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Sample records for earth pressure balance

  1. Earth pressure balance control for EPB shield

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    This paper mainly deals with the critical technology of earth pressure balance (EPB) control in shield tunneling. On the assumption that the conditioned soil in the working chamber of the shield is plasticized, a theoretical principle for EPB control is proposed. Dynamic equilibrium of intake volume and discharge volume generated by thrust and discharge is modeled theoretically to simulate the earth pressure variation during excavating. The thrust system and the screw conveyor system for earth pressure control are developed based on the electro-hydraulic technique. The control models of the thrust speed regulation of the cylinders and the rotating speed adjustment of the screw conveyor are also presented. Simulation for earth pressure control is conducted with software AMESim and MATLAB/Simulink to verify the models. Experiments are carried out with intake control in clay soil and discharge control in sandy gravel section, respectively. The experimental results show that the earth pressure variations in the working chamber can be kept at the expected value with a practically acceptable precision by means of real-time tuning the thrust speed or the revolving speed of discharge system.

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

    OpenAIRE

    Martinelli, D; D. Peila; 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...

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

    Directory of Open Access Journals (Sweden)

    D. Martinelli

    2015-12-01

    Full Text Available 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 usually used in cohesive materials, and a direct shear test. The laboratory test proves that the test procedure is applicable also to this type of soil and the conditioned material can be considered suitable for EPB excavations, although it is necessary to use a certain percentage of fine elements (filler to create a material suitable to be mixed with foam. The test results show that the conditioned material fulfils the required standard for an EPB application.

  4. Experimental study on working parameters of earth pressure balance shield machine tunneling in soft ground

    Institute of Scientific and Technical Information of China (English)

    Hehua ZHU; Shaoming LIAO; Qianwei XU; Qizhen ZHENG

    2008-01-01

    Deep sedimentary deposits of soft clays are widely distributed in coastal areas as well as many interior major cities in China. In order to study the stratum adapt-ability of earth pressure balance (EPB) shield machine tunneling in such types of soft ground, model tests of tunneling excavation, using the running tunnel of the Shanghai Metro Line M8 as a background, are carried out with different over burden ratios, opening rates of cutter head, driving speeds and rotation speeds of screw conveyor. Based on the test results, the interrelationships between chamber pressure and mucking efficiency, muck-ing rate and driving speed, thrust force and torque are obtained. The influences of tunnel depth, opening rate of cutter head and driving speed on thrust force and tor-que are revealed. Such findings can not only facilitate establishing relationships between shield working para-meters and soil properties, but also serve as a guide for the design and construction of shield tunnel in soft ground.

  5. 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

    2016-05-01

    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.

  6. Pressure balance at the magnetopause: Experimental studies

    OpenAIRE

    Suvorova, A. V.; Dmitriev, A. V.

    2011-01-01

    The pressure balance at the magnetopause is formed by magnetic field and plasma in the magnetosheath, on one side, and inside the magnetosphere, on the other side. In the approach of dipole earth's magnetic field configuration and gas-dynamics solar wind flowing around the magnetosphere, the pressure balance predicts that the magnetopause distance R depends on solar wind dynamic pressure Pd as a power low R ~ Pd^alpha, where the exponent alpha=-1/6. In the real magnetosphere the magnetic file...

  7. 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...

  8. Pressure-Balance Consistency in Magnetospheric Modelling

    Institute of Scientific and Technical Information of China (English)

    肖永登; 陈出新

    2003-01-01

    There have been many magnetic field models for geophysical and astrophysical bodies.These theoretical or empirical models represent the reality very well in some cases,but in other cases they may be far from reality.We argue that these models will become more reasonable if they are modified by some coordinate transformations.In order to demonstrate the transformation,we use this method to resolve the "pressure-balance inconsistency"problem that occurs when plasma transports from the outer plasma sheet of the Earth into the inner plasma sheet.

  9. Computerized Techniques for Calibrating Pressure Balances

    Science.gov (United States)

    Simpson, D. I.

    1994-01-01

    Pressure balances are generally calibrated by the cross-floating technique, where the forces acting on two similar devices in hydrostatic equilibrium are compared. It is a skilled and time-consuming process which has not previously lent itself to significant automation; computers have mostly been used only to calculate results after measurements have been taken. The objective of the present work was to develop real-time computerized measurement techniques to ease the calibration task, which would fully integrate into a single package with versatile software for calculating and displaying results. The calibration process is now conducted by studying graphical computer displays which derive their inputs from differential-pressure transducers and capacitance or optical displacement sensors. The mass imbalance between oil-operated pressure balances is calculated by interpolating between changes in piston rate-of-fall. Differential-pressure transducers are used to estimate mass imbalances between gas-operated balances, and a quick in situ method for determining their sensitivity has been developed. The new techniques have been successfully applied to a variety of pressure balance designs and substantial reductions in calibration times have been achieved. Reduced levels of scatter have revealed small systematic differences between gauge and absolute modes of operation.

  10. 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

  11. 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.

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

    NARCIS (Netherlands)

    Bruin, de H.A.R.

    1982-01-01

    This study is devoted to the energy balance of the earth's surface with a special emphasis on practical applications. A simple picture of the energy exchange processes that take place at the ground is the following. Per unit time and area an amount of radiant energy is supplied to the surface. This

  13. 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

  14. 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....

  15. AN APPROXIMATION TO LATERAL EARTH PRESSURES FOR K0 CONDITION

    Directory of Open Access Journals (Sweden)

    M. Arslan TEKİNSOY

    1999-01-01

    Full Text Available In this study, the determination of lateral earth pressures of soils or Ko parameter is considered. For this effect, the deformation and the variations in the shear stresses of the soils placed in an oedometer set up were investigated. Based on this data, a general method which can be used in the calculation of lateral pressures of soils has been proposed. The study was carried out on a cohesive soil having two different group symbol and sandy soils with different relative densities. The lateral pressure values measured by thin wall oedometer technique are in very good agreement with those obtained by calculation. In conclusion, lateral earth pressures or the Ko values are depend upon the distribution of the samples, their relative density and consistancy, the magnitude of the pre-consolidation pressure. The proposed method is a simple and economic technique as regards to the approximation and experimentation.

  16. Stability of hydrocarbons at deep Earth pressures and temperatures

    OpenAIRE

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

    2011-01-01

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

  17. 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

  18. 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.

  19. 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

  20. 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

  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. New weight-handling device for commercial oil pressure balances

    Science.gov (United States)

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

    2005-12-01

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

  3. Dual shell pressure balanced reactor vessel. Final project report

    International Nuclear Information System (INIS)

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

  4. 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

  5. COMPUTER SIMULATION OF VENTILATION PRESSURE BALANCING FOR THE PREVENTION OF SPONTANEOUS COMBUSTION IN MINES

    Institute of Scientific and Technical Information of China (English)

    周心权; 吴兵

    1995-01-01

    Qualitative analysis plus trial and error method are still the routine to achieve ventilation pressure balancing. These methods may cause large errors in pressure balancing so that sometimes the spontaneous combustion can not be extnguished effectively. This paper introduces a quantitative analysis of pressure balancing for different causes of ventilation networks and develops a computer program (SPFPB) specifically written for pressure balancing between faces and connected gobs. It allows a user to choose different methods to meet his various needs and the underground conditions. The different balancing results are compared, and the proper locations and sizes of the control devices are recommended.

  6. Pressure-induced exotic states in rare earth hexaborides

    Science.gov (United States)

    Sun, Liling; Wu, Qi

    2016-08-01

    Finding the exotic phenomena in strongly correlated electron systems (SCESs) and understanding the corresponding microphysics have long been the research frontiers of condensed matter physics. The remarkable examples for the intriguing phenomena discovered in past years include unconventional superconductivity, heavy Fermion behaviors, giant magneto-resistance and so on. A fascinating type of rare earth hexaboride RB6 (R  =  Sm, Yb, Eu and Ce) belongs to a strongly correlated electron system (SCES), but shows unusual ambient-pressure and high-pressure behaviors beyond the phenomena mentioned above. Particularly, the recent discovery of the coexistence of an unusual metallic surface state and an insulating bulk state in SmB6, known to be a Kondo insulator decades ago, by theoretical calculations and many experimental measurements creates new interest for the investigation of the RB6. This significant progress encourages people to revisit the RB6 with an attempt to establish a new physics that links the SCES and the unusual metallic surface state which is a common feature of a topological insulator (TI). It is well known that pressure has the capability of tuning the electronic structure and modifying the ground state of solids, or even inducing a quantum phase transition which is one of the kernel issues in studies of SCESs. In this brief review, we will describe the progress in high pressure studies on the RB6 based on our knowledge and research interests, mainly focusing on the pressure-induced phenomena in YbB6 and SmB6, especially on the quantum phase transitions and their connections with the valence state of the rare earth ions. Moreover, some related high-pressure results obtained from CeB6 and EuB6 are also included. Finally, a summary is given in the conclusions and perspectives section.

  7. Pressure-induced exotic states in rare earth hexaborides.

    Science.gov (United States)

    Sun, Liling; Wu, Qi

    2016-08-01

    Finding the exotic phenomena in strongly correlated electron systems (SCESs) and understanding the corresponding microphysics have long been the research frontiers of condensed matter physics. The remarkable examples for the intriguing phenomena discovered in past years include unconventional superconductivity, heavy Fermion behaviors, giant magneto-resistance and so on. A fascinating type of rare earth hexaboride RB6 (R  =  Sm, Yb, Eu and Ce) belongs to a strongly correlated electron system (SCES), but shows unusual ambient-pressure and high-pressure behaviors beyond the phenomena mentioned above. Particularly, the recent discovery of the coexistence of an unusual metallic surface state and an insulating bulk state in SmB6, known to be a Kondo insulator decades ago, by theoretical calculations and many experimental measurements creates new interest for the investigation of the RB6. This significant progress encourages people to revisit the RB6 with an attempt to establish a new physics that links the SCES and the unusual metallic surface state which is a common feature of a topological insulator (TI). It is well known that pressure has the capability of tuning the electronic structure and modifying the ground state of solids, or even inducing a quantum phase transition which is one of the kernel issues in studies of SCESs. In this brief review, we will describe the progress in high pressure studies on the RB6 based on our knowledge and research interests, mainly focusing on the pressure-induced phenomena in YbB6 and SmB6, especially on the quantum phase transitions and their connections with the valence state of the rare earth ions. Moreover, some related high-pressure results obtained from CeB6 and EuB6 are also included. Finally, a summary is given in the conclusions and perspectives section. PMID:27376406

  8. 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...

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

    OpenAIRE

    Kissinger, Jennifer Eileen

    2012-01-01

    Magnetic reconnection between Earth's magnetosphere and the solar wind results in several modes of response, including the impulsive substorm and the quasi-steady mode known as steady magnetospheric convection (SMC). SMC events are theorized to result from balancing the dayside and nightside reconnection rates. The reasons the magnetosphere responds with different modes are not fully known. This dissertation comprises statistical data analysis of the SMC mode to investigate the solar wind con...

  10. INVESTIGATION INTO EFFECT OF SPRING PRESSURE ON PERFORMANCE OF BALANCED MECHANICAL SEALS

    Institute of Scientific and Technical Information of China (English)

    SUN Jianjun; GU Boqin

    2007-01-01

    The loads acting on the sealing elements of balanced mechanical seals are analyzed. When the balance factor approaches the back pressure factor, the spring pressure will become main part of the face pressure. The leakage model of balanced mechanical seals is established on the base of M-B model for rough surface. Several GY-70 type balanced mechanical seals are tested. The influences of the spring pressure both on the leakage rate and on the friction characteristic of balanced mechanical seals are investigated. The research results indicate that as spring pressure increases, both the clearance between two end faces and the leakage rate will decrease, and the friction will be more serious because lubrication medium between the rotating ring and the stationary ring reduces, though the increase of the spring pressure may not be enough to change the face friction state of mechanical seals. There exists an optimum spring pressure for mechanical seal operation. Under this spring pressure, not only leakage rate is small, but also the seal end surfaces have a fine friction characteristic.Under different operating conditions, identical type mechanical seals may possess different spring pressure. Appropriate selection of spring pressure is valuable to realize long-period and small leakage rate operating of balanced mechanical seals.

  11. A Mechanism of Solar Variability Effect on Radiative Balance of the Earth Atmosphere

    Institute of Scientific and Technical Information of China (English)

    G. A. Zherebtsov; V.A. Kovalenko; S.I. Molodykh

    2005-01-01

    Possible mechanisms of solar-climatic connections, which may be of importance as over short and long time intervals, are discussed. The variations of energetic balance of Earth's climatic system for the last fifty years are estimated. It is ascertained that the disbalance between the flux of solar energy that comes to the Earth and radiates to space is of 0.1% for the last ten years. The suggested mechanism makes it possible to explain not only the observed variation of the enthalpy of the Earth's climatic system for the period 1910-1980, but also the climate anomalies during last thousand years: the climate optimum in 12 century, and"small glacial period" in 16-17 centuries.

  12. Simulation of the Earth's gravitational field recovery from GRACE using the energy balance approach

    Institute of Scientific and Technical Information of China (English)

    ZHENG Wei; LU Xiaolei; HSU Houtse; SHAO Chenggang; LUO Jun; WANG Nengchao

    2005-01-01

    Based on the measurement principles of GRACE satellites, the observation equations are set up using the energy balance approach. The Earth's gravitational field complete up to degree and order 120 is recovered applying the preconditioning conjugate gradient iterative approach by numerical simulation. Assuming an accuracy of 1?m/s in range-rate measurements of the K-band microwave ranging system, the matching relationships of accuracies of K-band microwave ranging system, SuperSTAR Accelerometer, position vector and velocity vector measurements are investigated.

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

    OpenAIRE

    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 sa...

  14. 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...

  15. 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.…

  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

  17. Research on Earth's rotation and the effect of atmospheric pressure on vertical deformation and sea level variability

    Science.gov (United States)

    Wahr, John

    1993-03-01

    The work done under NASA grant NAG5-485 included modelling the deformation of the earth caused by variations in atmospheric pressure. The amount of deformation near coasts is sensitive to the nature of the oceanic response to the pressure. The PSMSL (Permanent Service for Mean Sea Level) data suggest the response is inverted barometer at periods greater than a couple months. Green's functions were constructed to describe the perturbation of the geoid caused by atmospheric and oceanic loading and by the accompanying load-induced deformation. It was found that perturbation of up to 2 cm are possible. Ice mass balance data was used for continental glaciers to look at the glacial contributions to time-dependent changes in polar motion, the lod, the earth's gravitational field, the position of the earth's center-of-mass, and global sea level. It was found that there can be lateral, non-hydrostatic structure inside the fluid core caused by gravitational forcing from the mantle, from the inner core, or from topography at the core/mantle or inner core/outer core boundaries. The nutational and tidal response of a non-hydrostatic earth with a solid inner core was modeled. Monthly, global tide gauge data from PSMSL was used to look at the 18.6-year ocean tide, the 14-month pole tide, the oceanic response to pressure, the linear trend and inter-annual variability in the earth's gravity field, the global sea level rise, and the effects of post glacial rebound. The effects of mantle anelasticity on nutations, earth tides, and tidal variation in the lod was modeled. Results of this model can be used with Crustal Dynamics observations to look at the anelastic dissipation and dispersion at tidal periods. The effects of surface topography on various components of crustal deformation was also modeled, and numerical models were developed of post glacial rebound.

  18. Balancing food and predator pressure induces chronic stress in songbirds.

    OpenAIRE

    Clinchy, Michael; Zanette, Liana; Boonstra, Rudy; Wingfield, John C.; Smith, James N. M.

    2004-01-01

    The never-ending tension between finding food and avoiding predators may be the most universal natural stressor wild animals experience. The 'chronic stress' hypothesis predicts: (i) an animal's stress profile will be a simultaneous function of food and predator pressures given the aforesaid tension; and (ii) these inseparable effects on physiology will produce inseparable effects on demography because of the resulting adverse health effects. This hypothesis was originally proposed to explain...

  19. 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.

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

    Directory of Open Access Journals (Sweden)

    A. Sekkel

    2013-10-01

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

  1. Study on the Test Method of Static Earth Pressure Coefficient of Deep Soils

    Institute of Scientific and Technical Information of China (English)

    XU Zhi-wei; ZHOU Guo-qing; LIU Zhi-qiang; ZHAO Xiao-dong; LI Sheng-sheng; ZHANG Lei

    2007-01-01

    The static earth pressure coefficient of soils is, approximately, considered to be a constant in the view of classical soil mechanics. This is supported by many research results. The high pressure experimental research and analysis of remolding deep soil described herein indicate that the static earth pressure of thick overburden has a notable non linear characteristic. It also appears larger than that of superficial soils. It is necessary for deep coal mine design and construction to consider this particularity of soil pressure so as to avoid engineering accidents and heavy loss of life and property.

  2. Dynamic Active Earth Pressures of the Retaining Piles with Anchors under Vehicle Loads

    OpenAIRE

    Hong-zhi Qiu; Ji-ming Kong; Ren-chao Wang

    2016-01-01

    The pile-anchor supporting structure is widely used in foundation pit engineering; then knowledge of active earth pressure on piles is very important for engineers. In this paper, based on the pseudodynamic method and considering the vehicle’s vibration characteristic, a method to calculate the earth pressure on piles under vehicle load is presented. At the same time, the constraint of anchor is simplified relation of lateral deformation of piles in present method. Effects of a wide range of ...

  3. Study on the Seismic Active Earth Pressure by Variational Limit Equilibrium Method

    Directory of Open Access Journals (Sweden)

    Jiangong Chen

    2016-01-01

    Full Text Available In the framework of limit equilibrium theory, the isoperimetric model of functional extremum regarding the seismic active earth pressure is deduced according to the variational method. On this basis, Lagrange multipliers are introduced to convert the problem of seismic active earth pressure into the problem on the functional extremum of two undetermined function arguments. Based on the necessary conditions required for the existence of functional extremum, the function of the slip surface and the normal stress distribution on the slip surface is obtained, and the functional extremum problem is further converted into a function optimization problem with two undetermined Lagrange multipliers. The calculated results show that the slip surface is a plane and the seismic active earth pressure is minimal when the action point is at the lower limit position. As the action point moves upward, the slip surface becomes a logarithmic spiral and the corresponding value of seismic active earth pressure increases in a nonlinear manner. And the seismic active earth pressure is maximal at the upper limit position. The interval estimation constructed by the minimum and maximum values of seismic active earth pressure can provide a reference for the aseismic design of gravity retaining walls.

  4. Dynamic Active Earth Pressures of the Retaining Piles with Anchors under Vehicle Loads

    Directory of Open Access Journals (Sweden)

    Hong-zhi Qiu

    2016-01-01

    Full Text Available The pile-anchor supporting structure is widely used in foundation pit engineering; then knowledge of active earth pressure on piles is very important for engineers. In this paper, based on the pseudodynamic method and considering the vehicle’s vibration characteristic, a method to calculate the earth pressure on piles under vehicle load is presented. At the same time, the constraint of anchor is simplified relation of lateral deformation of piles in present method. Effects of a wide range of parameters like rupture angle, vibration acceleration coefficient, wall friction angle, and soil friction angle on active earth pressure have been studied. Results are presented in terms of coefficients in the figures and comparison of the test data and the earth pressure calculated by M-O method and present study. The result shows that the measured earth pressure is accordant with the theoretical analysis, so the method in this paper is an effective basis for the calculation of earth pressure on piles under vehicle loads.

  5. Effect of impeller reflux balance holes on pressure and axial force of centrifugal pump

    Institute of Scientific and Technical Information of China (English)

    CAO Wei-dong; DAI Xun; HU Qi-xiang

    2015-01-01

    The size of impeller reflux holes for centrifugal pump has influence on the pressure distribution of front and rear shrouds and rear pump chamber, as well as energy characteristics of whole pump and axial force. Low specific-speed centrifugal pump with Q=12.5 m3/h,H=60 m,n=2950 r/min was selected to be designed with eight axial reflux balance holes with 4.5 mm in diameter. The simulated Q-H curve and net positive suction head (NPSH) were in good agreement with experimental results, which illustrated that centrifugal pump with axial reflux balance holes was superior in the cavitation characteristic; however, it showed to little superiority in head and efficiency. The pressure in rear pump chamber at 0.6 times rate flow is 29.36% of pressure difference between outlet and inlet, which reduces to 29.10% at rate flow and 28.33% at 1.4 times rate flow. As the whole, the pressure distribution on front and rear shrouds from simulation results is not a standard parabola, and axial force decreases as flow rate increases. Radical reflux balance holes chosen to be 5.2 mm and 5.9 mm in diameter were further designed with other hydraulic parts unchanged. With structural grids adopted for total flow field, contrast numerical simulation on internal flow characteristics was conducted based on momentum equations and standard turbulence model (κ-ε). It is found that axial force of pump with radical reflux balance holes of 5.2 mm and 5.9 mm in diameter is significantly less than that with radical reflux balance holes of 4.5 mm in diameter. Better axial force balance is obtained as the ratio of area of reflux balance holes and area of sealing ring exceeds 6.

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

    NARCIS (Netherlands)

    Nagendra, H.; Mairota, P.; Marangi, C.; Lucas, R.; Dimopoulos, P.; Honrado, J.P.; Niphadkara, M.; Mücher, C.A.; Tomaselli, V.; Panitsa, M.; Tarantino, C.; Manakos, I.; Blonda, P.

    2015-01-01

    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)

  7. Salt balance: From space experiments to revolutionizing new clinical concepts on earth - A historical review

    Science.gov (United States)

    Gerzer, Rupert

    2014-11-01

    For a long time, sodium balance appeared to be a “done deal” and was thought to be well understood. However, experiments in preparation of space missions showed that the concept of osmotic sodium storage and close correlations of sodium with water balance are only part of the regulatory mechanisms of body salt. By now it has turned out that the human skin is an important storage place and regulator for sodium, that sodium storage involves macrophages which in turn salt-dependently co-regulate blood pressure, that body sodium also strongly influences bone and protein metabolism, and that immune functions are also strongly influenced by sodium. In addition, the aging process appears to lead to increased body sodium storage, which in turn might influence the aging process of the human body. The current review article summarizes the developments that have led to these revolutionizing new findings and concepts as well as consequences deriving from these findings. Therefore, it is not intended in this article to give a complete literature overview over the whole field but to focus on such key literature and considerations that led to the respective developments.

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

    Science.gov (United States)

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

  9. Lateral Earth Pressure behind Walls Rotating about Base considering Arching Effects

    Directory of Open Access Journals (Sweden)

    Dong Li

    2014-01-01

    Full Text Available In field, the earth pressure on a retaining wall is the common effect of kinds of factors. To figure out how key factors act, it has taken into account the arching effects together with the contribution from the mode of displacement of a wall to calculate earth pressure in the proposed method. Based on Mohr circle, a conversion factor is introduced to determine the shear stresses between artificial slices in soil mass. In the light of this basis, a modified differential slices solution is presented for calculation of active earth pressure on a retaining wall. Comparisons show that the result of proposed method is identical to observations from model tests in prediction of lateral pressures for walls rotating about the base.

  10. High Pressure Earth Storable Rocket Technology Program: Basic Program

    Science.gov (United States)

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

    1995-01-01

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

  11. High Pressure, Earth-storable Rocket Technology. Volume 2

    Science.gov (United States)

    Jassowski, D. M.

    1997-01-01

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

  12. High Pressure, Earth-storable Rocket Technology. Volume 1

    Science.gov (United States)

    Jassowski, D. M.

    1997-01-01

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

  13. A novel pneumatic micropipette aspiration method using a balance pressure model

    Science.gov (United States)

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

    2013-12-01

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

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

    Institute of Scientific and Technical Information of China (English)

    Ozgur L. Ertugrul; Aurelian C. Trandafir

    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 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 in-clusion 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

  15. Effect of balanced low pressure drying of curcuma longa leaf on skin immune activation activities.

    Science.gov (United States)

    Choi, Wooseok; Lim, Hye Won; Lee, Hyeon Yong

    2014-01-01

    The effect of balanced low pressure drying pretreatment associated with ultrasonication extraction (BU) on the enhancement of skin immune modulatory activities of Curcuma longa leaf was studied by comparing with conventional hot air drying (HE), freeze drying (FE) and balanced low pressure drying (BE) pretreatment processes. In considering skin immune activation activities such as the inhibition of hyaluronidase activity, the BU extract showed ca. 10% higher than those of HE, and even higher than that of the FE extract. Nitric oxide production from macrophage of the BU extract in adding 1.0 mg/mL was increased up to 16.5 μM. When measuring inhibition of IL-6 and TNF-a production from the human T lymphocytes (T cell), the BU extract also showed 53% and 78% of inhibition effect, respectively. It is found that the BU extract could effectively suppress the expression levels of skin inflammation related genes such as Cox-2 and iNOS, down to 80% and 85% compared to the control, respectively. Balanced low pressure drying process was especially active on dehydration of the leaves with minimizing the destruction and making easier elution of the bioactive substances, which resulted in higher extraction yield and better biological activities.

  16. Solar radiation pressure used for formation flying control around the Sun-Earth libration point

    Institute of Scientific and Technical Information of China (English)

    Sheng-ping GONG; Jun-feng LI; He-xi BAOYIN

    2009-01-01

    Solar radiation pressure is used to control the formation flying around the L2 libration point in the Sun-Earth system. Formation flying control around a halo orbit requires a very small thrust that cannot be satisfied by the latest thrusters. The key contribution of this paper is that the continuous low thrust is produced by solar radiation pressure to achieve the tight formation flying around the libration point. However, only certain families of formation types can be controlled by solar radiation pressure since the direction of solar radiation pressure is restricted to a certain range. Two types of feasible formations using solar radiation pressure control are designed. The conditions of feasible formations are given analytically. Simulations are presented for each case, and the results show that the formations are well controlled by solar radiation pressure.

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

    DEFF Research Database (Denmark)

    Krogsbøll, Anette Susanne; Fuglsang, Leif D

    2006-01-01

    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...

  18. Earth Pressure at rest of Søvind Marl – a highly overconsolidated Eocene clay

    DEFF Research Database (Denmark)

    Grønbech, Gitte Lyng; Ibsen, Lars Bo; Nielsen, Benjaminn Nordahl

    2016-01-01

    with a constant rate of strain were conducted on Søvind Marl in the Danish Continuous Loading Oedometer Apparatus, which enables test water to be applied at 200 kPa, and measures the horizontal stresses via pressure gauges placed in a stiff oedometer ring. The horizontal and vertical stresses were measured from......The present study evaluated earth pressure at rest, K0, in highly overconsolidated Eocene clay called Søvind Marl, which exhibits extremely high plasticity indices of up to 300%, a highly fissured structure, and preconsolidation stresses up to 6,800 kPa. Continuous Loading Oedometer (CLO) tests...... in situ stresses to various stress levels to estimate continuous K0 development in this highly overconsolidated clay. The normally consolidated earth pressure at rest was found for two different sample ages of Søvind Marl to be between 0.42 and 0.68. Results indicated the overconsolidated K0 reached...

  19. Coefficients of earth pressure at rest in thick and deep soils

    Institute of Scientific and Technical Information of China (English)

    TIAN Qiu-hong; XU Zhi-wei; ZHOU Guo-qing; ZHAO Xiao-dong; HU Kun

    2009-01-01

    The effect of test methods and stress paths on the experimental value of the coefficient of earth pressure at rest, K0, was investigated under high pressures. The results indicate that the rigid pressure chamber and flexible lateral confining pressure medium method gives a stress ratio at the initial stage that is not the real K0. Moreover, K0 increases during the loading process becoming greater at high pressures. In the unloading process, however, K0 increases only at the initial stage but decreases thereafter. In addition, the incremental magnitude definition, K0=dσ3/dσ1, gives higher values than the total magnitude definition, K0=σ3/σ1, under loading. This is also true during initial stages of unloading. The experiment results also indicate that earth pressure at rest in deep and thick soils can be estimated by a power function of axial and confining pressures. R is necessary to choose the appropriate Ko to avoid some accidents.

  20. 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.

  1. 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)

  2. Progesterone reduces sympathetic tone without changing blood pressure or fluid balance in men.

    Science.gov (United States)

    Tollan, A; Oian, P; Kjeldsen, S E; Eide, I; Maltau, J M

    1993-01-01

    There is scant information on the effects of progesterone on circulation. Changes in catecholamine levels, blood pressure and transcapillary fluid balance were measured in 12 men before and during administration of natural progesterone (Utrogestan). Before administration, systolic blood pressure was significantly correlated with venous adrenaline (r = 0.67, p = 0.01). There was a significant decrease (p = 0.004) in venous noradrenaline during progesterone administration, and systolic blood pressure was significantly correlated with the arteriovenous difference for noradrenaline (r = 0.66, p = 0.02). Serum progesterone, which attained levels similar to those found in women during the luteal phase, did not significantly alter blood pressure, body weight or intra- to extravascular fluid shift. It is concluded that progesterone may have a direct action by increasing the uptake of noradrenaline from the synaptic cleft or by decreasing the nerve firing rate. Interestingly, the pretreatment finding of a significant correlation between blood pressure and adrenaline was less evident during progesterone administration.

  3. STUDY ON THE OVERALL PRESSURE BALANCE OF A DOWNFLOW CIRCULATING FLUIDIZED BED SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Hengzhi Chen; Dawei Yang; Hongzhong Li; Shiyu Tan

    2006-01-01

    A pressure balance model for a circulating fluidized bed unit that incorporates a downer has been proposed. The model predictions were validated with the experimental data obtained from a special cold-model circulating fluidized bed. Comparison of the operation stability between a CFB downer and a CFB riser has been carried out. Only one critical gas velocity exists in the CFB-riser for a given riser solids flux, while there can be many critical gas velocities for the operation of a CFB downer. Therefore, it is possible to achieve high solids concentration in a CFB downer if appropriate operating conditions are used.

  4. Education for healthy body weight: helping adolescents balance the cultural pressure for thinness.

    Science.gov (United States)

    Collins, M E

    1988-08-01

    Though education for healthy body weight traditionally has focused on obesity, the increased incidence of anorexia nervosa and bulimia among young women suggests education also is needed to address the opposite end of the spectrum. Anorexia nervosa and bulimia are complex and multidimensional disorders associated with individual, family, and sociocultural factors. This article examines the cultural pressure for dieting and thinness currently experienced in America and its impact as a possible predisposing factor for developing eating disorders among adolescent females. Literature is reviewed related to the changing American standard of attractiveness for females reflected by 20th century mass media and its subsequent influence on adolescent concerns for dieting and thinness. Preventive strategies are recommended to help adolescents balance the cultural pressure for thinness and their own desires for attractiveness within the larger context of overall good health. PMID:3216626

  5. 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.

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

    Science.gov (United States)

    André, 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 s-1. 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.

  7. 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...

  8. Seismic Earth Pressures of Retaining Wall from Large Shaking Table Tests

    Directory of Open Access Journals (Sweden)

    Changwei Yang

    2015-01-01

    Full Text Available To ascertain seismic response of retaining wall in the Wenchuan earthquake, large shaking table tests are performed and an acceleration record is acted in 3 directions. In the tests, acceleration time history recorded at Wolong station in the Wenchuan earthquake is used to excite the model wall. Results from the tests show that the location of dynamic resultant earth pressure is 0.35–0.49 H from toe of the wall for road shoulder retaining wall on rock foundation, 0.33–0.42 H for embankment retaining wall on rock foundation, and 0.46–0.77 H for road shoulder retaining wall on soil foundation. Besides, dynamic earth pressure increases with the increase of ground shaking from 0.1 g to 0.9 g and the relationship is nonlinear. The distribution is closed to for PGA less than 0.4 g but larger for PGA larger than and equal to 0.4 g, especially on the soil foundation. After the comparison of measured earth pressures and theoretical results by pseudodynamic method and pseudostatic method, results of the former are consistent with those of the shaking table test, but results of the latter method are smaller than measured.

  9. "Nonlinear" characteristics of the static earth pressure coefficient in thick alluvium

    Institute of Scientific and Technical Information of China (English)

    XU Zhi-wei; ZENG Kai-hua; WEI Zhou; LIU Zhi-qiang; ZHAO Xiao-dong; TIAN Qiu-hong

    2009-01-01

    Exact calculations of the static earth pressure from a thick alluvium require accurate K0 values. These calculations influence the sinking cost and the safety of the freezing method. The static earth pressure coefficient (K0) of thick and deep soil was analyzed using laboratory tests. The results show that the static earth pressure coefficient of thick and deep soils is nonlinear and different from that of superficial soils. The constant of superficial soils is usually invariant and the total stress or incremental stress definitions used in traditional geo-mechanics give the same value. The influence of load increments when calculating for superficial soil is ignored. The difference in values of K0 for thick alluvium defined by the total stress or the incremental stress methods is over 10%. The effects of the thick alluvium on K0 should be considered during the design of frozen shaft projects. Such things as the frozen shaft thickness and the excavated section height should be chosen to assure the rationality of the design and to avoid potential faults and accidents.

  10. Dualistic Chemical Evolution to the Stabilization of the Energy-Balance: A Hypothesis on the Origin of Life on the Earth

    OpenAIRE

    Matsuda, Genji

    2004-01-01

    A hypothesis of the dualistic chemical evolution to the stabilization of the energy-balance is proposed and explained in connection with the origin of life on the earth. From author's viewpoint, the existence of all things and all phenomena in the universe are closely related to the stabilization of the energy-balance and life is not an exceptional case in this matter. It is presumed that the first life on the earth was formed as the process towards the stabilization of the energy-balance by ...

  11. The Balance of Fluid and Osmotic Pressures across Active Biological Membranes with Application to the Corneal Endothelium.

    Directory of Open Access Journals (Sweden)

    Xi Cheng

    Full Text Available The movement of fluid and solutes across biological membranes facilitates the transport of nutrients for living organisms and maintains the fluid and osmotic pressures in biological systems. Understanding the pressure balances across membranes is crucial for studying fluid and electrolyte homeostasis in living systems, and is an area of active research. In this study, a set of enhanced Kedem-Katchalsky (KK equations is proposed to describe fluxes of water and solutes across biological membranes, and is applied to analyze the relationship between fluid and osmotic pressures, accounting for active transport mechanisms that propel substances against their concentration gradients and for fixed charges that alter ionic distributions in separated environments. The equilibrium analysis demonstrates that the proposed theory recovers the Donnan osmotic pressure and can predict the correct fluid pressure difference across membranes, a result which cannot be achieved by existing KK theories due to the neglect of fixed charges. The steady-state analysis on active membranes suggests a new pressure mechanism which balances the fluid pressure together with the osmotic pressure. The source of this pressure arises from active ionic fluxes and from interactions between solvent and solutes in membrane transport. We apply the proposed theory to study the transendothelial fluid pressure in the in vivo cornea, which is a crucial factor maintaining the hydration and transparency of the tissue. The results show the importance of the proposed pressure mechanism in mediating stromal fluid pressure and provide a new interpretation of the pressure modulation mechanism in the in vivo cornea.

