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1

Dynamics of Variable Mass Systems  

NASA Technical Reports Server (NTRS)

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.

Eke, Fidelis O.

1998-01-01

2

New kinetic energy operator for variable mass systems  

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

3

Mass-variable TLD systems and their seismic performance  

NASA Astrophysics Data System (ADS)

A conventional tuned liquid damper (TLD) generates a relatively small control force associated with low density of sloshing water. To overcome this main drawback, proposed in this study is a new TLD system composed of water and fine particles in a rectangular tank of sloping bottom. The effectiveness of the proposed mass-variable TLD system was demonstrated with shake table tests. In comparison with a conventional TLD, the mass-variable TLD can more effectively reduce structural responses particularly under large external excitations. The mass-variable TLD can also be effective in the earlier stage of an earthquake event due to the increasing mass nature as the excitation increases. This attribute makes the new TLD particularly attractive under impulsive loads such as near-field ground motions.

Xin, Yuxiang; Chen, Genda

2007-05-01

4

Dynamic analysis of a variable-mass multibody system  

NASA Astrophysics Data System (ADS)

A formulation of the equations of motion for variable mass, multibody system is presented. Based on this formulation, a computer program was developed to numerically simulate the motion of a given mechanical system. Captured or released material is modelled as a finite number of particle masses which can be entering or leaving the system at any number of locations. As demonstrated by an example, a continuous mass transfer process can be simulated quite accurately by increasing the number and decreasing the size of these particles. With this unique modelling procedure, the program is capable of analyzing systems undergoing quite general mass capture or release processes. The range of physical systems which can be analyzed by the program is limited to those with a specific topology.

McPhee, John J.; Dubey, Rajendra N.

1991-05-01

5

Dark Matter with Variable Masses  

Microsoft Academic Search

String effective theories contain a dilaton scalar field which couples to gravity, matter and radiation. In general, particle masses will have different dilaton couplings. We can always choose a conformal frame in which baryons have constant masses while (non-baryonic) dark matter have variable masses, in the context of a scalar-tensor grav- ity theory. We are interested in the phenomenology of

Juan Garc ´ õa-Bellido

6

Dark Matter with Variable Masses  

Microsoft Academic Search

String effective theories contain a dilaton scalar field which couples to gravity, matter and radiation. In general, particle masses will have different dilaton couplings. We can always choose a conformal frame in which baryons have constant masses while (nonbaryonic) dark matter have variable masses, in the context of a scalar-tensor gravity theory. We are interested in the phenomenology of this

Juan García-Bellido

1993-01-01

7

Two bodies gravitational systems with variable mass and damping-antidamping effect due to star wind  

NASA Astrophysics Data System (ADS)

We study two-bodies gravitational problem where the mass of one of the bodies varies and suffers a damping-anti damping effect due to star wind during its motion. A constant of motion, a Lagrangian and a Hamiltonian are given for the radial motion of the system, and the period of the body is studied using the constant of motion of the system. An application to the comet motion is given, using the comet Halley as an example.

Lopez Velazquez, Gustavo; Juarez, Esmeralda

2013-04-01

8

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

NASA Astrophysics Data System (ADS)

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.

Bettadpur, S.

2012-04-01

9

Mass transfer cycles in cataclysmic variables  

NASA Technical Reports Server (NTRS)

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.

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

1995-01-01

10

Movement Of a Body With Variable Mass  

NASA Astrophysics Data System (ADS)

In this paper we consider moving bodies with variable mass. Such kind of motion often occurs in nature and technology. We derived an equation of motion of bodies with variable mass in general case and by the example of rocket motion. Basic and some specific equations are given to describe such movement.

Samardzija, B.; Segan, S.

2012-12-01

11

Some useful properties of a theory of variable mass particles  

Microsoft Academic Search

By a simple extension of the canonical formalism, one can include mass and proper time as dynamical variables in mechanics. Such a theory allows one to treat particles with variable mass and also classically decaying particles. The theory has other properties which offer a fresh approach to classical dynamics. For example, the inertia of a system becomes an active concept,

Daniel M. Greenberger

1974-01-01

12

Population Synthesis Studies of Close Binary Systems Using a Variable Common Envelope Efficiency Parameter. I. Dependence on Secondary Mass  

NASA Astrophysics Data System (ADS)

We perform population synthesis calculations of present-day post-CE binaries (PCEBs) and zero-age cataclysmic variables (ZACVs) using a common envelope (CE) efficiency parameter, ?CE, that is a function of secondary mass, Ms. We investigate three basic possibilities: (1) a standard constant ?CE prescription, with ?CE ranging from 0.05 to 1.0, to provide a baseline for comparison; (2) a power-law dependence, ?CE=(Ms)n, with n=0.5, 1.0, and 2.0; and (3) a dependence in which ?CE approaches 1 for large Ms and ?CE=0 below some assumed cutoff mass, ?CE=1-Mcut/Ms, where Mcut=0.0375, 0.075, and 0.15 Msolar. We find that if ?CE<~0.2 in our constant ?CE sequence, the predicted present-day ZACV population is significantly modified compared with our standard model (?CE=1.0). All prior population synthesis calculations of the formation of CVs only considered values of ?CE>=0.3 and found that their model populations were not strongly dependent upon the value of ?CE. Our results indicate that a much wider range of values for ?CE, including very low values, must be considered in order for a dependence to be seen. In our variable ?CE sequences for ZACVs, we find that for models in which ?CE decreases very rapidly for small Ms, the orbital period distribution below the period gap differs significantly from our standard model. In particular, the fraction of CVs forming with P<2 hr is reduced significantly, the fraction forming in the gap is increased significantly, and both the short-period peak and the minimum period shift to considerably longer periods compared with our standard model. We suggest that the observed scarcity of CVs with P<77 minutes may possibly provide evidence that progenitor binaries with Ms<~0.10 Msolar are unable to avoid merger within the CE. We also suggest that if ?CE decreases rapidly for small Ms, it is possible that the lower edge of the period gap could be, in part, an imprint of the ZACV population.

Politano, Michael; Weiler, Kevin P.

