Venus the simulated eruption of a pressure-balanced plume formed a dense fountain over the vent and continuous pyroclastic flows. On Earth and Mars, simulated pressure-balanced plumes produced ash columns, ash falls, and possible small pyroclastic flows. An overpressured plume, illustrated for Mars, exhibited a complex supersonic velocity structure and internal shocks. 31 refs., 7 figs., 2 tabs.

  6. 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)

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

    2014-03-07

    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.

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

    Science.gov (United States)

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

    1988-01-01

    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.

  8. 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)

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

    2012-12-01

    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.

  9. Thermal conductivity of H2O-CH3OH mixtures at high pressures: Implications for the dynamics of icy super-Earths outer shells

    Science.gov (United States)

    Hsieh, Wen-Pin; Deschamps, Frdric

    2015-10-01

    Thermal conductivity of H2O-volatile mixtures at extreme pressure-temperature conditions is a key factor to determine the heat flux and profile of the interior temperature in icy bodies. We use time domain thermoreflectance and stimulated Brillouin scattering combined with diamond anvil cells to study the thermal conductivity and sound velocity of water (H2O)-methanol (CH3OH) mixtures to pressures as high as 12 GPa. Compared to pure H2O, the presence of 5-20 wt % CH3OH significantly reduces the thermal conductivity and sound velocity when the mixture becomes ice VI-CH3OH and ice VII-CH3OH phases at high pressures, indicating that the heat transfer is hindered within the icy body. We then apply these results to model the heat transfer through the icy mantles of super-Earths, assuming that these mantles are animated by thermal convection. Our calculations indicate that the decrease of thermal conductivity due to the presence of 10 wt % CH3OH induces a twofold decrease of the power transported by convection.

  10. 3-D force-balanced magnetospheric configurations

    Directory of Open Access Journals (Sweden)

    S. Zaharia

    2004-01-01

    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 ψ 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

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

    Science.gov (United States)

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

    2013-01-01

    The ability of terrestrial microorganisms to grow in the near-surface environment of Mars is of importance to the search for life and protection of that planet from forward contamination by human and robotic exploration. Because most water on present-day Mars is frozen in the regolith, permafrosts are considered to be terrestrial analogs of the martian subsurface environment. Six bacterial isolates were obtained from a permafrost borehole in northeastern Siberia capable of growth under conditions of low temperature (0 °C), low pressure (7 mbar), and a CO2-enriched anoxic atmosphere. By 16S ribosomal DNA analysis, all six permafrost isolates were identified as species of the genus Carnobacterium, most closely related to C. inhibens (five isolates) and C. viridans (one isolate). Quantitative growth assays demonstrated that the six permafrost isolates, as well as nine type species of Carnobacterium (C. alterfunditum, C. divergens, C. funditum, C. gallinarum, C. inhibens, C. maltaromaticum, C. mobile, C. pleistocenium, and C. viridans) were all capable of growth under cold, low-pressure, anoxic conditions, thus extending the low-pressure extreme at which life can function. PMID:23267097

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

    Science.gov (United States)

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

    2013-01-01

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

  13. 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)

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

    1997-05-27

    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.

  14. Tunnel construction work under high earth pressure and springwater flouing condition. Construction details of a pioneer drift for Hida tunnel, Tokai-Hokuriku expressway

    International Nuclear Information System (INIS)

    Tunnels such as those planned for the International Linear Collider (ILC) Project are long and narrow structures under the ground. In the construction of these tunnels, various circumstances sometimes restrict the initial surveys from obtaining detailed geological information. In Japan, complicated geological structure composed of discontinuous plate tectonics can be found. Therefore, in order to ensure effective construction planning and execution, it is important that precise geological information be acquired through initial survey and then verified with investigation results during the construction. Hida Tunnel of Tokai Hokuriku Expressway, which is 10.7 km long and took more than 11 years to finish, is the second longest highway tunnel in Japan. The tunnel was constructed using the TBM method in the beginning. Later the method was replaced with NATM because of hostile construction conditions, which include existences of springwater and massive earth pressure due to more than 1000 m of earth loading on top, as well as weak zones consisted of active faults. This paper reports on the geological structure and construction details of a pioneer drift for Hida Tunnel, which was completed by overcoming complicated and poor geological conditions. At the same time, we will mention the ideal method of the geological survey in future ILC plan. (author)

  15. 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)

    Saul Chemonges

    2012-12-01

    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.

  16. 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)

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

    2014-01-01

    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

  17. Indoor seismology by probing the Earth's interior by using sound velocity measurements at high pressures and temperatures

    International Nuclear Information System (INIS)

    The adiabatic bulk (K S) and shear (G) moduli of mantle materials at high pressure and temperature can be obtained directly by measuring compressional and shear wave velocities in the laboratory with experimental techniques based on physical acoustics. We present the application of the current state-of-the-art experimental techniques by using ultrasonic interferometry in conjunction with synchrotron x radiation to study the elasticity of olivine and pyroxenes and their high-pressure phases. By using these updated thermoelasticity data for these phases, velocity and density profiles for a pyrolite model are constructed and compared with radial seismic models. We conclude that pyrolite provides an adequate explanation of the major seismic discontinuities at 410- and 660-km depths, the gradient in the transition zone, as well as the velocities in the lower mantle, if the uncertainties in the modeling and the variations in different seismic models are considered. The characteristics of the seismic scaling factors in response to thermal anomalies suggest that anticorrelations between bulk sound and shear wave velocities, as well as the large positive density anomalies observed in the lower mantle, cannot be explained fully without invoking chemical variations

  18. Potassium-bearing Iron-Nickel Sulfides in Nature and High-Pressure Experiments: Geochemical Consequences of Potassium in the Earth's Core

    Science.gov (United States)

    Keshav, S.; Corgne, A.; McDonough, W. F.; Fei, Y.

    2005-01-01

    Introduction: Potassium (K) as a large ion lithophile element has dominantly been concentrated in the Earth s crust and the mantle through differentiation, and in the form of K-40 contributes to the planet s heat budget. However, whether or not K also enters core-forming phases, has been debated for over three decades. Arguments favoring entry of K in the core are based on: (1) K-sulfide (with Fe, Ni, Cu, Na, and Cl; djerfisherite) found in highly reduced enstatite chondrites (or aubrites, enstatite achondrites); (2) demonstration that K, owing to an s-d electronic switch at high-pressure, exhibits transition- element like character, (3) solubility of measurable K in Fe-Ni-S liquids at high pressure, temperature conditions, and (4) models of cooling of the core that seem to require, besides convection, some form of radioactivity, and thus lending support to the experimental work. In this contribution, we assess the effect of sequestering K in the core, as it is perhaps an element that is a key to reconciling geochemistry, paleomagnetism, accretion, and thermal evolution models for the planet.

  19. Energy balance and stability

    International Nuclear Information System (INIS)

    The energy balance of the outer atmospheres of solarlike stars is discussed. The energy balance of open coronal regions is considered, discussing the construction and characteristics of models of such regions in some detail. In particular, the temperature as a function of height is considered, as are the damping length dependence of the global energy balance in the region between the base of the transition region and the critical point, and the effects of changing the amount of coronal heating, the stellar mass, and the stellar radius. Models of coronal loops are more briefly discussed. The chromosphere is then included in the discussion of the energy balance, and the connection between global energy balance and global thermal stability is addressed. The observed positive correlations between the chromospheric and coronal energy losses and the pressure of the transition region is qualitatively explained

  20. 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)

    Buelow, Nicholas Lee

    2005-08-01

    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.

  1. 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

    Frueh, Carolin; Kelecy, Thomas

    2013-01-01

    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...

  2. Balance Problems

    Science.gov (United States)

    ... depends on the underlying causes. How Common are Balance Problems? Nearly eight million adults of all ages in the United States report ... adults are affected. In adults over age 65, balance problems are linked to falls. One-third of adults in this age group and over half of ...

  3. Microstructure and property evaluation of high-pressure die-cast Mg–La–rare earth (Nd, Y or Gd) alloys

    International Nuclear Information System (INIS)

    Highlights: • Different rare earth elements have remarkably different effects on Mg castability. • For the addition of each RE element, the alloy castability follows a unique pattern. • The effects of RE elements on the castability can be modelled. - Abstract: Microstructure, castability and tensile properties were investigated in high-pressure die-cast Mg–La–Nd, Mg–La–Y and Mg–La–Gd alloy series, with a constant La concentration at approximately 2.5 wt.% and the concentrations of Nd, Y or Gd were varied. All three alloy series had a dendritic microstructure with a Mg–La-rich eutectic with increasing Nd, Y or Gd content and containing a Mg12RE intermetallic phase. The morphology of the eutectic at ternary alloying additions of equal to or less than 1.0 wt.% was lamellar but became increasingly divorced at higher ternary concentrations. This was however more obvious in Mg–La–Y and Mg–La–Gd than Mg–La–Nd alloys. The hot tearing susceptibility in all three alloy series increased markedly with even micro-alloying additions of Nd, Y or Gd, and began to decrease again in alloys with more than 0.5 wt.% Y or 1.0 wt.% Gd, but did not decrease significantly for Mg–La–Nd. A model using the temperature–fraction solid curves as input parameters was used to estimate hot tearing susceptibility for Mg–La–Nd alloys. Tensile testing at room temperature showed that Mg–La–Nd alloy series had higher 0.2% proof stress and lower elongation to failure than either the Mg–La–Y or the Mg–La–Gd alloy series for Nd concentrations greater than 1 wt.% due to a greater effectiveness of grain boundary reinforcement

  4. Balance Problems

    Science.gov (United States)

    ... an older adult's life. BPPV (Benign Paroxysmal Positional Vertigo) There are many types of balance disorders. One of the most common is benign paroxysmal positional vertigo, or BPPV. In BPPV, you experience a brief, ...

  5. Intra-session test-retest reliability of magnitude and structure of center of pressure from the Nintendo Wii Balance Board™ for a visually impaired and normally sighted population.

    Science.gov (United States)

    Jeter, Pamela E; Wang, Jiangxia; Gu, Jialiang; Barry, Michael P; Roach, Crystal; Corson, Marilyn; Yang, Lindsay; Dagnelie, Gislin

    2015-02-01

    Individuals with visual impairment (VI) have irreparable damage to one of the input streams contributing to postural stability. Here, we evaluated the intra-session test-retest reliability of the Wii Balance Board (WBB) for measuring Center of Pressure (COP) magnitude and structure, i.e. approximate entropy (ApEn) in fourteen legally blind participants and 21 participants with corrected-to-normal vision. Participants completed a validated balance protocol which included four sensory conditions: double-leg standing on a firm surface with eyes open (EO-firm); a firm surface with eyes closed (EC-firm); a foam surface with EO (EO-foam); and a foam surface with EC (EC-foam). Participants performed the full balance protocol twice during the session, separated by a period of 15min, to determine the intraclass correlation coefficient (ICC). Absolute reliability was determined by the standard error of measurement (SEM). The minimal difference (MD) was estimated to determine clinical significance for future studies. COP measures were derived from data sent by the WBB to a laptop via Bluetooth. COP scores increased with the difficulty of sensory condition indicating WBB sensitivity (all pbalance impairment among VI persons. PMID:25555361

  6. 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)

    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

    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.)

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

    International Nuclear Information System (INIS)

    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. - Graphical abstract: The structure of RExTa2O5+1.5x and its HRTEM image (“A” arrows show empty channel, “B” arrows show filled channel). - Highlights: • We synthesized new tantalates of RE under high pressure high temperature conditions. • RE atoms replace water molecules in the channels of the structure. • Aqueous as well as anhydrous tantalates were obtained. • Highly charged cations RE+3 compress the unit cell decreasing RE–O distances

  8. Experimental and Numerical Study of the Effect of PET Recycling Admixtures on Pore Water Pressure and Output Discharge in Homogeneous Earth Dams.

    OpenAIRE

    Reza Ahmad Zadeh Touri; Somayyeh Pourbakhshian; Majid Pouraminian

    2015-01-01

    This study analytically and experimentally investigates the leakage in homogenous earth dam (clay) reinforced by recycled PET. First, the effect of PET addition on permeability of clay in geotechnical laboratory is evaluated, according to the results of first step, a physical model of homogenous earth dam is prepared in laboratory flume, both in PETs or without PETs and measured the water height in dam body using piezometers installed on flume body and also leakage discharge was calculated. T...

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

    Directory of Open Access Journals (Sweden)

    Lissette Ruiz-Tagle

    2011-12-01

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

  10. Balance System

    Science.gov (United States)

    1988-01-01

    TherEx Inc.'s AT-1 Computerized Ataxiameter precisely evaluates posture and balance disturbances that commonly accompany neurological and musculoskeletal disorders. Complete system includes two-strain gauged footplates, signal conditioning circuitry, a computer monitor, printer and a stand-alone tiltable balance platform. AT-1 serves as assessment tool, treatment monitor, and rehabilitation training device. It allows clinician to document quantitatively the outcome of treatment and analyze data over time to develop outcome standards for several classifications of patients. It can evaluate specifically the effects of surgery, drug treatment, physical therapy or prosthetic devices.

  11. 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)

    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

    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)

  12. 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)

  13. Balancing Risk

    DEFF Research Database (Denmark)

    Nygaard, Lene; Rossen, Camilla Blach; Buus, Niels

    2015-01-01

    This study explored how eight pregnant women diagnosed with depression managed the decision whether or not to take antidepressants during pregnancy. In total, 11 interviews were conducted and analysed by means of constructivist grounded theory. The major category constructed was Balancing risk...

  14. Balancing Eggs

    Science.gov (United States)

    Mills, Allan

    2014-01-01

    Theory predicts that an egg-shaped body should rest in stable equilibrium when on its side, balance vertically in metastable equilibrium on its broad end and be completely unstable on its narrow end. A homogeneous solid egg made from wood, clay or plastic behaves in this way, but a real egg will not stand on either end. It is shown that this…

  15. The balance of frictional heat production, thermal pressurization, and slip resistance on exhumed mid-crustal faults (Adamello batholith, Southern Italian Alps)

    Science.gov (United States)

    Griffith, W. A.; di Toro, G.; Pollard, D. D.

    2005-12-01

    Exhumed faults cutting the Adamello batholith (Italian Alps) were active ca. 30 Ma at seismogenic depths of 9-11 km. The faults "exploited preexisting joints and can be classified into three groups containing: (A) only cataclasite (a fault rock with no evidence of melting), (B) cataclasite and pseudotachylyte (solidified friction-induced melts produced during earthquakes), and (C) only pseudotachylyte. The majority of pseudotachylyte-bearing faults in this outcrop overprint pre-existing cataclasites (Type B), suggesting a transition between slip styles; however, some faults exhibiting pseudotachylyte and no cataclasite (Type C) display evidence of only one episode of slip. Faults of Type A never transitioned to frictional melting. We attempt to compare faults of type A, B, and C in terms of a simple one-dimensional thermo-mechanical model introduced by Lachenbruch (1980) describing the interaction between frictional heating, pore fluid pressure, and shear resistance during slip. The interaction of these three parameters influences how much elastic strain is relieved during an earthquake. For a conceptualized fault zone of finite thickness, the interplay between the shear resistance, heat production, and pore fluid pressure can be expressed as a non-linear partial differential equation relating these processes to the strain rate acting within a fault zone during a slip event. The behavior of fault zones in terms of these coupled processes during an earthquake depends on a number of parameters, such as thickness of the principal slipping zone, net coseismic slip, fault rock permeability and thermal diffusivity. Ideally, the governing equations should be testable on real fault zones if the requisite parameters can be measured or reasonably estimated. The model can be further simplified if the peak temperature reached during slip and the coseismic slip rate can be constrained. The contrasting nature of slip on the three Adamello fault types highlights (1) important differences between slip processes on cataclastic and melt-producing faults at depth and (2) some limitations of applicability of such models to real faults.

  16. First-Principles Studies of Pressure-Induced Structural and Insulator-To Transitions in Alkaline-Earth Dicarbides MC2 (M = Ca, Sr and Ba)

    Science.gov (United States)

    Jiang, Li-Na

    2013-12-01

    Pressure-induced phase transitions in MC2 (M = Ca, Sr and Ba) are investigated by using the first-principles plane wave pseudopotential method within the generalized gradient approximation. The first-order phase transition from tetragonal phase (CaC2-type, space group I4/mmm) to rhombohedral (CsCl-type, space group R/line{3}m) structure is predicted to occur at 22.2, 10.0 and 3.6 GPa, respectively, and transition pressure point of BaC2 agrees well with recent theoretical works. Based on the electronic analysis, the ionic Ca-C bond character becomes stronger with increasing pressure in both I4/mmm and R/line{3}m phases. In particular, there will occur a transition from insulator to metal with increasing pressure due to the reason that the calculated band gap gets narrower and finally closes at some high pressure.

  17. Stationkeeping of the First Earth-Moon Libration Orbiters: The ARTEMIS Mission

    Science.gov (United States)

    Folta, David; Woodard, Mark; Cosgrove, D.

    2011-01-01

    Libration point orbits near collinear locations are inherently unstable and must be controlled. For Acceleration Reconnection and Turbulence and Electrodynamics of the Moon's Interaction with the Sun (ARTEMIS) Earth-Moon Lissajous orbit operations, stationkeeping is challenging because of short time scales, large orbital eccentricity of the secondary, and solar gravitational and radiation pressure perturbations. ARTEMIS is the first NASA mission continuously controlled at both Earth-Moon L1 and L2 locations and uses a balance of optimization, spacecraft implementation and constraints, and multi-body dynamics. Stationkeeping results are compared to pre-mission research including mode directions.

  18. Lesson "Balance in Nature

    Science.gov (United States)

    Chapanova, V.

    2012-04-01

    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

  19. 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

  20. Social Balance Theory

    OpenAIRE

    Hokky Situngkir; Deni Khanafiah

    2004-01-01

    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...

  1. 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)

    Lissette Ruiz-Tagle

    2011-01-01

    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.

  2. Internal combustion engine cylinder-to-cylinder balancing with balanced air-fuel ratios

    Science.gov (United States)

    Harris, Ralph E.; Bourn, Gary D.; Smalley, Anthony J.

    2006-01-03

    A method of balancing combustion among cylinders of an internal combustion engine. For each cylinder, a normalized peak firing pressure is calculated as the ratio of its peak firing pressure to its combustion pressure. Each cylinder's normalized peak firing pressure is compared to a target value for normalized peak firing pressure. The fuel flow is adjusted to any cylinder whose normalized peak firing pressure is not substantially equal to the target value.

  3. 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

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

    International Nuclear Information System (INIS)

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

  5. Earth\\'s Mass Variability

    OpenAIRE

    Mawad, Ramy

    2014-01-01

    The perturbation of the Earth caused by variability of mass of Earth as additional reason with gravity of celestial bodies and shape of the Earth. The Earth eating and collecting matters from space and loss or eject matters to space through its flying in the space around the Sun. The source of the rising in the global sea level is not closed in global warming and icebergs, but the outer space is the additional important source for this rising. The Earth eats waters from space in unknown mecha...

  6. Melting relations in the iron-sulfur system at ultra-high pressures - Implications for the thermal state of the earth

    Science.gov (United States)

    Williams, Quentin; Jeanloz, Raymond

    1990-01-01

    The melting temperatures of FeS-troilite and of a 10-wt-pct sulfur iron alloy have been measured to pressures of 120 and 90 GPa, respectively. The results document that FeS melts at a temperature of 4100 (+ or - 300) K at the pressure of the core-mantle boundary. Eutecticlike behavior persists in the iron-sulfur system to the highest pressures of measurements, in marked contrast to the solid-solutionlike behavior observed at high pressures in the iron-iron oxide system. Iron with 10-wt-pct sulfur melts at a similar temperature as FeS at core-mantle boundary conditions. If the sole alloying elements of iron within the core are sulfur and oxygen and the outer core is entirely liquid, the minimum temperature at the top of the outer core is 4900 (+ or - 400) K. Calculations of mantle geotherms dictate that there must be a temperature increase of between 1000 and 2000 K across thermal boundary layers within the mantle. If D-double-prime is compositionally stratified, it could accommodate the bulk of this temperature jump.

  7. Bulk Earth carbon and its isotopic value

    Science.gov (United States)

    Jones, A. P.; Mikhail, S.; Basugupta, S.

    2012-12-01

    The carbon isotope distribution in the Earth today is the net product of several primary processes, including planetary accretion, segregation of the core, the Moon-forming giant impact, magma oceans, crustal recycling, and biological processes. Therefore carbon isotope fractionation under mantle pressure and temperature conditions is one of the most important factors in deciphering the messages recorded in mantle samples and will assist towards the greater understanding the geodynamic carbon system. The largest and most powerful geochemical differentiation event during Earth's geologic history was core formation. The behaviour of 13C during this process is little constrained and needs to be investigated to understand the potential effects that it may have had on the carbon isotope composition of the silicate Earth. Isotopic fractionation of carbon at mantle pressure and temperatures in laboratory experiments and for natural terrestrial and extra-terrestrial samples between coexisting elemental carbon and carbides (reducing conditions) are higher than other systems previously investigated and can exceed 12 ‰ in the cores of celestial bodies and observed in Fe-meteorites (Deines and Wickman, 1975; Mikhail et al., 2010). First we review the mean values for carbon in ordinary chondrites and other solar system meteorites (from Mars, Vesta and the Moon) with a value of δ13C ≈ -20 +/- 4 ‰ (Grady et al 2004). Then we review the notion that the bulk Earth δ13C is around -5 ‰ similar to enstatite and carbonaceous chondrites and reflected in the majority of peridotitic mantle materials. Our modelling demonstrates that in order to understand the core/mantle carbon ratio we need to constrain the bulk Earth's initial δ13C value. We can constrain the relative proportion of carbon in the core/mantle by using simple isotopic mass balance and produce a range of carbon contents for the Earth then apply this to the maximum and minimums for the core using geophysical constraints. The mantle dominates the terrestrial carbon reservoir from an initial δ13C value of -5 ‰, but is dwarfed by the core with an initial δ13C value of -20 ‰. REFERENCES: S. Mikhail 2010 AGU U21A-001 abstract; Deines, P., Wickman, F.E., 1975. A contribution to the stable carbon isotope geochemistry of iron meteorites. Geochimica Et Cosmochimica Acta 39, 547-557. Grady, M. Verchovsky A, Wright, I. 2004 Magmatic carbon in Martian meteorites: attempts to constrain the carbon cycle on Mars. Int. J. Astrobiol. 2004;3:117-124.

  8. A hypothesis of earth quake

    CERN Document Server

    Tsai, Yeong-Shyeong

    2008-01-01

    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...

  9. Changes of arterial blood pressure, heart rate, internal body temperature, and blood acido-basic balance in the unanaesthetized rabbit following whole-body gamma irradiation at a mean absorbed dose of 250 rads

    Energy Technology Data Exchange (ETDEWEB)

    Dufour, R.; Court, L.