  12. Dynamic and structural properties of orthorhombic rare-earth manganites under high pressure

    Science.gov (United States)

    Mota, D. A.; Almeida, A.; Rodrigues, V. H.; Costa, M. M. R.; Tavares, P.; Bouvier, P.; Guennou, M.; Kreisel, J.; Moreira, J. Agostinho

    2014-08-01

    We report a high-pressure study of orthorhombic rare-earth manganites AMnO3 using Raman scattering (for A=Pr, Nd, Sm, Eu, Tb, and Dy) and synchrotron x-ray diffraction (XRD), for A = Pr, Sm, Eu, and Dy. In all cases, a phase transition was evidenced by the disappearance of the Raman signal at a critical pressure that depends on the A cation. For the compounds with A=Pr, Sm, and Dy, XRD confirms the presence of a corresponding structural transition to a noncubic phase, so that the disappearance of the Raman spectrum can be interpreted as an insulator-to-metal transition. We analyze the compression mechanisms at work in the different manganites via the pressure dependence of the lattice parameters, the shear strain in the ac plane, and the Raman bands associated with out-of-phase MnO6 rotations and in-plane O2 symmetric stretching modes. Our data show a crossover across the rare-earth series between two different kinds of behavior. For the smaller A cations considered in this study (Dy and Tb), the compression is nearly isotropic in the ac plane, with only small evolutions of the tilt angles and cooperative Jahn-Teller distortion. As the radius of the A cation increases, the pressure-induced reduction of Jahn-Teller distortion becomes more pronounced and increasingly significant as a compression mechanism, while the pressure-induced tilting of octahedra chains becomes conversely less pronounced. We finally discuss our results in light of the notion of chemical pressure and show that the analogy with hydrostatic pressure works quite well for manganites with the smaller A cations considered in this paper but can be misleading with large A cations.

  13. Effect of seawater immersion on plasma osmotic pressure and electrolyte balance following open chest trauma

    Institute of Scientific and Technical Information of China (English)

    李辉; 鹿尔驯; 虞积耀; 王大鹏; 马聪

    2002-01-01

    To explore the effect of seawater immersion on serum osmotic pressure and electrolytes balance following chest trauma in dogs. Methods: Twenty-five healthy adult dogs were used in the experiment. A canine model of right open pneumothorax was established by chest puncturing on all animals. Animals were divided into three groups: a control group (n = 10) with chest trauma without any immersion;a seawater group ( n = 10) immersed in seawater after chest trauma and a normal saline group ( n = 5 ) immersed in normal saline solution following chest trauma. Blood samples were taken at different time intervals to determine plasma osmotic pressure and electrolytes. The hemodynamic changes were also recorded. Results: Mortality in the seawater group was much higher than that of the control group and the normal saline group. The mean survival time in the seawater group lasted only 45 minutes, while in the control group and the normal saline group the average survival time was more than 4 hours (P < 0.01 ). One of the most important causes of death was hypernatremia and high osmolality. Severe electrolytes imbalance was observed in seawater group.Hypernatremia and high osmolality were the most significant factors of high mortality in the seawater group. Conclusions: Seawater immersion after chest trauma appears to be associated with severe electrolyte imbalance as well as high osmotic pressure, These may be the risk factors leading to fatal outcome.

  14. High pressure {mu}SR studies: rare earths and related materials

    Energy Technology Data Exchange (ETDEWEB)

    Kalvius, G.M., E-mail: kalvius@ph.tum.de; Schreier, E. [Technical University Munich, Physics Department (Germany)], E-mail: kalvius@ph.tum.de; Ekstroem, M.; Hartmann, O. [Uppsala University, Physics Department (Sweden); Henneberger, S., E-mail: kalvius@ph.tum.de; Kratzer, A. [Technical University Munich, Physics Department (Germany)], E-mail: kalvius@ph.tum.de; Waeppling, R. [Uppsala University, Physics Department (Sweden); Martin, E., E-mail: kalvius@ph.tum.de; Burghart, F.J. [Technical University Munich, Physics Department (Germany)], E-mail: kalvius@ph.tum.de; Ballou, R.; Deportes, J. [CNRS, Laboratoire Louis Neel (France); Niedermayer, Ch. [University of Constance, Faculty of Physics (Germany)

    2000-11-15

    After a short introduction to {mu}SR with respect to the study of magnetic properties, followed by a brief outline of the principle of the high pressure-low temperature {mu}SR 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 RMn{sub 2} (R = Y,Gd) to pressure. (4) The variation of magnetic parameters with pressure in La{sub 2}CuO{sub 4} (powder sample), the antiferromagnetic parent compound of the high T{sub C} superconductors of type La{sub 2-x}(Sr, Ba){sub x}CuO{sub 4}. In conclusion a short outlook on further developments is given.

  15. Magnetic ordering temperatures in rare earth metal dysprosium under ultrahigh pressures

    Science.gov (United States)

    Samudrala, Gopi K.; Tsoi, Georgiy M.; Weir, Samuel T.; Vohra, Yogesh K.

    2014-04-01

    Magnetic ordering temperatures in heavy rare earth metal dysprosium (Dy) have been studied using an ultrasensitive electrical transport measurement technique in a designer diamond anvil cell to a pressure of 69 GPa and a temperature of 10 K. Previous studies using magnetic susceptibility measurements at high pressures were able to track magnetic ordering temperature only till 7 GPa in the hexagonal close packed (hcp) phase of Dy. Our studies indicate that the magnetic ordering temperature shows an abrupt drop of 80 K at the hcp-Sm phase transition followed by a gradual decrease that continues till 17 GPa. This is followed by a rapid increase in the magnetic ordering temperatures in the double hcp phase and finally leveling off in the distorted face centered cubic phase of Dy. Our studies reaffirm that 4f-shell remains localized in Dy and there is no loss of magnetic moment or 4f-shell delocalization for pressures up to 69 GPa.

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

    Energy Technology Data Exchange (ETDEWEB)

    Stamenkovic, Vlada; Noack, Lena; Spohn, Tilman [Institute of Planetology, Westfaelische Wilhelms-Universitaet Muenster, Wilhelm-Klemm-Str. 10, 48149 Muenster (Germany); Breuer, Doris, E-mail: Vlada.Stamenkovic@dlr.de, E-mail: Lena.Noack@dlr.de, E-mail: Doris.Breuer@dlr.de, E-mail: Tilman.Spohn@dlr.de [Institute of Planetary Research, German Aerospace Center DLR, Rutherfordstrasse 2, 12489 Berlin (Germany)

    2012-03-20

    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.

  17. Earthquake Weather: Linking Seismicity to Changes in Barometric Pressure, Earth Tides, and Rainfall

    Science.gov (United States)

    West, J. D.; Garnero, E.; Shirzaei, M.

    2015-12-01

    It has been widely observed that earthquakes can be triggered due to changes in stress induced by the passage of surface waves from remote earthquakes. These stress changes are typically on the order of a few kiloPascals and occur over time spans of seconds. Less well investigated is the question of whether triggering of seismic activity can result from similar stress changes occurring over periods of hours or days due to changing barometric pressure, rainfall, and Earth tides. Past studies have shown a possible link between these stress sources and slow earthquakes in Taiwan (Hsu et al., 2015). Here, we investigate the relationship between seismicity and changing barometric pressure, Earth tides, and rainfall for four regions of the western United States where regional seismic networks provide high-quality seismic catalogs over relatively long time periods: Southern California, Northern California, the Pacific Northwest, and Utah. For each region we obtained seismic catalogs from January 2001 through September 2014 and acquired hourly data for barometric pressure and rainfall across the regions from the National Climatic Data Center. The vertical stress time series due to Earth tides was computed for the location of each weather station in the study areas. We summed the stresses from these 3 sources and looked for variations in seismicity correlated to the stress changes. We show that seismicity rates increase with increasing magnitude of stress change. In many cases the increase in seismicity is larger for reductions in vertical stress than it is for stress increases. We speculate that the dependency of seismic rate on combined vertical stress is acting through a combination of two mechanisms: (1) Reduced stresses reduce the normal force on faults, triggering failure in critically-stressed faults. (2) Increased stresses may similarly reduce the normal force on faults due to increases in pore pressure induced in the fault region.

  18. Novel Techniques for High Pressure Falling Sphere Viscosimetry under Simulated Earth's Mantle Conditions

    Science.gov (United States)

    Mueller, H. J.; Beckmann, F.; Dobson, D. P.; Hunt, S. A.; Secco, R.; Lauterjung, J.; Lathe, C.

    2014-12-01

    Viscosity data of melts measured under in situ high pressure conditions are crucial for the understanding of Earth's lower mantle and the interior of terrestrial and extrasolar Super-Earth planets. We report recent technical advances and techniques enabling falling sphere viscosity measurements in single- and double-stage DIA-type multi-anvil apparatus. For the experiments we used presses with a maximum load of 250 tons and 1750 tons. We anticipate that our system will enable viscosity measurements up to the maximum pressure for non-diamond anvils, i.e. pressures up to some 30 GPa. For the development of the new set ups the deformation of the cell assemblies were analyzed by X-ray absorption tomography at beamline W II at DESY/HASYLAB after the high pressure runs. These analysis gave considerable insights into strategies for improving the cell assembly with the result that the optimized assemblies could be used at much higher pressures without blow-outs. We think this approach is much faster and more beneficial than the classical way of trial and error. Additionally to prevent high pressure blow outs the task was to make the whole melting chamber accessible for the high pressure X-radiography system up to the maximum pressures. This way the accuracy and reliability of the measurements can be improved. For this goal we used X-ray transparent cBN-anvils at the single-stage DIA large volume press. Because this material is recently not available for the cube size of 32 mm this aproach did not work for the double-stage DIA. As a very useful and economical alternative we used slotted carbide anvils filled with fired pyrophyllite bars. To improve the frame quality of the platinum spheres taken by the CCD-camera the energy of the monochromatic X-rays had to be increased to 100 keV. The resulting ascent of scattered radiation required a new design of the X-radiography unit. Our results are demonstrated with viscosity measurements following Stokes law by evaluation of X

  19. 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.

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

    OpenAIRE

    Wajda, Douglas A.; Motl, Robert W.; Sosnoff, Jacob J.

    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 examin...

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

    Science.gov (United States)

    Napierala, C.; Lepoittevin, C.; Edely, M.; Sauques, L.; Giovanelli, F.; Laffez, P.; VanTedeloo, G.

    2010-07-01

    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 °C 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.

  2. 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.

  3. Pressure-induced valence change in the rare earth metals:The case of Praseodymium

    OpenAIRE

    Tateiwa, Naoyuki; Nakagawa, Akitoshi; Fujio, Kazuhiko; Kawae, Tatsuya; Takeda, Kazuyoshi

    2005-01-01

    The rare earth metal praseodymium (Pr) transforms from the d-fcc crystal structure (Pr-III) to {$\\alpha$}-U one (Pr-IV) at 20 GPa with a large volume collapse (${\\rm\\Delta} V/V$ = 0.16), which is associated with the valence change of the Pr ion. The two 4{\\it f} electrons in the Pr ion is supposed to be itinerant in the Pr-IV phase. In order to investigate the electronic state of the phase IV, we performed the high pressure electrical resistance measurement using the diamond anvil cell up to ...

  4. High Pressure Earth Storable Rocket Technology Program-Hipes Options 1/2 Report

    Science.gov (United States)

    Chazen, M. L.; Sicher, D.; Calvignac, J.; Ono, D.

    1999-01-01

    Under the High Pressure Earth Storable Rocket Technology (HIPES) Program, TRW successfully completed testing of two 100 lbf thrust class rhenium chambers using N204-MMH. The first chamber was successfully fired for 4789 seconds of operating time with a maximum duration of 700 seconds. This chamber had been previously fired for 5230 seconds with N2O4-N2H4. The second chamber was successfully fired for 8085 seconds with a maximum firing duration of 1200 seconds. The Isp (specific impulse) for both chambers ranged from 323 lbf-sec/lbm to 330 lbf-sec/lbm.

  5. 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.

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

    OpenAIRE

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

    2013-01-01

    Copyright @ 2013 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/3.0/). 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 pr...

  7. Lifshitz and other transitions in alkaline-earth 122 pnictides under pressure

    Science.gov (United States)

    Quader, Khandker; Widom, Michael

    2014-10-01

    We carry out T =0 first-principles total energy calculations in the entire set of alkaline 122-pnictides (A Fe2As2 ; A = alkaline-earth element Ca, Sr, Ba, Ra) as a function of hydrostatic pressure. We find multiple distinct transitions to occur, namely an enthalpic transition in which the zero-pressure striped antiferromagnetic orthorhombic (OR-AFM) phase becomes thermodynamically less stable than a competing tetragonal (T) phase, a magnetic transition in which the OR-AFM phase loses its magnetism and orthorhombicity, and a lattice parameter anomaly in which the tetragonal c-axis collapses and a collapsed tetragonal (cT) phase becomes stable. Our results for energy band dispersions and spectra, lattice parameters, enthalpies, magnetism, and elastic constants over a wide range of hydrostatic pressure provide a coherent understanding of these experimentally observed transitions. In particular, the T-cT transition and anomalies in lattice parameters and elastic properties, observed at finite temperatures, are interpreted as arising from proximity to T =0 Lifshitz transitions, wherein pressure causes nontrivial changes in the Fermi surface topology in these materials.

  8. Evolution of the Oxidation State of the Earth's Mantle: Challenges of High Pressure Quenching

    Science.gov (United States)

    Danielson, L. R.; Righter, K.; Keller, L. P.; Rahman, Z.

    2015-12-01

    The oxidation state of the Earth's mantle during formation remains an unresolved question, whether it was constant throughout planetary accretion [1], transitioned from reduced to oxidized [2,3,4], or from oxidized to reduced [1,5]. We investigate the stability of Fe3+ at depth, in order to constrain processes (water, late accretion, dissociation of FeO) which may reduce or oxidize the Earth's mantle. Experiments of more mafic compositions and at higher pressures commonly form a polyphase quench intergrowth composed primarily of pyroxenes, with interstitial glass which hosts nearly all of the more volatile minor elements. In our previous experiments on shergottite compositions, variable fO2, T, and P <4 GPa, Fe3+/ΣFe decreased slightly with increasing P, similar to terrestrial basalt [6,7,8]. For oxidizing experiments < 7GPa, Fe3+/ΣFe decreased as well [9], but it's unclear from previous modelling whether the deeper mantle could retain significant Fe3+ [1,10]. Our current experiments expand our pressure range deeper into the Earth's mantle and focus on compositions and conditions relevant to the early Earth. Experiments with Knippa basalt as the starting composition were conducted at 1-8 GPa and 1800 °C, using a molybdenum capsule to set the fO2 near IW, by buffering with Mo-MoO3. TEM and EELS analyses revealed the run products from 7-8 GPa quenched to polycrystalline phases, with the major phase pyroxene containing approximately equal Fe3+/2+. A number of different approaches have been employed to produce glassy samples that can be measured by EELS and XANES. A more intermediate andesite was used in one experiment, and decompression during quenching was attempted after [11], but both resulted in a finer grained polyphase texture. Experiments are currently underway to test how different capsule materials may affect quench texture. A preliminary experiment using liquid nitrogen to greatly enhance the rate of cooling of the assembly has also been attempted and

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

    International Nuclear Information System (INIS)

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

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

    DEFF Research Database (Denmark)

    Krogsbøll, Anette Susanne; Fuglsang, Leif D

    level. The Finite element program PLAXIS is used and two material models are evaluated, the Mohr-Coulomb model and the Hardening Soil model. The differences between the two concern the deformation properties. Generally good agreement was observed between physical and numerical models. The HS-model......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...... showed the right behaviour in pre-failure as well as failure for both flexible and stiff walls, whereas the MC-model showed some shortcomings when stiff walls were modelled....

  11. Simplification of heating systems by omitting circulating pumps and differential pressure regulating valves. Balancing; Vereinfachung durch Einsparung von Umwaelzpumpen und Differenzdruckregler. Hydraulischer Abgleich

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-07-01

    Balancing of heating systems today is possible without differential pressure regulating valves. Only the design basis volume flow is adjusted at the sectioning valve of the heating section, while the part-load behaviour is regulated accurately via thermal power regulation. This simplifies balancing, and the total efficiency of systems will be better than with the commonly used differential pressure regulating valves.

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

    Directory of Open Access Journals (Sweden)

    Clara Sanz Morère

    2016-01-01

    Full Text Available 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. Sensors with improved sensing techniques can be applied to a variety of research problems: diagnosing limb problems, footwear design, or injury prevention. This paper reviews commercially available sensors used in foot plantar pressure measurements and proposes the utilization of pressure sensors based on the MEMS (microelectromechanical systems technique. Pressure sensors based on this technique have the capacity to measure pressure with high accuracy and linearity up to high pressure levels. Moreover, being small in size, they are highly suitable for this type of measurement. We present two MEMS sensor models and study their suitability for the intended purpose by performing several experiments. Preliminary results indicate that the sensors are indeed suitable for measuring foot plantar pressure. Importantly, by measuring pressure continuously, they can also be utilized for body balance measurements.

  13. 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.

  14. Three-dimensional numerical simulation and earth pressure analysis on double-row piles with consideration of spatial effects

    Institute of Scientific and Technical Information of China (English)

    Zi-han WANG; Jian ZHOU

    2011-01-01

    As a new kind of technology in retaining structures,the characteristics of double-row piles are significantly affected by spatial effects.In this paper,double-row piles as a retaining structure are simulated numerically in three-dimension by finite element software PLAXIS 3D FOUNDATION.The behavior differences of piles in different positions around the foundation pit are analyzed.By changing the parameters,including the length-width ratio,the excavation depth,the distance between rows and the diameter of piles,the variations of the lateral deformation,the bending moment and the earth pressure around the piles are determined.The reasonable values of parameters and some suggestions with consideration of earth pressure are proposed for the design of double-row piles as a retaining structure.The results show that the lateral deformation and bending moment are the largest in the middle of long side of the foundation pit,which is identified as the most unfavorable position.It is indicated that the earth pressure between rows above pit bottom is close to active earth pressure,while the earth pressure between rows under pit bottom is close to static earth pressure.It is suggested that 1/2-2/3 of pile length,0.6-1.2 m,3d-6d,and 2d-2.5d be chosen as embedded depth of piles,diameter of piles,distance between rows,and distance between piles,respectively,where d is the pile diameter.

  15. 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.

    2016-09-01

    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.

  16. The high-pressure phase of alumina and implications for Earth's D″ layer

    Science.gov (United States)

    Oganov, Artem R.; Ono, Shigeaki

    2005-01-01

    Using ab initio simulations and high-pressure experiments in a diamond anvil cell, we show that alumina (Al2O3) adopts the CaIrO3-type structure above 130 GPa. This finding substantially changes the picture of high-pressure behavior of alumina; in particular, we find that perovskite structure is never stable for Al2O3 at zero Kelvin. The CaIrO3-type phase suggests a reinterpretation of previous shock-wave experiments and has important implications for the use of alumina as a window material in shock-wave experiments. In particular, the conditions of the stability of this phase correspond to those at which shock-wave experiments indicated an increase of the electrical conductivity. If this increase is caused by high ionic mobility in the CaIrO3-type phase of Al2O3, similar effect can be expected in the isostructural postperovskite phase of MgSiO3 (which is the dominant mineral phase in the Earth's D″ layer). The effect of the incorporation of Al on the perovskite/postperovskite transition of MgSiO3 is discussed. PMID:16040809

  17. 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.

  18. 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.

  19. 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. PMID:27134578

  20. Miniaturization techniques for obtaining static pressures comparable to the pressure at the center of the earth: X-ray diffraction at 416 GPa

    International Nuclear Information System (INIS)

    X-ray diffraction studies on tungsten and molybdenum were performed, using a 4-μm-diam x-ray beam, to very high pressures, with the pressures being obtained from the measured lattice parameters and isothermal equations of state of tungsten and molybdenum deduced from shock data. The bcc structure persists to the highest pressure, 378 GPa in tungsten, and 416 GPa in molybdenum. The static pressures generated and measured here exceed the pressure of 361 GPa at the center of the earth, the first time that this has been achieved and measured with a calibrated pressure scale. The details of the pressure profile at 335 GPa are shown and are of great use in designing anvils for future research. It is noted that the maximum pressures attained by x-ray diffraction with beveled anvils varies linearly with D-1/2 where D is the diameter of the flat suggesting that, perhaps, even higher pressures are possible with further miniaturization. A scaling law is used to calculate the minimum correction due to the presence of nonhydrostatic stress

  1. 力平衡法测量大气压强%Atmospheric pressure measurement based on force balance principle

    Institute of Scientific and Technical Information of China (English)

    钟寿仙; 杨自强; 任团结; 夏亚康; 胡家晨; 林春丹

    2014-01-01

    依据力平衡法原理,重新构思、设计了测量大气压强的实验方案及装置,力学传感器的使用,提高了大气压强测量中的关键物理量的测量精度;采用最小二乘法,实现了大气压强的巧妙测量。%Based on the force balance principle ,the experimental scheme and apparatus were rede-signed to measure the atmospheric pressure .By using mechanical sensor and least square method ,the atmospheric pressure had been measured ingeniously ,and the measurement accuracies of atmospheric pressure and the relevant key physical quantities were improved .

  2. Discovery of earth-abundant nitride semiconductors by computational screening and high-pressure synthesis

    Science.gov (United States)

    Hinuma, Yoyo; Hatakeyama, Taisuke; Kumagai, Yu; Burton, Lee A.; Sato, Hikaru; Muraba, Yoshinori; Iimura, Soshi; Hiramatsu, Hidenori; Tanaka, Isao; Hosono, Hideo; Oba, Fumiyasu

    2016-01-01

    Nitride semiconductors are attractive because they can be environmentally benign, comprised of abundant elements and possess favourable electronic properties. However, those currently commercialized are mostly limited to gallium nitride and its alloys, despite the rich composition space of nitrides. Here we report the screening of ternary zinc nitride semiconductors using first-principles calculations of electronic structure, stability and dopability. This approach identifies as-yet-unreported CaZn2N2 that has earth-abundant components, smaller carrier effective masses than gallium nitride and a tunable direct bandgap suited for light emission and harvesting. High-pressure synthesis realizes this phase, verifying the predicted crystal structure and band-edge red photoluminescence. In total, we propose 21 promising systems, including Ca2ZnN2, Ba2ZnN2 and Zn2PN3, which have not been reported as semiconductors previously. Given the variety in bandgaps of the identified compounds, the present study expands the potential suitability of nitride semiconductors for a broader range of electronic, optoelectronic and photovoltaic applications. PMID:27325228

  3. Analysis on Earth Conveying and Pressure Maintaining of Screw Conveyors of EPB Shields%土压平衡盾构螺旋输送机排土及保压作用分析

    Institute of Scientific and Technical Information of China (English)

    周冠南

    2012-01-01

    The earth conveying and pressure maintaining of screw conveyors play an important role in the safe and effi- cient boring of EPB shields. The working principles and influencing factors of the earth conveying and pressure maintai- ning of screw conveyors are systematically analyzed. Conclusions drawn are as follows : 1 ) The earth pressure balance in the boring of EPB shields includes the pressure balance between inside chamber and outside chamber, the pressure bal- ance inside the screw conveyor, and the earth input/output volume balance, which can be realized by controlling the volume of earth conveyed. 2) When the earth enters the screw conveyors, the water/soil pressure in the chamber is re- sisted by the gravity of the earth and the friction with the screw rod, lamina and the inner side of the conveyor, so as to keep stable earth conveying. 3 ) The earth behavior, which has great influence on the earth conveying and pressure maintaining of screw conveyors, can be improved by injecting ground conditioning agents into areas ahead of the cutter heads and into the chamber. 4) Regarding the structure of the screw conveyor, the pressure maintaining effect can be improved by means of reducing the pitch, adopting discontinuous screw and double screw conveyors.%螺旋输送机的排土和保压作用的发挥对土压平衡盾构的施工安全与效率有重要影响,对其作用机制及影响其作用发挥的因素进行系统的理论分析,并参考工程实测数据,得出以下结论:1)盾构施工中的土压平衡包括土仓内外与螺旋输送机内的压力平衡和进、出土量的平衡,其通过螺旋输送机排土量的控制来实现;2)渣土进入螺旋输送机后,依靠自身重力及与螺杆、叶片和筒壁界面间的摩擦作用来抵抗土仓内的水土压力,保持出渣过程的稳定性;3)渣土性质对螺旋输送机的排土和保压效果有较大影响,主要通过向刀盘前方和土仓内添加改良材料的

  4. 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

  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. 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.

  7. 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

  8. 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

  9. Energy balance in the solar transition region. II - Effects of pressure and energy input on hydrostatic models

    Science.gov (United States)

    Fontenla, J. M.; Avrett, E. H.; Loeser, R.

    1991-01-01

    The radiation of energy by hydrogen lines and continua in hydrostatic energy-balance models of the transition region between the solar chromosphere and corona is studied using models which assume that mechanical or magnetic energy is dissipated in the hot corona and is then transported toward the chromosphere down the steep temperature gradient of the transition region. These models explain the average quiet sun and also the entire range of variability of the Ly-alpha lines. The relations between the downward energy flux, the pressure of the transition region, and the different hydrogen emission are described.

  10. Resource constrained flux balance analysis predicts selective pressure on the global structure of metabolic networks

    OpenAIRE

    Abedpour, Nima; Kollmann, Markus

    2015-01-01

    Background A universal feature of metabolic networks is their hourglass or bow-tie structure on cellular level. This architecture reflects the conversion of multiple input nutrients into multiple biomass components via a small set of precursor metabolites. However, it is yet unclear to what extent this structural feature is the result of natural selection. Results We extend flux balance analysis to account for limited cellular resources. Using this model, optimal structure of metabolic networ...

  11. Development of the Kawai-type Multi-anvil Apparatus (KMA) and Its Application to High Pressure Earth Science

    International Nuclear Information System (INIS)

    Since Birch's prediction on the structure of the Earth's interior high pressure Earth science has rapidly been grown by the Kawai-type multi-anvil apparatus (KMA) and the diamond anvil cell (DAC). An important advantage of the KMA is its large specimen volume which makes it possible to conduct experiments under precisely controlled P-T conditions. A typical application of the KMA to the Earth science might be determination of the post-spinel phase equilibria in the system Mg2SiO4-Fe2SiO4. By adopting sintered diamond (SD) as the anvil material accessible pressure of the KMA has substantially increased. Melting experiments of mantle materials up to 35 GPa opened a new paradigm on the mantle fractionation in early Earth. Combining the KMA equipped with SD anvils with the synchrotron radiation phase equilibria of Fe GaN and Fe2O3 were determined by means of in situ X-ray diffraction. Special attention was paid to define the phase boundaries between perovskite and post-perovskite in MgGeO3 and MnGeO3 as analogues of MgSiO3. We also observed the spin transition of Fe2+ in (Mg0.87Fe0.17)O at 300 and 700 K. Recently the maximum attainable pressure is reaching 100 GPa and high P-T experiments up to 90 GPa are our ordinary jobs. In order to produce still higher pressure however innovation of SD such as NPD is indispensable.

  12. Stress State of Elastic Thick-Walled Ring With Self-Balanced Pressures Distributed on Its Internal and External Borders

    Directory of Open Access Journals (Sweden)

    Kravchuk Aleksandr Stepanovich

    2015-10-01

    Full Text Available For the first time with the help of the theory of analytic functions and Kolosov-Muskhelishvili formulas the problem of the two-dimensional theory of elasticity for a thickwalled ring with the uneven pressures, acting on its borders, was solved. The pressure on the inner and outer boundaries is represented by Fourier series. The authors represent the two complex functions which solve boundary problem in the form of Laurent series. The logarithmic terms in these series are absent because the boundary problem has the self-balancing loads on each boundary of ring. The coefficients in the Laurent series are calculated by the boundary conditions. Firstly, the equations were obtained in the general form. But the hypothesis about even distributions of pressures at borders of ring was used for constructing an example. It leads to the fact that all coefficients of analytic functions represented in Laurent series have to be only real. As a solving example, the representation of pressures in equivalent hypotrochoids was used. The application of the computer algebra system Mathematica greatly simplifies the calculation of the distribution of stresses and displacements in ring. It does not require manual formal separation of real and imaginary parts in terms of Kolosov-Muskhelishvili to display the distribution of the physical parameters. It separates them only for calculated numbers with the help of built-in functions.

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

    Science.gov (United States)

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

    2013-01-01

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

  14. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-12-15

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

  16. High pressure effects on the superconductivity in rare-earth-doped CaFe2As2

    Science.gov (United States)

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

    2014-01-01

    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 the 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 as high as ∼51 K at 1.9 GPa, presenting the highest Tc reported in the intermetallic class of 122 iron-based superconductors. The resistive transition observed suggests a possible existence of two superconducting phases at low pressures of 0.5 GPa: one phase starting at Tc1 ∼ 48 K and the other starts at Tc2 ∼ 16 K. The two superconducting transitions show distinct variations with increasing pressure. High pressure and low-temperature structural studies indicate that the superconducting phase is a collapsed tetragonal ThCr2Si2-type (122) crystal structure.

  17. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Sideridis, A. [Laboratory of Fluid Mechanics and Turbomachinery, Department of Mechanical Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Yakinthos, K., E-mail: kyros@eng.auth.g [Laboratory of Fluid Mechanics and Turbomachinery, Department of Mechanical Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Goulas, A. [Laboratory of Fluid Mechanics and Turbomachinery, Department of Mechanical Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)

    2011-02-15

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

  19. The temperature structure and pressure balance of magnetic loops in active regions. [in solar atmosphere

    Science.gov (United States)

    Foukal, P.

    1975-01-01

    EUV observations show many active region loops in lines formed at temperatures between 10,000 and 2,000,000 K. The brightest loops are associated with flux tubes leading to the umbrae of sunspots. It is shown that the high visibility of certain loops in transition region lines is due principally to a sharp radial decrease of temperature to chromospheric values toward the loop axis. The plasma density of these cool loops is not significantly greater than in the hot gas immediately surrounding it. Consequently, the internal gas pressure of the cool material is clearly lower. The hot material immediately surrounding the cool loops is generally denser than the external corona by a factor 3-4. When the active region is examined in coronal lines, this hot high pressure plasma shows up as loops that are generally parallel to the cool loops but significantly displaced laterally.

  20. 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.

  1. 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.

  2. Earth's air pressure 2.7 billion years ago constrained to less than half of modern levels

    Science.gov (United States)

    Som, Sanjoy M.; Buick, Roger; Hagadorn, James W.; Blake, Tim S.; Perreault, John M.; Harnmeijer, Jelte P.; Catling, David C.

    2016-06-01

    How the Earth stayed warm several billion years ago when the Sun was considerably fainter is the long-standing problem of the `faint young Sun paradox'. Because of negligible O2 and only moderate CO2 levels in the Archaean atmosphere, methane has been invoked as an auxiliary greenhouse gas. Alternatively, pressure broadening in a thicker atmosphere with a N2 partial pressure around 1.6-2.4 bar could have enhanced the greenhouse effect. But fossilized raindrop imprints indicate that air pressure 2.7 billion years ago (Gyr) was below twice modern levels and probably below 1.1 bar, precluding such pressure enhancement. This result is supported by nitrogen and argon isotope studies of fluid inclusions in 3.0-3.5 Gyr rocks. Here, we calculate absolute Archaean barometric pressure using the size distribution of gas bubbles in basaltic lava flows that solidified at sea level ~2.7 Gyr in the Pilbara Craton, Australia. Our data indicate a surprisingly low surface atmospheric pressure of Patm = 0.23 +/- 0.23 (2σ) bar, and combined with previous studies suggests ~0.5 bar as an upper limit to late Archaean Patm. The result implies that the thin atmosphere was rich in auxiliary greenhouse gases and that Patm fluctuated over geologic time to a previously unrecognized extent.

  3. 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.

  4. 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

  5. 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...

  6. Contrasting effects of vasodilators on blood pressure and sodium balance in the hypertension of autonomic failure

    Science.gov (United States)

    Jordan, J.; Shannon, J. R.; Pohar, B.; Paranjape, S. Y.; Robertson, D.; Robertson, R. M.; Biaggioni, I.

    1999-01-01

    Supine hypertension, which is very common in patients with autonomic failure, limits the use of pressor agents and induces nighttime natriuresis. In 13 patients with severe orthostatic hypotension due to autonomic failure (7 women, 6 men, 72 +/- 3 yr) and supine hypertension, the effect of 30 mg nifedipine (n = 10) and 0.025 to 0.2 mg/h nitroglycerin patch (n = 11) on supine BP, renal sodium handling, and orthostatic tolerance was determined. Medications were given at 8 p.m.; patients stood up at 8 a.m. Nitroglycerin was removed at 6 a.m. Compared with placebo, nifedipine and nitroglycerin decreased systolic BP during the night by a maximum of 37 +/- 9 and 36 +/- 10 mmHg, respectively (P hypertension in patients with autonomic failure. However, nifedipine has a prolonged depressor effect and worsens orthostatic hypotension in the morning. The decrease in pressure natriuresis that would be expected with the substantial decrease in BP obtained with nitroglycerin and nifedipine may be offset by a direct effect of both drugs on renal sodium handling.

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

    International Nuclear Information System (INIS)

    Recently, small-scale pressure-balanced structures (PBSs) were identified in the solar wind, but their formation mechanism remains unclear. This work aims to reveal the dependence of the properties of small-scale PBSs on the background magnetic field (B0) direction and thus to corroborate the in situ mechanism that forms them. We analyze the plasma and magnetic field data obtained by WIND in the quiet solar wind at 1 AU. First, we use a developed moving-average method to obtain B0(s, t) for every temporal scale (s) at each time moment (t). By wavelet cross-coherence analysis, we obtain the correlation coefficients between the thermal pressure Pth and the magnetic pressure PB, distributing against the temporal scale and the angle θxB between B0(s, t) and Geocentric Solar Ecliptic coordinates (GSE)-x. We note that the angle coverage of a PBS decreases with shorter temporal scale, but the occurrence of the PBSs is independent of θxB. Suspecting that the isolated small PBSs are formed by compressive waves in situ, we continue this study by testing the wave modes forming a small-scale PBS with B0(s, t) quasi-parallel to GSE-x. As a result, we identify that the cross-helicity and the compressibility attain values for a slow mode from theoretical calculations. The wave vector is derived from minimum variance analysis. Besides, the proton temperatures obey T ∥ derived from the velocity distribution functions, excluding a mirror mode, which is the other candidate for the formation of PBSs in situ. Thus, a small-scale PBS is shown to be driven by oblique, slow-mode waves in the solar wind

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-09-01

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

  9. MODIFIED ACTIVE STATE EARTH PRESSURE ROTATING AROUND WALL TOE%改进的绕墙趾转动主动状态土压力

    Institute of Scientific and Technical Information of China (English)

    王仕传; 张平均; 李云凤; 邵艳

    2015-01-01

    墙背土压力分布与挡土墙的位移大小、位移模式以及平衡状态密切相关. 针对绕墙底向外转动的刚性挡土墙,基于已有的土压力计算理论,结合由卸荷路径三轴试验所建立的填土内摩擦角与挡土墙位移间的关系,提出一种改进的考虑位移影响的主动状态土压力计算方法. 分析表明:随着挡土墙位移的发展,墙背土压力由静止土压力逐步减小,当挡土墙位移达到临界值后,相应的墙背土压力均收敛到库仑主动土压力. 填土内摩擦角发挥值的分布显著影响墙背土压力分布. 非极限平衡状态时,墙背土压力大于库仑主动土压力.%Distribution of earth pressure behind retaining wall is closely related with wall displacement value, movement mode, and equilibrium condition.For rigid retaining wall rotating outward around base, based on existing earth pressure theory and relationship between internal friction angle of backfill and wall displacement resulted from triaxial test of unloading path, a modified computational method of active state earth pressure considering wall displacement was set up.Analysis showed that earth pressure behind retaining wall decreased gradually from at-rest earth pressure as the development of wall displacement, and, when wall displacement reached critical value, all corresponding earth pressure values behind the wall converged to Coulomb active earth pressure values.Distribution of earth pressure behind retaining wall was significantly influenced by the distribution of expression internal friction angle of backfill.Active state earth pressure of non-limit equilibrium condition was larger than Coulomb active earth pressure.

  10. 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.