2007-08-01

13

The white dwarf masses in cataclysmic variables  

NASA Astrophysics Data System (ADS)

The mechanism proposed by Hameury et al. (1988) for the 114-min periodicity in 6 of the 13 known AM Her magnetic cataclysmic variables (MCVs) is examined in the light of published observational data on EXO 033319-2554.2, a newly discovered 126-min-period MCV (Giommi et al., 1987; Beuermann and Thomas, 1987). The techniques used to estimate the masses of the white-dwarf primaries in MCVs are discussed, and it is concluded that the mass of EXO 033319-2554.2 is significantly greater (by 0.25-0.60 solar mass) than that in the MCVs with 114-min periodicity.

Hameury, J. M.; Lasota, J. P.; King, A. R.

1988-04-01

14

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

PubMed

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

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

2013-10-01

15

Variable contour securing system  

NASA Technical Reports Server (NTRS)

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

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

1978-01-01

16

Climate warming increases Greenland Ice Sheet surface mass balance variability  

NASA Astrophysics Data System (ADS)

We analyze Greenland Ice Sheet (GIS) surface mass balance (SMB) trends generated by the Community Earth System Model for the time period 1850-2100. In addition to the expected decrease in the mean SMB, our analysis reveals a significant secular increase in temporal, integrated SMB variability. The largest variability increase occurs during the 21st century, and arises primarily from growth of the GIS ablation zone (i.e., a decrease in the accumulation area ratio, AAR) in conjunction with a high ratio of ablation-zone to accumulation-zone specific SMB variability. A secondary cause of the overall variability increase is a rise in specific SMB variability itself in both the accumulation and ablation zones, due to increased accumulation variability and lengthened melt seasons. Simple sensitivity experiments indicate that neither mechanism (decrease in the AAR, and increased specific SMB variability) in isolation is capable of causing the overall increase in integrated SMB variability. However, by exposing more of the ice sheet to high-variability ablation, the decrease in the AAR is about twice as effective as increased specific SMB variability in causing the overall variability increase. Ablation-zone SMB variability is driven largely by variability in summertime melting which is in turn regulated by variability in summertime surface energy fluxes. Broader climate processes that regulate these fluxes will therefore exert increasing control on GIS SMB variability in the future. This future increase in SMB variability can be expected to impact GIS-sourced freshwater fluxes and GIS ice dynamic variability, and may also make it more difficult to diagnose future secular trends in GIS volume.

Fyke, J. G.; Vizcaino, M.; Lipscomb, W. H.; Sacks, W.

2013-12-01

17

Mass Storage Systems.  

ERIC Educational Resources Information Center

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

Ranade, Sanjay; Schraeder, Jeff

1991-01-01

18

Ultra High Mass Range Mass Spectrometer System  

DOEpatents

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.

Reilly, Peter T. A. [Knoxville, TN

2005-12-06

19

Investigation of the three-body-points problem with variable masses using the analytical calculation system ``Mathematica": Theory  

NASA Astrophysics Data System (ADS)

The equations of motion of the investigated problem are obtained in the osculating elements of an aperiodic motion at the quasiconic section. Secular parts of the perturbing functions are calculated in terms of the osculating canonical elements with the use of the system ``Mathematica". Full first-order secular perturbations are obtained by the method of Picard.

Minglibayev, M. Zh.; Mayemerova, G. M.

2013-08-01

20

Mode Selection Techniques in Variable Mass Flexible Body Modeling  

NASA Technical Reports Server (NTRS)

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.

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

2010-01-01

21

Modeling and Simulation of Variable Mass, Flexible Structures  

NASA Technical Reports Server (NTRS)

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,

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

2009-01-01

22

Binary mass ratios: system mass not primary mass  

NASA Astrophysics Data System (ADS)

Binary properties are usually expressed (for good observational reasons) as a function of primary mass. It has been found that the distribution of companion masses - the mass ratio distribution - is different for different primary masses. We argue that system mass is the more fundamental physical parameter to use. We show that if system masses are drawn from a log-normal mass function, then the different observed mass ratio distributions as a function of primary mass, from M-dwarfs to A-stars, are all consistent with a universal, flat, system mass ratio distribution. We also show that the brown dwarf mass ratio distribution is not drawn from the same flat distribution, suggesting that the process which decides upon mass ratios is very different in brown dwarfs and stars.

Goodwin, Simon P.

2013-03-01

23

Mass balance calculations with end member compositional variability: applications to petrologic problems  

Microsoft Academic Search

Although end member compositional variability is quite common, most quantitative mass balance procedures cannot accommodate this variability in a systematic manner. By rearranging the traditional mass balance relations, a series of equations can be derived to account for such heterogeneity. While this approach can be applied to n-component systems, the results are difficult to represent graphically. Accordingly, the procedure is

James D. Myers; Charles L. Angevine; Carol D. Frost

1987-01-01

24

Theory of Particles with Variable Mass. II. Some Physical Consequences  

Microsoft Academic Search

The formalism of the previous paper, in which mass and proper time are treated as independent dynamical variables in a canonical formalism, is shown to imply certain physical consequences. There will exist a mass vs proper time uncertainty relation; trajectories and proper time will be exactly determinable in an external gravitational field, while mass will be determinable in an external

Daniel M. Greenberger

1970-01-01

25

Variable mass unites Newtonian and GR gravity  

NASA Astrophysics Data System (ADS)

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/? ? (1+GM/rc^2), it follows that a rest mass, m0 in gravity-free space, increases to m^*=? m_0/? =m_0/?^2 under free fall. This increase of mass results in a real contraction of the metric of length and time intervals: l^*=?^2 l and t^*=?^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.

Collins, Russell

2000-03-01

26

Variability in properties of Salado Mass Concrete.  

National Technical Information Service (NTIS)

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...

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

1995-01-01

27

THE ENIGMATIC YOUNG, LOW-MASS VARIABLE TWA 30  

SciTech Connect

TWA 30 is a remarkable young (7 {+-} 3 Myr), low-mass (0.12 {+-} 0.04 M{sub sun}), late-type star (M5 {+-} 1) residing 42 {+-} 2 pc away from the Sun in the TW Hydrae Association (TWA). It shows strong outflow spectral signatures such as [S II], [O I], [O II], [O III], and Mg I], while exhibiting weak H{alpha} emission (-6.8 {+-} 1.2 A). Emission lines of [S II] and [O I] are common to T Tauri stars still residing in their natal molecular clouds, while [O III] and Mg I] emission lines are incredibly rare in this same population; in the case of TWA 30, these latter lines may arise from new outflow material colliding into older outflow fronts. The weak H{alpha} emission and small radial velocity shifts of line emission relative to the stellar frame of rest (generally {approx_lt}10 km s{sup -1}) suggest that the disk is viewed close to edge-on and that the stellar axis may be inclined to the disk, similar to the AA Tau system, based on its temporal changes in emission/absorption line strengths/profiles and variable reddening (A{sub V} = 1.5-9.0). The strong Li absorption (0.61 {+-} 0.13 A) and common kinematics with members of the TWA confirm its age and membership to the association. Given the properties of this system such as its proximity, low mass, remarkable outflow signatures, variability, and edge-on configuration, this system is a unique case study at a critical time in disk evolution and planet-building processes.

