Science.gov

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. Structural/control system optimization with variable actuator masses

    NASA Technical Reports Server (NTRS)

    Jin, Ik M.; Sepulveda, Abdon E.

    1993-01-01

    A method is presented to integrate the design space for structural/control system optimization problems in the case of linear state feedback control. Nonstructural lumped masses and control system design variables as well as structural sizing variables are all treated equally as independent design variables in the optimization process. Structural and control design variable linking schemes are used in order to avoid a prohibitively large increase in the total number of independent design variables. When actuator masses are treated as nonstructural lumped mass design variables, special consideration is given to the relation between the transient peak responses and the required actuator masses which is formulated as a behavior constraint form. The original nonlinear mathematical programming problem based on a finite element formulation and linear state feedback is replaced by a sequence of explicit approximate problems exploiting various approximation concepts such as design variable linkings, temporary constraint deletion and first order Taylor series expansion of nonlinear behavior constraints in terms of intermediate design variables. Examples which involve a variety of dynamic behavior constraints (including constraints on closed-loop eigenvalues, peak transient displacements, peak actuator forces, and relations between the peak responses and the actuator masses) are effectively solved by using the method presented.

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

    NASA Astrophysics Data System (ADS)

    Ganghoffer, Jean-François; Rahouadj, Rachid

    2016-03-01

    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. The third-order Lagrange equation for mechanical systems of variable mass

    NASA Astrophysics Data System (ADS)

    Ma, Shan-Jun; Ge, Wei-Guo; Huang, Pei-Tian

    2005-05-01

    In this paper, based on the third-order D'Alembert-Lagrange principle for mechanical systems of variable mass, the third-order Lagrange equations of mechanical systems of variable mass are obtained. From the equations the motion of mechanical systems of variable mass can be studied. In addition, the equations may enrich the theory of third-order differential equation.

  5. Kane's equations and Appell's equations for high order nonholonomic variable mass systems

    NASA Astrophysics Data System (ADS)

    Ge, Zheng-Ming; Wang, Tzu-Jun

    1991-04-01

    Based on the universal D'Alembert-Lagrange's principle for variable mass systems, by means of the new method of high-ordered variation, two forms of extended equations of motion are obtained for the high-ordered nonholonomic variable mass systems of which the corresponding conventional forms of equations of motion are the special cases. Kane's equations for high-ordered nonholonomic variable mass system are derived more naturally than Kane's original derivation in which the coefficients of generalized velocities are introduced somewhat artificially. Appell's equations expressed in energy of acceleration are extended for high-ordered nonholonomic variable mass systems.

  6. Atwood's Machine as a Tool to Introduce Variable Mass Systems

    ERIC Educational Resources Information Center

    de Sousa, Celia A.

    2012-01-01

    This article discusses an instructional strategy which explores eventual similarities and/or analogies between familiar problems and more sophisticated systems. In this context, the Atwood's machine problem is used to introduce students to more complex problems involving ropes and chains. The methodology proposed helps students to develop the…

  7. Dynamics of variable mass systems with application to the star 48 solid rocket motor

    NASA Technical Reports Server (NTRS)

    Eke, F. O.

    1984-01-01

    Existing methods for the derivation of equations of motion of variable mass systems are reviewed and compared, the end product being a system of general dynamical equations for variable mass systems. These equations are used to study the lateral stability problem associated with the Star 48 solid rocket engine. It is shown that the shape of the combustion chamber could have a significant effect on the lateral stability of the rocket; specifically, a short and wide combustion chamber is destabilizing, while a long and narrow chamber is stabilizing.

  8. Mass extinction in a dynamical system of evolution with variable dimension.

    PubMed

    Tokita, K; Yasutomi, A

    1999-07-01

    Introducing the effect of extinction into the so-called replicator equations in mathematical biology, we construct a general model where the diversity of species, i.e., the dimension of the equation, is a time-dependent variable. The system shows very different behavior from the original replicator equation, and leads to mass extinction when the system initially has high diversity. The present theory can serve as a mathematical foundation for the paleontologic theory for mass extinction. This extinction dynamics is a prototype of dynamical systems where the variable dimension is inevitable.

  9. Falling Chains as Variable-Mass Systems: Theoretical Model and Experimental Analysis

    ERIC Educational Resources Information Center

    de Sousa, Celia A.; Gordo, Paulo M.; Costa, Pedro

    2012-01-01

    In this paper, we revisit, theoretically and experimentally, the fall of a folded U-chain and of a pile-chain. The model calculation implies the division of the whole system into two subsystems of variable mass, allowing us to explore the role of tensional contact forces at the boundary of the subsystems. This justifies, for instance, that the…

  10. The dynamical mass of a classical Cepheid variable star in an eclipsing binary system.

    PubMed

    Pietrzyński, G; Thompson, I B; Gieren, W; Graczyk, D; Bono, G; Udalski, A; Soszyński, I; Minniti, D; Pilecki, B

    2010-11-25

    Stellar pulsation theory provides a means of determining the masses of pulsating classical Cepheid supergiants-it is the pulsation that causes their luminosity to vary. Such pulsational masses are found to be smaller than the masses derived from stellar evolution theory: this is the Cepheid mass discrepancy problem, for which a solution is missing. An independent, accurate dynamical mass determination for a classical Cepheid variable star (as opposed to type-II Cepheids, low-mass stars with a very different evolutionary history) in a binary system is needed in order to determine which is correct. The accuracy of previous efforts to establish a dynamical Cepheid mass from Galactic single-lined non-eclipsing binaries was typically about 15-30% (refs 6, 7), which is not good enough to resolve the mass discrepancy problem. In spite of many observational efforts, no firm detection of a classical Cepheid in an eclipsing double-lined binary has hitherto been reported. Here we report the discovery of a classical Cepheid in a well detached, double-lined eclipsing binary in the Large Magellanic Cloud. We determine the mass to a precision of 1% and show that it agrees with its pulsation mass, providing strong evidence that pulsation theory correctly and precisely predicts the masses of classical Cepheids.

  11. The dynamical mass of a classical Cepheid variable star in an eclipsing binary system.

    PubMed

    Pietrzyński, G; Thompson, I B; Gieren, W; Graczyk, D; Bono, G; Udalski, A; Soszyński, I; Minniti, D; Pilecki, B

    2010-11-25

    Stellar pulsation theory provides a means of determining the masses of pulsating classical Cepheid supergiants-it is the pulsation that causes their luminosity to vary. Such pulsational masses are found to be smaller than the masses derived from stellar evolution theory: this is the Cepheid mass discrepancy problem, for which a solution is missing. An independent, accurate dynamical mass determination for a classical Cepheid variable star (as opposed to type-II Cepheids, low-mass stars with a very different evolutionary history) in a binary system is needed in order to determine which is correct. The accuracy of previous efforts to establish a dynamical Cepheid mass from Galactic single-lined non-eclipsing binaries was typically about 15-30% (refs 6, 7), which is not good enough to resolve the mass discrepancy problem. In spite of many observational efforts, no firm detection of a classical Cepheid in an eclipsing double-lined binary has hitherto been reported. Here we report the discovery of a classical Cepheid in a well detached, double-lined eclipsing binary in the Large Magellanic Cloud. We determine the mass to a precision of 1% and show that it agrees with its pulsation mass, providing strong evidence that pulsation theory correctly and precisely predicts the masses of classical Cepheids. PMID:21107425

  12. Dynamics of a variable mass system applied to spacecraft rocket attitude theory

    NASA Astrophysics Data System (ADS)

    Mudge, Jason Dominic

    This research project is a study of the dynamics of a variable mass system. The scope of this research project is to gain understanding as to how a variable mass system will behave. The intent is to bring the level of understanding of variable mass dynamics higher and closer to the level of constant mass dynamics in the area of spacecrafts in particular. A main contribution is the finding of a set of criteria to minimize or eliminate the deviation of the nutation angle (or cone angle or angle of attack) of spacecraft rockets passively, i.e. without active control. The motivation for this research project is the Star 48 anomaly. The Star 48 is a solid rocket motor which has propelled (boosted) communication satellites from lower earth orbit to a higher one during the 1980's. The anomaly is that when the spacecraft rocket is being propelled, the nutation angle may deviate excessively which is considered undesirable. In the first part of this research project, a variable mass system is described and defined and the governing equations are derived. The type of governing equations derived are those that are most useful for analyzing the motion of a spacecraft rocket. The method of derivation makes use of Leibnitz Theorem, Divergence Theorem and Newton's Second Law of Motion. Next, the governing equations are specialized with several assumptions which are generally accepted assumptions applied in the analysis of spacecraft rockets. With these assumptions, the form governing equations is discussed and then the equations are solved analytically for the system's angular velocity. Having solved for the angular velocity of the system, the attitude of the system is obtained using a unique method which circumvents the nonlinearities that exist using Euler Angles and their kinematical equations. The attitude is approximately found analytically and a set of criteria is discussed which will minimize or eliminate the deviation of the nutation angle of a spacecraft rocket. Finally

  13. 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 = α D^β. 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 β 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 β can be calculated along the flight trajectory. Then the pre-factor α 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

  14. THE PHYSICS OF ELEMENTARY PARTICLES AND FIELDS: Conservation Laws for Partially Conservative Variable Mass Systems via d'Alembert's Principle

    NASA Astrophysics Data System (ADS)

    Aftab, Ahmed; Naseer, Ahmed; Qudrat, Khan

    2008-09-01

    Conservation laws for partially conservative variable mass dynamical systems under symmetric infinitesimal transformations are determined. A generalization of Lagrange-d'Alembert's principle for a variable mass system in terms of asynchronous virtual variation is presented. The generalized Killing equations are obtained such that their solution yields the transformations and the associated conservation laws. An example illustrative of the theory is furnished at the end as well.

  15. 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

  16. 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.

  17. Deep, Low Mass Ratio Overcontact Binary Systems. XIII. DZ Piscium with Intrinsic Light Variability

    NASA Astrophysics Data System (ADS)

    Yang, Y.-G.; Qian, S.-B.; Zhang, L.-Y.; Dai, H.-F.; Soonthornthum, B.

    2013-08-01

    New multi-color photometry for the eclipsing binary DZ Psc was performed in 2011 and 2012 using the 85 cm telescope at the Xinglong Station of the National Astronomical Observatories of China. Using the updated Wilson-Devinney (W-D) code, we deduced two sets of photometric solutions. The overcontact degree is f = 89.7(± 1.0)%, identifying DZ Psc as a deep, low mass ratio overcontact binary. The asymmetric light curves (i.e., LC2 in 2012) were modeled by a hot spot on the primary star. Based on all of the available light minimum times, we discovered that the orbital period of DZ Psc may be undergoing a secular period increase with a cyclic variation. The modulated period and semi-amplitude of this oscillation are P mod = 11.89(± 0.19) yr and A = 0.0064(± 0.0006) days, which may be possibly attributed to either cyclic magnetic activity or light-time effect due to the third body. The long-term period increases at a rate of dP/dt=+7.43(+/- 0.17)\\times 10^{-7}{\\,days\\, yr^{-1}}, which may be interpreted as conserved mass transfer from the less massive component to the more massive one. With mass transferring, DZ Psc will finally merge into a rapid-rotation single star when J spin/J orb > 1/3.

  18. Insights into the Earth System mass variability from CSR-RL05 GRACE gravity fields

    NASA Astrophysics Data System (ADS)

    Bettadpur, S.

    2012-04-01

    The next-generation Release-05 GRACE gravity field data products are the result of extensive effort applied to the improvements to the GRACE Level-1 (tracking) data products, and to improvements in the background gravity models and processing methodology. As a result, the squared-error upper-bound in RL05 fields is half or less than the squared-error upper-bound in RL04 fields. The CSR-RL05 field release consists of unconstrained gravity fields as well as a regularized gravity field time-series that can be used for several applications without any post-processing error reduction. This paper will describe the background and the nature of these improvements in the data products, and provide an error characterization. We will describe the insights these new series offer in measuring the mass flux due to diverse Hydrologic, Oceanographic and Cryospheric processes.

  19. Mass transfer cycles in cataclysmic variables

    NASA Technical Reports Server (NTRS)

    King, A. R.; Frank, J.; Kolb, U.; Ritter, H.

    1995-01-01

    It is well known that in cataclysmic variables the mass transfer rate must fluctuate about the evolutionary mean on timescales too long to be directly observable. We show that limit-cycle behavior can occur if the radius change of the secondary star is sensitive to the instantaneous mass transfer rate. The only reasonable way in which such a dependence can arise is through irradiation of this star by the accreting component. The system oscillates between high states, in which irradiation causes slow expansion of the secondary and drives an elevated transfer rate, and low states, in which this star contracts.

  20. 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.

  1. 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

  2. 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

  3. Variable contour securing system

    NASA Technical Reports Server (NTRS)

    Zebus, P. P.; Packer, P. N.; Haynie, C. C. (Inventor)

    1978-01-01

    A variable contour securing system has a retaining structure for a member whose surface contains a variable contour. The retaining mechanism includes a spaced array of adjustable spindles mounted on a housing. Each spindle has a base member support cup at one end. A vacuum source is applied to the cups for seating the member adjacent to the cups. A locking mechanism sets the spindles in a predetermined position once the member has been secured to the spindle support cups.

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

    SciTech Connect

    Lasota, J.-P.; Alexander, T.; Dubus, G.; Farrell, S. A.; Gehrels, N.

    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

  5. Mass Storage Systems.

    ERIC Educational Resources Information Center

    Ranade, Sanjay; Schraeder, Jeff

    1991-01-01

    Presents an overview of the mass storage market and discusses mass storage systems as part of computer networks. Systems for personal computers, workstations, minicomputers, and mainframe computers are described; file servers are explained; system integration issues are raised; and future possibilities are suggested. (LRW)

  6. Variable camshaft timing system

    SciTech Connect

    Butterfield, R.P.; Smith, F.R.

    1989-09-05

    This patent describes an improvement in a variable camshaft timing system for an internal combustion engine having intake and exhaust valves and a camshaft for each of the intake and exhaust valves, an intake sprocket and an exhaust sprocket keyed to their respective camshaft, only one of the camshafts being directly driven by an engine crankshaft, and a timing chain engaging both sprockets. The improvement comprising a single bracket carrying at least one idler sprocket engaging the timing chain, the bracket being mounted for movement to alter the timing relationship between the intake and exhaust sprockets.

  7. Ultra High Mass Range Mass Spectrometer System

    DOEpatents

    Reilly, Peter T. A. [Knoxville, TN

    2005-12-06

    Applicant's present invention comprises mass spectrometer systems that operate in a mass range from 1 to 10.sup.16 DA. The mass spectrometer system comprising an inlet system comprising an aerodynamic lens system, a reverse jet being a gas flux generated in an annulus moving in a reverse direction and a multipole ion guide; a digital ion trap; and a thermal vaporization/ionization detector system. Applicant's present invention further comprises a quadrupole mass spectrometer system comprising an inlet system having a quadrupole mass filter and a thermal vaporization/ionization detector system. Applicant's present invention further comprises an inlet system for use with a mass spectrometer system, a method for slowing energetic particles using an inlet system. Applicant's present invention also comprises a detector device and a method for detecting high mass charged particles.

  8. Variable camshaft timing system

    SciTech Connect

    Sapienza, S.J.

    1988-05-17

    A variable camshaft timing system in combination with an internal combustion engine having at least one cylinder, a rotatable member such as a crankshaft, and an intake and exhaust valve coupled to an intake camshaft and an exhaust camshaft respectively, the system is described comprising: a pulley wheel fixedly attached at one end of each of the intake and exhaust camshafts and the crankshaft; belt means interconnecting each of the pulley wheels for transferring rotational motion from the crankshaft to the intake and exhaust camshafts; first and second idler arm means pivotally attached to the engine, each of the idler arm means having a pivoting arm, a cam follower arm and an idler wheel in operative contact with the belt means; positioning cam means operatively coupled to each of the cam follower arms of the idler arm means; a control means responsive to various engine operating parameters for generating motor control signals; and electric motor means responsive to the motor control signals and operatively coupled to rotate the positioning cams means for positioning each of the idler arm means for changing the relative rotational position between the input camshaft and the exhaust camshaft.

  9. Mode Selection Techniques in Variable Mass Flexible Body Modeling

    NASA Technical Reports Server (NTRS)

    Quiocho, Leslie J.; Ghosh, Tushar K.; Frenkel, David; Huynh, An

    2010-01-01

    In developing a flexible body spacecraft simulation for the Launch Abort System of the Orion vehicle, when a rapid mass depletion takes place, the dynamics problem with time varying eigenmodes had to be addressed. Three different techniques were implemented, with different trade-offs made between performance and fidelity. A number of technical issues had to be solved in the process. This paper covers the background of the variable mass flexibility problem, the three approaches to simulating it, and the technical issues that were solved in formulating and implementing them.

  10. Variability in properties of Salado Mass Concrete

    SciTech Connect

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

    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.

  11. Modeling and Simulation of Variable Mass, Flexible Structures

    NASA Technical Reports Server (NTRS)

    Tobbe, Patrick A.; Matras, Alex L.; Wilson, Heath E.

    2009-01-01

    The advent of the new Ares I launch vehicle has highlighted the need for advanced dynamic analysis tools for variable mass, flexible structures. This system is composed of interconnected flexible stages or components undergoing rapid mass depletion through the consumption of solid or liquid propellant. In addition to large rigid body configuration changes, the system simultaneously experiences elastic deformations. In most applications, the elastic deformations are compatible with linear strain-displacement relationships and are typically modeled using the assumed modes technique. The deformation of the system is approximated through the linear combination of the products of spatial shape functions and generalized time coordinates. Spatial shape functions are traditionally composed of normal mode shapes of the system or even constraint modes and static deformations derived from finite element models of the system. Equations of motion for systems undergoing coupled large rigid body motion and elastic deformation have previously been derived through a number of techniques [1]. However, in these derivations, the mode shapes or spatial shape functions of the system components were considered constant. But with the Ares I vehicle, the structural characteristics of the system are changing with the mass of the system. Previous approaches to solving this problem involve periodic updates to the spatial shape functions or interpolation between shape functions based on system mass or elapsed mission time. These solutions often introduce misleading or even unstable numerical transients into the system. Plus, interpolation on a shape function is not intuitive. This paper presents an approach in which the shape functions are held constant and operate on the changing mass and stiffness matrices of the vehicle components. Each vehicle stage or component finite element model is broken into dry structure and propellant models. A library of propellant models is used to describe the

  12. Doubling down on peptide phosphorylation as a variable mass modification

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Some mass spectrometrists believe that searching for variable post-translational modifications like phosphorylation of serine or threonine when using database-search algorithms to interpret peptide tandem mass spectra will increase false positive rates. The basis for this is the premise that the al...

  13. Mass loss and OH maser emission from Mira variables

    NASA Technical Reports Server (NTRS)

    Michalitsianos, A. G.; Kafatos, M.

    1978-01-01

    The mass, radius, and luminosity of 26 Mira variables that are known OH sources of radio emission at 1612 MHz have been estimated. The time-independent solution of Salpeter's (1974) stellar-wind equation and a period-density relation are used to solve for basic stellar parameters, with the aid of the terminal expansion velocity of the OH maser cloud. Masses obtained from these calculations are consistent with other estimated values for masses of Mira variables. Good agreement is obtained when comparing the rate of mass loss as determined from Reimers's (1977) semiempirical relation with estimates of the mass-loss rate as deduced from theoretical models involving radiation pressure on grains. These calculations suggest a strong correlation between the mass-loss rate and the pulsation period. Arguments concerning the general properties of silicate grains from radiation-pressure-driven stellar-wind equations are discussed.

  14. 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.

  15. A variable acceleration calibration system

    NASA Astrophysics Data System (ADS)

    Johnson, Thomas H.

    2011-12-01

    A variable acceleration calibration system that applies loads using gravitational and centripetal acceleration serves as an alternative, efficient and cost effective method for calibrating internal wind tunnel force balances. Two proof-of-concept variable acceleration calibration systems are designed, fabricated and tested. The NASA UT-36 force balance served as the test balance for the calibration experiments. The variable acceleration calibration systems are shown to be capable of performing three component calibration experiments with an approximate applied load error on the order of 1% of the full scale calibration loads. Sources of error are indentified using experimental design methods and a propagation of uncertainty analysis. Three types of uncertainty are indentified for the systems and are attributed to prediction error, calibration error and pure error. Angular velocity uncertainty is shown to be the largest indentified source of prediction error. The calibration uncertainties using a production variable acceleration based system are shown to be potentially equivalent to current methods. The production quality system can be realized using lighter materials and a more precise instrumentation. Further research is needed to account for balance deflection, forcing effects due to vibration, and large tare loads. A gyroscope measurement technique is shown to be capable of resolving the balance deflection angle calculation. Long term research objectives include a demonstration of a six degree of freedom calibration, and a large capacity balance calibration.

  16. 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.

  17. Identifying Dynamically Induced Variability in Glacier Mass-Balance Records

    NASA Astrophysics Data System (ADS)

    Christian, J. E.; Siler, N.; Koutnik, M. R.; Roe, G.

    2015-12-01

    Glacier mass-balance (i.e., accumulation vs. ablation) provides a direct indicator of a glacier's relationship with climate. However, mass-balance records contain noise due to internal climate variability (i.e., from stochastic fluctuations in large-scale atmospheric circulation), which can obscure or bias trends in these relatively short timeseries. This presents a challenge in correctly identifying the signature of anthropogenic change. "Dynamical adjustment" is a technique that identifies patterns of variance shared between a climate timeseries of interest (e.g., mass-balance) and independent "predictor" variables associated with large-scale circulation (e.g., Sea Level Pressure, SLP, or Sea Surface Temperature, SST). Extracting the component of variance due to internal variability leaves a residual timeseries for which trends can more confidently be attributed to external forcing. We apply dynamical adjustments based on Partial Least Squares Regression to mass-balance records from South Cascade Glacier in Washington State and Wolverine and Gulkana Glaciers in Alaska, independently analyzing seasonal balance records to assess the dynamical influences on winter accumulation and summer ablation. Seasonally averaged North Pacific SLP and SST fields perform comparably as predictor variables, explaining 50-60% of the variance in winter balance and 30-40% of variance in summer balance for South Cascade and Wolverine Glaciers. Gulkana glacier, located further inland than the other two glaciers, is less closely linked to North Pacific climate variability, with the predictors explaining roughly one-third of variance in its winter and summer balance. We analyze the significance of linear trends in the raw and adjusted mass-balance records, and find that for all three glaciers, a) summer balance shows a statistically significant downward trend that is not substantially altered when dynamically induced variability is removed, and b) winter balance shows no statistically

  18. Spacecraft telecommunications system mass estimates

    NASA Astrophysics Data System (ADS)

    Yuen, J. H.; Sakamoto, L. L.

    1988-02-01

    Mass is the most important limiting parameter for present-day planetary spacecraft design, In fact, the entire design can be characterized by mass. The more efficient the design of the spacecraft, the less mass will be required. The communications system is an essential and integral part of planetary spacecraft. A study is presented of the mass attributable to the communications system for spacecraft designs used in recent missions in an attempt to help guide future design considerations and research and development efforts. The basic approach is to examine the spacecraft by subsystem and allocate a portion of each subsystem to telecommunications. Conceptually, this is to divide the spacecraft into two parts, telecommunications and nontelecommunications. In this way, it is clear what the mass attributable to the communications system is. The percentage of mass is calculated using the actual masses of the spacecraft parts, except in the case of CRAF. In that case, estimated masses are used since the spacecraft was not yet built. The results show that the portion of the spacecraft attributable to telecommunications is substantial. The mass fraction for Voyager, Galileo, and CRAF (Mariner Mark 2) is 34, 19, and 18 percent, respectively. The large reduction of telecommunications mass from Voyager to Galileo is mainly due to the use of a deployable antenna instead of the solid antenna on Voyager.

  19. Variable frequency microwave furnace system

    DOEpatents

    Bible, D.W.; Lauf, R.J.

    1994-06-14

    A variable frequency microwave furnace system designed to allow modulation of the frequency of the microwaves introduced into a furnace cavity for testing or other selected applications. The variable frequency microwave furnace system includes a microwave signal generator or microwave voltage-controlled oscillator for generating a low-power microwave signal for input to the microwave furnace. A first amplifier may be provided to amplify the magnitude of the signal output from the microwave signal generator or the microwave voltage-controlled oscillator. A second amplifier is provided for processing the signal output by the first amplifier. The second amplifier outputs the microwave signal input to the furnace cavity. In the preferred embodiment, the second amplifier is a traveling-wave tube (TWT). A power supply is provided for operation of the second amplifier. A directional coupler is provided for detecting the direction of a signal and further directing the signal depending on the detected direction. A first power meter is provided for measuring the power delivered to the microwave furnace. A second power meter detects the magnitude of reflected power. Reflected power is dissipated in the reflected power load. 5 figs.

  20. Variable frequency microwave furnace system

    DOEpatents

    Bible, Don W.; Lauf, Robert J.

    1994-01-01

    A variable frequency microwave furnace system (10) designed to allow modulation of the frequency of the microwaves introduced into a furnace cavity (34) for testing or other selected applications. The variable frequency microwave furnace system (10) includes a microwave signal generator (12) or microwave voltage-controlled oscillator (14) for generating a low-power microwave signal for input to the microwave furnace. A first amplifier (18) may be provided to amplify the magnitude of the signal output from the microwave signal generator (12) or the microwave voltage-controlled oscillator (14). A second amplifier (20) is provided for processing the signal output by the first amplifier (18). The second amplifier (20) outputs the microwave signal input to the furnace cavity (34). In the preferred embodiment, the second amplifier (20) is a traveling-wave tube (TWT). A power supply (22) is provided for operation of the second amplifier (20). A directional coupler (24) is provided for detecting the direction of a signal and further directing the signal depending on the detected direction. A first power meter (30) is provided for measuring the power delivered to the microwave furnace (32). A second power meter (26) detects the magnitude of reflected power. Reflected power is dissipated in the reflected power load (28).

  1. Guide to transverse projections and mass-constraining variables

    SciTech Connect

    Barr, A. J.; Khoo, T. J.; Lester, C. G.; Konar, P.; Kong, K.; Matchev, K. T.; Park, M.

    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.

  2. Near-infrared Variability in the 2MASS Calibration Fields: A Search for Planetary Transit Candidates

    NASA Technical Reports Server (NTRS)

    Plavchan, Peter; Jura, M.; Kirkpatrick, J. Davy; Cutri, Roc M.; Gallagher, S. C.

    2008-01-01

    The Two Micron All Sky Survey (2MASS) photometric calibration observations cover approximately 6 square degrees on the sky in 35 'calibration fields,' each sampled in nominal photometric conditions between 562 and 3692 times during the 4 years of the 2MASS mission. We compile a catalog of variables from the calibration observations to search for M dwarfs transited by extrasolar planets. We present our methods for measuring periodic and nonperiodic flux variability. From 7554 sources with apparent K(sub s) magnitudes between 5.6 and 16.1, we identify 247 variables, including extragalactic variables and 23 periodic variables. We have discovered three M dwarf eclipsing systems, including two candidates for transiting extrasolar planets.

  3. Movement simulation of the variable masses in the Gylden-Meshcherskii problem

    SciTech Connect

    Starinova, Olga L.; Salmin, Vadim V.

    2014-12-10

    The Gylden-Meshcherskii problem is used for various cases of dynamics of two points of the variable mass. For example, it describes of double star evolution due to mass loss at the photon expense and the corpuscular activity. Except, it is mathematical model for the movement of spacecraft with propulsion system. In the present work the mass variation laws, allowing a stationary form of the movement differential equations are considered. Movement simulation for all cases was conducted. The relative movement trajectories was constructed as for known Eddington-Jeans laws and for other mass variation laws.

  4. 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.

  5. Disambiguating seesaw models using invariant mass variables at hadron colliders

    DOE PAGESBeta

    Dev, P. S. Bhupal; Kim, Doojin; Mohapatra, Rabindra N.

    2016-01-19

    Here, we propose ways to distinguish between different mechanisms behind the collider signals of TeV-scale seesaw models for neutrino masses using kinematic endpoints of invariant mass variables. We particularly focus on two classes of such models widely discussed in literature: (i) Standard Model extended by the addition of singlet neutrinos and (ii) Left-Right Symmetric Models. Relevant scenarios involving the same "smoking-gun" collider signature of dilepton plus dijet with no missing transverse energy differ from one another by their event topology, resulting in distinctive relationships among the kinematic endpoints to be used for discerning them at hadron colliders. Furthermore, these kinematic endpoints are readily translated to the mass parameters of the on-shell particles through simple analytic expressions which can be used for measuring the masses of the new particles. We also conducted a Monte Carlo simulation with detector effects in order to test the viability of the proposed strategy in a realistic environment. Finally, we discuss the future prospects of testing these scenarios at themore » $$\\sqrt{s}$$ = 14 and 100TeV hadron colliders.« less

  6. Disambiguating seesaw models using invariant mass variables at hadron colliders

    NASA Astrophysics Data System (ADS)

    Dev, P. S. Bhupal; Kim, Doojin; Mohapatra, Rabindra N.

    2016-01-01

    We propose ways to distinguish between different mechanisms behind the collider signals of TeV-scale seesaw models for neutrino masses using kinematic endpoints of invariant mass variables. We particularly focus on two classes of such models widely discussed in literature: (i) Standard Model extended by the addition of singlet neutrinos and (ii) Left-Right Symmetric Models. Relevant scenarios involving the same "smoking-gun" collider signature of dilepton plus dijet with no missing transverse energy differ from one another by their event topology, resulting in distinctive relationships among the kinematic endpoints to be used for discerning them at hadron colliders. These kinematic endpoints are readily translated to the mass parameters of the on-shell particles through simple analytic expressions which can be used for measuring the masses of the new particles. A Monte Carlo simulation with detector effects is conducted to test the viability of the proposed strategy in a realistic environment. Finally, we discuss the future prospects of testing these scenarios at the √{s}=14 and 100 TeV hadron colliders.

  7. Development and Evaluation of a Variable-Temperature Quadrupole Ion Trap Mass Spectrometer.

    PubMed

    Derkits, David; Wiseman, Alex; Snead, Russell F; Dows, Martina; Harge, Jasmine; Lamp, Jared A; Gronert, Scott

    2016-02-01

    A new, variable-temperature mass spectrometer system is described. By applying polyimide heating tape to the end-cap electrodes of a Bruker (Bremen, Germany) Esquire ion trap, it is possible to vary the effective temperature of the system between 40 and 100°C. The modification does not impact the operation of the ion trap and the heater can be used for extended periods without degradation of the system. The accuracy of the ion trap temperatures was assessed by examining two gas-phase equilibrium processes with known thermochemistry. In each case, the variable-temperature ion trap provided data that were in good accord with literature data, indicating the effective temperature in the ion trap environment was being successfully modulated by the changes in the set-point temperatures on the end-cap electrodes. The new design offers a convenient and effective way to convert commercial ion trap mass spectrometers into variable-temperature instruments. PMID:26483183

  8. 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.

  9. Newtonian Version of the Variable Mass Theory of Gravity

    NASA Astrophysics Data System (ADS)

    Carvalho, J. C.; Lima, J. A. S.

    1990-11-01

    RESUMEN. Se presenta una versi6n Newtoniana de los modelos cosmol6gicos espacialmente e isotr6picos con masa variable. La influencia de la variaci6n de masa en la evoluci6n de la funci6n de escala est establecida para el caso de un Universo lieno de polvo bajo Ia suposici6n de que esta variaci6n es un efecto estrictamente cosmol6jico. Se muestra que el hiperb6lico, parab6lico 0 el#ptico dcl movimiento de puede ser modificado a lo larjo de la expansi6n. ABSTRACT. This paper presents a Newtonian version of the spatially homojeneous and isotropic cosmolojical models with variable mass. The influence of the mass variation on the evolution of the scale function is established for the case of a dust-filled Universe under the assumption that this variation is a strict cosmolojical effect. It is shown that the hyperbolic, parabolic or elliptic character of the fluid motion can be modified alonj the expansion. Keq : COSMOLOGY

  10. Pulsation-Driven Mass Loss in Luminous Blue Variables

    NASA Astrophysics Data System (ADS)

    Guzik, J. A.; Cox, A. N.; Despain, K. M.

    2005-09-01

    We use a nonlinear hydrodynamics code (Cox & Ostlie 1993) that includes a nonlocal time-dependent convection treatment to explore the pulsation of massive star models (Mo=50 and 80 M⊙) (see also Guzik et al. 1997, 1998, 1999). We find that for high-mass models near the Humphreys-Davidson limit, pulsations can grow to large amplitudes, exceeding 100 km/sec in radial velocity. The pulsations are similar to those of the LBV microvariations, with periods of 5 to 50 days, and light curve variations of about 0.1 mag. Ionization of Fe-group elements is occurring in the envelope at 200,000-500,000 K, producing a convective region that transports a varying amount of the emergent luminosity during the pulsation cycle. Because convection takes some time to turn on and off during a pulsation cycle, the outgoing radiation is periodically dammed up, and the Eddington limit is exceeded locally for that part of the pulsation cycle. The impulse imparted to the outer layers causes a large abrupt increase in their outward motion, which may be the beginning of an LBV `outburst'. Rotation (not included in these models) will also lower the effective gravitational binding of the outer layers. Since the envelopes of these stars contain only ˜10-4 M⊙, this mechanism perhaps could initiate mass loss of at most a few times x 10-4 M⊙/yr, in agreement with observed mass loss rates of LBV stars during an outburst. It is likely that the mass loss rate would be variable, modulated by the build-up of pulsation amplitude, requiring several pulsation cycles to accelerate, and would occur in shells or clumps. We suggest that this mechanism is responsible for the winds and outbursts of `normal' LBV stars such as S Dor or AG Car (Humphreys & Davidson 1994).

  11. Proportionally off-mass-shell equation for unequal mass systems

    NASA Astrophysics Data System (ADS)

    Maung Maung, Khin; Norbury, John W.; Kahana, David E.

    1996-03-01

    A new two-body relativistic equation is presented. The major advantage of the proposed equation over existing equations in the literature is that this equation automatically adjusts itself for different mass systems. Besides unitarity and covariance, this equation gives a physically meaningful prescription of how the particles go off-mass-shell in the intermediate states. It allows the particles to go off-mass-shell proportionally to their masses so that when one of the masses becomes infinite, it automatically becomes a one-body equation for the lighter particle and for equal mass systems, it reduces to the Todorov equation. Because of the off-mass-shell prescription for the intermediate states, it will be useful for systems with a wide variety of masses such as mesons, positronium, muonium, pionium, the deuteron and light hadronic atoms.

  12. Binary system parameters and the hibernation model of cataclysmic variables

    SciTech Connect

    Livio, M.; Shara, M.M.

    1987-08-01

    The hibernation model, in which nova systems spend most of the time between eruptions in a state of low mass transfer rate, is examined. The binary systems more likely to undergo hibernation are determined. The predictions of the hibernation scenario are shown to be consistent with available observational data. It is shown how the hibernation scenario provides links between classical novae, dwarf novae, and novalike variables, all of which represent different stages in the cyclic evolution of the same systems. 72 references.

  13. 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.

  14. Investigating glacial mass balance variability around the Prince Gustav Channel

    NASA Astrophysics Data System (ADS)

    Royston, Samantha; Gudmundsson, Hilmar; Clarke, Lucy; Fox, Adrian

    2015-04-01

    Glaciers on the Antarctic Peninsula have shown a varied response to recent climatic change. Most commonly, AP tidewater glaciers have retreated at the calving front and their flow rate has accelerated, increasing the contribution to sea level rise. Here, we utilise the results from a new photogrammetric technique that unlocks the archives of aerial photography from the 1940's to present, to investigate the driving mechanisms of glacier mass change on the AP over this period. Surface DEMs at different epochs have been derived using the new technique for a number of individual glacier basins. A higher-order vertically-integrated ice stream model is used to investigate the driving mechanisms of change for the area around the Prince Gustav Channel, incorporating basins covered by the new datasets. The Prince Gustav Ice Shelf collapsed in January 1995, followed by significant frontal retreat and speed up of its tributary glaciers. Additionally, significant changes have been observed for non-tributary glaciers such as Whisky Glacier on James Ross Island. Here, we investigate the sensitivity of this region's glaciers to ice shelf collapse, atmospheric and oceanic variability.

  15. 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.

  16. Alternative variable transformation for simulation of multibody dynamic systems

    NASA Astrophysics Data System (ADS)

    Yang, Li-Farn

    1995-03-01

    An alternative variable transformation is proposed and analyzed for the simulation of multibody dynamic systems. The developed alternative variable transformation matrix intended to work directly with the multibody equations of motion without altering the inherent dynamic characteristics also eliminates the need for expensive computation of inversion of a large mass matrix required for the simulation of multibody dynamic systems. From the analytical derivation of an articulated multibody model, it was found that the computation can be saved (3n + 1/4)-fold due to the computational merits associated with the band matrix.

  17. 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

    Various mass analyzer systems were evaluated. Several systems show promise, including the Stanford Research Systems RGA-100, Inficon XPR-2, the University of Florida's Ion Trap, and the Compact Double Focus Mass Spectrometer. Areas that need improvement are the response time, recovery time, system volume, and system weight. Future work will investigate techniques to improve systems and will evaluate engineering challenges.

  18. 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.

  19. Temporal variability of mass transport across Canary Islands Channels

    NASA Astrophysics Data System (ADS)

    Marrero-Díaz, Ángeles; Rodríguez-Santana, Ángel; José Machín, Francisco; García-Weil, Luis; Sangrà, Pablo; Vélez-Belchí, Pedro; Fraile-Nuez, Eugenio

    2014-05-01

    The equatorward flowing Canary Current (CC) is the main feature of the circulation in the Canary Islands region. The CC flow perturbation by the Canary Islands originate the Canary Eddy Corridor which is the major pathway for long lived eddies in the subtropical North Atlantic (Sangrà et al., 2009, DSR). Therefore the variability of the CC passing through the Canary Archipelago will have both local and regional importance. Past studies on the CC variability trough the Canary Islands point out a clearly seasonal variability (Fraile-Nuez et al, 2010 (JGR); Hernández-Guerra et al, 2002 (DSR)). However those studies where focused on the eastern islands channels missing the variability through the western island channels which are the main source of long lived eddies. In order to fill this gap from November 2012 until September 2013 we conducted trimonthly surveys crossing the whole islands channels using opportunity ships (Naviera Armas Ferries). XBT and XCTD where launched along the cross channels transects. Additionally a closed box circling the Archipelago was performed on October 2013 as part of the cruise RAPROCAN-2013 (IEO) using also XBT and XCTD. Dynamical variables where derived inferring salinity from S(T,p) analytical relationships for the region updated with new XCTD data. High resolution, vertical sections of temperature, potential density, geostrophic velocity and transport where obtained. Our preliminary results suggest that the CC suffer a noticeable acceleration in those islands channels where eddy shedding is more frequent. They also indicate a clearly seasonal variability of the flows passing the islands channels. With this regard we observed significant differences on the obtained seasonal variability with respect the cited past studies on the eastern islands channel (Lanzarote / Fuerteventura - Africa coast). This work was co-funded by Canary Government (TRAMIC project: PROID20100092) and the European Union (FEDER).

  20. Interesting examples of supervised continuous variable systems

    NASA Technical Reports Server (NTRS)

    Chase, Christopher; Serrano, Joe; Ramadge, Peter

    1990-01-01

    The authors analyze two simple deterministic flow models for multiple buffer servers which are examples of the supervision of continuous variable systems by a discrete controller. These systems exhibit what may be regarded as the two extremes of complexity of the closed loop behavior: one is eventually periodic, the other is chaotic. The first example exhibits chaotic behavior that could be characterized statistically. The dual system, the switched server system, exhibits very predictable behavior, which is modeled by a finite state automaton. This research has application to multimodal discrete time systems where the controller can choose from a set of transition maps to implement.

  1. A New Sample of Low-Mass AGNs Selected by X-ray Variability

    NASA Astrophysics Data System (ADS)

    Terashima, Yuichi

    2012-09-01

    We present results from our attempts to search for AGN containing relatively low-mass black holes (BHs) using X-ray variability. Variability time scales inversely correlate with black hole mass and can be used to select low-mass objects. We utilize the second XMM-Newton serendipitous source catalogue, which contains 262902 unique sources, to select highly variable objects. Black hole masses are derived by using the correlation between BH mass and normalized excess variance, where the effect of break in power spectra is properly taken into account. We present the sample selection and results of analysis including discovery of candidate low-mass AGNs with mass lower than 2e6 Msolar. We also present results on a peculiar AGN candidate showing soft thermal emission only found in our survey.

  2. Preliminary experimental results on studying possibility of variable mass liner (VML) formation

    SciTech Connect

    1995-12-31

    The main objective of the present experiment was to study the formation process and initial stage of acceleration of a variable-mass plasma liner (VML). The method is based on magnetic acceleration of a liner with the mass reduced during such acceleration. The experiment was carried out on February 16 at VNIIEF. This report describes the results of measurements obtained in the experiment and preliminary analysis of the results characterizing operation of the test facility main units: helical EMG; 5-module disk EMG 400 mm in diameter (DEMG); ponderomotive unit (PU) with a cylindric condensed liner and a special tooth-cutoff. The first part of the report presents measurement results obtained on the VNIIEF`s diagnostic equipment that are compared with those obtained by American specialists on their diagnostic equipment. Information submitted by American specialists is included in part 2 of this report. The second part of the report presents preliminary computational-theoretic analysis of the main measured results describing operation of DEMG TL system in the experiment; experimental data are compared with theoretical ones obtained before and after the experiment. But more emphasis is placed on the data preliminary analysis indicating that in the experiment a variable mass liner is formed (VML or plasma bubble).

  3. Variable pressure power cycle and control system

    DOEpatents

    Goldsberry, Fred L.

    1984-11-27

    A variable pressure power cycle and control system that is adjustable to a variable heat source is disclosed. The power cycle adjusts itself to the heat source so that a minimal temperature difference is maintained between the heat source fluid and the power cycle working fluid, thereby substantially matching the thermodynamic envelope of the power cycle to the thermodynamic envelope of the heat source. Adjustments are made by sensing the inlet temperature of the heat source fluid and then setting a superheated vapor temperature and pressure to achieve a minimum temperature difference between the heat source fluid and the working fluid.

  4. Motion planning for variable inertia mechanical systems

    NASA Astrophysics Data System (ADS)

    Shammas, Elie A.; Choset, Howie; Rizzi, Alfred A.

    2006-05-01

    In this paper, we generate gaits for mixed systems, that is, dynamic systems that are subject to a set of nonholonomic constraints. What is unique about mixed systems is that when we express their dynamics in body coordinates, the motion of these systems can be attributed to two decoupled terms: the geometric and dynamic phase shifts. In our prior work, we analyzed systems whose dynamic phase shift was null by definition. Purely mechanical and principally kinematic systems are two classes of mechanical systems that have this property. We generated gaits for these two classes of systems by intuitively evaluating their geometric phase shift and relating it to a volume integral under well-defined height functions. One of the contributions of this paper is to present a similar intuitive approach for computing the dynamic phase shift. We achieve this, by introducing a new scaled momentum variable that not only simplifies the momentum evolution equation but also allows us to introduce a new set of well-defined gamma functions which enable us to intuitively evaluate the dynamic phase shift. More specifically, by analyzing these novel gamma functions in a similar way to how we analyzed height functions, and by analyzing the sign-definiteness of the scaled momentum variable, we are able to ensure that the dynamic phase shift is non-zero solely along the desired fiber direction. Finally, we also introduce a novel mechanical system, the variable inertia snakeboard, which is a generalization of the original snakeboard that was previously studied in the literature. Not only does this general system help us identify regions of the base space where we can not define a certain type of gaits, but also it helps us verify the generality and applicability of our gait generation approach.

  5. Variable Acceleration Force Calibration System (VACS)

    NASA Technical Reports Server (NTRS)

    Rhew, Ray D.; Parker, Peter A.; Johnson, Thomas H.; Landman, Drew

    2014-01-01

    Conventionally, force balances have been calibrated manually, using a complex system of free hanging precision weights, bell cranks, and/or other mechanical components. Conventional methods may provide sufficient accuracy in some instances, but are often quite complex and labor-intensive, requiring three to four man-weeks to complete each full calibration. To ensure accuracy, gravity-based loading is typically utilized. However, this often causes difficulty when applying loads in three simultaneous, orthogonal axes. A complex system of levers, cranks, and cables must be used, introducing increased sources of systematic error, and significantly increasing the time and labor intensity required to complete the calibration. One aspect of the VACS is a method wherein the mass utilized for calibration is held constant, and the acceleration is changed to thereby generate relatively large forces with relatively small test masses. Multiple forces can be applied to a force balance without changing the test mass, and dynamic forces can be applied by rotation or oscillating acceleration. If rotational motion is utilized, a mass is rigidly attached to a force balance, and the mass is exposed to a rotational field. A large force can be applied by utilizing a large rotational velocity. A centrifuge or rotating table can be used to create the rotational field, and fixtures can be utilized to position the force balance. The acceleration may also be linear. For example, a table that moves linearly and accelerates in a sinusoidal manner may also be utilized. The test mass does not have to move in a path that is parallel to the ground, and no re-leveling is therefore required. Balance deflection corrections may be applied passively by monitoring the orientation of the force balance with a three-axis accelerometer package. Deflections are measured during each test run, and adjustments with respect to the true applied load can be made during the post-processing stage. This paper will

  6. [Complex systems variability analysis using approximate entropy].

    PubMed

    Cuestas, Eduardo

    2010-01-01

    Biological systems are highly complex systems, both spatially and temporally. They are rooted in an interdependent, redundant and pleiotropic interconnected dynamic network. The properties of a system are different from those of their parts, and they depend on the integrity of the whole. The systemic properties vanish when the system breaks down, while the properties of its components are maintained. The disease can be understood as a systemic functional alteration of the human body, which present with a varying severity, stability and durability. Biological systems are characterized by measurable complex rhythms, abnormal rhythms are associated with disease and may be involved in its pathogenesis, they are been termed "dynamic disease." Physicians have long time recognized that alterations of physiological rhythms are associated with disease. Measuring absolute values of clinical parameters yields highly significant, clinically useful information, however evaluating clinical parameters the variability provides additionally useful clinical information. The aim of this review was to study one of the most recent advances in the measurement and characterization of biological variability made possible by the development of mathematical models based on chaos theory and nonlinear dynamics, as approximate entropy, has provided us with greater ability to discern meaningful distinctions between biological signals from clinically distinct groups of patients.

  7. [Complex systems variability analysis using approximate entropy].

    PubMed

    Cuestas, Eduardo

    2010-01-01

    Biological systems are highly complex systems, both spatially and temporally. They are rooted in an interdependent, redundant and pleiotropic interconnected dynamic network. The properties of a system are different from those of their parts, and they depend on the integrity of the whole. The systemic properties vanish when the system breaks down, while the properties of its components are maintained. The disease can be understood as a systemic functional alteration of the human body, which present with a varying severity, stability and durability. Biological systems are characterized by measurable complex rhythms, abnormal rhythms are associated with disease and may be involved in its pathogenesis, they are been termed "dynamic disease." Physicians have long time recognized that alterations of physiological rhythms are associated with disease. Measuring absolute values of clinical parameters yields highly significant, clinically useful information, however evaluating clinical parameters the variability provides additionally useful clinical information. The aim of this review was to study one of the most recent advances in the measurement and characterization of biological variability made possible by the development of mathematical models based on chaos theory and nonlinear dynamics, as approximate entropy, has provided us with greater ability to discern meaningful distinctions between biological signals from clinically distinct groups of patients. PMID:21450141

  8. 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.

  9. Orbital Stability of High Mass Planetary Systems

    NASA Astrophysics Data System (ADS)

    Morrison, Sarah J.; Kratter, Kaitlin M.

    2016-05-01

    In light of the observation of systems like HR 8799 that contain several planets with planet-star mass ratios larger than Jupiter's, we explore the relationships between planet separation, mass, and stability timescale for high mass multi-planet systems detectable via direct imaging. We discuss the role of overlap between 1st and sometimes 2nd order mean motion resonances, and show how trends in stability time vary from previous studies of lower mass multi-planet systems. We show that extrapolating empirically derived relationships between planet mass, separation, and stability timescale derived from lower mass planetary systems misestimate the stability timescales for higher mass planetary systems by more than an order of magnitude at separations near the Hill stability limit. We also address what metrics of planet separation are most useful for estimating a system's dynamical stability. We apply these results to young, gapped, debris disk systems of the ScoCen association in order to place limits on the maximum mass and number of planets that could persist for the lifetimes of the disks. These efforts will provide useful constraints for on-going direct imaging surveys. By setting upper limits on the most easily detectable systems, we can better interpret both new discoveries and non-dectections.