  11. The high-pressure phase of alumina and implications for Earth's D″ layer

    OpenAIRE

    Artem R. Oganov; Ono, Shigeaki

    2005-01-01

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

  12. 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

  13. 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

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

    Science.gov (United States)

    Reddy, Vanteru M.; Rahman, Mustafa M.; Gandi, Appala N.; Elbaz, Ayman M.; Schrecengost, Robert A.; Roberts, William L.

    2016-01-01

    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

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

    Science.gov (United States)

    Jassowski, D. M.

    1997-01-01

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

  16. 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

  17. 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

  18. Windsock memory COnditioned RAM (CO-RAM) pressure effect: Forced reconnection in the Earth's magnetotail

    Science.gov (United States)

    Vörös, Z.; Facskó, G.; Khodachenko, M.; Honkonen, I.; Janhunen, P.; Palmroth, M.

    2014-08-01

    Magnetic reconnection (MR) is a key physical concept explaining the addition of magnetic flux to the magnetotail and closed flux lines back-motion to the dayside magnetosphere. This scenario elaborated by Dungey (1963) can explain many aspects of solar wind-magnetosphere interaction processes, including substorms. However, neither the Dungey model nor its numerous modifications were able to explain fully the onset conditions for MR in the tail. In this paper, we introduce new onset conditions for forced MR in the tail. We call our scenario the "windsock memory conditioned ram pressure effect." Our nonflux transfer-associated forcing is introduced by a combination of the large-scale windsock motions exhibiting memory effects and solar wind dynamic pressure actions on the nightside magnetopause during northward oriented interplanetary magnetic field (IMF). Using global MHD Grand Unified Magnetosphere Ionosphere Coupling Simulation version 4 simulation results, upstream data from Wind, magnetosheath data from Cluster 1 and distant tail data from the two-probe Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon's Interaction with the Sun mission, we show that the simultaneous occurrence of vertical windsock motions of the magnetotail and enhanced solar wind dynamic pressure introduces strong nightside disturbances, including enhanced electric fields and persistent vertical cross-tail shear flows. These perturbations, associated with a stream interaction region in the solar wind, drive MR in the tail during episodes of northward oriented interplanetary magnetic field (IMF). We detect MR indirectly, observing plasmoids in the tail and ground-based signatures of earthward moving fast flows. We also consider the application to solar system planets and close-in exoplanets, where the proposed scenario can elucidate some new aspects of solar/stellar wind-magnetosphere interactions.

  19. [Research on Adaptive Balance Reaction for Gait Slippery Instability Events on Level Walk Based on Plantar Pressure and Gait Parameter Analysis].

    Science.gov (United States)

    Li, Yang; Zhang, Junxia; Si, Ying

    2015-12-01

    Nowadays, for gait instability phenomenon, many researches have been carried out at home and abroad. However, the relationship between plantar pressure and gait parameters in the process of balance adjustment is still unclear. This study describes the human body adaptive balance reaction during slip events on slippery level walk by plantar pressure and gait analysis. Ten healthy male subjects walked on a level path wearing shoes with two contrastive contaminants (dry, oil). The study collected and analyzed the change rule of spatiotemporal parameters, plantar pressure parameters, vertical ground reaction force (VGRF), etc. The results showed that the human body adaptive balance reaction during slip events on slippery level walk mainly included lighter touch at the heel strikes, tighter grip at the toe offs, a lower velocity, a shorter stride length and longer support time. These changes are used to maintain or recover body balance. These results would be able to explore new ideas and provide reference value for slip injury prevention, walking rehabilitation training design, research and development of walking assistive equipments, etc. PMID:27079090

  20. Windsock memory conditioned RAM (Co-Ram) pressure effect: forced reconnection in the Earth's magnetotail

    CERN Document Server

    Vörös, Z; Khodachenko, M; Honkonen, I; Janhunen, P; Palmroth, M

    2014-01-01

    Magnetic reconnection (MR) is a key physical concept explaining the addition of magnetic flux to the magnetotail and closed flux lines back-motion to the dayside magnetosphere. This scenario elaborated by \\citet{dung63}, can explain many aspects of solar wind-magnetosphere interaction processes, including substorms. However, neither the Dungey model nor its numerous modifications were able to explain fully the onset conditions for MR in the tail. In this paper, we introduce new onset conditions for forced MR in the tail. We call our scenario the "windsock memory conditioned ram pressure effect". Our non-flux-transfer associated forcing is introduced by a combination of large-scale windsock motions exhibiting memory effects and solar wind dynamic pressure actions on the nightside magnetopause during northward oriented IMF. Using global MHD GUMICS-4 simulation results, upstream data from WIND, magnetosheath data from Cluster-1 and distant-tail data from the two-probe ARTEMIS mission, we show that the simultaneo...

  1. Comparison of Regression Methods to Compute Atmospheric Pressure and Earth Tidal Coefficients in Water Level Associated with Wenchuan Earthquake of 12 May 2008

    Science.gov (United States)

    He, Anhua; Singh, Ramesh P.; Sun, Zhaohua; Ye, Qing; Zhao, Gang

    2016-07-01

    The earth tide, atmospheric pressure, precipitation and earthquake fluctuations, especially earthquake greatly impacts water well levels, thus anomalous co-seismic changes in ground water levels have been observed. In this paper, we have used four different models, simple linear regression (SLR), multiple linear regression (MLR), principal component analysis (PCA) and partial least squares (PLS) to compute the atmospheric pressure and earth tidal effects on water level. Furthermore, we have used the Akaike information criterion (AIC) to study the performance of various models. Based on the lowest AIC and sum of squares for error values, the best estimate of the effects of atmospheric pressure and earth tide on water level is found using the MLR model. However, MLR model does not provide multicollinearity between inputs, as a result the atmospheric pressure and earth tidal response coefficients fail to reflect the mechanisms associated with the groundwater level fluctuations. On the premise of solving serious multicollinearity of inputs, PLS model shows the minimum AIC value. The atmospheric pressure and earth tidal response coefficients show close response with the observation using PLS model. The atmospheric pressure and the earth tidal response coefficients are found to be sensitive to the stress-strain state using the observed data for the period 1 April-8 June 2008 of Chuan 03# well. The transient enhancement of porosity of rock mass around Chuan 03# well associated with the Wenchuan earthquake (Mw = 7.9 of 12 May 2008) that has taken its original pre-seismic level after 13 days indicates that the co-seismic sharp rise of water well could be induced by static stress change, rather than development of new fractures.

  2. 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

    2016-01-01

    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

  3. 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.

  4. 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.

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

    Science.gov (United States)

    North, Matthew; Petropoulos, George

    2014-05-01

    Soil Vegetation Atmosphere Transfer (SVAT) models are becoming the preferred scientific tool to assess land surface energy fluxes due to their computational efficiency, accuracy and ability to provide results at fine temporal scales. An all-inclusive validation of those models is a fundamental step before those can be confidently used for any practical application or research purpose alike. SimSphere is an example of a SVAT model, simulating a large array of parameters characterising various land surface interactions over a 24 hour cycle at a 1-D vertical profile. Being able to appreciate the uncertainty of SimSphere predictions, is of vital importance towards increasing confidence in the models' overall use and ability to represent accurate land surface interactions. This is particularly important, given that its use either as a stand-alone tool or synergistically with Earth Observation (EO) data is currently expanding worldwide. In the present study, uncertainty in the SimSphere's predictions is evaluated at seven European sites, representative of a range of ecosystem conditions and biomes types for which in-situ data from the CarboEurope IP operational network acquired during 2011 were available. Selected sites are characterised by varying topographical characteristics, which further allow developing a comprehensive understanding on how topography can affect the models' ability to reproduce the variables which are evaluated. Model simulations are compared to in-situ data collected on cloud free days and on days with high Energy Balance Ratio. We focused here specifically on evaluating SimSphere capability in predicting selected variables of the energy balance, namely the Latent Heat (LE), Sensible heat (H) and Net Radiation (Rn) fluxes. An evaluation of the uncertainty in the model predictions was evaluated on the basis of extensive statistical analysis that was carried out by computing a series of relevant statistical measures. Results obtained confirmed the

  6. Detection of Yarkovsky effect and solar radiation pressure on Near-Earth Asteroids

    Science.gov (United States)

    Faggioli, Laura; Del Vigna, Alessio; Milani, Andrea; Spoto, Federica; Valsecchi, Giovanni B.

    2016-10-01

    The orbit of small-sized asteroids can be affected by non-gravitational perturbations. When this happens, non-gravitational forces need to be taken into account since they are as important as collisions and gravitational perturbations for the overall understanding of the asteroid orbital evolution.The Yarkovsky effect and the Solar Radiation Pressure (SRP) are non-gravitational perturbations that can be modelled knowing the physical properties of asteroids, and whose consequences of the motions can be measured from accurate astrometry.The knowledge of the physical properties of asteroids is usually not sufficient to produce the thermophysical models needed for the computation of the Yarkovsky acceleration. Nevertheless, it can often be measured as a semimajor axis drift if the astrometric dataset contains extremely accurate observations (e.g. radar data), or if the observations span a sufficiently long time interval.Farnocchia et al. 2013 list 21 NEAs with a measurable semimajor-axis drift. Since 2013, the number of asteroids for which it is possible to detect the Yarkovsky effect has grown. This is due to the increased quality and time span of the observations, and to new radar measurements that have since become available. We are able to detect the Yarkovsky effect for more than 40 NEAs, employing a high precision dynamical model, including the Newtonian attraction of 16 massive asteroids and the planetary relativistic terms, and a suitable astrometric data treatment. We present a list of objects with a significant detection of Yarkovksy effect and a value compatible with the Yarkovsky mechanism.The computed non-gravitational perturbations will be added to the web portal of the ESA SSA-NEO Coordination Centre, highlighting the fact that the orbit has been computed taking the Yarkovsky effect or the SRP into account. The inclusion of non-gravitational perturbations can also affect the results of the impact monitoring, as in the case of (410777) 2009 FD, (29075

  7. 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.

  8. High-Pressure Rare Earth Disilicates REE2Si 2O 7( REE=Nd, Sm, Eu, Gd): Type K

    Science.gov (United States)

    Fleet, Michael E.; Liu, Xiaoyang

    2001-10-01

    A new structure type (K) is reported for the disilicates of Nd, Sm, Eu, and Gd made at high pressure. Crystals of type K were synthesized at 10 GPa, 1600-1700°C in an MA6/8 superpress and used for single-crystal X-ray structure study by Kappa CCD diffractometry at room temperature. Crystal data are: monoclinic, space group P21/n, Z=4; Nd2Si2O7-a=6.6658(2), b=6.7234(3), c=12.3975(6) Å, β=102.147(3)°, V=543.2 Å3, R=0.029, and Dx=5.584 g/cm3; Sm2Si2O7-a=6.6039(3), b=6.6849(3), c=12.3069(5) Å, β=102.489(3)°, V=530.4 Å3, R=0.038, and Dx=5.871 g/cm3; Eu2Si2O7-a=6.5777(3), b=6.6652(4), c=12.2668(8) Å, β=102.671(4)°, V=524.7 Å3, R=0.030, and Dx=5.976 g/cm3; Gd2Si2O7-a=6.5558(4), b=6.6469(4), c=12.2394(6) Å, β=102.844(3)°, V=520.0 Å3, R=0.026, and Dx=6.166 g/cm3. The type K structure is built from a diorthosilicate group [Si2O7] interconnected by REE3+ cations in eightfold coordination with oxygen. The bridging oxygen (Si-O-Si) bond angle of the diorthosilicate group of rare earth disilicates stable at 1 bar (types A to G) is related to spatial accommodation of the REE3+ cation and ranges from 130 to 135° in the light rare earth disilicates (types A, F, G) to 180° in Lu2Si2O7 (type C). Volume reduction in the high-pressure type K structure is achieved largely by closure of the Si-O-Si bond angle to 122.7-124.4°, through rigid body rotation of the two SiO4 tetrahedra. This also permits a marginal increase in the average coordination of the REE3+ cation.

  9. 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 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.

  10. Discover Earth

    Science.gov (United States)

    Steele, Colleen

    1998-01-01

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

  11. 超大直径泥水平衡盾构施工时建筑物保护技术研究%Study of Protecting Structure during Super-Diameter Slurry-Pressure Balanced Tunnel Boring Machine Work

    Institute of Scientific and Technical Information of China (English)

    李章林

    2011-01-01

    The mechanism of earth subsidence during SPB-TBM construction is analysed, combined with the case of super diameter Slurry-Pressure Balanced Tunnel Boring Machine (SPB-TBM) work. Then, the technique for controlling subside nee of the structure when the super diameter SPB-TBM passes across underneath is studied from the aspects such as slurry pressure, slurry parameter and so on. In the end, by rational setting the pressure of shield cutting, high density of slurry circulation, pressure- quantity-controlling grouting model, the subsidence of the structure can be decreased, as well as inhomogeneous subsidence ratio can fit the bill.%通过分析泥水平衡盾构施工引起地表沉降的机理,并结合超大直径泥水平衡盾构施工实例,从切口压力、泥水指标控制及同步注浆管理等方面探讨超大直径泥水平衡盾构施工建筑物沉降的控制技术.结果表明,通过合理的设定盾构推进切口压力,重浆循环模式,采用“双控”同步注浆模式,有效地控制了建筑物沉降,并且房屋不均匀沉降系数满足房屋保护要求.

  12. Novel high-pressure structures of MgCO3, CaCO3 and CO2 and their role in Earth's lower mantle

    Science.gov (United States)

    Oganov, Artem R.; Ono, Shigeaki; Ma, Yanming; Glass, Colin W.; Garcia, Alberto

    2008-08-01

    Most of the oxidized carbon in the Earth's lower mantle is believed to be stored in the high-pressure forms of MgCO3 and/or CaCO3 or possibly even CO2. Recently, through ab initio evolutionary simulations and high-pressure experiments, a complete picture of phase transformations of CaCO3 at mantle pressures was obtained. Here, using the same approach, we investigate the high-pressure structures of MgCO3. Two new structure types were predicted to be stable in the relevant pressure range: one at 82-138 GPa and the other above 138 GPa. Both phases contain rings of corner-sharing CO4-tetrahedra. These predictions were largely confirmed by the experiments presented here. A number of structurally very different, but energetically competitive metastable polymorphs were found and reveal complex high-pressure chemistry of MgCO3, in contrast to CaCO3. For CO2, from 19 GPa to at least 150 GPa, we find β-cristobalite structure to be stable. Differences between high-pressure tetrahedral carbonates and low-pressure silicates are discussed in terms of rigidity of the T-O-T angles (flexible when T = Si and stiff when T = C). We show that through most of the P-T conditions of the mantle, MgCO3 is the major host of oxidized carbon in the Earth. We discuss the possibility of CO2 release at the very bottom of the mantle, which could enhance partial melting of rocks and explain the geodynamical differences between the Earth and Venus.

  13. 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)

  14. In situ XFEL measurement system for Earth and planetary materials under laser-induced ultrahigh-pressure conditions

    Science.gov (United States)

    Tange, Y.; Ozaki, N.; Matsuoka, T.; Ogawa, T.; Albertazzi, B.; Habara, H.; Takahashi, K.; Matsuyama, S.; Yamauchi, K.; Tanaka, K.; Kodama, R.; Sato, T.; Sekine, T.; Seto, Y.; Okuchi, T.; Yabuuchi, T.; Inubushi, Y.; Yabashi, M.

    2015-12-01

    High-pressure and high-temperature in situ experiments have revealed behaviors of the earth and planetary constituents under extreme conditions, and contribute to progress our understandings about physical and chemical structure of planetary interiors. These in situ techniques have developed with the third-generation synchrotron radiation facilities such as APS, ESRF, and SPring-8 mainly using large volume presses and diamond anvil cells. In addition to the synchrotron light source, recently X-ray free electron laser (XFEL) facilities have been developed as LCLS and SACLA. The brilliant and extremely short-pulsed XFELs make it possible to carry out femto-second time-resolve measurements, and to observe materials under dynamic/shock compression clearly. Techniques using high-power laser and XFEL are expected to be a next-generation experimental platform, and a pump-probe measurement system using high-power lasers and XFEL was installed at BL3EH5 in SPring-8/SACLA interoperable experimental facility. The system is composed of 45 TW X-ray focusing system (KB mirrors), vacuumed sample chamber, and the MPCCD detector developed for the 10-fs ultra-short pulsed XFEL light source. The high-power laser enables us to generate up to 100 GPa for metal, simple oxide, and natural/synthesized mineral samples. Samples are mounted on sample holders and aligned at the center of the vacuum chamber using a 4-axis Goniometer head. In this presentation, we will overview the experimental setups and typical results of current pump-probe system using XFEL in SACLA.

  15. 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

  16. 变频均压防灭火控制系统的设计%System of Air Pressure Balance for Fire Control Based on Frequency Converter

    Institute of Scientific and Technical Information of China (English)

    蒋德智

    2013-01-01

      本文介绍了基于变频调速技术的矿井局扇风机控制系统的设计,该系统根据均压通风原理,通过传感器测量巷道进出风速、进风风门内外压差、一氧化碳浓等物理量,进行PID运算,调节变频器输出频率从而调节风机转速,实现风压和风量的动态平衡控制,在满足工作面正常通风的前提下,最大程度地减小采空区的漏风量,从而达到防灭火的目的。同时系统具有一氧化碳报警功能,当工作面发生起火现象时能够及时报警并采取相应的通风策略,减小或避免煤矿井下发生火险的可能性。%In this paper we introduced a design of pressure balance for air control system based on variable-frequency driver.This system is designed according to pressure balance for air theory,adjust the output frequency of VFD to regulate the motor speed,so we can realize the dynamic balance control of the air pressure and air quantity.The PID operation is based on the value of the wind speed sensor,air pressure sensor,CO concentration sensor.Under the premise of normal wind providing,we can reduce the catching fire possibility of mined-out area.Simultaneously,the system possesses the function of CO alarm,when the mined-out area is catching fire,system can generate a warning sign and take proper ventilation measure.

  17. 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).

  18. Predicted pressure-induced spin and electronic transition in double perovskite R2CoMnO6 (R = rare-earth ion)

    International Nuclear Information System (INIS)

    Specific first-principles calculations are performed to predict structural, magnetic and electronic properties of seven double perovskite R2CoMnO6 materials, with R being a rare-earth ion, under hydrostatic pressure. All these compounds are found to undergo a first-order transition from a high spin (HS) to low spin (LS) state at a critical pressure (whose value is dependent on the R ion). Such transition not only results in a significant volume collapse but also yields a dramatic change in electronic structure. More precisely, the HS-to-LS transition is accompanied by a transition from an insulator to a half-metallic state in the R2CoMnO6 compounds having the largest rare-earth ionic radius (i.e., Nd, Sm, Gd and Tb) while it induces a change from an insulator to a semiconductor having a narrow band gap for the smallest rare-earth ions (i.e., R = Dy, Ho and Er). Experiments are called for to confirm these predictions. (paper)

  19. Temperature of Earth's Deep Interior Constrained from Melting of Fe and Fe0.9Ni0.1 at High Pressures

    Science.gov (United States)

    Zhang, D.; Jackson, J. M.; Zhao, J.; Sturhahn, W.; Alp, E. E.; Hu, M. Y.; Toellner, T.; Murphy, C. A.; Prakapenka, V.

    2015-12-01

    The melting points of fcc- and hcp-structured Fe0.9Ni0.1 and Fe have been measured up to Mbar pressure. We use laser heated diamond anvil cells, time-resolved synchrotron Mössbauer spectroscopy, x-ray diffraction and a recently developed fast temperature readout spectrometer to carry out these measurements. X-ray photons at 57Fe's resonant energy with 1 meV bandwidth are focused on the sample in a laser heated diamond anvil cell, and when melting occurs, the characteristic Mössbauer signal abruptly decreases. Thus, time-resolved Mössbauer spectroscopy provides an excellent diagnostic for the first melt formed in the sample chamber. The thermal contributions of pressure of Fe0.9Ni0.1 and Fe have been constrained by combining nuclear resonant inelastic scattering and high temperature X-ray diffraction measurements. We find that the melting curve of Fe is systematically higher than the melting curve of Fe0.9Ni0.1, while the 1-σ temperature uncertainties of both melting curves overlap. The pressure dependencies of the melting temperature of fcc-structured Fe and Fe0.9Ni0.1 are measured, and the best-fit melting curves are located in the region bounded by previous studies. Our results may help reach a consensus on the high pressure melting curves of Fe and Fe-Ni alloys. We calculate the fcc-hcp-liquid triple points of Fe0.9Ni0.1and Fe, complemented by experiments with Mössbauer spectroscopy. The upper bound of Earth's inner core-outer core boundary temperature is estimated from our results, and the upper bound of the temperature at Earth's core-mantle boundary is computed with an adiabatic model. We discuss the implications of these temperatures on the phase relations of deep Earth materials. References:Murphy, C.A., J.M. Jackson, W. Sturhahn, and B. Chen (2011): Melting and thermal pressure of hcp-Fe from the phonon density of states, Phys. Earth Planet. Int., 188, 114-120 Jackson, J.M., W. Sturhahn, M. Lerche, J. Zhao, T.S. Toellner, E.E. Alp, S.V. Sinogeikin, J

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

    Energy Technology Data Exchange (ETDEWEB)

    Morozova, Natalia V.; Shchennikov, Vladimir V. [M. N. Miheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences, 18 S. Kovalevskaya Str., Yekaterinburg 620137 (Russian Federation); Ovsyannikov, Sergey V., E-mail: sergey.ovsyannikov@uni-bayreuth.de, E-mail: sergey2503@gmail.com [Bayerisches Geoinstitut, Universität Bayreuth, Universitätsstrasse 30, Bayreuth D-95447 (Germany); Institute for Solid State Chemistry of Ural Branch of Russian Academy of Sciences, 91 Pervomayskaya Str., Yekaterinburg 620990 (Russian Federation)

    2015-12-14

    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.

  1. UNIFIED METHOD OF SEPARATE AND COMBINED CALCULATION OF WATER AND EARTH PRESSURES%水土压力分算与合算的统一算法

    Institute of Scientific and Technical Information of China (English)

    王洪新

    2011-01-01

    Applying combined calculation of water and earth pressures for clay leads to a result which is more close to the field measurement value, however, obviously violates the principle of effective stress. Based on characteristics of the pore water in soil, it is assumed that the bound water absorbed by the clay particles in the soil offsets part of soil pore, and finally physical parameters such as void ratio, boundary water content, particle analysis, etc. are introduced to calculation of water and earth pressures on retaining structures to propose a coefficient ξ which can be calculated through physical parameters of soil and to provide the method of measuring the value of ξ through permeability tests. With the coefficient ξ, the effective stress intensity index and total stress intensity index are integrated in one strength formula. A new calculation method to unify the separate calculation and combined calculation of water and earth pressures is proposed to carry out the transition between results of the two conventional calculation methods and provide a new idea for solving the jump problem between the two results. According to the theory analysis of this paper, the measured permeability coefficient-void ratio curve will have a translational move in a forward direction along e-axis. The more clay particles that soil contains will have the larger translation, which has been verified by experimental data of related literatures. Separate calculation of water and earth pressures is too conventional for sand soil containing clay particles while combined calculation of water and earth pressures for clay with high void ratio can't guarantee the safety. Water and earth pressures on retaining structure are related not only to the soil categories, but also the void ratio.%以土中孔隙水特征为基础,假定土体中的黏性土颗粒吸附的结合水会抵消一部分土中孔隙,最终把土的孔隙比、界限含水量、颗粒分析等物理参数引入土水

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

    Science.gov (United States)

    Richard, G. A.

    2003-12-01

    Major research facilities and organizations provide an effective venue for developing partnerships with educational organizations in order to offer a wide variety of educational programs, because they constitute a base where the culture of scientific investigation can flourish. The Consortium for Materials Properties Research in Earth Sciences (COMPRES) conducts education and outreach programs through the Earth Science Educational Resource Center (ESERC), in partnership with other groups that offer research and education programs. ESERC initiated its development of education programs in 1994 under the administration of the Center for High Pressure Research (CHiPR), which was funded as a National Science Foundation Science and Technology Center from 1991 to 2002. Programs developed during ESERC's association with CHiPR and COMPRES have targeted a wide range of audiences, including pre-K, K-12 students and teachers, undergraduates, and graduate students. Since 1995, ESERC has offered inquiry-based programs to Project WISE (Women in Science and Engineering) students at a high school and undergraduate level. Activities have included projects that investigated earthquakes, high pressure mineral physics, and local geology. Through a practicum known as Project Java, undergraduate computer science students have developed interactive instructional tools for several of these activities. For K-12 teachers, a course on Long Island geology is offered each fall, which includes an examination of the role that processes in the Earth's interior have played in the geologic history of the region. ESERC has worked with Stony Brook's Department of Geosciences faculty to offer courses on natural hazards, computer modeling, and field geology to undergraduate students, and on computer programming for graduate students. Each summer, a four-week residential college-level environmental geology course is offered to rising tenth graders from the Brentwood, New York schools in partnership with

  3. Analysis on Influencing Factors of the Actual Earth Pressure of Foundation Pit%基坑真实土压力的影响因素分析

    Institute of Scientific and Technical Information of China (English)

    宋明健; 杨庆; 钟义敏

    2011-01-01

    Accurate earth pressure is the key factor to ensure the safety and stability of foundation pit.Combined with the recent research progress in foundation pit engineering,various influencing factors of the actual earth pressure are analyzed and described,and the awareness of these factors in the current design construction is summarized in this paper.Based on this,this paper also puts forward some suggestions on acquiring the actual earth pressure,such as to master accurate environmental and geotechnical information,strengthen studies on calculation method and space-time coupling theory,establish regional geotechnical information management system,adopt dynamic design based on back analysis,and use dynamic supporting technology closed integrated with monitoring information.%土压力的准确分析是确保基坑安全稳定的关键。结合基坑工程的最新研究进展,对真实土压力的诸多影响因素进行了分析和论述,并简要归纳了目前设计施工中对这些影响因素的认识现状。在此基础上,提出了把握真实土压力的一些建议:准确掌握环境岩土信息;加强计算方法、时空耦合效应等理论的研究;建立区域岩土信息管理系统;采用以反分析为基础的动态设计;使用与监测信息密切结合的动态支护技术等。

  4. Experimental investigation of anaerobic nitrogen fixation rates with varying pressure, temperature and metal concentration with application to the atmospheric evolution of early Earth and Mars.

    Science.gov (United States)

    Gupta, Prateek

    2012-07-01

    The atmosphere of the early Earth is thought to have been significantly different than the modern composition of 21% O2 and 78% N2, yet the planet has been clearly established as hosting microbial life as far back as 3.8 billion years ago. As such, constraining the atmospheric composition of the early Earth is fundamental to establishing a database of habitable atmospheric compositions. A similar argument can be made for the planet Mars, where nitrates have been hypothesized to exist in the subsurface. During the early period on Mars when liquid water was likely more abundant, life may have developed to take advantage of available nitrates and a biologically-driven Martian nitrogen cycle could have evolved. Early Earth atmospheric composition has been investigated numerically, but only recently has the common assumption of a pN2 different than modern been investigated. Nonetheless, these latest attempts fail to take into account a key atmospheric parameter: life. On modern Earth, nitrogen is cycled vigorously by biology. The nitrogen cycle likely operated on the early Earth, but probably differed in the metabolic processes responsible, dominantly due to the lack of abundant oxygen which stabilizes oxidized forms of N that drive de-nitrification today. Recent advances in evolutionary genomics suggest that microbial pathways that are relatively uncommon today (i.e. vanadium and iron-based nitrogen fixation) probably played important roles in the early N cycle. We quantitatively investigate in the laboratory the effects of variable pressure, temperature and metal concentration on the rates of anoxic nitrogen fixation, as possible inputs for future models investigating atmospheric evolution, and better understand the evolution of the nitrogen cycle on Earth. A common anaerobic methanogenic archaeal species with i) a fully sequenced genome, ii) all three nitrogenases (molybdenum, vanadium and iron-based) and iii) the ability to be genetically manipulated will be used as

  5. 挡土墙被动土压力的滑移线解%Slip-line solution to passive earth pressure on retaining walls

    Institute of Scientific and Technical Information of China (English)

    彭明祥

    2011-01-01

    Based on the limit equilibrium theory, the backfill is treated as a perfectly elastic-plastic material which follows the Mohr-Coulomb yield criterion, and is assumed to be an isotropic, homogeneous and incompressible (or non-expansive) perfectly continuous medium.The stress singularity and its stress boundary condition are introduced, and' a statically determinate and solvable mathematical model for the limit equilibrium boundary value problem is established without considering the stress-strain relationship.Then the slip-line field and stress field in plastic zone of the backfill are solved by use of the slip-line method, furthermore, the passive earth pressure on retaining walls and the reaction on slip surfaces are derived.Geometric and mechanical similarity principle is presented by means of dimensionless analysis.The results show that the slip-line solution to the passive earth pressure is generally less than or equal to the Coulomb's solution, and the classical Rankine's earth pressure or the classical Coulomb's earth pressure satisfying non-singularity condition is in accordance with the slip-line solution, and the Hencky's first theorem and second theorem are not generally applicable.%基于极限平衡理论,视墙后填土为服从Mohr-Coulomb屈服准则的理想弹塑性材料,并且假定它是各向同性的、均匀的以及不可压缩(膨胀)的理想连续介质.引进了应力奇点及其应力边界条件,建立了静定可解的极限平衡边值问题数学模型,而不必考虑土的应力-应变关系,采用滑移线法求解了墙后塑性区的滑移线场和应力场,进而求解了挡土墙被动土压力和滑裂面土反力.通过无量纲分析,提出了几何力学相似原理.数值分析表明,被动土压力的滑移线解一般总是小于或等于库仑解,经典朗肯土压力或满足非奇异条件的经典库仑土压力与滑移线解一致,Hencky第一定理和第二定理不具有普遍适用性.

  6. 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.

  7. Unified solution of Coulomb's active earth pressure for unsaturated soils%非饱和土库仑主动土压力统一解

    Institute of Scientific and Technical Information of China (English)

    赵均海; 梁文彪; 张常光; 李艳

    2013-01-01

    基于非饱和土双应力状态变量抗剪强度统一解,合理考虑中间主应力效应,建立了非饱和土库仑主动土压力统一解,并对其进行可比性分析,将其计算结果与非饱和土朗肯主动土压力统一解进行对比,得出各因素的影响特性.研究结果表明,中间主应力和基质吸力对库仑主动土压力的影响显著,随统一强度理论参数和基质吸力的增加,库仑主动土压力不断减小直至为0,证明了考虑中间主应力可以充分发挥材料的自承载能力和强度潜能,具有可观的经济效益;库仑主动土压力随墙背倾角与填土倾角的增大而增大,随有效内摩擦角和基质吸力角的增大而减小,外摩擦角的影响不显著.非饱和土库仑主动土压力统一解具有更广泛的适用性,朗肯主动土压力统一解为其特例,其结果对边坡、基坑等工程的土压力确定和支挡结构设计有很好的借鉴作用.%Based on the unified solution of shear strength in terms of two stress state variables for unsaturated soils, the unified solution of Coulomb's active earth pressure for unsaturated soils is proposed which considers the effect of the intermediate principal stress rationally. Moreover, the comparability of this unified solution is analyzed. Influential characteristic of each factor is discussed by comparing with the unified solution of Rankine active earth pressure. The result shows that: the effects of intermediate principal stress and matric suction are significant; the Coulomb's active earth pressure decreases until zero with the increase of the unified strength theory parameter and matric suction, which indicates that the consideration of the intermediate principal stress effect can make materials give full play to their self-bearing capacities and strength potential, bringing obvious economic benefits to the project; the Coulomb's active earth pressure increases with the increase of the grading angle of retaining wall

  8. 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.

  9. Anti-overturning stability analysis of cement-soil gravity retaining wall under different earth pressure modes%考虑不同土压力模式的水泥土重力式围护墙抗倾覆稳定性分析

    Institute of Scientific and Technical Information of China (English)

    毛明强; 熊巨华

    2014-01-01

    墙前开挖区土压力和墙后土压力模式的确定是水泥土重力式挡土墙抗倾覆稳定性验算的关键,不同土压力模式下抗倾覆系数曲线形态有一定的差异。根据墙体竖向力的平衡确定抗倾覆验算点位置,根据墙体的变形特征,同时考虑由于基坑开挖引起的上覆有效土压力变化引入修正系数α修正墙前后土压力,推导了修正土压力模式下墙体的抗倾覆稳定计算公式,对比分析三种不同土压力模式下Kq曲线的形态特征及其影响因素,结果表明墙前后土压力修正模式更能反映实际状态下墙的倾覆失稳形态,其抗倾覆稳定系数也更加合理。%The mode of earth pressures acting on the front wall and behind the wall plays a key role in checking the anti-overturning stability of cement-soil gravity retaining wall after excavation. The curve of anti-overturning safety factor somewhat varies under different earth pressure modes. The turning point can be determined according to the balance of vertical force. In order to consider the characteristics of wall deformation and the change of effective vertical earth pressure, a coefficient is introduced to modify the earth pressure on the wall, meanwhile a formula for calculating the safety factor is proposed under the new mode. Through analysis of the morphological characteristics of the curve and the influencing factor under three different earth pressure modes, the calculated results show that the anti-overturning safety factor is more reasonable, and the modified method can better reveal the real state of wall overturning.

  10. Atomistic and Ab initio modeling of CaAl2O4 high-pressure polymorphs under Earth's mantle conditions

    Science.gov (United States)

    Eremin, N. N.; Grechanovsky, A. E.; Marchenko, E. I.

    2016-05-01

    Semi-empirical and ab initio theoretical investigation of crystal structure geometry, interatomic distances, phase densities and elastic properties for some CaAl2O4 phases under pressures up to 200 GPa was performed. Two independent simulation methods predicted the appearance of a still unknown super-dense CaAl2O4 modification. In this structure, the Al coordination polyhedron might be described as distorted one with seven vertices. Ca atoms were situated inside polyhedra with ten vertices and Ca-O distances from 1.96 to 2.49 Å. It became the densest modification under pressures of 170 GPa (density functional theory prediction) or 150 GPa (semi-empirical prediction). Both approaches indicated that this super-dense CaAl2O4 modification with a "stuffed α-PbO2" type structure could be a probable candidate for mutual accumulation of Ca and Al in the lower mantle. The existence of this phase can be verified experimentally using high pressure techniques.

  11. 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.

  12. 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 ...

  13. 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)

  14. 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

  15. 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.

  16. 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.

  17. Rare—Earth Element Geochemistry of Elogites from the Ultra—High Pressure Metamorphic Belt in Central China

    Institute of Scientific and Technical Information of China (English)

    黄智龙; 刘丛强; 等

    2000-01-01

    Based on their REE contents and REE patterns,eclogites from the ultra-high pressure metamorphic belt in central China may be roughly divided into xis types including LREE-rich.LREE-rich+positive Eu anomaly,LREE-rich+negative Eu anomaly,REE pattern-smooth,MREE-rich and HREE-rich.The LREE_rich,LREE-rich+positive Eu anomaly and LREE-rich+negative Eu anomaly types of eclogites are dominant .REE types of eclogites in different areas can be compared and the REE feactures of the same REE type of eclogites in different areas are similar.The results of reconstruction of the primary rocks show that the primary rocks of eclogites possibly are dominated by continental tholeiites which are the product of partial melting of relatively fertile mantle and the rocks of tholeiite crystallization-differentiation.There is perfect evolution relationship among the primary rocks of the LREE-rich, LREE-rich+positive Eu anomaly and LREE-rich+negative Eu anomaly types of eclogites and among those of the REE pattern smooth and MREE-rich types of eclogites,the former three types were deried from continental settings and the latter two from nearly oceanic settings.Meanwhile,it is concluded that the mantle sources of primary rocks of the eclogites are inhomogeneous and the primary rocks of eclogites in this area appear to have undergone varying degree of crustal contamination.

