Sample records for variable mass systems

  1. Dynamics of Variable Mass Systems

    NASA Technical Reports Server (NTRS)

    Eke, Fidelis O.

    1998-01-01

    This report presents the results of an investigation of the effects of mass loss on the attitude behavior of spinning bodies in flight. The principal goal is to determine whether there are circumstances under which the motion of variable mass systems can become unstable in the sense that their transverse angular velocities become unbounded. Obviously, results from a study of this kind would find immediate application in the aerospace field. The first part of this study features a complete and mathematically rigorous derivation of a set of equations that govern both the translational and rotational motions of general variable mass systems. The remainder of the study is then devoted to the application of the equations obtained to a systematic investigation of the effect of various mass loss scenarios on the dynamics of increasingly complex models of variable mass systems. It is found that mass loss can have a major impact on the dynamics of mechanical systems, including a possible change in the systems stability picture. Factors such as nozzle geometry, combustion chamber geometry, propellant's initial shape, size and relative mass, and propellant location can all have important influences on the system's dynamic behavior. The relative importance of these parameters on-system motion are quantified in a way that is useful for design purposes.

  2. New kinetic energy operator for variable mass systems

    NASA Astrophysics Data System (ADS)

    Vubangsi, M.; Tchoffo, M.; Fai, L. C.

    2014-06-01

    We have derived a new kinetic energy operator for studying variable mass systems. Our operator is dependent on the space deformation profile subject to the order parameter . At zeroth order, we recover the standard one-dimensional kinetic energy operator for a constant mass system while, for , the operator is interpreted as describing a system endowed with a position-dependent effective mass.

  3. On the generalized virial theorem for systems with variable mass

    NASA Astrophysics Data System (ADS)

    Ganghoffer, Jean-François; Rahouadj, Rachid

    2015-05-01

    We presently extend the virial theorem for both discrete and continuous systems of material points with variable mass, relying on developments presented in Ganghoffer (Int J Solids Struct 47:1209-1220, 2010). The developed framework is applicable to describe physical systems at very different scales, from the evolution of a population of biological cells accounting for growth to mass ejection phenomena occurring within a collection of gravitating objects at the very large astrophysical scales. As a starting basis, the field equations in continuum mechanics are written to account for a mass source and a mass flux, leading to a formulation of the virial theorem accounting for non-constant mass within the considered system. The scalar and tensorial forms of the virial theorem are then written successively in both Lagrangian and Eulerian formats, incorporating the mass flux. As an illustration, the averaged stress tensor in accreting gravitating solid bodies is evaluated based on the generalized virial theorem.

  4. Position-dependent effective mass system in a variable potential: displacement operator method

    NASA Astrophysics Data System (ADS)

    Vubangsi, M.; Tchoffo, M.; Fai, L. C.

    2014-02-01

    Within the framework of the translation operator for a quantum system with position-dependent mass, we examine the quantum state of a position-dependent mass system in a variable potential. By imposing conditions of resolvability, we arrive at a potential with a quartic and a quadratic term. It emerges naturally that the energy eigen states of the system are negative. We have found the quantum mechanical quantities: energy spectrum, eigen functions and uncertainty relation. These quantities depend on the parameters of the potential.

  5. Cataclysmic variables below the period gap: mass determinations of 14 eclipsing systems

    NASA Astrophysics Data System (ADS)

    Savoury, C. D. J.; Littlefair, S. P.; Dhillon, V. S.; Marsh, T. R.; Gänsicke, B. T.; Copperwheat, C. M.; Kerry, P.; Hickman, R. D. G.; Parsons, S. G.

    2011-08-01

    We present high-speed, three-colour photometry of the eclipsing cataclysmic variables CTCV J1300-3052, CTCV J2354-4700 and SDSS J115207.00+404947.8. These systems have orbital periods of 128.07, 94.39 and 97.52 min, respectively, placing all three systems below the observed 'period gap' for cataclysmic variables. For each system we determine the system parameters by fitting a parametrized model to the observed eclipse light curve by ?2 minimization. We also present an updated analysis of all other eclipsing systems previously analysed by our group. The updated analysis utilizes Markov chain Monte Carlo techniques which enable us to arrive confidently at the best fits for each system with more robust determinations of our errors. A new bright-spot model is also adopted, that allows better modelling of bright-spot dominated systems. In addition, we correct a bug in the old code which resulted in the white dwarf radius being underestimated, and consequently both the white dwarf and donor mass being overestimated. New donor masses are generally between 1? and 2? of those originally published, with the exception of SDSS 1502 (-2.9?, ?Mr=-0.012 M?) and DV UMa (+6.1?, ?Mr=+0.039 M?). We note that the donor mass of SDSS 1501 has been revised upwards by 0.024 M? (+1.9?). This system was previously identified as having evolved past the minimum orbital period for cataclysmic variables, but the new mass determination suggests otherwise. Our new analysis confirms that SDSS 1035 and SDSS 1433 have evolved past the period minimum for cataclysmic variables, corroborating our earlier studies. We find that the radii of donor stars are oversized when compared to theoretical models, by approximately 10 per cent. We show that this can be explained by invoking either enhanced angular momentum loss, or by taking into account the effects of star spots. We are unable to favour one cause over the other, as we lack enough precise mass determinations for systems with orbital periods between 100 and 130 min, where evolutionary tracks begin to diverge significantly. We also find a strong tendency towards high white dwarf masses within our sample, and no evidence for any He-core white dwarfs. The dominance of high-mass white dwarfs implies that erosion of the white dwarf during the nova outburst must be negligible, or that not all of the mass accreted is ejected during nova cycles, resulting in the white dwarf growing in mass.

  6. Earth System Data Records of Mass Transport from Time-Variable Gravity Data

    NASA Astrophysics Data System (ADS)

    Zlotnicki, V.; Talpe, M.; Nerem, R. S.; Landerer, F. W.; Watkins, M. M.

    2014-12-01

    Satellite measurements of time variable gravity have revolutionized the study of Earth, by measuring the ice losses of Greenland, Antarctica and land glaciers, changes in groundwater including unsustainable losses due to extraction of groundwater, the mass and currents of the oceans and their redistribution during El Niño events, among other findings. Satellite measurements of gravity have been made primarily by four techniques: satellite tracking from land stations using either lasers or Doppler radio systems, satellite positioning by GNSS/GPS, satellite to satellite tracking over distances of a few hundred km using microwaves, and through a gravity gradiometer (radar altimeters also measure the gravity field, but over the oceans only). We discuss the challenges in the measurement of gravity by different instruments, especially time-variable gravity. A special concern is how to bridge a possible gap in time between the end of life of the current GRACE satellite pair, launched in 2002, and a future GRACE Follow-On pair to be launched in 2017. One challenge in combining data from different measurement systems consists of their different spatial and temporal resolutions and the different ways in which they alias short time scale signals. Typically satellite measurements of gravity are expressed in spherical harmonic coefficients (although expansions in terms of 'mascons', the masses of small spherical caps, has certain advantages). Taking advantage of correlations among spherical harmonic coefficients described by empirical orthogonal functions and derived from GRACE data it is possible to localize the otherwise coarse spatial resolution of the laser and Doppler derived gravity models. This presentation discusses the issues facing a climate data record of time variable mass flux using these different data sources, including its validation.

  7. Variability of mass-size relationships in tropical Mesoscale Convective Systems

    NASA Astrophysics Data System (ADS)

    Fontaine, Emmanuel; Leroy, Delphine; Delanoë, Julien; Dupuy, Régis; Lilie, Lyle; Strapp, Walter; Protat, Alain; Schwarzenböeck, Alfons

    2015-04-01

    The mass of individual ice hydrometeors in Mesoscale Convective Systems (MCS) has been investigated in the past using different methods in order to retrieve power law type mass-size relationships m(D) with m = ? D^?. This study focuses on the variability of mass-size relationships in different types of MCS. Three types of tropical MCS were sampled during different airborne campaigns: (i) continental MCS during the West African monsoon (Megha-Tropique 2010), (ii) oceanic MCS over the Indian Ocean (Megha-Tropique 2011), and (iii) coastal MCS during the North-Australian monsoon (HAIC-HIWC). Mass-size relationships of ice hydrometeors are derived from a combined analysis of particle images from 2D-array probes and associated reflectivity factors measured with a Doppler cloud radar (94GHz) on the same research aircraft. A theoretical study of numerous hydrometeor shapes simulated in 3D and arbitrarily projected on a 2D plan allowed to constrain the exponent ? of the m(D) relationship as a function of the derived surface-diameter relationship S(D), which is likewise written as a power law. Since S(D) always can be determined for real data from 2D optical array probes or other particle imagers, the evolution of the m(D) exponent ? can be calculated along the flight trajectory. Then the pre-factor ? of m(D) is constrained from theoretical simulations of the radar reflectivity factor matching the measured reflectivity factor along the aircraft trajectory. Finally, the Condensed Water Content (CWC) is deduced from measured particle size distributions (PSD) and retrieved m(D) relationships along the flight trajectory. Solely for the HAIC-HIWC campaign (North Australian Monsoon) a bulk reference measurement (IKP instrument) of high CWC could be performed in order to compare with the above described CWC deduced from ice hydrometeor images and reflectivity factors. Both CWC are coherent. Mean profiles of m(D) coefficients, PSD, and CWC are calculated as a function of the temperature. For the three types of MCS, it is shown that the variability of m(D) coefficients is correlated with the variability of the temperature and that the mass of ice hydrometeors for a given size decreases with decreasing temperature. Finally, the vertical variability of m(D) and PSD will be further differentiated, when separating the dataset horizontally with respect to the convective core of the MCS using the definition of a convective index.

  8. Video analysis of sliding chains: A dynamic model based on variable-mass systems

    NASA Astrophysics Data System (ADS)

    Moreno, R.; Page, A.; Riera, J.; Hueso, J. L.

    2015-06-01

    This paper presents an experimental study of the dynamics of a chain sliding off of a table, using video analysis to test a theoretical model. The model consists of two variable-mass subsystems, with friction between the chain and the table and assumes that all links move at the same speed. In order to check the model, the chain position x(t) is obtained using video analysis. The smoothed function x(t) and its derivatives v(t) and a(t) are numerically computed using a local regression algorithm. In this way, the differential equation governing the motion can be directly tested, instead of comparing the position with the solution of the differential equation. Our procedure is very sensitive to deviations between the model and reality, so we can detect the point at which the chain ceases to be in tension and the model is no longer valid. This experiment shows students the limitations of simplified models and offers an opportunity to assess a model's range of validity.

  9. Earth\\'s Mass Variability

    E-print Network

    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.

  10. The initial mass function of stars: evidence for uniformity in variable systems.

    PubMed

    Kroupa, Pavel

    2002-01-01

    The distribution of stellar masses that form in one star formation event in a given volume of space is called the initial mass function (IMF). The IMF has been estimated from low-mass brown dwarfs to very massive stars. Combining IMF estimates for different populations in which the stars can be observed individually unveils an extraordinary uniformity of the IMF. This general insight appears to hold for populations including present-day star formation in small molecular clouds, rich and dense massive star-clusters forming in giant clouds, through to ancient and metal-poor exotic stellar populations that may be dominated by dark matter. This apparent universality of the IMF is a challenge for star formation theory, because elementary considerations suggest that the IMF ought to systematically vary with star-forming conditions. PMID:11778039

  11. PHYSICS OF ELEMENTARY PARTICLES AND FIELDS: Mei Symmetries and Lie Symmetries for Nonholonomic Controllable Mechanical Systems with Relativistic Rotational Variable Mass

    NASA Astrophysics Data System (ADS)

    Xia, Li-Li; Li, Yuan-Cheng; Wang, Xian-Jun

    2009-06-01

    The Mei symmetries and the Lie symmetries for nonholonomic controllable mechanical systems with relativistic rotational variable mass are studied. The differential equations of motion of the systems are established. The definition and criterion of the Mei symmetries and the Lie symmetries of the system are studied respectively. The necessary and sufficient condition under which the Mei symmetry is Lie symmetry is given. The condition under which the Mei symmetries can be led to a new kind of conserved quantity and the form of the conserved quantity are obtained. An example is given to illustrate the application of the results.

  12. Variable addressability imaging systems

    NASA Astrophysics Data System (ADS)

    Kubala, Kenneth Scott

    The use of variable addressability for creating an optimum human-machine interface is investigated. Current wide field optical systems present more information to the human visual system than it has the capacity to perceive. The axial resolution, and/or the field of view can be increased by minimizing the difference between what the eye can perceive and what the system presents. The variable addressability function was developed through the use of a human factors experiment that characterized the position of the eye during the simulated use of a binocular system. Applying the variable addressability function to a conventional optical design required the development of a new metric for evaluating the expected performance of the variable addressability system. The new metric couples psycho-visual data and traditional optical data in order to specify the required performance of the variable addressability system. A non-linear mapping of the pixels is required in order to have the system work most efficiently with the human visual system, while also compensating for eye motion. The non-linear mapping function, which is the backbone of the variable addressability technique, can be created using optical distortion. The lens and system design is demonstrated in two different spectral bands. One of the designs was fabricated, tested, and assembled into a prototype. Through a second human factors study aimed at measuring performance, the variable addressability prototype was directly compared to a uniform addressability prototype, quantifying the difference in performance for the two prototypes. The human factors results showed that the variable addressability prototype provided better resolution 13% of the time throughout the experiment, but was 15% slower in use than the uniform addressability prototype.

  13. Black hole mass and variability in quasars

    E-print Network

    M. Wold; M. S. Brotherton; Z. Shang

    2008-07-24

    We report on a study that finds a positive correlation between black hole mass and variability amplitude in quasars. Roughly 100 quasars at zBlack hole masses were estimated with the virial method using the broad Hbeta line, and variability was characterized from the QUEST1 light curves. The correlation between black hole mass and variability amplitude is significant at the 99% level or better and does not appear to be caused by obvious selection effects inherent to flux-limited samples. It is most evident for rest frame time lags of the order a few months up to the QUEST1 maximum temporal resolution of about 2 years. The correlation between black hole mass and variability amplitude means that the more massive black holes have larger percentage flux variations. Over 2-3 orders of magnitude in black hole mass, the amplitude increases by approximately 0.2 mag. A likely explanation for the correlation is that the more massive black holes are starving and produce larger flux variations because they do not have a steady inflow of gaseous fuel. Assuming that the variability arises from changes in the accretion rate Li & Cao [8] show that flux variations similar to those observed are expected as a consequence of the more massive black holes having cooler accretion disks.

  14. Comprehensive theory of the Deans' switch as a variable flow splitter: fluid mechanics, mass balance, and system behavior.

    PubMed

    Boeker, Peter; Leppert, Jan; Mysliwietz, Bodo; Lammers, Peter Schulze

    2013-10-01

    The Deans' switch is an effluent switching device based on controlling flows of carrier gas instead of mechanical valves in the analytical flow path. This technique offers high inertness and a wear-free operation. Recently new monolithic microfluidic devices have become available. In these devices the whole flow system is integrated into a small metal device with low thermal mass and leak-tight connections. In contrast to a mechanical valve-based system, a flow-controlled system is more difficult to calculate. Usually the Deans' switch is used to switch one inlet to one of two outlets, by means of two auxiliary flows. However, the Deans' switch can also be used to deliver the GC effluent with a specific split ratio to both outlets. The calculation of the split ratio of the inlet flow to the two outlets is challenging because of the asymmetries of the flow resistances. This is especially the case, if one of the outlets is a vacuum device, such as a mass spectrometer, and the other an atmospheric detector, e.g. a flame ionization detector (FID) or an olfactory (sniffing) port. The capillary flows in gas chromatography are calculated with the Hagen-Poiseuille equation of the laminar, isothermal and compressible flow in circular tubes. The flow resistances in the new microfluidic devices have to be calculated with the corresponding equation for rectangular cross-section microchannels. The Hagen-Poiseuille equation underestimates the flow to a vacuum outlet. A corrected equation originating from the theory of rarefied flows is presented. The calculation of pressures and flows of a Deans' switch based chromatographic system is done by the solution of mass balances. A specific challenge is the consideration of the antidiffusion resistor between the two auxiliary gas lines of the Deans' switch. A full solution for the calculation of the Deans' switch including this restrictor is presented. Results from validation measurements are in good accordance with the developed theories. A spreadsheet-based flow calculator is part of the Supporting Information. PMID:23980824

  15. White dwarf masses in cataclysmic variables

    E-print Network

    Wijnen, T P G; Schreiber, M R

    2015-01-01

    The white dwarf (WD) mass distribution of cataclysmic variables (CVs) has recently been found to dramatically disagree with the predictions of the standard CV formation model. The high mean WD mass among CVs is not imprinted in the currently observed sample of CV progenitors and cannot be attributed to selection effects. Two possibilities have been put forward: either the WD grows in mass during CV evolution, or in a significant fraction of cases, CV formation is preceded by a (short) phase of thermal time-scale mass transfer (TTMT) in which the WD gains a sufficient amount of mass. We investigate if either of these two scenarios can bring theoretical predictions and observations into agreement. We employed binary population synthesis models to simulate the present intrinsic CV population. We incorporated aspects specific to CV evolution such as an appropriate mass-radius relation of the donor star and a more detailed prescription for the critical mass ratio for dynamically unstable mass transfer. We also imp...

  16. THE ORIGIN OF VARIABILITY OF THE INTERMEDIATE-MASS BLACK-HOLE ULX SYSTEM HLX-1 IN ESO 243-49

    SciTech Connect

    Lasota, J.-P. [Institut d'Astrophysique de Paris, UMR 7095 CNRS, UPMC Univ Paris 06, 98bis Boulevard Arago, 75014 Paris (France); Alexander, T. [Department of Particle Physics and Astrophysics, Faculty of Physics, Weizmann Institute of Science, P.O. Box 26, Rehovot 76100 (Israel); Dubus, G. [UJF-Grenoble 1/CNRS-INSU, Institut de Planetologie et d'Astrophysique de Grenoble (IPAG) UMR 5274, Grenoble F-38041 (France); Barret, D.; Godet, O.; Webb, N. A. [Universite de Toulouse, Universite Paul Sabatier, Observatoire Midi-Pyrenees, Institut de Recherche en Astrophysique et Planetologie (IRAP), Toulouse (France); Farrell, S. A. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH (United Kingdom); Gehrels, N., E-mail: lasota@iap.fr [NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2011-07-10

    The ultra-luminous (L{sub X} {approx}< 10{sup 42} erg s{sup -1}) intermediate-mass black-hole (IMBH) system HLX-1 in the ESO 243-49 galaxy exhibits variability with a possible recurrence time of a few hundred days. Finding the origin of this variability would constrain the still largely unknown properties of this extraordinary object. Since it exhibits a hardness-intensity behavior characteristic of black-hole X-ray transients, we have analyzed the variability of HLX-1 in the framework of the disk instability model that explains outbursts of such systems. We find that the long-term variability of HLX-1 is unlikely to be explained by a model in which outbursts are triggered by thermal-viscous instabilities in an accretion disk. Possible alternatives include the instability in a radiation-pressure-dominated disk but we argue that a more likely explanation is a modulated mass transfer due to tidal stripping of a star in an eccentric orbit around the IMBH. We consider an evolutionary scenario leading to the creation of such a system and estimate the probability of its observation. We conclude, using a simplified dynamical model of the post-collapse cluster, that no more than 1/100 to 1/10 of M{sub .} {approx}< 10{sup 4} M{sub sun} IMBHs-formed by runaway stellar mergers in the dense collapsed cores of young clusters-could have a few x1 M{sub sun} main-sequence star evolve to an asymptotic giant branch on an orbit eccentric enough for mass transfer at periapse, while avoiding collisional destruction or being scattered into the IMBH by two-body encounters. The finite but low probability of this configuration is consistent with the uniqueness of HLX-1. We note, however, that the actual response of a standard accretion disk to bursts of mass transfer may be too slow to explain the observations unless the orbit is close to parabolic (and hence even rarer). Also, increased heating, presumably linked to the highly time-dependent gravitational potential, could shorten the relevant timescales.

  17. White dwarf masses in cataclysmic variables

    NASA Astrophysics Data System (ADS)

    Wijnen, T. P. G.; Zorotovic, M.; Schreiber, M. R.

    2015-05-01

    Context. The white dwarf (WD) mass distribution of cataclysmic variables (CVs) has recently been found to dramatically disagree with the predictions of the standard CV formation model. The high mean WD mass among CVs is not imprinted in the currently observed sample of CV progenitors and cannot be attributed to selection effects. Two possibilities have been put forward to solve this issue: either the WD grows in mass during CV evolution, or in a significant fraction of cases, CV formation is preceded by a (short) phase of thermal time-scale mass transfer (TTMT) in which the WD gains a sufficient amount of mass. Aims: Here we investigate if and under which conditions a phase of TTMT before CV formation or mass growth in CVs can bring theoretical predictions and observations into agreement. Methods: We employed binary population synthesis models using the binary_c/nucsyn code to simulate the present intrinsic CV population. To that end we incorporated aspects specific to CV evolution such as an appropriate mass-radius relation of the donor star and a more detailed prescription for the critical mass ratio for dynamically unstable mass transfer. We have also implemented a previously suggested wind from the surface of the WD during TTMT and tested the idea of WD mass growth during the CV phase by arbitrarily changing the accretion efficiency. We compare the model predictions of the TTMT and the mass growth model with the characteristics of CVs derived from observed samples. Results: We find that mass growth of the WDs in CVs fails to reproduce the observed WD mass distribution. In the case of TTMT, we are able to produce a large number of massive WDs if we assume significant mass loss from the surface of the WD during the TTMT phase. However, the model still produces too many CVs with helium WDs. Moreover, the donor stars are evolved in many of these post-TTMT CVs, which contradicts the observations. Conclusions: We conclude that in our current framework of CV evolution neither TTMT nor WD mass growth can fully explain either the observed WD mass or the period distribution in CVs.

  18. Variable reluctance drive system

    SciTech Connect

    Lipo, T.A.; Liang, F.

    1995-10-17

    A variable reluctance drive system including a motor and corresponding converter for improved current commutation is described. The motor incorporates a salient pole rotor and a salient pole stator having one or more full pitch windings which operate by mutual inductance to transfer the current from the active short pitch winding following phase alignment. This increases output torque and/or speed and permits a number of simple and economical converter circuits. 17 figs.

  19. Mass Functions Density Functions Random Variables and Distribution Functions

    E-print Network

    Watkins, Joseph C.

    Mass Functions Density Functions Topic 7 Random Variables and Distribution Functions Mass Functions and Density Functions 1 / 9 #12;Mass Functions Density Functions Outline Mass Functions Density Functions 2 / 9 #12;Mass Functions Density Functions Mass Functions The (probability) mass function of a discrete

  20. Variable stars in Stellar Systems

    E-print Network

    Giuseppe Bono; Silvia Petroni; Marcella Marconi

    2002-12-07

    We discuss in detail the pulsation properties of variable stars in globular clusters (GCs) and in Local Group (LG) dwarf galaxies. Data available in the literature strongly support the evidence that we still lack a complete census of variable stars in these stellar systems. This selection bias is even more severe for small-amplitude variables such as Oscillating Blue Stragglers (OBSs) and new exotic groups of variable stars located in crowded cluster regions. The same outcome applies to large-amplitude, long-period variables as well as to RR Lyrae and Anomalous Cepheids in dwarf galaxies.

  1. Variability in properties of Salado Mass Concrete

    SciTech Connect

    Wakeley, L.D.; Harrington, P.T. [US Army Engineer Waterways Experiment Station, Vicksburg, MS (United States); Hansen, F.D. [Sandia National Labs., Albuquerque, NM (United States)

    1995-08-01

    Salado Mass Concrete (SMC) has been developed for use as a seal component in the Waste Isolation Pilot Plant. This concrete is intended to be mixed from pre-bagged materials, have an initial slump of 10 in., and remain pumpable and placeable for two hours after mixing. It is a mass concrete because it will be placed in monoliths large enough that the heat generated during cement hydration has the potential to cause thermal expansion and subsequent cracking, a phenomenon to avoid in the seal system. This report describes effects on concrete properties of changes in ratio of water to cement, batch size, and variations in characteristics of different lots of individual components of the concrete. The research demonstrates that the concrete can be prepared from laboratory-batched or pre-bagged dry materials in batches from 1.5 ft{sup 3} to 5.0 yd{sup 3}, with no chemical admixtures other than the sodium chloride added to improve bonding with the host rock, at a water-to-cement ratio ranging from 0.36 to 0.42. All batches prepared according to established procedures had adequate workability for at least 1.5 hours, and achieved or exceeded the target compressive strength of 4500 psi at 180 days after casting. Portland cement and fly ash from different lots or sources did not have a measurable effect on concrete properties, but variations in a shrinkage-compensating cement used as a component of the concrete did appear to affect workability. A low initial temperature and the water-reducing and set-retarding functions of the salt are critical to meeting target properties.

  2. Variability in properties of Salado Mass Concrete

    Microsoft Academic Search

    L. D. Wakeley; P. T. Harrington; F. D. Hansen

    1995-01-01

    Salado Mass Concrete (SMC) has been developed for use as a seal component in the Waste Isolation Pilot Plant. This concrete is intended to be mixed from pre-bagged materials, have an initial slump of 10 in., and remain pumpable and placeable for two hours after mixing. It is a mass concrete because it will be placed in monoliths large enough

  3. Variable buoyancy system metric

    E-print Network

    Jensen, Harold Franklin

    2009-01-01

    Over the past 20 years, underwater vehicle technology has undergone drastic improvements, and vehicles are quickly gaining popularity as a tool for numerous oceanographic tasks. Systems used on the vehicle to alter buoyancy, ...

  4. Hyperstability in variable structure systems

    NASA Technical Reports Server (NTRS)

    Calise, A. J.

    1980-01-01

    A variable structure control law is a discontinuous feedback law whose coefficients switch on hypersurfaces defined in the state space. Feedback systems with variable structure control laws are often referred to as variable structure systems (VSS). The main feature of VSS is the sliding motion which can occur at the intersection of the switching surfaces. Demonstrating existence and reaching in the case of vector control in n-dimensional space is in general a problem in stability of nonlinear systems. The present investigation is concerned with the projection of motion on an m-dimensional subspace, taking into account aspects of the hyperstability concept in VSS design. The considered concepts are illustrated with the aid of an example.

  5. The Ages, Masses, Evolution and Kinematics of Mira variable

    E-print Network

    Michael Feast

    2008-12-01

    Evidence on the ages and masses of Mira variables is reviewed. Period increases with increasing initial mass. Miras of logP about 3.0 have initial masses of near 4 solar masses. It is suggestd that the apparent gap in the LMC PL relation at about this period may be due to the onset of hot bottom burning and that this adds about 15 to 20 percent to the stellar energy production. Shorter period HBB stars are probably overtone pulsators. T Lep may be an example of cool bottom processing.

  6. Theories of Variable Mass Particles and Low Energy Nuclear Phenomena

    NASA Astrophysics Data System (ADS)

    Davidson, Mark

    2014-02-01

    Variable particle masses have sometimes been invoked to explain observed anomalies in low energy nuclear reactions (LENR). Such behavior has never been observed directly, and is not considered possible in theoretical nuclear physics. Nevertheless, there are covariant off-mass-shell theories of relativistic particle dynamics, based on works by Fock, Stueckelberg, Feynman, Greenberger, Horwitz, and others. We review some of these and we also consider virtual particles that arise in conventional Feynman diagrams in relativistic field theories. Effective Lagrangian models incorporating variable mass particle theories might be useful in describing anomalous nuclear reactions by combining mass shifts together with resonant tunneling and other effects. A detailed model for resonant fusion in a deuterium molecule with off-shell deuterons and electrons is presented as an example. Experimental means of observing such off-shell behavior directly, if it exists, is proposed and described. Brief explanations for elemental transmutation and formation of micro-craters are also given, and an alternative mechanism for the mass shift in the Widom-Larsen theory is presented. If variable mass theories were to find experimental support from LENR, then they would undoubtedly have important implications for the foundations of quantum mechanics, and practical applications may arise.

  7. Effects of selected design variables on three ramp, external compression inlet performance. [boundary layer control bypasses, and mass flow rate

    NASA Technical Reports Server (NTRS)

    Kamman, J. H.; Hall, C. L.

    1975-01-01

    Two inlet performance tests and one inlet/airframe drag test were conducted in 1969 at the NASA-Ames Research Center. The basic inlet system was two-dimensional, three ramp (overhead), external compression, with variable capture area. The data from these tests were analyzed to show the effects of selected design variables on the performance of this type of inlet system. The inlet design variables investigated include inlet bleed, bypass, operating mass flow ratio, inlet geometry, and variable capture area.

  8. Guide to transverse projections and mass-constraining variables

    SciTech Connect

    Barr, A. J. [Department of Physics, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Khoo, T. J.; Lester, C. G. [Department of Physics, Cavendish Laboratory, JJ Thomson Avenue, Cambridge, CB3 0HE (United Kingdom); Konar, P. [Theoretical Physics Group, Physical Research Laboratory, Ahmedabad, Gujarat - 380 009 (India); Kong, K. [Department of Physics and Astronomy, University of Kansas, Lawrence, KA 66045 (United States); Matchev, K. T.; Park, M. [Department of Physics, University of Florida, Gainesville, Florida 32611 (United States)

    2011-11-01

    This paper seeks to demonstrate that many of the existing mass-measurement variables proposed for hadron colliders (m{sub T}, m{sub eff}, m{sub T2}, missing p-vector{sub T}, h{sub T}, {radical}(s-circumflex){sub min}, etc.) are far more closely related to each other than is widely appreciated, and indeed can all be viewed as a common mass-bound specialized for a variety of purposes. A consequence of this is that one may understand better the strengths and weaknesses of each variable, and the circumstances in which each can be used to best effect. In order to achieve this, we find it necessary first to revisit the seemingly empty and infertile wilderness populated by the subscript 'T' (as in 'pe{sub T}') in order to remind ourselves what this process of transversification actually means. We note that, far from being simple, transversification can mean quite different things to different people. Those readers who manage to battle through the barrage of transverse notation distinguishing 'T' from 'v' or or from 'o', and 'early projection' from 'late projection', will find their efforts rewarded towards the end of the paper with (i) a better understanding of how collider mass variables fit together, (ii) an appreciation of how these variables could be generalized to search for things more complicated than supersymmetry, (iii) will depart with an aversion to thoughtless or naieve use of the so-called 'transverse methods' of any of the popular computer Lorentz-vector libraries, and (iv) will take care in their subsequent papers to be explicit about which of the 61 identified variants of the 'transverse mass' they are employing.

  9. Modal analysis of a nonuniform string with end mass and variable tension

    NASA Technical Reports Server (NTRS)

    Rheinfurth, M. H.; Galaboff, Z. J.

    1983-01-01

    Modal synthesis techniques for dynamic systems containing strings describe the lateral displacements of these strings by properly chosen shape functions. An iterative algorithm is provided to calculate the natural modes of a nonuniform string and variable tension for some typical boundary conditions including one end mass. Numerical examples are given for a string in a constant and a gravity gradient force field.

  10. Shape changing and accelerating solitons in integrable variable mass sine-Gordon model

    E-print Network

    Anjan Kundu

    2007-09-06

    Sine-Gordon model with variable mass (VMSG) appears in many physical systems, ranging from the current through nonuniform Josephson junction to DNA-promoter dynamics. Such models are usually nonintegrable with solutions found numerically or peturbatively. We construct a class of VMSG models, integrable both at classical and quantum level with exact soliton solutions, which can accelerate, change their shape, width and amplitude simulating realistic inhomogeneous systems at certain limits.

  11. Shape Changing and Accelerating Solitons in the Integrable Variable Mass Sine-Gordon Model

    SciTech Connect

    Kundu, Anjan [Theory Group, Saha Institute of Nuclear Physics, Calcutta (India)

    2007-10-12

    The sine-Gordon model with a variable mass (VMSG) appears in many physical systems, ranging from the current through a nonuniform Josephson junction to DNA-promoter dynamics. Such models are usually nonintegrable with solutions found numerically or perturbatively. We construct a class of VMSG models, integrable at both the classical and the quantum levels with exact soliton solutions, which can accelerate and change their shape, width, and amplitude simulating realistic inhomogeneous systems at certain limits.

  12. Variable speed wind turbine control system

    SciTech Connect

    Conley, E.

    1981-08-01

    Variable speed wind turbine operation is discussed for potential increased energy production if the turbine rotor is controlled to operate at constant blade tip speed to wind speed ratio. Two variable speed control systems are compared to a constant speed control system during field tests of a 5m Darrieus type wind turbine generator. 6 refs.

  13. Variable structure systems with sliding modes

    Microsoft Academic Search

    VADIM I. UTKIN

    1977-01-01

    Variable structure systems consist of a set of continuous subsystems together with suitable switching logic. Advantageous properties result from changing structures according to this switching logic. Design and analysis for this class of systems are surveyed in this paper.

  14. Short time-scale AGN X-ray variability with EXOSAT: black hole mass and normalized variability amplitude

    NASA Astrophysics Data System (ADS)

    McHardy, I. M.

    2013-03-01

    The old EXOSAT medium energy measurements of high-frequency (HF) active galactic nuclei (AGN) power spectral normalization are re-examined in the light of accurate black hole mass determinations which were not available when these data were first published by Green et al. It is found that the normalized variability amplitude (NVA), measured directly from the power spectrum, is proportional to M?, where ? ˜ -0.54 ± 0.08. As NVA is the square root of the power, these observations show that the normalization of the HF power spectrum for this sample of AGN varies very close to inversely with black hole mass. Almost the same value of ? is obtained whether the quasar 3C 273 is included in the sample or not, suggesting that the same process that drives X-ray variability in Seyfert galaxies applies also to 3C 273. These observations support the work of Gierli?ski et al. who show that an almost exactly linear anticorrelation is required if the normalizations of the HF power spectra of AGN and X-ray binary systems are to scale similarly. These observations are also consistent with a number of studies showing that the short time-scale variance of AGN X-ray light curves varies approximately inversely with mass.

  15. Model atmospheres with periodic shocks. [pulsations and mass loss in variable stars

    NASA Technical Reports Server (NTRS)

    Bowen, G. H.

    1989-01-01

    The pulsation of a long-period variable star generates shock waves which dramatically affect the structure of the star's atmosphere and produce conditions that lead to rapid mass loss. Numerical modeling of atmospheres with periodic shocks is being pursued to study the processes involved and the evolutionary consequences for the stars. It is characteristic of these complex dynamical systems that most effects result from the interaction of various time-dependent processes.

  16. Mass Market Demand Response and Variable Generation Integration Issues: A Scoping Study

    SciTech Connect

    Cappers, Peter; Mills, Andrew; Goldman, Charles; Wiser, Ryan; Eto, Joseph H.

    2011-09-10

    This scoping study focuses on the policy issues inherent in the claims made by some Smart Grid proponents that the demand response potential of mass market customers which is enabled by widespread implementation of Advanced Metering Infrastructure (AMI) through the Smart Grid could be the “silver bullet” for mitigating variable generation integration issues. In terms of approach, we will: identify key issues associated with integrating large amounts of variable generation into the bulk power system; identify demand response opportunities made more readily available to mass market customers through widespread deployment of AMI systems and how they can affect the bulk power system; assess the extent to which these mass market Demand Response (DR) opportunities can mitigate Variable Generation (VG) integration issues in the near-term and what electricity market structures and regulatory practices could be changed to further expand the ability for DR to mitigate VG integration issues over the long term; and provide a qualitative comparison of DR and other approaches to mitigate VG integration issues.

  17. Mass flow fuel injection control system

    SciTech Connect

    Staerzl, R.E.

    1988-06-14

    A mass flow fuel injection control system is described for an internal combustion engine having air intake means supplying combustion air to the engine, and fuel injector means supplying fuel to the engine. The control system consists of: air flow velocity sensing means comprising venturi means in the air intake means producing a pressure drop, and means measuring the differential pressure P/sub D/ between the absolute pressure outside of the venturi means and the reduced pressured in the venturi means, and means calculating the air air flow velocity as a function of P/sub D/; means sensing the mass of the combustion air comprising means measuring the absolute air pressure P/sub A/ outside of the venturi means and temperature sensor means measuring air temperature T, and the calculating air mass as a function of P/sub A/ and T; means responsive to the air flow velocity sensor means and the air mass sensor means and controlling the fuel injector means; tachometer means for measuring engine speed S, and variable resistance attenuator means responsive to the tachometer means and connected to the air flow velocity sensing means and changing resistance with increasing engine speed such that air flow velocity sensing means divides P/sub D/ by a given power of S.

  18. Automated mass spectrometer analysis system

    NASA Technical Reports Server (NTRS)

    Kuppermann, Aron (Inventor); Dreyer, William J. (Inventor); Giffin, Charles E. (Inventor); Boettger, Heinz G. (Inventor)

    1982-01-01

    An automated mass spectrometer analysis system is disclosed, in which samples are automatically processed in a sample processor and converted into volatilizable samples, or their characteristic volatilizable derivatives. Each volatilizable sample is sequentially volatilized and analyzed in a double focusing mass spectrometer, whose output is in the form of separate ion beams all of which are simultaneously focused in a focal plane. Each ion beam is indicative of a different sample component or different fragments of one or more sample components and the beam intensity is related to the relative abundance of the sample component. The system includes an electro-optical ion detector which automatically and simultaneously converts the ion beams, first into electron beams which in turn produce a related image which is transferred to the target of a vilicon unit. The latter converts the images into electrical signals which are supplied to a data processor, whose output is a list of the components of the analyzed sample and their abundances. The system is under the control of a master control unit, which in addition to monitoring and controlling various power sources, controls the automatic operation of the system under expected and some unexpected conditions and further protects various critical parts of the system from damage due to particularly abnormal conditions.

  19. Causes of temporal variability of lead in domestic plumbing systems.

    PubMed

    Schock, M R

    1990-07-01

    Sources of lead in drinking water are primarily lead pipe, lead/tin solder, and brass fixture materials.Lead levels in the water depend upon many solubility factors, such as pH, concentrations of substances such as inorganic carbonate, orthophosphate, chlorine, and silicate, the temperature, the nature of the pipe surface, etc. Physical factors, time, and chemical mass transfer are significant in governing lead levels in nonequilibrium systems. The diameter and length of lead pipe is extremely important, as well as the age and chemical history of the solder and brass fixtures. Analytical variability is not particularly significant relative to between-site and within-site variability. Knowledge of temporal variability at each site is necessary to define a statistically valid monitoring program. An analysis of published data covering repetitive measurements at a given site show that the variability of lead concentration at each site tends to be characterized by the frequent occurrence of 'spikes'. Variability expressed as approximate relative standard deviations tends to be of about 50 to 75% in untreated water, regardless of the mean lead concentration. The distributions are frequently nonnormal for small numbers of samples. Monitoring programs must incorporate controls for the causes of the within-site and between-site variability into their sampling design. The determination of necessary sampling frequency, sample number, and sample volume must be made with consideration of the system variability, or the results will be unrepresentative and irreproducible. PMID:24243429

  20. Assessment of reservoir system variable forecasts

    NASA Astrophysics Data System (ADS)

    Kistenmacher, Martin; Georgakakos, Aris P.

    2015-05-01

    Forecast ensembles are a convenient means to model water resources uncertainties and to inform planning and management processes. For multipurpose reservoir systems, forecast types include (i) forecasts of upcoming inflows and (ii) forecasts of system variables and outputs such as reservoir levels, releases, flood damage risks, hydropower production, water supply withdrawals, water quality conditions, navigation opportunities, and environmental flows, among others. Forecasts of system variables and outputs are conditional on forecasted inflows as well as on specific management policies and can provide useful information for decision-making processes. Unlike inflow forecasts (in ensemble or other forms), which have been the subject of many previous studies, reservoir system variable and output forecasts are not formally assessed in water resources management theory or practice. This article addresses this gap and develops methods to rectify potential reservoir system forecast inconsistencies and improve the quality of management-relevant information provided to stakeholders and managers. The overarching conclusion is that system variable and output forecast consistency is critical for robust reservoir management and needs to be routinely assessed for any management model used to inform planning and management processes. The above are demonstrated through an application from the Sacramento-American-San Joaquin reservoir system in northern California.

  1. Linear change of variable in normal systems.

    NASA Technical Reports Server (NTRS)

    Mulholland, J. D.

    1973-01-01

    Linear transformations of variable in differential correction processes cannot always be accomplished in the equations of condition, yet may be desirable to reduce high correlations. The means by which this may be accomplished in the system of normal equations is derived and the process reduced to a very simple computational algorithm.

  2. Quantifying decoherence in continuous variable systems

    Microsoft Academic Search

    A Serafini; M G A Paris; F. Illuminati; S. De Siena

    2005-01-01

    We present a detailed report on the decoherence of quantum states of continuous variable systems under the action of a quantum optical master equation resulting from the interaction with general Gaussian uncorrelated environments. The rate of decoherence is quantified by relating it to the decay rates of various, complementary measures of the quantum nature of a state, such as the

  3. Control system for a infinitely variable transmission

    Microsoft Academic Search

    Morimoto

    1988-01-01

    This patent describes a control system for an infinitely variable transmission for transmitting power of an internal combustion engine to driving wheels of a motor vehicle, the transmission having a drive pulley including a hydraulically shiftable first disc and a first hydraulic cylinder for shifting the first disc, a driven pulley including a hydraulically shiftable second disc and a second

  4. Control system for an infinitely variable transmission

    Microsoft Academic Search

    Miyawaki

    1987-01-01

    This patent describes a control system for an infinitely variable transmission for transmitting the power of an internal combustion engine mounted on a vehicle. The transmission comprises: a primary pulley operatively connected to a crankshaft of the engine having a hydraulically shiftable disc and a first hydraulic cylinder for shifting the disc; a secondary pulley operatively connected to an output

  5. The turbulent mean-flow, Reynolds-stress, and heat flux equations in mass-averaged dependent variables

    NASA Technical Reports Server (NTRS)

    Rubesin, M. W.; Rose, W. C.

    1973-01-01

    The time-dependent, turbulent mean-flow, Reynolds stress, and heat flux equations in mass-averaged dependent variables are presented. These equations are given in conservative form for both generalized orthogonal and axisymmetric coordinates. For the case of small viscosity and thermal conductivity fluctuations, these equations are considerably simpler than the general Reynolds system of dependent variables for a compressible fluid and permit a more direct extension of low speed turbulence modeling to computer codes describing high speed turbulence fields.

  6. Disentanglement in bipartite continuous-variable systems

    SciTech Connect

    Barbosa, F. A. S.; Coelho, A. S.; Nussenzveig, P.; Martinelli, M. [Instituto de Fisica, Universidade de Sao Paulo, P.O. Box 66318, 05315-970 Sao Paulo (Brazil); Faria, A. J. de [Instituto de Cie circumflex ncia e Tecnologia, Universidade Federal de Alfenas, 37715-400 Pocos de Caldas, MG (Brazil); Cassemiro, K. N. [Instituto de Fisica, Universidade de Sao Paulo, P.O. Box 66318, 05315-970 Sao Paulo (Brazil); Max Planck Institute for the Science of Light, DE-91058 Erlangen (Germany); Villar, A. S. [Instituto de Fisica, Universidade de Sao Paulo, P.O. Box 66318, 05315-970 Sao Paulo (Brazil); Max Planck Institute for the Science of Light, DE-91058 Erlangen (Germany); Lehrstuhl fuer Optik, Universitaet Erlangen-Nuernberg, DE-91058 Erlangen (Germany)

    2011-11-15

    Entanglement in bipartite continuous-variable systems is investigated in the presence of partial losses such as those introduced by a realistic quantum communication channel, e.g., by propagation in an optical fiber. We find that entanglement can vanish completely for partial losses, in a situation reminiscent of so-called entanglement sudden death. Even states with extreme squeezing may become separable after propagation in lossy channels. Having in mind the potential applications of such entangled light beams to optical communications, we investigate the conditions under which entanglement can survive for all partial losses. Different loss scenarios are examined, and we derive criteria to test the robustness of entangled states. These criteria are necessary and sufficient for Gaussian states. Our study provides a framework to investigate the robustness of continuous-variable entanglement in more complex multipartite systems.

  7. Hybrid-Entanglement in Continuous Variable Systems

    Microsoft Academic Search

    C. Gabriel; A. Aiello; W. Zhong; T. G. Euser; N. Y. Joly; P. Banzer; M. Förtsch; D. Elser; U. L. Andersen; Ch. Marquardt; P. St. J. Russell; G. Leuchs

    2010-01-01

    Entanglement is one of the most fascinating features arising from quantum-mechanics and of great importance for quantum information science. Of particular interest are so-called hybrid-entangled states which have the intriguing property that they contain entanglement between different degrees of freedom (DOFs). However, most of the current continuous variable systems only exploit one DOF and therefore do not involve such highly

  8. Mobile Variable Depth Sampling System Design Study

    SciTech Connect

    BOGER, R.M.

    2000-08-25

    A design study is presented for a mobile, variable depth sampling system (MVDSS) that will support the treatment and immobilization of Hanford LAW and HLW. The sampler can be deployed in a 4-inch tank riser and has a design that is based on requirements identified in the Level 2 Specification (latest revision). The waste feed sequence for the MVDSS is based on Phase 1, Case 3S6 waste feed sequence. Technical information is also presented that supports the design study.

  9. Energy efficient ECS powered by a variable voltage/variable frequency power system

    SciTech Connect

    Cronin, M. J.

    1985-10-15

    The invention is an ECS system designed to utilize an induction motor and a cabin compressor for providing pressurized air that serves as a source of energy for heating, cooling, pressurizing and other air needs of modern aircraft. An aircraft engine driven generator, preferably a permanent-magnet generator (of the samarium-cobalt, SmCo, type), furnishes variable-voltage/variable frequency, VV/VF, power to the motor. The electric motor itself in the preferred embodiment is a highly reliable squirrel-cage induction motor powered directly from the VV/VF supply, with the result that its speed is proportional to the generator frequency, which in turn is dependent on the aircraft engine speed. The main cabin compressor and a secondary (auxiliary) supercharging compressor are both mounted on the motor shaft. The motor-compressor configuration is further characterized in that the ac motor has pole-changing winding (typically two), which permits two speed operation, while the cabin compressor is provided with inlet guide vanes. The interactive combination of these two features makes it possible to furnish the requisite air mass flow and pressurization levels over the conditions of variable air density and variable atmospheric pressure, as the airplane operates throughout its flight envelope.

  10. Energy efficient ECS powered by a variable voltage/variable frequency power system

    SciTech Connect

    Cronin, M.J.

    1984-07-31

    The invention is an ECS system designed to utilize an induction motor and a cabin compressor for providing pressurized air that serves as a source of energy for heating, cooling, pressurizing and other air needs of modern aircraft. An aircraft engine driven generator, preferably a permanent-magnet generator (of the samarium-cobalt, SmCo, type), furnishes variable-voltage/variable frequency, VV/VF, power to the motor. The electric motor itself in the preferred embodiment is a highly reliable squirrel-cage induction motor powered directly from the VV/VF supply, with the result that its speed is proportional to the generator frequency, which in turn is dependent on the aircraft engine speed. The main cabin compressor and a secondary (auxiliary) supercharging compressor are both mounted on the motor shaft. The motor-compressor configuration is further characterized in that the ac motor has pole-changing winding (typically two), which permits two speed operation, while the cabin compressor is provided with inlet guide vanes. The interactive combination of these two features makes it possible to furnish the requisite air mass flow and pressurization levels over the conditions of variable air density and variable atmospheric pressure, as the airplane operates throughout its flight envelope.

  11. Salinity Variability in the California Current System

    NASA Astrophysics Data System (ADS)

    Kilpatrick, T.; Schneider, N.; di Lorenzo, E.

    2008-12-01

    A regional model is used to study the interannual to decadal salinity variability in the California Current (CC) system, using multiple simulations of 1950-2005. The model reproduces the mean structure, red variance spectrum, and the spiciness in the CalCoFI observations. However, the model standard deviation is too high by roughly 40%, and has too high positive skewness. The model also fails to reproduce the phase of the salinity time evolution; however the salinity shows variability between different realizations of the model, suggesting intrinsic variability as a contributing cause. To study the generation mechanism for low-frequency anomalies, we first try to remove the effect of isopycnal heave (associated with eddies) by using a density surface. Anomalies on the 1025.6 density surface at 36N have a decorrelation time scale of 23 months. Their generation is consistent with anomalous advection upstream in the CC, such that anomalously salty water in the CC is associated with a southward displacement of the North Pacific Current and weakened inflow from the north. Strong lateral gradients characterize the one-month averages of CC salinity, temperature and density. In the region southwest of the mean CC path, the salinity gradients are compensated and thus lack a strong dynamical signature. We propose that these dynamically passive salinity gradients are displaced by eddies and lead to the intrinsic variability observed there. At the region closer to Cape Mendocino, salinity gradients are associated with a density front and may be an active player in the dynamics.

  12. Variable/Multispeed Rotorcraft Drive System Concepts

    NASA Technical Reports Server (NTRS)

    Stevens, Mark A.; Handschuh, Robert F.; Lewicki, David G.

    2009-01-01

    Several recent studies for advanced rotorcraft have identified the need for variable, or multispeed-capable rotors. A speed change of up to 50 percent has been proposed for future rotorcraft to improve vehicle performance. Varying rotor speed during flight not only requires a rotor capable of performing effectively over the extended operation speed and load range, but also requires an advanced propulsion system to provide the required speed changes. A study has been completed, which investigated possible drive system arrangements to accommodate up to the 50 percent speed change. These concepts are presented. The most promising configurations are identified and will be developed for future validation testing.

  13. THE ENIGMATIC YOUNG, LOW-MASS VARIABLE TWA 30

    E-print Network

    Looper, Dagny L.

    TWA 30 is a remarkable young (7 ± 3 Myr), low-mass (0.12 ± 0.04 M [subscript ?]), late-type star (M5 ± 1) residing 42 ± 2 pc away from the Sun in the TW Hydrae Association (TWA). It shows strong outflow spectral signatures ...

  14. Atmospheric Structure, Shocks and Mass Loss in RV Tauri Variables

    Microsoft Academic Search

    Edward W. Brugel

    1987-01-01

    RV Tauri variables are a distinct and unique class of pulsationally unstable stars. Their behavior is characterized by alternating deep and shallow minima, and they tend to show spectral variations indicative of metal poor supergiants (II-Ib, Ia) of type F, G, and K. Periods are typically 30-150^d, with the majority 50-100^d. The period-luminosity diagram indicates that the RV Tau's fall

  15. Mass-losing Semiregular Variable Stars in Baade's Windows

    Microsoft Academic Search

    C. Alard; J. A. D. L. Blommaert; C. Cesarsky; N. Epchtein; M. Felli; P. Fouque; S. Ganesh; R. Genzel; G. Gilmore; I. S. Glass; H. Habing; A. Omont; M. Perault; S. Price; A. Robin; M. Schultheis; G. Simon; J. Th. van Loon; C. Alcock; R. A. Allsman; D. R. Alves; T. S. Axelrod; A. C. Becker; D. P. Bennett; K. H. Cook; A. J. Drake; K. C. Freeman; M. Geha; K. Griest; M. J. Lehner; D. Minniti; C. Nelson; B. A. Peterson; P. Popowski; M. R. Pratt; P. J. Quinn; W. Sutherland; A. B. Tomaney; T. Vandehei; D. L. Welch

    2001-01-01

    By cross-correlating the results of two recent large-scale surveys, the general properties of a well-defined sample of semiregular variable stars have been determined. ISOGAL mid-infrared photometry (7 and 15 mum) and MACHO V and R light curves are assembled for approximately 300 stars in the Baade's windows of low extinction toward the Galactic bulge. These stars are mainly giants of

  16. Probing the spatial and temporal variability of Enceladus mass-loading from ion cyclotron waves

    NASA Astrophysics Data System (ADS)

    Wei, H.; Russell, C. T.; Powell, R. L.; Cowee, M.; Leisner, J. S.; Jia, Y.; Dougherty, M. K.

    2013-12-01

    Enceladus plays a critical role in the Saturnian system by loading a significant amount of neutrals, ions and dust into the inner magnetosphere. Enceladus is also considered as the ultimate source for the dusty E-ring and the extended neutral cloud from 3.5 to 6.5 Saturn radii. When the freshly-added neutrals are ionized and accelerated by the electric and magnetic fields, left-handed electromagnetic waves, called ion cyclotron waves (ICW), grow from the free energy of the highly anisotropic distribution of these ions. The ICWs have been widely used to probe the rate of mass loading in different plasma environments in the solar system, because the wave power is proportional to the density and energy of the pickup ions. At Enceladus, ICWs are detected by Cassini not only near the moon but throughout the extended neutral cloud in all local times. However, the wave power is largely enhanced near the moon's longitude rather than far away from it. This indicates that on top of the relatively azimuthally-symmetric mass-loading source of the neutral cloud, there is a much denser cloud of neutrals centered on the moon and rotating with it. The latter source is the instantaneous mass-loading from plume of Enceladus, and it leads to asymmetry and dynamics in the magnetosphere. We investigate all available Cassini Enceladus flyby data to obtain a 3D spatial profile of the ICW power near the moon. By comparing with waves at longitudes far away from the moon, we investigate how significant is the plume mass-loading with respect to the neutral cloud mass-loading. We also compare the waves along several groups of identical trajectories to examine the temporal variability of the plume.

  17. Hybrid-Entanglement in Continuous Variable Systems

    E-print Network

    C. Gabriel; A. Aiello; W. Zhong; T. G. Euser; N. Y. Joly; P. Banzer; M. Förtsch; D. Elser; U. L. Andersen; Ch. Marquardt; P. St. J. Russell; G. Leuchs

    2010-07-08

    Entanglement is one of the most fascinating features arising from quantum-mechanics and of great importance for quantum information science. Of particular interest are so-called hybrid-entangled states which have the intriguing property that they contain entanglement between different degrees of freedom (DOFs). However, most of the current continuous variable systems only exploit one DOF and therefore do not involve such highly complex states. We break this barrier and demonstrate that one can exploit squeezed cylindrically polarized optical modes to generate continuous variable states exhibiting entanglement between the spatial and polarization DOF. We show an experimental realization of these novel kind of states by quantum squeezing an azimuthally polarized mode with the help of a specially tailored photonic crystal fiber.

  18. Hybrid-Entanglement in Continuous Variable Systems

    E-print Network

    Gabriel, C; Zhong, W; Euser, T G; Joly, N Y; Banzer, P; Förtsch, M; Elser, D; Andersen, U L; Marquardt, Ch; Russell, P St J; Leuchs, G

    2010-01-01

    Entanglement is one of the most fascinating features arising from quantum-mechanics and of great importance for quantum information science. Of particular interest are so-called hybrid-entangled states which have the intriguing property that they contain entanglement between different degrees of freedom (DOFs). However, most of the current continuous variable systems only exploit one DOF and therefore do not involve such highly complex states. We break this barrier and demonstrate that one can exploit squeezed cylindrically polarized optical modes to generate continuous variable states exhibiting entanglement between the spatial and polarization DOF. We show an experimental realization of these novel kind of states by quantum squeezing an azimuthally polarized mode with the help of a specially tailored photonic crystal fiber.

  19. Apparent mass of the human body in the vertical direction: Inter-subject variability

    Microsoft Academic Search

    Martin G. R. Toward; Michael J. Griffin

    2011-01-01

    The biodynamic responses of the seated human body to whole-body vibration vary considerably between people, but the reasons for the variability are not well understood. This study was designed to determine how the physical characteristics of people affect their apparent mass and whether inter-subject variability is influenced by the magnitude of vibration and the support of a seat backrest. The

  20. Dual output variable pitch turbofan actuation system

    NASA Technical Reports Server (NTRS)

    Griswold, R. H., Jr.; Broman, C. L. (inventors)

    1976-01-01

    An improved actuating mechanism was provided for a gas turbine engine incorporating fan blades of the variable pitch variety, the actuator adapted to rotate the individual fan blades within apertures in an associated fan disc. The actuator included means such as a pair of synchronizing ring gears, one on each side of the blade shanks, and adapted to engage pinions disposed thereon. Means were provided to impart rotation to the ring gears in opposite directions to effect rotation of the blade shanks in response to a predetermined input signal. In the event of system failure, a run-away actuator was prevented by an improved braking device which arrests the mechanism.

  1. AN EVALUATION OF THE VARIABILITY OF AIR MASS CHARACTER BETWEEN URBAN AND RURAL AREAS

    E-print Network

    Sheridan, Scott

    AN EVALUATION OF THE VARIABILITY OF AIR MASS CHARACTER BETWEEN URBAN AND RURAL AREAS Scott C between urban and rural sites. Data are segregated by air mass and by season. Overall, the three "dry" air of the most intense urban/rural differentiations, with overnight temperatures typically 3° C or more above

  2. Greenland Ice Sheet Surface Mass Balance Variability (19882004) from Calibrated Polar MM5 Output*

    E-print Network

    Howat, Ian M.

    of Greenland ice sheet surface mass balance (SMB) change over a 17-yr period characterized by warming (1988Greenland Ice Sheet Surface Mass Balance Variability (1988­2004) from Calibrated Polar MM5 Output in Environmental Sciences, University of Colorado, Boulder, Colorado (Manuscript received 9 May 2005, in final form

  3. Moving mass trim control system design

    SciTech Connect

    Byrne, R.H.; Robinett, R.D.; Sturgis, B.R.