    1973-09-01

    The general effects of whole-body gamma -irradiation at a mean absorbed dose of 250 rads were studied simultaneously in the unanaesthetized rabbit for 48 hours. They occurred early, with the following characteristics: arterial blood pressure decreased steadily as early as the 2nd hour and reached its minimum value on the 5th hour with a decrease of about 14%; it remained low during the following two days. Heart rate increased during the first hour, was the highest by the end of the second hour, and resumed normal value on the 24th hour. Internal body temperature increased during the 1st hour and was maximum by the end of the 2nd hour, with a mean increase of 1.2 deg C; hyperthermia steadily decreased between the 4th and the 6th hours and had completely disappeared by the 24th hour. Respiratory alkalosis is shown in the acido-basic balance by a raise of pH, a decrease of PCO/sub 2/ and arterial blood bicarbonates. These various changes seem to indicate a double origin, both central and peripheral. (FR)

  10. High-pressure and high-temperature equation of state of cobalt oxide: Implications for redox relations in Earth's mantle

    Energy Technology Data Exchange (ETDEWEB)

    Armentrout, Matthew M.; Rainey, Emma S.G.; Kavner, Abby [UCLA

    2013-07-30

    The high-pressure and high-temperature equation of state of rock salt-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. Fitting a Mie-Grüneisen-Debye model to the data we find best-fit parameters V0 = 77.4 (fixed) Å3, K0 = 190 (1) GPa, K' = 3.49 (4), γ0 = 1.54 (4), q = 2.87 (15), and θ0 = 517.8 K (fixed). We use this newly determined equation of state in conjunction with existing measurements of the thermoelastic parameters of cobalt metal to calculate the Gibbs free-energy difference between the cobalt oxide and cobalt metal phases as a function of pressure and temperature. A comparison of the energetics of the Co/CoO system with the Ni/NiO system predicts that below 58 GPa CoO+Ni is stable relative to NiO+Co, while above 58 GPa the reverse is true. This tipping point in energy can be mapped as a crossing point in the electrochemical potential of the two metal ions, suggesting that cobalt becomes more siderophile than nickel with increasing pressure. This result is in qualitative agreement with existing measurements of nickel and cobalt partition coefficients between mantle and core materials.

  11. The Global Challenge: A Matter of Balance.

    Science.gov (United States)

    Mulford, Bill

    2002-01-01

    Argues that global challenge created by the pressure for change requires educators to understand the balance between continuity and constant change dependence and independence, individualism and community, homogeneity and heterogeneity. To achieve balanced learning and development, education should place greater emphasis on continuity,…

  12. Postural balance in low back pain patients

    DEFF Research Database (Denmark)

    Maribo, Thomas; Stengaard-Pedersen, Kristian; Jensen, Lone Donbk; Andersen, Niels Trolle; Schittz-Christensen, Berit

    2011-01-01

    Low back pain (LBP) patients have poorer postural control compared to healthy controls, and the importance of assessing and addressing balance is a matter of debate. In the clinic, balance is often tested by means of the one leg stand test (OLST) while research often employs center of pressure (Co...

  13. Earth\\'s Mass Variability

    CERN Document Server

    Mawad, Ramy

    2014-01-01

    The perturbation of the Earth caused by variability of mass of Earth as additional reason with gravity of celestial bodies and shape of the Earth. The Earth eating and collecting matters from space and loss or eject matters to space through its flying in the space around the Sun. The source of the rising in the global sea level is not closed in global warming and icebergs, but the outer space is the additional important source for this rising. The Earth eats waters from space in unknown mechanism. The mass of the Earth become greater in November i.e. before transit apoapsis two months, and become latter in February i.e. after transit apoapsis to two months.

  14. Water and sodium balance in space

    DEFF Research Database (Denmark)

    Drummer, C; Norsk, P; Heer, M

    2001-01-01

    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......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...

  15. 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)

    SI Ribas

    2007-10-01

    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.

  16. Mineral solubilities in aqueous fluids at high pressures and temperatures: New thermodynamic model and implications for mass transfer in the Earth's crust and mantle

    Science.gov (United States)

    Dolejš, David; Manning, Craig E.

    2010-05-01

    Aqueous fluids are produced by metamorphic devolatilization and magmatic activity in a variety of settings including continental orogens, subduction zones with magmatic arcs as well as oceanic ridges and sea floor. They are responsible for mobility and transport of inorganic and organic solutes as manifested by alteration or veining, distinct element depletion-enrichment patterns or isotopic disturbances. The impact of many fluid-mediated processes is promoted by high time-integrated fluid fluxes, 101-106 m3 m-2, inferred for diffuse and focused fluid flow through lithosphere. Previous approaches to aqueous speciation have almost exclusively been based on the Helgeson-Kirkham-Flowers equation of state, which, however, suffers from inaccuracies in the vicinity of critical point of water and cannot be extrapolated to very high temperatures and pressures due to the lack of experimental data on dielectric constant of H2O. We propose a new thermodynamic model for dissolution of minerals in aqueous fluids at high temperatures and pressures, which is derived from individual energetic contributions to lattice breakdown, solute hydration and compression of the hydration shell. The thermodynamic properties depend on temperature and H2O density only and are calculated using three to five model parameters calibrated by experimental data. Our formulation of the density dependence has the advantage of behaving as a smooth function at the critical point of H2O, it closely corresponds to the generalized Krichevskii parameter, and it linearly correlates with the Born electrostatic energy. Solubilities of quartz, corundum, rutile, calcite, apatite, fluorite, and portlandite monotonously increase for a given phase by 4-5 orders of magnitude as temperature rises from 200 to 1100 oC along typical geotherms. At constant pressure, however, mineral solubilities initially increase with rising temperature, but subsequently drop. This effect results from a reversal in isobaric expansivity of the aqueous solvent and it is proportional to the charge of solute species. Oxide minerals such as quartz, corundum and rutile dissolve in pure H2O as predominantly neutral species. Consequently, their solubility behavior shows little dependence on solvent properties and their retrograde solubilities are limited to pressures below 1.3 kbar. The Ca-bearing phases (calcite, fluorite, apatite and portlandite), by contrast, dissolve to variably charged species, and the electrostriction effects become more significant. The solubilities of these minerals still decrease at medium and high metamorphic grades and over wide range of pressures. Application of transport theory to our thermodynamic model permits calculation of time-integrated fluid fluxes needed to precipitate mineral veins during metamorphic events. The integrated fluid fluxes along geotherms of 20 and 7 oC km-1 vary from 104 to 1015 m3 m-2. Quartz and calcite require the lowest fluid fluxes, and this is in broad agreement with observations of high mobility and veining of these minerals in many metamorphic environments. Conversely, typical integrated fluid fluxes in crustal shear zones predict transfer of quartz and calcite in quantities of several to tens vol. % whereas the mobility of apatite or rutile lies below 1000 ppm. Although less important for the major element metasomatism, such a transfer may substantially affect trace element budget in metasomatized rocks.

  17. Re-entry dynamics of high area-to-mass ratio objects in eccentric Earth orbits considering drag and solar radiation pressure

    International Nuclear Information System (INIS)

    The discovery of a new population of objects with high area-to-mass ratios (HAMR) in orbits near the geostationary ring has motivated recent research seeking to understand the behaviour of those debris under the influence of certain types of disturbances, such as solar radiation pressure and atmospheric drag. Based on a series of selection criteria, it was made from the NORAD catalogue a list of potential candidates for study. As we developed an orbital propagator that takes into account the major disturbances, it was possible to study the behaviour and variation of orbital parameters during decay of the HAMR objects. The results obtained for two cases studied exhibit the dynamic behaviour of all orbital parameters and show good agreement with the observed decay times

  18. Rare earths

    International Nuclear Information System (INIS)

    For conventional applications, there is limited demand for rare earth elements as well as yttrium and scandium. But the emergence of new high technology applications such as supermagnets, lasers, and superconductors should result in significant demand for some of these elements. This article examines the anticipated applications and demands for rare earth elements over the next decade. It also looks at the implications on the use of available resources. In the context of a growing demand, process methods are reviewed for the recovery of rare earth elements from conventional and unconventional resources. And the article also discusses the challenges facing the mining industry in meeting this opportunity

  19. Balanced Mind Foundation

    Science.gov (United States)

    ... Parent Network: Our Mission Get Started eNews Balanced Mind Updates Jul. 21, 2014 July eUpdate: DBSA Webinars ... Introducing the DBSA Young Adult Council Follow Balanced Mind Parent Network Updates: Balanced Mind Parent Network Updates ...

  20. Balanced Permutation Codes

    OpenAIRE

    Gabrys, Ryan; Milenkovic, Olgica

    2016-01-01

    Motivated by charge balancing constraints for rank modulation schemes, we introduce the notion of balanced permutations and derive the capacity of balanced permutation codes. We also describe simple interleaving methods for permutation code constructions and show that they approach capacity

  1. Earth, atmosphere

    Science.gov (United States)

    Levine, Joel S.

    1991-01-01

    Present understanding of the earth's atmosphere is briefly reviewed. The structure and composition of the atmosphere are described. The origin of the atmosphere and the factors involved in global atmospheric change are addressed.

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

    Directory of Open Access Journals (Sweden)

    D. Yu. Klimushkin

    2004-01-01

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

    Key words. Magnetospheric physics (plasmasphere; MHD waves and instabilities – Space plasma physics (kinetic and MHD theory

  3. High-pressure, temperature elasticity of Fe- and Al-bearing MgSiO3: implications for the Earth's lower mantle

    CERN Document Server

    Zhang, Shuai; Liu, Tao; Stackhouse, Stephen; Militzer, Burkhard

    2015-01-01

    Fe and Al are two of the most important rock-forming elements other than Mg, Si, and O. Their presence in the lower mantle's most abundant minerals, MgSiO_3 bridgmanite, MgSiO_3 post-perovskite and MgO periclase, alters their elastic properties. However, knowledge on the thermoelasticity of Fe- and Al-bearing MgSiO_3 bridgmanite, and post-perovskite is scarce. In this study, we perform ab initio molecular dynamics to calculate the elastic and seismic properties of pure, Fe^{3+}- and Fe^{2+}-, and Al^{3+}-bearing MgSiO_3 perovskite and post-perovskite, over a wide range of pressures, temperatures, and Fe/Al compositions. Our results show that a mineral assemblage resembling pyrolite fits a 1D seismological model well, down to, at least, a few hundred kilometers above the core-mantle boundary, i.e. the top of the D'' region. In D'', a similar composition is still an excellent fit to the average velocities and fairly approximate to the density. We also implement polycrystal plasticity with a geodynamic model to ...

  4. High-pressure, temperature elasticity of Fe- and Al-bearing MgSiO3: Implications for the Earth's lower mantle

    Science.gov (United States)

    Zhang, Shuai; Cottaar, Sanne; Liu, Tao; Stackhouse, Stephen; Militzer, Burkhard

    2016-01-01

    Fe and Al are two of the most important rock-forming elements other than Mg, Si, and O. Their presence in the lower mantle's most abundant minerals, MgSiO3 bridgmanite, MgSiO3 post-perovskite and MgO periclase, alters their elastic properties. However, knowledge on the thermoelasticity of Fe- and Al-bearing MgSiO3 bridgmanite, and post-perovskite is scarce. In this study, we perform ab initio molecular dynamics to calculate the elastic and seismic properties of pure, Fe3+- and Fe2+-, and Al3+-bearing MgSiO3 perovskite and post-perovskite, over a wide range of pressures, temperatures, and Fe/Al compositions. Our results show that a mineral assemblage resembling pyrolite fits a 1D seismological model well, down to, at least, a few hundred kilometers above the core-mantle boundary, i.e. the top of the D? region. In D?, a similar composition is still an excellent fit to the average velocities and fairly approximate to the density. We also implement polycrystal plasticity with a geodynamic model to predict resulting seismic anisotropy, and find post-perovskite with predominant (001) slip across all compositions agrees best with seismic observations in the D?.

  5. 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)

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

    2012-12-01

    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.

  6. Greenland ice sheet mass balance: a review

    DEFF Research Database (Denmark)

    Khan, Shfaqat Abbas; Aschwanden, Andy; Bjrk, Anders A.; Wahr, John; Kjeldsen, Kristian K.; Kjr, Kurt H.

    2015-01-01

    Over the past quarter of a century the Arctic has warmed more than any other region on Earth, causing a profound impact on the Greenland ice sheet (GrIS) and its contribution to the rise in global sea level. The loss of ice can be partitioned into processes related to surface mass balance and to ...

  7. An Analog Earth Climate Model

    Science.gov (United States)

    Varekamp, J. C.

    2010-12-01

    The earth climate is broadly governed by the radiative power of the sun as well as the heat retention and convective cooling of the atmosphere. I have constructed an analog earth model for an undergraduate climate class that simulates mean climate using these three parameters. The ‘earth’ is a hollow, black, bronze sphere (4 cm diameter) mounted on a thin insulated rod, and illuminated by two opposite optic fibers, with light focused on the sphere by a set of lenses. The sphere is encased in a large double-walled aluminum cylinder (34 cm diameter by 26 cm high) with separate water cooling jackets at the top, bottom, and sides. The cylinder can be filled with a gas of choice at a variety of pressures or can be run in vacuum. The exterior is cladded with insulation, and the temperature of the sphere, atmosphere and walls is monitored with thermocouples. The temperature and waterflow of the three cooling jackets can be monitored to establish the energy output of the whole system; the energy input is the energy yield of the two optic fibers. A small IR transmissive lens at the top provides the opportunity to hook up the fiber of a hyper spectrometer to monitor the emission spectrum of the black ‘earth’ sphere. A pressure gauge and gas inlet-outlet system for flushing of the cell completes it. The heat yield of the cooling water at the top is the sum of the radiative and convective components, whereas the bottom jacket only carries off the radiative heat of the sphere. Undergraduate E&ES students at Wesleyan University have run experiments with dry air, pure CO2, N2 and Ar at 1 atmosphere, and a low vacuum run was accomplished to calibrate the energy input. For each experiment, the lights are flipped on, the temperature acquisition routine is activated, and the sphere starts to warm up until an equilibrium temperature has been reached. The lights are then flipped off and the cooling sequence towards ambient is registered. The energy input is constant for a given experiment. For each time increment the radiative heat loss of the sphere is calculated from the Stefan Boltzman expression using the observed temperature at that time. The heating of the ‘earth sphere’ is accounted for in the energy balance equation by applying the temperature increase per time increment with the specific heat of bronze. The remaining energy term is the sum of the convective cooling and greenhouse effect. The heat budgets of the cooling trajectories were calculated analogous, with radiative and convective cooling causing the temperature drop per time increment. The greenhouse component again is lumped with the convective term. Equilibrium temperatures of 50-70 C were reached, with ambient temperature at 22 C. Somewhat surprising, experiments with radiatively neutral pure Argon gas yielded the highest equilibrium temperatures. Argon had the lowest specific heat of the gases used, and the observed equilibrium temperatures for different cell gases broadly scaled inversely with the heat capacity of those gases. Apparently, the efficiency of the free convective cooling strongly impacts the equilibrium temperatures. The greenhouse effects possibly have only a minor impact on final temperature as a result of the short cell pathlength. Experiments at higher cell filling pressures may provide more insight in this.

  8. THE COSMIC-RAY INTENSITY NEAR THE ARCHEAN EARTH

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.

  9. Tracking Earths global energy (Invited)

    Science.gov (United States)

    Trenberth, K. E.

    2009-12-01

    With global mean temperatures in 2008 the lowest since 2000, but carbon dioxide increasing apace, where has global warming gone? We use available observations to estimate contributions to changes in the Earths radiation imbalance from changes in ocean heat content, sea level, sea ice, land ice, land heat, and atmospheric temperatures. Sea level rise slowed somewhat with the double La Nia in 2007-2008-2009 but not as much as the rise in ocean content appears to have, and the difference seems to be made up from increased melting of land ice (Greenland and Antarctica). However, such a change in the main contributions to sea level rise does not satisfy the energy budget, as a gain factor of about 50 is achieved by putting energy into melting land ice vs ocean expansion. Changes in the sun have contributed at the 12% level. CERES observations suggest an increase in absorbed energy, the opposite of what is required to balance the energy budget. If we can not understand what is happening in recent times, what business have we in considering geoengineering?

  10. Improve Your Balance

    Science.gov (United States)

    ... My Go4Life Get Free Stuff Be a Partner Balance Improve Your Balance Each year, more than 2 million older Americans ... types of exercise — endurance , strength , balance, and flexibility . Balance Stand on One Foot Heel-to-Toe Walk ...

  11. Balance in Assessment

    Science.gov (United States)

    White, Richard

    2007-01-01

    The review by Black and Wiliam of national systems makes clear the complexity of assessment, and identifies important issues. One of these is "balance": balance between local and central responsibilities, balance between the weights given to various purposes of schooling, balance between weights for various functions of assessment, and balance…

  12. Digital Earth - A sustainable Earth

    Science.gov (United States)

    Mahavir

    2014-02-01

    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.

  13. A reconciled estimate of ice-sheet mass balance

    DEFF Research Database (Denmark)

    Shepherd, Andrew; Ivins, Erik R; A, Geruo; Barletta, Valentina Roberta; 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; Velicogna, Isabella; Wahr, John; Whitehouse, Pippa L; Wingham, Duncan J; Yi, Donghui; Young, Duncan; Zwally, H Jay

    2012-01-01

    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...

  14. A reconciled estimate of ice-sheet mass balance

    DEFF Research Database (Denmark)

    Shepherd, Andrew; Ivins, Erik R; A, Geruo; Barletta, Valentina Roberta; 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; Velicogna, Isabella; Wahr, John; Whitehouse, Pippa L; Wingham, Duncan J; Yi, Donghui; Young, Duncan; Zwally, H Jay

    2012-01-01

    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 agre...

  15. Rare earths

    Science.gov (United States)

    Gambogi, J.

    2013-01-01

    Global mine production of rare earths was estimated to have declined slightly in 2012 relative to 2011 (Fig. 1). Production in China was estimated to have decreased to 95 from 105 kt (104,700 from 115,700 st) in 2011, while new mine production in the United States and Australia increased.

  16. Social Balance Theory

    CERN Document Server

    Khanafiah, D; Khanafiah, Deni; Situngkir, Hokky

    2004-01-01

    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.

  17. 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.

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

    International Nuclear Information System (INIS)

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

  19. Determining Atmospheric Pressure Using a Water Barometer

    Science.gov (United States)

    Lohrengel, C. Frederick, II; Larson, Paul R.

    2012-01-01

    The atmosphere is an envelope of compressible gases that surrounds Earth. Because of its compressibility and nonuniform heating by the Sun, it is in constant motion. The atmosphere exerts pressure on Earth's surface, but that pressure is in constant flux. This experiment allows students to directly measure atmospheric pressure by measuring the…

  20. Hydrogen Escape from early Earth and Mars

    Science.gov (United States)

    Zugger, M. E.; Ramirez, R. M.; Kasting, J. F.

    2012-12-01

    A controversy regarding hydrodynamic escape rates arose when Tian et al. (2005) published transonic escape rates for an atmosphere composed of pure H2. Tian et al. concluded that the hydrogen escape rate from early Earth would have been a factor of 20 or more slower than the diffusion limit, even if the solar EUV (extreme ultraviolet) flux was enhanced by a factor of 5 relative to today. This conclusion was challenged by Catling (2006), who pointed out that solar EUV fluxes could have been much higher than this so that plenty of energy should have been available to power escape. This controversy has remained unresolved to date. Hydrogen escape from early Mars is also of interest. As discussed in this session in a complementary paper by Ramirez et al., collision-induced absorption by molecular hydrogen could have helped to warm early Mars, perhaps explaining the formation of valleys and valley networks. Ramirez et al. have shown that a mixture of 90% CO2 and 10% H2 is capable raising early Mars' surface temperature above the freezing point of water, for surface pressures exceeding ~3 bar. However, we need to understand whether H2 mixing ratios of 10% are physically plausible. The H2 partial pressure in Mars' early atmosphere would have been determined by the balance between volcanic outgassing and escape to space. The 10% mixing ratio is high compared to the value of ~10-3 typically assumed for early Earth. But Mars' early atmosphere may have been more reduced than Earth's (Wadwha, 2001); if the hydrogen escape rate on Mars was also slower than on Earth, then additional increases in atmospheric hydrogen concentration are possible. To answer these questions about the early atmospheres of Earth and Mars, we have modified an existing model of hydrodynamic escape, developed by F. Tian, J. Kasting, and others, to converge for atmospheres with a wide range of hydrogen mixing ratios. The model finds subsonic solutions to the hydrodynamic equations; these can be shown to have nearly the same escape flux as the transonic solution (the fastest outflow possible), provided that the maximum Mach number of the flow is close to unity. We achieve high Mach numbers by varying the velocity uinfinity, at the top of the model. By doing so, we simulate nonthermal, as well as thermal, escape processes. We assert without proof that there is a limit beyond which one cannot further increase uinfinity without producing unphysical results; that limit is the maximum, EUV-limited hydrodynamic escape rate. At low hydrogen mixing ratios, the escape rate follows the diffusion limit, as expected. At higher hydrogen mixing ratios, though, the escape rate flattens out, and even decreases. A similar effect is found when we apply our model to early Mars. Thus, there may have been an optimum time in Mars' early history for building up a dense, warm CO2-H2 atmosphere, after the solar EUV flux had dropped somewhat, but while the volcanic outgassing rate and magnetic field were still strong. If so, this CO2-H2 greenhouse mechanism may help to explain how the valleys formed on early Mars. References Catling DC. 2006. Comment on "A hydrogen-rich early Earth atmosphere". Science 311: 38a-b Tian F, Toon OB, Pavlov AA, De Sterck H. 2005. A hydrogen rich early Earth atmosphere. Science 308: 1014-7 Wadhwa M. 2001. Redox state of Mars' upper mantle and crust from Eu anomalies in Shergottite pyroxenes. Science 291: 1527-30

  1. Skylab water balance analysis

    Science.gov (United States)

    Leonard, J. I.

    1977-01-01

    The water balance of the Skylab crew was analyzed. Evaporative water loss using a whole body input/output balance equation, water, body tissue, and energy balance was analyzed. The approach utilizes the results of several major Skylab medical experiments. Subsystems were designed for the use of the software necessary for the analysis. A partitional water balance that graphically depicts the changes due to water intake is presented. The energy balance analysis determines the net available energy to the individual crewman during any period. The balances produce a visual description of the total change of a particular body component during the course of the mission. The information is salvaged from metabolic balance data if certain techniques are used to reduce errors inherent in the balance method.

  2. ISLSCP II Earth Radiation Budget Experiment (ERBE) Monthly Albedo, 1986-1990

    Data.gov (United States)

    National Aeronautics and Space Administration The goals of the Earth Radiation Budget Experiment (ERBE) are (1) to understand the radiation balance between the Sun, Earth, atmosphere, and space and (2) to...