  18. 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.

  19. 土压平衡盾构伸缩螺旋机的设计%Design of earth pressure balance shield telescopic screw conveyor

    Institute of Scientific and Technical Information of China (English)

    洪秋华

    2011-01-01

    阐述了土压平衡盾构螺旋机的一种新型设计思路,提出了带导向柱油缸及双闸门系统的伸缩式螺旋机,提供了满足其推进要求所必须的参数,为盾构伸缩式螺旋机的实际应用提供了理论依据.

  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. X-ray diffraction and Mössbauer spectroscopy study of fcc iron hydride FeH at high pressures and implications for the composition of the Earth's core

    Science.gov (United States)

    Narygina, Olga; Dubrovinsky, Leonid S.; McCammon, Catherine A.; Kurnosov, Alexander; Kantor, Innokenty Yu.; Prakapenka, Vitali B.; Dubrovinskaia, Natalia A.

    2011-07-01

    The phase fcc FeH x (x ~ 1) was synthesized at pressures over 30 GPa and temperatures over 1600(50) K. At room temperature this iron hydride is stable at pressures from 19(1) GPa up to at least 68(2) GPa (the highest pressure achieved in this study). A fit of the PV data collected for fcc FeH x at room temperature gives the following parameters for the equation of state: V 0 = 53.8(3) Å 3, K 0 = 99(5) GPa, K' = 11.7(5). Using this data the amount of H required to match the density of the Earth's core was estimated to be 0.5-1 wt.% hydrogen in the outer core and 0.08-0.16 wt.% hydrogen in the inner core. Our results also suggest that hydrogen and carbon do not occur together in the Earth's core.

  2. 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...

  3. Temperature of Earth's core constrained from melting of Fe and Fe0.9Ni0.1 at high pressures

    Science.gov (United States)

    Zhang, Dongzhou; Jackson, Jennifer M.; Zhao, Jiyong; Sturhahn, Wolfgang; Alp, E. Ercan; Hu, Michael Y.; Toellner, Thomas S.; Murphy, Caitlin A.; Prakapenka, Vitali B.

    2016-08-01

    The melting points of fcc- and hcp-structured Fe0.9Ni0.1 and Fe are measured up to 125 GPa using laser heated diamond anvil cells, synchrotron Mössbauer spectroscopy, and a recently developed fast temperature readout spectrometer. The onset of melting is detected by a characteristic drop in the time-integrated synchrotron Mössbauer signal which is sensitive to atomic motion. The thermal pressure experienced by the samples is constrained by X-ray diffraction measurements under high pressures and temperatures. The obtained best-fit melting curves of fcc-structured Fe and Fe0.9Ni0.1 fall within the wide region bounded by previous studies. We are able to derive the γ-ɛ-l triple point of Fe and the quasi triple point of Fe0.9Ni0.1 to be 110 ± 5GPa, 3345 ± 120K and 116 ± 5GPa, 3260 ± 120K, respectively. The measured melting temperatures of Fe at similar pressure are slightly higher than those of Fe0.9Ni0.1 while their one sigma uncertainties overlap. Using previously measured phonon density of states of hcp-Fe, we calculate melting curves of hcp-structured Fe and Fe0.9Ni0.1 using our (quasi) triple points as anchors. The extrapolated Fe0.9Ni0.1 melting curve provides an estimate for the upper bound of Earth's inner core-outer core boundary temperature of 5500 ± 200K. The temperature within the liquid outer core is then approximated with an adiabatic model, which constrains the upper bound of the temperature at the core side of the core-mantle boundary to be 4000 ± 200K. We discuss a potential melting point depression caused by light elements and the implications of the presented core-mantle boundary temperature bounds on phase relations in the lowermost part of the mantle.

  4. 增高鞋垫对足底压力分布及后跟平衡的影响%The Effect of Heighten Insole on Pressure Distribution and Heel Balance

    Institute of Scientific and Technical Information of China (English)

    张先熠; 李悦; 李罗浩; 李波

    2013-01-01

    通过测量穿增高鞋垫前后足底压力参数,探究增高鞋垫对足底压力分布与后跟部位平衡的影响.用Footscan压力板与Novel鞋垫系统测量15名大学生穿板鞋及穿垫有增高鞋垫的板鞋行走时的压力参数,比较二者在足底7个分区的接触时间、峰值压强与冲量,以及后跟内外侧压力差值.结果显示:穿增高鞋垫后,足底各区域接触时间均延长,大部分区域峰值压强降低,部分冲量由前尖转移向后跟,后跟部位内外翻加剧,从而平衡稳定性能降低.%This study aimed to investigate the effect of heighten insole on plantar pressure distribution and heel balance by analyzing plantar pressure measurements with and without heighten insole. Footscan Force Plate and Novel Pedar - X system were used to measure plantar pressure for 15 undergraduates wearing board shoe with and without heighten insole. The measurements of two conditions were compared. Analysis parameters of seven regions included contact time, peak pressure, impulsing on and the force difference between medial heel and lateral heel. The results showed that when wearing heighten insole; the contact time was increased on all regions and peak pressure was decreased on most regions; some pressure was transferred from the toes to heel region; the balance and stability were decreased with heel supination increased.

  5. On the radial force balance in the quiet time magnetotail current sheet

    Science.gov (United States)

    Artemyev, A. V.; Angelopoulos, V.; Runov, A.

    2016-05-01

    Using Time History of Events and Macroscale Interactions spacecraft observations of the quite magnetotail current sheet within the r∈[9,35]RE region (r is the radial distance from Earth and RE is Earth's radius), we investigate the thermal plasma pressure distribution along the magnetotail. Taking advantage of flapping motions of an ensemble of current sheets at various distances, we estimate the current density magnitude jy (in GSM coordinates). Comparing the tension force jyBz (Bz is the magnetic field component) with the radial gradient of the plasma pressure demonstrates that this gradient is only a small fraction, ˜10-15%, of the Ampere force exerted on the cross-tail current, in the r > 15RE region. We also estimate the contribution of the electron temperature anisotropy to the pressure balance: in the r > 15RE region the corresponding force can balance only 10-15% of the observed tension force jyBz. Thus, we conclude that about 70% of the tension force is not balanced by the combination of isotropic radial pressure gradient or the electron anisotropy. We discuss mechanisms that could be responsible for balancing the magnetotail current sheet.

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

    Science.gov (United States)

    Laurijssen, Ilse; Glorieux, Ignace

    2013-01-01

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

  7. Balanced sampling

    NARCIS (Netherlands)

    Brus, D.J.

    2015-01-01

    In balanced sampling a linear relation between the soil property of interest and one or more covariates with known means is exploited in selecting the sampling locations. Recent developments make this sampling design attractive for statistical soil surveys. This paper introduces balanced sampling

  8. 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.)

  9. A fluid model for the edge pressure pedestal height and width in tokamaks based on the transport constraint of particle, energy, and momentum balance

    Science.gov (United States)

    Stacey, W. M.

    2016-06-01

    A fluid model for the tokamak edge pressure profile required by the conservation of particles, momentum and energy in the presence of specified heating and fueling sources and electromagnetic and geometric parameters has been developed. Kinetics effects of ion orbit loss are incorporated into the model. The use of this model as a "transport" constraint together with a "Peeling-Ballooning (P-B)" instability constraint to achieve a prediction of edge pressure pedestal heights and widths in future tokamaks is discussed.

  10. 滑裂面形状对挡土墙主动土压力的影响%Effect of slip surface shape on active earth pressure upon retaining wall

    Institute of Scientific and Technical Information of China (English)

    徐杨; 阎长虹; 姜玉平; 许宝田

    2015-01-01

    滑裂面的准确选取对挡土墙稳定性分析有重要影响。基于塑性极限分析理论,分别推导了直线和对数螺旋线滑移模式下挡土墙主动土压力的计算公式,通过算例对比分析研究了平面滑裂面和对数螺旋滑裂面主动土压力的特点。研究结果表明:直线滑裂面为对数螺旋滑裂面的一种特例,随着滑裂面曲率增大,主动土压力合力作用点逐渐上移,主动土压力合力略有增加,但对墙趾的弯矩显著增加,不利于挡土墙稳定性;挡土墙各参数对直线滑裂面主动土压力合力作用点有不同影响,随着填土内摩擦角、挡墙倾角、填土倾角的增大而上移,随着墙土间摩擦角、黏聚力与容重挡土墙高度的乘积之比的增大而下移,合力作用点位置大致在0.2~0.4倍墙高处,说明主动土压力的非线性分布。研究结果对准确选取滑裂面形状计算挡土墙主动土压力有实际工程应用价值。%Based on the plastic limit analysis theory, the calculation formulas of active earth pressure for retaining wall were derived at the linear and logarithmic spiral slip pattern respectively. And the features of active earth pressure between the plane slip surface and logarithmic spiral slip surface were also compared through the calcula-tion examples. The linear slip surface is considered as a special case of the logarithmic spiral slip surface the point of resultant force of active earth pressure for linear slip surface was determined by the combination of the two cal-culation formulas. With the increase of slip surface curvature, the point of resultant force of active earth pressure gradually moves up, the value of active earth pressure slightly increases but there is significant increase in the moment of the wall toe. The parameters of the retaining wall were analyzed to study its influence on the point of resultant force of active earth pressure for linear slip surface. The

  11. Experimental study of soil arching and transfer behavior of earth pressure about sheet-pile walls%桩板墙土拱效应及土压力传递特性试验研究

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    In order to further study the soil arching behind the sheet-pile wall and analyze the earth pressure load regulation and transmission characteristic, the field large-sized test and indoor model test are carried out by monitoring research. In addition, the test results can further reveal the regularities about soil arching and load distribution. Based on the comprehension of the action mechanism about the soil arching structure, the ratio between the earth pressure on the back side of pile and pressure on the breast board is regarded as a standard which is used to assess the arching. A test model box is designed and constructed in order to load behind sheet-pile wall at a rock slope. The earth pressure cells are fixed on the dorsal surfaces of sheet and piles to test the earth pressure during future 21 days. The test results show that the earth pressure ratio increases firstly and then tends to be stable as the development of time; therefore, the time effect is relatively obvious. In addition, multiple test conditions are also designed and done to make further analysis about the relationship between the soil arching and transfer behavior of earth pressure behind sheet-pile wall. The comparative researches are done about different baffle rigidities, pile spacings, filler properties and arrangement effects of sheets, which explains the transfer behavior of load behind sheet-pile wall in the passive soil pressure state.%  为更深入地研究桩板墙背侧的土拱效应,分析其土压力荷载的作用规律及传递特性,进一步揭示桩板墙土拱效应与荷载分配之间的联系,采用现场大型试验及室内模型试验开展相关的监测研究工作。基于对土拱结构承载机制的认识,将作用于桩背侧与桩间挡板中部土压力的比值作为衡量土拱效应作用效果的直观标准。在某一自然边坡上,设计施工桩板墙堆载试验的模型槽,在挡土板与抗滑桩背侧分别安装

  12. Informational Balance

    OpenAIRE

    Müller, Henrik Høeg

    2011-01-01

    The title of my talk is “Informational balance. Understanding Romance and Germanic Compounding in a lexico-typological perspective”. What I basically mean by informational balance is that semantic content is distributed systematically differently between nouns and verbs in the Romance and Germanic languages, and that this distribution is complementary. I shall explain that in detail in a minute, but first I shall introduce you to the problem, which I believe can be explained on the basis of t...

  13. 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 p<0.01). ICCs in the VI group ranged from 0.73 to 0.95, indicating high to very high correlations, and the normal group showed moderate to very high ICCs (0.62-0.94). The SEM was comparable between groups regardless of between-subject variability. The reliability of the WBB makes it practical to screen for balance impairment among VI persons. PMID:25555361

  14. 姿势控制训练对偏瘫患者足底压力及平衡功能的影响%Influence of postural control training on plantar pressure and balance function of hemiparalysis patient

    Institute of Scientific and Technical Information of China (English)

    刘蓓蓓; 丁勤能; 王岩

    2014-01-01

    Objective To explore the influence of postural control training on plantar pressure and balance function of hemip -aralysis patient .Methods Twenty-four cases of hemiparalysis patients were selected and divided into two groups of traditional group ( TG) and balance group ( BG) and had been taken postural control trainings .Novel Zebris pressure test platform was used to examine the pressure peak value (PPV),average pressure (AP),ellipse track length (ETL) of pressure center deviation including ellipse area ( EA) after postural control trainings .Results After two different training methods:①Compared with TG ,PPVs of front half foot and back half foot of unaffected side were both decreased significantly (P0.05).②Compared with TG,AP of front half foot in unaffected side decreased significantly and that in back half foot in-creased significantly (P0.05).③Compared BG with TG,EA,ETL and ratio between ETL and EA decreased significantly (P<0.05).Conclusion ①After two pos-tural control trainings ,there is no significant alteration on contact mode between feet and ground ,and feet pressure distribution condi-tion.Body’s methods to maintain balance have not been changed .②Both feet pressure balance abilities of hemiparalysis patients have been improved after two postural control trainings that indicate they are effective to increase hemiparalysis patients ’ balance function .③Steady trainings in BG promote the improvement of balance function and coordination ability .④BG had obvious advantages than TG in regaining balance adjustment function .%目的:探讨偏瘫患者在进行姿势控制训练后足底压力的变化及对平衡功能的影响。方法将24例偏瘫患者随机分为传统组和平衡组并进行姿势控制训练。使用Novel Zebris平板式足底压力系统测试患者训练后足底的压力峰值、平均压力、压力中心偏移的椭圆轨迹长度,以及椭圆轨迹包络面积。结果经过姿势训练后,①平衡组

  15. 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

  16. 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…

  17. Balance (or Vestibular) Rehabilitation

    Science.gov (United States)

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

  18. Pressure fluctuation performance of low specific-speed centrifugal pump with radial reflux balance hole/%采用径向回流平衡孔的低比速离心泵压力脉动特性

    Institute of Scientific and Technical Information of China (English)

    曹卫东; 张晓娣; 施卫东

    2011-01-01

    采用Relizablek~ε模型对具有径向回流平衡孔以及传统轴向回流平衡孔和无平衡孔结构的低比速离心泵进行全流场非定常数值模拟,并进行时域分析和频域分析.研究结果表明:平衡孔采用径向回流方式、传统轴向回流方式以及无平衡孔结构这3种方案时,离心泵的叶轮进口、蜗壳出口以及蜗壳隔舌处的流体均随时间呈周期性波动,脉动频率以叶片通过频率为主;具有径向回流平衡孔的低比速离心泵与其他2种结构形式的低比速离心泵相比,能够有效地改善蜗壳隔舌处的压力脉动情况.%By means of the k-ε model, numerical simulation of unsteady full flow fields of low specific-speed centrifugal pump with three different structures, that is, radial reflux balance hole, traditional axial reflux balance hole and no balance hole, was carried out. The time domain and frequency domain were analyzed. The results show that for the above three kinds of structures, the fluid at the inlet of the impeller, outlet and tongue of the volute exhibits cyclic fluctuation with the time, and the fluctuating frequency is mainly the passing frequency of the blade. Compared with that with the other two structures, the low specific-speed centrifugal pump with radial reflux balance hole will effectively improve the pressure fluctuation at the tongue of the volute.

  19. High-Pressure Synthesis of Melilite-type Rare-Earth Nitridophosphates RE2P3N7 and a Ba2Cu[Si2O7]-type Polymorph.

    Science.gov (United States)

    Kloß, Simon D; Weidmann, Niels; Niklaus, Robin; Schnick, Wolfgang

    2016-09-19

    High-pressure metathesis was proposed to be a gateway to the elusive class of rare-earth nitridophosphates. With this method the first ternary compounds of this class with sum formula RE2P3N7 were prepared, a melilite-type with RE = Pr, Nd, Sm, Eu, Ho, Yb (Ho2P3N7: P4̅21m, a = 7.3589(2), c = 4.9986(2) Å, Z = 2) and a Ba2Cu[Si2O7] structure type with RE = La, Ce, Pr (Pr2P3N7: monoclinic, C2/c, a = 7.8006(3), b = 10.2221(3), c = 7.7798(3) Å, β = 111.299(1)°, Z = 4). The phase relation between the two structure types was prior unknown and is here evidenced by experimental data as well as density functional theory calculations performed for the Pr2P3N7 compounds. Adequate classification of both structures types with regard to Liebau nomenclature, vertex symbol, and point symbol is made. Additionally, the tiling patterns of the monolayered structures are deducted. We demonstrate that high-pressure metathesis offers a systematic access to rare-earth nitridophosphates with an atomic ratio of P/N between 1/2 and 1/4. PMID:27579899

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

    Energy Technology Data Exchange (ETDEWEB)

    Bosch, R.W.; Van Nieuwenhove, R

    1998-10-01

    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.

  1. 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

  2. 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

  3. 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...

  4. Anomalous density and elastic properties of basalt at high pressure: Reevaluating of the effect of melt fraction on seismic velocity in the Earth's crust and upper mantle

    Science.gov (United States)

    Clark, Alisha N.; Lesher, Charles E.; Jacobsen, Steven D.; Wang, Yanbin

    2016-06-01

    Independent measurements of the volumetric and elastic properties of Columbia River basalt glass were made up to 5.5 GPa by high-pressure X-ray microtomography and GHz-ultrasonic interferometry, respectively. The Columbia River basalt displays P and S wave velocity minima at 4.5 and 5 GPa, respectively, violating Birch's law. These data constrain the pressure dependence of the density and elastic moduli at high pressure, which cannot be modeled through usual equations of state nor determined by stepwise integrating the bulk sound velocity as is common practice. We propose a systematic variation in compression behavior of silicate glasses that is dependent on the degree of polymerization and arises from the flexibility of the aluminosilicate network. This behavior likely persists into the liquid state for basaltic melts resulting in weak pressure dependence for P wave velocities perhaps to depths of the transition zone. Modeling the effect of partial melt on P wave velocity reductions suggests that melt fraction determined by seismic velocity variations may be significantly overestimated in the crust and upper mantle.

  5. 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......, with two minor categories: Assessing depression and antidepressants and Evaluating the impact of significant others. The participants tried to make the safest decision, taking all aspects of their life into consideration. They described successful decision-making in the context of managing social norms...

  6. 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...

  7. 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...

  8. 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.

  9. Phase states of hydrous-hydrocarbon fluids at elevated and high temperatures and pressures: Study of the forms and maximal depths of oil occurrence in the Earth's interior

    Science.gov (United States)

    Balitsky, V. S.; Penteley, S. V.; Pironon, J.; Barres, O.; Balitskaya, L. V.; Setkova, T. V.

    2016-02-01

    Based on synthetic fluid inclusions in quartz grown at 240-490°C and 7-150 MPa in aqueous-oil solutions, the behavior, composition, and phase states of liquid, gaseous, and solid hydrocarbons (HC) were studied. Investigations were performed using common and fluorescent microscopy, microthermometry, local common and high-temperature IR Fourier spectroscopy, Raman spectroscopy, chromatography, and X-ray and microprobe analysis. The data obtained allowed us to understand the influence of thermobaric conditions and volume proportions of the oil, aqueous, and gaseous phases on the composition, phase state, and behavior of hydrous-hydrocarbon fluids and estimate the forms and probable maximal depths of the origin of oil in the Earth's interior.

  10. Solutions based on load balancing technology to the access pressure of network tasks%基于负载均衡技术的网络作业系统访问压力解决方案

    Institute of Scientific and Technical Information of China (English)

    于梅英; 张海波; 王春彦

    2011-01-01

    为解决网上作业系统访问压力与数据阻塞问题,提出了一种应用缓存技术、负载均衡技术的解决方案,并对网上作业系统的信息载入慢、服务器压力大、成绩试算次数过多3个关键问题设计了相应的解决算法.经兰州大学网络教育学院网上作业系统运行验证,表明实施解决方案后,能够有效地降低因访问过于集中而引起的网络阻塞和死锁问题,提高作业系统的稳定性和有效性.%In order to solve the problem of the high access pressure of network task system and data blocking, this article proposes solutions based on cache technology and load balancing technology,and a plan for solving three key problems: low speed of information load of network task system, high pressure of server and too many times of pilot calculation for scores. We also tested the network task system on the website of Lanzhou University Distance Education College. The result shows that applying it can effectively solve the problem of network being blocked or locked caused by excessive access so as to enhance the stability and effectiveness of the network task system.

  11. NON-LIMIT STATE EARTH PRESSURE AGAINST RETAINING WALL CONSIDERING INFLUENCE OF DEFORMATION%考虑变位影响的刚性挡墙非极限土压力研究

    Institute of Scientific and Technical Information of China (English)

    陈奕柏; 柯才桐; 高洪波; 陈云

    2015-01-01

    The classic theory of earth pressure can only be used to calculate the limit earth pressure on the retaining wall under the mode of translation. With the Mohr circle expressed with the principal stress difference and on the basis of the radial stress-strain relation obtained from the stress path triaxial tests,the nonlinear relationships of the mobilized internal friction angle of the soil and the friction angle between the wall and the backfill soils vesus the displacement were established under non-limit state. The method of effective area ratio of wall displacement was put forward to quantify the relationship to rigid retaining wall under the deformation mode of rotation. Based on the method above and combined with the method of horizontal slices and the modified Coulumb′s formula,the formula of earth pressure distribution,the resultant force and its application point under non-limit state which considered the influence of wall deformation were deduced. The result of an example showed that the difference between the theoretical calculation value quantified by the method of effective area ratio of displacement and the measured value was small. The proposed formula well reflects the change of earth pressure with the wall displacement and is an effective extension of Coulumb′s theoretical formula.%经典土压力理论仅能计算平移模式挡墙的极限状态土压力。采用以主应力差表示的应力圆,根据应力路径三轴试验中得到的径向应力–应变关系,建立非极限状态下受位移影响的土体内摩擦角、墙土间摩擦角发挥值随位移的变化关系,并提出有效位移面积比方法将该关系量化至转动变位模式挡墙。在此基础上,应用水平层分析法和改进的库仑公式,推导出考虑挡墙变位影响的非极限土压力合力及其作用点位置、土压力分布计算式。研究表明:按有效位移面积比方法进行量化后,理论计算值与实测值相对误差

  12. 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)

  13. Relevance of balance measurement tools and balance training for fall prevention in older adults

    Directory of Open Access Journals (Sweden)

    Majumi M. Noohu, MPTh

    2014-06-01

    Full Text Available Approximately one in three older people fall each year owing to gait/balance disorder/weakness, the second leading cause of falls in older adults. This review evaluates the capability of different balance measurement tools to predict falls in the elderly, which are used routinely for assessing balance impairment. Balance measurement tools reviewed are the Timed Up and Go test, Berg Balance Scale, Tinetti Performance Oriented Mobility Assessment, Functional Reach Test, Clinical Test of Sensory Integration for Balance, and the postural sway measurements or center of pressure. The effect of balance training on the postural control mechanism and its efficacy in fall prevention in older adults were also reviewed. The current evidence is not conclusive enough to favor existing balance measurement tools and balance training implemented for fall prevention in older adults.

  14. Balanced Scorecard

    OpenAIRE

    Kytka, Roman

    2008-01-01

    V současnosti se podniky setkávají s řadou přístupů k řízení společností a velmi častými pojícími prvky bývají zejména náklady, efektivita a výkonnost. Z nepřeberné řady nástrojů k řízení společností určených tato práce blíže seznamuje s metodikou Balanced Scorecard (BSC), koncepčním rámcem ITIL a metodikou Cobit. Jednotlivě zde jsou představeny dílčí metodiky a rámce. Míra tohoto seznámení je úměrná potřebám práce, tzn. není cílem představit ITIL či Cobit úplně detailně. Naopak zde jsou podc...

  15. Hydrogeochemistry in soils and sediments in the area of the Lagoa Campestre lake (Salitre, MG, Brazil) : chemical balances of major and trace elements and dynamics of rare earth elements

    OpenAIRE

    Sondag, Francis; Soubiès, François; Fortune, J.P.; B. Dupré; Magat, P.; Melfi, A. (collab.)

    1997-01-01

    Study of the sediments filling the Lagoa Campestre peaty lake (Minas Gerais, Brazil) showed a high rare earth elements (REE) content, especially in phosphatic bottom beds (authigenic phosphates), whose fluctuations could be related to variations in the erosion conditions and the nature of the plant cover. In order to understand better the mode of complexation and transport of trace elements in this environment, a geochemical survey was undertaken of the waters of the area, both in surface str...

  16. Approximately-Balanced Drilling in Daqing Oilfield

    Institute of Scientific and Technical Information of China (English)

    Xia Bairu; Zheng Xiuhua; Li Guoqing; Tian Tuo

    2004-01-01

    The Daqing oilfield is a multilayered heterogeneous oil field where the pressure are different in the same vertical profile causing many troubles to the adjustment well drillings. The approximately-balanced drilling technique has been developed and proved to be efficient and successful in Daqing oilfield. This paper discusses the application of approximately-balanced drilling technique under the condition of multilayered pressure in Daqing oilfield, including the prediction of formation pressure, the pressure discharge technique for the drilling well and the control of the density of drilling fluid.

  17. Water and sodium balance in space

    DEFF Research Database (Denmark)

    Drummer, C; Norsk, P; Heer, M

    2001-01-01

    We have previously shown that fluid balances and body fluid regulation in microgravity (microG) differ from those on Earth (Drummer et al, Eur J Physiol 441:R66-R72, 2000). Arriving in microG leads to a redistribution of body fluid-composed of a shift of fluid to the upper part of the body...... and an exaggerated extravasation very early in-flight. The mechanisms for the increased vascular permeability are not known. Evaporation, oral hydration, and urinary fluid excretion, the major components of water balance, are generally diminished during space flight compared with conditions on Earth. Nevertheless......, cumulative water balance and total body water content are stable during flight if hydration, nutritional energy supply, and protection of muscle mass are at an acceptable level. Recent water balance data disclose that the phenomenon of an absolute water loss during space flight, which has often been reported...

  18. Origin of the change of the electrical and optical properties in shocked Al2O3 and prediction of an increase in electrical conductivity in MgSiO3 at pressure-temperature conditions of the Earth's D'' layer

    Science.gov (United States)

    He, L.; Tang, M. J.; Fang, Y.; Jing, F. Q.

    2008-08-01

    Shock-wave experiments of Al2O3 indicated the onset of an increase in electrical conductivity and observed the optical transparency loss at ~130 GPa. Here, based on first-principles calculations, we determine the pressure dependence of the band gap of perfect Al2O3 to 220 GPa, and investigate the optical absorption of Al2O3 without and with oxygen and aluminum vacancies within 220 GPa. Our results indicate that: 1) the onset of the conductivity increase is attributed to a band-gap decrease due to the Rh2O3(II)-CaIrO3 transition at ~130 GPa and ~1500 K; 2) this transition is not responsible for the transparency loss, but heterogeneous absorption in the visible-light region, induced by the +2 charge oxygen vacancy, should be a source of this phenomenon. The calculations of perfect MgSiO3, a material analogous to Al2O3, suggest that a perovskite to post-povskite transition in MgSiO3 at ~125 GPa and ~2500 K also yields a band-gap reduction. This causes an increase in electrical conductivity in MgSiO3 at pressure-temperature conditions of the Earth's D'' layer.

  19. 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

  20. Major Element Compositions and Rare—earth Element Abundaces of Cenozoic Basalts in Eastern China:Implications for a Pressure Control over LREE/HREE Fractionation in Continental Basalt

    Institute of Scientific and Technical Information of China (English)

    刘丛强; AKIMASAMASUDA; 等

    1992-01-01

    Major element compositions and rare-earth element (REE) and transition element(Ni,Cr and V) abundances have been determined on 44 basalt samples from eastern China.These basalts have SiO2 contents ranging from 38.63 to 55.24(wt.%),and Na2O+K2O from 3.1 to 9.4(wt.%).Ni and Cr abundances are largely variable,respectively falling in ranges 60-605 and 78-1150 ppm.REE abundances,especially light rare-earth elements(LREE), are highly variable.La/Sm and La/Yb ratios vary 2.8 to 7.6 and 1.8 to 8.1. Although the segregation mainly of olivine and clinopyroxene is requested to account for the vari-able and low MgO,CaO/Al2O3,Cr and Ni characteristic of these basalts studied here,the differ-ences in REE composition of the basalts are still related mainly to the partial melting process.Obvious varations in REE abundances could be principally attributed to the partial melting process.Obvious variations in REE abundances could be principally attributed to the partial melting processes that took place at different depths,in spite of some variations caused by the fractional crystallization processes.REE abundances and La/Sm and La/Yb ratios systematically decrease with increasing SiO2,which probably indicated that the basaltic magma derived from a deeper level has higher LREE and LREE/HREE ratios than that from a shallower level.As viewed from the fact that the DYb/DLa ratios of clinopyroxenes in the basaltic system increase with increasing pressure,the increase of LREE/HUEE ratios with increasing melting depth can be interpreted as the pressure dependence of bulk DHREE/DLREE ratios of silicate minerals,in addition to the pressure control over the melting degree.

  1. 土石坝心墙填土恒压吸湿变形试验研究%EXPERIMENTAL STUDY ON THE WETTING DEFORMATION OF THE SOIL USED IN THE CORE WALL OF EARTH-ROCK DAM UNDER CONSTANT PRESSURE

    Institute of Scientific and Technical Information of China (English)

    郭冲; 邱秀梅; 赵晓龙; 卞汉兵

    2013-01-01

    通过一维固结试验分析了各级压力下非饱和重塑土在加水饱和过程中的变形特征,结果显示不同压力下试件饱和过程的变形呈现出不同特征.试验结果如下:50 kPa压力下呈现出膨胀特征;100 kPa、150 kPa和200kPa压力下,呈现出先膨胀后压缩的特征,而且最终变形与加水前相比也各有不同;300kPa和400kPa压力下,试件压缩变形量明显增大.此种变形特征可能会导致土石坝心墙在蓄水过程中形成裂缝,从而为土石坝心墙发生水力劈裂破坏提供条件.%By using the conventional oedometer consolidation test, the deformation characteristics of unsaturated remolded soil under constant compression stresses subjected to wetting process were analyzed. The test result indicates that the deformation characteristics were different under different constant compression stresses. The test result is as follows; under the pressure of 50kPa the specimen was expansive; under the pressure of lOOkPa, 150kPa and 200kPa, the deformations had a transition from expansion to compression, and the final total deformations were respectively different from the deformations compared with prior to the saturation process; and under the pressure of 300kPa and 400kPa, the collapse was observed. The deformation characteristics may lead to cracks in the core of earth - rock fill dam which cause the hydraulic fracture.

  2. 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 ...

  3. Using earth-tide induced water pressure changes to measure in situ permeability: A comparison with long-term pumping tests

    Science.gov (United States)

    Allègre, Vincent; Brodsky, Emily E.; Xue, Lian; Nale, Stephanie M.; Parker, Beth L.; Cherry, John A.

    2016-04-01

    Good constraints on hydrogeological properties are an important first step in any quantitative model of groundwater flow. Field estimation of permeability is difficult as it varies over orders of magnitude in natural systems and is scale-dependent. Here we directly compare permeabilities inferred from tidal responses with conventional large-scale, long-term pumping tests at the same site. Tidally induced water pressure changes recorded in wells are used to infer permeability at ten locations in a densely fractured sandstone unit. Each location is either an open-hole well or a port in a multilevel monitoring well. Tidal response is compared at each location to the results of two conventional, long-term and large scale pumping tests performed at the same site. We obtained consistent values between the methods for a range of site-specific permeabilities varying from ˜10-15 m2 to 10-13 m2 for both open wells with large open intervals and multilevel monitoring well. We conclude that the tidal analysis is able to capture passive and accurate estimates of permeability.

  4. 主、被动土压区加固对地铁深基坑变形影响的数值分析%Numerical Analysis about Effect on Deformation Caused by Reinforcing Deep Foundation Pit of Metro Station at Passive or Active Earth Pressure Zone

    Institute of Scientific and Technical Information of China (English)

    侯新宇; 刘松玉; 童立元

    2012-01-01

    Adopting Hardening-Soil finite element model under the condition of soil mass unloading, three reinforcement models that causes the influences on deformation of the deep foundation pit of metro station were studied, including " reinforcement in passive zone" , " reinforcement in active zone " , "reinforcement in passive and active zone". The results show that the effects are considerable prominent for controlling the lateral and uplift deformations with "reinforcement in passive zone" and "reinforcement in passive and active zone". The "reinforcement in passive and active zone" and "reinforcement in active zone" can balance the earth pressure, improve the whole characters of retaining structure, and control the earth deformation behind foundation pit effectively. The best whole effect of reinforcement is obtained by "reinforcement in passive and active zone". Therefore, selecting the rational reinforcement models based on different geological conditions and deformation limits can effectively meet the requirements of pit safety and environment influencing, besides, save the engineering cost.%采用土体卸载条件下的HS( hardening-soil)有限元模型,分析“仅主动区加固”、“仅被动区加固”、“主被动区加固”等3种加固方式对地铁车站深基坑变形的影响.结果表明:“主被动区加固”和“仅被动区加固”控制基坑侧向变形及坑底隆起变形效果较为显著;“主被动区加固”和“仅主动区加固”能够均衡土压,提高支护结构整体性状,能够有效抑制基坑后土体变形.“主被动区加固”总体加固效果最优.因此,根据不同地质条件和基坑变形控制要求,选择合理的加固形式,既能保证基坑安全和环境影响的要求,又能降低造价.

  5. An Analog Earth Climate Model

    Science.gov (United States)

    Varekamp, J. C.

    2010-12-01

    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.

  6. Research and practice of water pressure balance and purification system in underwater protection works of White Crane Ridge Inscription%白鹤梁水下保护工程平压净水系统研究与实践

    Institute of Scientific and Technical Information of China (English)

    王环武; 韩建成; 龚斌

    2014-01-01

    三峡库区的白鹤梁水下题刻保护工程采用“无压容器”的概念建造,实现该原理的关键设备为平压净水系统。通过选择廊道输水方式,并设计合理的水压平衡程序、充水置换程序、封闭循环程序等,实现了保护体内外水压差基本为零,且水的浊度始终达标。该系统已安全运行5 a,从而证明前期的设计思路、方法及模拟试验成果均是可行和可靠的。%The concept of "non-pressure vessel" was adopted to build the underwater protection works of White Crane Ridge Inscription, and the water pressure balance and purification system is a key equipment. For realizing balance of water pressure in the protection works and maintaining of water clear, a corridor water transferring solution is adopted, and several procedures are designed, including pressure balance procedure, water filling and replacement procedure, closed cycle procedure, et al. The system has been operated safely for 5 years, so it verifies the correctness and reliability of the previous design ideas, methodology as well as simulation tests.