Looper, Dagny L.; Rayner, John; Pitts, Mark A. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Mohanty, Subhanjoy [Imperial College London, 1010 Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Bochanski, John J.; Burgasser, Adam J. [MIT Kavli Institute for Astrophysics and Space Research, 77 Massachusetts Avenue, Building 37-664B, Cambridge, MA 02139 (United States); Mamajek, Eric E. [Department of Physics and Astronomy, University of Rochester, P.O. Box 270171, 500 Wilson Boulevard, Rochester, NY 14627-0171 (United States); Herczeg, Gregory J. [Max-Planck-Institut fuer extraterrestriche Physik, Giessenbachstrase, 85748 Garching (Germany); West, Andrew A. [Department of Astronomy, Boston University, 725 Commonwealth Avenue, Boston, MA 02215 (United States); Faherty, Jacqueline K. [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 (United States); Kirkpatrick, J. Davy, E-mail: dagny@ifa.hawaii.ed [Infrared Processing and Analysis Center, MS 100-22, California Institute of Technology, Pasadena, CA 91125 (United States)

2010-05-01

28

Mass Storage System Reference Model System Management.  

National Technical Information Service (NTIS)

System Management is the collection of functions that are primarily concerned with the control, performance and utilization of the Mass Storage System defined by the Mass Storage System Reference Model. These functions are often very site-dependent, invol...

B. Collins T. McLarty

1988-01-01

29

Infrared Properties of Cataclysmic Variables from 2MASS  

NASA Astrophysics Data System (ADS)

Relatively little is known about the infrared (IR) properties of cataclysmic variables (CVs). Fortunately, advances in IR detector technology have recently made this region of the spectrum much more accessible. Investigating CVs in the IR wavelength regime contributes to our understanding of the properties of key system components that radiate strongly at wavelengths longer than the optical: the cool outer disk, accretion stream, and the secondary star. The Two Micron All Sky Survey (2MASS) is an ongoing project with the goal of imaging the entire sky down to completeness limits of J=15.8, H=15.1, and K=14.3 mag. We present here a preliminary look at the group IR properties of the ?500 CVs included in the 2MASS Second Incremental Data Release (March 2000) via IR color-color and color-magnitude diagrams. We will also provide a comparison of the homogenous 2MASS JHK magnitudes of these CVs with other published IR magnitudes (where available). The final product of this project (currently in preparation) will incorporate an IR atlas and catalog of all CVs detected by 2MASS. This catalog will contain a detailed analysis of their group IR properties as well as IR magnitudes and finding charts (and is intended as a companion resource to the invaluable optical CV catalogs of Downes & Shara and Downes et al.). This research makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center, funded by the National Aeronautics and Space Administration and the National Science Foundation.

Clark, L. L.; Wachter, S.; Hoard, D. W.; Bowers, T.

2000-12-01

30

Mass storage system reference model system management  

SciTech Connect

System Management is the collection of functions that are primarily concerned with the control, performance and utilization of the Mass Storage System defined by the Mass Storage System Reference Model. These functions are often very site-dependent, involve human decision making, and span multiple ''severs'' of the Mass Storage System. The functions may be implemented as standalone programs, may be integrated with the other Mass Storage System software, or may just be policy. 4 refs.

Collins, B.; McLarty, T.

1988-01-01

31

Modes, masses, metallicities, and magnitudes of RR Lyrae variables  

SciTech Connect

The author reviews past and recent developments in the study of RR Lyrae variables. He provides supporting evidence for a large helium content but remains uncertain as to their masses and luminosities. Time dependent convection is offered as a probable explanation for the double mode pulsations of these stars. 25 refs., 8 figs., 3 tabs.

Cox, A.N.

1987-07-01

32

Mass properties measurement system dynamics  

NASA Technical Reports Server (NTRS)

The MPMS mechanism possess two revolute degrees-of-freedom and allows the user to measure the mass, center of gravity, and the inertia tensor of an unknown mass. The dynamics of the Mass Properties Measurement System (MPMS) from the Lagrangian approach to illustrate the dependency of the motion on the unknown parameters.

Doty, Keith L.

1993-01-01

33

Outbursts by low-mass white dwarfs in symbiotic variables  

NASA Technical Reports Server (NTRS)

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.

Sion, Edward M.; Ready, Christian J.

1992-01-01

34

Applied eyewitness-testimony research: System variables and estimator variables  

Microsoft Academic Search

Proposes a distinction between 2 types of applied eyewitness-testimony research: System-variable (SV) research investigates varibles that are manipulable in actual criminal cases (e.g., the structure of a lineup) and, thus, has the potential for reducing the inaccuracies of eyewitnesses; estimator-variable (EV) research, however, investigates variables that cannot be controlled in actual criminal cases (e.g., characteristics of the witness) and, thus,

Gary L. Wells

1978-01-01

35

Variable frequency microwave furnace system  

DOEpatents

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.

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

1994-06-14

36

Variable frequency microwave furnace system  

DOEpatents

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).

Bible, Don W. (Clinton, TN); Lauf, Robert J. (Oak Ridge, TN)

1994-01-01

37

On The Pulsation Modes And Masses Of Osarg Variables  

NASA Astrophysics Data System (ADS)

OSARG(OGLE Small Amplitude Red Giants) are red giant (RGB/AGB) variables found in LMC/SMC and our Galactic bulge. By comparing the period-luminosity relations of LMC OSARG with calculated pulsation periods, we have found that various pulsation modes should be excited in OSARG; radial 1st, 2nd and 3rd overtone, and non-radial p1, p2 and p3 modes of l=2. In addition, we have found that the masses of RGB OSARG are in a range of 0.9 <= M/Msun < =1.4, while AGB OSARG have masses between 1 and 2.5 M/Msun. The AGB OSARG are still in early AGB stages and would be progenitors of Mira/Semi-regular variables. This work is supported by the Brain Circulation Program (R2301) by Japan Society for the Promotion of Science.

