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. Global invariants for variable-mass systems.

    PubMed

    Howard, James E

    2006-10-20

    We investigate the effect of mass loss on the invariants of single particle motion in potentials having translational or rotational symmetry. These systems are non-Hamiltonian in the physical momenta, but for non-velocity-dependent potentials can be made formally Hamiltonian by treating the velocities as canonical momenta. Applying Noether's theorem to the formal Hamiltonian then yields global invariants corresponding to its symmetries. For velocity-dependent potentials, an exact invariant is constructed from the (non-Hamiltonian) vector field. The results are applied to charged particle motion in a magnetic dipole and agree well with numerical calculations. PMID:17155401

  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. 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…

  5. 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

  6. Atwood's machine as a tool to introduce variable mass systems

    NASA Astrophysics Data System (ADS)

    de Sousa, Célia A.

    2012-03-01

    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 ability needed to apply relevant concepts in situations not previously encountered. The pedagogical advantages are relevant for both secondary and high school students, showing that, through adequate examples, the question of the validity of Newton's second law may even be introduced to introductory level students.

  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. Deconstructed transverse mass variables

    NASA Astrophysics Data System (ADS)

    Ismail, Ahmed; Schwienhorst, Reinhard; Virzi, Joseph S.; Walker, Devin G. E.

    2015-04-01

    Traditional searches for R-parity conserving natural supersymmetry (SUSY) require large transverse mass and missing energy cuts to separate the signal from large backgrounds. SUSY models with compressed spectra inherently produce signal events with small amounts of missing energy that are hard to explore. We use this difficulty to motivate the construction of "deconstructed" transverse mass variables which are designed preserve information on both the norm and direction of the missing momentum. We demonstrate the effectiveness of these variables in searches for the pair production of supersymmetric top-quark partners which subsequently decay into a final state with an isolated lepton, jets and missing energy. We show that the use of deconstructed transverse mass variables extends the accessible compressed spectra parameter space beyond the region probed by traditional methods. The parameter space can further be expanded to neutralino masses that are larger than the difference between the stop and top masses. In addition, we also discuss how these variables allow for novel searches of single stop production, in order to directly probe unconstrained stealth stops in the small stop- and neutralino-mass regime. We also demonstrate the utility of these variables for generic gluino and stop searches in all-hadronic final states. Overall, we demonstrate that deconstructed transverse variables are essential to any search wanting to maximize signal separation from the background when the signal has undetected particles in the final state.

  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. PMID:21107425

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  12. 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 temperature. For the three types of MCS, it is shown that the variability of m(D) coefficients is correlated with the variability of the temperature and that the mass of ice hydrometeors for a given size decreases with decreasing temperature. Finally, the vertical variability of m(D) and PSD will be further differentiated, when separating the dataset horizontally with respect to the convective core of the MCS using the definition of a convective index.

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  14. 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

  15. DEEP, LOW MASS RATIO OVERCONTACT BINARY SYSTEMS. XIII. DZ PISCIUM WITH INTRINSIC LIGHT VARIABILITY

    SciTech Connect

    Yang, Y.-G.; Dai, H.-F.; Qian, S.-B.; Soonthornthum, B. E-mail: qsb@ynao.ac.cn

    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., LC{sub 2} 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{sub 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) Multiplication-Sign 10{sup -7} days yr{sup -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{sub spin}/J{sub orb} > 1/3.

  16. 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.

  17. 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.

  18. 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.

  19. Variability of Coronal Mass Ejections

    NASA Astrophysics Data System (ADS)

    Raychaudhuri, Probhas

    Coronal mass ejections (CME) from the solar corona are the most spectacular phenomena of solar activity. Solar physicists are tried to relate CME with other forms of solar activities. CMEs are the result of a large scale rearrangement of solar magnetic field and they are often observed as an eruption of twisted magnetic fields from the solar atmosphere. SOHO/LASCO detected (http://cdaw.gsfc.nasa.gov/CME_list) more than 7500 CMEs during 1996-2003 June. The catalog contains all the CMEs with primary characteristics e.g. linear speed, central position angle, and the angular width. We will use these characteristics to study the variations of CME within these periods. The period starts from the sunspot minimum to entire sunspot maximum range where the solar activity is high. Solar proton events ( E>10MeV) were collected from NOAA website (http:/www.lep.gsfc.nasa.gov/waves) of the associated CMEs with halo CMEs. We find from CMEs data that the occurrence of average CME rate is 121.51 per month during June 1999 to June 2003 (sunspot maximum range) whereas the occurrence of average CME rate is 41.24 per month during January 1996 to May 1999 (sunspot minimum range), although during the year 1996 (when the average sunspot number is 8.6 per month) occurrence of average CME rate is 18.16 per month. The CME occurrence rate is also correlated with the sunspot numbers with high statistically significant level. The CME number is highest in 2002 but CME is higher in 2000 than in 2001. There is an overall similarity between sunspot number and CME rates but there are differences particularly from June 1999 which is the beginning of the sunspot maximum range. The CME rate peaks in September 2001 to October 2002, which is about 1.25 year after the sunspot maximum. Similarly the average speed of CME at the time of sunspot maximum range and sunspot minimum range are 575 km/sec. and 266 km/sec. respectively. This means that the average speed of CME increases from 1996 to June 2003. The CME speed is also correlated with the sunspot numbers with less significant level than the average rate of CME occurrence. The maximum monthly average speed is about 677.3 km/sec. at the time of April 2001, which is about 5 months earlier than the second sunspot maximum. From the preliminary list of halo CME events from SOHO/LASCO during January 1996 to June 2003 we find that the occurrence rate of average halo CME events during January 1996 to May 1999 is about 1.10 per month whereas during June 1999 to June 2003 is about 4.00 per month, during the year 1996 only two halo CMEs is occurred. We also find that the average speed of halo CME events during sunspot minimum range is 838 km/sec, whereas average speed of the halo CME events during sunspot maximum range is 1000 km/sec. Although during the year 1996 the average speed of halo CME events is 451 km/sec. From the characteristics of halo CMEs in years we find that the number of halo CME increases from 1996 to 2001 and the number of halo CME is maximum in the year 2001, after that number of halo CME decreases. In the 23rd solar cycle maximum solar activity occurred during June to September 2001 we call the time as 2nd sunspot maximum time. We also find that number of high speed ( >1000 km/sec.) halo CME is highest during 2nd sunspot maximum range (i.e., during 2001-2002). We find from the halo CME data that average halo CME speed increases from 1996 to 1998 and then decreases from 1998 to 2000 and again increases from 2000 to 2003 and we expect that the average speed of halo CME will decrease after 2003. We find 78 solar proton events (E >10MeV) from CME and about 43 of them are from halo CME during 1996 to 2003. We noticed that the maximum solar proton events occurred at the second sunspot maximum, which is occurred after 1/12 sunspot maximum in the 23rd solar cycle. We find there exist 5 phases of solar proton events (E >10MeV) data in the 23rd solar cycle. The first phase is at the sunspot minimum, 2nd phase is after two years from the sunspot minimum, 3rd phase is at the time of sunspot maximum and 4th phase occurs just one and ha lf year (usually it is about 2/3 years) after the sunspot maximum and 5th phase occurs 2/3 years before the sunspot minimum. We find six solar proton events (E >10MeV) data within 1999 to 2003 with 12900 to 31700 pfu which produced strong geomagnetic storms and all of them are very high-speed halo CME. It is known that very fast CMEs >(Vp > 1000km/sec.) are capable of causing extremely intensive geomagnetic storm when Dst index < -300nT. We find that there is a significant correlation between the speed of the CME and solar proton events (E>10MeV) data. Solar radius measurement at Rio de Janeiro from 1997-2000 shows that the solar radius varies in phase with the solar cycle. Astrolabes of Antalya, Rio de Janeiro and Santiago suggest that the solar radius varies in phase with the solar cycle. From the detection of solar radius variations with MDI on board SOHO it is found that the solar radius increases with the number of sunspots[l]. It appears that solar radius variation and solar neutrino flux variation with the solar cycle is due to the variation of solar core pulsations and is mainly responsible for the variation of CME and its speed that is in phase with the solar cycle. We suggest that the above-mentioned characteristics are interrelated and that a pulsating solar core may be their common origin [2].

  20. Pulsational Mass Loss in Luminous Blue Variables

    NASA Astrophysics Data System (ADS)

    Lovekin, C. C.; Guzik, J. A.

    2012-12-01

    Luminous Blue Variables are evolved stars which experience periods of enhanced mass loss and outbursts. During these outbursts, the star stays at constant luminosity, but appears to become cooler. The S Doradus type variability, unlike the more extreme eruptions seen in η Car, occur on timescales of years to decades. The origin of the variability is still not understood, nor is the connection to extreme objects such as η Car. In this work, we examine hydrodynamic models of radial pulsation including time-dependent convection in massive stars, looking for the conditions necessary to trigger S Doradus type variability.

  1. Seasonal Variability of Greenland Ice Sheet Mass Balance

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

    The mass balance of the Greenland Ice Sheet (GrIS) is a substantial contributor to current and future sea level changes. Numerous studies have investigated annual to decadal changes in GrIS mass using observations and models, but have not focused on seasonal changes. We have evaluated the spatiotemporal variability of the GrIS mass balance at intra-annual timescales using mass changes derived from the Gravity Recovery and Climate Experiment (GRACE), surface mass balance from the Modèle Atmosphérique Régionale (MAR) regional climate model, and dynamic mass changes simulated by the Ice Sheet System Model (ISSM). Results from GRACE indicate a seasonal cycle of mass change that varies spatially across the ice sheet. Although net mass loss generally occurs during summer months and mass gain occurs during winter months, the timing of seasonal changes is spatially variable. In contrast, model results predict a seasonal cycle that is relatively consistent across time and space. Discrepancies between model predictions and GRACE results suggest that processes not captured by either MAR or ISSM (such as cycles of water storage and release, and seasonal variability of ice flow) play an important role in seasonal fluctuations of GrIS mass. Incorporating such processes into ice sheet models and/or climate models may be important for predicting future mass loss, and for understanding the spatiotemporal variability of discharge into the surrounding oceans.

  2. Scalar Gravitational Theory with Variable Rest Mass

    NASA Astrophysics Data System (ADS)

    Froedge, D. T.

    2007-04-01

    In this paper we will present the mechanical dynamics of a gravitational system resulting from a specific, rest mass, scalar potential relation, that is equivalent in predicting orbital and photon motion to that of General Relativity in the weak field solutions. The weak solutions of General Relativity do not appear to be contradicted by this development, and in this range the physical difference may not be measurable. The strong field solutions will be significantly different, however since, in this scalar relation, the rest mass goes to zero at Schwarzschild boundary. The consequences of the mass dependence gravitational potential results, for large masses, not in the prediction of black holes, but rather mass to Gamma ray converters. The theory would suggest that the defined gamma ray sources emissions of the galactic center imaged by the ESA/INTEGRAL spacecraft could be from bodies close to the maximum mass.

  3. 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 relevant timescales.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Variable mass unites Newtonian and GR gravity

    NASA Astrophysics Data System (ADS)

    Collins, Russell

    2000-03-01

    Newton's law of universal gravitation assumes constant mass. We have since learned that mass changes with speed (by SR) and also in the presence of a gravitational potential. This study examines the consequences of introducing these changes of mass into Newton's law. With 1/α ≡ (1+GM/rc^2), it follows that a rest mass, m0 in gravity-free space, increases to m^*=γ m_0/α =m_0/α^2 under free fall. This increase of mass results in a real contraction of the metric of length and time intervals: l^*=α^2 l and t^*=α^2 t. This scalar modification of Newtonian gravity easily and correctly accounts for the classical tests of GR, including starlight deflection, time delay for light transiting a gravitational region, and the precession rate of the perihelion of Mercury. It confirms the GR concept of non-Euclidean geometry in gravitational space, but the concept of black holes is not supported. Newtonian gravity is found to agree with experiment, requiring only that mass be correctly portrayed.

  9. 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 distribution of mass in the fuel tank or Solid Rocket Booster (SRB) case for various propellant levels. Based on the mass consumed by the liquid engine or SRB, the appropriate propellant model is coupled with the dry structure model for the stage. Then using vehicle configuration data, the integrated vehicle model is assembled and operated on by the constant system shape functions. The system mode shapes and frequencies can then be computed from the resulting generalized mass and stiffness matrices for that mass configuration. The rigid body mass properties of the vehicle are derived from the integrated vehicle model. The coupling terms between the vehicle rigid body motion and elastic deformation are also updated from the constant system shape functions and the integrated vehicle model. This approach was first used to analyze variable mass spinning beams and then prototyped into a generic dynamics simulation engine. The resulting code was tested against Crew Launch Vehicle (CLV-)class problems worked in the TREETOPS simulation package and by Wilson [2]. The Ares I System Integration Laboratory (SIL) is currently being developed at the Marshall Space Flight Center (MSFC) to test vehicle avionics hardware and software in a hardware-in-the-loop (HWIL) environment and certify that the integrated system is prepared for flight. The Ares I SIL utilizes the Ares Real-Time Environment for Modeling, Integration, and Simulation (ARTEMIS) tool to simulate the launch vehicle and stimulate avionics hardware. Due to the presence of vehicle control system filters and the thrust oscillation suppression system, which are tuned to the structural characteristics of the vehicle, ARTEMIS must incorporate accurate structural models of the Ares I launch vehicle. The ARTEMIS core dynamics simulation models the highly coupled nature of the vehicle flexible body dynamics, propellant slosh, and vehicle nozzle inertia effects combined with mass and flexible body properties that vary significant with time during the flight. All forces that act on the vehicle during flight must be simulated, including deflected engine thrust force, spatially distributed aerodynamic forces, gravity, and reaction control jet thrust forces. These forces are used to excite an integrated flexible vehicle, slosh, and nozzle dynamics model for the vehicle stack that simulates large rigid body translations and rotations along with small elastic deformations. Highly effective matrix math operations on a distributed, threaded high-performance simulation node allow ARTEMIS to retain up to 30 modes of flex for real-time simulation. Stage elements that separate from the stack during flight are propagated as independent rigid six degrees of freedom (6DOF) bodies. This paper will present the formulation of the resulting equations of motion, solutions to example problems, and describe the resulting dynamics simulation engine within ARTEMIS.

  10. 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.

  11. Mass-Losing Semiregular Variable Stars in Baade's Windows

    NASA Astrophysics Data System (ADS)

    Alves, D. R.; Glass, I. S.; MACHO and ISOGAL Collaborations

    1999-12-01

    MACHO Project V and R lightcurves and ISOGAL mid-infrared photometry (7 and 15 microns) are assembled for approximately 300 stars in Baade's Windows of low extinction towards the Galactic Bulge. These stars are primarily mass-losing giants of late M spectral type, and evolving along the asymptotic giant branch. The 7 micron flux from a late-type star with an optically thin, circumstellar dust shell arises from its photosphere, while the 15 micron flux is due to a combination of the photosphere and the dust. A tentative calibration of the ISOGAL photometry suggests that the stars in our sample exhibit a range of mass-loss rates from 10-7 to 10-9 solar masses per year. Using the MACHO lightcurves, we classify the majority of these stars as semiregular variables. This is the first large sample of semiregular variable stars whose pulsation and mass-loss rates are well-characterized, and whose distances, and thus energetics, are also known. In this preliminary report, we describe our search for periodic variability using the MACHO lightcurves. We find that luminosity, mass-loss rate, and pulsation period are correlated, in the sense that semiregulars with higher luminosities and higher mass-loss rates have longer periods. We note that this work is an example of data-mining in two large astronomical survey databases, which may become more common this century. This research was partially supported by a grant from NASA administered by the American Astronomical Society.

  12. 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.

  13. A Global Mass Circulation Variability and Annular Mode

    NASA Astrophysics Data System (ADS)

    Shin, C.; Cai, M.

    2009-12-01

    The simultaneous couplings among diabatic heating, meridional mass transport, meridional angular momentum transport, and form drag associated with amplifying baroclinic waves are diagnosed on isentropic surfaces using the NCEP-NCAR reanalysis II dataset from 1979 to 2003 for the Northern Hemisphere cold seasons. The objective of this study is to explain the dynamic nature of the annular mode from the perspective of global mass circulation variability. In the stratosphere, diabatic heating (cooling) anomalies in low (high) latitudes, prior to the polar stratospheric warming event are mainly determined by local radiative energy surplus (deficit) in low (high) latitudes. This meridional pattern of heating anomalies acts to strengthen the poleward advancement of air mass accompanied with a poleward angular momentum transport in the stratosphere. Form drag anomalies associated with amplifying baroclinic waves that transport both mass and angular momentum poleward in the extratropical portion of the global mass circulation act to reduce the westerly angular momentum accumulated during the poleward advancement of air mass by transferring the westerly angular momentum downward. The reduction of the westerly angular momentum helps the intensified poleward advancement of stratospheric air mass to expand gradually into higher latitudes. Moreover, the poleward advancement of air mass in the upper level is ahead of the lower level, implying a downward propagating signal in the stratosphere. During the polar stratospheric warming phase, the increase of air mass in the polar stratosphere due to the enhanced poleward warm air branch of the stratospheric mass circulation contributes to the rising of surface pressure in the polar region. Associated with a stronger poleward advancing of (upper) stratospheric air mass is a downward transferring of westerly angular momentum into lower stratosphere/upper troposphere in the extratropics. In addition to that acquired from the lower latitude, the westerly angular momentum transferred from stratosphere would hamper the development of the poleward warm air branch in the tropospheric mass circulation, explaining the lack of the poleward propagation signal in the troposphere. Arrival of poleward advancing warm air mass warms local air in high latitudes, resulting in heating anomalies there after the peak of the warming event. The enhanced mass exchange of lower latitude air mass with higher latitude air mass also results in a reduction of radiative heating in the tropics. The reversed diabatic heating anomalies, in turn, slow down the poleward advancement of air mass, responsible for the transition of the annular mode from the negative to the positive phase.

  14. Global Mass Circulation Variability associated with the Annular Mode

    NASA Astrophysics Data System (ADS)

    Shin, C.; Cai, M.

    2010-12-01

    The simultaneous couplings among diabatic heating, meridional mass transport, meridional angular momentum transport, and form drag associated with amplifying baroclinic waves are diagnosed on isentropic surfaces using the NCEP-NCAR reanalysis II dataset from 1979 to 2009 for the Northern Hemisphere cold seasons. The objective of this study is to explain the dynamic nature of the annular mode from the perspective of global mass circulation variability. In the stratosphere, diabatic heating (cooling) anomalies in low (high) latitudes, prior to the polar stratospheric warming event are mainly determined by local radiative energy surplus (deficit) in low (high) latitudes. This meridional pattern of heating anomalies acts to strengthen the poleward advancement of air mass accompanied with a poleward angular momentum transport in the stratosphere. Form drag anomalies associated with amplifying baroclinic waves that transport both mass and angular momentum poleward in the extratropical portion of the global mass circulation act to reduce the westerly angular momentum accumulated during the poleward advancement of air mass by transferring the westerly angular momentum downward. The reduction of the westerly angular momentum helps the intensified poleward advancement of stratospheric air mass to expand gradually into higher latitudes. Moreover, the poleward advancement of air mass in the upper level is ahead of the lower level, implying a downward propagating signal in the stratosphere. During the polar stratospheric warming phase, the increase of air mass in the polar stratosphere due to the enhanced poleward warm air branch of the stratospheric mass circulation contributes to the rising of surface pressure in the polar region. Associated with a stronger poleward advancing of (upper) stratospheric air mass is a downward transferring of westerly angular momentum into lower stratosphere/upper troposphere in the extratropics. In addition to that acquired from the lower latitude, the westerly angular momentum transferred from stratosphere would hamper the development of the poleward warm air branch in the tropospheric mass circulation, explaining the lack of the poleward propagation signal in the troposphere. Arrival of poleward advancing warm air mass warms local air in high latitudes, resulting in heating anomalies there after the peak of the warming event. The enhanced mass exchange of lower latitude air mass with higher latitude air mass also results in a reduction of radiative heating in the tropics. The reversed diabatic heating anomalies, in turn, slow down the poleward advancement of air mass, responsible for the transition of the annular mode from the negative to the positive phase.

  15. 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).

  16. 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.

  17. Spacecraft telecommunications system mass estimates

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

    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.

  18. Outbursts by low-mass white dwarfs in symbiotic variables

    NASA Technical Reports Server (NTRS)

    Sion, Edward M.; Ready, Christian J.

    1992-01-01

    The high-resolution IUE spectra of the symbiotic variables BF Cygni and EG Andromedae are studied in order to describe the P Cygni-like features of these objects. The 10 high-dispersion IUE spectra are examined for orbital phase-dependent variations in the C IV resonance doublet in terms of velocity and/or structure. One image is found to have a strong He-II absorption feature that coincides in velocity with the C-IV absorption component in P Cygni. The absorbing material for both lines is related to outflow and P Cygni self-absorption near the hot component. The P Cygni profiles do not appear to be related to a red-giant wind nor an expanding circumbinary shell in the in both BF Cyg and EG And. Quasi-static evolutionary model calculations demonstrate an unexpected outburst behavior in response to the assumed accretion. These data are shown to be important for the study of symbiotic systems that contain low-mass white dwarfs.

  19. 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.

  20. Spatial variability of Antarctic Peninsula net surface mass balance

    NASA Astrophysics Data System (ADS)

    Turner, J.; Lachlan-Cope, T. A.; Marshall, G. J.; Morris, E. M.; Mulvaney, R.; Winter, W.

    2002-07-01

    Measurements from ice cores and snow pits collected over the last 50 years are used to examine how net surface mass balance varies across the Antarctic Peninsula to give the first detailed map of mass balance for the region. A total of 211 reliable mass balance measurements were available for the preparation of the map, but some areas were found to be very data sparse. The analysis suggests that the largest values of mass balance are found along the spine of the northern part of the peninsula, where over 2.5 m yr-1 water equivalent (WE) has been measured. A secondary peak of more than 2.0 m yr-1 WE is determined along the mountains of eastern Alexander Island. Precipitation minus evaporation (P-E) fields from the European Centre for Medium-Range Weather Forecasts reanalysis project are compared with our analysis of in situ data. The model fields are found to have peak values of P-E of only half the amounts found from the measurements; the greatest model values are located on the western side of the peninsula. Areas where a high density of in situ data is available, including King George VI Sound and the high south central plateau part of the peninsula, show a high spatial variability of net surface mass balance, suggesting that local orographic features play a major part in dictating the mass balance.

  1. 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.

  2. 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.

  3. Guide to transverse projections and mass-constraining variables

    NASA Astrophysics Data System (ADS)

    Barr, A. J.; Khoo, T. J.; Konar, P.; Kong, K.; Lester, C. G.; 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 (mT, meff, mT2, missing p→T, hT, s^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 “p̸T”) 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 “⊤” from “∨” or from “∘,” 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 naïve 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.

  4. Cost and performance considerations for mass optical fiber splicing systems

    NASA Astrophysics Data System (ADS)

    Reinhardt, Joerg; Larson, Don

    1993-11-01

    This paper describes the cost and performance issues of mass splicing as compared to discrete fiber splicing. There are several variables in the telco decision to deploy mass splicing. Performance and cost factors for both mass mechanical and mass fusion are evaluated compared to currently available discrete fiber splicing technology. New mass splicing systems offer an attractive option for splicing cables of lower fiber counts than previously considered.

  5. 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.

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

    NASA Astrophysics Data System (ADS)

    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.

  7. 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.

  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. 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.

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

    NASA Astrophysics Data System (ADS)

    McHardy, I. M.

    2013-03-01

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

  11. 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.

  12. 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.

  13. 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.

  14. Jacobi Dynamics And The N-Body Problem With Variable Masses

    NASA Astrophysics Data System (ADS)

    Giordano, C. M.; Plastino, A. R.

    1999-11-01

    An appropriate generalization of the Jacobi equation of motion for the polar moment of inertia I is considered in order to study the N-body problem with variable masses. Two coupled ordinary differential equations governing the evolution of I and the total energy E are obtained. A regularization scheme for this system of differential equations is provided. We compute some illustrative numerical examples, and discuss an average method for obtaining approximate analytical solutions to this pair of equations. For a particular law of mass loss we also obtain exact analytical solutions. The application of these ideas to other kind of perturbed gravitational N-body systems involving drag forces or a different type of mass variation is also considered.

  15. 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.

  16. 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.

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

    PubMed

    Schock, M R

    1990-07-01

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

  18. 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.

  19. 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.

  20. Mass? What Mass? -Inertial Forces In Massless Systems

    NASA Astrophysics Data System (ADS)

    Johnson, John

    2015-04-01

    Inertial forces in massless systems are possible due to, of all things, simple propagation delays of the binding forces. Analysis at the classical level shows that in addition to intrinsic masses there are effective inertial mass contributions due to the interaction forces themselves. For 1/r potentials the effective mass is E/c2, but for more complex potentials this is not true. The general form of the effective mass term is shown, and in addition the inertial force density of an electromagnetic field is derived. While these analytical results are in the classical regime, it is argued that the retardation mechanism must apply to any interacting system of finite spatial extension. Doctorate, UM College Park, 1979.

  1. Low-mass Active Galactic Nuclei with Rapid X-Ray Variability

    NASA Astrophysics Data System (ADS)

    Ho, Luis C.; Kim, Minjin

    2016-04-01

    We present a detailed study of the optical spectroscopic properties of 12 active galactic nuclei (AGNs) with candidate low-mass black holes (BHs) selected by Kamizasa et al. through rapid X-ray variability. The high-quality, echellette Magellan spectra reveal broad Hα emission in all the sources, allowing us to estimate robust virial BH masses and Eddington ratios for this unique sample. We confirm that the sample contains low-mass BHs accreting at high rates: the median MBH = 1.2 × 106 M⊙ and median Lbol/LEdd = 0.44. The sample follows the MBH-σ* relation, within the considerable scatter typical of pseudobulges, the probable hosts of these low-mass AGNs. Various lines of evidence suggest that ongoing star formation is prevalent in these systems. We propose a new strategy to estimate star formation rates in AGNs hosted by low-mass, low-metallicity galaxies, based on modification of an existing method using the strength of [O II] λ3727, [O III] λ5007, and X-rays.

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

    NASA Technical Reports Server (NTRS)

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

    1973-01-01

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

  4. Variability in winter mass balance of Northern Hemisphere glaciers and relations with atmospheric circulation

    USGS Publications Warehouse

    McCabe, G.J.; Fountain, A.G.; Dyurgerov, M.

    2000-01-01

    An analysis of variability in the winter mass balance (WMB) of 22 glaciers in the Northern Hemisphere indicates two primary modes of variability that explain 46% of the variability among all glaciers. The first mode of variability characterizes WMB variability in Northern and Central Europe and the second mode primarily represents WMB variability in northwestern North America, but also is related to variability in WMB of one glacier in Europe and one in Central Asia. These two modes of WMB variability are explained by variations in mesoscale atmospheric circulation which are driving forces of variations in surface temperature and precipitation. The first mode is highly correlated with the Arctic Oscillation Index, whereas the second mode is highly correlated with the Southern Oscillation Index. In addition, the second mode of WMB variability is highly correlated with variability in global winter temperatures. This result suggests some connection between global temperature trends and WMB for some glaciers.

  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 present the development and testing of the VASC concept.

  6. 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.

  7. 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.