    1996-03-01

    This paper describes the design of a moving mass trim control system for maneuvering axisymmetric reentry vehicles. The moving mass trim controller is composed of three equal masses that are independently positioned in order to deliver a desired center of mass position. For a slowly spinning reentry vehicle, the mass offset creates a trim angle-of-attack to generate modest flight path corrections. The control system must maintain the desired position of each mass in the face of large disturbances. A novel algorithm for determining the desired mass positions is developed in conjunction with a preliminary controller design. The controller design is based on classical frequency domain techniques where a bound on the disturbance magnitude is used to formulate the disturbance rejection problem. Simulation results for the controller are presented for a typical reentry vehicle.

  4. Variable Speed Drive Volumetric Tracking (VSDVT) for Airflow Control in Variable Air Volume (VAV) Systems 

    E-print Network

    Liu, M.

    2002-01-01

    An airflow control method has been developed for variable air volume (VAV) systems. This airflow control method is named VSD volumetric tracking (VSDVT) since both the supply and return airflows are determined using signals of the variable speed...

  5. Assessment of the structure and variability of Weddell Sea water masses in distinct ocean reanalysis products

    NASA Astrophysics Data System (ADS)

    Dotto, T. S.; Kerr, R.; Mata, M. M.; Azaneu, M.; Wainer, I.; Fahrbach, E.; Rohardt, G.

    2014-06-01

    We assessed and evaluated the performance of five ocean reanalysis products in reproducing essential hydrographic properties and their associated temporal variability for the Weddell Sea, Antarctica. The products used in this assessment were ECMWF ORAS4 (European Centre for Medium-Range Weather Forecasts Ocean Reanalysis System 4), CFSR (Climate Forecast System Reanalysis), MyOcean UR025.4 (University of Reading), ECCO2 (Estimating the Circulation and Climate of the Ocean, Phase II) and SODA (Simple Ocean Data Assimilation). The present study focuses on the Weddell Sea deep layer, which is composed of the following three main water masses: Warm Deep Water (WDW), Weddell Sea Deep Water (WSDW) and Weddell Sea Bottom Water (WSBW). The MyOcean UR025.4 product provided the most accurate representation of the structure and thermohaline properties of the Weddell Sea water masses when compared with observations. All the ocean reanalysis products analyzed exhibited limited capabilities in representing the surface water masses in the Weddell Sea. The CFSR and ECCO2 products were not able to represent deep water masses with a neutral density ? 28.40 kg m-3, which was considered the WSBW's upper limit throughout the simulation period. The expected WDW warming was only reproduced by the SODA product, whereas the ECCO2 product was able to represent the trends in the WSDW's hydrographic properties. All the assessed ocean reanalyses were able to represent the decrease in the WSBW's density, except the SODA product in the inner Weddell Sea. Improvements in parameterization may have as much impact on the reanalyses assessed as improvements in horizontal resolution primarily because the Southern Ocean lacks in situ data, and the data that are currently available are summer-biased. The choice of the reanalysis product should be made carefully, taking into account the performance, the parameters of interest, and the type of physical processes to be evaluated.

  6. Air Pressure Controlled Mass Measurement System

    NASA Astrophysics Data System (ADS)

    Zhong, Ruilin; Wang, Jian; Cai, Changqing; Yao, Hong; Ding, Jin'an; Zhang, Yue; Wang, Xiaolei

    Mass measurement is influenced by air pressure, temperature, humidity and other facts. In order to reduce the influence, mass laboratory of National Institute of Metrology, China has developed an air pressure controlled mass measurement system. In this system, an automatic mass comparator is installed in an airtight chamber. The Chamber is equipped with a pressure controller and associate valves, thus the air pressure can be changed and stabilized to the pre-set value, the preferred pressure range is from 200 hPa to 1100 hPa. In order to keep the environment inside the chamber stable, the display and control part of the mass comparator are moved outside the chamber, and connected to the mass comparator by feed-throughs. Also a lifting device is designed for this system which can easily lift up the upper part of the chamber, thus weights can be easily put inside the mass comparator. The whole system is put on a marble platform, and the temperature and humidity of the laboratory is very stable. The temperature, humidity, and carbon dioxide content inside the chamber are measured in real time and can be used to get air density. Mass measurement cycle from 1100 hPa to 200 hPa and back to 1100 hPa shows the effective of the system.

  7. Mass balance study of gravitational mass movements in proglacial systems

    NASA Astrophysics Data System (ADS)

    Rohn, Joachim; Vehling, Lucas; Moser, Michael

    2013-04-01

    In the framework of the DFG joint research project PROSA (high resoluted measurements of morphodynamics in rapidly changing PROglacial Systems of the Alps), mass movements are investigated geotechnically and process rates will be determined. As result, the actual mass balance for gravitational mass movements will be investigated exemplarily in an alpine glacier foreland in this PROSA sub-project. Alpine glacier forelands are defined as the area between the edge of the glacier and the moraines of the latest maximum in 1850. Since then, the region has become ice free due to the retreat of the glaciers. Because of this recent development, the glacier foreland differs considerably from the surrounding landscape and exhibits a rapid morphodynamic development. Mass movements like landslides and rock falls contribute a remarkable portion to total sediment transport in this area. As study area the region between Gepatschferner and Gepatsch backwater was choosen. The study area encompasses 62,5 km², lies at altitudes between 1759 and 3539 m a.s.l. and around 30 % are covered by glacier. Basic prerequisite is the geotechnical inventory-taking including the production of a geotechnical map. All mass balance studies for gravitational mass movements will base on this data collection. Short term behaviour during extreme meteorological events will be investigated as well, as the long term behaviour of the alpine slopes. The results of repeated high-resolution airborne laser scanning will contribute to a complete area-wide detection of surface changes. Detailed periodical terrestrial laser scanning of steep rock walls and their scree cones, as well as of slopes with soft rock will complete the data set. Spot tests with nets collecting the rock fall material, constructed on elected scree cones, allow the control and verification of the collected data. Mass movements in hard rock apart from rock fall processes, like rock creep, rock sliding and sagging will be monitored additionally with tape dilatometer measurements. High resolution displacement- and temperature sensors installed in different depth of the rock and combined with electronic data collectors accomplish the data acquisition system. All these investigations will allow us to determine the actual mass balance of gravitational mass movements in an alpine glacier foreland. In a world with changing climate, this will provide the base for the study of future scenarios.

  8. PERIODIC VARIABILITY OF LOW-MASS STARS IN SLOAN DIGITAL SKY SURVEY STRIPE 82

    SciTech Connect

    Becker, A. C.; Hawley, S. L.; Ivezic, Z.; Kowalski, A. F.; Sesar, B. [Astronomy Department, University of Washington, Seattle, WA 98195 (United States); Bochanski, J. J. [Astronomy and Astrophysics Department, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); West, A. A. [Department of Astronomy, Boston University, 725 Commonwealth Avenue, Boston, MA 02215 (United States)

    2011-04-10

    We present a catalog of periodic stellar variability in the 'Stripe 82' region of the Sloan Digital Sky Survey. After aggregating and re-calibrating catalog-level data from the survey, we ran a period-finding algorithm (Supersmoother) on all point-source light curves. We used color selection to identify systems that are likely to contain low-mass stars, in particular M dwarfs and white dwarfs. In total, we found 207 candidates, the vast majority of which appear to be in eclipsing binary systems. The catalog described in this paper includes 42 candidate M dwarf/white dwarf pairs, four white dwarf pairs, 59 systems whose colors indicate they are composed of two M dwarfs and whose light-curve shapes suggest they are in detached eclipsing binaries, and 28 M dwarf systems whose light-curve shapes suggest they are in contact binaries. We find no detached systems with periods longer than 3 days, thus the majority of our sources are likely to have experienced orbital spin-up and enhanced magnetic activity. Indeed, 26 of 27 M dwarf systems that we have spectra for show signs of chromospheric magnetic activity, far higher than the 24% seen in field stars of the same spectral type. We also find binaries composed of stars that bracket the expected boundary between partially and fully convective interiors, which will allow the measurement of the stellar mass-radius relationship across this transition. The majority of our contact systems have short orbital periods, with small variance (0.02 days) in the sample near the observed cutoff of 0.22 days. The accumulation of these stars at short orbital period suggests that the process of angular momentum loss, leading to period evolution, becomes less efficient at short periods. These short-period systems are in a novel regime for studying the effects of orbital spin-up and enhanced magnetic activity, which are thought to be the source of discrepancies between mass-radius predictions and measurements of these properties in eclipsing binaries.

  9. Seasonal and inter-annual mass variability in Antarctica from GRACE

    NASA Astrophysics Data System (ADS)

    Pangaluru, K.; Velicogna, I.; Swenson, S. C.; van den Broeke, M. R.; Bromwich, D. H.; Monaghan, A. J.

    2011-12-01

    The seasonal and inter-annual variability in Antarctic surface mass balance represent important components of the temporal variability in total ice sheet mass balance. At present, large uncertainties remain in our knowledge of those temporal components, spatial distribution and long-term trend. GRACE measurements of time variable gravity represent one of the only ways to directly measure the monthly ice sheet mass changes and - if accurate enough - provide important insights to constrain the seasonal and inter-annual variability in surface mass balance, which in turn is essential to evaluate global and regional atmospheric climate model outputs. In Antarctica, errors in the atmospheric mass correction applied to the GRACE data are the dominant uncertainties on the retrieval of seasonal and inter-annual mass changes. We estimate the error in monthly GRACE correction for the atmospheric mass distribution by comparing surface pressure fields from available GPS-RO (e.g. CHAMP, SAC-C, and COSMIC) and ECMWF pressure fields. We evaluate the results using available surface pressure measurements from Automatic Weather Stations (AWS). We compare the spatial pattern in our atmospheric error estimates with different estimates of surface mass balance (SMB) derived from regional atmospheric climate model outputs, from the continental scale down to the regional scale, to determine if those errors are associated to particular regional conditions and climatic regimes. We show that when averaged over the entire ice sheet or East or West Antarctica, the accuracy of the GRACE data is sufficient to constrain seasonal and inter-annual changes in surface mass balance. But when moving to smaller scales, e.g. at the scale of a drainage basin, we identify regions where the uncertainty in atmospheric mass correction is large enough to impair the scientific interpretability of the GRACE results. In those areas, we generate preliminary corrections to the GRACE data and evaluate the results.

  10. MASS: An automated accountability system

    SciTech Connect

    Erkkila, B.H.; Kelso, F.

    1994-08-01

    All Department of Energy contractors who manage accountable quantities of nuclear materials are required to implement an accountability system that tracks, and records the activities associated with those materials. At Los Alamos, the automated accountability system allows data entry on computer terminals and data base updating as soon as the entry is made. It is also able to generate all required reports in a timely Fashion. Over the last several years, the hardware and software have been upgraded to provide the users with all the capability needed to manage a large variety of operations with a wide variety of nuclear materials. Enhancements to the system are implemented as the needs of the users are identified. The system has grown with the expanded needs of the user; and has survived several years of changing operations and activity. The user community served by this system includes processing, materials control and accountability, and nuclear material management personnel. In addition to serving the local users, the accountability system supports the national data base (NMMSS). This paper contains a discussion of several details of the system design and operation. After several years of successful operation, this system provides an operating example of how computer systems can be used to manage a very dynamic data management problem.

  11. Variable mass theories in relativistic quantum mechanics as an explanation for anomalous low energy nuclear phenomena

    NASA Astrophysics Data System (ADS)

    Davidson, Mark

    2015-05-01

    A recent theoretical explanation for observed anomalous low energy nuclear phenomena which have puzzled physicists for many years is expanded on. Based on covariant relativistic quantum mechanics and historical time wave equations, it explains a large number of observed anomalous effects by supposing that nuclear masses can vary in “nuclear active environments” in condensed matter settings. The modified quantum wave equation originally introduced by Fock and Stueckelberg in the 1930s with significant enhancements up to the present by Horwitz and others prove that variable masses are compatible with the principles of both quantum mechanics and relativity. They can explain all of these effects by modifying the kinematic constraints of the reaction, enhancing electron screening and quantum tunneling rates, and allowing for resonant tunneling. Some previous results are recounted, and experimental evidence based on variable radioactive decay rates and other evidence for variable masses is presented which adds some new potential support for this theory.

  12. Mass Storage Performance Information System

    NASA Technical Reports Server (NTRS)

    Scheuermann, Peter

    2000-01-01

    The purpose of this task is to develop a data warehouse to enable system administrators and their managers to gather information by querying the data logs of the MDSDS. Currently detailed logs capture the activity of the MDSDS internal to the different systems. The elements to be included in the data warehouse are requirements analysis, data cleansing, database design, database population, hardware/software acquisition, data transformation, query and report generation, and data mining.

  13. Measuring the top quark mass with the m{sub T2} variable

    SciTech Connect

    Cho, Won Sang; Choi, Kiwoon; Kim, Yeong Gyun; Park, Chan Beom [Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of)

    2008-08-01

    We investigate the possibility of measuring the top quark mass using the collider variable m{sub T2} at the CERN LHC experiment. Monte Carlo studies of m{sub T2} are performed with the events corresponding to the dilepton decays of tt produced at the LHC with 10 fb{sup -1} integrated luminosity. Our analysis suggests that the top quark mass can be determined by the m{sub T2} variable with a reasonable accuracy, though the precision will be determined by systematic errors for which a more complete analysis would need to be performed.

  14. High Temperature Variable Conductance Heat Pipes for Radioisotope Stirling Systems

    NASA Technical Reports Server (NTRS)

    Tarau, Calin; Walker, Kara L.; Anderson, William G.

    2009-01-01

    In a Stirling radioisotope system, heat must continually be removed from the GPHS modules, to maintain the GPHS modules and surrounding insulation at acceptable temperatures. Normally, the Stirling convertor provides this cooling. If the Stirling convertor stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS, but also ending the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) is under development to allow multiple stops and restarts of the Stirling convertor. The status of the ongoing effort in developing this technology is presented in this paper. An earlier, preliminary design had a radiator outside the Advanced Stirling Radioisotope Generator (ASRG) casing, used NaK as the working fluid, and had the reservoir located on the cold side adapter flange. The revised design has an internal radiator inside the casing, with the reservoir embedded inside the insulation. A large set of advantages are offered by this new design. In addition to reducing the overall size and mass of the VCHP, simplicity, compactness and easiness in assembling the VCHP with the ASRG are significantly enhanced. Also, the permanently elevated temperatures of the entire VCHP allows the change of the working fluid from a binary compound (NaK) to single compound (Na). The latter, by its properties, allows higher performance and further mass reduction of the system. Preliminary design and analysis shows an acceptable peak temperature of the ASRG case of 140 C while the heat losses caused by the addition of the VCHP are 1.8 W.

  15. Assessment of the structure and variability of Weddell Sea water masses in distinct ocean reanalysis products

    NASA Astrophysics Data System (ADS)

    Dotto, T. S.; Kerr, R.; Mata, M. M.; Azaneu, M.; Wainer, I.

    2014-02-01

    We assessed and evaluated the performance of five ocean reanalysis in reproducing essential hydrographic properties and their associated temporal variability for the Weddell Sea, Antarctica. The products used in this assessment were ECMWF ORAS4, CFSR, MyOcean UR025.4, ECCO2 and SODA. The present study focuses on the Weddell Sea deep layer, which is composed of the following three main water masses: Warm Deep Water (WDW), Weddell Sea Deep Water (WSDW) and Weddell Sea Bottom Water (WSBW). Moreover, all the ocean reanalysis products analyzed showed limited capabilities in representing the surface water masses in the Weddell Sea. The MyOcean UR025.4 product provided the most accurate representation of the structure of the Weddell Sea water masses when compared to observations. The CFSR and ECCO2 products were not able to represent the WSBW throughout the simulation period. The expected WDW warming was only reproduced by the SODA product, while the ECCO2 product was able to represent the WSDW's hydrographic properties trends. All of these ocean reanalysis systems were able to represent the decrease in the WSBW's density. Our results also showed that a simple increase in horizontal resolution does not necessarily imply better representation of the deep layers. Rather, it is needed to observe the physics involved in each model and their parameterizations because the Southern Ocean suffers from the lack of in situ data, and it is biased by summer observations. The choice of the reanalysis product should be made carefully, taking into account the performance, the parameters of interest, and the type of physical processes to be evaluated.

  16. Superintegrable systems with position dependent mass

    E-print Network

    A. G. Nikitin; T. M. Zasadko

    2015-03-27

    First order integrals of motion for Schr\\"odinger equations with position dependent masses are classified. Seventeen classes of such equations with non-equivalent symmetries are specified. They include integrable, superintegrable and maximally superintegrable systems. Among them is a system invariant with respect to the Lie algebra of Lorentz group and a system whose integrals of motion form algebra so(4). Three of the obtained systems are solved exactly.

  17. An analysis of space power system masses

    SciTech Connect

    Kenny, B.H.; Cull, R.C.; Kankam, M.D.

    1990-01-01

    Various space electrical power system masses are analyzed with particular emphasis on the power management and distribution (PMAD) portion. The electrical power system (EPS) is divided into functional blocks: source, interconnection, storage, transmission, distribution, system control and load. The PMAD subsystem is defined as all the blocks between the source, storage and load, plus the power conditioning equipment required for the source, storage and load. The EPS mass of a wide range of spacecraft is then classified as source, storage or PMAD and tabulated in a database. The intent of the database is to serve as a reference source for PMAD masses of existing and in-design spacecraft. The PMAD masses in the database range from 40 kg/kW to 183 kg/kW across the spacecraft systems studied. Factors influencing the power system mass are identified. These include the total spacecraft power requirements, total amount of load capacity and physical size of the spacecraft. It is found that a new utility class of power systems, represented by Space Station Freedom, is evolving.

  18. Dark-Spot Activity on the Secondary as the Origin of Variable Mass Accretion in Cataclysmic Variables

    NASA Astrophysics Data System (ADS)

    Qian, S.-B.; Zhu, L.-Y.; Fernández-Lajús, E.; He, J.-J.; Liao, W.-P.; Zhao, E.-G.; Liu, L.; Yang, Y.-G.

    2014-08-01

    In magnetic CVs (polars), the magnetic fields of the white dwarfs are strong enough to prevent materials from the main-sequence companions for forming an accretion disc. Therefore, polars especially eclipsing polars provide a good chance to study mass accretion directly. In the past 4 years, we have monitored several eclipsing polars (e.g., DP Leo and HU Aqr) by using the 2.4-m and 1.0-m telescopes in China and the 2.15-m telescope in Argentina. Nearly 100 eclipse profiles were obtained. In this talk, apart from the detection of a few giant planets orbiting polars, I will summarize some other progresses of our research group at Yunnan Observatories. Our results are as following: (1) the correlation between the out-of-eclipse brightness variation and the change of the eclipse profile suggests that both the accretion hot spot and the accretion stream brighten and become faint instantaneously. This is the direct evidence of variable mass transfer in a CV that is also supported by the relation between the out-of-eclipse brightness and the depth of eclipse. (2) We find the brightness state change is correlated with the dark-spot activity near the L1 point. The low state usually corresponds to the presence of a large spot at L1 point, while the dark spot disappear at a high state indicating that it is the dark-spot activity caused the mass transfer in CVs. (3) Magnetic activity cycles of the cool secondary did not correlate with the brightness state change revealing the variable mass accretion was not caused by magnetic activity cycles.

  19. System-Level Integration of Mass Memory

    NASA Technical Reports Server (NTRS)

    Cox, Brian; Mellstrom, Jeffrey; Wysocky, Terry

    2008-01-01

    A report discusses integrating multiple memory modules on the high-speed serial interconnect (IEEE 1393) that is used by a spacecraft?s inter-module communications in order to ease data congestion and provide for a scalable, strong, flexible system that can meet new system-level mass memory requirements.

  20. Mesoscale variability of water masses in the Arabian Sea as revealed by ARGO floats

    Microsoft Academic Search

    X. Carton; P. L'Hegaret

    2011-01-01

    By analysing ARGO float data over the last four years, some aspects of the mesoscale variability of water masses in the Arabian Sea are described. The Red Sea Water outflow is strong in the Southwestern Gulf of Aden, in particular when a cyclonic gyre predominates in this region. Salinities of 36.5 and temperatures of 16 °C are found there between

  1. Stability of North Atlantic water masses in face of pronounced climate variability during the Pleistocene

    E-print Network

    South Florida, University of

    , 4850); 1620 Global Change: Climate dynamics (3309); 3344 Meteorology and Atmospheric DynamicsStability of North Atlantic water masses in face of pronounced climate variability during and iceberg delivery from nearby landmasses. The most anomalous d13 C profiles are from the extreme

  2. Infrared Properties of Cataclysmic Variables in the 2MASS All Sky Data Release

    E-print Network

    D. W. Hoard; C. S. Brinkworth; S. Wachter

    2004-09-28

    We present results from our analysis of the near-infrared (J, H, and Ks) photometry for all cataclysmic variables from the catalog of Downes et al. (2001) that are detected in the (final) All Sky Data Release from the Two Micron All Sky Survey (2MASS).

  3. FEATHER GROWTH RATE AND MASS IN NEARCTIC PASSERINES WITH VARIABLE MIGRATORY BEHAVIOR AND MOLT PATTERN

    E-print Network

    DeSante, David F.

    FEATHER GROWTH RATE AND MASS IN NEARCTIC PASSERINES WITH VARIABLE MIGRATORY BEHAVIOR AND MOLT ptilochronology-based measurements of the growth rate of their tail feathers. We used between molt duration and feather quality, observed variation in feather growth rate was positively

  4. Optical intra-day variability timescales and black hole mass of the blazars

    NASA Astrophysics Data System (ADS)

    Gupta, S. P.; Pandey, U. S.; Singh, K.; Rani, B.; Pan, J.; Fan, J. H.; Gupta, A. C.

    2012-01-01

    In this paper, we have used optical intra-day variability archive data to calculate the central black hole masses and Eddington luminosities for nine blazars: 3C 66A, AO 0235+164, S5 0716+714, PKS 0735+178, OJ 287, 1215+303, 1216-010, 1308+326, PKS 1510-089, Mrk 501 and BL Lac using intra-day variability timescales and periodicity (if present). The calculated central black hole mass of these nine blazars using intra-day variability timescales are found to be in the range of 1.22-25.30 × 10 7 M ? and corresponding Eddington luminosity in the range of 1.58-32.88 × 10 45 erg s -1. The black hole mass and Eddington luminosity are in the range of 0.32-31.23 × 10 8 M ? and 1.23-31.20 × 10 46 erg s -1, respectively when optical Doppler factor is taken into account. The comparison show, our estimated values of black hole mass are consistent with earlier reported values. Periodicity were present in two blazars OJ 287 and 1216-010 which give the central black hole mass of these blazars in the range of 1.32-14.6 × 10 7 M ? and corresponding Eddington luminosity in the range of 1.60-19.0 × 10 45 erg s -1, respectively.

  5. Minimal variability time scale - central black hole mass relation of the ?-ray loud blazars

    NASA Astrophysics Data System (ADS)

    Vovk, Ievgen; Babi?, Ana

    2015-06-01

    Context. The variability time scales of the blazar ?-ray emission contain the imprints of the sizes of their emission zones and are generally expected to be larger than the light-crossing times of these zones. In several cases the time scales were found to be as short ~ 10 min, suggesting that the emission zone sizes are comparable with the sizes of the central supermassive black holes. Previously, these measurements also led to the suggestion of a possible connection between the observed minimal variability time scales and the masses of the corresponding black holes. This connection can be used to determine the location of the ?-ray emission site, which currently remains uncertain. Aims: The study aims to investigate the suggested "minimum time scale - black hole mass" relation using the blazars, detected in the TeV band. Methods: To obtain the tightest constraints on the variability time scales this work uses a compilation of observations by the Cherenkov telescopes HESS, MAGIC, and VERITAS. These measurements are compared to the blazar central black hole masses found in the literature. Results: The majority of the studied blazars show the variability time scales which are at least comparable to the period of rotation along the last stable orbit of the central black hole - and in some cases as short as its light-crossing time. For several sources the observed variability time scales are found to be smaller than the black hole light-crossing time. This suggests that the detected ?-ray variability originates, most probably, from the turbulence in the jet, sufficiently far from the central black hole.

  6. Mass Transit Living Lab: Improve the System

    NSDL National Science Digital Library

    Civil and Environmental Engineering Department,

    Students go through the process of identifying possible solutions to the design problems that the existing west corridor transit system faces. Students combine what they have learned from the three previous activities to come up with possible solutions to the design problems faced by the system. This activity requires the use of the Mass Transit Living Lab—a web portal to interactive train (transit) traffic data for a major metropolitan city.

  7. Variable frequency microwave curing in polymer systems

    SciTech Connect

    McMillan, A.D.; Lauf, R.J.; Paulauskas, F.L. [Oak Ridge National Lab., TN (United States)] [and others

    1995-12-01

    Problems with the uniformity of cure obtained in multimode ovens operating at 2.45 GHz have been overcome by utilizing Variable Frequency Microwave Processing. Hardness tests confirm DSC measurements that full cure and properties equivalent to conventional processing can be obtained. A batch up to 530g was successfully cured in 50 minutes using this technology, demonstrating large scale, efficient processing.

  8. Toward Scalable Benchmarks for Mass Storage Systems

    NASA Technical Reports Server (NTRS)

    Miller, Ethan L.

    1996-01-01

    This paper presents guidelines for the design of a mass storage system benchmark suite, along with preliminary suggestions for programs to be included. The benchmarks will measure both peak and sustained performance of the system as well as predicting both short- and long-term behavior. These benchmarks should be both portable and scalable so they may be used on storage systems from tens of gigabytes to petabytes or more. By developing a standard set of benchmarks that reflect real user workload, we hope to encourage system designers and users to publish performance figures that can be compared with those of other systems. This will allow users to choose the system that best meets their needs and give designers a tool with which they can measure the performance effects of improvements to their systems.

  9. Shock wave interpretation of emission lines in long period variable stars. II. Periodicity and mass loss

    Microsoft Academic Search

    L. A. Willson; S. J. Hill

    1979-01-01

    An analytical description of strictly periodic shock waves passing through a stellar atmosphere is developed which allows predictions to be made of the onset of instability of the system against mass loss by hydrodynamic ejection. This diagnostic method for determining when shock-driven mass loss may be expected is compared to several numerical isothermal hydrodynamical models. The predictions by the analytical

  10. The Secondary Star in Cataclysmic Variables and Low Mass X-ray Binaries

    E-print Network

    D. A. Smith; V. S. Dhillon

    1998-08-20

    We critically re-examine the available data on the spectral types, masses and radii of the secondary stars in cataclysmic variables (CVs) and low-mass X-ray binaries (LMXBs), using the new catalogue of Ritter & Kolb (1998) as a starting point. We find there are 55 reliable spectral type determinations and only 14 reliable mass determinations of CV secondary stars (10 and 5, respectively, in the case of LMXBs). We derive new spectral type-period, mass-radius, mass-period and radius-period relations, and compare them with theoretical predictions. We find that CV secondary stars with orbital periods shorter than 7-8 hours are, as a group, indistinguishable from main sequence stars in detached binaries. We find it is not valid, however, to estimate the mass from the spectral type of the secondary star in CVs or LMXBs. We find that LMXB secondary stars show some evidence for evolution, with secondary stars which are slightly too large for their mass. We show how the masses and radii of the secondary stars in CVs can be used to test the validity of the disrupted magnetic braking model of CV evolution, but we find that the currently available data are not sufficiently accurate or numerous to allow such an analysis. As well as considering secondary star masses, we also discuss the masses of the white dwarfs in CVs, and find mean values of M_1 = 0.69+/-0.13 M_sun below the period gap, and M_1 = 0.80+/-0.22 M_sun above the period gap.

  11. Using System Mass (SM), Equivalent Mass (EM), Equivalent System Mass (ESM) or Life Cycle Mass (LCM) in Advanced Life Support (ALS) Reporting

    NASA Technical Reports Server (NTRS)

    Jones, Harry

    2003-01-01

    The Advanced Life Support (ALS) has used a single number, Equivalent System Mass (ESM), for both reporting progress and technology selection. ESM is the launch mass required to provide a space system. ESM indicates launch cost. ESM alone is inadequate for technology selection, which should include other metrics such as Technology Readiness Level (TRL) and Life Cycle Cost (LCC) and also consider perfom.arxe 2nd risk. ESM has proven difficult to implement as a reporting metric, partly because it includes non-mass technology selection factors. Since it will not be used exclusively for technology selection, a new reporting metric can be made easier to compute and explain. Systems design trades-off performance, cost, and risk, but a risk weighted cost/benefit metric would be too complex to report. Since life support has fixed requirements, different systems usually have roughly equal performance. Risk is important since failure can harm the crew, but it is difficult to treat simply. Cost is not easy to estimate, but preliminary space system cost estimates are usually based on mass, which is better estimated than cost. Amass-based cost estimate, similar to ESM, would be a good single reporting metric. The paper defines and compares four mass-based cost estimates, Equivalent Mass (EM), Equivalent System Mass (ESM), Life Cycle Mass (LCM), and System Mass (SM). EM is traditional in life support and includes mass, volume, power, cooling and logistics. ESM is the specifically defined ALS metric, which adds crew time and possibly other cost factors to EM. LCM is a new metric, a mass-based estimate of LCC measured in mass units. SM includes only the factors of EM that are originally measured in mass, the hardware and logistics mass. All four mass-based metrics usually give similar comparisons. SM is by far the simplest to compute and easiest to explain.

  12. Application of Variable Structure Control in Missile Electromechanical Actuator System

    Microsoft Academic Search

    Yuan Gao; Liang-xian Gu; Lei Pan

    2008-01-01

    Parameter variation and load disturbance will have great influence on the performance of missile electromechanical actuator system and further on the performance of the entire missile system during the missile flight process. To solve this problem, a variable structure control system for missile electromechanical actuator system was proposed in this paper. To verify the proposed control scheme, simulation has been

  13. HYDRAULIC POSITION CONTROL SYSTEM WITH VARIABLE SPEED PUMP

    Microsoft Academic Search

    Tuna BALKAN; Bülent E. PLAT?N

    In this study, a valveless energy saving hydraulic position control servo system controlled by two pumps is investigated. In this system, two variable speed pumps driven by servomotors regulate the flow rate through a differential cylinder according to the needs of the system, thus eliminating the valve losses. The mathematical model of the system is developed in MATLAB Simulink environment.

  14. A NEW SAMPLE OF CANDIDATE INTERMEDIATE-MASS BLACK HOLES SELECTED BY X-RAY VARIABILITY

    SciTech Connect

    Kamizasa, Naoya; Terashima, Yuichi; Awaki, Hisamitsu [Department of Physics, Ehime University, Matsuyama, Ehime 790-8577 (Japan)

    2012-05-20

    We present the results of X-ray variability and spectral analysis of a sample of 15 new candidates for active galactic nuclei with relatively low-mass black holes (BHs). They are selected from the Second XMM-Newton Serendipitous Source Catalogue based on strong variability quantified by normalized excess variances. Their BH masses are estimated to be (1.1-6.6) Multiplication-Sign 10{sup 6} M{sub Sun} by using a correlation between excess variance and BH mass. Seven sources have estimated BH masses smaller than 2 Multiplication-Sign 10{sup 6} M{sub Sun }, which are in the range for intermediate-mass black holes. Eddington ratios of sources with known redshifts range from 0.07 to 0.46 and the mean Eddington ratio is 0.24. These results imply that some of our sources are growing supermassive black holes, which are expected to have relatively low masses with high Eddington ratios. X-ray photon indices of the 15 sources are in the range of Almost-Equal-To 0.57-2.57 and 5 among them have steep (>2) photon indices, which are the range for narrow-line Seyfert 1s. Soft X-ray excess is seen in 12 sources and is expressed by a blackbody model with kT Almost-Equal-To 83-294 eV. We derive a correlation between X-ray photon indices and Eddington ratios, and find that the X-ray photon indices of about a half of our sources are flatter than the positive correlation suggested previously.

  15. Variable Static Pressure-Coordinating Control for Variable Air Volume Air-conditioning System

    Microsoft Academic Search

    A'ni Dong; Qinhua Hu; Qingchang Ren

    2006-01-01

    Of all the building automation systems, heating, ventilating and air-conditioning systems (HVAC) are most important from the viewpoint of saving energy and improving the quality of the indoor environment. Therefore, adopting efficient control strategies for air-conditioning plays a vital role in developing improved energy management control systems(EMC) for intelligent buildings. At present, variable air volume (VAV) air-conditioning system is the

  16. MASS ACTION IN THE NERVOUS SYSTEM WALTER J. FREEMAN

    E-print Network

    Freeman, Walter J.

    MASS ACTION IN THE NERVOUS SYSTEM in the nervous system. Bibliography: p. Includes indexes. Neurophysiologyâ??Mathematical models. Adaptation IN THE UNITED STATES OF AMERICA #12; MASS ACTION IN THE NERVOUS SYSTEM Contents PREFACE

  17. Expert overseer for mass spectrometer system

    DOEpatents

    Filby, Evan E. (Idaho Falls, ID); Rankin, Richard A. (Ammon, ID)

    1991-01-01

    An expert overseer for the operation and real-time management of a mass spectrometer and associated laboratory equipment. The overseer is a computer-based expert diagnostic system implemented on a computer separate from the dedicated computer used to control the mass spectrometer and produce the analysis results. An interface links the overseer to components of the mass spectrometer, components of the laboratory support system, and the dedicated control computer. Periodically, the overseer polls these devices and as well as itself. These data are fed into an expert portion of the system for real-time evaluation. A knowledge base used for the evaluation includes both heuristic rules and precise operation parameters. The overseer also compares current readings to a long-term database to detect any developing trends using a combination of statistical and heuristic rules to evaluate the results. The overseer has the capability to alert lab personnel whenever questionable readings or trends are observed and provide a background review of the problem and suggest root causes and potential solutions, or appropriate additional tests that could be performed. The overseer can change the sequence or frequency of the polling to respond to an observation in the current data.

  18. Solving Systems of Linear Equations in Two Variables

    NSDL National Science Digital Library

    This tutorial on solving systems of linear equations in two variables walks students through each step of solving, and provides a handy video lesson at the end in which an instructor guides the viewer through the solution.

  19. Burner Designs and Controls for Variable Air Preheat Systems 

    E-print Network

    Lied, C. R.

    1981-01-01

    and batch type melting operations resulting in cyclic or variable air preheat temperatures will be discussed. Fuel savings relating to the use of recuperation and various types of fuel/air ratio systems will also be discussed....

  20. Mass spectrometer vacuum housing and pumping system

    DOEpatents

    Coutts, Gerald W. (Livermore, CA); Bushman, John F. (Oakley, CA); Alger, Terry W. (Tracy, CA)

    1996-01-01

    A vacuum housing and pumping system for a portable gas chromatograph/mass spectrometer (GC/MS). The vacuum housing section of the system has minimum weight for portability while designed and constructed to utilize metal gasket sealed stainless steel to be compatible with high vacuum operation. The vacuum pumping section of the system consists of a sorption (getter) pump to remove atmospheric leakage and outgassing contaminants as well as the gas chromatograph carrier gas (hydrogen) and an ion pump to remove the argon from atmospheric leaks. The overall GC/MS system has broad application to contaminants, hazardous materials, illegal drugs, pollution monitoring, etc., as well as for use by chemical weapon treaty verification teams, due to the light weight and portability thereof.

  1. Mass spectrometer vacuum housing and pumping system

    DOEpatents

    Coutts, G.W.; Bushman, J.F.; Alger, T.W.

    1996-07-23

    A vacuum housing and pumping system is described for a portable gas chromatograph/mass spectrometer (GC/MS). The vacuum housing section of the system has minimum weight for portability while designed and constructed to utilize metal gasket sealed stainless steel to be compatible with high vacuum operation. The vacuum pumping section of the system consists of a sorption (getter) pump to remove atmospheric leakage and outgassing contaminants as well as the gas chromatograph carrier gas (hydrogen) and an ion pump to remove the argon from atmospheric leaks. The overall GC/MS system has broad application to contaminants, hazardous materials, illegal drugs, pollution monitoring, etc., as well as for use by chemical weapon treaty verification teams, due to the light weight and portability thereof. 7 figs.

  2. Re-interpreting the Oxbridge stransverse mass variable M T2 in general cases

    NASA Astrophysics Data System (ADS)

    Mahbubani, Rakhi; Matchev, Konstantin T.; Park, Myeonghun

    2013-03-01

    We extend the range of possible applications of M T2 type analyses to decay chains with multiple invisible particles, as well as to asymmetric event topologies with different parent and/or different children particles. We advocate two possible approaches. In the first, we introduce suitably defined 3 + 1-dimensional analogues of the M T2 variable, which take into account all relevant on-shell kinematic constraints in a given event topology. The second approach utilizes the conventional M T2 variable, but its kinematic endpoint is suitably reinterpreted on a case by case basis, depending on the specific event topology at hand. We provide the general prescription for this reinterpretation, including the formulas relating the measured M T2 endpoint (as a function of the test masses of all the invisible particles) to the underlying physical mass spectrum. We also provide analytical formulas for the shape of the differential distribution of the doubly projected {M_{{T{2_{bot }}}}} variable for the ten possible event topologies with one visible particle and up to two invisible particles per decay chain. We illustrate our results with the example of leptonic chargino decays {{widetilde{?}}+}to {ell+}? {{widetilde{?}}^0} in supersymmetry.

  3. On-shell constrained M 2 variables with applications to mass measurements and topology disambiguation

    NASA Astrophysics Data System (ADS)

    Cho, Won Sang; Gainer, James S.; Kim, Doojin; Matchev, Konstantin T.; Moortgat, Filip; Pape, Luc; Park, Myeonghun

    2014-08-01

    We consider a class of on-shell constrained mass variables that are 3+1 dimensional generalizations of the Cambridge M T2 variable and that automatically incorporate various assumptions about the underlying event topology. The presence of additional on-shell constraints causes their kinematic distributions to exhibit sharper endpoints than the usual M T2 distribution. We study the mathematical properties of these new variables, e.g., the uniqueness of the solution selected by the minimization over the invisible particle 4-momenta. We then use this solution to reconstruct the masses of various particles along the decay chain. We propose several tests for validating the assumed event topology in missing energy events from new physics. The tests are able to determine: 1) whether the decays in the event are two-body or three-body, 2) if the decay is two-body, whether the intermediate resonances in the two decay chains are the same, and 3) the exact sequence in which the visible particles are emitted from each decay chain.

  4. FTO genotype is associated with phenotypic variability of body mass index

    PubMed Central

    Yang, Jian; Loos, Ruth J. F.; Powell, Joseph E.; Medland, Sarah E.; Speliotes, Elizabeth K.; Chasman, Daniel I.; Rose, Lynda M.; Thorleifsson, Gudmar; Steinthorsdottir, Valgerdur; Mägi, Reedik; Waite, Lindsay; Smith, Albert Vernon; Yerges-Armstrong, Laura M.; Monda, Keri L.; Hadley, David; Mahajan, Anubha; Li, Guo; Kapur, Karen; Vitart, Veronique; Huffman, Jennifer E.; Wang, Sophie R.; Palmer, Cameron; Esko, Tõnu; Fischer, Krista; Zhao, Jing Hua; Demirkan, Ay?e; Isaacs, Aaron; Feitosa, Mary F.; Luan, Jian’an; Heard-Costa, Nancy L.; White, Charles; Jackson, Anne U.; Preuss, Michael; Ziegler, Andreas; Eriksson, Joel; Kutalik, Zoltán; Frau, Francesca; Nolte, Ilja M.; Van Vliet-Ostaptchouk, Jana V.; Hottenga, Jouke-Jan; Jacobs, Kevin B.; Verweij, Niek; Goel, Anuj; Medina-Gomez, Carolina; Estrada, Karol; Bragg-Gresham, Jennifer Lynn; Sanna, Serena; Sidore, Carlo; Tyrer, Jonathan; Teumer, Alexander; Prokopenko, Inga; Mangino, Massimo; Lindgren, Cecilia M.; Assimes, Themistocles L.; Shuldiner, Alan R.; Hui, Jennie; Beilby, John P.; McArdle, Wendy L.; Hall, Per; Haritunians, Talin; Zgaga, Lina; Kolcic, Ivana; Polasek, Ozren; Zemunik, Tatijana; Oostra, Ben A.; Junttila, M. Juhani; Grönberg, Henrik; Schreiber, Stefan; Peters, Annette; Hicks, Andrew A.; Stephens, Jonathan; Foad, Nicola S.; Laitinen, Jaana; Pouta, Anneli; Kaakinen, Marika; Willemsen, Gonneke; Vink, Jacqueline M.; Wild, Sarah H.; Navis, Gerjan; Asselbergs, Folkert W.; Homuth, Georg; John, Ulrich; Iribarren, Carlos; Harris, Tamara; Launer, Lenore; Gudnason, Vilmundur; O’Connell, Jeffrey R.; Boerwinkle, Eric; Cadby, Gemma; Palmer, Lyle J.; James, Alan L.; Musk, Arthur W.; Ingelsson, Erik; Psaty, Bruce M.; Beckmann, Jacques S.; Waeber, Gerard; Vollenweider, Peter; Hayward, Caroline; Wright, Alan F.; Rudan, Igor; Groop, Leif C.; Metspalu, Andres; Khaw, Kay Tee; van Duijn, Cornelia M.; Borecki, Ingrid B.; Province, Michael A.; Wareham, Nicholas J.; Tardif, Jean-Claude; Huikuri, Heikki V.; Cupples, L. Adrienne; Atwood, Larry D.; Fox, Caroline S.; Boehnke, Michael; Collins, Francis S.; Mohlke, Karen L.; Erdmann, Jeanette; Schunkert, Heribert; Hengstenberg, Christian; Stark, Klaus; Lorentzon, Mattias; Ohlsson, Claes; Cusi, Daniele; Staessen, Jan A.; Van der Klauw, Melanie M.; Pramstaller, Peter P.; Kathiresan, Sekar; Jolley, Jennifer D.; Ripatti, Samuli; Jarvelin, Marjo-Riitta; de Geus, Eco J. C.; Boomsma, Dorret I.; Penninx, Brenda; Wilson, James F.; Campbell, Harry; Chanock, Stephen J.; van der Harst, Pim; Hamsten, Anders; Watkins, Hugh; Hofman, Albert; Witteman, Jacqueline C.; Zillikens, M. Carola; Uitterlinden, André G.; Rivadeneira, Fernando; Zillikens, M. Carola; Kiemeney, Lambertus A.; Vermeulen, Sita H.; Abecasis, Goncalo R.; Schlessinger, David; Schipf, Sabine; Stumvoll, Michael; Tönjes, Anke; Spector, Tim D.; North, Kari E.; Lettre, Guillaume; McCarthy, Mark I.; Berndt, Sonja I.; Heath, Andrew C.; Madden, Pamela A. F.; Nyholt, Dale R.; Montgomery, Grant W.; Martin, Nicholas G.; McKnight, Barbara; Strachan, David P.; Hill, William G.; Snieder, Harold; Ridker, Paul M.; Thorsteinsdottir, Unnur; Stefansson, Kari; Frayling, Timothy M.; Hirschhorn, Joel N.; Goddard, Michael E.; Visscher, Peter M.

    2013-01-01

    There is evidence across several species for genetic control of phenotypic variation of complex traits1–4, such that the variance among phenotypes is genotype dependent. Understanding genetic control of variability is important in evolutionary biology, agricultural selection programmes and human medicine, yet for complex traits, no individual genetic variants associated with variance, as opposed to the mean, have been identified. Here we perform a meta-analysis of genome-wide association studies of phenotypic variation using 170,000 samples on height and body mass index (BMI) in human populations. We report evidence that the single nucleotide polymorphism (SNP) rs7202116 at the FTO gene locus, which is known to be associated with obesity (as measured by mean BMI for each rs7202116 genotype)5–7, is also associated with phenotypic variability. We show that the results are not due to scale effects or other artefacts, and find no other experiment-wise significant evidence for effects on variability, either at loci other than FTO for BMI or at any locus for height. The difference in variance for BMI among individuals with opposite homozygous genotypes at the FTO locus is approximately 7%, corresponding to a difference of 0.5 kilograms in the standard deviation of weight. Our results indicate that genetic variants can be discovered that are associated with variability, and that between-person variability in obesity can partly be explained by the genotype at the FTO locus. The results are consistent with reported FTO by environment interactions for BMI8, possibly mediated by DNA methylation9,10. Our BMI results for other SNPs and our height results for all SNPs suggest that most genetic variants, including those that influence mean height or mean BMI, are not associated with phenotypic variance, or that their effects on variability are too small to detect even with samples sizes greater than 100,000. PMID:22982992

  5. FTO genotype is associated with phenotypic variability of body mass index.

    PubMed

    Yang, Jian; Loos, Ruth J F; Powell, Joseph E; Medland, Sarah E; Speliotes, Elizabeth K; Chasman, Daniel I; Rose, Lynda M; Thorleifsson, Gudmar; Steinthorsdottir, Valgerdur; Mägi, Reedik; Waite, Lindsay; Smith, Albert Vernon; Yerges-Armstrong, Laura M; Monda, Keri L; Hadley, David; Mahajan, Anubha; Li, Guo; Kapur, Karen; Vitart, Veronique; Huffman, Jennifer E; Wang, Sophie R; Palmer, Cameron; Esko, Tõnu; Fischer, Krista; Zhao, Jing Hua; Demirkan, Ay?e; Isaacs, Aaron; Feitosa, Mary F; Luan, Jian'an; Heard-Costa, Nancy L; White, Charles; Jackson, Anne U; Preuss, Michael; Ziegler, Andreas; Eriksson, Joel; Kutalik, Zoltán; Frau, Francesca; Nolte, Ilja M; Van Vliet-Ostaptchouk, Jana V; Hottenga, Jouke-Jan; Jacobs, Kevin B; Verweij, Niek; Goel, Anuj; Medina-Gomez, Carolina; Estrada, Karol; Bragg-Gresham, Jennifer Lynn; Sanna, Serena; Sidore, Carlo; Tyrer, Jonathan; Teumer, Alexander; Prokopenko, Inga; Mangino, Massimo; Lindgren, Cecilia M; Assimes, Themistocles L; Shuldiner, Alan R; Hui, Jennie; Beilby, John P; McArdle, Wendy L; Hall, Per; Haritunians, Talin; Zgaga, Lina; Kolcic, Ivana; Polasek, Ozren; Zemunik, Tatijana; Oostra, Ben A; Junttila, M Juhani; Grönberg, Henrik; Schreiber, Stefan; Peters, Annette; Hicks, Andrew A; Stephens, Jonathan; Foad, Nicola S; Laitinen, Jaana; Pouta, Anneli; Kaakinen, Marika; Willemsen, Gonneke; Vink, Jacqueline M; Wild, Sarah H; Navis, Gerjan; Asselbergs, Folkert W; Homuth, Georg; John, Ulrich; Iribarren, Carlos; Harris, Tamara; Launer, Lenore; Gudnason, Vilmundur; O'Connell, Jeffrey R; Boerwinkle, Eric; Cadby, Gemma; Palmer, Lyle J; James, Alan L; Musk, Arthur W; Ingelsson, Erik; Psaty, Bruce M; Beckmann, Jacques S; Waeber, Gerard; Vollenweider, Peter; Hayward, Caroline; Wright, Alan F; Rudan, Igor; Groop, Leif C; Metspalu, Andres; Khaw, Kay Tee; van Duijn, Cornelia M; Borecki, Ingrid B; Province, Michael A; Wareham, Nicholas J; Tardif, Jean-Claude; Huikuri, Heikki V; Cupples, L Adrienne; Atwood, Larry D; Fox, Caroline S; Boehnke, Michael; Collins, Francis S; Mohlke, Karen L; Erdmann, Jeanette; Schunkert, Heribert; Hengstenberg, Christian; Stark, Klaus; Lorentzon, Mattias; Ohlsson, Claes; Cusi, Daniele; Staessen, Jan A; Van der Klauw, Melanie M; Pramstaller, Peter P; Kathiresan, Sekar; Jolley, Jennifer D; Ripatti, Samuli; Jarvelin, Marjo-Riitta; de Geus, Eco J C; Boomsma, Dorret I; Penninx, Brenda; Wilson, James F; Campbell, Harry; Chanock, Stephen J; van der Harst, Pim; Hamsten, Anders; Watkins, Hugh; Hofman, Albert; Witteman, Jacqueline C; Zillikens, M Carola; Uitterlinden, André G; Rivadeneira, Fernando; Zillikens, M Carola; Kiemeney, Lambertus A; Vermeulen, Sita H; Abecasis, Goncalo R; Schlessinger, David; Schipf, Sabine; Stumvoll, Michael; Tönjes, Anke; Spector, Tim D; North, Kari E; Lettre, Guillaume; McCarthy, Mark I; Berndt, Sonja I; Heath, Andrew C; Madden, Pamela A F; Nyholt, Dale R; Montgomery, Grant W; Martin, Nicholas G; McKnight, Barbara; Strachan, David P; Hill, William G; Snieder, Harold; Ridker, Paul M; Thorsteinsdottir, Unnur; Stefansson, Kari; Frayling, Timothy M; Hirschhorn, Joel N; Goddard, Michael E; Visscher, Peter M

    2012-10-11

    There is evidence across several species for genetic control of phenotypic variation of complex traits, such that the variance among phenotypes is genotype dependent. Understanding genetic control of variability is important in evolutionary biology, agricultural selection programmes and human medicine, yet for complex traits, no individual genetic variants associated with variance, as opposed to the mean, have been identified. Here we perform a meta-analysis of genome-wide association studies of phenotypic variation using ?170,000 samples on height and body mass index (BMI) in human populations. We report evidence that the single nucleotide polymorphism (SNP) rs7202116 at the FTO gene locus, which is known to be associated with obesity (as measured by mean BMI for each rs7202116 genotype), is also associated with phenotypic variability. We show that the results are not due to scale effects or other artefacts, and find no other experiment-wise significant evidence for effects on variability, either at loci other than FTO for BMI or at any locus for height. The difference in variance for BMI among individuals with opposite homozygous genotypes at the FTO locus is approximately 7%, corresponding to a difference of ?0.5?kilograms in the standard deviation of weight. Our results indicate that genetic variants can be discovered that are associated with variability, and that between-person variability in obesity can partly be explained by the genotype at the FTO locus. The results are consistent with reported FTO by environment interactions for BMI, possibly mediated by DNA methylation. Our BMI results for other SNPs and our height results for all SNPs suggest that most genetic variants, including those that influence mean height or mean BMI, are not associated with phenotypic variance, or that their effects on variability are too small to detect even with samples sizes greater than 100,000. PMID:22982992

  6. Variable structure control of nonlinear systems: a new approach

    Microsoft Academic Search

    Weibing Gao; James C. Hung

    1993-01-01

    A new approach for the design of variable structure control (VSC) of nonlinear systems is presented. It is based on a new method called the reaching law method, and is complemented by a sliding-mode equivalence technique. They facilitate the design of the system dynamics in all three modes of a VSC system including the sliding, reaching, and steady-state modes. Invariance

  7. Mass Properties for Space Systems Standards Development

    NASA Technical Reports Server (NTRS)

    Beech, Geoffrey

    2013-01-01

    Current Verbiage in S-120 Applies to Dry Mass. Mass Margin is difference between Required Mass and Predicted Mass. Performance Margin is difference between Predicted Performance and Required Performance. Performance estimates and corresponding margin should be based on Predicted Mass (and other inputs). Contractor Mass Margin reserved from Performance Margin. Remaining performance margin allocated according to mass partials. Compliance can be evaluated effectively by comparison of three areas (preferably on a single sheet). Basic and Predicted Mass (including historical trend). Aggregate potential changes (threats and opportunities) which gives Mass Forecast. Mass Maturity by category (Estimated/Calculated/Actual).

  8. Improving the sensitivity of stop searches with on-shell constrained invariant mass variables

    NASA Astrophysics Data System (ADS)

    Cho, Won Sang; Gainer, James S.; Kim, Doojin; Matchev, Konstantin T.; Moortgat, Filip; Pape, Luc; Park, Myeonghun

    2015-05-01

    The search for light stops is of paramount importance, both in general as a promising path to the discovery of beyond the standard model physics and more specifically as a way of evaluating the success of the naturalness paradigm. While the LHC experiments have ruled out much of the relevant parameter space, there are "stop gaps", i.e., values of sparticle masses for which existing LHC analyses have relatively little sensitivity to light stops. We point out that techniques involving on-shell constrained M 2 variables can do much to enhance sensitivity in this region and hence help close the stop gaps. We demonstrate the use of these variables for several benchmark points and describe the effect of realistic complications, such as detector effects and combinatorial backgrounds, in order to provide a useful toolkit for light stop searches in particular, and new physics searches at the LHC in general.

  9. Bubble mass center and fluid feedback force fluctuations activated by constant lateral impulse with variable thrust

    NASA Technical Reports Server (NTRS)

    Hung, R. J.; Long, Y. T.

    1995-01-01

    Sloshing dynamics within a partially filled rotating dewar of superfluid helium 2 are investigated in response to constant lateral impulse with variable thrust. The study, including how the rotating bubble of superfluid helium 2 reacts to the constant impulse with variable time period of thrust action in microgravity, how amplitudes of bubble mass center fluctuates with growth and decay of disturbances, and how fluid feedback forces fluctuates in activating on the rotating dewar through the dynamics of sloshing waves are investigated. The numerical computation of sloshing dynamics is based on the non-inertial frame spacecraft bound coordinate with lateral impulses actuating on the rotating dewar in both inertial and non-inertial frames of thrust. Results of the simulations are illustrated.

  10. Atmospheric Low-Frequency Variability and Its Relationship to Midlatitude SST Variability: Studies Using the NCAR Climate System Model

    Microsoft Academic Search

    R. Saravanan

    1998-01-01

    The characteristics of atmospheric low-frequency variability and midlatitude SST variability as simulated by the National Center for Atmospheric Research's Climate System Model are analyzed in the vicinity of the North Pacific and North Atlantic basins. The simulated spatial patterns of variability correspond quite well to those seen in observational datasets, although there are some differences in the amplitudes of variability.

  11. Variability of local PM10 mass concentrations in connection with blocking air circulation

    NASA Astrophysics Data System (ADS)

    ?tefan, Sabina; Roman, Iuliana

    2015-06-01

    The aim of this paper is to analyze the temporal variability of Particulate Matter mass concentrations in connection with air circulation, for eight rural sites situated in the Central and Eastern parts of Europe. The stations from Poland, Hungary and Romania are rural stations without sources of pollutants. The analysis covers four winters, between December 2004 and February 2008. The pollution episodes were selected to explain air circulation influence. The results show that the causes of pollution were local, due to high mean sea level pressure and the blocking, as air circulation on large scale, was dominant in the cases of enhanced pollution in the selected area.

  12. Hawking Radiation of Dirac Particles in a Variable-mass Kerr Space-time

    E-print Network

    S. Q. Wu; X. Cai

    2001-04-18

    Hawking effect of Dirac particles in a variable-mass Kerr space-time is investigated by using a method called as the generalized tortoise coordinate transformation. The location and the temperature of the event horizon of the non-stationary Kerr black hole are derived. It is shown that the temperature and the shape of the event horizon depend not only on the time but also on the angle. However, the Fermi-Dirac spectrum displays a residual term which is absent from that of Bose-Einstein distribution.

  13. Spatial variability of hailfalls in France: an analysis of air mass retro-trajectories

    NASA Astrophysics Data System (ADS)

    Hermida, Lucía; Merino, Andrés; Sánchez, José Luis; Berthet, Claude; Dessens, Jean; López, Laura; Fernández-González, Sergio; Gascón, Estíbaliz; García-Ortega, Eduardo

    2014-05-01

    Hail is the main meteorological risk in south-west France, with the strongest hailfalls being concentrated in just a few days. Specifically, this phenomenon occurs most often and with the greatest severity in the Midi-Pyrénées area. Previous studies have revealed the high spatial variability of hailfall in this part of France, even leading to different characteristics being recorded on hailpads that were relatively close together. For this reason, an analysis of the air mass trajectories was carried out at ground level and at altitude, which subsequently led to the formation of the hail recorded by these hailpads. It is already known that in the study zone, the trajectories of the storms usually stretch for long distances and are oriented towards the east, leading to hailstones with diameters in excess of 3 cm, and without any change in direction above 3 km. We analysed different days with hail precipitation where there was at least one stone with a diameter of 3 cm or larger. Using the simulations from these days, an analysis of the backward trajectories of the air masses was carried out. We used the HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory Model) to determine the origin of the air masses, and tracked them toward each of the hailpads that were hit during the day studied. The height of the final points was the height of the impacted hailpads. Similarly, the backward trajectories for different heights were also established. Finally, the results show how storms that affect neighbouring hailpads come from very different air masses; and provide a deeper understanding of the high variability that affects the characteristics of hailfalls. Acknowledgements The authors would like to thank the Regional Government of Castile-León for its financial support through the project LE220A11-2. This study was supported by the following grants: GRANIMETRO (CGL2010-15930); MICROMETEO (IPT-310000-2010-22).