Takayama, Masaki; Saio, H.; Ita, Y.

2012-05-01

38

Water mass and throughflow transport variability in the Taiwan Strait  

Microsoft Academic Search

Variability of water mass and throughflow transport in the Taiwan Strait are analyzed using strait-wide conductivity-temperature-depth (1985–2003) and sectional acoustic Doppler current profiler (1999–2001) data. Results from a cluster analysis, temperature-salinity diagrams, and direct transport calculations indicate that the strong northeast monsoon drives the brackish Mixed China Coastal Water into the northern strait and hinders the northward intruded saline Kuroshio

Sen Jan; David D. Sheu; Huei-Ming Kuo

2006-01-01

39

Guide to transverse projections and mass-constraining variables  

SciTech Connect

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.

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

2011-11-01

40

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

NASA Technical Reports Server (NTRS)

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.

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

2008-01-01

41

Variable friction pendulum system for seismic isolation of liquid storage tanks  

Microsoft Academic Search

Earthquake response of liquid storage steel tanks isolated with variable friction pendulum system (VFPS) is investigated under normal component of six recorded near-fault ground motions. The continuous liquid mass of the tank is modeled as lumped masses known as sloshing mass, impulsive mass and rigid mass. The corresponding stiffness constants associated with these lumped masses are worked out depending upon

V. R. Panchal; R. S. Jangid

2008-01-01

42

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

NASA Technical Reports Server (NTRS)

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.

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

1983-01-01

43

Long-term variability of low-mass X-ray binaries  

NASA Astrophysics Data System (ADS)

We consider modulations of mass captured by the compact object from the companion star's stellar wind in Low Mass X-ray Binaries with late type giants. Based on 3D simulations with two different hydrodynamic codes used Lagrangian and Eulerian approaches - the SPH code GADGET and the Eulerian code PLUTO, we conclude that a hydrodynamical interaction of the wind matter within a binary system even without eccentricity results in variability of the mass accretion rate with characteristic time-scales close to the orbital period. Observational appearances of this wind might be similar to that of an accretion disc corona/wind.

Filippova, E.; Revnivtsev, M.; Parkin, E. R.

2014-01-01

44

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

SciTech Connect

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

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

2007-10-12

45

Equilibrium and nonequilibrium relativistic kinetic theory of particles with variable masses  

NASA Astrophysics Data System (ADS)

Relativistic kinetic theory is used to study a system in which the particles have variable rest masses due either to inelastic collisions between the particles or to an exchange of matter between the particles and an external gas. The thermodynamic properties of the system both at equilibrium and at small departures from equilibrium are investigated. The relativistic relaxation time model of Anderson and Witting (1974) is used to determine the transport coefficients.

Barrabes, C.

1982-03-01

46

Masses and radii for thirteen chromospherically active ellipsoidal variables  

NASA Technical Reports Server (NTRS)

The amplitude of the ellipticity effect, the mass function, and the V sin i in ten long-period RS CVn SB1 binaries are used to compute limits on the masses of the two stars and the radius of the primary: zeta And, UV CrB, V1764 Cyg, V826 Her, V350 Lac, GX Lib, V1197 Ori, AP Psc, 33 Psc, and EE UMa. Explicit masses and radii are computed for three SB2 systems: BL CVn, V1817 Cyg, and TZ Tri. The primary in several is found to fill 95 percent or more of its Roche lobe. The two minima produced by the ellipticity effect are unequal in depth, with the effect largest when i is near 90 deg and the primary nearly fills its Roche lobe. The greatest inequality found, in UV CrB, was 0.08 mag.

Hall, Douglas S.

1990-01-01

47

Masses and radii for thirteen chromospherically active ellipsoidal variables  

SciTech Connect

The amplitude of the ellipticity effect, the mass function, and the V sin i in ten long-period RS CVn SB1 binaries are used to compute limits on the masses of the two stars and the radius of the primary: zeta And, UV CrB, V1764 Cyg, V826 Her, V350 Lac, GX Lib, V1197 Ori, AP Psc, 33 Psc, and EE UMa. Explicit masses and radii are computed for three SB2 systems: BL CVn, V1817 Cyg, and TZ Tri. The primary in several is found to fill 95 percent or more of its Roche lobe. The two minima produced by the ellipticity effect are unequal in depth, with the effect largest when i is near 90 deg and the primary nearly fills its Roche lobe. The greatest inequality found, in UV CrB, was 0.08 mag. 31 refs.

Hall, D.S. (Tennessee State Univ., Nashville (USA))

1990-08-01

48

Influence of meteorological variability upon aerosol mass size distribution  

NASA Astrophysics Data System (ADS)

Aerosol mass size distribution has been measured by using an optical particle counter. The measurements were done in an urban background location in the western Mediterranean during winter 2006. The study has been focused in determining the mass size distribution under special meteorological conditions like moderate rain, considerable winds and high atmospheric stability. The results obtained showed a mass predominance of accumulation mode during rain and high stability periods although for different reasons. In the case of rain, it is due to greater atmospheric cleansing effectiveness that rain has upon coarse mode particles. However, during stagnant periods, the meteorological situation favored coagulation processes among nucleation mode particles giving like result a mass increase in the accumulation mode. Finally, strong winds favor the resuspension of the largest particles and the dispersion of particles with sizes inferior to 7.5 ?m. Similar results have been reproduced using principal component analysis (PCA). In this way, three components were identified. The first (PC1) represents particles in the accumulation mode. The second component (PC2) is constituted by coarse particles to 7.5 ?m, and the third (PC3) corresponds to coarser particles. The contribution of each group to the overall average concentration was determined: 27.2% corresponds to particles with sizes belonging within the first component, 35.4% to PC2 and 37.3% to PC3. Important percentage variability for each component under meteorological episodes has been obtained. Results obtained showed an important increase of PC1 during Rainy Days (53.8%) and High Pollution Days (40.2%). Contrary to this on Windy Days this component decreases to 7.4%. However, during this kind of day PC3 increases to 64.6%.