  8. Infrared Properties of Cataclysmic Variables from the 2MASS All-Sky Data Release

    NASA Astrophysics Data System (ADS)

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

    2003-12-01

    Because accretion-generated luminosity dominates the radiated energy of most cataclysmic variables (CVs), they have been ``traditionally'' observed primarily at short wavelengths. Consequently, relatively little is known about the infrared (IR) properties of CVs. Fortunately, advances in IR detector technology during the last decade have made this region of the spectrum much more accessible. Investigating CVs in the IR contributes to our understanding of the properties of key system components that radiate strongly at these wavelengths: the cool outer disk, accretion stream, and secondary star. We present the initial results of our investigation of the group IR properties of all CVs detected in the 2-Micron All Sky Survey (2MASS). 2MASS imaged the entire sky down to completeness limits of J=15.8, H=15.1, and Ks=14.3 mag (detection limits are approximately 0.8 mag fainter). The recent All-Sky Data Release from 2MASS allows us, for the first time, to compile and compare the homogenous JHKs photometry for the complete sample of known CVs. This work is an extension of our previous investigation of a subset of CVs using the 2MASS 2nd Incremental Data Release (Hoard et al. 2002, ApJ, 565, 511). This research has been accomplished as part of the SSC Visiting Graduate Student Program.

  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. 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.

  11. Temporal variability of mass transport in the Canary Current

    NASA Astrophysics Data System (ADS)

    Hernández-Guerra, A.; Machín, F.; Antoranz, A.; Cisneros-Aguirre, J.; Gordo, C.; Marrero-Díaz, A.; Martínez, A.; Ratsimandresy, A. W.; Rodríguez-Santana, A.; Sangrá, P.; López-Laazen, F.; Parrilla, G.; Pelegrí, J. L.

    The variability of the Canary Current is investigated using bimonthly expandable bathythermograph sections from Gran Canaria Island to the African coast between November 1996 and September 1998. The geostrophic transport of the easternmost branch of the Canary Current is estimated by integrating the thermal wind equation using the layer of neutral density 27.3 (roughly 600 m depth) as the layer of no motion. The yearly average geostrophic transport of this branch of the Canary Current is 1.8±1.4×10 9 kg s -1 southward. Approximately half of the transport flows through the channel between the islands of Gran Canaria and Fuerteventura, and the other half through the channel between Fuerteventura and the African coast. The total southward geostrophic transport shows significant seasonal variability, ranging from 1.2±0.3×10 9 kg s -1 in May to 2.6±0.1×10 9 kg s -1 in January, although November is the only month with considerable differences in geostrophic transport between 1996 and 1997. There is seasonal northward transport in both channels, during May in the Gran Canaria-Fuerteventura channel and during November in the Fuerteventura-African coast channel. This seasonal pattern is probably linked to autumn weakening of upwelling in the Canary Islands area and the offshore diversion of this flow at Cape Ghir.

  12. A study of variable thrust, variable specific impulse trajectories for solar system exploration

    NASA Astrophysics Data System (ADS)

    Sakai, Tadashi

    A study has been performed to determine the advantages and disadvantages of variable thrust and variable Isp (specific impulse) trajectories for solar system exploration. There have been several numerical research efforts for variable thrust, variable Isp, power-limited trajectory optimization problems. All of these results conclude that variable thrust, variable Isp (variable specific impulse, or VSI) engines are superior to constant thrust, constant Isp (constant specific impulse; or CSI) engines. However, most of these research efforts assume a mission from Earth to Mars, and some of them further assume that these planets are circular and coplanar. Hence they still lack the generality. This research has been conducted to answer the following questions: (1) Is a VSI engine always better than a CSI engine or a high thrust engine for any mission to any planet with any time of flight considering lower propellant mass as the sole criterion? (2) If a planetary swing-by is used for a VSI trajectory, is the fuel savings of a VSI swing-by trajectory better than that of a CSI swing-by or high thrust swing-by trajectory? To support this research, an unique, new computer-based interplanetary trajectory calculation program has been created. This program utilizes a calculus of variations algorithm to perform overall optimization of thrust, Isp, and thrust vector direction along a trajectory that minimizes fuel consumption for interplanetary travel. It is assumed that the propulsion system is power-limited, and thus the compromise between thrust and Isp is a variable to be optimized along the flight path. This program is capable of optimizing not only variable thrust trajectories but also constant thrust trajectories in 3-D space using a planetary ephemeris database. It is also capable of conducting planetary swing-bys. Using this program, various Earth-originating trajectories have been investigated and the optimized results have been compared to traditional CSI and high thrust trajectory solutions. Results show that VSI rocket engines reduce fuel requirements for any mission compared to CSI rocket engines. Fuel can be saved by applying swing-by maneuvers for VSI engines; but the effects of swing-bys due to VSI engines are smaller than that of CSI or high thrust engines.

  13. 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.

  14. Miniaturization of Mass Spectrometry Analysis Systems.

    PubMed

    Xu, Wei; Manicke, Nicholas E; Cooks, Graham R; Ouyang, Zheng

    2010-12-01

    The key concepts and technologies developed in our laboratories in Purdue University for the miniaturization of mass spectrometry analysis systems are introduced. Mass analyzers of simple geometries with a novel atmospheric pressure interface were employed allowed reduction in the size of the ion trap mass spectrometer. Ambient ionization methods were developed and coupled to miniature mass spectrometers to allow direct MS analysis of complex samples without sample preparation and chemical separation. The performance of desorption electrospray ionization, low temperature plasma probe, paper spray as well as two handheld MS systems, Mini 10 and Mini 11, are described with demonstrations of capabilities for chemical analysis. PMID:21278840

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

    NASA Astrophysics Data System (ADS)

    Rohn, Joachim; Vehling, Lucas; Moser, Michael

    2013-04-01

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

  16. Separability criteria for continuous-variable systems

    SciTech Connect

    Fujikawa, Kazuo

    2009-07-15

    A general separability condition on the second moment (covariance matrix) for continuous-variable two-party systems is derived by an analysis analogous to the derivation of Kennard's uncertainty relation without referring to the non-negativity of the partially transposed density matrix. This separability criterion is generally more stringent than that used by Simon which is based on the non-negativity of partially transposed density matrix, and thus this criterion may be useful in the analysis of general continuous two-party systems. Another separability criterion used by Duan et al. is shown to be generally weaker than that of Simon. We thus have a hierarchy of separability criterions, but all these criterions when combined with suitable squeezing become equivalent at the boundary of the P-representation condition and thus turned out to be sufficient to analyze the separability of two-party Gaussian systems.

  17. Variable Stars in the VVV Globular Clusters. I. 2MASS-GC 02 and Terzan 10

    NASA Astrophysics Data System (ADS)

    Alonso-García, Javier; Dékány, István; Catelan, Márcio; Contreras Ramos, Rodrigo; Gran, Felipe; Amigo, Pía; Leyton, Paul; Minniti, Dante

    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.

  18. 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.

  19. 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.

  20. Air Pressure Controlled Mass Measurement System

    NASA Astrophysics Data System (ADS)

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

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

  1. Gas sampling system for a mass spectrometer

    DOEpatents

    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.

  2. 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.

  3. 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.

  4. 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.

  5. X-ray spectral and variability properties of low-mass active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Ludlam, R. M.; Cackett, E. M.; Gültekin, K.; Fabian, A. C.; Gallo, L.; Miniutti, G.

    2015-03-01

    We study the X-ray properties of a sample of 14 optically selected low-mass active galactic nuclei (AGN) whose masses lie within the range 105-2 × 106 M⊙ with XMM-Newton. Only six of these low-mass AGN have previously been studied with sufficient quality X-ray data, thus, we have more than double the number of low-mass AGN observed by XMM-Newton with the addition of our sample. We analyse their X-ray spectral properties and variability and compare the results to their more massive counterparts. The presence of a soft X-ray excess is detectable in all five objects which were not background dominated at 2-3 keV. Combined with previous studies, this gives a total of eight low-mass AGN with a soft excess. The low-mass AGN exhibit rapid, short-term variability (hundreds to thousands of seconds) and long-term variability (months to years). There is a well-known anticorrelation between black hole mass and variability amplitude (normalized excess variance). Comparing our sample of low-mass AGN with this relation we find that all of our sample lie below an extrapolation of the linear relation. Such a flattening of the relation at low masses (below ˜106 M⊙) is expected if the variability in all AGN follows the same shape power spectrum with a break frequency that is dependent on mass. Finally, we also found two objects that show significant absorption in their X-ray spectrum, indicative of type 2 objects, although they are classified as type 1 AGN based on optical spectra.

  6. Variability in a Young, L/T Transition Planetary-mass Object

    NASA Astrophysics Data System (ADS)

    Biller, Beth A.; Vos, Johanna; Bonavita, Mariangela; Buenzli, Esther; Baxter, Claire; Crossfield, Ian J. M.; Allers, Katelyn; Liu, Michael C.; Bonnefoy, Mickaël; Deacon, Niall; Brandner, Wolfgang; Schlieder, Joshua E.; Dupuy, Trent; Kopytova, Taisiya; Manjavacas, Elena; Allard, France; Homeier, Derek; Henning, Thomas

    2015-11-01

    As part of our ongoing NTT SoFI survey for variability in young free-floating planets and low-mass brown dwarfs, we detect significant variability in the young, free-floating planetary-mass object PSO J318.5-22, likely due to rotational modulation of inhomogeneous cloud cover. A member of the 23 ± 3 Myr β Pic moving group, PSO J318.5-22 has Teff = {1160}-40+30 K and a mass estimate of 8.3 ± 0.5 MJup for a 23 ± 3 Myr age. PSO J318.5-22 is intermediate in mass between 51 Eri b and β Pic b, the two known exoplanet companions in the β Pic moving group. With variability amplitudes from 7% to 10% in JS at two separate epochs over 3-5 hr observations, we constrain the rotational period of this object to >5 hr. In KS, we marginally detect a variability trend of up to 3% over a 3 hr observation. This is the first detection of weather on an extrasolar planetary-mass object. Among L dwarfs surveyed at high photometric precision (<3%), this is the highest amplitude variability detection. Given the low surface gravity of this object, the high amplitude preliminarily suggests that such objects may be more variable than their high-mass counterparts, although observations of a larger sample are necessary to confirm this. Measuring similar variability for directly imaged planetary companions is possible with instruments such as SPHERE and GPI and will provide important constraints on formation. Measuring variability at multiple wavelengths can help constrain cloud structure. Based on observations made with ESO Telescopes at the La Silla Paranal Observatory under program ID 095.C-0590.

  7. A SEMI-EMPIRICAL MASS-LOSS RATE IN SHORT-PERIOD CATACLYSMIC VARIABLES

    SciTech Connect

    Sirotkin, Fedir V.; Kim, Woong-Tae E-mail: wkim@astro.snu.ac.k

    2010-10-01

    The mass-loss rate of donor stars in cataclysmic variables (CVs) is of paramount importance in the evolution of short-period CVs. Observed donors are oversized in comparison with those of isolated single stars of the same mass, which is thought to be a consequence of the mass loss. Using the empirical mass-radius relation of CVs and the homologous approximation for changes in effective temperature T{sub 2}, orbital period P, and luminosity of the donor with the stellar radius, we find the semi-empirical mass-loss rate M-dot{sub 2} of CVs as a function of P. The derived M-dot{sub 2} is at {approx}10{sup -9.5}-10{sup -10} M{sub sun} yr{sup -1} and weakly depends on P when P>90 minutes, while it declines very rapidly toward the minimum period when P < 90 minutes, emulating the P-T{sub 2} relation. Due to strong deviation from thermal equilibrium caused by the mass loss, the semi-empirical M-dot{sub 2} is significantly different from and has a less-pronounced turnaround behavior with P than suggested by previous numerical models. The semi-empirical P- M-dot{sub 2} relation is consistent with the angular momentum loss due to gravitational wave emission and strongly suggests that CV secondaries with 0.075 M{sub sun} < M{sub 2} < 0.2 M{sub sun} are less than 2 Gyr old. When applied to selected eclipsing CVs, our semi-empirical mass-loss rates are in good agreement with the accretion rates derived from the effective temperatures T{sub 1} of white dwarfs, suggesting that M-dot{sub 2} can be used to reliably infer T{sub 2} from T{sub 1}. Based on the semi-empirical M-dot{sub 2}, SDSS 1501 and 1433 systems that were previously identified as post-bounce CVs have yet to reach the minimal period.

  8. Line profile variability from tidal interactions in binary systems

    NASA Astrophysics Data System (ADS)

    Moreno, E.; Koenigsberger, G.; Toledano, O.

    2005-07-01

    We present the results of ab initio calculations of the photospheric line-profile variability produced by the tidal deformations in binary systems. We use the one-layer approximation to compute the effects produced on a primary star's equatorial region by its companion in the general case of arbitrary rotational velocity (V_eq), eccentricity and viscosity, ν. For an eccentric binary such as ɛ Per, the computed absorption lines display bumps that are superposed on the rotationally broadened profile and that travel from the blue side of the line towards the red, qualitatively similar to the observations. The strength and multiplicity of the bumps depend on orbital phase. In the case of binaries with circular orbits, non-synchronous rotation leads to strong profile variability which can be described in terms of inverted "S"-shape patterns in grey-scale representations of the variability. The radial velocity curves obtained by measuring the centroid of the varying line-profiles are distorted with respect to the true radial velocity curves. This effect may introduce significant uncertainties in the mass determination of unseen companions. The line-profile variability is produced almost entirely by the azimuthal component of the velocity perturbations, Δ V\\varphi'. We put forth the hypothesis that the differentially-rotating external layers that develop in non-synchronous binary systems may lead to the generation of magnetic activity near the stellar surface. The possibility of constraining the values of ν near the stellar surface through the use of line-profile variability is also suggested.

  9. The Importance of Continued Satellite Gravity Missions for Understanding Ocean Mass Variability

    NASA Astrophysics Data System (ADS)

    Chambers, Don

    2010-05-01

    Global gravity observations from satellite missions such as GRACE are unique in the way that they observe mass exchanges among the ocean, cryosphere, and land, as well as mass exchanges from one ocean basin to another. No longer does one need to patch together disparate measurements (e.g., sea level, in situ temperature measurements, glacier and ice sheet surface mass balances, unknown land hydrology) to infer changes in the global ocean mass. For the first time, we can directly measure it. We can also observe local fluctuations in the ocean mass caused by changes in wind stress and ocean circulation, not all of which can be modeled accurately. We will review recent results for global ocean mass variability and ocean mass exchange between basins and point out problems with inferring these by other means, such as combinations of altimetry and in situ temperature profilers and from global ocean models. We have only recently been able to appreciate the unique information on low-frequency fluctuations in local and global ocean mass that can be gained from satellite gravity missions. It would be a shame to loose this important new data in the coming years and return to process of inferring ocean mass variability rather than measuring it.

  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. 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 integrative climatic signal in the averaged mass balance records of the selected regions; (ii) to analyse the possible coupling between the mass balance and climatic variables, including the dominant patterns of Northern Hemisphere climate variability; and (iii) to compare the main characteristics of the three regions. Furthermore, (iv) a short discussion is given considering the significant decreasing trend of the cumulative annual mass balances in every region under the detected climatic changes in the second half of the 20th century. Preliminary results suggest that the strongest teleconnection links could be between winter mass balance and winter NAO for the Polar Ural (r=0.46, p<0.05), and between annual mass balance and PDO for Svalbard (r=-0.43, p<0.05). Neither seasonal, nor annual mass balance records showed significant correlation with any of the examined circulation indices for the Caucasus.

  12. A minimal model for reconstructing interannual mass balance variability of glaciers in the European Alps

    NASA Astrophysics Data System (ADS)

    Marzeion, B.; Hofer, M.; Jarosch, A. H.; Kaser, G.; Mölg, T.

    2012-01-01

    We present a minimal model of the glacier surface mass balance. The model relies solely on monthly precipitation and air temperatures as forcing. We first train the model individually for 15 glaciers with existing mass balance measurements. Based on a cross validation, we present a thorough assessment of the model's performance outside of the training period. The cross validation indicates that our model is robust, and our model's performance compares favorably to that from a less parsimonious model based on seasonal sensitivity characteristics. Then, the model is extended for application on glaciers without existing mass balance measurements. We cross validated the model again by withholding the mass balance information from each of the 15 glaciers above during the model training, in order to measure its performance on glaciers not included in the model training. This cross validation indicates that the model retains considerable skill even when applied on glaciers without mass balance measurements. As an exemplary application, the model is then used to reconstruct time series of interannual mass balance variability, covering the past two hundred years, for all glaciers in the European Alps contained in the extended format of the world glacier inventory. Based on this reconstruction, we present a spatially detailed attribution of the glaciers' mass balance variability to temperature and precipitation variability.

  13. 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.

  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. Supersingular mass distributions in gelling systems

    NASA Astrophysics Data System (ADS)

    Lushnikov, A. A.

    2012-11-01

    This paper considers the time evolution of disperse systems in which binary coagulation is so rapid that it leads to formation of gels during a finite but nonzero interval of time. Right before the transition point an algebraic particle mass spectrum forms whose behavior at small particle masses does not permit one to define the total particle mass concentration as ∫0∞gc(g,t)dg, because the integral diverges at low limit. This divergency prevents the formulation of an asymptotic self-similarity spectrum in its traditional form. This difficulty is avoided by introducing the second moment of the particle mass spectrum as a basic scale defining its behavior at the pregelation stage. The equations for the universality mass spectra are formulated. It is shown that these equations correctly reproduce the asymptotic form of the particle mass spectrum for the system with the product kernel. The postcritical behavior in this case is investigated. The time dependencies of the gel mass, the second moment, and particle number concentrations in the postcritical period are found.

  16. 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.

  17. 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.

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

    NASA Astrophysics Data System (ADS)

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

  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. A minimal model for reconstructing interannual mass balance variability of glaciers in the European Alps

    NASA Astrophysics Data System (ADS)

    Marzeion, B.; Hofer, M.; Jarosch, A. H.; Kaser, G.; Mölg, T.

    2011-10-01

    We present a minimal model of the glacier surface mass balance. The model relies solely on monthly precipitation and air temperatures as forcing. We first train the model individually for 15 glaciers with existing mass balance measurements. Based on a cross validation, we present a thorough assessment of the model's performance outside of the training period. The cross validation indicates that our model is robust, and our model's performance compares favorably to that from a less parsimonious model based on seasonal sensitivity characteristics. Then, the model is extended for application on glaciers without existing mass balance measurements, and cross validated using the 15 glaciers above, in order to measure its performance on glaciers not included in the model training. This cross validation indicates that the model retains considerable skill even when applied on glaciers without mass balance measurements. As an exemplary application, the model is then used to reconstruct time series of interannual mass balance variability, covering the past two hundred years, for all glaciers in the European Alps contained in extended format of the world glacier inventory. Based on this reconstruction, we present a spatially detailed attribution of the glaciers' mass balance variability to temperature and precipitation variability.

  1. Accurate masses of very low mass stars. II. The very low mass triple system GL 866

    NASA Astrophysics Data System (ADS)

    Delfosse, X.; Forveille, T.; Udry, S.; Beuzit, J.-L.; Mayor, M.; Perrier, C.

    1999-10-01

    We present very accurate orbital parameters and mass measurements (2.4% accuracy) for the well known very low mass triple system Gl 866. We obtain first orbital elements for the short-period orbit and greatly improve the long period orbit. All three stars have masses close to 0.1 M_sun, and the system thus provides the strongest constraints to date on the mass-luminosity relation close to the brown dwarf limit. Based on observations made at the Observatoire de Haute Provence (CNRS), and at the CFH Telescope, operated by the NRCC, the CNRS and the University of Hawaii. Table 3 is only avaliable electronically with the On-Line publication at http://link.springer.de/link/service/journals/00230/

  2. Mass loss, long-period variables, and the formation of circumnebular shells

    NASA Technical Reports Server (NTRS)

    Kafatos, M.; Michalitsanos, A. G.; Vardya, M. S.

    1977-01-01

    We have found that the rate of mass loss M increases with an increase in the period of pulsation for Mira-type variables. This result suggests that the rate of mass loss is accelerated with time until a maximum value is reached before the ejection of the outer envelope. The matter from the continuous mass loss during the evolution of the star produces supersonic shock waves that sweep up the interstellar gas upon encountering the interstellar medium, so that a shell is formed. This phenomenon may account for the observations of extended regions of emission that surround planetary nebulae.

  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. 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.

  5. Large Archival Mass Memory System Using Optical Diskettes

    NASA Astrophysics Data System (ADS)

    Watkins, J. W.; Boudreaux, N. A.; Otten, T. H.

    1981-06-01

    The transition of digital optical mass storage technologies from the laboratory to an integrated deliverable system is a challenge whose time has come. Harris Corporation has accepted the challenge and will deliver a 1013 bit Archival Mass Memory (AMM) System. AMM provides: variable data ingest rates up to 50 Mbits/sec accommodating sources as diverse as telephone links, computer links, and satellite downlinks; Reed-Solomon error detection and correction (EDAC) coding to preserve better than a 10 -9 bit error rate (BER) for up to 10 years of operation without rerecording; real time optical spot recording of 109 user bits on each 148 X 148 mm diskette; storage and automatic on-line retrieval of data from 1024 diskettes housed in each storage and retrieval unit; less than 15 second access time to any record in the archive; simultaneous data recording and readout; forward file management for rapid user-oriented access down to the byte level; simultaneous access to multiple modular storage and retrieval units; and variable output rates up to 50 Mbits/second direct or interleaved for multiple variable rate users tied to the fiber-optic distribution bus. This paper outlines the system design and performance including the complex electro-optic technologies employed to provide high-speed high-density optical spot recording and readout.

  6. 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.

  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

    2016-04-01

    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

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

    NASA Astrophysics Data System (ADS)

    Vovk, Ievgen; Babić, Ana

    2015-06-01

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

  9. Climate variability and deep water mass characteristics in the Aegean Sea

    NASA Astrophysics Data System (ADS)

    Georgiou, S.; Mantziafou, A.; Sofianos, S.; Gertman, I.; Özsoy, E.; Somot, S.; Vervatis, V.

    2015-01-01

    The main objective of this study is to investigate the variability of the thermohaline characteristics of the deep-water masses in the Aegean Sea and the possible impact of the regional atmospheric forcing variability by analyzing the available oceanographic and atmospheric datasets for the period of 1960-2012. During this period the variability of the deep water characteristics of the Aegean sub-basins is found to be very large as well as the diversity of the deep water characteristics among the sub-basins. The Central Aegean seems to play the key role in the Aegean deep water formation processes. Due to its small size, the Aegean Sea surface responds rapidly to the meteorological changes and/or the variability of the lateral fluxes and this variability propagates in the thermohaline characteristics of the deep water masses of the basin through deep water formation processes. There are many episodes characterized by a tight coupling of the atmosphere and the ocean during the examined period, with the Eastern Mediterranean Transient (EMT) being the most prominent case. We suggest that deep water formation is triggered mostly by the combination of preconditioning during early winter and/or previous winters together with the number of subsequent extreme events during present winter and not only by the total amount of the extreme heat loss winter days.

  10. 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.

  11. 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.

  12. Stronger steerability criterion for more uncertain continuous-variable systems

    NASA Astrophysics Data System (ADS)

    Chowdhury, Priyanka; Pramanik, Tanumoy; Majumdar, A. S.

    2015-10-01

    We derive a fine-grained uncertainty relation for the measurement of two incompatible observables on a single quantum system of continuous variables, and show that continuous-variable systems are more uncertain than discrete-variable systems. Using the derived fine-grained uncertainty relation, we formulate a stronger steering criterion that is able to reveal the steerability of NOON states that has hitherto not been possible using other criteria. We further obtain a monogamy relation for our steering inequality which leads to an, in principle, improved lower bound on the secret key rate of a one-sided device independent quantum key distribution protocol for continuous variables.

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

    NASA Astrophysics Data System (ADS)

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

    2009-03-01

    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 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° C while the heat losses caused by the addition of the VCHP are 1.8 W.

  14. 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.

  15. 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.

    2016-02-01

    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-LTE based spectrum analysis reveals two stars of similar atmospheric chemical composition consistent with the present day cosmic abundance standard defined by Nieva & Przybilla (2012). 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.

  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 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.

  18. 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.

  19. 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).

  20. 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: operation hours, random/nonrandom failures, software/hardware failures, quantity, orbital replaceable units (ORU), date of placement, unit weight, frequency of part, etc. The motivation for creating such a database will be the development of a mass/reliability parametric model to estimate mass required for replacement parts. Once complete, engineers working on future space flight missions will have access a mean time to failures and on parts along with their mass, this will be used to make proper decisions for long duration space flight missions

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

    SciTech Connect

    Kamizasa, Naoya; Terashima, Yuichi; Awaki, Hisamitsu

    2012-05-20

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

  2. Variable neural adaptive robust control: a switched system approach.

    PubMed

    Lian, Jianming; Hu, Jianghai; Żak, Stanislaw H

    2015-05-01

    Variable neural adaptive robust control strategies are proposed for the output tracking control of a class of multiinput multioutput uncertain systems. The controllers incorporate a novel variable-structure radial basis function (RBF) network as the self-organizing approximator for unknown system dynamics. It can determine the network structure online dynamically by adding or removing RBFs according to the tracking performance. The structure variation is systematically considered in the stability analysis of the closed-loop system using a switched system approach with the piecewise quadratic Lyapunov function. The performance of the proposed variable neural adaptive robust controllers is illustrated with simulations. PMID:25881366

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

    We present simultaneous photometric and spectroscopic observations of seven young and highly variable M dwarfs in star forming regions in Orion, conducted in 4 observing nights with FORS2 at ESO/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 hot spots observed in more massive stars. The remaining targets near ɛ Ori, likely to be older, show eclipse-like lightcurves, 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 disk has disappeared and accretion has ceased.

  4. The Properties of Low-Luminosity AGN: Variability, Accretion Rate, Black Hole Mass and Color

    NASA Astrophysics Data System (ADS)

    Oleas, Juan; Podjed, Stephanie; Sarajedini, Vicki

    2016-01-01

    We present the results from a study of ~5000 Broad-Line selected AGN from the Sloan Digital Sky Survey DR7. Galaxy and AGN templates have been fit to the SDSS spectra to isolate the AGN component. The sources have absolute magnitudes in the range -23 < Mi < -18 and lie at redshifts less than z ~ 0.8. A variability analysis reveals that the anti-correlation between luminosity and variability amplitude continues to the faintest AGN in our sample (Gallastegui-Aizpun & Sarajedini 2014), though the underlying cause of the relation is still poorly understood. To address this, we further explore the connection between AGN luminosity and variability through measurement of the Hβ line width to determine black hole mass and accretion rate. We find that AGN with the highest variability amplitudes at a given luminosity appear to have lower accretion rates compared to low amplitude variables. We also investigate correlations with AGN color and accretion rate among these low-luminosity AGN.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Rotation and variability of very low mass stars and brown dwarfs near ɛ Ori

    NASA Astrophysics Data System (ADS)

    Scholz, A.; Eislöffel, J.

    2005-01-01

    We explore the rotation and activity of very low mass (VLM) objects by means of a photometric variability study. Our targets in the vicinity of ɛ Ori belong to the Ori OB1b population in the Orion star-forming complex. In this region we selected 143 VLM stars and brown dwarfs (BDs), whose photometry in RIJHK is consistent with membership of the young population. The variability of these objects was investigated using a densely sampled I-band time series covering four consecutive nights with altogether 129 data points per object. Our targets show three types of variability: Thirty objects, including nine BDs, show significant photometric periods, ranging from 4 h up to 100 h, which we interpret as the rotation periods. Five objects, including two BDs, exhibit variability with high amplitudes up to 1 mag which is at least partly irregular. This behaviour is most likely caused by ongoing accretion and confirms that VLM objects undergo a T Tauri phase similar to solar-mass stars. Finally, one VLM star shows a strong flare event of 0.3 mag amplitude. The rotation periods show dependence on mass, i.e. the average period decreases with decreasing object mass, consistent with previously found mass-period relationships in younger and older clusters. The period distribution of BDs extends down to the breakup period, where centrifugal and gravitational forces are balanced. Combining our BD periods with literature data, we found that the lower period limit for substellar objects lies between 2 h and 4 h, more or less independent of age. Contrary to stars, these fast rotating BDs seem to evolve at constant rotation period from ages of 3 Myr to 1 Gyr, in spite of the contraction process. Thus, they should experience strong rotational braking. Based on observations collected at the European Southern Observatory, Chile, observing run 68.C-0213(A) Table 2 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http:/ /cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/429/1007.