  7. Analysis on earth pressure distribution of liquescent soil foundation reinforced by composite pile%复合桩加固液化土土压力分布分析

    Institute of Scientific and Technical Information of China (English)

    赵军永; 牛琪瑛; 刘峰

    2014-01-01

    In order to study the mechanism of using composite pile to reinforce liquescent soil foun-dation, three models, including un-reinforced foundation, foundation reinforced by gravel pile and steel pipe pile, foundation reinforced by cement pile and steel pipe pile were prepared, and simula-ted seismic load was applied by the shaking table test. Pressure-time curve of excess pore water in different depth and pressure-time curve of earth in different depth were sorted out from the data col-lected by the data acquisition system in the three models during the vibration of foundations. The test results show that the pressure of excess pore water of the un-reinforced and foundation reinforced by cement pile and steel pipe pile was increased to the peak around 7 kPa and the pressure remained 7 kPa until the end of the test. The pressure of excess pore water of the foundation reinforced by gravel pile and steel pipe pile was increased to the peak around 5 kPa and it was reduced to about 2. 5 kPa at the end of the test. The gravel pile plays a role of dissipating the pressure of excess pore water. The earth pressure of the un-reinforced and foundation reinforced by cement pile and steel pipe pile was increased to the peak around 105 kPa, then reduced by about 35 kPa. The earth pres-sure of foundation reinforced by gravel pile and steel pipe pile is equal to the peak about 110 kPa.Soil strength and the bearing capacity of composite foundation are high. Therefore, using the founda-tion reinforced by gravel pile and steel pipe pile can effectively resist soil liquefaction and improve foundation bearing capacity. The research plays a reference role for the promotion of gravel pile and rigid pile reinforced liquefied soil in engineering.%为进一步研究复合桩加固液化土地基机理,制备未加固、碎石桩与钢管桩、水泥土桩与钢管桩复合加固三种地基模型,模拟地震荷载,进行振动台试验。通过数据采集系统采集三种模型数

  8. Dizziness and Balance

    Science.gov (United States)

    AUDIOLOGY Dizziness and Balance Inform ation Seri es Our balance system helps us walk, run, and move ... known as nystagmus) • Complaints of vertigo or dizziness Audiology Information Series © ASHA 2015 10802 • Balance dysfunction • Difficulty ...

  9. 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.

  10. 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

  11. Greenland ice sheet mass balance: a review

    DEFF Research Database (Denmark)

    Khan, Shfaqat Abbas; Aschwanden, Andy; Bjørk, Anders A.;

    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...

  12. 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…

  13. 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…

  14. 地铁区间隧道穿越粉细砂地层土压平衡盾构施工技术%Earth-Pressure-Balanced Shield Construction Techniques for Subway Tunnels in the Fine Sand Stratum

    Institute of Scientific and Technical Information of China (English)

    肖昱

    2015-01-01

    石家庄市城市轨道交通1号线体育场站~北宋站区间隧道穿越粉细砂地层,施工采用土压平衡盾构掘进技术,对始发洞口进行了双管旋喷桩加固,掘进过程中优化了盾构推进速度、土仓压力、出土量、推力及注浆压力等主要技术参数,保证了施工安全,区间隧道顺利贯通;采用同步注浆和二次注浆措施及优化的掘进施工参数控制了掌子面的稳定和地表沉降.工程实践证明土压平衡盾构也适用于粉细砂地层的区间隧道施工.

  15. 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.

  16. Rare earths

    International Nuclear Information System (INIS)

    General mineralogical-geochemical and analytical characteristics of (lanthanides and yttrium) are presented. It is pointed out that individual RE in complex chemical composition samples are successfully determined by physical methods of the analysis (emission spectral method, spark mass spectrometry method, neutron + activation analysis). RE sum determination is performed by spectrophotometric titrimetric or gravimetric methods. Principal methods of RE separation and concentration, methods of analytical samples dissolution are considered. Detailed descriptions of some specific techniques of determining rare earths in rocks, ores and minerals are presented

  17. A climatic thermostat making Earth habitable

    OpenAIRE

    Ditlevsen, Peter D.

    2005-01-01

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

  18. 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.

  19. Role of the Earth's rotation in global geodynamics

    Science.gov (United States)

    Pavlenkova, N.

    2009-04-01

    degasification of the Earth (the fluids advection) and changes in the Earth rotation. At formation of the core there was the Earth's expansion and was formed system of global lineaments and the Pacific ring. Bipolar convection in the core has created a magnetic field and the increased advection of deep fluids in the southern hemisphere. The last promoted formation of thick continental lithosphere in this hemisphere in Archean-Proterozoi. This thick lithosphere has led to asymmetry of the planet and to relative displacement of the mass centers of the Earth's spheres. It produced high pressure between the spheres (Barkin, 2002) and could have initiated their relative displacements. As a uniform asthenosphere does not exist and the continents have deep roots such displacements were most probable on a surface of a liquid outer core. The marked mass centre dislocation has caused the turning of the mantle around the core with movement of the continental hemisphere from South Pole to the equator. It corresponds to the data on movement of paleomagnetic and paleoclimate poles that took place in Paleozoic era. The rotation of the mantle around the core passed non-uniformly: the tidal forces connected to periodic change of Earth's rotation axis position in system the Earth-Lund-Sun (Avsyuk, 1996) were imposed on the basic moving forces restoring the mass center balance. The periodic displacements of the mantle created conditions for alternation of tectonic activity epochs. Rotation of the mantle around the core created a new nonequilibrium system. Therefore in Mesozoic era a new stage begins: an expansion of the southern hemisphere which radius is now bigger, than the northern one. Such expansion created the regular system of the mid-oceanic ridges forming a ring around Antarctica with the symmetric Mid-Atlantic, Indian and Pacific ridges. Supposedly at the last stage the formation of the continent on South Pole (Antarctica) and destruction of a continental crust on the northern hemisphere

  20. 节律性压力波对家犬气道黏蛋白分泌平衡的影响及其机制%Effect of rhythmic pressure waves on balancing airway basic mucus secretion in dogs

    Institute of Scientific and Technical Information of China (English)

    刘诗兰; 尤列·皮尔曼; 维克多·科罗索夫; 周向东

    2013-01-01

    group C:the tension-sensitive cation channel (TRPV) 4 blocker Ruthenium Red (RR) was injected in advance, and ventilated as in group A. In group D:TRPV4 blocker RR was injected ifrstly, and then ventilated as in group B. Atfer 12 h ventilation, we collected bronchoalveolar lavage lfuid (BALF), tested MUC (2, 5AC, 5B) protein content by ELISA, and detected the transcription of MUC (2, 5AC, 5B) mRNA of bronchial lung tissue by RT-PCR . Results:Compared with the normal ventilation (A2) group, the protein level of MUC of excessive ventilation (B2) group was significantly higher, mainly MUC5AC (P<0.05);compared with the normal ventilation (A1) group, the protein level of MUC of no ventilation (B1) group was signiifcantly decreased (P<0.05). Atfer pretreatment with RR, the MUC protein level of group C1, C2 were signiifcantly lower than that of group A1, A2 (P<0.05);the MUC protein level of group B2were significantly lower than that of group D2 (P<0.05). The MUC (2, 5AC and 5B) mRNA level was higher in excessive ventilation group (B2) than in normal ventilation group (A2). Atfer pretreatment with RR, in comparison with group A1, A2, the MUC (2, 5AC and 5B) mRNA level of group C1, C2 declined;in comparison with group B2, the MUC (2, 5AC and 5B) mRNA level of group D2 declined. Conclusion:Rhythmic pressure waves may regulate and balance basic airway mucin secretion through activating the TRPV4 channel in dogs.

  1. Effect of Aquatic Immersion on Static Balance

    OpenAIRE

    Louder, Talin J.

    2013-01-01

    Objective To quantitatively assess measures of static balance and limits of stability (LOS) in an aquatic environment compared to on land. Methods Fifteen healthy, young adults (23 + or - 2 years) performed 90 s static balance trials on land and aquatic immersion at two different depths (greater trochanter, xiphoid process). Measures of 95% ellipse area and center of pressure (CoP) mean velocity were computed from the force data. Additionally, participants completed a visual analog scale (VAS...

  2. Human Balance System

    Science.gov (United States)

    ... Rated Nonprofit! Volunteer. Donate. Review. The Human Balance System Good balance is often taken for granted. Good ... soft, slippery, or uneven). Input from the vestibular system Sensory information about motion, equilibrium, and spatial orientation ...

  3. Balanced Scorecard voor inkoop

    NARCIS (Netherlands)

    Honing, van der R.; Schotanus, F.

    2003-01-01

    Een Balanced Scorecard kan ontwikkeld worden voor de hele organisatie, maar ook voor onderdelen daarvan. In dit artikel wordt ingegaan op de ontwikkeling van een Balanced Scorecard voor de inkoopafdeling

  4. Polarization-balanced beamsplitter

    Science.gov (United States)

    Decker, D.E.

    1998-02-17

    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.

  5. Mass balance, meteorological, and runoff measurements at South Cascade Glacier, Washington, 1992 balance year

    Science.gov (United States)

    Krimmel, R.M.

    1993-01-01

    Values of winter snow accumulation and summer snow, firn, and ice ablation were measured at South Cascade Glacier, WA, to determine the winter and net balance for the 1992 balance year. The 1992 winter balance, averaged over the glacier, was 1.91 m, and the net balance was -2.01 m. This extremely negative balance continued a trend of negative balance years beginning in 1977. Air temperature (at 1,615 m and 1,867 m), barometric pressure, precipitation, and runoff from this glacier basin and an adjacent non-glacierized basin were also continuously measured. This report makes all these data, in tabular, graphical, and machine-readable forms, available to users.

  6. A preliminary study on pressure-plate evaluation of forelimb toe-heel and mediolateral hoof balance on a hard vs. a soft surface in sound ponies at the walk and trot

    NARCIS (Netherlands)

    Oosterlinck, M; Royaux, E; Back, W; Pille, F

    2014-01-01

    REASONS FOR PERFORMING STUDY: Thus far, pressure-plate analysis has been limited to measurements on a hard surface, whereas equine athletes routinely perform on a deformable substrate. OBJECTIVES: To explore pressure-plate analysis on arena footing. STUDY DESIGN: Nonrandomised crossover study using

  7. Accounting on Material Balance of Hydroprocessing Unit by Solubility Equilibrium in High Pressure Separator%利用高分溶解平衡核算加氢装置物料平衡的探索

    Institute of Scientific and Technical Information of China (English)

    牛世坤; 李士才; 徐大海

    2013-01-01

    针对目前实验室测定装置物料平衡方法中存在的高分各种低分子烃类溶解度不同对物料平衡的影响,改变测定装置物料平衡的流程,利用反应物料在高分溶解后废氢中低分子烃类含量,结合 HYSYS 软件中Adjust功能,较为准确核算装置物料平衡,还原加氢反应本身的反应结果。%In view of the effects of different solubility of low molecular hydrocarbons in HP separator on the material balance in the unit material balance measuring method of the current lab, the material balance measuring process was changed, using the low molecular hydrocarbon concentration in the waste H2 after HP solubility and combining with the Adjust function in HYSYS software could account the unit material balance more accurately and restore hydrogenation reaction results.

  8. Keeping Earth at work: Using thermodynamics to develop a holistic theory of the Earth system

    Science.gov (United States)

    Kleidon, Axel

    2010-05-01

    The Earth system is unique among terrestrial planets in that it is maintained in a state far from thermodynamic equilibrium. Practically all processes are irreversible in their nature, thereby producing entropy, and these would act to destroy this state of disequilibrium. In order to maintain disequilibrium in steady state, driving forces are required that perform the work to maintain the Earth system in a state far from equilibrium. To characterize the functioning of the Earth system and the interactions among its subsystems we need to consider all terms of the first and second law of thermodynamics. While the global energy balance is well established in climatology, the global entropy and work balances receive little, if any, attention. Here I will present first steps in developing a holistic theory of the Earth system including quantifications of the relevant terms that is based on the first and second laws of thermodynamics. This theory allows us to compare the significance of different processes in driving and maintaining disequilibrium, allows us to explore interactions by investigating the role of power transfer among processes, and specifically illustrate the significance of life in driving planetary disequilibrium. Furthermore, the global work balance demonstrates the significant impact of human activity and it provides an estimate for the availability of renewable sources of free energy within the Earth system. Hence, I conclude that a holistic thermodynamic theory of the Earth system is not just some academic exercise of marginal use, but essential for a profound understanding of the Earth system and its response to change.

  9. A method to estimate the composition of the bulk silicate Earth in the presence of a hidden geochemical reservoir

    Science.gov (United States)

    Korenaga, Jun

    2009-11-01

    The possibility of a hidden geochemical reservoir in the deep mantle has long been debated in geophysics and geochemistry, because of its bearings on the structure of the core-mantle boundary region, the origin of hotspots, the style of mantle convection, the history of the geomagnetic field, and the thermal evolution of Earth. The presence of such hidden reservoir, however, may invalidate existing models for the composition of the bulk silicate Earth because these models invariably assume that major chemical differentiation in the mantle follows the compositional trend exhibited by upper-mantle rocks. This article presents a new method to estimate the composition of the bulk silicate Earth by explicitly taking into account the possibility of a hidden reservoir. This geochemical inference is formulated as a nonlinear inverse problem, for which an efficient Markov chain Monte Carlo algorithm is developed. Inversion results indicate that the formation of a hidden reservoir, if any, took place at low pressures probably within the first 10 Myr of the history of the solar system and was subsequently lost from the Earth by impact erosion. The global mass balance of the bulk silicate Earth is revisited with the inversion results, and the depletion of highly incompatible elements in the present-day Earth is suggested to be moderate.

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

    Science.gov (United States)

    Khachay, Yurie; Anfilogov, Vsevolod

    2013-04-01

    For a long time as a most convenient had been the model of mega impact in which the early forming of the Earth's core and mantle had been the consequence of formed protoplanet collision with the body of Mercurial mass. But all dynamical models of the Earth's accumulation and the estimations after the Pb-Pb system, lead to the conclusion that the duration of the planet accumulation was about 1 milliard years. But isotopic results after the W-Hf system testify about a very early (5-10) million years, dividing of the geochemical reservoirs of the core and mantle. In [1,3] it is shown, that the account of energy dissipating by the decay of short living radioactive elements and first of all Al,it is sufficient for heating even small bodies with dimensions about (50-100) km up to the iron melting temperature and can be realized a principal new differentiation mechanism. The inner parts of the melted preplanets can join and they are mainly of iron content, but the cold silicate fragments return to the supply zone. Only after the increasing of the gravitational radius, the growing area of the future core can save also the silicate envelope fragments. All existing dynamical accumulation models are constructed by using a spherical-symmetrical model. Hence for understanding the further planet evolution it is significant to trace the origin and evolution of heterogeneities, which occur on the planet accumulation stage. In that paper we are modeling distributions of temperature, pressure, velocity of matter flowing in a block of 3D- spherical body with a growing radius. The boundary problem is solved by the finite-difference method for the system of equations, which include equations which describe the process of accumulation, the Safronov equation, the equation of impulse balance, equation Navier-Stocks, equation for above litho static pressure and heat conductivity in velocity-pressure variables using the Businesque approach. The numerical algorithm of the problem solution in

  11. Synchrotron radiation - Applications in the earth sciences

    Science.gov (United States)

    Bassett, W. A.; Brown, G. E., Jr.

    Synchrotron-radiation sources and their characteristics are overviewed along with recent synchrotron-based research on earth materials and future earth-science applications utilizing the next generation of synchrotron-radiation sources presently under construction. Focus is placed on X-ray scattering studies of earth materials (crystalline and noncrystalline) under ambient conditions, diffraction studies of earth materials at high pressures and/or temperatures, spectroscopic studies, primarily X-ray absorption spectroscopy, and spatially resolved X-ray fluorescence studies of compositional variations in earth materials. It is noted that other synchrotron-based methods, such as X-ray tomography and topography may become important in characterizing earth materials, while soft X-ray/vacuum ultraviolet radiation from synchrotron sources can be applied to problems involving the structural environments of low-atomic-number elements and the characterization of surface reactions of minerals with liquids and gases.

  12. The Effect of Balance Acupuncture on“Jiangtang point”for the Blood Pressure of Patients with Type 2 Diabetes Mellitus%针刺降糖穴对2型糖尿病血压的影响研究

    Institute of Scientific and Technical Information of China (English)

    王文远; 马忠立; 张利芳

    2014-01-01

    Objective :To observe the clinical efficacy of balance acupuncture on “Jiangtang point”for blood pressure and heart rate of patients with type 2 diabetes mellitus .Methods :60 patients with type 2 diabetes mellitus were acu‐punctured on“Jiangtang point”for 3 weeks .During the treatment ,we recorded the level change of blood glucose ,urine glucose and the clinical symptoms as well as the systolic pressure ,diastolic pressure ,heart rate and pulse and so on .Sta‐tistical analysis was performed with the use of CHISS software .Results:The treatment of balance acupuncture on“Jian‐gtang point”can not only reduce the level of blood glucose ,urine glucose and the clinical symptoms but also the systolic pressure ,diastolic pressure ,heart rate and pulse of the patients during the treatment for 3 weeks (P<0 .001) .Conclu‐sion:The treatment of balance acupuncture on“Jiangtang point”has an effective improvement on the hypertension while reducing the level of blood glucose ,urine glucose for the patients with type 2 diabetes mellitus .%目的:观察平衡针灸降糖穴对2型糖尿病患者的血压和心率的影响。方法:对60例2型糖尿病患者针刺降糖穴治疗3周,对其血糖、尿糖及其临床症状变化记录的同时,记录收缩压、舒张压、心率和脉搏等变化,采取CHISS统计软件进行统计分析。结果:针刺降糖穴不仅能够降低2型糖尿病患者血糖、尿糖和改善临床症状,同时可以降低收缩压、舒张压和心率,治疗3周前、后有明显差异( P<0.001)。结论:平衡针灸降糖穴对2型糖尿病血糖、尿糖降低的同时对高血压有明显改善。

  13. Models of the Earth's Core.

    Science.gov (United States)

    Stevenson, D J

    1981-11-01

    Combined inferences from seismology, high-pressure experiment and theory, geomagnetism, fluid dynamics, and current views of terrestrial planetary evolution lead to models of the earth's core with the following properties. Core formation was contemporaneous with earth accretion; the core is not in chemical equilibrium with the mantle; the outer core is a fluid iron alloy containing significant quantities of lighter elements and is probably almost adiabatic and compositionally uniform; the more iron-rich inner solid core is a consequence of partial freezing of the outer core, and the energy release from this process sustains the earth's magnetic field; and the thermodynamic properties of the core are well constrained by the application of liquid-state theory to seismic and laboratory data. PMID:17839632

  14. Early Earth differentiation [rapid communication

    Science.gov (United States)

    Walter, Michael J.; Trønnes, Reidar G.

    2004-09-01

    The birth and infancy of Earth was a time of profound differentiation involving massive internal reorganization into core, mantle and proto-crust, all within a few hundred million years of solar system formation ( t0). Physical and isotopic evidence indicate that the formation of iron-rich cores generally occurred very early in planetesimals, the building blocks of proto-Earth, within about 3 million years of t0. The final stages of terrestrial planetary accretion involved violent and tremendously energetic giant impacts among core-segregated Mercury- to Mars-sized objects and planetary embryos. As a consequence of impact heating, the early Earth was at times partially or wholly molten, increasing the likelihood for high-pressure and high-temperature equilibration among core- and mantle-forming materials. The Earth's silicate mantle harmoniously possesses abundance levels of the siderophile elements Ni and Co that can be reconciled by equilibration between iron alloy and silicate at conditions comparable to those expected for a deep magma ocean. Solidification of a deep magma ocean possibly involved crystal-melt segregation at high pressures, but subsequent convective stirring of the mantle could have largely erased nascent layering. However, primitive upper mantle rocks apparently have some nonchondritic major and trace element refractory lithophile element ratios that can be plausibly linked to early mantle differentiation of ultra-high-pressure mantle phases. The geochemical effects of crystal fractionation in a deep magma ocean are partly constrained by high-pressure experimentation. Comparison between compositional models for the primitive convecting mantle and bulk silicate Earth generally allows, and possibly favors, 10-15% total fractionation of a deep mantle assemblage comprised predominantly of Mg-perovskite and with minor but geochemically important amounts of Ca-perovskite and ferropericlase. Long-term isolation of such a crystal pile is generally

  15. 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

  16. 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.

  17. The Balanced Company

    DEFF Research Database (Denmark)

    through control or trust. Human resource specialists need to make balanced decisions about how to design tasks and jobs in order to make them attractive as well as motivating. Marketers need to make balanced decisions about how to market products in the light of what is now important in consumers...... 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 to achieve goals......' 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 involved in both...

  18. Rare Earth Market Review

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Oversupply of rare earths led to the significant price drop of rare earth mineral products and separated products in Chinese domestic market. To stabilize the price, prevent waste of resources, further improve regulation capability on domestic rare earth market and rare earth price and maintain sustaining and healthy development of rare earth industry, partial rare earth producers in Baotou and Jiangxi province projected to cease the production for one month.

  19. The oxygen and carbon dioxide balance in the earth's atmosphere

    Science.gov (United States)

    Johnson, F. S.

    1975-01-01

    The oxygen-carbon dioxide cycle is described in detail, and steps which are sensitive to perturbation or instability are identified. About half of the carbon dioxide consumption each year in photosynthesis occurs in the oceans. Phytoplankton, which are the primary producers, have been shown to assimilate insecticides and herbicides. The impact of such materials on phytoplankton photosynthesis, both direct and as the indirect result of detrimental effects higher up in the food chain, cannot be assessed. Net oxygen production is very small in comparison with the total production and occurs almost exclusively in a few ocean areas with anoxic bottom conditions and in peat-forming marshes which are sensitive to anthropogenic disturbances. The carbon dioxide content of the atmosphere is increasing at a relatively rapid rate as the result of fossil fuel combustion. Increases in photosynthesis as the result of the hothouse effect may in turn reduce the carbon dioxide content of the atmosphere, leading to global cooling.

  20. Cyclical budget balance measurement

    OpenAIRE

    C. AUDENIS; C. PROST

    2000-01-01

    Government balances are often adjusted for changes in economic activity in order to draw a clearer picture of the underlying fiscal situation and to use this as a guide to fiscal policy analysis. International organisations estimate the cyclical component of economic activity by the current level of the output gap. Using elasticities of tax and public expenditures to GDP, they compute the cyclical part of budget balance. The structural budget balance is defined as the remainder. Our approach ...

  1. Regimes of validity for balanced models

    Science.gov (United States)

    Gent, Peter R.; McWilliams, James C.

    1983-07-01

    Scaling analyses are presented which delineate the atmospheric and oceanic regimes of validity for the family of balanced models described in Gent and McWilliams (1983a). The analyses follow and extend the classical work of Charney (1948) and others. The analyses use three non-dimensional parameters which represent the flow scale relative to the Earth's radius, the dominance of turbulent or wave-like processes, and the dominant component of the potential vorticity. For each regime, the models that are accurate both at leading order and through at least one higher order of accuracy in the appropriate small parameter are then identified. In particular, it is found that members of the balanced family are the appropriate models of higher-order accuracy over a broad range of parameter regimes. Examples are also given of particular atmospheric and oceanic phenomena which are in the regimes of validity for the different balanced models.

  2. 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

  3. Determining the necessary conditions for Martian cloud formation: Ice nucleation in an electrodynamic balance (EDB)

    Science.gov (United States)

    Berlin, S.; Bauer, A. J.; Cziczo, D. J.

    2013-12-01

    The Martian atmosphere contains water ice clouds similar to Earth's cirrus clouds. These clouds influence the atmospheric temperature profile, alter the balance of incoming and outgoing radiation, and vertically redistribute water and mineral dust. Extrapolations of classical heterogeneous nucleation theory from Earth-like conditions to colder temperature and lower pressure regimes present in extraterrestrial atmospheres may be inaccurate, and thus hydrological models describing these regimes could lack physical meaning. In this project, we use an electrodynamic balance (EDB) to levitate individual aerosol particles and study their freezing properties. We test previously characterized aerosols such as Arizona Test Dust (ATD) and sodium chloride (NaCl). Then, we examine the less well-studied Mojave Mars Simulant (MMS) dust, which mimics the composition and size of dust particles found in the Martian atmosphere. A relative humidity, temperature, and inert atmosphere are utilized to emulate conditions found in the Martian atmosphere. We will discuss the supersaturations under which heterogeneous ice nucleation occurs on surrogate Martian ice nuclei at various temperatures.

  4. Procedure for Balancing an Air Distribution System with Decentralised Fans

    DEFF Research Database (Denmark)

    Gunner, Amalie; Hultmark, Göran; Vorre, Anders;

    2015-01-01

    This paper presents results from an on-going project concerning new design procedures for mechanical ventilation systems with low energy use. Conventional constant air volume (CAV) systems are usually balanced using flat plate dampers. The purpose of using balancing dampers is to intentionally...... flawed. This paper presents a new procedure for balancing of CAV systems in combination with decentralised fans. The new system was based on replacing the balancing dampers with decentralised fans. By replacing the balancing dampers with decentralised fans, airflows can be balanced by adjusting the speed...... of the fans. In conventional air distribution systems the fan provides the necessary pressure to overcome the resistance in the branch with the highest pressure resistance. This gives an unnecessary overpressure in the remaining branches that does not provide any useful purpose. In order to decrease the fan...

  5. 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…

  6. Conclusion: The balanced company

    DEFF Research Database (Denmark)

    Scheuer, John Damm; Jensen, Inger

    2013-01-01

    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....

  7. Leadership: A Balancing Act

    Science.gov (United States)

    Hines, Thomas E.

    2011-01-01

    Maintaining balance in leadership can be difficult because balance is affected by the personality, strengths, and attitudes of the leader as well as the complicated environment within and outside the community college itself. This article explores what being a leader at the community college means, what the threats are to effective leadership, and…

  8. 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 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 ongoing process of balancing the relation between trust and control. Second, taking the departure in the recent conceptualization of the balance between trust and control as an interactive process I discuss the challenges for management in handling this more subtle balancing of trust and control...

  9. Rare Earth Resolution

    Institute of Scientific and Technical Information of China (English)

    Mei Xinyu

    2012-01-01

    BEFORE the early 1970s, China had no rare earth exports, and the world rare earth market was dominated by the United States, Europe and Japan. In the 1970s, China began to enter the world rare earth market and its share has picked up sharply in the following decades. Today, having the monopoly over global rare earth production, China must improve the benefits from rare earth production, not only from producing individual rare earth products, but also from mastering the intensive processing of rare earth products.

  10. Pipe Construction of Balance of 1 000 MW Pressurized Water Reactor Nuclear Power Plant%1000MW压水堆核电站辅助设施管道施工

    Institute of Scientific and Technical Information of China (English)

    廖建华

    2011-01-01

    主要探讨了核电站辅助设施(balance of the plant,BOP)管道施工中出现的一些技术问题,如施工质量的可追溯性、共用支架防变形、电抛光管内部的洁净控制、沟槽式管件的应用等,并结合实际制订了相应的技术措施.这些措施通过现场的实际操作检验,证实了简单、有效,为后续核电BOP管道施工提供了借鉴.

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

    Science.gov (United States)

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

    2007-12-01

    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.

  12. Blood pressure

    Science.gov (United States)

    ... the walls of the arteries is called blood pressure. Blood pressure is measured both as the heart contracts, which ... as it relaxes, which is called diastole. Normal blood pressure is considered to be a systolic blood pressure ...

  13. 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.

  14. 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

  15. Chance for balance

    OpenAIRE

    Sævild, Katariina; Skov Sørensen, Katrine; Kildahl Lauritsen, Louise; Fuglsang, Sofie Olivia; Arnbjerg, Stine Høegh

    2015-01-01

    This project investigates how (im) balance between family and career influences Danish women's desire to have children. In order to answer this question, we have chosen to use qualitative method and our analysis is based on two semi-structured research interviews with two chosen women. Thus these women’s definition of balance and their view on children define the project. We have chosen to use of work-life balance theories, Thomas Hoejrup’s lifeform-analysis and Anthony Giddens’ theories ...

  16. 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

  17. Field Aligned Currents Derived from Pressure Profiles Obtained from TWINS ENA Images

    Science.gov (United States)

    Wood, K.; Perez, J. D.; McComas, D. J.; Goldstein, J.; Valek, P. W.

    2015-12-01

    Field aligned currents (FACs) that flow from the Earth's magnetosphere into the ionosphere are an important coupling mechanism in the interaction of the solar wind with the Earth's magnetosphere. Assuming pressure balance along with charge conservation yields an expression for the FACs in terms of plasma pressure gradients and pressure anisotropy. The Two Wide-Angle Imaging Neutral Atom Spectrometers (TWINS) mission, the first stereoscopic ENA magnetospheric imager, provides global images of the inner magnetosphere from which ion pressure distributions and pressure anisotropies can be obtained. Following the formulations in Heineman [1990] and using results from TWINS observations, we calculate the distribution of field aligned currents for the 17-18 March 2015 geomagnetic storm in which extended ionospheric precipitation was observed. Initial results for the field aligned currents will be generated assuming an isotropic pitch angle distribution. Global maps of field aligned currents during the main and recovery phase of the storm will be presented. Heinemann, H. (1990), Representations of Currents and Magnetic Fields in Anisotropic Magnetohydrostatic Plasma, J. Geophys. Res., 95, 7789.

  18. Balance Disorders (For Parents)

    Science.gov (United States)

    ... usually used on infants and young children. electronystagmogram (ENG). To assess balance, electrodes are placed around the ... videonystagmography (VNG). This test is similar to an ENG, only the child has to focus on the ...

  19. Keeping Your Balance

    Science.gov (United States)

    ... or problems with balance. Sometimes your doctor or physical therapist can reposition the crystals in your ear and ... Adherence Calcium/Vitamin D Nutrition Overall Health Fractures/Fall Prevention Exercise/Safe Movement Safe Movement & Exercise Videos ...

  20. 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.)

  1. 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.)

  2. Detailed balance and entanglement

    International Nuclear Information System (INIS)

    We study a connection between quantum detailed balance, which is a concept of importance in statistical mechanics, and entanglement. We also explore how this connection fits into thermofield dynamics. (paper)

  3. Balance costs for windpower

    OpenAIRE

    Skaflestad, Stig

    2009-01-01

    Wind power scheduling is subject to high forecast uncertainty compared to the dominant Norwegian energy source, hydro power. The regulating market, also known as the balance market, is a market solution for optimal operation of the Nordic power system, putting a price on schedule deviations. Schedules, or production/consumption plans, are collected daily, 12 hours prior to delivery by the system operator Statnett. Wind power is especially vulnerable to balance costs due to the relatively high...

  4. Selectively Balancing Unit Vectors

    OpenAIRE

    Blokhuis, Aart; Chen, Hao

    2016-01-01

    A set $U$ of unit vectors is selectively balancing if one can find two disjoint subsets $U^+$ and $U^-$, not both empty, such that the Euclidean distance between the sum of $U^+$ and the sum of $U^-$ is smaller than $1$. We prove that, to guarantee a selectively balancing set, $n \\log n$ unit vectors suffice for sufficiently large $n$, but $\\tfrac{1}{23} n \\log n$ unit vectors won't be enough for infinitely many $n$.

  5. 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…

  6. Greenland Ice Sheet Mass Balance

    Science.gov (United States)

    Reeh, N.

    1984-01-01

    Mass balance equation for glaciers; areal distribution and ice volumes; estimates of actual mass balance; loss by calving of icebergs; hydrological budget for Greenland; and temporal variations of Greenland mass balance are examined.

  7. 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...

  8. 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.

  9. Thermodynamics of the Earth

    Energy Technology Data Exchange (ETDEWEB)

    Stacey, Frank D [CSIRO Exploration and Mining, PO Box 883, Kenmore, Qld. 4069 (Australia)], E-mail: Frank.Stacey@csiro.au

    2010-04-15

    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 10{sup 12} 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 (>10{sup 4} : 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

  10. 采用球面静压轴承的大型水轮机转轮静平衡试验方法%Method of Static Balancing Test of the Large Water Turbine Wheel with Sphere Static-Pressure Bearing

    Institute of Scientific and Technical Information of China (English)

    马强

    2012-01-01

    提出一种采用球面静压轴承的大型混流式水轮机转轮静平衡试验方法。该方法可以直观地反应出转轮不平衡方位,通过简单计算即可准确地得到转轮的不平衡角度和不平衡重量,并可通过配重对整个试验过程进行验证,具有操作简单、直观、摩擦系数小、试验精度高、重复性好等优点。%The method of static balancing test of large water turbine wheel with sphere static-pressure bearing is put forward, which could reflect the imbalance position of the wheel directly and show the imbalance angle and weight of the wheel through simple calculation. In addition, the whole test could be verified with balance weight. The method features simplicity, small fi'ictional factor, high test precision and good repeatability.

  11. 足底压力式步态分析中痉挛型脑瘫儿童的平衡能力特征%Balancing characteristics of children with spastic cerebral palsy during gait measurement using plantar pressure gait analysis system

    Institute of Scientific and Technical Information of China (English)

    李海; 周安艳

    2009-01-01

    目的:临床上坐位、站立位的平衡测试常利用平衡仪来进行,但由于平衡仪足踏板的限制,无法对脑性瘫痪(脑瘫)患儿步行时动态连续步行周期的平衡能力进行测试.文章利用足底压力式步态分析技术,观察痉挛型脑瘫儿童步行时在平衡能力方面的特征.方法:选择具有正常步行能力的健康儿毫78例作为正常儿童组,另外选择2004 05/2007-05在深圳市儿童医院康复科日间病房住院治疗的脑瘫患儿25例作为脑瘫儿童组.利用足底压力式步态分析系统,对2组对象分别进行足底压力式步态分析,记录2组儿童步行时的足底压力数据.观测指标分为量化指标和直观压力图.量化指标包括步频、步态周期时间、步态周期各时相的绝对对称性指标等参数.直观压力图包括动态足底压力图以及足底压力重心偏移轨迹图.结果:与正常儿童组相比,脑瘫儿童组步频较小,步态周期时间较长(P<0.01).脑瘫儿童组单足支撑期、摆动期、双足支撑期、步态周期时间的绝对对称性指标均大于正常儿童组(P<0.05).脑瘫儿童步行时双足的足底压力图的对称性、重复性较正常儿童差;重心偏移轨迹图不能形成左右对称的蝴蝶状图形.结论:痉挛型脑瘫儿童步行时,步态周期各时相均存在对称性下降的情况.足底压力式步态分析技术能有效地应用于痉挛型脑瘫儿童步态的平衡能力评估.%OBJECTIVE: Usually, the balance tests of sitting and standing position are performed by balancing instruments clinicalty, but because of the restriction of foot pedal, this kind of instruments cannot measure balancing ability in continuous dynamic gait cycles in gait of cerebral palsy children. Using plantar pressure gait analysis system, this study sought to study balance characteristics in gait of children with spastic cerebral palsy.METHODS: A total of 78 healthy children served as normal control group, and

  12. 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

  13. Postural balance in low back pain patients

    DEFF Research Database (Denmark)

    Maribo, Thomas; Stengaard-Pedersen, Kristian; Jensen, Lone Donbæk;

    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......P) on a force platform. Portable force platforms might be of clinical relevance, but their reliability for LBP patients in a clinical setting has not been demonstrated. As LBP patients are more dependent on vision compared to healthy controls, the ratio of tests performed with eyes open and eyes closed (Romberg...... Ratio) might be of clinical interest. This study aimed to assess postural balance in LBP patients by analyzing intra-session reliability of CoP parameters on a portable force platform, the Romberg Ratio, and the OLST. Furthermore, we aimed to determine whether CoP parameters and OLST measure identical...

  14. 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)

  15. 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...

  16. 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...

  17. Procedure for Balancing an Air Distribution System with Decentralised Fans

    DEFF Research Database (Denmark)

    Gunner, Amalie; Hultmark, Göran; Vorre, Anders;

    2015-01-01

    of the fans. In conventional air distribution systems the fan provides the necessary pressure to overcome the resistance in the branch with the highest pressure resistance. This gives an unnecessary overpressure in the remaining branches that does not provide any useful purpose. In order to decrease the fan......This paper presents results from an on-going project concerning new design procedures for mechanical ventilation systems with low energy use. Conventional constant air volume (CAV) systems are usually balanced using flat plate dampers. The purpose of using balancing dampers is to intentionally...... introduce pressure drops in the duct system thus nominal airflows are achieved throughout the ductwork within specified tolerances. However, introduction of pressure drops will increase energy requirement for the ventilation system and in addition, balancing a duct system is a time consuming task and often...