  14. New RR Lyrae variables in binary systems

    NASA Astrophysics Data System (ADS)

    Hajdu, G.; Catelan, M.; Jurcsik, J.; Dékány, I.; Drake, A. J.; Marquette, J.-B.

    2015-04-01

    Despite their importance, very few RR Lyrae (RRL) stars have been known to reside in binary systems. We report on a search for binary RRL in the OGLE-III Galactic bulge data. Our approach consists in the search for evidence of the light-travel time effect in so-called observed minus calculated (O-C) diagrams. Analysis of 1952 well-observed fundamental-mode RRL in the OGLE-III data revealed an initial sample of 29 candidates. We used the recently released OGLE-IV data to extend the baselines up to 17 yr, leading to a final sample of 12 firm binary candidates. We provide O-C diagrams and binary parameters for this final sample, and also discuss the properties of eight additional candidate binaries whose parameters cannot be firmly determined at present. We also estimate that ? 4 per cent of the RRL reside in binary systems.

  15. Fractal variability: An emergent property of complex dissipative systems

    NASA Astrophysics Data System (ADS)

    Seely, Andrew J. E.; Macklem, Peter

    2012-03-01

    The patterns of variation of physiologic parameters, such as heart and respiratory rate, and their alteration with age and illness have long been under investigation; however, the origin and significance of scale-invariant fractal temporal structures that characterize healthy biologic variability remain unknown. Quite independently, atmospheric and planetary scientists have led breakthroughs in the science of non-equilibrium thermodynamics. In this paper, we aim to provide two novel hypotheses regarding the origin and etiology of both the degree of variability and its fractal properties. In a complex dissipative system, we hypothesize that the degree of variability reflects the adaptability of the system and is proportional to maximum work output possible divided by resting work output. Reductions in maximal work output (and oxygen consumption) or elevation in resting work output (or oxygen consumption) will thus reduce overall degree of variability. Second, we hypothesize that the fractal nature of variability is a self-organizing emergent property of complex dissipative systems, precisely because it enables the system's ability to optimally dissipate energy gradients and maximize entropy production. In physiologic terms, fractal patterns in space (e.g., fractal vasculature) or time (e.g., cardiopulmonary variability) optimize the ability to deliver oxygen and clear carbon dioxide and waste. Examples of falsifiability are discussed, along with the need to further define necessary boundary conditions. Last, as our focus is bedside utility, potential clinical applications of this understanding are briefly discussed. The hypotheses are clinically relevant and have potential widespread scientific relevance.

  16. Evaluation of Small Mass Spectrometer Systems

    NASA Technical Reports Server (NTRS)

    Arkin, C. Richard; Griffin, Timothy P.; Ottens, Andrew K.; Diaz, Jorge A.; Follistein, Duke W.; Adams, Fredrick W.; Helms, William R.; Voska, N. (Technical Monitor)

    2002-01-01

    This work is aimed at understanding the aspects of designing a miniature mass spectrometer (MS) system. A multitude of commercial and government sectors, such as the military, environmental agencies and industrial manufacturers of semiconductors, refrigerants, and petroleum products, would find a small, portable, rugged and reliable MS system beneficial. Several types of small MS systems are evaluated and discussed, including linear quadrupole, quadrupole ion trap, time of flight and sector. The performance of each system in terms of accuracy, precision, limits of detection, response time, recovery time, scan rate, volume and weight is assessed. A performance scale is setup to rank each systems and an overall performance score is given to each system. All experiments involved the analysis of hydrogen, helium, oxygen and argon in a nitrogen background with the concentrations of the components of interest ranging from 0-5000 part-per-million (ppm). The relative accuracies of the systems vary from < 1% to approx. 40% with an average below 10%. Relative precisions varied from 1% to 20%, with an average below 5%. The detection limits had a large distribution, ranging from 0.2 to 170 ppm. The systems had a diverse response time ranging from 4 s to 210 s as did the recovery time with a 6 s to 210 s distribution. Most instruments had scan times near, 1 s, however one instrument exceeded 13 s. System weights varied from 9 to 52 kg and sizes from 15 x 10(exp 3)cu cm to 110 x 10(exp 3) cu cm.

  17. Low-Cost Automated Variable Star Detection System

    NASA Astrophysics Data System (ADS)

    Meades, Marin Nicole; Paust, Nathaniel

    2015-01-01

    We propose a method of variable star detection that utilizes automated data collection with affordable equipment and analysis using open source software. Our DSLR-based camera is currently opperating at Whitman College in Walla Walla, WA. At present, it collects a wide-field image roughly every 10 minutes throughout the day and night. The system observes stars near DEC=+44 and has a magnitude limit better than 8. This system has the possibility of characterizing bright long-period variables, important since the variability of many bright stars is unknown. We present this as a proof of concept and offer guidance for the large scale cataloguing of stars, enabling undergraduate students, amateur astronomers, etc. to make a meaninful contribution to the study of variable stars.

  18. Modified rock mass classification system by continuous rating

    Microsoft Academic Search

    Zekai ?en; Bahaaeldin H. Sadagah

    2003-01-01

    It is not the purpose of this paper to propose a new rock mass classification system but rather to improve the existing ones by incorporating some simple quantitative interpretations. The geomechanics classification system of naturally fractured rock masses is modified to decrease personal judgement involved in its calculation. Instead of six parameters in the classical rock mass rating (RMR) system,

  19. Evaluation of a center pivot variable rate irrigation system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Uniformity of water distribution of a variable rate center pivot irrigation system was evaluated. This 4-span center-pivot system was configured with 10 water application zones along its 766 ft-long lateral. Two experiments were conducted for the uniformity tests. In one test, a constant water appli...

  20. Variable Conductance Heat Pipes for Radioisotope Stirling Systems

    Microsoft Academic Search

    William G. Anderson; Calin Tarau

    2008-01-01

    In a Stirling radioisotope system, heat must continually be removed from the GPHS modules, to maintain the GPHS modules and surrounding insulation at acceptable temperatures. Normally, the Stirling convertor provides this cooling. If the Stirling engine stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS, but also ending the mission. An alkali-metal Variable

  1. Global Variability of Mesoscale Convective System

    NASA Technical Reports Server (NTRS)

    Yuan, J.; Houze, R. A., Jr.

    2010-01-01

    Mesoscale convective systems (MCSs) in the tropics produce extensive anvil clouds, which significantly affect the transfer of radiation. This study develops an objective method to identify MCSs and their anvils by combining data from three A-train satellite instruments: Moderate Resolution Imaging Spectroradiometer (MODIS) for cloud-top size and coldness, Advanced Microwave Scanning Radiometer for Earth Observing System (AMSR-E) for rain area size and intensity, and CloudSat for horizontal and vertical dimensions of anvils. The authors distinguish three types of MCSs: small and large separated MCSs and connected MCSs. The latter are MCSs sharing a contiguous rain area. Mapping of the objectively identified MCSs shows patterns of MCSs that are consistent with previous studies of tropical convection, with separated MCSs dominant over Africa and the Amazon regions and connected MCSs favored over the warm pool of the Indian and west Pacific Oceans. By separating the anvil from the raining regions of MCSs, this study leads to quantitative global maps of anvil coverage. These maps are consistent with the MCS analysis, and they lay the foundation for estimating the global radiative effects of anvil clouds. CloudSat radar data show that the modal thickness of MCS anvils is about 4--5 km. Anvils are mostly confined to within 1.5--2 times the equivalent radii of the primary rain areas of the MCSs. Over the warm pool, they may extend out to about 5 times the rain area radii. The warm ocean MCSs tend to have thicker non-raining and lightly raining anvils near the edges of their actively raining regions, indicating that anvils are generated in and spread out from the primary raining regions of the MCSs. Thicker anvils are nearly absent over continental regions.

  2. Geotechnical description and JGS engineering classification system for rock mass

    Microsoft Academic Search

    Masahiko OSADA; Akio FUNATO; Ryunoshin YOSHINAKA; Hiroshi ITO; Takashi KITAGAWA; Katsuji SASAKI; Kenji AOKI; Omer AYDAN; Shinji AKUTAGAWA; Hideo KIYA; Keizo KUWAHARA; Masahiro SETO; Soichi TANAKA; Kazuo TANI; Toshiaki MIMURO; Takayuki MORI

    2005-01-01

    This paper presents the new classification system which identifies and designates rock masses based on their fundamental engineering characteristics. The system encompasses the stepwise procedural classification with three steps and a sub-step. The first-step is to classify rock mass into two types; (1) hard rock mass and\\/or its weathered or altered rock mass, and (2) soft rock mass that is

  3. Mass loss rates of a sample of irregular and semiregular M-type AGB-variables

    NASA Astrophysics Data System (ADS)

    Olofsson, H.; González Delgado, D.; Kerschbaum, F.; Schöier, F. L.

    2002-09-01

    We have determined mass loss rates and gas expansion velocities for a sample of 69 M-type irregular (IRV 22 objects) and semiregular (SRV; 47 objects) AGB-variables using a radiative transfer code to model their circumstellar CO radio line emission. We believe that this sample is representative for the mass losing stars of this type. The (molecular hydrogen) mass loss rate distribution has a median value of 2.0 x 10-7 Msun yr-1, and a minimum of 2.0 x 10-8 Msun yr-1 and a maximum of 8 x 10-7 Msun yr-1. M-type IRVs and SRVs with a mass loss rate in excess of 5 x 10-7 Msun yr-1 must be very rare, and among these mass losing stars the number of sources with mass loss rates below a few 10-8 Msun yr-1 must be small. We find no significant difference between the IRVs and the SRVs in terms of their mass loss characteristics. Among the SRVs the mass loss rate shows no dependence on the period. Likewise the mass loss rate shows no correlation with the stellar temperature. The gas expansion velocity distribution has a median of 7.0 km s-1, and a minimum of 2.2 km s-1 and a maximum of 14.4 km s-1. No doubt, these objects sample the low gas expansion velocity end of AGB winds. The fraction of objects with low gas expansion velocities is very high, about 30% have velocities lower than 5 km s-1, and there are objects with velocities lower than 3 km s-1: V584 Aql, T Ari, BI Car, RX Lac, and L2 Pup. The mass loss rate and the gas expansion velocity correlate well, a result in line with theoretical predictions for an optically thin, dust-driven wind. In general, the model produces line profiles which acceptably fit the observed ones. An exceptional case is R Dor, where the high-quality, observed line profiles are essentially flat-topped, while the model ones are sharply double-peaked. The sample contains four sources with distinctly double-component CO line profiles, i.e., a narrow feature centered on a broader feature: EP Aqr, RV Boo, X Her, and SV Psc. We have modelled the two components separately for each star and derive mass loss rates and gas expansion velocities. We have compared the results of this M-star sample with a similar C-star sample analysed in the same way. The mass loss rate characteristics are very similar for the two samples. On the contrary, the gas expansion velocity distributions are clearly different. In particular, the number of low-velocity sources is much higher in the M-star sample. We found no example of the sharply double-peaked CO line profile, which is evidence of a large, detached CO-shell, among the M-stars. About 10% of the C-stars show this phenomenon.

  4. Mass Models of Dwarf Spheroidal Galaxies with Variable Stellar Anisotropy. I. Jeans Analysis

    E-print Network

    Mashchenko, Sergey

    2015-01-01

    Using a flexible galactic model with variable stellar velocity anisotropy, I apply the classical Jeans mass modeling approach to the five dwarf spheroidal galaxies with the largest homogeneous datasets of stellar line-of-sight velocities (between 330 and 2500 stars per galaxy) -- Carina, Fornax, Leo~I, Sculptor, and Sextans. I carry out an exhaustive model parameter search, assigning absolute probabilities to each parameter combination. My main finding is that there is a well defined radius (unique for each galaxy) where the Jeans analysis constraints on the enclosed mass are tightest, and are much better than the constraints at previously suggested radii (e.g. 300~pc). For Carina, Fornax, Leo~I, Sculptor, and Sextans the enclosed DM mass is $0.94 \\pm 0.20$ (at 410~pc), $7.1 \\pm 0.9$ (at 925~pc), $1.75 \\pm 0.20$ (at 390~pc), $2.59 \\pm 0.42$ (at 435~pc), and $2.3 \\pm 0.9$ (at 1035~pc), respectively (two-sigma uncertainties; in $10^7$~M$_\\odot$ units). Local DM density has the tightest constraints at smaller (a...

  5. The spectral type of CHS 7797 - an intriguing very low mass periodic variable in the Orion Nebula Cluster

    NASA Astrophysics Data System (ADS)

    Rodríguez-Ledesma, M. V.; Mundt, R.; Pintado, O.; Boudreault, S.; Hessman, F.; Herbst, W.

    2013-03-01

    Aims: We present the spectroscopic characterization of the unusual high-amplitude very low mass pre-main-sequence periodic variable CHS 7797. Methods: This study is based on optical medium-resolution (R = 2200) spectroscopy in the 6450 - 8600 Å range, carried out with GMOS-GEMINI -S in March 2011. Observations of CHS 7797 have been carried out at two distinct phases of the 17.8 d period, namely at maximum (I ? 17.4 mag) and four days before maximum (I ? 18.5 mag). Four different spectral indices were used for the spectral classification at these two phases, all of them well-suited for spectral classification of young and obscured late M dwarfs. In addition, the gravity-sensitive Na I (8183/8195 Å) and K I (7665/7699 Å) doublet lines were used to confirm the young age of CHS 7797. Results: From the spectrum obtained at maximum light we derived a spectral type (SpT) of M 6.05 ± 0.25, while for the spectrum taken four days before maximum the derived SpT is M 5.75 ± 0.25. The derived SpTs confirm that CHS 7797 has a mass in the stellar-substellar boundary mass range. In addition, the small differences in the derived SpTs at the two observed phases may provide indirect hints that CHS 7797 is a binary system of similar mass components surrounded by a tilted circumbinary disk, a system similar to KH 15D.

  6. Mass data acquisition systems in JT-60 data processing system

    NASA Astrophysics Data System (ADS)

    Oshima, T.; Matsuda, T.; Tsugita, T.; Sakata, S.; Sato, M.; Koiwa, M.

    2001-01-01

    In the data processing system for the JT-60 tokamak, a unique mass data acquisition system with fast sampling, a transient mass data storage system (TMDS), has been used since 1988. It is composed of a minicomputer and 61 channels of 4/6 MB memory modules with a sampling rate up to 200 kHz and about 300 MB of data are transferred to a main computer by using a special LAN developed by Fujitsu Ltd. TMDS can handle a large amount of data, but cannot be enlarged in its capability, such as CPU power or the number of channels. To solve the problems of TMDS, a new fast VME data acquisition system (FDS), has been developed. It can acquire 6 MB of data per channel with a sampling rate of 200 kHz or 1 MHz and consists of a workstation with VMEbus memory modules. Up to now there are three FDSs with 24 channels. The minicomputer of TMDS has been replaced with a new system based on the technology of FDS. To cope with mass data transfer to a data server, they are connected with a gigabit ethernet switch.

  7. Variable radio emission from the 4 Draconis system

    NASA Technical Reports Server (NTRS)

    Brown, Alexander

    1987-01-01

    The 4 Dra system, which contains an M3 giant and a cataclysmic binary, has been detected as a 6 cm radio source with the VLA. This radio emission is variable on time scales of weeks to months. A number of possible sources of the radio emission within the 4 Dra system are considered, and the observed time variability probably rules out optically thick free-free emission from the wind of the M3 giant as the dominant source. The major source of the observed radio emission is likely to be either the cataclysmic binary or shocked regions due to the interaction between the cataclysmic binary and the red giant wind.

  8. Solving Systems of Linear Equations in Two Variables

    NSDL National Science Digital Library

    Kim Seward

    2008-01-01

    This tutorial shows students how to solve systems of linear equations in two variables using three methods: graphing, substitution, and elimination. Each method is clearly demonstrated with graphics when applicable and step-by-step instructions so students can follow along easily. In addition, links to previously-covered algebra material are embedded in the page in case students need to review prerequisite knowledge such as solving linear equations in one variable and graphing equations. The lesson is followed by three practice problems for students to tackle using each of the three methods of solving systems of linear equations.

  9. Assesssing Variability of Dusty Galactic and Magellanic WRs and Seeking MIR Mass-Loss Nebulae

    NASA Astrophysics Data System (ADS)

    Cohen, Martin

    Wolf-Rayet (WR) stars are rare high-mass stars with potent winds which disturb and chemically enrich their surroundings, often creating optical nebulae as their ejecta sweep up the local interstellar medium. The intriguing dusty late-type carbon WRs) have generated thick circumstellar shells. Many WCs often have variable dust production, some periodic, others random. Only by studying all these highly energetic stars in depth will we decipher the nature of the dust condensation process and the pathway to grains in these hydrogen-poor atmospheres. This promises an accurate assessment of the quantitative contribution of WRs to the cosmic carbon budget. Such stars are few in number, but play a key role in generating the chemical elements and recycling stellar material. In 2001 we knew 227 Galactic WRs and 99% of the WC9s were dusty. Today we list close to 400 WR including the the WN and WO types. But only 56% of the WC9s are known to be dusty, dominated by those with persistent dust. Those for which we have determined both the existence of dust variability and know its temporal character is still of order 10. Much work remains to characterize the nature and variability of IR emission for many newly discovered WCs which have only optical classifications. Every new IR survey of the Galactic plane has the potential to offer crucial data on dusty WR stars, by finding new examples or providing another epoch of photometry for previously known WCs, to compare with earlier IR data to study the individual mass loss history for each. This is the method by which these variable stars were found to undergo episodes of dust making and it maximizes the value of old data sets, particularly when the effort is made to maintain a consistent absolute calibration for new missions. It is not enough merely to uncover new WCs, nor even to assign spectral classes to them. It is also essential to archive their spectral energy distributions (SEDs) as fiducial references for the future. Spitzer offers a wealth of new measurements of known WRs and it has already contributed substantially to the increase in the current census of Galactic WRs. WRs are often associated with optical so-called "ring nebulae" which are essentially fossil records of stellar mass loss. Spitzer has observed, and is currently still observing, large areas of the Galactic plane. It is timely to undertake an unbiased survey of WRs looking for new, small, faint 5-20 micron counterparts, particularly for the WC and WO stars which,combined, are a factor of two less frequently allied with ring nebulae than are WN stars. My specific objectives are to: (i) develop IR SEDs for as many as possible of the known WR stars in the Galaxy and in the Magellanic Clouds; (ii) quantify any IR excess over the combination of photosphere, wind, and free-free emission; (iii) determine whether each excess is due to free-free or thermal emission of warm dust grains and, for dust, measure the temperature; (iv) decide from all available IR photometry of a WC star at different epochs whether this dust emission is variable or constant; (v) create a repository of reference SEDs of all dusty WC stars, in particular, so that future observations may be compared with these benchmarks; (vi) seek new dusty WRs in those regions of the Galactic plane that are still being surveyed by Spitzer; (vii) examine Spitzer images of all known Galactic and Magellanic WRs seeking unknown, potentially associated, MIR nebulae; (viii) measure spatially integrated nebular SEDs; (ix) test whether these nebulae are thermal radio emitters and, if so, determine their IRAC/MIPS color indices, false colors and MIR/radio flux ratios as potential discriminants for WR nebulae among the many kinds of bubble in the ISM.

  10. Interannual salinity variability of the Northern Yellow Sea Cold Water Mass

    NASA Astrophysics Data System (ADS)

    Li, Ang; Yu, Fei; Diao, Xinyuan

    2015-05-01

    This paper discusses the interannual variability of the Northern Yellow Sea Cold Water Mass (NYSCWM) and the factors that influence it, based on survey data from the 1976-2006 national standard section and the Korea Oceanographic Data Center, monthly E-P flux data from the European Centre for Medium-Range Weather Forecasts, and meridional wind speed data from the International Comprehensive Ocean-Atmosphere Data Set. The results show that: 1) the mean salinity of the NYSCWM center has a slightly decreasing trend, which is not consistent with the high salinity center; 2) both the southern salinity front and the halocline of the NYSCWM display a weakening trend, which indicates that the difference between the NYSCWM and coastal water decreases; 3) the Yellow Sea Warm Current intrusion, the E-P flux of the northern Yellow Sea, and the strength of the winter monsoon will affect the NYSCWM salinity during the following summer.

  11. Effect of spatially variable effective mass on static and dynamic properties of resonant tunneling devices

    NASA Astrophysics Data System (ADS)

    Mains, R. K.; Mehdi, I.; Haddad, G. I.

    1989-12-01

    The effect of incorporating a spatially variable effective mass in the Schroedinger equation method of resonant tunneling device modeling is investigated. It is shown that inclusion of this effect can produce an order of magnitude difference in the calculated peak current density of the static current-voltage (I-V) curve for the resonant tunneling diode. Results for a particular In(0.53)Ga(0.47)As-AlAs structure show that much better agreement between theory and experiment is obtained by including this effect. Also, comparison of transient results for an In(0.53)Ga(0.47)As-In(0.52)Al(0.48)As structure shows a significant change in the diode switching transients.

  12. Vibration isolation and reduction by spring-stiffness control based on theory of variable structure systems

    SciTech Connect

    Yamaguchi, H.; Shioya, S. [National Defense Academy, Yokosuka (Japan). Dept. of Mechanical Engineering; Oda, M. [National Defense Agency, Gotenba (Japan)

    1995-12-31

    By controlling spring stiffness, vibration reduction and isolation for the mass-spring system are achieved in this paper. The control algorithm of the spring stiffness is based on the variable structure systems (VSS) theory. The stiffness-controllable spring is achieved by using two straight bars that are hinged to the mass in a line perpendicular to the direction of mass motion and are applied axial force. Since the axial force causes restoring force equivalent to the spring, the stiffness is controlled by the axial force. In the numerical simulations and experiments, the settling time of the impulse response and the displacement transmissibility are investigated. The results show that the proposed method is effective in suppressing shock motion and isolating vibration transmitted from the floor.

  13. The evolution of low-mass close binary systems with a compact component. II - Systems captured by angular momentum losses

    NASA Astrophysics Data System (ADS)

    Pylyser, E. H. P.; Savonije, G. J.

    1989-01-01

    The paper presents numerical calculations simulating the evolution of low-mass, interacting close binary systems in which mass-exchange is started from a 1.0-2.0 solar mass-losing component towards an accreting compact companion. The range of initial periods of these systems has been chosen to: (1) result in the capture of the system by angular momentum losses, and (2) cover a large part of the possible evolutionary paths of short-period cataclysmic variables and low-mass X-ray binary systems. Such an investigation extends the initial donor star mass to higher values than in previous similar studies. The systemic characteristics at different evolutionary stages of the mass exchange phase are in good agreement with results obtained in previous work. It is argued that the observed spread in mass transfer rates for a given orbital period is, by means of the process of magnetic braking, largely related to the spread in the moments of inertia of the mass-losing component in these systems. This reflects the natural distribution of initial periods (after termination of the spiral-in phase) of their progenitor systems.

  14. Water mass variability in the Atlantic Subtropical Gyre reveals the mechanisms of recent Meridional Overturning changes

    NASA Astrophysics Data System (ADS)

    Gwyn Evans, Dafydd; Toole, John; Forget, Gael; Zika, Jan; Nurser, A. George; Naveira Garabato, Alberto; Yu, Lisan

    2015-04-01

    Interannual variability in the volumetric water-mass distribution within the North Atlantic subtropical gyre (STG) is described in relation to the recent reported changes in the Atlantic Meridional Overturning Circulation (AMOC). Using an Argo based gridded climatology and a high-resolution ocean state estimate (ECCO), we project the ocean into thermohaline coordinates as volumes of water defined by their temperature and salinity. We compare monthly time-series of the volumetric distribution to the volume changes implied by the water mass transformations due to air/sea fluxes of heat and freshwater over the STG, and the divergence of advective transports across the latitudinal boundaries of the STG. Coinciding with the reported AMOC changes during the winters of 2009/10 and 2010/11, in both the observations and the state estimate, the total STG volume above the thermocline decreases while the volume below increases in compensation. During the winter of 2009/10, this redistribution is equivalent to a transport of 25 Sv (1 Sv==106 m3s-1) over 3 months. A comparison to two air-sea flux re-analyses products shows that this variability cannot be explained by anomalous cooling over the STG, which suggests the volumetric redistribution is caused by changes in the transport divergence between 26 and 45°N. In ECCO, we see a reduction in the zonal circulation of the STG and divergence of transport above the thermocline. Below the thermocline we see an increase in the southward transport at 45°N and a decrease at 26°N. Using two wind-stress products, we present evidence that the observed changes are a barotropic response to anomalous wind-stress curl over the STG.

  15. Mass Uncertainty and Application For Space Systems

    NASA Technical Reports Server (NTRS)

    Beech, Geoffrey

    2013-01-01

    Expected development maturity under contract (spec) should correlate with Project/Program Approved MGA Depletion Schedule in Mass Properties Control Plan. If specification NTE, MGA is inclusive of Actual MGA (A5 & A6). If specification is not an NTE Actual MGA (e.g. nominal), then MGA values are reduced by A5 values and A5 is representative of remaining uncertainty. Basic Mass = Engineering Estimate based on design and construction principles with NO embedded margin MGA Mass = Basic Mass * assessed % from approved MGA schedule. Predicted Mass = Basic + MGA. Aggregate MGA % = (Aggregate Predicted - Aggregate Basic) /Aggregate Basic.

  16. Mass spectrometric investigation of molecular variability of grass pollen group 1 allergens.

    PubMed

    Fenaille, François; Nony, Emmanuel; Chabre, Henri; Lautrette, Aurélie; Couret, Marie-Noëlle; Batard, Thierry; Moingeon, Philippe; Ezan, Eric

    2009-08-01

    Natural grass pollen allergens exhibit a wide variety of isoforms. Precise characterization of such microheterogeneity is essential to improve diagnosis and design appropriate immunotherapies. Moreover, standardization of allergen vaccine production is a prerequisite for product safety and efficiency. Both qualitative and quantitative analytical methods are thus required to monitor and control the huge natural variability of pollens, as well as final product quality. A proteomic approach has been set up to investigate in depth the structural variability of five group 1 allergens originating from distinct grass species (Ant o 1, Dac g 1, Lol p 1, Phl p 1, and Poa p 1). Whereas group 1 is the most conserved grass pollen allergen, great variations were shown between the various isoforms found in these five species using mass spectrometry, with many amino acid exchanges, as well as variations in proline hydroxylation level and in main N-glycan motifs. The presence of O-linked pentose residues was also demonstrated, with up to three consecutive units on the first hydroxyproline of Ant o 1. In addition, species-specific peptides were identified that might be used for product authentication or individual allergen quantification. Lastly, natural or process-induced modifications (deamidation, oxidation, glycation) were evidenced, which might constitute useful indicators of product degradation. PMID:19572759

  17. Modelling the variability of complex systems by means of Langevin

    E-print Network

    Peinke, Joachim

    Modelling the variability of complex systems by means of Langevin processes On the application . . . . . . . . . . . . . . . . 1 1.2 Reconstructing the dynamics of Langevin processes . . . . . . . . . . 3 1.3 Stochastic modelling of experimental data . . . . . . . . . . . . . . . 5 1.4 Extension to Langevin-like processes

  18. Baselining illumination variables for improved facial recognition system performance

    Microsoft Academic Search

    Brett A McLindin

    2003-01-01

    Lighting has been shown to be one of the largest degradation factors of facial recognition systems. Several model and algorithmic approaches have been attempted to reduce this problem with varying success. We present here results from an experimental program which quantifies lighting variables including direction, temperature and colour, intensity, diffuseness and glare, as tested on the face-it and SQIS facial

  19. Extremal entanglement and mixedness in continuous variable systems

    Microsoft Academic Search

    Gerardo Adesso; Alessio Serafini; Fabrizio Illuminati

    2004-01-01

    We investigate the relationship between mixedness and entanglement for Gaussian states of continuous variable systems. We introduce generalized entropies based on Schatten p norms to quantify the mixedness of a state and derive their explicit expressions in terms of symplectic spectra. We compare the hierarchies of mixedness provided by such measures with the one provided by the purity (defined as

  20. Quantification and Scaling of Multipartite Entanglement in Continuous Variable Systems

    Microsoft Academic Search

    Gerardo Adesso; Alessio Serafini; Fabrizio Illuminati

    2004-01-01

    We present a theoretical method to determine the multipartite entanglement between different partitions of multimode, fully or partially symmetric Gaussian states of continuous variable systems. For such states, we determine the exact expression of the logarithmic negativity and show that it coincides with that of equivalent two-mode Gaussian states. Exploiting this reduction, we demonstrate the scaling of the multipartite entanglement

  1. How does variability of immune system genes affect placentation?

    Microsoft Academic Search

    F. Colucci; S. Boulenouar; J. Kieckbusch; A. Moffett

    2011-01-01

    Formation of the placenta is a crucial step in mammalian pregnancy. Apart from its function in ensuring an optimal supply of nutrients and oxygen to the fetus, the placenta is also the interface at which allo-recognition of invading trophoblast cells by the maternal immune system can potentially occur. We summarise here the “state of the art” on how variability of

  2. Hydraulic line pressure control system for an infinitely variable transmission

    Microsoft Academic Search

    1987-01-01

    An improved control system is described for an infinitely variable transmission for transmitting the power of an internal combustion engine mounted on a vehicle. The transmission comprises: a primary pulley having a hydraulically shiftable disc and a hydraulic cylinder for shifting the disc, a secondary pulley having a hydraulically shiftable disc and a hydraulic cylinder for operating the disc, a

  3. Regulator valve for hydraulic control system including variable displacement pump

    Microsoft Academic Search

    T. Shibayama; K. Sugano

    1986-01-01

    A hydraulic control system is described for an automotive automatic transmission comprising: an automatic transmission actuated by hydraulic fluid; a variable capacity pump for supplying hydraulic fluid under pressure for actuating the automatic transmission. The pump has a control arrangement including a control chamber which varies the capacity of the pump in response to the pressure prevailing therein. A pressure

  4. Direct measurement of sub-surface mass change using the variable-baseline gravity gradient method

    USGS Publications Warehouse

    Kennedy, Jeffrey; Ferré, Ty P. A.; Güntner, Andreas; Abe, Maiko; Creutzfeldt, Benjamin

    2014-01-01

    Time-lapse gravity data provide a direct, non-destructive method to monitor mass changes at scales from cm to km. But, the effectively infinite spatial sensitivity of gravity measurements can make it difficult to isolate the signal of interest. The variable-baseline gravity gradient method, based on the difference of measurements between two gravimeters, is an alternative to the conventional approach of individually modeling all sources of mass and elevation change. This approach can improve the signal-to-noise ratio for many applications by removing the contributions of Earth tides, loading, and other signals that have the same effect on both gravimeters. At the same time, this approach can focus the support volume within a relatively small user-defined region of the subsurface. The method is demonstrated using paired superconducting gravimeters to make for the first time a large-scale, non-invasive measurement of infiltration wetting front velocity and change in water content above the wetting front.

  5. Time-Variable Gravity Signal Due to Extratropic Pacific Water Mass Redistribution

    NASA Technical Reports Server (NTRS)

    Chao, Benjamin F.; Au, A. Y.; Cox, C. M.

    2002-01-01

    Cox and Chao [2002] reported the detection of a large anomaly in the form of a positive "jump" in the time series of Earth's lowest-degree gravity harmonic J2, or the dynamic oblateness, during 1998. This prompted us to examine the mass redistribution in the global oceans. We report here a seesaw of the sea-surface height (SSH) in the extratropic north + south Pacific basins -- the leading (nonseasonal) EOF/PC mode in SSH derived from the 10-year TOPEX/Poseidon altimetry data in the extratropic Pacific region. The mode underwent a step-like jump with time evolution that match remarkably well with the observed J2 anomaly. However, the magnitude is several times too small to explain the observed J2, even if assuming the SSH jump was all mass-induced (as opposed to any steric effect which causes no time-variable gravity signal). If one accepts the notion that this extratropic Pacific seesaw is part of the geophysical process that produced the observed 1998 J2 anomaly, then this finding suggests strong geophysical connection of the interannual-to-decadal variation of J2 with the Pacific Decadal Oscillation (PDO), as the time series of the above EOF/PC mode is actually a formally defined PDO Index series.

  6. Vital role of daily temperature variability in surface mass balance parameterizations of the Greenland Ice Sheet

    NASA Astrophysics Data System (ADS)

    Rogozhina, I.; Rau, D.

    2014-04-01

    This study aims to demonstrate that the spatial and seasonal effects of daily temperature variability in positive degree-day (PDD) models play a decisive role in shaping the modeled surface mass balance (SMB) of continental-scale ice masses. Here we derive monthly fields of daily temperature standard deviation (SD) across Greenland from the ERA-40 (European Centre for Medium-Range Weather Forecasts 40 yr Reanalysis) reanalysis spanning from 1958 to 2001 and apply these fields to model recent surface responses of the Greenland Ice Sheet (GIS). Neither the climate data set analyzed nor in situ measurements taken in Greenland support the range of commonly used spatially and temporally uniform SD values (~ 5 °C). In this region, the SD distribution is highly inhomogeneous and characterized by low values during summer months (~ 1 to 2.5 °C) in areas where most surface melting occurs. As a result, existing SMB parameterizations using uniform, high SD values fail to capture both the spatial pattern and amplitude of the observed surface responses of the GIS. Using realistic SD values enables significant improvements in the modeled regional and total SMB with respect to existing estimates from recent satellite observations and the results of a high-resolution regional model. In addition, this resolves large uncertainties associated with other major parameters of a PDD model, namely degree-day factors. The model appears to be nearly insensitive to the choice of degree-day factors after adopting the realistic SD distribution.

  7. Variable-magnification system in a microscope illuminator

    NASA Astrophysics Data System (ADS)

    Vinogradova, O. A.; Zverev, V. A.; Tochilina, T. V.; Ramin, K.

    2006-10-01

    The efficiency with which the light flux is utilized in a microscope's optical system is determined by how well the exit numerical aperture and the linear field of the condenser are matched with the numerical aperture and linear field of the microscope lens. It is shown that using a variable-magnification system in the layout of a microscope illuminator makes it possible to increase the efficiency with which the light flux is utilized by a factor of more than a hundred.

  8. Dynamical Constraints on the Component Masses of the Cataclysmic Variable WZ Sagittae

    NASA Astrophysics Data System (ADS)

    Steeghs, Danny; Howell, Steve B.; Knigge, Christian; Gänsicke, Boris T.; Sion, Edward M.; Welsh, William F.

    2007-09-01

    We present phase-resolved spectroscopy of the short-period cataclysmic variable WZ Sge obtained with the Hubble Space Telescope. We were able to resolve the orbital motion of a number of absorption lines that likely probe the environment near the accreting white dwarf. The radial velocities derived from simultaneous fits to 13 absorption lines indicate an orbital velocity semi-amplitude of KUV=(47+/-3) km s-1. However, we find that the phase zero is offset from the white dwarf ephemeris by +0.1. Our offset and velocity amplitude are very similar to constraints derived from optical emission lines from the quiescent accretion disk, despite the fact that we are probing material much closer to the primary. If we associate the UV amplitude with K1, our dynamical constraints together with the published K2 estimates and the known binary inclination of i=77+/-2 imply 0.88 Msolarmass of the primary of M1=(0.85+/-0.04) Msolar when coupled with a mass-radius relation. Our primary mass estimates are in excellent agreement and are also self-consistent with spectrophotometric fits to the UV fluxes despite the observed phase offset. It is at this point unclear what causes the observed phase offset in the UV spectra and by how much it distorts the radial velocity signature from the underlying white dwarf.

  9. Synchronization between variable time delayed systems and cryptography

    E-print Network

    Dibakar Ghosh; Santo Banerjee; A. Roy Chowdhury

    2008-02-06

    In this letter we consider a prototype model which is described as an autonomous continuous time delayed differential equation with just one variable. The chaos has been investigated with variable delay time and the synchronization phenomenon is examined both numerically and analytically using the Krasovskii-Lyapunov functions. We have applied adaptive coupling law for synchronization,where the coupling equation also contains delay with modulated time. We also studied the effect of cryptography for this coupled system and the message extraction procedure is illustrated with the help of simulated results.

  10. Development and characterization of a variable turbulence generation system

    NASA Astrophysics Data System (ADS)

    Marshall, A.; Venkateswaran, P.; Noble, D.; Seitzman, J.; Lieuwen, T.

    2011-09-01

    Experimental turbulent combustion studies require systems that can simulate the turbulence intensities [ u'/ U 0 ~ 20-30% (Koutmos and McGuirk in Exp Fluids 7(5):344-354, 1989)] and operating conditions of real systems. Furthermore, it is important to have systems where turbulence intensity can be varied independently of mean flow velocity, as quantities such as turbulent flame speed and turbulent flame brush thickness exhibit complex and not yet fully understood dependencies upon both U 0 and u'. Finally, high pressure operation in a highly pre-heated environment requires systems that can be sealed, withstand high gas temperatures, and have remotely variable turbulence intensity that does not require system shut down and disassembly. This paper describes the development and characterization of a variable turbulence generation system for turbulent combustion studies. The system is capable of a wide range of turbulence intensities (10-30%) and turbulent Reynolds numbers (140-2,200) over a range of flow velocities. An important aspect of this system is the ability to vary the turbulence intensity remotely, without changing the mean flow velocity. This system is similar to the turbulence generators described by Videto and Santavicca (Combust Sci Technol 76(1):159-164, 1991) and Coppola and Gomez (Exp Therm Fluid Sci 33(7):1037-1048, 2009), where variable blockage ratio slots are located upstream of a contoured nozzle. Vortical structures from the slots impinge on the walls of the contoured nozzle to produce fine-scale turbulence. The flow field was characterized for two nozzle diameters using three-component Laser Doppler velocimetry (LDV) and hotwire anemometry for mean flow velocities from 4 to 50 m/s. This paper describes the key design features of the system, as well as the variation of mean and RMS velocity, integral length scales, and spectra with nozzle diameter, flow velocity, and turbulence generator blockage ratio.

  11. Dramatic variability of the carbonate system of the coastal ocean is regulated by physical and biogeochemical processes on multiple timescales

    NASA Astrophysics Data System (ADS)

    Johnson, Z. I.; Hunt, D.

    2013-12-01

    Increased atmospheric carbon dioxide (CO2) from anthropogenic sources is acidifying marine environments with potentially dramatic implications for the physical, chemical and biological functioning of these ecosystems. If current trends continue, mean ocean pH is expected to decrease by ~0.2 units over the next ~50 years. Yet, at the same time there is substantial spatial and temporal variability in pH and other carbon system parameters in the ocean resulting in regions that already exceed long term projected pH changes, suggesting that short-term variability is an important layer of complexity on top of long term acidification. Thus, in order to develop predictions of future climate change impacts including ocean acidification, there is a critical need to characterize the natural range and variability of the marine CO2 system and the mechanisms responsible for this variability. Here we examine pH and dissolved inorganic carbon (DIC) variability at time intervals spanning 1 hour to >1 year in a dynamic coastal marine system to quantify variability of the carbon system at multiple time scales. Daily and seasonal variability of the carbon system is largely driven by temperature, alkalinity and the balance between primary production and respiration, but high frequency variability (hours to days) is further influenced by water mass movement (e.g. tides) and stochastic events (e.g. storms). Both annual variability (~0.3 units) and diurnal variability (~0.1 units) in coastal ocean acidity are similar in magnitude to long term projections associated with increasing atmospheric CO2 and their drivers highlight the importance of characterizing the complete carbonate system (and not just pH). Short term variability of ocean carbon parameters may already exert significant pressure on some coastal marine ecosystems with implications for ecology, biogeochemistry and evolution and this shorter term variability layers additive effects and complexity, including extreme values, on top of long term trends in ocean acidification.

  12. Earth System Science Education Centered on Natural Climate Variability

    NASA Astrophysics Data System (ADS)

    Ramirez, P. C.; Ladochy, S.; Patzert, W. C.; Willis, J. K.

    2009-12-01

    Several new courses and many educational activities related to climate change are available to teachers and students of all grade levels. However, not all new discoveries in climate research have reached the science education community. In particular, effective learning tools explaining natural climate change are scarce. For example, the Pacific Decadal Oscillation (PDO) is a main cause of natural climate variability spanning decades. While most educators are familiar with the shorter-temporal events impacting climate, El Niño and La Niña, very little has trickled into the climate change curriculum on the PDO. We have developed two online educational modules, using an Earth system science approach, on the PDO and its role in climate change and variability. The first concentrates on the discovery of the PDO through records of salmon catch in the Pacific Northwest and Alaska. We present the connection between salmon abundance in the North Pacific to changing sea surface temperature patterns associated with the PDO. The connection between sea surface temperatures and salmon abundance led to the discovery of the PDO. Our activity also lets students explore the role of salmon in the economy and culture of the Pacific Northwest and Alaska and the environmental requirements for salmon survival. The second module is based on the climate of southern California and how changes in the Pacific Ocean , such as the PDO and ENSO (El Niño-Southern Oscillation), influence regional climate variability. PDO and ENSO signals are evident in the long-term temperature and precipitation record of southern California. Students are guided in the module to discover the relationships between Pacific Ocean conditions and southern California climate variability. The module also provides information establishing the relationship between climate change and variability and the state's water, energy, agriculture, wildfires and forestry, air quality and health issues. Both modules will be reviewed for inclusion on the ESSEA (Earth Systems Science Education Alliance) course module list. ESSEA is a NSF-funded organization dedicated to K-12 online Earth system science education.

  13. The genetic and environmental sources of body mass index variability: the Muscatine Ponderosity Family Study.

    PubMed Central

    Moll, P P; Burns, T L; Lauer, R M

    1991-01-01

    The role of genetic and environmental factors in determining the variability in body mass index (BMI; kg/m2) was investigated in 1,302 relatives identified through 284 schoolchildren from Muscatine, IA. BMI levels were first adjusted for variability in age, by gender and by relative type. There was significant familial aggregation of adjusted BMI in the pedigrees, as indicated by inter- and intraclass correlation coefficients significantly different from zero. A mixture of two normal distributions fit the adjusted BMI data better than did a single normal distribution. Genetic and environmental models that could explain both the familial aggregation and the mixture of normal distributions were investigated using complex segregation analysis. There was strong support for a single recessive locus with a major effect that accounted for almost 35% of the adjusted variation in BMI. Polygenic loci accounted for an additional 42% of the variation. Approximately 23% of the adjusted variation was not explained by genetic factors. For spouses living in the same household, their shared environment accounted for 12% of their variation. For siblings living in the same household, their shared environment accounted for 10% of their variation. While shared environments contributed to variation in adjusted BMI, more than 75% of the variation was explained by genetic factors that include a single recessive locus. Approximately 6% of the individuals in the population from which these pedigrees were sampled are predicted to have two copies of the recessive gene, while 37% of the individuals are predicted to have one copy of the gene. PMID:1746554

  14. The evolution of low-mass close binary systems. IV - 0.80 solar mass + 0.40 solar mass - Catastrophic mass loss

    Microsoft Academic Search

    R. F. Webbink

    1977-01-01

    The evolution of both components of a 0.80 + 0.40 solar mass binary with initial separation of 1.60 solar radii is presented. This system reaches mass transfer during core hydrogen burning in the primary. The primary has such a deep convective envelope that mass transfer proceeds on a dynamical time scale. Mass exchange is followed through the first 0.00625 solar

  15. Variable structure control design for uncertain discrete-time systems

    Microsoft Academic Search

    Wen-June Wang; Gin-Hol Wu; Dah-Ching Yang

    1994-01-01

    The main differences between the designs of discrete-time variable structure systems (VSS) and continuous-time VSS are the determination of the switching hyperplane and the satisfaction of the hitting\\/sliding condition. These differences yield many difficulties in the design of sliding mode control for the discrete-time VSS. This note tries to overcome these difficulties and design a simple sliding mode control for

  16. Quantification and scaling of multipartite entanglement in continuous variable systems.

    PubMed

    Adesso, Gerardo; Serafini, Alessio; Illuminati, Fabrizio

    2004-11-26

    We present a theoretical method to determine the multipartite entanglement between different partitions of multimode, fully or partially symmetric Gaussian states of continuous variable systems. For such states, we determine the exact expression of the logarithmic negativity and show that it coincides with that of equivalent two-mode Gaussian states. Exploiting this reduction, we demonstrate the scaling of the multipartite entanglement with the number of modes and its reliable experimental estimate by direct measurements of the global and local purities. PMID:15601075

  17. Evaluation of a variable dose acquisition technique for microcalcification and mass detection in digital breast tomosynthesis

    PubMed Central

    Das, Mini; Gifford, Howard C.; O’Connor, J. Michael; Glick, Stephen J.

    2009-01-01

    In this article the authors evaluate a recently proposed variable dose (VD)-digital breast tomosynthesis (DBT) acquisition technique in terms of the detection accuracy for breast masses and microcalcification (MC) clusters. With this technique, approximately half of the total dose is used for one center projection and the remaining dose is split among the other tomosynthesis projection views. This acquisition method would yield both a projection view and a reconstruction view. One of the aims of this study was to evaluate whether the center projection alone of the VD acquisition can provide equal or superior MC detection in comparison to the 3D images from uniform dose (UD)-DBT. Another aim was to compare the mass-detection capabilities of 3D reconstructions from VD-DBT and UD-DBT. In a localization receiver operating characteristic (LROC) observer study of MC detection, the authors compared the center projection of a VD acquisition scheme (at 2 mGy dose) with detector pixel size of 100 ?m with the UD-DBT reconstruction (at 4 mGy dose) obtained with a voxel size of 100 ?m. MCs with sizes of 150 and 180 ?m were used in the study, with each cluster consisting of seven MCs distributed randomly within a small volume. Reconstructed images in UD-DBT were obtained from a projection set that had a total of 4 mGy dose. The current study shows that for MC detection, using the center projection alone of VD acquisition scheme performs worse with area under the LROC curve (AL) of 0.76 than when using the 3D reconstructed image using the UD acquisition scheme (AL=0.84). A 2D ANOVA found a statistically significant difference (p=0.038) at a significance level of 0.05. In the current study, although a reconstructed image was also available using the VD acquisition scheme, it was not used to assist the MC detection task which was done using the center projection alone. In the case of evaluation of detection accuracy of masses, the reconstruction with VD-DBT (AL=0.71) was compared to that obtained from the UD-DBT (AL=0.78). The authors found no statistically significant difference between the two (p-value=0.22), although all the observers performed better for UD-DBT. PMID:19610286

  18. Performance of Thermal Mass Flow Meters in a Variable Gravitational Environment

    NASA Technical Reports Server (NTRS)

    Brooker, John E.; Ruff, Gary A.

    2004-01-01

    The performance of five thermal mass flow meters, MKS Instruments 179A and 258C, Unit Instruments UFM-8100, Sierra Instruments 830L, and Hastings Instruments HFM-200, were tested on the KC-135 Reduced Gravity Aircraft in orthogonal, coparallel, and counterparallel orientations relative to gravity. Data was taken throughout the parabolic trajectory where the g-level varied from 0.01 to 1.8 times normal gravity. Each meter was calibrated in normal gravity in the orthogonal position prior to flight followed by ground testing at seven different flow conditions to establish a baseline operation. During the tests, the actual flow rate was measured independently using choked-flow orifices. Gravitational acceleration and attitude had a unique effect on the performance of each meter. All meters operated within acceptable limits at all gravity levels in the calibrated orthogonal position. However, when operated in other orientations, the deviations from the reference flow became substantial for several of the flow meters. Data analysis indicated that the greatest source of error was the effect of orientation, followed by the gravity level. This work emphasized that when operating thermal flow meters in a variable gravity environment, it is critical to orient the meter in the same direction relative to gravity in which it was calibrated. Unfortunately, there was no test in normal gravity that could predict the performance of a meter in reduced gravity. When operating in reduced gravity, all meters indicated within 5 percent of the full scale reading at all flow conditions and orientations.

  19. Dynamical masses of a nova-like variable on the edge of the period gap

    E-print Network

    Rodríguez-Gil, P; Marsh, T R; Gänsicke, B T; Steeghs, D; Long, K S; Martínez-Pais, I G; Padilla, M Armas; Schwarz, R; Schreiber, M R; Torres, M A P; Koester, D; Dhillon, V S; Castellano, J; Rodríguez, D

    2015-01-01

    We present the first dynamical determination of the binary parameters of an eclipsing SW Sextantis star in the 3-4 hour orbital period range during a low state. We obtained time-resolved optical spectroscopy and photometry of HS 0220+0603 during its 2004-2005 low brightness state, as revealed in the combined SMARTS, IAC80 and M1 Group long-term optical light curve. The optical spectra taken during primary eclipse reveal a secondary star spectral type of M5.5 $\\pm$ 0.5 as derived from molecular band-head indices. The spectra also provide the first detection of a DAB white dwarf in a cataclysmic variable. By modelling its optical spectrum we estimate a white dwarf temperature of 30000 $\\pm$ 5000 K. By combining the results of modelling the white dwarf eclipse from ULTRACAM light curves with those obtained by simultaneously fitting the emission- and absorption-line radial velocity curves and I-band ellipsoidal light curves, we measure the stellar masses to be M$_1 = 0.87 \\pm 0.09$ M$_\\odot$ and M$_2 = 0.47 \\pm 0...

  20. Modeling Mass in the Solar System and a Galaxy

    NSDL National Science Digital Library

    In this activity, students will discover how mass is distributed in the solar system and a galaxy by using kitty litter. Students compare the distribution of mass in a solar system to the distribution of mass in a galaxy. This is Activity 6a in the "Hiddne Lives of Galaxies" information and activity booklet. It is designed for use with "The Hidden Lives of Galaxies" poster. The activity includes a student worksheet and background information for the teacher.

  1. Glacier mass balance variability in the Cordillera Blanca, Peru and its relationship with climate and the large-scale circulation

    E-print Network

    Vuille, Mathias

    Glacier mass balance variability in the Cordillera Blanca, Peru and its relationship with climate the Cordillera Blanca, Peru, was investigated for its climate sensitivity toward temperature, humidity reserved. Keywords: Andes; glaciers; climate change; ENSO 1. Introduction Glaciers in the Andes of Peru

  2. Electrical transmission system with variable frequency through long length cable

    SciTech Connect

    Oliveira, J.C.; Andrade, D.A.; Araujo, S.C.N. [Univ. Federal de Uberlandia (Brazil); Paulsen, R.J.; Amaral, M.A. [Petrobras A/S, Rio de Janeiro (Brazil)

    1996-12-31

    In the face of its oil reserves characteristics, deep and ultra-deep exploitation have become a vital issue for Brazil. In those cases where the oil field does not have enough pressure to ensure natural oil flow from the bottom of the sea to the platform, the process will require the use of variable speed inverter-fed subsea electrical motors placed far away from the electrical energy source. This implies a new operational condition for the electric system, which is electrical energy transmission with variable frequency, through long length cable, in the subsea environment. The behavior of such systems has not yet been extensively studied, and in the face of the costs involved, careful analysis is mandatory. The paper presents a powerful simulation tool developed for the analysis of such electrical systems. The analysis is carried out in time domain. Harmonics components of voltages and currents and their effects on the system operation are analyzed. Comparison of simulated and measured results for an actual working installation is shown. Simulation results for a long length cable transmission system are discussed.

  3. Extremal entanglement and mixedness in continuous variable systems

    SciTech Connect

    Adesso, Gerardo; Serafini, Alessio; Illuminati, Fabrizio [Dipartimento di Fisica 'E. R. Caianiello', Universita di Salerno, INFM UdR di Salerno, INFN Sezione di Napoli, Gruppo Collegato di Salerno, Via S. Allende, 84081 Baronissi, SA (Italy)

    2004-08-01

    We investigate the relationship between mixedness and entanglement for Gaussian states of continuous variable systems. We introduce generalized entropies based on Schatten p norms to quantify the mixedness of a state and derive their explicit expressions in terms of symplectic spectra. We compare the hierarchies of mixedness provided by such measures with the one provided by the purity (defined as tr {rho}{sup 2} for the state {rho}) for generic n-mode states. We then review the analysis proving the existence of both maximally and minimally entangled states at given global and marginal purities, with the entanglement quantified by the logarithmic negativity. Based on these results, we extend such an analysis to generalized entropies, introducing and fully characterizing maximally and minimally entangled states for given global and local generalized entropies. We compare the different roles played by the purity and by the generalized p entropies in quantifying the entanglement and the mixedness of continuous variable systems. We introduce the concept of average logarithmic negativity, showing that it allows a reliable quantitative estimate of continuous variable entanglement by direct measurements of global and marginal generalized p entropies.

  4. Association of Body Mass Index with Depression, Anxiety and Suicide—An Instrumental Variable Analysis of the HUNT Study

    PubMed Central

    Bjørngaard, Johan Håkon; Carslake, David; Lund Nilsen, Tom Ivar; Linthorst, Astrid C. E.; Davey Smith, George; Gunnell, David; Romundstad, Pål Richard

    2015-01-01

    Objective While high body mass index is associated with an increased risk of depression and anxiety, cumulative evidence indicates that it is a protective factor for suicide. The associations from conventional observational studies of body mass index with mental health outcomes are likely to be influenced by reverse causality or confounding by ill-health. In the present study, we investigated the associations between offspring body mass index and parental anxiety, depression and suicide in order to avoid problems with reverse causality and confounding by ill-health. Methods We used data from 32,457 mother-offspring and 27,753 father-offspring pairs from the Norwegian HUNT-study. Anxiety and depression were assessed using the Hospital Anxiety and Depression Scale and suicide death from national registers. Associations between offspring and own body mass index and symptoms of anxiety and depression and suicide mortality were estimated using logistic and Cox regression. Causal effect estimates were estimated with a two sample instrument variable approach using offspring body mass index as an instrument for parental body mass index. Results Both own and offspring body mass index were positively associated with depression, while the results did not indicate any substantial association between body mass index and anxiety. Although precision was low, suicide mortality was inversely associated with own body mass index and the results from the analysis using offspring body mass index supported these results. Adjusted odds ratios per standard deviation body mass index from the instrumental variable analysis were 1.22 (95% CI: 1.05, 1.43) for depression, 1.10 (95% CI: 0.95, 1.27) for anxiety, and the instrumental variable estimated hazard ratios for suicide was 0.69 (95% CI: 0.30, 1.63). Conclusion The present study’s results indicate that suicide mortality is inversely associated with body mass index. We also found support for a positive association between body mass index and depression, but not for anxiety. PMID:26167892

  5. Calibrating the Correlation Between Black Hole Mass and X-ray Variability Amplitude: X-ray Only Black Hole Mass Estimates for Active Galactic Nuclei and Ultra-luminous X-ray Sources

    NASA Astrophysics Data System (ADS)

    Zhou, Xin-Lin; Zhang, Shuang-Nan; Wang, Ding-Xiong; Zhu, Ling

    2010-02-01

    A calibration is made for the correlation between the X-ray Variability Amplitude (XVA) and black hole (BH) mass. The correlation for 21 reverberation-mapped Active Galactic Nuclei (AGNs) appears very tight, with an intrinsic dispersion of 0.20 dex. The intrinsic dispersion of 0.27 dex can be obtained if BH masses are estimated from the stellar velocity dispersions. We further test the uncertainties of mass estimates from XVAs for objects that have been observed multiple times with good enough data quality. The results show that the XVAs derived from multiple observations change by a factor of 3. This means that BH mass uncertainty from a single observation is slightly worse than either reverberation-mapping or stellar velocity dispersion measurements; however, BH mass estimates with X-ray data only can be more accurate if the mean XVA value from more observations is used. With this calibrated relation, the BH mass and accretion rate may be determined for a large sample of AGNs with the planned International X-ray Observatory mission. Proper interpretation of the first AGN X-ray quasi-periodic oscillation (QPO), seen in the Seyfert galaxy RE J1034+396, depends on its BH mass, which is not currently known very well. Applying this relation, the BH mass of RE J1034+396 is found to be 4+3 -2 × 106 M sun. The high end of the mass range follows the relationship between the 2f 0 frequencies of high-frequency QPO and the BH masses derived from the Galactic X-ray binaries. We also calculate the high-frequency constant C = 2.37 M sun Hz-1 from 21 reverberation-mapped AGNs. As suggested by Gierli?ski et al., M BH = C/C M, where C M is the high-frequency variability derived from XVA. Given the similar shape of power-law dominated X-ray spectra in ultra-luminous X-ray sources (ULXs) and AGNs, this can be applied to BH mass estimates of ULXs. We discuss the observed QPO frequencies and BH mass estimates in the ULXs M82 X-1 and NGC 5408 X-1 and favor ULXs as intermediate mass BH systems.

  6. Estimating seasonal and interannual variability in ice mass loss using a stochastic filter and decade-long GRACE time series

    NASA Astrophysics Data System (ADS)

    Wang, L.; Davis, J. L.; Hill, E.; Tamisiea, M. E.