  10. 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.

  11. 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.

  12. Assessing the effect of Ross Sea source water mass variability on bottom waters offshore

    NASA Astrophysics Data System (ADS)

    Wiederwohl, C. L.; Orsi, A. H.; Johnson, G. C.; Purkey, S. G.

    2009-12-01

    The Southern Ocean interacts with the polar atmosphere and cryosphere year-round. The active exchange of heat and freshwater among ocean, atmosphere, and cryosphere over the continental margins facilitates the rapid propagation of ongoing changes in the Antarctic environment. Oceanic boundary currents carry these signals to the abyssal layers of ocean basins farther to the north. The lack of adequate direct long-term time series of measurements at key locations along the current paths has made it difficult for oceanographers to assess fully the magnitude of change in ocean climate. To mitigate this shortcoming, we take advantage of a new volumetric θ-S census of Ross Sea waters to perform sensitivity studies of the variability in dense deep and bottom water production rates and export estimates. Inspection of historical oceanographic data combined with recent hydrographic stations in the Eastern Ross Sea already reveal long-term variability in source water mass properties that affect dense water formation. We estimate plausible temporal variabilities of inflowing water mass properties and their likely roles in changes of bottom water characteristics found further offshore along 150°W and 103°W.

  13. 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.

  14. 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.

  15. 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.

  16. PERFORMANCE OF A VARIABLE RATE CENTER PIVOT SYSTEM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    US farmers have access to equipment for variable-rate application of most inputs, but some potential benefits of precision agriculture may be masked by uniform application of irrigation water. A system developed at the University of Georgia for variable-rate (VR) water application was installed on a...

  17. 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…

  18. 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.

  19. 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.

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

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

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

  1. 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.

  2. The sensitivity of tree growth to air mass variability and the Pacific Decadal Oscillation in coastal Alabama.

    PubMed

    Senkbeil, Jason C; Rodgers, John C; Sheridan, Scott C

    2007-08-01

    This study investigates the relationship between tree growth and air mass type variability, using the spatial synoptic classification (SSC) in a bottomland slash pine forest in coastal Alabama (USA). The use of an air mass approach in dendroclimatology is somewhat unconventional and has not been fully explored. However, we believe that it may be useful because the air mass approach represents a holistic and comprehensive measure of surface conditions. Cores from 36 slash pines (Pinus elliotti) were extracted and ring widths were measured to the nearest 0.01 mm. The cores were then cross-dated and a standardized ring index series was established. Relationships were explored between the index series and several climate variables and teleconnections. The index series showed significant relationships with SSC air mass types and SSC air mass ratios, but insignificant results with teleconnections. Specifically the Dry Tropical air mass type was negatively correlated with tree growth while Moist Moderate was positively correlated. Concomitantly, Dry Tropical : Moist Moderate, Dry Tropical : Moist Tropical, and Dry Moderate : Moist Moderate air mass ratios also showed negative correlations. Positive Pacific Decadal Oscillation (PDO) sea surface temperatures were also associated with significant moisture and air mass variability in the region, although the PDO did not have a significant relationship with tree growth. The significance between SSC air mass variability and tree growth in the humid subtropical climate of coastal Alabama has favorable implications for dendroclimatological research in drier environments where trees are more sensitive to climatic variables. PMID:17333289

  3. A Unified Analysis of Time Variability in Chandra Grating Observations of Low-Mass Stars

    NASA Astrophysics Data System (ADS)

    Posson-Brown, Jennifer; Kashyap, V.; Saar, S.; Drake, J.

    2011-09-01

    We are carrying out a unified study of archival Chandra grating observations of active low-mass coronal stars and present preliminary results here. We include ACIS-S/HETG, ACIS-S/LETG, and HRC-S/LETG observations. Gratings data are optimal for timing analysis since they are free from pile-up and allow for joint spectro-temporal analysis. We discuss techniques for timing analysis of gratings data and explore the distribution of stellar flare energies and the time variability of individual lines fluxes. This work is supported by CXC NASA contract NAS8-39073 and Chandra grant AR0-11001X.

  4. 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

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

    NASA Astrophysics Data System (ADS)

    Ştefan, Sabina; Roman, Iuliana

    2015-06-01

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

  6. The Barents Sea frontal zones and water masses variability (1980-2011)

    NASA Astrophysics Data System (ADS)

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

    2016-01-01

    The polar front separates the warm and saline Atlantic Water entering the southern Barents Sea from the cold and fresh Arctic Water located in the north. These water masses can mix together (mainly in the center of the Barents Sea), be cooled by the atmosphere and receive salt because of brine release; these processes generate dense water in winter, which then cascades into the Arctic Ocean to form the Arctic Intermediate Water. To study the interannual variability and evolution of the frontal zones and the corresponding variations of the water masses, 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 1980-2011 period. The summer data were interpolated on a regular grid. A probability density function 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 identified: the Northern Front is associated with strong salinity gradients and the Southern Front with temperature gradients. Both fronts enclose the denser 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. The frontal zones variability is found by using data from a general circulation model. The link with the atmospheric variability, represented here by the Arctic Oscillation, is not clear. However, model results suggest that such a link could be validated if winter data were taken into account. A strong trend appears: the Atlantic Water (Arctic Water) occupies a larger (smaller) volume of the Barents Sea. This trend amplifies during the last decade and the model study suggests that this could be accompanied by a northwards displacement of the Southern Front in the eastern part of the Barents Sea. The results are less clear for the Northern Front. The observations show that the volume of the Barents Sea Water remains nearly unchanged, which suggests a northwards shift of the Northern Front to compensate for the northward shift of the Southern Front. Lastly, we noticed that the seasonal variability of the position of the front is small.

  7. 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 projectile equipped with both an ITM and canard control mechanisms. Monte Carlo simulations that incorporated realistic uncertainty demonstrated the robust nature of the control system. These dispersion simulations examined the effect of ITM size and incorporation of a variable stability mechanism. It is shown that use of an ITM as a direct control mechanism can reduce circular error probable by nearly half, while coupling ITM control with canard control can reduce required canard area by approximately half as well. Overall, it was determined that direct ITM control generates modest control authority for practical systems. Therefore, it can be used to reduce dispersion error but not eliminate it to levels commensurate with sensor noise. Likewise, the ITM variable stability mechanism provides a limited control authority enhancement to guided projectiles controlled by other means. Thus, while the mechanism may not be useful for guided munitions that exhibit ample control authority, it provides a useful supplement to projectiles requiring slight control authority improvement.

  8. 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.

  9. 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.

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

    NASA Astrophysics Data System (ADS)

    Alexander, P. M.; Tedesco, M.; Schlegel, N.-J.; Luthcke, S. B.; Fettweis, X.; Larour, E.

    2015-11-01

    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. Here, we examine spatiotemporal variations in mass over the GrIS derived from the Gravity Recovery and Climate Experiment (GRACE) satellites for the 2003-2012 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 -179 and -240 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, there are significant differences in the timing of peaks in the annual cycle of mass change. At these scales, model biases, or unaccounted-for processes related to ice dynamics or hydrology may lead to the observed differences. This highlights the need for further evaluation of modelled processes at regional and seasonal scales, and further study of ice sheet processes not accounted for, such as the role of sub-glacial hydrology in variations in glacial flow.

  11. Global Variability of Mesoscale Convective System

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

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

  12. 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

  13. 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…

  14. 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.

  15. Vapor recovery system with variable delay purge

    SciTech Connect

    Yost, J.V.

    1988-05-03

    In a vehicle fuel vapor recovery system of the type in which fuel vapors are selectively drawn from a vapor storage canister through a canister purge valve and purge line by engine manifold vacuum to be burned in the engine, the canister purge valve being activated by vacuum drawn through a control vacuum line from a control vacuum source that is exposed either to manifold vacuum or to atmosphere respectively as an engine throttle is opened or closed, a control means for activating the canister purge valve with a time delay after throttle opening that depends on how long the throttle has been closed before opening, the control means is described comprising, in combination: an air accumulator in communication with the control vacuum line to which air can be sent and from which air can be drawn, and air valve means acting in cooperation with the accumulator to restrict the drawing of air through the control vacuum line when the throttle is first opened.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Interannual variability of water mass properties in the Tunisia-Sicily Channel

    NASA Astrophysics Data System (ADS)

    Ben Ismail, Sana; Schroeder, Katrin; Sammari, Chérif; Gasparini, Gian Pietro; Borghini, Mireno; Aleya, Lotfi

    2014-07-01

    We analysed in situ CTD data collected on 36 joint Tunisian-Italian oceanographic cruises in the Tunisia-Sicily Channel (Cap Bon-Mazara del Vallo section) from 1995 to 2009 in order to identify the water masses in the region and to estimate the interannual variability of their hydrological characteristics. Besides the well-known AW (Atlantic Water) and LIW (Levantine Intermediate Water), other water masses have been identified though their presence is neither as steady nor as stable as the aforementioned ones. The WIW (Western Intermediate Water) flows beneath the AW towards the eastern basin while the IW (Ionian Water), with a highly intermittent character, flows within the subsurface layer towards the western basin. The flow of subsurface water (WIW and IW) is affected by intense mixing which modifies the water masses, tending to make them disappear. Moreover, the same hydrological time series produced interesting results concerning the increase in both temperature and salinity in the Tunisia-Sicily Channel. This trend especially concerns the deeper layers (LIW and tEMDW, i.e. transitional Eastern Mediterranean Deep Water) and we hypothesise that this is a direct response to climatic change occurring in the eastern basin.

  2. 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.

  3. Fractal variability: an emergent property of complex dissipative systems.

    PubMed

    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. PMID:22462984

  4. Mass Transfer and Tidal Dynamics in White Dwarf Binary Systems

    NASA Astrophysics Data System (ADS)

    Gerber, Jeffrey; Fuller, J.

    2014-01-01

    Compact white dwarf (WD) binary systems (with orbital periods ranging from minutes to hours) can produce a variety of interesting astrophysical objects (e.g., type Ia supernovae, AM CVn systems, R Cor Bor stars, sdB stars) upon the onset of mass transfer. These systems are driven toward Roche lobe overflow by the emission of gravitational radiation, but it is not known whether the mass transfer will be stable (forming an Am CVn system) or become unstable (resulting in a merger). We analyze how the combined effects of mass transfer and tidal torques affect the evolution of these systems by creating numerical models with the MESA stellar evolution program. Using new calculations of the tidal torque in rotating WDs, we predict the outcome of mass transfer in these systems as a function of the masses of the WD components. We find that the stability of mass transfer depends primarily on the peak mass transfer rate near the period minimum, which is highly dependent on the WD masses and on the strength of the tidal torques. Except for low WD accretor masses, the tidal torques are insufficient to significantly increase the stability of mass transfer. We find that mass transfer is generally unstable for WD donor masses greater than about 0.25 solar masses, and that the 12 minute system SDSS J0615 will end its inspiral in a WD merger, likely producing an R Cor Bor star.

  5. Stability theorems for multidimensional linear systems with variable parameters

    NASA Technical Reports Server (NTRS)

    Shrivastava, S. K.

    1981-01-01

    A Liapunov-type approach is used to derive two equivalent theorems which govern the stability of coupled linear systems with varying multiple parameters. The theorems generalize some of the existing theorems applicable to systems with constant parameters and the Sonin-Polya theorem applicable to a single-degree-of-freedom system with variable coefficients. As an illustration, the proposed theorems are applied to mechanical systems with varying inertia, stiffness, gyroscopic, and damping terms, and velocity and position-dependent forces.

  6. Viscous boundary value problems for symmetric systems with variable multiplicities

    NASA Astrophysics Data System (ADS)

    Gues, Olivier; Métivier, Guy; Williams, Mark; Zumbrun, Kevin

    Extending investigations of Métivier and Zumbrun in the hyperbolic case, we treat stability of viscous shock and boundary layers for viscous perturbations of multidimensional hyperbolic systems with characteristics of variable multiplicity, specifically the construction of symmetrizers in the low-frequency regime where variable multiplicity plays a role. At the same time, we extend the boundary-layer theory to "real" or partially parabolic viscosities, Neumann or mixed-type parabolic boundary conditions, and systems with nonconservative form, in addition proving a more fundamental version of the Zumbrun-Serre-Rousset theorem, valid for variable multiplicities, characterizing the limiting hyperbolic system and boundary conditions as a nonsingular limit of a reduced viscous system. The new effects of viscosity are seen to be surprisingly subtle; in particular, viscous coupling of crossing hyperbolic modes may induce a destabilizing effect. We illustrate the theory with applications to magnetohydrodynamics.

  7. 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.

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

    NASA Astrophysics Data System (ADS)

    Carton, X.; L'Hegaret, P.

    2011-06-01

    By analysing ARGO float data over the last four years, some aspects of the mesoscale variability of water masses in the Arabian Sea are described. The Red Sea Water outflow is strong in the Southwestern Gulf of Aden, in particular when a cyclonic gyre predominates in this region. Salinities of 36.5 and temperatures of 16 °C are found there between 600 and 1000 m depths. The Red Sea Water is more dilute in the eastern part of the Gulf, and fragments of this water mass can be advected offshore across the gulf or towards its northern coast by the regional gyres. The Red Sea Water outflow is also detected along the northeastern coast of Socotra, and fragments of RSW are found between one and three degrees of latitude north of this island. In the whole Gulf of Aden, the correlation between the deep motions of the floats and the SSH measured by altimetry is strong, at regional scale. The finer scale details of the float trajectories are more often related to the anomalous water masses that they encounter. The Persian Gulf Water (PGW) is found in the float profiles near Ras ash Sharbatat (near 57° E, 18° N), again with 36.5 in salinity and about 18-19 °C in temperature. These observations were achieved in winter when the southwestward monsoon currents can advect PGW along the South Arabian coast. Fragments of PGW are found in the Arabian Sea between 18 and 20° N and 63 and 65° E, showing that this water mass can escape the Gulf of Oman southeastward, in particular during summer.

  9. Observations of the variability of shallow trade wind cumulus cloudiness and mass flux

    NASA Astrophysics Data System (ADS)

    Lamer, K.; Kollias, P.; Nuijens, L.

    2015-06-01

    Two years of ground-based remote sensing observations are used to study the vertical structure of marine cumulus near the island of Barbados, including their cloud fraction and mass flux profile. Daily radar derived cloud fraction profiles peak at different height levels depending on the depth of the cumuli and thus the extent to which they precipitate. Nonprecipitating cumuli have a peak cloud fraction of about 5% near mean cloud base (700 m), whereas precipitating cumuli tend to have a peak of only 2% near cloud base. Nineteen percent of the precipitating cumuli are accompanied by large cloud fractions near the detrainment level of cumulus tops (~1700 m). Day-to-day variations in cloud fraction near cloud base are modest (~3%). Nonprecipitating cumuli have their largest reflectivities near cloud top and an ascending core surrounded by a subsiding shell. Precipitating cumuli with enhanced elevated cloudiness (stratiform outflow) are deeper and contain larger vertical gradients in reflectivity and Doppler velocity than precipitating cumuli without such outflow. Bulk (3 h) statistics reveal that nonprecipitating shallow cumuli are active and organized. They contain on average 79% in-cloud updrafts with 86% of them being organized in large coherent structures contributing to a maximum updraft mass flux of 8-36 gm-2 s-1 just above cloud base. Alternatively, downdrafts contribute insignificantly to the mass flux and show little vertical and temporal variability (0-7 gm-2 s-1). Complementary Raman lidar information suggests that updraft mass flux profile slope is inversely related to environmental relative humidity.

  10. 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.

  11. A VARIABLE FLOW CONTROL SYSTEM FOR SUBSURFACE DRIP IRRIGATION*

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It is important for an irrigation system to have a stable constant pressure to obtain efficient water management for crops. A simple mechanical flow control system with a pressure regulating valve was investigated for subsurface drip irrigation to maintain constant pressure under variable flow condi...

  12. Evaluation of a center pivot variable rate irrigation system

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  13. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

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

  15. 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.

  16. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  18. Hybrid orthosis system with a variable hip coupling mechanism.

    PubMed

    To, C S; Kobetic, R; Triolo, R J

    2006-01-01

    Existing reciprocating gait orthoses, to help restore gait to individuals with paraplegia, have a fixed 1:1 hip flexion/extension coupling ratios (FECR), limiting stride length and gait speed. The purpose of this study was to develop a hip reciprocating mechanism for the hybrid orthosis system that is capable of variable hip FECR. The design of the new variable hip reciprocating mechanism incorporates a hydraulic system which utilizes solenoid valves to control coupling between cylinders linked to each hip joint of the orthosis. A specific set of valves are pulsed to achieve continual variable hip coupling. It was shown that piston velocity was inversely proportional to pulse width and also dependent on pulsing frequency. Internal losses in the hydraulic hip reciprocating mechanism occur primarily in the cylinders. Feedback control will be achieved with a dual layer gait event detector consisting of a fuzzy inference system and a set of supervisory rules. PMID:17946991

  19. Factorial Experimental Designs Elucidate Significant Variables Affecting Data Acquisition on a Quadrupole Orbitrap Mass Spectrometer

    NASA Astrophysics Data System (ADS)

    Randall, Shan M.; Cardasis, Helene L.; Muddiman, David C.

    2013-10-01

    Instrument parameter values for a quadrupole Orbitrap mass spectrometer were optimized for performing global proteomic analyses. Fourteen factors were evaluated for their influence on data-dependent acquisition with an emphasis on both the rate of sequencing and spectral quality by maximizing two individually tested response variables (unique peptides and protein groups). Of the 14 factors, 12 factors were assigned significant contrast values ( P < 0.05) for both response variables. Fundamentally, when optimizing parameters, a balance between spectral quality and duty cycle needs to be reached in order to maximize proteome coverage. This is especially true when using a data-dependent approach for sequencing complex proteomes. For example, maximum ion injection time, automatic gain control settings, and minimum threshold settings for triggering MS/MS isolation and activation all heavily influence ion signal, the number of spectra collected, and spectral quality. To better assess the effect these parameters have on data acquisition, all MS/MS data were parsed according to ion abundance by calculating the percent of the AGC target reached for each MS/MS event and then compared with successful peptide-spectrum matches. This proved to be an effective approach for understanding the effect of ion abundance on successful peptide-spectrum matches and establishing minimum ion abundance thresholds for triggering MS/MS isolation and activation.

  20. 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

  1. Simultaneous U BV RI observations of the cataclysmic variable AE Aquarii: Temperatures and masses of fireballs

    NASA Astrophysics Data System (ADS)

    Zamanov , R. K.; Latev, G. Y.; Stoyanov, K. A.; Boeva, S.; Spassov, B.; Tsvetkova, S. V.

    2012-10-01

    We report simultaneous multicolour observations in 5 bands (U BV RI) of the flickering variability of the cataclysmic variable AE Aqr. Our aim is to estimate the parameters (colours, temperature, size) of the fireballs that produce the optical flares. The observed rise times of the optical flares are in the interval 220-440 s. We estimate the dereddened colours of the fireballs as (U-B)_0˜ 0.8-1.4, (B-V)_0 ˜ 0.03-0.24, and (V-I)_0 ˜ 0.26-0.78. We find for the fireballs temperatures of 10000-25000 K, masses of (7-90)× 1019 g, and sizes of (3-7)× 109 cm (using a distance of d=86 pc). These values refer to the peak of the flares observed in the U BV RI bands. The data are available upon request from the authors. Based on data collected with the telescopes at Bulgarian National Astronomical Observatory Rozhen and Belogradchick Astronomical Observatory.

  2. Adjusting bone mass for differences in projected bone area and other confounding variables: an allometric perspective.

    PubMed

    Nevill, Alan M; Holder, Roger L; Maffulli, Nicola; Cheng, Jack C Y; Leung, Sophie S S F; Lee, Warren T K; Lau, Joseph T F

    2002-04-01

    The traditional method of assessing bone mineral density (BMD; given by bone mineral content [BMC] divided by projected bone area [Ap], BMD = BMC/Ap) has come under strong criticism by various authors. Their criticism being that the projected bone "area" (Ap) will systematically underestimate the skeletal bone "volume" of taller subjects. To reduce the confounding effects of bone size, an alternative ratio has been proposed called bone mineral apparent density [BMAD = BMC/(Ap)3/2]. However, bone size is not the only confounding variable associated with BMC. Others include age, sex, body size, and maturation. To assess the dimensional relationship between BMC and projected bone area, independent of other confounding variables, we proposed and fitted a proportional allometric model to the BMC data of the L2-L4 vertebrae from a previously published study. The projected bone area exponents were greater than unity for both boys (1.43) and girls (1.02), but only the boy's fitted exponent was not different from that predicted by geometric similarity (1.5). Based on these exponents, it is not clear whether bone mass acquisition increases in proportion to the projected bone area (Ap) or an estimate of projected bone volume (Ap)3/2. However, by adopting the proposed methods, the analysis will automatically adjust BMC for differences in projected bone size and other confounding variables for the particular population being studied. Hence, the necessity to speculate as to the theoretical value of the exponent of Ap, although interesting, becomes redundant. PMID:11924573

  3. 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.

  4. 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.

  5. 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

  6. Seasonal variability of black carbon mass in the tropical tropopause layer

    NASA Astrophysics Data System (ADS)

    Spackman, J. R.; Gao, R. S.; Schwarz, J. P.; Watts, L. A.; Fahey, D. W.; Pfister, L.; Bui, T. P.

    2011-05-01

    While most black carbon (BC)-containing particles are removed in the lower troposphere in the tropics, some are lofted to higher altitudes via convection where they may be distributed globally throughout the tropical tropopause layer (TTL). Single-particle measurements of BC aerosol were made from the NASA WB-57F aircraft during both the dry (February 2006) and wet (August 2007) seasons in Central America. BC mass loadings declined sharply with increasing altitude from the ground to 5 km. In the TTL, they were up to six times higher in the wet relative to the dry season. The variability in BC mass was examined using convective-influence back trajectories to determine the source regions. The seasonal differences in the vertical profiles are explained by long-range transport of (1) low-BC air from the southern hemisphere in the dry season and (2) high-BC air from biomass-burning or pollution sources in Africa and Asia advected by the Asian monsoon circulation in the wet season.

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

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

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

  8. 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.

  9. Parsing with logical variables (logic-based programming systems)

    SciTech Connect

    Finin, T.W.; Stone Palmer, M.

    1983-01-01

    Logic based programming systems have enjoyed an increasing popularity in applied AI work in the last few years. One of the contributions to computational linguistics made by the logic programming paradigm has been the definite clause grammar. In comparing DCGS with previous parsing mechanisms such as ATNS, certain clear advantages are seen. The authors feel that the most important of these advantages are due to the use of logical variables with unification as the fundamental operation on them. To illustrate the power of the logical variable, they have implemented an experimental atn system which treats atn registers as logical variables and provides a unification operation over them. They aim to simultaneously encourage the use of the powerful mechanisms available in DCGS and demonstrate that some of these techniques can be captured without reference to a resolution theorem prover. 14 references.

  10. Long Period Variables in the Magellanic Clouds: OGLE + 2 MASS + DENIS

    NASA Astrophysics Data System (ADS)

    Groenewegen, M. A. T.

    2004-10-01

    The 68 000 I-band light curves of variable stars detected by the OGLE survey in the Large and Small Magellanic Clouds (MCs) are fitted by Fourier series, and also correlated with the DENIS and 2MASS all-sky release databases and with lists of spectroscopically confirmed M-, S- and C-stars. Lightcurves and the results of the lightcurve fitting (periods and amplitudes) and DENIS and 2MASS magnitudes are presented for 2277 M-, S-, C-stars in the MCs. The following aspects are discussed: the K-band period-luminosity relations for the spectroscopically confirmed AGB stars, period changes over a timespan of about 17 years in a subset of about 400 LPVs, and candidate obscured AGB stars. The use of a sample of spectroscopically confirmed variables shows specifically that almost all carbon stars are brighter than the tip of the RGB, and occupy sequences A+, B+, C and D. It is shown (for the LMC where there is a sufficient number of spectroscopically identified M-stars) that for sequences A+, B+, C the M-stars are on average fainter than the C-stars, as expected from an evolutionary point of view and previously observed in MC clusters. However, this is not so for sequence ``D'', suggesting that the origin of the so-called Long Secondary Periods is not related to an evolutionary effect. The fraction of objects that has a period in sequence ``D'' is also independent of chemical type. Three stars are identified that have been classified as oxygen-rich in the 1970s and carbon-rich in 1990s. Possibly they underwent a thermal pulse in the last 20 years, and dredged-up enough carbon to switch spectral type. The observations over almost two decades seem to suggest that up to 10% of AGB variables changed pulsation mode over that time span. More robust estimates will come from the ongoing and future (microlensing) photometric surveys. A sample of 570 variable red objects ((J-K) > 2.0 or (I-K) > 4.0) is presented in which most stars are expected to be dust-obscured AGB stars. Estimates are presented for cut-offs in (J-K) which should be applied to minimise dust obscuration in K, and based on this, C- and O-star K-band PL-relations for large amplitude variables in the SMC and LMC are presented. Full Tables \\ref{TAB-A}, \\ref{TAB-B}, \\ref{TAB-C}-\\ref{TAB-F} are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/425/595 Full Figs. \\ref{Fig-LC}, \\ref{Fig-LC-LPV}, \\ref{Fig-LC-IR} and Appendices are only available in electronic form at http://www.edpsciences.org

  11. Variable rate lime application in Louisiana sugarcane production systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Precision agriculture may offer sugarcane growers a management system that decreases costs and maximizes profits, while minimizing any potential negative environmental impact. The utility of variable-rate (VR) lime application in the initial production year (plant cane) of a 3-yr sugarcane crop cyc...

  12. Performance evaluation of a center pivot variable rate irrigation system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Variable Rate Irrigation (VRI) for center pivots offers potential to match specific application rates to non-uniform soil conditions along the length of the lateral. The benefit of such systems is influenced by the areal extent of these variations and the smallest scale to which the irrigation syste...

  13. 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...

  14. Variable-Rate Lime Application for Louisiana Sugarcane Production Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Precision agriculture may offer sugarcane growers a management system that decreases costs and maximizes profits, while minimizing any potential negative environmental impact. Variable rate (VR) application of lime and fertilizers is one area in which significant advantages may be realized. A seri...

  15. 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.

  16. 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

  17. Hydraulic control system for continuously variable V-belt transmission

    SciTech Connect

    Abo, K.; Kumura, H.; Tanaka, Y.; Hirano, H.; Yamamuro, S.

    1986-04-29

    A hydraulic control system is described for a continuously variable V-belt transmission which includes a continuously variable transmission mechanism having a drive pulley, a driven pulley and a V-belt interconnecting the drive and driven pulleys and a change-direction gearing disposed between an engine and the drive pulley to establish a forward drive path or a reverse drive path from the engine to the drive pulley, the change-direction gearing including a forward clutch and a reverse clutch.

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

    PubMed Central

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

    1991-01-01

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

  19. 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 mass extinctions. Put together, these results suggest that environmental factors may have an effect of body size, but it may be the consequence of several environmental factors in conjunction. That is a correlation between body size and an individual environmental factor is hard to determine, but several biotic and abiotic factors may work interdependently to alter body size of crinoids.

  20. Analysis of X-ray spectral variability and black hole mass determination of the NLS1 galaxy Mrk 766

    NASA Astrophysics Data System (ADS)

    Giacchè, S.; Gilli, R.; Titarchuk, L.