  10. Disentanglement in bipartite continuous-variable systems

    SciTech Connect

    Barbosa, F. A. S.; Coelho, A. S.; Nussenzveig, P.; Martinelli, M.; Faria, A. J. de; Cassemiro, K. N.; Villar, A. S.

    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.

  11. Dynamically variable spot size laser system

    NASA Technical Reports Server (NTRS)

    Gradl, Paul R. (Inventor); Hurst, John F. (Inventor); Middleton, James R. (Inventor)

    2012-01-01

    A Dynamically Variable Spot Size (DVSS) laser system for bonding metal components includes an elongated housing containing a light entry aperture coupled to a laser beam transmission cable and a light exit aperture. A plurality of lenses contained within the housing focus a laser beam from the light entry aperture through the light exit aperture. The lenses may be dynamically adjusted to vary the spot size of the laser. A plurality of interoperable safety devices, including a manually depressible interlock switch, an internal proximity sensor, a remotely operated potentiometer, a remotely activated toggle and a power supply interlock, prevent activation of the laser and DVSS laser system if each safety device does not provide a closed circuit. The remotely operated potentiometer also provides continuous variability in laser energy output.

  12. The water mass variability on the Romanian Black Sea shelf

    NASA Astrophysics Data System (ADS)

    Buga, Luminita; Mihailov, Maria-Emanuela; Malciu, Viorel; Stefan, Sabina

    2013-04-01

    The long-term trends in the water mass thermohaline structure and the effect of Danube River freshwater discharge into the western Black Sea during the last four decades (1971 - 2010) are analyzed using the data collected on the Romanian shelf (NIMRD data base). The variations of the temperature and salinity over the studied period are relatively small. The temperature data reveal a slightly warming trend for the upper mixed layer (UML) while for the shelf cold water (SCW) - identified by the 8˚C upper isotherm depth - thermohaline structure remains practically constant. At the same time the salinity exhibits a decreasing trend in the entire water column.

  13. 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.

  14. Mass spectrometry in systems biology an introduction.

    PubMed

    Dunn, Warwick B

    2011-01-01

    The qualitative detection, quantification, and structural characterization of analytes in biological systems are important requirements for objectives to be fulfilled in systems biology research. One analytical tool applied to a multitude of systems biology studies is mass spectrometry, particularly for the study of proteins and metabolites. Here, the role of mass spectrometry in systems biology will be assessed, the advantages and disadvantages discussed, and the instrument configurations available described. Finally, general applications will be briefly reviewed.

  15. Quantum Information with Continuous Variable systems

    NASA Astrophysics Data System (ADS)

    Rodó, Carles

    2010-05-01

    This thesis deals with the study of quantum communication protocols with Continuous Variable (CV) systems. Continuous Variable systems are those described by canonical conjugated coordinates x and p endowed with infinite dimensional Hilbert spaces, thus involving a complex mathematical structure. A special class of CV states, are the so-called Gaussian states. With them, it has been possible to implement certain quantum tasks as quantum teleportation, quantum cryptography and quantum computation with fantastic experimental success. The importance of Gaussian states is two-fold; firstly, its structural mathematical description makes them much more amenable than any other CV system. Secondly, its production, manipulation and detection with current optical technology can be done with a very high degree of accuracy and control. Nevertheless, it is known that in spite of their exceptional role within the space of all Continuous Variable states, in fact, Gaussian states are not always the best candidates to perform quantum information tasks. Thus non-Gaussian states emerge as potentially good candidates for communication and computation purposes.

  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. 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.

  18. Efficient State Tomography for Continuous Variable Systems

    NASA Astrophysics Data System (ADS)

    Shen, Chao; Jiang, Luyao; Krastanov, Stefan; Albert, Victor V.; Heeres, Reinier; Vlastakis, Brian; Schoelkopf, Rob; Jiang, Liang

    2015-03-01

    We propose an efficient and error robust scheme for state tomography of a continuous variable system, which is dispersively coupled to a two-level system. Our adaptive tomography protocol offers a significant speed up compared to the conventional Wigner tomography for a practically interesting class of states, such as Schrodinger cat states. In the presence of typical experimental errors, the number of measurements required is still close to the information theoretic limit. Our proposals can be readily implemented in platforms such as superconducting transmon qubit inside a microwave cavity.

  19. Variability And Mass-loss From Agb Stars In The Lmc

    NASA Astrophysics Data System (ADS)

    Riebel, David; Meixner, M.; Srinivasan, S.; Fraser, O.; Babler, B.; Block, M.; Bracker, S.; Engelbracht, S.; Gordon, K.; Hora, J.; Indebetouw, R.; Leitherer, C.; Meade, M.; Misselt, K.; Whitney, B.; Sewilo, M.; Vijh, U.

    2009-01-01

    Mass loss from evolved stars on the Asymptotic Giant Branch (AGB) is an important factor in both stellar and galactic evolution; the total amount of mass lost determines the star's eventual fate as a compact object and plays a significant role in the chemical enrichment of the interstellar medium. We combine excess infrared emission derived by Srinivasan et al. (2008) from the Spitzer SAGE survey of the LMC (Meixner, et al. 2006) with variability parameters derived from the MACHO survey (Fraser, et al. 2008, in press) to examine the effects of stellar variability on mass loss from evolved stars on the AGB. We find that stellar populations differing in chemical composition show different relationships between mass loss and the period and amplitude of variation, while general trends of increasing mass loss with increasing variability are visible in all populations.

  20. 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.

  1. Equations of motion for the variable mass flow-variable exhaust velocity rocket

    NASA Technical Reports Server (NTRS)

    Tempelman, W. H.

    1972-01-01

    An equation of motion for a one dimensional rocket is derived as a function of the mass flow rate into the acceleration chamber and the velocity distribution along the chamber, thereby including the transient flow changes in the chamber. The derivation of the mass density requires the introduction of the special time coordinate. The equation of motion is derived from both classical force and momentum approaches and is shown to be consistent with the standard equation expressed in terms of flow parameters at the exit to the acceleration chamber.

  2. Variable stars in the VVV globular clusters. I. 2MASS-GC 02 and Terzan 10

    SciTech Connect

    Alonso-García, Javier; Dékány, István; Catelan, Márcio; Ramos, Rodrigo Contreras; Gran, Felipe; Leyton, Paul; Minniti, Dante; Amigo, Pía E-mail: idekany@astro.puc.cl E-mail: rcontrer@astro.puc.cl E-mail: pia.amigo@uv.cl E-mail: dante@astrofisica.cl

    2015-03-01

    The VISTA Variables in the Vía Láctea (VVV) ESO Public Survey is opening a new window to study inner Galactic globular clusters (GCs) using their variable stars. These GCs have been neglected in the past due to the difficulties caused by the presence of elevated extinction and high field stellar densities in their lines of sight. However, the discovery and study of any present variables in these clusters, especially RR Lyrae stars, can help to greatly improve the accuracy of their physical parameters. It can also help to shed some light on the questions raised by the intriguing Oosterhoff dichotomy in the Galactic GC system. In a series of papers we plan to explore variable stars in the GCs falling inside the field of the VVV survey. In this first paper, we search for and study the variables present in two highly reddened, moderately metal-poor, faint, inner Galactic GCs: 2MASS-GC 02 and Terzan 10. We report the discovery of sizable populations of RR Lyrae stars in both GCs. We use near-infrared period–luminosity relations to determine the color excess of each RR Lyrae star, from which we obtain both accurate distances to the GCs and the ratios of the selective-to-total extinction in their directions. We find the extinction toward both clusters to be elevated, non-standard, and highly differential. We also find both clusters to be closer to the Galactic center than previously thought, with Terzan 10 being on the far side of the Galactic bulge. Finally, we discuss their Oosterhoff properties, and conclude that both clusters stand out from the dichotomy followed by most Galactic GCs.

  3. Gas sampling system for a mass spectrometer

    DOEpatents

    Taylor, Charles E; Ladner, Edward P

    2003-12-30

    The present invention relates generally to a gas sampling system, and specifically to a gas sampling system for transporting a hazardous process gas to a remotely located mass spectrometer. The gas sampling system includes a capillary tube having a predetermined capillary length and capillary diameter in communication with the supply of process gas and the mass spectrometer, a flexible tube surrounding and coaxial with the capillary tube intermediate the supply of process gas and the mass spectrometer, a heat transfer tube surrounding and coaxial with the capillary tube, and a heating device in communication the heat transfer tube for substantially preventing condensation of the process gas within the capillary tube.

  4. 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.

  5. Spatial and temporal variability in distribution of water masses in Hornsund, Spitsbergen

    NASA Astrophysics Data System (ADS)

    Promińska, Agnieszka; Falck, Eva; Walczowski, Waldemar; Sundfjord, Arild

    2016-04-01

    Arctic fjords constitute an important part of many recent investigations because this is the place where different water masses meet, mix, and transform, influencing the stability of glaciers. Hornsund, the southernmost fjord of West Spitsbergen, has been studied during the past 15 years. Observations were based primarily on high resolution measurements of water temperature and salinity along fixed sections, that have been performed every July between 2001-2015. Research carried out in years 2010 - 2015 under Polish - Norwegian projects AWAKE and AWAKE-2 allowed for expansion of the database with data covering the period from spring to autumn. During this time measurements were also conducted from a small boat in the vicinity of glaciers with a time resolution of 1-2 weeks in addition to a mooring system deployed in the fjord and on the shelf just outside Hornsund. Synthesis of our measurements give an overview of water masses observed in the fjord. From summer to summer observations reveal high variability in water temperature and salinity giving a distinct division into an area influenced by oceanic factors (Main Basin) and an area which is more influenced by local factors (Brepollen). The chronology of water mass transformation has been obtained indicating a time of transition between winter (Arctic type), additionally interrupted by temporary inflow of waters of Atlantic origin, and summer (Atlantic type) conditions.

  6. Long-term optical variability of high-mass X-ray binaries. II. Spectroscopy

    NASA Astrophysics Data System (ADS)

    Reig, P.; Nersesian, A.; Zezas, A.; Gkouvelis, L.; Coe, M. J.

    2016-05-01

    Context. High-mass X-ray binaries are bright X-ray sources. The high-energy emission is caused by the accretion of matter from the massive companion onto a neutron star. The accreting material comes from either the strong stellar wind in binaries with supergiant companions or the cirscumstellar disk in Be/X-ray binaries. In either case, the Hα line stands out as the main source of information about the state of the accreting material. Aims: We present the results of our monitoring program to study the long-term variability of the Hα line in high-mass X-ray binaries. Our aim is to characterise the optical variability timescales and study the interaction between the neutron star and the accreting material. Methods: We fitted the Hα line with Gaussian profiles and obtained the line parameters and equivalent width. The peak separation in split profiles was used to determine the disk velocity law and estimate the disk radius. The relative intensity of the two peaks (V/R ratio) allowed us to investigate the distribution of gas particles in the disk. The equivalent width was used to characterise the degree of variability of the systems. We also studied the variability of the Hα line in correlation with the X-ray activity. Results: Our results can be summarised as follows: i) we find that Be/X-ray binaries with narrow orbits are more variable than systems with long orbital periods; ii) we show that a Keplerian distribution of gas particles provides a good description of the disks in Be/X-ray binaries, as it does in classical Be stars; iii) a decrease in the Hα equivalent width is generally observed after major X-ray outbursts; iv) we confirm that the Hα equivalent width correlates with disk radius; v) while systems with supergiant companions display multi-structured profiles, most of the Be/X-ray binaries show, at some epoch, double-peak asymmetric profiles, which indicates that density inhomogeneities is a common property in the disk of Be/X-ray binaries; vi) the

  7. Variable temperature seat climate control system

    DOEpatents

    Karunasiri, Tissa R.; Gallup, David F.; Noles, David R.; Gregory, Christian T.

    1997-05-06

    A temperature climate control system comprises a variable temperature seat, at least one heat pump, at least one heat pump temperature sensor, and a controller. Each heat pump comprises a number of Peltier thermoelectric modules for temperature conditioning the air in a main heat exchanger and a main exchanger fan for passing the conditioned air from the main exchanger to the variable temperature seat. The Peltier modules and each main fan may be manually adjusted via a control switch or a control signal. Additionally, the temperature climate control system may comprise a number of additional temperature sensors to monitor the temperature of the ambient air surrounding the occupant as well as the temperature of the conditioned air directed to the occupant. The controller is configured to automatically regulate the operation of the Peltier modules and/or each main fan according to a temperature climate control logic designed both to maximize occupant comfort during normal operation, and minimize possible equipment damage, occupant discomfort, or occupant injury in the event of a heat pump malfunction.

  8. Variable acuity remote viewing system flight demonstration

    NASA Technical Reports Server (NTRS)

    Fisher, R. W.

    1983-01-01

    The Variable Acuity Remote Viewing System (VARVS), originally developed under contract to the Navy (ONR) as a laboratory brassboard, was modified for flight demonstration. The VARVS system was originally conceived as a technique which could circumvent the acuity/field of view/bandwidth tradeoffs that exists in remote viewing to provide a nearly eye limited display in both field of view (160 deg) and resolution (2 min arc) while utilizing conventional TV sensing, transmission, and display equipment. The modifications for flight demonstration consisted of modifying the sensor so it could be installed and flow in a Piper PA20 aircraft, equipped for remote control and modifying the display equipment so it could be integrated with the NASA Research RPB (RPRV) remote control cockpit.

  9. Identifying climatic drivers of glacier mass balance variability of Lewis glacier, Mt. Kenya

    NASA Astrophysics Data System (ADS)

    Nicholson, Lindsey; Prinz, Rainer; Kaser, Georg

    2013-04-01

    Lewis Glacier (Kenya, 0°09' S; 37°18' E) has a 20 year historical annual mass balance record, spanning 1979-1996 and 2010-2012. This offers an opportunity to investigate the glacier-climate interactions at ~4800m a.s.l. in the equatorial zone, which in turn allows investigation of the possible tropical mid-tropospheric conditions that must have prevailed in order to permit formerly larger glacier extents on the mountain. Here we use field data of glacier annual mass balance, seasonal glacier surface height changes and monthly precipitation records to test the impact of potential drivers on the glacier variability. We examine relationships between these glaciological data and ERA-interim atmospheric fields, satellite measurements of outgoing long wave radiation and sea surface temperatures. In all years except the mass balance year of 1989 Lewis glacier experiences a negative mass balance. Strongly negative annual mass balances occur only if one or both of the wet seasons fail to bring snowfall to the summit and both annual mass balance and rainy season surface change is well correlated with measured precipitation and enhanced convection within the equatorial rain belt in East Africa and the western Indian Ocean. Seasonal glacier surface height change is correlated with air temperature throughout the whole tropical African zone during the dry months of January and February, but the only positive mass balance year experienced seasonal cold temperature anomalies over equatorial Africa in all seasons. No single season emerges as the dominant driver of the inter-annual mass balance variability, and the climate sensitivity of the glacier surface change differs between seasons. However Lewis Glacier mass balance over the study period can be explained by moisture variability as the primary driver and temperature variability as an additional driver of glacier mass change.

  10. An analysis of space power system masses

    NASA Technical Reports Server (NTRS)

    Kenny, Barbara H.; Cull, Ronald C.; Kankam, M. David

    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.

  11. Online mass storage system detailed requirements document

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The requirements for an online high density magnetic tape data storage system that can be implemented in a multipurpose, multihost environment is set forth. The objective of the mass storage system is to provide a facility for the compact storage of large quantities of data and to make this data accessible to computer systems with minimum operator handling. The results of a market survey and analysis of candidate vendor who presently market high density tape data storage systems are included.

  12. Comparative glacio-climatological analysis of mass balance variability along the geographical margin of Europe

    NASA Astrophysics Data System (ADS)

    Lehoczky, Annamária; Kern, Zoltán; Pongrácz, Rita

    2014-05-01

    Glacio-climatological studies recognise glacier mass balance changes as high-confident climate indicators. The climatic sensitivity of a glacier does not simply depend on regional climate variability but also influenced via large- and mesoscale atmospheric circulation patterns. This study focuses on recent changes in the mass balance using records from three border regions of Europe, and investigates the relationships between the seasonal mass balance components, regional climatic conditions, and distant atmospheric forcing. Since glaciers in different macro-climatological conditions (i.e., mid-latitudes or high-latitudes, dry-continental or maritime regions) may present strongly diverse mass balance characteristics, the three analysed regions were selected from different glacierised macroregions (using the database of the World Glacier Monitoring Service). These regions belong to the Caucasus Mountains (Central Europe macroregion), the Polar Ural (Northern Asia macroregion), and Svalbard (Arctic Islands macroregion). The analysis focuses on winter, summer, and annual mass balance series of eight glaciers. The climatic variables (atmospheric pressure, air temperature, precipitation) and indices of teleconnection patterns (e.g., North Atlantic Oscillation, Pacific Decadal Oscillation) are used from the gridded databases of the University of East Anglia, Climatic Research Unit and the National Oceanic and Atmospheric Administration, National Center for Environmental Prediction. However, the period and length of available mass balance data in the selected regions vary greatly (the first full record is in 1958, Polar Ural; the last is in 2010, Caucasus Mountains), a comparative analysis can be carried out for the period of 1968-1981. Since glaciers from different regions respond to large- and mesoscale climatic forcings differently, and because the mass balance of glaciers within a region often co-vary, our specific objectives are (i) to examine the variability and the

  13. Stability of libration points in the restricted four-body problem with variable mass

    NASA Astrophysics Data System (ADS)

    Mittal, Amit; Aggarwal, Rajiv; Suraj, Md. Sanam; Bisht, Virender Singh

    2016-10-01

    We have investigated the stability of the Lagrangian solutions for the restricted four-body problem with variable mass. It has been assumed that the three primaries with masses m1, m2 and m3 form an equilateral triangle, wherein m2=m3. According to Jeans' law (Astronomy and Cosmogony, Cambridge University Press, Cambridge, 1928), the infinitesimal body varies its mass m with time. The space-time transformations of Meshcherskii (Studies on the Mechanics of Bodies of Variable Mass, GITTL, Moscow, 1949) are used by taking the values of the parameters q=1/2, k=0, n=1. The equations of motion of the infinitesimal body with variable mass have been determined. The equations of motion of the current problem differ from the ones of the restricted four-body problem with constant mass. There exist eight libration points, out of which two are collinear with the primary m1 and the rest are non-collinear for a fixed value of parameters γ (m {at time} t/m {at initial time}, 0<γ≤1 ), α (the proportionality constant in Jeans' law (Astronomy and Cosmogony, Cambridge University Press, Cambridge, 1928), 0≤α≤2.2) and μ=0.019 (the mass parameter). All the libration points are found to be unstable. The zero velocity surfaces (ZVS) are also drawn and regions of motion are discussed.

  14. 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.

  15. 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.

  16. Alaska SAR Facility mass storage, current system

    NASA Technical Reports Server (NTRS)

    Cuddy, David; Chu, Eugene; Bicknell, Tom

    1993-01-01

    This paper examines the mass storage systems that are currently in place at the Alaska SAR Facility (SAF). The architecture of the facility will be presented including specifications of the mass storage media that are currently used and the performances that we have realized from the various media. The distribution formats and media are also discussed. Because the facility is expected to service future sensors, the new requirements and possible solutions to these requirements are also discussed.

  17. [The analysis of the causes of variability of the relationship between leaf dry mass and area in plants].

    PubMed

    Vasfilov, S P

    2011-01-01

    The lamina dry mass: area ratio (LMA - Leaf Mass per Area) is a quite variable trait. Leaf dry mass consists of symplast mass (a set of all leaf protoplasts) and apoplast mass (a set of all cell walls in a leaf). The ratio between symplast and apoplast masses is positively related to any functional trait of leaf calculated per unit of dry mass. The value of this ratio is defined by cells size and their number per unit of leaf area, number of mesophyll cells layers and their differentiation between palisade and spongy ones, and also by density of cells packing. The LMA value is defined by leaf thickness and density. The extent and direction of variability in both leaf traits define the extent and direction of variability in LMA. Negative correlation between leaf thickness and density reduces the level of LMA variability. As a consequence of this correlation the following pattern emerges: the thinner a leaf, the denser it is. Changes in the traits that define the LMA value take place both within a species under the influence of environmental factors and between species that differ in leaf structure and functions. Light is the most powerful environmental factor that influences the LMA, increase in illumination leading to increase in LMA. This effect occurs during leaf growth at the expense of structural changes associated with the reduction of symplast/apoplast mass ratio. Under conditions of intense illumination, LMA may increase due to accumulation of starch. With regard to the majority of leaf functions, the mass of starch may be ascribed to apoplast. Starch accumulation in leaves is observed also under conditions of elevated CO2 concentration in the air. Under high illumination, however, LMA increases also due to increased apoplast contribution to leaf dry mass. Scarce mineral nutrition leads to LMA increase due to lowering of growth zones demands for phothosyntates and, therefore, to increase in starch content of leaves. High level of mineral nutrition during

  18. Asymmetric EPR entanglement in continuous variable systems

    NASA Astrophysics Data System (ADS)

    Wagner, Katherine; Janousek, Jiri; Armstrong, Seiji; Morizur, Jean-François; Lam, Ping Koy; Bachor, Hans-Albert

    2014-11-01

    Continuous variable entanglement can be produced in nonlinear systems or via the interference of squeezed states. In many optical systems such as parametric down conversion, the production of two perfectly symmetric subsystems is usually assumed when demonstrating the existence of entanglement. This symmetry simplifies the description of entanglement. However, asymmetry in entanglement may arise naturally in a real experiment, or be intentionally introduced in a given quantum information protocol. These asymmetries can emerge from having the output beams experience different losses and environmental contamination, or from the availability of non-identical input quantum states in quantum communication protocols. In this paper, we present a visualization of entanglement using quadrature amplitude plots of the twin beams. We quantitatively discuss the strength of asymmetric entanglement using EPR and inseparability criteria and theoretically show that the optimal beamsplitter ratio for entanglement is dependent on the asymmetries and may not be 50 : 50. To support this theory, we present experimental results showing one particular asymmetric entanglement where a 78 : 22 beamsplitter is optimal for observing entanglement.

  19. INFRARED VARIABILITY OF THE GLIESE 569B SYSTEM

    SciTech Connect

    Kenworthy, Matthew A.; Scuderi, Louis J.

    2012-06-20

    Gliese 569B is a multiple brown dwarf system whose exact nature has been the subject of several investigations over the past few years. Interpretation has partially relied on infrared photometry and spectroscopy of the resolved components of the system. We present seeing-limited K{sub s} photometry over four nights, searching for variability in this young low-mass substellar system. Our photometry is consistent with other reported photometry, and we report the tentative detection of several periodic signals consistent with rotational modulation due to spots on their surfaces. The five significant periods range from 2.90 hr to 12.8 hr, with peak-to-peak variabilities from 28 mmag to 62 mmag in the K{sub s} band. If both components are rotating with the shortest periods, then their rotation axes are not parallel with each other, and the rotation axis of the Bb component is not perpendicular to the Ba-Bb orbital plane. If Bb has one of the longer rotational periods, then the Bb rotation axis is consistent with being parallel to the orbital axis of the Ba-Bb system.

  20. Control system for an infinitely variable transmission

    SciTech Connect

    Sakai, Y.

    1986-12-09

    This patent describes a control system for an infinitely variable belt-drive transmission having a selector device including a drive range position and a neutral position, a drive pulley having a hydraulically shiftable disc and a servo chamber for shifting the disc, and a driven pulley having a hydraulically shiftable disc and a servo chamber for shifting the disc. It also has a belt engaged with both the pulleys, a hydraulic control circuit for supplying oil to the servo chambers and for draining the servo chambers. The hydraulic control circuit is provided with a pressure regulator valve for providing a line pressure and a transmission ratio control valve for applying the line pressure to the servo chamber of the drive pulley. The improvement described here comprises: a lubricating oil circuit provided in the hydraulic control circuit for supplying lubricating oil to the drive and driven pulleys; a passage for supplying a part of the lubricating oil to the servo chamber of the drive pulley; a check valve provided in the passage for preventing the reverse flow of the lubricating oil; and a select position detecting valve for enabling the supply of the lubricating oil to the servo chamber at the selection of the neutral position.

  1. Control system for a continuously variable transmission

    SciTech Connect

    Sakai, Y.

    1987-11-03

    This patent describes a control system for a continuously variable belt-drive transmission having a selector device including a drive range position, a drive pulley having a hydraulically shiftable disc and a servo chamber for shifting the disc, a driven pulley having a hydraulically shiftable disc and a servo chamber for shifting the disc, and a belt engaged with both the pulleys, an hydraulic control circuit for supplying oil to the servo chambers and for draining the servo chambers, the hydraulic control circuit being provided with a pressure regulator valve for providing a line pressure and a transmission ratio control valve for applying the line pressure to the servo chamber of the drive pulley. The improvement comprises: a first drain passage from the pressure regulator valve; a second drain passage from the transmission ratio control valve; a first check valve provided in the first drain passage and a second check valve provided in the second drain passage for building up supplementary low pressure in both drain passages at upstream of both the check valves; a supplementary oil passage communicating both the first and second drain passages at upstream of the check valves for supplying a part of drain oil to the servo chamber of the drive pulley.

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

    NASA Astrophysics Data System (ADS)

    Toward, Martin G. R.; Griffin, Michael J.

    2011-02-01

    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 vertical apparent masses of 80 seated adults (41 males and 39 females aged 18-65) were measured at frequencies between 0.6 and 20 Hz with four backrest conditions (no backrest, upright rigid backrest, reclined rigid backrest, reclined foam backrest) and with three magnitudes of random vibration (0.5, 1.0 and 1.5 m s -2 rms). Relationships between subject physical characteristics (age, gender, weight, and anthropometry) and subject apparent mass were investigated with multiple regression models. The strongest predictor of the modulus of the vertical apparent mass at 0.6 Hz, at resonance, and at 12 Hz was body weight, with other factors having only a marginal effect. After correction for other variables, the principal resonance frequency was most consistently associated with age and body mass index. As age increased from 18 to 65 years, the resonance frequency increased by up to 1.7 Hz, and when the body mass index was increased from 18 to 34 kg m -2 the resonance frequency decreased by up to 1.7 Hz. These changes were greater than the 0.9-Hz increase in resonance frequency between sitting without a backrest and sitting with a reclined rigid backrest, and greater than the 1.0-Hz reduction in resonance frequency when the magnitude of vibration increased from 0.5 to 1.5 m s -2 rms. It is concluded that the effects of age, body mass index, posture, vibration magnitude, and weight should be taken into account when defining the vertical apparent mass of the seated human body.

  3. 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.

  4. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

    We present the first dynamical determination of the binary parameters of an eclipsing SW Sextantis star in the 3-4 h 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 Small & Moderate Aperture Research Telescope System, 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 ± 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 30 000 ± 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 M1 = 0.87 ± 0.09 M⊙ and M2 = 0.47 ± 0.05 M⊙ for the white dwarf and the M dwarf, respectively, and an inclination of the orbital plane of i ≈ 79°. A radius of 0.0103 ± 0.0007 R⊙ is obtained for the white dwarf. The secondary star in HS 0220+0603 is likely too cool and undersized for its mass.

  6. Effect of body mass and midsole hardness on kinetic and perceptual variables during basketball landing manoeuvres.

    PubMed

    Nin, Darren Z; Lam, Wing K; Kong, Pui W

    2016-01-01

    This study investigated the effects of body mass and shoe midsole hardness on kinetic and perceptual variables during the performance of three basketball movements: (1) the first and landing steps of layup, (2) shot-blocking landing and (3) drop landing. Thirty male basketball players, assigned into "heavy" (n = 15, mass 82.7 ± 4.3 kg) or "light" (n = 15, mass 63.1 ± 2.8 kg) groups, performed five trials of each movement in three identical shoes of varying midsole hardness (soft, medium, hard). Vertical ground reaction force (VGRF) during landing was sampled using multiple wooden-top force plates. Perceptual responses on five variables (forefoot cushioning, rearfoot cushioning, forefoot stability, rearfoot stability and overall comfort) were rated after each movement condition using a 150-mm Visual Analogue Scale (VAS). A mixed factorial analysis of variance (ANOVA) (Body Mass × Shoe) was applied to all kinetic and perceptual variables. During the first step of the layup, the loading rate associated with rearfoot contact was 40.7% higher in the "heavy" than "light" groups (P = .014) and 12.4% higher in hard compared with soft shoes (P = .011). Forefoot peak VGRF in a soft shoe was higher (P = .011) than in a hard shoe during shot-block landing. Both "heavy" and "light" groups preferred softer to harder shoes. Overall, body mass had little effect on kinetic or perceptual variables. PMID:26211423

  7. Effect of body mass and midsole hardness on kinetic and perceptual variables during basketball landing manoeuvres.

    PubMed

    Nin, Darren Z; Lam, Wing K; Kong, Pui W

    2016-01-01

    This study investigated the effects of body mass and shoe midsole hardness on kinetic and perceptual variables during the performance of three basketball movements: (1) the first and landing steps of layup, (2) shot-blocking landing and (3) drop landing. Thirty male basketball players, assigned into "heavy" (n = 15, mass 82.7 ± 4.3 kg) or "light" (n = 15, mass 63.1 ± 2.8 kg) groups, performed five trials of each movement in three identical shoes of varying midsole hardness (soft, medium, hard). Vertical ground reaction force (VGRF) during landing was sampled using multiple wooden-top force plates. Perceptual responses on five variables (forefoot cushioning, rearfoot cushioning, forefoot stability, rearfoot stability and overall comfort) were rated after each movement condition using a 150-mm Visual Analogue Scale (VAS). A mixed factorial analysis of variance (ANOVA) (Body Mass × Shoe) was applied to all kinetic and perceptual variables. During the first step of the layup, the loading rate associated with rearfoot contact was 40.7% higher in the "heavy" than "light" groups (P = .014) and 12.4% higher in hard compared with soft shoes (P = .011). Forefoot peak VGRF in a soft shoe was higher (P = .011) than in a hard shoe during shot-block landing. Both "heavy" and "light" groups preferred softer to harder shoes. Overall, body mass had little effect on kinetic or perceptual variables.

  8. 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.

  9. Linking the spatial variability of glacier mass loss to fjord geometry

    NASA Astrophysics Data System (ADS)

    Porter, D. F.; Tinto, K. J.; Boghosian, A.; Cochran, J. R.; Csatho, B. M.; Bell, R. E.

    2015-12-01

    There is compelling evidence of increasing mass loss of the ice sheets using a diverse set of observations, including increased thinning rates measured from both airborne and satellite altimeters, elevated mass fluxes resulting from the acceleration of outlet glaciers, and mass changes measured directly from satellite gravimetry. A dominant characteristic of observed change in Greenland outlet glaciers is that it is locally random. Numerous studies have revealed a high degree of spatial and temporal variability of outlet glacier mass change. Modeling studies suggest that increased ocean temperatures may be responsible for the observed glacial retreat in Greenland through increased basal melting, leading to increased calving rates, terminus retreat, glacier speedup, and eventually thinning of inland ice. Knowledge of fjord geometry is crucial for ice-ocean interaction because the availability of ocean heat to the ice will be restricted by narrow sills and shallow grounding lines. We investigate whether the variability in observed changes among Greenland glaciers can be partially explained by variation in fjord geometry. Using statistical techniques commonly employed to detect patterns in complex spatial data, we objectively show that mass change in Greenland tidewater glaciers between 2003 and 2009 is indeed mostly spatially incoherent. Except for a few clusters of similar change in the NW and Scoresby Sund regions, there is significant glacier-scale variability in mass loss rates. To understand the drivers of this local variability, we compare fjord bathymetries from all regions of Greenland, modeled using airborne gravimetry measurements from NASA Operation IceBridge flights, to estimates of glaciological change. Specifically, we investigate the correlation between water depths at the grounding line and the dynamic mass loss of tidewater glaciers. In theory, a deep grounding line will allow greater interaction with the warm Atlantic Water observed in most fjords

  10. Expert overseer for mass spectrometer system

    DOEpatents

    Filby, Evan E.; Rankin, Richard A.

    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.

  11. Effective mass discontinuity and current oscillations in stratified systems

    NASA Astrophysics Data System (ADS)

    Halilov, S.; Mil'shtein, S.

    2015-11-01

    Tunnelling transport in modulated film, which occurs either stoichiometrically or due to a stress field, is analysed in terms of the variable carrier effective mass tensor. It is shown that the mass tensor discontinuity alone, i.e. with no actual potential barrier present, may lead to current oscillations versus the size of the modulated region. While both effects of mass discontinuity and the band offset upon the carrier flow are formally described in terms of wave mechanics, their mechanisms are quite distinct: the magnitude of the current oscillations due to mass disruption is determined by the differential mass across the interface, i.e. by change in the covalency due to structural modulation, whereas the band offset is generally an effect of the affinity change across the interface. Both effects are superimposed by the 3D kinematic coupling of the orthogonal transport, either constructively or destructively, leading to an oscillatory dependence of the current magnitude on the film dimension. As an illustration, the analysis is applied to a Si1-x Ge x /Si stratified structure to demonstrate the effect of quasi-bound states on the transport. The modelling is corroborated by a device simulation of a SiGe system in a heterojunction bipolar transistor setting. The findings can be used as a general method to control anisotropic tunnelling transport in stratified structures.

  12. A fully mass conservative variable parameter McCarthy-Muskingum method: Theory and verification

    NASA Astrophysics Data System (ADS)

    Perumal, Muthiah; Price, Roland K.

    2013-10-01

    This paper presents the hydraulic derivation of a fully mass conservative, variable parameter McCarthy-Muskingum (VPMM) method derived directly from the Saint-Venant equations for routing flood waves in prismatic channels having any cross-section shape, and using the Manning's friction law. The approach employed in the development of the method theoretically justifies the heuristic assumption made by McCarthy in 1938 in expressing the channel reach storage of the Muskingum method in terms of prism and wedge storages. The approach advocated in this paper also provides a solution to the mass conservation problem associated with the variable parameter Muskingum routing method, which has been a major issue in the hydrological literature for the last three decades. Moreover, the VPMM method enables the simultaneous computation of the stage hydrograph corresponding to a given inflow or routed discharge hydrograph. The verification of the methodology and the evaluation of its performance in routing floods in three different shapes of a hypothetical channels are presented by reproducing the corresponding numerical solutions of the Saint-Venant equations. The results are also compared with the corresponding results of the mass conservative variable parameter Muskingum-Cunge-Todini method proposed by Todini in 2007 with and without the inclusion of the correction introduced by Cappelaere in 1997 for diffusion.

  13. 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.

  14. Mass spectrometer vacuum housing and pumping system

    DOEpatents

    Coutts, Gerald W.; Bushman, John F.; Alger, Terry W.

    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.

  15. 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).

  16. Stellar modelling of Spica, a high-mass spectroscopic binary with a β Cep variable primary component

    NASA Astrophysics Data System (ADS)

    Tkachenko, A.; Matthews, J. M.; Aerts, C.; Pavlovski, K.; Pápics, P. I.; Zwintz, K.; Cameron, C.; Walker, G. A. H.; Kuschnig, R.; Degroote, P.; Debosscher, J.; Moravveji, E.; Kolbas, V.; Guenther, D. B.; Moffat, A. F. J.; Rowe, J. F.; Rucinski, S. M.; Sasselov, D.; Weiss, W. W.

    2016-05-01

    Binary stars provide a valuable test of stellar structure and evolution, because the masses of the individual stellar components can be derived with high accuracy and in a model-independent way. In this work, we study Spica, an eccentric double-lined spectroscopic binary system with a β Cep type variable primary component. We use state-of-the-art modelling tools to determine accurate orbital elements of the binary system and atmospheric parameters of both stellar components. We interpret the short-period variability intrinsic to the primary component, detected on top of the orbital motion both in the photometric and spectroscopic data. The non-local thermodynamic equilibrium based spectrum analysis reveals two stars of similar atmospheric chemical composition consistent with the present-day cosmic abundance standard. The masses and radii of the stars are found to be 11.43 ± 1.15 M⊙ and 7.21 ± 0.75 M⊙, and 7.47 ± 0.54 R⊙ and 3.74 ± 0.53 R⊙ for the primary and secondary, respectively. We find the primary component to pulsate in three independent modes, of which one is identified as a radial mode, while the two others are found to be non-radial, low degree l modes. The frequency of one of these modes is an exact multiple of the orbital frequency, and the l = m = 2 mode identification suggests a tidal nature for this particular mode. We find a very good agreement between the derived dynamical and evolutionary masses for the Spica system to within the observational errors of the measured masses. The age of the system is estimated to be 12.5 ± 1 Myr.

  17. Mass and Reliability System (MaRS)

    NASA Technical Reports Server (NTRS)

    Barnes, Sarah

    2016-01-01

    The Safety and Mission Assurance (S&MA) Directorate is responsible for mitigating risk, providing system safety, and lowering risk for space programs from ground to space. The S&MA is divided into 4 divisions: The Space Exploration Division (NC), the International Space Station Division (NE), the Safety & Test Operations Division (NS), and the Quality and Flight Equipment Division (NT). The interns, myself and Arun Aruljothi, will be working with the Risk & Reliability Analysis Branch under the NC Division's. The mission of this division is to identify, characterize, diminish, and communicate risk by implementing an efficient and effective assurance model. The team utilizes Reliability and Maintainability (R&M) and Probabilistic Risk Assessment (PRA) to ensure decisions concerning risks are informed, vehicles are safe and reliable, and program/project requirements are realistic and realized. This project pertains to the Orion mission, so it is geared toward a long duration Human Space Flight Program(s). For space missions, payload is a critical concept; balancing what hardware can be replaced by components verse by Orbital Replacement Units (ORU) or subassemblies is key. For this effort a database was created that combines mass and reliability data, called Mass and Reliability System or MaRS. The U.S. International Space Station (ISS) components are used as reference parts in the MaRS database. Using ISS components as a platform is beneficial because of the historical context and the environment similarities to a space flight mission. MaRS uses a combination of systems: International Space Station PART for failure data, Vehicle Master Database (VMDB) for ORU & components, Maintenance & Analysis Data Set (MADS) for operation hours and other pertinent data, & Hardware History Retrieval System (HHRS) for unit weights. MaRS is populated using a Visual Basic Application. Once populated, the excel spreadsheet is comprised of information on ISS components including

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

    SciTech Connect

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

    2009-03-16

    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 converter 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 Conductance Heat Pipe (VCHP) is under development to allow multiple stops and restarts of the Stirling engine. 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 deg. C while the heat losses caused by the addition of the VCHP are 1.8 W.

  19. A New Sample of Candidate Intermediate-mass Black Holes Selected by X-Ray Variability

    NASA Astrophysics Data System (ADS)

    Kamizasa, Naoya; Terashima, Yuichi; Awaki, Hisamitsu

    2012-05-01

    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) × 106 M ⊙ by using a correlation between excess variance and BH mass. Seven sources have estimated BH masses smaller than 2 × 106 M ⊙, 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 ≈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 ≈ 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. Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA.

  20. LMI-based controller design for dynamic variable structure systems

    NASA Astrophysics Data System (ADS)

    Ohtake, Hiroshi; Tanaka, Kazuo

    2005-12-01

    This paper presents controller design conditions for dynamic variable structure systems in terms of linear matrix inequalities (LMIs). In our previous paper, we proposed the dynamic variable structure system and derived its controller design conditions using switching fuzzy model-based control approach. However, the controller design conditions were given in terms of bilinear matrix inequalities (BMIs). In this paper, by introducing the augmented system which consists of the switching fuzzy model and a stable linear system, we derive new controller design conditions in terms of linear matrix inequalities (LMIs) for the dynamic variable structure systems. A simulation result shows the utility of this control approach.

  1. Advective-diffusive mass transfer in fractured porous media with variable rock matrix block size.

    PubMed

    Sharifi Haddad, Amin; Hassanzadeh, Hassan; Abedi, Jalal

    2012-05-15

    Traditional dual porosity models do not take into account the effect of matrix block size distribution on the mass transfer between matrix and fracture. In this study, we introduce the matrix block size distributions into an advective-diffusive solute transport model of a divergent radial system to evaluate the mass transfer shape factor, which is considered as a first-order exchange coefficient between the fracture and matrix. The results obtained lead to a better understanding of the advective-diffusive mass transport in fractured porous media by identifying two early and late time periods of mass transfer. Results show that fractured rock matrix block size distribution has a great impact on mass transfer during early time period. In addition, two dimensionless shape factors are obtained for the late time, which depend on the injection flow rate and the distance of the rock matrix from the injection point.

  2. Promoting physician productivity through a variable compensation system.

    PubMed

    Hickey, M; Ichter, J T

    1997-08-01

    Integrated delivery systems must find ways to achieve optimal physician productivity and accountability, while fostering an entrepreneurial attitude among physicians. Lovelace Health Systems, Albuquerque, New Mexico, has implemented a variable compensation system designed for this purpose. An assessment of Lovelace's physician productivity had indicated performance well below national medians. To offer physicians a strong incentive to increase productivity, Lovelace developed a variable compensation system based on the resource-based relative value scale and relative value units. Lovelace also developed benchmark productivity targets.

  3. Variability in young very low mass stars: two surprises from spectrophotometric monitoring

    NASA Astrophysics Data System (ADS)

    Bozhinova, I.; Scholz, A.; Eislöffel, J.

    2016-05-01

    We present simultaneous photometric and spectroscopic observations of seven young and highly variable M dwarfs in star-forming regions in Orion, conducted in four observing nights with FOcal Reducer and low dispersion Spectrograph2 at European Southern Observatory/VLT. All seven targets show significant photometric variability in the I band, with amplitudes between 0.1-0.8 mag, The spectra, however, remain remarkably constant, with spectral type changes less than 0.5 subtypes. Thus, the brightness changes are not caused by veiling that `fills in' absorption features. Three objects in the σ Ori cluster (age ˜3 Myr) exhibit strong Hα emission and Hα variability, in addition to the continuum variations. Their behaviour is mostly consistent with the presence of spots with temperature of ˜300 K above the photosphere and filling factors between 0.2-0.4, in contrast to typical hotspots observed in more massive stars. The remaining targets near ɛ Ori, likely to be older, show eclipse-like light curves, no significant Hα activity and are better represented by variable extinction due to circumstellar material. Interestingly, two of them show no evidence of infrared excess emission. Our study shows that high-amplitude variability in young very low mass stars can be caused by different phenomena than in more massive T Tauri stars and can persist when the disc has disappeared and accretion has ceased.

  4. Studies of Long Period Variability in Neutron Star HMXB Systems

    NASA Technical Reports Server (NTRS)

    Heindl, William A.

    1998-01-01

    The purpose of this effort was to investigate the long term, quasi-periodic variability of the X-ray emission from the accreting X-ray pulsars LMC X-4 and SMC X-1. These high mass X-ray binary (HMXB) sources are known to vary in a nearly periodic fashion with cycle lengths of about 30 and 60 days respectively. The prevailing model for such behavior is that it is due to the precession of a tilted accretion disk around the neutron star which is the source of the X-ray emission. As the disk precesses, it periodically obscures the emitting region, resulting in reduced flux as observed at the Earth. The obscuration is not strictly periodic, as the disk precession period changes as the total mass and size of the disk change through variable accretion processes. This model is well established for the long-period variability in the X-ray pulsar Her X-1. With this work, my collaborators and I sought to test whether this model works for LMC X-4 and SMC X-1. Observations with the pointed instruments on the Rossi X-ray Timing Explorer (RXTE) were carried out in order to observe changes in the X-ray spectrum and total flux which were correlated with the long period cycles in these objects. One of the main predictions of the precessing disk model is that the periods of low emission are caused not by changes in the central source, but by increased absorption of that flux as seen at the Earth. Such behavior would be observed in the X-ray spectrum as a relative lack of low energy X-rays (which are more easily absorbed) as compared to high energy X-rays. This is what was observed for SMC X-1, landing strong support to the precessing disk model for this system. For LMC X-1, however, the absorption was consistent with zero at the time of minimum flux. The entire spectrum appeared to be equally reduced. This is not supporting evidence for the model. However, it also does not rule out a precessing disk. If at the time of minimum flux, the intervening disk is so thick that no flux, even

  5. Surface Time-Variable Gravity Signals and Possible Sources Including Core Mass Flow

    NASA Technical Reports Server (NTRS)

    Chao, Benjamin F.; Kuang, Weijia

    2003-01-01

    Over two decades of geodetic satellite-laser-ranging (SLR) data show that the variation of the Earth's oblateness parameter J2 has a clear seasonal signal of amplitude of about 3e-10 and a secular decrease of about -2.8e-11/year, superimposed on some interesting interannual fluctuations. Physically, any change in mass distribution or/inside the Earth will be reflected in the time-variable gravity signal obtained outside the Earth, according to Newton s gravitational law. Therefore, such signal contains contributions from all geophysical sources that redistribute mass, on all temporal and spatial scales, including those from the core. Besides Earth rotation and geomagnetic field variations, the time-variable gravity also contains information linking Earth surface observations with internal core dynamical processes. The time scales of the gravity signal are critical in helping differentiate different contributions. The atmosphere and hydrosphere are responsible for the seasonal and much of the interannual and intraseasoanl fluctuations, while the secular trend is due mainly to the post-glacial rebound but possibly core mass flow. To estimate the latter effect, we use our MoSST (Modular, Scalable, Self-consistent, Three-dimensional) core dynamics model to forward simulate the core flow, and density variation due to the core convection. Our results suggest that, when upward continued to the surface, the J2 component of the core mass redistribution can reach an overall amplitude of e-11/year, approaching the SLR detectability and significant in geophysical terms. We also find a general westward drift of the mass flow, with a speed comparable to that of the geomagnetic westward drift.

  6. Greenland Ice Sheet seasonal and spatial mass variability from model simulations and GRACE (2003-2012)

    NASA Astrophysics Data System (ADS)

    Alexander, Patrick M.; Tedesco, Marco; Schlegel, Nicole-Jeanne; Luthcke, Scott B.; Fettweis, Xavier; Larour, Eric

    2016-06-01

    Improving the ability of regional climate models (RCMs) and ice sheet models (ISMs) to simulate spatiotemporal variations in the mass of the Greenland Ice Sheet (GrIS) is crucial for prediction of future sea level rise. While several studies have examined recent trends in GrIS mass loss, studies focusing on mass variations at sub-annual and sub-basin-wide scales are still lacking. At these scales, processes responsible for mass change are less well understood and modeled, and could potentially play an important role in future GrIS mass change. Here, we examine spatiotemporal variations in mass over the GrIS derived from the Gravity Recovery and Climate Experiment (GRACE) satellites for the January 2003-December 2012 period using a "mascon" approach, with a nominal spatial resolution of 100 km, and a temporal resolution of 10 days. We compare GRACE-estimated mass variations against those simulated by the Modèle Atmosphérique Régionale (MAR) RCM and the Ice Sheet System Model (ISSM). In order to properly compare spatial and temporal variations in GrIS mass from GRACE with model outputs, we find it necessary to spatially and temporally filter model results to reproduce leakage of mass inherent in the GRACE solution. Both modeled and satellite-derived results point to a decline (of -178.9 ± 4.4 and -239.4 ± 7.7 Gt yr-1 respectively) in GrIS mass over the period examined, but the models appear to underestimate the rate of mass loss, especially in areas below 2000 m in elevation, where the majority of recent GrIS mass loss is occurring. On an ice-sheet-wide scale, the timing of the modeled seasonal cycle of cumulative mass (driven by summer mass loss) agrees with the GRACE-derived seasonal cycle, within limits of uncertainty from the GRACE solution. However, on sub-ice-sheet-wide scales, some areas exhibit significant differences in the timing of peaks in the annual cycle of mass change. At these scales, model biases, or processes not accounted for by models related

  7. Has Natural Variability Masked the Expected Increase in Antarctic Surface Mass Balance with Global Warming?

    NASA Astrophysics Data System (ADS)

    Previdi, M. J.; Polvani, L. M.

    2015-12-01

    One of the expected and rather paradoxical consequences of anthropogenic global warming is an increase in Antarctic surface mass balance (or net snow accumulation), as robustly simulated by both global and regional climate models. This surface mass balance (SMB) increase occurs because the higher moisture content of a warmer atmosphere leads to increases in precipitation, with this precipitation falling in the form of snow over Antarctica. Despite these robust model projections, however, observations indicate that there has been no significant change in Antarctic SMB during the past several decades. Here, we show that this apparent discrepancy between models and observations can be explained by the fact that the anthropogenic climate change signal is still relatively small compared to the noise associated with natural climate variability. Using an ensemble of 35 global coupled climate models to separate signal and noise, we find that the forced SMB increase due to global warming in recent decades is unlikely to be detectable in a statistical sense as a result of large natural SMB variability on interannual-to-multidecadal timescales. However, our analysis reveals that if the world continues to follow the present trajectory of greenhouse gas emissions, the anthropogenic impact on Antarctic SMB will emerge from natural variability by the middle of the current century. With this, SMB increases over Antarctica will begin to mitigate global sea-level rise, partially offsetting the effects of dynamic ice loss.