Nicolás, J. F.; Yubero, E.; Pastor, C.; Crespo, J.; Carratalá, A.

2009-10-01

49

Vehicular Variable-Parameter METRRA System.  

National Technical Information Service (NTIS)

The report and instruction manual is intended to describe the Variable Parameter Metal Re-Radiating Radar (METRRA) System (hereafter designated as the VP METRRA), depict its performance, and provide operating and maintenance instructions. A METRRA system ...

R. F. Elsner

1974-01-01

50

Interannual Variability of Patterns of Atmospheric Mass Distribution.  

NASA Astrophysics Data System (ADS)

Using the 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40) for 1958 to 2001, adjusted for bias over the southern oceans prior to 1979, an analysis is made of global patterns of monthly mean anomalies of atmospheric mass, which is approximately conserved globally. It differs from previous analyses of atmospheric circulation by effectively area weighting surface or sea level pressure that diminishes the role of high latitudes. To examine whether global patterns of behavior exist requires analysis of all seasons together (as opposite seasons occur in each hemisphere). Empirical orthogonal function (EOF) analysis, R-mode varimax-rotated EOF analysis, and cyclostationary EOF (CSEOF) analysis tools are used to explore patterns and variability on interannual and longer time scales. Clarification is given of varimax terminology and procedures that have been previously misinterpreted. The dominant global monthly variability overall is associated with the Southern Hemisphere annular mode (SAM), which is active in all months of the year. However, it is not very coherent from month to month and exhibits a great deal of natural unforced variability. The third most important pattern is the Northern Hemisphere annular mode (NAM) and associated North Atlantic Oscillation (NAO), which is the equivalent Northern Hemisphere expression. Neither of these is really a global mode, although they covary on long time scales in association with tropical or external forcing. For monthly data, the second mode is coherent with Niño-3.4 sea surface temperatures and thus corresponds to El Niño-Southern Oscillation (ENSO), which is truly global in extent. It exhibits more coherent evolution with time and projects strongest onto the interannual variability, where it stands out by far as the dominant mode in the CSEOF analysis. The CSEOF analysis extracts the patterns phase locked with annual cycle and reveals their evolution throughout the year. Standard EOF and varimax analyses are not able to evolve with time of year unless the analysis is stratified by season. Varimax analysis is able to extract the SAM, NAM, and ENSO modes very well, however.

Trenberth, Kevin E.; Stepaniak, David P.; Smith, Lesley

2005-08-01

51

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

NASA Astrophysics Data System (ADS)

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

McHardy, I. M.

2013-03-01

52

Mass loss from interacting close binary systems  

NASA Technical Reports Server (NTRS)

The three well-defined classes of evolved binary systems that show evidence of present and/or past mass loss are the cataclysmic variables, the Algols, and Wolf-Rayet stars. It is thought that the transformation of supergiant binary systems into the very short-period cataclysmic variables must have been a complex process. The new evidence that has recently been obtained from the far ultraviolet spectra that a certain subclass of the Algols (the Serpentids) are undergoing fairly rapid evolution is discussed. It is thought probable that the remarkable mass outflow observed in them is connected with a strong wind powered by accretion. The origin of the circumbinary clouds or flat disks that probably surround many strongly interacting binaries is not clear. Attention is also given to binary systems with hot white dwarf or subdwarf components, such as the symbiotic objects and the BQ stars; it is noted that in them both components may be prone to an enhanced stellar wind.

Plavec, M. J.

1981-01-01

53

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

SciTech Connect

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.

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

2011-09-10

54

Automated mass spectrometer analysis system  

NASA Technical Reports Server (NTRS)

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

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

1982-01-01

55

Alternative variable transformation for simulation of multibody dynamic systems  

NASA Astrophysics Data System (ADS)

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

Yang, Li-Farn

1995-03-01

56

Estimating fossil hominin body mass from cranial variables: an assessment using CT data from modern humans of known body mass.  

PubMed

Body mass estimates are integral to a wide range of inferences in paleoanthropology. Most techniques employ postcranial elements, but predictive equations based on cranial variables have also been developed. Three studies currently provide regression equations for estimating mass from cranial variables, but none of the equations has been tested on samples of known mass. Nor have the equations been compared to each other in terms of performance. Consequently, this study assessed the performance of existing cranial equations using computed tomography scans from a large, documented sample of modern humans of known body mass. Virtual models of the skull were reconstructed and measured using computer software, and the resulting variables were entered into three sets of published regression equations. Estimated and known body masses were then compared. For most equations, prediction errors were high and few individuals were estimated within ±20% of their known mass. Only one equation satisfied the accuracy criteria. In addition, variables that had been previously argued to be good predictors of mass in hominins, including humans, did not estimate mass reliably. These results have important implications for paleoanthropology. In particular, they emphasize the need to develop new equations for estimating fossil hominin body mass from cranial variables. PMID:24615366

Elliott, Marina; Kurki, Helen; Weston, Darlene A; Collard, Mark

2014-06-01

57

Existence of particular solutions in the generalised restricted problem of three bodies with variable masses  

NASA Astrophysics Data System (ADS)

The restricted problem of three bodies with variable masses is considered. It is assumed that the infinitesimal body is axisymmetric with constant mass and the finite bodies are spherical with variable masses such that the ratio of their masses remains constant. The motion of the finite bodies are determined by the Gylden-Meshcherskii (1952) problem. It is seen that the collinear, triangular, and coplanar solutions do not exist, but these solutions exist when the infinitesimal body be a spherical.

El-Shaboury, S. M.

1990-12-01

58

Integrating mass storage and file systems  

Microsoft Academic Search

The authors describe current and anticipated work at the Center for Information Technology Integration at the University of Michigan in developing and integrating mass storage with distributed file systems, specifically with the Andrew File System (AFS). They present a specific approach to integrating AFS with mass storage: they consider the mass store itself to be the file system, not a

C. J. Antonelli; P. Honeyman

1993-01-01

59

Development of variable bit rate disk system  

NASA Astrophysics Data System (ADS)

CD size video disc employing the MPEGG2 system for recording moving pictures, is highly desired. However, it has been difficult to record a movie of more than 2 hours without causing a picture quality degradation. This problem has been resolved by the authors by applying a variable bit rate coding scheme. The variable bit rate coding scheme allows to allocate less codes to simple pictures and more to the portions that are needed. Therefore, a total generated code amount can be reduced with the adoption of the variable scheme, this allows to realize more flexible formats in recorded program length, which have not been possible before. This paper covers the coding, recording, and reproduction technologies of the newly developed disc system employing the variable bit rate coding scheme realized this time.