  18. A New Carbonate Chemistry in the Earth's Lower Mantle

    Science.gov (United States)

    Boulard, E.; Gloter, A.; Corgne, A.; Antonangeli, D.; Auzende, A.; Perrillat, J.; Guyot, F. J.; Fiquet, G.

    2010-12-01

    The global geochemical carbon cycle involves exchange between the Earth’s mantle and the surface. Carbon (C) is recycled into the mantle via subduction and released to the atmosphere via volcanic outgassing. Carbonates are the main C-bearing minerals that are transported deep in the Earth’s mantle via subduction of the oceanic lithosphere [1]. The way C is recycled and its contribution to the lower mantle reservoir is however largely unknown [ e.g 2, 3]. In this respect, it is important to assess if carbonates can be preserved in the deep mantle, or if decarbonatation, melting or reduction play a role in the deep carbon cycle. To clarify the fate of carbonates in the deep mantle, we carried out high-pressure and high-temperature experiments up to 105 GPa and 2850 K. Natural Fe-Mg carbonates or oxide mixtures of (Mg,Fe)O + CO2 were loaded into laser heated diamond anvil cells. In situ characterizations were done by X-ray Diffraction (XRD) using synchrotron radiation at the high-pressure beamline ID27 of the European Synchrotron Radiation Facility. A focused ion beam technique was then used to prepare the recovered samples for electron energy loss spectroscopy in a dedicated scanning transmission electron microscope (EELS-STEM) and scanning transmission X-ray microscopy (STXM). In situ XRD clearly shows the transformation of the initial carbonate phase into a new Mg-Fe high pressure carbonate phase at lower mantle conditions. We also provide direct evidence for recombination of CO2 with (Mg,Fe)O to form this new carbonate structure. In addition, subsequent EELS-STEM and STXM spectroscopies carried out on recovered samples yields C K-edge and stoechiometry characteristic to this new carbonate structure. This new high pressure phase concentrates a large amount of Fe(III), as a result of redox reactions within the siderite-rich carbonate. The oxidation of iron is balanced by partial reduction of carbon into CO groups and/or diamond. These reactions may provide an

  19. The cryogenic balance design and balance calibration methods

    Science.gov (United States)

    Ewald, B.; Polanski, L.; Graewe, E.

    1992-07-01

    The current status of a program aimed at the development of a cryogenic balance for the European Transonic Wind Tunnel is reviewed. In particular, attention is given to the cryogenic balance design philosophy, mechanical balance design, reliability and accuracy, cryogenic balance calibration concept, and the concept of an automatic calibration machine. It is shown that the use of the automatic calibration machine will improve the accuracy of calibration while reducing the man power and time required for balance calibration.

  20. 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

  1. Aplikace Balanced Scorecard

    OpenAIRE

    Jaroměřská, Martina

    2015-01-01

    This master's thesis deals with application of the Balanced Scorecard method to Němcova selská mlékárna Radonice, spol. s.r.o. The goal is to analyse the strategic position of the company and propose a new company strategy. Further, the strategic goals defined by the strategy are converted to a strategic map to clearly show causality relationships between the goals of the four perspectives of the Balanced Scoreboard method. The strategic goals are assigned measures and target values and initi...

  2. 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.......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....

  3. 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...

  4. 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.

  5. A balanced team generating model

    NARCIS (Netherlands)

    van de Water, Tara; van de Water, Henny; Bukman, Cock

    2007-01-01

    This paper introduces a general team balancing model. It first summarizes existing balancing methods. It is shown that for these methods it is difficult to meet all the conditions posed by Belbin on balanced teams. This mainly is caused by the complexity of the balancing problem. A mathematical mode

  6. Balanced Flow Metering and Conditioning: Technology for Fluid Systems

    Science.gov (United States)

    Kelley, Anthony R.

    2006-01-01

    Revolutionary new technology that creates balanced conditions across the face of a multi-hole orifice plate has been developed, patented and exclusively licensed for commercialization. This balanced flow technology simultaneously measures mass flow rate, volumetric flow rate, and fluid density with little or no straight pipe run requirements. Initially, the balanced plate was a drop in replacement for a traditional orifice plate, but testing revealed substantially better performance as compared to the orifice plate such as, 10 times better accuracy, 2 times faster (shorter distance) pressure recovery, 15 times less acoustic noise energy generation, and 2.5 times less permanent pressure loss. During 2004 testing at MSFC, testing revealed several configurations of the balanced flow meter that match the accuracy of Venturi meters while having only slightly more permanent pressure loss. However, the balanced meter only requires a 0.25 inch plate and has no upstream or downstream straight pipe requirements. As a fluid conditioning device, the fluid usually reaches fully developed flow within 1 pipe diameter of the balanced conditioning plate. This paper will describe the basic balanced flow metering technology, provide performance details generated by testing to date and provide implementation details along with calculations required for differing degrees of flow metering accuracy.

  7. 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)

  8. Modelling evapotranspiration using the surface energy balance systems (sebs) and landsat tm data (rabat region, morocco)

    NARCIS (Netherlands)

    Kwast, J. van der; Jong, S.M. de

    2004-01-01

    Modelling and understanding the surface energy balance is important for assessing the re-distribution of moisture and heat in soil and atmosphere. The Surface Energy Balance System (SEBS) estimates turbulent heat fluxes using satellite earth observation data in the visible, near infrared, and therma

  9. 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.)

  10. Strategic Balanced Scorecard Simulation

    DEFF Research Database (Denmark)

    Nielsen, Steen; Nielsen, Erland Hejn

    2012-01-01

    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...

  11. 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...

  12. Frihed, anerkendelse og balance

    DEFF Research Database (Denmark)

    Anker, Thomas Boysen

    2008-01-01

    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...

  13. Ballet Balance Strategies

    DEFF Research Database (Denmark)

    Pedersen, Camilla; Erleben, Kenny; Sporring, Jon

    2006-01-01

    Animating physically realistic human characters is challenging, since human observers are highly tuned to recognize human cues such as emotion and gender from motion patterns. The main contribution of this paper is a new model firmly based on biomechanics, which is used to animate balance and basic...

  14. 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.)

  15. Lives in the Balance.

    Science.gov (United States)

    Our Children, 1997

    1997-01-01

    Changes in the workplace that would provide flexibility for working parents are slowly developing and receiving government, business, and societal attention. A sidebar, "Mother, Professional, Volunteer: One Woman's Balancing Act," presents an account of how one woman rearranged her professional life to enable her to do full-time parenting. (SM)

  16. Regulation of Energy Balance.

    Science.gov (United States)

    Bray, George A.

    1985-01-01

    Explains relationships between energy intake and expenditure focusing on the cellular, chemical and neural mechanisms involved in regulation of energy balance. Information is referenced specifically to conditions of obesity. (Physicians may earn continuing education credit by completing an appended test). (ML)

  17. 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.)

  18. Numerical Simulation on Piston Buffering Characteristics of Pressure-balanced Underwater Torpedo Launch System%液压平衡式水下鱼雷发射系统活塞缓冲特性数值仿真

    Institute of Scientific and Technical Information of China (English)

    张孝芳; 胡坤; 由文立

    2011-01-01

    For researching the shock vibration resulted from the water cylinder piston buffering of the underwater torpedo launch system, computational fluid dynamics ( CFD) simulation is conducted to study the piston buffering characteristics. One-dimensional and CFD methods are combined in the simulation.The thermodynamic models of air bottle and cylinder, and the kinetic model of piston and weapon are described by using ordinary differential equations ( ODE ) , and they are solved by using four-order RungeKutta method. The seawater flows in cylinder, launch chamber and launch tube are solved by using CFD method. The applied force and velocity of the torpedo are used as coupling variables to account for the interaction between fluid and solids. The simulation results show that, at the end of the launch process, the pressure surges in piston buffering mechanism will generate shocks to submarine structure. To reduce the shock vibration and noise of underwater torpedo launch, the buffering mechanism should be redesigned optimally.%为研究水下鱼雷发射系统水缸活塞缓冲阶段对系统造成的冲击振动影响,采用计算流体力学(CFD)仿真对其缓冲机构特性进行研究.仿真中采用一维仿真与CFD仿真相结合的方法.气瓶与气缸热力学模型、活塞及鱼雷动力学模型均用一维常微分方程(ODE)描述,采用四阶龙格库塔法求解;包括水缸、发射水舱和发射管的整个海水区域的流体流动采用CFD方法求解.一维模型和流体计算模型之间用活塞与鱼雷的受力和运动速度作为中间变量相联系,从而实现流体与固体之间的耦合.仿真结果表明,发射结束时缓冲座内海水瞬时压力过高会对潜艇结构造成较大冲击,为降低鱼雷发射冲击振动与噪声必须对活塞缓冲机构进行优化.

  19. 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.

  20. 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

  1. CMEs at Earth and Mars

    Science.gov (United States)

    Falkenberg, T. V.; Vennerstrom, S.; Taktakishvili, A.; Pulkkinen, A.; Brain, D. A.; Delory, G. T.; Mitchell, D.

    2010-12-01

    We perform a survey of the longitudinal extent and general nature of fast Coronal Mass Ejections (CMEs) identifiable at both Mars and Earth and use the ENLIL Magneto-Hydro-Dynamic model to replicate data for the CMEs at both planets. We have chosen 18 fast CMEs with initial velocities, according to the SOHO/LASCO catalogue, between 1200 and 2700 km/s in the period 2001-2003. CME arrival is identified at Earth by sharp increases in velocity, density and magnetic field strength in data compiled from the ACE,WIND and Geotail spacecraft, while CME arrival at Mars is identified by a large increase in magnetic field strength and by increases in the background countrate of the Electron Reflectometer (ER) instrument on Mars Global Surveyor (MGS). The ER backgrounds are used to determine the presence of Solar Energetic Particles related to fast CMEs. We run ENLIL using two different sets of input parameters, both estimated from SOHO/LASCO images, but one set is estimated manually and one set is estimated using an automated method. Specific parameters of interest are arrival time, longitudinal span, and propagation direction of the CMEs. At Earth the velocity, density and magnetic field strength are compared to Omni data, while at Mars the solar wind dynamic pressure is compared to an upstream pressure proxy estimated from magnetic field data from MGS. A qualitative estimate of the usefulness of ENLIL in CME modeling will be given, as well as a comparison of the effectiveness of the two methods used to find input parameters for the model.

  2. 负压脉冲可调式平衡吸乳器用于产后早期辅助开奶效果观察%Effects Observation of Negative Pressure Pulse Adjustable Balance Breast Pump using in Early Milk Opening after Postpartum

    Institute of Scientific and Technical Information of China (English)

    侯振平

    2014-01-01

    To investigate the clinical effects of negative pulse adjustable balance breast pump using in early milk opening after postpartum.Methods:250 cases with no breast-feeding contraindications were randomized,130 cases using negative pressure pulse adjustable balance breast pump maternal were distributed into observation group,and 120 cases given routine nursing care were distributed into control group.Results:The degree of breast pain was significantly reduced in observation group than control group (P<0.01),ductal patency time was significantly shorter in observation group (P<0.05),the success rate of breast feeding improved (P<0.05). Conclusion:Negative pulse adjustable balance breast pump using in early milk opening after postpartum can effectively reduce the dredging breast duct,breast pain,improve the success rate of breast feeding.%目的:探讨负压脉冲可调式平衡吸乳器用于产后早期辅助开奶的临床效果。方法:无母乳喂养禁忌证初产妇250例随机分组,使用负压脉冲可调式平衡吸乳器产妇130例为观察组,仅给予产后常规护理产妇120例为对照组。结果:观察组较对照组乳房胀痛程度明显减轻(P<0.01),乳腺管通畅时间缩短(P<0.05)、母乳喂养成功率提高(P<0.05)。结论:产后早期使用负压脉冲可调式平衡吸乳器辅助开奶,可及时有效疏通乳腺管,减少乳房胀痛的发生,有利于提高母乳喂养成功率。

  3. Near Earth Objects

    DEFF Research Database (Denmark)

    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 climate changes, yet the threat from a collision with a near Earth object has only recently been recognised...

  4. Energy balances 2001

    International Nuclear Information System (INIS)

    Denmark's consumption of energy increased 1,6 % from 2000 to 2001, primarily due to the year 2001 being colder than the year 2000. The production of petroleum decreased from 2000 to 2001, the reason being an accident at the Gorm oil field. The production of renewable energy and natural gas, however, increased. The energy balances is an account of production, import and export, and consumption of energy. The consumption is presented for households and industry. In the energy balances the energy consumption is accounted as physical amounts as well as gross consumption. Also an account is made of the costs of energy in basis prices and in market prices, including calculation of excises on energy, CO2 and SO2. (ln)

  5. Capturing near-Earth asteroids around Earth

    Science.gov (United States)

    Hasnain, Zaki; Lamb, Christopher A.; Ross, Shane D.

    2012-12-01

    The list of detected near-Earth asteroids (NEAs) is constantly growing. NEAs are likely targets for resources to support space industrialization, as they may be the least expensive source of certain needed raw materials. The limited supply of precious metals and semiconducting elements on Earth may be supplemented or even replaced by the reserves floating in the form of asteroids around the solar system. Precious metals make up a significant fraction NEAs by mass, and even one metallic asteroid of ˜1km size and fair enrichment in platinum-group metals would contain twice the tonnage of such metals already harvested on Earth. There are ˜1000 NEAs with a diameter of greater than 1 km. Capturing these asteroids around the Earth would expand the mining industry into an entirely new dimension. Having such resources within easy reach in Earth's orbit could provide an off-world environmentally friendly remedy for impending terrestrial shortages, especially given the need for raw materials in developing nations. In this paper, we develop and implement a conceptually simple algorithm to determine trajectory characteristics necessary to move NEAs into capture orbits around the Earth. Altered trajectories of asteroids are calculated using an ephemeris model. Only asteroids of eccentricity less than 0.1 have been studied and the model is restricted to the ecliptic plane for simplicity. We constrain the time of retrieval to be 10 years or less, based on considerations of the time to return on investment. For the heliocentric phase, constant acceleration is assumed. The acceleration required for transporting these asteroids from their undisturbed orbits to the sphere of influence of the Earth is the primary output, along with the impulse or acceleration necessary to effect capture to a bound orbit once the Earth's sphere of influence is reached. The initial guess for the constant acceleration is provided by a new estimation method, similar in spirit to Edelbaum's. Based on the

  6. Getting the Balance Right

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    In the next five years China will balance economic growth and improving the living standards of its people by Liu Wei IT was widely reported that the chaos in some Middle East and North African countries were results of the inadequate efforts in improving people’s livelihood, a fundamental aspect of social stability. In early March,China held its annual sessions of the National People’s

  7. Ballet Balance Strategies

    OpenAIRE

    Pedersen, Camilla; Erleben, Kenny; Sporring, Jon

    2006-01-01

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

  8. Thinking About Competitive Balance

    OpenAIRE

    Allen R. Sanderson; John J. Siegfried

    2003-01-01

    Simon Rottenberg long ago noted that the nature of sports is such that competitors must be of approximately equal ability if any are to be financially successful. In recent years, sports commentators and fans, Major League Baseball itself, and even some economists have expressed growing concern about the widening disparities among team expenditures and the growing concentrations of postseason contenders and championships. In this article we compare different concepts of competitive balance, r...

  9. 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

  10. Balancing innovation and evidence.

    Science.gov (United States)

    Pilcher, Jobeth W

    2015-01-01

    Nurse educators are encouraged to use evidence to guide their teaching strategies. However, evidence is not always available. How can educators make decisions regarding strategies when data are limited or absent? Where do innovation and creativity fit? How can innovation be balanced with evidence? This article provides a discussion regarding other sources of evidence, such as extrapolations, theories and principles, and collective expertise. Readers are encouraged to review the options and then analyze how they might be applied to innovation in education.

  11. 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.)

  12. Geochemistry of Rare Earth Elements in Aktishikan Gold Deposit, Xinjiang

    Institute of Scientific and Technical Information of China (English)

    袁峰; 周涛发; 岳书仓

    2002-01-01

    The characteristics and the models of rare earth elements in the geolo gical bodies and the hydrothermal water balanced with the adamellite were compre h ensively studied in Aktishikan gold deposit,Nurt area of Altay,Xinjiang.And th e behavior of rare earth elements during metasomatic alteration was discussed by using the isocon method of Grant.The results show that the rare earth elements a re inert during metasomatic alteration,the hydrothermal water has no relation t o the magmatic water,and the gold material sources mainly stem from the wall rock.

  13. 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.

  14. Gait and balance disorders.

    Science.gov (United States)

    Masdeu, Joseph C

    2016-01-01

    This chapter focuses on one of the most common types of neurologic disorders: altered walking. Walking impairment often reflects disease of the neurologic structures mediating gait, balance or, most often, both. These structures are distributed along the neuraxis. For this reason, this chapter is introduced by a brief description of the neurobiologic underpinning of walking, stressing information that is critical for imaging, namely, the anatomic representation of gait and balance mechanisms. This background is essential not only in order to direct the relevant imaging tools to the regions more likely to be affected but also to interpret correctly imaging findings that may not be related to the walking deficit object of clinical study. The chapter closes with a discussion on how to image some of the most frequent etiologies causing gait or balance impairment. However, it focuses on syndromes not already discussed in other chapters of this volume, such as Parkinson's disease and other movement disorders, already discussed in Chapter 48, or cerebellar ataxia, in Chapter 23, in the previous volume. As regards vascular disease, the spastic hemiplegia most characteristic of brain disease needs little discussion, while the less well-understood effects of microvascular disease are extensively reviewed here, together with the imaging approach. PMID:27430451

  15. 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

  16. 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.

  17. Modeling the surface temperature of Earth-like planets

    CERN Document Server

    Vladilo, G; Murante, G; Filippi, L; Provenzale, A

    2015-01-01

    We introduce a novel Earth-like planet surface temperature model (ESTM) for habitability studies based on the spatial-temporal distribution of planetary surface temperatures. The ESTM adopts a surface Energy Balance Model complemented by: radiative-convective atmospheric column calculations, a set of physically-based parameterizations of meridional transport, and descriptions of surface and cloud properties more refined than in standard EBMs. The parameterization is valid for rotating terrestrial planets with shallow atmospheres and moderate values of axis obliquity (epsilon >= 45^o). Comparison with a 3D model of atmospheric dynamics from the literature shows that the equator-to-pole temperature differences predicted by the two models agree within ~5K when the rotation rate, insolation, surface pressure and planet radius are varied in the intervals 0.5 <= Omega/Omega_o <= 2, 0.75 <= S/S_o <= 1.25, 0.3 <= p/(1 bar) <= 10, and 0.5 <= R/R_o <= 2, respectively. The ESTM has an extremely l...

  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. Lunar origin from impact on the Earth

    Science.gov (United States)

    Stevenson, D. J.

    1984-01-01

    All theories of lunar origin involve events or processes which seemingly have low efficiencies or low probabilities or both. An impact-triggered fission lunar origin is presented. If the impact ejecta (a mixture of target and projectile) leave the impact site ballistically and are subsequently acted upon only by the gravity field of a spherical Earth, then the ejecta either reimpacts the Earth or escapes on a hyperbolic trajectory. Hence the need for a second burn. Three possible resolutions are considered: pressure gradient acceleration, non-central gravity, and viscous spreading.

  20. Effects of insoles contact on static balance.

    Science.gov (United States)

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

    2016-04-01

    [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.

  1. Balanced skills among nascent entrepreneurs

    OpenAIRE

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

    2013-01-01

    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...

  2. Peer Pressure

    Science.gov (United States)

    ... How Can I Help a Friend Who Cuts? Peer Pressure KidsHealth > For Teens > Peer Pressure Print A A A Text Size What's in ... She'd just had a big dose of peer pressure. Who Are Your Peers? When you were a ...

  3. 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…

  4. 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…

  5. GRACE卫星太阳光照与地球反照辐射压力模型的效果分析%Analysis of Solar and Earth Albedo Radiation Pressure Models for GRACE on Their Performance

    Institute of Scientific and Technical Information of China (English)

    陈润静; 彭碧波; 高凡; 范城城

    2013-01-01

    应用GRACE产品说明书中的宏模参数,将模型计算结果与加速度计在径向与法向的非保守力实测值进行比较,结果显示两者之间具有较好的吻合性.通过改变卫星侧面的镜面反射以及漫反射系数,观察模型计算结果与实测数据之间的吻合度变化情况,发现宏模给出的反射系数可能较真实情况偏大.直接使用宏模参数并将其应用于动力学定轨试验,结果表明,本文采用的光照辐射压力模型满足动力学定轨的精度需要,且较传统Knocke地球反照辐射模型在效果上有了较大的改进.%Accurate model of radiation pressure is essential in determining the variations of the thermospheric density and the winds from accelerometer aboard the GRACE. In order to analyse the radiation model we employed in the paper, modeled radiation acceleration is compared with observed value from accelerometer in radial and cross-track components, which shows that they coincide with each other well. By changing the specular and diffusive reflectivity coefficients in Starboard panel, we observe the change in agreement between modeled acceleration and actual measurement, finding that the reflectivity coefficients in macro-model may be overestimated. By implementing the radiation pressure model inorbit determination with raw macro-model coefficients, the result indicates that the model meets the precision requirement of dynamical orbit determination, making considerable improvement in performance when compared with traditional Knocke model.

  6. 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.

  7. Relationships between fear of falling, balance confidence, and control of balance, gait, and reactive stepping in individuals with sub-acute stroke.

    Science.gov (United States)

    Schinkel-Ivy, Alison; Inness, Elizabeth L; Mansfield, Avril

    2016-01-01

    Fear of falling is common in individuals with stroke; however, the associations between fear of falling, balance confidence, and the control of balance and gait are not well understood for this population. This study aimed to determine whether, at the time of admission to in-patient rehabilitation, specific features of balance and gait differed between individuals with stroke who did and did not report fear of falling, and whether these features were related to balance confidence. Individuals with stroke entering in-patient rehabilitation were asked if they were afraid of falling, and completed the Activities-Specific Balance Confidence Scale. Participants performed quiet standing, gait, and reactive stepping tasks, and specific measures were extracted for each (quiet standing: centre of pressure amplitude, between-limb synchronization, and Romberg quotients; gait: walking velocity, double support time, and variability measures; reactive stepping: number of steps, frequency of grasp reactions, and frequency of assists). No significant differences were identified between individuals with and without fear of falling. Balance confidence was negatively related to centre of pressure amplitude, double support time, and step time variability, and positively related to walking velocity. Low balance confidence was related to poor quiet standing balance control and cautious behavior when walking in individuals with sub-acute stroke. While the causal relationship between balance confidence and the control of balance and gait is unclear from the current work, these findings suggest there may be a role for interventions to increase balance confidence among individuals with stroke, in order to improve functional mobility.

  8. 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

  9. Application of earth pressure monitoring in the analysis of settlement for composite foundation with rigid piles under high fill%土压力监测在高填方下刚性桩复合地基沉降分析中的应用

    Institute of Scientific and Technical Information of China (English)

    张辉; 刘国; 陈昌彦

    2011-01-01

    本文通过对京津二通道(五环路-天津)高速公路高填方路基下CFG桩基础的土压力观测数据进行分析,对比高填方路基下的沉降观测数据及理论计算的最终沉降量,对柔性基础下刚性桩复合地基承载力变化情况进行了研究.通过实例分析了柔性基础下刚性桩复合地基的桩土应力比变化情况,指出了影响桩顶、桩间土压力变化的影响因素,说明了因为土压力计感应膜的位置差异造成的桩间土土压力的"欠读"现象(即测读值偏小),并指出了通过改变垫层刚度来增加刚性桩复合地基的基础刚度这一调节桩土应力比的手段.%Through analyzing the field testing data of the earth pressure of the CFG pile foundation under the high fill subgrade for the second highway from Beijing to Tianjin (Fifth Ring Road to Tianjin boundary), the settlement data and the final theoretical calculation settlement data are contrasted, and the bearing capacity variation of the composite foundation with rigid piles under the flexible foundation are studied. Based on the example, the variation of the pile-soil stress ratio of the composite foundation is analyzed, and the factors to influence the pressure variations of the pile top and the soil between piles are pointed out. The“ less reading” phenomenon of earth pressure between piles which is caused by the location difference of the sensing membrane of the soil manometer is explained, and the means to regulate the pile-soil stress ratio which could increase the stiffness of the composite foundation through changing the cushion stiffness are presented.

  10. 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

  11. Balancing innovation and evidence.

    Science.gov (United States)

    Pilcher, Jobeth W

    2015-01-01

    Nurse educators are encouraged to use evidence to guide their teaching strategies. However, evidence is not always available. How can educators make decisions regarding strategies when data are limited or absent? Where do innovation and creativity fit? How can innovation be balanced with evidence? This article provides a discussion regarding other sources of evidence, such as extrapolations, theories and principles, and collective expertise. Readers are encouraged to review the options and then analyze how they might be applied to innovation in education. PMID:25790361

  12. Pressurized SOFC systems for stationary applications

    OpenAIRE

    Leucht, Florian; Seidler, Stephanie; Henke, Moritz; Bessler, Wolfgang G.; Kallo, Josef; Friedrich, K. Andreas

    2009-01-01

    Solid oxide fuel cell (SOFC) systems show very high electrical efficiencies even at small sizes. DLR applies a multidisciplinary and multiscale approach to designing and optimizing pressurized SOFC systems for hybrid power plants. A large Simulink model library was developed featuring balance-of-plant components as well as fuel cell models. Recently a pressurized cell test rig was taken into operation.

  13. Production Balance of Ship Erection

    Institute of Scientific and Technical Information of China (English)

    JIANG Ru-hong; TAN Jia-hua; LIU Cun-gen

    2008-01-01

    A network plan model of ship erection was established based on the network planning technologyand the work-package breakdown system. The load-oriented production control method was introduced to buildup a throughput diagram model thus it is possible to describe the ship erection process numerically. Based onthe digitaiized models some cases of production balance of ship erection were studied and three balance indexeswere put forward, they are the load balance rate, the input manpower balance rate and the maximum gantrycrane operating times. Such an analytic method based on the balance evaluation is the important foundationfor digitization and intelligentization of shipyard production management.

  14. 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

  15. Neural Networks Based Component Content Soft-Sensor in Countercurrent Rare-Earth Extraction

    Institute of Scientific and Technical Information of China (English)

    杨辉; 谭明皓; 柴天佑

    2003-01-01

    The equilibrium model for multicomponent rare earth extraction is developed using neural networks, which combined with the material balance model could give online prediction of component content in countercurrent rare earth extraction production. Simulation experiments with industrial operation data prove the effect iveness of the hybrid soft- sensor.

  16. Balance of multi-wavelets

    Institute of Scientific and Technical Information of China (English)

    MAO Yibo

    2003-01-01

    The discrete scalar data need prefiltering when transformed by discrete multi-wavelet, but prefiltering will make some properties of multi-wavelets lost. Balanced multi-wavelets can avoid prefiltering. The sufficient and necessary condition of p-order balance for multi-wavelets in time domain, the interrelation between balance order and approximation order and the sampling property of balanced multi-wavelets are investigated. The algorithms of 1-0rder and 2-0rder balancing for multi-wavelets are obtained. The two algorithms both preserve the orthogonal relation between multi-scaling function and multi-wavelets. More importantly, balancing operation doesn't increase the length of filters, which suggests that a relatively short balanced multiwavelet can be constructed from an existing unbalanced multi-wavelet as short as possible.

  17. 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

  18. 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

  19. Negative leave balances

    CERN Document Server

    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...

  20. Negative leave balances

    CERN Document Server

    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...

  1. Earth from Above

    Science.gov (United States)

    Parkinson, Claire L.

    Earth from Above provides an easy introduction to understanding and interpreting satellite images, using illustrative examples to instruct on the fantastically informative new global data sets. Beginning with two short chapters on visible satellite images and radiation, the book then covers six key Earth-atmosphere variables on such environmentally important topics as the Antarctic ozone hole, El Nino, deforestation, the missing carbon dilemma, and the effects of sea ice, snow cover, and volcanoes on atmospheric temperatures. A final chapter broadens the discussion to consider satellite Earth observations in general.

  2. Axions from the Earth

    International Nuclear Information System (INIS)

    The possibility of axion production in the Earth's interior due to natural radioactive decay is considered. Axions, or axion-like particles, could be created in nuclear disintegrations and deexitations of natural radionuclides present in the Earth's crust and mantle, as well as due to photon to axion conversion of the emitted gamma rays via the Primakoff effect. The estimated geo-axion production rates and fluxes on the Earth's surface are given along with the axion coupling to ordinary matter in the frame of the simple axion models as well as for axion-like particles with stronger couplings

  3. Stable isotope composition of Earth's large lakes

    Science.gov (United States)

    Jasechko, S.; Gibson, J. J.; YI, Y.; Birks, S. J.; Sharp, Z. D.

    2011-12-01

    Lakes cover about three percent of Earth's continental area. Large lakes can significantly influence lake shore and regional climates by increasing specific humidity during evaporation and by moderating air temperatures. Stable isotopes of oxygen and hydrogen can be used to quantify lake evaporation, providing a supplementary and often cost-advantageous alternative to conventional hydrologic approaches that require over lake monitoring. Further, stable isotopes in lake sediments are an established tool in paleolimnology; however, interpreting changes to a lake's past isotope composition requires a comprehensive understanding of contemporary controls. Here, δ18O and δ2H values of water in modern lakes exceeding roughly five hundred square kilometres are compiled (n > 35). Voluminous and seasonally mixed lakes - such as the North American Great Lakes - have the most homogenous stable isotope compositions, while perennially-stratified and shallow lakes show greater variability. A rudimentary stable isotope mass balance is used to assess evaporation fluxes from large lakes on Earth. The approach taken simultaneously constrains evaporation outputs for both oxygen and hydrogen stable isotopes by accounting for lake effects on the overlying atmosphere. Model development highlights important considerations such as isotopic stratification (Tanganyika), disequilibrium isotopic mass balances (Baikal), and non-steady hydrologic balances. Further, the isotope composition of Earth's continental surface water reservoir is calculated. This value - weighted to volume - is δ18O = -7.5±1.7 per mille relative to standard mean ocean water. The compiled data may be a useful tracer of continental evaporate in global atmospheric water cycle studies and could be coupled to climate models capable of incorporating oxygen-18 and deuterium tracers to improve or validate calculations of lake effects on regional water cycling.

  4. 原状饱和黏土静止土压力系数试验研究%EXPERIMENTAL STUDIES OF STATIC EARTH PRESSURE COEFFICIENT OF UNDISTURBED SATURATED CLAY

    Institute of Scientific and Technical Information of China (English)

    黄博; 胡俊清; 廖先斌; 黄雄

    2013-01-01

    A number of K0-consolidation tests are carried out on the undisturbed mud/silt clay and silty clay samples of Hong Kong-Zhuhai-Macao bridge by using advanced triaxial apparatus. The changes of static soil pressure coefficient K0 under different loading and unloading paths are studied;and the applicability of using common formula and recommended value of specifications to estimate the K0 are analyzed,as well as the prediction equation based on test results is given. The results show that:K0 of mud/silt clay at the bottom of the Hong Kong-Zhuhai-Macao bridge immersed tunnel is a basically constant value(0.47). K0 of silty clay is proportional to the preconsolidation pressure and K0 is between 0.30 and 0.45;both of the bounds are lower than the recommended values of specifications and manuals for similar soil. In addition to soil properties,the cementation of the undisturbed samples also could make the K0 reduce. K0 of the strong structural undisturbed soil would decrease to below the values of normally consolidated clay and then rebound and gradually stabilize during loading stages. We can use the empirical formula given by the predecessors to estimate the K0 of normally consolidated and over-consolidated undisturbed clays;and the internal friction angle should be the effective peak internal friction angle of normally consolidated soil.%利用先进三轴仪进行港珠澳大桥岛隧工程原状土K0固结试验,研究不同加、卸载路径下土体静止土压力系数K0变化,分析常用经验公式及规范推荐值所估计静止土压力系数的适用性,并给出基于本次试验结果的预测公式。结果表明:港珠澳沉管隧道底面处的黏土层 K0基本为一定值,为0.47;粉质黏土层 K0与其先期固结压力成正比,在0.30~0.45范围内,均低于规范和手册对同类土的推荐值;除土性自身的原因外,原状样的胶结作用也会使其K0降低。结构性较强的原状土,在

  5. Global ENA Imaging of Earth's Dynamic Magnetosphere

    Science.gov (United States)

    Brandt, Pontus

    2015-04-01

    The interaction between singly charged ions of Earth's magnetosphere and its neutral exosphere and upper atmosphere gives rise to Energetic Neutral Atoms (ENAs). This has enabled several missions to remotely image the global injection dynamics of the ring current and plasma sheet, the outflow of ions from Earth's polar regions, and the location of the sub-solar magnetopause. In this presentation we review ENA observations by the Astrid, IMAGE, TWINS and IBEX missions. We focus on results from the IMAGE/HENA Camera including observations of proton and oxygen ion injections in to the ring current and their impact on the force-balance and ionospheric coupling in the inner magnetosphere. We report also on the status of inversion techniques for retrieving the ion spatial and pitch-angle distributions from ENA images. The presentation concludes with a discussion of future next steps in ENA instrumentation and analysis capabilities required to deliver the science as recommended by the Heliophysics Decadal Survey.

  6. 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.

  7. 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...

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

    Science.gov (United States)

    Cahalan, Robert F.

    2004-01-01

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

  9. 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

  10. 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).

  11. 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.

  12. Observing earth from Skylab

    Science.gov (United States)

    1975-01-01

    Skylab technology and observations of earth resources are discussed. Special attention was given to application of Skylab data to mapmaking, geology/geodesy, water resources, oceanography, meteorology, and geography/ecology.

  13. Earth science: Extraordinary world

    Science.gov (United States)

    Day, James M. D.

    2016-09-01

    The isotopic compositions of objects that formed early in the evolution of the Solar System have been found to be similar to Earth's composition -- overturning notions of our planet's chemical distinctiveness. See Letters p.394 & p.399

  14. 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)

  15. Extremophiles: Link between earth and astrobiology

    OpenAIRE

    Stojanović Dejan B.; Fojkar Oliver; Drobac-Čik Aleksandra V.; Čajko Kristina O.; Dulić Tamara I.; Svirčev Zorica B.

    2008-01-01

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

  16. Mathematics of Planet Earth

    Directory of Open Access Journals (Sweden)

    Željka Tutek

    2013-12-01

    Full Text Available 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.

  17. Afganistan and rare earths

    OpenAIRE

    Emilian M. Dobrescu; Edith Mihaela Dobre

    2013-01-01

    On our planet, over a quarter of new technologies for the economic production of industrial goods, are using rare earths, which are also called critical minerals and industries that rely on these precious items being worth of an estimated nearly five trillion dollars, or 5 percent of world gross domestic product. In the near future, competition will increase for the control of rare earth minerals embedded in high-tech products. Rare minerals are in the twenty-first century what oil accounted ...

  18. 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.

  19. 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.

  20. 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.

  1. A Balancing Act?

    DEFF Research Database (Denmark)

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

    the 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...

  2. Balancing Trust and Control

    DEFF Research Database (Denmark)

    Jagd, Søren

    2010-01-01

    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 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 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...

  3. Toward other Earths

    Science.gov (United States)

    Hatzes, Artie P.

    2016-04-01

    How common are habitable Earth-like planets? This is a key question that drives much of current research in exoplanets. To date, we have discovered over one thousand exoplanets, mostly through the transit method. Among these are Earth-size planets, but these orbit very close to the star (semi-major axis approximately 0.01 Astronomical Units). Potentially rocky planets have also been discovered in a star's habitable zone, but these have approximately twice the radius of the Earth. These certainly do not qualify as Earth "twins". Several hundreds of multi-planet systems have also been discovered, but these are mostly ultra-compact systems with up to seven planets all with orbital distances less than that of Mercury in our solar system. The detection of a planetary system that is the direct analog of our solar system still eludes us. After an overview of the current status of exoplanet discoveries I will discuss the prospects and challenges of finding such Earth analogs from the ground and from future space missions like PLATO. After over two decades of searching, we may well be on the brink of finding other Earths.