  8. Has Natural Variability Masked the Expected Increase in Antarctic Surface Mass Balance with Global Warming?

    NASA Astrophysics Data System (ADS)

    Previdi, Michael; Polvani, Lorenzo M.

    2016-04-01

    One of the expected and rather paradoxical consequences of anthropogenic global warming is an increase in Antarctic surface mass balance (or net snow accumulation), as robustly simulated by both global and regional climate models. This surface mass balance (SMB) increase occurs because the higher moisture content of a warmer atmosphere leads to increases in precipitation, with this precipitation falling in the form of snow over Antarctica. Despite these robust model projections, however, observations indicate that there has been no significant change in Antarctic SMB during the past several decades. Here, we show that this apparent discrepancy between models and observations can be explained by the fact that the anthropogenic climate change signal is still relatively small compared to the noise associated with natural climate variability. Using an ensemble of 35 global coupled climate models to separate signal and noise, we find that the forced SMB increase due to global warming in recent decades is unlikely to be detectable in a statistical sense as a result of large natural SMB variability on interannual-to-multidecadal timescales. However, our analysis reveals that if the world continues to follow the present trajectory of greenhouse gas emissions, the anthropogenic impact on Antarctic SMB will emerge from natural variability by the middle of the current century. With this, SMB increases over Antarctica will begin to mitigate global sea-level rise, partially offsetting the effects of dynamic ice loss.

  9. Variable Conductance Heat Pipes for Radioisotope Stirling Systems

    NASA Technical Reports Server (NTRS)

    Anderson, William G.; Tarau, Calin

    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 Conductance Heat Pipe (VCHP) was designed to allow multiple stops and restarts of the Stirling engine. A VCHP turns on with a delta T of 30 C, which is high enough to not risk standard ASRG operation but low enough to save most heater head life. This VCHP has a low mass, and low thermal losses for normal operation. In addition to the design, a proof-of-concept NaK VCHP was fabricated and tested. While NaK is normally not used in heat pipes, it has an advantage in that it is liquid at the reservoir operating temperature, while Na or K alone would freeze. The VCHP had two condensers, one simulating the heater head, and the other simulating the radiator. The experiments successfully demonstrated operation with the simulated heater head condenser off and on, while allowing the reservoir temperature to vary over 40 to 120 C, the maximum range expected. In agreement with previous NaK heat pipe tests, the evaporator delta T was roughly 70 C, due to distillation of the NaK in the evaporator.

  10. 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.

  11. Variable zoom system with aberration correction capability

    NASA Astrophysics Data System (ADS)

    Lu, Yang; Stockbridge, Christopher R.; Hoffman, Samuel M.; Bifano, Thomas G.

    2012-07-01

    We describe experiments conducted with two deformable mirrors (DMs) at fixed locations in an optical microscope imaging system. In this configuration, the DM shapes are controlled to provide 2.5× zoom capability, to allow dynamic focus control and to compensate for aberrations of the fixed optical components. Zoom is achieved by simultaneously adjusting focal lengths of the two DMs, which are inserted between an infinity-corrected microscope objective and a tube lens. Image quality is measured using contrast modulation, and performance of the system is quantified, demonstrating an improved point spread function in the adaptively compensated system.

  12. Variable emissivity laser thermal control system

    DOEpatents

    Milner, Joseph R.

    1994-01-01

    A laser thermal control system for a metal vapor laser maintains the wall mperature of the laser at a desired level by changing the effective emissivity of the water cooling jacket. This capability increases the overall efficiency of the laser.

  13. A variable-collimation display system

    NASA Astrophysics Data System (ADS)

    Batchko, Robert; Robinson, Sam; Schmidt, Jack; Graniela, Benito

    2014-03-01

    Two important human depth cues are accommodation and vergence. Normally, the eyes accommodate and converge or diverge in tandem; changes in viewing distance cause the eyes to simultaneously adjust both focus and orientation. However, ambiguity between accommodation and vergence cues is a well-known limitation in many stereoscopic display technologies. This limitation also arises in state-of-the-art full-flight simulator displays. In current full-flight simulators, the out-the-window (OTW) display (i.e., the front cockpit window display) employs a fixed collimated display technology which allows the pilot and copilot to perceive the OTW training scene without angular errors or distortions; however, accommodation and vergence cues are limited to fixed ranges (e.g., ~ 20 m). While this approach works well for long-range, the ambiguity of depth cues at shorter range hinders the pilot's ability to gauge distances in critical maneuvers such as vertical take-off and landing (VTOL). This is the first in a series of papers on a novel, variable-collimation display (VCD) technology that is being developed under NAVY SBIR Topic N121-041 funding. The proposed VCD will integrate with rotary-wing and vertical take-off and landing simulators and provide accurate accommodation and vergence cues for distances ranging from approximately 3 m outside the chin window to ~ 20 m. A display that offers dynamic accommodation and vergence could improve pilot safety and training, and impact other applications presently limited by lack of these depth cues.

  14. Control system for a continuously variable transmission

    SciTech Connect

    Vahabzadeh, H.

    1986-08-26

    A hydraulic control is described for a continuously variable transmission having hydraulically adjustable axially movable pulley members and a gearing arrangement for the transmitting of torque between an input shaft and a output shaft. The control consists of: a source of fluid pressure; first valve means connected with the source and being operable to supply control fluid to one of the first valve means to impose a force thereon; feedback means for imposing a force proportional to the axial position of the one adjustable pulley member on the first valve means in addition to the control fluid imposed force; torque sensing means operatively connected with the gearing arrangement for transmitting a force proportional to the torque transmitted by the gearing arrangement; servo motor means operatively connected with the torque sensing means; second valve means connected with the torque sensing means and being operable on a change of torque transmission to distribute a pressure signal from the source to the servo motor means and the servo motor means being responsive to the pressure fluid to balance the force on the torque to balance the force on the torque sensing means and discontinue fluid distribution thereto; and means for directing the pressure signal from the second valve means to the first valve means.

  15. 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, Ayşe; 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

  16. 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, Ayşe; 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.

  17. Mass balance and streamflow variability at Place Glacier, Canada, in relation to recent climate fluctuations

    NASA Astrophysics Data System (ADS)

    Moore, R. D.; Demuth, M. N.

    2001-12-01

    Although a great deal of research has focused on the hydrologic effects of climate variability and change, relatively little research has examined the effects on streamflow of interactions between climate variability and change and resulting glacier response. Place Glacier, in the southern Coast Mountains of British Columbia, Canada, has been monitored for mass balance since 1965, and a stream gauge was operated just below the glacier terminus from 1969 to 1989. This paper presents analyses of the mass balance history and streamflow variations in relation to recorded climatic variability.Place Glacier's winter and net balances are correlated with the Pacific Decadal Oscillation (PDO). Summer balance is positively correlated with summer temperature and negatively with the preceding winter balance, which enhances the effects of changes in winter balance on net balance. The well-documented post-1976 shift from the PDO cold phase to the present warm phase initiated a significant and persistent period of more negative net balance and terminal retreat. A reconstruction of net balance extending back to the 1890s, based on a regression with winter precipitation and summer temperature, displays decadal-scale fluctuations consistent with the PDO. Summer streamflow responded to interannual variations in winter snow accumulation and summer temperatures, which control the rate of rise of the glacier snowline and melt rates. After accounting for these influences via regression analysis, August streamflow displayed a negative trend in total runoff. Examination of air photographs and the reconstructed mass balance history suggest that significant firn depletion had occurred prior to 1965, such that the dominant effect of glacier changes was a reduction in ice area, resulting in decreased meltwater production.

  18. Variability and mass loss in IA O-B-A supergiants

    NASA Technical Reports Server (NTRS)

    Schild, R. E.; Garrison, R. F.; Hiltner, W. A.

    1983-01-01

    Recently completed catalogs of MK spectral types and UBV photometry of 1227 OB stars in the southern Milky Way have been analyzed to investigate brightness and color variability among the Ia supergiants. It is found that brightness variability is common among the O9-B1 supergiants with typical amplitudes about 0.1 and time scales longer than a week and shorter than 1000 days. Among the A supergiants fluctuations in U-B color are found on similar time scales and with amplitude about 0.1. For many early Ia supergiants there is a poor correlation between Balmer jump and spectral type, as had been known previously. An attempt to correlate the Balmer jump deficiency with mass loss rate yielded uncertain results.

  19. Southern Hemisphere water mass conversion linked with North Atlantic climate variability.

    PubMed

    Pahnke, Katharina; Zahn, Rainer

    2005-03-18

    Intermediate water variability at multicentennial scales is documented by 340,000-year-long isotope time series from bottom-dwelling foraminifers at a mid-depth core site in the southwest Pacific. Periods of sudden increases in intermediate water production are linked with transient Southern Hemisphere warm episodes, which implies direct control of climate warming on intermediate water conversion at high southern latitudes. Coincidence with episodes of climate cooling and minimum or halted deepwater convection in the North Atlantic provides striking evidence for interdependence of water mass conversion in both hemispheres, with implications for interhemispheric forcing of ocean thermohaline circulation and climate instability.

  20. Southern Hemisphere water mass conversion linked with North Atlantic climate variability.

    PubMed

    Pahnke, Katharina; Zahn, Rainer

    2005-03-18

    Intermediate water variability at multicentennial scales is documented by 340,000-year-long isotope time series from bottom-dwelling foraminifers at a mid-depth core site in the southwest Pacific. Periods of sudden increases in intermediate water production are linked with transient Southern Hemisphere warm episodes, which implies direct control of climate warming on intermediate water conversion at high southern latitudes. Coincidence with episodes of climate cooling and minimum or halted deepwater convection in the North Atlantic provides striking evidence for interdependence of water mass conversion in both hemispheres, with implications for interhemispheric forcing of ocean thermohaline circulation and climate instability. PMID:15774752

  1. Variable emissivity laser thermal control system

    DOEpatents

    Milner, J.R.

    1994-10-25

    A laser thermal control system for a metal vapor laser maintains the wall temperature of the laser at a desired level by changing the effective emissivity of the water cooling jacket. This capability increases the overall efficiency of the laser. 8 figs.

  2. Error response test system and method using test mask variable

    NASA Technical Reports Server (NTRS)

    Gender, Thomas K. (Inventor)

    2006-01-01

    An error response test system and method with increased functionality and improved performance is provided. The error response test system provides the ability to inject errors into the application under test to test the error response of the application under test in an automated and efficient manner. The error response system injects errors into the application through a test mask variable. The test mask variable is added to the application under test. During normal operation, the test mask variable is set to allow the application under test to operate normally. During testing, the error response test system can change the test mask variable to introduce an error into the application under test. The error response system can then monitor the application under test to determine whether the application has the correct response to the error.

  3. Applications of internal translating mass technologies to smart weapons systems

    NASA Astrophysics Data System (ADS)

    Rogers, Jonathan

    The field of guided projectile research has continually grown over the past several decades. Guided projectiles, typically encompassing bullets, mortars, and artillery shells, incorporate some sort of guidance and control mechanism to generate trajectory alterations. This serves to increase accuracy and decrease collateral damage. Control mechanisms for smart weapons must be able to withstand extreme acceleration loads at launch while remaining simple to reduce cost and enhance reliability. Controllable internal moving masses can be incorporated into the design of smart weapons as a mechanism to directly apply control force, to actively alter static stability in flight, and to protect sensitive components within sensor packages. This dissertation examined techniques for using internal translating masses (ITM's) for smart weapon flight control. It was first shown that oscillating a mass orthogonal to the projectile axis of symmetry generates reasonable control force in statically-stable rounds. Trade studies examined the impact of mass size, mass offset from the center of gravity, and reductions in static stability on control authority. A more detailed analysis followed in which a physical internal translating mass control mechanism was designed that minimizes force and power required using a vibrating beam as the internal moving mass. Results showed that this relatively simple mechanism provides adequate control authority while requiring low on-board power. Trade studies revealed the affect of varying beam lengths, stiffness, and damping properties. Then, the topic of static margin control through mass center modification was explored. This is accomplished by translating a mass in flight along the projectile axis of symmetry. Results showed that this system allows for greater control authority and reduced throw-off error at launch. Finally, a nonlinear sliding mode controller was designed for a projectile equipped with an internal moving mass as well as for a

  4. 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).

  5. Variability in Second Language Development from a Dynamic Systems Perspective

    ERIC Educational Resources Information Center

    Verspoor, Marjolijn; Lowie, Wander; Van Dijk, Marijn

    2008-01-01

    This article illustrates that studying intra-individual variability in Second Language Development can provide insight into the developmental dynamics of second language (L2) learners. Adopting a Dynamic Systems Theory framework (Thelen & Smith, 1994; van Geert, 1994) and using insights from microgenetic variability studies in developmental…

  6. Modeling the Motion of an Increasing Mass System

    ERIC Educational Resources Information Center

    Kunkel, William; Harrington, Randal

    2010-01-01

    Problems on the dynamics of changing mass systems often call for the more general form of Newton's second law Fnet = dp/dt. These problems usually involve situations where the mass of the system decreases, such as in rocket propulsion. In contrast, this experiment examines a system where the mass "increases" at a constant rate and the net force…

  7. Holonomic Quantum Control with Continuous Variable Systems

    NASA Astrophysics Data System (ADS)

    Albert, Victor V.; Shu, Chi; Krastanov, Stefan; Shen, Chao; Liu, Ren-Bao; Yang, Zhen-Biao; Schoelkopf, Robert J.; Mirrahimi, Mazyar; Devoret, Michel H.; Jiang, Liang

    2016-04-01

    Universal computation of a quantum system consisting of superpositions of well-separated coherent states of multiple harmonic oscillators can be achieved by three families of adiabatic holonomic gates. The first gate consists of moving a coherent state around a closed path in phase space, resulting in a relative Berry phase between that state and the other states. The second gate consists of "colliding" two coherent states of the same oscillator, resulting in coherent population transfer between them. The third gate is an effective controlled-phase gate on coherent states of two different oscillators. Such gates should be realizable via reservoir engineering of systems that support tunable nonlinearities, such as trapped ions and circuit QED.

  8. Variable Neural Adaptive Robust Control: A Switched System Approach

    SciTech Connect

    Lian, Jianming; Hu, Jianghai; Zak, Stanislaw H.

    2015-05-01

    Variable neural adaptive robust control strategies are proposed for the output tracking control of a class of multi-input multi-output uncertain systems. The controllers incorporate a variable-structure radial basis function (RBF) network as the self-organizing approximator for unknown system dynamics. The variable-structure RBF network solves the problem of structure determination associated with fixed-structure RBF networks. It can determine the network structure on-line dynamically by adding or removing radial basis functions according to the tracking performance. The structure variation is taken into account in the stability analysis of the closed-loop system using a switched system approach with the aid of the piecewise quadratic Lyapunov function. The performance of the proposed variable neural adaptive robust controllers is illustrated with simulations.

  9. Development of Variable Camber Continuous Trailing Edge Flap System

    NASA Technical Reports Server (NTRS)

    Urnes, Jim, Sr.; Nguyen, Nhan T.; Dykman, John

    2012-01-01

    This presentation describes the current status of the joint NASA/Boeing collaboration on the development of a variable camber continuous trailing edge flap system for use in wing shaping control for cruise drag reduction.

  10. Effects of Mass and Volume Fraction Skewness in Variable Density Mixing Processes

    NASA Astrophysics Data System (ADS)

    Wachtor, Adam J.; Bakosi, Jozsef; Ristorcelli, Raymond

    2015-11-01

    Among the parameters characterizing mixing by variable density turbulence of fluids involving density variations of a factor of 5 to 10 are the Atwood, Froude, Schmidt, and Reynolds numbers. There is evidence that the amount of each fluid present when the two pure fluids mix, as described by the probability density function of the mass or molar (volume) fraction, also strongly affects the mixing process. To investigate this phenomena, implicit large-eddy simulations (ILES) are performed for binary fluid mixtures in statistically homogenous environments under constant acceleration. These coarse grained simulations are used as data for theory validation and mix model development. ILES has been demonstrated to accurately capture the mixing behavior of a passive scalar field through stirring and advection by a turbulent velocity field. The present work advances that research and studies the extent to which an under-resolved active scalar drives the subsequent fluid motion and determines the nature of the mixing process. Effects of initial distributions of the mass and molar (volume) fraction probability density function on the resulting variable density turbulence and mixing are investigated and compared to direct numerical simulations from the Johns Hopkins Turbulence Database. Funded by the LANL LDRD-ER on ``Inserting Nonlinear N-Material Coupling PDF Information into Turbulent Mixing Models'' through exploratory research project number 20150498ER.

  11. Variable-structure facts controllers for power system transient stability

    SciTech Connect

    Wang, Y.; Mohler, R.R.; Spee, R.; Mittelstadt, W. )

    1992-02-01

    In this paper, nonlinear, variable-structure control theory is employed for series capacitor control and braking resistor control to improve the transient stability of a single machine infinite-bus (SMIB) system. A related simulation follows and shows that variable-structure control of the series capacitor (SC) and braking resistor is effective for enhancement of power system steady state performance and transient stability.

  12. Luminous Blue Variables are Antisocial: Their Isolation Implies they are Kicked Mass Gainers in Binary Evolution

    NASA Astrophysics Data System (ADS)

    Tombleson, Ryan; Smith, Nathan

    2015-01-01

    Based on their relatively isolated environments, we argue that luminous blue variables (LBVs) must be primarily the product of binary evolution, challenging the traditional single-star view wherein LBVs mark a brief transition between massive O-type stars and Wolf-Rayet (WR) stars. If the latter were true, then LBVs should be concentrated in young massive clusters like early O-type stars. This is decidedly not the case. Examining locations of LBVs in our Galaxy and the Magellanic Clouds reveals that, with few exceptions, LBVs systematically avoid clusters of O-type stars. In the Large Magellanic Cloud, LBVs are statistically much more isolated than O-type stars, and (perhaps most surprisingly) even more isolated than WR stars. This makes it impossible for LBVs to be single 'massive stars in transition' to WR stars. Instead, we propose that massive stars and supernova (SN) subtypes are dominated by bifurcated evolutionary paths in interacting binaries, wherein most WR stars and SNe Ibc correspond to the mass donors, while LBVs (and their lower-mass analogs like B[e] supergiants, which are even more isolated) are the mass gainers. In this view, LBVs are evolved massive blue stragglers. Through binary mass transfer, rejuvinated mass gainers get enriched, spun up, and sometimes kicked far from their clustered birthsites by their companion's SN. This scenario agrees better with LBVs exploding as Type IIn SNe in isolation, and it predicts that many massive runaway stars may be rapid rotators. Mergers or Thorne-Zykow objects might also give rise to LBVs, but these scenarios may have a harder time explaining why LBVs avoid clusters.

  13. Variable-Speed Wind System Design : Final Report.

    SciTech Connect

    Lauw, Hinan K.; Weigand, Claus H.; Marckx, Dallas A.; Electronic Power Conditioning, Inc.

    1993-10-01

    Almost from the onset of the development of wind energy conversion systems (WECS), it was known that variable-speed operation of the turbine would maximize energy capture. This study was commissioned to assess the cost, efficiency gain, reduction of the cost of energy (COE), and other operating implications of converting the existing hardware of a modern fixed-speed wind energy conversion system to variable-speed operation. The purpose of this study was to develop a preliminary design for the hardware required to allow variable-speed operation using a doubly-fed generator with an existing fixed-speed wind turbine design. The turbine selected for this study is the AWT-26 designed and built by Advanced Wind Turbines Inc. of Redmond, Washington. The lowest projected COE using this variable-speed generation system is projected to be $0.0499/kWh, compared to the lowest possible COE with fixed-speed generation which is projected to be $0.0546/kWh. This translates into a 8.6% reduction of the COE using this variable-speed generation option. The preliminary system design has advanced to where the printed circuit boards can be physically laid out based on the schematics and the system software can be written based on the control flow-charts. The core of hardware and software has been proven to be successful in earlier versions of VSG systems. The body of this report presents the results of the VSWG system development. Operation under normal and fault conditions is described in detail, the system performance for variable-speed operation is estimated and compared to the original fixed-speed system performance, and specifications for all system components (generator, power electronic converter, and system controller) are given. Costs for all components are estimated, and incremental system cost is compared to incremental energy production. Finally, operational features of the VSWG which are not available in the existing FSWG system are outlined.

  14. 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.

  15. The Barents Sea polar front and water masses variability (1980-2011)

    NASA Astrophysics Data System (ADS)

    Oziel, L.; Sirven, J.; Gascard, J.-C.

    2015-03-01

    The polar front separates the warm and saline Atlantic Waters encountered in the western part of the Barents Sea from the cold and fresh Arctic Waters situated in the northern part. These water masses can mix together, mainly in the eastern part of the Barents Sea, generating dense waters in winter which can cascade into the Arctic Ocean to form the Artic Intermediate Waters. To study the interannual variability and evolution of these water masses and the fronts, we have merged data from the International Council for the Exploration of the Sea and the Arctic and Antarctic Research Institute and have built a new database which covers the period 1980-2011. The summer data is interpolated on a regular grid and a "Probability Density Function" method is used to show that the polar front splits into two branches east of 32° E where the topographic constraint weakens. Two fronts can then be defined: the "Northern Polar Front" is associated with strong salinity gradients and the "Southern Polar Front" with temperature gradients. They enclose the dense Barents Sea Water. The interannual variability of the water masses is apparent in the observed data and is linked to that of the ice cover. In contrast, the link with the Arctic Oscillation is not clear. However, results from a general circulation model suggest that such a link could be found if winter data were taken into account. A strong trend, which amplifies during the last decade, is also found: the Atlantic Water occupies a larger volume of the Barents Sea. This "Atlantification" could be accompanied by a northwards displacement of the southern polar front in the eastern part of the Barents Sea (which is suggested by a model based study) and a decrease of the volume occupied by the Arctic Waters.

  16. Long Period Variables in the LMC: Results from MACHO and 2Mass

    SciTech Connect

    Fraser, O J; Cook, K H; Keller, S C; Hawley, S L

    2004-07-19

    We use the eight year light curve database from the MACHO (MAssive Compact Halo Objects) project together with infrared colors and magnitudes from 2MASS (the Two Micron All Sky Survey) to identify a sample of 22,000 long period variables in the Large Magellanic Cloud (referred to hereafter as LMC LPVs). A period luminosity diagram of these stars reveals six well defined sequences, in substantial agreement with previous analyses of samples from OGLE (Optical Gravitational Lensing Experiment). In our analysis we identify analogues to galactic LPVs in the LMC LPV sample. We find that carbon dominated AGB stars populate only two of the sequences, one of which includes the Mira variables. The high luminosity end of the same two sequences are also the location of the only stars with J K{sub s} > 2, indicating that they are enshrouded in dust. The unknown mechanism that produces the variability of the last sequence--those stars with long secondary periods--produces different morphology in the period luminosity diagram than what is seen in the first four sequences, which are thought to be caused by pulsation. In particular, the last sequence extends to lower luminosity RGB stars and the luminosity function does not peak among the AGB stars. We point out several features which will constrain new models of the period luminosity sequences.

  17. Variable Conductance Heat Pipes for Radioisotope Stirling Systems

    NASA Astrophysics Data System (ADS)

    Anderson, William G.; Tarau, Calin

    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 Conductance Heat Pipe (VCHP) was designed to allow multiple stops and restarts of the Stirling engine. A VCHP was designed for the Advanced Stirling Radioisotope Generator, with a 850 °C heater head temperature. The VCHP turns on with a ΔT of 30 °C, which is high enough to not risk standard ASRG operation but low enough to save most heater head life. This VCHP has a low mass, and low thermal losses for normal operation. In addition to the design, a proof-of-concept NaK VCHP was fabricated and tested. While NaK is normally not used in heat pipes, it has an advantage in that it is liquid at the reservoir operating temperature, while Na or K alone would freeze. The VCHP had two condensers, one simulating the heater head, and the other simulating the radiator. The experiments successfully demonstrated operation with the simulated heater head condenser off and on, while allowing the reservoir temperature to vary over 40 to 120 °C, the maximum range expected. In agreement with previous NaK heat pipe tests, the evaporator ΔT was roughly 70 °C, due to distillation of the NaK in the evaporator.

  18. Variability in Intermediate Water Mass Geometry in the Tropical W-Atlantic from LGM to Holocene

    NASA Astrophysics Data System (ADS)

    Poggemann, D. W.; Nuernberg, D.; Hathorne, E. C.; Bruhn, I.; Reißig, S.; Frank, M.

    2014-12-01

    The oceanic intermediate depth response to periods of abrupt climatic cooling during the last deglaciation, namely the Younger Dryas (YD) and Heinrich 1 event (H1), has been the focus of several recent studies (e.g. Pahnke et al., 2008; Huang et al., 2014; Xie et al., 2014; Gebbie et al., 2014). Intermediate water dynamics, in particular the interaction between Antarctic Intermediate Water (AAIW) and North Atlantic Deepwater (NADW) during the transition from the Last Glacial Maximum (LGM) to the Holocene and the connection with Atlantic Meridional Overturning Circulation (AMOC), however, are still debated widely. Several hypotheses suggest the short-term presence of AAIW in the subtropical Atlantic or N-Atlantic sourced intermediate water masses in the Florida Straits during deglacial cool periods when the AMOC was supposedly weak or collapsed (e.g. Xie et al., 2012). This study provides new water mass geometry information from the tropical W-Atlantic for the past 35 ka using a multiproxy approach. We analysed calcitic tests of benthic/planktonic foraminifera from various intermediate depth locations for Mg/Ca (temperature), Cdw (nutrients), δ18Osw (salinity), δ13C (ventilation), and ɛNd (water mass provenance and mixing) in order to improve our understanding of the intermediate water mass distribution and variability between 400 and 1500 m water depth on millennial time-scales. First results document the southward penetration of Glacial North Atlantic Intermediate Water (GNAIW) replacing the NADW during the LGM. Furthermore our data indicate a gradual shift from GNAIW influenced conditions during the LGM to AAIW dominated conditions throughout the Holocene.

  19. Variability of Mass Dependence of Auroral Acceleration Processes with Solar Activity

    NASA Technical Reports Server (NTRS)

    Ghielmetti, Arthur G.

    1997-01-01

    The objectives of this investigation are to improve understanding of the mass dependent variability of the auroral acceleration processes and so to clarify apparent discrepancies regarding the altitude and local time variations with solar cycle by investigating: (1) the global morphological relationships between auroral electric field structures and the related particle signatures under varying conditions of solar activity, and (2) the relationships between the electric field structures and particle signatures in selected events that are representative of the different conditions occurring during a solar cycle. The investigation is based in part on the Lockheed UFI data base of UpFlowing Ion (UFI) events in the 5OO eV to 16keV energy range and associated electrons in the energy range 7O eV to 24 keV. This data base was constructed from data acquired by the ion mass spectrometer on the S3-3 satellite in the altitude range of I to 1.3 Re. The launch of the POLAR spacecraft in early 1996 and successful operation of its TIMAS ion mass spectrometer has provided us with data from within the auroral acceleration regions during the current solar minimum. The perigee of POLAR is at about 1 Re, comparable to that of S3-3. The higher sensitivity and time resolution of TIMAS compared to the ion mass spectrometer on S3-3 together with its wider energy range, 15 eV to 33 keV, facilitate more detailed studies of upflowing ions.

  20. Secular dynamics in hierarchical three-body systems with mass loss and mass transfer

    SciTech Connect

    Michaely, Erez; Perets, Hagai B.

    2014-10-20

    Recent studies have shown that secular evolution of triple systems can play a major role in the evolution and interaction of their inner binaries. Very few studies explored the stellar evolution of triple systems, and in particular the mass-loss phase of the evolving stellar components. Here we study the dynamical secular evolution of hierarchical triple systems undergoing mass loss. We use the secular evolution equations and include the effects of mass loss and mass transfer, as well as general relativistic effects. We present various evolutionary channels taking place in such evolving triples, and discuss both the effects of mass loss and mass transfer in the inner binary system, as well as the effects of mass loss/transfer from an outer third companion. We discuss several distinct types/regimes of triple secular evolution, where the specific behavior of a triple system can sensitively depend on its hierarchy and the relative importance of classical and general relativistic effects. We show that the orbital changes due to mass-loss and/or mass-transfer processes can effectively transfer a triple system from one dynamical regime to another. In particular, mass loss/transfer can both induce and quench high-amplitude (Lidov-Kozai) variations in the eccentricity and inclination of the inner binaries of evolving triples. They can also change the system dynamics from an orderly periodic behavior to a chaotic one, and vice versa.

  1. Variable selection for QSAR by artificial ant colony systems.

    PubMed

    Izrailev, S; Agrafiotis, D K

    2002-01-01

    Derivation of quantitative structure-activity relationships (QSAR) usually involves computational models that relate a set of input variables describing the structural properties of the molecules for which the activity has been measured to the output variable representing activity. Many of the input variables may be correlated, and it is therefore often desirable to select an optimal subset of the input variables that results in the most predictive model. In this paper we describe an optimization technique for variable selection based on artificial ant colony systems. The algorithm is inspired by the behavior of real ants, which are able to find the shortest path between a food source and their nest using deposits of pheromone as a communication agent. The underlying basic self-organizing principle is exploited for the construction of parsimonious QSAR models based on neural networks for several classical QSAR data sets. PMID:12184383

  2. A new active variable stiffness suspension system using a nonlinear energy sink-based controller

    NASA Astrophysics Data System (ADS)

    Anubi, Olugbenga Moses; Crane, Carl D.

    2013-10-01

    This paper presents the active case of a variable stiffness suspension system. The central concept is based on a recently designed variable stiffness mechanism which consists of a horizontal control strut and a vertical strut. The horizontal strut is used to vary the load transfer ratio by actively controlling the location of the point of attachment of the vertical strut to the car body. The control algorithm, effected by a hydraulic actuator, uses the concept of nonlinear energy sink (NES) to effectively transfer the vibrational energy in the sprung mass to a control mass, thereby reducing the transfer of energy from road disturbance to the car body at a relatively lower cost compared to the traditional active suspension using the skyhook concept. The analyses and simulation results show that a better performance can be achieved by subjecting the point of attachment of a suspension system, to the chassis, to the influence of a horizontal NES system.

  3. Roll stabilisation of road vehicles using a variable stiffness suspension system

    NASA Astrophysics Data System (ADS)

    Anubi, Olugbenga Moses; Crane, Carl D., III

    2013-12-01

    A variable stiffness architecture is used in the suspension system to counteract the body roll moment, thereby enhancing the roll stability of the vehicle. The variation of stiffness concept uses the 'reciprocal actuation' to effectively transfer energy between a vertical traditional strut and a horizontal oscillating control mass, thereby improving the energy dissipation of the overall suspension. The lateral dynamics of the system is developed using a bicycle model. The accompanying roll dynamics are also developed and validated using experimental data. The positions of the left and right control masses are sequentially allocated to reduce the effective body roll and roll rate. Simulation results show that the resulting variable stiffness suspension system has more than 50% improvement in roll response over the traditional constant stiffness counterparts. The simulation scenarios examined is the fishhook manoeuvre.

  4. 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.

  5. Precession-driven monsoon variability at the Permian-Triassic boundary — Implications for anoxia and the mass extinction

    NASA Astrophysics Data System (ADS)

    Winguth, Arne; Winguth, Cornelia

    2013-06-01

    By the end of the Late Permian, most continents had collided to form the supercontinent of Pangea. The associated climatic changes at the Permian-Triassic boundary coincided with the most severe mass extinction in the Phanerozoic. One extinction hypothesis favors a climatic response to an increase in large-scale volcanism resulting in ocean stagnation and widespread anoxia with fatal consequences for marine and land organisms. Recent interpretations of geochemical data suggest that orbitally-driven periodic upwelling of toxic hydrogen-sulfide rich water masses contributed to the extinction of species. In this paper, we use the Community Climate System Model (CCSM3) in order to explore the effect of eccentricity-modulated changes of the precession on the strength of Pangean megamonsoons and their impact on productivity and oxygen distribution. The climate model simulates high variability in monsoonal precipitation, trade winds and equatorial upwelling in response to precessional extremes, leading to remarkable fluctuations in the export of carbon from the euphotic zone and hence reduction in dissolved oxygen concentrations in subsurface layers. These findings are in general agreement with increased primary productivity, intensified euxinia within the oxygen-minimum zone, and decimation of the radiolarian zooplankton community as inferred from Japanese marine sections. Strong changes in river run-off linked to precipitation oscillations possibly led to a high variability in the nutrient supply to the Tethys Ocean, thus affecting regional productivity and oxygen distribution. The model results suggest that orbital variability in the sedimentary record and the associated extinction of species are related rather to periodic anoxia in near surface-to-intermediate depth than to widespread anoxic events in the Panthalassic deep-sea.

  6. Modeling and Simulation For A Variable Sprayerrate System

    NASA Astrophysics Data System (ADS)

    Shi, Yan; Liang, Anbo; Yuan, Haibo; Zhang, Chunmei; Li, Junlong

    Variable spraying technology is an important content and developing direction in current plant protection machinery, which can effectively save pesticide and lighten burden of ecological environment in agriculture according to characteristic of spraying targets and speed of aircraft crew. Paper established mathematic model and delivery function of variable spraying system based on designed hardware of variable spraying machine, making use of PID controlling algorithm to simulate in matlab. Simulating result explained that the model can conveniently control gushing amounts and can arrive at satisfied controlling.

  7. Modeling and Simulation For A Variable Sprayerrate System

    NASA Astrophysics Data System (ADS)

    Shi, Yan; Liang, Anbo; Yuan, Haibo; Zhang, Chunmei; Li, Junlong

    Variable spraying technology is an important content and developing direction in current plant protection machinery, which can effectively save pesticide and lighten burden of ecological environment in agriculture according to characteristic of spraying targets and speed of aircraft crew. Paper established mathematic model and delivery function of variable spraying system based on designed hardware of variable spraying machine, making use of PID controlling algorithm to simulate in MATLAB. Simulating result explained that the model can conveniently control gushing amounts and can arrive at satisfied controlling.

  8. 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.

  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

  10. A new approach to the correlation of boundary layer mass transfer rates with thermal diffusion and/or variable properties

    NASA Technical Reports Server (NTRS)

    Srivastava, R.; Rosner, D. E.

    1979-01-01

    A rational approach to the correlation of boundary layer mass transport rates, applicable to many commonly encountered laminar flow conditions with thermal diffusion and/or variable properties, is outlined. The correlation scheme builds upon already available constant property blowing/suction solutions by introducing appropriate correction factors to account for the additional ('pseudo' blowing and source) effects identified with variable properties and thermal diffusion. Applications of the scheme to the particular laminar boundary layer mass transfer problems considered herein (alkali and transition metal compound vapor transport) indicates satisfactory accuracy up to effective blowing factors equivalent to about one third of the 'blow off' value. As a useful by-product of the variable property correlation, we extend the heat-mass transfer analogy, for a wide range of Lewis numbers, to include variable property effects.

  11. 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

  12. Nutrient characteristics of the water masses and their seasonal variability in the eastern equatorial Indian Ocean.

    PubMed

    Sardessai, S; Shetye, Suhas; Maya, M V; Mangala, K R; Prasanna Kumar, S

    2010-01-01

    Nutrient characteristics of four water masses in the light of their thermohaline properties are examined in the eastern Equatorial Indian Ocean during winter, spring and summer monsoon. The presence of low salinity water mass with "Surface enrichments" of inorganic nutrients was observed relative to 20 m in the mixed layer. Lowest oxygen levels of 19 microM at 3 degrees N in the euphotic zone indicate mixing of low oxygen high salinity Arabian Sea waters with the equatorial Indian Ocean. The seasonal variability of nutrients was regulated by seasonally varying physical processes like thermocline elevation, meridional and zonal transport, the equatorial undercurrent and biological processes of uptake and remineralization. Circulation of Arabian Sea high salinity waters with nitrate deficit could also be seen from low N/P ratio with a minimum of 8.9 in spring and a maximum of 13.6 in winter. This large deviation from Redfield N/P ratio indicates the presence of denitrified high salinity waters with a seasonal nitrate deficit ranging from -4.85 to 1.52 in the Eastern Equatorial Indian Ocean.

  13. 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.

  14. Annual and interannual variability of the Barents Sea water masses and polar front: 1980-2011

    NASA Astrophysics Data System (ADS)

    Oziel, Laurent; Sirven, Jerome; Gascard, Jean-Claude

    2015-04-01

    The Barents Sea (BS) is a transition area between the warm and saline Atlantic Waters (AW) and the cold and fresh Arctic Waters (ArW). The BS is characterized by a polar front structure separating AW from ArW. The mixing and cooling of these two water mass generates dense waters in winter. Dense waters are of prior importance because they cascade into the Arctic Ocean to form the Artic Intermediate Waters. This study will use a new hydrographic data set fulfilled by recent stations in the Russian area and a 3D model coupled with atmosphere and ice as a back up to investigate the link between fronts and water masses, as well as their variability over the last 30 years. This study suggests that the polar front structure is composed of two branches and that the dense waters are found in between. The BS, especially in the East, is experiencing an "Atlantification" accompanied with a drastic sea ice decline. These changes, amplified during the last decade, shift the southern branch of the polar front structure in the Norh-East direction and affect negatively the dense water formation. This could have major impacts on the Arctic Ocean ventilation and primary production.

  15. Nutrient characteristics of the water masses and their seasonal variability in the eastern equatorial Indian Ocean.

    PubMed

    Sardessai, S; Shetye, Suhas; Maya, M V; Mangala, K R; Prasanna Kumar, S

    2010-01-01

    Nutrient characteristics of four water masses in the light of their thermohaline properties are examined in the eastern Equatorial Indian Ocean during winter, spring and summer monsoon. The presence of low salinity water mass with "Surface enrichments" of inorganic nutrients was observed relative to 20 m in the mixed layer. Lowest oxygen levels of 19 microM at 3 degrees N in the euphotic zone indicate mixing of low oxygen high salinity Arabian Sea waters with the equatorial Indian Ocean. The seasonal variability of nutrients was regulated by seasonally varying physical processes like thermocline elevation, meridional and zonal transport, the equatorial undercurrent and biological processes of uptake and remineralization. Circulation of Arabian Sea high salinity waters with nitrate deficit could also be seen from low N/P ratio with a minimum of 8.9 in spring and a maximum of 13.6 in winter. This large deviation from Redfield N/P ratio indicates the presence of denitrified high salinity waters with a seasonal nitrate deficit ranging from -4.85 to 1.52 in the Eastern Equatorial Indian Ocean. PMID:20547419

  16. Modelling aperiodic X-ray variability in black hole binaries as propagating mass accretion rate fluctuations: A short review

    NASA Astrophysics Data System (ADS)

    Ingram, A. R.

    2016-05-01

    Black hole binary systems can emit very bright and rapidly varying X-ray signals when material from the companion accretes onto the black hole, liberating huge amounts of gravitational potential energy. Central to this process of accretion is turbulence. In the propagating mass accretion rate fluctuations model, turbulence is generated throughout the inner accretion flow, causing fluctuations in the accretion rate. Fluctuations from the outer regions propagate towards the black hole, modulating the fluctuations generated in the inner regions. Here, I present the theoretical motivation behind this picture before reviewing the array of statistical variability properties observed in the light curves of black hole binaries that are naturally explained by the model. I also discuss the remaining challenges for the model, both in terms of comparison to data and in terms of including more sophisticated theoretical considerations.

  17. The ratio initial mass/payload mass - How good are launch systems?

    NASA Astrophysics Data System (ADS)

    Hornik, Alexander

    1992-04-01

    The growth factor G, defined as the ratio of initial mass/payload mass, is used here to evaluate various rocket launch systems. The qualities of the propulsion, structure, environmental loading, and costs of the Saturn 5, Space Shuttle, Titan III, Saenger Horus C and M, and various Ariane rockets are assessed. The results are used to evaluate the reusability of these propulsion systems.

  18. Link between Mass-loss and Variability Type for AGB Stars?

    NASA Astrophysics Data System (ADS)

    Ivezić, Ž.; Knapp, G. R.

    We find that AGB stars separate in the 25-12 vs. 12-K color-color diagram according to their chemistry (O, S vs. C) and variability type (Miras vs. SRb/Lb). While discrimination according to the chemical composition is not surprising, the separation of Miras from SRb/Lb variables is unexpected. We show that ``standard'' steady-state radiatively driven models provide excellent fits to the color distribution of Miras of all chemical types. However, these models are incapable of explaining the dust emission from O-rich SRb/Lb stars. The models can be altered to fit the data by postulating different optical properties for silicate grains, or by assuming that the dust temperature at the inner envelope radius is significantly lower (300-400 K) than typical condensation temperatures (800-1,000 K), a possibility which is also supported by the detailed characteristics of LRS data. While such lower temperatures are required only for O- and S-rich SRb/Lb stars, they are also consistent with the colors of C-rich SRb/Lb stars. The absence of hot dust for SRb/Lb stars can be interpreted as a recent (order of 100 yr) decrease in the mass-loss rate. The distribution of O-rich SRb/Lb stars in the 25-12 vs. K-12 color-color diagram shows that the mass-loss rate probably resumes again, on similar time scales. It cannot be ruled out that the mass-loss rate is changing periodically on such time scales, implying that the stars might oscillate between the Mira and SRb/Lb phases during their AGB evolution as proposed by Kerschbaum et al. (1996). Such a possibility appears to be supported by recent HST images of the Egg Nebula obtained by Sahai et al. (1997), the discovery of multiple CO winds reported by Knapp et al. (1998), and long-term visual light-curve changes detected for some stars by Mattei (1998).

  19. Link between Mass-loss and Variability Type for AGB Stars?

    NASA Astrophysics Data System (ADS)

    Ivezic, Z.; Knapp, G. R.

    1998-12-01

    We find that AGB stars separate in the 25-12 vs. 12-K color-color diagram according to their chemistry (O, S vs. C) and variability type (Miras vs. SRb/Lb). While discrimination according to the chemical composition is not surprising, the separation of Miras from SRb/Lb variables is unexpected. We show that ``standard'' steady-state radiatively driven models provide excellent fits to the color distribution of Miras of all chemical types. However, these models are incapable of explaining the dust emission from O-rich SRb/Lb stars. The models can be altered to fit the data by postulating different optical properties for silicate grains, or by assuming that the dust temperature at the inner envelope radius is significantly lower (300-400 K) than typical condensation temperatures (800-1000 K), a possibility which is also supported by the detailed characteristics of LRS data. While such lower temperatures are required only for O- and S-rich SRb/Lb stars, they are also consistent with the colors of C-rich SRb/Lb stars. The absence of hot dust for SRb/Lb stars can be interpreted as a recent (order of 100 yr) decrease in the mass-loss rate. The distribution of O-rich SRb/Lb stars in the 25-12 vs. K-12 color-color diagram shows that the mass-loss rate probably resumes again, on similar time scales. It cannot be ruled out that the mass-loss rate is changing periodically on such time scales, implying that the stars might oscillate between the Mira and SRb/Lb phases during their AGB evolution as proposed by Kerschbaum et al. (1996). Such a possibility appears to be supported by recent HST images of the Egg Nebula obtained by Sahai et al. (1997), the discovery of multiple CO winds reported by Knapp et al. (1998), and long-term visual light-curve changes detected for some stars by Mattei (1998).

  20. Probing Cloud-Driven Variability on Two of the Youngest, Lowest-Mass Brown Dwarfs in the Solar Neighborhood

    NASA Astrophysics Data System (ADS)

    Schneider, Adam; Cushing, Michael; Kirkpatrick, J. Davy

    2016-08-01

    Young, late-type brown dwarfs share many properties with directly imaged giant extrasolar planets. They therefore provide unique testbeds for investigating the physical conditions present in this critical temperature and mass regime. WISEA 1147-2040 and 2MASS 1119-1137, two recently discovered late-type (~L7) brown dwarfs, have both been determined to be members of the ~10 Myr old TW Hya Association (Kellogg et al. 2016, Schneider et al. 2016). Each has an estimated mass of 5-6 MJup, making them two of the youngest and lowest-mass free floating objects yet found in the solar neighborhood. As such, these two planetary mass objects provide unparalleled laboratories for investigating giant planet-like atmospheres far from the contaminating starlight of a host sun. Condensate clouds play a critical role in shaping the emergent spectra of both brown dwarfs and gas giant planets, and can cause photometric variability via their non-uniform spatial distribution. We propose to photometrically monitor WISEA 1147-2040 and 2MASS 1119-1137 in order to search for the presence of cloud-driven variability to 1) investigate the potential trend of low surface gravity with high-amplitude variability in a previously unexplored mass regime and 2) explore the angular momentum evolution of isolated planetary mass objects.

  1. Radiological Design Review Screening Mobile Variable Depth Sampling System

    SciTech Connect

    SEILHYMER, C.P.

    2001-01-15

    This document provides the calculated basis for the level of radiological design review required for the proposed Mobile, Variable-Depth Sampling System (MVDSS). This analysis includes the sample station portion of the MVDSS and the associated hose management and sampler positioning system. This analysis does not include the riser interface and the mast deployment system since these two components are internal to the sampled tank.

  2. A method for linearizing a nonlinear system with six state variables and three control variables

    NASA Technical Reports Server (NTRS)

    Hsia, W. S.

    1986-01-01

    A nonlinear system governed by x = f(x,u) with six state variables and three control variables is considered in this project. A set of transformations from (x,u) - space to (z,v) - space is defined such that the linear tangent model is independent of the operating point in the z-space. Therefore, it is possible to design a control law satisfying all operating points in the transformed space. An algorithm to construct the above transformations and to obtain the associated linearized system is described in this report. This method is applied to a rigid body using pole placement for the control law. Results are verified by numerical simulation. Closed loop poles in x-space using traditional local linearization are compared with those pole placements in the z-space.

  3. Synthesis of structural/control systems robust with respect to design variable tolerances

    NASA Technical Reports Server (NTRS)

    Thomas, H. L.; Schmit, L. A.

    1991-01-01

    A methodology is presented for the synthesis of control augmented structures which can be modeled as an assemblage of beam, truss, and nonstructural mass elements augmented by a robust noncollocated direct output feedback control system. The control system is robust in the sense that it can tolerate manufacturing and realization errors. The robust control system is synthesized using a constraint buffering technique in conjunction with the approximation concepts approach to system synthesis. All of the design constraints on the system, including the dynamic stability, are buffered by a nonlinear quantity that is a function of acceptable tolerances on the design variables and the sensitivity of the constraints to changes in these design variables. Numerical results which illustrate the effectiveness of the method presented are given.

  4. Confirmation of mass-independent Ni isotopic variability in iron meteorites

    NASA Astrophysics Data System (ADS)

    Steele, Robert C. J.; Elliott, Tim; Coath, Christopher D.; Regelous, Marcel

    2011-12-01

    We report high-precision analyses of internally-normalised Ni isotope ratios in 12 bulk iron meteorites. Our measurements of 60Ni/ 61Ni, 62Ni/ 61Ni and 64Ni/ 61Ni normalised to 58Ni/ 61Ni and expressed in parts per ten thousand (‱) relative to NIST SRM 986 as ɛ60Ni,ɛ62Ni and ɛ64Ni, vary by 0.146, 0.228 and 0.687, respectively. The precision on a typical analysis is 0.03‱, 0.05‱ and 0.08‱ for ɛ60Ni, ɛ62Ni and ɛ64Ni, respectively, which is comparable to our sample reproducibility. We show that this 'mass-independent' Ni isotope variability cannot be ascribed to interferences, inaccurate correction of instrumental or natural mass-dependent fractionation, fractionation controlled by nuclear field shift effects, nor the influence of cosmic ray spallation. These results thus document the presence of mass-independent Ni isotopic heterogeneity in bulk meteoritic samples, as previously proposed by Regelous et al. (2008) (EPSL 272, 330-338), but our new analyses are more precise and include determination of 64Ni. Intriguingly, we find that terrestrial materials do not yield homogenous internally-normalised Ni isotope compositions, which, as pointed out by Young et al. (2002) (GCA 66, 1095-1104), may be the expected result of using the exponential (kinetic) law and atomic masses to normalise all fractionation processes. The certified Ni isotope reference material NIST SRM 986 defines zero in this study, while appropriate ratios for the bulk silicate Earth are given by the peridotites JP-1 and DTS-2 and, relative to NIST SRM 986, yield deviations in ɛ60Ni, ɛ62Ni and ɛ64Ni of -0.006‱, 0.036‱ and 0.119‱, respectively. There is a strong positive correlation between ɛ64Ni and ɛ62Ni in iron meteorites analyses, with a slope of 3.03 ± 0.71. The variations of Ni isotope anomalies in iron meteorites are consistent with heterogeneous distribution of a nucleosynthetic component from a type Ia supernova into the proto-solar nebula.