Yokouchi, Kentaro; Sugiyama, Kenji; Fujiwara, Mitsuaki; Tanaka, Kohji; Nemoto, Shigeru; Iwata, Kazumi

1995-09-01

60

Vehicular variable-parameter METRRA system  

Microsoft Academic Search

The report and instruction manual is intended to describe the Variable Parameter Metal Re-Radiating Radar (METRRA) System (hereafter designated as the VP METRRA), depict its performance, and provide operating and maintenance instructions. A METRRA system differs from conventional radar primarily in that the METRRA uses a third-harmonic return from a target while a conventional radar uses a return at the

R. F. Elsner

1974-01-01

61

Variable Acuity Remote Viewing System \\/VARVS  

Microsoft Academic Search

The Variable Acuity Remote Viewing System (VARVS) is described. The system does not necessitate a large bandwidth in order to generate a large field of view at eye-limited resolution. A remote viewing link with a field of view of 160 degrees at a 4-MHz bandwidth is supported by an extreme aspheric foveal sensor and projection lens. A demonstration model has

G. Licis

1977-01-01

62

Investigation of the regular motion of bodies of variable mass in a gravitational field with allowance for relativistic effects  

Microsoft Academic Search

The motion of many material points with variable masses that are analytic functions of time in a post-Newtonian gravitational field is investigated, taking into account general-relativistic effects. A solution to the relevant system of differential equations of regular motion relative to some absolute coordinate system is obtained as a series expansion in powers of time that converges on a certain

N. G. Magnaradze

1978-01-01

63

Mass content and mass distribution of the asteroid system  

Microsoft Academic Search

The total mass of the asteroid system is determined as approximately 3 by 10 to the 21st power kg on the basis of recent data concerning asteroid masses, diameters, reflectivities, and probable compositions. Eighty percent of this total is attributed to the carbonaceous type (assumed density 2600 kg\\/cu m) and 20% to the silicaceous type, including the Vesta type (assumed

L. Kresak

1977-01-01

64

Regional ice-mass variability in Greenland from GRACE, InSAR and surface-mass balance modelling  

Microsoft Academic Search

The Gravity Recovery and Climate Experiment (GRACE) satellite mission has allowed the resolution of temporal variations in the Earth's gravity field to serve as a new observable for monitoring mass changes in cryosphere. Here, we analyse the GRACE time series from August 2002 to August 2008 with regards to regional ice-mass variability in Greenland. We smooth the monthly GRACE gravity

Zdenek Martinec; Jonathan Bamber; Ingo Sasgen; Michiel van den Broeke

2010-01-01

65

Interesting examples of supervised continuous variable systems  

NASA Technical Reports Server (NTRS)

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.

Chase, Christopher; Serrano, Joe; Ramadge, Peter

1990-01-01

66

Mass Transfer in Binary Star Systems  

NSDL National Science Digital Library

An overview of the process of mass loss of a Star is explained, specifically if the Star is in a Binary System. The website goes through the mass transfer process, its mechanisms, and its consequences.

Seligman, Courtney

2007-06-05

67

Temporal variability of mass transport across Canary Islands Channels  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

68

Quantifying decoherence in continuous variable systems  

Microsoft Academic Search

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

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

2005-01-01

69

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

SciTech Connect

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).

NONE

1995-12-31

70

Variable pressure power cycle and control system  

DOEpatents

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.

Goldsberry, Fred L. (Spring, TX) [Spring, TX

1984-11-27

71

Validation of GRACE time variable gravity against atmospheric mass variations  

Microsoft Academic Search

The GRACE gravity satellite mission is designed to deliver maps of the static and time variable Earth's gravity field with an unprecedented accuracy. GRACE will resolve temporal variations in gravity at length scales of a few hundred km and larger, and produce a complete global map once every 30 days. In order to Calibrate\\/Validate (Cal\\/Val) GRACE data, we must select

I. Velicogna; J. Wahr; G. Hajj

2003-01-01

72

Variable fragmentation mass spectrometry using chemi-ionization  

NASA Technical Reports Server (NTRS)

A description is given of experiments which provide a verification of three features of Penning ionization mass spectrometry. One of these features is related to the ability to simplify a molecular fragmentation pattern and to intensify the molecular ion peak. Another feature is concerned with the ability to identify uniquely geometric isomers which are indistinguishable using high-energy electron impact methods. The third feature involves the ability to identify components in a mixture, which cannot be discerned using electron impact or chemical ionization methods alone. The investigation shows that Penning ionization is an efficient soft ionization technique which can be used to simplify mass spectra of pure compounds as well as mixtures.

Laudenslager, J. B.; Theard, L. P.

1978-01-01

73

Visualization of rock mass classification systems  

Microsoft Academic Search

A rock mass classification system is intended to classify and characterize the rock masses, provide a basis for estimating\\u000a deformation and strength properties, supply quantitative data for mine support estimation, and present a platform for communication\\u000a between exploration, design and construction groups. In most widely used rock mass classification systems, such as RMR and Q systems, up to six parameters

Ming Cai; Peter Kaiser

2006-01-01

74

The security of mass transport ticketing systems  

NASA Astrophysics Data System (ADS)

Mass transport ticketing systems in most developed countries are making a rapid transition from ‘traditional’ paper or carton-based ticketing systems towards a contactless ‘smart card‘ based approach. This article discusses the main IT security aspects of mass transport ticketing systems (metro, bus, etc).

Sel, Marc; Seys, Stefaan; Verheul, Eric

75

Term and variable selection for non-linear system identification  

Microsoft Academic Search

The purpose of variable selection is to pre-select a subset consisting of the significant variables or to eliminate the redundant variables from all the candidate variables of a system under study prior to model term detection. It is required that the selected significant variables alone should sufficiently represent the system. Generally, not all the model terms, which are produced by

H. L. Wei; S. A. Billings; J. Liu

2004-01-01

76

Dynamically variable spot size laser system  

NASA Technical Reports Server (NTRS)

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.