    2013-12-01

    Monthly gravity estimates produced by the Gravity Recovery and Climate Experiment (GRACE) satellite mission have been used to investigate the mass loss of glaciers and ice sheets. The mass loss signals have significant temporal (seasonal and interannual) as well as spatial variability. To obtain accurate estimates of present-day melting from decade-long GRACE measurements, a model that allows for variabilities in both mass loss rates and seasonal signals would seem appropriate. A stochastic filter approach enables us to estimate variable melting rates and seasonal amplitudes. However, it requires the statistical information on various signals and errors in the monthly GRACE estimates. Unfortunately, monthly GRACE gravity fields are contaminated by order-dependent correlated errors in the short-wavelength components, manifesting themselves as north-south elongated linear stripes in the map of surface mass changes. The widely used 'ad-hoc' destriping method is not able to preserve statistical information, and is thus inappropriate for the stochastic filter approach. In this study, we present decade-long mass variations estimated using a Kalman filter approach, which is designed to separate geophysical signals and correlated 'stripe' contamination in a series of GRACE monthly spherical-harmonic coefficient (SHC) estimates. This technique preserves statistical information, and thus enables us to estimate the impact on the SHC uncertainties associated with the destriping. The calculations are statistically rigorous and enable estimation of space-dependent robust uncertainties for ice melting rates. The Kalman-filter approach also provides smooth estimates of the gravity field that are devoid of stripes and that do not require smoothing. We use the newly produced gravity fields to revisit mass loss signals in the cryosphere, with an emphasis on investigating seasonal and interannual variabilities.

  7. Control of seismic-excited buildings using active variable stiffness systems

    Microsoft Academic Search

    J. N Yang; J. C. Wu; Z. Li

    1996-01-01

    It has been demonstrated that active variable stiffness (AVS) systems may be effective for response control of buildings subjected to earthquake excitations. The applications of active variable stiffness systems involve nonlinear control in which control theories for linear systems are not applicable. Based on the theory of variable structure system (VSS) or sliding mode control (SMC), control methods are presented

  8. Glacier Area and Mass Variability in the Wind River Range (Wyoming, USA): 2006 to 2012

    NASA Astrophysics Data System (ADS)

    Maloof, A.; Fang, B.; Tootle, G. A.; Lakshmi, V.; Kerr, G.

    2013-12-01

    The Wind River Range (WRR) is a continuous mountain range approximately 160 km in length in west-central Wyoming, USA. The Wind River Range is host to roughly 680 snow and ice bodies with 63 of these considered glaciers including seven of the ten largest glaciers in the American Rocky Mountains. The presence of glaciers results in meltwater contributions to streamflow during the late summer (July, August, and September - JAS) when snowmelt is decreasing, temperatures are high, precipitation is low, and irrigation demand peaks. Most studies indicate that the glaciers in the Wind River Range have been retreating since the 1850's, the approximate end of the Little Ice Age. Thus, the quantification of glacier meltwater (e.g., volume, mass) contributions to late-summer/early-fall streamflow is important given this resource is dwindling due to glacier recession. In this study, we selected glaciers in the WRR and obtained satellite products of study region. The ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) Level 1B imageries which are at 15 m spatial resolution between 2006~2012 were classified using supervised method and the glacier boundaries were extracted for tracking their changes. By combining ASTER L1B imageries of different years with two remote sensing derived DEM (Digital Elevation Model) datasets: ASTER GDEM (ASTER Global Digital Elevation), which is at 30 m spatial resolution and acquired prior to 2006 and Global Multi-resolution Terrain Elevation Data (GMTED 2010) which is at 250 m, 500 m and 1 km, and acquired in 2010, the 3D-view glacier volumetric loss extent could also be mapped and quantified. Assessing glacier area and volume variability is very important for evaluating and predicting glacier change in response to a changing environment.

  9. Updating Esa's Earth System Model of the Time-Variable Gravity Field for Future Mission Simulation Studies

    NASA Astrophysics Data System (ADS)

    Dobslaw, H.; Bergmann-Wolf, I.; Dill, R.; Klemann, V.; Kusche, J.; Sasgen, I.; Thomas, M.

    2014-12-01

    The ability of any satellite gravity mission concept to monitor mass transport processes in the Earth system is typically tested well ahead of its implementation by means of detailed simulation studies. Those studies often extend from the simulation of realistic orbits and instrumental data all the way down to the retrieval of global gravity field solution time-series, thereby requiring realistic representations of the spatio-temporal mass variability in the different sub-systems of the Earth as a source model for the orbit computations. For such simulations, a suitable source model is required to (i) represent rapid mass motions in for example the atmosphere and oceans, in order to realistically include the effects of temporal aliasing due to non-tidal high-frequency mass variability into the retrieved gravity fields. Moreover, (ii) low-frequency variability needs to present at realistic amplitudes and frequencies at in particular small spatial scales, in order to assess to what extent a new mission concept might provide further insight into physical processes not observed by a satellite system before. The new source model presented in this study attempts to fulfill both requirements: Based on ECMWF's recent atmospheric reanalysis ERA Interim and corresponding simulations from numerical models of the other Earth system components, it offers spherical harmonic coefficients of the mass variability in atmosphere, oceans, the terrestrial hydrosphere including the ice-sheets and glaciers, as well as the solid Earth with high temporal (6 hours) and spatial (d/o 180) resolution for a period of 12 years. Together with the source model, a corresponding de-aliasing model for atmospheric and oceanic high-frequency variability that is augmented by realistic errors is available for the gravity field retrieval process. Several features of this new dataset will be highlighted in this presentation in order to provide guidance for its application in upcoming future mission simulation studies.

  10. Design of a variable-focal-length optical system

    NASA Technical Reports Server (NTRS)

    Ricks, D.; Shannon, R. R.

    1984-01-01

    Requirements to place an entire optical system with a variable focal length ranging from 20 to 200 cm within a overall length somewhat less than 100 cm placed severe restrictions on the design of a zoom lens suitable for use on a comet explorer. The requirements of a wavelength range of 0.4 to 1.0 microns produced even greater limitations on the possibilities for a design that included a catadioptric (using mirrors and glass) front and followed by a zooming refractive portion. Capabilities available commercial zoom lenses as well as patents of optical systems are reviewed. Preliminary designs of the refractive optics zoom lens and the catadioptric system are presented and evaluated. Of the two, the latter probably has the best chance of success, so long as the shortest focal lengths are not really needed.

  11. VX Her: Eclipsing Binary System or Single Variable Star

    NASA Astrophysics Data System (ADS)

    Perry, Kathleen; Castelaz, Michael; Henson, Gary; Boghozian, Andrew

    2015-01-01

    VX Her is a pulsating variable star with a period of .4556504 days. It is believed to be part of an eclipsing binary system (Fitch et al. 1966). This hypothesis originated from Fitch seeing VX Her's minimum point on its light curve reaching a 0.7 magnitude fainter than normal and remaining that way for nearly two hours. If VX Her were indeed a binary system, I would expect to see similar results with a fainter minimum and a broader, more horizontal dip. Having reduced and analyzed images from the Southeastern Association for Research in Astronomy Observatory in Chile and Kitt Peak, as well as images from a 0.15m reflector at East Tennessee State University, I found that VX Her has the standard light curve of the prototype variable star, RR Lyrae. Using photometry, I found no differing features in its light curve to suggest that it is indeed a binary system. However, more observations are needed in case VX Her is a wide binary.

  12. An extrasolar planetary system with three Neptune-mass planets

    Microsoft Academic Search

    Christophe Lovis; Michel Mayor; Francesco Pepe; Yann Alibert; Willy Benz; François Bouchy; Alexandre C. M. Correia; Jacques Laskar; Christoph Mordasini; Didier Queloz; Nuno C. Santos; Stéphane Udry; Jean-Loup Bertaux; Jean-Pierre Sivan

    2006-01-01

    Over the past two years, the search for low-mass extrasolar planets has led to the detection of seven so-called `hot Neptunes' or `super-Earths' around Sun-like stars. These planets have masses 5-20 times larger than the Earth and are mainly found on close-in orbits with periods of 2-15days. Here we report a system of three Neptune-mass planets with periods of 8.67,

  13. Low-Mass Inflation Systems for Inflatable Structures

    NASA Technical Reports Server (NTRS)

    Thunnissen, Daniel P.; Webster, Mark S.; Engelbrecht, Carl S.

    1995-01-01

    The use of inflatable space structures has often been proposed for aerospace and planetary applications. Communication, power generation, and very-long-baseline interferometry are just three potential applications of inflatable technology. The success of inflatable structures depends on the development of an applications of inflatable technology. This paper describes two design studies performed to develop a low mass inflation system. The first study takes advantage of existing onboard propulsion gases to reduce the overall system mass. The second study assumes that there is no onboard propulsion system. Both studies employ advanced components developed for the Pluto fast flyby spacecraft to further reduce mass. The study examined four different types of systems: hydrazine, nitrogen and water, nitrogen, and xenon. This study shows that all of these systems can be built for a small space structure with masses lower than 0.5 kilograms.

  14. Compressive mass analysis on quadrupole ion trap systems.

    PubMed

    Chen, Evan Xuguang; Gehm, Michael; Danell, Ryan; Wells, Mitch; Glass, Jeffrey T; Brady, David

    2014-07-01

    Conventionally, quadrupole ion trap mass spectrometers eject ions of different mass-to-charge ratio (m/z) in a sequential fashion by performing a scan of the rf trapping voltage amplitude. Due to the inherent sparsity of most mass spectra, the detector measures no signal for much of the scan time. By exploiting this sparsity property, we propose a new compressive and multiplexed mass analysis approach--multi Resonant Frequency Excitation (mRFE) ejection. This new approach divides the mass spectrum into several mass subranges and detects all the subrange spectra in parallel for increased mass analysis speed. Mathematical estimation of standard mass spectrum is demonstrated while statistical classification on the parallel measurements remains viable because of the sparse nature of the mass spectra. This method can reduce mass analysis time by a factor of 3-6 and increase system duty cycle by 2×. The combination of reduced analysis time and accurate compound classification is demonstrated in a commercial quadrupole ion trap (QIT) system. PMID:24806048

  15. The Coordinated Control of a Central Air Conditioning System Based on Variable Chilled Water Temperature and Variable Chilled Water Flow

    E-print Network

    Liu, J.; Mai, Y.; Liu, X.

    2006-01-01

    ICEBO2006, Shenzhen, China Control Systems for Energy Efficiency and Comfort, Vol. V-4-1 The Coordinated Control of a Central Air Conditioning System Based on Variable Chilled Water Temperature and Variable Chilled Water Flow Jinping LIU... Yuebang MAI Xuefeng LIU Associate professor Graduate student Instructor College of Electric Power, South China University of Technology Guangzhou. China Email: mpjpliu@scut.edu.cn Abstract: At present, regulation of water flow by means of pump...

  16. A New Source Model of Non-Tidal Mass Variability in Atmosphere, Oceans, Terrestrial Hydrosphere, and the Solid Earth for Simulation Studies of Future Satellite Gravity Missions

    NASA Astrophysics Data System (ADS)

    Dobslaw, Henryk; Bergmann-Wolf, Inga; Dill, Robert; Klemann, Volker; Kusche, Jürgen; Sasgen, Ingo; Thomas, Maik

    2014-05-01

    The ability of any satellite gravity mission concept to monitor mass transport processes in the Earth system is typically tested well ahead of its implementation by means of various simulation studies. Those studies often extend from the simulation of realistic orbits and instrumental data all the way down to the retrieval of global gravity field solution time-series. Basic requirement for all these simulations are realistic representations of the spatio-temporal mass variability in the different sub-systems of the Earth, as a source model for the orbit computations and assess the performance of the gravity field retrieval. For such simulations, a suitable source model is required to represent (i) high-frequency (~ daily) redistribution, for example, in the atmosphere and oceans, in order to realistically include the effects of temporal aliasing due to non-tidal high-frequency mass variability into the retrieved gravity fields. In parallel, (ii) low-frequency (weekly to monthly) variability needs to be modelled with realistic amplitudes, particularly at small spatial scales, in order to assess to what extent a new mission concept might provide further insight into physical processes currently not observable. The new source model presented in this study attempts to fulfil both requirements: Based on ECMWF's recent atmospheric reanalysis ERA Interim and corresponding simulations from numerical models of the other Earth system components, it offers spherical harmonic (SH) coefficients of the mass variability in atmosphere, oceans, the terrestrial hydrosphere including the ice-sheets and glaciers,as well as the solid Earth. Simulated features range from high temporal (6 hours) to long-term (inter-annual) with a spatial resolution of SH degree and order 180, encompassing a a period of 12 years. Associated with the source model, a de-aliasing model for atmospheric and oceanic high-frequency variability is available with augmented errors for a more realistic description of the process of the gravity field retrieval. Several features of this new dataset will be highlighted in this presentation in order to provide guidance for its application in upcoming future mission simulation studies.

  17. Key Metrics System for Variety Steering in Mass Customization

    Microsoft Academic Search

    Thorsten Blecker; Nizar Abdelkafi; Bernd Kaluza; Gerhard Friedrich

    2003-01-01

    The main goal of this paper is to provide a key metrics system for variety steering in mass customization. We distinguish between objective and subjective customer needs. The subjective needs are the individually realized and articulated requirements, whereas the objective needs are the real ones perceived by a fictive neutral perspective. We show that variety in mass customization has to

  18. GROUNDWATER MASS TRANSPORT AND EQUILIBRIUM CHEMISTRY MODEL FOR MULTICOMPONENT SYSTEMS

    EPA Science Inventory

    A mass transport model, TRANQL, for a multicomponent solution system has been developed. The equilibrium interaction chemistry is posed independently of the mass transport equations which leads to a set of algebraic equations for the chemistry coupled to a set of differential equ...

  19. Balloon borne optical disk mass storage system

    NASA Technical Reports Server (NTRS)

    Vanek, M. D.; Jennings, D. A.

    1991-01-01

    An on-board data recording system for balloon-borne interferometer using a vacuum operable, ruggedized WORM optical drive is presented. This system, as presently under development, provides 320 Mbytes of data storage (or approximately 11 hrs at the 64 kbits/sec telemetry rate of the experiment). It has the capability of recording the unmodified telemetry bit system as transmitted or doing some preprocessing of the data onboard. The system is compact and requires less than 28 watts of battery power to operate.

  20. Comparison of energy efficiency between variable refrigerant flow systems and ground source heat pump systems

    Microsoft Academic Search

    Tainzhen Hong; Xaiobing Liu

    2009-01-01

    With the current movement toward net zero energy buildings, many technologies are promoted with emphasis on their superior energy efficiency. The variable refrigerant flow (VRF) and ground source heat pump (GSHP) systems are probably the most competitive technologies among these. However, there are few studies reporting the energy efficiency of VRF systems compared with GSHP systems. In this article, a

  1. Comparison of energy efficiency between variable refrigerant flow systems and ground source heat pump systems

    Microsoft Academic Search

    Xiaobing Liu; Tianzhen Hong

    2010-01-01

    With the current movement towards net zero energy buildings, many technologies are promoted with emphasis on their superior energy efficiency. The variable refrigerant flow (VRF) and ground source heat pump (GSHP) systems are probably the most competitive technologies among these. However, there are few studies reporting the energy efficiency of VRF systems compared with GSHP systems. In this article, a

  2. NASA Langley Research Center's distributed mass storage system

    NASA Technical Reports Server (NTRS)

    Pao, Juliet Z.; Humes, D. Creig

    1993-01-01

    There is a trend in institutions with high performance computing and data management requirements to explore mass storage systems with peripherals directly attached to a high speed network. The Distributed Mass Storage System (DMSS) Project at NASA LaRC is building such a system and expects to put it into production use by the end of 1993. This paper presents the design of the DMSS, some experiences in its development and use, and a performance analysis of its capabilities. The special features of this system are: (1) workstation class file servers running UniTree software; (2) third party I/O; (3) HIPPI network; (4) HIPPI/IPI3 disk array systems; (5) Storage Technology Corporation (STK) ACS 4400 automatic cartridge system; (6) CRAY Research Incorporated (CRI) CRAY Y-MP and CRAY-2 clients; (7) file server redundancy provision; and (8) a transition mechanism from the existent mass storage system to the DMSS.

  3. First Order Chemical Reaction Effects on Exponentially Accelerated Vertical Plate with Variable Mass Diffusion in the Presence of Thermal Radiation

    NASA Astrophysics Data System (ADS)

    Muthucumaraswamy, R.; Lakshmi, C. S.

    2015-05-01

    Effects of transfer of mass and free convection on the flow field of an incompressible viscous fluid past an exponentially accelerated vertical plate with variable surface temperature and mass diffusion are studied. Results for velocity, concentration, temperature are obtained by solving governing equations using the Laplace transform technique. It is observed that the velocity increases with decreasing values of the chemical reaction parameter or radiation parameter. But the trend is just reversed with respect to the time parameter. The skin friction is also studied.

  4. Optimization of Bell's Inequality Violation For Continuous Variable Systems

    E-print Network

    G. Gour; F. C. Khanna; A. Mann; M. Revzen

    2003-10-21

    Two mode squeezed vacuum states allow Bell's inequality violation (BIQV) for all non-vanishing squeezing parameter $(\\zeta)$. Maximal violation occurs at $\\zeta \\to \\infty$ when the parity of either component averages to zero. For a given entangled {\\it two spin} system BIQV is optimized via orientations of the operators entering the Bell operator (cf. S. L. Braunstein, A. Mann and M. Revzen: Phys. Rev. Lett. {\\bf68}, 3259 (1992)). We show that for finite $\\zeta$ in continuous variable systems (and in general whenever the dimensionality of the subsystems is greater than 2) additional parameters are present for optimizing BIQV. Thus the expectation value of the Bell operator depends, in addition to the orientation parameters, on configuration parameters. Optimization of these configurational parameters leads to a unique maximal BIQV that depends only on $\\zeta.$ The configurational parameter variation is used to show that BIQV relation to entanglement is, even for pure state, not monotonic.

  5. Variable Structure Control of Decoupleable Systems and Attitude Control of Spacecraft in Prescence of Uncertainty

    Microsoft Academic Search

    Ashok Iyer; Sahjendra N. Singh

    1988-01-01

    This paper considers control of a class of uncertain nonlinear systems which can be decoupled by state variable feedback. A variable structure control (VSC) law is derived such that in the closed-loop system the output variable asymptotically tracks a given output trajectory in spite of the uncertainty in the system. Based on this result, a control law is derived for

  6. The influence of sea ice extent variability on the Greenland surface mass and energy balance

    NASA Astrophysics Data System (ADS)

    Tedesco, M.; Quillet, A.; Alexander, P. M.; Rennermalm, A. K.; Stroeve, J. C.; Fettweis, X.; Orantes, E. J.; Tuia, D.; Parkan, M.

    2012-12-01

    Sea ice variations are known to affect local surface air temperature regimes, but other influences, in particular atmospheric circulation, are important. Several recent studies have found that, via atmospheric transport, atmospheric warming driven by sea ice loss affects surrounding areas. Indeed, while observed amplified autumn warming is focused over the areas where the sea ice has disappeared in summers (e.g. Beaufort, Chukchi and E. Siberian seas), wind patterns spread the anomalous warmth over open water areas to adjacent land areas and may extend up to 1500 km inland during periods of rapid ice loss through the 21st century. It is plausible that changes in the sea-ice/open- water regime surrounding the ice sheet are capable of modulating Greenland surface melt and precipitation. Diminished sea ice around Greenland may lead to large fluxes of heat into the atmosphere that could lead to enhanced ice-sheet surface-melt, increased coastal water temperatures, alter the vertical stability of the atmosphere, moisture availability and regional baroclinicity. Here we report results concerning the combined analysis of sea ice extent estimated from spaceborne microwave observations, the outputs of a regional climate model (Modèle Atmosphérique Régional, MAR) and in-situ measured quantities. In particular, we study the impact of the open water along the coasts of Greenland (divided into 16 longitudinal zones and two latitudinal ones) on surface mass balance (e.g., meltwater production, runoff, precipitation) and surface energy quantities (e.g., albedo, sensible heat flux, etc.) simulated over the Greenland ice sheet for the period 1979 - 2011. Among other things, our results indicate a statistically significant correlation between open water spatio-temporal variability and integrated liquid water content, with correlation values being highest for the month of August along the Southwest region of Greenland (e.g., Kangerlussuaq). Such dependency persists even after the removal of the dependency of or results from near-surface temperature trends. We describe the results of our analysis concerning not only the southwest region but we also focus on the northeast area, where we find also statistically significant correlation between ILWC and open water fraction but later in the summer (e.g. September). We lastly discuss the potential sources of the differences between the results over the west and east regions and suggest a plan for future studies. To our knowledge, this is the first study aiming at combining observations and surface energy balance quantities to improve our understanding of the impact of sea ice loss on surface processes over the Greenland ice sheet.

  7. Mass spectrometer beam system for applications in the stratosphere

    NASA Technical Reports Server (NTRS)

    Mauersberger, K.

    1977-01-01

    A special gas inlet system is required for reduction of high ambient pressures to ion source operating pressures for mass spectrometer investigations in the stratosphere for the determination of the abundance of minor constituents. A system has been designed which combines a mass spectrometer and a gas inlet system reducing pressure by differential pumping using high-speed liquid helium pumps and small orifices. The gas particles are formed into a neutral beam with a flag mechanism proceeding into the mass spectrometer ion source where they are ionized for subsequent mass separation. A laboratory model has been tested under conditions simulating stratospheric pressures. It was shown that the process is able to identify gases with abundances below 10 to the -8th. Some of the problems associated with gas analysis of trace constituents have been alleviated, and other applications of the system have been identified, such as pollution control and medicine.

  8. Model-Based Systems Engineering Approach to Managing Mass Margin

    NASA Technical Reports Server (NTRS)

    Chung, Seung H.; Bayer, Todd J.; Cole, Bjorn; Cooke, Brian; Dekens, Frank; Delp, Christopher; Lam, Doris

    2012-01-01

    When designing a flight system from concept through implementation, one of the fundamental systems engineering tasks ismanaging the mass margin and a mass equipment list (MEL) of the flight system. While generating a MEL and computing a mass margin is conceptually a trivial task, maintaining consistent and correct MELs and mass margins can be challenging due to the current practices of maintaining duplicate information in various forms, such as diagrams and tables, and in various media, such as files and emails. We have overcome this challenge through a model-based systems engineering (MBSE) approach within which we allow only a single-source-of-truth. In this paper we describe the modeling patternsused to capture the single-source-of-truth and the views that have been developed for the Europa Habitability Mission (EHM) project, a mission concept study, at the Jet Propulsion Laboratory (JPL).

  9. Inclusive B-meson production at small p_T in the general-mass variable-flavor-number scheme

    E-print Network

    B. A. Kniehl; G. Kramer; I. Schienbein; H. Spiesberger

    2015-02-03

    We calculate the cross section for the inclusive production of B mesons in pp and ppbar collisions at next-to-leading order in the general-mass variable-flavor-number scheme and show that a suitable choice of factorization scales leads to a smooth transition to the fixed-flavor-number scheme. Our numerical results are in good agreement with data from the Tevatron and LHC experiments at small and at large transverse momenta.

  10. Dynamics of Line-driven Winds from Disks in Cataclysmic Variables. II. Mass-Loss Rates and Velocity Laws

    Microsoft Academic Search

    Achim Feldmeier; Isaac Shlosman; Peter Vitello

    1999-01-01

    We analyze the dynamics of two-dimensional stationary, line-driven winds from accretion disks in cataclysmic variable (CV) stars by generalizing the formalism of Castor, Abbott, and Klein (CAK) for O stars. In Paper I, we solved the wind Euler equation, derived its two eigenvalues, and addressed the solution topology and wind geometry. Here, we focus on mass-loss rates and velocity laws

  11. Regulator valve for hydraulic control system including variable displacement pump

    SciTech Connect

    Shibayama, T.; Sugano, K.

    1986-12-30

    A hydraulic control system is described for an automotive automatic transmission comprising: an automatic transmission actuated by hydraulic fluid; a variable capacity pump for supplying hydraulic fluid under pressure for actuating the automatic transmission. The pump has a control arrangement including a control chamber which varies the capacity of the pump in response to the pressure prevailing therein. A pressure regulator valve is described for regulating the output of the pump by draining off some of the fluid discharged by the pump and developing a control pressure, the regulator valve including a bore formed with: a first port which receives the output of the pump, a second port which fluidly communicates with the control chamber, and a drain port, the regulator valve further including a spool which is reciprocatively disposed in the bore and which is formed with first and second lands. The first land defines a first variable orifice between the first and second ports and the second land defining a second variable orifice between the second and drain ports; and a fixed flow restriction within the bore, for restricting fluid communication between the first and second ports and the second and drain ports. The fixed flow restriction is defined between the wall of the bore and a first portion of the spool which extends between the first and second lands. The portion has a diameter which is selected with respect to the diameter of that portion of the bore in which it is disposed so as to define a gap having a maximum width of 1.5 mm.

  12. Associations between circulating components of the renin-angiotensin-aldosterone system and left ventricular mass.

    PubMed Central

    Schunkert, H.; Hense, H. W.; Muscholl, M.; Luchner, A.; Kürzinger, S.; Danser, A. H.; Riegger, G. A.

    1997-01-01

    OBJECTIVE: Cardiac growth may be modulated in part by the trophic effects of neurohormones. The aim of the present study was to investigate the relation between the basal activity of the renin-angiotensin-aldosterone system and left ventricular mass. DESIGN: A population based sample of 615 middle-age subjects was studied by standardised echocardiography; anthropometric measurements; and biochemical quantification of renin, pro-renin, angiotensinogen, angiotensin converting enzyme (ACE), and aldosterone. RESULTS: Echocardiographic left ventricular mass index correlated significantly with arterial blood pressure, age, and body mass index. In addition, in men ACE activity was significantly related to left ventricular mass index in univariate (P = 0.0007) and multivariate analyses (P = 0.008). Men with left ventricular hypertrophy presented with significantly higher serum ACE concentrations than those with normal left ventricular mass index (P = 0.002). In both men and women serum aldosterone was strongly related to septal and posterior wall thickness. Furthermore, in women serum aldosterone was positively and independently associated with left ventricular mass index (P = 0.0001). This effect was most prominent in hypertensive women. Finally, women with left ventricular hypertrophy presented with significantly higher serum aldosterone (P = 0.01). No significant associations with left ventricular mass index were observed for angiotensinogen, renin, or pro-renin. CONCLUSIONS: The data suggest that the variability of serum ACE or aldosterone, as occurred in this large population based sample, may contribute to the modulation of left ventricular mass. Images PMID:9038690

  13. Optical mass memory investigations. Volume 3: Considerations for the development of a DIGIMEM archival optical mass storage system

    NASA Technical Reports Server (NTRS)

    Zech, R. G. (editor)

    1977-01-01

    Basic considerations relevant to the implementation of an archival mass storage system based on DIGIMEM technology are discussed in terms of evolving a new generation of mass storage systems which are archival, and cost effective.

  14. Small system for tritium accelerator mass spectrometry

    DOEpatents

    Roberts, M.L.; Davis, J.C.

    1993-02-23

    Apparatus for ionizing and accelerating a sample containing isotopes of hydrogen and detecting the ratios of hydrogen isotopes contained in the sample is disclosed. An ion source generates a substantially linear ion beam including ions of tritium from the sample. A radio-frequency quadrupole accelerator is directly coupled to and axially aligned with the source at an angle of substantially zero degrees. The accelerator accelerates species of the sample having different mass to different energy levels along the same axis as the ion beam. A spectrometer is used to detect the concentration of tritium ions in the sample. In one form of the invention, an energy loss spectrometer is used which includes a foil to block the passage of hydrogen, deuterium and [sup 3]He ions, and a surface barrier or scintillation detector to detect the concentration of tritium ions. In another form of the invention, a combined momentum/energy loss spectrometer is used which includes a magnet to separate the ion beams, with Faraday cups to measure the hydrogen and deuterium and a surface barrier or scintillation detector for the tritium ions.

  15. Small system for tritium accelerator mass spectrometry

    DOEpatents

    Roberts, Mark L. (Livermore, CA); Davis, Jay C. (Livermore, CA)

    1993-01-01

    Apparatus for ionizing and accelerating a sample containing isotopes of hydrogen and detecting the ratios of hydrogen isotopes contained in the sample is disclosed. An ion source generates a substantially linear ion beam including ions of tritium from the sample. A radio-frequency quadrupole accelerator is directly coupled to and axially aligned with the source at an angle of substantially zero degrees. The accelerator accelerates species of the sample having different mass to different energy levels along the same axis as the ion beam. A spectrometer is used to detect the concentration of tritium ions in the sample. In one form of the invention, an energy loss spectrometer is used which includes a foil to block the passage of hydrogen, deuterium and .sup.3 He ions, and a surface barrier or scintillation detector to detect the concentration of tritium ions. In another form of the invention, a combined momentum/energy loss spectrometer is used which includes a magnet to separate the ion beams, with Faraday cups to measure the hydrogen and deuterium and a surface barrier or scintillation detector for the tritium ions.

  16. Self-learning fuzzy logic system for in situ, in-process diagnostics of mass flow controller (MFC)

    Microsoft Academic Search

    Ram K. Ramamurthi

    1994-01-01

    An improvement in the yield of better quality wafers requires an accurate control of various process variables. The control should include timely diagnosis and appropriate in-situ, in-process adjustments for drifts in these variables. One such scheme, a self-learning fuzzy logic system, is developed in this study for correcting drifts in the calibration of mass flow controllers (MFC's) that control the

  17. On the capability of SWARM for estimating time-variable gravity fields and mass variations

    E-print Network

    Stuttgart, Universität

    estimation. Tailored processing strategies such as Gaussian and Kalman filtering and leakage reduction tools of the most important scientific results of GRACE is the estimation of mass trends such as the ice mass loss on Greenland or water accumulation in the Amazon Basin. The potential of SWARM for the continuation

  18. On the relationship between climatic variables and pressure systems over Saudi Arabia in the winter season

    NASA Astrophysics Data System (ADS)

    Hasanean, H. M.; Basset, H. Abdel; Hussein, M. A. A.

    2015-05-01

    The synoptic circulation over Saudi Arabia is complicated and frequently governed by the effect of large-scale pressure systems. In this work, we used NCEP-NCAR global data to illustrate the relationship between climatic variables and the main pressure systems that affect the weather and climate of Saudi Arabia, and also to investigate the influence of these pressure systems on surface air temperature (SAT) and rainfall over the region in the winter season. It was found that there are two primary patterns of pressure that influence the weather and climate of Saudi Arabia. The first occurs in cases of a strengthening Subtropical High (SubH), a weakening Siberian High (SibH), a deepening of the Icelandic Low (IceL), or a weakening of the Sudanese Low (SudL). During this pattern, the SubH combines with the SibH and an obvious increase of sea level pressure (SLP) occurs over southern European, the Mediterranean, North Africa, and the Middle East. This belt of high pressure prevents interaction between midlatitude and extratropical systems, which leads to a decrease in the SAT, relative humidity (RH) and rainfall over Saudi Arabia. The second pattern occurs in association with a weakening of the SubH, a strengthening of the SibH, a weakening of the IceL, or a deepening of the SudL. The pattern arising in this case leads to an interaction between two different air masses: the first (cold moist) air mass is associated with the Mediterranean depression travelling from west to east, while the second (warm moist) air mass is associated with the northward oscillation of the SudL and its inverted V-shape trough. The interaction between these two air masses increases the SAT, RH and the probability of rainfall over Saudi Arabia, especially over the northwest and northeast regions.

  19. Continuously proportional variable geometry turbocharger system and method of control

    SciTech Connect

    Younessi, R.; Rini, G.T.

    1992-06-23

    This patent describes a system for performing closed loop control of a variable geometry turbocharger (VGT) utilized in an internal combustion engine. It comprises VGT actuator means for changing the geometric configuration of the VGT in response to an actuator control signal; sensor means for detecting selected engine operating parameters including a VGT actuator parameter and an engine intake manifold parameter, and generating output signals representative thereof; means for outputting a target VGT actuator parameter value and a target intake manifold parameter valve based on the values of selected sensor means output signals; means for determining whether the engine is in a steady state or a transient state of operation based on the values of selected sensor means output signals; and means for developing an actuator control signal based on one of the target parameter values as a function of the determined engine operating state.

  20. Entanglement in continuous variable systems: Recent advances and current perspectives

    E-print Network

    Adesso, G; Adesso, Gerardo; Illuminati, Fabrizio

    2007-01-01

    We review the theory of continuous-variable entanglement with special emphasis on foundational aspects, conceptual structures, and mathematical methods. Much attention is devoted to the discussion of separability criteria and entanglement properties of Gaussian states, for their great practical relevance in applications to quantum optics and quantum information, as well as for the very clean framework that they allow for the study of the structure of nonlocal correlations. We give a self-contained introduction to phase-space and symplectic methods in the study of Gaussian states of infinite-dimensional bosonic systems. We review the most important results on the separability and distillability of Gaussian states and discuss the main properties of bipartite entanglement. These include the extremal entanglement, minimal and maximal, of two-mode mixed Gaussian states, the ordering of two-mode Gaussian states according to different measures of entanglement, the unitary (reversible) localization, and the scaling o...

  1. Antarctic Circumpolar Current System and its Response to Atmospheric Variability 

    E-print Network

    Kim, Yong Sun 1976-

    2012-08-16

    forcing variability in the Southern Ocean. All three ACC fronts have experienced large seasonal to decadal variability throughout the satellite altimetry era. The general seasonal tendency for each of these jets, with respect to long-term mean positions...

  2. Variability of air mass occurrence in southern Poland (1951-2010)

    NASA Astrophysics Data System (ADS)

    Kotas, Pawe?; Twardosz, Robert; Nieckarz, Zenon

    2013-11-01

    The paper discusses the frequency, persistence and succession sequence of six types of air mass during the period 1951-2010. The study, which relied on a calendar of air masses in southern Poland published by T. Nied?wied?, concludes that there is no simple relationship between the persistence and the frequency of specific air masses in the region. The study found that there was a great variety in the persistence of specific types of air mass and that persistence depended more on the direction of air mass advection than on their frequency of occurrence. The study also failed to identify any strict overall rule of succession, as any air mass could follow after any other, but certain finer-grained patterns emerged. In winter and summer, arctic air (A) never followed directly after tropical air (T) or vice versa. Also, the most frequent succession sequence identified was from Polar maritime fresh air (mPf) to Polar maritime old and it accounted for the vast majority of successions from mPf into any other air mass (63 % annually and 76 % in summer).

  3. Orbits and masses in the young triple system TWA 5

    E-print Network

    Köhler, R; Petr-Gotzens, M G; Correia, S

    2013-01-01

    We aim to improve the orbital elements and determine the individual masses of the components in the triple system TWA 5. Five new relative astrometric positions in the H band were recorded with the adaptive optics system at the Very Large Telescope (VLT). We combine them with data from the literature and a measurement in the Ks band. We derive an improved fit for the orbit of TWA 5Aa-b around each other. Furthermore, we use the third component, TWA 5B, as an astrometric reference to determine the motion of Aa and Ab around their center of mass and compute their mass ratio. We find an orbital period of 6.03+/-0.01 years and a semi-major axis of 63.7+/-0.2 mas (3.2+/-0.1 AU). With the trigonometric distance of 50.1+/-1.8 pc, this yields a system mass of 0.9+/-0.1 Msun, where the error is dominated by the error of the distance. The dynamical mass agrees with the system mass predicted by a number of theoretical models if we assume that TWA5 is at the young end of the age range of the TW Hydrae association. We fin...

  4. Building and managing high performance, scalable, commodity mass storage systems

    NASA Technical Reports Server (NTRS)

    Lekashman, John

    1998-01-01

    The NAS Systems Division has recently embarked on a significant new way of handling the mass storage problem. One of the basic goals of this new development are to build systems at very large capacity and high performance, yet have the advantages of commodity products. The central design philosophy is to build storage systems the way the Internet was built. Competitive, survivable, expandable, and wide open. The thrust of this paper is to describe the motivation for this effort, what we mean by commodity mass storage, what the implications are for a facility that performs such an action, and where we think it will lead.

  5. Goddard Conference on Mass Storage Systems and Technologies, Volume 1

    NASA Technical Reports Server (NTRS)

    Kobler, Ben (editor); Hariharan, P. C. (editor)

    1993-01-01

    Copies of nearly all of the technical papers and viewgraphs presented at the Goddard Conference on Mass Storage Systems and Technologies held in Sep. 1992 are included. The conference served as an informational exchange forum for topics primarily relating to the ingestion and management of massive amounts of data and the attendant problems (data ingestion rates now approach the order of terabytes per day). Discussion topics include the IEEE Mass Storage System Reference Model, data archiving standards, high-performance storage devices, magnetic and magneto-optic storage systems, magnetic and optical recording technologies, high-performance helical scan recording systems, and low end helical scan tape drives. Additional topics addressed the evolution of the identifiable unit for processing purposes as data ingestion rates increase dramatically, and the present state of the art in mass storage technology.

  6. Semiautomatic Data-Collection Systems for Mass Spectrometers

    Microsoft Academic Search

    P. E. Moreland; C. M. Stevens; D. B. Walling

    1967-01-01

    Two programmed digital data-collection systems have been developed and used with static-field mass spectrometers to improve the precision of isotopic analyses of solid samples and to reduce the time required for collection and reduction of data. A large high-sensitivity spectrometer using ion pulse counting detection has been equipped with a programmer and multiscaler so that up to four masses can

  7. Solitary choroidal mass as the presenting sign in systemic sarcoidosis.

    PubMed Central

    Olk, R. J.; Lipmann, M. J.; Cundiff, H. C.; Daniels, J.

    1983-01-01

    A solitary choroidal mass with an overlying neurosensory retinal detachment was seen in an otherwise healthy 25-year-old Caucasian female. Ocular and general physical examinations, serum chemistry, and pathological examination of a lymph node biopsy confirmed sarcoidosis as the cause for the choroidal mass. Treatment with systemic steroids resulted in resolution of the lesion and return of normal visual acuity. Images PMID:6671099

  8. Sodium Variable Conductance Heat Pipe for Radioisotope Stirling Systems

    NASA Technical Reports Server (NTRS)

    Tarau, Calin; Anderson, William G.; Walker, Kara

    2009-01-01

    In a Stirling radioisotope system, heat must continually be removed from the General Purpose Heat Source (GPHS) modules to maintain the modules and surrounding insulation at acceptable temperatures. Normally, the Stirling convertor provides this cooling. If the converter stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS, and also ending the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) has been designed to allow multiple stops and restarts of the Stirling convertor in an Advanced Stirling Radioisotope Generator (ASRG). When the Stirling convertor is turned off, the VCHP will activate when the temperatures rises 30 C above the setpoint temperature. A prototype VCHP with sodium as the working fluid was fabricated and tested in both gravity aided and against gravity conditions for a nominal heater head temperature of 790 C. The results show very good agreement with the predictions and validate the model. The gas front was located at the exit of the reservoir when heater head temperature was 790 C while cooling was ON, simulating an operating Advanced Stirling Converter (ASC). When cooling stopped, the temperature increased by 30 C, allowing the gas front to move past the radiator, which transferred the heat to the case. After resuming the cooling flow, the front returned at the initial location turning OFF the VCHP. The against gravity working conditions showed a colder reservoir and faster transients.

  9. How does variability of immune system genes affect placentation?

    PubMed

    Colucci, F; Boulenouar, S; Kieckbusch, J; Moffett, A

    2011-08-01

    Formation of the placenta is a crucial step in mammalian pregnancy. Apart from its function in ensuring an optimal supply of nutrients and oxygen to the fetus, the placenta is also the interface at which allo-recognition of invading trophoblast cells by the maternal immune system can potentially occur. We summarise here the "state of the art" on how variability of immune system genes that code for major histocompatibility complex (MHC) molecules and natural killer receptors (NKR) may impact on human placentation. MHC and NKR are the most polymorphic human genes. Our recent reports point out that specific combinations of fetal MHC and maternal NKR genes in humans correlate with the risk of pre-eclampsia, recurrent miscarriage (RM) and fetal growth restriction (FGR). Research in this field is still at an early stage and future studies in mouse and humans will be needed before the results can be translated to clinical applications. We discuss our recent work, as well as the opportunities offered by mouse genetics, to understand the cellular and molecular mechanisms underlying immune interactions at the maternal-fetal interface. PMID:21665273

  10. How does variability of immune system genes affect placentation?

    PubMed Central

    Colucci, F.; Boulenouar, S.; Kieckbusch, J.; Moffett, A.

    2011-01-01

    Formation of the placenta is a crucial step in mammalian pregnancy. Apart from its function in ensuring an optimal supply of nutrients and oxygen to the fetus, the placenta is also the interface at which allo-recognition of invading trophoblast cells by the maternal immune system can potentially occur. We summarise here the “state of the art” on how variability of immune system genes that code for major histocompatibility complex (MHC) molecules and natural killer receptors (NKR) may impact on human placentation. MHC and NKR are the most polymorphic human genes. Our recent reports point out that specific combinations of fetal MHC and maternal NKR genes in humans correlate with the risk of pre-eclampsia, recurrent miscarriage (RM) and fetal growth restriction (FGR). Research in this field is still at an early stage and future studies in mouse and humans will be needed before the results can be translated to clinical applications. We discuss our recent work, as well as the opportunities offered by mouse genetics, to understand the cellular and molecular mechanisms underlying immune interactions at the maternal-fetal interface. PMID:21665273

  11. THE HD 192263 SYSTEM: PLANETARY ORBITAL PERIOD AND STELLAR VARIABILITY DISENTANGLED

    SciTech Connect

    Dragomir, Diana; Matthews, Jaymie M. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T1Z1 (Canada); Kane, Stephen R.; Ciardi, David R.; Von Braun, Kaspar [NASA Exoplanet Science Institute, Caltech, MS 100-22, 770 South Wilson Avenue, Pasadena, CA 91125 (United States); Henry, Gregory W. [Center of Excellence in Information Systems, Tennessee State University, 3500 John A. Merritt Blvd., Box 9501, Nashville, TN 37209 (United States); Fischer, Debra A. [Department of Astronomy, Yale University, New Haven, CT 06511 (United States); Howard, Andrew W. [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); Jensen, Eric L. N. [Department of Physics and Astronomy, Swarthmore College, Swarthmore, PA 19081 (United States); Laughlin, Gregory [UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States); Mahadevan, Suvrath; Pilyavsky, Genady; Wang, Sharon X.; Wright, Jason T., E-mail: diana@phas.ubc.ca [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States)

    2012-07-20

    As part of the Transit Ephemeris Refinement and Monitoring Survey, we present new radial velocities and photometry of the HD 192263 system. Our analysis of the already available Keck-HIRES and CORALIE radial velocity measurements together with the five new Keck measurements we report in this paper results in improved orbital parameters for the system. We derive constraints on the size and phase location of the transit window for HD 192263b, a Jupiter-mass planet with a period of 24.3587 {+-} 0.0022 days. We use 10 years of Automated Photoelectric Telescope photometry to analyze the stellar variability and search for planetary transits. We find continuing evidence of spot activity with periods near 23.4 days. The shape of the corresponding photometric variations changes over time, giving rise to not one but several Fourier peaks near this value. However, none of these frequencies coincides with the planet's orbital period and thus we find no evidence of star-planet interactions in the system. We attribute the {approx}23 day variability to stellar rotation. There are also indications of spot variations on longer (8 years) timescales. Finally, we use the photometric data to exclude transits for a planet with the predicted radius of 1.09 R{sub J} , and as small as 0.79 R{sub J} .

  12. Performance evaluation of mass storage systems for scientific databases

    SciTech Connect

    Segev, A. [Univ. of California, Berkeley, CA (United States). Haas School of Business]|[Lawrence Berkeley Lab., CA (United States). Information and Computing Sciences Div.; Seshadri, S. [Univ. of California, Berkeley, CA (United States). Haas School of Business; Rotem, D. [Lawrence Berkeley Lab., CA (United States). Information and Computing Sciences Div.

    1994-09-01

    Mass storage systems for computers are the solution to economic storage of vast volumes of data. These systems evolved from the traditional tape libraries manned by operating personnel and the automation of the storage and retrieval function has led to significant improvement in performance. But in contrast to traditional computer systems, little work has been done to characterize performance in terms of the design parameters. The design and performance analysis of mass storage systems is complicated due to several reasons. A major reason for the complexity is the time lags that may occur in retrieving parts of the information meant for the same query. The usual queuing models used for analyzing disk performance are not directly applicable, because there is greater scope for working in parallel in mass storage systems such as robotic libraries, which help mitigate these shortcomings. In this note, robotic libraries are modeled as queueing systems and explicit results related to performance are obtained. The physical model corresponds to a mass storage system, where the information is stored in cassettes, which are retrieved by robots to be read using one or two read heads. The results pertain to the effect of file splitting on cassettes, and optimal configuration and control of robots that perform the retrieval and storage functions.

  13. An assessment of the evidence from ATLAS3D for a variable initial mass function

    NASA Astrophysics Data System (ADS)

    Clauwens, Bart; Schaye, Joop; Franx, Marijn

    2015-06-01

    The ATLAS3D Survey has reported evidence for a non-universal stellar initial mass function (IMF) for early-type galaxies (ETGs). The IMF was constrained by comparing stellar mass measurements from kinematic data with those from spectral energy distribution (SED) fitting. Here, we investigate possible effects of scatter in the reported stellar mass measurements and their potential impact on the IMF determination. We find that a trend of the IMF mismatch parameter with the kinematic mass-to-light ratio, comparable to the trend observed by Cappellari et al., could arise if the Gaussian errors of the kinematic mass determination are typically 30 per cent. Without additional data, it is hard to separate between the option that the IMF has a true large intrinsic variation or the option that the errors in the determination are larger than anticipated. A correlation of the IMF with other properties would help to make this distinction, but no strong correlation has been found yet. The strongest correlation is with velocity dispersion. However, it has a large scatter and the correlation depends on sample selection and distance measurements. The correlation with velocity dispersion could be partly caused by the colour-dependent calibration of the surface brightness fluctuation distances of Tonry et al. We find that the K-band luminosity-limited ATLAS3D Survey is incomplete for the highest M/L galaxies below 1010.3 M?. There is a significant IMF-velocity dispersion trend for galaxies with SED masses above this limit, but no trend for galaxies with kinematic masses above this limit. We also find an IMF trend with distance, but no correlation between nearest neighbour ETGs, which excludes a large environmental dependence. Our findings do not rule out the reported IMF variations, but they suggest that further study is needed.

  14. Maternal provisioning, sibling rivalry and seed mass variability in the dioecious shrub Rhamnus alpinus

    Microsoft Academic Search

    M. J. Bañuelos; J. R. Obeso

    2003-01-01

    In this paper, we study the sources of variability in seed provisioning in Rhamnus alpinus, a dioecious shrub producing three-seeded fleshy fruits (range 1–4). Discarding position effects in access to resources as a source of variation, since pyrenes are radially oriented inside the fruit, we conducted a pollination experiment, in which different pollen donors were used to make single and

  15. Ionic Current Variability and Functional Stability in the Nervous System

    PubMed Central

    Golowasch, Jorge

    2015-01-01

    Identified neurons in different animals express ionic currents at highly variable levels (population variability). If neuronal identity is associated with stereotypical function, as is the case in genetically identical neurons or in unambiguously identified individual neurons, this variability poses a conundrum: How is activity the same if the components that generate it—ionic current levels—are different? In some cases, ionic current variability across similar neurons generates an output gradient. However, many neurons produce very similar output activity, despite substantial variability in ionic conductances. It appears that, in many such cells, conductance levels of one ionic current vary in proportion to the conductance levels of another current. As a result, in a population of neurons, these conductances appear to be correlated. Here, I review theoretical and experimental work that suggests that neuronal ionic current correlation can reduce the global ionic current variability and can contribute to functional stability.

  16. Heat and mass transfer considerations in advanced heat pump systems

    SciTech Connect

    Panchal, C.B.; Bell, K.J.

    1992-01-01

    Advanced heat-pump cycles are being investigated for various applications. However, the working media and associated thermal design aspects require new concepts for maintaining high thermal effectiveness and phase equilibrium for achieving maximum possible thermodynamic advantages. In the present study, the heat- and mass-transfer processes in two heat-pump systems -- those based on absorption processes, and those using refrigerant mixtures -- are analyzed. The major technical barriers for achieving the ideal performance predicted by thermodynamic analysis are identified. The analysis provides general guidelines for the development of heat- and mass-transfer equipment for advanced heat-pump systems.

  17. Heat and mass transfer considerations in advanced heat pump systems

    SciTech Connect

    Panchal, C.B.; Bell, K.J.

    1992-08-01

    Advanced heat-pump cycles are being investigated for various applications. However, the working media and associated thermal design aspects require new concepts for maintaining high thermal effectiveness and phase equilibrium for achieving maximum possible thermodynamic advantages. In the present study, the heat- and mass-transfer processes in two heat-pump systems -- those based on absorption processes, and those using refrigerant mixtures -- are analyzed. The major technical barriers for achieving the ideal performance predicted by thermodynamic analysis are identified. The analysis provides general guidelines for the development of heat- and mass-transfer equipment for advanced heat-pump systems.

  18. Spectral analysis for semi-infinite mass-spring systems

    E-print Network

    Rafael del Rio; Luis O. Silva

    2014-07-29

    We study how the spectrum of a Jacobi operator changes when this operator is modified by a certain finite rank perturbation. The operator corresponds to an infinite mass-spring system and the perturbation is obtained by modifying one interior mass and one spring of this system. In particular, there are detailed results of what happens in the spectral gaps and which eigenvalues do not move under the modifications considered. These results were obtained by a new tecnique of comparative spectral analysis and they generalize and include previous results for finite and infinite Jacobi matrices.

  19. Passive and Variable Active Switching Control by Mechanical Energy with Dual Structural Mass Damper

    NASA Astrophysics Data System (ADS)

    Abe, Naoto; Nishioka, Nobuhiro

    Switching vibration control between dynamic absorber and active control has been proposed for the dual structural vibration device on the basis of the kinetic energy as the threshold. For the active control with a fixed feedback gain, the threshold of switching should be set conservative and the effect of the active control was not enough. Therefore, a variable feedback gain control is introduced, which is assumed the mechanical energy as an indicator. It is expected that the actuator moves in a stroke range as possible and the performance will be better than the conventional switching control. In this paper, the effective variable feedback and switching control on the basis of mechanical energy as the two threshold are considered by experimental results.

  20. Submillimeter photometry and disk masses of T Tauri disk systems

    SciTech Connect

    Adams, F.C.; Emerson, J.P.; Fuller, G.A. (Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (USA) Queen Mary and Westfield College, London (England) California Univ., Berkeley (USA))

    1990-07-01

    Submillimeter photometric measurements of T Tauri stars, which are suspected of having circumstellar disks, are presented. The sources T Tau, HL Tau, DG Tau, HK Tau, DO Tau, GM Aur in Taurus-Auriga and VSSG 23 in Ophiuchus were detected. For the most luminous sources, detections were obtained at all of the observed wavelengths (1100, 800, 600, 450, and 350 microns); for the less luminous sources, detections were obtained only at the longer wavelengths (usually 800 and 1100 microns). The submillimeter emission is interpreted as arising from circumstellar disks and estimates are derived for the disk mass which are found to be in the range 0.05-1.0 solar mass. These disk masses are larger than the minimum-mass solar nebula and suggest that planets can form in these systems. 64 refs.

  1. Ultrasensitive nanomechanical mass sensor using hybrid opto-electromechanical systems.

    PubMed

    Jiang, Cheng; Cui, Yuanshun; Zhu, Ka-Di

    2014-06-01

    Nanomechanical resonators provide an unparalleled mass sensitivity sufficient to detect single biomolecules, viruses and nanoparticles. In this work we propose a scheme for mass sensing based on the hybrid opto-electromechanical system, where a mechanical resonator is coupled to an optical cavity and a microwave cavity simultaneously. When the two cavities are driven by two pump fields with proper frequencies and powers, a weak probe field is used to scan across the optical cavity resonance frequency. The mass of a single baculovirus landing onto the surface of the mechanical resonator can be measured by tracking the resonance frequency shift in the probe transmission spectrum before and after the deposition. We also propose a nonlinear mass sensor based on the measurement of the four-wave mixing (FWM) spectrum, which can be used to weigh a single 20-nm-diameter gold nanoparticle with sub-femtogram resolution. PMID:24921569

  2. Variable Speed Wind Turbines for Power System Stability Enhancement

    Microsoft Academic Search

    Nayeem Rahmat Ullah; Torbjrn Thiringer

    2007-01-01

    This paper investigates possible improvements in grid voltage stability and transient stability with wind energy converter units using modified P\\/Q control. The voltage source converter (VSC) in modern variable speed wind turbines is utilized to achieve this enhancement. The findings show that using only available hardware for variable-speed turbines improvements could be obtained in all cases. Moreover, it was found

  3. Time-variable gravity observations of ice sheet mass balance: Precision and limitations of the GRACE satellite data

    NASA Astrophysics Data System (ADS)

    Velicogna, I.; Wahr, J.

    2013-06-01

    Time-variable gravity data from the Gravity Recovery and Climate Experiment (GRACE) mission have been available since 2002 to estimate the mass balance of the Greenland and Antarctic Ice Sheets. We analyze current progress and uncertainties in GRACE estimates of ice sheet mass balance. We discuss the impacts of errors associated with spherical harmonic truncation, spatial averaging, temporal sampling, and leakage from other time-dependent signals (e.g., glacial isostatic adjustment (GIA)). The largest sources of error for Antarctica are the GIA correction, the omission of l=1 terms, nontidal changes in ocean mass, and measurement errors. For Greenland, the errors come mostly from the uncertainty in the scaling factor. Using Release 5.0 (RL05) GRACE fields for January 2003 through November 2012, we find a mass change of -258 ± 41 Gt/yr for Greenland, with an acceleration of -31 ± 6 Gt/yr2, and a loss that migrated clockwise around the ice sheet margin to progressively affect the entire periphery. For Antarctica, we report changes of -83 ± 49 and -147 ± 80 Gt/yr for two GIA models, with an acceleration of -12 ± 9 Gt/yr2 and a dominance from the southeast pacific sector of West Antarctica and the Antarctic Peninsula.

  4. System for controlling the pressure of oil in a system for a continuously variable transmission

    Microsoft Academic Search

    Satoh

    1989-01-01

    This patent describes a control system for a continuously variable transmission for transmitting the power of an internal combustion engine, the transmission comprising a drive pulley having a hydraulically shiftable first disc and a first hydraulic cylinder for shifting the disc, a driven pulley having a hydraulically shiftable second disc and a second hydraulic cylinder for operating the second disc,

  5. Energy efficient fuzzy based combined variable refrigerant volume and variable air volume air conditioning system for buildings

    Microsoft Academic Search

    R. Karunakaran; S. Iniyan; Ranko Goic

    2010-01-01

    Energy conservative building design has triggered greater interests in developing flexible and sophisticated air conditioning systems capable of achieving enhanced energy-savings potential without sacrificing the desired thermal comfort and indoor air quality (IAQ). This research work greatly aimed at achieving enhanced energy conservation, good thermal comfort and better IAQ for space conditioning with the application of combined variable refrigerant volume

  6. The Longterm Variability of 4u 1705-44---A Chaotic System?

    NASA Astrophysics Data System (ADS)

    Boyd, Patricia T.; Nichols, Rebecca; Smale, Alan

    2015-01-01

    The bright low-mass X-ray binary 4U 1705-44, a bursting Atoll source, exhibits longterm aperiodic variability with a timescale of several hundred days. The All-Sky Monitor (ASM) aboard the Rossi X-ray Timing Explorer (RXTE) observed 4U 1705-44 continuously from December 1995 through January 2012. MAXI, the Japanese X-ray All-Sky Monitor aboard the International Space Station observed the source from August 2009 through the present. Combining the ASM and MAXI data sets yeilds a continuous, uninterrupted, evenly spaced time series containing over fifty cycles at the timescale of interest. We use traditional and novel time series analysis techniques to analyze the longterm variability. A phase space embedding of the flux versus its first derivative shows a strong resemblence to the canonical double-welled nonlinear Duffing osciallator. We find a range of parameters and initial conditions for which the Duffing oscillator closely follows the time evolution of 4U 1705-44. We find evidence for unstable periodic orbits embedded in the aperiodc variabiity of 4U 1705-44, and argue that the period-1 orbit has a period of ~120 days. Clear signatures of period-1, period-2 and period-3 orbits are found in the light curve. We extract these orbits from both the 4U 1705-44 and Duffing oscillator time series and compare their topological information in phase space. It appears that the X-ray long term time variability of 4U 1705-44 can be described by a Duffing oscillator. We discuss the implications of this discovery on the allowable models to describe the longterm variability of 4U 1705-44 and, by extention, to the allowable models describing the class of X-ray binaries which show high amplitude, longterm variabilty at timescales many times the orbital periods of the systems.

  7. The Size And Shape Of The Mass Transfer Nozzle In Eccentric Interacting Binary Star Systems

    NASA Astrophysics Data System (ADS)

    Mancini, Alyssa; Haggerty, C.; Sepinsky, J.

    2012-01-01

    In order to determine the amount of mass lost from a star which just fills its Roche Lobe, it is imperative to accurately calculate the size of the nozzle -- the area through which the mass flows. This is normally bounded by the equipotential surface where the density of the exponential atmosphere drops by one scale height. When the stars are in an eccentric orbit, Sepinsky et al. (2007) found that the equipotential surfaces defining the peanut-shaped shell ordinarily enclosing the two stars can "open up", no longer enclosing both stars. Furthermore, when attempting to calculate the orbit-variable mass transfer rate for eccentric systems, Haggerty and Sepinsky (2011) discovered that the equipotential surface defining the outer edge of the nozzle may "open up” -- and that this can occur closer to the donor star than its inner Lagrangian point (L1). In such a case, the nozzle is undefined at L1. Here, we develop a method for calculating the effective area of mass transfer by finding the area of the rings bounded at small radii by the Roche Lobe of the donor and at large radii by the equipotential surface. We calculate the area of the ring and its proximity to the L1 point as a function of eccentricity and the binary parameters. We then compare the mass transfer rate calculated for this area to other recent calculations of the mass transfer rate in eccentric binaries.