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

    SciTech Connect

    Yamaguchi, H.; Shioya, S.; Oda, M.

    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.

  6. Field Assessment of A Variable-rate Aerial Application System

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several experiments were conducted to evaluate the system response of a variable-rate aerial application controller to changing flow rates. The research is collaboration between the USDA, ARS, APTRU and Houma Avionics, USA, manufacturer of a widely used flow controller designed for agricultural airc...

  7. Effect of environmental variables on body size evolution of crinoids between periods of mass extinctions

    NASA Astrophysics Data System (ADS)

    Jani, T.; Heim, N. A.; Payne, J.

    2013-12-01

    Body size plays a major role in determining whether or not an organism can sustain in its local environment. The ecosystem of an animal has a major effect on the fitness of organisms, and it would be interesting to note the degree to which various environmental factors alter body size. In my project, I identify three environmental factors that seem to affect body size of crinoids, marine invertebrates from phylum Echinodermata, and explore how these variables play out in the intervals between the five mass extinctions. The particular factors I study include atmospheric CO2 concentration (proxy for temperature), O2 concentration, and sea level. Although the r and p values for all of these factors were statistically insignificant to definitively make any correlation, there was a visual correlation. For O2, I noted a generally positive correlation with body size over time. CO2 trends suggested a negative correlation until the K-T boundary, but a positive correlation afterwards. Correlation with sea level was a little more complicated: correlation was positive from the start of the Phanerozoic to the Permian extinction; it turned negative until the Cretaceous-Tertiary boundary; afterwards, it again became positive. However, for all three variables, statistical values are too low to say definitively mark any correlation. Out of all three factors, CO2 levels had the highest correlation and lowest p-values in the most time intervals: from the start of the Phanerozoic to Ordovician-Silurian Extinction, from the Late Devonian to the Permian Extinction, and from the Cretaceous-Tertiary boundary to the present. When considering first differences, CO2 levels also had the highest correlation from the Permian Extinction to Triassic-Jurassic Extinction and from the Triassic-Jurassic Extinction to Cretaceous-Tertiary Extinction. Using PaleoTS, I found that body size evolution patterns either seemed to follow either an unbiased random walk (URW) or stasis in the intervals between

  8. Robust nonlinear variable selective control for networked systems

    NASA Astrophysics Data System (ADS)

    Rahmani, Behrooz

    2016-10-01

    This paper is concerned with the networked control of a class of uncertain nonlinear systems. In this way, Takagi-Sugeno (T-S) fuzzy modelling is used to extend the previously proposed variable selective control (VSC) methodology to nonlinear systems. This extension is based upon the decomposition of the nonlinear system to a set of fuzzy-blended locally linearised subsystems and further application of the VSC methodology to each subsystem. To increase the applicability of the T-S approach for uncertain nonlinear networked control systems, this study considers the asynchronous premise variables in the plant and the controller, and then introduces a robust stability analysis and control synthesis. The resulting optimal switching-fuzzy controller provides a minimum guaranteed cost on an H2 performance index. Simulation studies on three nonlinear benchmark problems demonstrate the effectiveness of the proposed method.

  9. The Rorschach Comprehensive System (CS) Psychometric Validity of Individual Variables.

    PubMed

    Tibon Czopp, Shira; Zeligman, Ruth

    2016-01-01

    Since the publication of the Rorschach Inkblot Method (Rorschach, 1921/1942 ), theorists, researchers, and practitioners have been debating the nature of the task, its conceptual foundation, and most important its psychometric properties. The validity of the Rorschach Comprehensive System (CS; Exner, 1974 , 2003; Exner & Weiner, 1995 ) has been supported by several meta-analyses that used different types of nontest external criterion for validating individual variables. In a recent meta-analysis, Mihura, Meyer, Dumitrascu, and Bombel ( 2013 ) found coefficients ranging from modest to excellent for most of the selected CS variables, with 13 of them reported as showing "little to no support." This article focuses on these variables. Although endorsing Mihura et al.'s mainly validating findings, we also suggest that the evidence presented for the little or no validity of these 13 variables is not quite compelling enough to warrant changing their definition or coding, or removing them from the system. We point to some issues concerning the description and interpretation of these variables and the appropriateness of the external criteria used for exploring their validity, and suggest considering these issues in further CS research. Implications of Mihura et al.'s meta-analysis for clinical and forensic practice are discussed. PMID:27153465

  10. PRECISION PHOTOMETRIC MONITORING OF VERY LOW MASS {sigma} ORIONIS CLUSTER MEMBERS: VARIABILITY AND ROTATION AT A FEW Myr

    SciTech Connect

    Cody, Ann Marie; Hillenbrand, Lynne A.

    2010-12-15

    We present high-precision photometry on 107 variable low-mass stars and brown dwarfs in the {approx}3 Myr {sigma} Orionis open cluster. We have carried out I-band photometric monitoring within two fields, encompassing 153 confirmed or candidate members of the low-mass cluster population, from 0.02 to 0.5 M {sub sun}. We are sensitive to brightness changes on timescales from 10 minutes to two weeks with amplitudes as low as 0.004 mag, and find variability on these timescales in nearly 70% of cluster members. We identify both periodic and aperiodic modes of variability, as well as semi-periodic rapid fading events that are not accounted for by the standard explanations of rotational modulation of surface features or accretion. We have incorporated both optical and infrared color data to uncover trends in variability with mass and circumstellar disks. While the data confirm that the lowest-mass objects (M < 0.2 M {sub sun}) rotate more rapidly than the 0.2-0.5 M {sub sun} members, they do not support a direct connection between rotation rate and the presence of a disk. Finally, we speculate on the origin of irregular variability in cluster members with no evidence for disks or accretion.

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

    SciTech Connect

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

    2009-06-15

    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 {mu}m with the UD-DBT reconstruction (at 4 mGy dose) obtained with a voxel size of 100 {mu}m. MCs with sizes of 150 and 180 {mu}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 (A{sub L}) of 0.76 than when using the 3D reconstructed image using the UD acquisition scheme (A{sub L}=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 (A

  12. Modeling the Motion of an Increasing Mass System

    NASA Astrophysics Data System (ADS)

    Kunkel, William; Harrington, Randal

    2010-04-01

    Problems on the dynamics of changing mass systems often call for the more general form of Newton's second law Fnet = dp/dt. These problems usually involve situations where the mass of the system decreases, such as in rocket propulsion. In contrast, this experiment examines a system where the mass increases at a constant rate and the net force remains constant. This system provides a context that is different, and in some ways simpler, than the rocket propulsion systems typically introduced in introductory courses.

  13. Equilibria and vibration of a buckled beam with attached masses or spring-mass systems

    NASA Astrophysics Data System (ADS)

    Plaut, Raymond H.; Virgin, Lawrence N.

    2016-09-01

    A buckled beam with immovable pinned ends is considered. Attached to the beam are either one concentrated mass, two concentrated masses, a spring-mass system (that could model a human, robot, or passive vibration absorber), or a horizontal rigid bar with two vertical end springs (a "bounce-pitch" system that could model an animal or a vehicle). In the theoretical analysis, the beam is modeled as an inextensible elastica. Equilibrium configurations are determined first. Then small free vibrations about equilibrium are examined, and the lowest frequencies and corresponding modes are computed. The effects of various parameters are investigated, such as the ratio of the span to the total arc length of the beam, the locations and weights of the attached masses and systems, and the stiffnesses of the springs. For the case of a single attached mass, experiments are conducted and the results are compared to the theoretical ones.

  14. Variable stiffness and damping suspension system for train

    NASA Astrophysics Data System (ADS)

    Sun, Shuaishuai; Deng, Huaxia; Li, Weihua

    2014-03-01

    As the vibration of high speed train becomes fierce when the train runs at high speed, it is crucial to develop a novel suspension system to negotiate train's vibration. This paper presents a novel suspension based on Magnetorheological fluid (MRF) damper and MRF based smart air spring. The MRF damper is used to generate variable damping while the smart air spring is used to generate field-dependent stiffness. In this paper, the two kind smart devices, MRF dampers and smart air spring, are developed firstly. Then the dynamic performances of these two devices are tested by MTS. Based on the testing results, the two devices are equipped to a high speed train which is built in ADAMS. The skyhook control algorithm is employed to control the novel suspension. In order to compare the vibration suppression capability of the novel suspension with other kind suspensions, three other different suspension systems are also considered and simulated in this paper. The other three kind suspensions are variable damping with fixed stiffness suspension, variable stiffness with fixed damping suspension and passive suspension. The simulation results indicate that the variable damping and stiffness suspension suppresses the vibration of high speed train better than the other three suspension systems.

  15. 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.

  16. Search for Low-mass Objects in the Globular Cluster M4. I. Detection of Variable Stars

    NASA Astrophysics Data System (ADS)

    Safonova, M.; Mkrtichian, D.; Hasan, P.; Sutaria, F.; Brosch, N.; Gorbikov, E.; Joseph, P.

    2016-02-01

    With every new discovery of an extrasolar planet, the absence of planets in globular clusters (GCs) becomes more and more conspicuous. Null detection of transiting hot Jupiters in GCs 47 Tuc, ω Cen, and NGC 6397 presents an important puzzle, raising questions about the role played by cluster metallicity and environment on formation and survival of planetary systems in densely populated stellar clusters. GCs were postulated to have many free-floating planets, for which microlensing (ML) is an established tool for detection. Dense environments, well-constrained distances and kinematics of lenses and sources, and photometry of thousands of stars simultaneously make GCs the ideal targets to search for ML. We present first results of a multisite, 69-night-long campaign to search for ML signatures of low-mass objects in the GC M4, which was chosen because of its proximity, location, and the actual existence of a planet. M4 was observed in R and I bands by two telescopes, 1 m T40 and 18-inch C18, of the Wise Observatory, Tel Aviv, Israel, from 2011 April to July. Observations on the 1 m telescope were carried out in service mode, gathering 12 to 48 20 s exposures per night for a total of 69 nights. C18 observations were done for about 4 hr a night for six nights in 2011 May. We employ a semiautomated pipeline to calibrate and reduce the images to the light curves that our group is developing for this purpose, which includes the differential photometry package DIAPL, written by Wozniak and modified by W. Pych. Several different diagnostics are employed for search of variability/transients. While no high-significance ML event was found in this observational run, we have detected more than 20 new variables and variable candidates in the M4 field, which we present here.

  17. 2MASS J17112318-2724315: A DEEPLY EMBEDDED LOW-MASS PROTOSTELLAR SYSTEM IN THE B59 MOLECULAR CLOUD

    SciTech Connect

    Riaz, B.; Martin, E. L.; Bouy, H.; Tata, R.

    2009-08-01

    We present near-infrared observations of the low-mass deeply embedded Class 0/I system 2MASS J17112318-2724315 (2M171123) in the B59 molecular cloud. Bright scattered light nebulosity is observed toward this source in the K{sub s} images, that seems to trace the edges of an outflow cavity. We report the detection of a low-luminosity protostar 2M17112255-27243448 (2M17112255) that lies {approx}8'' ({approx}1000 AU) from 2M171123. This is a Class I system, as indicated by its 2-8 {mu}m slope and Infrared Array Camera colors, with an estimated internal luminosity of {approx}0.3 L{sub sun}. We estimate a mass of {approx}0.12-0.25 M{sub sun} for this source, at an age of 0.1-1 Myr. Also presented is detailed modeling of the 2M171123 system. The best-fit parameters indicate a large envelope density of the order of {approx}10{sup -13} g cm{sup -3}, and an intermediate inclination between 53 deg. and 59 deg. The observed K{sub s} -band variability for this system could be explained by slight variability in the mass infall rate between 2.5E-5 and 1.8E-5 M{sub sun} yr{sup -1}. The protostar 2M171123 exhibits a rarely observed absorption feature near 11.3 {mu}m within its 10 {mu}m silicate band. We find a strong correlation between the strength in this 11.3 {mu}m 'edge' and the H{sub 2}O-ice column density, indicating the origin of this feature in the thickness of the ice mantle over the silicate grains.

  18. Complex systems and the technology of variability analysis

    PubMed Central

    Seely, Andrew JE; Macklem, Peter T

    2004-01-01

    Characteristic patterns of variation over time, namely rhythms, represent a defining feature of complex systems, one that is synonymous with life. Despite the intrinsic dynamic, interdependent and nonlinear relationships of their parts, complex biological systems exhibit robust systemic stability. Applied to critical care, it is the systemic properties of the host response to a physiological insult that manifest as health or illness and determine outcome in our patients. Variability analysis provides a novel technology with which to evaluate the overall properties of a complex system. This review highlights the means by which we scientifically measure variation, including analyses of overall variation (time domain analysis, frequency distribution, spectral power), frequency contribution (spectral analysis), scale invariant (fractal) behaviour (detrended fluctuation and power law analysis) and regularity (approximate and multiscale entropy). Each technique is presented with a definition, interpretation, clinical application, advantages, limitations and summary of its calculation. The ubiquitous association between altered variability and illness is highlighted, followed by an analysis of how variability analysis may significantly improve prognostication of severity of illness and guide therapeutic intervention in critically ill patients. PMID:15566580

  19. Complex systems and the technology of variability analysis.

    PubMed

    Seely, Andrew J E; Macklem, Peter T

    2004-12-01

    Characteristic patterns of variation over time, namely rhythms, represent a defining feature of complex systems, one that is synonymous with life. Despite the intrinsic dynamic, interdependent and nonlinear relationships of their parts, complex biological systems exhibit robust systemic stability. Applied to critical care, it is the systemic properties of the host response to a physiological insult that manifest as health or illness and determine outcome in our patients. Variability analysis provides a novel technology with which to evaluate the overall properties of a complex system. This review highlights the means by which we scientifically measure variation, including analyses of overall variation (time domain analysis, frequency distribution, spectral power), frequency contribution (spectral analysis), scale invariant (fractal) behaviour (detrended fluctuation and power law analysis) and regularity (approximate and multiscale entropy). Each technique is presented with a definition, interpretation, clinical application, advantages, limitations and summary of its calculation. The ubiquitous association between altered variability and illness is highlighted, followed by an analysis of how variability analysis may significantly improve prognostication of severity of illness and guide therapeutic intervention in critically ill patients. PMID:15566580

  20. Long term mass changes and interannual variability in the Canadian Archipelago and Gulf of Alaska from GRACE

    NASA Astrophysics Data System (ADS)

    Harig, C.; Simons, F. J.

    2015-12-01

    The mass transfer from land ice to the oceans is a major contributor to global sea-level rise. The glaciated regions of the Canadian Archipelago and the Gulf of Alaska are the next largest ice mass loss contributors outside of the Greenland and Antarctic ice sheets. Here we estimate the ice mass change of these regions since 2003 using time-variable gravity data from the GRACE mission. We employ an estimation technique based on spherical Slepian localization functions. These Slepian functions form a sparse set of orthogonal basis functions for a specific region and maximize the signal-to-noise levels of the gravity fields, making them excellent candidates to analyze regional data on the sphere.Between 2003 and 2012 Ellesmere Island lost mass (-38 Gt/yr) at an accelerating rate (-8 Gt/yr2), while Baffin Island lost mass at a lower rate (-22 Gt/yr) with very low acceleration. During this time, interannual variations were well described by an average seasonal cycle. Since 2013 ice mass in Ellesmere and Baffin islands, as well as Greenland, have diverged from their long term mass change trends. During the summer of 2013 these areas had the lowest recorded melt since the start of the GRACE mission. Through the end of 2014, the difference between the observed mass and the extrapolated long term trend for Greenland grew to over 500 gigatons. In contrast to the Canadian Archipelago, the Gulf of Alaska region has average seasonal mass variations four times larger per unit area and greater variability from year to year. Recent years of below average mass loss have lowered the average mass loss rate from previous estimates.

  1. Inclusive B-meson production at the LHC in the general-mass variable-flavor-number scheme

    SciTech Connect

    Kniehl, B. A.; Kramer, G.; Schienbein, I.

    2011-11-01

    We calculate the next-to-leading-order cross section for the inclusive production of B mesons in pp collisions in the general-mass variable-flavor-number scheme, an approach that takes into account the finite mass of the b quarks. We use realistic evolved nonperturbative fragmentation functions obtained from fits to e{sup +}e{sup -} data and compare our results for the transverse-momentum and rapidity distributions at a center-of-mass energy of 7 TeV with recent data from the CMS Collaboration at the CERN LHC. We find good agreement, in particular, at large values of p{sub T}.

  2. MEASURING THE MASS OF SOLAR SYSTEM PLANETS USING PULSAR TIMING

    SciTech Connect

    Champion, D. J.; Hobbs, G. B.; Manchester, R. N.; Edwards, R. T.; Burke-Spolaor, S.; Sarkissian, J. M.; Backer, D. C.; Bailes, M.; Bhat, N. D. R.; Van Straten, W.; Coles, W.; Demorest, P. B.; Ferdman, R. D.; Purver, M. B.; Folkner, W. M.; Hotan, A. W.; Kramer, M.; Lommen, A. N.; Nice, D. J.; Stairs, I. H.

    2010-09-10

    High-precision pulsar timing relies on a solar system ephemeris in order to convert times of arrival (TOAs) of pulses measured at an observatory to the solar system barycenter. Any error in the conversion to the barycentric TOAs leads to a systematic variation in the observed timing residuals; specifically, an incorrect planetary mass leads to a predominantly sinusoidal variation having a period and phase associated with the planet's orbital motion about the Sun. By using an array of pulsars (PSRs J0437-4715, J1744-1134, J1857+0943, J1909-3744), the masses of the planetary systems from Mercury to Saturn have been determined. These masses are consistent with the best-known masses determined by spacecraft observations, with the mass of the Jovian system, 9.547921(2) x10{sup -4} M {sub sun}, being significantly more accurate than the mass determined from the Pioneer and Voyager spacecraft, and consistent with but less accurate than the value from the Galileo spacecraft. While spacecraft are likely to produce the most accurate measurements for individual solar system bodies, the pulsar technique is sensitive to planetary system masses and has the potential to provide the most accurate values of these masses for some planets.

  3. Mass transport in annular spherical system

    NASA Astrophysics Data System (ADS)

    Bauer, Helmut F.

    The mass transport between two concentric spheres with inlet and outlet at the poles was determined for ideal liquid flow (plug flow) and laminar flow for constant concentration at the spherical walls and constant concentration at the inlet. Velocity distribution and local concentration profiles were determined analytically for various widths of the annular spherical conduit and various diffusive flow parameters. It is found that with the increase of this parameter, the decay becomes quite rapid and that the same effect occurs for increasing diameter ratio of the spheres. This configuration may possibly be used as a basic element of an artificial kidney.

  4. Managing variability in the IO performance of petascale storage systems.

    SciTech Connect

    Wolf, Matthew; Zheng, Fang; Klasky, Scott; Schwan, Karsten; Oldfield, Ron A.; Lofstead, Gerald Fredrick, II; Liu, Qing; Kordenbrock, Todd

    2010-11-01

    Significant challenges exist for achieving peak or even consistent levels of performance when using IO systems at scale. They stem from sharing IO system resources across the processes of single large-scale applications and/or multiple simultaneous programs causing internal and external interference, which in turn, causes substantial reductions in IO performance. This paper presents interference effects measurements for two different file systems at multiple supercomputing sites. These measurements motivate developing a 'managed' IO approach using adaptive algorithms varying the IO system workload based on current levels and use areas. An implementation of these methods deployed for the shared, general scratch storage system on Oak Ridge National Laboratory machines achieves higher overall performance and less variability in both a typical usage environment and with artificially introduced levels of 'noise'. The latter serving to clearly delineate and illustrate potential problems arising from shared system usage and the advantages derived from actively managing it.

  5. Analysis of a Linear System for Variable-Thrust Control in the Terminal Phase of Rendezvous

    NASA Technical Reports Server (NTRS)

    Hord, Richard A.; Durling, Barbara J.

    1961-01-01

    A linear system for applying thrust to a ferry vehicle in the 3 terminal phase of rendezvous with a satellite is analyzed. This system requires that the ferry thrust vector per unit mass be variable and equal to a suitable linear combination of the measured position and velocity vectors of the ferry relative to the satellite. The variations of the ferry position, speed, acceleration, and mass ratio are examined for several combinations of the initial conditions and two basic control parameters analogous to the undamped natural frequency and the fraction of critical damping. Upon making a desirable selection of one control parameter and requiring minimum fuel expenditure for given terminal-phase initial conditions, a simplified analysis in one dimension practically fixes the choice of the remaining control parameter. The system can be implemented by an automatic controller or by a pilot.

  6. 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

  7. 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.

  8. Bipartite entanglement in continuous-variable tripartite systems

    NASA Astrophysics Data System (ADS)

    Olsen, M. K.; Corney, J. F.

    2016-11-01

    In the field of continuous-variable tripartite entanglement, the systems utilised can be either asymmetric or symmetric. It is therefore of interest to examine the differences in the entanglement properties of these two types of system, using two examples that are known to produce tripartite entanglement. We examine one asymmetric and one fully symmetric Gaussian continuous-variable system in terms of their tripartite and bipartite entanglement properties. We first treat pure states and are able to find analytic solutions using the undepleted pump approximation for the Hamiltonian models. Our symmetric system exhibits perfect tripartite correlations, but only in the unphysical limit of infinite squeezing. For more realistic squeezing parameters, the two systems exhibit both tripartite and bipartite entanglement. Secondly we treat the more experimentally reasonable situation where the interactions take place inside optical cavities and we are dealing with mixed states. In these cases, where the criteria for genuine tripartite entanglement are more stringent, we find that tripartite entanglement is still available, although over smaller bandwidths than three-mode inseparability. In general, the spectral results are consistent with the analytical solutions. We conclude that none of the outputs are completely analogous to either GHZ or W states, but there are parameter regions of the Hamiltonian dynamics where they produce T states as introduced by Adesso et al. [1,2]. In the intracavity cases, both bipartite entanglement and tripartite inseparability are always present, with genuine tripartite entanglement appearing as the pumping rate is increased. The qualitative differences in the output states for different interaction parameters indicate that continuous-variable tripartite quantum information systems offer a versatility not found in two-mode bipartite systems.

  9. Dynamic analysis of coupled vehicle-bridge system with uniformly variable speed

    NASA Astrophysics Data System (ADS)

    Wei-zhen, Li; Chang-ping, Chen; Yi-qi, Mao; Chang-zhao, Qian

    2016-09-01

    In this paper, a planar biaxial vehicle model with four degrees of freedom is presented based on spring-damping-mass system theory. By using Runge-Kutta method, the dynamic characteristics of a simply support bridge acting by moving vehicle with uniform variable speed are analyzed, and the effects of inertia force, relative acceleration and initial velocity are taken into consideration in the present research. The time-deflection response curves of the bridge under the variation of initial speed and acceleration are analyzed. Some valuable results are found which can provide a theoretical direction for the consideration of dynamical characteristics in design of bridge system.

  10. 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.

  11. 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

  12. Screening of Different Media and Substrates for Cultural Variability and Mass Culture of Arthrobotrys dactyloides Drechsler.

    PubMed

    Kumar, D; Singh, K P; Jaiswal, R K

    2005-12-01

    Variability in growth and sporulation of five isolates of Arthrobotrys dactyloides was studied on five agar, 6 bran and 5 grain media. Potato dextrose agar (PDA) supported maximum growth of isolate A, C and E, while growth of isolate B and D was significantly lower on this medium. On Czapek's agar and yeast glucose agar media the differentiation in the isolates in relation to growth was poor than PDA. The other two media showed much poorer differentiation. On Czapek's agar medium, sporulation was recorded in isolate B only, whereas other isolates showed rare sporulation. Among the bran media, pea bran agar medium supported maximum growth of all the isolates except isolate B. Gram and rice bran agar media were next best. However, the growth of isolate B on the gram bran agar medium was more or less equal as other isolates. On pigeon pea bran agar medium, isolate E failed to grow while other isolates recorded poor growth. On lentil bran agar medium, only isolate B and D recorded little growth, whereas other isolates failed to grow. All the isolates recorded good sporulation on bran agar media except pigeon pea and lentil bran agar media. The grain agar media supported moderate to very good growth of all the isolates. In general isolate B remained slow growing on these media except gram grain and sorghum grain agar media on which growth of this isolate was comparable to other isolates. Sporulation in general, was good on all the grain agar media. Among different substrates screened, barley grain and pea bran were found superior to others for mass culture of isolate A of A. dactyloides.

  13. Time-Variable Gravity Signal due to Extratropic Pacific Water Mass Redistribution

    NASA Technical Reports Server (NTRS)

    Chao, B. F.; Boy, J. -P.; Cox, C. M.; Au, A. Y.

    2003-01-01

    Using the satellite-laser-ranging (SLR) data, Cox and Chao [2002] reported the detection of a large post-1998 anomaly (in the form of a positive jump) in the time series of Earth s lowest-degree gravity harmonic 52, or the dynamic oblateness. Among several groups now examining the mass redistribution in the global geophysical fluids in search of the cause(s), we report here a temporally coinciding anomalies found in the extratropic north + south Pacific basins. Clearly seen in the leading EOFPC mode for extratropic Pacific, these anomalies occurred in sea-surface height, sea-surface temperature, and temperature- and salinity-depth profiles. We based our analysis on two different data sources: TOPEX/Poseidon altimetry, and the ECCO ocean general circulation model output assimilating T/P data. The magnitude of these changes, when converted to equivalent J2 change, appears to be a few times too small to explain the observed J2 directly. These findings, and the fact that the anomalies occurred following the strong 1997-98 El Nino, suggest strong geophysical connection of the interannual-to-decadal variation of 52 with the Pacific Decadal Oscillation (PDO) and the ultimate global-change processes that cause PDO. More work is underway, and additional independent data sources are examined, paying close attention to the fact that the J2 anomaly has been reversing back to normal since 2001. These include: (1) cryospheric contributions (melting of glaciers and ice sheets); (2) land hydrological contributions; (3) polar sea influences ( e g , via deep flow); (4) fluid flow in Earth's core; (5) time-variable gravity signals from SLR in higher harmonic degree/order, including J3,J4, (2,1), and (2,2) coefficients, considering their lower signal-to-noise ratios; (6) Earth rotation data in terms of length-of-day and polar motion.

  14. Time-variable gravity signal due to extratropic Pacific water mass redistribution

    NASA Astrophysics Data System (ADS)

    Chao, B. F.; Boy, J.-P.; Cox, C.; Au, A.

    2003-04-01

    Using the satellite-laser-ranging (SLR) data, Cox and Chao [2002] reported the detection of a large post-1998 anomaly (in the form of a positive "jump") in the time series of Earth's lowest-degree gravity harmonic J2, or the dynamic oblateness. Among several groups now examining the mass redistribution in the global geophysical fluids in search of the cause(s), we report here a temporally coinciding anomalies found in the extratropic north + south Pacific basins. Clearly seen in the leading EOF/PC mode for extratropic Pacific, these anomalies occurred in sea-surface height, sea-surface temperature, and temperature- and salinity-depth profiles. We based our analysis on two different data sources: TOPEX/Poseidon altimetry, and the ECCO ocean general circulation model output assimilating T/P data. The magnitude of these changes, when converted to equivalent J2 change, appears to be a few times too small to explain the observed J2 directly. These findings, and the fact that the anomalies occurred following the strong 1997-98 El Nino, suggest strong geophysical connection of the interannual-to-decadal variation of J2 with the Pacific Decadal Oscillation (PDO) and the ultimate global-change processes that cause PDO. More work is underway, and additional independent data sources are examined, paying close attention to the fact that the J2 anomaly has been reversing back to "normal" since 2001. These include: (1) cryospheric contributions (melting of glaciers and ice sheets); (2) land hydrological contributions; (3) polar sea influences (e.g., via deep flow); (4) fluid flow in Earth's core; (5) time-variable gravity signals from SLR in higher harmonic degree/order, including J3, J4, (2,1), and (2,2) coefficients, considering their lower signal-to-noise ratios; (6) Earth rotation data in terms of length-of-day and polar motion.

  15. Variable-structure TCSC control in multimachine power systems

    SciTech Connect

    Wang, Y.; Mittelstadt, B.; Mohler, R.

    1996-11-01

    Due to the long distances which separate electric power generation resources from electric load centers, utility planning engineers have been searching for ways to increase transfer capability while maintaining system stability and good damping performance. The traditional solution to this problem has been to reduce transfer impedance by constructing additional transmission lines. However, high cost, very long lead time and environmental concerns become more and more severe restrictions to this option. In recent years, new power-electronic technology has been the basis for a program sponsored by the Electric Power Research Institute known as Flexible AC Transmission System (FACTS). Related devices such as the thyristor-controlled series-capacitor (TCSC), thyristor-controlled braking-resistor (TCBR) and thyristor-controlled static-Var-compensator are appropriately linked to powerful network control measures because they are able to respond very quickly to meet system demands under transient conditions. To utilize this capability, appropriate control for the thyristors must be developed. This task becomes a big challenge for control experts because the power system is very large scale geographically, highly nonlinear and of variable structure. In this paper, the multimachine power system model with TCSC is derived; then the control law is designed. Using the Bonneville Power Administration transient stability program, the variable-structure TCSC control is tested in a 54-bus system.

  16. 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.

  17. Measures of quantum synchronization in continuous variable systems.

    PubMed

    Mari, A; Farace, A; Didier, N; Giovannetti, V; Fazio, R

    2013-09-01

    We introduce and characterize two different measures which quantify the level of synchronization of coupled continuous variable quantum systems. The two measures allow us to extend to the quantum domain the notions of complete and phase synchronization. The Heisenberg principle sets a universal bound to complete synchronization. The measure of phase synchronization is, in principle, unbounded; however, in the absence of quantum resources (e.g., squeezing) the synchronization level is bounded below a certain threshold. We elucidate some interesting connections between entanglement and synchronization and, finally, discuss an application based on quantum optomechanical systems. PMID:25166668

  18. Quantifying Interannual Variability for Photovoltaic Systems in PVWatts

    SciTech Connect

    Ryberg, David Severin; Freeman, Janine; Blair, Nate

    2015-10-01

    The National Renewable Energy Laboratory's (NREL's) PVWatts is a relatively simple tool used by industry and individuals alike to easily estimate the amount of energy a photovoltaic (PV) system will produce throughout the course of a typical year. PVWatts Version 5 has previously been shown to be able to reasonably represent an operating system's output when provided with concurrent weather data, however this type of data is not available when estimating system output during future time frames. For this purpose PVWatts uses weather data from typical meteorological year (TMY) datasets which are available on the NREL website. The TMY files represent a statistically 'typical' year which by definition excludes anomalous weather patterns and as a result may not provide sufficient quantification of project risk to the financial community. It was therefore desired to quantify the interannual variability associated with TMY files in order to improve the understanding of risk associated with these projects. To begin to understand the interannual variability of a PV project, we simulated two archetypal PV system designs, which are common in the PV industry, in PVWatts using the NSRDB's 1961-1990 historical dataset. This dataset contains measured hourly weather data and spans the thirty years from 1961-1990 for 239 locations in the United States. To note, this historical dataset was used to compose the TMY2 dataset. Using the results of these simulations we computed several statistical metrics which may be of interest to the financial community and normalized the results with respect to the TMY energy prediction at each location, so that these results could be easily translated to similar systems. This report briefly describes the simulation process used and the statistical methodology employed for this project, but otherwise focuses mainly on a sample of our results. A short discussion of these results is also provided. It is our hope that this quantification of the

  19. Mass storage system reference model, Version 4

    NASA Technical Reports Server (NTRS)

    Coleman, Sam (Editor); Miller, Steve (Editor)

    1993-01-01

    The high-level abstractions that underlie modern storage systems are identified. The information to generate the model was collected from major practitioners who have built and operated large storage facilities, and represents a distillation of the wisdom they have acquired over the years. The model provides a common terminology and set of concepts to allow existing systems to be examined and new systems to be discussed and built. It is intended that the model and the interfaces identified from it will allow and encourage vendors to develop mutually-compatible storage components that can be combined to form integrated storage systems and services. The reference model presents an abstract view of the concepts and organization of storage systems. From this abstraction will come the identification of the interfaces and modules that will be used in IEEE storage system standards. The model is not yet suitable as a standard; it does not contain implementation decisions, such as how abstract objects should be broken up into software modules or how software modules should be mapped to hosts; it does not give policy specifications, such as when files should be migrated; does not describe how the abstract objects should be used or connected; and does not refer to specific hardware components. In particular, it does not fully specify the interfaces.

  20. 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.

  1. Small system for tritium accelerator mass spectrometry

    DOEpatents

    Roberts, Mark L.; Davis, Jay C.

    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.

  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. Extremal entanglement and mixedness in continuous variable systems

    SciTech Connect

    Adesso, Gerardo; Serafini, Alessio; Illuminati, Fabrizio

    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. Two-Stage Variable Sample-Rate Conversion System

    NASA Technical Reports Server (NTRS)

    Tkacenko, Andre

    2009-01-01

    A two-stage variable sample-rate conversion (SRC) system has been pro posed as part of a digital signal-processing system in a digital com munication radio receiver that utilizes a variety of data rates. The proposed system would be used as an interface between (1) an analog- todigital converter used in the front end of the receiver to sample an intermediatefrequency signal at a fixed input rate and (2) digita lly implemented tracking loops in subsequent stages that operate at v arious sample rates that are generally lower than the input sample r ate. This Two-Stage System would be capable of converting from an input sample rate to a desired lower output sample rate that could be var iable and not necessarily a rational fraction of the input rate.

  5. Variable buoyancy system for unmanned multi-domain vehicles

    NASA Astrophysics Data System (ADS)

    MacLeod, Marc; Bryant, Matthew

    2016-04-01

    This paper presents the system design, construction, and testing of an active variable buoyancy system (VBS) actuator with applications to unmanned multi-domain vehicles. Unmanned multi-domain vehicles require nontraditional VBS designs because of their unique operation requirements. We present a VBS actuator design that targets multi-domain vehicle design objectives of high endurance, stealth, and underwater loitering. The design features a rigid ballast tank with an inner elastic bladder connected to a hydraulic pump and a proportionally controlled vent valve. The system working fluid is obtained from the ambient surrounding water and the elastic bladder separates the water from pressurized gas, thus preventing any gas from escaping during a venting operation. An analytic model of the VBS characterizing the system dynamics is derived. Ballast tank prototype design and construction is discussed. A VBS test platform vehicle is presented, featuring two ballast tanks, motor, pump, and RF receiver for control.

  6. Search for systemic mass loss in Algols with bow shocks

    NASA Astrophysics Data System (ADS)

    Mayer, A.; Deschamps, R.; Jorissen, A.

    2016-03-01

    Aims: Various studies indicate that interacting binary stars of Algol type evolve non-conservatively. However, direct detections of systemic mass loss in Algols have been scarce so far. We study the systemic mass loss in Algols by looking for the presence of infrared excesses originating from the thermal emission of dust grains, which is linked to the presence of a stellar wind. Methods: In contrast to previous studies, we make use of the fact that stellar and interstellar material is piled up at the edge of the astrosphere where the stellar wind interacts with the interstellar medium. We analyse WISE W3 12 μm and WISE W4 22 μm data of Algol-type binary Be and B[e] stars and the properties of their bow shocks. From the stand-off distance of the bow shock we are able to determine the mass-loss rate of the binary system. Results: Although the velocities of the stars with respect to the interstellar medium are quite low, we find bow shocks present in two systems, namely π Aqr, and ϕ Per; a third system, CX Dra, shows a more irregular circumstellar environment morphology which might somehow be related to systemic mass loss. The properties of the two bow shocks point to mass-loss rates and wind velocities typical of single B stars, which do not support an enhanced systemic mass loss.

  7. Mesoscale and severe storms (Mass) data management and analysis system

    NASA Technical Reports Server (NTRS)

    Hickey, J. S.; Karitani, S.; Dickerson, M.

    1984-01-01

    Progress on the Mesoscale and Severe Storms (MASS) data management and analysis system is described. An interactive atmospheric data base management software package to convert four types of data (Sounding, Single Level, Grid, Image) into standard random access formats is implemented and integrated with the MASS AVE80 Series general purpose plotting and graphics display data analysis software package. An interactive analysis and display graphics software package (AVE80) to analyze large volumes of conventional and satellite derived meteorological data is enhanced to provide imaging/color graphics display utilizing color video hardware integrated into the MASS computer system. Local and remote smart-terminal capability is provided by installing APPLE III computer systems within individual scientist offices and integrated with the MASS system, thus providing color video display, graphics, and characters display of the four data types.

  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. Realtime Multichannel System for Beat to Beat QT Interval Variability

    NASA Technical Reports Server (NTRS)

    Starc, Vito; Schlegel, Todd T.

    2006-01-01

    The measurement of beat-to-beat QT interval variability (QTV) shows clinical promise for identifying several types of cardiac pathology. However, until now, there has been no device capable of displaying, in real time on a beattobeat basis, changes in QTV in all 12 conventional leads in a continuously monitored patient. While several software programs have been designed to analyze QTV, heretofore, such programs have all involved only a few channels (at most) and/or have required laborious user interaction or offline calculations and postprocessing, limiting their clinical utility. This paper describes a PC-based ECG software program that in real time, acquires, analyzes and displays QTV and also PQ interval variability (PQV) in each of the eight independent channels that constitute the 12lead conventional ECG. The system also processes certain related signals that are derived from singular value decomposition and that help to reduce the overall effects of noise on the realtime QTV and PQV results.

  10. Paper spray mass spectrometry and PLS-DA improved by variable selection for the forensic discrimination of beers.

    PubMed

    Pereira, Hebert Vinicius; Amador, Victória Silva; Sena, Marcelo Martins; Augusti, Rodinei; Piccin, Evandro

    2016-10-12

    Paper spray mass spectrometry (PS-MS) combined with partial least squares discriminant analysis (PLS-DA) was applied for the first time in a forensic context to a fast and effective differentiation of beers. Eight different brands of American standard lager beers produced by four different breweries (141 samples from 55 batches) were studied with the aim at performing a differentiation according to their market prices. The three leader brands in the Brazilian beer market, which have been subject to fraud, were modeled as the higher-price class, while the five brands most used for counterfeiting were modeled as the lower-price class. Parameters affecting the paper spray ionization were examined and optimized. The best MS signal stability and intensity was obtained while using the positive ion mode, with PS(+) mass spectra characterized by intense pairs of signals corresponding to sodium and potassium adducts of malto-oligosaccharides. Discrimination was not apparent neither by using visual inspection nor principal component analysis (PCA). However, supervised classification models provided high rates of sensitivity and specificity. A PLS-DA model using full scan mass spectra were improved by variable selection with ordered predictors selection (OPS), providing 100% of reliability rate and reducing the number of variables from 1701 to 60. This model was interpreted by detecting fifteen variables as the most significant VIP (variable importance in projection) scores, which were therefore considered diagnostic ions for this type of beer counterfeit.

  11. Paper spray mass spectrometry and PLS-DA improved by variable selection for the forensic discrimination of beers.

    PubMed

    Pereira, Hebert Vinicius; Amador, Victória Silva; Sena, Marcelo Martins; Augusti, Rodinei; Piccin, Evandro

    2016-10-12

    Paper spray mass spectrometry (PS-MS) combined with partial least squares discriminant analysis (PLS-DA) was applied for the first time in a forensic context to a fast and effective differentiation of beers. Eight different brands of American standard lager beers produced by four different breweries (141 samples from 55 batches) were studied with the aim at performing a differentiation according to their market prices. The three leader brands in the Brazilian beer market, which have been subject to fraud, were modeled as the higher-price class, while the five brands most used for counterfeiting were modeled as the lower-price class. Parameters affecting the paper spray ionization were examined and optimized. The best MS signal stability and intensity was obtained while using the positive ion mode, with PS(+) mass spectra characterized by intense pairs of signals corresponding to sodium and potassium adducts of malto-oligosaccharides. Discrimination was not apparent neither by using visual inspection nor principal component analysis (PCA). However, supervised classification models provided high rates of sensitivity and specificity. A PLS-DA model using full scan mass spectra were improved by variable selection with ordered predictors selection (OPS), providing 100% of reliability rate and reducing the number of variables from 1701 to 60. This model was interpreted by detecting fifteen variables as the most significant VIP (variable importance in projection) scores, which were therefore considered diagnostic ions for this type of beer counterfeit. PMID:27662764

  12. Variable flow -- the quest for system energy efficiency

    SciTech Connect

    Eppelheimer, D.M.

    1996-12-31

    Varying condenser water flow has long been used as a method of controlling head pressure in water-cooled refrigeration systems. This method of head pressure control has been applied successfully on systems with scroll, reciprocating, heli-rotor, and centrifugal compressors. Condenser water flow is altered either by bypassing the condenser via a three-way valve or by throttling flow with a two-way valve. Today, the affordability and potential energy savings of adjustable speed drives makes this the preferred method of varying flow. In the quest for greater energy savings, many designers propose to vary the flow of water through the evaporators of chillers also. This feat is not as easily accomplished as the first. There are system designs that allow variable flow of chilled water at the system level while maintaining constant flow through the chiller evaporator. Yet in spite of the risk and the presence of other variable options, some still wish to vary the flow of chilled water through the evaporator by large proportions. Can it be done? Of course! However, there are a few engineering problems that must be tackled to accomplish this feat. This paper delineates those problems.

  13. Parsing interindividual drug variability: an emerging role for systems pharmacology

    PubMed Central

    Turner, Richard M; Park, B Kevin; Pirmohamed, Munir

    2015-01-01

    There is notable interindividual heterogeneity in drug response, affecting both drug efficacy and toxicity, resulting in patient harm and the inefficient utilization of limited healthcare resources. Pharmacogenomics is at the forefront of research to understand interindividual drug response variability, but although many genotype-drug response associations have been identified, translation of pharmacogenomic associations into clinical practice has been hampered by inconsistent findings and inadequate predictive values. These limitations are in part due to the complex interplay between drug-specific, human body and environmental factors influencing drug response and therefore pharmacogenomics, whilst intrinsically necessary, is by itself unlikely to adequately parse drug variability. The emergent, interdisciplinary and rapidly developing field of systems pharmacology, which incorporates but goes beyond pharmacogenomics, holds significant potential to further parse interindividual drug variability. Systems pharmacology broadly encompasses two distinct research efforts, pharmacologically-orientated systems biology and pharmacometrics. Pharmacologically-orientated systems biology utilizes high throughput omics technologies, including next-generation sequencing, transcriptomics and proteomics, to identify factors associated with differential drug response within the different levels of biological organization in the hierarchical human body. Increasingly complex pharmacometric models are being developed that quantitatively integrate factors associated with drug response. Although distinct, these research areas complement one another and continual development can be facilitated by iterating between dynamic experimental and computational findings. Ultimately, quantitative data-derived models of sufficient detail will be required to help realize the goal of precision medicine. WIREs Syst Biol Med 2015, 7:221–241. doi: 10.1002/wsbm.1302 PMID:25950758

  14. Aerosol mass spectrometry systems and methods

    DOEpatents

    Fergenson, David P.; Gard, Eric E.

    2013-08-20

    A system according to one embodiment includes a particle accelerator that directs a succession of polydisperse aerosol particles along a predetermined particle path; multiple tracking lasers for generating beams of light across the particle path; an optical detector positioned adjacent the particle path for detecting impingement of the beams of light on individual particles; a desorption laser for generating a beam of desorbing light across the particle path about coaxial with a beam of light produced by one of the tracking lasers; and a controller, responsive to detection of a signal produced by the optical detector, that controls the desorption laser to generate the beam of desorbing light. Additional systems and methods are also disclosed.

  15. 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

  16. On the use and abuse of Newton's second law for variable mass problems

    NASA Astrophysics Data System (ADS)

    Plastino, Angel R.; Muzzio, Juan C.

    1992-09-01

    Solution techniques for celestial mechanics problems involving bodies of varying mass are considered analytically, emphasizing the fact that Newton's second law is valid only for fixed-mass bodies. In the restricted three-body problem, for example, it is pointed out that the motion of a body losing mass isotropically is unaffected by this loss. Expressions to be substituted in the cases of accretion or ablation are presented, and several recent works in which Newton's law is misused are discussed.

  17. 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

  18. NCDC mass storage systems and technologies

    NASA Technical Reports Server (NTRS)

    Davis, Dick

    1993-01-01

    National Climatic Data Center (NCDC) data management issues are discussed, such as nature of holdings, history of the site, popularity of data sets, media/technology used for storage, volume distributed per month, mode of distribution, most frequently encountered problems, type of media requested/used, and evolution of media. Current holdings at NCDC are 107.8 terabytes of digital data and about 0.3 terabytes of manuscript data. The nexrad radar system is expected to generate approximately 88 terabytes per year by 1996.

  19. The Effects of Increasing Mass on the Variability of Movement & Segmental Movement Times.

    ERIC Educational Resources Information Center

    Byrne, Connell M. J.; And Others

    The effects of increasing the load of materials to be moved on rapid movement of these materials were measured using two dependent variables. The first analysis involved overall mean movement time (MT) and segmental movement times. The second analysis dealt with movement time variability evidenced by within subject MT and segmental MT standard…

  20. 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.

  1. Adaptive mass expulsion attitude control system

    NASA Technical Reports Server (NTRS)

    Rodden, John J. (Inventor); Stevens, Homer D. (Inventor); Carrou, Stephane (Inventor)

    2001-01-01

    An attitude control system and method operative with a thruster controls the attitude of a vehicle carrying the thruster, wherein the thruster has a valve enabling the formation of pulses of expelled gas from a source of compressed gas. Data of the attitude of the vehicle is gathered, wherein the vehicle is located within a force field tending to orient the vehicle in a first attitude different from a desired attitude. The attitude data is evaluated to determine a pattern of values of attitude of the vehicle in response to the gas pulses of the thruster and in response to the force field. The system and the method maintain the attitude within a predetermined band of values of attitude which includes the desired attitude. Computation circuitry establishes an optimal duration of each of the gas pulses based on the pattern of values of attitude, the optimal duration providing for a minimal number of opening and closure operations of the valve. The thruster is operated to provide gas pulses having the optimal duration.

  2. 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.

  3. Mass Measurement System Using Relay Feedback with Hysteresis

    NASA Astrophysics Data System (ADS)

    Mizuno, Takeshi; Adachi, Takahiro; Takasaki, Masaya; Ishino, Yuji

    Mass measurement using a relay feedback system was studied experimentally. The measurement system has an on-off relay with hysteresis and switches force acting on the object in relation to its velocity. Such nonlinear control induces a limit cycle in the feedback system. The mass of the object is determined from the period of this limit cycle. The apparatus manufactured for experimental study uses two voice coil motors (VCM's), one of which is for driving the object and the other is for generating prescribed disturbances. The effects of system parameters and disturbances on measurement accuracy were examined experimentally.

  4. Odor Sensing System Using Preconcentrator with Variable Temperature

    SciTech Connect

    Isaka, Y; Nakamoto, Takamichi; Moriizumi, T; Grate, Jay W. )

    1999-01-01

    An odor sensing system using QCM gas sensor array and pattern recognition technique is useful to identify various kinds of odors. A preconcentrator with variable temperature is promising to obtain further pattern separation after the appropriate temperature changes, whereas it has been so far used to enhance sensor sensitivity. After the preconcentrator collects the vapors, it is heated so that they can be thermally desorbed. The combination of the preconcentrator with the sensor array enhances the capability of discrimination among vapors since their desorption temperatures depend upon vapor kinds.

  5. A Theorem to Confirm Causal Directions in a Closed System of Five Variables.

    ERIC Educational Resources Information Center

    Nigro, George A.