  3. ISLSCP II Earth Radiation Budget Experiment (ERBE) Monthly Albedo, 1986-1990

    Data.gov (United States)

    National Aeronautics and Space Administration — The goals of the Earth Radiation Budget Experiment (ERBE) are (1) to understand the radiation balance between the Sun, Earth, atmosphere, and space and (2) to...

  4. ISLSCP II Earth Radiation Budget Experiment (ERBE) Monthly Albedo, 1986-1990

    Data.gov (United States)

    National Aeronautics and Space Administration ABSTRACT: The goals of the Earth Radiation Budget Experiment (ERBE) are (1) to understand the radiation balance between the Sun, Earth, atmosphere, and space and...

  5. Polarization-balanced beamsplitter

    International Nuclear Information System (INIS)

    A beamsplitter assembly is disclosed that includes several beamsplitter cubes arranged to define a plurality of polarization-balanced light paths. Each polarization-balanced light path contains one or more balanced pairs of light paths, where each balanced pair of light paths includes either two transmission light paths with orthogonal polarization effects or two reflection light paths with orthogonal polarization effects. The orthogonal pairing of said transmission and reflection light paths cancels polarization effects otherwise caused by beamsplitting. 10 figs

  6. Coaching for Balance.

    Science.gov (United States)

    Larson, Bonnie

    2001-01-01

    Discusses coaching for balance the integration of the whole self: physical (body), intellectual (mind), spiritual (soul), and emotional (heart). Offers four ways to identify problems and tell whether someone is out of balance and four coaching techniques for creating balance. (Contains 11 references.) (JOW)

  7. 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.)

  8. Objective assessment of postural balance through use of the variable resistance balance board.

    Science.gov (United States)

    Mechling, R W

    1986-05-01

    The purpose of this study was to evaluate postural balance with a practical clinical assessment tool. I evaluated eight men and eight women in their 20s, using a variable resistance balance board, to determine the deviation of their average center of pressure in the anterior-posterior plane during stance. The resulting data were compared with the average center of pressure deviation of eight men in their 20s as measured by Murray et al with a force platform. The difference between the two men's groups was not statistically significant (p less than .05). These findings suggest that physical therapists may determine average center of pressure data and may assign progressive balance tasks that match any patient's level of center of pressure control. PMID:3703933

  9. Space vehicle with artificial gravity and earth-like environment

    Science.gov (United States)

    Gray, V. H. (Inventor)

    1973-01-01

    A space vehicle adapted to provide an artificial gravity and earthlike atmospheric environment for occupants is disclosed. The vehicle comprises a cylindrically shaped, hollow pressure-tight body, one end of which is tapered from the largest diameter of the body, the other end is flat and transparent to sunlight. The vehicle is provided with thrust means which rotates the body about its longitudinal axis, generating an artificial gravity effect upon the interior walls of the body due to centrifugal forces. The walls of the tapered end of the body are maintained at a temperature below the dew point of water vapor in the body and lower than the temperature near the transparent end of the body. The controlled environment and sunlight permits an earth like environment to be maintained wherein the CO2/O2 is balanced, and food for the travelers is supplied through a natural system of plant life grown on spacecraft walls where soil is located.

  10. 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

  11. The Genesis of the Earth's Moon

    OpenAIRE

    De Aquino, Fran

    2015-01-01

    Here we show how in the early Earth, a matter column, which extended from the Earth's surface down to near the upper boundary of the outer core, it was vaporized due to a suddenly increase of temperature greater than 8,367°C, and after ejected of the Earth by the enormous pressure at the bottom of the mantle (~136 GPa), forming posteriorly the Moon.

  12. Functional balance tests

    Directory of Open Access Journals (Sweden)

    Parvin Raji

    2012-12-01

    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.

  13. Medical Devices Assess, Treat Balance Disorders

    Science.gov (United States)

    2009-01-01

    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.

  14. The EarthCARE Power System

    Science.gov (United States)

    Ruf, Daniel; Beaufils, Gilles

    2011-10-01

    This paper describes the Electrical Power System of the EarthCARE satellite. EarthCARE is an Earth-observation mission aiming to improve the understanding of the Earth's radiation balance. It will fly in a specifically low polar Earth orbit with an altitude of around 400 km. The satellite with an orbit average power demand of about 1700 W is supplied by an unregulated 28 V power bus. Electrical power is generated by a deployable, rotating solar array with an active area of 21.5 m2. Energy is stored by a Li-Ion battery with a capacity of 326 Ah. The central Power Conditioning and Control Unit controls the solar array power by maximum power point tracking. It distributes protected power supply lines to the electrical units, heaters and release initiators.

  15. A safety analysis of warhead balancing

    Energy Technology Data Exchange (ETDEWEB)

    Bott, T.F.

    1998-12-01

    Reentry vehicles (RVs) carrying warheads from ballistic missiles must be carefully balanced with the warhead in situ to prevent wobble as the RVs enter the earth`s atmosphere to prevent inaccuracy or loss of the warhead. This balancing is performed on a dynamic balancing machine that rotates the RV at significant angular velocities. Seizure of the spindle shaft of the machine could result in rapid deceleration of the rotating assembly, which could over-stress and shear bolts or other structures that attach the RV to the balancing machine. This could result in undesired motions of the RV and impact of the RV on equipment or structures in the work area. This potential safety problem has long been recognized in a general way, but no systematic investigation of the possible accident sequences had been performed. The purpose of this paper is to describe an integrated set of systems analysis techniques that worked well in developing a set of accident sequences that describe the motions of the RV following a spindle-shaft seizure event.

  16. Identifying Balance in a Balanced Scorecard System

    Science.gov (United States)

    Aravamudhan, Suhanya; Kamalanabhan, T. J.

    2007-01-01

    In recent years, strategic management concepts seem to be gaining greater attention from the academicians and the practitioner's alike. Balanced Scorecard (BSC) concept is one such management concepts that has spread in worldwide business and consulting communities. The BSC translates mission and vision statements into a comprehensive set of

  17. Earth Observation Plan Focuses on User Needs and Measurements

    Science.gov (United States)

    Showstack, Randy

    2014-09-01

    The White House's new U.S. National Plan for Civil Earth Observations focuses on user needs and measurements while defining a framework for constructing a balanced portfolio of Earth observations and observing systems, officials with the White House Office of Science and Technology Policy (OSTP) said at a 4 September forum about the plan.

  18. Chemical Equation Balancing.

    Science.gov (United States)

    Blakley, G. R.

    1982-01-01

    Reviews mathematical techniques for solving systems of homogeneous linear equations and demonstrates that the algebraic method of balancing chemical equations is a matter of solving a system of homogeneous linear equations. FORTRAN programs using this matrix method to chemical equation balancing are available from the author. (JN)

  19. Conclusion: The balanced company

    DEFF Research Database (Denmark)

    Scheuer, John Damm; Jensen, Inger

    This concluding chapter brings together the various research findings of the book "The balanced company - organizing for the 21st Century" and develops a general overview of their implications for our understanding of the balancing processes unfolding in companies and organizations....

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

    International Nuclear Information System (INIS)

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

  1. Diasporic Trauma in Unaccustomed Earth

    Directory of Open Access Journals (Sweden)

    Ling YUN

    2014-04-01

    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.

  2. Load Balancing Scientific Applications

    Energy Technology Data Exchange (ETDEWEB)

    Pearce, Olga Tkachyshyn [Texas A & M Univ., College Station, TX (United States)

    2014-12-01

    The largest supercomputers have millions of independent processors, and concurrency levels are rapidly increasing. For ideal efficiency, developers of the simulations that run on these machines must ensure that computational work is evenly balanced among processors. Assigning work evenly is challenging because many large modern parallel codes simulate behavior of physical systems that evolve over time, and their workloads change over time. Furthermore, the cost of imbalanced load increases with scale because most large-scale scientific simulations today use a Single Program Multiple Data (SPMD) parallel programming model, and an increasing number of processors will wait for the slowest one at the synchronization points. To address load imbalance, many large-scale parallel applications use dynamic load balance algorithms to redistribute work evenly. The research objective of this dissertation is to develop methods to decide when and how to load balance the application, and to balance it effectively and affordably. We measure and evaluate the computational load of the application, and develop strategies to decide when and how to correct the imbalance. Depending on the simulation, a fast, local load balance algorithm may be suitable, or a more sophisticated and expensive algorithm may be required. We developed a model for comparison of load balance algorithms for a specific state of the simulation that enables the selection of a balancing algorithm that will minimize overall runtime.

  3. Free oscillation of the Earth

    Directory of Open Access Journals (Sweden)

    Y. Abedini

    2000-06-01

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

  4. Thermodynamics of the Earth

    International Nuclear Information System (INIS)

    Applications of elementary thermodynamic principles to the dynamics of the Earth lead to robust, quantitative conclusions about the tectonic effects that arise from convection. The grand pattern of motion conveys deep heat to the surface, generating mechanical energy with a thermodynamic efficiency corresponding to that of a Carnot engine operating over the adiabatic temperature gradient between the heat source and sink. Referred to the total heat flux derived from the Earth's silicate mantle, the efficiency is 24% and the power generated, 7.7 x 1012 W, causes all the material deformation apparent as plate tectonics and the consequent geological processes. About 3.5% of this is released in seismic zones but little more than 0.2% as seismic waves. Even major earthquakes are only localized hiccups in this motion. Complications that arise from mineral phase transitions can be used to illuminate details of the motion. There are two superimposed patterns of convection, plate subduction and deep mantle plumes, driven by sources of buoyancy, negative and positive respectively, at the top and bottom of the mantle. The patterns of motion are controlled by the viscosity contrasts (>104 : 1) at these boundaries and are self-selected as the least dissipative mechanisms of heat transfer for convection in a body with very strong viscosity variation. Both are subjects of the thermodynamic efficiency argument. Convection also drives the motion in the fluid outer core that generates the geomagnetic field, although in that case there is an important energy contribution by compositional separation, as light solute is rejected by the solidifying inner core and mixed into the outer core, a process referred to as compositional convection. Uncertainty persists over the core energy balance because thermal conduction is a drain on core energy that has been a subject of diverse estimates, with attendant debate over the need for radiogenic heat in the core. The geophysical approach to thermal physics, especially thermal expansion and the Grueneisen parameter, invokes insights that have disappeared from view in 'mainstream' physics.

  5. Errors in potassium balance

    International Nuclear Information System (INIS)

    Six overweight adult subjects given a low calorie diet containing adequate amounts of nitrogen but subnormal amounts of potassium (K) were observed on the Clinical Research Center for periods of 29 to 40 days. Metabolic balance of potassium was measured together with frequent assays of total body K by 40K counting. Metabolic K balance underestimated body K losses by 11 to 87% (average 43%): the intersubject variability is such as to preclude the use of a single correction value for unmeasured losses in K balance studies

  6. Rotating Balances Used for Fluid Pump Testing

    Science.gov (United States)

    Skelley, Stephen; Mulder, Andrew

    2014-01-01

    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.

  7. Global analysis of river systems: from Earth system controls to Anthropocene syndromes.

    Science.gov (United States)

    Meybeck, Michel

    2003-12-29

    Continental aquatic systems from rivers to the coastal zone are considered within two perspectives: (i) as a major link between the atmosphere, pedosphere, biosphere and oceans within the Earth system with its Holocene dynamics, and (ii) as water and aquatic biota resources progressively used and transformed by humans. Human pressures have now reached a state where the continental aquatic systems can no longer be considered as being controlled by only Earth system processes, thus defining a new era, the Anthropocene. Riverine changes, now observed at the global scale, are described through a first set of syndromes (flood regulation, fragmentation, sediment imbalance, neo-arheism, salinization, chemical contamination, acidification, eutrophication and microbial contamination) with their related causes and symptoms. These syndromes have direct influences on water uses, either positive or negative. They also modify some Earth system key functions such as sediment, water, nutrient and carbon balances, greenhouse gas emissions and aquatic biodiversity. Evolution of river syndromes over the past 2000 years is complex: it depends upon the stages of regional human development and on natural conditions, as illustrated here for the chemical contamination syndrome. River damming, eutrophication and generalized decrease of river flow due to irrigation are some of the other global features of river changes. Future management of river systems should also consider these long-term impacts on the Earth system. PMID:14728790

  8. Pressure vessel for a nuclear power station

    International Nuclear Information System (INIS)

    This proposal concerns the temperature balance inside a pressure vessel of reinforced concrete which is provided with a certain number of caverns covered with a metallic layer. In the center is a gas cooled high temperature nuclear reactor. Inside the pressure vessel there is a closed loop system where a cooling medium transports heat from places with high temperature to places with lower temperature. This ensures the temperature balance for avoiding thermal stresses in the pressure vessel walls. (UWI)

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

    International Nuclear Information System (INIS)

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

  10. Cloud radiation interaction and the Earth's climate: Relevance to the climate of the Arctic

    International Nuclear Information System (INIS)

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

  11. Balance Disorders (For Parents)

    Science.gov (United States)

    ... the rear are semicircular canals, which affect balance. Connecting them is the vestibule (with sensory organs known ... of the eye) have light-sensitive cells called rods and cones. When we look at something, light ...

  12. National Energy Balance-1987

    International Nuclear Information System (INIS)

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

  13. The Balanced Literacy Diet.

    Science.gov (United States)

    Willows, Dale

    2002-01-01

    Describes professional development program in Ontario school district to improve student reading and writing skills. Program used food-pyramid concepts to help teacher learn to provide a balanced and flexible approach to literacy instruction based on student needs. (PKP)

  14. Energy balances 2000

    International Nuclear Information System (INIS)

    The energy balances of the Danish Statistical Office are the designation of the goods balances, which are tabulated for each energy article in both physical entities (quantities) and in base rates (values). The balance concept is connected to the definition supply = use, which is the basis for the construction of the system. The supply is determined as the sum of two items: import and production while the total use is the sum of 138 items: export, waste and transmission loss, stock increase, input in lack of the 130 industries, and private consumption divided into 5 consumption groups. The statistical analysis is performed yearly in both quantities and values for 35 energy articles. Values are computed for base rates, profits, taxes, VAT and market prices (buyer's price), respectively. The energy balances from 1975 to 2000 are presented for comparison. (EHS)

  15. The Balanced Company

    DEFF Research Database (Denmark)

    in consumers' and other stakeholder's eyes. Leaders also have to acknowledge that there are times when organizations have to be taken out of balance, since it is necessary to 'unfreeze' existing relationships in organizations during change. Therefore, there are decision and organizing processes......Controlling the sustainability of production processes and ethical employment of the work force in suppliers' production facilities far away from the home country has resulted in new challenges for managers. They now have to consider how important it is for customers, investors and employees to see...... changes in their environments. Communication specialists need to make balanced decisions which take the different value systems and assumptions of stakeholders into consideration. Change specialists need to balance the need for continuity and change. Managers need to make balanced decisions about whether...

  16. 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.)

  17. 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.)

  18. Bruhat and balanced graphs

    OpenAIRE

    Ehrenborg, Richard; Readdy, Margaret A.

    2013-01-01

    We generalize chain enumeration in graded partially ordered sets by relaxing the graded, poset and Eulerian requirements. The resulting balanced digraphs, which include the classical Eulerian posets having an R-labeling, implies the existence of the (non-homogeneous) cd-index, a key invariant for studying inequalities for the flag vector of polytopes. Mirroring Alexander duality for Eulerian posets, we show an analogue of Alexander duality for balanced digraphs. For Bruhat graphs of Coxeter g...

  19. Energy Balance and Obesity

    OpenAIRE

    Hill, James O; Wyatt, Holly R; Peters, John C.

    2012-01-01

    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...

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

    Science.gov (United States)

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

    2014-04-01

    [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

  1. Exercise to Improve Your Balance

    Science.gov (United States)

    ... nia.nih.gov/Go4Life Exercise to Improve Your Balance Having good balance is important for many everyday activities, such as ... fracture of the arm, hand, ankle, or hip. Balance exercises can help you prevent falls and avoid ...

  2. Balances instruments, manufacturers, history

    CERN Document Server

    Robens, Erich; Kiefer, Susanne

    2014-01-01

    The book deals mainly with direct mass determination by means of a conventional balances. It covers the history of the balance from the beginnings in Egypt earlier than 3000 BC to recent developments. All balance types are described with emphasis on scientific balances. Methods of indirect mass determination, which are applied to very light objects like molecules and the basic particles of matter and celestial bodies, are included.  As additional guidance, today’s manufacturers are listed and the profile of important companies is reviewed. Several hundred photographs, reproductions and drawings show instruments and their uses. This book includes commercial weighing instruments for merchandise and raw materials in workshops as well as symbolic weighing in the ancient Egyptian’s ceremony of ‘Weighing of the Heart’, the Greek fate balance, the Roman  Justitia, Juno Moneta and Middle Ages scenes of the Last Judgement with Jesus or St. Michael and of modern balances. The photographs are selected from the...

  3. Development of the NTF-117S Semi-Span Balance

    Science.gov (United States)

    Lynn, Keith C.

    2010-01-01

    A new high-capacity semi-span force and moment balance has recently been developed for use at the National Transonic Facility at the NASA Langley Research Center. This new semi-span balance provides the NTF a new measurement capability that will support testing of semi-span test models at transonic high-lift testing regimes. Future testing utilizing this new balance capability will include active circulation control and propulsion simulation testing of semi-span transonic wing models. The NTF has recently implemented a new highpressure air delivery station that will provide both high and low mass flow pressure lines that are routed out to the semi-span models via a set high/low pressure bellows that are indirectly linked to the metric end of the NTF-117S balance. A new check-load stand is currently being developed to provide the NTF with an in-house capability that will allow for performing check-loads on the NTF-117S balance in order to determine the pressure tare affects on the overall performance of the balance. An experimental design is being developed that will allow for experimentally assessing the static pressure tare affects on the balance performance.

  4. Watt and joule balances

    Science.gov (United States)

    Robinson, Ian A.

    2014-04-01

    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 and his co-authors at NRC describes how they have made this essential measurement. The accuracy of the watt balance may also depend on the alignment of the apparatus. Two papers deal with this important issue. The first, by Sanchez and his co-authors at NRC, shows that their balance is insensitive to a range of alignments and concentrates on the essential alignments that contribute directly to the overall uncertainty of the apparatus. Thomas and his co-authors at LNE describe their technique for reducing uncertainties in their watt balance by aligning its coil in the field of the magnet to minimize both horizontal forces and torques about horizontal axes. The search for discrepancies between the results from watt balances has encouraged researchers to consider possible error mechanisms arising from the secondary electrical interactions between the coil of a watt balance and other parts of the apparatus. Researchers from INRIM have two such papers: one considering magnetic interactions and the other considering electrostatic interactions. It is essential that such investigations are carried out: both to prove that the problems are understood and for the guidance of those building the next generation of watt and joule balances. The next four papers describe aspects of the construction of watt balances. The BIPM watt balance group describe the principles behind their simultaneous measurement scheme for a watt balance. The balance that they are constructing can also be used in the conventional two-phase mode and their paper describes the relative advantages and disadvantages of the two modes of operation. In a watt balance there are some advantages to precise vertical movement of the coil. The METAS group describe the two mechanisms that they have tested to achieve such motion and give the reasons for the choice of mechanism for use in the balance that they are constructing. The KRISS watt balance group are in the initial phases of the design and construction of a watt balance and their paper provides valuable information on the design that they are building. The design of the main magnet of a watt balance is critical to its successful operation, and an important assumption of watt balance operation is that the field of the magnet in moving mode is equivalent to that in weighing mode. Sutton and Clarkson from MSL describe a novel magnet which is designed to address this issue. The international prototype of the kilogram is kept in air but, after redefinition, the best realizations of the mass unit will be in vacuum. In their paper Berry and Davidson from NPL describe progress in techniques which relate mass measured in vacuum to that measured in air. Such techniques will be essential for making the results of watt and joule balance measurements available to science and industry. Both the NIST and NPL Mark II (NRC) watt balances use knife edges to act as the pivots for the beam. Knife edges suffer from hysteresis which can produce systematic offsets during weighing. In their paper Choi (KRISS) and Robinson (NPL) describe the analysis of this problem using both finite element (FEM) techniques and a stand-alone balance designed for testing knife edges. The last two papers deal with the possible future of the watt balance technique. The BIPM simultaneous measurement scheme for the watt balance was originally conceived for operation at cryogenic temperatures with a superconducting coil. In their paper de Mirandes and her co-authors describe initial work on the principles of this superconducting variant of the BIPM watt balance and concentrate on the characteristics of the superconducting coil in comparison with those of a normal coil. The final paper is a good example of serendipity in which Kibble (Independent Consultant) was designing novel watt balances based on seismometer suspensions and Robinson (NPL) had derived a set of general expressions, which are required for a watt balance to be immune to a range of common misalignments but also lead to the design of watt balances with a range of coil motions. The combination of these techniques has led to the novel watt balance designs which are described. Finally I would like to thank: the editor of Metrologia and the editorial staff of IOP Publishing, the referees who have responded rapidly to requests and have kept the issue on schedule, and the authors who have taken the time to provide a range of papers showing the breadth of the work required to build and operate watt or joule balances. References [1] Andreas B et al 2011 Determination of the Avogadro constant by counting the atoms in a 28Si crystal Phys. Rev. Lett. 106 030801 [2] BIPM 2013 Report of the 14th Meeting of the CCM Sèvres pp 34-7 [3] Steiner R 2013 History and progress on accurate measurements of the Planck constant Rep. Prog. Phys. 76 016101 [4] Stock M 2013 Watt balance experiments for the determination of the Planck constant and the redefinition of the kilogram Metrologia 50 R1-16 [5] Li S, Han B, Li Z and Lan J 2012 Precisely measuring the Planck constant by electromechanical balances Measurement 45 1-13 [6] Eichenberger A, Genevès G and Gournay P 2009 Determination of the Planck constant by means of a watt balance Eur. Phys. J. Spec. Top. 172 363-83 [7] Robinson I A 2009 Toward the redefinition of the kilogram: measurements of Planck's constant using watt balances IEEE Trans. Instrum. Meas. 58 942-8

  5. Systems' optimization: Achieving the balance

    Science.gov (United States)

    Kraus, Peter

    1994-04-01

    Fuel cells for stationary power generation applications are being pursued on a large scale worldwide in an effort to achieve commercialization before the turn of the century. Some aspects of system optimization are discussed illustrating the influence of basic system design possibilities. Design variants investigated include alternatives for anode and cathode gas supply and gas recycling, methods to achieve self-sufficiency on water for the reforming of natural gas, and recovery of unspent fuel from the anode exhaust. Especially in small systems for decentralized applications, e.g., industrial cogeneration, system simplification is decisive to bring down the capital cost of the balance-of-plant. Trade-offs between system complexity and efficiency are possible to optimize the economy. In large plants, high-temperature fuel cell can be supplemented with bottoming cycles for best fuel utilization. Gas turbines and steam turbines can be evaluated, having strong influence on the system design pressures and, therefore, system cost.