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

2012-01-01

77

Interannual Variability of Patterns of Atmospheric Mass Distribution  

Microsoft Academic Search

Using the 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40) for 1958 to 2001, adjusted for bias over the southern oceans prior to 1979, an analysis is made of global patterns of monthly mean anomalies of atmospheric mass, which is approximately conserved globally. It differs from previous analyses of atmospheric circulation by effectively area weighting surface or sea

Kevin E. Trenberth; David P. Stepaniak; Lesley Smith

2005-01-01

78

Interannual Variability of Patterns of Atmospheric Mass Distribution  

Microsoft Academic Search

Using the 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA- 40) for 1958 to 2001, adjusted for bias over the southern oceans prior to 1979, an analysis is made of global patterns of monthly mean anomalies of atmospheric mass, which is approximately conserved globally. It differs from previous analyses of atmospheric circulation by effectively area weighting surface or

Kevin E. Trenberth; David P. Stepaniak; Lesley Smith

2005-01-01

79

Quantum Information with Continuous Variable systems  

NASA Astrophysics Data System (ADS)

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

Rodó, Carles

2010-05-01

80

A Method to Estimate the Masses of Asymptotic Giant Branch Variable Stars  

NASA Astrophysics Data System (ADS)

AGB variable stars are at the transient phase between low and high mass-loss rates; estimating the masses of these stars is necessary to study the evolutionary processes and mass-loss processes during the AGB stage. We applied the pulsation constant theoretically derived by Xiong and Deng (2007 MNRAS, 378, 1270) to 15 galactic AGB stars in order to estimate their masses. We found that using the pulsation constant is effective to estimate the mass of a star pulsating with two different pulsation modes, such as S Crt and RX Boo, which provides mass estimates comparable to theoretical results of AGB star evolution. We also extended the use of the pulsation constant to single-mode variables, and analyzed the properties of AGB stars related to their masses.

Takeuti, Mine; Nakagawa, Akiharu; Kurayama, Tomoharu; Honma, Mareki

2013-06-01

81

Multivariate mixture analysis using reduced-mass-resolution membrane introduction mass spectrometry and variable selection  

Microsoft Academic Search

The feasibility of analyzing mixtures of spectrally similar analytes with low resolution mass spectrometers coupled with membrane introduction was studied. The performance of the multivariate calibration of an isometric ethyl benzene and p-xylene mixture remained essentially unchanged as the mass resolution degraded. The calibration performance also improved slightly as the data used for calibration decreased from the full mass spectra

William P. Gardner; John H. Callahan; James E. Girard; Ronald E. Shaffer

1999-01-01

82

Variable/Multispeed Rotorcraft Drive System Concepts  

NASA Technical Reports Server (NTRS)

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.

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

2009-01-01

83

The water mass variability on the Romanian Black Sea shelf  

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

84

NEREUS Nemertes: Embedded Mass Spectrometer Control System.  

National Technical Information Service (NTIS)

In this thesis, the author presents Nemertes System, a software suite to control an embedded autonomous mass spectrometer. The author first evaluate previous control systems for the hardware and evaluate a set of software design goals. The NSystem softwar...

A. S. Champy

2004-01-01

85

Sherpa moving mass entry descent landing system  

NASA Technical Reports Server (NTRS)

We describe Sherpa - a Strap-on High-altitude Entry Reconnaissance and Precision Aeromaneuver system that utilizes a moving mass system within an entry capsule to land a spacecraft precisely onto the surface of Mars.

Balaram, J.

2005-01-01

86

Nutrient distributions, variability, and budgets in the Laptev Ssa system  

NASA Astrophysics Data System (ADS)

Studies of nutrient distribution and variability have a great ecological importance. Nutrients (silicate, phosphate and nitrate) are a mineral base for primary production in seawater. Nutrient budgets a indicate sea system metabolism. The aim of the report is to show the results of multiyear studies of nutrient distributions and it is budgeting in the Laptev Sea. New data were obtained in the recent Russian-German expeditions in frames of the bilateral project “Laptev Sea System”. Archive data of Arctic and Antarctic Research Institute were accumulated in the US-Russian Hydrochemical Atlas of the Arctic Ocean. Both of these data sets were used for our studies. The Laptev Sea is a region with highly variable physical processes, and high and variable rates of primary production and organic matter recycling. Extreme environmental changes (pulsing river run-off, coastal erosion, weather and ice conditions, seasonality of biological processes) cause extremely wide range of nutrient variability in space and time. The theory of structural zones and water mass formation is used to explain complicated nutrient distributions and variability. Transport and transformation of substances, including nutrients, in different structural zones occur in different ways. More then 70 % of the shallow Laptev Sea shelf is influenced by river water. Nutrient budgets in the river plume area were calculated for summer and winter according to the LOICZ recommendations. Budgeting results show that the system is acts as a net sink of dissolved inorganic phosphorus and nitrogen, excluding the bottom layer in winter. The system is also net nitrogen fixing in both summer and winter. It is necessary to notice, that the system is net autotrophic despite of the large river runoff.

Nitishinsky, M.; Pivovarov, S.

2003-04-01

87

Miniaturization of Mass Spectrometry Analysis Systems  

PubMed Central

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.

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

2010-01-01

88

Equations of Motion of the Elliptical Restricted Problem of Three Bodies with Variable Masses  

NASA Astrophysics Data System (ADS)

The differential equations of motion of the elliptical restricted problem of three bodies with variable masses are derived with the help of Meshcherskii's transformation. Here we see that these equations of motion differ from the equations of motion of the elliptical restricted problem of three bodies with constant mass only by a factor ?=(?2-??).

Jha, Subodh Kumar; Shrivastava, A. K.

2001-01-01

89

Libration points of the restricted problem of three bodies of variable mass  

NASA Astrophysics Data System (ADS)

Consideration is given to the restricted problem of three bodies of variable mass with an isotropic mass variation of the main bodies. The unified law of Meshcherskii is used to determine new (complanar) libration points, located outside the revolution plane of the main bodies.

Bekov, A. A.

1988-02-01

90

A Particular Case of the Restricted Three-Body Problem with Variable Masses  

Microsoft Academic Search

Equations of motion are obtained for a particle in the restricted three-; body problem with variable finite masses for which Kepler's third law holds at ; any moment of time. When the finite masses are subject to a particular law of ; decrease, an integral is given which is analogous to Jacobi's integral in the ; restricted three-body problem with

E. P. Razbitnaya

1961-01-01

91

Mass balance study of gravitational mass movements in proglacial systems  

NASA Astrophysics Data System (ADS)

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.