    2014-02-01

    We present an XMM-Newton time-resolved spectral analysis of the narrow-line Seyfert 1 galaxy Mrk 766. We analysed eight available observations taken between May 2000 and June 2005 with the EPIC-pn camera in order to investigate the X-ray spectral variability produced by changes in the mass accretion rate. The 0.2 - 10 keV spectra are extracted in time bins longer than 3 ks to have at least 3 × 104 net counts in each bin and then accurately trace the variations of the best-fit parameters of our adopted Comptonization spectral model. We tested a bulk-motion Comptonization (BMC) model which is in general applicable to any physical system powered by accretion onto a compact object, and assumes that soft seed photons are efficiently up-scattered via inverse Compton scattering in a hot and dense electron corona. The Comptonized spectrum has a characteristic power law shape, whose slope was found to increase for large values of the normalization of the seed component, which is proportional to the mass accretion rate ṁ (in Eddington units). Our baseline spectral model also includes a warm absorber lying on the line of sight and radiation reprocessing from the accretion disc or from outflowing matter in proximity to the central compact object. Our study reveals that the normalization-slope correlation, observed in Galactic black hole sources (GBHs), also holds for Mrk 766: variations of the photon index in the range Γ ~ 1.9-2.4 are indeed likely to be related to the variations of ṁ, as observed in X-ray binary systems. We finally applied a scaling technique based on the observed correlation to estimate the BH mass in Mrk 766. This technique is commonly and successfully applied to measure masses of GBHs, and this is the first time it has been applied in detail to estimate the BH mass in an AGN. We obtained a value of MBH = 1.26-0.77+1.00×106 M⊙, which is in very good agreement with that estimated by the reverberation mapping. Appendix A is available in electronic form at http://www.aanda.org

  1. 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.

  2. Time-variable ice mass redistribution and consequences for solid Earth geodesy

    NASA Astrophysics Data System (ADS)

    Ivins, E. R.; Wu, X.; James, T. S.

    2009-05-01

    Long wavelength gravity changes associated with imbalance of the cryosphere and other interannual and secular processes are now being mapped from space using GRACE (Gravity Recovery and Climate Experiment) mission data. The gravity changes are supplemented by constraints that come from bounds on Earth rotation and the drift between the Earth's center-of-mass and center-of-figure. Although the main features of northern hemispheric post-glacial rebound are clearly recovered from GRACE, there is much to be gained from improving the modeled hydrology and ocean tides. In addition, a great deal of uncertainty exists in the forward ice models that are responsible for driving predictions of the present-day signatures arising from viscoelastic relaxation of the Earth's mantle. There is a link between the uncertainties associated with glacial isostasy and the extraction of present-day ice mass changes in Greenland, the Devon Ice Cap and land ice of Canada's Arctic archipelago from space-borne gravity observations. For example, model gravity changes associated with the long-wavelength components of the collapse of the Laurentide forebulge have far greater uncertainty in the northeastern Canadian Arctic archipelago than south of Hudson Bay. This spatially variable uncertainty can now be quantified with increasing confidence, in part, due to constraints that come from tide gauge and GPS measurements. Here we examine and discuss the implications of uncertainties in the timing and size of ice sheet collapse in eastern Canada and we quantify the errors caused in estimating ice loss in Greenland and the Canadian Arctic. The uncertainty is a sensitive function of ice dome size, location, collapse history, lithospheric thickness and mantle viscosity structure.

  3. Mass Assembly of Stellar Systems and their Evolution with the SMA (MASSES)

    NASA Astrophysics Data System (ADS)

    Lee, Katherine I.; Dunham, Michael; Myers, Philip C.; Kristensen, Lars; Goodman, Alyssa A.; Bourke, Tyler L.; Tobin, John J.; Pineda, Jaime E.; Jorgensen, Jes; Arce, Hector G.; Offner, Stella; Vorobyov, Eduard

    2015-01-01

    We present the first results from a legacy project of the SMA: Mass Assembly of Stellar Systems and their Evolution with the SMA (MASSES). The MASSES project surveys a complete sample of all 73 known protostars in the Perseus molecular cloud complex, with both dust continuum and molecular line observations in a variety of dense gas and outflow tracers. The goal of the project is to understand how stars gain their mass through core and disk fragmentation, the formation and evolution of protostellar disks, and outflow-regulated mass accretion. The survey is complementary to a VLA protostar survey with dust continuum (Tobin et al, in prep), which shows a high fraction of multiple protostars. With this larger, unbiased sample and better sensitivity, MASSES will build on results from previous protostar surveys to discern evolutionary trends and to provide a better understanding of the stellar mass assembly process.

  4. The Ionized and Variable Outflow in the Low-Mass X-Ray Binary GX 13+1

    NASA Astrophysics Data System (ADS)

    Allen, Jessamyn; Schulz, Norbert S.; Homan, Jeroen; Chakrabarty, Deepto

    2016-04-01

    We present the analysis of 7 Chandra HETG and 16 simultaneous RXTE PCA observations of GX 13+1, a persistent neutron star low-mass X-ray binary. The observations cover activity between 2002 and 2011. The 0.5-10 keV continuum was consistent with a two component model, either a blackbody plus power law or multicolor disk and blackbody across luminosities of (5-7)x1037 erg sec-1, modified by a neutral absorption column requiring a silicon overabundance. We have identified significantly blue-shifted (voutflow > 500 km sec-1) Kα Fe, Ca, S, and Si hydrogen-like lines in all HETG observations, as well hydrogen-like Ar and Mg lines in the majority of observations. The significant outflow can be modeled as a photoionized plasma with an ionization parameter ≥ 3.5. For the first time we map the occurrence of these wind outflows onto the color-color diagram of GX 13+1 and compare their location with that of the jet outflows in this system. We will further present variable X-ray properties of the wind in GX 13+1 and discuss suggested launching mechanisms as well as how its properties relate to the wind-accretion state in low-mass X-ray binaries.

  5. 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

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

    NASA Astrophysics Data System (ADS)

    Carton, X.; L'Hegaret, P.; Baraille, R.

    2012-03-01

    By analysing ARGO float data over the last four years, a few aspects of the mesoscale variability of water masses in the Arabian Sea are described. The Red Sea Outflow Water (RSOW) is concentrated in the Southwestern Gulf of Aden, in particular when a cyclonic gyre predominates in this region. Salinities of 36.5 and temperatures of 16 °C are found in this area at depths between 600 and 1000 m. RSOW is more dilute in the eastern part of the Gulf, where intense and relatively barotropic gyres mix it with Indian ocean Central Water. RSOW is also detected along the northeastern coast of Socotra, and fragments of RSOW are found between one and three degrees of latitude north of this island. In the whole Gulf of Aden, the correlation between the deep motions of the floats and the sea-level anomaly measured by altimetry is strong, at regional scale. The finer scale details of the float trajectories are not sampled by altimetry and are often related to the anomalous water masses that the floats encounter. The Persian Gulf Water (PGW) is found in the float profiles near Ras ash Sharbatat (near 57° E, 18° N), again with 36.5 in salinity and about 18-19 °C in temperature. These observations were achieved in winter when the southwestward monsoon currents can advect PGW along the South Arabian coast. Fragments of PGW were also observed in the Arabian Sea between 18 and 20° N and 63 and 65° E in summer, showing that this water mass can escape the Gulf of Oman southeastward, during that season. Kinetic energy distributions of floats with respect to distance or angle share common features between the two regions (Gulf of Aden and Arabian Sea), in particular peaks at 30, 50 and 150 km scales and along the axis of monsoon currents. Hydrological measurements by floats are also influenced by the seasonal variations of PGW and RSOW in these regions.

  7. 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{sub L}=0.71) was compared to that obtained from the UD-DBT (A{sub L}=0.78). The authors found no statistically significant difference between the two (p-value=0.22), although all the observers performed better for UD-DBT.

  8. 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.

  9. Mass balance and exergy analysis of a fast pyrolysis system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mass balance closure and exergetic efficiency is evaluated for a bench scale fast pyrolysis system. The USDA Agricultural Research Service (ARS) has developed this system for processing energy crops and agricultural residues for bio-oil (pyrolysis oil or pyrolysis liquids) production. Mass balance c...

  10. 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.

  11. Variability of height, weight, and body mass index in a Swiss armed forces 2005 census.

    PubMed

    Rühli, Frank; Henneberg, Maciej; Woitek, Ulrich

    2008-12-01

    The influence of the environment and genetics on individual biological characteristics, such as body mass and stature is well known. Many studies of these relationships have been based on conscript data. These studies often suffer from the fact that their data cover only a part of the population. Characterized by prosperity, democratic stability and enormous micro-regional cultural diversity, Switzerland is in the unique situation of offering data covering more than 80% of annual male birth cohorts. The aim of this study is to assess the impact of socioeconomic success, cultural differences, month of birth, and altitude (among other factors) on individual anthropometric characteristics of conscripts (N approximately 28,000) in the 2005 census. Our result highlights in such a large male sample the relationship between economic environment, regional cultural diversity, climate, and other factors, such as individual month of birth on stature and weight. Socioeconomic status, culture (as reflected by mother tongue), and month of birth were found to have significant effects on height and weight, while altitude did not show such effects. In general, weight is more affected by all these variables than height. Taking weight-dependent mortality and morbidity into account, it is of foremost public interest to know more about paired effects of living conditions on stature and weight in a highly developed society. PMID:18668685

  12. 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.

  13. 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.

  14. 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.

  15. Detection of bound entanglement in continuous-variable systems

    SciTech Connect

    Zhang Chengjie; Nha, Hyunchul; Zhang Yongsheng; Guo Guangcan

    2010-09-15

    We present several entanglement conditions in order to detect bound entangled states in continuous-variable systems. Specifically, Werner and Wolf [Phys. Rev. Lett. 86, 3658 (2001)] and Horodecki and Lewenstein [Phys. Rev. Lett. 85, 2657 (2000)] have proposed examples of a bound entangled Gaussian state and a bound entangled non-Gaussian state, respectively, of which entanglement can be detected by using our entanglement conditions.

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

    PubMed

    Adesso, Gerardo; Serafini, Alessio; Illuminati, Fabrizio

    2004-11-26

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

  17. 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.

  18. Neutral losses: a type of important variables in prediction of branching degree for acyclic alkenes from mass spectra.

    PubMed

    Zhang, Liangxiao; Fan, Wei; Cao, Dongsheng; Zeng, Maomao; Xiao, Hongbin; Liang, Yizeng

    2012-03-30

    Neutral losses are a type of important variables in mass spectral interpretation. Since it is hard to calculate or extract neutral losses from mass spectra, they are usually discarded. In this study, dissimilarity analysis was employed to extract mass spectral characteristics for predicting branching degree of acyclic alkenes. The relationships between branching degree and neutral loss were constructed under direction of experimental observation and mass spectral fragmentations. A branching degree predictor of acyclic alkenes was subsequently built based on the above relationships. After tested by the experimental data in previous studies, the predictor could correctly provide the branching degree from abundant ions of mass spectra. More importantly, this predictor was able to point out which acyclic alkenes could be predicted correctly or not. PMID:22365115

  19. Wearable depression monitoring system with heart-rate variability.

    PubMed

    Roh, Taehwan; Hong, Sunjoo; Yoo, Hoi-Jun

    2014-01-01

    A wearable depression monitoring system is proposed with an application-specific system-on-chip (SoC) solution. The SoC is designed to accelerate the filtering and feature extraction of heart-rate variability (HRV) from the electrocardiogram (ECG). Thanks to the SoC solution and planar-fashionable circuit board (P-FCB), the monitoring system becomes a low-power wearable system. Its dimension is 14cm × 7cm with 5mm thickness covering the chest band for convenient usage. In addition, with 3.7V 500mAh battery, its lifetime is at least 10 hours. For user's convenience, the system is interfacing to smart phones through Bluetooth communication. With the features of the HRV and Beck depression inventory (BDI), the smart phone application trains and classifies the user's depression scale with 71% of accuracy. PMID:25570021

  20. Spatio-Temporal Variability of the NW African Upwelling System

    NASA Astrophysics Data System (ADS)

    Benítez-Barrios, V. M.; Hernández, F.; Bourdallé-Badie, R.; Pelegrí, J. L.; Hernández-Guerra, A.

    2009-04-01

    The relation of upwelling areas with climate variability is an important issue as these areas, where relatively cold and nutrient-rich waters reach the sea surface, both trap heat excess and become increased biological and physical carbon pumps. Here, we investigate the spatio-temporal evolution of the northwest African Upwelling System, with emphasis on intraseasonal and interannual scales, during the period 2002-2006 using the global high-resolution ocean general circulation model ORCA12-LIM. First, validation of the model is performed by comparison with CTD data collected during CORICA cruise, indicating good agreement between observations and model output. Second, a new criterion, based on the thermal gradient in the normal-to-shore direction, is proposed to determine the upwelled-waters extension. Application of the criterion to the time series of monthly-averaged modelled surface temperatures adequately reproduces the upwelling seasonal cycle as a function of latitude, and shows the presence of interannual variability. The modelled 3D temperature field is combined with the extension of upwelled waters to estimate the amount and variability of upwelling waters. Finally, the response of upwelling to different patterns of wind variability is examined.

  1. On the relationship between black hole mass and X-ray variability amplitude in the low-mass regime of active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Pan, H.; Yuan, W.; Zhou, X.-L.; Dong, X.; Liu, B.

    2016-02-01

    Recent studies of active galactic nuclei (AGN) found a statistical inverse scaling between the X-ray normalized excess variance σrms 2 (variability amplitude) and the black hole mass spanning over M BH = 106 - 109 M ⊙. We present a study of this relation by including AGN with M BH = 105 - 106 M ⊙. It is found that the relation is no longer a simple extrapolation of the known inverse proportion, but starts to flatten around 106 M ⊙. This behavior can be understood by the shape of the power spectrum density of AGN and its dependence on the black hole mass.

  2. Equations of motion and two-equation turbulence model for plane or axisymmetric turbulent flows in body-oriented orthogonal curvilinear coordinates and mass-averaged dependent variables

    NASA Technical Reports Server (NTRS)

    Sislian, J. P.

    1978-01-01

    The full Navier-Stokes time-dependent, compressible, turbulent, mean-flow equations in mass-averaged variables for plane or axisymmetric flow are presented. The equations are derived in a body-oriented, orthogonal, curvilinear coordinate system. Turbulence is modelled by a system of two equations for mass-averaged turbulent kinetic energy and dissipation rate proposed. These equations are rederived and some new features are discussed. A system of second order boundary layer equations is then derived which includes the effects of longitudinal curvature and the normal pressure gradient. The Wilcox and Chambers approach is used in considering effects of streamline curvature on turbulence phenomena in turbulent boundary layer type flows. Their two-equation turbulence model with curvature terms are rederived for the cases considered in the present report. The derived system equations serves as a basis for an investigation of problems where streamline curvature is of the order of the characteristic length in the longitudinal direction.

  3. 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 interannual variability of PV systems will provide a starting point for variability considerations in future PV system designs and investigations. however this type of data is not available when estimating system output during future time frames.

  4. 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.

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

    PubMed Central

    Kumar, D.; Jaiswal, R. K.

    2005-01-01

    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. PMID:24049504

  6. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  8. Compressive Mass Analysis on Quadrupole Ion Trap Systems

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

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

  9. 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.

  10. 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.

  11. Variable structure control of nonlinear systems through simplified uncertain models

    NASA Technical Reports Server (NTRS)

    Sira-Ramirez, Hebertt

    1986-01-01

    A variable structure control approach is presented for the robust stabilization of feedback equivalent nonlinear systems whose proposed model lies in the same structural orbit of a linear system in Brunovsky's canonical form. An attempt to linearize exactly the nonlinear plant on the basis of the feedback control law derived for the available model results in a nonlinearly perturbed canonical system for the expanded class of possible equivalent control functions. Conservatism tends to grow as modeling errors become larger. In order to preserve the internal controllability structure of the plant, it is proposed that model simplification be carried out on the open-loop-transformed system. As an example, a controller is developed for a single link manipulator with an elastic joint.

  12. 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.

  13. 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.

  14. 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.

  15. Mass properties measurement system: Dynamics and statics measurements

    NASA Technical Reports Server (NTRS)

    Doty, Keith L.

    1993-01-01

    This report presents and interprets experimental data obtained from the Mass Properties Measurement System (MPMS). Statics measurements yield the center-of-gravity of an unknown mass and dynamics measurements yield its inertia matrix. Observations of the MPMS performance has lead us to specific design criteria and an understanding of MPMS limitations.

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

    EPA Science Inventory

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

  17. Luminous Blue Variables, Cool Hypergiants, and Supernova Impostors: The Role of Episodic Mass Loss

    NASA Astrophysics Data System (ADS)

    Mehner, A.; de Wit, W. J.; Baade, D.; Boffin, H. M. J.; Davidson, K.; Groh, J.; Humphreys, R. M.; Martayan, C.; Oudmaijer, R. D.; Rivinius, T.; Selman, F.; Steffen, W.

    2015-12-01

    The role of mass loss, especially episodic mass loss, in evolved massive stars is one of the outstanding questions in stellar evolution theory. IFU observations can provide superb information on the recent mass-loss history and the evolutionary stages. With VLT MUSE we have observed a representative sample of massive stars from different evolved stellar classes that underwent episodic mass loss, which gave rise to extended nebulae. The structural inhomogeneities and associated velocity differences in the nebulae are tracers of the mass-loss history. The simultaneous observation of all lines at each position in the nebulae provides very accurate line ratios for physical diagnostics.

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

    NASA Astrophysics Data System (ADS)

    Johnson, Z. I.; Hunt, D.

    2013-12-01

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

  19. 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

  20. 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.

  1. 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.

  2. Small system for tritium accelerator mass spectrometry

    SciTech Connect

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

    1991-12-31

    This invention is comprised of an apparatus for ionizing and accelerating a sample containing isotopes of hydrogen and detecting the ratios of hydrogen isotopes contained in the sample. An ion source generates a substantially linear ion beam including ions of tritium from the sample. A radiofrequency 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.

  3. Earth System Science Education Centered on Natural Climate Variability

    NASA Astrophysics Data System (ADS)

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

    2009-12-01

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

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

    NASA Astrophysics Data System (ADS)

    Cao, Dayong

    2010-10-01

    The solar system is mass-energy center, and the wave (space-time) and planet are around. Sun absorb the matter (mass-energy) and radiate the light (space-time). It's space-time has a space time structure. It has a positive curvature and a sphericalstructure. The dark hole system is the space-time center, and the dark mass-energy and dark planet (dark comet) are around. Dark hole absorb the light (space-time), and radiate the dark mass-energy (mass-energy). The dark mass-energy main make up of the negative proton and the negative neutron who can take negative density and negative pressure. The dark mass-energy has a dark mass-energy structure. It is a negative curvature and a inverse sphericalstructure. The general relativity equation, Rik-12gikR=-κTik. The left of the equation is the metric tensor of the space-time structure; the right of the equation is the energy-momentum tensor. The dark hole has the below equation, R'i'k'-12g'i'k'R'=-κ'T'i'k'. The left of the equation is the metric tensor of the dark mass-energy structure; the right of the equation is the dark space-time (field) tensor. (Rik-12gikR)+(R'i'k'-12g'i'k'R')=-(κTik+κ'T'i'k')=0. The above equation show that the cosmological model is a balance system. The star system and the dark hole system are the uniform distribution. There is the transmutation and the interaction between the dark hole system and star system.

  5. 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.

  6. Upper air relaxation in regional climate model improves resolved interannual variability of the surface mass balance of Antarctica

    NASA Astrophysics Data System (ADS)

    van de Berg, Willem Jan; Medley, Brooke; van Meijgaard, Erik

    2015-04-01

    The surface mass balance (SMB) determines the variability of the mass balance of the Antarctic Ice sheet on sub-decadal timescales. Since continent-wide SMB cannot be measured, it must be modeled and regional climate models (RCMs) generally outperform global reanalyses in the representation of total mass flux and the spatial distribution of SMB. However, if RCMs are only forced with reanalysis on their lateral boundaries, the representation of the interannual variability of SMB deteriorates significantly. In this study we show how to improve the resolved interannual variability in RCM modeled SMB. For this purpose we use annual SMB observations in the Thwaites drainage basin in Antarctica derived from airborne radar reflections and the RCM RACMO2. RACMO2, driven by ERA-Interim, better represents the mean spatial SMB pattern in this basin than ERA-Interim. However, without relaxation in the interior, RACMO2 poorly resolves the observed interannual SMB variability. If we gently relax the temperature and wind field in the upper atmosphere in RACMO2 to ERA-Interim, RACMO2 gets the best of both. Upper air relaxation little changes the mean SMB and spatial pattern compared to the original RACMO2 output, but allows RACMO2 to resolve the observed interannual SMB as good as ERA-Interim.

  7. 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.

  8. MASSIS: a mass spectrum simulation system 1. Principle and method.

    PubMed

    Chen, HaiFeng; Fan, BoTao; Xia, HaiRong; Petitjean, Michael; Yuan, ShenGang; Panaye, Annick; Doucet, Jean-Pierre

    2003-01-01

    A mass spectrum simulation system was developed. The simulated spectrum for a given target structure is computed based on the cleavage knowledge and statistical rules established and stocked in pivot databases: cleavage rule knowledge, function groups, small fragments and fragment-intensity relationships. These databases were constructed from correlation charts and statistical analysis of large population of organic mass spectra using data mining techniques. Since 1980, several systems were proposed for mass spectrum simulation, but in present there is no any commercial software available. This shows the complexity and difficulties in the development of a such system. The reported mass spectral simulation system in this paper could be the first general software for organic chemistry use PMID:12939495

  9. Recent Progress in Exoplanet System Component Masses and Architecture

    NASA Astrophysics Data System (ADS)

    Benedict, G. Fritz; McArthur, B. E.; Bean, J. L.

    2009-09-01

    Observing exoplanet host stars, we combine astrometry acquired with one of the Fine Guidance Sensors on Hubble Space Telescope with radial velocities acquired with the University of Texas Hobby-Eberly Telescope (and other previously published velocities) in aid of two goals. First, we wish to establish the identity of a companion (Jovian planet, brown dwarf, or star) by measuring its mass. This we find by establishing the size of the perturbation. That size, when informed by the mass of the host star and the distance to the system, provides component mass. Second, for some systems we will be able to measure the inclination of two components to establish the architecture of the exoplanetary system. Examples will include a newly measured mass for HD 145675 b = 14 Her b, and a progress report on the mutual inclination of the 'b' and 'c' components of the upsilon And system.

  10. 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).

  11. 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.

  12. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

  14. Building a mass storage system for physics applications

    SciTech Connect

    Holmes, H.; Loken, S.

    1991-03-01

    The IEEE Mass Storage Reference Model and forthcoming standards based on it provide a standardized architecture to facilitate designing and building mass storage systems, and standard interfaces so that hardware and software from different vendors can interoperate in providing mass storage capabilities. A key concept of this architecture is the separation of control and data flows. This separation allows a smaller machine to provide control functions, while the data can flow directly between high-performance channels. Another key concept is the layering of the file system and the storage functions. This layering allows the designers of the mass storage system to focus on storage functions, which can support a variety of file systems, such as the Network File System, the Andrew File System, and others. The mass storage system provides location-independent file naming, essential if files are to be migrated to different storage devices without requiring changes in application programs. Physics data analysis applications are particularly challenging for mass storage systems because they stream vast amounts of data through analysis applications. Special mechanisms are required, to handle the high data rates and to avoid upsetting the caching mechanisms commonly used for smaller, repetitive-use files. High data rates are facilitated by direct channel connections, where, for example, a dual-ported drive will be positioned by the mass storage controller on one channel, then the data will flow on a second channel directly into the user machine, or directly to a high capacity network, greatly reducing the I/O capacity required in the mass storage control computer. Intelligent storage allocation can be used to bypass the cache devices entirely when large files are being moved.

  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 removal of the dependency of or results from near-surface temperature trends. We describe the results of our analysis concerning not only the southwest region but we also focus on the northeast area, where we find also statistically significant correlation between ILWC and open water fraction but later in the summer (e.g. September). We lastly discuss the potential sources of the differences between the results over the west and east regions and suggest a plan for future studies. To our knowledge, this is the first study aiming at combining observations and surface energy balance quantities to improve our understanding of the impact of sea ice loss on surface processes over the Greenland ice sheet.

  16. 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.

  17. Entanglement criteria and nonlocality for multimode continuous-variable systems

    NASA Astrophysics Data System (ADS)

    Sun, Qingqing; Nha, Hyunchul; Zubairy, M. Suhail

    2009-08-01

    We demonstrate how to efficiently derive a broad class of inequalities for entanglement detection in multimode continuous variable systems. The separability conditions are established from partial transposition (PT) in combination with several distinct necessary conditions for a quantum physical state, which include previously established inequalities as special cases. Remarkably, our method enables us to support Peres’ conjecture to its full generality within the framework of Cavalcanti-Foster-Reid-Drummond multipartite Bell inequality [Phys. Rev. Lett. 99, 210405 (2007)] that the nonlocality necessarily implies negative PT entangled states.

  18. Exoplanetary System Dynamics: Planetary Multiplicity and Mass Effects

    NASA Astrophysics Data System (ADS)

    Isoe, Mari; Kokubo, Eiichiro; Turner, Edwin

    2015-12-01

    Recently numerous systems consisting of multiple exoplanets have been discovered. Using a dataset of 375 systems (500 planets) discovered by the radial velocity method and 365 systems (899 planets) containing planet candidates found by the Kepler Mission, we investigate the dependence of the dynamical structure of planetary systems on their multiplicity and the masses of the member planets. We classify the planetary system by three parameters: planetary multiplicity, planetary mass, and the evolutionary stage of the central star. We normalize planetary masses by the mass of the central star and divide the planets into small and large categories by a cut at $10^{-4}$. The central star is classified into main-sequence or giant according to its evolutionary stage. We focus on the angular momentum deficit (AMD) of the systems and the orbital separation between adjacent planets normalized by their Hill radii. We find that in all categories the system AMD decreases with increasing multiplicity. This suggests that in order for multiple systems to be stable, each planet's orbit must be relatively circular. In addition, we find that the distribution of orbital eccentricities of the massive planets and low-mass planets differs. In particular, only high-mass planets have eccentricities larger than 0.4. In the low-mass systems around main sequence stars, we find that the orbital separation decreases with increasing multiplicity. In addition, the orbital separation around main-sequence stars is wider than that around giants. Furthermore, the minimum orbital separation is about 6.4 for non-resonant pairs. This paper presents the statistical properties of the dynamical structure of multiple planetary systems and discusses their formation.

  19. Satellite-based global-ocean mass balance estimates of interannual variability and emerging trends in continental freshwater discharge

    PubMed Central

    Syed, Tajdarul H.; Famiglietti, James S.; Chambers, Don P.; Willis, Josh K.; Hilburn, Kyle

    2010-01-01

    Freshwater discharge from the continents is a key component of Earth’s water cycle that sustains human life and ecosystem health. Surprisingly, owing to a number of socioeconomic and political obstacles, a comprehensive global river discharge observing system does not yet exist. Here we use 13 years (1994–2006) of satellite precipitation, evaporation, and sea level data in an ocean mass balance to estimate freshwater discharge into the global ocean. Results indicate that global freshwater discharge averaged 36,055 km3/y for the study period while exhibiting significant interannual variability driven primarily by El Niño Southern Oscillation cycles. The method described here can ultimately be used to estimate long-term global discharge trends as the records of sea level rise and ocean temperature lengthen. For the relatively short 13-year period studied here, global discharge increased by 540 km3/y2, which was largely attributed to an increase of global-ocean evaporation (768 km3/y2). Sustained growth of these flux rates into long-term trends would provide evidence for increasing intensity of the hydrologic cycle. PMID:20921364

  20. 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…

  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. Exploring The Mass-Loss History and The Dust Content in Circumstellar Nebulae Around Luminous Blue Variable Stars

    NASA Astrophysics Data System (ADS)

    Agliozzo, C.

    2015-12-01

    The physical mechanism responsible for high mass-loss in luminous blue variable stars (LBVs) is still poorly understood. The possibility that it is independent of metallicity is of paramount importance to LBVs in the metal-poor Universe. Our approach to investigate this possibility is to study LBVs in different environments and to use multiwavelength observations to resolve their nebulae. These contain the fingerprints of their mass-loss, as shown here by the galactic example G79.29+0.46. I also present our pilot study of objects in the Magellanic Clouds (MCs), where a paucity of data existed so far.