  6. Near Earth Objects

    DEFF Research Database (Denmark)

    Wolff, Stefan

    2006-01-01

    , Near Earth Objects: Asteroids and comets following paths that bring them near the Earth. NEOs have collided with the Earth since its formation, some causing local devastation, some causing global climate changes, yet the threat from a collision with a near Earth object has only recently been recognised...

  7. Balanced Integrated Regulatory Oversight

    International Nuclear Information System (INIS)

    Reactor safety, protecting the public health and safety, and protecting the environment must always be the nuclear regulator's top priorities. Enabling the use of nuclear power for the benefit of society, while protecting the public and the environment requires the regulator to balance many factors. In addition, the regulator is only one part of the overall government that must consider many factors as it carries out its societal responsibilities. Some of the factors that must be balanced and the practical impacts on how the regulator carries out its responsibilities will be addressed. The first International Conference on Effective Regulatory Systems, held in Moscow, Russian Federation, in 2006, focused on safety and security challenges with a goal of improving regulatory effectiveness through cooperation and sharing of information and best practices. The challenge of meeting both safety and security objectives is one example of potentially competing programmes that must be balanced. Other balances that must be evaluated include the benefits of safety improvements compared to the cost of implementation, the use of deterministic and probabilistic approaches, communication openness balanced with the protection of information that could be used for detrimental purposes, and timeliness of regulatory decision making balanced with the need to perform quality work in support of oversight responsibilities. A balanced and integrated approach to regulatory oversight is vital to ensuring that the regulatory body remains effective in its mission to enable the use of nuclear power while protecting the public and the environment. This concept is applicable to nations beginning a nuclear programme as well as established and experienced regulatory bodies. (author)

  8. Research of Human Postural Balance Parameters

    Directory of Open Access Journals (Sweden)

    Julius Griškevičius

    2011-02-01

    Full Text Available In present article postural balance between subjects with stroke and healthy subjects, is being investigated with eyes opened and eyes closed. In the research participated 30 healthy subjects and 15 subjects with stroke. At the same time two experimental measurements were performed – postural balance was measured using balance platform and oscillations of the centre of mass were observed using two-axial accelerometer. It was noted, that amplitudes of subjects with stroke were larger almost two times than control group’s of healthy subjects. It was find out, that ratios of pressure distribution on both left and right legs are in range from 1 to 0.9 for healthy subjects, and ratios below 0.9 are common for subjects with stroke. When subjects were standing with eyes closed, sway amplitudes were higher and the ratios of load distribution on left and right legs were lower.Article in Lithuanian

  9. Analyzing hydrological sustainability through water balance.

    Science.gov (United States)

    Menció, Anna; Folch, Albert; Mas-Pla, Josep

    2010-05-01

    The objective of the Water Framework Directive (2000/60/EC) is to assist in the development of management plans that will lead to the sustainable use of water resources in all EU member states. However, defining the degree of sustainability aimed at is not a straightforward task. It requires detailed knowledge of the hydrogeological characteristics of the basin in question, its environmental needs, the amount of human water demand, and the opportunity to construct a proper water balance that describes the behavior of the hydrological system and estimates available water resources. An analysis of the water balance in the Selva basin (Girona, NE Spain) points to the importance of regional groundwater fluxes in satisfying current exploitation rates, and shows that regional scale approaches are often necessary to evaluate water availability. In addition, we discuss the pressures on water resources, and analyze potential actions, based on the water balance results, directed towards achieving sustainable water management in the basin. PMID:20229067

  10. Postural balance in low back pain patients

    DEFF Research Database (Denmark)

    Maribo, Thomas; Stengaard-Pedersen, Kristian; Jensen, Lone Donbæk; Andersen, Niels Trolle; Schiøttz-Christensen, Berit

    2011-01-01

    Low back pain (LBP) patients have poorer postural control compared to healthy controls, and the importance of assessing and addressing balance is a matter of debate. In the clinic, balance is often tested by means of the one leg stand test (OLST) while research often employs center of pressure (Co...... (Romberg Ratio) might be of clinical interest. This study aimed to assess postural balance in LBP patients by analyzing intra-session reliability of CoP parameters on a portable force platform, the Romberg Ratio, and the OLST. Furthermore, we aimed to determine whether CoP parameters and OLST measure...... identical aspects of postural stability. We examined 49 LBP patients and found acceptable reliability of the CoP parameters’ trace length and velocity, whereas reliability regarding C90 area, the Romberg Ratio, and the OLST was poor. Correlations between the CoP parameters and OLST were insignificant...

  11. Chromatographic separation and analysis of rare earths

    International Nuclear Information System (INIS)

    It is shown that difficult inorganic separation problems can be solved by a simple and inexpensive method. Examples: 1. Separation of rare earths by means of thin-layer chromatography in analyses of minerals, highest grade materials, and fission products within a fuel element; 2. Separation and quantitative determination of rare earths by means of high-pressure liquid chromatography in analyses of monazite sands, cerium composition metals, and fission products. (RB)

  12. EarthLabs - Investigating Hurricanes: Earth's Meteorological Monsters

    Science.gov (United States)

    McDaris, J. R.; Dahlman, L.; Barstow, D.

    2007-12-01

    Earth science is one of the most important tools that the global community needs to address the pressing environmental, social, and economic issues of our time. While, at times considered a second-rate science at the high school level, it is currently undergoing a major revolution in the depth of content and pedagogical vitality. As part of this revolution, labs in Earth science courses need to shift their focus from cookbook-like activities with known outcomes to open-ended investigations that challenge students to think, explore and apply their learning. We need to establish a new model for Earth science as a rigorous lab science in policy, perception, and reality. As a concerted response to this need, five states, a coalition of scientists and educators, and an experienced curriculum team are creating a national model for a lab-based high school Earth science course named EarthLabs. This lab course will comply with the National Science Education Standards as well as the states' curriculum frameworks. The content will focus on Earth system science and environmental literacy. The lab experiences will feature a combination of field work, classroom experiments, and computer access to data and visualizations, and demonstrate the rigor and depth of a true lab course. The effort is being funded by NOAA's Environmental Literacy program. One of the prototype units of the course is Investigating Hurricanes. Hurricanes are phenomena which have tremendous impact on humanity and the resources we use. They are also the result of complex interacting Earth systems, making them perfect objects for rigorous investigation of many concepts commonly covered in Earth science courses, such as meteorology, climate, and global wind circulation. Students are able to use the same data sets, analysis tools, and research techniques that scientists employ in their research, yielding truly authentic learning opportunities. This month-long integrated unit uses hurricanes as the story line by which students investigate the different interactions involved in hurricane generation, steering, and intensification. Students analyze a variety of visualization resources looking for patterns in occurrence and to develop an understanding of hurricane structure. They download archived data about past hurricanes and produce temporal and spatial plots to discover patterns in hurricane life cycles. They investigate the relationship between hurricane wind speed and factors such as barometric pressure and sea surface temperature by conducting spreadsheet analyses on archived data. They also conduct hands-on laboratory experiments in order to understand the physical processes that underpin energy transfer in convection, condensation, and latent heat. These activities highlight Earth science as a vital, rich, invigorating course, employing state-of-the-art technologies and in-depth labs with high relevance for our daily lives and the future.

  13. Application of Pascal Principle in Earth Science

    Science.gov (United States)

    Samimi Namin, M.

    2009-12-01

    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.

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

    OpenAIRE

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

    2009-01-01

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

  15. The Earth's atmosphere its physics and dynamics

    CERN Document Server

    Saha, Kshudiram

    2008-01-01

    The book entitled ""Atmospheric science and Global Warming"" covers a wide area of the atmospheric science, focusing particularly on those physical and dynamical aspects of our environment which tend to create heat sources and sinks in the earth-atmosphere system and which it seeks to balance through circulation at different time and space scales. The processes of heat transfer in the atmosphere and ocean by general circulation and by waves and oscillations are discussed in detail. The heat balance of the atmosphere is discussed after taking into consideration the role of various types of gree

  16. Martian Atmospheric Pressure Static Charge Elimination Tool

    Science.gov (United States)

    Johansen, Michael R.

    2014-01-01

    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.

  17. 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

  18. Finding Your Balance

    CERN Document Server

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

    2011-01-01

    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

  19. Getting the balance right

    International Nuclear Information System (INIS)

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

  20. Multidimensional spectral load balancing

    Energy Technology Data Exchange (ETDEWEB)

    Hendrickson, B.; Leland, R.

    1993-01-01

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

  1. In the balance

    DEFF Research Database (Denmark)

    Kluth, Michael Friederich; Pilegaard, Jess

    The present paper seeks to make sense of recent EU naval capability changes by applying neo-realist theory on the EU as an international actor in the global balance of power. The paper compares three different strands of Neo-realist theory by deducting key predictions about the expected defense...... posture of the Union and the expected changes in naval capabilities. The predictions are subsequently held up against recent data on naval military build-up in the EU. The paper argues that the observed patterns are best explained not as bandwagoning with the United States, but as a long-term balancing...

  2. Greenland ice sheet mass balance: a review

    DEFF Research Database (Denmark)

    Khan, Shfaqat Abbas; Aschwanden, Andy; Bjørk, Anders A.; Wahr, John; Kjeldsen, Kristian K.; Kjær, Kurt H.

    2015-01-01

    Over the past quarter of a century the Arctic has warmed more than any other region on Earth, causing a profound impact on the Greenland ice sheet (GrIS) and its contribution to the rise in global sea level. The loss of ice can be partitioned into processes related to surface mass balance and to...... and melt-induced mass losses exhibit rapid short-term fluctuations that, when extrapolated into the future, could yield erroneous long-term trends. In this paper we review the GrIS mass loss over more than a century by combining satellite altimetry, airborne altimetry, interferometry, aerial...

  3. Electrokinetically supported pressure casting

    Energy Technology Data Exchange (ETDEWEB)

    Krueger, H.G.; Schindler, U. [Technische Univ. Ilmenau (Germany). Fakultaet fuer Maschinenbau

    2001-02-01

    On the basis of the physical operating principles characterizing electrokinetically supported pressure casting, two different processing arrangements and their relative efficiency are discussed. The investigations were conducted with a porcelain slip in a small-sized laboratory pressure casting plant. A combination of pressure filtration and electrophoresis/electroosmosis is especially effective if the filtrate volume flows of both pressure filtration and electroosmosis have the same direction. This is the case for one-sided filtration, where casting time reductions of 75% could be realized by electrokinetic effects. Furthermore, the electrical field effects enable body shaping at very low shot pressures of 5 or 10 bar. Well-balanced body shaping could be achieved at a pressure of 25 bar and at an electric current density of 7 mA/cm{sup 2}. For double-sided filtration, the filtrate volume flows add to each other only at the cathode side. The filtrate volume flows of pressure filtration and electroosmosis subtract from each other close to the anode, leading to a low amount of filtrate at the anode side. Furthermore, the centre of the symmetrically inwards-directed gradient of moisture, which is the typical situation for pressure casting, is shifted away from the centre of the green body. (orig.)

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

    Directory of Open Access Journals (Sweden)

    Ayşe Oya Erkut Atılgan

    2012-10-01

    Full Text Available The aim of this study was to investigate the relationship between balance lost on balance beam during the series performed by women gymnasts at International Bosphorus Gymnastics Tournament with anthropometric characteristics and static-dynamic balance test scores. 19 female gymnasts (ages 14,53±2,20, training years9,0±3 participated in this research voluntarily. Before the competition, the static and dynamic balance score and anthropometrics values were taken by experienced researchers. In order to analyze balance loss on balance beam routines were evaluated by four international judges. The relationship between balance lost on balance beam and balance abilities were tested by “Pearson Correlation Analysis”. As a result although there were a negative relationship between dynamic balance parameters with age, training experience, some anthropometric features (p<0,05  there were no relationship between static and dynamic balance tests parameters and balance lost on balance beam routines in gymnast (p>0,05. There were high negative relationship between final score and balance lost in balance beam series (p<0,01, there were  no relationship between balance lost in balance beam series and static- dynamic balance parameters (p>0,05. Artistic gymnastics training contribute positively to the improvement of balance skills, which may have enabled the gymnasts to preserve their balances perfectly, even under difficult circumstances. It can be summarized that the ability of the gymnasts in preserving their balances in similar degree, both during competition and during the tests given under laboratory conditions, can be an outcome of their improved balance skills acquired through exercise. 

  5. On the Misdiagnosis of Surface Temperature Feedbacks from Variations in Earths Radiant Energy Balance

    OpenAIRE

    Roy W. Spencer; William D. Braswell

    2011-01-01

    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...

  6. Thermodynamics of the Earth

    Science.gov (United States)

    Stacey, Frank D.

    2010-04-01

    Applications of elementary thermodynamic principles to the dynamics of the Earth lead to robust, quantitative conclusions about the tectonic effects that arise from convection. The grand pattern of motion conveys deep heat to the surface, generating mechanical energy with a thermodynamic efficiency corresponding to that of a Carnot engine operating over the adiabatic temperature gradient between the heat source and sink. Referred to the total heat flux derived from the Earth's silicate mantle, the efficiency is 24% and the power generated, 7.7 × 1012 W, causes all the material deformation apparent as plate tectonics and the consequent geological processes. About 3.5% of this is released in seismic zones but little more than 0.2% as seismic waves. Even major earthquakes are only localized hiccups in this motion. Complications that arise from mineral phase transitions can be used to illuminate details of the motion. There are two superimposed patterns of convection, plate subduction and deep mantle plumes, driven by sources of buoyancy, negative and positive respectively, at the top and bottom of the mantle. The patterns of motion are controlled by the viscosity contrasts (>104 : 1) at these boundaries and are self-selected as the least dissipative mechanisms of heat transfer for convection in a body with very strong viscosity variation. Both are subjects of the thermodynamic efficiency argument. Convection also drives the motion in the fluid outer core that generates the geomagnetic field, although in that case there is an important energy contribution by compositional separation, as light solute is rejected by the solidifying inner core and mixed into the outer core, a process referred to as compositional convection. Uncertainty persists over the core energy balance because thermal conduction is a drain on core energy that has been a subject of diverse estimates, with attendant debate over the need for radiogenic heat in the core. The geophysical approach to thermal physics, especially thermal expansion and the Grüneisen parameter, invokes insights that have disappeared from view in 'mainstream' physics.

  7. The Lifeworld Earth and a Modelled Earth

    Science.gov (United States)

    Juuti, Kalle

    2014-01-01

    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

  8. Strategic Balanced Scorecard Simulation

    DEFF Research Database (Denmark)

    Nielsen, Steen; Nielsen, Erland Hejn

    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 company’s BSC model includes five perspectives and a number of...

  9. Dynamic localized load balancing

    Science.gov (United States)

    Balandin, Sergey I.; Heiner, Andreas P.

    2003-08-01

    Traditionally dynamic load balancing is applied in resource-reserved connection-oriented networks with a large degree of managed control. Load balancing in connectionless networks is rather rudimentary and is either static or requires network-wide load information. This paper presents a fully automated, traffic driven dynamic load balancing mechanism that uses local load information. The proposed mechanism is easily deployed in a multi-vendor environment in which only a subset of routers supports the function. The Dynamic Localized Load Balancing (DLLB) mechanism distributes traffic based on two sets of weights. The first set is fixed and is inverse proportional to the path cost, typically the sum of reciprocal bandwidths along the path. The second weight reflects the utilization of the link to the first next hop along the path, and is therefore variable. The ratio of static weights defines the ideal load distribution, the ratio of variable weights the node-local load distribution estimate. By minimizing the difference between variable and fixed ratios the traffic distribution, with the available node-local knowledge, is optimal. The above mechanism significantly increases throughput and decreases delay from a network-wide perspective. Optionally the variable weight can include load information of nodes downstream to prevent congestion on those nodes. The latter function further improves network performance, and is easily implemented on top of the standard OSPF signaling. The mechanism does not require many node resources and can be implemented on existing router platforms.

  10. Keeping Your Balance

    Science.gov (United States)

    ... and flexible joints play a role in our balance. When we stand “still,” we don’t stand fixed like toy soldiers but sway at our ankles. To do this, our ankles make small adjustments keeping our body weight over our feet. If our ankles are stiff, ...

  11. Quantum detailed balance

    International Nuclear Information System (INIS)

    For infinite quantum systems a family of dissipative maps satisfying the condition of detailed balance is constructed. We conjecture that these maps provide a new way of characterizing the equilibrium states. We prove the conjecture for finite systems and for the infinite free Fermion gas

  12. Maintaining an Environmental Balance

    Science.gov (United States)

    Environmental Science and Technology, 1976

    1976-01-01

    A recent conference of the National Environmental Development Association focused on the concepts of environment, energy and economy and underscored the necessity for balancing the critical needs embodied in these issues. Topics discussed included: nuclear energy and wastes, water pollution control, federal regulations, environmental technology…

  13. 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.)

  14. 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.)

  15. Maintaining an Environmental Balance

    Science.gov (United States)

    Environmental Science and Technology, 1976

    1976-01-01

    A recent conference of the National Environmental Development Association focused on the concepts of environment, energy and economy and underscored the necessity for balancing the critical needs embodied in these issues. Topics discussed included: nuclear energy and wastes, water pollution control, federal regulations, environmental technology

  16. Balancing Chemical Equations.

    Science.gov (United States)

    Savoy, L. G.

    1988-01-01

    Describes a study of students' ability to balance equations. Answers to a test on this topic were analyzed to determine the level of understanding and processes used by the students. Presented is a method to teach this skill to high school chemistry students. (CW)

  17. Yin-Yang Balancing

    DEFF Research Database (Denmark)

    Li, Peter Ping

    The potential contribution of the Eastern frame of Yin-Yang Balancing lies in the mindset of "either/and", in contrast to Aristotle's either/or logic and Hegel's "both/or". Implications of this either/and thinking for science and management will be explored....

  18. 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

  19. Balancing Books & Bytes

    Science.gov (United States)

    Britt, Judy; Brasher, Joe P.; Davenport, Lydia D.

    2007-01-01

    Computers do not replace the need for students to read good books. However, sharing a book can employ contemporary strategies, such as project-based learning, that provide an exciting balance between traditional teaching and technology tools. Heritage teachers ensure that they do not abandon aspects of traditional skill development as they embrace…

  20. Energy balance measurement

    DEFF Research Database (Denmark)

    Dhurandhar, N V; Schoeller, D; Brown, A W; Heymsfield, S B; Thomas, D; Sørensen, T I A; Speakman, J R; Jeansonne, M; Allison, D B

    2015-01-01

    Energy intake (EI) and physical activity energy expenditure (PAEE) are key modifiable determinants of energy balance, traditionally assessed by self-report despite its repeated demonstration of considerable inaccuracies. We argue here that it is time to move from the common view that self-reports...

  1. Frihed, anerkendelse og balance

    DEFF Research Database (Denmark)

    Anker, Thomas Boysen

    Artiklen argumenterer for, at selv ikke den absolut mest familievenlige arbejdsplads vil kunne løse det psykologiske problem med at skabe balance mellem familie og arbejdsliv, fordi ubalancen grundlæggende handler om en anerkendelseskonflikt, som individet ikke altid selv er interesseret i at komme...

  2. National Energy Balance - 1986

    International Nuclear Information System (INIS)

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

  3. 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.)

  4. Pressure Dome for High-Pressure Electrolyzer

    Science.gov (United States)

    Norman, Timothy; Schmitt, Edwin

    2012-01-01

    A high-strength, low-weight pressure vessel dome was designed specifically to house a high-pressure [2,000 psi (approx. = 13.8 MPa)] electrolyzer. In operation, the dome is filled with an inert gas pressurized to roughly 100 psi (approx. = 690 kPa) above the high, balanced pressure product oxygen and hydrogen gas streams. The inert gas acts to reduce the clamping load on electrolyzer stack tie bolts since the dome pressure acting axially inward helps offset the outward axial forces from the stack gas pressure. Likewise, radial and circumferential stresses on electrolyzer frames are minimized. Because the dome is operated at a higher pressure than the electrolyzer product gas, any external electrolyzer leak prevents oxygen or hydrogen from leaking into the dome. Instead the affected stack gas stream pressure rises detectably, thereby enabling a system shutdown. All electrical and fluid connections to the stack are made inside the pressure dome and require special plumbing and electrical dome interfaces for this to be accomplished. Further benefits of the dome are that it can act as a containment shield in the unlikely event of a catastrophic failure. Studies indicate that, for a given active area (and hence, cell ID), frame outside diameter must become ever larger to support stresses at higher operating pressures. This can lead to a large footprint and increased costs associated with thicker and/or larger diameter end-plates, tie-rods, and the frames themselves. One solution is to employ rings that fit snugly around the frame. This complicates stack assembly and is sometimes difficult to achieve in practice, as its success is strongly dependent on frame and ring tolerances, gas pressure, and operating temperature. A pressure dome permits an otherwise low-pressure stack to operate at higher pressures without growing the electrolyzer hardware. The pressure dome consists of two machined segments. An O-ring is placed in an O-ring groove in the flange of the bottom segment and is trapped by the flange on the top dome segment when these components are bolted together with high-strength bolts. The pressure dome has several unique features. It is made (to ASME Pressure Vessel guidelines) in a high-strength aluminum alloy with the strength of stainless steel and the weight benefits of aluminum. The flange of the upper dome portion contains specially machined flats for mounting the dome, and other flats dedicated to the special feedthroughs for electrical connections. A pressure dome can be increased in length to house larger stacks (more cells) of the same diameter with the simple addition of a cylindrical segment. To aid in dome assembly, two stainless steel rings are employed. One is used beneath the heads of the high-strength bolts in lieu of individual hardened washers, and another is used instead of individual nuts. Like electrolyzers could be operated at low or high pressures simply by operating the electrolyzer outside or inside a pressurized dome.

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

    Directory of Open Access Journals (Sweden)

    Salih Pınar

    2012-10-01

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

  6. 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

  7. NASA Earth Exchange (NEX)

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA Earth Exchange (NEX) represents a new platform for the Earth science community that provides a mechanism for scientific collaboration and knowledge...

  8. EarthKAM

    Data.gov (United States)

    National Aeronautics and Space Administration — Sponsored by NASA, EarthKAM (Earth Knowledge Acquired by Middle School Students) is an educational outreach program allowing middle school students to take pictures...