    The applicability of a mathematical theorem designed to trace causality of a three-variable path that consists of an initial cause variable, an intermediate variable, and a final-effect variable with control over other system variables is evaluated. The formula was used with a horizontal rather than a normal distribution, as had been done in an…

  6. Novel models on fluid's variable thermo-physical properties for extensive study on convection heat and mass transfer

    NASA Astrophysics Data System (ADS)

    Shang, De-Yi; Zhong, Liang-Cai

    2016-04-01

    Our novel models for fluid's variable physical properties are improved and reported systematically in this work for enhancement of theoretical and practical value on study of convection heat and mass transfer. It consists of three models, namely (1) temperature parameter model, (2) polynomial model, and (3) weighted-sum model, respectively for treatment of temperature-dependent physical properties of gases, temperature-dependent physical properties of liquids, and concentration- and temperature-dependent physical properties of vapour-gas mixture. Two related components are proposed, and involved in each model for fluid's variable physical properties. They are basic physic property equations and theoretical similarity equations on physical property factors. The former, as the foundation of the latter, is based on the typical experimental data and physical analysis. The latter is built up by similarity analysis and mathematical derivation based on the former basic physical properties equations. These models are available for smooth simulation and treatment of fluid's variable physical properties for assurance of theoretical and practical value of study on convection of heat and mass transfer. Especially, so far, there has been lack of available study on heat and mass transfer of film condensation convection of vapour-gas mixture, and the wrong heat transfer results existed in widespread studies on the related research topics, due to ignorance of proper consideration of the concentration- and temperature-dependent physical properties of vapour-gas mixture. For resolving such difficult issues, the present novel physical property models have their special advantages.

  7. IRAS observations of Delta Scuti variables - Implications for main-sequence mass loss and an IR period-luminosity relation

    SciTech Connect

    King, J.R. )

    1990-06-01

    The far-infrared detections of Delta Scuti variables in The Bright Star Catalog by the IRAS satellite are investigated; 52 percent of the sample was detected at 12 microns. The 12 micron luminosity is correlated with L(Bol) and ranges from about 3 x 10 to the 31st to about 6 x 10 to the 32nd erg/s. Comparable numbers of Delta Sct variables and A-F nonvariables show infrared excesses in at least one IRAS passband. Further considerations show that contributions to these excesses due to mass loss are minimal. This investigation suggests that the pulsating variables are not losing mass at higher rates than nonvariable A and F stars which themselves do not appear to be losing mass at a rate above an expected level. The existence of a Period-12 micron luminosity relation of small dispersion, quite surprising in light of the uncertainties in these data is reported. It is demonstrated that such relations also exist at the J, H, and K bands. The possibility of using such relations for distance determinations is discussed in light of good distance estimates to three clusters using the P-L relation. 20 refs.

  8. Variability in the Cardiac Venous System of Wistar Rats

    PubMed Central

    Krešáková, Lenka; Purzyc, Halina; Schusterová, Ingrid; Fulton, Benjamin; Maloveská, Marcela; Vdoviaková, Katarina; Kravcová, Zuzanna; Boldižár, Martin

    2015-01-01

    Rats are often used as animal models in experimental cardiology for studying myocardial infarctions and various cardiologic procedures. Currently the cardiac venous system is a target for the delivery of drugs, gene vectors, angiogenetic growth factors, stem cells, and cardioprotective reagents. The purpose of this study was to describe the anatomic configuration and variability of the cardiac venous system in Wistar rats, by using the corrosion cast method and perfusion of colored latex. The distribution of veins in the rat heart disagrees with prior descriptions for other mammals, except mice, which have a similar pattern. Coronary venous drainage in the 36 rats examined consistently involved the left cardiac, left conal, major caudal, right cardiac, and right conal veins. Other veins involved inconsistently included the cranial cardiac vein (58.3% of cases), minor caudal veins (16.7%), conoanastomotic vein (66.7%), and left atrial vein (75%). In 4 cases (11.1%), the collateral veins were located between the left conal and left cardiac veins. In this study, high morphologic variability between cases was manifested by differences in the arrangement, size, mode of opening, and formation of the common root and affected all regions of the heart but primarily the right ventricle. PMID:25651085

  9. Concepts for Variable/Multi-Speed Rotorcraft Drive System

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

    In several recent studies and on-going developments for advanced rotorcraft, the need for variable or multi-speed capable rotors has been raised. A speed change of up to 50 percent has been proposed for future rotorcraft to improve overall vehicle performance. Accomplishing rotor speed changes during operation requires both a rotor that can perform effectively over the operation speed/load range, and a propulsion system that can enable these speed changes. A study has been completed to investigate possible drive system arrangements that can accommodate up to the 50 percent speed change. Several concepts will be presented and evaluated. The most promising configurations will be identified and developed for future testing in a sub-scaled test facility to validate operational capability.

  10. 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

  11. 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.

  12. Goddard Conference on Mass Storage Systems and Technologies, volume 2

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

    Papers and viewgraphs from the conference are presented. 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 discussion topics addressed the evolution of the identifiable unit for processing (file, granule, data set, or some similar object) as data ingestion rates increase dramatically, and the present state of the art in mass storage technology.

  13. 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.

  14. Specialized Gas Chromatography--Mass Spectrometry Systems for Clinical Chemistry.

    ERIC Educational Resources Information Center

    Gochman, Nathan; And Others

    1979-01-01

    A discussion of the basic design and characteristics of gas chromatography-mass spectrometry systems used in clinical chemistry. A comparison of three specific systems: the Vitek Olfax IIA, Hewlett-Packard HP5992, and Du Pont DP-102 are included. (BB)

  15. Satellite masses in the Uranus and Neptune systems

    SciTech Connect

    Greenberg, R.

    1984-10-01

    Satellite masses are derivation with emphasis on implications for bulk densities and albedos is reviewed. In the Uranian system the inner satellites have lower densities and/or higher albedos than the outer ones. However, uncertainties are great enough that all five satellites may have nearly equal densities. In such a case the albedo would decrease with semimajor axis. A more severe constraint is placed on Miranda's mass, and hence on its density and albedo. The recent radiometric value for Triton's diameter, combined with mass determinations, yields a density greater than 4 gm/cm3.

  16. Microscale mass spectrometry systems, devices and related methods

    DOEpatents

    Ramsey, John Michael

    2016-06-21

    Mass spectrometry systems or assemblies therefore include an ionizer that includes at least one planar conductor, a mass analyzer with a planar electrode assembly, and a detector comprising at least one planar conductor. The ionizer, the mass analyzer and the detector are attached together in a compact stack assembly. The stack assembly has a perimeter that bounds an area that is between about 0.01 mm.sup.2 to about 25 cm.sup.2 and the stack assembly has a thickness that is between about 0.1 mm to about 25 mm.

  17. Satellite Masses in the Uranus and Neptune Systems

    NASA Technical Reports Server (NTRS)

    Greenberg, R.

    1984-01-01

    Satellite masses are derivation with emphasis on implications for bulk densities and albedos is reviewed. In the Uranian system the inner satellites have lower densities and/or higher albedos than the outer ones. However, uncertainties are great enough that all five satellites may have nearly equal densities. In such a case the albedo would decrease with semimajor axis. A more severe constraint is placed on Miranda's mass, and hence on its density and albedo. The recent radiometric value for Triton's diameter, combined with mass determinations, yields a density greater than 4 gm/cu cm.

  18. Development of a pressure based vortex-shedding meter: measuring unsteady mass-flow in variable density gases

    NASA Astrophysics Data System (ADS)

    Ford, C. L.; Winroth, M.; Alfredsson, P. H.

    2016-08-01

    An entirely pressure-based vortex-shedding meter has been designed for use in practical time-dependent flows. The meter is capable of measuring mass-flow rate in variable density gases in spite of the fact that fluid temperature is not directly measured. Unlike other vortex meters, a pressure based meter is incredibly robust and may be used in industrial type flows; an environment wholly unsuitable for hot-wires for example. The meter has been tested in a number of static and dynamic flow cases, across a range of mass-flow rates and pressures. The accuracy of the meter is typically better than about 3% in a static flow and resolves the fluctuating mass-flow with an accuracy that is better than or equivalent to a hot-wire method.

  19. Coupled effect of flow variability and mass transfer on contaminant transport and attenuation in groundwater

    NASA Astrophysics Data System (ADS)

    Cvetkovic, Vladimir; Fiori, Aldo; Dagan, Gedeon

    2016-04-01

    The driving mechanism of contaminant transport in aquifers is groundwater flow, which is controlled by boundary conditions and heterogeneity of hydraulic properties. In this work we show how hydrodynamics and mass transfer can be combined in a general analytical manner to derive a physically-based (or process-based) residence time distribution for a given integral scale of the hydraulic conductivity; the result can be applied for a broad class of linear mass transfer processes. The derived tracer residence time distribution is a transfer function with parameters to be inferred from combined field and laboratory measurements. It is scalable relative to the correlation length and applicable for an arbitrary statistical distribution of the hydraulic conductivity. Based on the derived residence time distribution, the coefficient of variation and skewness of contaminant residence time are illustrated assuming a log-normal hydraulic conductivity distribution and first-order mass transfer. We show that for a low Damkohler number the coefficient of variation is more strongly influenced by mass transfer than by heterogeneity, whereas skewness is more strongly influenced by heterogeneity. The derived physically-based residence time distribution for solute transport in heterogeneous aquifers is particularly useful for studying natural attenuation of contaminants. We illustrate the relative impacts of high heterogeneity and a generalised (non-Fickian) multi-rate mass transfer on natural attenuation defined as contaminant mass loss from injection to a downstream compliance boundary.

  20. Using sorted invariant mass variables to evade combinatorial ambiguities in cascade decays

    DOE PAGESBeta

    Kim, Doojin; Matchev, Konstantin T.; Park, Myeonghun

    2016-02-19

    The classic method for mass determination in a SUSY-like cascade decay chain relies on measurements of the kinematic endpoints in the invariant mass distributions of suitable collections of visible decay products. However, the procedure is complicated by combinatorial ambiguities: e.g., the visible final state particles may be indistinguishable (as in the case of QCD jets), or one may not know the exact order in which they are emitted along the decay chain. In order to avoid such combinatorial ambiguities, we propose to treat the nal state particles fully democratically and consider the sorted set of the invariant masses of allmore » possible partitions of the visible particles in the decay chain. In particular, for a decay to N visible particles, one considers the sorted sets of all possible n-body invariant mass combinations (2≤ n≤ N) and determines the kinematic endpoint m(n,r)max of the distribution of the r-th largest n-body invariant mass m(n,r) for each possible value of n and r. For the classic example of a squark decay in supersymmetry, we provide analytical formulas for the interpretation of these endpoints in terms of the underlying physical masses. We point out that these measurements can be used to determine the structure of the decay topology, e.g., the number and position of intermediate on-shell resonances.« less

  1. The high-amplitude δ Scuti variable CY Aqr is probably a triple system

    NASA Astrophysics Data System (ADS)

    Fang, Wei-Jing; Luo, Zhi-Quan; Zhang, Xiao-Bin; Deng, Li-Cai; Wang, Kun; Luo, Yang-Ping; Pan, Yang; Peng, Yin-Jiang

    2016-06-01

    Data representing 864 times of light maxima of the high-amplitude δ Scuti star CY Aqr were collected from the literature, based on which, long-term period changes of the variable star were investigated. A revised period and new ephemerides were given for the pulsating star. Remarkable cyclic variations were found in the O - C residuals which can be attributed to the light-time effects due to probable unseen components of the object. By using Kopal's method, the orbital parameters of the supposed component stars were derived. The solution suggests that CY Aqr is very probably in a triple system orbited eccentrically by two low-mass companions with periods of 54.2 and 47.3 yr. The lower limits on masses were estimated as 0.04 M ⊙ and 0.02 M ⊙, respectively, for the two hidden companions.

  2. A Model of Cataclysmic Variable Systems with the Particle Simulation Code VINE

    NASA Astrophysics Data System (ADS)

    Kreidberg, Laura; Wood, M.; Wetzstein, M.

    2010-01-01

    In this poster we present a preliminary model of cataclysmic variables, close binary systems consisting of a white dwarf primary and a lower mass main-sequence secondary star. Mass transfer from the secondary results in the formation of an accretion disk surrounding the primary. We modeled the accretion disk with the method of smoothed particle hydrodynamics (SPH), as implemented in the public domain code VINE, which we modified for this project. We incorporated VINE's dynamic smoothing lengths and time-varying viscosity to create a more physical model as compared to pre-existing simulations. This project was funded by a partnership between the National Science Foundation (NSF AST-0552798), Research Experiences for Undergraduates (REU), and the Department of Defense (DoD) ASSURE (Awards to Stimulate and Support Undergraduate Research Experiences) programs.

  3. Performance evaluation of mass storage systems for scientific databases

    SciTech Connect

    Segev, A. |; Seshadri, S.; Rotem, D.

    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.

  4. 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.

  5. 454-Pyrosequencing Reveals Variable Fungal Diversity Across Farming Systems

    PubMed Central

    Kazeeroni, Elham A.; Al-Sadi, Abdullah M.

    2016-01-01

    Oasis farming system is common in some parts of the world, especially in the Arabian Peninsula and several African countries. In Oman, the farming system in the majority of farms follows a semi-oasis farming (SOF) system, which is characterized by growing multiple crops mainly for home consumption, but also for local market. This study was conducted to investigate fungal diversity using pyrosequencing approach in soils from a farm utilizing a SOF system which is cultivated with date palms, acid limes and cucumbers. Fungal diversity from this farm was compared to that from an organic farm (OR) growing cucumbers and tomatoes. Fungal diversity was found to be variable among different crops in the same farm. The observed OTUs, Chao1 richness estimates and Shannon diversity values indicated that soils from date palms and acid limes have higher fungal diversity compared to soil from cucumbers (SOF). In addition, they also indicated that the level of fungal diversity is higher in the rhizosphere of cucumbers grown in OR compared to SOF. Ascomycota was the most dominant phylum in most of the samples from the OR and SOF farms. Other dominant phyla are Microsporidia, Chytridiomycota, and Basidiomycota. The differential level of fungal diversity within the SOF could be related to the variation in the cultural practices employed for each crop. PMID:27014331

  6. 454-Pyrosequencing Reveals Variable Fungal Diversity Across Farming Systems.

    PubMed

    Kazeeroni, Elham A; Al-Sadi, Abdullah M

    2016-01-01

    Oasis farming system is common in some parts of the world, especially in the Arabian Peninsula and several African countries. In Oman, the farming system in the majority of farms follows a semi-oasis farming (SOF) system, which is characterized by growing multiple crops mainly for home consumption, but also for local market. This study was conducted to investigate fungal diversity using pyrosequencing approach in soils from a farm utilizing a SOF system which is cultivated with date palms, acid limes and cucumbers. Fungal diversity from this farm was compared to that from an organic farm (OR) growing cucumbers and tomatoes. Fungal diversity was found to be variable among different crops in the same farm. The observed OTUs, Chao1 richness estimates and Shannon diversity values indicated that soils from date palms and acid limes have higher fungal diversity compared to soil from cucumbers (SOF). In addition, they also indicated that the level of fungal diversity is higher in the rhizosphere of cucumbers grown in OR compared to SOF. Ascomycota was the most dominant phylum in most of the samples from the OR and SOF farms. Other dominant phyla are Microsporidia, Chytridiomycota, and Basidiomycota. The differential level of fungal diversity within the SOF could be related to the variation in the cultural practices employed for each crop. PMID:27014331

  7. 454-Pyrosequencing Reveals Variable Fungal Diversity Across Farming Systems.

    PubMed

    Kazeeroni, Elham A; Al-Sadi, Abdullah M

    2016-01-01

    Oasis farming system is common in some parts of the world, especially in the Arabian Peninsula and several African countries. In Oman, the farming system in the majority of farms follows a semi-oasis farming (SOF) system, which is characterized by growing multiple crops mainly for home consumption, but also for local market. This study was conducted to investigate fungal diversity using pyrosequencing approach in soils from a farm utilizing a SOF system which is cultivated with date palms, acid limes and cucumbers. Fungal diversity from this farm was compared to that from an organic farm (OR) growing cucumbers and tomatoes. Fungal diversity was found to be variable among different crops in the same farm. The observed OTUs, Chao1 richness estimates and Shannon diversity values indicated that soils from date palms and acid limes have higher fungal diversity compared to soil from cucumbers (SOF). In addition, they also indicated that the level of fungal diversity is higher in the rhizosphere of cucumbers grown in OR compared to SOF. Ascomycota was the most dominant phylum in most of the samples from the OR and SOF farms. Other dominant phyla are Microsporidia, Chytridiomycota, and Basidiomycota. The differential level of fungal diversity within the SOF could be related to the variation in the cultural practices employed for each crop.

  8. Low-Mass, Low-Power Hall Thruster System

    NASA Technical Reports Server (NTRS)

    Pote, Bruce

    2015-01-01

    NASA is developing an electric propulsion system capable of producing 20 mN thrust with input power up to 1,000 W and specific impulse ranging from 1,600 to 3,500 seconds. The key technical challenge is the target mass of 1 kg for the thruster and 2 kg for the power processing unit (PPU). In Phase I, Busek Company, Inc., developed an overall subsystem design for the thruster/cathode, PPU, and xenon feed system. This project demonstrated the feasibility of a low-mass power processing architecture that replaces four of the DC-DC converters of a typical PPU with a single multifunctional converter and a low-mass Hall thruster design employing permanent magnets. In Phase II, the team developed an engineering prototype model of its low-mass BHT-600 Hall thruster system, with the primary focus on the low-mass PPU and thruster. The goal was to develop an electric propulsion thruster with the appropriate specific impulse and propellant throughput to enable radioisotope electric propulsion (REP). This is important because REP offers the benefits of nuclear electric propulsion without the need for an excessively large spacecraft and power system.

  9. Mass

    SciTech Connect

    Quigg, Chris

    2007-12-05

    In the classical physics we inherited from Isaac Newton, mass does not arise, it simply is. The mass of a classical object is the sum of the masses of its parts. Albert Einstein showed that the mass of a body is a measure of its energy content, inviting us to consider the origins of mass. The protons we accelerate at Fermilab are prime examples of Einsteinian matter: nearly all of their mass arises from stored energy. Missing mass led to the discovery of the noble gases, and a new form of missing mass leads us to the notion of dark matter. Starting with a brief guided tour of the meanings of mass, the colloquium will explore the multiple origins of mass. We will see how far we have come toward understanding mass, and survey the issues that guide our research today.

  10. Targeted Multiplex Imaging Mass Spectrometry with Single Chain Fragment Variable (scfv) Recombinant Antibodies

    NASA Astrophysics Data System (ADS)

    Thiery, Gwendoline; Mernaugh, Ray L.; Yan, Heping; Spraggins, Jeffrey M.; Yang, Junhai; Parl, Fritz F.; Caprioli, Richard M.

    2012-10-01

    Recombinant scfv antibodies specific for CYP1A1 and CYP1B1 P450 enzymes were combined with targeted imaging mass spectrometry to simultaneously detect the P450 enzymes present in archived, paraffin-embedded, human breast cancer tissue sections. By using CYP1A1 and CYP1B1 specific scfv, each coupled to a unique reporter molecule (i.e., a mass tag) it was possible to simultaneously detect multiple antigens within a single tissue sample with high sensitivity and specificity using mass spectrometry. The capability of imaging multiple antigens at the same time is a significant advance that overcomes technical barriers encountered when using present day approaches to develop assays that can simultaneously detect more than a single antigen in the same tissue sample.

  11. Optimization of neural networks using variable structure systems.

    PubMed

    Mohseni, Seyed Alireza; Tan, Ai Hui

    2012-12-01

    This paper proposes a new mixed training algorithm consisting of error backpropagation (EBP) and variable structure systems (VSSs) to optimize parameter updating of neural networks. For the optimization of the number of neurons in the hidden layer, a new term based on the output of the hidden layer is added to the cost function as a penalty term to make optimal use of hidden units related to weights corresponding to each unit in the hidden layer. VSS is used to control the dynamic model of the training process, whereas EBP attempts to minimize the cost function. In addition to the analysis of the imposed dynamics of the EBP technique, the global stability of the mixed training methodology and constraints on the design parameters are considered. The advantages of the proposed technique are guaranteed convergence, improved robustness, and lower sensitivity to initial weights of the neural network.

  12. A variable inductor circuit design for inductive energy storage systems

    SciTech Connect

    Andrianov, V.V.; Baev, V.P.; Kazantsev, N.A.; Ostashev, V.E.; Parizh, M.B.; Sheinkman, V.S. )

    1990-05-01

    A circuit design for matching an inductive energy storage to a utility grid and a complex load (railgun accelerator) is discussed. A circuit design is suggested for control of the discharge current to provide effective transfer of the energy stored in the inductive storage. It is shown that this circuit design, with a variable winding inductance, provides energy transmission control and allows both a higher efficiency of energy transfer and arrangement of a quick response reserve power source to maintain high-current energy transmission. The arrangement discussed may be used to provide matching of the energy user's load current to the energy storage's initial current which is determined either by the possibility of energy accumulation in the system or by the power supply source's current.

  13. 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.

  14. 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.

  15. 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.

  16. Mass sensing based on a circuit cavity electromechanical system

    NASA Astrophysics Data System (ADS)

    Jiang, Cheng; Chen, Bin; Li, Jin-Jin; Zhu, Ka-Di

    2011-10-01

    We present a scheme for mass sensing based on a circuit cavity electromechanical system where a free-standing, flexible aluminium membrane is capacitively coupled to a superconducting microwave cavity. Integration with the microwave cavity enables capacitive readout of the mechanical resonance directly on the chip. A microwave pump field and a second probe field are simultaneously applied to the cavity. The accreted mass landing on the membrane can be measured conveniently by tracking the mechanical resonance frequency shifts due to mass changes in the probe transmission spectrum. The mass responsivity for the membrane is 0.72 Hz/ag and we demonstrate that frequency shifts induced by adsorption of one hundred 1587 bp DNA molecules can be well resolved in the probe transmission spectrum.

  17. Variable Curvature Mirrors for ELT Laser Guide Star refocusing systems

    NASA Astrophysics Data System (ADS)

    Challita, Zalpha; Hugot, Emmanuel; Ferrari, Marc; Madec, Fabrice; Le Mignant, David; Cuby, Jean-Gabriel

    2011-09-01

    The future generation of Extremely Large Telescopes will require a complex combination of technologies for adaptive optics (AO) systems assisted by laser guide stars (LGS). In this context, LGS defocusing is one of the system issues that can be tackled using active refocusing mirrors such as Variable Curvature Mirrors (VCM). Indeed, the distance from the LGS spot to the telescope pupil ranges from about 80 to 200 km, depending on the Sodium layer altitude and the elevation of the telescope, and induces a large defocusing at the LGS wave-front sensor focal plane. To compensate for that, we propose an original concept including a VCM specifically designed to keep a focused spot on the wave-front sensor: the mirror is made of a thin meniscus bend using a pressure applied on its back face. Due to the large defocusing, the LGS-VCM must be able to change its shape from F/12.5 to F/5, leading to more than 1 mm sag. The VCM benefits of a specific shape with a variable radial thickness distribution, allowing keeping an optical quality better than λ/5 over this very large range of deformation. The work presented here details the analytical development leading to the specific geometry of the active component, the results of finite element analysis and the expected performances in terms of surface error versus the range of refocalisation. Two prototypes have been manufactured to compare the real behaviour of the mirror and the simulations data. Results obtained on the prototypes show that the deformation of the VCM is very close to the simulation, and leads to a realistic concept.

  18. High frequency analysis of a plate carrying a concentrated nonlinear spring-mass system

    NASA Astrophysics Data System (ADS)

    Culver, Dean; Dowell, Earl

    2016-09-01

    Examining the behavior of dynamical systems with many degrees of freedom undergoing random excitation at high frequency often requires substantial computation. These requirements are even more stringent for nonlinear systems. One approach for describing linear systems, Asymptotic Modal Analysis (AMA), has been extended to nonlinear systems in this paper. A prototypical system, namely a thin plate carrying a concentrated hardening cubic spring-mass, is explored. The study focuses on the response of three principal variables to random, frequency-bounded excitation: the displacement of the mounting location of the discrete spring-mass, the relative displacement of the discrete mass to this mounting location, and the absolute displacement of the discrete mass. The results indicate that extending AMA to nonlinear systems for input frequency bands containing a large number of modes is feasible. Several advantageous properties of nonlinear AMA are found, and an additional reduced frequency-domain modal method, Dominance-Reduced Classical Modal Analysis (DRCMA), is proposed that is intermediate in accuracy and the cost of computation between AMA and Classical Modal Analysis (CMA).

  19. Electromagnetic variable degrees of freedom actuator systems and methods

    DOEpatents

    Montesanti, Richard C.; Trumper, David L.; Kirtley, Jr., James L.

    2009-02-17

    The present invention provides a variable reluctance actuator system and method that can be adapted for simultaneous rotation and translation of a moving element by applying a normal-direction magnetic flux on the moving element. In a beneficial example arrangement, the moving element includes a swing arm that carries a cutting tool at a set radius from an axis of rotation so as to produce a rotary fast tool servo that provides a tool motion in a direction substantially parallel to the surface-normal of a workpiece at the point of contact between the cutting tool and workpiece. An actuator rotates a swing arm such that a cutting tool moves toward and away from a mounted rotating workpiece in a controlled manner in order to machine the workpiece. Position sensors provide rotation and displacement information for a swing arm to a control system. A control system commands and coordinates motion of the fast tool servo with the motion of a spindle, rotating table, cross-feed slide, and in feed slide of a precision lathe.

  20. VARIABLE BOUND-SITE CHARGING CONTRIBUTIONS TO SURFACE COMPLEXATION MASS ACTION EXPRESSIONS

    EPA Science Inventory

    One and two pK models of surface complexation reactions between reactive surface sites (>SOH) and the proton (H+) use mass action expressions of the form: Ka={[>SOHn-1z-1]g>SOH(0-1)aH+EXP(-xeY/kT)}/{[>SOHnz]g>SOH(n)} where Ka=the acidity constant, [ ]=reactive species concentrati...

  1. CORONAL MASS EJECTIONS AS A MECHANISM FOR PRODUCING IR VARIABILITY IN DEBRIS DISKS

    SciTech Connect

    Osten, Rachel; Livio, Mario; Lubow, Steve; Pringle, J. E.; Soderblom, David; Valenti, Jeff

    2013-03-10

    Motivated by recent observations of short-timescale variations in the infrared emission of circumstellar disks, we propose that coronal mass ejections can remove dust grains on timescales as short as a few days. Continuous monitoring of stellar activity, coupled with infrared observations, can place meaningful constraints on the proposed mechanism.

  2. Geomorphological characteristics and variability of Holocene mass-transport complexes, St. Lawrence River Estuary, Canada

    NASA Astrophysics Data System (ADS)

    Pinet, Nicolas; Brake, Virginia; Campbell, Calvin; Duchesne, Mathieu J.

    2015-01-01

    Recently acquired multibeam bathymetry data are used to investigate seafloor instability features along a 310 km-long segment of the St. Lawrence River Estuary. The analysis of this dataset indicates that submarine slides occur over a much larger area than previously recognized and that Holocene sediments are reworked by mass-transport along significant portions of both the northwest and southeast margins of the Laurentian Channel. In the surveyed area, 96 individual mass-transport complexes (MTCs) were identified representing 13% of the seabed. MTCs vary in area from less than 1 km2 to more than 40 km2 and exhibit various geomorphological signatures. Qualitative observation reveals an apparent disparity between MTCs that remain coherent and those that disintegrate during downslope transport evolving into a blocky morphological signature. For all MTCs, morphological parameters have been measured (area, length, and height) or calculated (slope and roughness). This quantitative analysis provides a unique opportunity to study these parameters in a statistically significant and homogeneous dataset located in a relatively small area that experienced a similar Quaternary history. In many cases, mass transport events appear to initiate in the vicinity of steep bedrock walls located along some segments of the estuary. The timing of mass-transport events was not constrained during this study. However, the fact that the region hosts the Charlevoix seismic zone, the most tectonically active area in eastern Canada, strongly suggests that earthquakes acted as a trigger for submarine landsliding.

  3. Fermilab's multi-petabyte scalable mass storage system

    SciTech Connect

    Oleynik, Gene; Alcorn, Bonnie; Baisley, Wayne; Bakken, Jon; Berg, David; Berman, Eileen; Huang, Chih-Hao; Jones, Terry; Kennedy, Robert D.; Kulyavtsev, Alexander; Moibenko, Alexander; Perelmutov, Timur; Petravick, Don; Podstavkov, Vladimir; Szmuksta, George; Zalokar, Michael; /Fermilab

    2005-01-01

    Fermilab provides a multi-Petabyte scale mass storage system for High Energy Physics (HEP) Experiments and other scientific endeavors. We describe the scalability aspects of the hardware and software architecture that were designed into the Mass Storage System to permit us to scale to multiple petabytes of storage capacity, manage tens of terabytes per day in data transfers, support hundreds of users, and maintain data integrity. We discuss in detail how we scale the system over time to meet the ever-increasing needs of the scientific community, and relate our experiences with many of the technical and economic issues related to scaling the system. Since the 2003 MSST conference, the experiments at Fermilab have generated more than 1.9 PB of additional data. We present results on how this system has scaled and performed for the Fermilab CDF and D0 Run II experiments as well as other HEP experiments and scientific endeavors.

  4. Impact of Climatic Variability on Atmospheric Mass Distribution and GRACE-Derived Gravity Fields

    NASA Technical Reports Server (NTRS)

    Salstein, David A.; Rosen, Richard D.; Ponte, Rui M.; Frey, Herbert (Technical Monitor)

    2003-01-01

    During the period we calculated the atmospheric data sets related to its mass and angular momentum distribution. For mass, we determined the various harmonics from the NCEP-NCAR reanalysis, especially the low-order harmonics that are useful in studying the gravitation distribution as will be determined from the GRACE mission. Atmospheric mass is also related to the atmospheric loading on the solid Earth; we cooperated with scientists who needed the atmospheric mass information for understanding its contributions to the overall loading, necessary for vertical and horizontal coordinate estimation. We calculated atmospheric angular momentum from the NCEP-NCAR reanalyses and 4 operational meteorological centers, based on the motion (wind) terms and the mass (surface pressure) terms. These are associated with motions of the planet, including its axial component causing changes in the length of day, more related to the winds, and the equatorial component related to motions of the pole, more related to the mass. Tasks related to the ocean mass and angular momentum were added to the project as well. For these we have noted the ocean impact on motions of the pole as well as the torque mechanisms that relate the transfer of angular momentum between oceans and solid earth. The activities of the project may be summarized in the following first manuscript written in December 2002, for a symposium that Dr. Salstein attended on Geodynamics. We have continued to assess ocean angular momentum (OAM) quantities derived from bottom pressure and velocity fields estimated with our finite-difference barotropic (single layer) model. Three years of output (1993-95) from a run without any data constraints was compared to output from a corresponding run that was constrained by altimeter data using a Kalman filter and smoother scheme. Respective OAM time series were combined with corresponding atmospheric series and compared to observed polar motion. The constrained OAM series provided

  5. Short-term variability and mass loss in Be stars. I. BRITE satellite photometry of η and μ Centauri

    NASA Astrophysics Data System (ADS)

    Baade, D.; Rivinius, Th.; Pigulski, A.; Carciofi, A. C.; Martayan, Ch.; Moffat, A. F. J.; Wade, G. A.; Weiss, W. W.; Grunhut, J.; Handler, G.; Kuschnig, R.; Mehner, A.; Pablo, H.; Popowicz, A.; Rucinski, S.; Whittaker, G.

    2016-04-01

    Context. Empirical evidence for the involvement of nonradial pulsations (NRPs) in the mass loss from Be stars ranges from (i) a singular case (μ Cen) of repetitive mass ejections triggered by multi-mode beating to (ii) several photometric reports about enormous numbers of pulsation modes that suddenly appear during outbursts and on to (iii) effective single-mode pulsators. Aims: The purpose of this study is to develop a more detailed empirical description of the star-to-disk mass transfer and to check the hypothesis that spates of transient nonradial pulsation modes accompany and even drive mass-loss episodes. Methods: The BRITE Constellation of nanosatellites was used to obtain mmag photometry of the Be stars η and μ Cen. Results: In the low-inclination star μ Cen, light pollution by variable amounts of near-stellar matter prevented any new insights into the variability and other properties of the central star. In the equator-on star η Cen, BRITE photometry and Heros echelle spectroscopy from the 1990s reveal an intricate clockwork of star-disk interactions. The mass transfer is modulated with the frequency difference of two NRP modes and an amplitude three times as large as the amplitude sum of the two NRP modes. This process feeds a high-amplitude circumstellar activity running with the incoherent and slightly lower so-called Štefl frequency. The mass-loss-modulation cycles are tightly coupled to variations in the value of the Štefl frequency and in its amplitude, albeit with strongly drifting phase differences. Conclusions: The observations are well described by the decomposition of the mass loss into a pulsation-related engine in the star and a viscosity-dominated engine in the circumstellar disk. Arguments are developed that large-scale gas-circulation flows occur at the interface. The propagation rates of these eddies manifest themselves as Štefl frequencies. Bursts in power spectra during mass-loss events can be understood as the noise inherent to

  6. High Performance Variable Speed Drive System and Generating System with Doubly Fed Machines

    NASA Astrophysics Data System (ADS)

    Tang, Yifan

    Doubly fed machines are another alternative for variable speed drive systems. The doubly fed machines, including doubly fed induction machine, self-cascaded induction machine and doubly excited brushless reluctance machine, have several attractive advantages for variable speed drive applications, the most important one being the significant cost reduction with a reduced power converter rating. With a better understanding, improved machine design, flexible power converters and innovated controllers, the doubly fed machines could favorably compete for many applications, which may also include variable speed power generations. The goal of this research is to enhance the attractiveness of the doubly fed machines for both variable speed drive and variable speed generator applications. Recognizing that wind power is one of the favorable clean, renewable energy sources that can contribute to the solution to the energy and environment dilemma, a novel variable-speed constant-frequency wind power generating system is proposed. By variable speed operation, energy capturing capability of the wind turbine is improved. The improvement can be further enhanced by effectively utilizing the doubly excited brushless reluctance machine in slip power recovery configuration. For the doubly fed machines, a stator flux two -axis dynamic model is established, based on which a flexible active and reactive power control strategy can be developed. High performance operation of the drive and generating systems is obtained through advanced control methods, including stator field orientation control, fuzzy logic control and adaptive fuzzy control. System studies are pursued through unified modeling, computer simulation, stability analysis and power flow analysis of the complete drive system or generating system with the machine, the converter and the control. Laboratory implementations and tested results with a digital signal processor system are also presented.

  7. 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.

  8. Deep, Low Mass Ratio Overcontact Binary Systems. V. The Lowest Mass Ratio Binary V857 Herculis

    NASA Astrophysics Data System (ADS)

    Qian, S.-B.; Zhu, L.-Y.; Soonthornthum, B.; Yuan, J.-Z.; Yang, Y.-G.; He, J.-J.

    2005-09-01

    Charge-coupled device (CCD) photometric light curves in the B, V, and R bands of the complete eclipsing binary star V857 Her are presented. It is shown that the light curves of the W UMa-type binary are symmetric and of A type according to Binnendijk's classification. Our four epochs of light minimum along with others compiled from the literature were used to revise the period and study the period change. Weak evidence indicates that the orbital period of V857 Her may show a continuous increase at a rate of dP/dt=+2.90×10-7 days yr-1. The photometric parameters of the system were determined with the 2003 version of the Wilson-Devinney code. It is shown that V857 Her is a deep overcontact binary system with f=83.8%+/-5.1%. The derived mass ratio of q=0.06532+/-0.0002 suggests that it has the lowest mass ratio among overcontact binary systems. As the orbital period increases, the decrease of the mass ratio will cause it to evolve into a single rapidly rotating star when it meets the more familiar criterion that the orbital angular momentum be less than 3 times the total spin angular momentum. To understand the evolutionary state of the system, long-term photometric monitoring and spectroscopic observations will be required.

  9. Resonance Ionization Mass Spectrometry System for Measurement of Environmental Samples

    NASA Astrophysics Data System (ADS)

    Pibida, L.; McMahon, C. A.; Nörtershäuser, W.; Bushaw, B. A.

    2002-10-01

    A resonance ionization mass spectrometry (RIMS) system has been developed at the National Institute of Standards and Technology (NIST) for sensitive and selective determination of radio-cesium in the environment. The overall efficiency was determined to be 4×10-7 with a combined (laser and mass spectrometer) selectivity of 108 for both 135Cs and 137Cs with respect to 133Cs. RIMS isotopic ratio measurements of 135Cs/ 137Cs were performed on a nuclear fuel burn-up sample and compared to measurements on a similar system at Pacific Northwest National Laboratory (PNNL) and to conventional thermal ionization mass spectrometry (TIMS). Results of preliminary RIMS investigations on a freshwater lake sediment sample are also discussed.

  10. Body mass index and other anthropometric variables in children with sickle cell anaemia

    PubMed Central

    Odetunde, Odutola Israel; Chinawa, Josephat Maduabuchi; Achigbu, Kingsley Ihedioha; Achigbu, Eberechukwu O

    2016-01-01

    Objectives: The objectives of this study were to determine the anthropometric variables of children with sickle cell anaemia and comparing it with those with normal haemoglobin genotype. Methods: A cross sectional study of anthropometric measurements was conducted over a period of six months. Children with sickle cell anaemia in steady state aged between 6-20 years were recruited. Nutritional assessment was done using anthropometrical variables. Data were analyzed using the Statistical Package for Social Sciences program (SPSS), version 20. Results: The sickle cell patients comprised of 20 males and 20 females. There were an equal number of controls with an equal male to female ratio of 1:1. Forty eight percent (19) of the children with sickle cell anemia were underweight (< 5th %ile) and this is statistically significant. χ2=18.02 and p=0.000. When compared with subjects with normal haemoglobin genotype only five of them (13%) were underweight. χ2=10.286 and p=0.001. The controls weighed significantly more than the HbSS patients and also had significantly larger body surface compared to the HbSS population (P<0.05). Conclusion: BMI and other anthropometric variables among children with sickle cell anemia were low when compared with children with normal Haemoglobin genotype. PMID:27182236

  11. Viewing Events in the Center-of-Mass System

    NASA Astrophysics Data System (ADS)

    Ruby, Lawrence

    2010-02-01

    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 energy must be supplied to make the reaction proceed. A typical situation is given by the equation A + B → C + D + Q, (1) where particles A, B, C, and D are expressed in terms of the energy-equivalent of the particle masses, according to the Einstein relation E = mc2, and where Q is a negative energy quantity, corresponding to the excess of mass of (C + D) over that of (A + B). Equation (1) is just an alternate statement of the conservation of total energy. Typically, in the lab system (L), energy is supplied as kinetic energy "T" of particle A, and particle B is at rest. Thus, to conserve momentum, particles C and D must compensate for the momentum corresponding to T. Often, it is desirable to know the minimum value of T that will conserve both energy and momentum, i.e., the threshold value of T, known as Tth, that will just allow the reaction to proceed. At threshold, the particles C and D will have their minimum possible kinetic energies. In the center-of-mass system of coordinates (Z) in which the input momentum is zero, at threshold, the products C and D are each stationary, and this requirement will allow us to calculate the corresponding Tth in the lab system (L). The Z system is often termed the "center-of-mass" system, but it is more properly termed the "zero-momentum" system.

  12. Study of the triple-mass Tethered Satellite System under aerodynamic drag and J2 perturbations

    NASA Astrophysics Data System (ADS)

    Razzaghi, Pourya; Assadian, Nima

    2015-11-01

    The dynamics of multi-tethered satellite formations consisting of three masses are studied in this paper. The triple-mass triple-tethered satellite system is modeled under the low Earth orbit perturbations of drag and Earth's oblateness and its equilibrium conditions are derived. It is modeled as three equal end-masses connected by a uniform-mass straight tether. The lengths of tethers are supposed to be constant and in this manner the angles of the plane consisting the masses are taken as the state variables of the system. The governing equations of motion are derived using Lagrangian approach. The aerodynamic drag perturbation is expressed as an external non-conservative force and the Earth oblateness (J2 perturbation) is considered as a term of potential energy. The equilibrium conditions of this system are found and their stability is investigated through the linear stability theory. Then, the results are verified by using a nonlinear simulation for three types of equilibrium conditions.

  13. Advanced Life Support Equivalent System Mass Guidelines Document

    NASA Technical Reports Server (NTRS)

    Levri, Julie; Fisher, John W.; Jones, Harry W.; Drysdale, Alan E.; Ewert, Michael K.; Hanford, Anthony J.; Hogan, John A.; Joshi, Jitendri, A.; Vaccari, David A.

    2003-01-01

    This document is a viewgraph presentation which provides guidelines for performing an Equivalent System Mass (ESM) evaluation for trade study purposes. The document: 1) Defines ESM; 2) Explains how to calculate ESM; 3) Discusses interpretation of ESM results. The document is designed to provide detailed instructive material for researchers who are performing ESM evaluations for the first time.

  14. 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.

  15. A common mass scaling for satellite systems of gaseous planets.

    PubMed

    Canup, Robin M; Ward, William R

    2006-06-15

    The Solar System's outer planets that contain hydrogen gas all host systems of multiple moons, which notably each contain a similar fraction of their respective planet's mass (approximately 10(-4)). This mass fraction is two to three orders of magnitude smaller than that of the largest satellites of the solid planets (such as the Earth's Moon), and its common value for gas planets has been puzzling. Here we model satellite growth and loss as a forming giant planet accumulates gas and rock-ice solids from solar orbit. We find that the mass fraction of its satellite system is regulated to approximately 10(-4) by a balance of two competing processes: the supply of inflowing material to the satellites, and satellite loss through orbital decay driven by the gas. We show that the overall properties of the satellite systems of Jupiter, Saturn and Uranus arise naturally, and suggest that similar processes could limit the largest moons of extrasolar Jupiter-mass planets to Moon-to-Mars size. PMID:16778883

  16. Mass-resolving charge-exchange system on PDX

    SciTech Connect

    Davis, S.L.; Mueller, D.; Keane, C.J.

    1982-10-01

    The PDX charge-exchange system is comprised of four, ten channel, mass-resolved, charge-exchange analyzers. Each analyzer is constructed with parallel electric and magnetic fields and is calibrated over an energy range of 0.5 to 40 keV. The mass rejection between hydrogen and deuterium has been measured as better than 1000 to 1. For ohmic heated discharges the system can provide single shot radial ion temperature profiles (4 point) with 1 msec time resolution. For neutral beam heated discharges complete radial and temporal profiles can be obtained in 2 to 4 shots. The system is also equipped with a vertically aimed diagnostic neutral beam to allow local ion-energy distribution measurements. This report describes the analyzer system and its calibration, and presents results from ohmic and neutral beam heated discharges.

  17. 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.

  18. Variable-Tension-Cord Suspension/Vibration-Isolation System

    NASA Technical Reports Server (NTRS)

    Villemarette, Mark L.; Boston, Joshua; RInks, Judith; Felice, Pat; Stein, Tim; Payne, Patrick

    2006-01-01

    A system for mechanical suspension and vibration isolation of a machine or instrument is based on the use of Kevlar (or equivalent aromatic polyamide) cord held in variable tension between the machine or instrument and a surrounding frame. The basic concept of such a tensioned-cord suspension system (including one in which the cords are made of aromatic polyamide fibers) is not new by itself; what is new here is the additional provision for adjusting the tension during operation to optimize vibration- isolation properties. In the original application for which this system was conceived, the objective is to suspend a reciprocating cryocooler aboard a space shuttle and to prevent both (1) transmission of launch vibrations to the cryocooler and (2) transmission of vibrations from the cryocooler to samples in a chamber cooled by the cryocooler. The basic mechanical principle of this system can also be expected to be applicable to a variety of other systems in which there are requirements for cord suspension and vibration isolation. The reciprocating cryocooler of the original application is a generally axisymmetric object, and the surrounding frame is a generally axisymmetric object with windows (see figure). Two cords are threaded into a spoke-like pattern between attachment rings on the cryocooler, holes in the cage, and cord-tension- adjusting assemblies. Initially, the cord tensions are adjusted to at least the level necessary to suspend the cryocooler against gravitation. Accelerometers for measuring vibrations are mounted (1) on the cold tip of the cryocooler and (2) adjacent to the cage, on a structure that supports the cage. During operation, a technician observes the accelerometer outputs on an oscilloscope while manually adjusting the cord tensions in an effort to minimize the amount of vibration transmitted to and/or from the cryocooler. A contemplated future version of the system would include a microprocessor-based control subsystem that would include cord

  19. Brief Communication: Upper-air relaxation in RACMO2 significantly improves modelled interannual surface mass balance variability in Antarctica

    NASA Astrophysics Data System (ADS)

    van de Berg, Willem Jan; Medley, Brooke

    2016-03-01

    The Regional Atmospheric Climate Model (RACMO2) has been a powerful tool for improving surface mass balance (SMB) estimates from GCMs or reanalyses. However, new yearly SMB observations for West Antarctica show that the modelled interannual variability in SMB is poorly simulated by RACMO2, in contrast to ERA-Interim, which resolves this variability well. In an attempt to remedy RACMO2 performance, we included additional upper-air relaxation (UAR) in RACMO2. With UAR, the correlation to observations is similar for RACMO2 and ERA-Interim. The spatial SMB patterns and ice-sheet-integrated SMB modelled using UAR remain very similar to the estimates of RACMO2 without UAR. We only observe an upstream smoothing of precipitation in regions with very steep topography like the Antarctic Peninsula. We conclude that UAR is a useful improvement for regional climate model simulations, although results in regions with steep topography should be treated with care.

  20. Demonstration of a Variable Phase Turbine Power System for Low Temperature Geothermal Resources

    SciTech Connect

    Hays, Lance G

    2014-07-07

    A variable phase turbine assembly will be designed and manufactured having a turbine, operable with transcritical, two-phase or vapor flow, and a generator – on the same shaft supported by process lubricated bearings. The assembly will be hermetically sealed and the generator cooled by the refrigerant. A compact plate-fin heat exchanger or tube and shell heat exchanger will be used to transfer heat from the geothermal fluid to the refrigerant. The demonstration turbine will be operated separately with two-phase flow and with vapor flow to demonstrate performance and applicability to the entire range of low temperature geothermal resources. The vapor leaving the turbine is condensed in a plate-fin refrigerant condenser. The heat exchanger, variable phase turbine assembly and condenser are all mounted on single skids to enable factory assembly and checkout and minimize installation costs. The system will be demonstrated using low temperature (237F) well flow from an existing large geothermal field. The net power generated, 1 megawatt, will be fed into the existing power system at the demonstration site. The system will demonstrate reliable generation of inexpensive power from low temperature resources. The system will be designed for mass manufacturing and factory assembly and should cost less than $1,200/kWe installed, when manufactured in large quantities. The estimated cost of power for 300F resources is predicted to be less than 5 cents/kWh. This should enable a substantial increase in power generated from low temperature geothermal resources.

  1. A MacCormack-TVD finite difference method to simulate the mass flow in mountainous terrain with variable computational domain

    NASA Astrophysics Data System (ADS)

    Ouyang, Chaojun; He, Siming; Xu, Qiang; Luo, Yu; Zhang, Wencheng

    2013-03-01

    A two-dimensional mountainous mass flow dynamic procedure solver (Massflow-2D) using the MacCormack-TVD finite difference scheme is proposed. The solver is implemented in Matlab on structured meshes with variable computational domain. To verify the model, a variety of numerical test scenarios, namely, the classical one-dimensional and two-dimensional dam break, the landslide in Hong Kong in 1993 and the Nora debris flow in the Italian Alps in 2000, are executed, and the model outputs are compared with published results. It is established that the model predictions agree well with both the analytical solution as well as the field observations.

  2. Orbital parameters and variability of the emission spectrum for the massive binary system 103 Tau

    NASA Astrophysics Data System (ADS)

    Tarasov, A. E.

    2016-09-01

    Based on high-resolution spectra taken near the He I 6678 Å line for the massive binary system 103 Tau, we have detected a weak absorption component belonging to the binary's secondary component. We have measured the radial velocities of both components, improved the previously known orbital parameters, and determined the new ones. The binary has an orbital period P orb = 58.305d, an orbital eccentricity e = 0.277, a radial velocity semi-amplitude of the bright component K A = 44.8 km s-1, and a component mass ratio M A / M B = 1.77. The absence of photometric variability and the estimates of physical parameters for the primary component suggest that the binary most likely has a considerable inclination of the orbital plane to the observer, i ≈ 50°-60°. In this case, the secondary component is probably a normal dwarf of spectral type B5-B8. Based on the spectra taken near the H α line, we have studied the variability of the emission profile. It is shown to be formed in the Roche lobe of the secondary component, but no traces of active mass exchange in the binary have been detected.

  3. High-performance mass storage system for workstations

    NASA Technical Reports Server (NTRS)

    Chiang, T.; Tang, Y.; Gupta, L.; Cooperman, S.