  3. Stability of control systems with variable time-delay

    NASA Astrophysics Data System (ADS)

    Tracht, Rudolf; Thorausch, Marc

    2003-09-01

    In modern automated systems decentralized concepts are used. Information is communicated via networks as for instance fieldbus systems or industrial ethernet. Since often many users access to the bus, communication time is varying. In most cases this is not critical but for some aplications stability problems are introduced by the varying time-delay. Such applications can be modeled by control loops with a time varying delay block. Different methods were proposed in the last two years for analyzing control systems of this type. Usually state space models are investigated and linear matrix inequalities (LMI) must be solved. The stability region depends not only on the value of the delay time but also on the time-derivative of the variable delay-time. In the paper a new approach for analyzing stability is presented: The control system with delay is considered in the frequency domain. A stability criterion for systems with periodic varying time-delay is derived. By using a suitable transformation more general delay systems can be investigated. The method is illustrated by an example and simulation studies.

  4. 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.

  5. The mass, energy, space and time system theory-MEST

    NASA Astrophysics Data System (ADS)

    Cao, Dayong

    2008-10-01

    Things have their own system of mass, energy, space and time of themself. (The MEST for short thereinafter). Mass is density, energy is force, time is frequency, spac is amplitude square. There are the transmutation between space-time and mass-energy. When they get a balance, they get the inertia and eigenvalue system. The quality of microsubstance mainly is quantum space-time; The nature of the macrosubstance is mainly mass-energy. In wave-particle duality, the quality of wave mainly is quantum space-time; The nature of the particle is mainly mass-energy. New mass-energy wave equation, space-time particle equation are being put forward. With anode dark current of hole and mass wave, give a new explain to the photoelectric effect experiment; and get new mass-energy equation which equal the mass-energy relation of Einstein and Electrodynamics. And the new photoelectric conversion equation are being put forward. Consequently, it is discovered the transmutation between space-time and mass-energy. New atom and nuclear model And New speed of light theory are being put forward. There are different mass of electrons of atom. And explain the probability of wave. Deduce the new uncertainty principle, uncertainty and probability can not be divided. MEST can unites both orbit equations of nine planes and orbit equations of electrons of H and He . MEST can unites both wave equations of nine planes and particle equations of sun. We can change the orbit of asteroid who will impacted near our earth.

  6. 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

  7. 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.

  8. Evaluation of probabilistic prediction systems for a scalar variable

    NASA Astrophysics Data System (ADS)

    Candille, G.; Talagrand, O.

    2005-07-01

    A systematic study is performed of a number of scores that can be used for objective validation of probabilistic prediction of scalar variables: Rank Histograms, Discrete and Continuous Ranked Probability Scores (DRPS and CRPS, respectively). The reliability-resolution-uncertainty decomposition, defined by Murphy for the DRPS, and extended here to the CRPS, is studied in detail. The decomposition is applied to the results of the Ensemble Prediction Systems of the European Centre for Medium-range Weather Forecasts and the National Centers for Environmental Prediction. Comparison is made with the decomposition of the CRPS defined by Hersbach. The possibility of determining an accurate reliability-resolution decomposition of the RPSs is severely limited by the unavoidably (relatively) small number of available realizations of the prediction system. The Hersbach decomposition may be an appropriate compromise between the competing needs for accuracy and practical computability.

  9. An adaptive OFDM system with variable guard interval

    NASA Astrophysics Data System (ADS)

    Lai, Lifeng; Zhang, Zhaoyang; Yu, Guanding; Huang, Aiping; Qiu, Peiliang

    2004-04-01

    Symbol guard interval is almost indispensable to deal with ISI caused by channel delay spreading in wireless OFDM transmission systems. However, the length of guard interval is usually fixed in conventional OFDM system, which decreases the power and spectrum efficiency considerably, especially in a mobile environment. To solve this problem, a novel conceptual adaptive OFDM system with variable guard interval (AOFDM-VGI) is proposed in this paper. This system first utilizes the preamble and pilot sub-carriers of each OFDM packet burst to estimate the channel RMS delay spread, and then the result is fed into the guard interval controller. Then, the controller uses a criterion to calculate the guard interval and control the OFDM transmitter. For a typical simulation model as illustrated in this paper, this system can transmit a data rate 11.5 Mb/s higher and consume a power 0.65 dB less than the conventional non-adaptive counterpart without sacrificing the BER performance.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  11. Variable Doppler shifts of the thermal wind absorption lines in low-mass X-ray binaries

    NASA Astrophysics Data System (ADS)

    Madej, O. K.; Jonker, P. G.; Díaz Trigo, M.; Miškovičová, I.

    2014-02-01

    In this paper, we address the general applicability of the method pioneered by Zhang, Liao & Yao in which the motion of the compact object can be tracked using wind X-ray absorption lines. We present the velocity measurements of the thermal wind lines observed in the X-ray spectrum of a few low-mass X-ray binaries: GX 13+1, H 1743-322, GRO J1655-40 and GRS 1915+105. We find that the variability in the velocity of the wind lines in about all of the sources is larger than conceivable radial velocity variations of the compact object. GX 13+1 provides a potential exception, although it would require the red giant star to be massive with a mass of ≈5-6 M⊙. We conclude that the variability of the source luminosity occurring on a time-scale of days/months can affect the outflow properties making it difficult to track the orbital motion of the compact object using current observations. Given the intrinsic variability of the outflows we suggest that low-mass X-ray binaries showing stable coronae instead of an outflow (e.g. 4U 1254-69, MXB 1659-29, 4U 1624-49) could be more suitable targets for tracking the orbital motion of the compact object.

  12. Galactic model parameters of cataclysmic variables: Results from a new absolute magnitude calibration with 2MASS and WISE

    NASA Astrophysics Data System (ADS)

    Özdönmez, A.; Ak, T.; Bilir, S.

    2015-01-01

    In order to determine the spatial distribution, Galactic model parameters and luminosity function of cataclysmic variables (CVs), a J-band magnitude limited sample of 263 CVs has been established using a newly constructed period-luminosity-colours (PLCs) relation which includes J,Ks and W1-band magnitudes in 2MASS and WISE photometries, and the orbital periods of the systems. This CV sample is assumed to be homogeneous regarding to distances as the new PLCs relation is calibrated with new or re-measured trigonometric parallaxes. Our analysis shows that the scaleheight of CVs is increasing towards shorter periods, although selection effects for the periods shorter than 2.25 h dramatically decrease the scaleheight: the scaleheight of the systems increases from 192 pc to 326 pc as the orbital period decreases from 12 to 2.25 h. The z-distribution of all CVs in the sample is well fitted by an exponential function with a scaleheight of 213-10+11 pc. However, we suggest that the scaleheight of CVs in the Solar vicinity should be ∼300 pc and that the scaleheights derived using the sech2 function should be also considered in the population synthesis models. The space density of CVs in the Solar vicinity is found 5.58(1.35)×10-6 pc-3 which is in the range of previously derived space densities and not in agreement with the predictions of the population models. The analysis based on the comparisons of the luminosity function of white dwarfs with the luminosity function of CVs in this study show that the best fits are obtained by dividing the luminosity functions of white dwarfs by a factor of 350-450.

  13. Gravitational lensing by a smoothly variable three-dimensional mass distribution

    NASA Technical Reports Server (NTRS)

    Lee, Man Hoi; Paczynski, Bohdan

    1990-01-01

    A smooth three-dimensional mass distribution is approximated by a model with multiple thin screens, with surface mass density varying smoothly on each screen. It is found that 16 screens are sufficient for a good approximation of the three-dimensional distribution of matter. It is also found that in this multiscreen model the distribution of amplifications of single images is dominated by the convergence due to matter within the beam. The shear caused by matter outside the beam has no significant effect. This finding considerably simplifies the modeling of lensing by a smooth three-dimensional mass distribution by effectively reducing the problem to one dimension, as it is sufficient to know the mass distribution along a straight light ray.

  14. 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.

  15. 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.

  16. 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.

  17. Arctic mass, freshwater and heat fluxes: methods and modelled seasonal variability.

    PubMed

    Bacon, Sheldon; Aksenov, Yevgeny; Fawcett, Stephen; Madec, Gurvan

    2015-10-13

    Considering the Arctic Ocean (including sea ice) as a defined volume, we develop equations describing the time-varying fluxes of mass, heat and freshwater (FW) into, and storage of those quantities within, that volume. The seasonal cycles of fluxes and storage of mass, heat and FW are quantified and illustrated using output from a numerical model. The meanings of 'reference values' and FW fluxes are discussed, and the potential for error through the use of arbitrary reference values is examined. PMID:26347537

  18. 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

  19. 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)

  20. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

    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 final state particles fully democratically and consider the sorted set of the invariant masses of all 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.

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

    PubMed Central

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

    1983-01-01

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

  3. Design and Manufacturing of Extremely Low Mass Flight Systems

    NASA Technical Reports Server (NTRS)

    Johnson, Michael R.

    2002-01-01

    Extremely small flight systems pose some unusual design and manufacturing challenges. The small size of the components that make up the system generally must be built with extremely tight tolerances to maintain the functionality of the assembled item. Additionally, the total mass of the system is extremely sensitive to what would be considered small perturbations in a larger flight system. The MUSES C mission, designed, built, and operated by Japan, has a small rover provided by NASA that falls into this small flight system category. This NASA-provided rover is used as a case study of an extremely small flight system design. The issues that were encountered with the rover portion of the MUSES C program are discussed and conclusions about the recommended mass margins at different stages of a small flight system project are presented.

  4. 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.

  5. 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.

  6. Crustal uplift due to ice mass variability on Upernavik Isstrøm, west Greenland

    NASA Astrophysics Data System (ADS)

    Nielsen, Karina; Khan, Shfaqat Abbas; Korsgaard, Niels J.; Kjær, Kurt H.; Wahr, John; Bevis, Michael; Stearns, Leigh A.; Timm, Lars H.

    2012-11-01

    We estimate the mass loss rate of Upernavik Isstrøm (UI) using surface elevation changes between a SPOT 5 Digital Elevation Model (DEM) from 2008 and NASA's Airborne Topographic Mapper (ATM) data from 2010. To assess the validity of our mass loss estimate, we analyze GPS data between 2007 and 2011 from two continuous receivers, UPVK and SRMP which are established on bedrock and located ∼65 and ∼2 km from the front of UI, respectively. We construct along-track elevation changes on UI for several time intervals during 2005-2011, based on ATM, SPOT 5 and Ice, Cloud, and land Elevation Satellite (ICESat) data to assess temporal changes of UI. We estimate a mass loss rate of -6.7±4.2 Gt/yr, over an area of ∼1600 km2. The ice mass loss occurs primarily over the northern glacier of UI. This pattern is also observed ∼40 km upstream, where we observe glacier thinning at a rate of -1.6±0.3 m/yr across the northern portion of UI and -0.5±0.1 m/yr across the southern portion. GPS measurements suggest bedrock uplift rates of 7.6±0.6 mm/yr (UPVK) and 16.2±0.6 mm/yr (SRMP). The modeled ice mass loss of UI causes bedrock uplift rates of 1.3±0.6 mm/yr (UPVK) and 8.3±4.2 mm/yr (SRMP). Including additional contributions from ice mass changes outside UI and from Glacial Isostatic Adjustment (GIA), we obtain total modeled uplift rates of 4.7±0.6 mm/yr (UPVK) and 13.8±4.2 mm/yr (SRMP). The modeled uplift rates from our UI ice mass loss are substantially lower, indicating that additional mass loss is taking place outside of UI. We obtain a difference of 0.6 mm/yr between the modeled and observed relative uplift rates (SRMP relative to UPVK), suggesting that the mass loss of UI is well captured in the model. We observe elevation changes from -15 to -40 m/yr near the front during the period 2005-2011, indicating that UI undergoes large variations in thinning pattern over short time spans.

  7. 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.

  8. Incorporation of Glacier Mass Balance Modelling in the Variable Infiltration Capacity Hydrology Model, with Application to Western Canada

    NASA Astrophysics Data System (ADS)

    Schnorbus, M.; Anslow, F. S.

    2014-12-01

    Mountain glaciers play an important role in the water budget of many basins in western North America. Glacier storage and melt strongly control the seasonality of runoff and can modulate inter-annual variability in glaciarized basins. In particular, glacier runoff can provide a substantial source of streamflow during dry summer months. The importance of glacier runoff from an ecological and water resource perspective, coupled with observations of glacier retreat over recent decades, provides the impetus for accurately simulating runoff from glaciarized regions. The ultimate goal is to derive a greater understanding of the hydrologic response to both climate change and climate variability via improved representation of the cryosphere in hydrologic models. In an effort to more skilfully simulate the cryospheric component of the hydrologic cycle in the mountainous terrain of western North America, we have embarked on a process of updating the macro-scale Variable Infiltration Capacity (VIC) hydrology model to include the ability to simulate glacier mass balance and glacier dynamics. This presentation, which deals with the first part of this effort, reveals progress to date in implementing a process-based representation of glacier accumulation, melt and runoff. We aim to describe the new VIC glacier mass balance model and to present results regarding the testing of the glacier mass balance, water storage and runoff algorithms. Model testing, calibration and validation will be accomplished by confronting the model with observed glacier mass balance and streamflow data collected from several monitoring sites within the western Canadian Cordillera. Challenges with respect to model calibration and application will also be discussed.

  9. 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.

  10. Evolution Into Contact of the Low Mass Close Binary Systems

    NASA Astrophysics Data System (ADS)

    Sarna, M. J.; Fedorova, A. V.

    1989-06-01

    We investigated the effect of mass accretion on the secondary components in close binomy systems (M total ≤ 2.5 M ⊙ M 2,0 ≤ 0.75 M ⊙) exchanging mass in the case A. The evolution of the low-mass close binary systems (M total ≤ 2.5 M ⊙) exchanging the mass in the case A depends on the three main factors: -the initial mass ratio (q 0 = M 2,0/M 1,0), which determines the rate of mass transfer between components; -the inital mass of the secondary component (M 2,0) and -the effectiveness of the heating of the photosphere of the secondary component, by infalling matter. The second factor allows to divide all systems into two essentially different groups: a) systems in which the secondary component is a star with a radiative envelope, or with a thin convection zone in the uppermost layers; b) and systems in which secondary component has a thick convective envelope or is fully convective. The systems from the first group evolve into contact in a characteristic time scale 105 107 years, and reach contact after transfering of 0.03 0.3 M ⊙. The mass exchange proceeds only in a thermal time scale. For the systems from the group b the effectiveness of the heating of the stellar surface is the most important. In the case when the entropy of the newly accreted matter is the same as the surface entropy of the secondary, a convective star should shrink upon accretion. Then contact binaries are not formed. In the case when the entropy of the infalling matter is greater then that on the surface, the reaction of the secondary is different. The radius of the secondary component grows rapidly in response to accretion, and the systems reaches contact after the 103 3 106 years, and after transfer of 0.002 0.2. M ⊙. The reaction of the secondary is determined by the formation of the temperature inversion layer below the stellar surface. Full references in: Sarna, M.J. and Fedorova, A.V. (1988) “Evolutionary status of W UMa-type Binaries — Evolution into contact”, Astron. Astrophys., in press.

  11. Mass spectrometric thermodynamic studies of oxide systems and materials

    NASA Astrophysics Data System (ADS)

    Stolyarova, V. L.

    2016-01-01

    Progress in methods of synthesis of advanced materials as well as utilization of such materials at high temperatures requires information on the vaporization processes and thermodynamic properties of oxide systems. The optimal experimental method for these purposes is high-temperature mass spectrometry. This review summarizes and classifies experimental results obtained in mass spectrometric studies of the high-temperature thermodynamic properties of oxide systems and materials carried out in the last two decades. Published data on the vaporization processes and thermodynamic properties of oxide materials for high-temperature technologies are discussed from the standpoint of acid–base concept and model approaches including statistical thermodynamic methods. The bibliography includes 248 references.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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...

  17. 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.

  18. 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 these gas flows. Based on data collected by the BRITE-Constellation satellite mission, built, launched and operated thanks to support from the Austrian Aeronautics and Space Agency and the University of Vienna, the Canadian Space Agency (CSA), and the Foundation for Polish Science & Technology (FNiTP MNiSW) and National Science Centre (NCN). Based in part also on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programme 093.D-0367(A).

  19. 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 slightly better variance reduction than the unconstrained series. Analysis provided a check on the estimation scheme and pointed to further work to improve the determination of OAM using this method. A significant effort was also devoted to quantifying effects of uncertainties in high frequency winds on the mean and seasonal momentum exchange between atmosphere and oceans.

  20. Crustal uplift due to ice mass variability on Upernavik Isstroem, west Greenland

    NASA Astrophysics Data System (ADS)

    Nielsen, K.; Khan, S. A.; Korsgaard, N.; Kjaer, K. H.; Wahr, J. M.; Bevis, M. G.; Stearns, L. A.; Timm, L. H.

    2012-12-01

    We estimate the mass loss rate of Upernavik Isstroem using surface elevation changes between a SPOT 5 Digital Elevation Model (DEM) from 2008 and NASA's Airborne Topographic Mapper (ATM) data from 2010. To assess the validity of our mass loss estimate, we analyze GPS data between 2007 and 2011 from two continuous receivers, UPVK and SRMP which are established on bedrock and located ~65 and ~2 km from the front of UI, respectively. We construct along-track elevation changes on UI for several time intervals during 2005 - 2011, based on ATM, SPOT 5 and Ice, Cloud, and land Elevation Satellite (ICESat) data to assess temporal changes of UI. We estimate a mass loss rate of -6.7 +/- 4.2 Gt/yr, over an area of ~1600 km^2. The ice mass loss occurs primarily over the northern glacier of UI. This pattern is also observed ~40 km upstream, where we observe glacier thinning at a rate of -1.6 +/- 0.3 m/yr across the northern portion of UI and -0.5 +/-0.1 m/yr across the southern portion. We obtain a difference of 0.6 mm/yr between the modeled and observed relative uplift rates at SRMP relative to UPVK, suggesting that the mass loss of UI is well captured in the model. We observe elevation changes from -15 to -40 m/yr near the front during the period 2005 - 2011, indicating that UI undergoes large variations in thinning pattern over short time spans.

  1. 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.

  2. 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-tension actuators. This control subsystem would continually adjust the cord tension in response to accelerometer feedback to optimize vibration-isolation properties as required for various operating conditions. The control system could also adjust cord tensions (including setting the two cords to different tensions) to suppress resonances. Other future enhancements could include optimizing the cord material, thickness, and braid; optimizing the spoke patterns; and adding longitudinal cords for applications in which longitudinal stiffness and vibration suppression are required.

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

    NASA Astrophysics Data System (ADS)

    Abe, Naoto; Nishioka, Nobuhiro

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

  4. 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.

  5. Orbital periods of cataclysmic variables identified by the SDSS. VII. Four new eclipsing systems

    NASA Astrophysics Data System (ADS)

    Southworth, J.; Copperwheat, C. M.; Gänsicke, B. T.; Pyrzas, S.

    2010-02-01

    We present photometry of nine cataclysmic variable stars identified by the Sloan Digital Sky Survey, aimed at measuring the orbital periods of these systems. Four of these objects show deep eclipses, from which we measure their orbital periods. The light curves of three of the eclipsing systems are also analysed using the lcurve code, and their mass ratios and orbital inclinations determined. SDSS J075059.97+141150.1 has an orbital period of 134.1564 ± 0.0008 min, making it a useful object with which to investigate the evolutionary processes of cataclysmic variables. SDSS J092444.48+080150.9 has a period of 131.2432 ± 0.0014 min and is probably magnetic. The white dwarf ingress and egress phases are very deep and short, and there is no clear evidence that this object has an accretion disc. SDSS J115207.00+404947.8 and SDSS J152419.33+220920.1 are nearly identical twins, with periods of 97.5 ± 0.4 and 93.6 ± 0.5 min and mass ratios of 0.14 ± 0.03 and 0.17 ± 0.03, respectively. Their eclipses have well-defined white dwarf and bright spot ingress and egress features, making them excellent candidates for detailed study. All four of the orbital periods presented here are shorter than the 2-3 h period gap observed in the known population of cataclysmic variables. The reduced observational data presented in this work are available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/510/A100 and at http://www.astro.keele.ac.uk/ jkt/.

  6. DETECTION OF LOW-MASS-RATIO STELLAR BINARY SYSTEMS

    SciTech Connect

    Gullikson, Kevin; Dodson-Robinson, Sarah

    2013-01-01

    O- and B-type stars are often found in binary systems, but the low binary mass-ratio regime is relatively unexplored due to observational difficulties. Binary systems with low mass ratios may have formed through fragmentation of the circumstellar disk rather than molecular cloud core fragmentation. We describe a new technique sensitive to G- and K-type companions to early B stars, a mass ratio of roughly 0.1, using high-resolution, high signal-to-noise spectra. We apply this technique to a sample of archived VLT/CRIRES observations of nearby B stars in the CO bandhead near 2300 nm. While there are no unambiguous binary detections in our sample, we identify HIP 92855 and HIP 26713 as binary candidates warranting follow-up observations. We use our non-detections to determine upper limits to the frequency of FGK stars orbiting early B-type primaries.

  7. 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.

  8. Detection of Low-Mass-ratio Stellar Binary Systems

    NASA Astrophysics Data System (ADS)

    Gullikson, Kevin; Dodson-Robinson, Sarah

    2013-01-01

    O- and B-type stars are often found in binary systems, but the low binary mass-ratio regime is relatively unexplored due to observational difficulties. Binary systems with low mass ratios may have formed through fragmentation of the circumstellar disk rather than molecular cloud core fragmentation. We describe a new technique sensitive to G- and K-type companions to early B stars, a mass ratio of roughly 0.1, using high-resolution, high signal-to-noise spectra. We apply this technique to a sample of archived VLT/CRIRES observations of nearby B stars in the CO bandhead near 2300 nm. While there are no unambiguous binary detections in our sample, we identify HIP 92855 and HIP 26713 as binary candidates warranting follow-up observations. We use our non-detections to determine upper limits to the frequency of FGK stars orbiting early B-type primaries.

  9. 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.

  10. Mass transfer in eccentric binary systems using the binary evolution code BINSTAR

    NASA Astrophysics Data System (ADS)

    Davis, P. J.; Siess, L.; Deschamps, R.

    2013-08-01

    Context. Studies of interacting binary systems typically assume that tidal forces have circularized the orbit by the time Roche lobe overflow (RLOF) commences. However, recent observations of ellipsoidal variables have challenged this assumption. Aims: We present the first calculations of mass transfer via RLOF for a binary system with a significant eccentricity using our new binary stellar evolution code. The study focuses on a 1.50+1.40 M⊙ main sequence binary with an eccentricity of 0.25, and an orbital period of Porb ≈ 0.7 d. The reaction of the stellar components due to mass transfer is analysed, and the evolution of mass transfer during the periastron passage is compared to recent smooth particle hydrodynamics (SPH) simulations. The impact of asynchronism and non-zero eccentricity on the Roche lobe radius, and the effects of tidal and rotational deformation on the stars' structures, are also investigated. Methods: Calculations were performed using the state-of-the-art binary evolution code BINSTAR, which calculates simultaneously the structure of the two stars and the evolution of the orbital parameters. Results: The evolution of the mass transfer rate during an orbit has a Gaussian-like shape, with a maximum at periastron, in qualitative agreement with SPH simulations. The Roche lobe radius is modified by the donor star's spin and the orbital eccentricity. This has a significant impact on both the duration and the rate of mass transfer. We find that below some critical rotation rate, mass transfer never occurs, while above some threshold, mass is transferred over the entire orbit. Tidal and rotational deformation of the donor star causes it to become over-sized, enhancing the mass transfer rate further by up to about a factor of ten, leading to non-conservative mass transfer. The modulation of the mass transfer rate with orbital phase produces short-term variability in the surface luminosity and radius of each star. The longer-term behaviour shows, in accordance with studies of circular systems with radiative stars, that the donor becomes ever small and under-luminous, while the converse is the case for the accretor.

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

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

    A comprehensive study of the mass sensitivity of the vibration-rotation-inversion transitions of 14NH3, 15NH3, 14ND3 and 15ND3 is carried out variationally using the TROVE approach. Variational calculations are robust and accurate, offering a new way to compute sensitivity coefficients. Particular attention is paid to the Δk = ±3 transitions between the accidentally coinciding rotation-inversion energy levels of the ν2 = 0+, 0-, 1+ and 1- states, and the inversion transitions in the ν4 = 1 state affected by the `giant' l-type doubling effect. These transitions exhibit highly anomalous sensitivities, thus appearing as promising probes of a possible cosmological variation of the proton-to-electron mass ratio μ. Moreover, a simultaneous comparison of the calculated sensitivities reveals a sizeable isotopic dependence which could aid an exclusive ammonia detection.

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

    SciTech Connect

    Córsico, A.H.; Althaus, L.G.; Mukadam, A.S.; García-Berro, E.; Corti, M.A. E-mail: althaus@fcaglp.unlp.edu.ar E-mail: anjum@astro.washington.edu E-mail: isern@ice.cat E-mail: mariela@fcaglp.fcaglp.unlp.edu.ar

    2012-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  14. Clinical and hormonal variables related to bone mass loss in anorexia nervosa patients.

    PubMed

    Fernández-Soto, María Luisa; González-Jiménez, Amalia; Chamorro-Fernández, Marta; Leyva-Martínez, Socorro

    2013-01-01

    A better understanding of the prognostic factors of low bone mass in anorexia nervosa (AN) and development of effective therapeutic strategies is critical. In order to determine which clinical, biochemical, and/or hormonal parameters could be related to bone mineral density (BMD), 47 female AN patients were classified according to the WHO osteoporosis criteria at lumbar spine (LS). This was a cross-sectional study of 16 AN women with osteoporosis criteria and 31without. Control group was 25 healthy, normal-weight, age-matched women. We assessed BMD using dual-energy X-ray absorptiometry at the LS and body composition. We measured serum fasting cortisol, estradiol, insulin-like growth factor-1 (IGF-1), leptin, sex hormone-binding globulin, albumin and retinol binding protein levels. The prevalence of osteoporosis was 34% and osteopenia 19% at the LS. The AN group with osteoporosis had lower IGF-1 and estradiol levels (both p<0.001), lower serum leptin (p<0.02), and higher cortisolemia (p<0.03) levels compared with AN group without osteoporosis. The BMD and T-score at LS was inversely related to the duration of amenorrhea (p<0.02) and directly related to body mass index (BMI, p<0.002), total fat mass (p<0.03), serum IGF-1 (p<0.01), and estradiol levels (p<0.001) in AN patients. We conclude that AN women with a significant BMD loss have a high risk of developing osteoporosis. A low BMD is a consequence of hormonal alterations which include hypoestrogenism, hypoleptinemia, hypercortisolism, and decreases in IGF-1 levels, as well as a low BMI and fat mass. PMID:23601428

  15. 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.

  16. Interannual-to-interdecadal variability of the Yellow Sea Cold Water Mass in 1967-2008: Characteristics and seasonal forcings

    NASA Astrophysics Data System (ADS)

    Park, Sunghyea; Chu, Peter C.; Lee, Jae-Hak

    2011-09-01

    We identified characteristics of interannual-to-interdecadal variability of the Yellow Sea Cold Water Mass and examined mechanisms to generate variability using the Korea Oceanographic Data Center dataset. Regional/background variables (sea level pressure (SLP), surface air temperature (SAT), and sea surface temperature (SST)) and five climate indices were used to explore the linkage to seasonally-differential forcings. The first EOF mode (53%) represents warming/cooling over the entire bottom cold water with the dominant periods of 2-7 and 10-20 years. Three cold and two warm events occur in 1967-2008. The variability preliminarily attributes to previous winter surface forcings; however, summer surface forcings intensify bottom cold water temperature anomaly (BWTa) induced in the previous winter and also trigger a new anomaly, especially in the cold event after 1996. Cold events relate to the winter forcing (strengthening of the Siberian High, the Aleutian Low, East Asian Jet Stream, Pacific Decadal Oscillation, and Arctic Oscillation) and the summer forcing (increased SLP in the Asian continent and the Aleutian Islands and increased SST in the Kuroshio and the Alaskan Current). In both seasons, SST and SAT anomalies on the tropical to subtropical western North Pacific are strongly correlated to BWTa; however, mechanisms are different.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. Mean Circulation and Water Masses and Their Variability in the Western Tropical Pacific and Eastern Tropical Indian Ocean

    NASA Astrophysics Data System (ADS)

    Riser, S.