  9. Improving Balance Function Using Low Levels of Electrical Stimulation of the Balance Organs

    Science.gov (United States)

    Bloomberg, Jacob; Reschke, Millard; Mulavara, Ajitkumar; Wood, Scott; Serrador, Jorge; Fiedler, Matthew; Kofman, Igor; Peters, Brian T.; Cohen, Helen

    2012-01-01

    Crewmembers returning from long-duration space flight face significant challenges due to the microgravity-induced inappropriate adaptations in balance/ sensorimotor function. The Neuroscience Laboratory at JSC is developing a method based on stochastic resonance to enhance the brain s ability to detect signals from the balance organs of the inner ear and use them for rapid improvement in balance skill, especially when combined with balance training exercises. This method involves a stimulus delivery system that is wearable/portable providing imperceptible electrical stimulation to the balance organs of the human body. Stochastic resonance (SR) is a phenomenon whereby the response of a nonlinear system to a weak periodic input signal is optimized by the presence of a particular non-zero level of noise. This phenomenon of SR is based on the concept of maximizing the flow of information through a system by a non-zero level of noise. Application of imperceptible SR noise coupled with sensory input in humans has been shown to improve motor, cardiovascular, visual, hearing, and balance functions. SR increases contrast sensitivity and luminance detection; lowers the absolute threshold for tone detection in normal hearing individuals; improves homeostatic function in the human blood pressure regulatory system; improves noise-enhanced muscle spindle function; and improves detection of weak tactile stimuli using mechanical or electrical stimulation. SR noise has been shown to improve postural control when applied as mechanical noise to the soles of the feet, or when applied as electrical noise at the knee and to the back muscles.

  10. Setting the Pressure at Which to Conduct a Distillation.

    Science.gov (United States)

    Barduhn, Allen J.

    1984-01-01

    Discusses how pressure setting is determined for distillation columns, examining factors which must be considered when optimizing design for economical balance. Also discusses the basics of heat exchangers and cites a common problem with pressure differences. (JM)

  11. Rigidly rotating dust with magnetic pressure in general relativity

    International Nuclear Information System (INIS)

    Rigidly rotating pressure-free matter interacting with an electromagnetic field is studied under the assumption that in the co-rotating frame the gravitational attraction is balanced by the centrifugal force and by magnetic pressure. (author)

  12. Rare earth elements

    International Nuclear Information System (INIS)

    Present article is devoted to content of rare earth elements in fluorite. The data on content of rare earth elements in fluorite was systematized and generalized. The 446 analysis results were used. The rare earth elements content in fluorite of geologic deposits of various mineralogical and genetic type was defined.

  13. 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

  14. 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

  15. 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.)

  16. An ideal balance?

    OpenAIRE

    Mair, Jane

    2013-01-01

    Considers the intersection between employment policy and family law, and the changes in work and family regarding traditional gender roles. Examines UK and EU policy initiatives aimed at achieving a better work/life balance for employees with children. Argues that many of the policy aspirations are predicated on an equal opportunities employment model that may not exist in practice and also fail to reflect the realities of family life.

  17. Balance-bot

    OpenAIRE

    Abreu, Victor Vicente

    2009-01-01

    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. Control...

  18. France's energy balances

    International Nuclear Information System (INIS)

    Several terminological definitions of words and concepts used for the establishment of France's energy balance (i.e. the supply and utilization of energy) are presented, taken from the Energy dictionary, published in 1992 by the world Energy Council: primary, secondary, final and useful energy. Statistics concerning energy production, importation and exportation, consumption, and costs are discussed, showing the market share evolution of the different energy types; the France's energy independence ratio has increased from 22% in 1973 to 51% in 1995

  19. Finance and Balanced Growth

    OpenAIRE

    Trew, Alex

    2010-01-01

    We study the relationships between various concepts of financial development and balanced economic growth. A model of endogenous growth that incorporates roles for both financial efficiency and access to financial services permits a better understanding of the relationship between the size of the financial sector (value added) and growth. Higher financial value added results from some, but not all, kinds of finance-driven growth. If greater access rather than greater efficiency generates high...

  20. Balancing Trust and Control

    DEFF Research Database (Denmark)

    Jagd, Søren

    This paper focuses on the leadership challenge of balancing trust and control. The relation between trust and control has for a long time been a puzzling issue for management researchers. In the paper I first show that there has been a dramatic change in the way the relation between trust and con...... paper concludes by illustrating how this more fine grained understanding of the intertwining of trust and control is helpful for the understanding of the interplay of trust, control and self-control in new forms of organizations.......This paper focuses on the leadership challenge of balancing trust and control. The relation between trust and control has for a long time been a puzzling issue for management researchers. In the paper I first show that there has been a dramatic change in the way the relation between trust and...... control has been conceptualized in trust research. While the relation between trust and control earlier was conceptualized as a more or less stable balance between trust and control, more recent research conceptualizes the relation between trust and control more as a dynamical process that involves an...

  1. Simple Cell Balance Circuit

    Science.gov (United States)

    Johnson, Steven D.; Byers, Jerry W.; Martin, James A.

    2012-01-01

    A method has been developed for continuous cell voltage balancing for rechargeable batteries (e.g. lithium ion batteries). A resistor divider chain is provided that generates a set of voltages representing the ideal cell voltage (the voltage of each cell should be as if the cells were perfectly balanced). An operational amplifier circuit with an added current buffer stage generates the ideal voltage with a very high degree of accuracy, using the concept of negative feedback. The ideal voltages are each connected to the corresponding cell through a current- limiting resistance. Over time, having the cell connected to the ideal voltage provides a balancing current that moves the cell voltage very close to that ideal level. In effect, it adjusts the current of each cell during charging, discharging, and standby periods to force the cell voltages to be equal to the ideal voltages generated by the resistor divider. The device also includes solid-state switches that disconnect the circuit from the battery so that it will not discharge the battery during storage. This solution requires relatively few parts and is, therefore, of lower cost and of increased reliability due to the fewer failure modes. Additionally, this design uses very little power. A preliminary model predicts a power usage of 0.18 W for an 8-cell battery. This approach is applicable to a wide range of battery capacities and voltages.

  2. Capturing Near Earth Objects

    OpenAIRE

    Baoyin, Hexi; Chen, Yang; Li, Junfeng

    2011-01-01

    Recently, Near Earth Objects (NEOs) have been attracting great attention, and thousands of NEOs have been found to date. This paper examines the NEOs' orbital dynamics using the framework of an accurate solar system model and a Sun-Earth-NEO three-body system when the NEOs are close to Earth to search for NEOs with low-energy orbits. It is possible for such an NEO to be temporarily captured by Earth; its orbit would thereby be changed and it would become an Earth-orbiting object after a small...

  3. The cardiac blood supply-workload balance in children.

    Science.gov (United States)

    Murakami, Tomoaki; Takeda, Atsuhito; Takei, Kohta; Tateno, Shigeru; Kawasoe, Yasutaka; Niwa, Koichiro

    2015-09-01

    It is well known that the reflected pressure wave in small children returns earlier than that in adolescent. The reason of early return of the reflected pressure wave in infancy is their height. The short distance between heart and reflection point makes the reflected pressure wave returning to the heart earlier. In adult, the early return (during systole) of the reflected pressure wave means disadvantage to cardiac blood supply-workload balance. The purpose of this study was to clarify whether the early return of the reflected pressure wave in small children impairs the cardiac blood supply-workload balance. This study enrolled 37 small left-to-right shunt patients with normal aortic circulation below 15 years of age. The aortic pressure waveform was recorded using a pressure sensor mounted catheter, and augmentation index and subendocardial viability ratio were calculated. The age of patients was 6.1 ± 3.2 years. The augmentation index was 8.7 ± 14.3 % and the index had a negative correlation with patients' age (r = -0.6243, p balance, was 0.92 ± 0.14 and the index had a positive relationship with patients' age (r = 0.6435, p balance gradually improves from infancy to young adulthood. One of the causes of the unfavorable cardiac blood supply-workload balance in infancy would be the accelerated aortic pressure wave reflection due to their short height. PMID:24989969

  4. The balanced scorecard: sustainable performance assessment for forensic laboratories.

    Science.gov (United States)

    Houck, Max; Speaker, Paul J; Fleming, Arron Scott; Riley, Richard A

    2012-12-01

    The purpose of this article is to introduce the concept of the balanced scorecard into the laboratory management environment. The balanced scorecard is a performance measurement matrix designed to capture financial and non-financial metrics that provide insight into the critical success factors for an organization, effectively aligning organization strategy to key performance objectives. The scorecard helps organizational leaders by providing balance from two perspectives. First, it ensures an appropriate mix of performance metrics from across the organization to achieve operational excellence; thereby the balanced scorecard ensures that no single or limited group of metrics dominates the assessment process, possibly leading to long-term inferior performance. Second, the balanced scorecard helps leaders offset short term performance pressures by giving recognition and weight to long-term laboratory needs that, if not properly addressed, might jeopardize future laboratory performance. PMID:23068771

  5. Earth Science Information Center

    Science.gov (United States)

    U.S. Geological Survey

    1991-01-01

    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.

  6. Instrumented Static and Dynamic Balance Assessment after Stroke Using Wii Balance Boards: Reliability and Association with Clinical Tests

    OpenAIRE

    Bower, Kelly J.; McGinley, Jennifer L.; Miller, Kimberly J.; Clark, Ross A.

    2014-01-01

    Background and Objectives The Wii Balance Board (WBB) is a globally accessible device that shows promise as a clinically useful balance assessment tool. Although the WBB has been found to be comparable to a laboratory-grade force platform for obtaining centre of pressure data, it has not been comprehensively studied in clinical populations. The aim of this study was to investigate the measurement properties of tests utilising the WBB in people after stroke. Methods Thirty individuals who were...

  7. A Simple Approach to Dynamic Material Balance in Gas-Condensate Reservoirs

    OpenAIRE

    Heidari Sureshjani M.; Gerami S.; Emadi M.A.

    2013-01-01

    In traditional material balance calculations, shut-in well pressure data are used to determine average reservoir pressure while recent techniques do not require the well to be shut-in and use instead flowing well pressure-rate data. These methods, which are known as “dynamic” material balance, are developed for single-phase flow (oil or gas) in reservoirs. However, utilization of such methods for gas-condensate reservoirs may create ...

  8. Effects of insoles contact on static balance

    Science.gov (United States)

    Shin, Ju Yong; Ryu, Young Uk; Yi, Chae Woo

    2016-01-01

    [Purpose] This study examined the effect of the degree of the contact area between the insoles and soles on static balance. [Subjects and Methods] Thirteen healthy male and female adults voluntarily participated. All of the subjects wore three different types of insoles (no orthotic insole, partial contact, full contact) in the present experiment. The subjects were instructed to place both feet parallel to each other and maintain static balance for 30 seconds. Center of pressure parameters (range, total distance, and mean velocity) were analyzed. [Results] The results show that the anteroposterior range and mediolateral (ML) total distance and velocity decreased when orthotic insoles with partial contact or full contact were used in comparison to when a flat insole (no orthotic insole) was used. Also, the ML range and total distance were lower with full contact than in the other two conditions. These results indicate that static balance improves as the degree of contact between the soles and insoles increases. [Conclusion] The results of this study suggests that using insoles with increased sole contact area would improve static balance ability.

  9. Balancing mechanism status: June 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 June 2009. (J.S.)

  10. Balancing mechanism status: November 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 November 2009. (J.S.)

  11. Balancing mechanism status: December 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 December 2009. (J.S.)

  12. Balancing mechanism status: September 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 September 2009. (J.S.)

  13. Balancing mechanism status: August 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 August 2009. (J.S.)

  14. Balancing mechanism status: February 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 February 2009. (J.S.)

  15. Balancing mechanism status: July 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 July 2009. (J.S.)

  16. Balancing mechanism status: October 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 October 2009. (J.S.)

  17. Balanced skills among nascent entrepreneurs

    OpenAIRE

    Stuetzer, Michael; Obschonka, Martin; Schmitt-Rodermund, Eva

    2012-01-01

    This paper examines the effects and origins of balanced skills among nascent entrepreneurs. In a first step we apply Lazear’s jack-of-all-trades theory to investigate performance effects of a balanced skill set. Second, we investigate potential sources of balanced skills, thereby testing the investment hypothesis against the endowment hypothesis. Analyzing data on high-potential nascent projects, we find support for the notion that balanced skills are important for making progress in the vent...

  18. Wind-Tunnel Balance Characterization for Hypersonic Research Applications

    Science.gov (United States)

    Lynn, Keith C.; Commo, Sean A.; Parker, Peter A.

    2012-01-01

    Wind-tunnel research was recently conducted at the NASA Langley Research Center s 31-Inch Mach 10 Hypersonic Facility in support of the Mars Science Laboratory s aerodynamic program. Researchers were interested in understanding the interaction between the freestream flow and the reaction control system onboard the entry vehicle. A five-component balance, designed for hypersonic testing with pressurized flow-through capability, was used. In addition to the aerodynamic forces, the balance was exposed to both thermal gradients and varying internal cavity pressures. Historically, the effect of these environmental conditions on the response of the balance have not been fully characterized due to the limitations in the calibration facilities. Through statistical design of experiments, thermal and pressure effects were strategically and efficiently integrated into the calibration of the balance. As a result of this new approach, researchers were able to use the balance continuously throughout the wide range of temperatures and pressures and obtain real-time results. Although this work focused on a specific application, the methodology shown can be applied more generally to any force measurement system calibration.

  19. More on Chemical Reaction Balancing.

    Science.gov (United States)

    Swinehart, D. F.

    1985-01-01

    A previous article stated that only the matrix method was powerful enough to balance a particular chemical equation. Shows how this equation can be balanced without using the matrix method. The approach taken involves writing partial mathematical reactions and redox half-reactions, and combining them to yield the final balanced reaction. (JN)

  20. Accretion and Core-Mantle Differentiation of the Earth and Other Terrestrial Planets

    Science.gov (United States)

    Jacobson, Seth A.; Rubie, David C.; Morbidelli, Alessandro; O'Brien, David P.; Young, Edward D.; de Vries, Jellie; Nimmo, Francis; Palme, Herbert; Frost, Dan J.

    2014-11-01

    Using a multi-stage core-mantle differentiation model that incorporates over 250 Grand Tack N-body simulations, we have studied the growth of the Earth’s mantle and core as well as those of Mars, Venus and the embryos, which impacted the Earth (i.e. the proto-lunar impactor Theia). The Grand Tack is the terrestrial planet formation scenario that most successfully matches dynamic and simple compositional constraints. During this scenario, Jupiter and Saturn migrate inwards and then outwards through the inner Solar System. The Earth grows due to the accretion of planetesimals and embryos from throughout the inner disk and from a disk of planetesimals exterior to Jupiter and Saturn, which are scattered inward by their migration. The core-mantle differentiation model uses chemical mass balance and metal-silicate element partitioning data to determine the mantle and core compositions as the Earth grows. Treating the initial oxidation state of the original bodies as free parameters, taking the composition of the Earth’s primitive mantle as a constraint, and assuming that the non-volatile elements are present in Solar System (CI) relative abundances, we use least squares refinement to fit the metal-silicate equilibration pressure, the disequilibrium fraction of projectile cores and 4 parameters defining an initial oxidation gradient in the inner Solar System. Consistent with the Grand Tack scenario’s explanation of the C-type asteroids originating from the outer Solar System, water is delivered from only these bodies. We find that that the accreting Earth evolves in time—accreting increasingly oxidized material and changing the oxidation state of the Earth’s mantle, and that the metal-silicate equilibration pressures are about 60-70% of the core-mantle boundary pressures and nearly all of the metal in each projectile core equilibrates with the some portion of the planet’s silicate mantle. The best fits are found when the planetesimals and embryos closest to the Sun are highly reduced and those further out are increasingly oxidized. Venus is found to be very similar to the Earth, and the FeO content of the Martian mantle depends critically on the location of the original location of its stranded embryo nucleus.

  1. LINE BALANCING IN SERVICES

    Directory of Open Access Journals (Sweden)

    Hadi GKEN

    2002-01-01

    Full Text Available This paper investigates how the Assembly Line Balancing (ALB methods known for the production systems can be applied in service systems. For this purpose, an application study is done in a Physical therapy and rehabilitation clinic. Each standart service provided to patients is taken into consideration as a product, and problem is solved as a mixed model ALB problem. In conclusion, it is seen that the ALB methods developed for the production systems are also applicable in service systems. So, it is possible to do similar studies at hospitals, tax offices, driving licence and passport offices, fast food restaurants, etc.

  2. Balancing beyond the horizon?

    DEFF Research Database (Denmark)

    Kluth, Michael Friederich; Pilegaard, Jess

    2011-01-01

    The present article seeks to make sense of recent European Union (EU) naval capability changes by applying neo-realist theory to the EU as a collective actor in the global balance of power. The paper compares two different strands of neorealist theory by deducing key predictions about the expected...... naval posture of the Union and the corresponding expected changes in capabilities. These predictions are subsequently held up against post-cold war data on naval acquisitions in the EU. The paper concludes that the observed patterns are best explained not as bandwagoning with the USA, but as a long...

  3. Kin Selection - Mutation Balance

    DEFF Research Database (Denmark)

    Dyken, J. David Van; Linksvayer, Timothy Arnold; Wade, Michael J.

    2011-01-01

    selection-mutation balance, which provides an evolutionary null hypothesis for the statics and dynamics of cheating. When social interactions have linear fitness effects and Hamilton´s rule is satisfied, selection is never strong enough to eliminate recurrent cheater mutants from a population, but cheater...... lineages are transient and do not invade. Instead, cheating lineages are eliminated by kin selection but are constantly reintroduced by mutation, maintaining a stable equilibrium frequency of cheaters. The presence of cheaters at equilibrium creates a "cheater load" that selects for mechanisms of cheater...

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

    OpenAIRE

    Ayşe Oya Erkut Atılgan; Manolya Akın; Ufuk Alpkaya; Salih Pınar

    2012-01-01

    The aim of this study was to investigate the relationship between balance lost on balance beam during the series performed by women gymnasts at International Bosphorus Gymnastics Tournament with anthropometric characteristics and static-dynamic balance test scores. 19 female gymnasts (ages 14,53±2,20, training years9,0±3) participated in this research voluntarily. Before the competition, the static and dynamic balance score and anthropometrics values were taken by experienced researchers. In ...

  5. Canopy edge flow: A momentum balance analysis

    Science.gov (United States)

    Moltchanov, Sharon; Bohbot-Raviv, Yardena; Duman, Tomer; Shavit, Uri

    2015-04-01

    Canopy flow models are often dedicated to ideal, infinite, homogenous systems. However, real canopy systems have physical boundaries, where the flow enters and leaves patches of vegetation, generating a complex pressure field and velocity variations. Here we focus our study on the canopy entry region by examining the terms involved in the double (space and time) averaged momentum equations and their relative contribution to the total momentum balance. The estimation of each term is made possible by particle image velocimetry (PIV) measurements in a model canopy constructed of randomly distributed thin glass plates. The instantaneous velocity fields were used to calculate the mean velocities, pressure, drag, Reynolds stresses, and dispersive stresses. It was found that within the entry region, the pressure gradient, the drag forces, and dispersive stresses are the three most significant terms that affect the balance in the streamwise momentum equation. In the vertical direction, the dispersive stresses are also significant and their contribution to the total momentum cannot be ignored. The study shows that dispersive stresses are initially formed around canopy edges; at both the entry region and the canopy top boundary. They start as a sink term, extracting momentum from the flow, and then become a source term that contributes momentum to the flow until they eventually decay at some short penetration distance into the canopy. These results reveal a new understanding on the evolution of momentum within the entry region, necessary in any closure modeling of flow in real canopies.

  6. Digital Earth – A sustainable Earth

    International Nuclear Information System (INIS)

    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

  7. Entropy of balance - some recent results

    Directory of Open Access Journals (Sweden)

    Laxback Gerd

    2010-07-01

    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.

  8. Pressure Sores

    Science.gov (United States)

    ... and dry Changing position every two hours Using pillows and products that relieve pressure Pressure sores have a variety of treatments. Advanced sores are slow to heal, so early treatment is best.

  9. Pressure ulcers.

    Science.gov (United States)

    O'Byrne, Deborah

    2016-04-13

    My nursing experience is in acute care. Acute medical nurses are well placed to assess skin integrity, identify patients at risk of pressure ulcer development, and commence appropriate interventions to prevent or treat pressure ulcers. PMID:27073966

  10. Negative leave balances

    CERN Multimedia

    Human Resources Department

    2005-01-01

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

  11. Negative leave balances

    CERN Multimedia

    Human Resources Department

    2005-01-01

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

  12. Near Earth Objects

    OpenAIRE

    Wolff, Stefan

    2006-01-01

    The word planet comes from Greek planetes, wanderers, because the planets appear to wander across the celestial sphere, contrary to the fixed stars. This thesis presents several methods for using this motion to distinguish between stars and solar system objects in order to detect and track NEOs, Near Earth Objects: Asteroids and comets following paths that bring them near the Earth. NEOs have collided with the Earth since its formation, some causing local devastation, some causing global clim...

  13. The Earth's Magnetic Field

    OpenAIRE

    Edda Lna Gunnarsdttir 1988

    2012-01-01

    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...

  14. Balance ability and athletic performance.

    Science.gov (United States)

    Hrysomallis, Con

    2011-03-01

    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

  15. Pressure ulcer

    Science.gov (United States)

    Bedsore; Decubitus ulcer ... form. You are more likely to get a pressure ulcer if you: Use a wheelchair or stay in ... Symptoms of a pressure ulcer are: Red skin that gets worse over time The area forms a blister, then an open sore Pressure sores ...

  16. The Earth: Present Scenario

    OpenAIRE

    Nishad Gopal Deshpande

    2009-01-01

    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 Earths life cycle. The choices we make today will determine the life on the Earth, tomorrow. Problems that are been created by us and the consequences we are going to face are discussed in length. Some statistical data is provided to get a brief idea. Measure/prevention(s) to combat the upcoming problems have been putforth.

  17. Rare earths; Seltene Erden

    Energy Technology Data Exchange (ETDEWEB)

    Liedtke, Maren; Elsner, Harald [Bundesanstalt fuer Geowissenschaften und Rohstoffe (BGR), Hannover (Germany). Fachbereich Wirtschaftsgeologie der mineralischen Rohstoffe

    2010-03-15

    Because of their user in high tech products rare earths have attracted considerable economic interest in recent years. PR China produces over 95% of the mined output of rare earths. Increasing demand and possible further tightening of the trade restrictions on rare earths by PR China could lead to bottlenecks in supply. Mining projects which will probably lead to production in the near future, are currently at an advanced planning stage in particular Australia, the USA and Canada. Two important rare earth deposits are known in Europe. (orig.)

  18. Rare earths production and marketing opportunities

    International Nuclear Information System (INIS)

    The rare earths (RE) market is relatively small. The total production during 1968 was only 10000 tons (REO) which rose to 27000 tons (REO) during 1985. The three major areas of application, which are volume market for ceric rare earths are catalysts, glass ceramics and metallurgy. Among the other uses of rare earths, the permanent magnets, lamp phosphors and fine ceramics have registered significant growth in RE consumption. Monazite and bastnasite are the main natural source for rare earths and processing of these for one of the rare earths in high demand leads to over production of some others not in demand, thus creating a balance problem. The growth in RE market has always been influenced by the technology shifts and product substitution. For example, the RE consumption during 1974/76 for desulfurization of steel had substantially decreased due to the usage of calcium. Similarly, 1985 had witnessed a drastic cut in the use of REs in fluid cracking due to the introduction of stabilized zeolites which contain less REO. Thus, the overall compound growth rate of demand was only 3.9 % per year during the period 1970-1985. At present, 37 % of the rare earths production goes to the glass/ceramics industry, 33 % for catalyst and 25 % to metallurgy. The price of REs constantly shows a downward trend. This trend coupled with the rapid changes taking place in the various technological fields, demands greater flexibility and high marketing skills from the RE producers. The key factor for future expansion of RE market will be the development of 'high volume' application of ceric rare earths. (author) 2 figs., 8 tabs

  19. Optimized balance rehabilitation training strategy for the elderly through an evaluation of balance characteristics in response to dynamic motions.