  8. Distributions and variability of particulate organic matter in a coastal upwelling system

    E-print Network

    Pierce, Stephen

    Distributions and variability of particulate organic matter in a coastal upwelling system L. Karp (2004), Distributions and variability of particulate organic matter in a coastal upwelling system, J of information on POM in such systems. Basic questions such as, how is POM distributed across the shelf, what

  9. Development and animal experiment of variable focusing HIFU system for prostate cancer treatment

    Microsoft Academic Search

    Kazunari Ishida; Jun Kubota; Tsuyosi Mitake; Roy F. Carlson; Ralf Seip; Narendra T. Sanghvi; Takashi Azuma; Kazuaki Sasaki; Ken-ichi Kawabata; Shin-ichiro Umemura

    Objective: A prototype variable focal length array transducer system for a high-throughput HIFU (High Intensity Focused Ultrasound) has been developed and animal experiments have been carried out in order to demonstrate an ability to treat prostate through rectum. Methods: Multi-elements linear array transducers with cylindrical acoustic lens are used to make the variable focal length system. The system consists of

  10. Control of seismic-excited buildings using active variable stiffness systems

    Microsoft Academic Search

    J. N. Yang; Z. Li; J. C. Wu

    1994-01-01

    Active variable stiffness (AVS) systems have been demonstrated to be effective in response control of buildings subjected to earthquake excitations. Based on the theory of variable structure system (VSS) or sliding mode control (SMC), control methods for applications of AVS systems to seismic-excited buildings are presented. In addition to full-state feedback controllers, general static output feedback controllers as well as

  11. Characteristics, processes, and causes of the spatio-temporal variabilities of the East Asian monsoon system

    NASA Astrophysics Data System (ADS)

    Huang, Ronghui; Chen, Jilong; Wang, Lin; Lin, Zhongda

    2012-09-01

    Recent advances in the study of the characteristics, processes, and causes of spatio-temporal variabilities of the East Asian monsoon (EAM) system are reviewed in this paper. The understanding of the EAM system has improved in many aspects: the basic characteristics of horizontal and vertical structures, the annual cycle of the East Asian summer monsoon (EASM) system and the East Asian winter monsoon (EAWM) system, the characteristics of the spatio-temporal variabilities of the EASM system and the EAWM system, and especially the multiple modes of the EAM system and their spatio-temporal variabilities. Some new results have also been achieved in understanding the atmosphere-ocean interaction and atmosphere-land interaction processes that affect the variability of the EAM system. Based on recent studies, the EAM system can be seen as more than a circulation system, it can be viewed as an atmosphere-ocean-land coupled system, namely, the EAM climate system. In addition, further progress has been made in diagnosing the internal physical mechanisms of EAM climate system variability, especially regarding the characteristics and properties of the East Asia-Pacific (EAP) teleconnection over East Asia and the North Pacific, the "Silk Road" teleconnection along the westerly jet stream in the upper troposphere over the Asian continent, and the dynamical effects of quasi-stationary planetary wave activity on EAM system variability. At the end of the paper, some scientific problems regarding understanding the EAM system variability are proposed for further study.

  12. Accurate prediction of the ammonia probes of a variable proton-to-electron mass ratio

    NASA Astrophysics Data System (ADS)

    Owens, A.; Yurchenko, S. N.; Thiel, W.; Špirko, V.

    2015-07-01

    A comprehensive study of the mass sensitivity of the vibration-rotation-inversion transitions of 14NH3, 15NH3, 14ND3 and 15ND3 is carried out variationally using the TROVE approach. Variational calculations are robust and accurate, offering a new way to compute sensitivity coefficients. Particular attention is paid to the ?k = ±3 transitions between the accidentally coinciding rotation-inversion energy levels of the ?2 = 0+, 0-, 1+ and 1- states, and the inversion transitions in the ?4 = 1 state affected by the `giant' l-type doubling effect. These transitions exhibit highly anomalous sensitivities, thus appearing as promising probes of a possible cosmological variation of the proton-to-electron mass ratio ?. Moreover, a simultaneous comparison of the calculated sensitivities reveals a sizeable isotopic dependence which could aid an exclusive ammonia detection.

  13. Variability of the water mass transports and fluxes in the eastern North Atlantic during 2001

    Microsoft Academic Search

    L. Barbero; M. González-Dávila; J. M. Santana-Casiano; M. Álvarez

    2010-01-01

    The water mass distribution in the eastern North Atlantic Ocean (39–45°N, 16–22°W) during 2001 was determined for the upper 2000 m within the frame of the French research program POMME, using an extended Optimum Multiparameter analysis which included both conservative and nonconservative tracers. The presence of eastern North Atlantic Central Water in its subtropical and subpolar branches, Mediterranean Water, and

  14. An independent limit on the axion mass from the variable white dwarf star R548

    SciTech Connect

    Córsico, A.H.; Althaus, L.G. [Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del Bosque s/n, (1900) La Plata (Argentina); Romero, A.D.; Kepler, S.O. [Departamento de Astronomia, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, Porto Alegre 91501-970, RS (Brazil); Mukadam, A.S. [Department of Astronomy, University of Washington, Seattle, WA 98195-1580 (United States); García-Berro, E. [Departament de Física Aplicada, Universitat Politècnica de Catalunya, c/Esteve Terrades 5, 08860 Castelldefels (Spain); Isern, J. [Institut de Ciències de l'Espai (CSIC), Campus UAB, 08193 Bellaterra (Spain); Corti, M.A., E-mail: acorsico@fcaglp.unlp.edu.ar, E-mail: althaus@fcaglp.unlp.edu.ar, E-mail: aromero@fcaglp.unlp.edu.ar, E-mail: anjum@astro.washington.edu, E-mail: enrique.garcia-berro@upc.edu, E-mail: isern@ice.cat, E-mail: kepler@if.ufrgs.br, E-mail: mariela@fcaglp.fcaglp.unlp.edu.ar [Instituto Argentino de Radioastronomía (CCT-La Plata, CONICET), C.C. No. 5, 1894 Villa Elisa (Argentina)

    2012-12-01

    Pulsating white dwarfs with hydrogen-rich atmospheres, also known as DAV stars, can be used as astrophysical laboratories to constrain the properties of fundamental particles like axions. Comparing the measured cooling rates of these stars with the expected values from theoretical models allows us to search for sources of additional cooling due to the emission of weakly interacting particles. In this paper, we present an independent inference of the mass of the axion using the recent determination of the evolutionary cooling rate of R548, the DAV class prototype. We employ a state-of-the-art code which allows us to perform a detailed asteroseismological fit based on fully evolutionary sequences. Stellar cooling is the solely responsible of the rates of change of period with time (.?)) for the DAV class. Thus, the inclusion of axion emission in these sequences notably influences the evolutionary timescales, and also the expected pulsational properties of the DAV stars. This allows us to compare the theoretical .?) values to the corresponding empirical rate of change of period with time of R548 to discern the presence of axion cooling. We found that if the dominant period at 213.13 s in R548 is associated with a pulsation mode trapped in the hydrogen envelope, our models indicate the existence of additional cooling in this pulsating white dwarf, consistent with axions of mass m{sub a}cos {sup 2}? ? 17.1 meV at a 2? confidence level. This determination is in agreement with the value inferred from another well-studied DAV, G117-B15A. We now have two independent and consistent estimates of the mass of the axion obtained from DAVs, although additional studies of other pulsating white dwarfs are needed to confirm this value of the axion mass.

  15. An independent limit on the axion mass from the variable white dwarf star R548

    E-print Network

    Alejandro H. Córsico; Leandro G. Althaus; Alejandra D. Romero; Anjum S. Mukadam; Enrique García--Berro; Jordi Isern; S. O. Kepler; Mariela A. Corti

    2012-11-14

    Pulsating white dwarfs with hydrogen-rich atmospheres, also known as DAV stars, can be used as astrophysical laboratories to constrain the properties of fundamental particles like axions. Comparing the measured cooling rates of these stars with the expected values from theoretical models allows us to search for sources of additional cooling due to the emission of weakly interacting particles. In this paper, we present an independent inference of the mass of the axion using the recent determination of the evolutionary cooling rate of R548, the DAV class prototype. We employ a state-of-the-art code which allows us to perform a detailed asteroseismological fit based on fully evolutionary sequences. Stellar cooling is the solely responsible of the rates of change of period with time ($\\dot\\Pi$) for the DAV class. Thus, the inclusion of axion emission in these sequences notably influences the evolutionary timescales, and also the expected pulsational properties of the DAV stars. This allows us to compare the theoretical $\\dot\\Pi$ values to the corresponding empirical rate of change of period with time of R548 to discern the presence of axion cooling. We found that if the dominant period at 213.13 s in R548 is associated with a pulsation mode trapped in the hydrogen envelope, our models indicate the existence of additional cooling in this pulsating white dwarf, consistent with axions of mass $m_{\\rm a} \\cos^2 \\beta \\sim 17.1$ meV at a 2$\\sigma$ confidence level. This determination is in agreement with the value inferred from another well-studied DAV, G117$-$B15A. We now have two independent and consistent estimates of the mass of the axion obtained from DAVs, although additional studies of other pulsating white dwarfs are needed to confirm this value of the axion mass.

  16. Flow of variably fluidized granular masses across three-dimensional terrain 1. Coulomb mixture theory

    Microsoft Academic Search

    Richard M. Iverson; Roger P. Denlinger

    2001-01-01

    Rock avalanches, debris flows, and related phenomena consist of grain-fluid mixtures that move across three-dimensional terrain. In all these phenomena the same basic forces govern motion, but differing mixture compositions, initial conditions, and boundary conditions yield varied dynamics and deposits. To predict motion of diverse grain-fluid masses from initiation to deposition, we develop a depth-averaged, three- dimensional mathematical model that

  17. Improved methods for observing Earth's time variable mass distribution with GRACE using spherical cap mascons

    NASA Astrophysics Data System (ADS)

    Watkins, Michael M.; Wiese, David N.; Yuan, Dah-Ning; Boening, Carmen; Landerer, Felix W.

    2015-04-01

    We discuss several classes of improvements to gravity solutions from the Gravity Recovery and Climate Experiment (GRACE) mission. These include both improvements in background geophysical models and orbital parameterization leading to the unconstrained spherical harmonic solution JPL RL05, and an alternate JPL RL05M mass concentration (mascon) solution benefitting from those same improvements but derived in surface spherical cap mascons. The mascon basis functions allow for convenient application of a priori information derived from near-global geophysical models to prevent striping in the solutions. The resulting mass flux solutions are shown to suffer less from leakage errors than harmonic solutions, and do not necessitate empirical filters to remove north-south stripes, lowering the dependence on using scale factors (the global mean scale factor decreases by 0.17) to gain accurate mass estimates. Ocean bottom pressure (OBP) time series derived from the mascon solutions are shown to have greater correlation with in situ data than do spherical harmonic solutions (increase in correlation coefficient of 0.08 globally), particularly in low-latitude regions with small signal power (increase in correlation coefficient of 0.35 regionally), in addition to reducing the error RMS with respect to the in situ data (reduction of 0.37 cm globally, and as much as 1 cm regionally). Greenland and Antarctica mass balance estimates derived from the mascon solutions agree within formal uncertainties with previously published results. Computing basin averages for hydrology applications shows general agreement between harmonic and mascon solutions for large basins; however, mascon solutions typically have greater resolution for smaller spatial regions, in particular when studying secular signals.

  18. Accurate Prediction of the Ammonia Probes of a Variable Proton-to-Electron Mass Ratio

    E-print Network

    Owens, Alec; Thiel, Walter; Špirko, Vladimir

    2015-01-01

    A comprehensive study of the mass sensitivity of the vibration-rotation-inversion transitions of $^{14}$NH$_3$, $^{15}$NH$_3$, $^{14}$ND$_3$, and $^{15}$ND$_3$ is carried out variationally using the TROVE approach. Variational calculations are robust and accurate, offering a new way to compute sensitivity coefficients. Particular attention is paid to the $\\Delta k=\\pm 3$ transitions between the accidentally coinciding rotation-inversion energy levels of the $\

  19. 23 CFR 810.308 - Approval of urban system nonhighway public mass transit projects.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...Approval of urban system nonhighway public mass transit projects. 810.308 Section...TRANSPORTATION PUBLIC TRANSPORTATION MASS TRANSIT AND SPECIAL USE HIGHWAY PROJECTS...Federal-Aid Urban System Nonhighway Public Mass Transit Projects § 810.308...

  20. 23 CFR 810.308 - Approval of urban system nonhighway public mass transit projects.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...Approval of urban system nonhighway public mass transit projects. 810.308 Section...TRANSPORTATION PUBLIC TRANSPORTATION MASS TRANSIT AND SPECIAL USE HIGHWAY PROJECTS...Federal-Aid Urban System Nonhighway Public Mass Transit Projects § 810.308...

  1. 23 CFR 810.308 - Approval of urban system nonhighway public mass transit projects.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...Approval of urban system nonhighway public mass transit projects. 810.308 Section...TRANSPORTATION PUBLIC TRANSPORTATION MASS TRANSIT AND SPECIAL USE HIGHWAY PROJECTS...Federal-Aid Urban System Nonhighway Public Mass Transit Projects § 810.308...

  2. 23 CFR 810.308 - Approval of urban system nonhighway public mass transit projects.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...system nonhighway public mass transit projects. 810.308 Section 810.308 ...MASS TRANSIT AND SPECIAL USE HIGHWAY PROJECTS Federal-Aid Urban System Nonhighway Public Mass Transit Projects § 810.308 Approval of urban...

  3. 23 CFR 810.308 - Approval of urban system nonhighway public mass transit projects.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...system nonhighway public mass transit projects. 810.308 Section 810.308 ...MASS TRANSIT AND SPECIAL USE HIGHWAY PROJECTS Federal-Aid Urban System Nonhighway Public Mass Transit Projects § 810.308 Approval of urban...

  4. EJB-MVC oriented supplier selection system for mass customization

    Microsoft Academic Search

    Jiachen Hou; Daizhong Su

    2007-01-01

    Purpose – The purpose of this research is to develop a distributed system with an innovative supplier selection approach within a mass customization (MC) environment. The aim is to help manufacturers to identify appropriate suppliers for the components, materials and services required within the procedure of product design and manufacture. Design\\/methodology\\/approach – To identify the barriers for the supplier selection

  5. A Simple Mass Storage System for the SRB Data Grid

    Microsoft Academic Search

    Michael Wan; Arcot Rajasekar; Reagan Moore; Phil Andrews

    2003-01-01

    The functionality that is provided by Mass Storage Systems can be implemented using data grid technology. Data grids already provide many of the required features, including a logical name space and a storage repository abstraction. We demonstrate how management of tape resources can be integrated into data grids. The resulting infrastructure has the ability to manage archival storage of digital

  6. Dual Source Mass Spectrometer and Sample Handling System

    NASA Technical Reports Server (NTRS)

    Brinckerhoff, W. B.; Mahaffy, P. R.; Cornish, T. J.; Cheng, A. F.; Niemann, H. B.; Harpold, D. N.; Gorevan, S. P.; Rafeek, S.; Yucht, D.

    2002-01-01

    We present details of a miniature integrated time-of-flight mass spectrometer and sample handling system under development to address some of the needs for in situ sample analysis on landed missions. Additional information is contained in the original extended abstract.

  7. Estimation of convective mass transfer in solar distillation systems

    Microsoft Academic Search

    Sanjay Kumar; G. N. Tiwari

    1996-01-01

    In this article a thermal model has been developed to determine the convective mass transfer for different Grashof Number range in solar distillatiOn process. The model is based on simple regression analysis. Based on the experimental data obtained from the rigorous outdoor experimentation on passive and active distillation systems for summer climatic conditions, the values of C and n have

  8. Higgs mass as a signature of chaos in YMH system

    NASA Astrophysics Data System (ADS)

    Dobrowolski, T.; Szcz?sny, J.

    2000-07-01

    Sector of the Yang-Mills-Higgs (YMH) system containing spherically symmetric solutions is considered. It is found in the framework of the geodesic deviation equation that Higgs mass is a natural indicator of the presence of the sensitive dependence on initial conditions in the model.

  9. Control System for an Ion Trap Mass Spectrometer

    Microsoft Academic Search

    Derek F. Hopkins; M. Lizabeth Alexander; Ken R. Swanson; Michael A. Buschbach

    2004-01-01

    This paper describes the development of a control system for an ion trap mass spectrometer that is both inexpensive and flexible, allowing application of ion trap technology to a number of research areas. This project is part of the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL), a U.S. Department of Energy national scientific user facility, located at Pacific Northwest

  10. MALDI imaging mass spectrometry: molecular snapshots of biochemical systems

    E-print Network

    Cai, Long

    MALDI imaging mass spectrometry: molecular snapshots of biochemical systems Dale S Cornett, Michelle L Reyzer, Pierre Chaurand & Richard M Caprioli Matrix-assisted laser desorption/ionization (MALDI imaging methods, MALDI-IMS can determine the distribution of hundreds of unknown compounds in a single

  11. Clumped stellar winds in supergiant high-mass X-ray binaries: X-ray variability and photoionization

    NASA Astrophysics Data System (ADS)

    Oskinova, L. M.; Feldmeier, A.; Kretschmar, P.

    2012-04-01

    The clumping of massive star winds is an established paradigm, which is confirmed by multiple lines of evidence and is supported by stellar wind theory. The purpose of this paper is to bridge the gap between detailed models of inhomogeneous stellar winds in single stars and the phenomenological description of donor winds in supergiant high-mass X-ray binaries (HMXBs). We use the results from time-dependent hydrodynamical models of the instability in the line-driven wind of a massive supergiant star to derive the time-dependent accretion rate on to a compact object in the Bondi-Hoyle-Lyttleton approximation. The strong density and velocity fluctuations in the wind result in strong variability of the synthetic X-ray light curves. The model predicts a large-scale X-ray variability, up to eight orders of magnitude, on relatively short time-scales. The apparent lack of evidence for such strong variability in the observed HMXBs indicates that the details of the accretion process act to reduce the variability resulting from the stellar wind velocity and density jumps. We study the absorption of X-rays in the clumped stellar wind by means of a two-dimensional stochastic wind model. The monochromatic absorption in the cool stellar wind, depending on the orbital phase, is computed for realistic stellar wind opacity. We find that the absorption of X-rays changes strongly at different orbital phases. The degree of the variability resulting from the absorption in the wind depends on the shape of the wind clumps, and this is stronger for oblate clumps. We address the photoionization in the clumped wind, and we show that the degree of ionization is affected by the wind clumping. We derive a correction factor for the photoionization parameter, and we show that the photoionization parameter is reduced by a factor ? compared to the smooth wind models with the same mass-loss rate, where ? is the wind inhomogeneity parameter. We conclude that wind clumping must also be taken into account when comparing the observed and model spectra of the photoionized stellar wind.

  12. Petroleomics by electrospray ionization FT-ICR mass spectrometry coupled to partial least squares with variable selection methods: prediction of the total acid number of crude oils.

    PubMed

    Terra, Luciana A; Filgueiras, Paulo R; Tose, Lílian V; Romão, Wanderson; de Souza, Douglas D; de Castro, Eustáquio V R; de Oliveira, Mirela S L; Dias, Júlio C M; Poppi, Ronei J

    2014-10-01

    Negative-ion mode electrospray ionization, ESI(-), with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was coupled to a Partial Least Squares (PLS) regression and variable selection methods to estimate the total acid number (TAN) of Brazilian crude oil samples. Generally, ESI(-)-FT-ICR mass spectra present a power of resolution of ca. 500,000 and a mass accuracy less than 1 ppm, producing a data matrix containing over 5700 variables per sample. These variables correspond to heteroatom-containing species detected as deprotonated molecules, [M - H](-) ions, which are identified primarily as naphthenic acids, phenols and carbazole analog species. The TAN values for all samples ranged from 0.06 to 3.61 mg of KOH g(-1). To facilitate the spectral interpretation, three methods of variable selection were studied: variable importance in the projection (VIP), interval partial least squares (iPLS) and elimination of uninformative variables (UVE). The UVE method seems to be more appropriate for selecting important variables, reducing the dimension of the variables to 183 and producing a root mean square error of prediction of 0.32 mg of KOH g(-1). By reducing the size of the data, it was possible to relate the selected variables with their corresponding molecular formulas, thus identifying the main chemical species responsible for the TAN values. PMID:25068148

  13. The young low-mass star ISO-Oph-50: extreme variability induced by a clumpy, evolving circumstellar disc

    NASA Astrophysics Data System (ADS)

    Scholz, Alexander; Muži?, Koraljka; Geers, Vincent

    2015-07-01

    ISO-Oph-50 is a young low-mass object in the ˜1 Myr old Ophiuchus star-forming region undergoing dramatic changes in its optical/near/mid-infrared brightness by 2-4 mag. We present new multi-band photometry and near-infrared spectra, combined with a synopsis of the existing literature data. Based on the spectroscopy, the source is confirmed as a mid-M dwarf, with evidence for ongoing accretion. The near-infrared light curves show large-scale variations, with 2-4 mag amplitude in the bands IJHK, with the object generally being bluer when faint. Near its brightest state, the object shows colour changes consistent with variable extinction of ?AV ˜ 7 mag. High-cadence monitoring at 3.6 ?m reveals quasi-periodic variations with a typical time-scale of 1-2 weeks. The best explanation for these characteristics is a low-mass star seen through circumstellar matter, whose complex variability is caused by changing inhomogeneities in the inner parts of the disc. When faint, the direct stellar emission is blocked; the near-infrared radiation is dominated by scattered light. When bright, the emission is consistent with a photosphere strongly reddened by circumstellar dust. Based on the available constraints, the inhomogeneities have to be located at or beyond ˜0.1 au distance from the star. If this scenario turns out to be correct, a major portion of the inner disc has to be clumpy, structured, and/or in turmoil. In its observational characteristics, this object resembles other types of young stellar objects with variability caused in the inner disc. Compared to other objects, however, ISO-Oph-50 is clearly an extreme case, given the large amplitude of the brightness and colour changes combined with the erratic behaviour. ISO-Oph-50 has been near its brightest state since 2013; further monitoring is highly encouraged.

  14. Nevada Monitoring System to Assess Climate Variability and Change

    NASA Astrophysics Data System (ADS)

    Devitt, D. A.; Arnone, J.; Biondi, F.; Fenstermaker, L. F.; Saito, L.; Young, M.; Riddle, B.; Strachan, S. D.; Bird, B.; McCurdy, G.; Lyles, B. F.

    2010-12-01

    The Nevada System of Higher Education (University of Nevada Las Vegas, University of Nevada Reno and the Desert Research Institute) was awarded a multiyear NSF EPSCoR grant to support infrastructure associated with regional climate change research. The overall project is comprised of 5 components: education, cyberinfrastructure, policy, climate modeling and water/ecology. The water and ecology components are using their infrastructure funding for the assessment of climate variability and change on ecosystem function and hydrologic services. A series of 10 m tall towers are under construction and are being equipped with a wide array of sensors to monitor atmospheric, soil and plant parameters over time. The towers are located within the Mojave and Great Basin Deserts in two transects; the Mojave Desert transect is located in the southern Nevada Sheep Mountain Range and the Great Basin transect is located in the east central Nevada Snake Mountain Range. The towers are centrally positioned in well-defined vegetation zones. In southern Nevada these zones are represented by the following plant species: Creosote/Bursage (Creosotebush scrub zone); Blackbrush/Joshua Tree (Blackbrush zone); Pinyon/ Juniper (pygmy conifer zone), Ponderosa Pine (montane zone) and Bristlecone Pine (subalpine zone). The Snake Mountain transect incorporates the eastern and western valleys on both sides of the mountain range. The vegetation zones are represented by: Greasewood and mixed shrub (salt desert zone); Big Sage (sagebrush zone); Pinyon/Juniper (pygmy conifer zone); White/Douglas Fir, Ponderosa Pine and Aspen (montane zone); and Bristlecone/Limber Pine and Engelmann Spruce (subalpine zone). We are currently in the third year of funding with a goal of having the majority of towers fully operational by winter 2010. In close collaboration with our cyberinfrastructure component team, all data acquired from the transect monitoring stations will be made available to other researchers and the public in Nevada and elsewhere, cooperating agencies and organizations, and State of Nevada land managers.

  15. Improved orbital solution and masses for the very low-mass multiple system LHS 1070

    E-print Network

    A. Seifahrt; T. Roell; R. Neuhaeuser; A. Reiners; F. Kerber; H. U. Kaeufl; R. Siebenmorgen; A. Smette

    2008-06-04

    We present a refined orbital solution for the components A, B, and C of the nearby late-M type multiple system LHS 1070. By combining astrometric datapoints from NACO/VLT, CIAO/SUBARU, and PUEO/CFHT, as well as a radial velocity measurement from the newly commissioned near infrared high-resolution spectrograph CRIRES/VLT, we achieve a very precise orbital solution for the B and C components and a first realistic constraint on the much longer orbit of the A-BC system. Both orbits appear to be co-planar. Masses for the B and C components calculated from the new orbital solution (M_(B+C) = 0.157 +/- 0.009 M_sun) are in excellent agreement with theoretical models, but do not match empirical mass-luminosity tracks. The preliminary orbit of the A-BC system reveals no mass excess for the A component, giving no indication for a previously proposed fourth (D) component in LHS 1070.

  16. Structure and evolution of low mass W UMa type systems

    E-print Network

    Lifang Li; Zhanwen Han; Fenghui Zhang

    2004-03-15

    The structure and evolution of low mass W UMa type contact binaries are discussed by employing Eggleton's stellar evolution code. Assuming that these systems completely satisfy Roche geometry, we calculate the relative radii of both components of contact binaries in different contact depth between inner and outer Roche lobes. We obtain a radius grid of contact binaries, and can ensure the surfaces of two components lying on an equipotential surface by interpolation using this radius grid when we follow the evolution of the contact binaries. We assume that the energy transfer takes place in the different regions of the common envelope to investigate the effects of the region of energy transfer on the structure and evolution of contact binaries. We find that the region of energy transfer has significant influence on the structure and evolution of contact binaries, and conclude that the energy transfer may occur in the outermost layers of the common convective envelope for W-type systems, and this transfer takes place in the deeper layers of the common envelope for A-type systems. Meanwhile, if we assume that the energy transfer takes place in the outermost layers for our model with low total mass, and find that our model steadily evolves towards a system with a smaller mass ratio and a deeper envelope, suggesting that some A-type W UMa systems with low total mass could be considered as the later evolutionary stages of W-subtype systems, and that the surface temperature of the secondary excesses that of the primary during the time when the primary expands rapidly, or the secondary contracts rapidly, suggesting that W-subtype systems may be caused by expansion of the primary, or by the contraction of the secondary.

  17. Constraining Aerosol Optical Models Using Ground-Based, Collocated Particle Size and Mass Measurements in Variable Air Mass Regimes During the 7-SEAS/Dongsha Experiment

    NASA Technical Reports Server (NTRS)

    Bell, Shaun W.; Hansell, Richard A.; Chow, Judith C.; Tsay, Si-Chee; Wang, Sheng-Hsiang; Ji, Qiang; Li, Can; Watson, John G.; Khlystov, Andrey

    2012-01-01

    During the spring of 2010, NASA Goddard's COMMIT ground-based mobile laboratory was stationed on Dongsha Island off the southwest coast of Taiwan, in preparation for the upcoming 2012 7-SEAS field campaign. The measurement period offered a unique opportunity for conducting detailed investigations of the optical properties of aerosols associated with different air mass regimes including background maritime and those contaminated by anthropogenic air pollution and mineral dust. What appears to be the first time for this region, a shortwave optical closure experiment for both scattering and absorption was attempted over a 12-day period during which aerosols exhibited the most change. Constraints to the optical model included combined SMPS and APS number concentration data for a continuum of fine and coarse-mode particle sizes up to PM2.5. We also take advantage of an IMPROVE chemical sampler to help constrain aerosol composition and mass partitioning of key elemental species including sea-salt, particulate organic matter, soil, non sea-salt sulphate, nitrate, and elemental carbon. Our results demonstrate that the observed aerosol scattering and absorption for these diverse air masses are reasonably captured by the model, where peak aerosol events and transitions between key aerosols types are evident. Signatures of heavy polluted aerosol composed mostly of ammonium and non sea-salt sulphate mixed with some dust with transitions to background sea-salt conditions are apparent in the absorption data, which is particularly reassuring owing to the large variability in the imaginary component of the refractive indices. Extinctive features at significantly smaller time scales than the one-day sample period of IMPROVE are more difficult to reproduce, as this requires further knowledge concerning the source apportionment of major chemical components in the model. Consistency between the measured and modeled optical parameters serves as an important link for advancing remote sensing and climate research studies in dynamic aerosol-rich environments like Dongsha.

  18. Groundwater mass transport and equilibrium chemistry model for multicomponent systems

    SciTech Connect

    Cederberg, G.A.; Street, R.L.; Leckie, J.O.

    1985-01-01

    A mass-transport model, TRANQL, for a multicomponent solution system was developed. The equilibrium interaction chemistry is posed independently of the mass-transport equations which leads to a set of algebraic equations for the chemistry coupled to a set of differential equations for the mass transport. Significant equilibrium chemical reactions such as complexation, ion exchange, competitive adsorption, and dissociation of water may be included in TRANQL. Here, a finite element solution is presented first for cadmium, chloride, and bromide transport in a one-dimensional column where complexation and sorption are considered. Second, binary and ternary ion exchange are modeled and compared to the results of other investigators. (Copyright (c) 1985 by the American Geophysical Union.)

  19. Mass independent kinetic energy reducing inlet system for vacuum environment

    DOEpatents

    Reilly, Peter T.A.

    2014-05-13

    A particle inlet system comprises a first chamber having a limiting orifice for an incoming gas stream and a micrometer controlled expansion slit. Lateral components of the momentum of the particles are substantially cancelled due to symmetry of the configuration once the laminar flow converges at the expansion slit. The particles and flow into a second chamber, which is maintained at a lower pressure than the first chamber, and then moves into a third chamber including multipole guides for electromagnetically confining the particle. The vertical momentum of the particles descending through the center of the third chamber is minimized as an upward stream of gases reduces the downward momentum of the particles. The translational kinetic energy of the particles is near-zero irrespective of the mass of the particles at an exit opening of the third chamber, which may be advantageously employed to provide enhanced mass resolution in mass spectrometry.

  20. Mass independent kinetic energy reducing inlet system for vacuum environment

    DOEpatents

    Reilly, Peter T. A. [Knoxville, TN

    2010-12-14

    A particle inlet system comprises a first chamber having a limiting orifice for an incoming gas stream and a micrometer controlled expansion slit. Lateral components of the momentum of the particles are substantially cancelled due to symmetry of the configuration once the laminar flow converges at the expansion slit. The particles and flow into a second chamber, which is maintained at a lower pressure than the first chamber, and then moves into a third chamber including multipole guides for electromagnetically confining the particle. The vertical momentum of the particles descending through the center of the third chamber is minimized as an upward stream of gases reduces the downward momentum of the particles. The translational kinetic energy of the particles is near-zero irrespective of the mass of the particles at an exit opening of the third chamber, which may be advantageously employed to provide enhanced mass resolution in mass spectrometry.

  1. Mass independent kinetic energy reducing inlet system for vacuum environment

    DOEpatents

    Reilly, Peter T.A.

    2013-12-03

    A particle inlet system comprises a first chamber having a limiting orifice for an incoming gas stream and a micrometer controlled expansion slit. Lateral components of the momentum of the particles are substantially cancelled due to symmetry of the configuration once the laminar flow converges at the expansion slit. The particles and flow into a second chamber, which is maintained at a lower pressure than the first chamber, and then moves into a third chamber including multipole guides for electromagnetically confining the particle. The vertical momentum of the particles descending through the center of the third chamber is minimized as an upward stream of gases reduces the downward momentum of the particles. The translational kinetic energy of the particles is near-zero irrespective of the mass of the particles at an exit opening of the third chamber, which may be advantageously employed to provide enhanced mass resolution in mass spectrometry.

  2. Probing the geometric nature of particles mass in graphene systems

    E-print Network

    Dolce, Donatello

    2014-01-01

    According to undulatory mechanics, the Compton periodicity, which is the intrinsic proper-time recurrence of a wave function, determines the mass of the corresponding elementary particles. This provides a geometric description of the rest mass which can be consistently applied to derive the effective mass spectrum and electronic properties of the elementary charge carriers in carbon nanotubes and other condensed matter systems. The Compton periodicity is determined by the boundary conditions associated to the curled-up dimension of carbon nanotubes or analogous constraints of the charge carrier wave function. This approach shows an interesting interplay between particle physics and relativistic space-time, as well as analogies with the Kaluza-Klein theory and Holography.

  3. Factors influencing variability in the infiltration of PM2.5 mass and its components

    NASA Astrophysics Data System (ADS)

    MacNeill, M.; Wallace, L.; Kearney, J.; Allen, R. W.; Van Ryswyk, K.; Judek, S.; Xu, X.; Wheeler, A.

    2012-12-01

    The infiltration of particles into homes can vary seasonally, between homes in a community and between communities. However, few studies have examined the day to day variability across multiple homes. We used continuous data collected from a 2-year (2005-2006) personal exposure study conducted in Windsor, ON to estimate daily infiltration factors (Finf) for fine particulate matter (PM2.5), Black Carbon (BC), and ultrafine particles (UFP) as well as the ambient personal exposure factor (Fpex) for PM2.5. In addition, the daily ambient and non-ambient generated components of indoor and personal concentrations were estimated. Median daily Finf estimates ranged from 0.26 to 0.36 across seasons for PM2.5; from 0.28 to 0.59 for BC; and from 0.15 to 0.26 for UFP. Median daily Fpex estimates ranged from 0.24 to 0.31 across seasons. Daily PM2.5 and UFP Finf and Fpex estimates were higher in summer than winter, although BC showed the opposite trend. Predictors of daily infiltration were typically related to window-opening behaviours, air conditioning, meteorological variables, and home age. In addition, use of electrostatic precipitators and stand alone air cleaners was associated with significantly reduced infiltration factors, indicating that these devices may provide a cost effective mechanism of reducing human exposures to particles of ambient origin. The majority of indoor PM2.5 (median 57-73%) and indoor BC (median 90-100%) was of ambient origin across seasons, while both personal PM2.5 and indoor UFPs had significant non-ambient contributions (median 60-65%). Factors that were found to increase non-ambient particle concentrations were typically related to cooking, candle use, supplemental heating, cleaning, and number of people in the home. Factors that were found to decrease non-ambient particle concentrations were open windows, and air cleaner use. This work has several implications to both epidemiologic studies and risk management. A better understanding of the factors influencing Finf and Fpex can improve exposure assessment and contribute to reduced exposure misclassification in epidemiologic studies. Furthermore, by increasing our knowledge of non-ambient and ambient exposures, risk associated with PM exposure can be managed more effectively.

  4. Noise Levels Associated With New York City's Mass Transit Systems

    PubMed Central

    Gershon, Robyn R. M.; Zeltser, Marina; Canton, Allison; Akram, Muhammad

    2009-01-01

    Objectives. We measured noise levels associated with various forms of mass transit and compared them to exposure guidelines designed to protect against noise-induced hearing loss. Methods. We used noise dosimetry to measure time-integrated noise levels in a representative sample of New York City mass transit systems (subways, buses, ferries, tramway, and commuter railways) aboard transit vehicles and at vehicle boarding platforms or terminals during June and July 2007. Results. Of the transit types evaluated, subway cars and platforms had the highest associated equivalent continuous average (Leq) and maximum noise levels. All transit types had Leq levels appreciably above 70 A-weighted decibels, the threshold at which noise-induced hearing loss is considered possible. Conclusions. Mass transit noise exposure has the potential to exceed limits recommended by the World Health Organization and the US Environmental Protection Agency and thus cause noise-induced hearing loss among riders of all forms of mass transit given sufficient exposure durations. Environmental noise–control efforts in mass transit and, in cases in which controls are infeasible, the use of personal hearing protection would benefit the ridership's hearing health. PMID:19542046

  5. Research of variable frequency control technology for heavy adjustor in power plant fuel system

    Microsoft Academic Search

    Chongsheng Hou

    2011-01-01

    Traditional run way of the heavy adjustor in thermal power plant fuel system and its creation to influence badly is carefully investigated. Based on run characteristics of heavy adjustor, technology scheme that traditional run mode is improved by PLC as central controller and variable frequency control technology is deeply studied, variable frequency control system and electricity reformation circuit is designed,

  6. Delay Identification in Time-Delay Systems using Variable Structure Observers

    E-print Network

    Paris-Sud XI, Université de

    Delay Identification in Time-Delay Systems using Variable Structure Observers S. V. Drakunov , W. Perruquetti, J.-P. Richard , L. Belkoura Abstract In this paper we discuss delay estimation in time-delay based on variable structure observers. 1 Introduction Numerous researches involve time-delay systems

  7. Scalability and Performance Improvements in the Fermilab Mass Storage System

    NASA Astrophysics Data System (ADS)

    Crawford, Matt; Dumitrescu, Catalin; Litvintsev, Dmitry; Moibenko, Alexander; Oleynik, Gene

    2012-12-01

    By 2009 the Fermilab Mass Storage System had encountered two major challenges: the required amount of data stored and accessed in both tiers of the system (dCache and Enstore) had significantly increased and the number of clients accessing Mass Storage System had increased from tens to hundreds of nodes and from hundreds to thousands of parallel requests. To address these challenges Enstore and the SRM part of dCache were modified to scale for performance, access rates, and capacity. This work increased the amount of simultaneously processed requests in a single Enstore Library instance from about 1000 to 30000. The rates of incoming requests to Enstore increased from tens to hundreds per second. Fermilab is invested in LTO4 tape technology and we have investigated both LTO5 and Oracle T10000C to cope with the increasing needs in capacity. We have decided to adopt T10000C, mainly due to its large capacity, which allows us to scale up the existing robotic storage space by a factor 6. This paper describes the modifications and investigations that allowed us to meet these scalability and performance challenges and provided some perspectives of Fermilab Mass Storage System.

  8. On the Inversion for Mass (Re)Distribution from Global (Time-Variable) Gravity Field

    NASA Technical Reports Server (NTRS)

    Chao, Benjamin F.

    2004-01-01

    The well-known non-uniqueness of the gravitational inverse problem states the following: The external gravity field, even if completely and exactly known, cannot Uniquely determine the density distribution of the body that produces the gravity field. This is an intrinsic property of a field that obeys the Laplace equation, as already treated in mathematical as well as geophysical literature. In this paper we provide conceptual insight by examining the problem in terms of spherical harmonic expansion of the global gravity field. By comparing the multipoles and the moments of the density function, we show that in 3-S the degree of knowledge deficiency in trying to inversely recover the density distribution from external gravity field is (n+l)(n+2)/2 - (2n+l) = n(n-1)/2 for each harmonic degree n. On the other hand, on a 2-D spherical shell we show via a simple relationship that the inverse solution of the surface density distribution is unique. The latter applies quite readily in the inversion of time-variable gravity signals (such as those observed by the GRACE space mission) where the sources over a wide range of the scales largely come from the Earth's Surface.

  9. A Body Shape Index and Heart Rate Variability in Healthy Indians with Low Body Mass Index

    PubMed Central

    Thomas, Tinku; Bharathi, Ankalmadagu Venkatsubbareddy; Sucharita, Sambashivaiah

    2014-01-01

    Background. One third of Indian population is said to be suffering from chronic energy deficiency (CED), with increased risk of developing chronic diseases. A new anthropometric measure called A Body Shape Index (ABSI) is said to be a better index in predicting risks for premature mortality. ABSI is also in part said to be a surrogate of visceral fat. Objective. The present study aimed to explore the association between indices of HRV (heart rate variability), BMI, WC, and ABSI in healthy Indian males with low BMI (BMI < 18.5?kg/m2) and to compare with normal BMI group (BMI 18.5 to 24.9?kg/m2). Methodology. ABSI and BMI were derived from anthropometric parameters, namely, height, weight, and waist circumference in 178 males aged 18 to 78 years. Subjects were categorized into two groups based on their BMI. Results and Conclusions. Power spectral analysis of HRV demonstrated a significant negative correlation between Log HF (high frequency) and ABSI in both low BMI [?24.2 (9.4), P < 0.05] and normal BMI group [?23.41 (10.1), P < 0.05] even after controlling for age. Thus even with slight increase in BMI among low BMI individuals, there could be a greater risk of cardiovascular morbidity and mortality. PMID:25371818

  10. The Effect of Pressure Difference Control on Hydraulic Stability in a Variable Flow Air Conditioning System 

    E-print Network

    Zhang, Z.; Fu, Y.; Chen, Y.

    2006-01-01

    ICEBO2006, Shenzhen, China Control Systems for Energy Efficiency and Comfort, Vol. V-4-3 The Effect of Pressure Difference Control on Hydraulic Stability in a Variable Flow Air Conditioning System Zaipeng Zhang Yongzheng FU Yanhua...

  11. The Effect of Pressure Difference Control on Hydraulic Stability in a Variable Flow Air Conditioning System

    E-print Network

    Zhang, Z.; Fu, Y.; Chen, Y.

    2006-01-01

    This paper analyzes the effects of different pressure difference control methods on hydraulic stability in a variable flow air conditioning system when it is applied to different air conditioning water systems. According to control method and water...

  12. Variable Speed Drive (VSD) Applications in Dual-Duct Constant Volume Systems

    E-print Network

    Joo, I.; Liu, M.; Conger, K.; Wang, G.

    2002-01-01

    Models have been developed for static pressure and potential supply fan energy savings by using variable speed drive (VSD) in dual-duct constant volume systems. Experiments have been performed using a full size dual-duct constant volume system...

  13. Variable Speed Drive (VSD) Applications in Dual-Duct Constant Volume Systems 

    E-print Network

    Joo, I.; Liu, M.; Conger, K.; Wang, G.

    2002-01-01

    Models have been developed for static pressure and potential supply fan energy savings by using variable speed drive (VSD) in dual-duct constant volume systems. Experiments have been performed using a full size dual-duct constant volume system...

  14. A Unified Expression of Harada-Sasa Equality in Underdamped and Overdamped Langevin Systems of the Field Variable Description

    NASA Astrophysics Data System (ADS)

    Yamada, Kazuo; Yoshimori, Akira

    2015-04-01

    We extend the relationship between the fluctuation-response relation (FRR) violation and the stationary energy dissipation rate to the Langevin system expressed by field variable. We propose two methods for extending: the operator method and the multiple-scale analysis. By these methods, we expand the FRR violation for the underdamped field system in power series of ? = m/? to establish the relationship between underdamped and overdamped systems. Here, ? and m are the friction coefficient and mass of a Brownian particle, respectively. By the expansion, we obtain a unified expression including the relations in the underdamped and overdamped field systems as special cases. The expression shows that the relations have the same form in the underdamped and overdamped field systems. In addition, we show that the relation also holds in the time region difference from that in the underdamped or overdamped system.

  15. Fourth NASA Goddard Conference on Mass Storage Systems and Technologies

    NASA Technical Reports Server (NTRS)

    Kobler, Benjamin (editor); Hariharan, P. C. (editor)

    1994-01-01

    This report contains copies of all those technical papers received in time for publication just prior to the Fourth Goddard Conference on Mass Storage and Technologies, held March 28-30, 1995, at the University of Maryland, University College Conference Center, in College Park, Maryland. This series of conferences continues to serve as a unique medium for the exchange of information on topics relating to the ingestion and management of substantial amounts of data and the attendant problems involved. This year's discussion topics include new storage technology, stability of recorded media, performance studies, storage system solutions, the National Information infrastructure (Infobahn), the future for storage technology, and lessons learned from various projects. There also will be an update on the IEEE Mass Storage System Reference Model Version 5, on which the final vote was taken in July 1994.

  16. X-RAY DETERMINATION OF THE VARIABLE RATE OF MASS ACCRETION ONTO TW HYDRAE

    SciTech Connect

    Brickhouse, N. S.; Cranmer, S. R.; Dupree, A. K.; Guenther, H. M.; Wolk, S. J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Luna, G. J. M. [Current address: Instituto de Astronomia y Fisica del Espacio (IAFE), Buenos Aires (Argentina)

    2012-12-01

    Diagnostics of electron temperature (T{sub e} ), electron density (n{sub e} ), and hydrogen column density (N{sub H}) from the Chandra High Energy Transmission Grating spectrum of He-like Ne IX in TW Hydrae (TW Hya), in conjunction with a classical accretion model, allow us to infer the accretion rate onto the star directly from measurements of the accreting material. The new method introduces the use of the absorption of Ne IX lines as a measure of the column density of the intervening, accreting material. On average, the derived mass accretion rate for TW Hya is 1.5 Multiplication-Sign 10{sup -9} M{sub Sun} yr{sup -1}, for a stellar magnetic field strength of 600 G and a filling factor of 3.5%. Three individual Chandra exposures show statistically significant differences in the Ne IX line ratios, indicating changes in N{sub H}, T{sub e} , and n{sub e} by factors of 0.28, 1.6, and 1.3, respectively. In exposures separated by 2.7 days, the observations reported here suggest a five-fold reduction in the accretion rate. This powerful new technique promises to substantially improve our understanding of the accretion process in young stars.

  17. Variable Low-Mass X-ray Binaries in Early-Type Galaxies Gregory R. Sivakoff

    E-print Network

    Sarazin, Craig

    Paradijs 1996). In short-period systems (Porb sequence star, theory cycle, companion types (main- sequence, red giant, or white dwarf), and stellar age (e.g., Ivanova The detailed study of Galactic X-ray binaries (XRBs) has placed strong constraints on theories of XRB evolution

  18. MALDI imaging mass spectrometry: molecular snapshots of biochemical systems

    Microsoft Academic Search

    Dale S Cornett; Michelle L Reyzer; Pierre Chaurand; Richard M Caprioli

    2007-01-01

    Matrix-assisted laser desorption\\/ionization (MALDI) imaging mass spectrometry (IMS) is emerging as a powerful tool for investigating the distribution of molecules within biological systems through the direct analysis of thin tissue sections. Unique among imaging methods, MALDI-IMS can determine the distribution of hundreds of unknown compounds in a single measurement. We discuss the current state of the art of MALDI-IMS along

  19. Control system and method for a power delivery system having a continuously variable ratio transmission

    DOEpatents

    Frank, Andrew A. (1034 Hillside Ave., Madison, WI 53705)

    1984-01-01

    A control system and method for a power delivery system, such as in an automotive vehicle, having an engine coupled to a continuously variable ratio transmission (CVT). Totally independent control of engine and transmission enable the engine to precisely follow a desired operating characteristic, such as the ideal operating line for minimum fuel consumption. CVT ratio is controlled as a function of commanded power or torque and measured load, while engine fuel requirements (e.g., throttle position) are strictly a function of measured engine speed. Fuel requirements are therefore precisely adjusted in accordance with the ideal characteristic for any load placed on the engine.

  20. Control system and method for a power delivery system having a continuously variable ratio transmission

    DOEpatents

    Frank, A.A.

    1984-07-10

    A control system and method for a power delivery system, such as in an automotive vehicle, having an engine coupled to a continuously variable ratio transmission (CVT). Totally independent control of engine and transmission enable the engine to precisely follow a desired operating characteristic, such as the ideal operating line for minimum fuel consumption. CVT ratio is controlled as a function of commanded power or torque and measured load, while engine fuel requirements (e.g., throttle position) are strictly a function of measured engine speed. Fuel requirements are therefore precisely adjusted in accordance with the ideal characteristic for any load placed on the engine. 4 figs.

  1. Eighth Goddard Conference on Mass Storage Systems and Technologies in Cooperation with the Seventeenth IEEE Symposium on Mass Storage Systems

    NASA Technical Reports Server (NTRS)

    Kobler, Benjamin (Editor); Hariharan, P. C. (Editor)

    2000-01-01

    This document contains copies of those technical papers received in time for publication prior to the Eighth Goddard Conference on Mass Storage Systems and Technologies which is being held in cooperation with the Seventeenth IEEE Symposium on Mass Storage Systems at the University of Maryland University College Inn and Conference Center March 27-30, 2000. As one of an ongoing series, this Conference continues to provide a forum for discussion of issues relevant to the management of large volumes of data. The Conference encourages all interested organizations to discuss long term mass storage requirements and experiences in fielding solutions. Emphasis is on current and future practical solutions addressing issues in data management, storage systems and media, data acquisition, long term retention of data, and data distribution. This year's discussion topics include architecture, future of current technology, new technology with a special emphasis on holographic storage, performance, standards, site reports, vendor solutions. Tutorials will be available on stability of optical media, disk subsystem performance evaluation, I/O and storage tuning, functionality and performance evaluation of file systems for storage area networks.

  2. Periodic mass-loss episodes due to an oscillation mode with variable amplitude in the hot supergiant HD 50064

    NASA Astrophysics Data System (ADS)

    Aerts, C.; Lefever, K.; Baglin, A.; Degroote, P.; Oreiro, R.; Vu?kovi?, M.; Smolders, K.; Acke, B.; Verhoelst, T.; Desmet, M.; Godart, M.; Noels, A.; Dupret, M.-A.; Auvergne, M.; Baudin, F.; Catala, C.; Michel, E.; Samadi, R.

    2010-04-01

    Aims: We aim to interpret the photometric and spectroscopic variability of the luminous blue variable supergiant HD 50064 (V = 8.21). Methods: CoRoT space photometry and follow-up high-resolution spectroscopy with a time base of 137 d and 169 d, respectively, was gathered, analysed, and interpreted using standard time series analysis and light curve modelling methods, as well as spectral line diagnostics. Results: The space photometry reveals one period of 37 d, which undergoes a sudden amplitude change with a factor 1.6. The pulsation period is confirmed in the spectroscopy, which additionally reveals metal line radial velocity values differing by 30 km s-1 depending on the spectral line and on the epoch. We estimate Teff 13 500 K, log g 1.5 from the equivalent width of Si lines. The Balmer lines reveal that the star undergoes episodes of changing mass loss on a time scale similar to the changes in the photometric and spectroscopic variability, with an average value of log dot{M} ? -5 (in M_? yr-1). We tentatively interpret the 37 d period as the result of a strange mode oscillation. Based on high-resolution spectroscopy assembled with the CORALIE spectrograph attached to the 1.2 m Euler telescope at La Silla, Chile and on CoRoT space-based photometry. The CoRoT space mission was developed and is operated by the French space agency CNES, with the participation of ESA's RSSD and Science Programmes, Austria, Belgium, Brazil, Germany, and Spain.Postdoctoral Fellow of the Fund for Scientific Research of Flanders (FWO), Belgium.

  3. A mass storage system for supercomputers based on Unix

    NASA Technical Reports Server (NTRS)

    Richards, J.; Kummell, T.; Zarlengo, D. G.

    1988-01-01

    The authors present the design, implementation, and utilization of a large mass storage subsystem (MSS) for the numerical aerodynamics simulation. The MSS supports a large networked, multivendor Unix-based supercomputing facility. The MSS at Ames Research Center provides all processors on the numerical aerodynamics system processing network, from workstations to supercomputers, the ability to store large amounts of data in a highly accessible, long-term repository. The MSS uses Unix System V and is capable of storing hundreds of thousands of files ranging from a few bytes to 2 Gb in size.

  4. Cataclysmic Variables

    E-print Network

    Robert Connon Smith

    2007-01-23

    Cataclysmic variables are binary stars in which a relatively normal star is transferring mass to its compact companion. This interaction gives rise to a rich range of behaviour, of which the most noticeable are the outbursts that give the class its name. Novae belong to the class, as do the less well known dwarf novae and magnetic systems. Novae draw their energy from nuclear reactions, while dwarf novae rely on gravity to power their smaller eruptions. All the different classes of cataclysmic variable can be accommodated within a single framework and this article will describe the framework, review the properties of the main types of system and discuss models of the outbursts and of the long-term evolution.

  5. Flow of variably fluidized granular masses across three-dimensional terrain I. Coulomb mixture theory

    USGS Publications Warehouse

    Iverson, R.M.; Denlinger, R.P.

    2001-01-01

    Rock avalanches, debris flows, and related phenomena consist of grain-fluid mixtures that move across three-dimensional terrain. In all these phenomena the same basic forces, govern motion, but differing mixture compositions, initial conditions, and boundary conditions yield varied dynamics and deposits. To predict motion of diverse grain-fluid masses from initiation to deposition, we develop a depth-averaged, threedimensional mathematical model that accounts explicitly for solid- and fluid-phase forces and interactions. Model input consists of initial conditions, path topography, basal and internal friction angles of solid grains, viscosity of pore fluid, mixture density, and a mixture diffusivity that controls pore pressure dissipation. Because these properties are constrained by independent measurements, the model requires little or no calibration and yields readily testable predictions. In the limit of vanishing Coulomb friction due to persistent high fluid pressure the model equations describe motion of viscous floods, and in the limit of vanishing fluid stress they describe one-phase granular avalanches. Analysis of intermediate phenomena such as debris flows and pyroclastic flows requires use of the full mixture equations, which can simulate interaction of high-friction surge fronts with more-fluid debris that follows. Special numerical methods (described in the companion paper) are necessary to solve the full equations, but exact analytical solutions of simplified equations provide critical insight. An analytical solution for translational motion of a Coulomb mixture accelerating from rest and descending a uniform slope demonstrates that steady flow can occur only asymptotically. A solution for the asymptotic limit of steady flow in a rectangular channel explains why shear may be concentrated in narrow marginal bands that border a plug of translating debris. Solutions for static equilibrium of source areas describe conditions of incipient slope instability, and other static solutions show that nonuniform distributions of pore fluid pressure produce bluntly tapered vertical profiles at the margins of deposits. Simplified equations and solutions may apply in additional situations identified by a scaling analysis. Assessment of dimensionless scaling parameters also reveals that miniature laboratory experiments poorly simulate the dynamics of full-scale flows in which fluid effects are significant. Therefore large geophysical flows can exhibit dynamics not evident at laboratory scales.

  6. Variability in the Heritability of Body Mass Index: A Systematic Review and Meta-Regression

    PubMed Central

    Elks, Cathy E.; den Hoed, Marcel; Zhao, Jing Hua; Sharp, Stephen J.; Wareham, Nicholas J.; Loos, Ruth J. F.; Ong, Ken K.

    2012-01-01

    Evidence for a major role of genetic factors in the determination of body mass index (BMI) comes from studies of related individuals. Despite consistent evidence for a heritable component of BMI, estimates of BMI heritability vary widely between studies and the reasons for this remain unclear. While some variation is natural due to differences between populations and settings, study design factors may also explain some of the heterogeneity. We performed a systematic review that identified 88 independent estimates of BMI heritability from twin studies (total 140,525 twins) and 27 estimates from family studies (42,968 family members). BMI heritability estimates from twin studies ranged from 0.47 to 0.90 (5th/50th/95th centiles: 0.58/0.75/0.87) and were generally higher than those from family studies (range: 0.24–0.81; 5th/50th/95th centiles: 0.25/0.46/0.68). Meta-regression of the results from twin studies showed that BMI heritability estimates were 0.07 (P?=?0.001) higher in children than in adults; estimates increased with mean age among childhood studies (+0.012/year, P?=?0.002), but decreased with mean age in adult studies (?0.002/year, P?=?0.002). Heritability estimates derived from AE twin models (which assume no contribution of shared environment) were 0.12 higher than those from ACE models (P?

  7. Breaking Gaussian incompatibility on continuous variable quantum systems

    E-print Network

    Teiko Heinosaari; Jukka Kiukas; Jussi Schultz

    2015-05-11

    We characterise Gaussian quantum channels that are Gaussian incompatibility breaking, that is, transform every set of Gaussian measurements into a set obtainable from a joint Gaussian observable via Gaussian postprocessing. Such channels represent local noise which renders measurements useless for Gaussian EPR-steering, providing the appropriate generalisation of entanglement breaking channels for this scenario. Understanding the structure of Gaussian incompatibility breaking channels contributes to the resource theory of noisy continuous variable quantum information protocols.

  8. Phytoplankton scales of variability in the California Current System: 1. Interannual and cross-shelf variability

    E-print Network

    Thomas, Andrew

    . Introduction [2] The California Current System (CCS) is an eastern boundary flow that originates southward flow produce meanders and eddies around the core of the coastal jet [e.g., Marchesiello et al., 1998; Soto-Mardones et al., 2004; Barth et al., 2005]. Moored current meters reveal the dominance

  9. Variability of pigment biomass in the California Current system as determined by satellite imagery. I - Spatial variability

    NASA Technical Reports Server (NTRS)

    Smith, Raymond C.; Zhang, Xueyun; Michaelsen, Joel

    1988-01-01

    Spatial variability of chlorophyll in the California Current system was analyzed using Coastal Zone Color Scanner (CZCS) imagery. A total of 48 images were analyzed to produce seasonal averages and variances, gradients, and power spectra. Roughly one third to one half of the variance in pigment biomass can be explained by consistent, large-scale gradients. In general, biomass is higher in the north and in nearshore areas. Nearshore areas also have proportionally more small-scale variability than the areas offshore. Slopes of the power spectra for nearshore areas are about -2.2 (for spatial scales of 10-100 km), while slopes for offshore areas are about -3. In addition, the power spectra show evidence of a change in slope at about 10 km, with slopes of about -1 for shorter-length scales. This may indicate that biological processes dominate the smaller scales, while mesoscale eddies and geostrophic currents dominate the larger scales.