    2014-12-01

    Circulation patterns in both the western tropical Pacific and eastern tropical Indian Ocean are examined in the context of upper ocean streamfunction estimates derived from Argo floats and other historical observations. The flow and water mass characteristics of the Pacific input to the Indonesian throughflow and the output in the Indian Ocean are compared and contrasted. It is shown that the upper ocean waters exiting Indonesia can be traced into the central Indian Ocean. The variability in the decadal-mean streamfunction is considerable, especially in the western Pacific warm pool. The water mass differences across Indonesia highlight the importance of this region in determining the upper ocean properties of the eastern Indian Ocean and the need for better direct observations of the processes responsible for these transformations.

  2. Analysis of mass transfer in dissipative nonideal systems: Numerical simulation

    SciTech Connect

    Vaulina, O. S.; Adamovich, K. G.

    2008-05-15

    The results of a numerical analysis of mass transfer in extended quasi-two-dimensional and three-dimensional dissipative nonideal systems are presented. Pair interaction between particles is modeled by isotropic repulsive potentials represented by combinations of power laws and exponentials. Simulations are performed for parameter values characteristic of laboratory dusty plasmas. It is shown that short-time particle dynamics in nonideal liquid systems is similar to evolution of thermal oscillations at crystal lattice sites.

  3. High-resolution stellar vidicon spectrophotometry. I - Variable mass loss from Arcturus and the hypothesis of giant convective elements

    NASA Technical Reports Server (NTRS)

    Chiu, H. Y.; Adams, P. J.; Linsky, J. L.; Basri, G. S.; Maran, S. P.; Hobbs, R. W.

    1977-01-01

    High-resolution spectrophotometry of the variable Ca II K line in the K2 IIIp star Alpha Boo was performed with the McMath Solar Telescope at Kitt Peak National Observatory and an experimental SEC vidicon camera. The results are compared with Copernicus observations of the Mg II h and k lines and with earlier Ca II data. It is found that either of two states may typically occur in the Arcturus chromosphere. From comparison with the results of model calculations for expanding chromospheres, it is concluded that these correspond respectively to a 'normal' state in which the mass loss is less than one billionth of a solar mass per year and an 'abnormal' state in which the mass loss is about 8 billionths of a solar mass per year. In the latter case, the expansion velocity is around 13 km/s at optical depth unity in the K-line, which exceeds the local sound speed. It is suggested that the abnormal state represents the rise to the photosphere of a very large convective element, as hypothesized for red giants by Schwarzschild (1975).

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

    NASA Astrophysics Data System (ADS)

    Velicogna, I.; Wahr, J.

    2013-06-01

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

  5. Water mass and transport variability in the North Sea in climate change simulations

    NASA Astrophysics Data System (ADS)

    Klein, Birgit; Bülow, Katharina; Dieterich, Christian; Ganske, Anette; Heinrich, Hartmut; Hüttl-Kabus, Sabine; Markovic, Michaela; Mayer, Bernhard; Meier, Markus; Mikolajewicz, Uwe; Narayan, Nikesh; Pohlmann, Thomas; Rosenhagen, Gudrun; Sein, Dmitry; Su, Jian

    2013-04-01

    Regionalized climate change simulations for the North and Baltic Sea are carried out with coupled ocean atmosphere models in the framework of the research program KLIWAS. The numerical simulations are performed by the Max-Planck Institute for Meteorology (MPI), the Swedish Meteorological and Hydrological Institute (SMHI) and the Institute of Oceanography (IfM Hamburg). Output from the models is analyzed jointly with the Federal Maritime service (BSH) and the German weather service (DWD/SWA). Since one of the ocean models (MPI-OM) is global in extent it simulates the exchange between Atlantic and North Sea according to the physical forcing, while the other two models are shelf models and thus require boundary conditions at the open model boundaries (English Channel, northern shelf edge, Baltic). The warming and freshening of the North Sea is compared between the different models and related to the atmospheric forcing. Transport variability is analyzed from the MPIOM simulations. The temperature and transport variability at the northern shelf edge of the North Sea is closely related to the dominant atmospheric circulation (NAO) but shows no obvious trend until 2100 in the A1B scenarios. The Baltic outflow variability on the other hand is dominated by a 30 year cycle associated with strong salinity anomalies. In accordance with observations, the models simulate a low salinity period in Baltic waters for the period 1980-2010. Only the English Channel transport shows a long-term trend with a major decline of Atlantic inflow at the end of the 20th century followed by a slow and steady decline until 2100. The transport variability in the English Channel is correlated with the sea level distribution in the northeastern Atlantic. The reduced inflow through the English Channel results in a slower circulation in the southern North Sea with reductions in current speed in the order of 20%. The simulated wind fields in these runs do not support a deceleration of the circulation since southwesterly winds are increasing, these trends however are not significant.

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

    NASA Astrophysics Data System (ADS)

    Seifahrt, A.; Röll, T.; Neuhäuser, R.; Reiners, A.; Kerber, F.; Käufl, H. U.; Siebenmorgen, R.; Smette, A.

    2008-06-01

    We present a refined orbital solution for the components A, B, and C of the nearby late-M type multiple system LHS 1070. By combining astrometric datapoints from NACO/VLT, CIAO/SUBARU, and PUEO/CFHT, as well as a radial velocity measurement from the newly commissioned near infrared high-resolution spectrograph CRIRES/VLT, we achieve a very precise orbital solution for the B and C components and a first realistic constraint on the much longer orbit of the A-BC system. Both orbits appear to be co-planar. Masses for the B and C components calculated from the new orbital solution (M_B+C = 0.157 ± 0.009 {M⊙}) are in excellent agreement with theoretical models, but do not match empirical mass-luminosity tracks. The preliminary orbit of the A-BC system reveals no mass excess for the A component, giving no indication for a previously proposed fourth (D) component in LHS 1070. Based on observations made with ESO Telescopes at the Paranal Observatory under programme ID 60.A-9078(A) and 79.C-0106(A), as well as data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan. Based also on observations obtained at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii.

  7. 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).

  8. 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} .

  9. Stability of multiphased rotating fluid systems subjected to variable gravitational forces, phase 3

    NASA Astrophysics Data System (ADS)

    Ward, Charles A.; Yee, D.; Wade, J. A.; Dickstein, P. A.

    1991-05-01

    A thermodynamic method was developed to predict the shape of the phase boundary in isothermal, constant volume, constant mass, rotating, two phase fluid systems. The shape is predicted in terms of experimentally controllable variables for the system. A nondimensional parameter is then defined, and provided that it is small compared to unity, gravitational effects may be neglected. A set of experiments was performed under conditions where this restriction is satisfied. It is found that the length of the vapor phase may be predicted with the proposed method. An experimental study was also conducted in KC-135 flights to examine the stability of the fluid-fluid interphase in a rotating fluid system in which a gravitational field is applied perpendicular to the axis of rotation. The parameters which govern stability were determined. A method was also developed to predict the equilibrium configurations of a droplet rotating in an isothermal, closed, constant size volume. If the complete conditions for thermodynamic equilibrium are imposed, the possible shapes of the droplet may be predicted in terms of experimentally controlled variables. Finally, theory was applied to develop a method for determining interfacial tensions from the measurement of both the shape of a rotating drop and the shape of a sessile drop.

  10. 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 media, and the tapes are used as backup media. The storage system is managed by the IEEE mass storage reference model-based UniTree software package. UniTree software will keep track of all files in the system, will automatically migrate the lesser used files to archive media, and will stage the files when needed by the system. The user can access the files without knowledge of their physical location. The high-performance mass storage system developed by Loral AeroSys will significantly boost the system I/O performance and reduce the overall data storage cost. This storage system provides a highly flexible and cost-effective architecture for a variety of applications (e.g., realtime data acquisition with a signal and image processing requirement, long-term data archiving and distribution, and image analysis and enhancement).

  11. 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. PMID:26096956

  12. ANGULAR MOMENTUM AND GALAXY FORMATION REVISITED: EFFECTS OF VARIABLE MASS-TO-LIGHT RATIOS

    SciTech Connect

    Fall, S. Michael; Romanowsky, Aaron J.

    2013-06-01

    We rederive the relation between the specific angular momentum j {sub *} and the mass M {sub *} of the stellar matter in galaxies of different morphological types. This is a revision of the j {sub *}-M {sub *} diagram presented in our recent comprehensive study of galactic angular momentum. In that work, we estimated j {sub *} from kinematic and photometric data that extended to large radii and M {sub *} from near-infrared luminosities L{sub K} with an assumed universal mass-to-light ratio M {sub *}/L{sub K} . However, recent stellar population models show large variations in M {sub *}/L{sub K} correlated with B V color. In the present work, we use this correlation to estimate M {sub *}/L{sub K} and hence M {sub *} from the measured B V and L{sub K} . Our revised j {sub *}-M {sub *} diagram is similar to our previous one; both disk-dominated and elliptical galaxies follow nearly parallel sequences with j{sub ?}?M{sub ?}{sup ?} and ? = 0.6 0.1. However, the offset between the sequences is now a factor of about 5, some 30% larger than before (and close to the offset found by Fall in 1983). Thus, our new results place even tighter constraints on the loss of specific angular momentum by galactic disks over their lifetimes.

  13. Mass transfer effects on the unsteady mhd radiative- convective flow of a micropolar fluid past a vertical porous plate with variable heat and mass fluxes

    NASA Astrophysics Data System (ADS)

    Reddy, M. Gnaneswara

    2013-03-01

    The problem of unsteady two-dimensional laminar flow of a viscous incompressible micropolar fluid past a vertical porous plate in the presence of a transverse magnetic field and thermal radiation with variable heat and mass fluxes is considered. The free stream velocity is subjected to exponentially increasing or decreasing small perturbations. A uniform magnetic field acts perpendicularly to a porous surface where a micropolar fluid is absorbed with a suction velocity varying with time. The Rosseland approximation is used to describe radiative heat transfer in the limit of optically thick fluids. The effects of the flow parameters and thermophysical properties on the velocity and temperature fields across the boundary layer are investigated. The effects of various parameters on the velocity, microrotation velocity, temperature, and concentration profiles are given graphically, and the values of the skin friction and couple stress coefficients are presented.

  14. Variability of Southern Valu Fa Ridge Magmatic Systems

    NASA Astrophysics Data System (ADS)

    Goddard, C. I.; Christie, D. M.; Arculus, R.

    2004-12-01

    Valu Fa Ridge (VFR), which encompasses the southernmost segments of the East Lau Spreading Center (ELSC), is an important end-member in the spectrum of back-arc spreading centers because it is strongly affected in all aspects of the spreading process by inputs from the nearby active Tofua (Tonga) volcanic arc, and because its magma systems are rapidly evolving as the VFR propagates to the south. New lava samples collected by the TELVE Expedition of the R/V Southern Surveyor (Australia) from the four southernmost VFR segments have greatly increased the number and spatial distribution of fresh volcanic glass samples, quadrupling the availability of "primitive" (MgO > 6 wt.%) glass samples and encompassing significant along- and across-axis geochemical variability. These new data provide an opportunity to evaluate both the evolution of crustal magmatic processes relative to southward rift propagation and variability in mantle source inputs relative to the active volcanic arc. The four sampled segments of VFR are separated by left-stepping overlapping offsets that differ from their mid-ocean ridge counterparts in their longer, more parallel overlapping limbs and in the absence of an overlap basin. The TELVE glasses display considerable major element variability and the VFR is unusual among well-developed spreading centers in its strongly bimodal volcanism, in the abundance of evolved lavas and in the coexistence of two distinct liquid lines of descent. Dacites and rhyolites (SiO2 ~67-75 wt.%) are relatively abundant close to segment ends or discontinuities along the southernmost three ridge segments, but rare from the northernmost sampled segment and from off-axis seamounts. A "Daly Gap" from ~60-67 wt.% SiO2 and 1.75-0.75 wt.% MgO is present along the northern segments but absent near the southern propagating rift tip. Primitive (MgO > 6wt.%) glasses were recovered from all VFR segments and on 5 of the 9 sampled seamounts. Both high-silica glasses and FeTi basalt glasses appear to represent the culmination of simple crystal fractionation trends derived from similar tholeiitic parental compositions that bifurcate between 5 and 6 wt. % MgO. Lavas from the off-axis seamounts, both east and west of VFR, are systematically more mafic than the on-axis samples and most have higher K2O contents. A single boninitic glass recovered from seamount K-11 is similar in composition to melts reported in a xenolith from the same seamount by Kamenetsky et al. (EPSL, 151, 205, 1997). At its southern end, the VFR is propagating into old arc crust of unknown age. If the high silica lavas are excluded, along-axis major element trends define a typical rift propagation pattern. High-silica lavas occur sporadically with no apparent relationship to the petrologic trends defined by the more mafic lavas, suggesting that magmas only fractionate to high SiO2 compositions under ideal, localized conditions. Of particular interest is the possibility that the high-Si trend is initiated and/or facilitated by changes in oxygen fugacity, perhaps initiated by assimilation of hydrated pre-existing crustal material. Preliminary trace element data for the southern VFR segments show the characteristic Nb and Ta depletions associated with volcanic arc sources, confirming the strong input from the volcanic arc to the back-arc mantle source region. More complete spatial coverage is expected to help define the extent and, perhaps the pathways, of this mantle input.

  15. 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

  16. Dynamic flame probe mass spectrometry and condensed-system decomposition

    SciTech Connect

    Korobeinichev, O.P.

    1988-03-01

    Dynamic flame probe mass spectrometry was evaluated for its ability to diagnose the stages and chemical aspects of flame, pyrolysis, and combustion mechanisms for gas and condensed systems. The method provides flame component identification, composition determination, and concentration distribution measurement (flame structure research), from which the concentration fluxes and reaction rates can be calculated. Its advantages over spectroscopic methods with flames are its ability to record all the particles and its high spatial resolution. The method has been used to research combustion mechanisms for simple types of condensed systems such as ammonium perchlorate and four-element hexogen. Research aspects involve extending the applications to higher pressures and to systems containing five or more elements. The most rapid advances can come from combining mass spectrometry with microthermocouple methods and induced Raman scattering.

  17. A mass sensitivity analysis of lunar orbiting beam power systems

    NASA Technical Reports Server (NTRS)

    Stavnes, Mark W.; Cull, Ronald C.

    1991-01-01

    At NASA Lewis Research Center, the feasibility of beaming power from orbiting satellites to the surface of the moon was studied. Reference microwave and laser beam power concepts were found to be 1/3 to 1/6 the mass of surface solar systems. Further analysis was performed to determine the sensitivity of the reference concepts to technology performance levels and mission architecture scenarios, such as beaming to multiple surface sites and lunar rovers. Previous studies concluded that frequencies above 35 GHz for the microwave systems were not critical for reducing the main base mass; however, when multiple sites and rovers are considered, this may become necessary. In addition, for the laser system, the pointing accuracy of the satellites becomes a critical factor for rover applications. These issues and other important results of the parametric studies, are discussed.

  18. 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.

  19. The HD 5980 multiple system: Masses and evolutionary status

    SciTech Connect

    Koenigsberger, Gloria; Gamen, Roberto; Barbá, Rodolfo E-mail: nmorrell@lco.edu E-mail: rgamen@fcaglp.unlp.edu.ar E-mail: ngonzalez@astro.uni-bonn.de E-mail: rbarba@dfuls.cl

    2014-10-01

    New spectroscopic observations of the LBV/WR multiple system HD 5980 in the Small Magellanic Cloud are used to address the question of the masses and evolutionary status of the two very luminous stars in the 19.3 day eclipsing binary system. Two distinct components of the N V 4944 Å line are detected in emission and their radial velocity variations are used to derive masses of 61 and 66 M {sub ☉}, under the assumption that binary interaction effects on this atomic transition are negligible. We propose that this binary system is the product of quasi-chemically homogeneous evolution with little or no mass transfer. Thus, both of these binary stars may be candidates for gamma-ray burst progenitors or even pair instability supernovae. Analysis of the photospheric absorption lines belonging to the third-light object in the system confirm that it consists of an O-type star in a 96.56 day eccentric orbit (e = 0.82) around an unseen companion. The 5:1 period ratio and high eccentricities of the two binaries suggest that they may constitute a hierarchical quadruple system.

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

    DOEpatents

    Reilly, Peter T. A. [Knoxville, TN

    2010-12-14

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

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

    DOEpatents

    Reilly, Peter T.A.

    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.

  2. 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.

  3. 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

  4. Mass Polarization Effect in He-like Systems

    NASA Technical Reports Server (NTRS)

    Bhatia, A. K.; Drachman, Richard J.; Fisher, Richard R. (Technical Monitor)

    2002-01-01

    Eigenvalues for the ground state S and excited S and P states have been calculated for He-like systems, He, Li(+), Be(+2), and Ne(+8), using Hylleraas-type wave functions. These calculations have been carried out for a number of mass ratios R=mu/M=m(sub e)/(m(sub e)+M), where m(sub e) is the mass of the electron and M is the arbitrary mass of the nucleus. The eigenvalues are fitted to a 5th degree polynomial in R giving the mass polarization term (Delta (sub 1) x Delta (sub 2) and higher order corrections. The mass polarization term obtained from the fitting procedure agrees very well with the first-order result obtained directly. For example, in He we find E=E(sub 0)+Sigma(sup 5)(sub n=1)R(sup n)C(sub n), where E(sub 0)=-5.807448754 Ry and C(sub 1)=0.318138927 which agrees very well with the directly obtained first-order value 0.318138966083 and the result 0.318372 obtained by Yamanaka, using wave functions of the configuration-interaction form. We have carried out a similar calculation for the bound state of H(-).

  5. Nevada Monitoring System to Assess Climate Variability and Change

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

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

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

    NASA Astrophysics Data System (ADS)

    Scholz, Alexander; Mužić, Koraljka; Geers, Vincent

    2015-07-01

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

  7. Miniature mass spectrometer systems based on a microengineered quadrupole filter.

    PubMed

    Malcolm, Andrew; Wright, Steven; Syms, Richard R A; Dash, Neil; Schwab, Marc-André; Finlay, Alan

    2010-03-01

    Two miniature mass spectrometer systems based on a microengineered quadrupole mass filter have been developed. One of the instruments has a footprint of 27 cm x 20 cm and is intended for laboratory use when space is at a premium. The other is portable and intended for use in the field. It is battery powered, weighs 14.9 kg, and is housed in a rugged case. This is the first example of a portable mass spectrometer incorporating an analyzer fabricated using microelectromechanical systems (MEMS) techniques. The starting material for construction of the filters is a bonded silicon on insulator substrate, which is selectively etched using batch processing techniques to form coupling optics and springs that accurately hold 0.5 mm diameter stainless steel rods in the required geometry. Assembled filters measure 35 mm x 6 mm x 1.5 mm and are mounted, together with an ion source and channeltron detector, in small, interchangeable cartridges, which plug into a 220 cm(3) vacuum chamber. Recovery from accidental contamination or when servicing is required can be achieved within 5-10 min, as the cartridge is easily exchanged with a spare. A potential application to environmental monitoring has been investigated. The headspace above water spiked with dibutyl mercaptan was sampled with a solid phase microextraction (SPME) fiber, which was then injected directly into the vacuum chamber of the mass spectrometer. Using this method, the limit of detection was found to be approximately 5 ppm for a 15 s sampling period. PMID:20108919

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

    PubMed

    Pe?ar, Darja; Gorek, 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. PMID:25830982

  9. 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.

  10. Mass-Independent Fractionation of Mercury in Hydrothermal Systems

    NASA Astrophysics Data System (ADS)

    Sherman, L. S.; Blum, J. D.; Nordstrom, D. K.; McCleskey, R. B.; Barkay, T.; Vetriani, C.

    2008-12-01

    Experimental results indicate that mass-independent fractionation (MIF) of mercury occurs during both photochemical reduction of Hg2+ and photochemical demethylation of methyl-mercury. In aqueous systems, the photochemical reduction of Hg2+aq to Hg0aq and subsequent evasion of Hg0g preferentially retains the odd mass isotopes of Hg in the aqueous phase and releases the even mass isotopes of Hg in Hg0g. MIF of Hg has been observed recently in marine and freshwater fish, soils, peat, mosses and sediments. We investigated Hg in modern volcanic-hydrothermal systems to evaluate whether major earth reservoirs carry a MIF signature. Hydrothermal systems driven by mantle-derived volcanism are a major natural source of Hg to the atmosphere and may represent the isotopic composition of deep geological reservoirs. We analyzed fluid and siliceous sinter samples from hot springs in the Yellowstone Plateau volcanic field and vent chimney precipitates from the Guaymas Basin sea-floor rift. In all of the analyzed fluid and sinter samples from Ojo Caliente hot spring in Yellowstone, we observed a small but significant positive MIF (Δ199Hg = 0.13‰ ± 0.06‰, 2SD). No significant MIF was measured in any of the sea-floor rift samples from Guaymas Basin. In Ojo Caliente, Hg is both lost from the fluids and fractionated mass-dependently along a flow path from the hot spring vent to the outflow channel. We suggest that Hg loss and mass-dependent fractionation occur in this system due to volatilization of Hg0aq to Hg0g. In contrast, because all of the samples measured from Ojo Caliente exhibited approximately the same degree of MIF, it is not likely that measurable photochemical reduction of Hg is occurring in this system on the short timescale (i.e., minutes) of fluid discharge. Instead, we suggest that either (1) some portion of the Hg in the system was photochemically reduced at the earth's surface in the past and transported back to the subsurface (perhaps by groundwater infiltration) or (2) Hg is leached into the hydrothermal system from sediments containing an MIF signature. The lack of MIF in vent chimney samples from Guaymas Basin suggests that because Hg in that sea-floor rift hydrothermal system is isolated from light, it has not been affected by the photochemical reactions that cause MIF of Hg.

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  13. Using Variable Ionization Energy Time-of-Flight Mass Spectrometry with Comprehensive GC×GC To Identify Isomeric Species.

    PubMed

    Alam, Mohammed S; Stark, Christopher; Harrison, Roy M

    2016-04-19

    Although GC×GC-ToF-MS allows the separation of thousands of peaks, many of these peaks are not positively identified owing to the lack of mass spectral library data and/or standard materials, leading to a substantial amount of information being inaccessible. The fragmentation patterns of molecules in mass spectrometers using electron impact ionization at 70 eV can be useful for molecule identification, provided a match is available in a published EI MS library, but are indistinguishable for many isomeric organic compounds (for example, linear and branched alkanes). Lower ionization energies have been exploited leading to organic compounds being ionized with lower excess internal energy and less fragmentation, retaining the molecular ion and maximizing its relative signal. This has enabled the identification of a large number of isomeric organic compounds, both aliphatic and aromatic, between C12-C36, in the previously unresolved complex mixture (UCM) of two motor oil samples. This technique also demonstrates problems associated with separation of coeluting isomers, particularly for the n-alkanes, which are routinely measured by 1D GC/MS and may be overestimated, due to coelution. As a consequence retention times in 2 dimensions and mass spectra at variable ionization energies are shown to give unparalleled power to identify specific isomers. PMID:26981641

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

    NASA Technical Reports Server (NTRS)

    Chao, Benjamin F.

    2004-01-01

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

  15. A body shape index and heart rate variability in healthy indians with low body mass index.

    PubMed

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

    2014-01-01

    Background. One third of Indian population is said to be suffering from chronic energy deficiency (CED), with increased risk of developing chronic diseases. A new anthropometric measure called A Body Shape Index (ABSI) is said to be a better index in predicting risks for premature mortality. ABSI is also in part said to be a surrogate of visceral fat. Objective. The present study aimed to explore the association between indices of HRV (heart rate variability), BMI, WC, and ABSI in healthy Indian males with low BMI (BMI < 18.5 kg/m(2)) and to compare with normal BMI group (BMI 18.5 to 24.9 kg/m(2)). Methodology. ABSI and BMI were derived from anthropometric parameters, namely, height, weight, and waist circumference in 178 males aged 18 to 78 years. Subjects were categorized into two groups based on their BMI. Results and Conclusions. Power spectral analysis of HRV demonstrated a significant negative correlation between Log HF (high frequency) and ABSI in both low BMI [-24.2 (9.4), P < 0.05] and normal BMI group [-23.41 (10.1), P < 0.05] even after controlling for age. Thus even with slight increase in BMI among low BMI individuals, there could be a greater risk of cardiovascular morbidity and mortality. PMID:25371818

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

    PubMed Central

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

    2014-01-01

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

  17. 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.

  18. Flow characteristics and particle mass and number concentration variability within a busy urban street canyon

    NASA Astrophysics Data System (ADS)

    Weber, Stephan; Kuttler, Wilhelm; Weber, Konradin

    Mean and turbulent flow characteristics together with particle concentrations were measured in a busy urban street canyon in Essen, Germany, at five (flow characteristics) and three heights (particles) above ground, respectively. Particle mass and number concentrations were sampled in the size range 0.3< Dp<10 μm. The flow characteristics within the canyon were significantly influenced by canyon geometry and were shown to have significant impact on particle concentrations. During flow being directed perpendicular to the canyon a vortex circulation leads to a doubling of ambient particles when the measurement site is situated upwind to ambient flow. The vertical profiles of fine particles have maximum vertical differences of 12% between measurement levels. In the upper part of the canyon, concentrations decrease due to enhanced turbulence and mixing. Significant differences in the dynamics of particle number concentration for different size ranges are analysed. While submicron particles are inversely related to turbulence parameters, i.e. lower concentrations during enhanced turbulence, coarser particles (1< Dp<10 μm) are positively correlated to mixing within the canyon.

  19. 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.

  20. The automation of an inlet mass flow control system

    NASA Technical Reports Server (NTRS)

    Supplee, Frank; Tcheng, Ping; Weisenborn, Michael

    1989-01-01

    The automation of a closed-loop computer controlled system for the inlet mass flow system (IMFS) developed for a wind tunnel facility at Langley Research Center is presented. This new PC based control system is intended to replace the manual control system presently in use in order to fully automate the plug positioning of the IMFS during wind tunnel testing. Provision is also made for communication between the PC and a host-computer in order to allow total animation of the plug positioning and data acquisition during the complete sequence of predetermined plug locations. As extensive running time is programmed for the IMFS, this new automated system will save both manpower and tunnel running time.