    Science.gov (United States)

    Jung, HoHyun; Chun, Keyoung Jin; Hong, Jaesoo; Lim, Dohyung

    2015-01-01

    Balance is important in daily activities and essential for maintaining an independent lifestyle in the elderly. Recent studies have shown that balance rehabilitation training can improve the balance ability of the elderly, and diverse balance rehabilitation training equipment has been developed. However, there has been little research into optimized strategies for balance rehabilitation training. To provide an optimized strategy, we analyzed the balance characteristics of participants in response to the rotation of a base plate on multiple axes. Seven male adults with no musculoskeletal or nervous system-related diseases (age: 25.5±1.7 years; height: 173.9±6.4 cm; body mass: 71.3±6.5 kg; body mass index: 23.6±2.4 kg/m(2)) were selected to investigate the balance rehabilitation training using customized rehabilitation equipment. Rotation of the base plate of the equipment was controlled to induce dynamic rotation of participants in the anterior-posterior, right-diagonal, medial-lateral, and left-diagonal directions. We used a three-dimensional motion capture system employing infrared cameras and the Pedar Flexible Insoles System to characterize the major lower-extremity joint angles, center of body mass, and center of pressure. We found statistically significant differences between the changes in joint angles in the lower extremities in response to dynamic rotation of the participants (P0.05). These results indicate that optimizing rotation control of the base plate of balance rehabilitation training equipment to induce anterior-posterior and medial-lateral dynamic rotation preferentially can lead to effective balance training. Additional tests with varied speeds and ranges of angles of base plate rotation are expected to be useful as well as an analysis of the balance characteristics considering a balance index that reflects the muscle activity and cooperative characteristics. PMID:26508847

  20. A Reconciled Estimate of Ice-Sheet Mass Balance

    Science.gov (United States)

    Shepherd, Andrew; Ivins, Erik R.; A, Geruo; Barletta, Valentina R.; Bentley, Mike J.; Bettadpur, Srinivas; Briggs, Kate H.; Bromwich, David H.; Forsberg, Ren; 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; Srensen, 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

    2012-11-01

    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 Earths polar ice sheets. We find that there is good agreement between different satellite methodsespecially in Greenland and West Antarcticaand 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.

  1. balance del 2007

    Directory of Open Access Journals (Sweden)

    Emilio lvarez Icaza

    2008-01-01

    Full Text Available La Comisin de Derechos Humanos del Distrito Federal (CDHDF, en el presente artculo, busca realizar un balance de los principales avances, problemticas y retos que en el mbito de los derechos humanos se enfrentaron en el 2007. Enmarcados en un hecho sin precedente en el mbito estatal, se puso en marcha el proceso de construccin del Diagnstico y Programa de Derechos Humanos del Distrito Federal, esfuerzo que constituye un punto de partida comn para instancias pblicas, acadmicas y organismos de la sociedad civil en el DF, que favorecer directamente a todas las personas que habitan y transitan esta ciudad, y que sin duda constituye una experiencia indita e innovadora que aspira a convertirse en referente local, nacional e internacional.

  2. Virtual Acts of Balance!

    DEFF Research Database (Denmark)

    Madsen, Anders Koed

    2013-01-01

    especially emphasized how technical web-ontologies implicitly carries with them deeper philosophical ontologies about phanomena such as 'politic', 'scientific intentionality' and 'freedom'. The compromise between these technical influences and the social intentions is described as a 'virtual act of balance......This paper presents an analysis of official documents and white papers pertaining to the two web-portals The Policy Grid Project and FEED that are launched by the UK and the EU respectively. The aim of the portals is to filter and synthesize information relevant for policy discussions and thereby...... policy-making process is formalized. This kind of information-processing makes software increasingly powerful and there is therefore a need for the 'e-governance community' to be reflexive about this development and constantly ponder the trade-offs between structured semantics and looser types of...

  3. A Balancing Act?

    DEFF Research Database (Denmark)

    Gerstlberger, Wolfgang; Stampe, Ian; Knudsen, Mette Præst

    2009 European Manufacturing Survey for the Danish sub-sample including 335 manufacturing firms. Through factor analysis, the paper confirms three main focus areas of new product development in relation to production facilities: efficiency considerations, market attention and greening of innovation....... Logistic regression analysis demonstrates that while market attention is important for new product development, green aspects of innovation and efficiency considerations for innovation are important for the energy efficiency of the production companies. Combining these models highlights that energy...... efficiency moderates the effect of market attention on new product development. The paper therefore concludes that product innovation and energy efficiency is a balancing act, focusing on one will have detrimental effects on the other! These findings point to the conclusion that researchers and practitioners...

  4. Energy balance climate models

    Science.gov (United States)

    North, G. R.; Cahalan, R. F.; Coakley, J. A., Jr.

    1981-01-01

    An introductory survey of the global energy balance climate models is presented with an emphasis on analytical results. A sequence of increasingly complicated models involving ice cap and radiative feedback processes are solved, and the solutions and parameter sensitivities are studied. The model parameterizations are examined critically in light of many current uncertainties. A simple seasonal model is used to study the effects of changes in orbital elements on the temperature field. A linear stability theorem and a complete nonlinear stability analysis for the models are developed. Analytical solutions are also obtained for the linearized models driven by stochastic forcing elements. In this context the relation between natural fluctuation statistics and climate sensitivity is stressed.

  5. Balancing Trust and Control

    DEFF Research Database (Denmark)

    Jagd, Søren

    2010-01-01

    control in organizations. The paper examines recent literature on the conceptualization of the relation between trust and control in and between organizations. The literature review shows that trust and control has been conceptualized as either substituting or complementing each other. Further, it is......The purpose of this paper is to show that conceptualizing trust and control as interactively related processes, as opposed to more static conceptualizations of the two concepts and the relations between them, adds importantly towards understanding the challenges involved in balancing of trust and...... found that the complementary/substitution debate calls for an explicit conceptualization of the relation between trust and control as an interactive process, in contrast to earlier conceptualizations of trust and control as two relatively static and isolated concepts. While the static perspective on...

  6. The balanced mind

    DEFF Research Database (Denmark)

    Allen, Micah; Smallwood, Jonathan; Christensen, Joanna; Gramm, Daniel; Rasmussen, Beinta; Jensen, Christian Gaden; Roepstorff, Andreas; Lutz, Antoine

    2013-01-01

    -wandering on response inhibition and monitoring, using the Error Awareness Task (EAT). We expected to replicate links between TUT and reduced inhibition, and explored whether variance in TUT would predict improved error monitoring, reflecting a capacity to balance between internal and external cognition. By...... analyzing BOLD responses to subjective probes and the EAT, we dissociated contributions of the DMN, executive, and salience networks to task performance. While both response inhibition and online TUT ratings modulated BOLD activity in the medial prefrontal cortex (mPFC) of the DMN, the former recruited a...... during error awareness, supporting a link between monitoring and TUTs. Altogether our results suggest that although TUT is detrimental to task performance, fluctuations in attention between self-generated and external task-related thought is a characteristic of individuals with greater metacognitive...

  7. Work-life balance

    Energy Technology Data Exchange (ETDEWEB)

    Roche, Pat

    2011-03-15

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

  8. Balancing responsibility for sanitation.

    Science.gov (United States)

    Allison, Maria Clasina

    2002-11-01

    In response to the failure of existing means of service provision, environmental health policy is increasingly adopting a framework of governance for providing sanitation. Governance refers to the patterns of interaction between civil society and government. It is viewed here in terms of four dimensions: political, institutional, technical and cultural. The interactions are often described as partnerships and imply a balancing of joint responsibility. A number of issues can be identified in the literature as requiring consideration when adopting a joint responsibility for environmental health issues. These include, the need to distinguish between community and individual rights; the extent to which there is a shared interest in a community rights issues; the institutional framework for upholding the rights of citizens and the need to guard against new inequalities. The research question was: what are the factors that may inhibit or promote the involvement of community-based organisations (CBOs) in the sanitation provision process? From October 1996 to March 1997, an exploration of these factors was conducted in Cape Town, South Africa. A multiple-case study, with an embedded design, of two CBOs was conducted. This paper focuses on the extent to which there was a shared responsibility between local government and CBOs towards sanitation provision in the context of a bill rights which provides people with a right to a healthy living environment. It was found that institutional and technical capacity, political will and cultural diversity will impact on the balance between rights and responsibility. The four dimensional framework of governance is thus a useful tool for exploring the dynamic and diverse nature of environmental health. PMID:12297240

  9. The Earth Charter

    Science.gov (United States)

    Journal of Education for Sustainable Development, 2010

    2010-01-01

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

  10. Evolution and Earth's Entropy

    OpenAIRE

    Klauber, Robert D.

    2010-01-01

    Entropy decreases on the Earth due to day/night temperature differences. This decrease exceeds the decrease in entropy on the Earth related to evolution by many orders of magnitude. Claims by creationists that science is somehow inconsistent with regard to evolution are thus show to be baseless.

  11. Earth Flyby Anomalies

    OpenAIRE

    Nieto, Michael Martin; Anderson, John D.

    2009-01-01

    In a reference frame fixed to the solar system's center of mass, a satellite's energy will change as it is deflected by a planet. But a number of satellites flying by Earth have also experienced energy changes in the Earth-centered frame -- and that's a mystery.

  12. Earth System Science Project

    Science.gov (United States)

    Rutherford, Sandra; Coffman, Margaret

    2004-01-01

    For several decades, science teachers have used bottles for classroom projects designed to teach students about biology. Bottle projects do not have to just focus on biology, however. These projects can also be used to engage students in Earth science topics. This article describes the Earth System Science Project, which was adapted and developed…

  13. Introducing Earth's Orbital Eccentricity

    Science.gov (United States)

    Oostra, Benjamin

    2015-01-01

    Most students know that planetary orbits, including Earth's, are elliptical; that is Kepler's first law, and it is found in many science textbooks. But quite a few are mistaken about the details, thinking that the orbit is very eccentric, or that this effect is somehow responsible for the seasons. In fact, the Earth's orbital eccentricity is…

  14. Wii Balance Board: Reliability and Clinical Use in Assessment of Balance in Healthy Elderly Women.

    Science.gov (United States)

    Monteiro-Junior, Renato Sobral; Ferreira, Arthur Sá; Puell, Vivian Neiva; Lattari, Eduardo; Machado, Sérgio; Otero Vaghetti, César Augusto; da Silva, Elirez Bezerra

    2015-01-01

    Force plate is considered gold standard tool to assess body balance. However the Wii Balance Board (WBB) platform is a trustworthy equipment to assess stabilometric components in young people. Thus, we aim to examine the reliability of measures of center of pressure with WBB in healthy elderly women. Twenty one healthy and physically active women were enrolled in the study (age: 64 ± 7 years; body mass index: 29 ± 5 kg/m2. The WBB was used to assess the center of pressure measures in the individuals. Pressure was linearly applied to different points to test the platform precision. Three assessments were performed, with two of them being held on the same day at a 5- to 10-minute interval, and the third one was performed 48 h later. A linear regression analysis was used to find out linearity, while the intraclass correlation coefficient was used to assess reliability. The platform precision was adequate (R2 = 0.997, P = 0.01). Center of pressure measures showed an excellent reliability (all intraclass correlation coefficient values were > 0.90; p < 0.01). The WBB is a precise and reliable tool of body stability quantitative measure in healthy active elderly women and its use should be encouraged in clinical settings. PMID:26556091

  15. Solid Earth: Introduction

    Science.gov (United States)

    Rummel, R.

    1991-10-01

    The principles of the solid Earth program are introduced. When considering the study of solid Earth from space, satellites are used as beacons, inertial references, free fall probes and carrying platforms. The phenomenon measured by these satellites and the processes which can be studied as a result of these measurements are tabulated. The NASA solid Earth program focusses on research into surface kinematics, Earth rotation, land, ice, and ocean monitoring. The ESA solid Earth program identifies as its priority the Aristoteles mission for determining the gravity and magnetic field globally, with high spatial resolution and high accuracy. The Aristoteles mission characteristics and goals are listed. The benefits of the improved gravity information that will be provided by this mission are highlighted. This information will help in the following research: geodesy, orbit mechanics, geodynamics, oceanography, climate sea level, and the atmosphere.

  16. Earth Science Informatics - Overview

    Science.gov (United States)

    Ramapriyan, H. K.

    2015-01-01

    Over the last 10-15 years, significant advances have been made in information management, there are an increasing number of individuals entering the field of information management as it applies to Geoscience and Remote Sensing data, and the field of informatics has come to its own. Informatics is the science and technology of applying computers and computational methods to the systematic analysis, management, interchange, and representation of science data, information, and knowledge. Informatics also includes the use of computers and computational methods to support decision making and applications. Earth Science Informatics (ESI, a.k.a. geoinformatics) is the application of informatics in the Earth science domain. ESI is a rapidly developing discipline integrating computer science, information science, and Earth science. Major national and international research and infrastructure projects in ESI have been carried out or are on-going. Notable among these are: the Global Earth Observation System of Systems (GEOSS), the European Commissions INSPIRE, the U.S. NSDI and Geospatial One-Stop, the NASA EOSDIS, and the NSF DataONE, EarthCube and Cyberinfrastructure for Geoinformatics. More than 18 departments and agencies in the U.S. federal government have been active in Earth science informatics. All major space agencies in the world, have been involved in ESI research and application activities. In the United States, the Federation of Earth Science Information Partners (ESIP), whose membership includes nearly 150 organizations (government, academic and commercial) dedicated to managing, delivering and applying Earth science data, has been working on many ESI topics since 1998. The Committee on Earth Observation Satellites (CEOS)s Working Group on Information Systems and Services (WGISS) has been actively coordinating the ESI activities among the space agencies. Remote Sensing; Earth Science Informatics, Data Systems; Data Services; Metadata

  17. Psychology of the nuclear balance

    Energy Technology Data Exchange (ETDEWEB)

    Sonntag, P.

    1981-10-01

    The balance of military forces is meant to prevent war. But it is a very precarious balance, which becomes all the more dubious when the deterrent is no longer psychologically effective: when the country attacked is deterred from striking back with nuclear weapons. A unilateral disarmament above the overkill level would be possible without endangering the balance. It would improve the climate for mutual disarmament.

  18. Rotor balancing apparatus and system

    Science.gov (United States)

    Lyman, Frank (Inventor); Lyman, Joseph (Inventor)

    1976-01-01

    Rotor balancing apparatus and a system comprising balance probes for measuring unbalance at the ends of a magnetically suspended rotor are disclosed. Each balance probe comprises a photocell which is located in relationship to the magnetically suspended rotor such that unbalance of the rotor changes the amount of light recorded by each photocell. The signal from each photocell is electrically amplified and displayed by a suitable device, such as an oscilloscope.

  19. Dynamic load balancing of applications

    Science.gov (United States)

    Wheat, Stephen R. (Albuquerque, NM)

    1997-01-01

    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.

  20. Radar channel balancing with commutation

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-02-01

    When multiple channels are employed in a pulse-Doppler radar, achieving and maintaining balance between the channels is problematic. In some circumstances the channels may be commutated to achieve adequate balance. Commutation is the switching, trading, toggling, or multiplexing of the channels between signal paths. Commutation allows modulating the imbalance energy away from the balanced energy in Doppler, where it can be mitigated with filtering.

  1. Energy Balance Models and Planetary Dynamics

    Science.gov (United States)

    Domagal-Goldman, Shawn

    2012-01-01

    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.

  2. Functional MR imaging of a simulated balance task.

    Science.gov (United States)

    Karim, Helmet T; Sparto, Patrick J; Aizenstein, Howard J; Furman, Joseph M; Huppert, Theodore J; Erickson, Kirk I; Loughlin, Patrick J

    2014-03-25

    Human postural control, which relies on information from vestibular, visual, and proprioceptive inputs, degrades with aging, and falls are the leading cause of injury in older adults. In the last decade, functional neuroimaging studies have been performed in order to gain a greater understanding of the supraspinal control of balance and walking. It is known that active balancing involves cortical and subcortical structures in the brain, but neuroimaging of the brain during these tasks has been limited. The study of the effect of aging on the functional neuroimaging of posture and gait has only recently been undertaken. In this study, an MRI-compatible force platform was developed to simulate active balance control. Eleven healthy participants (mean age 75±5 yr) performed an active balance simulation task by using visual feedback to control anterior-posterior center of pressure movements generated by ankle dorsiflexor (DF) and plantarflexor (PF) movements, in a pattern consistent with upright stance control. An additional ankle DF/PF exertion task was performed. During both the active balance simulation and the ankle DF/PF tasks, the bilateral fusiform gyrus and middle temporal gyrus, right inferior, middle, and superior frontal gyrii were activated. No areas were found to be more active during the ankle DF/PF task when compared with the active balance simulation task. When compared to the ankle DF/PF task, the active balance simulation task elicited greater activation in the middle and superior temporal gyrii, insula, and a large cluster that covered the corpus callosum, superior and medial frontal gyrii, as well as the anterior cingulate and caudate nucleus. This study demonstrates the utility in using a force platform to simulate active balance control during MR imaging that elicits activity in cortical regions consistent with studies of active balance and mental imagery of balance. PMID:24480476

  3. Validity and reliability of the Nintendo Wii Balance Board for assessment of standing balance.

    Science.gov (United States)

    Clark, Ross A; Bryant, Adam L; Pua, Yonghao; McCrory, Paul; Bennell, Kim; Hunt, Michael

    2010-03-01

    Impaired standing balance has a detrimental effect on a person's functional ability and increases their risk of falling. There is currently no validated system which can precisely quantify center of pressure (COP), an important component of standing balance, while being inexpensive, portable and widely available. The Wii Balance Board (WBB) fits these criteria, and we examined its validity in comparison with the 'gold standard'-a laboratory-grade force platform (FP). Thirty subjects without lower limb pathology performed a combination of single and double leg standing balance tests with eyes open or closed on two separate occasions. Data from the WBB were acquired using a laptop computer. The test-retest reliability for COP path length for each of the testing devices, including a comparison of the WBB and FP data, was examined using intraclass correlation coefficients (ICC), Bland-Altman plots (BAP) and minimum detectable change (MDC). Both devices exhibited good to excellent COP path length test-retest reliability within-device (ICC=0.66-0.94) and between-device (ICC=0.77-0.89) on all testing protocols. Examination of the BAP revealed no relationship between the difference and the mean in any test, however the MDC values for the WBB did exceed those of the FP in three of the four tests. These findings suggest that the WBB is a valid tool for assessing standing balance. Given that the WBB is portable, widely available and a fraction of the cost of a FP, it could provide the average clinician with a standing balance assessment tool suitable for the clinical setting. PMID:20005112

  4. 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

  5. Pressure transmitter

    International Nuclear Information System (INIS)

    An isolator or the like for nuclear power stations employed to separate two fluids or two pressures or other sensing instruments from the containment or elsewhere includes first and second fluid filled bellows having a fluid connection in between and which together provide a pressure transfer mechanism. Excessive travel of the bellows is prevented by overrange valves, one of which closes the pathway on application of high pressure. (author)

  6. Transport phenomena in the Earth's plasma sheet

    Science.gov (United States)

    Angelopoulos, Vassilis

    1993-01-01

    We present a series of studies that utilize observation and modeling in order to characterize transport in the earth's plasma sheet out to distances of 23 R(sub E). After a brief description of the dissertation's goals in Chapter 1, we analyze in Chapter 2 representative cases of high speed flows in the inner central plasma sheet along with the concurrent behavior of the plasma and magnetic field. We argue that such flows are organized in 10 min. time scale entities of convection enhancements that we term bursty bulk flow (BBF) events. BBF's have a substructure that is on a 1 min time scale, referred to as 'flow bursts'. BBF's represent intervals of enhanced, predominantly earthward transport of mass energy and magnetic flux. In Chapter 3, we use an algorithm to automatically detect BBF's and study their statistical properties. BBF's cause the plasma sheet to be in a more dipolarized, higher temperature state for a long time after their subsidence. Despite their short duration, BBF's can account for most of the measured earthward transport of particles, energy, and magnetic flux in the plasma sheet. The concept of BBF's as a particular state of transport in the plasma sheet is applied in Chapter 4 to the study of the non-BBF, quiet state of the inner plasma sheet. We construct the average ion velocity pattern in the quiet inner plasma sheet. We show that a semi-empirical magnetic field model of the magnetotail along with the inferred cross tail electric field and the measured average density reproduce the observed velocity averages assuming that the flow is the sum of corrotation, an E x B flow, and a model-derired diamagnetic drift Despite the qualitative agreement of the average flow pattern with our model calculations, the flow exhibits variability much larger than its average. The non-BBF flow is highly irregular and fundamentally unsteady, a reason why convection in the quiet state of the plasma sheet may be able to avoid a pressure balance inconsistency with the lobes. Chapter 5 explores whether a segregation of plasma sheet states similar to the one applied to the inner plasma sheet can also be extended to the outer plasma sheet.