  4. 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.

  5. A volume-balance model for flow on porous media

    Science.gov (United States)

    Malaga, Carlos; Mandujano, Francisco; Becerra, Julian

    2015-11-01

    Volume-balance models are used by petroleum engineers for simulating multiphase and multicomponent flow phenomena in porous media and the extraction process in oil reservoirs. In these models, mass conservation equations and Darcy's law are supplemented by a balance condition for the pore and fluid volumes. This provides a pressure equation suitable for simulating a compressible flow within a compressible solid matrix. Here we present an alternative interpretation of the volume-balance condition that includes the advective transport within a consolidated porous media. We obtain a modified equation for the time evolution of the pressure field. Numerical tests for phase separation under gravity are presented for multiphase three dimensional flow in heterogeneous porous media. The authors acknowledge funding from Fondo Sectorial CONACYT-SENER grant number 42536 (DGAJ-SPI-34-170412-217).

  6. Balancing on a narrow ridge : biomechanics and control

    NARCIS (Netherlands)

    Otten, Ellen

    1999-01-01

    The balance of standing humans is usually explained by the inverted pendulum model. The subject invokes a horizontal ground-reaction force in this model and controls it by changing the location of the centre of pressure under the foot or feet. In experiments I showed that humans are able to stand on

  7. The Solubility of Rock in Steam Atmospheres of the Early Earth and Hot Rocky Exoplanets

    Science.gov (United States)

    Fegley, Bruce

    2016-07-01

    Extensive experimental studies show all major rock-forming elements (e.g., Si, Mg, Fe, Ca, Al, Na, K) dissolve in steam to a greater or lesser extent. We use these results to compute chemical equilibrium abundances of rocky element - bearing gases in steam atmospheres equilibrated with silicate magma oceans. Rocky elements partition into steam atmospheres as volatile hydroxide gases (e.g., Si(OH)4, Mg(OH)2, Fe(OH)2, Ni(OH)2, Al(OH)3, Ca(OH)2, NaOH, KOH) and via reaction with HF and HCl as volatile halide gases (e.g., NaCl, KCl, CaFOH, CaClOH, FAl(OH)2) in much larger amounts than expected from their vapor pressures over volatile-free solid or molten rock at high temperatures expected for steam atmospheres on the early Earth and hot rocky exoplanets. We quantitatively compute the extent of fractional vaporization by defining gas/magma distribution coefficients and show Earth's sub-solar Si/Mg ratio may be due to loss of a primordial steam atmosphere. We conclude hot rocky exoplanets that are undergoing or have undergone escape of steam-bearing atmospheres may experience fractional vaporization and loss of Si, Mg, Fe, Ni, Al, Ca, Na, and K. This loss can modify their bulk composition, density, heat balance, and interior structure. This work was supported by NSF Astronomy Program Grant AST-1412175.

  8. 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.

  9. Variance approximation under balanced sampling

    OpenAIRE

    Deville, Jean-Claude; Tillé, Yves

    2016-01-01

    A balanced sampling design has the interesting property that Horvitz–Thompson estimators of totals for a set of balancing variables are equal to the totals we want to estimate, therefore the variance of Horvitz–Thompson estimators of variables of interest are reduced in function of their correlations with the balancing variables. Since it is hard to derive an analytic expression for the joint inclusion probabilities, we derive a general approximation of variance based on a residual technique....

  10. Radar channel balancing with commutation

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter

    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.

  11. Approaching a realistic force balance in geodynamo simulations

    CERN Document Server

    Yadav, Rakesh K; Christensen, Ulrich R; Wolk, Scott J; Poppenhaeger, Katja

    2016-01-01

    Earth sustains its magnetic field by a dynamo process driven by convection in the liquid outer core. Geodynamo simulations have been successful in reproducing many observed properties of the geomagnetic field. However, while theoretical considerations suggest that flow in the core is governed by a balance between Lorentz force, rotational force and buoyancy (called MAC balance for Magnetic, Archimedean, Coriolis) with only minute roles for viscous and inertial forces, dynamo simulations must employ viscosity values that are many orders of magnitude larger than in the core due to computational constraints. In typical geodynamo models viscous and inertial forces are not much smaller than the Coriolis force and the Lorentz force plays a sub-dominant role. This has led to conclusions that these simulations are viscously controlled and do not represent the physics of the geodynamo. Here we show by a direct analysis of the relevant forces that a MAC balance can be achieved when the viscosity is reduced to values cl...

  12. 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 structural realist prediction that the weaker states should balance the unipole. Under a slight model extension, it is shown that efforts to balance in separate capabilities always tends to offset each other. Under this extension, the durability of the unipolar moment is in fact consistent...

  13. What is a balanced program?

    Science.gov (United States)

    Mohl, P C

    1995-06-01

    "Balance" has become the watchword of psychiatry programs. It seems that almost all residency training programs claim to be balanced. But what do we mean by this term? This article summarizes the author's evolving thinking about what makes for a balanced program and suggests that diversity may be a better term. The author advocates that balance is not as simple as teaching both psychodynamics and biological psychiatry. Instead, it entails a considered, intellectual approach that involves long-term vs. other psychotherapies, neuro-science vs. psychopharmacology, theoretical pharmacology vs. practical pharmacology, social psychiatry vs. treating minority patients, representing all viewpoints in psychiatry vs. integrating them. PMID:24442525

  14. 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.

  15. 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

  16. A new program in earth system science education

    Science.gov (United States)

    Huntress, Wesley; Kalb, Michael W.; Johnson, Donald R.

    1990-01-01

    A program aimed at accelerating the development of earth system science curricula at the undergraduate level and at seeding the establishment of university-based mechanisms for cooperative research and education among universities and NASA has been initiated by the Universities Space Research Association (USRA) in conjunction with NASA. Proposals were submitted by 100 U.S. research universities which were selected as candidates to participate in a three-year pilot program to develop undergraduate curricula in earth system science. Universities were then selected based upon peer review and considerations of overall scientific balance among proposed programs. The program will also aim to integrate a number of universities with evolving earth system programs, linking them with a cooperative curriculum, shared faculty, and NASA scientists in order to establish a stronger base for earth systems related education and interdisciplinary research collaboration.

  17. 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.

  18. 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.

  19. 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

  20. 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 ...

  1. 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.

  2. Adaptive Load Balancing of Parallel Applications with Multi-Agent Reinforcement Learning on Heterogeneous Systems

    OpenAIRE

    Johan Parent; Katja Verbeeck; Jan Lemeire; Ann Nowe; Kris Steenhaut; Erik Dirkx

    2004-01-01

    We report on the improvements that can be achieved by applying machine learning techniques, in particular reinforcement learning, for the dynamic load balancing of parallel applications. The applications being considered in this paper are coarse grain data intensive applications. Such applications put high pressure on the interconnect of the hardware. Synchronization and load balancing in complex, heterogeneous networks need fast, flexible, adaptive load balancing algorithms. Viewing a parall...

  3. 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

  4. 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...

  5. Balancing safety and economics

    International Nuclear Information System (INIS)

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

  6. 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...

  7. 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

  8. A balanced memory network.

    Directory of Open Access Journals (Sweden)

    Yasser Roudi

    2007-09-01

    Full Text Available A fundamental problem in neuroscience is understanding how working memory--the ability to store information at intermediate timescales, like tens of seconds--is implemented in realistic neuronal networks. The most likely candidate mechanism is the attractor network, and a great deal of effort has gone toward investigating it theoretically. Yet, despite almost a quarter century of intense work, attractor networks are not fully understood. In particular, there are still two unanswered questions. First, how is it that attractor networks exhibit irregular firing, as is observed experimentally during working memory tasks? And second, how many memories can be stored under biologically realistic conditions? Here we answer both questions by studying an attractor neural network in which inhibition and excitation balance each other. Using mean-field analysis, we derive a three-variable description of attractor networks. From this description it follows that irregular firing can exist only if the number of neurons involved in a memory is large. The same mean-field analysis also shows that the number of memories that can be stored in a network scales with the number of excitatory connections, a result that has been suggested for simple models but never shown for realistic ones. Both of these predictions are verified using simulations with large networks of spiking neurons.

  9. Electronic structure and properties of rare earth and actinide intermetallics

    International Nuclear Information System (INIS)

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

  10. Dagik Earth and IUGONET

    Science.gov (United States)

    Ebisawa, K.; Koyama, Y.; Saito, A.; Sakamoto, S.; Ishii, M.; Kumano, Y.; Hazumi, Y.

    2015-09-01

    In this paper we introduce two independent projects in progress in Japan. Dagik Earth is a visualization project of the Earth and planets on a spherical screen using only a standard PC and a projector. Surface images of the Earth or planets (or whatever having spherical shape) in the equirectangular (plate carre) projection are projected on a spherical screen in the orthographic projection. As a result, the spherical screen becomes a virtual digital globe, which can be rotated using mouse or remote controller. Inter-university Upper atmosphere Global Observation NETwork (IUGONET) is a collaboration of five Japanese institutes to build a comprehensive database system for the metadata of the upper-atmospheric data taken by these institutes. We explain the IUGONET metadata database and iUgonet Data Analysis Software (UDAS) for upper atmospheric research.

  11. Better Than Earth

    Science.gov (United States)

    Heller, René

    2015-01-01

    Do we inhabit the best of all possible worlds? German mathematician Gottfried Leibniz thought so, writing in 1710 that our planet, warts and all, must be the most optimal one imaginable. Leibniz's idea was roundly scorned as unscientific wishful thinking, most notably by French author Voltaire in his magnum opus, Candide. Yet Leibniz might find sympathy from at least one group of scientists - the astronomers who have for decades treated Earth as a golden standard as they search for worlds beyond our own solar system. Because earthlings still know of just one living world - our own - it makes some sense to use Earth as a template in the search for life elsewhere, such as in the most Earth-like regions of Mars or Jupiter's watery moon Europa. Now, however, discoveries of potentially habitable planets orbiting stars other than our sun - exoplanets, that is - are challenging that geocentric approach.

  12. Better Than Earth

    CERN Document Server

    Heller, René

    2015-01-01

    Do We Inhabit The Best O All Possible Worlds? German mathematician Gottfried Leibniz thought so, writing in 1710 that our planet, warts and all, must be the most optimal one imaginable. Leibniz's idea was roundly scorned as unscientific wishful thinking, most notably by French author Voltaire in his magnum opus, Candide. Yet Leibniz might find sympathy from at least one group of scientists - the astronomers who have for decades treated Earth as a golden standard as they search for worlds beyond our own solar system. Because earthlings still know of just one living world - our own - it makes some sense to use Earth as a template in the search for life elsewhere, such as in the most Earth-like regions of Mars or Jupiter's watery moon Europa. Now, however, discoveries of potentially habitable planets orbiting stars other than our sun - exoplanets, that is - are challenging that geocentric approach.

  13. Optimal allocation in balanced sampling

    OpenAIRE

    Tillé, Yves; Favre, Anne-Catherine

    2016-01-01

    The development of new sampling methods allows the selection of large balanced samples. In this paper we propose a method for computing optimal inclusion probabilities for balanced samples. Next, we show that the optimal Neyman allocation is a particular case of this method.

  14. H∞ Balancing for Nonlinear Systems

    NARCIS (Netherlands)

    Scherpen, Jacquelien M.A.

    1996-01-01

    In previously obtained balancing methods for nonlinear systems a past and a future energy function are used to bring the nonlinear system in balanced form. By considering a different pair of past and future energy functions that are related to the H∞ control problem for nonlinear systems we define H

  15. Nutrient balance at chain level

    NARCIS (Netherlands)

    Mu, W.; Middelaar, van C.E.; Bloemhof, J.M.; Oenema, J.; Boer, de I.J.M.

    2016-01-01

    A nutrient balance approach is often used to quantify losses of nutrients, such as nitrogen and phosphorus, that contribute to environmental problems such as eutrophication. A nutrient balance generally is computed at farm level, implying that nutrient losses related to pre-farm processes, such a

  16. Risk, Balanced Skills and Entrepreneurship

    NARCIS (Netherlands)

    C. Hsieh; S.C. Parker; M.C. van Praag

    2015-01-01

    This paper proposes that risk aversion encourages individuals to invest in balanced skill profiles, making them more likely to become entrepreneurs. By not having taken this possible linkage into account, previous research has underestimated the impacts both of risk aversion and balanced skills on t

  17. Designing Multinational Electricity Balancing Markets

    NARCIS (Netherlands)

    Van der Veen, R.A.C.

    2012-01-01

    In today’s unbundled electricity markets, the balancing market is an intricate institutional arrangement that makes sure that the balance between electricity supply and demand is maintained. In the light of the development of a single electricity market in Europe, harmonization and integration of cu

  18. Geoneutrino and Hydridic Earth model

    CERN Document Server

    Bezrukov, Leonid

    2013-01-01

    Uranium, Thorium and Potassium-40 abundances in the Earth were calculated in the frame of Hydridic Earth model. Terrestrial heat producton from U, Th and K40 decays was calculated also. We must admit the existance of Earth expansion process to understand the obtained large value of terrestrial heat producton. The geoneutrino detector with volume more than 5 kT (LENA type) must be constructed to definitely separate between Bulk Silicat Earth model and Hydridic Earth model.

  19. How Big is Earth?

    Science.gov (United States)

    Thurber, Bonnie B.

    2015-08-01

    How Big is Earth celebrates the Year of Light. Using only the sunlight striking the Earth and a wooden dowel, students meet each other and then measure the circumference of the earth. Eratosthenes did it over 2,000 years ago. In Cosmos, Carl Sagan shared the process by which Eratosthenes measured the angle of the shadow cast at local noon when sunlight strikes a stick positioned perpendicular to the ground. By comparing his measurement to another made a distance away, Eratosthenes was able to calculate the circumference of the earth. How Big is Earth provides an online learning environment where students do science the same way Eratosthenes did. A notable project in which this was done was The Eratosthenes Project, conducted in 2005 as part of the World Year of Physics; in fact, we will be drawing on the teacher's guide developed by that project.How Big Is Earth? expands on the Eratosthenes project by providing an online learning environment provided by the iCollaboratory, www.icollaboratory.org, where teachers and students from Sweden, China, Nepal, Russia, Morocco, and the United States collaborate, share data, and reflect on their learning of science and astronomy. They are sharing their information and discussing their ideas/brainstorming the solutions in a discussion forum. There is an ongoing database of student measurements and another database to collect data on both teacher and student learning from surveys, discussions, and self-reflection done online.We will share our research about the kinds of learning that takes place only in global collaborations.The entrance address for the iCollaboratory is http://www.icollaboratory.org.

  20. Google Earth Engine

    Science.gov (United States)

    Gorelick, Noel

    2013-04-01

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

  1. Pressure sensor

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. Teaching earth science

    Science.gov (United States)

    Alpha, Tau Rho; Diggles, M.F.

    1998-01-01

    This CD-ROM contains 17 teaching tools: 16 interactive HyperCard 'stacks' and a printable model. They are separated into the following categories: Geologic Processes, Earthquakes and Faulting, and Map Projections and Globes. A 'navigation' stack, Earth Science, is provided as a 'launching' place from which to access all of the other stacks. You can also open the HyperCard Stacks folder and launch any of the 16 stacks yourself. In addition, a 17th tool, Earth and Tectonic Globes, is provided as a printable document. Each of the tools can be copied onto a 1.4-MB floppy disk and distributed freely.

  3. Rare (Earth Elements [score

    Directory of Open Access Journals (Sweden)

    Camilo Méndez

    2014-12-01

    Full Text Available Rare (Earth Elements is a cycle of works for solo piano. The cycle was inspired by James Dillon’s Book of Elements (Vol. I-V. The complete cycle will consist of 14 pieces; one for each selected rare (earth element. The chosen elements are Neodymium, Erbium, Tellurium, Hafnium, Tantalum, Technetium, Indium, Dysprosium, Lanthanium, Cerium, Europium, Terbium, Yttrium and Darmstadtium. These elements were selected due to their special atomic properties that in many cases make them extremely valuable for the development of new technologies, and also because of their scarcity. To date, only 4 works have been completed Yttrium, Technetium, Indium and Tellurium.

  4. Quantizing Earth surface deformations

    Directory of Open Access Journals (Sweden)

    C. O. Bowin

    2015-03-01

    Full Text Available The global analysis of Bowin (2010 used the global 14 absolute Euler pole set (62 Myr history from Gripp and Gordon (1990 and demonstrated that plate tectonics conserves angular momentum. We herein extend that analysis using the more detailed Bird (2003 52 present-day Euler pole set (relative to a fixed Pacific plate for the Earth's surface, after conversion to absolute Euler poles. Additionally, new analytical results now provide new details on upper mantle mass anomalies in the outer 200 km of the Earth, as well as an initial quantizing of surface deformations.

  5. 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

  6. High-pressure phases of alumina

    Science.gov (United States)

    Lyle, Matthew; Pickard, Chris; Needs, Richard

    2014-03-01

    Alumina (Al2O3) has been widely used as a pressure standard in static diamond anvil cell experiments and is a major chemical component of the Earth. So a detailed knowledge of its high-pressure stability is of great importance in both materials science and deep Earth science. A phase transition is known to occur at roughly 80-100 GPa between corundum and the Rh2O3 (II) structure. A second phase transition to the CaIrO3 structure occurs at even higher pressures. Here we present a computational structure search to reveal three additional structures which are competitive at these pressures but hitherto unknown to be stable in high-pressure alumina.

  7. Earth science framework research based on the digital earth platform

    Science.gov (United States)

    Liu, Rui; Kong, Xiangsheng; Miao, Fang; Ye, Chengming

    2007-06-01

    This paper explains the basic points of earth science research, reviews the notion of digital earth and suggests the basic concept of digital earth platform. Taking the theory of digital earth as an essence point and the framework of digital earth platform as a main clue, we mainly discuss: the basic theories of digital earth platform, a comparatively flawless model of earth science research framework based on the digital earth platform. The discussing issues involves the unified coordinate projecting, data updating, data transferring, data processing and analyzing and data displaying and a series of researches relating to energy sources, eco-system and disasters monitoring and forecasting with a combination of the suggested model of earth science research framework.

  8. Atmosphere-earth angular momentum exchange and ENSO cycle

    Institute of Scientific and Technical Information of China (English)

    钱维宏; 丑纪范

    1996-01-01

    The time series of the earth’s rotation rate, eastern equatorial Pacific sea surface temperature (Tss), sea level pressure (Psl) and atmospheric angular momentum (Maa) during 1976 -1989 are used to study the relation between atmosphere-earth angular momentum exchange and ENSO cycle. The result shows that (i) there are synergetic relationships among the variations of solid earth’s rotation, eastern equatorial Pacific T,, Psl, different latitude zonal Maa and global Maa; (ii) local atmosphere-ocean interaction over low-latitude area can form ENSO-like cycle through Hadley circulation; (iii) the solid earth and global atmosphere-ocean interaction can form some aperiodic behavior and asynchronous oscillations by mountain torque and earth spin anomalous friction torque acting on each component of solid earth-ocean-atmosphere system; and (iv) actual ENSO cycle is a phenomenon reflecting in Pacific basin through interaction among solid earth, global ocean and the atmosphere.

  9. Pressure losses in pneumatic transport

    OpenAIRE

    Ottjes, J.A.

    1982-01-01

    A model is derived to calculate the pressure losses originating from the dilute phase pneumatic transport of coarse particles in the horizontal stationary flow regime. The model is based on the balance of drag forces and frictional forces acting on the particles during pneumatic transport. The particles are characterized by the particle terminal velocity, the particle âwall sliding friction coefficient and the coefficient of restitution between particles and wall. The influence of the inhomog...

  10. Natural Transfer of Viable Microbes in Space. 1. From Mars to Earth and Earth to Mars

    Science.gov (United States)

    Mileikowsky, Curt; Cucinotta, Francis A.; Wilson, John W.; Gladman, Brett; Horneck, Gerda; Lindegren, Lennart; Melosh, Jay; Rickman, Hans; Valtonen, Mauri; Zheng, J. Q.

    2000-06-01

    The possibility and probability of natural transfer of viable microbes from Mars to Earth and Earth to Mars traveling in meteoroids during the first 0.5 Ga and the following 4 Ga are investigated, including: —radiation protection against the galactic cosmic ray nuclei and the solar rays; dose rates as a function of the meteorite's radial column mass (radius×density), combined with dose rates generated by natural radioactivity within the meteorite; and survival curves for some bacterial species using NASA's HZETRN transport code —other factors affecting microbe survival: vacuum; central meteorite temperatures at launch, orbiting, and arrival; pressure and acceleration at launch; spontaneous DNA decay; metal ion migration —mean sizes and numbers of unshocked meteorites ejected and percentage falling on Earth, using current semiempirical results —viable flight times for the microbe species Bacillus subtilis and Deinococcus radiodurans R1 —the approximate fraction of microbes (with properties like the two species studied) viably arriving on Earth out of those ejected from Mars during the period 4 Ga BP to the present time, and during the 700 Ma from 4.5 to 3.8 Ga. Similarly, from Earth to Mars. The conclusion is that if microbes existed or exist on Mars, viable transfer to Earth is not only possible but also highly probable, due to microbes' impressive resistance to the dangers of space transfer and to the dense traffic of billions of martian meteorites which have fallen on Earth since the dawn of our planetary system. Earth-to-Mars transfer is also possible but at a much lower frequency.

  11. Seismic rehabilitation and analysis of Chaohe earth dam

    Institute of Scientific and Technical Information of China (English)

    Lei Fu; Xiangwu Zeng

    2005-01-01

    Stability of earth dams during earthquakes has been a major concern for geotechnical engineers in seismic active regions. Liquefaction induced slope failure occurred at the upstream slope of a major earth dam in the suburb of Beijing, China, during the 1976 Tangshan Earthquake. The gravelly soil with loose initial condition liquefied under relatively small ground vibration. In recent years, a major seismic rehabilitation project was carried out on a similar earth dam nearby using dumped quarry stone. Seismic stability analysis was carried out using model test, finite element simulation, and pseudostatic slope stability program after taking into account the influence of excess pore pressure.

  12. Field Measurements and Pullout Tests of Reinforced Earth Retaining Wall

    Institute of Scientific and Technical Information of China (English)

    陈群; 何昌荣; 朱分清

    2004-01-01

    In this paper, field measurements and pullout tests of a new type of reinforced earth retaining wall, which is reinforced by trapezoid concrete blocks connected by steel bar, are described. Field measurements included settlements of the earth fill, tensile forces in the ties and earth pressures on the facing panels during the construction and at completion. Based on the measurements, the following statements can be made: ( 1 ) the tensile forces in the ties increased with the height of backfill above the tie and there is a tensile force crest in most ties; (2) at completion, the measured earth pressures along the wall face were between the values of the active earth pressures and the pressures at rest; (3) larger settlements occurred near the face of the wall where a zone of drainage sand and gravel was not compacted properly and smaller settlements occurred in the well-compacted backfill. The results of field pullout tests indicated that the magnitudes of pullout resistances as well as tensile forces induced in the ties were strongly influenced by the relative displacements between the ties and the backfill, and pullout resistances increased with the height of backfill above the ties and the length of ties.

  13. Social Balance Theory: Revisiting Heider’s Balance Theory for many agents

    OpenAIRE

    Hokky Situngkir; Deni Khanafiah

    2004-01-01

    We construct a model based on Heider’s social balance theory 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. Seve...

  14. New ESA Earth Explorer Missions

    Science.gov (United States)

    Herland, E.

    2006-12-01

    concentrating on the UTLS region. Linking with MetOP/NPOESS data will also useful insights into processes occurring in the lower troposphere. Carries an infrared and a microwave radiometer. FLEX Fluorescence Explorer Mission: Global remote sensing of vegetation photosynthesis through measurement of fluorescence. Photosynthesis by land vegetation is an important component of the global carbon cycle, and is closely linked to the hydrological cycle through transpiration. Will measure high spectral resolution reflectance and temperature, and provide a multi-angular capability. A-SCOPE Advanced Space Carbon and Climate Observation of Planet Earth: Total column CO2 with a nadir-looking pulsed CO2 differential Absorption Lidar (DIAL) for better understanding of the global carbon cycle and regional CO2 fluxes, as well as for validation of greenhouse-gases emission inventories. CoReH2O Cold Regions Hydrology High-resolution Observatory: Spatially detailed observations of key snow, ice, and water cycle characteristics necessary for understanding land surface, atmosphere and ocean processes and interactions by using two synthetic aperture radars at 9.6 and 17.2 GHz. Aims at closing the gaps in detailed information on snow glaciers and surface water, with improving modelling and prediction of water balance and streamflow for snow covered and glacierised basins, understanding and modelling the water and energy cycles in high latitudes, assessing and forecasting water supply from snow cover and glaciers, including the assessment of effects of climate change and monitoring land surface water extent in high latitudes and its relation to climate variability.

  15. Experimental Probing on Formation Mechanism of Hydrocarbon in Deep Earth

    Institute of Scientific and Technical Information of China (English)

    Weng Kenan; Xiao Wansheng; Zhang Huizi; Wang Benshan

    1997-01-01

    @@ In order to study the formation mechanism of hydrocarbon in the earth's interior, preliminary experiments on chemical reactions of wax, graphite, siderite with supercritical water have been carried out respectively under the conditions of temperature about 800~1500℃ and pressure approximately above 1 GPa. These reactions can produce a large amount of methane, together with some CO2 and a little other hydrocarbons, indicating that the reactions of carbon-bearing materials with supercritical water is possibly a new formation mechanism of hydrocarbon under the conditions of high temperature and high pressure in deep earth.

  16. Earth as art 4

    Science.gov (United States)

    ,

    2016-03-29

    Landsat 8 is the latest addition to the long-running series of Earth-observing satellites in the Landsat program that began in 1972. The images featured in this fourth installment of the Earth As Art collection were all acquired by Landsat 8. They show our planet’s diverse landscapes with remarkable clarity.Landsat satellites see the Earth as no human can. Not only do they acquire images from the vantage point of space, but their sensors record infrared as well as visible wavelengths of light. The resulting images often reveal “hidden” details of the Earth’s land surface, making them invaluable for scientific research.As with previous Earth As Art exhibits, these Landsat images were selected solely for their aesthetic appeal. Many of the images have been manipulated to enhance color variations or details. They are not intended for scientific interpretation—only for your viewing pleasure. What do you see in these unique glimpses of the Earth’s continents, islands, and coastlines?

  17. Magnetic rare earth superlattices

    DEFF Research Database (Denmark)

    Majkrzak, C.F.; Kwo, J.; Hong, M.;

    1991-01-01

    Advances in molecular beam epitaxy deposition techniques have recently made it possible to grow, an atomic plane at a time, single crystalline superlattices composed of alternating layers of a magnetic rare earth, such as Gd, Dy, Ho, or Er, and metallic Y, which has an identical chemical structure...

  18. Google Earth Science

    Science.gov (United States)

    Baird, William H.; Padgett, Clifford W.; Secrest, Jeffery A.

    2015-01-01

    Google Earth has made a wealth of aerial imagery available online at no cost to users. We examine some of the potential uses of that data in illustrating basic physics and astronomy, such as finding the local magnetic declination, using landmarks such as the Washington Monument and Luxor Obelisk as gnomons, and showing how airport runways get…

  19. Protect the Earth

    Institute of Scientific and Technical Information of China (English)

    张永兴

    2011-01-01

    The earth, a blue globe, is very beautiful. It is the home to all the living things. But the environment around us is becoming worse and worse. People cut down trees to build houses and throw about litter. The air pollution is almost everywhere in the world!

  20. Understanding Earth's Albedo Effect

    Science.gov (United States)

    Fidler, Chuck

    2012-01-01

    Earth and space science in the middle school classroom are composed of intricately intertwined sets of conceptual systems (AAAS 1993; NRC 1996). Some systems of study, such as the water and rock cycles, are quite explicit and often found as stand-alone middle school science units. Other phenomena are not so apparent, yet they play an extremely…

  1. Modeling Earth's Climate

    Science.gov (United States)

    Pallant, Amy; Lee, Hee-Sun; Pryputniewicz, Sara

    2012-01-01

    Systems thinking suggests that one can best understand a complex system by studying the interrelationships of its component parts rather than looking at the individual parts in isolation. With ongoing concern about the effects of climate change, using innovative materials to help students understand how Earth's systems connect with each other is…

  2. How life shaped Earth.

    Science.gov (United States)

    Gross, Michael

    2015-10-01

    Earth is much more complex than all the other solar system objects that we know. Thanks to its rich and diverse geology, our planet can offer habitats to a wide range of living species. Emerging insights suggest that this is not just a happy coincidence, but that life itself has in many ways helped to shape the planet. PMID:26726334

  3. "Galileo Calling Earth..."

    Science.gov (United States)

    National Aeronautics and Space Administration, Washington, DC.

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

  4. Artificial earth satellites

    Directory of Open Access Journals (Sweden)

    V. R. Thiruvenkatachar

    1958-10-01

    Full Text Available A general discussion is given of the scientific and technological problems involved in the launching of earth satellites, covering various aspects such as the dynamical relationships involved, the propulsion and guidance systems, tracking and data transmission etc. The possible uses of satellites for scientific research as well as some of the likely future developments are also briefly indicated.

  5. Earth as art 4

    Science.gov (United States)

    U.S. Geological Survey

    2016-01-01

    Landsat 8 is the latest addition to the long-running series of Earth-observing satellites in the Landsat program that began in 1972. The images featured in this fourth installment of the Earth As Art collection were all acquired by Landsat 8. They show our planet’s diverse landscapes with remarkable clarity.Landsat satellites see the Earth as no human can. Not only do they acquire images from the vantage point of space, but their sensors record infrared as well as visible wavelengths of light. The resulting images often reveal “hidden” details of the Earth’s land surface, making them invaluable for scientific research.As with previous Earth As Art exhibits, these Landsat images were selected solely for their aesthetic appeal. Many of the images have been manipulated to enhance color variations or details. They are not intended for scientific interpretation—only for your viewing pleasure. What do you see in these unique glimpses of the Earth’s continents, islands, and coastlines?

  6. Earth's Reflection: Albedo

    Science.gov (United States)

    Gillette, Brandon; Hamilton, Cheri

    2011-01-01

    When viewing objects of different colors, you might notice that some appear brighter than others. This is because light is reflected differently from various surfaces, depending on their physical properties. The word "albedo" is used to describe how reflective a surface is. The Earth-atmosphere has a combined albedo of about 30%, a number that is…

  7. 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.

  8. Whole-Earth Decompression Dynamics

    CERN Document Server

    Herndon, J M

    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 initial whole-Earth decompression is expected to result in a global system of major primary decompression cracks appearing in the rigid crust which persist as the basalt feeders for the global, mid-oceanic ridge system. As the Earth subsequently decompresses, the area of the Earth's surface increases by the formation of secondary decompression cracks, often located near the continental margins, presently identified as oceanic trenches. These secondary decompression cracks are subsequently in-filled with basalt, extruded fr...

  9. PREFACE: The 2nd International Conference on Geological, Geographical, Aerospace and Earth Sciences 2014 (AeroEarth 2014)

    Science.gov (United States)

    Lumban Gaol, Ford; Soewito, Benfano

    2015-01-01

    The 2nd International Conference on Geological, Geographical, Aerospace and Earth Sciences 2014 (AeroEarth 2014), was held at Discovery Kartika Plaza Hotel, Kuta, Bali, Indonesia during 11 - 12 October 2014. The AeroEarth 2014 conference aims to bring together researchers and engineers from around the world. 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. 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 98 papers and after rigorous review, 17 papers were accepted. The participants come from eight countries. There are four Parallel Sessions and two invited 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 contributions. Finally, we would like to thank the conference chairmen, the members of the steering committee, the organizing committee

  10. 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

  11. Solid Earth Science ESDR System

    Science.gov (United States)

    Kedar, S.; Bock, Y.; Moore, A. W.; Squibb, M. B.; Liu, Z.; Hasse, J.; Fang, P.

    2013-12-01

    The Solid Earth Science ESDR System (SESES) provides mature, long-term calibrated and validated Earth System Data Records (ESDRs) that support NASA's Earth Surface and Interiors (ESI) focus area, routinely processing data from Earthscope's Plate Boundary Observatory GPS network, NASA's Real-time Earthquake Analysis for Disaster Mitigation network (READI), as well as from several global GPS networks. The project, which was initiated in 2006, provides multi-decade calibrated and validated GPS-derived deformation time series and deformation vectors, based on daily GPS data. The time series are a unique product in terms of number of stations and duration (over 20 years), and have been modeled and catalogued for coseismic, postseismic and transient deformation, as well as instrumental offsets. Calibration and validation of the GPS measured deformation time series are done through a combined solution of two independently derived GPS position time series. Improved sensitivity to real signals is provided by a Principal Component Analysis tool that is routinely applied to the Western North America time series. At its current stage SESES is in the process of generating and distributing the following new ESDRs: (a) Troposphere delay time series for calibrating atmospheric delay errors in Interferometric Synthetic Aperture Radar (InSAR) that are one of the limiting InSAR error sources. (b) Precipitable Water Vapor (PWV) time series for use in Probable Maximum Precipitation studies, historical weather event analysis, and studies of long-term water vapor trends. (c) Fusion of GPS and seismic measurements at collocated stations to estimate three-dimensional high-rate displacement time series with mm precision, during significant historic seismic events (e.g., 2003 Mw 8.3 Tokachi-oki earthquake in Japan; 2010 Mw 7.2 El Mayor-Cucapah earthquake in northern Baja California; 2011 Mw 9.0 Tohoku-oki earthquake in Japan) and new events during the project duration. Data sets to be used

  12. Earth Day 2010: Earth Day 40th Anniversary Poster

    OpenAIRE

    Nowacka, Izabela

    2010-01-01

    EGJ Issue 30 Earth Day 2010 ISSN 1076-7975 In celebration of 40th Earth Day the Electronic Green Journal presents one contemporary and twelve posters from 1970s focusing on ecology and the environment.

  13. Modeling Earth Albedo for Satellites in Earth Orbit

    OpenAIRE

    Bhanderi, Dan; Bak, Thomas

    2005-01-01

    Many satellite are influences by the Earthøs albedo, though very few model schemes exist.in order to predict this phenomenon. Earth albedo is often treated as noise, or ignored completely. When applying solar cells in the attitude hardware, Earth albedo can cause the attitude estimate to deviate with as much as 20 deg. Digital Sun sensors with Earth albedo correction in hardware exist, but are expensive. In addition, albedo estimates are necessary in thermal calculations and power budgets. We...

  14. Earth Science Multimedia Theater

    Science.gov (United States)

    Hasler, A. F.