  1. Avoiding transthoracic echocardiography and transesophageal echocardiography for patients with variable body mass indexes in infective endocarditis

    PubMed Central

    Sogomonian, Robert; Alkhawam, Hassan; Vyas, Neil; Jolly, JoshPaul; Nguyen, James; Haftevani, Emma A. Moradoghli; Al-khazraji, Ahmed; Ashraf, Amar

    2016-01-01

    Background Echocardiography has been a popular modality used to aid in the diagnosis of infective endocarditis (IE) with the modified Duke criteria. We evaluated the necessity between the uses of either a transthoracic echocardiography (TTE) or transesophageal echocardiography (TEE) in patients with a body mass index (BMI) greater than or equal to 25 kg/m2 and less than 25 kg/m2. Methods A single-centered, retrospective study of 198 patients between 2005 and 2012 diagnosed with IE based on modified Duke criteria. Patients, required to be above age 18, had undergone an echocardiogram study and had blood cultures to be included in the study. Results Among 198 patients, two echocardiographic groups were evaluated as 158 patients obtained a TTE, 143 obtained a TEE, and 103 overlapped with TEE and TTE. Out of these patients, 167 patients were included in the study as 109 (65%) were discovered to have native valve vegetations on TEE and 58 (35%) with TTE. TTE findings were compared with TEE results for true negatives and positives to isolate valvular vegetations. Overall sensitivity of TTE was calculated to be 67% with a specificity of 93%. Patients were further divided into two groups with the first group having a BMI ≥25 kg/m2 and the subsequent group with a BMI <25 kg/m2. Patients with a BMI ≥25 kg/m2 who underwent a TTE study had a sensitivity and specificity of 54 and 92%, respectively. On the contrary, patients with a BMI < 25 kg/m2 had a TTE sensitivity and specificity of 78 and 95%, respectively. Conclusions Patients with a BMI <25 kg/m2 and a negative TTE should refrain from further diagnostic studies, with TEE strong clinical judgment is warranted. Patients with a BMI ≥ 25 kg/m2 may proceed directly to TEE as the initial study, possibly avoiding an additional study with a TTE. PMID:27124167

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. 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

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

    PubMed Central

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

    2012-01-01

    Evidence for a major role of genetic factors in the determination of body mass index (BMI) comes from studies of related individuals. Despite consistent evidence for a heritable component of BMI, estimates of BMI heritability vary widely between studies and the reasons for this remain unclear. While some variation is natural due to differences between populations and settings, study design factors may also explain some of the heterogeneity. We performed a systematic review that identified 88 independent estimates of BMI heritability from twin studies (total 140,525 twins) and 27 estimates from family studies (42,968 family members). BMI heritability estimates from twin studies ranged from 0.47 to 0.90 (5th/50th/95th centiles: 0.58/0.75/0.87) and were generally higher than those from family studies (range: 0.24–0.81; 5th/50th/95th centiles: 0.25/0.46/0.68). Meta-regression of the results from twin studies showed that BMI heritability estimates were 0.07 (P = 0.001) higher in children than in adults; estimates increased with mean age among childhood studies (+0.012/year, P = 0.002), but decreased with mean age in adult studies (−0.002/year, P = 0.002). Heritability estimates derived from AE twin models (which assume no contribution of shared environment) were 0.12 higher than those from ACE models (P < 0.001), whilst lower estimates were associated with self reported versus DNA-based determination of zygosity (−0.04, P = 0.02), and with self reported versus measured BMI (−0.05, P = 0.03). Although the observed differences in heritability according to aspects of study design are relatively small, together, the above factors explained 47% of the heterogeneity in estimates of BMI heritability from twin studies. In summary, while some variation in BMI heritability is expected due to population-level differences, study design factors explained nearly half the heterogeneity reported in twin studies. The genetic contribution to BMI appears to vary with age and may have a greater influence during childhood than adult life. PMID:22645519

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

    USGS Publications Warehouse

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

    2001-01-01

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

  9. 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.

  10. 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.

  11. 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...

  12. 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...

  13. On the interannual variability of the ocean atmospheric system

    NASA Technical Reports Server (NTRS)

    Reiter, E. R.

    1977-01-01

    Several feedback mechanisms between ocean and atmosphere are discussed, which seem to have a decisive influence on the interannual variability of the atmosphere, and on climatic fluctuations of a time scale of 10 to 50 years. Satellite requirements to monitor these feedback processes are outlined briefly.

  14. 23 CFR 810.308 - Approval of urban system nonhighway public mass transit projects.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 23 Highways 1 2012-04-01 2012-04-01 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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. PMID:16710412

  20. 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.

  1. 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.

  2. 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 profile variability (V/R ratio) timescales are shorter and the Hα equivalent widths are smaller in Be/X-ray binaries than in isolated Be stars; and vii) we provide new evidence that the disk in Be/X-ray binaries is, on average, denser than in classical Be stars. Conclusions: We carried out the most complete optical spectroscopic study of the global properties of high-mass X-ray binaries with the analysis of more than 1100 spectra from 20 sources. Our results provide further evidence for the truncation of the disk in Be/X-ray binaries. We conclude that the interaction between the compact object and the Be-type star works in two directions: the massive companion provides the source of matter for accretion, affecting the surroundings of the compact object, and the continuous revolution of the neutron star around the optical counterpart also produces the truncation of the Be star's equatorial disk. The reduced spectra as FITS files are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/590/A122

  3. 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.

  4. 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

  5. Evaluation of small mass spectrometer systems for permanent gas analysis.

    PubMed

    Arkin, C Richard; Griffin, Timothy P; Ottens, Andrew K; Diaz, Jorge A; Follistein, Duke W; Adams, Fredrick W; Helms, William R

    2002-08-01

    This work is aimed at understanding the aspects of designing a miniature mass spectrometer (MS) system. Several types of small MS systems are evaluated and discussed, including linear quadrupole, quadrupole ion trap, time of flight, and sector. Analysis of hydrogen, helium, oxygen, and argon in a nitrogen background with the concentrations of the components of interest ranging from 0 to 5000 parts per million (ppm). The performance of each system in terms of accuracy, precision, limits of detection, response time, recovery time, scan rate, size, and weight is assessed. The relative accuracies of the systems varied from <1% to approximately 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 to 210 s, as did the recovery time with a 6-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 ranged from 15 x 10(3) cm3 to 110 x 10(3) cm3. A performance scale is set up to rank each system, and an overall performance score is given to each system. PMID:12216728

  6. Interannual to decadal oxygen variability in the mid-depth water masses of the eastern North Atlantic

    NASA Astrophysics Data System (ADS)

    Stendardo, Ilaria; Kieke, Dagmar; Rhein, Monika; Gruber, Nicolas; Steinfeldt, Reiner

    2015-01-01

    The detection of multi-decadal trends in the oceanic oxygen content and its possible attribution to global warming is protracted by the presence of a substantial amount of interannual to decadal variability, which hitherto is poorly known and characterized. Here we address this gap by studying interannual to decadal changes of the oxygen concentration in the Subpolar Mode Water (SPMW), the Intermediate Water (IW) and the Mediterranean Outflow Water (MOW) in the eastern North Atlantic. We use data from a hydrographic section located in the eastern North Atlantic at about 48°N repeated 12 times over a period of 19 years from 1993 through 2011, with a nearly annual resolution up to 2005. Despite a substantial amount of year-to-year variability, we observe a long-term decrease in the oxygen concentration of all three water masses, with the largest changes occurring from 1993 to 2002. During that time period, the trends were mainly caused by a contraction of the subpolar gyre associated with a northwestward shift of the Subpolar Front (SPF) in the eastern North Atlantic. This caused SPMW to be ventilated at lighter densities and its original density range being invaded by subtropical waters with substantially lower oxygen concentrations. The contraction of the subpolar gyre reduced also the penetration of IW of subpolar origin into the region in favor of an increased northward transport of IW of subtropical origin, which is also lower in oxygen. The long-term oxygen changes in the MOW were mainly affected by the interplay between circulation and solubility changes. Besides the long-term signals, mesoscale variability leaves a substantial imprint as well, affecting the water column over at least the upper 1000 m and laterally by more than 400 km. Mesoscale eddies induced changes in the oxygen concentration of a magnitude that can substantially alias analyses of long-term changes based on repeat hydrographic data that are being collected at intervals of typically 10 years.

  7. 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.

  8. 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.

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

    NASA Technical Reports Server (NTRS)

    Pandit, Sudhakar M.

    1988-01-01

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

  10. 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.

  11. Grand challenges in mass storage: A systems integrators perspective

    NASA Technical Reports Server (NTRS)

    Lee, Richard R.; Mintz, Daniel G.

    1993-01-01

    Within today's much ballyhooed supercomputing environment, with its CFLOPS of CPU power, and Gigabit networks, there exists a major roadblock to computing success; that of Mass Storage. The solution to this mass storage problem is considered to be one of the 'Grand Challenges' facing the computer industry today, as well as long into the future. It has become obvious to us, as well as many others in the industry, that there is no clear single solution in sight. The Systems Integrator today is faced with a myriad of quandaries in approaching this challenge. He must first be innovative in approach, second choose hardware solutions that are volumetric efficient; high in signal bandwidth; available from multiple sources; competitively priced, and have forward growth extendibility. In addition he must also comply with a variety of mandated, and often conflicting software standards (GOSIP, POSIX, IEEE, MSRM 4.0, and others), and finally he must deliver a systems solution with the 'most bang for the buck' in terms of cost vs. performance factors. These quandaries challenge the Systems Integrator to 'push the envelope' in terms of his or her ingenuity and innovation on an almost daily basis. This dynamic is explored further, and an attempt to acquaint the audience with rational approaches to this 'Grand Challenge' is made.

  12. 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.

  13. 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.

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

    PubMed

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

    2007-10-01

    Matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) is emerging as a powerful tool for investigating the distribution of molecules within biological systems through the direct analysis of thin tissue sections. Unique among imaging methods, MALDI-IMS can determine the distribution of hundreds of unknown compounds in a single measurement. We discuss the current state of the art of MALDI-IMS along with some recent applications and technological developments that illustrate not only its current capabilities but also the future potential of the technique to provide a better understanding of the underlying molecular mechanisms of biological processes. PMID:17901873

  15. 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.

  16. 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.

  17. Variable Rate Irrigation Management for Humid Climates Using a Conventional Center Pivot System

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study investigates suitability of a standard commercial center pivot system for variable-rate water application under Mid-South conditions. The objective was to determine if field variability data can be applied to conventional moving sprinkler systems to optimize irrigation management on non-u...

  18. 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.

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

    NASA Astrophysics Data System (ADS)

    Yamada, Kazuo; Yoshimori, Akira

    2015-04-01

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

  20. 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.

  1. New low-cost metrology system for mass production

    NASA Astrophysics Data System (ADS)

    Blmel, Thomas; Bosse, Markus; Fehse, Jan; Gilliand, Yves; Kafka, Ricarda; Neubert, Ralph; Zellweger, Christian

    2008-03-01

    The mass production optic industry in many Asian countries frequently employs human inspection lines to assess the yield of their volume-produced optic components. The testing of shape and radius for the quality assessment of such lenses or prismatic elements of average accuracy specification is traditionally performed by using Fizeau interferometers for visual inspection. This method typically does not allow the documentation and/or printing of inspection reports due to the lack of cost-intensive computer and printer periphery. Increasing accuracy as well as the rising importance of quality assessment in mass production requires the elimination of human error as well as the documentation and statistical analysis of the inspection results. FISBA OPTIK developed the ?Phase (R) smartgage, a new stand-alone metrology system to address exactly this need. This instrument meets the major demands of the mass production for touch-of-a-button inspection, reliable pass/fail analysis, storage of measurement results and low investment costs. The compact unit is designed with the potential to replace visual human-inspection instruments for large-volume testing of relative shape accuracy and radius of curvature. The novel, small-footprint instrument is a stand-alone system with a fully integrated computing and display unit, sample alignment stage, touch-screen operation and optional connectivity for data export. This instrument offers simple, fast, reliable and vibration-insensitive measurement of shape deviation on flat and spherical optical components as well as relative radius of curvature. We present the measurement principle, the method of use and application, the measurement data presentation and data export capabilities. Application areas for the ?Phase (R) smartgage include testing of digital camera lenses, cell phone camera lenses, general purpose spherical lenses and flats of diameters up to one inch.

  2. A {approx} 40 YEAR VARIABILITY CYCLE IN THE LUMINOUS BLUE VARIABLE/WOLF-RAYET BINARY SYSTEM HD 5980?

    SciTech Connect

    Koenigsberger, Gloria; Hillier, D. John; Morrell, Nidia; Gamen, Roberto E-mail: georgiev@astro.unam.m E-mail: nmorrell@lco.c E-mail: rgamen@gmail.co

    2010-06-15

    The massive Wolf-Rayet stellar system HD 5980 in the Small Magellanic Cloud entered a sudden and brief {approx} 1-3 mag eruptive state in the mid-1990s. The cause of the instability is not yet understood, but mechanisms similar to those in luminous blue variables are suspected. Using a previously unreported set of spectroscopic data obtained in 1955-1967 and recently acquired optical and HST/STIS spectra, we find that (1) the brief eruptions of 1993 and 1994 occurred at the beginning of an extended ({approx} decades) high state of activity characterized by large emission-line intensities; (2) the level of activity is currently subsiding; and (3) another strong emission-line episode appears to have occurred between 1960 and 1965, suggesting the possibility that the long-term cyclical variability may be recurrent on a {approx} 40 year timescale. These characteristics suggest the possible classification of HD 5980 as an S Doradus-type variable. The effects due to binary interactions in the system are discussed, and we tentatively suggest that the short duration and relatively hot spectral type (WN11/B1.5I) observed during maximum in the visual light curve may be attributed to these interactions.

  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. 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.

  5. Experience with the UniTree mass storage system

    SciTech Connect

    Holmes, H.H.; Loken, S.

    1992-09-01

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

  6. 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.

  7. Multiresolution local binary pattern texture analysis combined with variable selection for application to false-positive reduction in computer-aided detection of breast masses on mammograms.

    PubMed

    Choi, Jae Young; Ro, Yong Man

    2012-11-01

    In this paper, a new and novel approach is designed for extracting local binary pattern (LBP) texture features from the computer-identified mass regions, aiming to reduce false-positive (FP) detection in a computerized mass detection framework. The proposed texture feature, the so-called multiresolution LBP feature, is well able to characterize the regional texture patterns of core and margin regions of a mass, as well as to preserve the spatial structure information of the mass. In addition, to maximize a complementary effect on improving classification accuracy, multiresolution texture analysis has been incorporated into the extraction of LBP features. Further, SVM-RFE-based variable selection strategy is applied for selecting an optimal subset of variables of multiresolution LBP texture features to maximize the separation between breast masses and normal tissues. Extensive and comparative experiments have been conducted to evaluate the proposed method on two public benchmark mammogram databases (DBs). Experimental results show that the proposed multiresolution LBP features (extracted from automatically segmented mass boundaries) outperform other state-of-the-art texture features developed for FP reduction. Our results also indicate that combining our multiresolution LBP features with variable selection strategy is an effective solution for reducing FP signals in computer-aided detection (CAD) of mammographic masses. PMID:23053352

  8. Multiresolution local binary pattern texture analysis combined with variable selection for application to false-positive reduction in computer-aided detection of breast masses on mammograms

    NASA Astrophysics Data System (ADS)

    Choi, Jae Young; Ro, Yong Man

    2012-11-01

    In this paper, a new and novel approach is designed for extracting local binary pattern (LBP) texture features from the computer-identified mass regions, aiming to reduce false-positive (FP) detection in a computerized mass detection framework. The proposed texture feature, the so-called multiresolution LBP feature, is well able to characterize the regional texture patterns of core and margin regions of a mass, as well as to preserve the spatial structure information of the mass. In addition, to maximize a complementary effect on improving classification accuracy, multiresolution texture analysis has been incorporated into the extraction of LBP features. Further, SVM-RFE-based variable selection strategy is applied for selecting an optimal subset of variables of multiresolution LBP texture features to maximize the separation between breast masses and normal tissues. Extensive and comparative experiments have been conducted to evaluate the proposed method on two public benchmark mammogram databases (DBs). Experimental results show that the proposed multiresolution LBP features (extracted from automatically segmented mass boundaries) outperform other state-of-the-art texture features developed for FP reduction. Our results also indicate that combining our multiresolution LBP features with variable selection strategy is an effective solution for reducing FP signals in computer-aided detection (CAD) of mammographic masses.

  9. Numerical Investigation of Multiple-, Interacting-Scale Variable-Density Ground Water Flow Systems

    NASA Astrophysics Data System (ADS)

    Cosler, D.; Ibaraki, M.

    2004-12-01

    The goal of our study is to elucidate the nonlinear processes that are important for multiple-, interacting-scale flow and solute transport in subsurface environments. In particular, we are focusing on the influence of small-scale instability development on variable-density ground water flow behavior in large-scale systems. Convective mixing caused by these instabilities may mix the fluids to a greater extent than would be the case with classical, Fickian dispersion. Most current numerical schemes for interpreting field-scale variable-density flow systems do not explicitly account for the complexities caused by small-scale instabilities and treat such processes as "lumped" Fickian dispersive mixing. Such approaches may greatly underestimate the mixing behavior and misrepresent the overall large-scale flow field dynamics. The specific objectives of our study are: (i) to develop an adaptive (spatial and temporal scales) three-dimensional numerical model that is fully capable of simulating field-scale variable-density flow systems with fine resolution (~1 cm); and (ii) to evaluate the importance of scale-dependent process interactions by performing a series of simulations on different problem scales ranging from laboratory experiments to field settings, including an aquifer storage and freshwater recovery (ASR) system similar to those planned for the Florida Everglades and in-situ contaminant remediation systems. We are examining (1) methods to create instabilities in field-scale systems, (2) porous media heterogeneity effects, and (3) the relation between heterogeneity characteristics (e.g., permeability variance and correlation length scales) and the mixing scales that develop for varying degrees of unstable stratification. Applications of our work include the design of new water supply and conservation measures (e.g., ASR systems), assessment of saltwater intrusion problems in coastal aquifers, and the design of in-situ remediation systems for aquifer restoration. We present preliminary model results for high-resolution simulation of variable-density flow and transport in homogeneous and heterogeneous porous media. We explicitly solve the three-dimensional advection equation using mass-conservative, flux-integral techniques and finite-volume formulations that provide unrestricted time-step capabilities similar to those associated with semi-Lagrangian methods. Our implementation of B. P. Leonard's MACHO (Multidimensional Advective-Conservative Hybrid Operator) and COSMIC (Conservative Operator Splitting for Multidimensions with Inherent Constancy) methods is an Nth-order (e.g., 7th-order or higher) advection scheme that significantly reduces numerical dispersion and can be adapted spatially and temporally as the simulation progresses. The ability of these higher-order methods to yield accurate, nonoscillatory concentration profiles is illustrated and compared to traditional implicit solution methods such as central and upwind differencing, and van Leer flux limiters. We also show preliminary results from our implementation of adaptive mesh refinement (AMR) techniques and discuss the interrelationship between AMR and the Nth-order advection schemes.

  10. 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.

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

    PubMed Central

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

    2013-01-01

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

  12. Infall variability in the Classical T Tauri system VZ Chamaeleonis

    NASA Astrophysics Data System (ADS)

    Smith, K.; Lewis, G. F.; Bonnell, I. A.; Emerson, J. P.

    2001-11-01

    We present time series spectroscopy of the Classical T Tauri star VZ Cha. We follow spectral variations at intermediate resolution over five successive nights, or approximately two rotation periods. We see profile features which persist on timescales longer than the expected infall time from the inner disc, and we see expected evidence of rotational variations in the lines, but we also note that rotation alone cannot produce all the observed variability and some other mechanism must be invoked. The behaviour of Hα is observed to be markedly different from that of the other lines. In particular, the evidence of rotational effects is lacking at Hα , and the activity in the red and blue wings of the line is not significantly correlated, in contrast to the other Balmer lines.

  13. Accurate mass filtering of ion chromatograms for metabolite identification using a unit mass resolution liquid chromatography/mass spectrometry system.

    PubMed

    Gu, Ming; Wang, Yongdong; Zhao, Xian-Guo; Gu, Zhe-Ming

    2006-01-01

    Acceleration of liquid chromatography/mass spectrometric (LC/MS) analysis for metabolite identification critically relies on effective data processing since the rate of data acquisition is much faster than the rate of data mining. The rapid and accurate identification of metabolite peaks from complex LC/MS data is a key component to speeding up the process. Current approaches routinely use selected ion chromatograms that can suffer severely from matrix effects. This paper describes a new method to automatically extract and filter metabolite-related information from LC/MS data obtained at unit mass resolution in the presence of complex biological matrices. This approach is illustrated by LC/MS analysis of the metabolites of verapamil from a rat microsome incubation spiked with biological matrix (bile). MS data were acquired in profile mode on a unit mass resolution triple-quadrupole instrument, externally calibrated using a unique procedure that corrects for both mass axis and mass spectral peak shape to facilitate metabolite identification with high mass accuracy. Through the double-filtering effects of accurate mass and isotope profile, conventional extracted ion chromatograms corresponding to the parent drug (verapamil at m/z 455), demethylated verapamil (m/z 441), and dealkylated verapamil (m/z 291), that contained substantial false-positive peaks, were simplified into chromatograms that are substantially free from matrix interferences. These filtered chromatograms approach what would have been obtained by using a radioactivity detector to detect radio-labeled metabolites of interest. PMID:16463359

  14. GENETIC VARIABILITY FOR EARLY SEASON ROOT SYSTEM DEVELOPMENT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The growth of the root system of cotton (Gossypium hirsutum L.) is under genetic control but may be modified by the environment. The early development of a vigorous root system is critical for obtaining an adequate stand for improved productivity. However, in many cases the soil temperatures at pl...

  15. Out of plane equilibrium points locations and the forbidden movement regions in the restricted three-body problem with variable mass

    NASA Astrophysics Data System (ADS)

    Abouelmagd, Elbaz I.; Mostafa, A.

    2015-05-01

    This work aims to present an analytical study on the dynamics of a third body in the restricted three-body problem. We study this model in the context of the third body having variable-mass changes according to Jeans' law. The equation of motion is constructed when the variation of the mass is non-isotropic. We find an appropriate approximation for the locations of the out-of-plane equilibrium points in the special case of a non-isotropic variation of the mass. Moreover, some graphical investigations are shown for the effects of the parameters which characterize the variable mass on the locations of the out-of-plane equilibrium points, the regions of possible and forbidden motions of the third body. This model has many applications, especially in the dynamics behavior of small objects such as cosmic dust and grains. It also has interesting applications for artificial satellites, future space colonization or even vehicles and spacecraft parking.

  16. 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.

  17. 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.

  18. Early Pleistocene short-term intermediate water mass variability influences Carbonate Mound development in the NE Atlantic (IODP Site 1317)

    NASA Astrophysics Data System (ADS)

    Raddatz, J.; Rüggeberg, A.; Margreth, S.; Liebetrau, V.; Dullo, W.; Eisenhauer, A.; Iodp Expedition 307 Scientific Party

    2010-12-01

    The Integrated Ocean Drilling Program (IODP) Exp. 307 drilled the 155 m high Challenger Mound in the Porcupine Seabight (SW off Ireland) in order to investigate for the first time sediments from the base of a giant carbonate mound. In this study we focus on sediments from the base of Challenger Mound (Porcupine Seabight, SW off Ireland) IODP Site 1317 in high resolution. The mound initiation and start-up phase coincides with the intensification of the Northern Hemisphere Glaciation (INHG) at around 2.6 Ma. Further carbonate mound development seems to be strongly dependent on rapid changes in paleoceanographic and climatic conditions at the Pliocene-Pleistocene boundary, especially characterized and caused by the interaction of intermediate water masses, the Mediterranean Outflow Water (MOW), the Eastern North Atlantic Water (ENAW) and the influence of Southern Component Water (SCW). This study is based on well-established proxies such as δ18O and δ13C of planktonic (Globigerina bulloides) and benthic foraminifera (Fontbotia wuellerstorfi, Discanomalina coronata, Lobatula lobatula, Lobatula antarctica, and Planulina ariminensis) as well as grain size parameters to identify the paleoenvironmental and paleoecological setting favourable for the initial coral colonization on the mound. Stable oxygen and carbon isotope records of benthic foraminiferal species indicate that L. lobatula provides a reliable isotopic signature for paleoenvironmental reconstructions. In particular, δ18O values of L. lobatula indicate initial mound growth started in a glacial mode with moderate excursions in δ18O values. Bottom water temperatures, calculated using standard equations based on δ18O of foraminiferal tests, range between 7 and 11°C, consistent with the known temperature range conducive for cold-water coral growth and development. Bottom currents transporting intermediate water masses of southern origin (Mediterranean, Bay of Biscay) enhanced at 2.6 Ma supporting first coral settlements with the INHG. The benthic δ13C and the sortable silt records indicate that the early Pleistocene hydrodynamic regime was characterized by weaker current intensities associated with vertical movements of MOW or its replacement by SCW at intermediate depth. After these sluggish phases enhanced MOW flow dominated again and led to stronger current intensities and most probably sediment erosion on Challenger Mound. Erosion in combination with early diagenetic (oxidation) processes overprinted the sediment layers as indicated by dissolved coral skeletons, the increase in Ca-content and sediment density, minimum δ13Cplanktonic values, as well as the occurrence of gypsum and pyrite, implying a careful evaluation of original and overprinted geochemical signals. We conclude that the Challenger Mound development was already influenced by short-term variability of water masses from southern origin and possible erosional events comparable to the late Pleistocene setting.

  19. 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.

  20. 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

  1. Zero and root loci of disturbed spring-mass systems.

    PubMed

    Lecomte, Christophe

    2014-04-01

    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

  2. Super Efimov effect for mass-imbalanced systems

    NASA Astrophysics Data System (ADS)

    Moroz, Sergej; Nishida, Yusuke

    2014-12-01

    We study two species of particles in two dimensions interacting by isotropic short-range potentials with the interspecies potential fine-tuned to a p -wave resonance. Their universal low-energy physics can be extracted by analyzing a properly constructed low-energy effective field theory with the renormalization group method. Consequently, a three-body system consisting of two particles of one species and one of the other is shown to exhibit the super Efimov effect, the emergence of an infinite tower of three-body bound states with orbital angular momentum ℓ =±1 whose binding energies obey a doubly exponential scaling, when the two particles are heavier than the other by a mass ratio greater than 4.034 04 for identical bosons and 2.414 21 for identical fermions. With increasing the mass ratio, the super Efimov spectrum becomes denser which would make its experimental observation easier. We also point out that the Born-Oppenheimer approximation is incapable of reproducing the super Efimov effect, the universal low-energy asymptotic scaling of the spectrum.

  3. GAMMA-RAY VARIABILITY FROM WIND CLUMPING IN HIGH-MASS X-RAY BINARIES WITH JETS

    SciTech Connect

    Owocki, S. P.; Townsend, R. H. D.; Romero, G. E.; Araudo, A. T.

    2009-05-01

    In the subclass of high-mass X-ray binaries known as 'microquasars', relativistic hadrons in the jets launched by the compact object can interact with cold protons from the star's radiatively driven wind, producing pions that then quickly decay into gamma rays. Since the resulting gamma-ray emissivity depends on the target density, the detection of rapid variability in microquasars with Gamma-Ray Large Area Space Telescope and the new generation of Cherenkov imaging arrays could be used to probe the clumped structure of the stellar wind. We show here that the fluctuation in gamma rays can be modeled using a 'porosity length' formalism, usually applied to characterize clumping effects. In particular, for a porosity length defined by h {identical_to} l/f, i.e., as the ratio of the characteristic size l of clumps to their volume filling factor f, we find that the relative fluctuation in gamma-ray emission in a binary with orbital separation a scales as {radical}(h/{pi}a) in the 'thin-jet' limit, and is reduced by a factor 1/{radical}(1 +{phi}a/2l) for a jet with a finite opening angle {phi}. For a thin jet and quite moderate porosity length h {approx} 0.03a, this implies a ca. 10% variation in the gamma-ray emission. Moreover, the illumination of individual large clumps might result in isolated flares, as has been recently observed in some massive gamma-ray binaries.

  4. 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.

  5. Molecular Insights into the Thermal Stability of mAbs with Variable-Temperature Ion-Mobility Mass Spectrometry.

    PubMed

    Pacholarz, Kamila J; Peters, Shirley J; Garlish, Rachel A; Henry, Alistair J; Taylor, Richard J; Humphreys, David P; Barran, Perdita E

    2016-01-01

    The aggregation of protein-based therapeutics such as monoclonal antibodies (mAbs) can affect the efficacy of the treatment and can even induce effects that are adverse to the patient. Protein engineering is used to shift the mAb away from an aggregation-prone state by increasing the thermodynamic stability of the native fold, which might in turn alter conformational flexibility. We have probed the thermal stability of three types of intact IgG molecules and two Fc-hinge fragments by using variable-temperature ion-mobility mass spectrometry (VT-IM-MS). We observed changes in the conformations of isolated proteins as a function of temperature (300-550 K). The observed differences in thermal stability between IgG subclasses can be rationalized in terms of changes to higher-order structural organization mitigated by the hinge region. VT-IM-MS provides insights into mAbs structural thermodynamics and is presented as a promising tool for thermal-stability studies for proteins of therapeutic interest. PMID:26534882

  6. 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.