  7. People, poverty and the Earth Summit.

    Science.gov (United States)

    Wheeler, J

    1992-01-01

    UNCED is about human beings managing their affairs so that all can achieve a reasonably good life without destroying the life-supporting environment. Currently human activities are approaching an upset of environmental balance through production of greenhouse gases, depletion of the ozone layer, and reduction of natural resources. Equity is the right to a decent life for the current human population of 5.5 billion and the future 10 billion expected within the next 50 years. A minimum use of environmental space/person is required. The Earth Summit will be a broad statement of environmental policy. Agenda 21 includes 115 action programs within 40 chapters. Separate conventions will be held on climate and biodiversity. The secretariat of UNCED has been working primarily with Agenda 21. Population issues are emphasized in Chapter 5 ("Demographic Dynamics and Sustainability") of the first section in Agenda 21 on Social and Economic Dimensions. The program areas include 1) research on the links between population, the environment, and development; 2) formulation by governments of integrated national policies on environment and development, which account for demographic trends, and promotion of population literacy; and 3) implementation of local level programs to ensure access to education and information and services in order to plan families freely and responsibly. Increases in funding for the population program are anticipated to be US $9 billion by the year 2000 and about US $7 billion/year until then. The year 2000 will bring with it a doubling of urban population in developing countries. There are challenges and opportunities to expand private sector job creation, education, clean water, and family health services. In addition to managing human settlements, there is also management of fragile ecosystems, which means relieving the pressure on these lands through urban migration or relocation to richer agricultural areas. The goal for agriculture is to triple food outputs over the next 50 years without increasing land use; improved soil and management systems are needed. Ocean/seas protection from pollution and provision of an adequate, clean water supply are other challenges. Demographic transition must be completed in order to improve global development success. PMID:12317386

  8. 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)

  9. Improving Balance Function Using Low Levels of Electrical Stimulation of the Balance Organs

    Science.gov (United States)

    Bloomberg, Jacob; Reschke, Millard; Mulavara, Ajitkumar; Wood, Scott; Serrador, Jorge; Fiedler, Matthew; Kofman, Igor; Peters, Brian T.; Cohen, Helen

    2012-01-01

    Crewmembers returning from long-duration space flight face significant challenges due to the microgravity-induced inappropriate adaptations in balance/sensorimotor function. The Neuroscience Laboratory at JSC is developing a method based on stochastic resonance to enhance the brain's ability to detect signals from the balance organs of the inner ear and use them for rapid improvement in balance skill, especially when combined with balance training exercises. This method involves a stimulus delivery system that is wearable/portable and provides imperceptible electrical stimulation to the balance organs of the human body. Stochastic resonance (SR) is a phenomenon whereby the response of a nonlinear system to a weak periodic input signal is optimized by the presence of a particular non-zero level of noise. This phenomenon of SR is based on the concept of maximizing the flow of information through a system by a non-zero level of noise. Application of imperceptible SR noise coupled with sensory input in humans has been shown to improve motor, cardiovascular, visual, hearing, and balance functions. SR increases contrast sensitivity and luminance detection; lowers the absolute threshold for tone detection in normal hearing individuals; improves homeostatic function in the human blood pressure regulatory system; improves noise-enhanced muscle spindle function; and improves detection of weak tactile stimuli using mechanical or electrical stimulation. SR noise has been shown to improve postural control when applied as mechanical noise to the soles of the feet, or when applied as electrical noise at the knee and to the back muscles. SR using imperceptible stochastic electrical stimulation of the vestibular system (stochastic vestibular stimulation, SVS) applied to normal subjects has shown to improve the degree of association between the weak input periodic signals introduced via venous blood pressure receptors and the heart-rate responses. Also, application of SVS over 24 hours improves the long-term heart-rate dynamics and motor responsiveness as indicated by daytime trunk activity measurements in patients with multi-system atrophy, Parkinson s disease, or both, including patients who were unresponsive to standard therapy for Parkinson s disease. Recent studies conducted at the NASA JSC Neurosciences Laboratories showed that imperceptible SVS, when applied to normal young healthy subjects, leads to significantly improved balance performance during postural disturbances on unstable compliant surfaces. These studies have shown the benefit of SR noise characteristic optimization with imperceptible SVS in the frequency range of 0-30 Hz, and amplitudes of stimulation have ranged from 100 to 400 microamperes.

  10. Accretion of the Earth.

    Science.gov (United States)

    Canup, Robin M

    2008-11-28

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

  11. Earths, Super-Earths, and Jupiters

    Science.gov (United States)

    Chiang, Eugene; Lee, Eve J.

    2015-12-01

    We review and add to the theory of how planets acquire atmospheres from parent circumstellar disks. We derive (in real time) a simple and general analytic expression for how a planet's atmosphere grows with time, as a function of the underlying core mass and nebular conditions, including the gas metallicity. Planets accrete as much gas as can cool: an atmosphere's doubling time is given by its Kelvin-Helmholtz time. The theory can be applied in any number of settings --- gas-rich vs. gas-poor nebulae; dusty vs. dust-free atmospheres; close-in vs. far-out distances --- and is confirmed against detailed numerical models for objects ranging in mass from Mars (0.1 Mearth) to the most extreme super Earths (10--20 Mearth). We explain why heating from planetesimal accretion, commonly invoked in models of core accretion, is irrelevant. This talk sets the stage for another presentation, "Breeding Super-Earths and Birthing Super-Puffs".

  12. Future Satellite Gravimetry and Earth Dynamics

    CERN Document Server

    Flury, Jakob

    2005-01-01

    Currently, a first generation of dedicated satellite missions for the precise mapping of the Earth’s gravity field is in orbit (CHAMP, GRACE, and soon GOCE). The gravity data from these satellite missions provide us with very new information on the dynamics of planet Earth. In particular, on the mass distribution in the Earth’s interior, the entire water cycle (ocean circulation, ice mass balance, continental water masses, and atmosphere), and on changes in the mass distribution. The results are fascinating, but still rough with respect to spatial and temporal resolution. Technical progress in satellite-to-satellite tracking and in gravity gradiometry will allow more detailed results in the future. In this special issue, Earth scientists develop visions of future applications based on follow-on high-precision satellite gravimetry missions.

  13. Laser techniques in high-pressure geophysics

    Science.gov (United States)

    Hemley, R. J.; Bell, P. M.; Mao, H. K.

    1987-01-01

    Laser techniques in conjunction with the diamond-anvil cell can be used to study high-pressure properties of materials important to a wide range of problems in earth and planetary science. Spontaneous Raman scattering of crystalline and amorphous solids at high pressure demonstrates that dramatic changes in structure and bonding occur on compression. High-pressure Brillouin scattering is sensitive to the pressure variations of single-crystal elastic moduli and acoustic velocities. Laser heating techniques with the diamond-anvil cell can be used to study phase transitions, including melting, under deep-earth conditions. Finally, laser-induced ruby fluorescence has been essential for the development of techniques for generating the maximum pressures now possible with the diamond-anvil cell, and currently provides a calibrated in situ measure of pressure well above 100 gigapascals.

  14. Energetics and dynamics of the earth's thermosphere

    International Nuclear Information System (INIS)

    An overview of current (1983-1986) research on the energetics and dynamics of the earth's thermosphere is presented. The global mean radiative and thermal balance in the thermosphere is examined, and the results of experimental investigations for the low-latitude, mid-latitude, and high-latitude upper thermosphere regions are discussed. Consideration is also given to research done in the lower thermosphere, including investigations of tidal and gravity wave processes. In addition, various thermospheric models are discussed together with the results obtained by the analysis of the thermosphere's energetics and dynamics

  15. 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

  16. The right balance

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    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...

  17. Paul Collier : Balancing beams

    CERN Multimedia

    2009-01-01

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

  18. Balancing "we" and "me".

    Science.gov (United States)

    Congdon, Christine; Flynn, Donna; Redman, Melanie

    2014-10-01

    The open office is the dominant form of workspace design for good reason: It fosters collaboration, promotes learning, and nurtures strong culture. But what most companies fail to realize is that collaboration has a natural rhythm that requires both interaction and private contemplation. Companies have been trying for decades to find the balance between public and private workspace that best supports collaboration. In 1980 52% of U.S. employees lacked workspaces where they could concentrate without distraction. In response, high-walled cubicles took over the corporate landscape. By the late 1990s, the tide had turned, and only 23% of employees wanted more privacy, and 50% wanted more access to other people. Ever since, firms have been beefing up spaces that support collaboration and shrinking areas for individual work. But the pendulum seems to have swung too far: Once again, people feel a pressing need for privacy, not only to do heads-down work but to cope with the intensity of work today. To address these needs, according to the authors, we have to rethink our assumptions about privacy. Traditionally defined in physical terms, privacy is now about the individual's ability to control information and stimulation. In this article, the authors examine workspace design through the new lens of privacy and offer insights on how to foster teamwork and solitude. PMID:25509575

  19. 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.)

  20. Distributed Selfish Load Balancing

    CERN Document Server

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

    2005-01-01

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

  1. Project Earth Science

    CERN Document Server

    Holt, Geoff

    2011-01-01

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

  2. Earth's background free oscillations

    Science.gov (United States)

    Suda; Nawa; Fukao

    1998-03-27

    Earth's free oscillations were considered to be transient phenomena occurring after large earthquakes. An analysis of records of the IDA (International Deployment of Accelerometers) gravimeter network shows that Earth is freely oscillating at an observable level even in seismically inactive periods. The observed oscillations are the fundamental spheroidal modes at frequencies between 2 and 7 millihertz. Numerical modeling indicates that these incessant excitations cannot be explained by stacked effects of a large number of small earthquakes. The observed "background" free oscillations represent some unknown dynamic process of Earth. PMID:9516105

  3. Wringing out the earth

    Science.gov (United States)

    van Loon, A. J.

    2000-03-01

    The increase in global energy consumption urges the exploitation of known energy resources in the most efficient way. The oil and gas industry seems well capable, but politics may hamper optimum recovery, even though politicians advocate that the laws and regulations laid upon the industry are meant to promote a sustainable society and to diminish environmental pollution. Lack of geological insight sometimes plays a role, which implies that an attitude of effectively wringing out the Earth is not sufficient: more attention for earth-scientific education may turn out to be even more important. This does not affect, however, the need for ever more effective technologies for wringing out the Earth.

  4. The Earth's Magnetic Interior

    CERN Document Server

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

    2011-01-01

    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

  5. High-pressure optical studies

    International Nuclear Information System (INIS)

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

  6. A contribution to the validation of the Wii Balance Board for the assessment of standing balance.

    Science.gov (United States)

    Pavan, Piero; Cardaioli, Matteo; Ferri, Ilaria; Gobbi, Erica; Carraro, Attilio

    2015-10-01

    Valid and reliable accessible measures of balance are required in a health-related fitness test battery, both in the general population and in groups with special needs. For this purpose, the capability of the Wii Balance Board (WBB) in evaluating standing balance was analysed and compared with a laboratory-graded force platform (FP). A 30-s double limb standing test with open and closed eyes was performed by 28 individuals (12 male and 16 female, mean age = 23.8, SD = 2.7 years). A simple method of acquisition of the centre of pressure (CoP) over time was applied to compare WBB and FP simultaneously on the same signal. User-defined software was developed to obtain the CoP from WBB over time and the resulting related measures and graphical representations. The comparison of measures, such as sway path and maximum oscillations along the anterior-posterior and medial-lateral direction, obtained with the FP and the WBB shows that the latter, in conjunction with the user-defined developed software, can be appropriate, considering prescribed limits, and an easy-to-use tool for evaluating standing balance. PMID:25222558

  7. Monitoring Earth's Climate with Shortwave Hyperspectral Reflectance

    Science.gov (United States)

    Pilewskie, Peter

    The Sun provides nearly all the energy that fuels the dynamical, chemical, and biological processes in the Earth system. Absorbed solar radiation, the difference between incoming and reflected sunlight, defines Earth’s equilibrium temperature and, along with the emitted infrared radiation, determines the climate state of the planet. The transfer of solar radiation through the atmosphere is modulated by wavelength-specific interactions that are unique for given surface types and the intervening atmospheric gases and condensed species. Reflected radiation that exits the Earth’s atmosphere carries with it the complex fingerprint of the Earth system state. How this signal varies temporally, spatially, and spectrally is a measure of those processes within the Earth system that affect climate change. Despite its importance to the basic energy balance between Earth and the solar-terrestrial environment in which it resides, a precise record of the nature of reflected solar spectral radiation over all climate-relevant time scales remains elusive. A primary goal of a climate observing system is to obtain climate benchmark data records with sufficient accuracy for identifying climate variability on decadal time scales and longer, and with sufficient information content to attribute change to underlying causes. Until recently, detecting climate change signatures in reflected solar radiance has been hindered by instrument accuracy and stability, insufficient spectral coverage and resolution, and inherent sampling limitations from low-Earth orbit observations. This talk will discuss the challenges to monitoring the shortwave energy budget from space. I will present new studies on methods to separate the various contributions in the top-of-atmosphere outgoing shortwave radiance using existing satellite (SCIAMACHY) data and explore methods to enhance trend detection in hyperspectral reflectance time series. Finally, I look ahead to the requirements for a climate observing system for monitoring shortwave hyperspectral reflectance, the Earth Climate Hyperspectral Observatory (ECHO).

  8. A balancing act for renewables

    Science.gov (United States)

    Elliott, David

    2016-01-01

    Energy storage will play a key role in increasing the use of variable energy sources. Nonetheless, storage is not the only balancing option and the overall design of power systems will incorporate a range of flexible generation, storage and grid-balancing options of different types and scales.

  9. Balance Laws in Micromorphic Elasticity

    OpenAIRE

    Lazar, Markus; Anastassiadis, Charalampos

    2013-01-01

    We derive the Eshelby stress tensor, the angular momentum tensor and the dilatational vector flux for micromorphic elasticity. We give the corresponding balance laws and the J, L, and M integrals. Also we discuss when the balance laws become conservation laws.

  10. When Do States Balance Power?

    DEFF Research Database (Denmark)

    Hariri, Jacob Gerner; Wivel, Anders

    2010-01-01

    This paper explores the logic of balancing in structural realist theory. Arguably, the durability of the unipolar moment is a challenge to the logic of balancing. The paper uses the tools of microeconomics to build a mathematical model of structural realism. The simple model reiterates the...

  11. PREFACE: 3rd International Conference on Geological, Geographical, Aerospace and Earth Science 2015 (AeroEarth 2015)

    Science.gov (United States)

    Gaol, F. L.

    2016-02-01

    The 3rd International Conferences on Geological, Geographical, Aerospaces and Earth Sciences 2015 (AeroEarth 2015), was held at The DoubleTree Hilton, Jakarta, Indonesia during 26 - 27 September 2015. The 1st AeoroEarth was held succefully in Jakarta in 2013. The success continued to The 2nd AeroEarth 2014 that was held in Kuta Bali, Indonesia. The publications were published by EES IOP in http://iopscience.iop.org/1755-1315/19/1 and http://iopscience.iop.org/1755-1315/23/1 respectively. The AeroEarth 2015 conference aims to bring together researchers, engineers and scientists from around the world. Through research and development, Earth's scientists have the power to preserve the planet's different resource domains by providing expert opinion and information about the forces which make life possible on Earth. The theme of AeroEarth 2015 is ''Earth and Aerospace Sciences : Challenges and Opportunities'' Earth provides resources and the exact conditions to make life possible. However, with the advent of technology and industrialization, the Earth's resources are being pushed to the brink of depletion. Non-sustainable industrial practices are not only endangering the supply of the Earth's natural resources, but are also putting burden on life itself by bringing about pollution and climate change. A major role of earth science scholars is to examine the delicate balance between the Earth's resources and the growing demands of industrialization. Through research and development, earth scientists have the power to preserve the planet's different resource domains by providing expert opinion and information about the forces which make life possible on Earth. We would like to express our sincere gratitude to all in the Technical Program Committee who have reviewed the papers and developed a very interesting Conference Program as well as the invited and plenary speakers. This year, we received 78 papers and after rigorous review, 18 papers were accepted. The participants come from 8 countries. There are 4 (four) Parallel Sessions and 3 (Three) Keynote Speakers. It is an honour to present this volume of IOP Conference Series: Earth and Environmental Science (EES) and we deeply thank the authors for their enthusiastic and high-grade contribution. Finally, we would like to thank the conference chairmen, the members of the steering committee, the organizing committee, the organizing secretariat and the financial support from the conference sponsors that allowed the success of AeroEarth 2015.

  12. Hydration study of rare earth trivalent ions

    International Nuclear Information System (INIS)

    In this work we confirm the fact that in the case of rare earth ions, the hydration process has an electrostatic character. We calculate with our theoretical model the local electrostatic field which is equivalent to an electrostriction pressure. The local density around an Ln3+ ions is obtained from the state equation of pure water at high pressure. The hydration numbers obtained by this model agree with the experimental results and show a progressive diminution of one molecule of water from La3+ to Lu3+

  13. Direct measurements of sound velocities of iron with nuclear resonant inelastic x-ray scattering under high pressure and temperature

    Science.gov (United States)

    Lin, J.; Sturhahn, W.; Zhao, J.; Shen, G.; Mao, H.; Hemley, R.

    2004-05-01

    Iron is the most abundant component in the Earth's core. Understanding the physical properties of Fe under core conditions is crucial for interpreting the seismological and geomagnetic observations deep in the Earth's interior. The physical properties of Fe have been extensively studied by dynamic and static high-pressure experiments and theoretical calculations, but direct static measurements of the sound velocities of iron under high pressures and temperatures are still lacking. We have built a double-sided YLF laser heating system to study iron with nuclear resonant inelastic x-ray scattering technique under simultaneously high pressures and high temperatures. Sound velocities of iron have been directly measured up to 58 GPa and 1700 K in a laser-heated diamond cell. The ''detailed balance'' principle applied to the inelastic X-ray scattering spectra provides absolute temperatures of the laser-heated sample. These temperatures are in very good agreement with values determined from the thermal radiation spectra fitted to the Planck radiation function. This independent temperature measurement of the laser-heated sample confirms the validity of temperatures determined from Planck radiation law in the laser-heated diamond anvil cell experiments. We found that temperature has a strong effect on the sound velocities; the compressional (VP) and shear wave velocities (VS) of hcp-Fe decrease significantly with increasing temperature under high pressures. VP and VS are only linearly related to the density for a given, constant temperature, while the bulk sound velocity (Vφ ) follows Birch's law, i.e., Vφ is linearly related to the density and mean atomic weight. The linear sound velocity-density line should be corrected to lower velocities in extrapolations to inner core conditions. Our results have important implications for understanding the sound velocities of the Earth's inner core as well as the fundamental physical properties of iron under extreme pressures and temperatures.

  14. Study of the atmospheric pressure loading signal in VLBI observations

    OpenAIRE

    Petrov, Leonid; Boy, Jean-Paul

    2003-01-01

    Redistribution of air masses due to atmospheric circulation causes loading deformation of the Earth's crust which can be as large as 20 mm for the vertical component and 3 mm for horizontal components. Rigorous computation of site displacements caused by pressure loading requires knowledge of the surface pressure field over the entire Earth surface. A procedure for computing 3-D displacements of geodetic sites of interest using a 6-hourly pressure field from the NCEP numerical weather models ...

  15. Whole-Earth Decompression Dynamics

    OpenAIRE

    Herndon, J. Marvin

    2005-01-01

    The principles of Whole-Earth Decompression Dynamics are disclosed leading to a new way to interpret whole-Earth dynamics. Whole-Earth Decompression Dynamics incorporates elements of and unifies the two seemingly divergent dominant theories of continential displacement, plate tectonics theory and Earth expansion theory. Whole-Earth decompression is the consequence of Earth formation from within a Jupiter-like protoplanet with subsequent loss of gases and ices and concomitant rebounding. The i...

  16. Data needs for nutrient balances

    DEFF Research Database (Denmark)

    Vinther, Finn Pilgaard

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

  17. A question of balance: Kinetic balance for electrons and positrons

    International Nuclear Information System (INIS)

    Graphical abstract: Kinetic balance for both electrons and positrons is achieved by applying the correct relation for positive and negative energy states separately and then using the electron and positron eigensolutions from the separate diagonalizations of the Hamiltonian as a dual basis. Highlights: ► Kinetic balance for electrons and positrons is achieved in a dual atomic basis. ► Dual atomic balance alleviates, but does not eliminate, energy prolapse. ► Positron affinities converge quicker with basis set size with dual atomic balance. - Abstract: The kinetic balance criterion used in current relativistic basis set codes is satisfied by the electron solutions of the Dirac equation, but not the positron solutions. A proposal for applying kinetic balance to both sets of solutions is presented. The method is applied along with “normal” kinetic balance to one-electron systems, to investigate its possible relation to prolapse, and to the positron affinity of F−, to investigate the kinetic energy deficiency for positron solutions. The new method reduces but does not eliminate prolapse for energy-optimized basis sets, and provides faster and smoother convergence with basis set size for the positron affinity.

  18. Gambling with the earth

    CERN Multimedia

    Muir, H

    2000-01-01

    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).

  19. Earth Science Programs

    Science.gov (United States)

    Freeman, Tony; Im, Eastwood

    2007-01-01

    This slide presentation reviews the JPL missions that enabling Earth Sciences, past, present and future. Included is a list of the National Academy of Sciences Space Studies Board of the recommended missions that are of interest to JPL.

  20. Earth Sciences Today

    International Nuclear Information System (INIS)

    This book intents to present a sample of some aspects of the Earth sciences that are studied at the moment in Mexico. In the context of the International research. The first chapter describes some of the aspects of seismology, considering the study of natural and artificial seismic waves. The more important applications in Mexico are also discussed. The risk associated with the earthquakes and the structures that govern the transmission of seismic signals. In later chapters other signs of the internal dynamic of Earth and other planets are described, such as volcanism, which allow a comparative analysis. This discussions are complemented with three chapters that synthesize aspects of the internal composition of the Earth and the nature and consequences of the magnetic field fluctuations. In the last chapters, the Earth sciences are related with the ecology, by means of the study of that one fragile layer, the soil. (Author)

  1. Earth study from space

    Science.gov (United States)

    Sidorenko, A. V.

    1981-01-01

    The significance that space studies are making to all Earth sciences in the areas of geography, geodesy, cartography, geology, meteorology, oceanology, agronomy, and ecology is discussed. It is predicted that cosmonautics will result in a revolution in science and technology.

  2. Down to earth relativity

    Science.gov (United States)

    Shapiro, I. I.

    1978-01-01

    The basic concepts of the special and general theories of relativity are described. Simple examples are given to illustrate the effect of relativity on measurements of time and frequency in the near-earth environment.

  3. Earth rotation and geodynamics

    Science.gov (United States)

    Bogusz, Janusz; Brzezinski, Aleksander; Kosek, Wieslaw; Nastula, Jolanta

    2015-12-01

    This paper presents the summary of research activities carried out in Poland in 2011-2014 in the field of Earth rotation and geodynamics by several Polish research institutions. It contains a summary of works on Earth rotation, including evaluation and prediction of its parameters and analysis of the related excitation data as well as research on associated geodynamic phenomena such as geocentre motion, global sea level change and hydrological processes. The second part of the paper deals with monitoring of geodynamic phenomena. It contains analysis of geodynamic networks of local, and regional scale using space (GNSS and SLR) techniques, Earth tides monitoring with gravimeters and water-tube hydrostatic clinometer, and the determination of secular variation of the Earth' magnetic field.

  4. Jupiter and planet Earth

    International Nuclear Information System (INIS)

    The evolution of Jupiter and Earth are discussed along with their atmospheres, the radiation belts around both planets, natural satellites, the evolution of life, and the Pioneer 10. Educational study projects are also included

  5. Diversity of burial rates in convergent settings decreased as Earth aged.

    Science.gov (United States)

    Nicoli, Gautier; Moyen, Jean-François; Stevens, Gary

    2016-01-01

    The evolution and the growth of the continental crust is inextricably linked to the evolution of Earth's geodynamic processes. The detrital zircon record within the continental crust, as well as the isotopic composition of this crust, indicates that the amount of juvenile felsic material decreased with time and that in geologically recent times, the generation of new crust is balanced by recycling of the crust back into the mantle within subduction zones. However it cannot always have been so; yet the nature of the crust and the processes of crustal reworking in the Precambrian Earth are not well constrained. Here we use both detrital zircon ages and metamorphic pressure-temperature-time (P-T-t) information from metasedimentary units deposited in proposed convergent settings from Archaean, Proterozoic and Phanerozoic terrains to characterize the evolution of minimum estimates of burial rate (km.Ma(-1)) as a function of the age of the rocks. The demonstrated decrease in burial rate correlates positively with a progressive decrease in the production of juvenile felsic crust in the Archaean and Proterozoic. Burial rates are also more diverse in the Archaean than in modern times. We interpret these features to reflect a progressive decrease in the diversity of tectonic processes from Archaean to present, coupled with the emergence of the uniquely Phanerozoic modern-style collision. PMID:27216133

  6. Investigation of hot Flow Anomaly structure observed near the Earth's bow shock

    Science.gov (United States)

    Shestakov, A. Yu.; Vaisberg, O. L.