    1993-01-01

    Reduced Instruction Set Computer (RISC) workstations and Personnel Computers (PC) are very popular tools for office automation, command and control, scientific analysis, database management, and many other applications. However, when using Input/Output (I/O) intensive applications, the RISC workstations and PC's are often overburdened with the tasks of collecting, staging, storing, and distributing data. Also, by using standard high-performance peripherals and storage devices, the I/O function can still be a common bottleneck process. Therefore, the high-performance mass storage system, developed by Loral AeroSys' Independent Research and Development (IR&D) engineers, can offload a RISC workstation of I/O related functions and provide high-performance I/O functions and external interfaces. The high-performance mass storage system has the capabilities to ingest high-speed real-time data, perform signal or image processing, and stage, archive, and distribute the data. This mass storage system uses a hierarchical storage structure, thus reducing the total data storage cost, while maintaining high-I/O performance. The high-performance mass storage system is a network of low-cost parallel processors and storage devices. The nodes in the network have special I/O functions such as: SCSI controller, Ethernet controller, gateway controller, RS232 controller, IEEE488 controller, and digital/analog converter. The nodes are interconnected through high-speed direct memory access links to form a network. The topology of the network is easily reconfigurable to maximize system throughput for various applications. This high-performance mass storage system takes advantage of a 'busless' architecture for maximum expandability. The mass storage system consists of magnetic disks, a WORM optical disk jukebox, and an 8mm helical scan tape to form a hierarchical storage structure. Commonly used files are kept in the magnetic disk for fast retrieval. The optical disks are used as archive

  4. Multiple-Point Mass Flux Measurement System Using Rayleigh Scattering

    NASA Technical Reports Server (NTRS)

    Mielke, Amy F.; Elam, Kristie A.; Clem, Michelle M.

    2009-01-01

    A multiple-point Rayleigh scattering diagnostic is being developed to provide mass flux measurements in gas flows. Spectroscopic Rayleigh scattering is an established flow diagnostic that has the ability to provide simultaneous density, temperature, and velocity measurements. Rayleigh scattered light from a focused 18 Watt continuous-wave laser beam is directly imaged through a solid Fabry-Perot etalon onto a CCD detector which permits spectral analysis of the light. The spatial resolution of the measurements is governed by the locations of interference fringes, which can be changed by altering the etalon characteristics. A prototype system has been used to acquire data in a Mach 0.56 flow to demonstrate feasibility of using this system to provide mass flux measurements. Estimates of measurement uncertainty and recommendations for system improvements are presented

  5. Determination of the System Mass and the Individual Masses of the Pluto System from New Horizons Radio Tracking

    NASA Astrophysics Data System (ADS)

    Hahn, Matthias; Pätzold, Martin; Andert, Tom; Bird, Michael K.; Tyler, Leonard G.; Linscott, Ivan; Hinson, Dave P.; Stern, Alan; Weaver, Hal; Olkin, Cathrin; Young, Leslie; Ennico, Kimberly

    2015-11-01

    One objective of the New Horizons Radio Science Experiment REX is the determination of the system mass and the individual masses of Pluto and Charon. About four weeks of two-way radio tracking centered around the closest approach of New Horizons to the Pluto system were processed. Major problems during the processing were caused by the small net forces of the spacecraft thruster activity, which produce extra Δv on the spacecraft motion superposed onto the continuously perturbed motion caused by the attracting forces of the Pluto system. The times of spacecraft thruster activity are known but the applied Δv needs to be specifically adjusted. No two-way tracking was available for the day of the flyby, but slots of REX one-way uplink tracking are used to cover the most important times near closest approach, e.g. during occultation entries and exits. This will help to separate the individual masses of Pluto and Charon from the system mass.

  6. 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.

  7. 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.

  8. 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.

  9. Screening of Electric field in a Variable Range Hopping System

    NASA Astrophysics Data System (ADS)

    Prigodin, Vladimir; Epstein, Arthur

    2003-03-01

    Recent report of a field effect in conducting polymers [1] initiated a large interest. The "field effect" can not be explained only by electrochemical dedoping of polymers. Also the field effect is impossible to understand within a model of homogeneous conductor because of the atomic scale of Debye radius. We discuss the penetration of electric field in a system in which charge transport is provided by variable range hopping (VRH). The majority of carriers are localized and contribute to the dielectric constant. An exponentially small fraction of carriers are mobile and screens the external field. Our estimate shows that the screening length for conducting polymers can be essentially larger than in metals but is still not enough to explain the experimental data. A combination of different factors including the inhomogeneous (granular) structure of conducting polymers may control the observable phenomena. J. Lu et al., J. Appl. Phys. XX, in press (2002); A.J. Epstein et al., Current Appl. Lett. 2, 339 (2002); M. Ishihara and H. Okuzaki, Synth. Met. XX, in press (2003).

  10. 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

  11. An Infinite Order Discrete Variable Representation of an Effective Mass Hamiltonian: Application to Exciton Wave Functions in Quantum Confined Nanostructures.

    PubMed

    Kaledin, Alexey L; Lian, Tianquan; Hill, Craig L; Musaev, Djamaladdin G

    2014-08-12

    We describe an extension of the conventional Fourier grid discrete variable representation (DVR) to the bound state problem of a particle with a position-dependent mass. An infinite order DVR, derived for a variable mass kinetic energy operator, coupled with an efficient grid contraction scheme yields essentially exact eigenvalues for a chosen grid spacing. Implementation of the method is shown to be very practical due to the fact that in a DVR no integral evaluation is necessary and that the resultant kinetic energy matrix is sparse. Numerical calculations are presented for exciton states of spherical, cylindrical, and toric Type I (CdSe/ZnS) core-shell quantum dots. In these examples, electron-hole interaction is treated explicitly by solving a self-consistent Schrödinger-Poisson equation on a contracted DVR grid. Prospective applications of the developed approach to calculating electron transfer rates between adsorbed molecular acceptors and quantum confined nanocrystals of generic shape, dimensionality, and composition are also discussed.

  12. Annual variation of coastal uplift in Greenland as an indicator of variable and accelerating ice mass loss

    NASA Astrophysics Data System (ADS)

    Yang, Qian; Wdowinski, Shimon; Dixon, Timothy H.

    2013-05-01

    Seasonal melting of the coastal part of the Greenland ice sheet is investigated using GPS vertical displacement data from coastal stations, combined with data on atmospheric and ocean temperatures. Using a high pass filter and cubic spline models, we estimate five variables describing seasonal uplift, a proxy for proximal mass loss, including duration of the melt season and the amount of summer uplift. Our analysis shows both temporal and spatial variations of uplift. Southern coastal Greenland experienced anomalously large uplift in summer 2010, implying significant melting that year. However, the northwest coast did not experience significant change in uplift at that time. Our data suggest that a combination of warm summer air temperature and warm sub-surface ocean water temperature drove the large mass losses in 2010. Using the uplift pattern of 2008-2010, and comparing to atmospheric data and ocean water temperature data, we show that warm Irminger Water (IW) exerted significant influence on coastal melting in southeastern, southern and southwestern Greenland, reaching about 69°N in 2010. North of this, IW did not exert significant influence, in effect defining the northward limit of the sub-polar gyre for that year. Thus, short-term variability in the coastal GPS uplift signal can be used to infer an oceanographic parameter that has a critical influence on Greenland ice sheet health.

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

    SciTech Connect

    Dragomir, Diana; Matthews, Jaymie M.; Kane, Stephen R.; Ciardi, David R.; Von Braun, Kaspar; Henry, Gregory W.; Fischer, Debra A.; Howard, Andrew W.; Jensen, Eric L. N.; Laughlin, Gregory

    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} .

  14. Variability in atmospheric particulates and meteorological effects on their mass concentrations over Delhi, India

    NASA Astrophysics Data System (ADS)

    Tiwari, S.; Bisht, D. S.; Srivastava, A. K.; Pipal, A. S.; Taneja, A.; Srivastava, M. K.; Attri, S. D.

    2014-08-01

    Simultaneous and continuous measurements of PM2.5 and PM10 along with other co-existent pollutants viz., black carbon (BC), CO, NO and NOx were carried out over Delhi with high resolution (5 min) datasets from 1st Sept. 2010 to 23rd Aug. 2012. Arithmetic mean mass concentrations of PM2.5 and PM10 were about 130 ± 103 and 222 ± 142 μg m- 3 respectively during the entire measurement period, which are considerably higher than the annual averages of PM2.5 and PM10, stipulated by the National and International standards. It was noticed that the fine mode particles (PM2.5) were higher than the coarse mode particles (PM10-2.5) during post-monsoon (~ 89%), winter (~ 69%) and monsoon (~ 64%) periods; however, PM10-2.5 was higher (~ 22%) than PM2.5 during summer. Arithmetic mean mass concentrations of BC, CO, NO and NOx were about 7 ± 5 μg m- 3, 2 ± 1 ppm, 17 ± 17 ppb and 30 ± 24 ppb, respectively. In the present study, highest fraction of BC (~ 6%) in PM2.5 mass was in winter, whereas the lowest fraction (~ 4%) was in summer. Relationships among PMs (particulate matters) and other pollutants indicated that the fine mode particles are highly correlated with BC (0.74) and CO (0.51). The effects of meteorological parameters on aerosols have been studied and a significant negative relationship (- 0.45) between mixing height (MH) and PM2.5 has been noticed. Higher correlation was during winter (- 0.55), however lower was in summer (- 0.16). Relation between visibility (VIS) and PM2.5 was higher during post-monsoon (- 0.85) and winter (- 0.78) when the visibility was around 2 km; however, it was relatively less correlated when VIS was greater than 2 km during summer and monsoon. Relationship between PM2.5 and relative humidity (RH) showed a significant negative correlation (- 0.56) for the entire study period. A positive correlation (0.32) was observed during the winter period with fine mode particles whereas negative correlation was seen with coarse mode particles during

  15. Luminous blue variables are antisocial: their isolation implies that they are kicked mass gainers in binary evolution

    NASA Astrophysics Data System (ADS)

    Smith, Nathan; Tombleson, Ryan

    2015-02-01

    Based on their relatively isolated environments, we argue that luminous blue variables (LBVs) must be primarily the product of binary evolution, challenging the traditional single-star view wherein LBVs mark a brief transition between massive O-type stars and Wolf-Rayet (WR) stars. If the latter were true, then LBVs should be concentrated in young massive clusters like early O-type stars. This is decidedly not the case. Examining locations of LBVs in our Galaxy and the Magellanic Clouds reveals that, with only a few exceptions, LBVs systematically avoid clusters of O-type stars. In the Large Magellanic Cloud, LBVs are statistically much more isolated than O-type stars, and (perhaps most surprisingly) even more isolated than WR stars. This makes it impossible for LBVs to be single `massive stars in transition' to WR stars. Instead, we propose that massive stars and supernova (SN) subtypes are dominated by bifurcated evolutionary paths in interacting binaries, wherein most WR stars and Type Ibc supernovae (SNe Ibc) correspond to the mass donors, while LBVs (and their lower mass analogues like B[e] supergiants, which are even more isolated) are the mass gainers. In this view, LBVs are evolved massive blue stragglers. Through binary mass transfer, rejuvinated mass gainers get enriched, spun up, and sometimes kicked far from their clustered birth sites by their companion's SN. This scenario agrees better with LBVs exploding as SNe IIn in isolation, and it predicts that many massive runaway stars may be rapid rotators. Mergers or blue Thorne-Zytkow-like objects might also give rise to LBVs, but these scenarios may have a harder time explaining why LBVs avoid clusters.

  16. Quality management in clinical application of mass spectrometry measurement systems.

    PubMed

    Vogeser, Michael; Seger, Christoph

    2016-09-01

    Thanks to highly specific analyte detection and potentially complete compensation for matrix variables based on the principle of stable isotope derivative internal standardisation, mass spectrometry methods allow the development of diagnostic tests of outstanding analytical quality. However, these features per se do not guarantee reliability of tests. A wide range of factors can introduce analytical errors and inaccuracy due to the extreme complexity of the methods involved. Furthermore, it can be expected that the application patterns of MS methods in diagnostic laboratories will change substantially during the coming years - with presumably less specialised laboratories implementing mass spectrometry. Introduction of highly automated test solutions by manufacturers will require some trade-off between operation convenience, sample throughput and analytical performance. Structured and careful quality and risk management is therefore crucial to translate the analytical power of mass spectrometry into actionable and reliable results for individual patients' care and to maintain the degree of reliability that is expected from MS methods in clinical pathology. This reflection review discusses whether particular quality assurance tools have to be applied for MS-based diagnostic tests and whether these tools are different from those applied for optical- and affinity-based standard tests. Both pre-implementation strategies and surveillance of assays with assessment of metadata in routine testing are addressed. The release of the CLSI guideline C62-A in 2014 was a substantial achievement in this context because it addresses a wide spectrum of relevant issues in quality assurance of mass spectrometry-based clinical tests. However, the translation of this best practice document into individual laboratory settings is likely to be heterogeneous.

  17. Stability of uncertain impulsive complex-variable chaotic systems with time-varying delays.

    PubMed

    Zheng, Song

    2015-09-01

    In this paper, the robust exponential stabilization of uncertain impulsive complex-variable chaotic delayed systems is considered with parameters perturbation and delayed impulses. It is assumed that the considered complex-variable chaotic systems have bounded parametric uncertainties together with the state variables on the impulses related to the time-varying delays. Based on the theories of adaptive control and impulsive control, some less conservative and easily verified stability criteria are established for a class of complex-variable chaotic delayed systems with delayed impulses. Some numerical simulations are given to validate the effectiveness of the proposed criteria of impulsive stabilization for uncertain complex-variable chaotic delayed systems.

  18. Saponification reaction system: a detailed mass transfer coefficient determination.

    PubMed

    Pečar, Darja; Goršek, Andreja

    2015-01-01

    The saponification of an aromatic ester with an aqueous sodium hydroxide was studied within a heterogeneous reaction medium in order to determine the overall kinetics of the selected system. The extended thermo-kinetic model was developed compared to the previously used simple one. The reaction rate within a heterogeneous liquid-liquid system incorporates a chemical kinetics term as well as mass transfer between both phases. Chemical rate constant was obtained from experiments within a homogeneous medium, whilst the mass-transfer coefficient was determined separately. The measured thermal profiles were then the bases for determining the overall reaction-rate. This study presents the development of an extended kinetic model for considering mass transfer regarding the saponification of ethyl benzoate with sodium hydroxide within a heterogeneous reaction medium. The time-dependences are presented for the mass transfer coefficient and the interfacial areas at different heterogeneous stages and temperatures. The results indicated an important role of reliable kinetic model, as significant difference in k(L)a product was obtained with extended and simple approach.

  19. Simplified Simulation of Mass Transfer in Double White Dwarf Systems

    NASA Astrophysics Data System (ADS)

    Vannah, Sara; Frank, Juhan

    2016-01-01

    The behavior both stable and unstable mass transfer in semi-detached double white dwarfs triggers a cornucopia of astrophysical phenomena including Type Ia supernovae and AM CVn stars. Current 3D hydrodynamic simulations of the evolution these systems following the mass transfer, binary orbital parameters, and the self-consistent gravitational field over several tens of orbital periods have produced a wealth of data. However, these simulations can take weeks to months in high-performance computing platforms to execute. To help with the interpretation of results of such large scale simulations, and to enable a quick exploration of binary parameter space, we have developed a Mathematica code that integrates forward in time a system of 5 ODEs describing the orbit-averaged evolution of the binary separation as well as the radius, mass, and spin angular momentum of both components of the binary. By adjusting a few parameters describing the mass transfer as a function of the Roche-lobe overflow and the strength of the tidal coupling between the orbit and component spins we are able to obtain approximate fits to previously run hydrodynamic simulations. This simplified simulation is able to run simulations similar to the hydrodynamic versions in a matter of seconds on a dual-core PC or Mac computer.

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

    SciTech Connect

    Hong, Tainzhen; Liu, Xaiobing

    2009-11-01

    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 preliminary comparison of energy efficiency between the air-source VRF and GSHP systems is presented. The computer simulation results show that GSHP system is more energy efficient than the air-source VRF system for conditioning a small office building in two selected US climates. In general, GSHP system is more energy efficient than the air-source VRV system, especially when the building has significant heating loads. For buildings with less heating loads, the GSHP system could still perform better than the air-source VRF system in terms of energy efficiency, but the resulting energy savings may be marginal.

  1. 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

  2. Anthropogenic impact on Antarctic surface mass balance, currently masked by natural variability, to emerge by mid-century

    NASA Astrophysics Data System (ADS)

    Previdi, Michael; Polvani, Lorenzo M.

    2016-09-01

    Global and regional climate models robustly simulate increases in Antarctic surface mass balance (SMB) during the twentieth and twenty-first centuries in response to anthropogenic global warming. Despite these robust model projections, however, observations indicate that there has been no significant change in Antarctic SMB in recent decades. We show that this apparent discrepancy between models and observations can be explained by the fact that the anthropogenic climate change signal during the second half of the twentieth century is small compared to the noise associated with natural climate variability. Using an ensemble of 35 global coupled climate models to separate signal and noise, we find that the forced SMB increase due to global warming in recent decades is unlikely to be detectable as a result of large natural SMB variability. However, our analysis reveals that the anthropogenic impact on Antarctic SMB is very likely to emerge from natural variability by the middle of the current century, thus mitigating future increases in global sea level.

  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

  4. A system of three-dimensional complex variables

    NASA Technical Reports Server (NTRS)

    Martin, E. Dale

    1986-01-01

    Some results of a new theory of multidimensional complex variables are reported, including analytic functions of a three-dimensional (3-D) complex variable. Three-dimensional complex numbers are defined, including vector properties and rules of multiplication. The necessary conditions for a function of a 3-D variable to be analytic are given and shown to be analogous to the 2-D Cauchy-Riemann equations. A simple example also demonstrates the analogy between the newly defined 3-D complex velocity and 3-D complex potential and the corresponding ordinary complex velocity and complex potential in two dimensions.

  5. 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.

  6. Grand challenges in mass storage: A system integrator's perspective

    NASA Technical Reports Server (NTRS)

    Mintz, Dan; Lee, Richard

    1993-01-01

    The grand challenges are the following: to develop more innovation in approach; to expand the I/O barrier; to achieve increased volumetric efficiency and incremental cost improvements; to reinforce the 'weakest link' software; to implement improved architectures; and to minimize the impact of self-destructing technologies. Mass storage is defined as any type of storage system exceeding 100 GBytes in total size, under the control of a centralized file management scheme. The topics covered are presented in viewgraph form.

  7. Recent Variability Observations of Solar System Giant Planets: Fresh Context for Understanding Exoplanet and Brown Dwarf Weather

    NASA Astrophysics Data System (ADS)

    Marley, Mark S.; Kepler Giant Planet Variability Team, Spitzer Ice Giant Variability Team

    2016-10-01

    Over the past several years a number of of high cadence photometric observations of solar system giant planets have been acquired by various platforms. Such observations are of interest as they provide points of comparison to the already expansive set of brown dwarf variability observations and the small, but growing, set of exoplanet variability observations. By measuring how rapidly the integrated light from solar system giant planets can evolve, variability observations of substellar objects that are unlikely to ever be resolved can be placed in a fuller context. Examples of brown dwarf variability observations include extensive work from the ground (e.g., Radigan et al. 2014), Spitzer (e.g., Metchev et al. 2015), Kepler (Gizis et al. 2015), and HST (Yang et al. 2015). Variability has been measured on the planetary mass companion to the brown dwarf 2MASS 1207b (Zhou et al. 2016) and further searches are planned in thermal emission for the known directly imaged planets with ground based telescopes (Apai et al. 2016) and in reflected light with future space based telescopes. Recent solar system variability observations include Kepler monitoring of Neptune (Simon et al. 2016) and Uranus, Spitzer observations of Neptune (Stauffer et al. 2016), and Cassini observations of Jupiter (West et al. in prep). The Cassini observations are of particular interest as they measured the variability of Jupiter at a phase angle of ˜60○, comparable to the viewing geometry expected for space based direct imaging of cool extrasolar Jupiters in reflected light. These solar system analog observations capture many of the characteristics seen in brown dwarf variability, including large amplitudes and rapid light curve evolution on timescales as short as a few rotation periods. Simon et al. (2016) attribute such variations at Neptune to a combination of large scale, stable cloud structures along with smaller, more rapidly varying, cloud patches. The observed brown dwarf and exoplanet

  8. Recent Variability Observations of Solar System Giant Planets: Fresh Context for Understanding Exoplanet and Brown Dwarf Weather

    NASA Technical Reports Server (NTRS)

    Marley, Mark Scott

    2016-01-01

    Over the past several years a number of high cadence photometric observations of solar system giant planets have been acquired by various platforms. Such observations are of interest as they provide points of comparison to the already expansive set of brown dwarf variability observations and the small, but growing, set of exoplanet variability observations. By measuring how rapidly the integrated light from solar system giant planets can evolve, variability observations of substellar objects that are unlikely to ever be resolved can be placed in a fuller context. Examples of brown dwarf variability observations include extensive work from the ground (e.g., Radigen et al. 2014), Spitzer (e.g., Metchev et al. 2015), Kepler (Gizis et al. 2015), and HST (Yang et al. 2015).Variability has been measured on the planetary mass companion to the brown dwarf 2MASS 1207b (Zhou et al. 2016) and further searches are planned in thermal emission for the known directly imaged planets with ground based telescopes (Apai et al. 2016) and in reflected light with future space based telescopes. Recent solar system variability observations include Kepler monitoring of Neptune (Simon et al. 2016) and Uranus, Spitzer observations of Neptune (Stauffer et al. 2016), and Cassini observations of Jupiter (West et al. in prep). The Cassini observations are of particular interest as they measured the variability of Jupiter at a phase angle of approximately 60 deg, comparable to the viewing geometry expected for space based direct imaging of cool extrasolar Jupiters in reflected light. These solar system analog observations capture many of the characteristics seen in brown dwarf variability, including large amplitudes and rapid light curve evolution on timescales as short as a few rotation periods. Simon et al. (2016) attribute such variations at Neptune to a combination of large scale, stable cloud structures along with smaller, more rapidly varying, cloud patches. The observed brown dwarf and

  9. 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

  10. Mass transfer in binary X-ray systems

    NASA Technical Reports Server (NTRS)

    Mccray, R.; Hatchett, S.

    1975-01-01

    The influence of X-ray heating on gas flows in binary X-ray systems is examined. A simple estimate is obtained for the evaporative wind flux from a stellar atmosphere due to X-ray heating which agrees with numerical calculations by Alme and Wilson (1974) but disagrees with calculations by Arons (1973) and by Basko and Sunyaev (1974) for the Her X-1/HZ Her system. The wind flux is sensitive to the soft X-ray spectrum. The self-excited wind mechanism does not work. Mass transfer in the Hercules system probably occurs by flow of the atmosphere of HZ Her through the gravitational saddle point of the system. The accretion gas stream is probably opaque with atomic density of not less than 10 to the 15th power per cu cm and is confined to a small fraction of 4(pi) steradians. Other binary X-ray systems are briefly discussed.

  11. 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.

  12. Mass-Flow-Meter Leak-Testing System

    NASA Technical Reports Server (NTRS)

    Sorensen, Eric B.; Polidori, Andre V.; Heman, Joe R.; Dresser, Holland L.; Hellum, John

    1996-01-01

    Improved leak-testing system incorporates mass-flow meter as primary sensor for measurement of leakage rate. System easier to use and more reliable and enables leak tests to be completed in less time. Produces test data more plentiful, more accurate, and better suited to leak detection and diagnosis. Operates over range of test conditions, including pressures from atmospheric to 1,000 psi, temperatures from 50 to 120 degrees F and volumes from less than 1 in.(sup3) to 22 in.(sup3). Sensitive enough to measure absorbed gas seeping from O-ring seals after test pressure released.

  13. 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.

  14. The mass, energy, space and time systemic theory-MEST

    NASA Astrophysics Data System (ADS)

    Cao, Dayong

    2011-11-01

    The displacement and period of the orbit of the motion are the space-time; the probability of them are the quantum space-time. Both of the energy-momentum tensor and metric tensor belong to the gravitational field. It can direct the space-time. The black hole has a space-time center as a origin of a mass-energy coordinate system and a binding energy of space-time like that sun has a mass-energy center and the nuclear energy. And it has a dark matter field around. There is a balance energy equation between sun and black hole. E = hν = mc2 Among it, E: the energy of wave of sun, m: the mass of wave, c: the velocity of wave, ν: the frequence of wave, h: the Planck constant. E' ψ = iℏ∂ψ/∂t m' ψ = - iℏ∂ψ∂t/(∂ x) 2 Among it, E' ψ : the energy of dark wave of black hole, m' ψ : the mass of dark wave, c': the velocity of dark wave, ψ: the Wave Functions. hν +E' ψ = mc2 +m' ψc'2 , (c'2 = -(∂x)/2 (∂t) 2)

  15. 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.

  16. The linear system theory's account of behavior maintained by variable-ratio schedules.

    PubMed

    McDowell, J J; Wixted, J T

    1988-01-01

    The mathematical theory of linear systems, which has been used successfully to describe behavior maintained by variable-interval schedules, is extended to describe behavior maintained by variable-ratio schedules. The result of the analysis is a pair of equations, one of which expresses response rate on a variable-ratio schedule as a function of the mean ratio requirement (n) that the schedule arranges. The other equation expresses response rate on a variable-ratio schedule as a function of reinforcement rate. Both equations accurately describe existing data from variable-ratio schedules. The theory accounts for two additional characteristics of behavior maintained by variable-ratio schedules; namely, the appearance of strained, two-valued (i.e., zero or very rapid) responding at large ns, and the abrupt cessation of responding at a boundary n. The theory also accounts for differences between behavior on variable-interval and variable-ratio schedules, including (a) the occurrence of strained responding on variable-ratio but not on variable-interval schedules, (b) the abrupt cessation of responding on occurrence of higher response rates on variable-ratio than on variable-interval schedules. Furthermore, given data from a series of variable-interval schedules and from a series of concurrent variable-ratio variable-interval schedules, the theory permits quantitative prediction of many properties of behavior on single-alternative variable-ratio schedules. The linear system theory's combined account of behavior on variable-interval and variable-ratio schedules is superior to existing versions of six other mathematical theories of variable-interval and variable-ratio responding.

  17. The linear system theory's account of behavior maintained by variable-ratio schedules.

    PubMed Central

    McDowell, J J; Wixted, J T

    1988-01-01

    The mathematical theory of linear systems, which has been used successfully to describe behavior maintained by variable-interval schedules, is extended to describe behavior maintained by variable-ratio schedules. The result of the analysis is a pair of equations, one of which expresses response rate on a variable-ratio schedule as a function of the mean ratio requirement (n) that the schedule arranges. The other equation expresses response rate on a variable-ratio schedule as a function of reinforcement rate. Both equations accurately describe existing data from variable-ratio schedules. The theory accounts for two additional characteristics of behavior maintained by variable-ratio schedules; namely, the appearance of strained, two-valued (i.e., zero or very rapid) responding at large ns, and the abrupt cessation of responding at a boundary n. The theory also accounts for differences between behavior on variable-interval and variable-ratio schedules, including (a) the occurrence of strained responding on variable-ratio but not on variable-interval schedules, (b) the abrupt cessation of responding on occurrence of higher response rates on variable-ratio than on variable-interval schedules. Furthermore, given data from a series of variable-interval schedules and from a series of concurrent variable-ratio variable-interval schedules, the theory permits quantitative prediction of many properties of behavior on single-alternative variable-ratio schedules. The linear system theory's combined account of behavior on variable-interval and variable-ratio schedules is superior to existing versions of six other mathematical theories of variable-interval and variable-ratio responding. PMID:3279150

  18. 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.

  19. 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

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

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 23 Highways 1 2013-04-01 2013-04-01 false Approval of urban system nonhighway public mass transit... PUBLIC TRANSPORTATION MASS TRANSIT AND SPECIAL USE HIGHWAY PROJECTS Federal-Aid Urban System Nonhighway Public Mass Transit Projects § 810.308 Approval of urban system nonhighway public mass transit...

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

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 23 Highways 1 2014-04-01 2014-04-01 false Approval of urban system nonhighway public mass transit... PUBLIC TRANSPORTATION MASS TRANSIT AND SPECIAL USE HIGHWAY PROJECTS Federal-Aid Urban System Nonhighway Public Mass Transit Projects § 810.308 Approval of urban system nonhighway public mass transit...

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

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 23 Highways 1 2011-04-01 2011-04-01 false Approval of urban system nonhighway public mass transit... PUBLIC TRANSPORTATION MASS TRANSIT AND SPECIAL USE HIGHWAY PROJECTS Federal-Aid Urban System Nonhighway Public Mass Transit Projects § 810.308 Approval of urban system nonhighway public mass transit...

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

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Approval of urban system nonhighway public mass transit... PUBLIC TRANSPORTATION MASS TRANSIT AND SPECIAL USE HIGHWAY PROJECTS Federal-Aid Urban System Nonhighway Public Mass Transit Projects § 810.308 Approval of urban system nonhighway public mass transit...

  4. The NEEDS Data Base Management and Archival Mass Memory System

    NASA Technical Reports Server (NTRS)

    Bailey, G. A.; Bryant, S. B.; Thomas, D. T.; Wagnon, F. W.

    1980-01-01

    A Data Base Management System and an Archival Mass Memory System are being developed that will have a 10 to the 12th bit on-line and a 10 to the 13th off-line storage capacity. The integrated system will accept packetized data from the data staging area at 50 Mbps, create a comprehensive directory, provide for file management, record the data, perform error detection and correction, accept user requests, retrieve the requested data files and provide the data to multiple users at a combined rate of 50 Mbps. Stored and replicated data files will have a bit error rate of less than 10 to the -9th even after ten years of storage. The integrated system will be demonstrated to prove the technology late in 1981.

  5. System Modeling of Lunar Oxygen Production: Mass and Power Requirements

    NASA Technical Reports Server (NTRS)

    Steffen, Christopher J.; Freeh, Joshua E.; Linne, Diane L.; Faykus, Eric W.; Gallo, Christopher A.; Green, Robert D.

    2007-01-01

    A systems analysis tool for estimating the mass and power requirements for a lunar oxygen production facility is introduced. The individual modeling components involve the chemical processing and cryogenic storage subsystems needed to process a beneficiated regolith stream into liquid oxygen via ilmenite reduction. The power can be supplied from one of six different fission reactor-converter systems. A baseline system analysis, capable of producing 15 metric tons of oxygen per annum, is presented. The influence of reactor-converter choice was seen to have a small but measurable impact on the system configuration and performance. Finally, the mission concept of operations can have a substantial impact upon individual component size and power requirements.

  6. Simulating variably-saturated reactive transport of selenium and nitrogen in agricultural groundwater systems

    NASA Astrophysics Data System (ADS)

    Bailey, Ryan T.; Gates, Timothy K.; Halvorson, Ardell D.

    2013-06-01

    Selenium (Se) contamination in environmental systems has become a major issue in many regions world-wide during the previous decades, with both elevated and deficient Se concentrations in groundwater, surface water, soils and associated cultivated crops reported. To provide a tool that can assess baseline conditions and explore remediation strategies, this paper presents a numerical model capable of simulating the reactive transport of Se species in large-scale variably-saturated groundwater systems influenced by agricultural practices. Developed by incorporating a Se reaction module into the multi-species, variably-saturated reactive transport model UZF-RT3D, model features include near-surface Se cycling due to agricultural practices, oxidation-reduction reactions, and the inclusion of a nitrogen (N) cycle and reaction module due to the dependence of Se transformation and speciation on the presence of nitrate (NO3). Although the primary motivation is applying the model to large-scale systems, this paper presents applications to agricultural soil profile systems to corroborate the near-surface module processes that are vital in estimating mass loadings to the saturated zone in large-scale fate and transport studies. The first application jointly tests the Se and N modules for corn test plots receiving varying loadings of fertilizer, whereas the second application tests the N module for fertilized and unfertilized test plots. Results indicate that the model is successful in reproducing observed measurements of Se and NO3 concentrations, particularly in lower soil layers and hence in regards to leaching. For the first application, the Ensemble Kalman Filter (EnKF) is used to condition model parameters, demonstrating the usefulness of the EnKF in real-world reactive transport systems.

  7. Simulating variably-saturated reactive transport of selenium and nitrogen in agricultural groundwater systems.

    PubMed

    Bailey, Ryan T; Gates, Timothy K; Halvorson, Ardell D

    2013-06-01

    Selenium (Se) contamination in environmental systems has become a major issue in many regions world-wide during the previous decades, with both elevated and deficient Se concentrations in groundwater, surface water, soils and associated cultivated crops reported. To provide a tool that can assess baseline conditions and explore remediation strategies, this paper presents a numerical model capable of simulating the reactive transport of Se species in large-scale variably-saturated groundwater systems influenced by agricultural practices. Developed by incorporating a Se reaction module into the multi-species, variably-saturated reactive transport model UZF-RT3D, model features include near-surface Se cycling due to agricultural practices, oxidation-reduction reactions, and the inclusion of a nitrogen (N) cycle and reaction module due to the dependence of Se transformation and speciation on the presence of nitrate (NO₃). Although the primary motivation is applying the model to large-scale systems, this paper presents applications to agricultural soil profile systems to corroborate the near-surface module processes that are vital in estimating mass loadings to the saturated zone in large-scale fate and transport studies. The first application jointly tests the Se and N modules for corn test plots receiving varying loadings of fertilizer, whereas the second application tests the N module for fertilized and unfertilized test plots. Results indicate that the model is successful in reproducing observed measurements of Se and NO₃ concentrations, particularly in lower soil layers and hence in regards to leaching. For the first application, the Ensemble Kalman Filter (EnKF) is used to condition model parameters, demonstrating the usefulness of the EnKF in real-world reactive transport systems.

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

    PubMed

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

    2006-05-18

    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.

  9. 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.

  10. Systematics of Rotational Bands in Odd-Mass Nuclei on the Basis of the Variable Moment of Inertia Model

    SciTech Connect

    Mitropolsky, I.

    2005-05-24

    On the grounds of a file of the evaluated nuclear data ENSDF, the most complete compilation of rotational bands in odd-A nuclei with mass numbers 43{<=}A{<=}253 is presented. The processing of experimental data has been carried out on the basis of generalization of the variable moment of inertia model for axial strong deformed nuclei, which is taking into account the decoupling effect for bands with K=1/2. The good description of rotational energies for the majority of rotational bands is obtained and the systematic behavior of the model parameters in all areas of the deformed nuclei is shown. The theoretical description was used for association of fragments of rotational bands, exclusion of 'superfluous' levels and prediction of a placement of 'missed' levels.

  11. The Infrared Variability of GX17+2 and Low-Mass X-ray Binary Jets

    NASA Astrophysics Data System (ADS)

    McNamara, Bernard J.; Bornak, J.; Harrison, T.; Rupen, M.

    2007-12-01

    GX17+2 is a low-mass X-ray binary. It is also classified as a Z-source since it exhibits a distinctive Z-pattern in its X-ray color-color plot. GX17+2 is located in the direction of the galactic center and is not detectable at optical wavelengths. Its emission varies by over 4 magnitudes in the infrared. A number of explanations have been advanced to explain this variabilty. Based upon KPNO and Smarts IR observations, we suggest that it arises from a sychrotron jet which is periodically visible along our line of sight. This circumstance provides a rather unique opportunity to quantify a number of jet properties such as its opening angle, the sharpness of the jet boundaries, its variability, and the infrared emission uniformity across the jet.

  12. Singularly perturbed control systems with noncompact fast variable

    NASA Astrophysics Data System (ADS)

    Nguyen, Thuong; Siconolfi, Antonio

    2016-10-01

    We deal with a singularly perturbed optimal control problem with slow and fast variable depending on a parameter ε. We study the asymptotics, as ε goes to 0, of the corresponding value functions, and show convergence, in the sense of weak semilimits, to sub and supersolution of a suitable limit equation containing the effective Hamiltonian. The novelty of our contribution is that no compactness condition is assumed on the fast variable. This generalization requires, in order to perform the asymptotic procedure, an accurate qualitative analysis of some auxiliary equations posed on the space of fast variable. The task is accomplished using some tools of Weak KAM theory, and in particular the notion of Aubry set.

  13. Validation and variability: dual challenges on the path from systems biology to systems medicine.

    PubMed

    Carusi, Annamaria

    2014-12-01

    Systems biology is currently making a bid to show that it is able to make an important contribution to personalised or precision medicine. In order to do so, systems biologists need to find a way of tackling the pervasive variability of biological systems that is manifested in the medical domain as inter-subject variability. This need is simultaneously social and epistemic: social as systems biologists attempt to engage with the interests and concerns of clinicians and others in applied medical research; epistemic as they attempt to develop new strategies to cope with variability in the validation of the computational models typical of systems biology. This paper describes one attempt to develop such a strategy: a trial with a population-of-models approach in the context of cardiac electrophysiology. I discuss the development of this approach against the background of ongoing tensions between mathematically and experimentally inclined modellers on the one hand, and attempts to forge new collaborations with medical scientists on the other. Apart from the scientific interest of the population-of-models approach for tackling variability, the trial also offers a good illustration of the epistemology of experiment-facing modelling. I claim that it shows the extent to which experiment-facing modelling and validation require the establishment of criteria for comparing models and experiments that enable them to be linked together. These 'grounds of comparability' are the broad framework in which validation experiments are interpreted and evaluated by all the disciplines in the collaboration, or being persuaded to participate in it. I claim that following the process of construction of the grounds of comparability allows us to see the establishment of epistemic norms for judging validation results, through a process of 'normative intra-action' (Rouse, 2002) that shape the social and epistemic evolution of systems approaches to biomedicine.

  14. Decadal variability in coupled sea-ice-thermohaline circulation systems

    SciTech Connect

    Yang, J.; Neelin, J.D.

    1997-12-01

    An interdecadal oscillation in a coupled ocean-ice system was identified in a previous study. This paper extends that study to further examine the stability of the oscillation and the sensitivity of its frequency to various parameters and forcing fields. Three models are used: (i) an analytical box model; (ii) a two-dimensional model for the ocean thermohaline circulation (THC) coupled to a thermodynamic ice model, as in the authors` previous study; and (iii) a three-dimensional ocean general circulation model (OGCM) coupled to a similar ice model. The box model is used to elucidate the essential feedbacks that give rise to this oscillation and to identify the most important parameters and processes that determine the period. The counted model becomes more stable toward low coupling, greater diffusion, and weaker THC feedback. Nonlinear effects in the sea-ice model become important in the higher ocean-ice coupling regime where the effective sea-ice damping associated with this nonlinearity stabilizes the model. The 3D OGCM is used to test this coupled ocean-ice mechanism in a more realistic model setting. This model generates an interdecadal oscillation whose characteristics and phase relations among the model variables are similar to the oscillation obtained in the 2D models. The major difference is that the oscillation frequency is considerably lower. The difference can be explained in terms of the analytical box model solution in which the period of oscillation depends on the rate of anomalous density production by melting/cooling of sea ice per SST anomaly, times the rate of warming/cooling by anomalous THC heat advection per change in density anomaly. The 3D model has a smaller THC response to high-latitude density perturbations than the 2D model, and anomalous velocities in the 3D case tend to follow the mean isotherms so anomalous heat advection is reduced. This slows the ocean-ice feedback process, leading to the longer oscillation period. 36 refs., 27 figs.

  15. Confluent hypergeometric functions and two variables Laguerre polynomials as a solutions of Wilczynski type system

    NASA Astrophysics Data System (ADS)

    Tasmambetov, Zhaxylyk

    2016-08-01

    In this work, it is considered the system of Wilczynski type, and from this system it is defined a range of systems having the solutions in the form of confluent hypergeometric functions and two variables Laguerre polynomials. It is shown that two variables confluent hypergeometric functions being the main tool of investigation of Laguerre polynomials and two variables Whittaker functions. This aspects still remaining little-investigated.

  16. Variable gearing during locomotion in the human musculoskeletal system.

    PubMed

    Carrier, D R; Heglund, N C; Earls, K D

    1994-07-29

    Human feet and toes provide a mechanism for changing the gear ratio of the ankle extensor muscles during a running step. A variable gear ratio could enhance muscle performance during constant-speed running by applying a more effective prestretch during landing, while maintaining the muscles near the high-efficiency or high-power portion of the force-velocity curve during takeoff. Furthermore, during acceleration, variable gearing may allow muscle contractile properties to remain optimized despite rapid changes in running speed. Forceplate and kinematic analyses of running steps show low gear ratios at touchdown that increase throughout the contact phase. PMID:8036513

  17. The low mass ratio contact binary system V728 Herculis

    NASA Astrophysics Data System (ADS)

    Erkan, N.; Ulaş, B.

    2016-07-01

    We present the orbital period study and the photometric analysis of the contact binary system V728 Her. Our orbital period analysis shows that the period of the system increases (dP / dt = 1.92 ×10-7 dyr-1) and the mass transfer rate from the less massive component to more massive one is 2.51 ×10-8 M⊙y-1 . In addition, an advanced sinusoidal variation in period can be attributed to the light-time effect by a tertiary component or the Applegate mechanism triggered by the secondary component. The simultaneous multicolor BVR light and radial velocity curves solution indicates that the physical parameters of the system are M1 = 1.8M⊙ , M2 = 0.28M⊙ , R1 = 1.87R⊙ , R2 = 0.82R⊙ , L1 = 5.9L⊙ , and L2 = 1.2L⊙ . We discuss the evolutionary status and conclude that V728 Her is a deep (f = 81%), low mass ratio (q = 0.16) contact binary system.

  18. 93. 22'X34' original blueprint, VariableAngle Launcher, 'OVERHEAD CAMERA SUSPENSION SYSTEM, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    93. 22'X34' original blueprint, Variable-Angle Launcher, 'OVERHEAD CAMERA SUSPENSION SYSTEM, TOWER STAY CABLES' drawn at 3/4'=1'-0'. (BUORD Sketch # 208783). - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

  19. Application of control valves and balancing valves in a variable-flow hydronic system

    SciTech Connect

    Hegberg, R.A.

    1998-10-01

    In a hydronic system design for an HVAC system with load terminals for providing heating or cooling to a building, it is desirable to provide a variable water flow under command of the space temperature/humidity control at each load terminal. This paper discusses the design of a variable-speed pumping system with proportional control.

  20. Design of a ram accelerator mass launch system

    NASA Technical Reports Server (NTRS)

    Aarnio, Michael; Armerding, Calvin; Berschauer, Andrew; Christofferson, Erik; Clement, Paul; Gohd, Robin; Neely, Bret; Reed, David; Rodriguez, Carlos; Swanstrom, Fredrick

    1988-01-01

    The ram accelerator mass launch system has been proposed to greatly reduce the costs of placing acceleration-insensitive payloads into low earth orbit. The ram accelerator is a chemically propelled, impulsive mass launch system capable of efficiently accelerating relatively large masses from velocities of 0.7 km/sec to 10 km/sec. The principles of propulsion are based on those of a conventional supersonic air-breathing ramjet; however the device operates in a somewhat different manner. The payload carrying vehicle resembles the center-body of the ramjet and accelerates through a stationary tube which acts as the outer cowling. The tube is filled with premixed gaseous fuel and oxidizer mixtures that burn in the vicinity of the vehicle's base, producing a thrust which accelerates the vehicle through the tube. This study examines the requirement for placing a 2000 kg vehicle into a 500 km circular orbit with a minimum amount of on-board rocket propellant for orbital maneuvers. The goal is to achieve a 50 pct payload mass fraction. The proposed design requirements have several self-imposed constraints that define the vehicle and tube configurations. Structural considerations on the vehicle and tube wall dictate an upper acceleration limit of 1000 g's and a tube inside diameter of 1.0 m. In-tube propulsive requirements and vehicle structural constraints result in a vehicle diameter of 0.76 m, a total length of 7.5 m and a nose-cone half angle of 7 degrees. An ablating nose-cone constructed from carbon-carbon composite serves as the thermal protection mechanism for atmospheric transit.

  1. 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.

  2. Unified System of Mass, Energy, Space, and Time-MEST

    NASA Astrophysics Data System (ADS)

    Cao, Dayong

    2015-04-01

    Massenergy and spacetime build up a balance system of universe; massenergy equals negative spacetime. Like mass attract, opposite mass repel; like energy repel, opposite energy attract; like space attract, opposite space repel; like time repel, opposite time attract. The spacetime center of dark massenergy of dark hole system build up a balance system with the massenergy center of stellar matter. It explains of symmetry of CMB. According to observation of flat universe, cosmological constant of Einstein's equation is a negative Einstein's equation of structure of spacetime center which builds up a balance with Einstein's equation of the structure of massenergy center. According to Hubble's redshift equation, Hubble's redshift equals negative gravitational redshift which can be explained by negative Einstein's equation. The universe has 50% of Dark hole system and 50% of the stellar system which instead of 73% of dark energy, 23% of dark matter, and 4% of stellar matter and so on because dark energy and dark matter can be explained by dark massenergy of dark hole. The paper also supposes the black hole of the center of galaxy equals the dark hole, and a dark hole builds up a balance system with sun. The quantum balance systemic equation: E +E' ψ = mc2 +m' ψc'2 = 0 ,(c'2 = -(∂x) 2/(∂t) 2) . http://meeting.aps.org/link/BAPS.2015.MAR.Z23.14 http://meetings.aps.org/link/BAPS.2014.APR.Y9.1 http://meetings.aps.org/link/BAPS.2014.MAR.Y33.9 http://meetings.aps.org/link/BAPS.2010.DFD.QE.2

  3. Enhancing adoption of site-specific variable rate sprinkler systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    More than twenty years of private and public research on site-specific variable-rate sprinkler irrigation (SS-VRI) has resulted in very limited commercial adoption of the technology. Documented and proven water conservation strategies using site-specific irrigation are quite limited, and its cost-ef...

  4. Adoption of site-specific variable rate sprinkler irrigation systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    More than twenty years of private and public research on site-specific variable-rate sprinkler irrigation (SS-VRI) technology has resulted in limited commercial adoption of the technology. Competing patents, liability and proprietary software have affected industry’s willingness to move into a new t...

  5. Research and design of high speed mass image storage system

    NASA Astrophysics Data System (ADS)

    Li, Yu-feng; Xue, Rong-kun; Liang, Fei

    2009-07-01

    The design of the high mass image storage system is introduced using DSP, FPGA and Flash structure. Texas Instruments Corporation DSP chip (TMS320VC5509APEG) is used as the main controller, Samsung's Flash chips (K9F2G08U0M) used as the main storage medium, and the Xilinx Corporation FPGA chip (XCV600E) used as logic control modules. In this system, Storage module consists of 32 Flash memory chips, which are divided into 8 groups that correspond to 8-level pipeline. The 4-Flash memory chip forms a basic 32-bit memory module. The entire system storage space is 64 G bit. Through simulation and verification, the storage speed is up to 352Mbps and readout speed is up to 290Mbps, it can meet the demand to the high-speed access, and which has strong environmental adaptability.

  6. Sensitivity, specificity, and interobserver variability of survey thoracic radiography for the detection of heart base masses in dogs.

    PubMed

    Guglielmini, Carlo; Baron Toaldo, Marco; Quinci, Manuela; Romito, Giovanni; Luciani, Alessia; Cipone, Mario; Drigo, Michele; Diana, Alessia

    2016-06-15

    OBJECTIVE To determine the sensitivity, specificity, and interobserver variability of survey thoracic radiography (STR) for the detection of heart base masses (HBMs) in dogs. DESIGN Retrospective case-control study. ANIMALS 30 dogs with an HBM and 120 breed-matched control dogs (60 healthy dogs and 60 dogs with heart disease and no HBM). PROCEDURES In a blinded manner, 2 observers (designated as A and B) evaluated STR views from each dog for a mass-like opacity cranial to the heart, tracheal deviation, cardiomegaly, findings suggestive of pericardial effusion or right-sided congestive heart failure, and soft tissue opacities suggestive of pulmonary metastases. Investigators subsequently provided a final interpretation of each dog's HBM status (definitely affected, equivocal, or definitely not affected). RESULTS Considering equivocal interpretation as negative or positive for an HBM, the sensitivity of STR for diagnosis of an HBM was 40.0% (95% confidence interval [CI], 22.5% to 57.5%) and 56.7% (95% CI, 38.9% to 74.4%), respectively, for observer A and 63% (95% CI, 46.1% to 80.6%) and 80.0% (95% CI, 65.7% to 94.3%), respectively, for observer B. The corresponding specificity was 96.7% (95% CI, 93.5% to 99.9%) and 92.5% (95% CI, 87.8% to 97.2%), respectively, for observer A and 99.2% (95% CI, 97.5% to 100%) and 92.5% (95% CI, 87.8% to 97.2%), respectively, for observer B. The presence of a mass-like opacity cranial to the heart or tracheal deviation, or both, was significantly associated with a true diagnosis of HBM. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that STR is a highly specific but not a highly sensitive predictor of HBM in dogs. PMID:27270062

  7. Sensitivity, specificity, and interobserver variability of survey thoracic radiography for the detection of heart base masses in dogs.