  10. Tenth Goddard Conference on Mass Storage Systems and Technologies in Cooperation with the Nineteenth IEEE Symposium on Mass Storage Systems

    NASA Technical Reports Server (NTRS)

    Kobler, Benjamin (Editor); Hariharan, P. C. (Editor)

    2002-01-01

    This document contains copies of those technical papers received in time for publication prior to the Tenth Goddard Conference on Mass Storage Systems and Technologies which is being held in cooperation with the Nineteenth IEEE Symposium on Mass Storage Systems at the University of Maryland University College Inn and Conference Center April 15-18, 2002. As one of an ongoing series, this Conference continues to provide a forum for discussion of issues relevant to the ingest, storage, and management of large volumes of data. The Conference encourages all interested organizations to discuss long-term mass storage requirements and experiences in fielding solutions. Emphasis is on current and future practical solutions addressing issues in data management, storage systems and media, data acquisition, long-term retention of data, and data distribution. This year's discussion topics include architecture, future of current technology, storage networking with emphasis on IP storage, performance, standards, site reports, and vendor solutions. Tutorials will be available on perpendicular magnetic recording, object based storage, storage virtualization and IP storage.

  11. An extrasolar planetary system with three Neptune-mass planets

    E-print Network

    C. Lovis; M. Mayor; F. Pepe; Y. Alibert; W. Benz; F. Bouchy; A. C. M. Correia; J. Laskar; C. Mordasini; D. Queloz; N. C. Santos; S. Udry; J. -L. Bertaux; J. -P. Sivan

    2007-03-01

    Over the past two years, the search for low-mass extrasolar planets has led to the detection of seven so-called 'hot Neptunes' or 'super-Earths' around Sun-like stars. These planets have masses 5-20 times larger than the Earth and are mainly found on close-in orbits with periods of 2-15 days. Here we report a system of three Neptune-mass planets with periods of 8.67, 31.6 and 197 days, orbiting the nearby star HD 69830. This star was already known to show an infrared excess possibly caused by an asteroid belt within 1 AU (the Sun-Earth distance). Simulations show that the system is in a dynamically stable configuration. Theoretical calculations favour a mainly rocky composition for both inner planets, while the outer planet probably has a significant gaseous envelope surrounding its rocky/icy core; the outer planet orbits within the habitable zone of this star.

  12. Mass spectrometric identification, sequence evolution, and intraspecific variability of dimeric peptides encoded by cockroach akh genes.

    PubMed

    Sturm, Sebastian; Predel, Reinhard

    2015-02-01

    Neuropeptides are structurally the most diverse group of messenger molecules of the nervous system. Regarding neuropeptide identification, distribution, function, and evolution, insects are among the best studied invertebrates. Indeed, more than 100 neuropeptides are known from single species. Most of these peptides can easily be identified by direct tissue or cell profiling using MALDI-TOF MS. In these experiments, protein hormones with extensive post-translational modifications such as inter- and intramolecular disulfides are usually missed. It is evident that an exclusion of these bioactive molecules hinders the utilization of direct profiling methods in comprehensive peptidomic analyses. In the current study, we focus on the detection and structural elucidation of homo- and heterodimeric adipokinetic hormone precursor-related peptides (APRPs) of cockroaches. The physiological relevance of these molecules with highly conserved sequences in insects is still uncertain. Sequence similarities with vertebrate growth hormone-releasing factors have been reported, but remarkably, few data regarding APRP processing exist and these data are restricted to locusts. Here, we elucidated sequences of carbamidomethylated APRP monomers of different cockroaches by means of MALDI-TOF MS(2), and we were able to identify a surprisingly large number of APRP sequences, resulting either from intraspecific amino acid substitutions within the APRP sequences or C-terminal truncated APRPs. PMID:25524231

  13. Temporal and sex-specific variability in Rhinoceros Auklet diet in the central California Current system

    NASA Astrophysics Data System (ADS)

    Carle, Ryan D.; Beck, Jessie N.; Calleri, David M.; Hester, Michelle M.

    2015-06-01

    We used stable isotopes (?15N and ?13C) and compared prey provided to chicks by each sex to evaluate seasonal and sex-specific diets in Rhinoceros Auklets (Cerorhinca monocerata) in the central California Current system during 2012-2013. Mixing models indicated northern anchovy (Engraulis mordax) were important prey for adults during fall/winter and juvenile rockfishes (Sebastes spp.) were important prey during incubation both years. Adult trophic level increased between incubation and chick-rearing periods in both years. During 2012, ?15N and ?13C of chick-rearing males and females differed significantly; mixing models indicated that females ate more Pacific saury (Cololabis saira) and less market squid (Doryteuthis opalescens) than males. Likewise, females delivered significantly more Pacific saury and less market squid to chicks than males during 2012. Chick growth (g d- 1) and chick survival to fledging were significantly lower during 2012 than 2013, likely because chicks were fed lesser quality prey or fed less frequently in 2012. Lesser body mass of females during incubation in 2012 indicated sex-specific diet differences may have been related to female energetic constraints. The observed variability in Rhinoceros Auklet diet underscores the importance of managing multiple prey populations in this system so that generalist predators have sufficient resources through changing conditions.

  14. Analyses of Variable Refrigerant Flow and Exergy in Air Conditioning Systems

    Microsoft Academic Search

    Rashid Ali Alshatti

    2011-01-01

    This thesis consists of two research problems in the air conditioning (A\\/C) area. For the first problem, the aim is to model and simulate a variable refrigerant flow (VRF) air conditioning system. The coefficient of performance (COP) for refrigeration or heat pump system is one of the critical parameters for designing an air conditioning system. The modeling of the system

  15. Fault Tolerant Control for Takagi-Sugeno systems with unmeasurable premise variables by trajectory tracking

    E-print Network

    Paris-Sud XI, Université de

    Fault Tolerant Control for Takagi-Sugeno systems with unmeasurable premise variables by trajectory for fault tolerant control of nonlinear systems described by Takagi- Sugeno fuzzy systems with unmeasurable the knowledge of the system states and of the occurring faults. These signals are estimated from a Proportional

  16. Fuzzy logic based intelligent control of a variable speed cage machine wind generation system

    Microsoft Academic Search

    M. G. Simoes; B. K. Bose; R. J. Spiegel

    1997-01-01

    The paper describes a variable speed wind generation system where fuzzy logic principles are used for efficiency optimization and performance enhancement control. A squirrel cage induction generator feeds the power to a double-sided pulse width modulated converter system which pumps power to a utility grid or can supply to an autonomous system. The generation system has fuzzy logic control with

  17. A method of variable spacing for controlled plant growth systems in spaceflight and terrestrial agriculture applications

    NASA Technical Reports Server (NTRS)

    Knox, J.

    1986-01-01

    A higher plant growth system for Controlled Ecological Life Support System (CELSS) applications is described. The system permits independent movement of individual plants during growth. Enclosed within variable geometry growth chambers, the system allocates only the volume required by the growing plants. This variable spacing system maintains isolation between root and shoot environments, providing individual control for optimal growth. The advantages of the system for hydroponic and aeroponic growth chambers are discussed. Two applications are presented: (1) the growth of soybeans in a space station common module, and (2) in a terrestrial city greenhouse.

  18. A low dead time variable CMOS delay for the Nuclear Weapons Identification System

    Microsoft Academic Search

    B. S. Puckett; M. J. Paulus; J. T. Mihalczo; T. V. Blalock

    1998-01-01

    The architecture and performance of a new CMOS, low dead time, variable delay is described. This delay was developed to provide channel synchronization in the front-end electronics ASIC of the Nuclear Weapons Identification System (NWIS). The delay is variable over a 500 ns range in steps of less than 100 ps. Low dead time is achieved by using a switched

  19. Overview of the Use of Natural Variability Concepts in Managing Ecological Systems

    Microsoft Academic Search

    Peter B. Landres; Penelope Morgan; Frederick J. Swanson

    1999-01-01

    Natural resource managers have used natural variability concepts since the early 1960s and are increasingly relying on these concepts to maintain biological diversity, to restore ecosystems that have been severely altered, and as benchmarks for assessing anthropogenic change. Management use of natural variability relies on two concepts: that past conditions and processes provide context and guidance for managing ecological systems

  20. Tackling High Variability in Video Surveillance Systems through a Model Transformation Approach

    E-print Network

    Paris-Sud XI, Université de

    Tackling High Variability in Video Surveillance Systems through a Model Transformation Approach multiple variability factors. Video surveillance is a good candidate for which we have an extensive experi a possible synergy between the video surveillance software domain and model-driven engineer- ing (MDE

  1. Language as a complex system: the case of phonetic variability Philippe Blache & Christine Meunier

    E-print Network

    Paris-Sud XI, Université de

    Language as a complex system: the case of phonetic variability Philippe Blache & Christine Meunier. In this perspective, each linguistic domain, such as phonetics, phonology, syntax, pragmatics, etc., is described a unique domain. We illustrate this problem with the case of phonetic variability and show how different

  2. Control valve system for a continuously variable belt driven transmission for motor vehicles

    Microsoft Academic Search

    U. Eggert; H. Staffel

    1988-01-01

    This patient describes a hydraulic valve system for controlling a continuously variable drive ratio automotive vehicle transmission adapted to shift continuously between different drive ratios and having first and second control pulleys driveably connected by an endless traction belt, a displacement cylinder associated with each pulley, the location of the belt on each pulley being radially variable in response to

  3. Data dependent systems methodology for lumped mass modeling of structures

    NASA Technical Reports Server (NTRS)

    Pandit, Sudhakar M.

    1988-01-01

    Limitations of the frequency domain methods in analyzing structura1 vibrations has created an awareness of the comparative merits of the time domain methods. Although time domain methods would be ideal for modeling large precisions space systems, the popular methods based on fitting theoretical response to actual data by least squares are too sensitive to noise and require too much data to be suitable for orbiting space crafts. This paper briefly reviews the theory and illustrative applications of a time domain methodology called Data Dependent Systems (DDS) that eliminates these limitations. Simulation results are presented to demonstrate a better than 4-place accuracy in the identifications of all system parameters, both modal (frequencies, damping ratios, and mode shapes) and physical (mass, stiffness, and damping matrices).

  4. Variability of pigment biomass in the California Current system as determined by satellite imagery. II - Temporal variability

    NASA Technical Reports Server (NTRS)

    Michaelsen, Joel; Zhang, Xueyun; Smith, Raymond C.

    1988-01-01

    Characteristics of temporal variability in the California Current system are analyzed using a 30-month time series of CZCS imagery. About 20-25 percent of the variance is produced by a periodic annual cycle with peak values in winter. Analysis of ship-based chlorophyll measurements indicates that the winter peak is only characteristic of the upper portion of the euphotic zone and that total water column chlorophyll peaks during the spring upwelling season. Satellite studies of intraannual variability are modulated by strong 5- to 6-day oscillation in the availability of usable imagery, resulting from a combination of satellite orbital dynamics, which produces images of the study area roughly 4 out of every 6 days, and an oscillation in cloud cover, which controls the availability of clear imagery. The cloud cover oscillation, which is also present in coastal winds, undoubtedly affects the ocean surface and biases the data obtained by satellites. Analysis of data using a 5-day time step indicates that the predominant mode of nonseasonal variability is characterized by in-phase fluctuations throughout the southern and central California coastal region.

  5. A high pressure modulated molecular beam mass spectrometric sampling system

    NASA Technical Reports Server (NTRS)

    Stearns, C. A.; Kohl, F. J.; Fryburg, G. C.; Miller, R. A.

    1977-01-01

    The current state of understanding of free-jet high pressure sampling is critically reviewed and modifications of certain theoretical and empirical considerations are presented. A high pressure, free-jet expansion, modulated molecular beam, mass spectrometric sampling apparatus was constructed and this apparatus is described in detail. Experimental studies have demonstrated that the apparatus can be used to sample high temperature systems at pressures up to one atmosphere. Condensible high temperature gaseous species have been routinely sampled and the mass spectrometric detector has provided direct identification of sampled species. System sensitivity is better than one tenth of a part per million. Experimental results obtained with argon and nitrogen beams are presented and compared to theoretical predictions. These results and the respective comparison are taken to indicate acceptable performance of the sampling apparatus. Results are also given for two groups of experiments related to hot corrosion studies. The formation of gaseous sodium sulfate in doped methane-oxygen flames was characterized and the oxidative vaporization of metals was studied in an atmospheric pressure flowing gas system to which gaseous salt partial pressures were added.

  6. Control System Upgrade for a Mass Property Measurement Facility

    NASA Technical Reports Server (NTRS)

    Chambers, William; Hinkle, R. Kenneth (Technical Monitor)

    2002-01-01

    The Mass Property Measurement Facility (MPMF) at the Goddard Space Flight Center has undergone modifications to ensure the safety of Flight Payloads and the measurement facility. The MPMF has been technically updated to improve reliability and increase the accuracy of the measurements. Modifications include the replacement of outdated electronics with a computer based software control system, the addition of a secondary gas supply in case of a catastrophic failure to the gas supply and a motor controlled emergency stopping feature instead of a hard stop.

  7. Stochastic variability in stress, sleep duration and sleep quality across the distribution of body mass index: Insights from quantile regression

    PubMed Central

    Matthews, Stephen A.; Chen, Vivian Y.J.

    2013-01-01

    Purpose This study investigates whether sleep and stress are associated with body mass index (BMI) respectively, explores whether the combination of stress and sleep is also related to BMI, and demonstrates a thorough picture of how these associations above vary across the distribution of BMI values. Methods We analyze the data from 3,318 men and 6,689 women in the Philadelphia area using quantile regression (QR) to evaluate the relationships between sleep, stress, and obesity by gender. Results Our substantive findings include: (1) high and/or extreme stress were related to roughly an increase of 1.2 in BMI even after accounting for other covariates; (2) the pathways linking sleep and BMI differed by gender; with BMI for men increasing by 0.77–1 units with reduced sleep duration, and BMI for women declining by 0.12 unit with one units increase in sleep quality; (3) stress and sleep-related variables were confounded but there was little evidence for moderation between these two; (4) the QR results demonstrate that the association between high and/or extreme stress to BMI varied stochastically across the distribution of BMI values, with an upward trend, suggesting that stress played a more important role among adults with higher BMI (i.e., BMI > 26 for both genders); and (5) the QR plots of sleep-related variables show similar patterns, with stronger effects on BMI at the upper end of BMI distribution. Conclusions Our findings indicated that having sufficient and quality sleep and reducing stress may be two intervention strategies that can be promoted among adults in Philadelphia. PMID:23385490

  8. A new method for observing the running states of a single-variable nonlinear system.

    PubMed

    Meng, Yu; Chen, Hong; Chen, Cheng

    2015-03-01

    In order to timely grasp a single variable nonlinear system running states, a new method called Scatter Point method is put forward in this paper. It can be used to observe or monitor the running states of a single variable nonlinear system in real-time. In this paper, the definition of the method is given at first, and then its working principle is expounded theoretically, after this, some physical experiments based on Chua's nonlinear system are conducted. At the same time, many scatter point graphs are measured by a general analog oscilloscope. The motion, number, and distribution of these scatter points shown on the oscilloscope screen can directly reflect the current states of the tested system. The experimental results further confirm that the method is effective and practical, in which the system running states are not easily lost. In addition, this method is not only suitable for single variable systems but also for multivariable systems. PMID:25833428

  9. Structure of variability of Alboran Sea frontal system

    SciTech Connect

    Cheney, R.E.; Doblar, R.A.

    1982-01-20

    Physical characteristics of the Alboran Sea in the western Mediterranean were examined in October 1977 during a survey by ship and aircraft. The main features observed were a distinct oceanic front coinciding with the jet of incoming North Atlantic water and an associated anticyclonic gyre in the western half of the basin. The front was confined to the upper 200 m and was a continuous feature extending from the Strait of Gibraltar 500 km eastward to the prime meridian. Of particular interest was the observed variability of the anticyclonic gyre. In 10 days between two surveys the center of the gyre shifted 50 km westward. This shift may correspond to changes in strength of the North Atlantic inflow as inferred by local wind and the average atmospheric pressure over the western Mediterranean.

  10. Energy-Saving Design for Pressure Difference Control in Variable Flow Air Conditioning Systems

    E-print Network

    Chen, Y.; Zhang, Z.

    2006-01-01

    This paper analyzes energy-saving design for pressure-difference control in a variable flow air conditioning system, including the application of a pressure-difference control valve and the installation position of a pressure-difference transducer...

  11. Improving Control of a Dual-Duct Single-Fan Variable Air Volume Systems 

    E-print Network

    Wei, G.; Martinez, J.; Minihan, T.; Brundidge, T.; Claridge, D. E.; Turner, W. D.

    2003-01-01

    This paper discusses improved control strategies for dual-duct single-fan variable air volume (VAV) systems. Common control strategy for supply air volume modulation is evaluated, and an improved air volume control strategy that maintains separate...

  12. A Simple and Quick Chilled Water Loop Balancing for Variable Flow System

    E-print Network

    Zhu, Y.; Batten, T.; Turner, W. D.; Claridge, D. E.; Liu, M.

    2000-01-01

    For many modem buildings, the chilled water loops and risers are equipped with variable speed pumping systems. How to quickly balance the loop or riser to satisfy the cooling requirement and reduce energy consumption is a very interesting topic...

  13. Generalized treatment of optically-induced forces and potentials in optomechanically variable photonic systems.

    SciTech Connect

    Rakich, Peter T.; Wang, Zheng (Massachusetts Institute of Technology, Cambridge, MA); Popovic, Milos A. (Massachusetts Institute of Technology, Cambridge, MA)

    2009-01-01

    The authors establish a fundamental relationship between the phase and amplitude responses of an optomechanically variable photonic circuit and the forces and potentials produced by light. These results are illustrated through resonant and nonresonant multi-port systems.

  14. Efficient Stochastic Simulation of Biological Systems with Multiple Variable Volumes

    Microsoft Academic Search

    Cristian Versari; Nadia Busi

    2008-01-01

    The application of concurrent calculi to the formalisation of biological systems constitutes a promis- ing approach to the analysis in silico of biological phenomena. The Gillespie algorithm is one of the main models exploited for their stochastic simulation. While the original algorithm considers only one fixed-volume compartment, the simulation of biological systems often requires multi-compartment semantics. In this paper we

  15. Long-Term Quadrature Light Variability in Early Type Interacting Binary Systems

    NASA Astrophysics Data System (ADS)

    Peters, Geraldine J.; Wilson, R. E.; Vaccaro, T. R.

    2014-01-01

    Four years of Kepler observations have revealed a phenomenon in the light curves of short-period Algol-type eclipsing binaries that has never been reported from ground-based photometry. These systems display unequal brightness at their quadrature phases that numerically reverses over a time scale of about 100-400 days. We call these systems L/T (leading hemisphere/ trailing hemisphere) variables. Twenty-one such systems have so far been identified in the Kepler database and at least three classes of L/T behavior have been identified. The prototype is WX Draconis (A8V + K0IV, P=1.80 d) which shows L/ T light variations of 2-3%. The primary is a delta Scuti star with a dominant pulsation period of 41 m. The Kepler light curves are being analyzed with the 2013 version of the Wilson-Devinney (WD) program that includes major improvements in modeling star spots (i.e. spot motions due to drift and stellar rotation and spot growth and decay). Preliminary analysis of the WX Dra data suggests that the L/T variability can be fit with either an accretion hot spot on the primary (T = 2.3 T_phot) that jumps in longitude or a magnetic cool spotted region on the secondary. If the latter model is correct the dark region must occupy at least 20% of the surface of the facing hemisphere of the secondary if it is completely black, or a larger area if not completely black. In both hot and cool spot scenarios magnetic fields must play a role in the activity. Echelle spectra were recently secured with the KPNO 4-m telescope to determine the mass ratios of the L/T systems and their spectral types. This information will allow us to assess whether the hot or cool spot model explains the L/T activity. Progress toward this goal will be presented. Support from NASA grants NNX11AC78G and NNX12AE44G and USC’s Women in Science and Engineering (WiSE) program is greatly appreciated.

  16. Experience with the UniTree mass storage system

    SciTech Connect

    Holmes, H.H.; Loken, S.

    1992-09-01

    Lawrence Berkeley Laboratory (LBL) is a beta test site for the UniTree mass storage system. Our initial configuration is based on a Sun workstation and includes 10 gigabytes (GB) of magnetic disk cache, 700 GB of Exabyte 8 mm tape storage, with two tape robots. We support a user community of 15 to 20 active users, about 250,000 files, and 33 GB of user data. The largest file stored is 1.5 GB. As of May 1992, we consider the system to be adequately stable and reliable for production use. As a beta site, we have worked on the Sun port, on the tape drivers for SunOS, and on integrating our tape robots into the UniTree software. File retrieval from tape usually takes less than five minutes. Continuing concerns are tape longevity and reliability, and improving performance to support 100 Mb FDDI.

  17. Systems for 42 V mass-market automobiles

    NASA Astrophysics Data System (ADS)

    Keim, Thomas A.

    With the introduction of the Toyota Crown Royal Saloon in August, 2001, 42 V automotive electrical systems made the transition from a technology for the future to present-day production. Nevertheless, there is widespread malaise in the 42 V technical community, stemming from a slower than expected introduction to the marketplace. This paper discusses some of the reasons for the slow adoption of this technology, and indicates a possible way forward. This paper looks beyond the initial uses of 42 V in limited-volume, high-end cars and light trucks, and discusses the prospects for 42 V in mass-market vehicles, given what is presently known about the technology. It is concluded that a case can be made for 42 V, even at some increment in cost. The motivation is improved fuel economy. The cost targets necessary for this benefit to be achieved are discussed, and new components being widely discussed as part of future electrical systems are evaluated for mass-market applications. New developments with higher potential are suggested.

  18. Variability of African Farming Systems from Phenological Analysis of NDVI Time Series

    NASA Technical Reports Server (NTRS)

    Vrieling, Anton; deBeurs, K. M.; Brown, Molly E.

    2011-01-01

    Food security exists when people have access to sufficient, safe and nutritious food at all times to meet their dietary needs. The natural resource base is one of the many factors affecting food security. Its variability and decline creates problems for local food production. In this study we characterize for sub-Saharan Africa vegetation phenology and assess variability and trends of phenological indicators based on NDVI time series from 1982 to 2006. We focus on cumulated NDVI over the season (cumNDVI) which is a proxy for net primary productivity. Results are aggregated at the level of major farming systems, while determining also spatial variability within farming systems. High temporal variability of cumNDVI occurs in semiarid and subhumid regions. The results show a large area of positive cumNDVI trends between Senegal and South Sudan. These correspond to positive CRU rainfall trends found and relate to recovery after the 1980's droughts. We find significant negative cumNDVI trends near the south-coast of West Africa (Guinea coast) and in Tanzania. For each farming system, causes of change and variability are discussed based on available literature (Appendix A). Although food security comprises more than the local natural resource base, our results can perform an input for food security analysis by identifying zones of high variability or downward trends. Farming systems are found to be a useful level of analysis. Diversity and trends found within farming system boundaries underline that farming systems are dynamic.

  19. Variable Structure Model Reference Adaptive Control, for Vehicle Automatic Steering System

    Microsoft Academic Search

    Ardeshir Karami Mohammadi; Mohammadreza Saee

    2009-01-01

    A variable structure model reference adaptive control (VS-MRAC) strategy for automatic active steering of a two wheel steering car is proposed. An ideal steering system with fixed properties and moving on an ideal road is used as the reference model, and the automatic active steering system is forced to attain the same behavior as the reference model. The proposed system

  20. Nonlinear state space modeling of a variable speed wind power generation system

    Microsoft Academic Search

    S. H. Edjtahed; M. Karrari; W. Rosehart; O. P. Malik

    2006-01-01

    New problems emerging from the increased production of power from renewable resources are becoming a good challenge. To face the new challenges, accurate modeling of such systems is required. For example, to be able to apply advanced control strategies, usually a linearized state space representation of the system is needed. Taking a variable speed cage machine wind generation system as

  1. Energy efficient PCM-based variable air volume air conditioning system for modern buildings

    Microsoft Academic Search

    R. Parameshwaran; S. Harikrishnan; S. Kalaiselvam

    2010-01-01

    This work aims at achieving enhanced energy conservation for space conditioning with the application of a new combined variable air volume (VAV)-based chilled water air conditioning (A\\/C) system and thermal energy storage (TES) system. The phase change material (PCM) used in this system exhibited good charging and discharging characteristics that directly helped in conserving the overall energy spent on cooling

  2. Energy efficient control of variable speed pumps in complex building central air-conditioning systems

    Microsoft Academic Search

    Zhenjun Ma; Shengwei Wang

    2009-01-01

    This paper presents the optimal control strategies for variable speed pumps with different configurations in complex building air-conditioning systems to enhance their energy efficiencies. Through a detailed analysis of the system characteristics, the pressure drop models for different water networks in complex air-conditioning systems are developed and then used to formulate an optimal pump sequence control strategy. This sequence control

  3. Application of two-stage fuzzy PID control in variable refrigerant volume air conditioning systems

    Microsoft Academic Search

    Xu Jinqiang; Feng Zi-ping

    2009-01-01

    The variable refrigerant volume (VRV) air conditioning systems have been employed in small and medium sized buildings recently for its advantages of comfort, energy conservation and easy maintenance. However, the optimal control of VRV air conditioning systems is very difficult due to cross-coupling system parameters and time-variant operating conditions. In this paper, the indoor temperatures are taken as the controlled

  4. Design and implementation of a variable frequency regulatory system for water supply

    Microsoft Academic Search

    D. T. W. Chan; Wujiu Li

    1996-01-01

    The designs of the variable frequency constant pressure water supply for a single hydraulic pump and high power multiple hydraulic motors systems are presented in this paper. This system can save energy by controlling the speed of the pipe motors which depend upon the number of consumers in use. This system was also successfully implemented in most of the modern

  5. Variable-delay feedback control of unstable steady states in retarded time-delayed systems

    E-print Network

    Aleksandar Gjurchinovski; Viktor Urumov

    2010-07-06

    We study the stability of unstable steady states in scalar retarded time-delayed systems subjected to a variable-delay feedback control. The important aspect of such a control problem is that time-delayed systems are already infinite-dimensional before the delayed feedback control is turned on. When the frequency of the modulation is large compared to the system's dynamics, the analytic approach consists of relating the stability properties of the resulting variable-delay system with those of an analogous distributed delay system. Otherwise, the stability domains are obtained by a numerical integration of the linearized variable-delay system. The analysis shows that the control domains are significantly larger than those in the usual time-delayed feedback control, and that the complexity of the domain structure depends on the form and the frequency of the delay modulation.

  6. The systemic velocities of four long-period cataclysmic variable stars

    NASA Astrophysics Data System (ADS)

    North, R. C.; Marsh, T. R.; Kolb, U.; Dhillon, V. S.; Moran, C. K. J.

    2002-12-01

    Although a large number of orbital periods of cataclysmic variable (CV) stars have been measured, comparison of period and luminosity distributions with evolutionary theory is affected by strong selection effects. A test has been discovered that is independent of these selection effects and is based upon the kinematics of CVs. If the standard models of evolution are correct then long-period (Porb > 5 h) CVs should be typically less than 1.5 Gyr old, and their line-of-sight velocity dispersion (??) should be small. We present results from a pilot study, which indicate that this postulate is indeed true. Four long-period dwarf novae (EM Cyg, V426 Oph, SS Cyg and AH Her) were observed over a complete orbit, in order for accurate radial velocities to be obtained. We find values of -1.7, 5.4, 15.4 and 1.8 km s-1 with uncertainties of the order of 3 km s-1, referred to the dynamical local standard of rest, leading to a dispersion of ~8 km s-1. Calculation of a 95 per cent confidence interval gives the result 4 < ?? < 28 km s-1 compared with a prediction of 15 km s-1. We also have an improved determination of mass donor spectral type, K2 and q for the four systems.

  7. Evidence for lower variability of coronary artery calcium mineral mass measurements by multi-detector computed tomography in a community-based cohort—Consequences for progression studies

    Microsoft Academic Search

    Udo Hoffmann; Uwe Siebert; Arabella Bull-Stewart; Stephan Achenbach; Maros Ferencik; Fabian Moselewski; Thomas J. Brady; Joseph M. Massaro; Christopher J. O’Donnell

    2006-01-01

    PurposeTo compare the measurement variability for coronary artery calcium (CAC) measurements using mineral mass compared with a modified Agatston score (AS) or volume score (VS) with multi-detector CT (MDCT) scanning, and to estimate the potential impact of these methods on the design of CAC progression studies.

  8. Design of variable frequency endoscope ultrasonic digital imaging system

    NASA Astrophysics Data System (ADS)

    Li, Ya-nan; Bai, Bao-ping; Chen, Xiao-dong; Zhao, Qiang; Deng, Hao-ran; Wang, Yi; Yu, Dao-yin

    2013-12-01

    This paper presented a real-time endoscope ultrasonic digital imaging system, which was based on FPGA and applied for gastrointestinal examination. Four modules, scan-line data processing module, coordinate transformation and interpolation algorithm module, cache reading and writing control module and transmitting and receiving control module were included in this FPGA based system. Through adopting different frequency ultrasound probes in a single insertion of endoscope, the system showed a high speed data processing mechanism capable of achieving images with various display effects. A high-precision modified coordinate calibration CORDIC (HMCC-CORDIC) algorithm was employed to realize coordinate transformation and interpolation simultaneously, while the precision and reliability of the algorithm could be greatly improved through utilizing the pipeline structure based on temporal logic. Also, system real-time control by computer could be achieved through operating under the condition of USB2.0 interface. The corresponding experimental validations proved the feasibility and the correctness of the proper data processing mechanism, the HMCC-CORDIC algorithm and the USB real-time control. Finally, the specific experimental sample, a tissue mimicking phantom, was imaged in real-time (25 frames per second) by an endoscope ultrasonic imaging system with image size 1024×1024. The requirements for clinical examination could be well satisfied with the imaging parameters discussed above.

  9. A computational method to extract macroscopic variables and their dynamics in multiscale systems

    E-print Network

    Gary Froyland; Georg A. Gottwald; Andy Hammerlindl

    2014-09-29

    This paper introduces coordinate-independent methods for analysing multiscale dynamical systems using numerical techniques based on the transfer operator and its adjoint. In particular, we present a method for testing whether an arbitrary dynamical system exhibits multiscale behaviour and for estimating the time-scale separation. For systems with such behaviour, we establish techniques for analysing the fast dynamics in isolation, extracting slow variables for the system, and accurately simulating these slow variables at a large time step. We illustrate our method with numerical examples and show how the reduced slow dynamics faithfully represents statistical features of the full dynamics which are not coordinate dependent.

  10. Large-scale variability of wind erosion mass flux rates at Owens Lake 1. Vertical profiles of horizontal mass fluxes of wind-eroded particles with diameter greater than 50 ?m

    USGS Publications Warehouse

    Gillette, Dale A.; Fryrear, D.W.; Xiao, Jing Bing; Stockton, Paul; Ono, Duane; Helm, Paula J.; Gill, Thomas E; Ley, Trevor

    1997-01-01

    A field experiment at Owens (dry) Lake, California, tested whether and how the relative profiles of airborne horizontal mass fluxes for >50-?m wind-eroded particles changed with friction velocity. The horizontal mass flux at almost all measured heights increased proportionally to the cube of friction velocity above an apparent threshold friction velocity for all sediment tested and increased with height except at one coarse-sand site where the relative horizontal mass flux profile did not change with friction velocity. Size distributions for long-time-averaged horizontal mass flux samples showed a saltation layer from the surface to a height between 30 and 50 cm, above which suspended particles dominate. Measurements from a large dust source area on a line parallel to the wind showed that even though the saltation flux reached equilibrium ?650 m downwind of the starting point of erosion, weakly suspended particles were still input into the atmosphere 1567 m downwind of the starting point; thus the saltating fraction of the total mass flux decreased after 650 m. The scale length difference and ratio of 70/30 suspended mass flux to saltation mass flux at the farthest down wind sampling site confirm that suspended particles are very important for mass budgets in large source areas and that saltation mass flux can be a variable fraction of total horizontal mass flux for soils with a substantial fraction of <100-?m particles.

  11. Volcanic Gas Emissions Mapping Using a Mass Spectrometer System

    NASA Technical Reports Server (NTRS)

    Griffin, Timothy P.; Diaz, J. Andres

    2008-01-01

    The visualization of hazardous gaseous emissions at volcanoes using in-situ mass spectrometry (MS) is a key step towards a better comprehension of the geophysical phenomena surrounding eruptive activity. In-Situ gas data consisting of helium, carbon dioxide, sulfur dioxide, and other gas species, were acquired with an MS system. MS and global position system (GPS) data were plotted on ground imagery, topography, and remote sensing data collected by a host of instruments during the second Costa Rica Airborne Research and Technology Applications (CARTA) mission This combination of gas and imaging data allowed 3-dimensional (3-D) visualization of the volcanic plume end the mapping of gas concentration at several volcanic structures and urban areas This combined set of data has demonstrated a better tool to assess hazardous conditions by visualizing and modeling of possible scenarios of volcanic activity. The MS system is used for in-situ measurement of three-dimensional gas concentrations at different volcanic locations with three different transportation platforms, aircraft, auto, and hand carried. The demonstration for urban contamination mapping is also presented as another possible use for the MS system.

  12. Time Evolution of the Dynamical Variables of a Stochastic System.

    ERIC Educational Resources Information Center

    de la Pena, L.

    1980-01-01

    By using the method of moments, it is shown that several important and apparently unrelated theorems describing average properties of stochastic systems are in fact particular cases of a general law; this method is applied to generalize the virial theorem and the fluctuation-dissipation theorem to the time-dependent case. (Author/SK)

  13. Optimal limited state variable feedback controllers for linear systems

    Microsoft Academic Search

    W. Levine; T. Johnson; M. Athans

    1971-01-01

    This paper considers the problem of designing compensators, the dimensions of which are fixed a priori, for linear systems. Two types of compensators are considered: first, static (gain only) compensators which operate directly upon the output signals to generate the controls, and second, dynamic compensators of fixed dimension. The equations that define the parameters of such compensators are developed.

  14. Design of Adaptive Variable Structure Control System for Aerospace Vehicle

    Microsoft Academic Search

    Tong Chunxia

    2006-01-01

    The aerospace vehicle is a hypersonic vehicle for long distance transport in near-space. The control system design is much more complicated than that of conventional aircraft due to its large attitude maneuvers and a large amount of uncertainty in ascent and descent modes. In order to provide accurate guidance and attitude tracking, the controller must be robust to external unknown

  15. Organization of computer systems: the fixed plus variable structure computer

    Microsoft Academic Search

    Gerald Estrin

    1960-01-01

    The past decade has seen the development of productive fast electronic digital computers. Significant problems have been solved and significant numerical experiments have been executed. Moreover, as expected, a growing number of important problems have been recorded which are not practicably computable by existing systems. These latter problems have provided the incentive for the present development of several large scale

  16. Refined Instrumental Variable methods for closed-loop system identification

    E-print Network

    Paris-Sud XI, Université de

    Box-Jenkins (BJ) model, where the plant and the noise models are not constrained to have common the system operates in closed-loop. Several noise models required for the design of optimal prefilters the identification of a linear (ARX) predictor combined with an ARMA noise model in a closed-loop framework

  17. Evolving Variable Plasticity in Neural Systems JOHN A. BULLINARIA

    E-print Network

    Bullinaria, John

    that ``you cannot teach old dogs new tricks''. This might not be totally true, but there is certainly for this is that the necessary resources are depleted or removed early in life, leaving little for the ``new tricks'' later on neurons. In the human accommodation (eye focussing) system, for example, we have blur being processed

  18. Design of antilock braking system based on variable structure control

    Microsoft Academic Search

    Li Junwei; Wang Jian

    2009-01-01

    Antilock braking system (ABS) is an important part to improve the automobile's active safety. In general, ABS is designed to achieve maximum negative acceleration by preventing the wheels from locking. Researches show that the friction between road and tire is a nonlinear function of wheel slip. In this paper, to deal with the strong nonlinearity in the design of ABS

  19. Drive system for the retraction/extension of variable diameter rotor systems

    NASA Technical Reports Server (NTRS)

    Gmirya, Yuriy (Inventor)

    2003-01-01

    A drive system for a variable diameter rotor (VDR) system includes a plurality of rotor blade assemblies with inner and outer rotor blade segments. The outer blade segment being telescopically mounted to the inner blade segment. The VDR retraction/extension system includes a drive housing mounted at the root of each blade. The housing supports a spool assembly, a harmonic gear set and an electric motor. The spool assembly includes a pair of counter rotating spools each of which drive a respective cable which extends through the interior of the inboard rotor blade section and around a pulley mounted to the outboard rotor blade section. In operation, the electric motor drives the harmonic gear set which rotates the counter rotating spools. Rotation of the spools causes the cables to be wound onto or off their respective spool consequently effecting retraction/extension of the pulley and the attached outboard rotor blade section relative the inboard rotor blade section. As each blade drive system is independently driven by a separate electrical motor, each independent VDR blade assembly is independently positionable.

  20. Optical mass memory system (AMM-13). AMM-13 system segment specification

    NASA Technical Reports Server (NTRS)

    Bailey, G. A.

    1980-01-01

    The performance, design, development, and test requirements for an optical mass data storage and retrieval system prototype (AMM-13) are established. This system interfaces to other system segments of the NASA End-to-End Data System via the Data Base Management System segment and is designed to have a storage capacity of 10 to the 13th power bits (10 to the 12th power bits on line). The major functions of the system include control, input and output, recording of ingested data, fiche processing/replication and storage and retrieval.

  1. Enhanced vibration energy harvesting using dual-mass systems Xiudong Tang, Lei Zuo n

    E-print Network

    Zuo, Lei

    Enhanced vibration energy harvesting using dual-mass systems Xiudong Tang, Lei Zuo n Department-mass vibration energy harvester, where two masses are connected in series with the energy transducer and spring, is proposed and analyzed in this paper. The dual-mass vibration energy harvester is proved to be able

  2. Internal combustion engine air intake system with variable effective length

    SciTech Connect

    Wada, H.; Horio, K.; Abe, K.

    1988-04-19

    An air intake system for feeding intake air to combustion chambers of a multicylinder internal combustion engine having two groups of longitudinally spaced engine cylinders is described comprising: a. a longitudinally extending surge tank positioned adjacent the engine cylinders; b. flow control valve means for opening and closing the aperture, the flow control valve means including a butterfly valve pivotally mounted in the aperture of the wall extension of the extension portion; and c. actuator means responsive to engine operating conditions for controlling opening and closing of the butterfly valve to vary the extent of flow communication between the volumetric chambers through the aperture, thereby varying the effective length of the intake system with engine operating conditions.

  3. Zero and root loci of disturbed spring–mass systems

    PubMed Central

    Lecomte, Christophe

    2014-01-01

    Models consisting of chains of particles that are coupled to their neighbours appear in many applications in physics or engineering, such as in the study of dynamics of mono-atomic and multi-atomic lattices, the resonances of crystals with impurities and the response of damaged bladed discs. Analytical properties of the dynamic responses of such disturbed chains of identical springs and masses are presented, including when damping is present. Several remarkable properties in the location of the resonances (poles) and anti-resonances (zeros) of the displacements in the frequency domain are presented and proved. In particular, it is shown that there exists an elliptical region in the frequency–disturbance magnitude plane from which zeros are excluded and the discrete values of the frequency and disturbance at which double poles occur are identified. A particular focus is on a local disturbance, such as when a spring or damper is modified at or between the first and last masses. It is demonstrated how, notably through normalization, the techniques and results of the paper apply to a broad category of more complex systems in physics, chemistry and engineering. PMID:24711724

  4. Orbits and masses in the multiple system LHS 1070

    NASA Astrophysics Data System (ADS)

    Köhler, R.; Ratzka, T.; Leinert, Ch.

    2012-05-01

    Aims: We present a study of the orbits of the triple system LHS 1070, with the aim to determine individual masses of its components. Methods: Sixteen new relative astrometric positions of the three components in the K band were obtained with NACO at the VLT, Omega CASS at the 3.5 m telescope on Calar Alto, and other high-spatial-resolution instruments. We combined them with data from the literature and fit orbit models to the dataset. We derived an improved fit for the orbit of LHS 1070 B and C around each other, and an estimate for the orbit of B and C around A. Results: The orbits are nearly coplanar, with a misalignment angle of less than 10°. The masses of the three components are MA = 0.13...0.16 M?, MB = 0.077 ± 0.005 M?, and MC = 0.071 ± 0.004 M?. Therefore, LHS 1070 C is certainly, and LHS 1070 B probably a brown dwarf. Comparison with theoretical isochrones shows that LHS 1070 A is either fainter or more massive than expected. One possible explanation would be that it is a binary. However, the close companion reported previously could not be confirmed. Based on observations collected at the European Southern Observatory, Chile, proposals number 60.A-9026, 66.C-0219, 67.C-0354, 68.C-0539, 70.C-0476, 072.C-0022, 074.C-0637, 078.C-0386, 380.C-0179, 382.C-0324, and 382.C-0329.

  5. Orbits and Masses in the multiple system LHS 1070

    E-print Network

    Köhler, R; Leinert, Ch

    2012-01-01

    We present a study of the orbits of the triple system LHS1070, with the aim to determine individual masses of its components. Sixteen new relative astrometric positions of the three components in the K band were obtained with NACO at the VLT, Omega CASS at the 3.5m telescope on Calar Alto, and other high-spatial-resolution instruments. We combine them with data from the literature and fit orbit models to the dataset. We derive an improved fit for the orbit of LHS1070B and C around each other, and an estimate for the orbit of B and C around A. The orbits are nearly coplanar, with a misalignment angle of less than 10{\\deg}. The masses of the three components are M_A = 0.13 - 0.16 Msun, M_B = 0.077+/-0.005 Msun, and M_C = 0.071+/-0.004 Msun. Therefore, LHS1070C is certainly, and LHS1070B probably a brown dwarf. Comparison with theoretical isochrones shows that LHS1070A is either fainter or more massive than expected. One possible explanation would be that it is a binary. However, the close companion reported pre...

  6. Automatically Finding the Control Variables for Complex System Behavior

    NASA Technical Reports Server (NTRS)

    Gay, Gregory; Menzies, Tim; Davies, Misty; Gundy-Burlet, Karen

    2010-01-01

    Testing large-scale systems is expensive in terms of both time and money. Running simulations early in the process is a proven method of finding the design faults likely to lead to critical system failures, but determining the exact cause of those errors is still time-consuming and requires access to a limited number of domain experts. It is desirable to find an automated method that explores the large number of combinations and is able to isolate likely fault points. Treatment learning is a subset of minimal contrast-set learning that, rather than classifying data into distinct categories, focuses on finding the unique factors that lead to a particular classification. That is, they find the smallest change to the data that causes the largest change in the class distribution. These treatments, when imposed, are able to identify the factors most likely to cause a mission-critical failure. The goal of this research is to comparatively assess treatment learning against state-of-the-art numerical optimization techniques. To achieve this, this paper benchmarks the TAR3 and TAR4.1 treatment learners against optimization techniques across three complex systems, including two projects from the Robust Software Engineering (RSE) group within the National Aeronautics and Space Administration (NASA) Ames Research Center. The results clearly show that treatment learning is both faster and more accurate than traditional optimization methods.

  7. Next generation of food allergen quantification using mass spectrometric systems.

    PubMed

    Koeberl, Martina; Clarke, Dean; Lopata, Andreas L

    2014-08-01

    Food allergies are increasing worldwide and becoming a public health concern. Food legislation requires detailed declarations of potential allergens in food products and therefore an increased capability to analyze for the presence of food allergens. Currently, antibody-based methods are mainly utilized to quantify allergens; however, these methods have several disadvantages. Recently, mass spectrometry (MS) techniques have been developed and applied to food allergen analysis. At present, 46 allergens from 11 different food sources have been characterized using different MS approaches and some specific signature peptides have been published. However, quantification of allergens using MS is not routinely employed. This review compares the different aspects of food allergen quantification using advanced MS techniques including multiple reaction monitoring. The latter provides low limits of quantification for multiple allergens in simple or complex food matrices, while being robust and reproducible. This review provides an overview of current approaches to analyze food allergens, with specific focus on MS systems and applications. PMID:24824675

  8. Vibrating Systems with Singular Mass-Inertia Matrices

    NASA Technical Reports Server (NTRS)

    Balakrishnan, A. V.

    1996-01-01

    Vibrating systems with singular mass-inertia matrices arise in recent continuum models of Smart Structures (beams with PZT strips) in assessing the damping attainable with rate feedback. While they do not quite yield 'distributed' controls, we show that they can provide a fixed nonzero lower bound for the damping coefficient at all mode frequencies. The mathematical machinery for modelling the motion involves the theory of Semigroups of Operators. We consider a Timoshenko model for torsion only, a 'smart string,' where the damping coefficient turns out to be a constant at all frequencies. We also observe that the damping increases initially with the feedback gain but decreases to zero eventually as the gain increases without limit.

  9. Science review: Genetic variability in the systemic inflammatory response

    PubMed Central

    Waterer, Grant W; Wunderink, Richard G

    2003-01-01

    The present review discusses recent studies that have identified genetic differences in inflammatory proteins associated with different phenotypic presentations of systemic inflammation. Basic genetic terminology is defined. Implications of genetic influences on the inflammatory response are discussed. The published associations of specific polymorphisms in antigen recognition pathways, proinflammatory cytokines, anti-inflammatory cytokines, and effector molecules are reviewed. The strongest and most consistent associations thus far have been with the tumor necrosis factor, lymphotoxin-?, and IL-1 receptor antagonist polymorphisms. However, large, phenotypically detailed studies are required to address all of the other potential polymorphisms in inflammatory molecule genes and their interactions. PMID:12930554

  10. Model-specific variability of ocean biogeochemistry in Earth system models

    NASA Astrophysics Data System (ADS)

    Keller, Kathrin; Joos, Fortunat

    2015-04-01

    Climate models are the measure of choice when observations are scarce or for questions concerning the future. However, when working with models, not only the internal variability of the climate system is of importance. The specific variability of the models has also to be taken into account, especially when they are compared on a quantitative scale. Till now the focus of multi-model or model ensemble studies has been on the research question itself, inter-model differences were of minor importance or completely neglected. Here we present results based on both control runs and transient simulations with a range of different Earth system models. One finding is that, for variables such as surface DIC, pH and pCO2, the inter-model spread of a model ensemble is larger for the inter-annual variability than for the anthropogenic trend.

  11. Distinguishing Loss of Structure from Subunit Dissociation for Protein Complexes with Variable Temperature Ion Mobility Mass Spectrometry.

    PubMed

    Pacholarz, Kamila J; Barran, Perdita E

    2015-06-16

    The thermal stability and strength of interactions in proteins are commonly measured using isothermal calorimetry and differential scanning calorimetry providing a measurement that averages over structural transitions that occur as the proteins melt and dissociate. Here, we apply variable temperature ion mobility mass spectrometry (VT-IM-MS) to study the effect of temperature on the stability and structure of four multimeric protein complexes. VT-IM-MS is used here to investigate the change in the conformation of model proteins, namely, transthyretin (TTR), avidin, concanavalin A (conA), and human serum amyloid P component (SAP) at elevated temperatures prior, during, and after dissociation up to 550 K. As the temperature of the buffer gas is increased from 300 to 350 K, a small decrease in the collision cross sections ((DT)CCSHe) of protein complexes from the values at room temperature is observed, and is associated with complex compaction occurring close to the reported solution Tm. At significantly higher temperatures, each protein complex undergoes an increase in (DT)CCSHe and in the width of arrival time distributions (ATD), which is attributed to extensive protein unfolding, prior to ejection of a highly charged monomer species. This approach allows us to decouple the distinct gas phase melting temperature (Tm) from the temperature at which we see subunit dissociation. The thermally induced dissociation (TID) mechanism is observed to initially proceed via the so-called "typical" (CID) dissociation route. Interestingly, data collected at higher analysis temperature suggests that the TID process might be adapting more "atypical" dissociation route. PMID:25993423

  12. An automated system for the analysis of variable temperature radioluminescence

    NASA Astrophysics Data System (ADS)

    Poolton, N. R. J.; Bulur, E.; Wallinga, J.; Bøtter-Jensen, L.; Murray, A. S.; Willumsen, F.

    2001-09-01

    Radioluminescence (RL, i.e. prompt luminescence emitted during exposure to ionizing radiation) is used for analysing luminescence emission processes and has been proposed as a method for determining received radiation doses in both natural and synthetic radiation dosimeters. We describe here an automated system capable of both multi-sample RL analysis and comparative studies using traditional thermoluminescence (TL) and optically stimulated luminescence (OSL) methods. The radioluminescence unit is intended as an attachment for the existing automated Risø TL-OSL systems; it delivers a dose rate of 4.5 Gy/min to materials such as quartz, using an 80 mCi 90Sr/ 90Y ?-source. The unit enables the measurement of RL in the temperature range 25-500°C using both continuous and pulsed radiation exposures. Measurements are fully automated, allowing up to 48 samples to be measured in any one experimental run. Results from several experiments are presented for two representative dosimeters; natural quartz and artificial Al 2O 3:C. These experiments include investigation of the dose and temperature dependence of RL, pulsed RL, and spectrally resolved RL; comparisons with TL are also made.

  13. The MUSCLES Treasury Survey: Measurements of the Ultraviolet Spectral Characteristics of Low-mass Exoplanetary Systems

    NASA Astrophysics Data System (ADS)

    France, Kevin

    2014-10-01

    It has recently been discovered that 10 - 50% of M dwarfs host Earth-size planets in their habitable zones. Furthermore, the nearest potentially habitable super-Earths orbit M dwarfs, meaning that these systems likely represent our best chance to discover habitable worlds in the coming decade. The ultraviolet (UV) spectrum incident upon Earth-like planets drives the dissociation of water and CO2, the production of O2 and ozone, and may determine their ultimate habitability. At present, we lack the observational and theoretical basis to predict the energetic radiation spectrum (X-ray through UV) of an M dwarf. UV variability of low-mass exoplanet host stars, in particular the possibly sterilizing effect of flare activity, is almost completely unexplored observationally. This proposal aims to acquire the critical UV observations of low-mass host stars now, providing a treasury database for studies of exemplary nearby exoplanetary systems and potentially habitable worlds not yet discovered. Building on our successful pilot program of spectrally and temporally resolved UV radiation fields, we propose the MUSCLES Treasury Survey: a UV survey of nearby low-mass exoplanetary host stars. Using HST-COS and STIS, we will observe the 1150 - 5700A fluxes, reconstruct the important Ly-alpha emission lines, and use these data to estimate the extreme-UV (200 - 912A) irradiances incident upon exoplanetary atmospheres. The UV data will be complemented with contemporaneous X-ray and ground-based observations as well as new M dwarf atmosphere models to constrain atmospheric heating rates and provide a baseline for long-term ground-based studies of these systems.

  14. Minimum fuel control of a vehicle with a continuously variable transmission. [control system simulation

    NASA Technical Reports Server (NTRS)

    Burghart, J. H.; Donoghue, J. F.

    1980-01-01

    The design and evaluation of a control system for a sedan with a heat engine and a continuously variable transmission, is considered in a effort to minimize fuel consumption and achieve satisfactory dynamic response of vehicle variables as the vehicle is driven over a standard driving cycle. Even though the vehicle system was highly nonlinear, attention was restricted to linear control algorithms which could be easily understood and implemented demonstrated by simulation. Simulation results also revealed that the vehicle could exhibit unexpected dynamic behavior which must be taken into account in any control system design.

  15. Initial layer phenomena for a class of singular perturbed nonlinear system with slow variables

    Microsoft Academic Search

    Huang Wei-zhang; Chen Yu-sen

    2004-01-01

    The initial layer phenomena for a class of singular perturbed nonlinear system with slow variables are studied. By introducing\\u000a stretchy variables with different quantity levels and constructing the correction term of initial layer with different “thickness”,\\u000a the N-order approximate expansion of perturbed solution concerning small parameter is obtained, and the “multiple layer” phenomena\\u000a of perturbed solutions are revealed. Using the

  16. Variability within the Seychelles Cytoplasmic Incompatibility System in Drosophila Simulans

    PubMed Central

    Mercot, H.; Llorente, B.; Jacques, M.; Atlan, A.; Montchamp-Moreau, C.

    1995-01-01

    In Drosophila simulans, we described a cytoplasmic incompatibility (CI) system (Seychelles) restricted to insular populations that harbor the mitochondrial type SiI. Since then, these populations have been shown to be heterogeneous, some being infected by one Wolbachia genetic variant only (wHa), while others are infected simultaneously by wHa and by another variant (wNo) always found in association with wHa. We have experimentally obtained two D. simulans strains only infected by the wNo variant. This variant determines its own cytoplasmic incompatibility type. In particular, the cross between wNo-bearing flies and wHa-bearing ones is bidirectionally incompatible. The Seychelles CI type, stricto sensu, is distinguished by being determined by the simultaneous presence of two Wolbachia variants that we found to be mutually incompatible. In addition, we observed incomplete maternal transmission of the Wolbachia. PMID:8582608

  17. System for throttling and compensation for variable feedstock properties

    DOEpatents

    Meyer, John W. (Palo Alto, CA)

    1981-01-01

    Apparatus is shown for adjusting the feed rate of pulverized feed material into a pressurized container. The apparatus also has utility for compensating for variations in the permeability of the feed material. A rotor that includes sprues with provision for controlling the pressure distribution along the sprues is located within the pressurized container. The rotor hub is connected to a drive means and a material supply means which extend through the wall of the container. A line for controlling pressure along the sprues by gas injection is connected to a chamber between sections of the sprue for controlling gas pressure at that point. The gas pressure control line is connected to a pressurized gas source and a control system external to the rotor.

  18. System for throttling and compensation for variable feedstock properties

    DOEpatents

    Meyer, J. W.

    1981-05-05

    Apparatus is shown for adjusting the feed rate of pulverized feed material into a pressurized container. The apparatus also has utility for compensating for variations in the permeability of the feed material. A rotor that includes sprues with provision for controlling the pressure distribution along the sprues is located within the pressurized container. The rotor hub is connected to a drive means and a material supply means which extend through the wall of the container. A line for controlling pressure along the sprues by gas injection is connected to a chamber between sections of the sprue for controlling gas pressure at that point. The gas pressure control line is connected to a pressurized gas source and a control system external to the rotor. 10 figs.

  19. System mass optimization of hydrogen\\/oxygen based regenerative fuel cells for geosynchronous space missions

    Microsoft Academic Search

    S. Hauff; K. Bolwin

    1992-01-01

    An intrinsic advantage of the RFC system permits design optimization by varying the current density of the electrolyzer and the fuel cell stack and evaluating the masses of the two subsystems. Mass optimization has been carried out considering a dedicated electrolyzer and fuel cell system, together with the masses of a photovoltaic array, a radiator, and the required storage. The

  20. Evaluation of Application Accuracy and Performance of a Hydraulically Operated Variable-Rate Aerial Application System

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An aerial variable-rate application system consisting of a DGPS-based guidance system, automatic flow controller, and hydraulically controlled pump/valve was evaluated for response time to rapidly changing flow requirements and accuracy of application. Spray deposition position error was evaluated ...

  1. FUZZY LOGIC BASED INTELLIGENT CONTROL OF A VARIABLE SPEED CAGE MACHINE WIND GENERATION SYSTEM

    EPA Science Inventory

    The paper describes a variable-speed wind generation system where fuzzy logic principles are used to optimize efficiency and enhance performance control. A squirrel cage induction generator feeds the power to a double-sided pulse width modulated converter system which either pump...

  2. Smart base isolated buildings with variable friction systems:H? controller and SAIVF device

    Microsoft Academic Search

    S. Narasimhan; S. Nagarajaiah

    2006-01-01

    SUMMARY A new control algorithm is developed for reducing the response of smart base isolated buildings with variable friction semiactive control systems in near-fault earthquakes. The central idea of the control algorithm is to design a H? controller for the structural system and use this controller to determine the optimum control force in the semiactive device. The H? controller is

  3. DFIG-Based Power Generation System With UPS Function for Variable-Speed Applications

    Microsoft Academic Search

    Grzegorz Iwanski; Wlodzimierz Koczara

    2008-01-01

    The power generation system with a doubly fed induction generator (DFIG), which can be used as an autonomous power system after the loss of mains in a distributed generation network, is described. After the mains outage, a fixed frequency and an amplitude of the output voltage are obtained, despite the variable rotor speed. For this reason, it can be successfully

  4. Classical spectrum generating algebra of the Kepler-Coulomb system and action-angle variables

    NASA Astrophysics Data System (ADS)

    Kuru, ?.; Negro, J.