    2012-02-01

    The work is dedicated to investigation of Hot Flow Anomaly (HFA), formed at the front of Earth's bows hock. Using Interball-Tail data we estimated orientation of the current sheet that was a cause of the anomaly. From the ion energy-time spectrogram we divided the anomaly into several regions. The motional electric fields near the HFA were estimated with 3D model of Earth's bow shock. In accordance with previous investigations of HFA's formation conditions these fields were directed towards the current sheet on both sides of it. We also provided the picture of HFA's motion along the bow shock and calculated its speed. Analyzing ions' bulk velocities within the HFA we found that the anomaly is expanding. This conclusion was supported by estimation of thermal and magnetic pressure balance. Ion energy-time spectrogram shows that anomaly is a complicated structure consisting of two partsleading and trailing. Comparison of ion velocity distributions, magnetic field data and ion energy-time spectrogram provides better understanding of the phenomena and indicated the region that is the source of thermal and convective energy inside HFA.

  7. Earth's surface heat flux

    OpenAIRE

    Davies, J. H.; Davies, D.R.

    2010-01-01

    We present a revised estimate of Earth's surface heat flux that is based upon a heat flow data-set with 38 347 measurements, which is 55% more than used in previous estimates. Our methodology, like others, accounts for hydrothermal circulation in young oceanic crust by utilising a half-space cooling approximation. For the rest of Earth's surface, we estimate the average heat flow for different geologic domains as defined by global digital geology maps; and then produce the global estimate by ...

  8. Earth's surface heat flux

    OpenAIRE

    Davies, J. H.; Davies, D.R.

    2009-01-01

    We present a revised estimate of Earth's surface heat flux that is based upon a heat flow data-set with 38 347 measurements, which is 55% more than used in previous estimates. Our methodology, like others, accounts for hydrothermal circulation in young oceanic crust by utilising a half-space cooling approximation. For the rest of Earth's surface, we estimate the average heat flow for different geologic domains as defined by global digital geology maps; and then produce the global estimate by ...

  9. Life After Earth

    OpenAIRE

    Marzban, Caren; Viswanathan, Raju; Yurtsever, Ulvi

    2013-01-01

    A recent study reported that there is evidence life may have originated prior to the formation of the Earth. That conclusion was based on a regression analysis of a certain data set involving evolution of functional genome size across major phyla. Here it is shown that if measurement errors and "confidence" intervals are taken into account, then the regression analysis of the same data set leads to conclusions that allow for life to have appeared after the formation of the Earth.

  10. Earth rotation and geodynamics

    OpenAIRE

    Bogusz Janusz; Brzezinski Aleksander; Kosek Wieslaw; Nastula Jolanta

    2015-01-01

    This paper presents the summary of research activities carried out in Poland in 2011-2014 in the field of Earth rotation and geodynamics by several Polish research institutions. It contains a summary of works on Earth rotation, including evaluation and prediction of its parameters and analysis of the related excitation data as well as research on associated geodynamic phenomena such as geocentre motion, global sea level change and hydrological processes. The second part of the paper deals wit...

  11. Gravity and expanding Earth

    OpenAIRE

    Scalera, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia

    2003-01-01

    The analysis of different clues indicating a variation of the local gravity (g) through geological time is performed. The examined data come from Astrogeodesy (PM and TPW), Paleogeography, Tidal torques, J2 variation, and paleogravity data from Geology. It is shown that a joint reasoning about all these data can constrain the possible variation rate of G, g and M (Earths mass). The result is that, albeit in the past great theoretical and experimental efforts were made in propo...

  12. EARTH ROADS ARE EASY

    OpenAIRE

    David O. Whitten

    2000-01-01

    The earliest European immigrants in America traveled on waterways and on pathways worn into the earth by animals and Native Americans. Once their communities began to thrive, settlers widened paths and cleared new roads and streets then began experimenting with inexpensive surfacing to reduce dust in dry weather and mud in wet. Earth Roads Are Easy investigates materials and techniques used to maintain primitive thoroughfares with a minimum of effort and expense. The options range from the ...

  13. Fuller's earth (montmorillonite) pneumoconiosis.

    OpenAIRE

    Gibbs, A R; Pooley, F.D.

    1994-01-01

    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.

  14. Mathematics of Planet Earth

    OpenAIRE

    Željka Tutek

    2013-01-01

    At the beginning of the December 2013, it was announced that the successful year-long world-wide project Mathematics of Planet Earth 2013 (MPE2013) under the patronage of UNESCO will continue as Mathematics of Planet Earth (MPE)! The idea of Christiane Rousseau, the past president of the Canadian Mathematical Society, about uniting the world’s mathematicians in an effort to bring awareness to global issues has been worked out far beyond what she could have hoped.

  15. Earth construction: bird teaching

    OpenAIRE

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

    2009-01-01

    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...

  16. Energy Budget: Earth's Most Important and Least Appreciated Planetary Attribute

    Science.gov (United States)

    Chambers, Lin; Bethea, Katie

    2013-01-01

    The energy budget involves more than one kind of energy. People can sense this energy in different ways, depending on what type of energy it is. We see visible light using our eyes. We feel infrared energy using our skin (such as around a campfire). We know some species of animals can see ultraviolet light and portions of the infrared spectrum. NASA satellites use instruments that can "see" different parts of the electromagnetic spectrum to observe various processes in the Earth system, including the energy budget. The Sun is a very hot ball of plasma emitting large amounts of energy. By the time it reaches Earth, this energy amounts to about 340 Watts for every square meter of Earth on average. That's almost 6 60-Watt light bulbs for every square meter of Earth! With all of that energy shining down on the Earth, how does our planet maintain a comfortable balance that allows a complex ecosystem, including humans, to thrive? The key thing to remember is the Sun - hot though it is - is a tiny part of Earth's environment. Earth's energy budget is a critical but little understood aspect of our planetary home. NASA is actively studying this important Earth system feature, and sharing data and knowledge about it with the education community.

  17. Simulations of micrometeoroid interactions with the Earth atmosphere

    CERN Document Server

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

    2013-01-01

    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...

  18. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    McComas, D.J.

    1986-09-01

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

  20. Pre-onset Azimuthal Pressure Gradient and Associated Auroral Intensifications Related to Dipolarization Fronts

    Science.gov (United States)

    Xing, X.; Lyons, L. R.; Angelopoulos, V.; Zhou, X.; Donovan, E.; Larson, D. E.; Carlson, C. W.; Auster, U.

    2011-12-01

    The plasma pressure spatial distribution and the magnetic field in force balance with it determine the distribution of the Field-Aligned Current (FAC) in the quasi-static near-Earth plasma sheet. The time evolution of the azimuthal plasma pressure gradient during undisturbed periods is of particular importance in leading to the evolution of FACs, which strongly affect the ionospheric current circulation and the aurora formation before dynamical processes strike, e.g., substorms. Xing et al. (2011) demonstrated by case study that the plasma sheet pressure gradient at ~11 RE near the substorm onset meridian undergoes a substantial duskward enhancement shortly before the onset as identified from the auroral poleward expansion. The increased upward FAC driven by this pressure gradient enhancement leads to the thin onset arc intensification from which the poleward expansion initiates. The mechanism of the formation of such a transient duskward pressure gradient is still an open question. In the present study, we employ the multi-THEMIS spacecraft in azimuthal conjunction -at ~-11 RE and examine the ion flux and distributions during the period of pressure gradient enhancement. Strong field-aligned ion flux enhancements covering the energy range from several KeV to above 25KeV were observed by the spacecraft identifying the higher pressure increase, while at the same time the ion distributions show substantial field-aligned, mushroom-like shift in velocity space. These resemble the ion acceleration ahead of earthward moving dipolarization fronts in a highly stretched magnetic field during the late growth phase. The local plasma develops strong transient parallel anisotropy due to the ion acceleration. On the other hand, the spacecraft observing the lower pressure increase found weaker or no ion flux enhancements and had nearly isotropic distributions. Due to these spatial differences, similar transient pressure gradient enhancements in the dawnward direction were also found for some events. These suggest that the transient azimuthal pressure gradient enhancement near the onset meridian could result from the azimuthal difference of the ion acceleration caused by the localized dipolarization fronts that reach the near-Earth plasma sheet at the onset meridian. The associated transient upward FAC enhancement, which leads to the thin onset arc intensification, would thus be related to the current pair generated in the plasma compression region ahead of the dipolarization front. Thus the earthward penetrating plasma flow channels could play a dominant role in leading to substorm onset.

  1. Pressure transducers

    International Nuclear Information System (INIS)

    Strain gauges pressure transducers types are presented. Models, characteristics and calibration procedures were also analysed. Initially, a theoretical study was accomplished to evaluate metallic alloys behavior on sensing elements manufacturing, and diaphragm was used as deflecting elements. Electrical models for potenciometric transducers were proposed at the beginning and subsequently comproved according our experiments. Concerning bridge transducers, existing models confirmed the conditions of linearity and sensitivity related to the electrical signal. All the work done was of help on the calibration field and pressure measurements employing unbounded strain gauge pressure transducers

  2. Calibration and Data Analysis of the MC-130 Air Balance

    Science.gov (United States)

    Booth, Dennis; Ulbrich, N.

    2012-01-01

    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.

  3. Optimized balance rehabilitation training strategy for the elderly through an evaluation of balance characteristics in response to dynamic motions

    Directory of Open Access Journals (Sweden)

    Jung HH

    2015-10-01

    Full Text Available HoHyun Jung,1 Keyoung Jin Chun,2 Jaesoo Hong,2 Dohyung Lim1 1Department of Mechanical Engineering, Sejong University, Seoul, Republic of Korea; 2Smart Welfare Technology Research Group, Korea Institute of Industrial Technology, Cheonan, Republic of Korea Abstract: Balance is important in daily activities and essential for maintaining an independent lifestyle in the elderly. Recent studies have shown that balance rehabilitation training can improve the balance ability of the elderly, and diverse balance rehabilitation training equipment has been developed. However, there has been little research into optimized strategies for balance rehabilitation training. To provide an optimized strategy, we analyzed the balance characteristics of participants in response to the rotation of a base plate on multiple axes. Seven male adults with no musculoskeletal or nervous system-related diseases (age: 25.5±1.7 years; height: 173.9±6.4 cm; body mass: 71.3±6.5 kg; body mass index: 23.6±2.4 kg/m2 were selected to investigate the balance rehabilitation training using customized rehabilitation equipment. Rotation of the base plate of the equipment was controlled to induce dynamic rotation of participants in the anterior–posterior, right-diagonal, medial–lateral, and left-diagonal directions. We used a three-dimensional motion capture system employing infrared cameras and the Pedar Flexible Insoles System to characterize the major lower-extremity joint angles, center of body mass, and center of pressure. We found statistically significant differences between the changes in joint angles in the lower extremities in response to dynamic rotation of the participants (P<0.05. The maximum was greater with anterior–posterior and medial–lateral dynamic rotation than with that in other directions (P<0.05. However, there were no statistically significant differences in the frequency of center of body mass deviations from the base of support (P>0.05. These results indicate that optimizing rotation control of the base plate of balance rehabilitation training equipment to induce anterior–posterior and medial–lateral dynamic rotation preferentially can lead to effective balance training. Additional tests with varied speeds and ranges of angles of base plate rotation are expected to be useful as well as an analysis of the balance characteristics considering a balance index that reflects the muscle activity and cooperative characteristics. Keywords: optimized strategy, balance rehabilitation training, balance characteristics, maximum deviation, deviation frequency 

  4. Pressure sensor

    Science.gov (United States)

    Mee, David K.; Ripley, Edward B.; Nienstedt, Zachary C.; Nienstedt, Alex W.; Howell, Jr., Layton N.

    2015-09-29

    Disclosed is a passive, in-situ pressure sensor. The sensor includes a sensing element having a ferromagnetic metal and a tension inducing mechanism coupled to the ferromagnetic metal. The tension inducing mechanism is operable to change a tensile stress upon the ferromagnetic metal based on a change in pressure in the sensing element. Changes in pressure are detected based on changes in the magnetic switching characteristics of the ferromagnetic metal when subjected to an alternating magnetic field caused by the change in the tensile stress. The sensing element is embeddable in a closed system for detecting pressure changes without the need for any penetrations of the system for power or data acquisition by detecting changes in the magnetic switching characteristics of the ferromagnetic metal caused by the tensile stress.

  5. Pressure Alopecia

    OpenAIRE

    Davies, Kate E; Yesudian, PD

    2012-01-01

    Postoperative or pressure alopecia (PA) is an infrequently reported group of scarring and non-scarring alopecias. It has been reported after immobilization of the head during surgery and following prolonged stays on intensive care units, and may be analogous to a healed pressure ulcer. This review presents a summary of cases published in pediatrics and after cardiac, gynecological, abdominal and facial surgeries. PA may manifest as swelling, tenderness, and ulceration of the scalp in the firs...

  6. Time variable Earths gravity field from SLR satellites

    OpenAIRE

    Sosnica, Krzysztof Jakub; Jggi, Adrian; Meyer, Ulrich; Thaller, Daniela; Beutler, Gerhard; Arnold, Daniel; Dach, Rolf

    2015-01-01

    The time variable Earths gravity field contains information about the mass transport within the system Earth, i.e., the relationship between mass variations in the atmosphere, oceans, land hydrology, and ice sheets. For many years, satellite laser ranging (SLR) observations to geodetic satellites have provided valuable information of the low-degree coefficients of the Earths gravity field. Today, the Gravity Recovery and Climate Experiment (GRACE) mission is the major source of information ...

  7. Modeling the earth system

    Energy Technology Data Exchange (ETDEWEB)

    Ojima, D. [ed.

    1992-12-31

    The 1990 Global Change Institute (GCI) on Earth System Modeling is the third of a series organized by the Office for Interdisciplinary Earth Studies to look in depth at particular issues critical to developing a better understanding of the earth system. The 1990 GCI on Earth System Modeling was organized around three themes: defining critical gaps in the knowledge of the earth system, developing simplified working models, and validating comprehensive system models. This book is divided into three sections that reflect these themes. Each section begins with a set of background papers offering a brief tutorial on the subject, followed by working group reports developed during the institute. These reports summarize the joint ideas and recommendations of the participants and bring to bear the interdisciplinary perspective that imbued the institute. Since the conclusion of the 1990 Global Change Institute, research programs, nationally and internationally, have moved forward to implement a number of the recommendations made at the institute, and many of the participants have maintained collegial interactions to develop research projects addressing the needs identified during the two weeks in Snowmass.

  8. Monitoring the Earth

    Science.gov (United States)

    Vita-Finzi, Claudio

    2003-02-01

    Monitoring the Earth is the first book to review the recent advances in satellite technology, computing and mass spectrometry that are opening up completely new avenues of enquiry to Earth scientists. Among the geological changes that were previously considered too slow or too extensive for direct measurements and that can now be monitored directly are continental displacements, mountain uplift, the growth and decay of icesheets and glaciers, the faulting and folding of rocks, the progress of weathering and sedimentation, and the growth of coral reefs. In addition to these developments, the book assesses progress in fields not normally considered part of physical geology, such as the shape and orbit of the gravity and the terrestrial magnetic field. The results from the new findings are already helping Earth scientists analyze and explain the underlying mechanisms, notably with regard to the storage and release of strain during earthquakes and the interaction of glacial history with the Earth's rate of rotation. The outcoe is a foretaste of the physical geology of the space age.^Fully illustrated with line drawings and photographs, and with a bibliography that encompasses the scattered and disparate litarature, Monitoring the Earth is intended for undergraduates in geology, geomorphology, geomatic engineering and planetary science, but it should also be of interest to astronomers and historians of science.

  9. The earth's hydrological cycle

    CERN Document Server

    Bonnet, R-M; Calisto, M; Destouni, G; Gurney, R; Johannessen, J; Kerr, Y; Lahoz, WA; Rast, M

    2014-01-01

    This book gives a comprehensive presentation of our present understanding of the Earth's Hydrological cycle and the problems, consequences and impacts that go with this topic. Water is a central component in the Earth's system. It is indispensable for life on Earth in its present form and influences virtually every aspect of our planet's life support system. On relatively short time scales, atmospheric water vapor interacts with the atmospheric circulation and is crucial in forming the Earth's climate zones. Water vapor is the most powerful of the greenhouse gases and serves to enhance the tropospheric temperature. The dominant part of available water on Earth resides in the oceans. Parts are locked up in the land ice on Greenland and Antarctica and a smaller part is estimated to exist as groundwater. If all the ice over the land and all the glaciers were to melt, the sea level would rise by some 80 m. In comparison, the total amount of water vapor in the atmosphere is small; it amounts to ~ 25 kg/m2, or the ...

  10. Earth - Moon Conjunction

    Science.gov (United States)

    1992-01-01

    On December 16, 1992, 8 days after its encounter with Earth, the Galileo spacecraft looked back from a distance of about 6.2 million kilometers (3.9 million miles) to capture this remarkable view of the Moon in orbit about Earth. The composite photograph was constructed from images taken through visible (violet, red) and near-infrared (1.0-micron) filters. The Moon is in the foreground; its orbital path is from left to right. Brightly colored Earth contrasts strongly with the Moon, which reacts only about one-third as much sunlight as our world. To improve the visibility of both bodies, contrast and color have been computer enhanced. At the bottom of Earth's disk, Antarctica is visible through clouds. The Moon's far side can also be seen. The shadowy indentation in the Moon's dawn terminator--the boundary between its dark and lit sides--is the South Pole-Aitken Basin, one of the largest and oldest lunar impact features. This feature was studied extensively by Galileo during the first Earth flyby in December 1990.

  11. The Sun and Earth

    Science.gov (United States)

    Gopalswamy, Natchimuthuk

    2012-01-01

    Thus the Sun forms the basis for life on Earth via the black body radiation it emits. The Sun also emits mass in the form of the solar wind and the coronal mass ejections (CMEs). Mass emission also occurs in the form of solar energetic particles (SEPs), which happens during CMEs and solar flares. Both the mass and electromagnetic energy output of the Sun vary over a wide range of time scales, thus introducing disturbances on the space environment that extends from the Sun through the entire heliosphere including the magnetospheres and ionospheres of planets and moons of the solar system. Although our habitat is located in the neutral atmosphere of Earth, we are intimately connected to the non-neutral space environment starting from the ionosphere to the magnetosphere and to the vast interplanetary space. The variability of the solar mass emissions results in the interaction between the solar wind plasma and the magnetospheric plasma leading to huge disturbances in the geospace. The Sun ionizes our atmosphere and creates the ionosphere. The ionosphere can be severely disturbed by the transient energy input from solar flares and the solar wind during geomagnetic storms. The complex interplay between Earth's magnetic field and the solar magnetic field carried by the solar wind presents varying conditions that are both beneficial and hazardous to life on earth. This seminar presents some of the key aspects of this Sun-Earth connection that we have learned since the birth of space science as a scientific discipline some half a century ago.

  12. Earth and planetary sciences

    International Nuclear Information System (INIS)

    The earth is a dynamic body. The major surface manifestation of this dynamism has been fragmentation of the earth's outer shell and subsequent relative movement of the pieces on a large scale. Evidence for continental movement came from studies of geomagnetism. As the sea floor spreads and new crust is formed, it is magnetized with the polarity of the field at the time of its formation. The plate tectonics model explains the history, nature, and topography of the oceanic crust. When a lithospheric plate surmounted by continental crust collides with an oceanic lithosphere, it is the denser oceanic lithosphere that is subducted. Hence the ancient oceans have vanished and the knowledge of ancient earth will require deciphering the complex continental geological record. Geochemical investigation shows that the source region of continental rocks is not simply the depleted mantle that is characteristic of the source region of basalts produced at the oceanic ridges. The driving force of plate tectonics is convection within the earth, but much remains to be learned about the convection and interior of the earth. A brief discussion of planetary exploration is given

  13. Google Earth and Map Projections

    OpenAIRE

    Nedjeljko Fran?ula

    2010-01-01

    By starting Google Earth, the screen shows Earth from a great distance, e.g. from a satellite rotating around the Earth (Fig. 1). The graticule is drawn by using the Grid function from the View menu. Google Earth is a virtual globe which can be rotated in all directions using a mouse.

  14. Solar activity and earth's climate

    CERN Document Server

    Benestad, Rasmus E

    2006-01-01

    Introduces the subject of solar activity and the connection with Earth''s climate. This book commences with a review of the historical progress on the understanding of the solar-terrestrial connection and moves on to an objective scrutiny of the various hypothesis. It focuses on how knowledge about the solar cycle and Earth''s climate is obtained.

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

    Science.gov (United States)

    Spohn, Tilman

    2013-04-01

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

  16. Skylab water balance error analysis

    Science.gov (United States)

    Leonard, J. I.

    1977-01-01

    Estimates of the precision of the net water balance were obtained for the entire Skylab preflight and inflight phases as well as for the first two weeks of flight. Quantitative estimates of both total sampling errors and instrumentation errors were obtained. It was shown that measurement error is minimal in comparison to biological variability and little can be gained from improvement in analytical accuracy. In addition, a propagation of error analysis demonstrated that total water balance error could be accounted for almost entirely by the errors associated with body mass changes. Errors due to interaction between terms in the water balance equation (covariances) represented less than 10% of the total error. Overall, the analysis provides evidence that daily measurements of body water changes obtained from the indirect balance technique are reasonable, precise, and relaible. The method is not biased toward net retention or loss.

  17. Fuel cycle balance of Phenix

    International Nuclear Information System (INIS)

    The Phenix fuel cycle balance is presented after 16 years of reactor operation. After a brief presentation of the cycle operations, this report is consecrated at the burnup influence and its repercussion on the cycle

  18. Aging: Balancing regeneration and cancer

    Energy Technology Data Exchange (ETDEWEB)

    Beausejour, Christian M.; Campisi, Judith

    2006-08-24

    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.

  19. Are Social Networks Really Balanced?

    CERN Document Server

    Estrada, Ernesto

    2014-01-01

    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.

  20. Laboratory Workhorse: The Analytical Balance.

    Science.gov (United States)

    Clark, Douglas W.

    1979-01-01

    This report explains the importance of various analytical balances in the water or wastewater laboratory. Stressed is the proper procedure for utilizing the equipment as well as the mechanics involved in its operation. (CS)