    1998-01-01

    The presentation will begin with the latest 1998 NASA Earth Science Vision for the next 25 years. A compilation of the 10 days of animations of Hurricane Georges which were supplied daily on NASA to Network television will be shown. NASA's visualizations of Hurricane Bonnie which appeared in the Sept 7 1998 issue of TIME magazine. Highlights will be shown from the NASA hurricane visualization resource video tape that has been used repeatedly this season on network TV. Results will be presented from a new paper on automatic wind measurements in Hurricane Luis from 1 -min GOES images that will appear in the October BAMS. The visualizations are produced by the Goddard Visualization & Analysis Laboratory, and Scientific Visualization Studio, as well as other Goddard and NASA groups using NASA, NOAA, ESA, and NASDA Earth science datasets. Visualizations will be shown from the "Digital-HyperRes-Panorama" Earth Science ETheater'98 recently presented in Tokyo, Paris and Phoenix. The presentation in Paris used a SGI/CRAY Onyx Infinite Reality Super Graphics Workstation at 2560 X 1024 resolution with dual synchronized video Epson 71 00 projectors on a 20ft wide screen. Earth Science Electronic Theater '999 is being prepared for a December 1 st showing at NASA HQ in Washington and January presentation at the AMS meetings in Dallas. The 1999 version of the Etheater will be triple wide with at resolution of 3840 X 1024 on a 60 ft wide screen. Visualizations will also be featured from the new Earth Today Exhibit which was opened by Vice President Gore on July 2, 1998 at the Smithsonian Air & Space Museum in Washington, as well as those presented for possible use at the American Museum of Natural History (NYC), Disney EPCOT, and other venues. New methods are demonstrated for visualizing, interpreting, comparing, organizing and analyzing immense Hyperimage remote sensing datasets and three dimensional numerical model results. We call the data from many new Earth sensing satellites

  15. Metal-silicate partitioning during core formation on super-Earths

    Science.gov (United States)

    Schaefer, L. K.; Jacobsen, S. B.; Petaev, M. I.; Sasselov, D. D.; Remo, J. L.

    2015-12-01

    Separation of the Earth into a rocky mantle and metallic Fe core is a problem long studied in the planetary science community (e.g. [1]). The timing of core formation influences the abundances of the siderophile elements found in the Earth's mantle, and the mechanism of core formation influences the degree of chemical equilibration between the rocky mantle and the core at the time of metal separation. However, limited work has been done on formation of metallic cores and its effects on mantle chemistry in rocky planets larger than the Earth. Super-Earths, exoplanets with masses up to ~ 5 Earth masses and radii up to ~1.6-1.7 Earth radii, have significantly larger internal pressures and consequently higher internal temperatures than the Earth, therefore conclusions from Earth-centric studies of core formation may be erroneous. Partitioning coefficients for many of the relevant elements (e.g. Fe, Ni, Si, O, etc.) are available in the literature, but only to relatively low pressures. The relevant pressures for super-Earths are significantly larger. However, data on Fe-O-Ni-Si partitioning at pressures (200-500 GPa) and temperatures relevant to super-Earths have been measured by laser-induced shocks with the ZBL laser at Sandia National Laboratory with a method described in [2]. We will present a model which integrates this data with lower pressure partition coefficients from the literature (e.g. [3],[4],[5]), with special emphasis on Fe and O, to describe partitioning behavior at high pressures and discuss its implications for core size and composition on rocky super-Earths. [1] Ringwood, A.E. (1977) Geochem. J. 11, 111-135. [2] Remo, J.L., Petaev, M.I., Jacobsen, S. B. (2008) LPSC abstract, 1420. [3] Frost, D.J. et al. (2010) JGR, B02202. [4] Kombayashi, T. (2014) JGR, 4164-4177. [5] Rubie, D.C. et al. (2011) EPSL, 301, 31-42. [5

  16. Towards magnetic sounding of the Earth's core by an adjoint method

    Science.gov (United States)

    Li, K.; Jackson, A.; Livermore, P. W.

    2013-12-01

    Earth's magnetic field is generated and sustained by the so called geodynamo system in the core. Measurements of the geomagnetic field taken at the surface, downwards continued through the electrically insulating mantle to the core-mantle boundary (CMB), provide important constraints on the time evolution of the velocity, magnetic field and temperature anomaly in the fluid outer core. The aim of any study in data assimilation applied to the Earth's core is to produce a time-dependent model consistent with these observations [1]. Snapshots of these ``tuned" models provide a window through which the inner workings of the Earth's core, usually hidden from view, can be probed. We apply a variational data assimilation framework to an inertia-free magnetohydrodynamic system (MHD) [2]. Such a model is close to magnetostrophic balance [3], to which we have added viscosity to the dominant forces of Coriolis, pressure, Lorentz and buoyancy, believed to be a good approximation of the Earth's dynamo in the convective time scale. We chose to study the MHD system driven by a static temperature anomaly to mimic the actual inner working of Earth's dynamo system, avoiding at this stage the further complication of solving for the time dependent temperature field. At the heart of the models is a time-dependent magnetic field to which the core-flow is enslaved. In previous work we laid the foundation of the adjoint methodology, applied to a subset of the full equations [4]. As an intermediate step towards our ultimate vision of applying the techniques to a fully dynamic mode of the Earth's core tuned to geomagnetic observations, we present the intermediate step of applying the adjoint technique to the inertia-free Navier-Stokes equation in continuous form. We use synthetic observations derived from evolving a geophysically-reasonable magnetic field profile as the initial condition of our MHD system. Based on our study, we also propose several different strategies for accurately

  17. Appetite and energy balancing.

    Science.gov (United States)

    Rogers, Peter J; Brunstrom, Jeffrey M

    2016-10-01

    pleasure of eating it. The latter, which is similar to food reward, is determined primarily by the state of emptiness of the gut and food liking related to the food's sensory qualities and macronutrient value and the individual's dietary history. Importantly, energy density adds value because energy dense foods are less satiating kJ for kJ and satiation limits further intake. That is, energy dense foods promote energy intake by virtue (1) of being more attractive and (2) having low satiating capacity kJ for kJ, and (1) is partly a consequence of (2). Energy storage is adapted to feast and famine and that includes unevenness over time of the costs of obtaining and ingesting food compared with engaging in other activities. However, in very low-cost food environments with energy dense foods readily available, risk of obesity is high. This risk can be and is mitigated by dietary restraint, which in its simplest form could mean missing the occasional meal. Another strategy we discuss is the energy dilution achieved by replacing some sugar in the diet with low-calorie sweeteners. Perhaps as or more significant, though, is that belief in short-term energy balancing (the energy depletion model) may undermine attempts to eat less. Therefore, correcting narratives of eating to be consistent with biological reality could also assist with weight control.

  18. Cautions Concerning Electronic Analytical Balances.

    Science.gov (United States)

    Johnson, Bruce B.; Wells, John D.

    1986-01-01

    Cautions chemists to be wary of ferromagnetic samples (especially magnetized samples), stray electromagnetic radiation, dusty environments, and changing weather conditions. These and other conditions may alter readings obtained from electronic analytical balances. (JN)

  19. An Oscillating Magnet Watt Balance

    CERN Document Server

    Ahmedov, H

    2015-01-01

    We establish the principles for a new generation of simplified and accurate watt balances in which an oscillating magnet generates Faraday's voltage in a stationary coil. A force measuring system and a mechanism providing vertical movements of the magnet are completely independent in an oscillating magnet watt balance. This remarkable feature allows to establish the link between the Planck constant and a macroscopic mass by a one single experiment. Weak dependence on variations of environmental and experimental conditions, weak sensitivity to ground vibrations and temperature changes, simple force measuring procedure, small sizes and other useful features offered by the novel approach considerably reduce the complexity of the experimental setup. We formulate the oscillating magnet watt balance principle and establish the measurement procedure for the Planck constant. We discuss the nature of oscillating magnet watt balance uncertainties and give a brief description of the National Metrology Institute (UME) wa...

  20. Efficient codes and balanced networks.

    Science.gov (United States)

    Denève, Sophie; Machens, Christian K

    2016-03-01

    Recent years have seen a growing interest in inhibitory interneurons and their circuits. A striking property of cortical inhibition is how tightly it balances excitation. Inhibitory currents not only match excitatory currents on average, but track them on a millisecond time scale, whether they are caused by external stimuli or spontaneous fluctuations. We review, together with experimental evidence, recent theoretical approaches that investigate the advantages of such tight balance for coding and computation. These studies suggest a possible revision of the dominant view that neurons represent information with firing rates corrupted by Poisson noise. Instead, tight excitatory/inhibitory balance may be a signature of a highly cooperative code, orders of magnitude more precise than a Poisson rate code. Moreover, tight balance may provide a template that allows cortical neurons to construct high-dimensional population codes and learn complex functions of their inputs.

  1. Risk, Balanced Skills and Entrepreneurship

    OpenAIRE

    Hsieh, C.; Parker, S.C.; Praag, van, B.

    2011-01-01

    This paper proposes that risk aversion encourages individuals to invest in balanced skill profiles, making them more likely to become entrepreneurs. By not having taken this possible linkage into account, previous research has underestimated the impacts both of risk aversion and balanced skills on the likelihood individuals choose entrepreneurship. Data on Dutch university graduates provides evidence which supports this contention. It thereby raises the possibility that even risk-averse peopl...

  2. Balancer effects in opinion dynamics

    CERN Document Server

    Cheon, Taksu

    2016-01-01

    We introduce a novel type of contrarian agent, the balancer, to Galam model of opinion dynamics, in order to account for the skepticism over one-sidedness and for the sense of fairness. We find that the inclusion of balancers along with floaters and inflexibles brings about a critical point on parametric plane of the dynamical system, which results in the new kind of stable final states of the opinion dynamics, that seem to capture several intriguing features found often in mature democracies.

  3. Internet Load and Traffic Balancing

    Institute of Scientific and Technical Information of China (English)

    李文正; 郭巧; 郭为民

    2005-01-01

    Load and traffic balancing for the Internet are analyzed. An intelligent domain name system(DNS) policy for the control and management of content distribution networks (CDN) is presented. An CDNs network based Urtitech IntelliDNS is built, and performance of the network in realizing traffic and load balancing is measured. It is proved that CDNs provide a valuable service and the methods are feasible.

  4. Balancing local budgets in Romania

    OpenAIRE

    Attila GYÖRGY

    2014-01-01

    Local budgets in Romania are balanced with revenues transferred from state budget according to the criterions laid down in the Local Public Finance Act. These criterions are focusing on the financial capacity, population and surface, each local budget getting balancing amounts inversely with the administrative unit’s wellness and directly to size. The repartition algorithm is used for more than a decade, but periodically it was revised in order to be better folded to fiscal policy and economi...

  5. Electric power balance sheet 2012

    International Nuclear Information System (INIS)

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

  6. VALUE BALANCE IN CONSUMER PROTECTION

    OpenAIRE

    Dahsan Hasan

    2015-01-01

    This research aims to describe how the realization of ' Balance ' in the Consumer Protection Act, describes how the responsibility of the parties (consumers, businessmen and the Government) so that it can realize the value of the balance in the protection of consumer, Research conducted in the framework of the preparation of this dissertation is to type the socio-juridical, in addition to researching the secondary legal materials in the form of legal regulations, manual and electronic law lib...

  7. Hatha yoga on body balance

    OpenAIRE

    Erick Tadeu Prado; Vagner Raso; Renata Coelho Scharlach; Cristiane Akemi Kasse

    2014-01-01

    Background: A good body balance requires a proper function of vestibular, visual, and somatosensory systems which can be reach with exercise practice and/or yoga. Aim: To determine the effects of a 5-month hatha yoga training program on body balance in young adults. Materials and Methods: This study used a controlled, nonrandomized design, where the experimental group underwent a 5-month training program and were then compared with the control group that had a sedentary lifestyle. A c...

  8. Chemical pressure

    OpenAIRE

    Hauser, Andreas; Amstutz, Nahid; Delahaye, Sandra; Sadki, Asmaâ; Schenker, Sabine; Sieber, Regula; Zerara, Mohamed

    2002-01-01

    The physical and photophysical properties of three classic transition metal complexes, namely [Fe(bpy)3]2+, [Ru(bpy)3]2+, and [Co(bpy)3]2+, can be tuned by doping them into a variety of inert crystalline host lattices. The underlying guest-host interactions are discussed in terms of a chemical pressure.

  9. China Rare Earth Market Review

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    @@ Active demands from downstream industry drove the price rise of rare earth products in Chinese domestic marketrecently, particularly didymium and dysprosium products. Prices of other rare earth products remained stable.

  10. Mirador - Earth Surface and Interior

    Data.gov (United States)

    National Aeronautics and Space Administration — Earth Science data access made simple. The goal of the Earth Surface and Interior focus area is to assess, mitigate and forecast the natural hazards that affect...

  11. China Rare Earth Market Review

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    @@ February, 2010 Rare earth separation plants and downstream producers like NdFeB magnetic materials and phosphor materials successively ceased production due to Spring Festival, Chinese New Year. Transactions in rare earth market were few affected by public holidays.

  12. Life Before Earth

    CERN Document Server

    Sharov, Alexei A

    2013-01-01

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

  13. Physics of the Earth

    Science.gov (United States)

    Stacey, Frank D.; Davis, Paul M.

    he fourth edition of Physics of the Earth maintains the original philosophy of this classic graduate textbook on fundamental solid earth geophysics, while being completely revised, updated, and restructured into a more modular format to make individual topics even more accessible. Building on the success of previous editions, which have served generations of students and researchers for nearly forty years, this new edition will be an invaluable resource for graduate students looking for the necessary physical and mathematical foundations to embark on their own research careers in geophysics. Several completely new chapters have been added and a series of appendices, presenting fundamental data and advanced mathematical concepts, and an extensive reference list, are provided as tools to aid readers wishing to pursue topics beyond the level of the book. Over 140 student exercises of varying levels of difficulty are also included, and full solutions are available online at www.cambridge.org/9780521873628.

  14. NASA Benefits Earth

    Science.gov (United States)

    Robinson, Julie A.

    2009-01-01

    This slide presentation reviews several ways in which NASA research has benefited Earth and made life on Earth better. These innovations include: solar panels, recycled pavement, thermometer pill, invisible braces for straightening teeth, LASIK, aerodynamic helmets and tires for bicycles, cataract detection, technology that was used to remove Anthrax spores from mail handling facilities, study of atomic oxygen erosion of materials has informed the restoration of artwork, macroencapsulation (a potential mechanism to deliver anti cancer drugs to specific sites), and research on a salmonella vaccine. With research on the International Space Station just beginning, there will be opportunities for entrepreneurs and other government agencies to access space for their research and development. As well as NASA continuing its own research on human health and technology development.

  15. Heat-pipe Earth.

    Science.gov (United States)

    Moore, William B; Webb, A Alexander G

    2013-09-26

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

  16. Diagnosing and Predicting the Earth's Health via Ecological Network Analysis

    OpenAIRE

    Zi-Ke Zhang; Ye Sun; Chu-Xu Zhang; Kuan Fang; Xiang Xu; Chuang Liu; Xueqi Wang; Kui Zhang

    2013-01-01

    Ecological balance is one of the most attractive topics in biological, environmental, earth sciences, and so on. However, due to the complexity of ecosystems, it is not easy to find a perfect way to conclusively explain all the potential impacts. In this paper, by considering several important elements, we seek to build a dynamic network model to predict the Earth’s health, trying to identify and explain how the human behavior and policies affect the model results. We firstly empirically anal...

  17. The Evolution and Future of Earth's Nitrogen Cycle

    DEFF Research Database (Denmark)

    Canfield, Donald Eugene; Glazer, Alexander N.; Falkowski, Paul G.

    2010-01-01

    Atmospheric reactions and slow geological processes controlled Earth's earliest nitrogen cycle, and by similar to 2.7 billion years ago, a linked suite of microbial processes evolved to form the modern nitrogen cycle with robust natural feedbacks and controls. Over the past century, however, the ...... will ultimately restore balance to the nitrogen cycle, but the damage done by humans to the nitrogen economy of the planet will persist for decades, possibly centuries, if active intervention and careful management strategies are not initiated....

  18. Form 6 - gas balancing agreement

    International Nuclear Information System (INIS)

    In 1988, a special Committee of the Rocky Mountain Mineral Law Foundation undertook a project to draft a model from gas balancing agreement. This project was initiated at the request of a number of Foundation members who felt that a model form gas balancing agreement would facilitate the negotiation of operating agreement, since gas balancing issues had become sticking points in the process. The Committee was composed of attorneys representing a wide cross-section of the oil and gas industry including both major and independent oil companies, production companies with interstate pipeline affiliates, and private practitioners. The Committee attempted to address the more controversial issues in gas balancing with optional provisions in the Form. To facilitate the negotiation process, the number of optional provisions was minimized. This form may be used as an Appendix to the new A.A.P.L. Form 610-1989 Model Form Operating Agreement. This book includes provision of this Form which are: Ownership of gas production; Balancing of production accounts; Cash balancing upon depletion; Deliverability tests; Nominations; Statements; Payment of taxes; Operating expenses; Overproducing allowable; Payment of leasehold burdens; Operator's liability; Successors and assigns; Audits; Arbitration; and Operator's fees

  19. Superhydrophobic diatomaceous earth

    Science.gov (United States)

    Simpson, John T.; D'Urso, Brian R.

    2012-07-10

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

  20. Testing MOND on Earth

    CERN Document Server

    Ignatiev, A Yu

    2014-01-01

    MOND is one of the most popular alternatives to Dark Matter (DM). While efforts to directly detect DM in laboratories have been steadily pursued over the years, the proposed Earth-based tests of MOND are still in their infancy. Some proposals recently appeared in the literature are briefly reviewed, and it is argued that collaborative efforts of theorists and experimenters are needed to move forward in this exciting new area. Possible future directions are outlined.

  1. Earth before life

    OpenAIRE

    Marzban, Caren; Viswanathan, Raju; Yurtsever, Ulvi

    2014-01-01

    Background A recent study argued, based on data on functional genome size of major phyla, that there is evidence life may have originated significantly prior to the formation of the Earth. Results Here a more refined regression analysis is performed in which 1) measurement error is systematically taken into account, and 2) interval estimates (e.g., confidence or prediction intervals) are produced. It is shown that such models for which the interval estimate for the time origin of the genome i...

  2. Life Before Earth

    OpenAIRE

    Sharov, Alexei A.; Gordon, Richard

    2013-01-01

    An extrapolation of the genetic complexity of organisms to earlier times suggests that life began before the Earth was formed. Life may have started from systems with single heritable elements that are functionally equivalent to a nucleotide. The genetic complexity, roughly measured by the number of non-redundant functional nucleotides, is expected to have grown exponentially due to several positive feedback factors: gene cooperation, duplication of genes with their subsequent specialization,...

  3. China Rare Earth Market Review

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    September 20-30, 2011 Rare earth market remained steady recently. Quoted prices of didymium products by separation and smelting plants kept stable. Some rare earth industrial zones in Baotou, Sichuan and Ganzhou had suspended production with the intensified environmental protection control and consolidation of rare earth industry. Persons in the industry hold a positive attitude toward the rare earth market after the National Day' s holiday in China. The market will develop healthily and orderly in the future.

  4. New Theory of the Earth

    OpenAIRE

    Anderson, Don L.

    2007-01-01

    New Theory of the Earth is an interdisciplinary advanced textbook on all aspects of the interior of the Earth and its origin, composition, and evolution: geophysics, geochemistry, dynamics, convection, mineralogy, volcanism, energetics and thermal history. This is the only book on the whole landscape of deep Earth processes that ties together all the strands of the subdisciplines. This book is a complete update of Anderson’s Theory of the Earth (1989). It includes dozens of new figures a...

  5. Hunan Rare Earth Group Approved

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    <正>Following Guangdong,Guangxi,Fujian and Jiangxi,Hunan announced that it would consolidate its rare earth resources-the consolidation plan of Hunan Rare Earth Group has been approved. Consolidation of the rare earth industry of south China is in full swing.According to "Several Opinions of the State Council on Promoting the Sustainable and Healthy Development of Rare Earth Industry"(hereinafter referred to as "Several Opinions")released in 2011,

  6. Characterising Super-Earths

    Directory of Open Access Journals (Sweden)

    Valencia D.

    2011-02-01

    Full Text Available The era of Super-Earths has formally begun with the detection of transiting low-mass exoplanets CoRoT-7b and GJ 1214b. In the path of characterising super-Earths, the first step is to infer their composition. While the discovery data for CoRoT-7b, in combination with the high atmospheric mass loss rate inferred from the high insolation, suggested that it was a rocky planet, the new proposed mass values have widened the possibilities. The combined mass range 1−10 M⊕ allows for a volatile-rich (and requires it if the mass is less than 4 M⊕ , an Earth-like or a super-Mercury-like composition. In contrast, the radius of GJ 1214b is too large to admit a solid composition, thus it necessarily to have a substantial gas layer. Some evidence suggests that within this gas layer H/He is a small but non-negligible component. These two planets are the first of many transiting low-mass exoplanets expected to be detected and they exemplify the limitations faced when inferring composition, which come from the degenerate character of the problem and the large error bars in the data.

  7. The Active Solid Earth

    Science.gov (United States)

    Ebinger, Cynthia

    2016-04-01

    Dynamic processes in Earth's crust, mantle and core shape Earth's surface and magnetic field over time scales of seconds to millennia, and even longer time scales as recorded in the ca. 4 Ga rock record. Our focus is the earthquake-volcano deformation cycles that occur over human time scales, and their comparison with time-averaged deformation studies, with emphasis on mantle plume provinces where magma and volatile release and vertical tectonics are readily detectable. Active deformation processes at continental and oceanic rift and back arc zones provide critical constraints on mantle dynamics, the role of fluids (volatiles, magma, water), and plate rheology. For example, recent studies of the East African rift zone, which formed above one of Earth's largest mantle upwellings reveal that magma production and volatile release rates are comparable to those of magmatic arcs, the archetypal zones of continental crustal creation. Finite-length faults achieve some plate deformation, but magma intrusion in the form of dikes accommodates extension in continental, back-arc, and oceanic rifts, and intrusion as sills causes permanent uplift that modulates the local time-space scales of earthquakes and volcanoes. Volatile release from magma intrusion may reduce fault friction and permeability, facilitating aseismic slip and creating magma pathways. We explore the implications of active deformation studies to models of the time-averaged structure of plume and extensional provinces in continental and oceanic plate settings.

  8. Earth System Monitoring, Introduction

    Science.gov (United States)

    Orcutt, John

    This section provides sensing and data collection methodologies, as well as an understanding of Earth's climate parameters and natural and man-made phenomena, to support a scientific assessment of the Earth system as a whole, and its response to natural and human-induced changes. The coverage ranges from climate change factors and extreme weather and fires to oil spill tracking and volcanic eruptions. This serves as a basis to enable improved prediction and response to climate change, weather, and natural hazards as well as dissemination of the data and conclusions. The data collection systems include satellite remote sensing, aerial surveys, and land- and ocean-based monitoring stations. Our objective in this treatise is to provide a significant portion of the scientific and engineering basis of Earth system monitoring and to provide this in 17 detailed articles or chapters written at a level for use by university students through practicing professionals. The reader is also directed to the closely related sections on Ecological Systems, Introduction and also Climate Change Modeling Methodology, Introduction as well as Climate Change Remediation, Introduction to. For ease of use by students, each article begins with a glossary of terms, while at an average length of 25 print pages each, sufficient detail is presented for use by professionals in government, universities, and industries. The chapters are individually summarized below.

  9. Sun, Earth and Sky

    CERN Document Server

    Lang, Kenneth R

    2006-01-01

    This Second Edition of Sun, Earth and Sky updates the popular text by providing comprehensive accounts of the most recent discoveries made by five modern solar spacecraft during the past decade. Their instruments have used sound waves to peer deep into the Sun’s inner regions and measure the temperature of its central nuclear reactor, and extended our gaze far from the visible Sun to record energetic outbursts that threaten Earth. Breakthrough observations with the underground Sudbury Neutrino Observatory are also included, which explain the new physics of ghostly neutrinos and solve the problematic mismatch between the predicted and observed amounts of solar neutrinos. This new edition of Sun, Earth and Sky also describes our recent understanding of how the Sun’s outer atmosphere is heated to a million degrees, and just where the Sun’s continuous winds come from. As humans we are more intimately linked with our life-sustaining Sun than with any other astronomical object, and the new edition therefore p...

  10. Afganistan and rare earths

    Directory of Open Access Journals (Sweden)

    Emilian M. Dobrescu

    2013-05-01

    Full Text Available On our planet, over a quarter of new technologies for the economic production of industrial goods, are using rare earths, which are also called critical minerals and industries that rely on these precious items being worth of an estimated nearly five trillion dollars, or 5 percent of world gross domestic product. In the near future, competition will increase for the control of rare earth minerals embedded in high-tech products. Rare minerals are in the twenty-first century what oil accounted for in the twentieth century and coal in the nineteenth century: the engine of a new industrial revolution. Future energy will be produced increasingly by more sophisticated technological equipment based not just on steel and concrete, but incorporating significant quantities of metals and rare earths. Widespread application of these technologies will result in an exponential increase in demand for such minerals, and what is worrying is that minerals of this type are almost nowhere to be found in Europe and in other industrialized countries in the world, such as U.S. and Japan, but only in some Asian countries, like China and Afghanistan.

  11. Ion Acceleration at Earth, Saturn and Jupiter and its Global Impact on Magnetospheric Structure

    Science.gov (United States)

    Brandt, Pontus

    2016-07-01

    The ion plasma pressures at Earth, Saturn and Jupiter are significant players in the electrodynamic force-balance that governs the structure and dynamics of these magnetospheres. There are many similarities between the physical mechanisms that are thought to heat the ion plasma to temperatures that even exceed those of the solar corona. In this presentation we compare the ion acceleration mechanisms at the three planetary magnetospheres and discuss their global impacts on magnetopsheric structure. At Earth, bursty-bulk flows, or "bubbles", have been shown to accelerate protons and O+ to high energies by the earthward moving magnetic dipolarization fronts. O+ ions display a more non-adiabatic energization in response to these fronts than protons do as they are energized and transported in to the ring-current region where they reach energies of several 100's keV. We present both in-situ measurements from the NASA Van Allen Probes Mission and global Energetic Neutral (ENA) images from the High-Energy Neutral Atom (HENA) Camera on board the IMAGE Mission, that illustrate these processes. The global impact on the magnetospheric structure is explored by comparing the empirical magnetic field model TS07d for given driving conditions with global plasma pressure distributions derived from the HENA images. At Saturn, quasi-periodic energization events, or large-scale injections, occur beyond about 9 RS around the post-midnight sector, clearly shown by the Ion and Neutral Atom Camera (INCA) on board the Cassini mission. In contrast to Earth, the corotational drift dominates even the energetic ion distributions. The large-scale injections display similar dipolarization front features can be found and there are indications that like at Earth the O+ responds more non-adiabatically than protons do. However, at Saturn there are also differences in that there appears to be energization events deep in the inner magnetosphere (6-9 RS) preferentially occurring in the pre

  12. 25th Space Simulation Conference. Environmental Testing: The Earth-Space Connection

    Science.gov (United States)

    Packard, Edward

    2008-01-01

    Topics covered include: Methods of Helium Injection and Removal for Heat Transfer Augmentation; The ESA Large Space Simulator Mechanical Ground Support Equipment for Spacecraft Testing; Temperature Stability and Control Requirements for Thermal Vacuum/Thermal Balance Testing of the Aquarius Radiometer; The Liquid Nitrogen System for Chamber A: A Change from Original Forced Flow Design to a Natural Flow (Thermo Siphon) System; Return to Mercury: A Comparison of Solar Simulation and Flight Data for the MESSENGER Spacecraft; Floating Pressure Conversion and Equipment Upgrades of Two 3.5kw, 20k, Helium Refrigerators; Affect of Air Leakage into a Thermal-Vacuum Chamber on Helium Refrigeration Heat Load; Special ISO Class 6 Cleanroom for the Lunar Reconnaissance Orbiter (LRO) Project; A State-of-the-Art Contamination Effects Research and Test Facility Martian Dust Simulator; Cleanroom Design Practices and Their Influence on Particle Counts; Extra Terrestrial Environmental Chamber Design; Contamination Sources Effects Analysis (CSEA) - A Tool to Balance Cost/Schedule While Managing Facility Availability; SES and Acoustics at GSFC; HST Super Lightweight Interchangeable Carrier (SLIC) Static Test; Virtual Shaker Testing: Simulation Technology Improves Vibration Test Performance; Estimating Shock Spectra: Extensions beyond GEVS; Structural Dynamic Analysis of a Spacecraft Multi-DOF Shaker Table; Direct Field Acoustic Testing; Manufacture of Cryoshroud Surfaces for Space Simulation Chambers; The New LOTIS Test Facility; Thermal Vacuum Control Systems Options for Test Facilities; Extremely High Vacuum Chamber for Low Outgassing Processing at NASA Goddard; Precision Cleaning - Path to Premier; The New Anechoic Shielded Chambers Designed for Space and Commercial Applications at LIT; Extraction of Thermal Performance Values from Samples in the Lunar Dust Adhesion Bell Jar; Thermal (Silicon Diode) Data Acquisition System; Aquarius's Instrument Science Data System (ISDS) Automated

  13. Balancing wobbles in the body sodium.

    Science.gov (United States)

    Titze, Jens; Rakova, Natalia; Kopp, Christoph; Dahlmann, Anke; Jantsch, Jonathan; Luft, Friedrich C

    2016-07-01

    Sodium balance is achieved within a matter of days and everything that enters should come out; sodium stores are of questionable relevance and sodium accumulation is accompanied by weight gain. Careful balance studies oftentimes conflicted with this view, and long-term studies suggested that total body sodium (TBNa) fluctuates independent of intake or body weight. We recently performed the opposite experiment in that we fixed sodium intake for weeks at three levels of sodium intake and collected all urine made. We found weekly (circaseptan) patterns in sodium excretion that were inversely related to aldosterone and directly related to cortisol. TBNa was not dependent on sodium intake, but instead exhibited far longer (greater than or equal to monthly) infradian rhythms independent of extracellular water, body weight or blood pressure. To discern the mechanisms further, we delved into sodium magnetic resonance imaging (Na-MRI) to identify sodium storage clinically. We found that sodium stores are greater in men than in women, increase with age and are higher in hypertensive than normotensive persons. We have suggestive evidence that these sodium stores can be mobilized, also in dialysis patients. The observations are in accordance with our findings that immune cells regulate a hypertonic interface in the skin interstitium that could serve as a protective barrier. Returning to our balance studies, we found that due to biological variability in 24-h sodium excretion, collecting urine for a day could not separate 12, 9 or 6 g/day sodium intakes with the precision of tossing a coin. Every other daily urine sampling correctly classified a 3-g difference in salt intake less than half the time, making the gold standard 24-h urine collection of little value in predicting salt intake. We suggest that wobbles in expected outcomes can lead to novel clinical insights even with respect to banal salt questions. PMID:26410883

  14. Balancing the Demands of Education and Training

    DEFF Research Database (Denmark)

    Christensen, Mette Krogh; Sørensen, Jan Kahr

    Balancing the Demands of Education and Training – A Qualitative Study on Young Male Football Talents’ Dual Careers. M. K. Christensena and J. K. Sørensenb a Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark b Department of Public Health – Sport Science, Aarhus...... of education and of elite sport. At the same time elite sportspeople in the top international sports are being placed under increasing pressure as a result of the performance optimization approaches that are now a fundamental part of competing at the national elite level, and which have resulted...... in a significant rise in the time such sporting assets spend on sport. Yet, attempting a professional career in football involves great mental and physical strains that profoundly affect the future lives of the young talents. The study presented in this paper explores how 15- to 19-year-old Danish football talents...

  15. Postural balance in low back pain patients

    DEFF Research Database (Denmark)

    Maribo, Thomas; Schiøttz-Christensen, Berit; Jensen, Lone Donbæk;

    2012-01-01

    INTRODUCTION: Altered postural control has been observed in low back pain (LBP) patients. They seem to be more dependent on vision when standing. The objective of the study was to determine concurrent and predictive validity of measures of postural stability in LBP patients. MATERIALS AND METHODS....... CONCLUSION: This first study of concurrent and predictive validity of postural balance in LBP patients revealed no association between CoP measures and pain, fear of pain, and physical function.......: Centre of Pressure (CoP) measurements were tested against pain, fear of pain, and physical function. Velocity, anterior-posterior displacement, and the Romberg Ratio obtained on a portable force platform were used as measures of postural stability. RESULTS: Baseline and 12-week follow-up results of 97...

  16. Practical application of pressure regulating technology for fire district in Meiyukou Coal Mine

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qing-feng; JIA Bao-shan

    2008-01-01

    Based on the simulated laboratory experiment of pressure balance for fire extinguishing,the pressure regulating technology was summarized for the fire district in Meiyukou Coal Mine.The technology includes three measures for air pressure regulation,namely applying the pressure regulating chamber to balance the air pressure of fire district,increasing the air pressure of the working face,and filling the ground surface fractures.A good effect was obtained to prevent and extinguish the fire.When the measures fail to increase the pressure of working face or to regulate that of air chamber,the measure to fill the ground surface fractures will play an important role.

  17. Practical application of pressure regulating technology for fire district in Meiyukou Coal Mine

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qing-feng; JIA Bao-shan

    2008-01-01

    Based on the simulated laboratory experiment of pressure balance for fire ex-tinguishing, the pressure regulating technology was summarized for the fire district in Meiyukou Coal Mine. The technology includes three measures for air pressure regulation, namely applying the pressure regulating chamber to balance the air pressure of fire district, increasing the air pressure of the working face, and filling the ground surface fractures. A good effect was obtained to prevent and extinguish the fire. When the measures fail to in-crease the pressure of working face or to regulate that of air chamber, the measure to fill the ground surface fractures will play an important role.

  18. China Rare Earth Market Review

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    @@ Supply of rare earth concentrate remained tight recently. Rare earth market exhibited rising tendency holistically Affected by tight supply of rare earth concentrate, many plants were operated under the capacity. Supply of didymium oxide got tighter and the price was on rising.

  19. Relationships between fear of falling, balance confidence, and control of balance, gait, and reactive stepping in individuals with sub-acute stroke.

    Science.gov (United States)

    Schinkel-Ivy, Alison; Inness, Elizabeth L; Mansfield, Avril

    2016-01-01

    Fear of falling is common in individuals with stroke; however, the associations between fear of falling, balance confidence, and the control of balance and gait are not well understood for this population. This study aimed to determine whether, at the time of admission to in-patient rehabilitation, specific features of balance and gait differed between individuals with stroke who did and did not report fear of falling, and whether these features were related to balance confidence. Individuals with stroke entering in-patient rehabilitation were asked if they were afraid of falling, and completed the Activities-Specific Balance Confidence Scale. Participants performed quiet standing, gait, and reactive stepping tasks, and specific measures were extracted for each (quiet standing: centre of pressure amplitude, between-limb synchronization, and Romberg quotients; gait: walking velocity, double support time, and variability measures; reactive stepping: number of steps, frequency of grasp reactions, and frequency of assists). No significant differences were identified between individuals with and without fear of falling. Balance confidence was negatively related to centre of pressure amplitude, double support time, and step time variability, and positively related to walking velocity. Low balance confidence was related to poor quiet standing balance control and cautious behavior when walking in individuals with sub-acute stroke. While the causal relationship between balance confidence and the control of balance and gait is unclear from the current work, these findings suggest there may be a role for interventions to increase balance confidence among individuals with stroke, in order to improve functional mobility. PMID:26482234

  20. Strategy for earth explorers in global earth sciences

    Science.gov (United States)

    1988-01-01

    The goal of the current NASA Earth System Science initiative is to obtain a comprehensive scientific understanding of the Earth as an integrated, dynamic system. The centerpiece of the Earth System Science initiative will be a set of instruments carried on polar orbiting platforms under the Earth Observing System program. An Earth Explorer program can open new vistas in the earth sciences, encourage innovation, and solve critical scientific problems. Specific missions must be rigorously shaped by the demands and opportunities of high quality science and must complement the Earth Observing System and the Mission to Planet Earth. The committee believes that the proposed Earth Explorer program provides a substantial opportunity for progress in the earth sciences, both through independent missions and through missions designed to complement the large scale platforms and international research programs that represent important national commitments. The strategy presented is intended to help ensure the success of the Earth Explorer program as a vital stimulant to the study of the planet.