    2012-01-01

    The classical spectrum generating algebra for the one-dimensional Kepler-Coulomb system is computed and a set of two corresponding constants of motion depending explicitly on time is obtained. Such constants supply the solution to the motion in an algebraic way. The connection of the spectrum generating algebra and the action-angle variables of the system is also shown.

  5. Analytical investigation of the pericyclic variable-speed transmission system for helicopter main-gearbox

    Microsoft Academic Search

    Zihni Burcay Saribay

    2009-01-01

    In the recent years, there has been significant interest in the new developments and improvements of the rotorcraft transmission systems. The main goal of the rotorcraft transmission research is the reduction of overall gear train weight while maintaining the efficiency and reliability. The Pericyclic Variable-Speed Transmission (PVT) System is one of the potential candidates of the future rotorcraft drive trains

  6. On velocity profiles and stresses in sheared and vibrated granular systems under variable gravity

    E-print Network

    Kondic, Lou

    On velocity profiles and stresses in sheared and vibrated granular systems under variable gravity that include realistic modeling of physical system boundaries to determine the influence of gravity on velocity, and sheared by a rotated upper wall. In addition to Earth gravity, we consider other gravitational fields

  7. Heating control strategy in fresh air processor matched with variable refrigerant flow air conditioning system

    Microsoft Academic Search

    Qiu Tu; Shoubo Mao; Yuhai Feng; Defang Guo

    2011-01-01

    The fresh air processor (FAP), matched with the variable refrigerant flow air conditioning system (VRF AC), has been developed. Two control methods were adopted to control the system running and air outlet temperature, contrastively. The first method is that the running frequency in heating mode is adjusted in terms of the ordinary control method of VRF, i.e., constant condensation temperature.

  8. Heating control strategy for variable refrigerant flow air conditioning system with multi-module outdoor units

    Microsoft Academic Search

    Qiu Tu; Ziping Feng; Shoubo Mao; Kaijun Dong; Rui Xiao; Wenji Song

    2010-01-01

    The heating control strategy is key technology for stable and reliable heating operation of variable refrigerant flow air conditioning system with multi-module outdoor units. The synoptic control strategy is that the host module coordinates the system operation and adjusts the operation frequency of every module based on equal frequency allocation principle for suction pressure balance among modules. The heating control

  9. Designing Reliable Systems from Unreliable Components: The Challenges of Transistor Variability and Degradation

    Microsoft Academic Search

    Shekhar Y. Borkar

    2005-01-01

    As technology scales, variability in transistor performance continues to increase, making transistors less and less reliable. This creates several challenges in building reliable systems, from the unpredictability of delay to increasing leakage current. Finding solutions to these challenges require a concerted effort on the part of all the players in a system design. This article discusses these effects and proposes

  10. Characterizing Vertical Mass Flux Profiles in Aeolian Saltation Systems 

    E-print Network

    Farrell, Eugene

    2012-07-16

    This dissertation investigates characteristics of the vertical distributions of mass flux observed in field and laboratory experiments. Thirty vertical mass flux profiles were measured during a field experiment in Jericoacoara, Brazil from October...

  11. Reco level Smin and subsystem Smin: improved global inclusive variables for measuring the new physics mass scale in MET events at hadron colliders

    SciTech Connect

    Konar, Partha; /Florida U.; Kong, Kyoungchul; /SLAC; Matchev, Konstantin T.; Park, Myeonghun; /Florida U.

    2011-08-11

    The variable {radical}s{sub min} was originally proposed in [1] as a model-independent, global and fully inclusive measure of the new physics mass scale in missing energy events at hadron colliders. In the original incarnation of {radical}s{sub min}, however, the connection to the new physics mass scale was blurred by the effects of the underlying event, most notably initial state radiation and multiple parton interactions. In this paper we advertize two improved variants of the {radical}s{sub min} variable, which overcome this problem. First we show that by evaluating the {radical}s{sub min} variable at the RECO level, in terms of the reconstructed objects in the event, the effects from the underlying event are significantly diminished and the nice correlation between the peak in the {radical}s{sub min}{sup (reco)} distribution and the new physics mass scale is restored. Secondly, the underlying event problem can be avoided altogether when the {radical}s{sub min} concept is applied to a subsystem of the event which does not involve any QCD jets. We supply an analytic formula for the resulting subsystem {radical}s{sub min}{sup (sub)} variable and show that its peak exhibits the usual correlation with the mass scale of the particles produced in the subsystem. Finally, we contrast {radical}s{sub min} to other popular inclusive variables such as H{sub T}, M{sub Tgen} and M{sub TTgen}. We illustrate our discussion with several examples from supersymmetry, and with dilepton events from top quark pair production.

  12. Mass Deacidification Systems: Planning and Managerial Decision Making.

    ERIC Educational Resources Information Center

    Turko, Karen

    Library administrators, faced with the problems of acid-paper deterioration, are examining mass deacidification procedures. Mass deacidification of acidic books while they are still physically sound and not yet brittle is the most cost-effective corrective action to extend the life of the paper. There are currently at least five mass

  13. Identification of a wide, low-mass multiple system containing the brown dwarf 2MASS J0850359+105716

    E-print Network

    Faherty, Jacqueline K.

    We report our discovery of NLTT 20346 as an M5+M6 companion system to the tight binary (or triple) L dwarf 2MASS J0850359+105716. This nearby (~31 pc), widely separated (~7700 AU) quadruple system was identified through a ...

  14. THE EVOLUTION OF PLANETARY SYSTEMS WITH TIME-DEPENDENT STELLAR MASS LOSS RATES

    E-print Network

    Bloch, Anthony

    THE EVOLUTION OF PLANETARY SYSTEMS WITH TIME-DEPENDENT STELLAR MASS LOSS RATES Kassandra R systems, this paper generalizes previous studies of orbital evolution in planetary systems with stellar evolution for two planet systems with stellar mass loss. Here we focus on a simple model consisting

  15. Cold Mass Support System for he D0 Solenoid

    SciTech Connect

    Squires, B.; /Fermilab

    1993-08-09

    The support system is designed to support the gravitational, magnetic, and thermal contraction loads associated with the cold mass weighing 1.46 metric tons (3210 Ibm). The loading constraints are listed in Table 1. The support system consists of axial members (axial supports) to provide longitudinal stiffness and nearly tangential members (radial supports) to provide radial stiffness. The members connect the outer support cylinder to the flat annular bulkheads of the vacuum vessel. See Figures 1 through 3 for additional details on the supports. Six axial compression-tension supports are located on the chimney end of the cryostat only. Six radial tension supports are located on each end. Both types of members are fabricated of Inconel 718 and have a design safety factor of 4 on the ultimate strength at 300 K. The axial supports are also designed for a buckling safety factor of 4 for the operating loads. Shipping stops will be installed to prevent the axial supports from going into compression during transportation. Axial and radial contraction of the coil support cylinder is accommodated by spherical bearings on both ends ofeach support member.

  16. Gerotor and bearing system for whirling mass orbital vibrator

    DOEpatents

    Brett, James Ford; Westermark, Robert Victor; Turner, Jr., Joey Earl; Lovin, Samuel Scott; Cole, Jack Howard; Myers, Will

    2007-02-27

    A gerotor and bearing apparatus for a whirling mass orbital vibrator which generates vibration in a borehole. The apparatus includes a gerotor with an inner gear rotated by a shaft having one less lobe than an outer gear. A whirling mass is attached to the shaft. At least one bearing is attached to the shaft so that the bearing engages at least one sleeve. A mechanism is provided to rotate the inner gear, the mass and the bearing in a selected rotational direction in order to cause the mass, the inner gear, and the bearing to backwards whirl in an opposite rotational direction. The backwards whirling mass creates seismic vibrations.

  17. Direct Torque Control Strategy for a Variable Speed Wind Energy Conversion System Associated to a Flywheel Energy Storage System

    Microsoft Academic Search

    K. Idjdarene; D. Rekioua; T. Rekioua; A. Tounzi

    2009-01-01

    In this paper, we present a variable speed wind induction generator associated to a flywheel energy storage system. Direct torque control strategy for an induction generator used in the flywheel energy storage system, is applied. Both rotor flux and DC bus voltage are regulated by the applied of the standard switching table for an operation in the 4 quadrants. This

  18. A review on the integration of wind farms with variable speed wind turbine systems into power systems

    Microsoft Academic Search

    Yuan-zhang Sun; Jin Lin; Guo-jie Li; Xiong Li

    2009-01-01

    With the development of wind energy and power electric control technology, more wind farms with variable speed wind turbine systems (VSWTS) are integrated into power grids. While VSWTSs improve the stability and power quality of systems, several new problems are introduced in power grid. This paper provides an overview to the relevant latest research issues related to the integration of

  19. Description and test results of a variable speed, constant frequency generating system

    SciTech Connect

    Brady, F.J.

    1985-12-01

    The variable-speed, constant frequency generating system developed for the Mod-O wind turbine is presented. The development of this system occurred in several stages. This report describes the system as it existed at the conclusion of the project. The cycloconverter control circuit is described in detail. The major addition to the control circuit, field-oriented control, is also described. Laboratory test and actual wind turbine test results are included.

  20. MODELING AND EXPERIMENT ANALYSIS OF VARIABLE REFRIGERANT FLOW AIR-CONDITIONING SYSTEMS

    Microsoft Academic Search

    Xuhui Wang; Jianjun Xia; Xiaoliang Zhang; Sumio Shiochi; Chen Peng; Yi Jiang

    This study developed a component-based gray-box model for variable refrigerant flow (VRF) air- conditioning systems to simulate and predict the performance and energy consumption of VRF system in cooling condition. Results from the testing of Daikin's 10HP VRV system with six indoor units, as well as the manufacturer's data, were used to fit the key parameters of each component in

  1. The Attributes of a Variable-Diameter Rotor System Applied to Civil Tiltrotor Aircraft

    NASA Technical Reports Server (NTRS)

    Brender, Scott; Mark, Hans; Aguilera, Frank

    1996-01-01

    The attributes of a variable diameter rotor concept applied to civil tiltrotor aircraft are investigated using the V/STOL aircraft sizing and performance computer program (VASCOMP). To begin, civil tiltrotor viability issues that motivate advanced rotor designs are discussed. Current work on the variable diameter rotor and a theoretical basis for the advantages of the rotor system are presented. The size and performance of variable diameter and conventional tiltrotor designs for the same baseline mission are then calculated using a modified NASA Ames version of VASCOMP. The aircraft are compared based on gross weight, fuel required, engine size, and autorotative performance for various hover disk loading values. Conclusions about the viability of the resulting designs are presented and a program for further variable diameter rotor research is recommended.

  2. Two-variable Wilson polynomials and the generic superintegrable system on the 3-sphere

    E-print Network

    Kalnins, E G; Jr.,; Post, S

    2010-01-01

    We show that the symmetry operators for the quantum superintegrable system on the 3-sphere with generic 4-parameter potential form a closed quadratic algebra with 6 linearly independent generators that closes at order 6 (as differential operators). Further there is an algebraic relation at order 8 expressing the fact that there are only 5 algebraically independent generators. We work out the details of modeling physically relevant irreducible representations of the quadratic algebra in terms of divided difference operators in two variables. We determine several ON bases for this model including spherical and cylindrical bases. These bases are expressed in terms of two variable Wilson and Racah polynomials with arbitrary parameters, i.e., limits as q goes to 1 of the two variable Macdonald-Koornwinder polynomials. The generators for the quadratic algebra are expressed in terms of recurrence operators for the one-variable Wilson polynomials. The quadratic algebra structure breaks the degeneracy of the space of ...

  3. A study of engine variable geometry systems for an advanced high subsonic long range commercial aircraft

    NASA Technical Reports Server (NTRS)

    Compagnon, M. A.

    1973-01-01

    Several variable geometry high Mach inlet concepts, aimed at meeting a system noise objective of 15 EPNdB below FAR part 36, for a long range, Mach 0.9 advanced commercial transport are assessed and compared to a fixed geometry inlet with multiple splitters. The effects of a variable exhaust nozzle (mixed exhaust engine) on noise, inlet geometry requirements, and economics are also presented. The best variable geometry inlet configuration identified is a variable cowl design which relies on a high throat Mach number for additional inlet noise suppression only at takeoff, and depends entirely on inlet wall treatment for noise suppression at approach power. Relative economic penalties as a function of noise level are also presented.

  4. Accumulation Rate Variability and Winter Mass Balance Estimates using High Frequency Ground-Penetrating Radar and Snow Pit Stratigraphy on the Juneau Icefield, Alaska

    NASA Astrophysics Data System (ADS)

    Braddock, S. S.; Boucher, A. L.; Sandler, H. C.; McNeil, C.; Campbell, S. W.; Kreutz, K. J.

    2012-12-01

    In July 2012, 200 km of 400 MHz ground-penetrating radar (GPR) profiles were collected across the Juneau Icefield, Alaska. The goal was to determine if spatial accumulation rate variability and winter mass balance estimates could be improved by linking stratigraphic features between yearly-excavated snow pits through GPR. Profiles were collected along the centerline and cross sections of the main branch, northwest, and Southwest branch of the Taku Glacier as well as the Mathes, Llewellyn, and Demorest Glaciers. Over 650 km^2 of area and 1000 m of elevation range were covered during this pilot project linking sixteen snow pits with GPR data across the icefield. The field work was conducted as part of the Juneau Icefield Research Program (JIRP) with hopes of continuing this method in future years if first year results show promise. As an annually operated field research and education program, JIRP creates a unique opportunity to provide significant future contributions to Alaska mass balance records if the program is continued. Signal penetration reached ? 25 m with maximum depths reached at higher elevations of the icefield. Conversely, minimal penetration occurred in wetter regions at lower elevations, likely caused by volume scattering from free water within the firn and ice. Ice lenses and the annual layer located in mass balance snow pits correlated well with continuous stratigraphy imaged in GPR profiles suggesting that the lenses are relatively uninterrupted across the icefield and that GPR may be an appropriate tool for extrapolating point mass balance pit depths in this part of Alaska. The Northwest and Southwest Branches of the Taku Glacier show a strong stratigraphic thinning gradient, west to east; the main trunk of the Taku Glacier which originates from the Mathes-Llewellyn ice divide showed a similar thinning from the divide to the ELA. The thinning displayed by all three glacier systems matches a typical gradient from accumulation zone to ELA. However, it is also likely that a local influx of accumulation at the higher elevations of the Southwest and Northwest Branches result from their close proximity of the ocean. Beyond mass balance estimates, radar profiles also revealed ablation horizons underlying the annual layer near the ELA. Monitoring the location of this ablation horizon relative to the annual balance reflector may be helpful in quantifying changes in the ELA at the end of each previous melt season. Perched water tables were also imaged in several locations which may be suitable for future hydrological studies focused on delineation of sub-glacial drainage systems and their impact on local glacier dynamics. This is a particularly interesting finding considering the unprecedented recent jokulhlaup of the Mendenhall Glacier and re-routing of the primary water drainage at the Llewellyn Glacier terminus in 2011.

  5. Entanglement detection for bipartite systems with continuous variables in non-Markovian baths

    SciTech Connect

    Duan Hongguang; Liang Xianting [Department of Physics and Institute of Modern Physics, Ningbo University, Ningbo 315211 (China)

    2011-03-15

    By using the dynamics described with the quantum Langevin equation and the inseparability criterion for continuous-variable systems [L.-M. Duan, G. Giedke, J. I. Cirac, and P. Zoller, Phys. Rev. Lett. 84, 2722 (2000).], we discuss a method to judge whether entanglement exists in the evolutions of bipartite systems with continuous variables in their baths. By using this method we investigate a nontrivial example, namely, we judge when the entanglement exists in the evolution of the two coupled anharmonic oscillators in their environments.

  6. AeroPropulsoServoElasticity: Dynamic Modeling of the Variable Cycle Propulsion System

    NASA Technical Reports Server (NTRS)

    Kopasakis, George

    2012-01-01

    This presentation was made at the 2012 Fundamental Aeronautics Program Technical Conference and it covers research work for the Dynamic Modeling of the Variable cycle Propulsion System that was done under the Supersonics Project, in the area of AeroPropulsoServoElasticity. The presentation covers the objective for the propulsion system dynamic modeling work, followed by the work that has been done so far to model the variable Cycle Engine, modeling of the inlet, the nozzle, the modeling that has been done to model the affects of flow distortion, and finally presenting some concluding remarks and future plans.

  7. Rms-flux relation and fast optical variability simulations of the nova-like system MV Lyr

    NASA Astrophysics Data System (ADS)

    Dobrotka, A.; Mineshige, S.; Ness, J.-U.

    2015-03-01

    The stochastic variability (flickering) of the nova-like system (subclass of cataclysmic variable) MV Lyr yields a complicated power density spectrum with four break frequencies. Scaringi et al. analysed high-cadence Kepler data of MV Lyr, taken almost continuously over 600 d, giving the unique opportunity to study multicomponent Power Density Spectra (PDS) over a wide frequency range. We modelled this variability with our statistical model based on disc angular momentum transport via discrete turbulent bodies with an exponential distribution of the dimension scale. Two different models were used, a full disc (developed from the white dwarf to the outer radius of ˜1010 cm) and a radially thin disc (a ring at a distance of ˜1010 cm from the white dwarf) that imitates an outer disc rim. We succeed in explaining the two lowest observed break frequencies assuming typical values for a disc radius of 0.5 and 0.9 times the primary Roche lobe and an ? parameter of 0.1-0.4. The highest observed break frequency was also modelled, but with a rather small accretion disc with a radius of 0.3 times the primary Roche lobe and a high ? value of 0.9 consistent with previous findings by Scaringi. Furthermore, the simulated light curves exhibit the typical linear rms-flux proportionality linear relation and the typical log-normal flux distribution. As the turbulent process is generating fluctuations in mass accretion that propagate through the disc, this confirms the general knowledge that the typical rms-flux relation is mainly generated by these fluctuations. In general, a higher rms is generated by a larger amount of superposed flares which is compatible with a higher mass accretion rate expressed by a larger flux.

  8. Relationships between 3-y longitudinal changes in body mass index, waist-to-hip ratio, and metabolic variables in an active French female population1'2

    Microsoft Academic Search

    Claire Bonithon-Kopp; Jocelyne Raison; Dominique Courbon; Genevieve Bonhomme; Bernard Guy-Grand

    Three-year longitudinal changes in body mass index (BMI), waist-to-hip ratio (WHR), and metabolic variables were examined in 209 active French women. For the entire group, a weak but significant positive association was found be- tween change in BMI and change in WHR. However, analysis of covariance according to the degree of abdominal fat distri- bution showed a heterogeneity ofthis association

  9. Optimal compensation of variable series capacitors for improved economic dispatch in power systems

    SciTech Connect

    Deng, W.; Lie, T.T. [Nanyang Technological Univ., Singapore (Singapore). School of Electrical and Electronic Engineering

    1995-12-31

    This paper presents the development of a mathematical model representation of variable series capacitors which also known as Flexible AC Transmission systems (FACTS) in power system economic dispatch. The objective of this research is to find the optimal locations of FACTS devices for improved economic dispatch. The proposed approach is based on the decomposition-coordination method and the network compensation technique. Taking the advantages of accumulated experience in power system optimization and the existence of the Optimal Power Flow (OPF) software, the software development cost for implementing the proposed algorithm is reduced. In this paper, digital simulation studies on small power systems with and without variable series capacitors were conducted respectively. The purpose of these simulation studies is to assess the effectiveness of the proposed algorithm in minimizing the operating cost and enhancing the system performance. The results of the simulation studies and the proposed algorithm are presented and discussed in greater detail in the paper.

  10. Effect of rainfall spatial variability and sampling on salinity prediction in an estuarine system

    NASA Astrophysics Data System (ADS)

    Habib, Emad; Larson, Boone F.; Nuttle, William K.; Rivera-Monroy, Victor H.; Nelson, Brian R.; Meselhe, Ehab A.; Twilley, Robert R.

    2008-02-01

    SummaryReliable and accurate forecasts of salinity changes are essential for the success of current and future management scenarios aimed at restoring and sustaining natural resources of coastal and estuarine ecosystems. Because of the physical complexity of such ecosystems, information on uncertainty associated with salinity forecasts should be assessed and incorporated into management and restoration decisions. This study focuses on the impact of spatial variability and limited sampling of rainfall on salinity prediction in an estuarine system. The analysis is conducted on the Barataria basin, which is a wetland-dominated estuarine system located directly west of the Mississippi Delta complex on the United States coast of south Louisiana. The basin has been experiencing significant losses of wetland at a rate of nearly 23 km 2/year. Radar-rainfall data with high spatial resolution are used to simulate various scenarios of hypothetical rain gauge sampling densities over the basin. A mass-balance hydrologic salinity model is used to assess the effect of reduced rainfall sampling on salinity prediction in the basin. The results indicated that, due to the critical role played by rainfall in determining the overall balance of the basin freshwater budget, a high degree of uncertainty exists in salinity predictions when using typical average rain gauge densities (e.g., 1.3 gauges/1000 km 2 in the US). These uncertainties decline sharply as the number of available gauges is increased beyond the typically available density. Uncertainties in salinity predictions in the Barataria basin are larger in inland locations and smaller near the mouth of the basin, where salinity conditions in the coastal waters of the Gulf of Mexico exert a large influence. Rainfall uncertainties also affected parameter estimation during model calibration, where the estimation of some parameters exhibited significant levels of bias and random scatter. The study highlights the necessity of improving rainfall monitoring especially in estuarine systems that are controlled by rainfall as a main source of freshwater and where the management of freshwater supply is a viable option.

  11. Determination of residual strength parameters of jointed rock masses using the GSI system

    Microsoft Academic Search

    M. Cai; P. K. Kaiser; Y. Tasaka; M. Minami

    2007-01-01

    The Geological Strength Index (GSI) system, proposed in 1995, is now widely used for the estimation of the rock mass strength and the rock mass deformation parameters. The GSI system concentrates on the description of two factors, rock structure and block surface conditions. The guidelines given by the GSI system are for the estimation of the peak strength parameters of

  12. Mass Measurement Using the Fixed Point of a Spring-Mass System with a Dynamic Vibration Absorber

    NASA Astrophysics Data System (ADS)

    Yamamoto, Satoru; Ishino, Yuji; Takasaki, Masaya; Mizuno, Takeshi

    A vibration-type measurement system characterized by the use of an undamped dynamic vibration absorber has been developed. However, inevitable damping in the absorber may cause measurement error. A new method of measuring mass is proposed to overcome this problem. The measurement system utilizes the fixed point of a mass-spring system with a dynamic vibration absorber so that the mass is estimated regardless of damping in the absorber. A phase-looked loop (PLL) is used to achieve tuning. The principle of measurement is described on the basis of a mathematical model. A measuring apparatus was designed and fabricated, and several of its basic characteristics were studied experimentally. Damping of the primary system was found to affect fixed point formation. By reducing the damping of the primary system by a voice coil motor, the measurement conditions were achieved. The efficacy of the apparatus was studied both analytically and experimentally. The measurement conditions were realized automatically by the PLL. Mass measurement was performed while the PLL was operated; the average measurement error was within 0.21 [%].

  13. On observer design for nonlinear Takagi-Sugeno systems with unmeasurable premise variable

    E-print Network

    Paris-Sud XI, Université de

    variables. The main result is established using the differential mean value theorem which provides a T-Sugeno systems, state estimation, dif- ferential mean value theorem, Lyapunov stability analysis, linear matrix-S representation of the differential equation generating the state estimation error. This allows to extend some

  14. On observer design for nonlinear Takagi-Sugeno systems with unmeasurable premise variable

    Microsoft Academic Search

    Dalil Ichalal; Benoit Marx; Jose Ragot; Didier Maquin

    2011-01-01

    In this paper, we propose a method for state estimation of nonlinear systems represented by Takagi- Sugeno (T-S) models with unmeasurable premise variables. The main result is established using the differential mean value theorem which provides a T-S representation of the differential equation generating the state estimation error. This allows to extend some results obtained in the case of measurable

  15. Variability of Soil-Structure System Frequencies during Strong Earthquake Shaking for a Group of

    E-print Network

    Southern California, University of

    procedures. INTRODUCTION The Earthquake Resistant Design Codes have evolved based on principles earthquake shaking is needed for further refinement of the existing and development of new design code1 Variability of Soil-Structure System Frequencies during Strong Earthquake Shaking for a Group

  16. Controller Design for a Manipulator Using Theory of Variable Structure Systems

    Microsoft Academic Search

    Kar-Keung D. Young

    1978-01-01

    A new control algorithm is developed for manipulators using the theory of variable structure systems. The control is designed so that a new type of state space trajectories called sliding mode exists. Due to delays, neglected small time constants, and other idealizations, ideal sliding modes as predicted by the theory do not exist. We have verified through hybrid simulation that

  17. Lack of agreement between gas exchange variables measured by two metabolic systems

    Microsoft Academic Search

    Djordje G. Jakovljevic; David Nunan; Gay Donovan; Lynette D. Hodges; Gavin R. H. Sandercock; David A. Brodie

    2008-01-01

    The purpose of this study was to assess the agreement and con- sistency between gas exchange variables measured by two online metabolic systems during an incremental exercise test. After obtaining local ethics approval and informed consent, 15 healthy subjects performed an incremental exercise test to voli- tional fatigue using the Bruce protocol. The Innocor (Innovision, Denmark) and CardiO2 (Medical Graphics,

  18. Variables which Differentiate Placement of Adolescents into Juvenile Justice or Mental Health Systems.

    ERIC Educational Resources Information Center

    Westendorp, Floyd; And Others

    1986-01-01

    A discriminant function analysis identified eight statistically significant variables which differentiated adolescents placed in mental health or juvenile justice systems. In order of decreasing importance they are: ethnicity, gender, depression, previous mental health history, productivity, drug use, parental marital history, and parental…

  19. FUZZY LOGIC BASED INTELLIGENT CONTROL OF A VARIABLE SPEED CAGE MACHINE WIND GENERATION SYSTEM

    EPA Science Inventory

    The report gives results of a demonstration of the successful application of fuzzy logic to enhance the performance and control of a variable-speed wind generation system. A squirrel cage induction generator feeds the power to either a double-sided pulse-width modulation converte...

  20. Identification of linear discrete time systems using the instrumental variable method

    Microsoft Academic Search

    Kwan Wong; E. Polak

    1967-01-01

    This paper explores the possibility of using the instrumental variable method to estimate the parameters of linear time-invariant discrete-time systems. The existence of optimal estimates is established, methods for their approximate computation are given, and an on-line identification scheme based on recursive computation is proposed. Experimental results are included.

  1. An approach for the compensation of the background variability in fire detection systems

    Microsoft Academic Search

    M. F. Ugarte; R. I. Zequeira; F. López

    2001-01-01

    Background (BG) variability is an important issue in fire detection. Due to atmospheric situations in general a high correlation can be assumed between the BG infrared radiation for spatially near zones. This correlation can be even greater if similar forest and soil-surface conditions exist in these zones. In this paper we present an approach for fire detection in ground systems.

  2. Variable mode bi-directional and uni-directional computer communication system

    DOEpatents

    Cornett, Frank N.; Jenkins, Philip N.; Bowman, Terrance L.; Placek, Joseph M.; Thorson, Gregory M.

    2004-12-14

    A variable communication systems comprising a plurality of transceivers and a control circuit connected to the transceivers to configure the transceivers to operate in a bi-directional mode and a uni-directional mode at different times using different transfer methods to transfer data.

  3. Internal Variability of the Troposphere-Stratosphere Coupled System Simulated in a Simple Global Circulation Model

    Microsoft Academic Search

    Masakazu Taguchi; Takashi Yamaga; Shigeo Yoden

    2001-01-01

    Internal variability of a troposphere-stratosphere coupled system is investigated in a series of numerical experiments with a simple global circulation model under a perpetual winter condition. In order to examine the relative importance of forced planetary waves in the interaction with the zonal mean zonal flow and baroclinic disturbances, amplitude of a sinusoidal surface topography of zonal wavenumber 1 or

  4. AS TFT semiactive controller for base isolated buildings with variable stiffness isolation systems

    Microsoft Academic Search

    Sriram Narasimhana

    An ew short time Fourier transformation (STFT) control algorithm is developed for reducing the response of base isolated buildings with variable stiffness isolation systems in near fault earthquakes. The central idea of STFT is to break up the signal into small time segments and Fourier analyze each time segment to ascertain the frequencies that exist in it. For each different

  5. A STFT semiactive controller for base isolated buildings with variable stiffness isolation systems

    Microsoft Academic Search

    Sriram Narasimhan; Satish Nagarajaiah

    2005-01-01

    A new short time Fourier transformation (STFT) control algorithm is developed for reducing the response of base isolated buildings with variable stiffness isolation systems in near fault earthquakes. The central idea of STFT is to break up the signal into small time segments and Fourier analyze each time segment to ascertain the frequencies that exist in it. For each different

  6. Technical and economical considerations in the application of variable-speed drives with electric motor systems

    Microsoft Academic Search

    Aníbal T. de Almeida; Fernando J. T. E. Ferreira; D. Both

    2005-01-01

    In the European Union (EU), variable-speed drives (VSDs) were identified as the motor systems technology having the most significant electricity savings potential. In the EU, the identified economic electricity savings potential with the application of VSDs, by the year 2015, in industrial and tertiary sectors, are 39 and 8 TWh\\/year, respectively. However, only a small percentage of this potential is

  7. Programmable State-Variable Filter Design For a Feedback Systems Web-Based Laboratory

    E-print Network

    Dawson, Joel

    Programmable State-Variable Filter Design For a Feedback Systems Web-Based Laboratory by Rayal.2.2 PHP Web Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 4 Measurements 18 5 Future Work 20 6 Conclusion 21 A PIC16F628 Assembly Code 22 B PHP Code 25 2 #12;1 Introduction

  8. Multi-zone cold storage variable air volume air conditioning system

    Microsoft Academic Search

    Meckler

    1988-01-01

    A multi-zone thermal energy storage variable air volume heating and cooling air conditioning system for capacity effective averaging in the selection of a multiplicity of continuously operable refrigeration cooling units that may vary in capacity and each operable at its optimum capacity and assigned to a separate zone space is described including: a zone space heating and cooling units and

  9. SIMPLIFIED MODEL OF PRESSURE REGULATED, VARIABLE DISPLACEMENT PUMPS FOR THE SIZING OF COMPLEX HYDRAULIC SYSTEMS

    Microsoft Academic Search

    Pr Jean; Charles MARE

    In this communication, a simplified object-oriented model of pressure regulated, variable displacement pumps is proposed in order to be inserted in the components library for the sizing of complex hydraulic systems. The model is derived from the pump supplier data in order to reproduce both static and dynamic hydraulic characteristics and the pressure ripple at the pump outlet orifice. Analytical

  10. Precision zonal management systems for resilient cereal yields and ecosystem services under variable climates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increasing climatic variability is likely to increase production risks in cereal production and to exacerbate harmful biogeochemical impacts of these systems. Reduced tillage and continuous living cover (e.g., cover crops) may help manage these effects, but both impose other costs and risks. Conside...

  11. Depth of Field Adaptation for Observation of Microscopic Objects by Using Variable Annular Aperture System

    Microsoft Academic Search

    Deokhwa Hong; Hyungsuck Cho

    2010-01-01

    High magnification optical systems such as microscopes usually suffer from limited depth-of-field (DOF) problem. This hinders efficient observation of microscopic objects and prevents vision based approaches from being applied to automatic micromanipulation tasks. A DOF extension method using variable annular pupil was proposed by the authors' previous publication, and a tradeoff between the depth extension range and image quality was

  12. Development and Testing of a Variable Conductance Thermal Acquisition, Transport, and Switching System

    NASA Technical Reports Server (NTRS)

    Bugby, David C.; Farmer, Jeffery T.; Stouffer, Charles J.

    2013-01-01

    This paper describes the development and testing of a scalable thermal management architecture for instruments, subsystems, or systems that must operate in severe space environments with wide variations in sink temperature. The architecture involves a serial linkage of one or more hot-side variable conductance heat pipes (VCHPs) to one or more cold-side loop heat pipes (LHPs). The VCHPs provide wide area heat acquisition, limited distance thermal transport, modest against gravity pumping, concentrated LHP startup heating, and high switching ratio variable conductance operation. The LHPs provide localized heat acquisition, long distance thermal transport, significant against gravity pumping, and high switching ratio variable conductance operation. The single-VCHP, single-LHP system described herein was developed to maintain thermal control of a small robotic lunar lander throughout the lunar day-night thermal cycle. It is also applicable to other variable heat rejection space missions in severe environments. Operationally, despite a 60-70% gas blocked VCHP condenser during ON testing, the system was still able to provide 2-4 W/K ON conductance, 0.01 W/K OFF conductance, and an end-to-end switching ratio of 200-400. The paper provides a detailed analysis of VCHP condenser performance, which quantified the gas blockage situation. Future multi-VCHP/multi-LHP thermal management system concepts that provide power/transport length scalability are also discussed.

  13. PREPROCESSING, VARIABLE SELECTION AND CLASSIFICATION RULES IN THE APPLICATION OF SIMCA PATTERN RECOGNITION TO MASS SPECTRAL DATA

    EPA Science Inventory

    In a recent report a strategy was proposed for the classification and identification of toxic organic compounds observed in ambient air from mass spectra using computational pattern recognition based on SlMCA principal components modeling of the autocorrelation transformed mass s...

  14. Improving Performance of Power Systems with Large-scale Variable Generation Additions

    SciTech Connect

    Makarov, Yuri V.; Etingov, Pavel V.; Samaan, Nader A.; Lu, Ning; Ma, Jian; Subbarao, Krishnappa; Du, Pengwei; Kannberg, Landis D.

    2012-07-22

    A power system with large-scale renewable resources, like wind and solar generation, creates significant challenges to system control performance and reliability characteristics because of intermittency and uncertainties associated with variable generation. It is important to quantify these uncertainties, and then incorporate this information into decision-making processes and power system operations. This paper presents three approaches to evaluate the flexibility needed from conventional generators and other resources in the presence of variable generation as well as provide this flexibility from a non-traditional resource – wide area energy storage system. These approaches provide operators with much-needed information on the likelihood and magnitude of ramping and capacity problems, and the ability to dispatch available resources in response to such problems.

  15. Orbital periods of cataclysmic variables identified by the SDSS. IX. NTT photometry of eight eclipsing and three magnetic systems

    NASA Astrophysics Data System (ADS)

    Southworth, J.; Tappert, C.; Gänsicke, B. T.; Copperwheat, C. M.

    2015-01-01

    We report the discovery of eclipses and the first orbital period measurements for four cataclysmic variables, plus the first orbital period measurements for one known eclipsing and two magnetic systems. SDSS J093537.46+161950.8 exhibits 1 mag deep eclipses with a period of 92.245 min. SDSS J105754.25+275947.5 has short and deep eclipses and an orbital period of 90.44 min. Its light curve has no trace of a bright spot and its spectrum is dominated by the white dwarf component, suggesting a low mass accretion rate and a very low-mass and cool secondary star. CSS J132536+210037 shows 1 mag deep eclipses each separated by 89.821 min. SDSS J075653.11+085831.8 shows 2 mag deep eclipses on a period of 197.154 min. CSS J112634-100210 is an eclipsing dwarf nova identified in the Catalina Real Time Transit Survey, for which we measure a period of 111.523 min. SDSS J092122.84+203857.1 is a magnetic system with an orbital period of 84.240 min; its light curve is a textbook example of cyclotron beaming. A period of 158.72 min is found for the faint magnetic system SDSS J132411.57+032050.4, whose orbital light variations are reminiscent of AM Her. Improved orbital period measurements are also given for three known SDSS cataclysmic variables. We investigate the orbital period distribution and fraction of eclipsing systems within the SDSS sample and for all cataclysmic variables with a known orbital period, with the finding that the fraction of known CVs which are eclipsing is not strongly dependent on the orbital period. The reduced observational data presented in this work are available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/573/A61 and at http://www.astro.keele.ac.uk/~jkt/

  16. Integrating GIS and GPS into a spatially-variable-rate herbicide application system

    Microsoft Academic Search

    Khalid Ali Al-Gaadi

    1998-01-01

    A spatially variable rate herbicide application system was developed and a site-specific evaluation of its field performance and accuracy was conducted. The system was capable of automatically changing on-the-go the application rate of active ingredients (AI) to meet the requirements of current sprayer field location. A 4.2 ha field was sampled on an 18.3 m grid for soil texture and

  17. Mean Structure and Interannual Variability of the Slopewater System South of Newfoundland

    Microsoft Academic Search

    Robert S. Pickart; Theresa K. McKee; Daniel J. Torres; Stephanie A. Harrington

    1999-01-01

    Two sets of repeat hydrographic sections, centered at 558W and 508W, are used to study the mean features and long-term variability of the slopewater system south of Newfoundland, inshore of the Gulf Stream. The upper-layer flow is considered first, consisting of the westward-flowing Labrador Current at the shelfbreak (input into the slopewater system) and the eastward-flowing slopewater current over midslope

  18. Optical system for variable resizing of round flat-top distributions

    Microsoft Academic Search

    George Nemes; John A. Hoffnagle

    2006-01-01

    An optical system is described which is capable of variable resizing of a round flat-top light distribution of a highly coherent and collimated laser beam at a certain, fixed working distance. It contains cylindrical and spherical optics. First-order optics is used to analyze the system, and the second-order moments method is used to describe the beam properties. The analysis indicates

  19. Investigation on multi-variable decoupled temperature control system for enamelling machine with heated air circulation

    SciTech Connect

    Li, Yang; Qin, Le; Zou, Shipeng; Long, Shijun [School of Information Engineering, Guangdong University of Technology, Guangzhou, 510006 (China)

    2014-04-11

    A lots of problems may occur frequently when controlling the temperature of the enamelling machine oven in the real industrial process, such as multi-variable coupled problem. an experimental rig with triple inputs and triple outputs was devised and a simulation modeling was established accordingly in this study,. the temperature control system based on the feedforward compensation algorithm was proposed. Experimental results have shown that the system is of high efficiency, good stability and promising application.

  20. Power-profile Driven Variable Voltage Sealing for Heterogeneous Distributed Real-time Embedded Systems

    Microsoft Academic Search

    Jiong Luo; Niraj K. Jha

    2003-01-01

    Presents a power-aware real-time distributed embedded system scheduling algorithm. It tries to satisfy the hard real-time constraints and precedence relationships of the tasks in the distributed embedded system specification. At the same time, it performs variable voltage scaling by addressing variations in power consumption of different tasks and characteristics of different voltage-scalable processing elements (PEs) in an effective and efficient

  1. Power optimization of real-time embedded systems on variable speed processors

    Microsoft Academic Search

    Youngsoo Shin; Kiyoung Chois; Takayasu Sakurait

    2000-01-01

    Power efficient design of real-time embedded systems based on programmable processors becomes more important as system functionality is increasingly realized through software. This paper presents a power optimization method for real-time embedded applications on a variable speed processor. The method combines off-line and on-line components. The off-line component determines the lowest possible maximum processor speed while guaranteeing deadlines of all

  2. Source-related variables for the description of the oceanic carbon system

    NASA Astrophysics Data System (ADS)

    Walin, G.; Hieronymus, J.; Nycander, J.

    2014-09-01

    oceanic carbon system is commonly described in terms of the two state variables total carbon, DIC, and alkalinity, Alk. Here we suggest the use of alternative source adapted state variables, Acidic Carbon, AC and Basic Carbon, BC, defined by and related to (DIC, Alk) with a simple linear transformation. (AC, BC) can be interpreted as representing respectively the supply to the system of carbon dioxide and dissolved carbonate, keeping in mind that supply of hydrogen ions acts to transform from basic carbon to acidic carbon. Accordingly these variables tell us how much carbon dioxide or dissolved carbonate we actually have in the water, despite the fact that the major part of the carbon resides in bicarbonate ions. We claim that using these source-related variables as a compliment to the traditional variables, offers a number of advantages in the formulation of continuity equations, as well as in the interpretation of observations and modeling results. The traditional definition of alkalinity is related to a measuring procedure rather than to the supply of material to the system. Here we demonstrate that alkalinity, though defined in the traditional way, may be interpreted in terms of sources and sinks acting on the system. In the case of ocean water this amounts to twice the supply of dissolved carbonate minus the net supply of free hydrogen ions. We argue that this interpretation is a useful complement to the traditional definition. Every process that affects the state of the carbon system may be quantified in terms of supply of carbon dioxide, Fa, carbonate ions, Fb, or hydrogen ions, E.

  3. Low-frequency variability in the arctic atmosphere, sea ice, and upper-ocean climate system

    SciTech Connect

    Bitz, C.M.; Battisti, D.S. [Univ. of Washington, Seattle, WA (United States)] [Univ. of Washington, Seattle, WA (United States); Moritz, R.E. [Univ. of Washington, Seattle, WA (United States)] [Univ. of Washington, Seattle, WA (United States); Beesley, J.A. [Univ. of Washington, Seattle, WA (United States)] [Univ. of Washington, Seattle, WA (United States)

    1996-02-01

    The low-frequency natural variability of the arctic climate system is modeled using a single-column, energy balance model of the atmosphere, sea ice, and upper-ocean system. Variability in the system is induced by forcing with realistic, random perturbations in the atmospheric energy transport and cloudiness. The model predicts that the volume of perennial sea ice varies predominantly on decadal timescales, while other arctic climate variables vary mostly on intraannual and interannual timescales. The variance of the simulated sea ice volume is most sensitive to perturbations of the atmospheric forcing in late spring, at the onset of melt. The variance of the simulated sea ice volume is most sensitive to perturbations of the atmospheric forcing in the late spring, at the onset of melt. The variance of sea ice volume increases with the mean sea ice thickness and with the number of layers resolved in the sea ice model. This suggests that much of the simulated variance develops when the surface temperature decouples from the sea ice interior during the late spring, when melting snow abruptly exposes the sea ice surface and decreases the surface albedo. The minimum model requirements to simulate the natural variability in the arctic climate are identified. The implications of the low-frequency, natural variability in sea ice volume for detecting a climate change are discussed. Finally, calculations suggest that the variability in the thermodynamic forcing of the polar cap could lead to a freshening in North Atlantic that is comparable to the freshening associated with the Great Salinity Anomaly. 28 refs., 14 figs., 5 tabs.

  4. A model following variable stability system for the NASA ARC X-14B.

    NASA Technical Reports Server (NTRS)

    Gallagher, J. T.; Saworotnow, I.; Seemann, R.; Gossett, T. D.

    1972-01-01

    A description of the basic design concept, hardware design, and flight evaluation of a Variable Stability System (VSS) installed on the NASA ARC X-14B is presented. The NASA ARC X-14B is a twin-engine, single-seated VTOL aircraft. The VSS is unique in that it employs a general purpose airborne digital computer as an integral part of the hybrid model following flight control system. The system design, analysis and testing phases are discussed in the paper from the application of optimal control techniques in the preliminary design of the system, through the flight demonstration of the VSS hardware.

  5. A variable speed wind energy conversion scheme for connection to weak AC systems

    SciTech Connect

    Neris, A.S.; Vovos, N.A.; Giannakopoulos, G.B. [Univ. of Patras, Rion (Greece). Dept. of Electrical and Computer Engineering] [Univ. of Patras, Rion (Greece). Dept. of Electrical and Computer Engineering

    1999-03-01

    A three level control system for a variable speed wind energy conversion scheme (VSWECS) supplying a weak AC system is presented. The objective of the control strategy is to maximize energy capture and simultaneously to support the voltage of the bus where the VSWECS is connected. Using an insulated gate bipolar transistors (IGBT) inverter both control of active and reactive power supplied to the grid and reduction of harmonic distortion can be achieved. The response of the proposed scheme has been tested and evaluated in a test system using a developed computer program simulating in detail the system operation.

  6. Fluctuations in the motions of mass and of patterns in one-dimensional driven diffusive systems

    Microsoft Academic Search

    H. van Beijeren

    1991-01-01

    The stochastic spreading of mass fluctuations in systems described by a fluctuating Burgers equation increases ast2\\/3 with time. As a consequence the stochastic motion of a mass front, a point through which no excess mass current is flowing, is shown to increase ast1\\/3. The same is true for the stochastic displacement of mass points and shock fronts with respect to

  7. Modeling of Variable Coefficient Roesser Model for Systems Described by Second-Order Partial Differential Equation

    Microsoft Academic Search

    C. W. Chen; J. S. H. Tsai; L. S. Shieh

    2003-01-01

    This paper addresses how a variable coefficient, two-dimensional (2D)\\u000a multiple-input, multiple-output system described by second-order partial differential\\u000a equations (PDEs) can be converted to a discrete variable coefficient Roesser model (RM).\\u000a The following important question for its practical application is addressed: How does the\\u000a choice of the finite difference operators for each differential operator and the respective\\u000a integral intervals determine whether

  8. Modeling the seasonal variability of a coupled Arctic ice-ocean system

    NASA Technical Reports Server (NTRS)

    Hakkinen, Sirpa; Mellor, George L.

    1992-01-01

    The seasonal variability of the ice-ocean system in the Arctic Basin and the Norwegian, Greenland, and Barents Seas was modeled using a three-dimensional coupled ice-ocean model developed at Princeton University. The snow-ice model uses a three-level thermodynamic scheme similar to Semtner's (1976), but is extended to include the effect of leads. It is shown that simulations using the climatological monthly forcing fields produce a realistic seasonal variability of the ice cover. The ice thickness had a considerable sensitivity to the choice of the long-wave back radiation scheme, but these effects can be reduced through dynamical factors.

  9. Identification of a Wide, Low-Mass Multiple System Containing the Brown Dwarf 2MASS J0850359+105716

    NASA Astrophysics Data System (ADS)

    Faherty, Jacqueline K.; Burgasser, Adam J.; Bochanski, John J.; Looper, Dagny L.; West, Andrew A.; van der Bliek, Nicole S.

    2011-03-01

    We report our discovery of NLTT 20346 as an M5+M6 companion system to the tight binary (or triple) L dwarf 2MASS J0850359+105716. This nearby (~31 pc), widely separated (~7700 AU) quadruple system was identified through a cross-match of proper motion catalogs. Follow-up imaging and spectroscopy of NLTT 20346 revealed it to be a magnetically active M5+M6 binary with components separated by ~2'' (50-80 AU). Optical spectroscopy of the components shows only moderate H? emission corresponding to a statistical age of ~5-7 Gyr for both M dwarfs. However, NLTT 20346 is associated with the XMM-Newton source J085018.9+105644, and based on X-ray activity the age of NLTT 20346 is between 250 and 450 Myr. Strong Li absorption in the optical spectrum of 2MASS J0850+1057 indicates an upper age limit of 0.8-1.5 Gyr, favoring the younger age for the primary. Using evolutionary models in combination with an adopted system age of 0.25-1.5 Gyr indicates a total mass for 2MASS J0850+1057 of 0.07 ± 0.02 M sun, if it is a binary. NLTT 20346/2MASS J0850+1057 joins a growing list of hierarchical systems containing brown dwarf binaries and is among the lowest binding energy associations found in the field. Formation simulations via gravitational fragmentation of massive extended disks have successfully produced a specific analog to this system. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

  10. IDENTIFICATION OF A WIDE, LOW-MASS MULTIPLE SYSTEM CONTAINING THE BROWN DWARF 2MASS J0850359+105716

    SciTech Connect

    Faherty, Jacqueline K. [Department of Astrophysics, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10034 (United States); Burgasser, Adam J. [Center of Astrophysics and Space Sciences, Department of Physics, University of California, San Diego, CA 92093 (United States); Bochanski, John J. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Looper, Dagny L. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); West, Andrew A. [Department of Astronomy, Boston University, 725 Commonwealth Avenue Boston, MA 02215 (United States); Van der Bliek, Nicole S., E-mail: jfaherty@amnh.org [CTIO/National Optical Astronomy Observatory, Casilla 603, La Serena (Chile)

    2011-03-15

    We report our discovery of NLTT 20346 as an M5+M6 companion system to the tight binary (or triple) L dwarf 2MASS J0850359+105716. This nearby ({approx}31 pc), widely separated ({approx}7700 AU) quadruple system was identified through a cross-match of proper motion catalogs. Follow-up imaging and spectroscopy of NLTT 20346 revealed it to be a magnetically active M5+M6 binary with components separated by {approx}2'' (50-80 AU). Optical spectroscopy of the components shows only moderate H{alpha} emission corresponding to a statistical age of {approx}5-7 Gyr for both M dwarfs. However, NLTT 20346 is associated with the XMM-Newton source J085018.9+105644, and based on X-ray activity the age of NLTT 20346 is between 250 and 450 Myr. Strong Li absorption in the optical spectrum of 2MASS J0850+1057 indicates an upper age limit of 0.8-1.5 Gyr, favoring the younger age for the primary. Using evolutionary models in combination with an adopted system age of 0.25-1.5 Gyr indicates a total mass for 2MASS J0850+1057 of 0.07 {+-} 0.02 M{sub sun}, if it is a binary. NLTT 20346/2MASS J0850+1057 joins a growing list of hierarchical systems containing brown dwarf binaries and is among the lowest binding energy associations found in the field. Formation simulations via gravitational fragmentation of massive extended disks have successfully produced a specific analog to this system.

  11. Reresentation of the interannual variability of equatorial Pacific air-sea CO2 flux in the lasted earth system models

    NASA Astrophysics Data System (ADS)

    Dong, Fang; Li, Yangchun; Wang, Bin; Huang, Wenyu; Shi, Yanyan

    2015-04-01

    We analyze the interannual variability of the air-sea CO2 flux over the equatorial Pacific in the latest earth system models (ESMs; we choose 16 models with enough outputs of variables closely associated with the air-sea CO2 flux variation for analyzing). Our results show that, about half of the models analyzed here have weaker interannual variability of the air-sea CO2 flux over the equatorial Pacific compared with the previous observational results, although the 16 models are capable to illustrate the spatial distribution character of the air-sea CO2 flux over the equatorial Pacific. For the possible reason for the weak interannual variation of the air-sea CO2 flux over the equatorial Pacific in the models, we first examine the ENSO mode of the equatorial Pacific air-sea CO2 flux, with the considering of that the equatorial Pacific air-sea CO2 flux variation is dominated by El Niño events. Then we briefly analyze the variables which jointly influence the air-sea CO2 flux interannual variability (such as, sea surface temperature (SST) , dissolved inorganic carbon (DIC) in the surface ocean, upward ocean mass transport (WMO), and net primary productivity of carbon by phytoplankton (NPP)). Nine of the 16 models are capable to represent the ENSO mode of the air-sea CO2 flux over the equatorial Pacific, the other seven of them are incapable to represent this important character. Incapacity of representing the ENSO mode of the air-sea CO2 flux in some models implies the limitation in depicting the response of air-sea CO2 flux to the El Niño events over the equatorial Pacific, which contributes to weak interannual variability of air-sea CO2 flux to some extent. The variations of DIC, NPP and WMO have large divergences in the 16 models over the central-eastern equatorial Pacific. Improvement of the depiction of physical and biological fields are important for accurate interannual variation of the equatorial air-sea CO2 flux.

  12. Computer simulation of mass transport in a driven diffusive system

    Microsoft Academic Search

    Jørgen Vitting Andersen; Ole G Mouritsen

    1990-01-01

    Monte Carlo computer-simulation techniques are applied to study the mass-density profile and the mass flux in a two-dimensional lattice-gas model driven by a chemical-potential gradient. The collective diffusion constant is calculated and shown to have a dramatic temperature dependence with an anomalous depression at the non-equilibrium phase transition of the model. For large values of the chemical potential gradient the

  13. Electronic drive and acquisition system for mass spectrometry

    NASA Technical Reports Server (NTRS)

    Schaefer, Rembrandt Thomas (Inventor); Mojarradi, Mohammad (Inventor); Chutjian, Ara (Inventor); Darrach, Murray R. (Inventor); MacAskill, John (Inventor); Tran, Tuan (Inventor); Burke, Gary R. (Inventor); Madzunkov, Stojan M. (Inventor); Blaes, Brent R. (Inventor); Thomas, John L. (Inventor)

    2010-01-01

    The present invention discloses a mixed signal RF drive electronics board that offers small, low power, reliable, and customizable method for driving and generating mass spectra from a mass spectrometer, and for control of other functions such as electron ionizer, ion focusing, single-ion detection, multi-channel data accumulation and, if desired, front-end interfaces such as pumps, valves, heaters, and columns.

  14. Structural analysis of TPX Cold-Mass Support System

    Microsoft Academic Search

    1992-01-01

    The Tokamak Physics Experiment (TPX) will be located at the Princeton Plasma Physics Laboratory, Princeton, New Jersey. The Tokamak uses superconducting magnets that operate at 4K. The magnets and some supporting structure are contained within a cryostat. These components are collectively referred to as the cold-mass. The bottom of the cold-mass rests on a support structure that must provide resistance

  15. Seasonal and spatial variability of the OM/OC mass ratios and high regional correlation between oxalic acid and zinc in Chinese urban organic aerosols

    NASA Astrophysics Data System (ADS)

    Xing, L.; Fu, T.-M.; Cao, J. J.; Lee, S. C.; Wang, G. H.; Ho, K. F.; Cheng, M.-C.; You, C.-F.; Wang, T. J.

    2013-04-01

    We calculated the organic matter to organic carbon mass ratios (OM/OC mass ratios) in PM2.5 collected from 14 Chinese cities during summer and winter of 2003 and analyzed the causes for their seasonal and spatial variability. The OM/OC mass ratios were calculated two ways. Using a mass balance method, the calculated OM/OC mass ratios averaged 1.92 ± 0.39 year-round, with no significant seasonal or spatial variation. The second calculation was based on chemical species analyses of the organic compounds extracted from the PM2.5 samples using dichloromethane/methanol and water. The calculated OM/OC mass ratio in summer was relatively high (1.75 ± 0.13) and spatially-invariant due to vigorous photochemistry and secondary organic aerosol (OA) production throughout the country. The calculated OM/OC mass ratio in winter (1.59 ± 0.18) was significantly lower than that in summer, with lower values in northern cities (1.51 ± 0.07) than in southern cities (1.65 ± 0.15). This likely reflects the wider usage of coal for heating purposes in northern China in winter, in contrast to the larger contributions from biofuel and biomass burning in southern China in winter. On average, organic matter constituted 36% and 34% of Chinese urban PM2.5 mass in summer and winter, respectively. We report, for the first time, a high regional correlation between Zn and oxalic acid in Chinese urban aerosols in summer. This is consistent with the formation of stable Zn oxalate complex in the aerosol phase previously proposed by Furukawa and Takahashi (2011). We found that many other dicarboxylic acids were also highly correlated with Zn in the summer Chinese urban aerosol samples, suggesting that they may also form stable organic complexes with Zn. Such formation may have profound implications for the atmospheric abundance and hygroscopic properties of aerosol dicarboxylic acids.

  16. A study of the mass loss rates of symbiotic star systems

    NASA Astrophysics Data System (ADS)

    Korreck, K. E.; Kellogg, E.; Sokoloski, J. L.

    2007-08-01

    The amount of mass loss in symbiotic systems is investigated, specifically mass loss via the formation of jets in R Aquarii (R Aqr). The jets in R Aqr have been observed in the X-ray by Chandra over a four year time period. The jet changes on times scales of a year and new outflows have been observed. Understanding the amount of mass and the frequency of ejection further constrain the ability of the white dwarf in the system to accrete enough mass to become a Type 1a supernova progenitor. The details of multi-wavelength studies, such as speed, density and spatial extent of the jets will be discussed in order to understand the mass balance in the binary system. We examine other symbiotic systems to determine trends in mass loss in this class of objects.

  17. A study of the mass loss rates of symbiotic star systems

    E-print Network

    Korreck, K E; Sokoloski, J L

    2006-01-01

    The amount of mass loss in symbiotic systems is investigated, specifically mass loss via the formation of jets in R Aquarii (R Aqr). The jets in R Aqr have been observed in the X-ray by Chandra over a four year time period. The jet changes on times scales of a year and new outflows have been observed. Understanding the amount of mass and the frequency of ejection further constrain the ability of the white dwarf in the system to accrete enough mass to become a Type 1a supernova progenitor. The details of multi-wavelength studies, such as speed, density and spatial extent of the jets will be discussed in order to understand the mass balance in the binary system. We examine other symbiotic systems to determine trends in mass loss in this class of objects.

  18. A study of the mass loss rates of symbiotic star systems

    E-print Network

    K. E. Korreck; E. Kellogg; J. L. Sokoloski

    2006-11-13

    The amount of mass loss in symbiotic systems is investigated, specifically mass loss via the formation of jets in R Aquarii (R Aqr). The jets in R Aqr have been observed in the X-ray by Chandra over a four year time period. The jet changes on times scales of a year and new outflows have been observed. Understanding the amount of mass and the frequency of ejection further constrain the ability of the white dwarf in the system to accrete enough mass to become a Type 1a supernova progenitor. The details of multi-wavelength studies, such as speed, density and spatial extent of the jets will be discussed in order to understand the mass balance in the binary system. We examine other symbiotic systems to determine trends in mass loss in this class of objects.