    PubMed

    Guglielmini, Carlo; Baron Toaldo, Marco; Quinci, Manuela; Romito, Giovanni; Luciani, Alessia; Cipone, Mario; Drigo, Michele; Diana, Alessia

    2016-06-15

    OBJECTIVE To determine the sensitivity, specificity, and interobserver variability of survey thoracic radiography (STR) for the detection of heart base masses (HBMs) in dogs. DESIGN Retrospective case-control study. ANIMALS 30 dogs with an HBM and 120 breed-matched control dogs (60 healthy dogs and 60 dogs with heart disease and no HBM). PROCEDURES In a blinded manner, 2 observers (designated as A and B) evaluated STR views from each dog for a mass-like opacity cranial to the heart, tracheal deviation, cardiomegaly, findings suggestive of pericardial effusion or right-sided congestive heart failure, and soft tissue opacities suggestive of pulmonary metastases. Investigators subsequently provided a final interpretation of each dog's HBM status (definitely affected, equivocal, or definitely not affected). RESULTS Considering equivocal interpretation as negative or positive for an HBM, the sensitivity of STR for diagnosis of an HBM was 40.0% (95% confidence interval [CI], 22.5% to 57.5%) and 56.7% (95% CI, 38.9% to 74.4%), respectively, for observer A and 63% (95% CI, 46.1% to 80.6%) and 80.0% (95% CI, 65.7% to 94.3%), respectively, for observer B. The corresponding specificity was 96.7% (95% CI, 93.5% to 99.9%) and 92.5% (95% CI, 87.8% to 97.2%), respectively, for observer A and 99.2% (95% CI, 97.5% to 100%) and 92.5% (95% CI, 87.8% to 97.2%), respectively, for observer B. The presence of a mass-like opacity cranial to the heart or tracheal deviation, or both, was significantly associated with a true diagnosis of HBM. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that STR is a highly specific but not a highly sensitive predictor of HBM in dogs.

  8. System and method of modulating electrical signals using photoconductive wide bandgap semiconductors as variable resistors

    DOEpatents

    Harris, John Richardson; Caporaso, George J; Sampayan, Stephen E

    2013-10-22

    A system and method for producing modulated electrical signals. The system uses a variable resistor having a photoconductive wide bandgap semiconductor material construction whose conduction response to changes in amplitude of incident radiation is substantially linear throughout a non-saturation region to enable operation in non-avalanche mode. The system also includes a modulated radiation source, such as a modulated laser, for producing amplitude-modulated radiation with which to direct upon the variable resistor and modulate its conduction response. A voltage source and an output port, are both operably connected to the variable resistor so that an electrical signal may be produced at the output port by way of the variable resistor, either generated by activation of the variable resistor or propagating through the variable resistor. In this manner, the electrical signal is modulated by the variable resistor so as to have a waveform substantially similar to the amplitude-modulated radiation.

  9. 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.

  10. The Mass Flux of Micrometeoroids Into the Saturnian System

    NASA Astrophysics Data System (ADS)

    Kempf, S.; Altobelli, N.; Horanyi, M.; Srama, R.

    2013-12-01

    The origin of Saturn's ring is still not known. There is an ongoing argument whether Saturn's rings are rather young or have been formed shortly after Saturn itself, simultaneously together with its satellites. The water-ice rings contain about 5% rocky material resulting from continuous meteoroid bombardment of the ring material with interplanetary micrometeoroids. Knowledge of the incoming mass flux would allow to estimate the ring's exposure time. Model calculations suggest exposure times of 10^8 years, implying a late ring formation. This scenario is problematic because the tidal disruption of a Mimas-sized moon or of a comet within the planet's Roche zone would lead to a much larger rock content as observed today. Here we report on the first direct measurements of the meteoroid flux into the Saturnian system by Cassini's Cosmic Dust Analyzer (CDA). We measured the impact speed vectors of about 100 extrinsic micrometeoroids with radii ≥ 2 μm and determined their orbital elements. On the basis of these measurements we estimated determined the mass flux into the Saturnian system. Our findings suggest a ring exposure time of approximately 4.5 billion years and is in support of an early ring generation from a proto-Titan during the formation of the Saturnian system.

  11. Parameter identification for active mass damper controlled systems

    NASA Astrophysics Data System (ADS)

    Chang, C. C.; Wang, J. F.; Lin, C. C.

    2016-09-01

    Active control systems have already been installed in real structures and are able to decrease the wind- and earthquake-induced responses, while the active mass damper (AMD) is one of the most popular types of such systems. In practice, an AMD is generally assembled in- situ along with the construction of a building. In such a case, the AMD and the building is coupled as an entire system. After the construction is completed, the dynamic properties of the AMD subsystem and the primary building itself are unknown and cannot be identified individually to verify their design demands. For this purpose, a methodology is developed to obtain the feedback gain of the AMD controller and the dynamic properties of the primary building based on the complex eigen-parameters of the coupled building-AMD system. By means of the theoretical derivation in state-space, the non-classical damping feature of the system is characterized. This methodology can be combined with any state-space based system identification technique as a procedure to achieve the goal on the basis of the acceleration measurements of the building-AMD system. Results from numerical verifications show that the procedure is capable of extracting parameters and is applicable for AMD implementation practices.

  12. Neutron-proton pairing correlations in odd mass systems

    SciTech Connect

    Fellah, M. Allal, N. H.; Oudih, M. R.

    2015-03-30

    An expression of the ground-state which describes odd mass systems within the BCS approach in the isovector neutron-proton pairing case is proposed using the blocked level technique. The gap equations as well as the energy expression are then derived. It is shown that they exactly generalize the expressions obtained in the pairing between like-particles case. The various gap parameters and the energy are then numerically studied as a function of the pairing-strength within the schematic one-level model.

  13. Acton mass flow system applied to PFBC feed

    NASA Technical Reports Server (NTRS)

    Homburg, E.

    1977-01-01

    Dense phase pneumatic conveying and the Acton Mass Flow concept are defined with emphasis on the specific advantages to the coal and dolomite feed to the Pressurized Fluidized Bed Combustor. The transport and feed functions are explored with a comparison of designing the process for a combined function or for individual functions. The equipment required to accomplish these functions is described together with a typical example of sizing and air or gas requirements. A general outline of the control system required to obtain a uniform feed rate is provided. The condition of the coal and dolomite and conveying gas as required to obtain reliable transport and feed will be discussed.

  14. 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.

  15. Instrumental-Variables Simultaneous Equations Model of Physical Activity and Body Mass Index: The Coronary Artery Risk Development in Young Adults (CARDIA) Study.

    PubMed

    Meyer, Katie A; Guilkey, David K; Tien, Hsiao-Chuen; Kiefe, Catarina I; Popkin, Barry M; Gordon-Larsen, Penny

    2016-09-15

    We used full-system-estimation instrumental-variables simultaneous equations modeling (IV-SEM) to examine physical activity relative to body mass index (BMI; weight (kg)/height (m)(2)) using 25 years of data (1985/1986 to 2010/2011) from the Coronary Artery Risk Development in Young Adults (CARDIA) Study (n = 5,115; ages 18-30 years at enrollment). Neighborhood environment and sociodemographic instruments were used to characterize physical activity, fast-food consumption, smoking, alcohol consumption, marriage, and childbearing (women) and to predict BMI using semiparametric full-information maximum likelihood estimation to control for unobserved time-invariant and time-varying residual confounding and differential measurement error through model-derived discrete random effects. Comparing robust-variance ordinary least squares, random-effects regression, fixed-effects regression, single-equation-estimation IV-SEM, and full-system-estimation IV-SEM, estimates from random- and fixed-effects models and the full-system-estimation IV-SEM were unexpectedly similar, despite the lack of control for residual confounding with the random-effects estimator. Ordinary least squares tended to overstate the significance of health behaviors in BMI, while results from single-equation-estimation IV-SEM were notably different, revealing the impact of weak instruments in standard instrumental-variable methods. Our robust findings for fixed effects (which does not require instruments but has a high cost in lost degrees of freedom) and full-system-estimation IV-SEM (vs. standard IV-SEM) demonstrate potential for a full-system-estimation IV-SEM method even with weak instruments. PMID:27614300

  16. Breaking Gaussian incompatibility on continuous variable quantum systems

    SciTech Connect

    Heinosaari, Teiko; Kiukas, Jukka; Schultz, Jussi

    2015-08-15

    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.

  17. Design of a Ram Accelerator mass launch system

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The Ram Accelerator, a chemically propelled, impulsive mass launch system, is presented as a viable concept for directly launching acceleration-insensitive payloads into low Earth orbit. The principles of propulsion are based on those of an airbreathing supersonic ramjet. The payload vehicle acts as the ramjet centerbody and travels through a fixed launch tube that acts as the ramjet outer cowling. The launch tube is filled with premixed gaseous fuel and oxidizer mixtures that combust at the base of the vehicle and produce thrust. Two modes of in-tube propulsion involving ramjet cycles are used in sequence to accelerate the vehicle from 0.7 km/sec to 9 km/sec. Requirements for placing a 2000 kg vehicle into a 500-km circular orbit, with a minimum amount of onboard rocket propellant for orbital maneuvers, are examined. It is shown that in-tube propulsion requirements dictate a launch tube length of 5.1 km to achieve an exit velocity of 9 km/sec, with peak accelerations not to exceed 1000 g's. Aerodynamic heating due to atmospheric transit requires minimal ablative protection and the vehicle retains a large percentage of its exit velocity. An indirect orbital insertion maneuver with aerobraking and two apogee burns is examined to minimize the required onboard propellant mass. An appropriate onboard propulsion system design to perform the required orbital maneuvers with minimum mass requirements is also determined. The structural designs of both the launch tube and the payload vehicle are examined using simple structural and finite element analysis for various materials.

  18. 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.

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

    DOEpatents

    Frank, Andrew A.

    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. Automated spike preparation system for Isotope Dilution Mass Spectrometry (IDMS)

    SciTech Connect

    Maxwell, S.L. III; Clark, J.P.

    1990-12-31

    Isotope Dilution Mass Spectrometry (IDMS) is a method frequently employed to measure dissolved, irradiated nuclear materials. A known quantity of a unique isotope of the element to be measured (referred to as the ``spike``) is added to the solution containing the analyte. The resulting solution is chemically purified then analyzed by mass spectrometry. By measuring the magnitude of the response for each isotope and the response for the ``unique spike`` then relating this to the known quantity of the ``spike``, the quantity of the nuclear material can be determined. An automated spike preparation system was developed at the Savannah River Site (SRS) to dispense spikes for use in IDMS analytical methods. Prior to this development, technicians weighed each individual spike manually to achieve the accuracy required. This procedure was time-consuming and subjected the master stock solution to evaporation. The new system employs a high precision SMI Model 300 Unipump dispenser interfaced with an electronic balance and a portable Epson HX-20 notebook computer to automate spike preparation.

  1. Automated spike preparation system for Isotope Dilution Mass Spectrometry (IDMS)

    SciTech Connect

    Maxwell, S.L. III; Clark, J.P.

    1990-01-01

    Isotope Dilution Mass Spectrometry (IDMS) is a method frequently employed to measure dissolved, irradiated nuclear materials. A known quantity of a unique isotope of the element to be measured (referred to as the spike'') is added to the solution containing the analyte. The resulting solution is chemically purified then analyzed by mass spectrometry. By measuring the magnitude of the response for each isotope and the response for the unique spike'' then relating this to the known quantity of the spike'', the quantity of the nuclear material can be determined. An automated spike preparation system was developed at the Savannah River Site (SRS) to dispense spikes for use in IDMS analytical methods. Prior to this development, technicians weighed each individual spike manually to achieve the accuracy required. This procedure was time-consuming and subjected the master stock solution to evaporation. The new system employs a high precision SMI Model 300 Unipump dispenser interfaced with an electronic balance and a portable Epson HX-20 notebook computer to automate spike preparation.

  2. The mass flux of micrometeoroids into the Saturnian system

    NASA Astrophysics Data System (ADS)

    Kempf, S.; Altobelli, N.; Horanyi, M.; Srama, R.

    2014-04-01

    There is an ongoing debate about the age of Saturn's rings being: a) rather young, or b) formed contemporaneously with the planet and its satellites. The waterice rings contain about 5% of rocky material, originating from the continuous bombardment of the rings by interplanetary micrometeoroids. Knowledge of the incoming mass flux would allow to estimate the ring's exposure time. Model calculations suggest exposure times of 108 years, implying a late ring formation. This scenario is problematic because, for example, the tidal disruption of a Mimas-sized moon or of a comet within the planet's Roche zone would lead to a much larger rock content than observed today. Here we report on the first direct measurement of the meteoroid flux into the Saturnian system by Cassini's Cosmic Dust Analyzer (CDA).We measured the impact velocity vectors of about 140 extrinsic micrometeoroids with radii ≥ 2μm, and determined their orbital elements. On the basis of these measurements we determined the mass flux into the Saturnian system. Our findings suggest a ring exposure time of 4.5 billion years and is in support of an early ring formation scenario.

  3. 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.

  4. Computing probability masses in rule-based systems

    SciTech Connect

    Dillard, R.A.

    1982-09-01

    This report describes a method of computing confidences in rule-based inference systems by using the Dempster-Shafter theory. The theory is applicable to tactical decision problems which can be formulated in terms of sets of exhaustive and mutually exclusive propositions. Dempster's combining procedure, a generalization of Bayesian inference, can be used to combine probability mass assignments supplied by independent bodies of evidence. This report describes the use of Dempster's combining method and Shafer's representation framework in rule-based inference systems. It is shown that many kinds of data fusion problems can be represented in a way such that the constraints are met. Although computational problems remain to be solved, the theory should provide a versatile and consistent way of combining confidences for a large class of inferencing problems.

  5. Computer-Aided Diagnostic System For Mass Survey Chest Images

    NASA Astrophysics Data System (ADS)

    Yasuda, Yoshizumi; Kinoshita, Yasuhiro; Emori, Yasufumi; Yoshimura, Hitoshi

    1988-06-01

    In order to support screening of chest radiographs on mass survey, a computer-aided diagnostic system that automatically detects abnormality of candidate images using a digital image analysis technique has been developed. Extracting boundary lines of lung fields and examining their shapes allowed various kind of abnormalities to be detected. Correction and expansion were facilitated by describing the system control, image analysis control and judgement of abnormality in the rule type programing language. In the experiments using typical samples of student's radiograms, good results were obtained for the detection of abnormal shape of lung field, cardiac hypertrophy and scoliosis. As for the detection of diaphragmatic abnormality, relatively good results were obtained but further improvements will be necessary.

  6. Experimental investigation of a variable speed constant frequency electric generating system from a utility perspective

    NASA Technical Reports Server (NTRS)

    Herrera, J. I.; Reddoch, T. W.; Lawler, J. S.

    1985-01-01

    As efforts are accelerated to improve the overall capability and performance of wind electric systems, increased attention to variable speed configurations has developed. A number of potentially viable configurations have emerged. Various attributes of variable speed systems need to be carefully tested to evaluate their performance from the utility points of view. With this purpose, the NASA experimental variable speed constant frequency (VSCF) system has been tested. In order to determine the usefulness of these systems in utility applications, tests are required to resolve issues fundamental to electric utility systems. Legitimate questions exist regarding how variable speed generators will influence the performance of electric utility systems; therefore, tests from a utility perspective, have been performed on the VSCF system and an induction generator at an operating power level of 30 kW on a system rated at 200 kVA and 0.8 power factor.

  7. Experimental investigation of a variable speed constant frequency electric generating system from a utility perspective

    NASA Astrophysics Data System (ADS)

    Herrera, J. I.; Reddoch, T. W.; Lawler, J. S.

    1985-05-01

    As efforts are accelerated to improve the overall capability and performance of wind electric systems, increased attention to variable speed configurations has developed. A number of potentially viable configurations have emerged. Various attributes of variable speed systems need to be carefully tested to evaluate their performance from the utility points of view. With this purpose, the NASA experimental variable speed constant frequency (VSCF) system has been tested. In order to determine the usefulness of these systems in utility applications, tests are required to resolve issues fundamental to electric utility systems. Legitimate questions exist regarding how variable speed generators will influence the performance of electric utility systems; therefore, tests from a utility perspective, have been performed on the VSCF system and an induction generator at an operating power level of 30 kW on a system rated at 200 kVA and 0.8 power factor.

  8. Tree-ring inferred glacier mass balance variation in southeastern Tibetan Plateau and its linkage with climate variability

    NASA Astrophysics Data System (ADS)

    Duan, J.; Wang, L.; Li, L.; Sun, Y.

    2013-07-01

    A large number of glaciers in the Tibetan Plateau (TP) have experienced wastage in recent decades. And the wastage is different from region to region, even from glacier to glacier. A better understanding of long-term glacier variations and their linkage with climate variability requires extending the presently observed records. Here we present the first tree-ring-based glacier mass balance (MB) reconstruction in the TP, performed at the Hailuogou Glacier in southeastern TP during 1865-2007. The reconstructed MB is characterized mainly by ablation over the past 143 yr, and typical melting periods occurs in 1910s-1920s, 1930s-1960s, 1970s-1980s, and the last 20 yr. After the 1900s, only a few short periods (i.e., 1920s-1930s, the 1960s and the late 1980s) is characterized by accumulation. These variations can be validated by the terminus retreat velocity of the Hailuogou Glacier and the ice-core accumulation rate in Guliya and respond well to regional and Northern Hemisphere temperature anomaly. In addition, the reconstructed MB is significantly and negatively correlated with August-September all-Indian monsoon precipitation (AIR) (r1871-2008= -0.342, p < 0.0001). These results suggest that temperature variability is the dominant factor for the long-term MB variation at the Hailuogou Glacier. Indian summer monsoon precipitation doesn't affect the MB variation, yet the significant negative correlation between the MB and the AIR implies the positive effect of summer heating of the TP on Indian summer monsoon precipitation.

  9. Tree-ring-inferred glacier mass balance variation in southeastern Tibetan Plateau and its linkage with climate variability

    NASA Astrophysics Data System (ADS)

    Duan, J.; Wang, L.; Li, L.; Sun, Y.

    2013-11-01

    A large number of glaciers in the Tibetan Plateau (TP) have experienced wastage in recent decades. And the wastage is different from region to region, even from glacier to glacier. A better understanding of long-term glacier variations and their linkage with climate variability requires extending the presently observed records. Here we present the first tree-ring-based glacier mass balance (MB) reconstruction in the TP, performed at the Hailuogou Glacier in southeastern TP during 1868-2007. The reconstructed MB is characterized mainly by ablation over the past 140 yr, and typical melting periods occurred in 1910s-1920s, 1930s-1960s, 1970s-1980s, and the last 20 yr. After the 1900s, only a few short periods (i.e., 1920s-1930s, the 1960s and the late 1980s) were characterized by accumulation. These variations can be validated by the terminus retreat velocity of Hailuogou Glacier and the ice-core accumulation rate in Guliya and respond well to regional and Northern Hemisphere temperature anomaly. In addition, the reconstructed MB is significantly and negatively correlated with August-September all-India monsoon rainfall (AIR) (r1871-2008 = -0.342, p < 0.0001). These results suggest that temperature variability is the dominant factor for the long-term MB variation at the Hailuogou Glacier. Indian summer monsoon precipitation does not affect the MB variation, yet the significant negative correlation between the MB and the AIR implies the positive effect of summer heating of the TP on Indian summer monsoon precipitation.

  10. 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.

  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. Attenuating noise generated by variable-air-volume systems

    SciTech Connect

    Stokes, R.

    1985-03-01

    Sound generated by HVAC systems is receiving much attention because they are generally the principal contributors to room background sound levels that may become irritating and distracting noise if not controlled. This article discusses the creation of a quiet working environment through an analysis of the three traditional sound paths associated with air handling systems: radiated sound, inlet or return air sound and discharge sound. Recommended standards are given as well as a brief overview of materials used to fabricate HVAC system components.

  13. Variability of the thermohaline structure in the northern Veracruz Coral Reef System, Mexico

    NASA Astrophysics Data System (ADS)

    Mateos-Jasso, Adriana; Zavala-Hidalgo, Jorge; Romero-Centeno, Rosario; Allende-Arandía, María E.

    2012-12-01

    The variability of the thermohaline fields is studied at different time scales in the Veracruz Coral Reef System (VCRS) with hydrographic data from eleven CTD campaigns carried out from 2006 to 2010 and time series of temperature obtained from a mooring array (22 months) and from a current profiler (21 months). Results show that, from October to March, the vertical structure of temperature was quasi-homogeneous, with temperature differences between surface and bottom waters of less than 0.5 °C, and temperature inversions were frequently observed. By contrast, strong stratification was observed in late spring and summer when the surface—bottom temperature difference can be larger than 8 °C. In some years, the lower bottom temperatures were observed during summer. The lower temperatures of the 2007-2010 period were observed during winter 2010, being 2 °C to 4 °C lower than those observed in the previous years. It was also the year showing more temperature variability during the summer months due to several atmospheric tropical systems that affected the region, like tropical cyclone Alex. The dominant water mass at the VCRS observed during the study period was the Gulf Common Water, with salinities lower than 36.5 psu and temperatures between 21.2 °C and 30.0 °C. In addition, during summer, high temperature and low salinity water from local rivers was observed in the upper 6 m. During autumn-winter, low temperature and salinity waters coming from the northwestern shelves of the gulf were observed.

  14. 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

  15. Simulation of mass storage systems operating in a large data processing facility

    NASA Technical Reports Server (NTRS)

    Holmes, R.

    1972-01-01

    A mass storage simulation program was written to aid system designers in the design of a data processing facility. It acts as a tool for measuring the overall effect on the facility of on-line mass storage systems, and it provides the means of measuring and comparing the performance of competing mass storage systems. The performance of the simulation program is demonstrated.

  16. Evaluating preferred direction tropical cyclone track variability in an operational global ensemble prediction system

    NASA Astrophysics Data System (ADS)

    Elless, Travis J.

    Ensemble forecasts of Tropical Storm Debby and Hurricane Sandy (2012) highlight instances where variability in tropical cyclone (TC) position forecasts are stretched along a preferred direction. The goal of this thesis is to analyze this stretching of variability in a global ensemble prediction system, particularly the European Centre for Medium-Range Weather Forecasts (ECMWF), to determine how often and under what conditions does variability stretching occur, and ultimately what feature(s) are responsible for generating this variability. This study defines and evaluates preferred direction variability through a 2008--2012 global climatology of ECMWF TC position variability. A basin by basin comparison found stretching of the variability tends to occur most frequently in the West Pacific and least frequently in the Atlantic. Other forecast characteristics such as location, motion, and intensity are examined in each basin, and highlight midlatitude effects being associated with preferred direction variability. However, other features unique to each basin could also be playing a role in generating preferred direction variability. Possible sources of preferred direction variability are examined through a case study of ECMWF ensemble forecast initialized at 0000 UTC 24 June 2012 for Tropical Storm Debby. Zonal magnitude differences in Debby's steering layer wind are identified as the source for generating the associated variability stretching. Further evaluation however, cannot relate these differences to one feature, suggesting multiple processes are in play in generating preferred direction variability.

  17. Variable volume combustor with nested fuel manifold system

    DOEpatents

    McConnaughhay, Johnie Franklin; Keener, Christopher Paul; Johnson, Thomas Edward; Ostebee, Heath Michael

    2016-09-13

    The present application provides a combustor for use with a gas turbine engine. The combustor may include a number of micro-mixer fuel nozzles, a fuel manifold system in communication with the micro-mixer fuel nozzles to deliver a flow of fuel thereto, and a linear actuator to maneuver the micro-mixer fuel nozzles and the fuel manifold system.

  18. Influence of climate variability on water partitioning and effective energy and mass transfer in a semi-arid critical zone

    NASA Astrophysics Data System (ADS)

    Zapata-Rios, Xavier; Brooks, Paul D.; Troch, Peter A.; McIntosh, Jennifer; Rasmussen, Craig

    2016-03-01

    The critical zone (CZ) is the heterogeneous, near-surface layer of the planet that regulates life-sustaining resources. Previous research has demonstrated that a quantification of the influxes of effective energy and mass transfer (EEMT) to the CZ can predict its structure and function. In this study, we quantify how climate variability in the last 3 decades (1984-2012) has affected water availability and the temporal trends in EEMT. This study takes place in the 1200 km2 upper Jemez River basin in northern New Mexico. The analysis of climate, water availability, and EEMT was based on records from two high-elevation SNOTEL stations, PRISM data, catchment-scale discharge, and satellite-derived net primary productivity (MODIS). Results from this study indicated a decreasing trend in water availability, a reduction in forest productivity (4 g C m-2 per 10 mm of reduction in precipitation), and decreasing EEMT (1.2-1.3 MJ m2 decade-1). Although we do not know the timescales of CZ change, these results suggest an upward migration of CZ/ecosystem structure on the order of 100 m decade-1, and that decadal-scale differences in EEMT are similar to the differences between convergent/hydrologically subsidized and planar/divergent landscapes, which have been shown to be very different in vegetation and CZ structure.

  19. 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 (δ15N and δ13C) 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, δ15N and δ13C 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.

  20. Lumped mass formulations for modeling flexible body systems

    NASA Technical Reports Server (NTRS)

    Rampalli, Rajiv

    1989-01-01

    The efforts of Mechanical Dynamics, Inc. in obtaining a general formulation for flexible bodies in a multibody setting are discussed. The efforts being supported by MDI, both in house and externally are summarized. The feasibility of using lumped mass approaches to modeling flexibility in a multibody dynamics context is examined. The kinematics and kinetics for a simple system consisting of two rigid bodies connected together by an elastic beam are developed in detail. Accuracy, efficiency and ease of use using this approach are some of the issues that are then looked at. The formulation is then generalized to a superelement containing several nodes and connecting several bodies. Superelement kinematics and kinetics equations are developed. The feasibility and effectiveness of the method is illustrated by the use of some examples illustrating phenomena common in the context of spacecraft motions.

  1. 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.

  2. The model adaptive space shrinkage (MASS) approach: a new method for simultaneous variable selection and outlier detection based on model population analysis.

    PubMed

    Wen, Ming; Deng, Bai-Chuan; Cao, Dong-Sheng; Yun, Yong-Huan; Yang, Rui-Han; Lu, Hong-Mei; Liang, Yi-Zeng

    2016-10-01

    Variable selection and outlier detection are important processes in chemical modeling. Usually, they affect each other. Their performing orders also strongly affect the modeling results. Currently, many studies perform these processes separately and in different orders. In this study, we examined the interaction between outliers and variables and compared the modeling procedures performed with different orders of variable selection and outlier detection. Because the order of outlier detection and variable selection can affect the interpretation of the model, it is difficult to decide which order is preferable when the predictabilities (prediction error) of the different orders are relatively close. To address this problem, a simultaneous variable selection and outlier detection approach called Model Adaptive Space Shrinkage (MASS) was developed. This proposed approach is based on model population analysis (MPA). Through weighted binary matrix sampling (WBMS) from model space, a large number of partial least square (PLS) regression models were built, and the elite parts of the models were selected to statistically reassign the weight of each variable and sample. Then, the whole process was repeated until the weights of the variables and samples converged. Finally, MASS adaptively found a high performance model which consisted of the optimized variable subset and sample subset. The combination of these two subsets could be considered as the cleaned dataset used for chemical modeling. In the proposed approach, the problem of the order of variable selection and outlier detection is avoided. One near infrared spectroscopy (NIR) dataset and one quantitative structure-activity relationship (QSAR) dataset were used to test this approach. The result demonstrated that MASS is a useful method for data cleaning before building a predictive model. PMID:27435388

  3. The model adaptive space shrinkage (MASS) approach: a new method for simultaneous variable selection and outlier detection based on model population analysis.

    PubMed

    Wen, Ming; Deng, Bai-Chuan; Cao, Dong-Sheng; Yun, Yong-Huan; Yang, Rui-Han; Lu, Hong-Mei; Liang, Yi-Zeng

    2016-10-01

    Variable selection and outlier detection are important processes in chemical modeling. Usually, they affect each other. Their performing orders also strongly affect the modeling results. Currently, many studies perform these processes separately and in different orders. In this study, we examined the interaction between outliers and variables and compared the modeling procedures performed with different orders of variable selection and outlier detection. Because the order of outlier detection and variable selection can affect the interpretation of the model, it is difficult to decide which order is preferable when the predictabilities (prediction error) of the different orders are relatively close. To address this problem, a simultaneous variable selection and outlier detection approach called Model Adaptive Space Shrinkage (MASS) was developed. This proposed approach is based on model population analysis (MPA). Through weighted binary matrix sampling (WBMS) from model space, a large number of partial least square (PLS) regression models were built, and the elite parts of the models were selected to statistically reassign the weight of each variable and sample. Then, the whole process was repeated until the weights of the variables and samples converged. Finally, MASS adaptively found a high performance model which consisted of the optimized variable subset and sample subset. The combination of these two subsets could be considered as the cleaned dataset used for chemical modeling. In the proposed approach, the problem of the order of variable selection and outlier detection is avoided. One near infrared spectroscopy (NIR) dataset and one quantitative structure-activity relationship (QSAR) dataset were used to test this approach. The result demonstrated that MASS is a useful method for data cleaning before building a predictive model.

  4. Position-dependent mass, finite-gap systems, and supersymmetry

    NASA Astrophysics Data System (ADS)

    Bravo, Rafael; Plyushchay, Mikhail S.

    2016-05-01

    The ordering problem in quantum systems with position-dependent mass (PDM) is treated by inclusion of the classically fictitious similarity transformation into the kinetic term. This provides a generation of supersymmetry with the first-order supercharges from the kinetic term alone, while inclusion of the potential term allows us also to generate nonlinear supersymmetry with higher-order supercharges. A broad class of finite-gap systems with PDM is obtained by different reduction procedures, and general results on supersymmetry generation are applied to them. We show that elliptic finite-gap systems of Lamé and Darboux-Treibich-Verdier types can be obtained by reduction to Seiffert's spherical spiral and Bernoulli lemniscate in the presence of Calogero-like or harmonic oscillator potentials, or by angular momentum reduction of a free motion on some AdS2 -related surfaces in the presence of Aharonov-Bohm flux. The limiting cases include the Higgs and Mathews-Lakshmanan oscillator models as well as a reflectionless model with PDM exploited recently in the discussion of cosmological inflationary scenarios.

  5. Variable Delivery Systems for Peer Associated Token Reinforcement

    ERIC Educational Resources Information Center

    Edwards, Clifford H.

    1975-01-01

    This study focused on normal junior high school students in the natural school environment. Its purpose was to determine if different token delivery systems would differentially affect the disruptive behavior patterns of students in the normal classroom. (Author/RK)

  6. Diffusive limits of nonlinear hyperbolic systems with variable coefficients

    NASA Astrophysics Data System (ADS)

    Miyoshi, Hironari; Tsutsumi, Masayoshi

    2016-09-01

    We consider the initial-boundary value problem for a 2-speed system of first-order nonhomogeneous semilinear hyperbolic equations whose leading terms have a small positive parameter. Using energy estimates and a compactness lemma, we show that the diffusion limit of the sum of the solutions of the hyperbolic system, as the parameter tends to zero, verifies the nonlinear parabolic equation of the p-Laplacian type.

  7. Transient Finite Element Computations on a Variable Transputer System

    NASA Technical Reports Server (NTRS)

    Smolinski, Patrick J.; Lapczyk, Ireneusz

    1993-01-01

    A parallel program to analyze transient finite element problems was written and implemented on a system of transputer processors. The program uses the explicit time integration algorithm which eliminates the need for equation solving, making it more suitable for parallel computations. An interprocessor communication scheme was developed for arbitrary two dimensional grid processor configurations. Several 3-D problems were analyzed on a system with a small number of processors.

  8. 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.

  9. AGC 226067: A possible interacting low-mass system

    NASA Astrophysics Data System (ADS)

    Adams, E. A. K.; Cannon, J. M.; Rhode, K. L.; Janesh, W. F.; Janowiecki, S.; Leisman, L.; Giovanelli, R.; Haynes, M. P.; Oosterloo, T. A.; Salzer, J. J.; Zaidi, T.

    2015-08-01

    We present Arecibo, GBT, VLA, and WIYN/pODI observations of the ALFALFA source AGC 226067. Originally identified as an ultra-compact high velocity cloud and candidate Local Group galaxy, AGC 226067 is spatially and kinematically coincident with the Virgo cluster, and the identification by multiple groups of an optical counterpart with no resolved stars supports the interpretation that this systems lies at the Virgo distance (D = 17 Mpc). The combined observations reveal that the system consists of multiple components: a central H i source associated with the optical counterpart (AGC 226067), a smaller H i-only component (AGC 229490), a second optical component (AGC 229491), and extended low-surface brightness H i. Only ~1/4 of the single-dish H i emission is associated with AGC 226067; as a result, we find MHI/Lg ~ 6M⊙/L⊙ which is lower than previous work. At D = 17 Mpc, AGC 226067 has an H i mass of 1.5 × 107M⊙ and Lg = 2.4 × 106L⊙, AGC 229490 (the H i-only component) has MHI = 3.6 × 106M⊙, and AGC 229491 (the second optical component) has Lg = 3.6 × 105L⊙. The nature of this system of three sources is uncertain: AGC 226067 and AGC 229490 may be connected by an H i bridge, and AGC 229490 and AGC 229491 are separated by only 0.5'. The current data do not resolve the H i in AGC 229490 and its origin is unclear. We discuss possible scenarios for this system of objects: an interacting system of dwarf galaxies, accretion of material onto AGC 226067, or stripping of material from AGC 226067.

  10. Multiple and variable speed electrical generator systems for large wind turbines

    NASA Astrophysics Data System (ADS)

    Andersen, T. S.; Hughes, P. S.; Kirschbaum, H. S.; Mutone, G. A.

    A cost effective method to achieve increased wind turbine generator energy conversion and other operational benefits through variable speed operation is presented. Earlier studies of multiple and variable speed generators in wind turbines were extended for evaluation in the context of a specific large sized conceptual design. System design and simulation have defined the costs and performance benefits which can be expected from both two speed and variable speed configurations.

  11. Control design variable linking for optimization of structural/control systems

    NASA Technical Reports Server (NTRS)

    Jin, I. M.; Schmit, L. A.

    1991-01-01

    In this study a method is presented to integrate the design space of structural/control system optimization problems in the case of state feedback control. Conventional structural sizing variables and elements of the feedback gain matrix are both treated as strictly independent design variables in the optimization by extending design variable linking concepts to the control gains. Examples which involve a variety of behavior constraints, including dynamic transient response and control force limits, are effectively solved by using the method presented.

  12. 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.

  13. 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 μm

    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-μm 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-μm particles.

  14. AN INCREASE IN THE MASS OF PLANETARY SYSTEMS AROUND LOWER-MASS STARS

    SciTech Connect

    Mulders, Gijs D.; Pascucci, Ilaria; Apai, Dániel

    2015-12-01

    Trends in the planet population with host star mass provide an avenue to constrain planet formation theories. We derive the planet radius distribution function for Kepler stars of different spectral types, sampling a range in host star masses. We find that M dwarf stars have 3.5 times more small planets (1.0–2.8 R{sub ⨁}) than main-sequence FGK stars, but two times fewer Neptune-sized and larger (>2.8 R{sub ⨁}) planets. We find no systematic trend in the planet size distribution between spectral types F, G, and K to explain the increasing occurrence rates. Taking into account the mass–radius relationship and heavy-element mass of observed exoplanets, and assuming those are independent of spectral type, we derive the inventory of the heavy-element mass locked up in exoplanets at short orbits. The overall higher planet occurrence rates around M stars are not consistent with the redistribution of the same mass into more, smaller planets. At the orbital periods and planet radii where Kepler observations are complete for all spectral types, the average heavy-element mass locked up in exoplanets increases roughly inversely with stellar mass from 4 M{sub ⨁} in F stars to 5 M{sub ⨁} in G and K stars to 7 M{sub ⨁} in M stars. This trend stands in stark contrast with observed protoplanetary disk masses that decrease toward lower mass stars, and provides a challenge for current planet formation models. Neither models of in situ formation nor migration of fully formed planets are consistent with these results. Instead, these results are indicative of large-scale inward migration of planetary building blocks—either through type-I migration or radial drift of dust grains—that is more efficient for lower mass stars, but does not result in significantly larger or smaller planets.

  15. What you must do for a quieter VAV system. [Variable air volume

    SciTech Connect

    Brandenburg, J.; Dudley, J.

    1982-04-01

    Application guidelines that incorporate acoustic considerations for variable air volume (VAV) ventilation systems are presented, ventilation system that save energy. Ideas discussed have a solid theoretical base and have been modified after experience with actual VAV systems. They represent the best applicational experience from more than 15,000 VAV system installations. How VAV noise sources are found, measured, and silenced is described.

  16. Tuned mass damping system for a pendulum in gravity and microgravity fields

    NASA Astrophysics Data System (ADS)

    Atour, Farah

    2016-07-01

    An electrodynamic tether is a simple idea, but one with an amazing number of uses. Electrodynamic tether is a long conductor wire that is attached to the satellite, which can act as a generator or motor, from its motion through the earth's magnetic field. And it has the potential to make space travel significantly cheaper. The lack of electrodynamic tether's widespread in common applications can be attributed to the variable Lorentz forces occuring on the tethers, which will cause them to oscillate and may go out of control, de-orbit the satellite and fall to Earth. A tuned mass damper system, for short refered as tilger, is suggested as damper of oscillations of tethers. A system composed of a tuned mass damper and a simple pendulum simulating the tether was therefore constructed. 350 sets of experimental trials were done on the system, while it was installed inside a drop tower capsule resting on the ground, in order to pick four optimum setup experiments that will undergo a series of microgravity experiments at the Bremen Drop Tower in Bremen, Germany. The GJU Bachelor Research students found that the oscillations of the simple pendulum will not be affected by the tilger during the free fall experiment, except if a feedback mechanism is installed between the simple pendulum and the tilger. In this case, the tilger will dampen the simple pendulum oscillations during free fall.

  17. 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.

  18. 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.

  19. 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)

  20. Deep brain transcranial magnetic stimulation using variable "Halo coil" system

    NASA Astrophysics Data System (ADS)

    Meng, Y.; Hadimani, R. L.; Crowther, L. J.; Xu, Z.; Qu, J.; Jiles, D. C.

    2015-05-01

    Transcranial Magnetic Stimulation has the potential to treat various neurological disorders non-invasively and safely. The "Halo coil" configuration can stimulate deeper regions of the brain with lower surface to deep-brain field ratio compared to other coil configurations. The existing "Halo coil" configuration is fixed and is limited in varying the site of stimulation in the brain. We have developed a new system based on the current "Halo coil" design along with a graphical user interface system that enables the larger coil to rotate along the transverse plane. The new system can also enable vertical movement of larger coil. Thus, this adjustable "Halo coil" configuration can stimulate different regions of the brain by adjusting the position and orientation of the larger coil on the head. We have calculated magnetic and electric fields inside a MRI-derived heterogeneous head model for various positions and orientations of the coil. We have also investigated the mechanical and thermal stability of the adjustable "Halo coil" configuration for various positions and orientations of the coil to ensure safe operation of the system.

  1. Variable configuration fiber optic laser doppler vibrometer system

    NASA Astrophysics Data System (ADS)

    Posada-Roman, Julio E.; Jackson, David A.; Garcia-Souto, Jose A.

    2016-06-01

    A multichannel heterodyne fiber optic vibrometer is demonstrated which can be operated at ranges in excess of 50 m. The system is designed to measure periodic signals, impacts, rotation, 3D strain, and vibration mapping. The displacement resolution of each channel exceeds 1 nm. The outputs from all channels are simultaneous, and the number of channels can be increased by using optical switches.

  2. The Validity of Individual Rorschach Variables: Systematic Reviews and Meta-Analyses of the Comprehensive System

    ERIC Educational Resources Information Center

    Mihura, Joni L.; Meyer, Gregory J.; Dumitrascu, Nicolae; Bombel, George

    2013-01-01

    We systematically evaluated the peer-reviewed Rorschach validity literature for the 65 main variables in the popular Comprehensive System (CS). Across 53 meta-analyses examining variables against externally assessed criteria (e.g., observer ratings, psychiatric diagnosis), the mean validity was r = 0.27 (k = 770) as compared to r = 0.08 (k = 386)…

  3. A Beta Index to Confirm Causal Directions in a Closed System of Five Variables.

    ERIC Educational Resources Information Center

    Nigro, George A.

    The beta coefficient of an intermediate variable in a causal direction remains relatively constant as other system variables are introduced and controlled in stepped regression, whereas that in the acausal direction changes noticeably. Normalized random numbers (200x5) were generated and substituted in interdependent equations to produce five…

  4. THE INFLUENCE OF VARIABLE ELIMINATION RATE AND BODY FAT MASS IN A PBPK MODEL FOR TCDD IN PREDICTING THE SERUM TCDD CONCENTRATIONS FROM VETERANS OF OPERATION RANCH HAND

    EPA Science Inventory

    The Influence of Variable Elimination Rate and Body Fat Mass in a PBPK Model for TCDD in Predicting the Serum TCDD Concentrations from Veterans of Operation Ranch Hand.
    C Emond1,2, LS Birnbaum2, JE Michalek3, MJ DeVito2
    1 National Research Council, National Academy of Scien...

  5. Healthy Life Style Behaviors of University Students of School of Physical Education and Sports in Terms of Body Mass Index and Other Variables

    ERIC Educational Resources Information Center

    Bozlar, Volkan; Arslanoglu, Cansel

    2016-01-01

    The aim of this study is to determine Healthy Lifestyle Behaviors of students in the Schools of Physical Education and Sport (SPES) utilizing Body Mass Index (BMI) and other various variables. The study is composed of 1,695 students studying in SPES, in 14 different universities across Turkey. It is made up of 1,067 male and 624 female students.…

  6. Synchronicity of Kuroshio Current and climate system variability since the Last Glacial Maximum

    NASA Astrophysics Data System (ADS)

    Zheng, Xufeng; Li, Anchun; Kao, ShuhJi; Gong, Xun; Frank, Martin; Kuhn, Gerhard; Cai, Wenju; Yan, Hong; Wan, Shiming; Zhang, Honghai; Jiang, Fuqing; Hathorne, Edmund; Chen, Zhong; Hu, Bangqi

    2016-10-01

    The Kuroshio Current (KC) is the northward branch of the North Pacific subtropical gyre (NPG) and exerts influence on the exchange of physical, chemical, and biological properties of downstream regions in the Pacific Ocean. Resolving long-term changes in the flow of the KC water masses is, therefore, crucial for advancing our understanding of the Pacific's role in global ocean and climate variability. Here, we reconstruct changes in KC dynamics over the past 20 ka based on grain-size spectra, clay mineral, and Sr-Nd isotope constraints of sediments from the northern Okinawa Trough. Combined with published sediment records surrounding the NPG, we suggest that the KC remained in the Okinawa Trough throughout the Last Glacial Maximum. Together with Earth-System-Model simulations, our results additionally indicate that KC intensified considerably during the early Holocene (EH). The synchronous establishment of the KC "water barrier" and the modern circulation pattern during the EH highstand shaped the sediment transport patterns. This is ascribed to the precession-induced increase in the occurrence of La Niña-like state and the strength of the East Asian summer monsoon. The synchronicity of the shifts in the intensity of the KC, Kuroshio extension, and El Niño/La Niña-Southern Oscillation (ENSO) variability may further indicate that the western branch of the NPG has been subject to basin-scale changes in wind stress curl over the North Pacific in response to low-latitude insolation. Superimposed on this long-term trend are high-amplitude, large century, and millennial-scale variations during last 5 ka, which are ascribed to the advent of modern ENSO when the equatorial oceans experienced stronger insolation during the boreal winter.

  7. Deep ocean mass fluxes in the coastal upwelling off Mauritania from 1988 to 2012: variability on seasonal to decadal timescales

    NASA Astrophysics Data System (ADS)

    Fischer, Gerhard; Romero, Oscar; Merkel, Ute; Donner, Barbara; Iversen, Morten; Nowald, Nico; Ratmeyer, Volker; Ruhland, Götz; Klann, Marco; Wefer, Gerold

    2016-05-01

    A more than two-decadal sediment trap record from the Eastern Boundary Upwelling Ecosystem (EBUE) off Cape Blanc, Mauritania, is analysed with respect to deep ocean mass fluxes, flux components and their variability on seasonal to decadal timescales. The total mass flux revealed interannual fluctuations which were superimposed by fluctuations on decadal timescales. High winter fluxes of biogenic silica (BSi), used as a measure of marine production (mostly by diatoms) largely correspond to a positive North Atlantic Oscillation (NAO) index (December-March). However, this relationship is weak. The highest positive BSi anomaly was in winter 2004-2005 when the NAO was in a neutral state. More episodic BSi sedimentation events occurred in several summer seasons between 2001 and 2005, when the previous winter NAO was neutral or even negative. We suggest that distinct dust outbreaks and deposition in the surface ocean in winter and occasionally in summer/autumn enhanced particle sedimentation and carbon export on short timescales via the ballasting effect. Episodic perturbations of the marine carbon cycle by dust outbreaks (e.g. in 2005) might have weakened the relationships between fluxes and large-scale climatic oscillations. As phytoplankton biomass is high throughout the year, any dry (in winter) or wet (in summer) deposition of fine-grained dust particles is assumed to enhance the efficiency of the biological pump by incorporating dust into dense and fast settling organic-rich aggregates. A good correspondence between BSi and dust fluxes was observed for the dusty year 2005, following a period of rather dry conditions in the Sahara/Sahel region. Large changes of all bulk fluxes occurred during the strongest El Niño-Southern Oscillation (ENSO) in 1997-1999 where low fluxes were obtained for almost 1 year during the warm El Niño and high fluxes in the following cold La Niña phase. For decadal timescales, Bakun (1990) suggested an intensification of coastal upwelling

  8. Extending the Interdisciplinary Interfaces of Geomorphology by Changing the Units of Key Variables: From Volumes to Masses to Areas

    NASA Astrophysics Data System (ADS)

    Yoo, K.; Aufdenkampe, A. K.; Weinman, B. A.; Mudd, S. M.; Chen, C.

    2010-12-01

    such as (bio)geochemistry, environmental chemistry, hydrology, and carbon cycle could be well characterized in the efforts to convert the units of key variables from volumes to masses to surface areas. To illustrate this proposal, we present data from the actively eroding hillslopes in the Feather River, Sierra Nevada, CA, Piedmont soils from PA, and forest soils in northern Minnesota.

  9. Deep ocean mass fluxes in the coastal upwelling off Mauritania from 1988 to 2012: variability on seasonal to decadal timescales

    NASA Astrophysics Data System (ADS)

    Fischer, G.; Romero, O.; Merkel, U.; Donner, B.; Iversen, M.; Nowald, N.; Ratmeyer, V.; Ruhland, G.; Klann, M.; Wefer, G.

    2015-11-01

    A more than two-decadal sediment trap record from the Eastern Boundary Upwelling Ecosystem (EBUE) off Cape Blanc, Mauritania, is analyzed with respect to deep ocean mass fluxes, flux components and their variability on seasonal to decadal timescales. The total mass flux revealed interannual fluctuations which were superimposed by fluctuations on decadal timescales possibly linked to the Atlantic Multidedadal Oscillation (AMO). High winter fluxes of biogenic silica (BSi), used as a measure of marine production mostly by diatoms largely correspond to a positive North Atlantic Oscillation (NAO) index during boreal winter (December-March). However, this relationship is weak. The highest positive BSi anomaly was in winter 2004-2005 when the NAO was in a neutral state. More episodic BSi sedimentation events occurred in several summer seasons between 2001 and 2005, when the previous winter NAO was neutral or even negative. We suggest that distinct dust outbreaks and deposition in the surface ocean in winter but also in summer/fall enhanced particle sedimentation and carbon export on rather short timescales via the ballasting effect, thus leading to these episodic sedimentation events. Episodic perturbations of the marine carbon cycle by dust outbreaks (e.g. in 2005) weakened the relationships between fluxes and larger scale climatic oscillations. As phytoplankton biomass is high throughout the year in our study area, any dry (in winter) or wet (in summer) deposition of fine-grained dust particles is assumed to enhance the efficiency of the biological pump by being incorporated into dense and fast settling organic-rich aggregates. A good correspondence between BSi and dust fluxes was observed for the dusty year 2005, following a period of rather dry conditions in the Sahara/Sahel region. Large changes of all fluxes occurred during the strongest El Niño-Southern Oscillation (ENSO) in 1997-1999 where low fluxes were obtained for almost one year during the warm El Niño and

  10. Topological gaps without masses in driven graphene-like systems

    NASA Astrophysics Data System (ADS)

    Iadecola, Thomas; Neupert, Titus; Chamon, Claudio

    2014-03-01

    We illustrate the possibility of realizing band gaps in graphene-like systems that fall outside the existing classification of gapped Dirac Hamiltonians in terms of masses. As our primary example we consider a band gap arising due to time-dependent distortions of the honeycomb lattice. By means of an exact, invertible, and transport-preserving mapping to a time-independent Hamiltonian, we show that the system exhibits Chern-insulating phases with quantized Hall conductivities +/-e2 / h . The chirality of the corresponding gapless edge modes is controllable by both the frequency of the driving and the manner in which sublattice symmetry is broken by the dynamical lattice modulations. We demonstrate that, while these phases are in the same topological sector as the Haldane model, they are nevertheless separated from the latter by a gap-closing transition unless an extra parameter is added to the Hamiltonian. Finally, we discuss a promising possible realization of this physics in photonic lattices. This work is supported in part by DOE Grant DEF-06ER46316 (T.I. and C.C.).