  7. Design of variable frequency endoscope ultrasonic digital imaging system

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  8. Angular momentum and disk evolution in very low mass systems

    NASA Astrophysics Data System (ADS)

    Scholz, A.

    This review summarises recent observational results regarding the evolution of angular momentum and disks in brown dwarfs. The observations clearly show that brown dwarfs beyond ages of 10 Myr are exclusively fast rotators and do not spin down with age. This suggests that rotational braking by magnetic winds becomes very inefficient or ceases to work in the substellar regime. There is, however, some evidence for braking by disks during the first few Myrs in the evolution, similar to stars. Brown dwarf disks turn out to be scaled down versions of circumstellar disks, with dust settling, grain growth, and in some cases cleared out inner regions. The global disk properties roughly scale with central object mass. The evolutionary timescales in substellar disks are entirely consistent with what is found for stars, which may be challenging to understand. Given these findings, it is likely that brown dwarfs are able to form miniature planetary systems.

  9. 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.

  10. Physics design of fissile mass-flow monitoring system

    SciTech Connect

    Mattingly, J.K.; March-Leuba, J.; Valentine, T.E.; Mihalczo, J.T.; Uckan, T.

    1997-09-01

    The system measures the flow rate and uranium-235 content in liquid or gas streams; it does not penetrate the process piping. A moderated fission neutron source is used to periodicially introduce a burst of thermal neutrons into the fluid stream to induce fission; delayed gamma emissions from the resulting fission fragments are detected by high-efficiency scintillators downstream of the neutron source. The fluid flow rate is measure from the time between initiation of the thermal neutron burst and detection of the fission product gamma emissions, and the U-235 content is inferred from the intensity of the gamma burst detected. Design of the fissile mass flow monitor requires satisfaction of several competing constraints. Efficient operation of the monitor requires that source-induced fission rate and detection efficiency be maximized while the source-induced background rate is simultaneoulsy minimized. Near optical nuclear design of the system was achieved using numerous Monte Carlo calculations and measurements. This paper addresses calculational aspects of the physics design for the system applied to UF{sub 6} gas.

  11. Accelerator mass spectrometry with a coupled tandem-linac system

    SciTech Connect

    Kutschera, W.

    1984-01-01

    A coupled system provides higher energies, which allows one to extend AMS to hitherto untouched mass regions. Another important argument is that the complexity, although bothersome for the operation, increases the selectivity of detecting a particular isotope. The higher-energy argument holds for any heavy-ion accelerator which is capable of delivering higher energy than a tandem. The present use of tandem-linac combinations for AMS, rather than cyclotrons, linacs or combinations of these machines, has mainly to do with the fact that this technique was almost exclusively developed around tandem accelerators. Therefore the tandem-linac combination is a natural extension to higher energies. The use of negative ions has some particular advantages in suppressing background from unwanted elements that do not form stable negative ions (e.g., N, Mg, Ar). On the other hand, this limits the detection of isotopes to elements which do form negative ions. For particular problems it may therefore be advantageous to use a positive-ion machine. What really matters most for choosing one or the other machine is to what extent the entire accelerator system can be operated in a truly quantiative way from the ion source to the detection system. 20 references, 4 figures.

  12. 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.

  13. 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)

  14. 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.

  15. 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.

  16. Variable configuration fiber optic laser Doppler vibrometer system

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

    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.

  17. An Increase in the Mass of Planetary Systems around Lower-mass Stars

    NASA Astrophysics Data System (ADS)

    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⨁) than main-sequence FGK stars, but two times fewer Neptune-sized and larger (>2.8 R⨁) 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⨁ in F stars to 5 M⨁ in G and K stars to 7 M⨁ 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.

  18. Variable-rate irrigation management using an expert system in the eastern coastal plain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Variable rate irrigation (VRI) systems have the potential to conserve water by spatially allocating limited water resources. These water savings become more important as urban, industrial, and environmental sectors compete with agriculture for available water. In this study, we conducted variable ra...

  19. 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)…

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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. PMID:26259574

  5. 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.

  6. 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.

  7. 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.

  8. 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...

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

    PubMed Central

    Waterer, Grant W; Wunderink, Richard G

    2003-01-01

    The present review discusses recent studies that have identified genetic differences in inflammatory proteins associated with different phenotypic presentations of systemic inflammation. Basic genetic terminology is defined. Implications of genetic influences on the inflammatory response are discussed. The published associations of specific polymorphisms in antigen recognition pathways, proinflammatory cytokines, anti-inflammatory cytokines, and effector molecules are reviewed. The strongest and most consistent associations thus far have been with the tumor necrosis factor, lymphotoxin-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

  10. 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.

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

    NASA Astrophysics Data System (ADS)

    Meng, Yu; Chen, Hong; Chen, Cheng

    2015-03-01

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

  12. 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 high fluxes in the following cold La Niña phase. Bakun (1990) suggested an intensification of coastal upwelling due to increased winds ("Bakun upwelling intensification hypothesis", Cropper et al., 2014) and global change. We did not observe an increase of any flux component off Cape Blanc during the past two and a half decades which might support this hypothesis. Furthermore, fluxes of mineral dust did not show any positive or negative trends over time which would have suggested enhanced desertification or "Saharan greening" during the last few decades.

  13. Increased intraindividual reaction time variability in persons with neuropsychiatric manifestations of systemic lupus erythematosus.

    PubMed

    Haynes, Becky I; Bunce, David; Davies, Kevin A; Rusted, Jenifer M

    2015-05-01

    Systemic Lupus Erythematosus (SLE) can affect multiple organ systems, including the central (CNS) and/or peripheral nervous system. Individuals with nervous system involvement (termed Neuropsychiatric SLE or NPSLE) can present with nonspecific symptoms such as cognitive dysfunction. It is difficult to ascertain whether this is a direct consequence of lupus disease activity on the brain. Intraindividual variability, measured through trial-to-trial reaction time variation, has been proposed as a behavioral marker of CNS integrity. We compared 14 NPSLE, 20 non-NPSLE, and 27 age-matched healthy participants using multiple variability metrics. Variability was increased in NPSLE compared with non-NPSLE participants, and was increased throughout the distribution rather than there being a selective increase in extreme reaction times. Variability metrics were strongly intercorrelated providing convergent evidence that the different metrics are tapping similar processes. The results suggest that there is ongoing disruption to cognitive processing in NPSLE and may indicate small fluctuations in attention. PMID:25716749

  14. 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...

  15. 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.).

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

    PubMed

    Carreras, Nria; Alonso, Cristina; Mart, 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

  17. Cold Mass Support System for he D0 Solenoid

    SciTech Connect

    Squires, B.; /Fermilab

    1993-08-09

    The support system is designed to support the gravitational, magnetic, and thermal contraction loads associated with the cold mass weighing 1.46 metric tons (3210 Ibm). The loading constraints are listed in Table 1. The support system consists of axial members (axial supports) to provide longitudinal stiffness and nearly tangential members (radial supports) to provide radial stiffness. The members connect the outer support cylinder to the flat annular bulkheads of the vacuum vessel. See Figures 1 through 3 for additional details on the supports. Six axial compression-tension supports are located on the chimney end of the cryostat only. Six radial tension supports are located on each end. Both types of members are fabricated of Inconel 718 and have a design safety factor of 4 on the ultimate strength at 300 K. The axial supports are also designed for a buckling safety factor of 4 for the operating loads. Shipping stops will be installed to prevent the axial supports from going into compression during transportation. Axial and radial contraction of the coil support cylinder is accommodated by spherical bearings on both ends ofeach support member.

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

    SciTech Connect

    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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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. PMID:24652648

  7. 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.

  8. Mass Metrology and the International System of Units (SI)

    NASA Astrophysics Data System (ADS)

    Davis, Richard S.

    The International System of Units (SI) is widely used in science, industry, and commerce because it caters simultaneously to the needs of all. In the early twenty-first century, this means defining the units of time, length, mass, and electricity in terms of the fundamental constants of physics, and then "realizing" these definitions to sufficient accuracy on the human scale of the second, meter, kilogram, and ampere. This program has already been successful except for the kilogram, which is still defined in terms of an artifact constructed in the late nineteenth century. Although quantum-based electrical standards are widely used, the SI voltages or resistances produced by these standards depend on the values of constants that are at present based on experimental values derived from the artifact kilogram. This chapter presents the current state of affairs, which is unsatisfactory, and proceeds to describe work that will lead to a redefinition of the kilogram, probably in terms of a fixed value for the Planck constant.

  9. Isotope dilution mass spectrometry and the National Reference System.

    PubMed

    Bowers, G N; Fassett, J D; White, E

    1993-06-15

    The clinical laboratory community of the United States, which is well represented by the NRSCL/NCCLS, has endorsed the IDMS/DMs developed at NIST. These DMs provide the accuracy (true value) base for the U.S. National Reference System for a number of specific analytes in human serum. Fortunately, the U.S. government through (a) actions of NIST administrators and scientists, (b) financial support from NIH (NIGMS) and FDA, and (c) interagency agreements with CDC has accepted the responsibility for developing and maintaining IDMS/DMs for clinically important analytes as an essential part of this national measurement system infrastructure. Furthermore, it is important to note that several professional organizations, particularly, The American Association for Clinical Chemistry (AACC) and The College of American Pathologists (CAP), have interacted heavily with NIST in full support of these national standardization activities. CAP supports three full-time Research Associates at NIST so that target values on serum samples used in its Interlaboratory Comparison Survey Programs may be traced to DMs. This remarkable cooperation and teamwork between government agencies and private sector organizations, as well as numerous individual scientists and physicians, which promotes greater accuracy of patient results, depends heavily upon the continued timely availability of IDMS/DM measurements. In short, NIST's value assignments on human serum samples (e.g., SRMs and materials for CLIA '88 proficiency testing programs) by this critical IDMS/DM metrology provide the pragmatic base for assuring accurate test results in medicine. The resources required to support IDMS/DM technology at NIST over many decades are not trivial and from time to time require renewed R&D efforts to upgrade methodology and recapitalization in mass spectrometry instrumentation. PMID:8333621

  10. 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…

  11. Geochemical and Energetic Variability across Geothermal Systems in Yellowstone National Park (YNP)

    NASA Astrophysics Data System (ADS)

    Ackerman, G. G.; Macur, R. E.; Taylor, W. P.; Kozubal, M. A.; Korf, S.; Inskeep, W. P.

    2005-12-01

    The physical and chemical characteristics of geothermal outflow channels have been evaluated and correlated with microbial community structure within a variety of geothermal springs in Yellowstone National Park (YNP). Several high-temperature (75-90 C), low to near-neutral pH hot springs in YNP were characterized over a two-year period for a comprehensive understanding of the possible geochemical controls on resident chemolithotrophic microbial populations. Our goal was to analyze and compare YNP geothermal systems in terms of the free energy (Grxn) available from various exergonic oxidation/reduction (redox) reactions. Important electron donors in YNP geothermal systems were measured and include H2, H2S , S0, Fe2+, CH4, and NH4+; terminal electron acceptors of noted importance include O2, NO3-, Fe3+, , S0, SO42- and CO2. Thermodynamic modeling of aqueous chemical species was used to calculate the non-standard state free energy values for a variety of oxidation-reduction reactions potentially important for chemolithotrophic metabolism. Energetic profiles as a function of distance from spring source and temperature were calculated for a series of redox reactions in several YNP springs. Variable temperatures and reactant concentrations across several geothermal springs (pH ranges 2.5-6.8) generally did not significantly change the favorability of many of the reactions considered. These findings imply that observable changes in the distribution of microbial populations are likely linked to physical (e.g. mass transfer, temperature) and biological factors. There are, however, important comparisons to be made among exergonic reactions and presumed metabolisms of resident microbial populations. Both energetic and kinetic considerations will be necessary for understanding which oxidation-reduction reactions provide a competitive metabolic advantage to primary producers in geothermal springs.

  12. 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.

  13. Fronts, water masses and heat content variability in the Western Indian sector of the Southern Ocean during austral summer 2004

    NASA Astrophysics Data System (ADS)

    Anilkumar, N.; Luis, Alvarinho J.; Somayajulu, Y. K.; Ramesh Babu, V.; Dash, M. K.; Pednekar, S. M.; Babu, K. N.; Sudhakar, M.; Pandey, P. C.

    2006-11-01

    High density CTD and XBT sections were covered from 35 to 56S along 45E and 5730'E to investigate the morphology of the main fronts in the southwest Indian Ocean, as a part of the Indian pilot expedition to the Southern Ocean on board ORV Sagar Kanya. Northern branch of the Subtropical Front (NSTF) was observed at 3530'S along 45E. Along 5730'E, the signature of the Agulhas Return Front (ARF) + Subtropical Front (STF) was identified with a rapid decrease in surface temperature between 4330' and 45S and it is located with a southward shift compared to that at 45E. The Subantarctic Front (SAF) was distinguished as two fronts as northern SAF (SAF1) and southern SAF (SAF2) along both the meridional sections. Polar Front1 (PF1) was identified between 49 and 50S whereas Polar Front2 (PF2) was identified between 52 and 54S along 45E. This study reveals a southward shift of the oceanic fronts (ARF + STF) from west to east, with a maximum southward displacement of > 2 latitude at 5730'E. A novel finding of this study is that along 45E, SAF1 merged with ARF and SSTF and SAF2 4 latitude southwards from the merged fronts whereas along 5730'E, SAF1 was not identified as a merged front with ARF and STF as opposed to earlier studies [Belkin, I.M., Gordon, A.L., 1996. Southern Ocean fronts from the Greenwich Meridian to Tasmania. Journal of Geophysical Research 101, 3675-3696]. The thermocline region was absent south of PF. An enhancement in the mixed layer thickness from 42 to 52S occurred in association with the strengthening of the wind forcing. Major water masses like Subtropical Surface Water, Subantarctic Surface Water, Mode Water, Antarctic Intermediate Water, Circumpolar Deep Water and Antarctic Bottom Water were identified along 45E. Upper-ocean heat-content computation revealed a remarkable drop of 989 10 7 J m -2 at 42S and 1405 10 7 J m -2 at 44S along 45 and 5730'E, respectively. We believe that this sudden drop in heat content affects the meridional heat transfer which is crucial to the regional climatic variability.

  14. 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.

  15. Implementing RFID technology in a novel triage system during a simulated mass casualty situation.

    PubMed

    Jokela, Jorma; Simons, Tomi; Kuronen, Pentti; Tammela, Juha; Jalasvirta, Pertti; Nurmi, Jouni; Harkke, Ville; Castrén, Maaret

    2008-01-01

    The purpose of this study is to determine the applicability of Radio Frequency Identification (RFID) technology and commercial cellular networks to provide an online triage system for handling mass casualty situations. This was tested by a using a pilot system for a simulated mass casualty situation during a military field exercise. The system proved to be usable. Compared to the currently used system, it also dramatically improves the general view of mass casualty situations and enhances medical emergency readiness in a military medical setting. The system can also be adapted without any difficulties by the civilian sector for the management of mass casualty disasters. PMID:18583298

  16. 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

    2016-05-01

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

  17. [A Heart Rate Variability Analysis System for Short-term Applications].

    PubMed

    Shi, Bo; Chen, Fasheng; Zhang, Genxuan; Cao, Mingna; Tsau, Young

    2015-08-01

    In this paper, a heart rate variability analysis system is presented for short-term (5 min) applications, which is composed of an electrocardiogram signal acquisition unit and a heart rate variability analysis unit. The electrocardiogram signal acquisition unit adopts various digital technologies, including the low-gain amplifier, the high-resolution analog-digital converter, the real-time digital filter and wireless transmission etc. Meanwhile, it has the advantages of strong anti-interference capacity, small size, light weight, and good portability. The heart rate variability analysis unit is used to complete the R-wave detection and the analyses of time domain, frequency domain and nonlinear indexes, based on the Matlab Toolbox. The preliminary experiments demonstrated that the system was reliable, and could be applied to the heart rate variability analysis at resting, motion states etc. PMID:26710447

  18. 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 structure of the spacecraft as the launch vehicle's payload volume would allow when comparing mass savings verse the additional structure.

  19. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  1. Description and test results of a variable speed, constant frequency generating system

    NASA Astrophysics Data System (ADS)

    Brady, F. J.

    1985-12-01

    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.

  2. 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)…

  3. Factors Affecting Relationships between the Contextual Variables and the Information Characteristics of Accounting Information Systems.

    ERIC Educational Resources Information Center

    Choe, Jong-Min; Lee, Jinjoo

    1993-01-01

    Reports on a study of accounting information systems that explored the interactions among influence factors (e.g., user participation in the development process, top management support, capability of information systems personnel, and existence of steering committees), contextual variables (e.g., organizational structure and task characteristics),…

  4. 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...

  5. 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 ...

  6. Inclusive photoproduction of bottom quarks for low and medium pT in the general-mass variable-flavour-number scheme

    NASA Astrophysics Data System (ADS)

    Kramer, G.; Spiesberger, H.

    2016-02-01

    We present predictions for b-quark production in photoproduction and compare with experimental data from HERA. Our theoretical predictions are obtained at next-to-leading-order in the general-mass variable-flavor-number scheme, an approach which takes into account the finite mass of the b quarks. We use realistic evolved nonperturbative fragmentation functions obtained from fits to e+e- data. We find in general good agreement of data with both the GM-VFNS and the FFNS calculations, while the more precise ZEUS data seem to prefer the GM-VFNS predictions.

  7. Users guide for the shuttle mass properties automated system

    NASA Technical Reports Server (NTRS)

    Hamil, R. G.

    1975-01-01

    A set of programs developed for use on the JSC Univac 1100 series computers and designed to automate the collection and processing of data into the mass properties section of the shuttle operational data book is described.

  8. Erosion and voluminous mass movements during episodes of climate variability: landscape evolution in the southern-central Andes and the NW Himalaya. (Invited)

    NASA Astrophysics Data System (ADS)

    Strecker, M. R.; Bookhagen, B.

    2010-12-01

    Landscape morphology and sedimentary archives are recorders of climate change on different time scales. A better understanding of the nature of relatively fast changes in surface processes is becoming increasingly important, particularly in light of global warming and associated changes in geomorphic process rates. Catastrophic mass movements and extreme hydrologic events shape landscapes through a variety of processes that leave distinct sedimentologic and geomorphic signatures. This is certainly true in climatic threshold areas at high elevations that are very sensitive to the effects of climatic variability. Whereas recent low-frequency, high-magnitude hydrological events may be considered as important agents shaping landscapes in these environments, our understanding of the actual range of magnitudes is limited. The monsoonal domain in the NW Himalaya and the southern-central Andes of NW Argentina constitute an excellent natural laboratory to study the effects of climate variability and the effects of changing temperature and precipitation regimes on the surface process system. In the ENSO affected E flanks of the Puna Plateau of Argentina a large range of forcing magnitudes and geomorphic responses exists. Here, large amounts of sediments are transported from the hillslopes through debris flows and landslides and are eventually evacuated to the foreland. Voluminous landslide clusters associated with valley impoundment, the formation of transient lakes, and thick lacustrine sediment sequences during late Pleistocene and Holocene time were coeval with phases of increased precipitation and high lake levels during protracted paleo-ENSOs in the Altiplano-Puna, suggesting a causal relationship. Similarly, in the NW Himalaya increased landsliding activity followed insolation maxima in late Pleistocene and mid Holocene time coupled with intensified summer monsoons. In the Himalaya and the Andes these events also correlate with regionally recognized phases of increased humidity and increased erosion rates. Importantly, both areas show comparable behavior. In both areas landslide deposits typically overlie excavated valley bottoms and virtually never overlie multiple valley fills. Second, landsliding and the formation of intermontane lakes lagged behind the onset of a different climate mode. This suggests that a changeover to different climatic conditions may have been characterized by pronounced erosional processes, during which the trunk streams incised into alluvial fills and sediment was evacuated to the foreland. Subsequently, elevated pore pressures in tectonically overprinted basement rocks, and lateral fluvial scouring destabilized the slopes of the deeply incised ranges, thus increasing the likelihood for slope failure and deep-seated bedrock landslides. Taken together, elevated sediment transport rates during these times and the formation of landslide clusters in these environments emphasize the impact of climate variability on surface processes and landscape evolution and underscore the importance of large landslides in the sculpting of the topography of mountain belts.

  9. Accumulation Rate Variability and Winter Mass Balance Estimates using High Frequency Ground-Penetrating Radar and Snow Pit Stratigraphy on the Juneau Icefield, Alaska

    NASA Astrophysics Data System (ADS)

    Braddock, S. S.; Boucher, A. L.; Sandler, H. C.; McNeil, C.; Campbell, S. W.; Kreutz, K. J.

    2012-12-01

    In July 2012, 200 km of 400 MHz ground-penetrating radar (GPR) profiles were collected across the Juneau Icefield, Alaska. The goal was to determine if spatial accumulation rate variability and winter mass balance estimates could be improved by linking stratigraphic features between yearly-excavated snow pits through GPR. Profiles were collected along the centerline and cross sections of the main branch, northwest, and Southwest branch of the Taku Glacier as well as the Mathes, Llewellyn, and Demorest Glaciers. Over 650 km^2 of area and 1000 m of elevation range were covered during this pilot project linking sixteen snow pits with GPR data across the icefield. The field work was conducted as part of the Juneau Icefield Research Program (JIRP) with hopes of continuing this method in future years if first year results show promise. As an annually operated field research and education program, JIRP creates a unique opportunity to provide significant future contributions to Alaska mass balance records if the program is continued. Signal penetration reached ≤ 25 m with maximum depths reached at higher elevations of the icefield. Conversely, minimal penetration occurred in wetter regions at lower elevations, likely caused by volume scattering from free water within the firn and ice. Ice lenses and the annual layer located in mass balance snow pits correlated well with continuous stratigraphy imaged in GPR profiles suggesting that the lenses are relatively uninterrupted across the icefield and that GPR may be an appropriate tool for extrapolating point mass balance pit depths in this part of Alaska. The Northwest and Southwest Branches of the Taku Glacier show a strong stratigraphic thinning gradient, west to east; the main trunk of the Taku Glacier which originates from the Mathes-Llewellyn ice divide showed a similar thinning from the divide to the ELA. The thinning displayed by all three glacier systems matches a typical gradient from accumulation zone to ELA. However, it is also likely that a local influx of accumulation at the higher elevations of the Southwest and Northwest Branches result from their close proximity of the ocean. Beyond mass balance estimates, radar profiles also revealed ablation horizons underlying the annual layer near the ELA. Monitoring the location of this ablation horizon relative to the annual balance reflector may be helpful in quantifying changes in the ELA at the end of each previous melt season. Perched water tables were also imaged in several locations which may be suitable for future hydrological studies focused on delineation of sub-glacial drainage systems and their impact on local glacier dynamics. This is a particularly interesting finding considering the unprecedented recent jokulhlaup of the Mendenhall Glacier and re-routing of the primary water drainage at the Llewellyn Glacier terminus in 2011.

  10. 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.

  11. Ladder operators and associated algebra for position-dependent effective mass systems

    NASA Astrophysics Data System (ADS)

    Amir, Naila; Iqbal, Shahid

    2015-07-01

    An algebraic treatment of shape-invariant quantum-mechanical position-dependent effective mass systems is discussed. Using shape invariance, a general recipe for construction of ladder operators and associated algebraic structure of the pertaining system, is obtained. These operators are used to find exact solutions of general one-dimensional systems with spatially varying mass. We apply our formalism to specific translationally shape-invariant potentials having position-dependent effective mass.

  12. 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

  13. 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.

  14. Model-Driven Development of Decision Support Systems: Tackling the Variability Problem

    NASA Astrophysics Data System (ADS)

    Cabello, María Eugenia; Ramos, Isidro

    In this chapter, we present software variability management using conceptual models for diagnostic decision support information systems (DSS) development. We use a software product line (SPL) approach. In the construction of the SPL, two orthogonal variabilities are used to capture domain (i.e., diagnosis) and application domain (i.e., medical diagnosis) particularities. In this context, we describe how variability is managed by using our BOM (baseline-oriented modeling) approach. BOM is a framework that automatically generates applications as PRISMA software architectural models using model transformations and SPL techniques. We use model-driven architecture (MDA) to build domain models (i.e., computational-independent models, CIMs), which are automatically transformed into platform-independent models, PIMs, and then compiled to a executable application (i.e., platform-specific model, PSM). In order to illustrate BOM, we focus on a type of information system, the decision support system, specifically in the diagnostic domain.

  15. 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.

  16. Two-body coordinate system generation using body-fitted coordinate system and complex variable transformation. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Long, W. S.

    1977-01-01

    Attempts are made to generate acceptable coordinate systems for two-body configurations. The first method to be tried was to use the body-fitted coordinate system technique to obtain the best system. This technique alone did not produce very good results, so another approach was investigated. This new approach involved using a combination of the body fitted coordinate system procedure and a complex variable transformation method that was used successfully in conformal mapping.

  17. 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.

  18. Coping with Variability in Model-Based Systems Engineering: An Experience in Green Energy

    NASA Astrophysics Data System (ADS)

    Trujillo, Salvador; Garate, Jose Miguel; Lopez-Herrejon, Roberto Erick; Mendialdua, Xabier; Rosado, Albert; Egyed, Alexander; Krueger, Charles W.; de Sosa, Josune

    Model-Based Systems Engineering (MBSE) is an emerging engineering discipline whose driving motivation is to provide support throughout the entire system life cycle. MBSE not only addresses the engineering of software systems but also their interplay with physical systems. Quite frequently, successful systems need to be customized to cater for the concrete and specific needs of customers, end-users, and other stakeholders. To effectively meet this demand, it is vital to have in place mechanisms to cope with the variability, the capacity to change, that such customization requires. In this paper we describe our experience in modeling variability using SysML, a leading MBSE language, for developing a product line of wind turbine systems used for the generation of electricity.

  19. Design and fabrication of a basic mass analyzer and vacuum system

    NASA Technical Reports Server (NTRS)

    Judson, C. M.; Josias, C.; Lawrence, J. L., Jr.

    1977-01-01

    A two-inch hyperbolic rod quadrupole mass analyzer with a mass range of 400 to 200 amu and a sensitivity exceeding 100 packs per billion has been developed and tested. This analyzer is the basic hardware portion of a microprocessor-controlled quadrupole mass spectrometer for a Gas Analysis and Detection System (GADS). The development and testing of the hyperbolic-rod quadrupole mass spectrometer and associated hardware are described in detail.

  20. Development of a Rotating Test Mass System for Exotic Spin-Dependent Force Searches

    NASA Astrophysics Data System (ADS)

    Bohorquez, Juan; Snow, W. M.; Smith, Erick; Briggs, Ben; Din, Asiyah

    2015-10-01

    Theories of Physics beyond the Standard Model predict the possibility of a spin-dependent macroscopic force between spin polarized masses and unpolarized masses proportional to \\Scirc. \\rcirc. Previous experiments which bring a non-polarized mass near a polarized mass, and search for NMR frequency shifts have set the best limits on monopole-dipole interactions with matter at distances of one hundred hundred microns to 1 cm. We plan to improve the constraints on these interactions using a spinning test mass near an ensemble of rotating polarized spins produced in a newly-developed spin exchange optical pumping technique. The frequency and phase of the spinning test mass will be chosen to resonantly couple energy into the spin system if there is a monopole-dipole interaction. I will present the designs of the mechanical system that will hold the test mass and the control system that will rotate it at the required rate. Supported by NSF Grant PHY-1460882.