  19. Clinical diagnosis and typing of systemic amyloidosis in subcutaneous fat aspirates by mass spectrometry-based proteomics

    PubMed Central

    Vrana, Julie A.; Theis, Jason D.; Dasari, Surendra; Mereuta, Oana M.; Dispenzieri, Angela; Zeldenrust, Steven R.; Gertz, Morie A.; Kurtin, Paul J.; Grogg, Karen L.; Dogan, Ahmet

    2014-01-01

    Examination of abdominal subcutaneous fat aspirates is a practical, sensitive and specific method for the diagnosis of systemic amyloidosis. Here we describe the development and implementation of a clinical assay using mass spectrometry-based proteomics to type amyloidosis in subcutaneous fat aspirates. First, we validated the assay comparing amyloid-positive (n=43) and -negative (n=26) subcutaneous fat aspirates. The assay classified amyloidosis with 88% sensitivity and 96% specificity. We then implemented the assay as a clinical test, and analyzed 366 amyloid-positive subcutaneous fat aspirates in a 4-year period as part of routine clinical care. The assay had a sensitivity of 90%, and diverse amyloid types, including immunoglobulin light chain (74%), transthyretin (13%), serum amyloid A (%1), gelsolin (1%), and lysozyme (1%), were identified. Using bioinformatics, we identified a universal amyloid proteome signature, which has high sensitivity and specificity for amyloidosis similar to that of Congo red staining. We curated proteome databases which included variant proteins associated with systemic amyloidosis, and identified clonotypic immunoglobulin variable gene usage in immunoglobulin light chain amyloidosis, and the variant peptides in hereditary transthyretin amyloidosis. In conclusion, mass spectrometry-based proteomic analysis of subcutaneous fat aspirates offers a powerful tool for the diagnosis and typing of systemic amyloidosis. The assay reveals the underlying pathogenesis by identifying variable gene usage in immunoglobulin light chains and the variant peptides in hereditary amyloidosis. PMID:24747948

  20. Sixth Goddard Conference on Mass Storage Systems and Technologies Held in Cooperation with the Fifteenth IEEE Symposium on Mass Storage Systems

    NASA Technical Reports Server (NTRS)

    Kobler, Benjamin (Editor); Hariharan, P. C. (Editor)

    1998-01-01

    This document contains copies of those technical papers received in time for publication prior to the Sixth Goddard Conference on Mass Storage Systems and Technologies which is being held in cooperation with the Fifteenth IEEE Symposium on Mass Storage Systems at the University of Maryland-University College Inn and Conference Center March 23-26, 1998. As one of an ongoing series, this Conference continues to provide a forum for discussion of issues relevant to the management of large volumes of data. The Conference encourages all interested organizations to discuss long term mass storage requirements and experiences in fielding solutions. Emphasis is on current and future practical solutions addressing issues in data management, storage systems and media, data acquisition, long term retention of data, and data distribution. This year's discussion topics include architecture, tape optimization, new technology, performance, standards, site reports, vendor solutions. Tutorials will be available on shared file systems, file system backups, data mining, and the dynamics of obsolescence.

  1. Development of a variable-temperature ion mobility/ time-of-flight mass spectrometer for separation of electronic isomers 

    E-print Network

    Verbeck, Guido Fridolin

    2005-08-29

    The construction of a liquid nitrogen-cooled ion mobility spectrometer coupled with time-of-flight mass spectrometry was implemented to demonstrate the ability to discriminate between electronic isomers. Ion mobility allows ...

  2. Variable Sweep Transition Flight Experiment (VSTFE): Unified Stability System (USS). Description and Users' Manual

    NASA Technical Reports Server (NTRS)

    Rozendaal, Rodger A.; Behbehani, Roxanna

    1990-01-01

    NASA initiated the Variable Sweep Transition Flight Experiment (VSTFE) to establish a boundary layer transition database for laminar flow wing design. For this experiment, full-span upper surface gloves were fitted to a variable sweep F-14 aircraft. The development of an improved laminar boundary layer stability analysis system called the Unified Stability System (USS) is documented and results of its use on the VSTFE flight data are shown. The USS consists of eight computer codes. The theoretical background of the system is described, as is the input, output, and usage hints. The USS is capable of analyzing boundary layer stability over a wide range of disturbance frequencies and orientations, making it possible to use different philosophies in calculating the growth of disturbances on sweptwings.

  3. Analytical investigation of the pericyclic variable-speed transmission system for helicopter main-gearbox

    NASA Astrophysics Data System (ADS)

    Saribay, Zihni Burcay

    In the recent years, there has been significant interest in the new developments and improvements of the rotorcraft transmission systems. The main goal of the rotorcraft transmission research is the reduction of overall gear train weight while maintaining the efficiency and reliability. The Pericyclic Variable-Speed Transmission (PVT) System is one of the potential candidates of the future rotorcraft drive trains to achieve these goals. Hence, this thesis explores the feasibility of the Pericyclic Variable Speed Transmission (PVT) for rotorcraft transmissions. The contributions of this research are grouped in two main categories. These two categories are in the component level and in the system level. These contributions are originated from the analysis of the Pericyclic Variable Speed (PVT) System. In the component level, a new concept of face-gear meshing is presented first time in the gear research field. The meshing of a face-gear with another face-gear is presented at high shaft angles as an alternative to bevel gears. The conjugacy of this new face-gear meshing concept is formulated and demonstrated. The geometry, unloaded mesh kinematics and loaded mesh kinematics of the conjugate meshing face-gear pair is analyzed. The physics behind the meshing face-gear teeth contact is revealed using theory of gearing, differentiable geometry and elastohydrodynamic lubrication theory. The existence of the lubricant film formation between the meshing teeth is demonstrated. The behavior of the sliding friction coefficient is analytically simulated through the meshing cycle. In the system level contributions, the Pericyclic Variable Speed (PVT) Transmission is presented as a new unique innovative gear train mechanism. The speed change capability is analyzed for rotorcraft demands. The power flow behavior is explored for its use in variable speed transmission systems. The established component level contributions are evaluated with the PVT at the system level. The efficiency and load carrying capacity of the PVT face-gears are analyzed at the helicopter torque levels. The dynamic motion of the nutating gear mechanisms is studied to capture the load carrying capacity of the PVT support bearings. A design analysis of the PVT system with 24:1 reduction ratio at 764HP power level is conducted to replace 3 reduction stages of the existing K-MAX intermeshing rotor transmission system. The design and analysis tools established in this research are applied in the design study. The achieved design is compared to the existing K-MAX transmission. Approximately 50% weight reduction and 70% volume reduction are accomplished with the PVT system with less than 1% lower efficiency than existing K-MAX drive train gears.

  4. Estimating Heat and Mass Transfer Processes in Green Roof Systems: Current Modeling Capabilities and Limitations (Presentation)

    SciTech Connect

    Tabares Velasco, P. C.

    2011-04-01

    This presentation discusses estimating heat and mass transfer processes in green roof systems: current modeling capabilities and limitations. Green roofs are 'specialized roofing systems that support vegetation growth on rooftops.'

  5. Neutron star mass through hydrodynamics in obscured sgHMXB systems

    NASA Astrophysics Data System (ADS)

    Manousakis, Antonios

    2013-10-01

    Obscured sgHMXB discovered by INTEGRAL are characterized by slow stellar winds. The gravity of the accreting neutron star has therefore an important impact on the wind accretion flow. The variability of the absorbing column density with orbital phase and the long term X-ray variability can be directly compared to the predictions of hydrodynamical models to constrain the mass of the neutron star, with an accuracy of a few tenth of solar mass, and the dynamics of the accretion flow. We propose to observe an eclipsing absorbed sgHMXB with XMM to probe the accretion flow, to obtain an independent measure of the NS mass and to further test our hydrodynamical model.

  6. Study on SOA-based architecture of product collaborative design system for mass customization

    Microsoft Academic Search

    Zhi-qiang Zhang; Qing-ming Wu; Chao Zhou; Qiang Zhang

    2008-01-01

    An open and extensible framework of mass customization systems is needed for supporting the seamless integration of customization system, CAX tools and legacy systems. The emergence of service-oriented architecture (SOA) has brought about a loosely coupled computing environment that enables flexible integration and reuse of heterogeneous systems. In this paper, an SOA-based architecture of product collaborative design system (PCDS) for

  7. Development of Parametric Mass and Volume Models for an Aerospace SOFC/Gas Turbine Hybrid System

    NASA Technical Reports Server (NTRS)

    Tornabene, Robert; Wang, Xiao-yen; Steffen, Christopher J., Jr.; Freeh, Joshua E.

    2005-01-01

    In aerospace power systems, mass and volume are key considerations to produce a viable design. The utilization of fuel cells is being studied for a commercial aircraft electrical power unit. Based on preliminary analyses, a SOFC/gas turbine system may be a potential solution. This paper describes the parametric mass and volume models that are used to assess an aerospace hybrid system design. The design tool utilizes input from the thermodynamic system model and produces component sizing, performance, and mass estimates. The software is designed such that the thermodynamic model is linked to the mass and volume model to provide immediate feedback during the design process. It allows for automating an optimization process that accounts for mass and volume in its figure of merit. Each component in the system is modeled with a combination of theoretical and empirical approaches. A description of the assumptions and design analyses is presented.

  8. Phase-variable restriction/modification systems are required for Helicobacter pylori colonization

    PubMed Central

    2014-01-01

    Background One mechanism utilized by bacterial pathogens for host adaptation and immune evasion is the generation of phenotypic diversity by the phasevarion that results from the differential expression of a suite of genes regulated by the activity of a phase-variable methyltransferase within a restriction modification (RM) system. Phasevarions are active in Helicobacter pylori, however there have been no studies investigating the significance of phase-variable RM systems on host colonization. Methods Two mutant types incapable of phase variation were constructed; a clean deletion mutant (‘DEL’) and a mutant (‘ON’) where the homopolymeric repeat was replaced with a non-repeat synonymous sequence, resulting in expression of the full-length protein. The resulting mutants were assessed for their colonisation ability in the mouse model. Results Five phase-variable genes encoding either methyltransferases or members of RM systems were found in H. pylori OND79. Our mutants fell into three categories; 1, those with little effect on colonization, 2, those where expression of the full-length protein was detrimental, 3, those where both mutations were detrimental. Conclusions Our results demonstrated that phase-variable methyltransferases are critical to H. pylori colonization, suggesting that genome methylation and generation of epigenetic diversity is important for colonization and pathogenesis. The third category of mutants suggests that differential genome methylation status of H. pylori cell populations, achieved by the phasevarion, is essential for host adaptation. Studies of phase-variable RM mutants falling in the two other categories, not strictly required for colonization, represent a future perspective to investigate the role of phasevarion in persistence of H. pylori. PMID:25349630

  9. A microelectromechanical systems-enabled, miniature triple quadrupole mass spectrometer.

    PubMed

    Wright, Steven; Malcolm, Andrew; Wright, Christopher; O'Prey, Shane; Crichton, Edward; Dash, Neil; Moseley, Richard W; Zaczek, Wojciech; Edwards, Peter; Fussell, Richard J; Syms, Richard R A

    2015-03-17

    Miniaturized mass spectrometers are becoming increasingly capable, enabling the development of many novel field and laboratory applications. However, to date, triple quadrupole tandem mass spectrometers, the workhorses of quantitative analysis, have not been significantly reduced in size. Here, the basis of a field-deployable triple quadrupole is described. The key development is a highly miniaturized ion optical assembly in which a sequence of six microengineered components is employed to generate ions at atmospheric pressure, provide a vacuum interface, effect ion guiding, and perform fragmentation and mass analysis. Despite its small dimensions, the collision cell efficiently fragments precursor ions and yields product ion spectra that are very similar to those recorded using conventional instruments. The miniature triple quadrupole has been used to detect thiabendazole, a common pesticide, in apples at a level of 10 ng/g. PMID:25708099

  10. The water column distribution of carbonate system variables at the ESTOC site from 1995 to 2004

    NASA Astrophysics Data System (ADS)

    González-Dávila, M.; Santana-Casiano, J. M.; Rueda, M. J.; Llinás, O.

    2010-03-01

    The accelerated rate of increase in the atmospheric carbon dioxide (CO2) and the substantial fraction of anthropogenic CO2 emissions absorbed by the oceans are affecting the anthropocenic properties of seawater. Long-term time series are a powerful tool for investigating any change in ocean bio-geochemistry and its effects on the carbon cycle. We have evaluated the ESTOC (European Station for Time series in the Ocean at the Canary islands) observations of measured pH (total scale at 25 °C) and total alkalinity plus computed total dissolved inorganic carbon CO2 concentration (CT) from 1995 to 2004 for surface and deep waters, by following all changes in response to increasing atmospheric carbon dioxide. The experimental values for the partial surface pressure of CO2 from 1995 to 2008 were also taken into consideration. The data were treated to better understand the fundamental processes controlling vertical distributions in the Eastern North Atlantic Ocean and the accumulation of anthropogenic CO2, CANT. CT at constant salinity, NCT, increased at a rate of 1 ?mol kg-1 yr-1 in the first 200 m, linked to an fCO2 increase of 1.7±0.7 ?atm yr-1 in both the atmosphere and the ocean. Consequently, the ESTOC site has also become more acidic, -0.0018±0.0003 units yr-1 over the first 100 m, whereas the carbonate ion concentrations and CaCO3 saturation states have also decreased over time. The rate of change is to be observed over the first 1000 m, where at 300, 600, and 1000 m the NCT increases at a rate of 0.69, 0.61 and 0.48 ?mol kg-1 yr-1, respectively. The vertical distribution of the carbonate system variables are affected by the water mass structure and, to a different extent, controlled by the production/decomposition of organic matter, the formation/dissolution of carbonates, and differences in their respective pre-formed values. At 3000 m, 30% of the inorganic carbon production is related to the dissolution of calcium carbonate, with a total of 35% at the bottom. The total column inventory of anthropogenic CO2 for the decade was 66±3 mol m-2. A model fitting indicated that the column inventory of CANT increased from 61.7 mol m-2 in the year 1994 to 70.2 mol m-2 in 2004. The ESTOC site is presented by way of a reference site to follow CANT changes in the North Atlantic Sub-tropical gyre.

  11. Multiple-Zone Variable Refrigerant Flow System Modeling and Equipment Performance Mapping

    SciTech Connect

    Shen, Bo [ORNL] [ORNL; Rice, C Keith [ORNL] [ORNL

    2012-01-01

    We developed a variable refrigerant flow (VRF) vapor compression system model, which has five indoor units, one outdoor unit and one water heater. The VRF system can run simultaneous space conditioning (cooling or heating) and water heating. The indoor units and outdoor unit use fin-&-tube coil heat exchangers, and the water heater uses a tube-in-tube heat exchanger. The fin-&-tube coil heat exchangers are modeled using a segment-by-segment approach and the tube-in-tube water heater is modeled using a phase-by-phase approach. The compressor used is a variable-speed rotary design. We calibrated our model against a manufacturer s product literature. Based on the vapor compression system model, we investigated the methodology for generating VRF equipment performance maps, which can be used for energy simulations in TRNSYS and EnergyPlus, etc. In the study, the major independent variables for mapping are identified and the deviations between the simplified performance map and the actual equipment system simulation are quantified.

  12. INFLUENCE OF VARIABLE SPEED LIMIT AND DRIVER INFORMATION SYSTEM ON KEY TRAFFIC FLOW PARAMETERS ON A GERMAN AUTOBAHN

    Microsoft Academic Search

    Steven Boice; Robert L. Bertini; Soyoung Ahn; Klaus Bogenberger

    This paper examines key freeway capacity parameters for an 18-kilometer segment of a German autobahn that contains a surveillance system and a variable speed limit and congestion level information system using overhead variable message signs located on gantries. This paper includes an analysis of the relationships between vehicle flow, density, and speed surrounding an active bottleneck. The relationships between key

  13. MASS2, Modular Aquatic Simulation System in Two Dimensions, User Guide and Reference

    SciTech Connect

    Perkins, William A.; Richmond, Marshall C.

    2007-07-01

    The Modular Aquatic Simulation System in Two Dimensions (MASS2) is a two-dimensional, depth-averaged hydrodynamics and transport model. The model simulates time varying distributions of depth-averaged velocities, water surface elevations, and water quality constituents. This manual documents the use of MASS2. It is the second of two reports on MASS2. The first report documents the theory and numerical methods used in MASS2, and is often referred to herein as the Theory Manual. MASS2 is applicable to a wide variety of environmental analyses of rivers and estuaries where vertical variations in the water column are negligible or unimportant.

  14. Energy studies on central and variable refrigerant flow air-conditioning systems

    NASA Astrophysics Data System (ADS)

    Abdullah, H.; Nitamakwuavan, S.; Jalaludin, A. F.

    2012-06-01

    Air-conditioning is a major contributor to energy end-use in commercial buildings. Different types of airconditioning systems are installed in commercial buildings including packaged systems, split units and central systems. With the advancement in control technology and the demand for energy efficient systems, variable refrigerant flow (VRF) air-conditioning system is seen to be a solution to the load-matching problem for airconditioning systems. In a VRF system, the volume or flow rate of the refrigerant is accurately matched to the required cooling load thereby saving energy and providing more accurate control. This study aims to determine the performance of the VRF system used in an actual building by calculating the Coefficient of Performance (COP) of the system. The COP is then compared to the COP of a centralized chilled water system used in the same building. The results showed that the COPs determined for the VRF and central systems are 3.3 and 2.0 respectively. The results also indicated that replacing older central system with a VRF system could lead to an energy savings of up to 39.5%.

  15. Optimized Fan Control In Variable Air Volume HVAC Systems Using Static Pressure Resets: Strategy Selection and Savings Analysis 

    E-print Network

    Kimla, John

    2010-07-14

    particular system, or lack thereof, this tool will facilitate the selection of a SPR control strategy. A field experiment was conducted on a single duct variable air volume system with fixed discharge air temperature and static pressure setpoints. Finally...

  16. Viewing Events in the Center-of-Mass System

    ERIC Educational Resources Information Center

    Ruby, Lawrence

    2010-01-01

    In elementary physics, collisions are usually studied by employing the conservation of momentum, and sometimes also the conservation of kinetic energy. However, in nuclear reactions, changes of mass that complicate the situation often occur. To illustrate the latter, we shall cite two examples of endoergic nuclear reactions, i.e., those for which…

  17. Modelling mass casualty decontamination systems informed by field exercise data.

    PubMed

    Egan, Joseph R; Amlôt, Richard

    2012-10-01

    In the event of a large-scale chemical release in the UK decontamination of ambulant casualties would be undertaken by the Fire and Rescue Service (FRS). The aim of this study was to track the movement of volunteer casualties at two mass decontamination field exercises using passive Radio Frequency Identification tags and detection mats that were placed at pre-defined locations. The exercise data were then used to inform a computer model of the FRS component of the mass decontamination process. Having removed all clothing and having showered, the re-dressing (termed re-robing) of casualties was found to be a bottleneck in the mass decontamination process during both exercises. Computer simulations showed that increasing the capacity of each lane of the re-robe section to accommodate 10 rather than five casualties would be optimal in general, but that a capacity of 15 might be required to accommodate vulnerable individuals. If the duration of the shower was decreased from three minutes to one minute then a per lane re-robe capacity of 20 might be necessary to maximise the throughput of casualties. In conclusion, one practical enhancement to the FRS response may be to provide at least one additional re-robe section per mass decontamination unit. PMID:23202768

  18. Modelling Mass Casualty Decontamination Systems Informed by Field Exercise Data

    PubMed Central

    Egan, Joseph R.; Amlôt, Richard

    2012-01-01

    In the event of a large-scale chemical release in the UK decontamination of ambulant casualties would be undertaken by the Fire and Rescue Service (FRS). The aim of this study was to track the movement of volunteer casualties at two mass decontamination field exercises using passive Radio Frequency Identification tags and detection mats that were placed at pre-defined locations. The exercise data were then used to inform a computer model of the FRS component of the mass decontamination process. Having removed all clothing and having showered, the re-dressing (termed re-robing) of casualties was found to be a bottleneck in the mass decontamination process during both exercises. Computer simulations showed that increasing the capacity of each lane of the re-robe section to accommodate 10 rather than five casualties would be optimal in general, but that a capacity of 15 might be required to accommodate vulnerable individuals. If the duration of the shower was decreased from three minutes to one minute then a per lane re-robe capacity of 20 might be necessary to maximise the throughput of casualties. In conclusion, one practical enhancement to the FRS response may be to provide at least one additional re-robe section per mass decontamination unit. PMID:23202768

  19. NSSDC Conference on Mass Storage Systems and Technologies for Space and Earth Science Applications, volume 1

    NASA Technical Reports Server (NTRS)

    Kobler, Benjamin (editor); Hariharan, P. C. (editor); Blasso, L. G. (editor)

    1992-01-01

    Papers and viewgraphs from the conference are presented. This conference served as a broad forum for the discussion of a number of important issues in the field of mass storage systems. Topics include magnetic disk and tape technologies, optical disks and tape, software storage and file management systems, and experiences with the use of a large, distributed storage system. The technical presentations describe, among other things, integrated mass storage systems that are expected to be available commercially. Also included is a series of presentations from Federal Government organizations and research institutions covering their mass storage requirements for the 1990's.

  20. Quantum Hacking on Continuous-Variable Quantum Key Distribution System using a Wavelength Attack

    E-print Network

    Jing-Zheng Huang; Christian Weedbrook; Zhen-Qiang Yin; Shuang Wang; Hong-Wei Li; Wei Chen; Guang-Can Guo; Zheng-Fu Han

    2013-07-24

    The security proofs of continuous-variable quantum key distribution are based on the assumptions that the eavesdropper can neither act on the local oscillator nor control Bob's beam splitter. These assumptions may be invalid in practice due to potential imperfections in the implementations of such protocols. In this paper, we consider the problem of transmitting the local oscillator in a public channel and propose a wavelength attack which can allow the eavesdropper to control the intensity transmission of Bob's beam splitter by switching the wavelength of the input light. Specifically we target continuous-variable quantum key distribution systems that use the heterodyne detection protocol using either direct or reverse reconciliation. Our attack is proved to be feasible and renders all of the final key shared between the legitimate parties insecure, even if they have monitored the intensity of the local oscillator. To prevent our attack on commercial systems, a simple wavelength filter should be added before performing the monitoring detection.

  1. Methylsulfonyl and methoxysulfinyl radicals and cations in the gas phase. A variable-time and photoexcitation neutralization-reionization mass spectrometric and ab initio/RRKM study

    SciTech Connect

    Frank, A.J.; Turecek, F. [Univ. of Washington, Seattle, WA (United States). Dept. of Chemistry] [Univ. of Washington, Seattle, WA (United States). Dept. of Chemistry

    1999-07-08

    The oxidation cascade reactions converting the so-called reduced sulfur compounds (H{sub 2}S, dimethyl sulfide, dimethyl disulfide, etc.) to oxidized sulfur compounds (SO{sub 2}, sulfuric acid, and methanesulfonic acid) in the troposphere involve several reaction intermediates. The concentrations of these intermediates in the troposphere are very small, which makes direct observation and characterization difficult. The title radicals were produced by femtosecond collisional electron transfer in the gas phase and studied by the methods of variable-time neutralization-reionization mass spectrometry combined with fast-beam laser photoexcitation and G2(MP2) ab initio/RRKM calculations.

  2. Moderate physical exercise increases cardiac autonomic nervous system activity in children with low heart rate variability

    Microsoft Academic Search

    Narumi Nagai; Taku Hamada; Tetsuya Kimura; Toshio Moritani

    2004-01-01

    Object Our objective was to investigate the effect of a long-term moderate exercise program on cardiac autonomic nervous system (ANS) activity in healthy children. Methods Three hundred and five children aged 6–11 years participated in a 12-month school-based exercise training program (130–140 bpm, 20 min\\/day, 5 days\\/week). Cardiac ANS activities were measured using heart rate variability (HRV) power spectral analysis in resting conditions. Following

  3. Modeling and control of variable-speed wind-turbine drive-system dynamics

    Microsoft Academic Search

    P. Novak; T. Ekelund; I. Jovik; B. Schmidtbauer

    1995-01-01

    When designing control for variable-speed wind turbines, one deals with highly resonant, nonlinear dynamic systems subject to random excitation, i.e., wind turbulence. This requires good knowledge of the dynamics to be controlled, particularly when combined with the increasingly common “soft” concept of lightweight, flexible constructional components; it creates cost advantages compared to more material-consuming rigid constructions, but also results in

  4. Interannual Variability of the Kuroshio Extension System and Its Impact on the Wintertime SST Field

    Microsoft Academic Search

    Bo Qiu

    2000-01-01

    Altimetry data from the first 7-yr TOPEX\\/Poseidon (T\\/P) mission (October 1992-September 1999) are analyzed to investigate the interannual variability in regions of the Kuroshio Extension and its southern recirculation gyre. Large-scale, interannual changes of the Kuroshio Extension system are characterized by the oscillation between an elongated state and a contracted state. In the elongated state, the Kuroshio Extension has a

  5. A Theory of Interdecadal Climate Variability of the North Pacific Ocean-Atmosphere System

    Microsoft Academic Search

    Fei-Fei Jin

    1997-01-01

    A linear coupled model for the atmosphere-upper-ocean system is proposed to highlight the mechanisms of decadal to interdecadal climate variability in the North Pacific. In this model, wind stress anomalies over the North Pacific are related to anomalies in the meridional temperature gradient of the upper ocean. The latter depends upon air-sea thermodynamical feedbacks and meridional heat transport by upper-ocean

  6. Variable-length input Huffman coding for system-on-a-chip test

    Microsoft Academic Search

    Paul Theo Gonciari; Bashir M. Al-hashimi; Nicola Nicolici

    2003-01-01

    This paper presents a new compression method for embedded core-based system-on-a-chip test. In addition to the new compression method, this paper analyzes the three test data compression environment (TDCE) parameters: compression ratio, area overhead, and test application time, and explains the impact of the factors which influence these three parameters. The proposed method is based on a new variable-length input

  7. Energy simulation in the variable refrigerant flow air-conditioning system under cooling conditions

    Microsoft Academic Search

    Y. P. Zhou; J. Y. Wu; R. Z. Wang; S. Shiochi

    2007-01-01

    As a high-efficiency air-conditioning scheme, the variable refrigerant flow (VRF) air-conditioning system is finding its way in office buildings. However, there is no well-known energy simulation software available so far which can be used for the energy analysis of VRF. Based on the generic dynamic building energy simulation environment, EnergyPlus, a new VRF module is developed and the energy usage

  8. System Mass Variation and Entropy Generation in 100-kWe Closed-Brayton-Cycle Space Power Systems

    Microsoft Academic Search

    Michael J. Barrett; Bryan M. Reid

    2004-01-01

    State-of-the-art closed-Brayton-cycle (CBC) space power systems were modeled to study performance trends in a trade space characteristic of interplanetary orbiters. For working-fluid molar masses of 48.6, 39.9 and 11.9 kg\\/kmol, peak system pressures of 1.38 and 3.0 MPa and compressor pressure ratios ranging from 1.6 to 2.4, total system masses were estimated. System mass increased as peak operating pressure increased

  9. Mechanism studies of seasonal variability of dissolved oxygen in Mass Bay: A multi-scale FVCOM/UG-RCA application

    E-print Network

    Chen, Changsheng

    , Liuzhi Zhao b , Huichan Lin b a Department of Civil and Environmental Engineering, Great Lake Research Coastal Current (WMCC) together with freshwater discharge from the Merri- mack River. After entering, the Mass Bay ecosystem has experienced remarkable changes: increased outbreaks of harmful algal blooms

  10. Flow of variably fluidized granular masses across three-dimensional terrain 2. Numerical predictions and experimental tests

    Microsoft Academic Search

    Roger P. Denlinger; Richard M. Iverson

    2001-01-01

    Numerical solutions of the equations describing flow of variably fluidized Coulomb mixtures predict key features of dry granular avalanches and water-saturated debris flows measured in physical experiments. These features include time-dependent speeds, depths, and widths of flows as well as the geometry of resulting deposits. Three- dimensional (3-D) boundary surfaces strongly influence flow dynamics because transverse shearing and cross-stream momentum

  11. Predicting the Effects of Short-Term Photovoltaic Variability on Power System Frequency for Systems with Integrated Energy Storage

    NASA Astrophysics Data System (ADS)

    Traube, Joshua White

    The percentage of electricity supplied by photovoltaic (PV) generators is steadily rising in power systems worldwide. This rise in PV penetration may lead to larger fluctuations in power system frequency due to variability in PV generator output at time scales that fall between the inertial damping and automatic generation control (AGC) responses of power systems. To reduce PV generator variability, active power controls can be implemented in the power electronic inverters that interface PV generators to the power system. Although various types of active power controls have been developed, no standard methodology exists for evaluating the effectiveness of these controls at improving power system frequency regulation. This dissertation presents a method for predicting the effects of short-term PV variability on power system frequency for a PV generator with active power control provided by integrated energy storage. A custom model of a PV generator with integrated energy storage is implemented in a power system dynamic simulator and validated through experiments with a grid emulator. The model is used to predict the effects of short-term PV variability on the frequency of the IEEE 9-bus test power system modified to include a PV generator with integrated energy storage. In addition, this dissertation utilizes linear analysis of power system frequency control to predict worst-case frequency deviations as a function of the amount of energy storage integrated into PV generators. Through simulation and emulation on a scaled experimental prototype, the maximum frequency deviation caused by the PV generator with a small amount of integrated energy storage is found to be approximately 33% lower than the maximum frequency deviation caused by the PV generator alone. Through linear analysis it is shown that by adding only 36.7 kWh of integrated energy storage to a 1.2 MW PV system, the worst-case frequency deviation on the IEEE 9-bus test system can be reduced 65% from 0.45 Hz to 0.16 Hz. The techniques presented enable estimation of the maximum PV penetration or minimum integrated energy storage requirement to meet a frequency regulation target for a particular power system. Integrated energy storage can then be compared to other active power controls in order to choose a method that meets frequency control requirements at minimum cost.

  12. Fuzzy logic based intelligent control of a variable speed cage machine wind generation system

    SciTech Connect

    Simoes, M.G. [Univ. of Sao Paulo (Brazil)] [Univ. of Sao Paulo (Brazil); Bose, B.K. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Electrical Engineering] [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Electrical Engineering; Spiegel, R.J. [Environmental Protection Agency, Research Triangle Park, NC (United States), Air and Energy Engineering Research Lab.] [Environmental Protection Agency, Research Triangle Park, NC (United States), Air and Energy Engineering Research Lab.

    1997-01-01

    The paper describes a variable speed wind generation system where fuzzy logic principles are used for efficiency optimization and performance enhancement control. A squirrel cage induction generator feeds the power to a double-sided pulse width modulated converter system which pumps power to a utility grid or can supply to an autonomous system. The generation system has fuzzy logic control with vector control in the inner loops. A fuzzy controller tracks the generator speed with the wind velocity to extract the maximum power. A second fuzzy controller programs the machine flux for light load efficiency improvement, and a third fuzzy controller gives robust speed control against wind gust and turbine oscillatory torque. The complete control system has been developed, analyzed, and validated by simulation study. Performances have then been evaluated in detail.

  13. Stabilization of nonlinear systems with parametric uncertainty using variable structure techniques

    SciTech Connect

    Schoenwald, D.A. [Oak Ridge National Lab., TN (United States); Oezguener, Ue. [Ohio State Univ., Columbus, OH (United States). Dept. of Electrical Engineering

    1995-07-01

    The authors present a result on the robust stabilization of a class of nonlinear systems exhibiting parametric uncertainty. They consider feedback linearizable nonlinear systems with a vector of unknown constant parameters perturbed about a known value. A Taylor series of the system about the nominal parameter vector coupled with a feedback linearizing control law yields a linear system plus nonlinear perturbations. Via a structure matching condition, a variable structure control law is shown to exponentially stabilize the full system. The novelty of the result is that the linearizing coordinates are completely known since they are defined about the nominal parameter vector, and fewer restrictions are imposed on the nonlinear perturbations than elsewhere in the literature.

  14. Simulating extreme-mass-ratio systems in full general relativity

    NASA Astrophysics Data System (ADS)

    East, William E.; Pretorius, Frans

    2013-05-01

    We introduce a new method for numerically evolving the full Einstein field equations in situations where the spacetime is dominated by a known background solution. The technique leverages the knowledge of the background solution to subtract off its contribution to the truncation error, thereby more efficiently achieving a desired level of accuracy. We demonstrate the method by applying it to the radial infall of a solar-type star into supermassive black holes with mass ratios ?106. The self-gravity of the star is thus consistently modeled within the context of general relativity, and the star’s interaction with the black hole computed with moderate computational cost, despite the over five orders of magnitude difference in gravitational potential (as defined by the ratio of mass to radius). We compute the tidal deformation of the star during infall, and the gravitational wave emission, finding the latter is close to the prediction of the point-particle limit.

  15. Development and validation of the control variable transformation operators using the cubed-sphere grid system to represent a background error covariance

    NASA Astrophysics Data System (ADS)

    Kwun, Jihye; Song, Hyo-Jong; Ha, Ji-Hyun

    2014-05-01

    A background error covariance matrix is essential in a data assimilation system in terms of its spreading out dynamically balanced increments to the horizontal model grid points and the vertical levels. The full representation of the matrix is impossible because of its huge size, the matrix is therefore constructed implicitly by means of a control variable transformation. It is assumed that the forecast errors in the control variables are statistically independent. We utilized two approaches to dividing the unbalanced and the balanced parts; a method is using balance operators derived based on numerical discretization of partial differential equations, and the other is a regression-based approach. We used the spectral element method accompanying the cubed-sphere grid system, which guarantees a scalable performance in the configuration of using multiple CPUs. To model the background error covariance matrix, horizontal wind was decomposed into a rotational component and a divergent component by introducing stream function and velocity potential as control variables. The dynamical constraint of a balance between mass and wind was imposed by applying the linear balance operator and the nonlinear balance operator including cyclonic wind terms. The unbalanced velocity potential and the unbalanced mass variable is defined by using regression coefficients. The experimental background error statistics has been calculated by exploiting the ensemble samples of the Community Atmosphere Model (CAM) - Local Ensemble Transform Kalman Filter (LETKF). In order to understand the structure of the background error covariance, we performed single observation experiments using a three-dimensional variational data assimilation system on the cubed-sphere grid with the spectral transformation that was developed by Korea Institute of Atmospheric Prediction Systems(KIAPS) of which results will be presented.

  16. SCHEDULING IMPATIENT JOBS IN A CLEARING SYSTEM WITH INSIGHTS ON PATIENT TRIAGE IN MASS CASUALTY

    E-print Network

    Ziya, Serhan

    SCHEDULING IMPATIENT JOBS IN A CLEARING SYSTEM WITH INSIGHTS ON PATIENT TRIAGE IN MASS CASUALTY consider a single-server clearing system in which jobs may abandon the system if they are not taken into service within their "lifetime." In this system, jobs are characterized by their lifetime and service time

  17. Hydrogen isotope variability in prairie wetland systems: implications for studies of migratory connectivity.

    PubMed

    Bortolotti, Lauren E; Clark, Robert G; Wassenaar, Leonard I

    2013-01-01

    Hydrogen isotopes (delta2H) are often used to infer the origins of migratory animals based on the strong correlation between deuterium content of tissues and long-term patterns of precipitation. However, the extreme flood and drought dynamics of surface waters in prairie wetland systems could mask these expected correlations. We investigated H isotopic variability in an aquatic food web associated with Tree Swallows (Tachycineta bicolor) that rely heavily on wetland-derived aerial insects for food. We evaluated isotopic turnover and incorporation of environmental water into tissue, processes that could affect H isotopic composition. Wetland water and aquatic invertebrates showed intra- and interannual H isotopic variation mainly related to evaporation and the amount and timing of precipitation. Snails showed rapid turnover of tissue deuterium and a large contribution of environmental water to their tissues. Swallow feather deuterium (delta2Hf) was variable but did not clearly follow changes in any of the food web compartments measured. Instead, isotopic variability may have been driven by shifts in the type or relative amounts of grey consumed and types of wetlands used. Nevertheless, despite relatively high variance in delta2Hf, the majority of birds fell within the predicted range of delta2Hf for the study area, revealing that significant trophic averaging occurred. However, both (presumed) diet shifts and variable hydrological conditions have the potential to greatly increase variance that must be considered when assigning origins of migratory animals based on delta2H. PMID:23495640

  18. Fat-free mass in children and young adults predicted from bioelectric impedance and anthropometric variables13

    Microsoft Academic Search

    Shumei Guo; Alex F Roche; Linda Houtkooper

    Fat-free mass (FFM) values calculated from densitometry by using a multi- component model were significantly (p < 0.05) larger than those from the Siri two-component model (465 males, 441 females), especially in children and females. The multicomponent model assumes the density ofFFM varies by age and sex because ofdifferences in its constitu- ents. With FFM values from the multicomponent model

  19. Networking Mass Spectrometer Data Systems for Improved Productivity and Electronic Archiving of Data

    Microsoft Academic Search

    Mark J. Hayward; Paul V. Robandt; Jon T. Meek; Michael L. Thomson

    1993-01-01

    Several Finngan-MAT mass spectrometer data systems were networked together to achieve the following two primary objectives:\\u000a (1) to allow access to mass spectrometry data and data processing functions from remote locations without affecting simultaneous\\u000a data acquisition at the instruments, and (2) to electronically archive mass spectrometry data at a central location on a high-capacity,\\u000a fast-access device that allows rapid retrieval

  20. Development of Cellular Absorptive Tracers (CATs) for a Quantitative Characterization of Microbial Mass in Flow Systems

    SciTech Connect

    Saripalli, Prasad; Brown, Christopher F.; Lindberg, Michael J.

    2005-03-16

    We report on a new Cellular Absorptive Tracers (CATs) method, for a simple, non-destructive characterization of bacterial mass in flow systems. Results show that adsorption of a CAT molecule into the cellular mass results in its retardation during flow, which is a good, quantitative measure of the biomass quantity and distribution. No such methods are currently available for a quantitative characterization of cell mass.

  1. A Novel Variable Field System for Field-Cycled Dynamic Nuclear Polarization Spectroscopy

    PubMed Central

    Shet, Keerthi; Caia, George L.; Kesselring, Eric; Samouilov, Alexandre; Petryakov, Sergey; Lurie, David J.; Zweier, Jay L.

    2014-01-01

    Dynamic nuclear polarization (DNP) is an NMR-based technique which enables detection and spectral characterization of endogenous and exogenous paramagnetic substances measured via transfer of polarization from the saturated unpaired electron spin system to the NMR active nuclei. A variable field system capable of performing DNP spectroscopy with NMR detection at any magnetic field in the range 0 - 0.38 T is described. The system is built around a clinical open-MRI system. To obtain EPR spectra via DNP, partial cancellation of the detection field B0NMR is required to alter the evolution field B0EPR at which the EPR excitation is achieved. The addition of resistive actively shielded field cancellation coils in the gap of the primary magnet provides this field offset in the range of 0–100 mT. A description of the primary magnet, cancellation coils, power supplies, interfacing hardware, RF electronics and console are included. Performance of the instrument has been evaluated by acquiring DNP spectra of phantoms with aqueous nitroxide solutions (TEMPOL) at three NMR detection fields of 97 G, 200 G and 587 G corresponding to 413 kHz, 851.6 kHz and 2.5 MHz respectively and fixed EPR evolution field of 100 G corresponding to an irradiation frequency of 282.3 MHz. This variable field DNP system offers great flexibility for the performance of DNP spectroscopy with independent optimum choice of EPR excitation and NMR detection fields. PMID:20570197

  2. GAMMA-RAY VARIABILITY FROM WIND CLUMPING IN HIGH-MASS X-RAY BINARIES This article has been downloaded from IOPscience. Please scroll down to see the full text article.

    E-print Network

    Townsend, Richard

    GAMMA-RAY VARIABILITY FROM WIND CLUMPING IN HIGH-MASS X-RAY BINARIES WITH JETS This article has Society. All rights reserved. Printed in the U.S.A. GAMMA-RAY VARIABILITY FROM WIND CLUMPING IN HIGH from the star's radiatively driven wind, producing pions that then quickly decay into gamma rays. Since

  3. NSSDC Conference on Mass Storage Systems and Technologies for Space and Earth Science Applications, volume 2

    NASA Technical Reports Server (NTRS)

    Kobler, Ben (editor); Hariharan, P. C. (editor); Blasso, L. G. (editor)

    1992-01-01

    This report contains copies of nearly all of the technical papers and viewgraphs presented at the NSSDC Conference on Mass Storage Systems and Technologies for Space and Earth Science Application. This conference served as a broad forum for the discussion of a number of important issues in the field of mass storage systems. Topics include the following: magnetic disk and tape technologies; optical disk and tape; software storage and file management systems; and experiences with the use of a large, distributed storage system. The technical presentations describe, among other things, integrated mass storage systems that are expected to be available commercially. Also included is a series of presentations from Federal Government organizations and research institutions covering their mass storage requirements for the 1990's.

  4. Variability of water mass properties in the last two decades in the South Adriatic Sea with emphasis on the period 2006-2009

    NASA Astrophysics Data System (ADS)

    Cardin, Vanessa; Bensi, Manuel; Pacciaroni, Massimo

    2011-06-01

    Spatially averaged temperature and salinity profiles from individual cruises between 1990 and 2009 were analysed to outline the temporal evolution of water mass properties in the deep convection site in the South Adriatic Pit (SAP). The long-term variability in thermohaline conditions has been explained and related to a close feedback mechanism between the Ionian and the Adriatic Sea. Prominent influences of the Eastern Mediterranean Transient are manifested in changes in the vertical temperature and salinity patterns in the South Adriatic, and the whole studied period was divided into three stages according to the main thermohaline characteristics: 1990-1995, 1995-2004 and the last period from 2005 onwards. Particular attention was given to data collected during 2006-2009, which permitted us to situate the actual thermohaline properties in the context of the decadal variability. This last period was characterised by a very low production of dense water in the northern basin during 2007, while from winter 2008 high production of North Adriatic Deep Water (NAdDW) and Adriatic Deep Water (AdDW) in the northern and southern basins, respectively, was observed. Finally, we used the Optimum Multiparameter Analysis (OMP) to identify the percentages of the different water masses contained in the SAP, and this highlighted some differences between two recent periods studied (2007 and 2008) and the production of dense waters.

  5. All Effects of Psychophysical Variables on Color Attributes: A Classification System

    PubMed Central

    Pridmore, Ralph W.; Melgosa, Manuel

    2015-01-01

    This paper reports the research and structuring of a classification system for the effects of psychophysical variables on the color attributes. A basic role of color science is to psychophysically specify color appearance. An early stage is to specify the effects of the psychophysical variables (as singles, pairs, etc) on the color attributes (as singles, pairs, etc), for example to model color appearance. Current data on effects are often scarce or conflicting. Few effects are well understood, and the practice of naming effects after their discoverer(s) is inadequate and can be confusing. The number and types of possible effects have never been systematically analyzed and categorized. We propose a simple and rigorous system of classification including nomenclature. The total range of effects is computed from the possible combinations of three psychophysical variables (luminance, dominant wavelength, purity) and six color attributes (lightness, brightness, hue, chroma, colorfulness, saturation) in all modes of appearance. Omitting those effects that are normally impossible to perceive at any one time (such as four- or five-dimensional colors), the total number perceivable is 161 types of effects for all modes of appearance. The type of effect is named after the psychophysical stimulus (or stimuli) and the relevant color attribute(s), e.g., Luminance-on-hue effect (traditionally known as Bezold-Brucke effect). Each type of effect may include slightly different effects with infinite variations depending on experimental parameters. PMID:25859845

  6. Toward a Micro Gas Chromatograph/Mass Spectrometer (GC/MS) System

    NASA Technical Reports Server (NTRS)

    Wiberg, D. V.; Eyre, F. B.; Orient, O.; Chutjian, A.; Garkarian, V.

    2001-01-01

    Miniature mass filters (e.g., quadrupoles, ion traps) have been the subject of several miniaturization efforts. A project is currently in progress at JPL to develop a miniaturized Gas Chromatograph/Mass Spectrometer (GC/MS) system, incorporating and/or developing miniature system components including turbomolecular pumps, scroll type roughing pump, quadrupole mass filter, gas chromatograph, precision power supply and other electronic components. The preponderance of the system elements will be fabricated using microelectromechanical systems (MEMS) techniques. The quadrupole mass filter will be fabricated using an X-ray lithography technique producing high precision, 5x5 arrays of quadrupoles with pole lengths of about 3 mm and a total volume of 27 cubic mm. The miniature scroll pump will also be fabricated using X-ray lithography producing arrays of scroll stages about 3 mm in diameter. The target detection range for the mass spectrometer is 1 to 300 atomic mass units (AMU) with are solution of 0.5 AMU. This resolution will allow isotopic characterization for geochronology, atmospheric studies and other science efforts dependant on the understanding of isotope ratios of chemical species. This paper will discuss the design approach, the current state-of-the art regarding the system components and the progress toward development of key elements. The full system is anticipated to be small enough in mass, volume and power consumption to allow in situ chemical analysis on highly miniaturized science craft for geochronology, atmospheric characterization and detection of life experiments applicable to outer planet roadmap missions.

  7. Capacitor regenerative braking system of electric wheelchair for senior citizen based on variable frequency chopper control.

    PubMed

    Takahashi, Yoshiaki; Seki, Hirokazu

    2009-01-01

    This paper proposes a novel regenerative braking control system of electric wheelchairs for senior citizen. "Electric powered wheelchair", which generates the driving force by electric motors according to the human operation, is expected to be widely used as a mobility support system for elderly people. This study focuses on the braking control to realize the safety and smooth stopping motion using the regenerative braking control technique based on fuzzy algorithm. The ride quality improvement and energy recycling can be expected by the proposed control system with stopping distance estimation and variable frequency control on the step-up/down chopper type of capacitor regenerative circuit. Some driving experiments confirm the effectiveness of the proposed control system. PMID:19964689

  8. System enhancements of Mesoscale Analysis and Space Sensor (MASS) computer system

    NASA Technical Reports Server (NTRS)

    Hickey, J. S.; Karitani, S.

    1985-01-01

    The interactive information processing for the mesoscale analysis and space sensor (MASS) program is reported. The development and implementation of new spaceborne remote sensing technology to observe and measure atmospheric processes is described. The space measurements and conventional observational data are processed together to gain an improved understanding of the mesoscale structure and dynamical evolution of the atmosphere relative to cloud development and precipitation processes. A Research Computer System consisting of three primary computers was developed (HP-1000F, Perkin-Elmer 3250, and Harris/6) which provides a wide range of capabilities for processing and displaying interactively large volumes of remote sensing data. The development of a MASS data base management and analysis system on the HP-1000F computer and extending these capabilities by integration with the Perkin-Elmer and Harris/6 computers using the MSFC's Apple III microcomputer workstations is described. The objectives are: to design hardware enhancements for computer integration and to provide data conversion and transfer between machines.

  9. Use of a variable frequency motor controller to drive AC motor pumps on aircraft hydraulic systems

    SciTech Connect

    Motamed, F. [Martin Marietta Control Systems, Johnson City, NY (United States)

    1995-12-31

    This paper describes the development of a 20 kva Variable Frequency Motor Controller (VFMC) and its application to AC motor driven hydraulic pumps on aircraft. VFMC laboratory and iron bird testing has demonstrated: accommodation of variable frequency AC power (300--800Hz) to drive conventional fixed frequency induction motors, reduction of motor start inrush currents by 65% via soft starts, and reduction of AC motor pump electrical power demand by as much as 62% through power-on-demand control. As the VFMC transitions from technology demonstrator to flight qualified hardware, topics such as power quality, thermal management, electromagnetic compatibility, and system reliability have become more prominent, and the paper addresses their impact on the future direction of the VFMC.

  10. Characterizing the quiescent X-ray variability of the black hole low-mass X-ray binary V404 Cyg

    NASA Astrophysics Data System (ADS)

    Bernardini, F.; Cackett, E. M.

    2014-04-01

    We conducted the first long-term (75 d) X-ray monitoring of the black hole low-mass X-ray binary V404 Cyg, with the goal of understanding and characterizing its variability during quiescence. The X-ray light curve of V404 Cyg shows several flares on time-scales of hours with a count rate change of a factor of about 5-8. The root-mean-square variability is Fvar = 57.0 ± 3.2 per cent. The first-order structure function is consistent with both a power spectrum of index -1 (flicker noise), or with a power spectrum of index 0 (white noise), implying that the light curve is variable on time-scales from days to months. The X-ray spectrum is well fitted by a power law with spectral index ? = 2.10-2.35, and we found that the spectral shape remains roughly constant as the flux changes. A constant spectral shape with respect to a change in the X-ray flux may favour a scenario in which the X-ray emission is dominated by synchrotron radiation produced in a jet.

  11. Recent Greenland Ice Mass Loss by Drainage System from Satellite Gravity Observations

    Microsoft Academic Search

    S. B. Luthcke; H. J. Zwally; W. Abdalati; D. D. Rowlands; R. D. Ray; R. S. Nerem; F. G. Lemoine; J. J. McCarthy; D. S. Chinn

    2006-01-01

    Mass changes of the Greenland Ice Sheet resolved by drainage system regions were derived from a local mass concentration analysis of NASA Deutsches Zentrum für Luft- und Raumfahrt Gravity Recovery and Climate Experiment (GRACE mission) observations. From 2003 to 2005, the ice sheet lost 101 ± 16 gigaton\\/year, with a gain of 54 gigaton\\/year above 2000 meters and a loss

  12. System Identification and Automatic Mass Balancing of Ground-Based Three-Axis Spacecraft Simulator

    E-print Network

    System Identification and Automatic Mass Balancing of Ground-Based Three-Axis Spacecraft Simulator is considered. The method of estimating the inertial properties of a spacecraft as well as the location and the most observed behavior. A spherical air-bearing-based spacecraft testbed requires the center of mass

  13. A study of the mass loss rates of symbiotic star systems

    Microsoft Academic Search

    K. E. Korreck; E. Kellogg; J. L. Sokoloski

    2007-01-01

    The amount of mass loss in symbiotic systems is investigated, specifically mass loss via the formation of jets in R Aquarii (R Aqr). The jets in R Aqr have been observed in the X-ray by Chandra over a four year time period. The jet changes on times scales of a year and new outflows have been observed. Understanding the amount

  14. Evaluation of equilibrium trajectory of superconducting magnetic levitation system for the future kg unit of mass

    Microsoft Academic Search

    Fuyuhiko Shiota; Yukinobu Miki; Yusaku Fujii; Tadashi Morokuma; Yoshiaki Nezu

    2000-01-01

    The superconducting magnetic levitation system for absolute determination of magnetic flux quantum ?0, which is aimed at the future replacement of the kilogram unit of mass, has been developed at the National Research Laboratory of Metrology (NRLM) with a small floating body of approximately 25 g mass. The consistency of the relation between potential energy of the floating body and

  15. COMPUTER PROGRAM FOR REDUCING MASS SPECTRA DATA FROM GC/MS SYSTEMS

    EPA Science Inventory

    Existing computer programs for deconvoluting mass spectrometry data derived from gas chromatography/mass spectrometry/computer systems were evaluated, and the most efficient method was introduced into an EPA UNIVAC Computer. The program chosen was that reported by Rindfleisch and...

  16. Stability of Earth-Mass Planets in the Habitable Zones of Extrasolar Planetary Systems

    E-print Network

    Bjørnstad, Ottar Nordal

    Stability of Earth-Mass Planets in the Habitable Zones of Extrasolar Planetary Systems Dr. Ravi Kumar Kopparapu Dept. of Geosciences, College of Earth and Mineral Science Over 500 planets orbiting and Saturn but in the last couple of years several "super-earths", planets with mass less than 10 times Earth

  17. Comparative study of heat and mass exchanging materials for indirect evaporative cooling systems

    Microsoft Academic Search

    X. Zhao; Shuli Liu; S. B. Riffat

    2008-01-01

    This paper investigated several types of materials, namely metals, fibres, ceramics, zeolite and carbon, which have potential to be used as heat and mass transfer medium in the indirect evaporative cooling systems, and from the investigation, the most adequate material and structure were identified. Magnitude of heat\\/mass transfer rates in relation to an air-conditioning application was analysed, and the results

  18. Self-similar supersonic variable-density shear layers in binary systems

    NASA Astrophysics Data System (ADS)

    Kennedy, Christopher A.; Gatski, Thomas B.

    1994-02-01

    Some characteristic features of supersonic/supersonic, laminar, variable-density shear layers are studied by examining the self-similar behavior of five nitrogen/hydrogen streams. With the Levy-Lees transformation, the flow-field variables, which include the transverse velocity and dilatation, are obtained through the solution of the coupled set of nonlinear conservation equations. The issue of the appropriate ``third boundary condition,'' first given for the supersonic/supersonic case by Ting [J. Math. Phys. 28, 153 (1959)], is addressed and implemented in the present formulation. Expressions for the thermal conductivity, viscosity, specific heat, and binary diffusion coefficients of an arbitrary mixture are utilized so that the Prandtl and Lewis numbers and the Chapman-Rubesin parameter can vary freely across the shear layer. In the particular cases considered, these three quantities varied by factors of approximately 3, 7, and 22, respectively. The region of high vorticity moves toward the less-dense hydrogen stream for large density ratios (˜9:1), and becomes nearly decoupled from the density profile. Because the vorticity is responsible for the kinematic mixing of the two streams, this mixing of the two laminar streams is likely to be inhibited. Even though laminar flows are considered here, this effect is consistent with the experimental observation that as density ratios become very large, further increases in the density ratio have no effect on the turbulent shear layer growth rate. The density and hydrogen mass-fraction profiles are quite elongated in the transverse direction. An increase in the velocity ratio exaggerates both of these effects. Results obtained in this work are compatible with earlier work on incompressible, variable-density flows; more importantly, these results qualitatively resemble those from experiments of compressible and incompressible turbulent flows.

  19. Combined Structural and Trajectory Control of Variable-Geometry Planetary Entry Systems

    NASA Technical Reports Server (NTRS)

    Quadrelli, Marco B.; Pellegrino, Sergio; Kwok, Kawai

    2011-01-01

    Some of the key challenges of planetary entry are to dissipate the large kinetic energy of the entry vehicle and to land with precision. Past missions to Mars were based on unguided entry, where entry vehicles carried payloads of less than 0.6 T and landed within 100 km of the designated target. The Mars Science Laboratory (MSL) is expected to carry a mass of almost 1 T to within 20 km of the target site. Guided lifting entry is needed to meet these higher deceleration and targeting demands. If the aerodynamic characteristics of the decelerator are variable during flight, more trajectory options are possible, and can be tailored to specific mission requirements. In addition to the entry trajectory modulation, having variable aerodynamic properties will also favor maneuvering of the vehicle prior to descent. For proper supersonic parachute deployment, the vehicle needs to turn to a lower angle of attack. One approach to entry trajectory improvement and angle of attack control is to embed a variable geometry decelerator in the design of the vehicle. Variation in geometry enables the vehicle to adjust its aerodynamic performance continuously without additional fuel cost because only electric power is needed for actuating the mechanisms that control the shape change. Novel structural and control concepts have been developed that enable the decelerator to undergo variation in geometry. Changing the aerodynamic characteristics of a flight vehicle by active means can potentially provide a mechanically simple, affordable, and enabling solution for entry, descent, and landing across a wide range of mission types, sample capture and return, and reentry to Earth, Titan, Venus, or Mars. Unguided ballistic entry is not sufficient to meet this more stringent deceleration, heating, and targeting demands. Two structural concepts for implementing the cone angle variation, a segmented shell, and a corrugated shell, have been presented.

  20. Determining the spatial and temporal variability of Enceladus' mass-loading rate from ion-cyclotron wave observations and hybrid simulations

    NASA Astrophysics Data System (ADS)

    Powell, Ronald; Wei, Hanying; Cowee, Misa; Russell, Christopher; Leisner, Jared; Dougherty, Michele

    2014-05-01

    The southern plume of Enceladus releases a significant amount of neutrals, ions and dust into the inner magnetosphere of Saturn, thus it plays a critical role in the dynamics of plasma transport. The moon is also considered to be the ultimate source for the dusty E-ring and the extended neutral cloud from 3.5 to 6.5 Saturn radii. The mass loading rate from the plume can not only be directly measured from plasma instruments, but can also be obtained from the magnetic signatures produced by the plume and the properties of ion-cyclotron waves (ICW) generated by pickup ions from the plume. The ICWs grow from the free energy of the highly anisotropic distribution of the pickup ions, and their powers are proportional to the density and energy of the pickup ions. At Enceladus, ICWs are detected by Cassini not only near the moon but throughout the extended neutral cloud in all local times. However, the wave power is largely enhanced near the moon's longitude rather than far away from it. This indicates that on top of the relatively azimuthally symmetric mass-loading source of the neutral cloud, there is a much denser cloud of neutrals centered on the moon and rotating with it. The latter source is the instantaneous mass loading from Enceladus' plume, which leads to asymmetry and dynamics in the magnetosphere. From hybrid simulations, we study the ICW generation and understand the relationship between wave power and pickup ion densities. From observations, we obtain the spatial profiles of the ICW power near and far from the moon. Through comparison with waves at longitudes far away from the moon, we investigate how significant is the plume's mass-loading with respect to the neutral cloud mass-loading. We also compare the waves along several groups of identical trajectories and find that the temporal variability of the plume is within a factor of two.