  11. [Preparedness of health system in Israel for mass emergencies].

    PubMed

    Navrátil, Václav; Navrátil, Leoš

    2015-01-01

    The vast number of outbreaks of tension on the planet shows that it is impossible to underestimate the preparation level of population protection in emergencies. The possibility of a terrorist attack, including the use of particularly toxic or biological substances cannot be excluded or totally prevented at this point. In fact, there may not only be a terrorist attack. Rampant population migration increases the risk of the transmission of infectious diseases, even to considerable distances from the states where the epidemiological situation might not be completely under control. The current state of the Czech healthcare system in terms of preparedness for mass emergencies is insufficient and requires prompt correction, though not through hastily adopted measures. Ideally, looking into the success of the Israeli preparedness system, where the public has been exposed to high levels of threat from a variety of causes for decades, could greatly aid the Czech Republic in moving forward effectively. The number of victims of terrorist attacks there outpaces 10000, a fact that shows Israel is experienced in responding to emergency incidents. PMID:26311029

  12. Mass transport model through the skin by microencapsulation system.

    PubMed

    Carreras, Núria; Alonso, Cristina; Martí, Meritxell; Lis, Manel J

    2015-01-01

    Skin drug delivery can be subdivided into topical and transdermal administration. Transdermal administration can take advantage of chemical and physical strategies that can improve skin permeability and allow drug penetration. In this study, the development of a skin penetration profile was carried out by an in vitro technique for a microencapsulated system of ibuprofen. Release experiments were performed using percutaneous absorption tests to determine the evolution of the principle present in each of the different skin compartments as a function of time. A general kinetic model for a microencapsulated structure as a mass transport system through the skin was applied: [Formula: see text] This model could predict the penetration profile of encapsulated substances through skin from biofunctional textiles as well as estimate the dosage profile of the active principle. The apparent diffusion coefficients found were 1.20 × 10(-7 )cm/s for the stratum corneum and higher for the rest of the skin 6.67 × 10(-6 )cm/s. PMID:26004367

  13. System albedo as sensed by satellites - Its definition and variability

    NASA Technical Reports Server (NTRS)

    Hughes, N. A.; Henderson-Sellers, A.

    1982-01-01

    System albedo, an important climatological and environmental parameter, is considered. Some of the problems and assumptions involved in evaluating albedo from satellite data are discussed. Clear-sky and cloud albedos over the United Kingdom and parts of northwest Europe are treated. Consideration is given to the spectral, temporal, and spatial variations and the effect of averaging. The implications of these results for those using and archiving albedo values and for future monitoring of system albedo are discussed. Normalization is of especial importance since this correction alters many albedo values. The pronounced difference in spectral albedo of the two visible channels reemphasizes the problem of attempting to calculate integrated albedo values from meteorological satellite data. The assumption of isotropic reflection is seen to be invalid, hindering the computation of accurate albedo values.

  14. Self-Calibrating, Variable-Flow Pumping System

    NASA Technical Reports Server (NTRS)

    Walls, Joe T.

    1994-01-01

    Pumping system provides accurate, controlled flows of two chemical liquids mixed in spray head and react to form rigid or flexible polyurethane or polyisocyanurate foam. Compatible with currently used polyurethane-based coating materials and gas-bubble-forming agents (called "blowing agents" in industry) and expected to be compatible with materials that used in near future. Handles environmentally acceptable substitutes for chlorofluorocarbon foaming agents.

  15. Use of sunlight for plant lighting in a bioregenerative life support system Equivalent system mass calculations

    NASA Astrophysics Data System (ADS)

    Drysdale, Alan; Nakamura, Takashi; Yorio, Neil; Sager, John; Wheeler, Ray

    2008-12-01

    Plant lighting is a critical issue for cost effectiveness of bioregenerative systems. A plant lighting system using sunlight has been investigated and compared to systems using electrical lighting. Co-generation of electricity and use of in situ resource utilization (ISRU) were also considered. The fixed part of equivalent system mass was found to be reduced by factors of from 3.1 to 3.9, according to the mission assumptions. The time-dependent part of equivalent system mass was reduced by a smaller value, of about 1.05. Cost effectiveness of bioregeneration has been compared to the cost of shipping food. Break-even times for different Lunar and Mars missions were generally in the order of 2-10 years, and were quite sensitive to the assumptions. There is significant scope for future refinement of these values, and work is ongoing.

  16. 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.

  17. Biomek Cell Workstation: A Variable System for Automated Cell Cultivation.

    PubMed

    Lehmann, R; Severitt, J C; Roddelkopf, T; Junginger, S; Thurow, K

    2016-06-01

    Automated cell cultivation is an important tool for simplifying routine laboratory work. Automated methods are independent of skill levels and daily constitution of laboratory staff in combination with a constant quality and performance of the methods. The Biomek Cell Workstation was configured as a flexible and compatible system. The modified Biomek Cell Workstation enables the cultivation of adherent and suspension cells. Until now, no commercially available systems enabled the automated handling of both types of cells in one system. In particular, the automated cultivation of suspension cells in this form has not been published. The cell counts and viabilities were nonsignificantly decreased for cells cultivated in AutoFlasks in automated handling. The proliferation of manual and automated bioscreening by the WST-1 assay showed a nonsignificant lower proliferation of automatically disseminated cells associated with a mostly lower standard error. The disseminated suspension cell lines showed different pronounced proliferations in descending order, starting with Jurkat cells followed by SEM, Molt4, and RS4 cells having the lowest proliferation. In this respect, we successfully disseminated and screened suspension cells in an automated way. The automated cultivation and dissemination of a variety of suspension cells can replace the manual method.

  18. On comparison of SimTandem with state-of-the-art peptide identification tools, efficiency of precursor mass filter and dealing with variable modifications.

    PubMed

    Novák, Jiří; Sachsenberg, Timo; Hoksza, David; Skopal, Tomáš; Kohlbacher, Oliver

    2013-11-14

    The similarity search in theoretical mass spectra generated from protein sequence databases is a widely accepted approach for identification of peptides from query mass spectra produced by shotgun proteomics. Growing protein sequence databases and noisy query spectra demand database indexing techniques and better similarity measures for the comparison of theoretical spectra against query spectra. We employ a modification of previously proposed parameterized Hausdorff distance for comparisons of mass spectra. The new distance outperforms the original distance, the angle distance and state-of-the-art peptide identification tools OMSSA and X!Tandem in the number of identified peptides even though the q-value is only 0.001. When a precursor mass filter is used as a database indexing technique, our method outperforms OMSSA in the speed of search. When variable modifications are not searched, the search time is similar to X!Tandem. We show that the precursor mass filter is an efficient database indexing technique for high-accuracy data even though many variable modifications are being searched. We demonstrate that the number of identified peptides is bigger when variable modifications are searched separately by more search runs of a peptide identification engine. Otherwise, the false discovery rates are affected by mixing unmodified and modified spectra together resulting in a lower number of identified peptides. Our method is implemented in the freely available application SimTandem which can be used in the framework TOPP based on OpenMS.

  19. 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.

  20. Probing orientation of immobilized humanized anti-lysozyme variable fragment by time-of-flight secondary-ion mass spectrometry.

    PubMed

    Baio, J E; Cheng, Fang; Ratner, Daniel M; Stayton, Patrick S; Castner, David G

    2011-04-01

    As methods to orient proteins are conceived, techniques must also be developed that provide an accurate characterization of immobilized protein orientation. In this study, X-ray photoelectron spectroscopy (XPS), surface plasmon resonance (SPR), and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were used to probe the orientation of a surface immobilized variant of the humanized anti-lysozyme variable fragment (HuLys Fv, 26 kDa). This protein contained both a hexahistidine tag and a cysteine residue, introduced at opposite ends of the HuLys Fv, for immobilization onto nitrilotriacetic acid (NTA) and maleimide oligo(ethylene glycol) (MEG)-terminated substrates, respectively. The thiol group on the cysteine residue selectively binds to the MEG groups, while the his-tag selectively binds to the Ni-loaded NTA groups. XPS was used to monitor protein coverage on both surfaces by following the change in the nitrogen atomic %. SPR results showed a 10-fold difference in lysozyme binding between the two different HuLys Fv orientations. The ToF-SIMS data provided a clear differentiation between the two samples due to the intensity differences of secondary ions originating from asymmetrically located amino acids in HuLys Fv (histidine: 81, 82, and 110 m/z; phenylalanine: 120 and 131 m/z). An intensity ratio of the secondary ion peaks from the histidine and phenylalanine residues at either end of the protein was then calculated directly from the ToF-SIMS data. The 45% change in this ratio, observed between the NTA and MEG substrates with similar HuLys Fv surface coverages, indicates that the HuLys Fv fragment has opposite orientations on two different surfaces.

  1. Probing orientation of immobilized humanized anti-lysozyme variable fragment by time-of-flight secondary-ion mass spectrometry

    PubMed Central

    Baio, J. E.; Cheng, Fang; Ratner, Daniel M.; Stayton, Patrick S.; Castner, David G.

    2011-01-01

    As methods to orient proteins are conceived, techniques must also be developed that provide an accurate characterization of immobilized protein orientation. In this study, x-ray photoelectron spectroscopy (XPS), surface plasmon resonance, and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were used to probe the orientation of a surface immobilized variant of the humanized anti-lysozyme variable fragment (HuLys Fv, 26kDa). This protein contained both a his-tag and a cysteine residue, introduced at opposite ends of the HuLys Fv, for immobilization onto nitrilotriacetic acid (NTA) and maleimide oligo(ethylene glycol) (MEG) terminated substrates, respectively. The thiol group on the cysteine residue selectively binds to the MEG groups, while the his-tag selectively binds to the Ni loaded NTA groups. XPS was used to monitor protein coverage on both surfaces by following the change in the nitrogen atomic %. SPR results showed a 10-fold difference in lysozyme binding between the two different HuLys Fv orientations. The ToF-SIMS data provided a clear differentiation between the two samples due to the intensity differences of secondary ions originating from asymmetrically located amino acids in HuLys Fv (Histidine: 81, 82, and 110 m/z; Phenylalanine: 120 and 131 m/z). An intensity ratio of the secondary-ion peaks from the histidine and phenylalanine residues at either end of the protein was then calculated directly from the ToF-SIMS data. The 45% change in this ratio, observed between the NTA and MEG substrates with similar HuLys Fv surface coverages, indicates the HuLys Fv fragment has opposite orientations on the two different surfaces. PMID:21308984

  2. Holocene Sea Surface and Subsurface Water Mass Variability Reconstructed from Temperature and Sea-ice Proxies in Fram Strait

    NASA Astrophysics Data System (ADS)

    Werner, Kirstin; Spielhagen, Robert F.; Müller, Juliane; Husum, Katrine; Kandiano, Evgenia S.; Polyak, Leonid

    2016-04-01

    In two high-resolution sediment cores from the West Spitsbergen continental margin we investigated planktic foraminiferal, biomarker and dinocyst proxy data in order to reconstruct surface and subsurface water mass variability during the Holocene. The two study sites are today influenced by northward flowing warm and saline Atlantic Water. Both foraminiferal and dinocyst (de Vernal et al., 2013) temperature reconstructions indicate a less-stratified, ice-free, nutrient-rich summer surface ocean with strong Atlantic Water advection between 10.6 and 8.5 cal ka BP, likely related to maximum July insolation during the early Holocene. Sea surface to subsurface water temperatures of up to 6°C prevailed until ca 5 cal ka BP. A weakened contribution of Atlantic Water is found when subsurface temperatures strongly decreased with minimum values between ca 4 and 3 cal ka BP. High planktic foraminifer shell fragmentation and increased oxygen isotope values of the subpolar planktic foraminifer species Turborotalita quinqueloba as well as increasing concentrations of the sea ice biomarker IP25 further indicate cool conditions. Indices associated with IP25 as well as dinocyst data suggest a sustained cooling and consequently sea-ice increase during the late Holocene. However, planktic foraminiferal data indicate a slight return of stronger subsurface influx of Atlantic Water since ca 3 cal ka BP. The observed decoupling of cooling surface and warming subsurface waters during the later Holocene might be attributed to a strong pycnocline layer separating cold sea-ice fed surface waters from enhanced subsurface Atlantic Water advection. Reference: de Vernal, A., Hillaire-Marcel, C., Rochon, A., Fréchette, B., Henry, M., Solignac, S., Bonnet, S., 2013. Dinocyst-based reconstructions of sea ice cover concentration during the Holocene in the Arctic Ocean, the northern North Atlantic Ocean and its adjacent seas. Quaternary Science Reviews 79, 111-121.

  3. The distribution of mass and angular momentum in the solar system

    SciTech Connect

    Marochnik, L.S.; Mukhin, L.M.; Sagdeev, R.Z. )

    1989-01-01

    This book describes the contribution of the comets in the Oort cloud to the angular momentum of the solar system. Topics covered include: Nuclear mass of the new comets observed, Mass of the Oort cloud, Mass distribution in the solar system, Zone of comet formation, Angular momentum of the Oort cloud, and Angular momentum of the Hills cloud.

  4. 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-α, 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

  5. Time-Variable Phenomena in the Jovian System

    NASA Technical Reports Server (NTRS)

    Belton, Michael J. S. (Editor); West, Robert A. (Editor); Rahe, Jurgen (Editor); Pereyda, Margarita

    1989-01-01

    The current state of knowledge of dynamic processes in the Jovian system is assessed and summaries are provided of both theoretical and observational foundations upon which future research might be based. There are three sections: satellite phenomena and rings; magnetospheric phenomena, Io's torus, and aurorae; and atmospheric phenomena. Each chapter discusses time dependent theoretical framework for understanding and interpreting what is observed; others describe the evidence and nature of observed changes or their absence. A few chapters provide historical perspective and attempt to present a comprehensive synthesis of the current state of knowledge.

  6. High temperature VSCF (Variable Speed Constant Frequency) generator system

    NASA Astrophysics Data System (ADS)

    Maphet, Thomas Allen; McCabria, Jack Lee; Kouba, Carroll Charles; Mitchell, James Thomas; Kwiecinski, James Robert

    1989-04-01

    The high temperature VSCF generator program was designed to develop a generating system capable of withstanding constantly high oil-in temperatures of 200 C in an ambient environment of 200 C. This is a requirement due to anticipated new fighter aircraft designs that will not be capable of cooling the oil to 100 C as in today's designs due to size restrictions of the heat exchanger and/or extended operation of the aircraft at supersonic speeds. The generator uses composite material to withstand the constant use of 200 C inlet oil.

  7. Vibration characteristics of a cantilever plate with attached spring-mass system

    NASA Astrophysics Data System (ADS)

    Chiba, M.; Sugimoto, T.

    2003-02-01

    Coupled free vibration analysis has been performed on a cantilever thin plate carrying a spring-mass system attached on an arbitrary point by using Rayleigh-Ritz method. Influence of an attached 'spring-mass' system, i.e., attached position, relative values of mass and spring constant, on the coupled vibration characteristics of the system has been clarified comparing with those of uncoupled ones. Optimal attached position to maximize coupled plate natural frequency is also investigated and shown in contour diagrams. The influence of an attached mass has also been investigated, as the limiting case whereby the spring stiffness of the 'spring-mass' system approaches infinity.

  8. Embedded computer controlled premixing inline injection system for air-assisted variable-rate sprayers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Improvements to reduce chemical waste and environmental pollution for variable-rate sprayers used in orchards and ornamental nurseries require inline injection techniques. A microprocessor controlled premixing inline injection system implementing a ceramic piston chemical metering pump and two small...

  9. Method and system to estimate variables in an integrated gasification combined cycle (IGCC) plant

    DOEpatents

    Kumar, Aditya; Shi, Ruijie; Dokucu, Mustafa

    2013-09-17

    System and method to estimate variables in an integrated gasification combined cycle (IGCC) plant are provided. The system includes a sensor suite to measure respective plant input and output variables. An extended Kalman filter (EKF) receives sensed plant input variables and includes a dynamic model to generate a plurality of plant state estimates and a covariance matrix for the state estimates. A preemptive-constraining processor is configured to preemptively constrain the state estimates and covariance matrix to be free of constraint violations. A measurement-correction processor may be configured to correct constrained state estimates and a constrained covariance matrix based on processing of sensed plant output variables. The measurement-correction processor is coupled to update the dynamic model with corrected state estimates and a corrected covariance matrix. The updated dynamic model may be configured to estimate values for at least one plant variable not originally sensed by the sensor suite.

  10. 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.

  11. System for throttling and compensation for variable feedstock properties

    DOEpatents

    Meyer, John W.

    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.

  12. 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.

  13. Enhanced Recovery Utilizing Variable Frequency Drives and a Distributed Power System

    SciTech Connect

    Randy Peden; Sanjiv Shah

    2005-07-26

    This report describes complete results of the project entitled ''Enhanced Recovery Utilizing Variable Frequency Drives and a Distributed Power System''. This demonstration project was initiated in July 2003 and completed in March 2005. The objective of the project was to develop an integrated power production/variable frequency drive system that could easily be deployed in the oil field that would increase production and decrease operating costs. This report describes all the activities occurred and documents results of the demonstration.

  14. Response Surfaces for Key Controlled Variables in a Hybrid Solid Oxide Fuel Cell/Gas Turbine System

    SciTech Connect

    Rosen, William G; Banta, Larry; Gorrell, Megan; Restrepo, Bernardo; Tucker, David

    2012-07-01

    Hybrid generation systems have been extensively modeled as a first step toward the development of automatic controls for the system. In most cases, it is impossible to validate mathematical models against real hardware because only a handful of hardware systems exist in the world. Data taken from the existing hardware has demonstrated significant nonlinearity, complex coupling between controlled variables, and sometimes non-intuitive behavior. This work exploits the capability of the HyPer hardware test bed at the National Energy Technology Laboratory (NETL) to generate data from a real recuperated gas turbine coupled with hardware simulations of a fuel cell cathode and appropriate ancillary equipment. Prior work has characterized the system only over a limited range of its operating envelope, due to the inability to manipulate multiple control inputs simultaneously. The work presented here fills the gaps using data from a 34 factorial experiment to generate quasi-continuous response surfaces describing the operating state space of the HyPer system. Polynomial correlation functions have been fitted to the data with excellent agreement. Relationships between the control inputs and critical state variables such as cathode mass flow, cathode temperature, turbine inlet and exhaust temperatures and other key system parameters are presented.

  15. 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.

  16. Thermal energy storage system combining mass and PCM

    SciTech Connect

    Not Available

    1982-11-01

    The intent of this project was to construct several concrete blocks with PCM (Phase Change Material) encapsulated and to test these blocks as to heat transfer rate with and without a highly conductive matrix cast within the PCM core. The tests were to be conducted on commercially available PCM's being sold for solar applications. Unfortunately, one of the three PCM's was no longer produced commercially for sale and another would not crystallize as claimed by the manufacturer. This left one PCM, paraffin wax (the most critical to this work), to be tested. The testing showed that substantial improvement (18.5%) of heat conduction to the center of the paraffin core was obtainable with only a 2% loss of latent heat storage capacity. This finding may have a significant impact on the container designs for hydrocarbon heat storage system by showing that reduced surface to volume ratios can produce adequate heat transfer rates to the center of the PCM mass, without significant loss of performance.

  17. Short-term variability and mass loss in Be stars. II. Physical taxonomy of photometric variability observed by the Kepler spacecraft

    NASA Astrophysics Data System (ADS)

    Rivinius, Th.; Baade, D.; Carciofi, A. C.

    2016-09-01

    Context. Classical Be stars have been established as pulsating stars. Space-based photometric monitoring missions contributed significantly to that result. However, whether Be stars are just rapidly rotating SPB or β Cep stars, or whether they have to be understood differently, remains debated in the view of their highly complex power spectra. Aims: Kepler data of three known Be stars are re-visited to establish their pulsational nature and assess the properties of additional, non-pulsational variations. The three program stars turned out to be one inactive Be star, one active, continuously outbursting Be star, and one Be star transiting from a non-outbursting into an outbursting phase, thus forming an excellent sample to distill properties of Be stars in the various phases of their life-cycle. Methods: The Kepler data was first cleaned from any long-term variability with Lomb-Scargle based pre-whitening. Then a Lomb-Scargle analysis of the remaining short-term variations was compared to a wavelet analysis of the cleaned data. This offers a new view on the variability, as it enables us to see the temporal evolution of the variability and phase relations between supposed beating phenomena, which are typically not visualized in a Lomb-Scargle analysis. Results: The short-term photometric variability of Be stars must be disentangled into a stellar and a circumstellar part. The stellar part is on the whole not different from what is seen in non-Be stars. However, some of the observed phenomena might be to be due to resonant mode coupling, a mechanism not typically considered for B-type stars. Short-term circumstellar variability comes in the form of either a group of relatively well-defined, short-lived frequencies during outbursts, which are called Štefl frequencies, and broad bumps in the power spectra, indicating aperiodic variability on a time scale similar to typical low-order g-mode pulsation frequencies, rather than true periodicity. Conclusions: From a

  18. Variable cycle stirling engine and gas leakage control system therefor

    SciTech Connect

    Otters, J.

    1984-12-25

    An improved thermal engine of the type having a displacer body movable between the hot end and the cold end of a chamber for subjecting a fluid within that chamber to a thermodynamic cycle and having a work piston driven by the fluid for deriving a useful work output. The work piston pumps a hydraulic fluid and a hydraulic control valve is connected in line with the hydraulic output conduit such that the flow of hydraulic fluid may be restricted to any desired degree or stopped altogether. The work piston can therefore be controlled by means of a controller device independently from the movement of the displacer such that a variety of engine cycles can be obtained for optimum engine efficiency under varying load conditions. While a Stirling engine cycle is particularly contemplated, other engine cycles may be obtained by controlling the movement of the displacer and work pistons. Also disclosed are a working gas recovery system for controlling leakage of working gas from the displacer chamber, and a compound work piston arrangement for preventing leakage of hydraulic fluid around the work piston into the displacer chamber.

  19. Revised scaling variables in systems with many-body interactions

    NASA Astrophysics Data System (ADS)

    Goldstein, Raymond E.; Parola, Alberto

    1987-06-01

    Thermodynamic perturbation theory and the Kirkwood-Salsburg correlation function identities are used to study nearest-neighbor lattice gases with certain weak symmetry-breaking many-body interactions. It is shown that such systems may be mapped onto symmetric models by the introduction of suitable effective interactions and a shifted chemical potential, both of which depend explicitly on the temperature and fugacity of the original model. In the critical region, such a thermodynamic-state dependence implies the existence of a thermal scaling field which depends on the bare chemical potential, and this ``field mixing'' leads to a breakdown in the classical law of the rectilinear diameter. These results give a microscopic interpretation to a field-theoretic renormalization-group analysis which derives such a diameter singularity from the presence of terms cubic and higher in the order parameter and its gradients in an asymmetric Landau-Ginzburg-Wilson Hamiltonian. For a primarily repulsive three-body potential like the Axilrod-Teller interaction in classical insulating fluids, and in comparison with recent experiments, the analysis correctly describes the observed trends in the critical and near-critical behavior of the diameters with increasing particle polarizability.

  20. 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…

  1. Myological variability in a decoupled skeletal system: batoid cranial anatomy.

    PubMed

    Kolmann, Matthew A; Huber, Daniel R; Dean, Mason N; Grubbs, R Dean

    2014-08-01

    Chondrichthyans (sharks, batoids, and chimaeras) have simple feeding mechanisms owing to their relatively few cranial skeletal elements. However, the indirect association of the jaws to the cranium (euhyostylic jaw suspension) has resulted in myriad cranial muscle rearrangements of both the hyoid and mandibular elements. We examined the cranial musculature of an abbreviated phylogenetic representation of batoid fishes, including skates, guitarfishes and with a particular focus on stingrays. We identified homologous muscle groups across these taxa and describe changes in gross morphology across developmental and functional muscle groups, with the goal of exploring how decoupling of the jaws from the skull has effected muscular arrangement. In particular, we focus on the cranial anatomy of durophagous and nondurophagous batoids, as the former display marked differences in morphology compared to the latter. Durophagous stingrays are characterized by hypertrophied jaw adductors, reliance on pennate versus fusiform muscle fiber architecture, tendinous rather than aponeurotic muscle insertions, and an overall reduction in mandibular kinesis. Nondurophagous stingrays have muscles that rely on aponeurotic insertions onto the skeletal structure, and display musculoskeletal specialization for jaw protrusion and independent lower jaw kinesis, relative to durophagous stingrays. We find that among extant chondrichthyans, considerable variation exists in the hyoid and mandibular muscles, slightly less so in hypaxial muscles, whereas branchial muscles are overwhelmingly conserved. As chondrichthyans occupy a position sister to all other living gnathostomes, our understanding of the structure and function of early vertebrate feeding systems rests heavily on understanding chondrichthyan cranial anatomy. Our findings highlight the incredible variation in muscular complexity across chondrichthyans in general and batoids in particular.

  2. 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; Kong, Kyoungchul; 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.

  3. An expert system/ion trap mass spectrometry approach for life support systems monitoring

    NASA Technical Reports Server (NTRS)

    Palmer, Peter T.; Wong, Carla M.; Yost, Richard A.; Johnson, Jodie V.; Yates, Nathan A.; Story, Michael

    1992-01-01

    Efforts to develop sensor and control system technology to monitor air quality for life support have resulted in the development and preliminary testing of a concept based on expert systems and ion trap mass spectrometry (ITMS). An ITMS instrument provides the capability to identify and quantitate a large number of suspected contaminants at trace levels through the use of a variety of multidimensional experiments. An expert system provides specialized knowledge for control, analysis, and decision making. The system is intended for real-time, on-line, autonomous monitoring of air quality. The key characteristics of the system, performance data and analytical capabilities of the ITMS instrument, the design and operation of the expert system, and results from preliminary testing of the system for trace contaminant monitoring are described.

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

    PubMed

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

    2016-01-01

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

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

    PubMed

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

    2016-01-01

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

  6. Optimization of NTP System Truss to Reduce Radiation Shield Mass

    NASA Technical Reports Server (NTRS)

    Scharber, Luke L.; Kharofa, Adam; Caffrey, Jarvis A.

    2016-01-01

    The benefits of nuclear thermal propulsion are numerous and relevant to the current NASA mission goals involving but not limited to the crewed missions to mars and the moon. They do however also present new and unique challenges to the design and logistics of launching/operating spacecraft. One of these challenges, relevant to this discussion, is the significant mass of the shielding which is required to ensure an acceptable radiation environment for the spacecraft and crew. Efforts to reduce shielding mass are difficult to accomplish from material and geometric design points of the shield itself, however by increasing the distance between the nuclear engines and the main body of the spacecraft the required mass of the shielding is lessened considerably. The mass can be reduced significantly per unit length, though any additional mass added by the structure to create this distance serves to offset those savings, thus the design of a lightweight structure is ideal. The challenges of designing the truss are bounded by several limiting factors including; the loading conditions, the capabilities of the launch vehicle, and achieving the ideal truss length when factoring for the overall mass reduced. Determining the overall set of mass values for a truss of varying length is difficult since to maintain an optimally designed truss the geometry of the truss or its members must change. Thus the relation between truss mass and length for these loading scenarios is not linear, and instead has relation determined by the truss design. In order to establish a mass versus length trend for various truss designs to compare with the mass saved from the shield versus length, optimization software was used to find optimal geometric properties that still met the design requirements at established lengths. By solving for optimal designs at various lengths, mass trends could be determined. The initial design findings show a clear benefit to extending the engines as far from the main

  7. Variability study of the High Mass X-ray binary IGR J18027-2016 with Swift -XRT

    NASA Astrophysics Data System (ADS)

    Aftab, Nafisa; Islam, Nazma

    2016-07-01

    We report the results from pulsations and spectral analysis of a large number of observations of the HMXB pulsar IGR J18027-2016 with Swift-XRT,carried out at different orbital phases. We found a significant intensity variations in the system at different orbital phases, higher than the orbital intensity modulation. In some orbital phases, as seen in different XRT observations, the X-ray intensity is found to vary by a large factor, of about ˜50. In all the observations with sufficient number of source X-ray photons, pulsations have been detected around the previously known pulse period of ˜140 sec, consistent with the source being a persistent pulsator. The pulse profiles,however, show a significant change from a double peaked pulse profiles in most cases to a singled peaked pulse profiles in some observations. The nature of the pulse profiles are found to be independent of the X-ray intensity. In some of the observations, a 6.4 keV Fe Kα emission line is detected with a high equivalent width (˜1 keV). The absorption column density is found to be large before and after the eclipse, consistent with most of it being due to the stellar wind of the companion star. Such X-ray intensity variations outside the X-ray eclipse and associated spectral properties indicates a variable accretion onto the neutron star, which could be caused by a clumpy nature of the stellar wind of the companion star.

  8. 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.

  9. Lipidomics: a mass spectrometry based, systems level analysis of cellular lipids

    PubMed Central

    Ivanova, Pavlina T.; Milne, Stephen B.; Myers, David S.; Brown, H. Alex

    2009-01-01

    Lipidomics is a logical outcome of the history and traditions of lipid biochemistry and advances in mass spectrometry are at the heart of a renaissance in understanding the roles of lipids in cellular functions. Our desire to understand the complexity of lipids in biology has led to new techniques that allow us to identify over 1000 phospholipids in mammalian cell types and tissues. Improvements in chromatographic separation and mass spectrometry have positioned us to determine not only the lipid composition (i.e., parts list) of cells and tissues, but also address questions regarding lipid substrates and products that previously overwhelmed traditional analytical technologies. In the decade since lipidomics was conceived much of the efforts have been on new methodologies, development of computer programs to decipher the gigabytes of raw data, and struggling with the highly variable nature of biological systems where absolute quantities of a given metabolite may be less important than its relative change in concentration. It is clear that the technology is now sufficiently developed to address fundamental questions about the roles of lipids in cellular signaling and metabolic pathways. PMID:19744877

  10. On the use of the point-mass modeling technique for assessing ice-mass variations in alpine glacier systems

    NASA Astrophysics Data System (ADS)

    Reimond, Stefan; Baur, Oliver; Krauss, Sandro

    2016-04-01

    Most scientific studies dealing with gravity-based ice-mass balance estimations focus on the Earth's continental glacier systems, namely the Greenland and the Antarctica ice sheets. Alpine glacier regions such as the Alps, Himalaya or Patagonia, on the other hand, seem to be less considered. According to the most recent assessment report of the Intergovernmental Panel on Climate Change (IPCC), however, glacier shrinkage is one of the most dominant contributors to global sea level rise. In this context we investigate the capability of the point-mass modeling technique to assess ice-mass variations in small-scale alpine regions from space-borne gravimetric data. Two different approaches of this method can be distinguished: point-mass modeling with (i) predefined and fixed positions and (ii) with unknown locations of the surface mass changes. Approach (i) yields a linear functional model in which only the magnitudes of the point-masses are considered unknown. A highly non-linear optimization problem needs to be solved for approach (ii), since both the magnitudes and the coordinates of the point-masses are introduced as unknown parameters. In addition to that, owing to the effect of downward continuation, this problem is categorized as ill-posed and needs to be remedied by introducing regularization. The L-curve criterion or the generalized cross-validation method are typically used for selecting a suitable regularization factor. We conducted a series of close-loop simulation tests for various alpine glacier systems to compare the two approaches. In order to solve the global optimization problems in (i) and (ii), we make use of genetic algorithms.

  11. Phase variable type III restriction-modification systems of host-adapted bacterial pathogens.

    PubMed

    Fox, Kate L; Srikhanta, Yogitha N; Jennings, Michael P

    2007-09-01

    Phase variation, the high-frequency on/off switching of gene expression, is a common feature of host-adapted bacterial pathogens. Restriction-modification (R-M) systems, which are ubiquitous among bacteria, are classically assigned the role of cellular defence against invasion of foreign DNA. These enzymes are not obvious candidates for phase variable expression, a characteristic usually associated with surface-expressed molecules subject to host immune selection. Despite this, numerous type III R-M systems in bacterial pathogens contain repetitive DNA motifs that suggest the potential for phase variation. Several roles have been proposed for phase variable R-M systems based on DNA restriction function. However, there is now evidence in several important human pathogens, including Haemophilus influenzae, Neisseria meningitidis and Neisseria gonorrhoeae, that these systems are 'phasevarions' (phase variable regulons) controlling expression of multiple genes via a novel epigenetic mechanism. PMID:17714447

  12. 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.

  13. Controlling chaos in some laser systems via variable coupling and feedback time delays

    NASA Astrophysics Data System (ADS)

    Shahverdiev, E. M.

    2016-09-01

    We study numerically a system of two lasers cross-coupled optoelectronically with a time delay where the output intensity of each laser modulates the pump current of the other laser. We demonstrate control of chaos via variable coupling time delay by converting the laser intensity chaos to the steady-state. We also show that wavelength chaos in an electrically tunable distributed Bragg reflector (DBR) laser diode with a feedback loop that can be controlled via variable feedback time delay.

  14. Description and test results of a variable speed, constant frequency generating system

    NASA Technical Reports Server (NTRS)

    Brady, F. J.

    1985-01-01

    The variable-speed, constant frequency generating system developed for the Mod-0 wind turbine is presented. This report describes the system as it existed at the conclusion of the project. The cycloconverter control circuit is described including the addition of field-oriented control. The laboratory test and actual wind turbine test results are included.

  15. Variability in Chinese as a Foreign Language Learners' Development of the Chinese Numeral Classifier System

    ERIC Educational Resources Information Center

    Zhang, Jie; Lu, Xiaofei

    2013-01-01

    This study examined variability in Chinese as a Foreign Language (CFL) learners' development of the Chinese numeral classifier system from a dynamic systems approach. Our data consisted of a longitudinal corpus of 657 essays written by CFL learners at lower and higher intermediate levels and a corpus of 100 essays written by native speakers (NSs)…

  16. 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...

  17. Improving Flow Response of a Variable-rate Aerial Application System by Interactive Refinement

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Experiments were conducted to evaluate response of a variable-rate aerial application controller to changing flow rates and to improve its response at correspondingly varying system pressures. System improvements have been made by refinement of the control algorithms over time in collaboration with ...

  18. IDENTIFICATION OF A WIDE, LOW-MASS MULTIPLE SYSTEM CONTAINING THE BROWN DWARF 2MASS J0850359+105716

    SciTech Connect

    Faherty, Jacqueline K.; Burgasser, Adam J.; Bochanski, John J.; Looper, Dagny L.; West, Andrew A.; Van der Bliek, Nicole S.

    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.

  19. Reducing experimental variability in variance-based sensitivity analysis of biochemical reaction systems.

    PubMed

    Zhang, Hong-Xuan; Goutsias, John

    2011-03-21

    Sensitivity analysis is a valuable task for assessing the effects of biological variability on cellular behavior. Available techniques require knowledge of nominal parameter values, which cannot be determined accurately due to experimental uncertainty typical to problems of systems biology. As a consequence, the practical use of existing sensitivity analysis techniques may be seriously hampered by the effects of unpredictable experimental variability. To address this problem, we propose here a probabilistic approach to sensitivity analysis of biochemical reaction systems that explicitly models experimental variability and effectively reduces the impact of this type of uncertainty on the results. The proposed approach employs a recently introduced variance-based method to sensitivity analysis of biochemical reaction systems [Zhang et al., J. Chem. Phys. 134, 094101 (2009)] and leads to a technique that can be effectively used to accommodate appreciable levels of experimental variability. We discuss three numerical techniques for evaluating the sensitivity indices associated with the new method, which include Monte Carlo estimation, derivative approximation, and dimensionality reduction based on orthonormal Hermite approximation. By employing a computational model of the epidermal growth factor receptor signaling pathway, we demonstrate that the proposed technique can greatly reduce the effect of experimental variability on variance-based sensitivity analysis results. We expect that, in cases of appreciable experimental variability, the new method can lead to substantial improvements over existing sensitivity analysis techniques.

  20. Orbital Stability of Multi-planet Systems: Behavior at High Masses

    NASA Astrophysics Data System (ADS)

    Morrison, Sarah J.; Kratter, Kaitlin M.

    2016-06-01

    In the coming years, high-contrast imaging surveys are expected to reveal the characteristics of the population of wide-orbit, massive, exoplanets. To date, a handful of wide planetary mass companions are known, but only one such multi-planet system has been discovered: HR 8799. For low mass planetary systems, multi-planet interactions play an important role in setting system architecture. In this paper, we explore the stability of these high mass, multi-planet systems. While empirical relationships exist that predict how system stability scales with planet spacing at low masses, we show that extrapolating to super-Jupiter masses can lead to up to an order of magnitude overestimate of stability for massive, tightly packed systems. We show that at both low and high planet masses, overlapping mean-motion resonances trigger chaotic orbital evolution, which leads to system instability. We attribute some of the difference in behavior as a function of mass to the increasing importance of second order resonances at high planet–star mass ratios. We use our tailored high mass planet results to estimate the maximum number of planets that might reside in double component debris disk systems, whose gaps may indicate the presence of massive bodies.

  1. Orbital Stability of Multi-planet Systems: Behavior at High Masses

    NASA Astrophysics Data System (ADS)

    Morrison, Sarah J.; Kratter, Kaitlin M.

    2016-06-01

    In the coming years, high-contrast imaging surveys are expected to reveal the characteristics of the population of wide-orbit, massive, exoplanets. To date, a handful of wide planetary mass companions are known, but only one such multi-planet system has been discovered: HR 8799. For low mass planetary systems, multi-planet interactions play an important role in setting system architecture. In this paper, we explore the stability of these high mass, multi-planet systems. While empirical relationships exist that predict how system stability scales with planet spacing at low masses, we show that extrapolating to super-Jupiter masses can lead to up to an order of magnitude overestimate of stability for massive, tightly packed systems. We show that at both low and high planet masses, overlapping mean-motion resonances trigger chaotic orbital evolution, which leads to system instability. We attribute some of the difference in behavior as a function of mass to the increasing importance of second order resonances at high planet-star mass ratios. We use our tailored high mass planet results to estimate the maximum number of planets that might reside in double component debris disk systems, whose gaps may indicate the presence of massive bodies.

  2. Can the solar system planetary motion be used to forecast the multidecadal variability of climate?

    NASA Astrophysics Data System (ADS)

    Scafetta, N.

    2008-12-01

    Global warming has been and will be significantly modified by natural decadal-scale climate variability. For example, the pacific decadal oscillation (PDO) has entered a cool phase that is expected to induce a global cooling in the following two decades. A cooling of the global climate, not predicted by the Intergovernmental Panel on Climate Change (IPCC) projections, has been observed since 2002. The causes of the natural decadal and multidecadal scale climate fluctuations remain unexplained. This makes particularly problematic the evaluation of the climate models and of their theoretical forecasts for the 21st century. Here I investigate whether multidecadal internal climate variations are extraterrestrially induced. The movement of the Sun relative to the center of mass of the solar system (CMSS) is used as a proxy of the extraterrestrial forcing. I show that large natural climate variations with peak-to-trough amplitude of about 0.1 oC and 0.24 oC and with periods of about 20 and 60 years, respectively, match equivalent oscillations found in the dynamics of the Sun relative to the CMSS. Several other frequency components match as well. Thus, the solar planetary index can be used to forecast multidecadal natural climate oscillations for the 21st century. These projections indicate that climate will stabilize or cool until 2030. An indirect consequence of these findings is that at least 60% of the global warming observed since 1975 has been induced by the combined effect of the above two natural climate oscillations. This suggests that the anthropogenic effect on global warming has been exaggerated by the climate model simulations and projections published by the IPCC.

  3. The Formation Mass of a Binary System via Fragmentation of a Rotating Parent Core with Increasing Total Mass

    NASA Astrophysics Data System (ADS)

    Arreaga-García, G.

    2016-04-01

    We present a set of numerical simulations of the gravitational collapse of a uniform and rotating core, in which azimuthal symmetric mass seeds are initially implemented in order to favor the formation of a dense filament, out of which a binary system may be formed by direct fragmentation. We observe that this binary formation process is diminished when the total mass of the parent core M0 is increased; then we increase the level of the ratio of rotational energy to the gravitational energy, denoted by β, initially supplied to the rotating core, in order to achieve the desired direct fragmentation of the filament. We measure the binary mass Mf obtained from an initial M0 and then show a schematic diagram M0 vs β, where the desired binary configurations are located. We also report some basic physical data of the fragments.

  4. Optimal control of singularly perturbed nonlinear systems with state-variable inequality constraints

    NASA Technical Reports Server (NTRS)

    Calise, A. J.; Corban, J. E.

    1990-01-01

    The established necessary conditions for optimality in nonlinear control problems that involve state-variable inequality constraints are applied to a class of singularly perturbed systems. The distinguishing feature of this class of two-time-scale systems is a transformation of the state-variable inequality constraint, present in the full order problem, to a constraint involving states and controls in the reduced problem. It is shown that, when a state constraint is active in the reduced problem, the boundary layer problem can be of finite time in the stretched time variable. Thus, the usual requirement for asymptotic stability of the boundary layer system is not applicable, and cannot be used to construct approximate boundary layer solutions. Several alternative solution methods are explored and illustrated with simple examples.

  5. 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.

  6. 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…

  7. 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

  8. Modelling mass casualty decontamination systems informed by field exercise data.

    PubMed

    Egan, Joseph R; Amlôt, Richard

    2012-10-16

    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.

  9. 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

  10. MyNewsFlash: A System for Near Real-Time Variable Star Monitoring and Alerts

    NASA Astrophysics Data System (ADS)

    Price, A.; Turner, R.; Malatesta, K.; Simonsen, M. A.

    2004-12-01

    MyNewsFlash is an automated and customizable system for distributing timely variable star data. It supplies near real-time reports to the user of the latest activity of a variable star or class of stars. The stars it monitors, the frequency of report delivery, the delivery format, and more features are all completely customizable so the reader receives only reports of information he or she wants and nothing more or less. In addition, manually-generated alerts called Special MyNewsFlashes are occasionally sent out with additional information on special or abnormal behavior of a variable star. MyNewsFlash evolved from the AAVSO News Flash, an electronic publication dedicated to outbursts of popular cataclysmic variable stars

  11. Control design variable linking for optimization of structural/control systems

    NASA Technical Reports Server (NTRS)

    Jin, Ik Min; Schmit, Lucien A.

    1993-01-01

    A method is presented to integrate the design space of structural/control system optimization problems in the case of linear state feedback control. Conventional structural sizing variables and elements of the feedback gain matrix are both treated as strictly independent design variables in optimization by extending design variable linking concepts to the control gains. Several approximation concepts including new control design variable linking schemes are used to formulate the integrated structural/control optimization problem as a sequence of explicit nonlinear mathematical programming problems. Examples which involve a variety of behavior constraints, including constraints on dynamic stability, damped frequencies, control effort, peak transient displacement, acceleration, and control force limits, are effectively solved by using the method presented.

  12. 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.

  13. 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.

  14. The RenewElec Project: Variable Renewable Energy and the Power System

    SciTech Connect

    Apt, Jay

    2014-02-14

    Variable energy resources, such as wind power, now produce about 4% of U.S. electricity. They can play a significantly expanded role if the U.S. adopts a systems approach that considers affordability, security and reliability. Reaching a 20-30% renewable portfolio standard goal is possible, but not without changes in the management and regulation of the power system, including accurately assessing and preparing for the operational effects of renewable generation. The RenewElec project will help the nation make the transition to the use of significant amounts of electric generation from variable and intermittent sources of renewable power.

  15. Entanglement detection for bipartite systems with continuous variables in non-Markovian baths

    SciTech Connect

    Duan Hongguang; Liang Xianting

    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.

  16. 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.

  17. Low Mass Ratio Contact Binary Systems HN UMa and II UMa - III

    NASA Astrophysics Data System (ADS)

    Lee, Woo-Baik; Kim, Ho-Il; Kang, Young Woon; Oh, Kyu-Dong

    2006-09-01

    We present newly observed BVRI CCD light curves for low mass ratio contact binaries, HN UMa and II UMa. The absolute dimensions of these objects were obtained by applying the Wilson-Devinney program to previously published spectroscopic analysis and to our observed photometric data. The evolutionary status of all 21 low mass ratio contact binary system including HN UMa and II UMa was then considered. The secondaries of all low mass ratio contact binaries are located below the zero age main sequence in HR diagram. This phenomenon could be explained by mass loss from the secondary component in the low mass contact binary system because even small mass loss affects luminosity decrease in the low mass stars.

  18. Using expert systems to implement a semantic data model of a large mass storage system

    NASA Technical Reports Server (NTRS)

    Roelofs, Larry H.; Campbell, William J.

    1990-01-01

    The successful development of large volume data storage systems will depend not only on the ability of the designers to store data, but on the ability to manage such data once it is in the system. The hypothesis is that mass storage data management can only be implemented successfully based on highly intelligent meta data management services. There now exists a proposed mass store system standard proposed by the IEEE that addresses many of the issues related to the storage of large volumes of data, however, the model does not consider a major technical issue, namely the high level management of stored data. However, if the model were expanded to include the semantics and pragmatics of the data domain using a Semantic Data Model (SDM) concept, the result would be data that is expressive of the Intelligent Information Fusion (IIF) concept and also organized and classified in context to its use and purpose. The results are presented of a demonstration prototype SDM implemented using the expert system development tool NEXPERT OBJECT. In the prototype, a simple instance of a SDM was created to support a hypothetical application for the Earth Observing System, Data Information System (EOSDIS). The massive amounts of data that EOSDIS will manage requires the definition and design of a powerful information management system in order to support even the most basic needs of the project. The application domain is characterized by a semantic like network that represents the data content and the relationships between the data based on user views and the more generalized domain architectural view of the information world. The data in the domain are represented by objects that define classes, types and instances of the data. In addition, data properties are selectively inherited between parent and daughter relationships in the domain. Based on the SDM a simple information system design is developed from the low level data storage media, through record management and meta data

  19. 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.'

  20. Atmospheric Thickness Variability During Air Mass Conditions and Winter Snow Events at Albany, NY: 2002-2012

    NASA Astrophysics Data System (ADS)

    Dubbs, A. M.; Swift, S.; Godek, M. L.

    2014-12-01

    A winter weather parameter that is underutilized in the prediction of Northeast snowfall events is critical thickness. Knowledge of atmospheric thickness values during snowfall can benefit the accuracy of winter forecasts, especially if thickness layer ranges at times without precipitation are known. This investigation aims to better understand atmospheric thickness variations in the 1000-500, 1000-700, and 1000-850 hPa layers at Albany, New York during snowfall with differing air mass conditions. Since snow can occur alongside a variety of air mass environments, distinctions in layer thickness between air mass types and critical levels will be examined. Pairing air mass information with an improved understanding of thicknesses may allow forecasters to determine normal snowfall conditions of the atmosphere and decipher when anomalous conditions are occurring alongside heavier snows. Daily geopotential height data are examined alongside Spatial Synoptic Classification weather types over the past decade. Air mass frequencies are computed and baseline thicknesses are established for non-snow days, days with snow and liquid precipitation, and days with only snowfall. Thicknesses are compared to those computed for seven air mass types and differences layers are examined for continuity. For the three air masses identified as prevalent during heavy snow, light-to-heavy and early-to-late season snowfall categories are established and thickness variations are evaluated against non-snow days for significant differences. Results indicate that the differences in layer thicknesses are comparable for all precipitation and non-snow days but around 40 geopotential meters less for pure-snow days. For air masses present during snow, layer thicknesses can vary by over 100 gpm with type. Isolating polar varieties, approximately 50 gpm thickness differences are found in pure-snow days. Comparable differences are detected between the moderate and polar types and the continuity between