Rohn, Joachim; Vehling, Lucas; Moser, Michael

2013-04-01

92

Magnetized fragmented mass transfer in cataclysmic variables: AE Aquarii, a trial case  

NASA Astrophysics Data System (ADS)

This paper examines the effect of secondary-star magnetic activity in AE Aquarii on the mass-transfer process. The results can be extrapolated to cataclysmic variables in general. Based upon the evolution of the system, the surface polar field of the secondary star has been constrained to values of the order of B2,?~ 1000 G. This may indicate the presence of a global magnetic field on the star, making magnetic activity on the stellar surface at least plausible. We have shown that magnetic fields of the order of B>= 300 G will effectively curtail the mass-transfer process through the L1 point, resulting in a fragmentation of the mass-transfer flow as it is forced through the magnetic obstruction, while magnetic fields with values B < 250 G will be advected along with the fluid through the L1 region. This scenario will result in the field being pinched off, resulting in an inhomogeneous or `blobby' magnetized mass flow towards the compact object. We show that magnetic flux conservation will result in these magnetic fields reaching values of Bblob~ 3000 G close to the white dwarf, giving rise to the observed radio outbursts due to the violent encounter with the fast-rotating white-dwarf magnetosphere. Within this framework, optical flares can also be explained in terms of the collisional interaction between a spectrum of denser unmagnetized blobs in the fragmented flow after ejection from the system by the magnetospheric propeller. This may explain the apparent anticorrelation between the non-thermal radio and thermal optical flares seen in AE Aquarii. Supplementing the ideas above, it has been shown that extended prominences in the L1 region may also be instrumental in producing fragmented and magnetized mass transport. Compressed fragments of fluid will be released from these structures when the fluid pressure dominates the magnetic pressure inside. Reconnection at the foot points may initiate episodes of particle acceleration and non-thermal emission when these structures interact with the propeller, followed by enhanced mass transfer and optical brightening of the source when the mass transfer encounters the propeller, leading to the same anticorrelation between radio and optical outbursts.

Meintjes, P. J.

2004-08-01

93

A Mass-Selective Variable-Temperature Drift Tube Ion Mobility-Mass Spectrometer for Temperature Dependent Ion Mobility Studies  

NASA Astrophysics Data System (ADS)

A hybrid ion mobility-mass spectrometer (IM-MS) incorporating a variable-temperature (80-400 K) drift tube is presented. The instrument utilizes an electron ionization (EI) source for fundamental small molecule studies. Ions are transferred to the IM-MS analyzer stages through a quadrupole, which can operate in either broad transmission or mass-selective mode. Ion beam modulation for the ion mobility experiment is accomplished by an electronic shutter gate. The variable-temperature ion mobility spectrometer consists of a 30.2 cm uniform field drift tube enclosed within a thermal envelope. Subambient temperatures down to 80 K are achievable through cryogenic cooling with liquid nitrogen, while elevated temperatures can be accessed through resistive heating of the envelope. Mobility separated ions are mass analyzed by an orthogonal time-of-flight (TOF) mass spectrometer. This report describes the technological considerations for operating the instrument at variable temperature, and preliminary results are presented for IM-MS analysis of several small mass ions. Specifically, mobility separations of benzene fragment ions generated by EI are used to illustrate significantly improved (greater than 50%) ion mobility resolution at low temperatures resulting from decreased diffusional broadening. Preliminary results on the separation of long-lived electronic states of Ti+ formed by EI of TiCl4 and hydration reactions of Ti+ with residual water are presented.

May, Jody C.; Russell, David H.

2011-07-01

94

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

95

A comparison of two total contact cast constructs with variable body mass.  

PubMed

Objective: There is a growing body of evidence implicating obesity as having a negative effect on the development and treatment of diabetic foot disease. The aim of this study was to increase the body of knowledge on the effects of obesity on foot function, specifically as it relates to peak plantar pressures in the total contact cast (TCC). Our investigational objectives were to compare the effect of two different TCC designs on mean peak plantar pressures, and to evaluate the efficacy of two TCC constructs with increasing body mass. Method: The primary outcome measure was mean peak plantar pressure in the heel, midfoot, forefoot and first metatarsal as measured with an in-shoe pressure measurement system. The variables were patient weight (from 'normal' body mass index (BMI) to 'overweight', 'obese' and 'morbidly obese') and the TCC construct (with both a standard and alternate cast design). The standard TCC is considered the gold standard for off-loading of the diabetic foot. The alternate TCC was designed to use the essential offloading component of the traditional TCC, namely the total contact leg section, with use of an open cell polyurethane foam to transfer load from the foot to the lower leg, thereby offloading the foot by suspending it within a padded fiberglass walking cast. Results: We did not observe statistically significant differences in mean peak plantar pressures in any plantar foot anatomic area or with any body mass between the two TCC designs. Conclusion: Based on the results, we concluded that the alternate TCC design provides another viable TCC construct option for practitioners working with the neuropathic foot. This investigation also provides specific data on changes that occur in peak plantar pressures with use of the total contact cast and variable BMIs. Declaration of interest: none. PMID:25041431

Pirozzi, Kelly; McGuire, James; Meyr, Andrew J

2014-07-01

96

Air Pressure Controlled Mass Measurement System  

NASA Astrophysics Data System (ADS)

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.

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

97

Dual output variable pitch turbofan actuation system  

NASA Technical Reports Server (NTRS)

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

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

1976-01-01

98

System Identification with Reaction-Mass Devices.  

National Technical Information Service (NTIS)

Reaction-mass devices are to be used in a dual role: first for the purpose of system identification, and second for the purpose of vibration suppression. Unlike ground-based shakers, reaction-mass devices have a position constraint which must be maintaine...

R. Quan

1995-01-01

99

Variable temperature seat climate control system  

DOEpatents

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.

Karunasiri, Tissa R. (Van Nuys, CA); Gallup, David F. (Pasadena, CA); Noles, David R. (Glendale, CA); Gregory, Christian T. (Alhambra, CA)

1997-05-06

100

Variable acuity remote viewing system flight demonstration  

NASA Technical Reports Server (NTRS)

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.

Fisher, R. W.

1983-01-01

101

Mass Storage Performance Information System  

NASA Technical Reports Server (NTRS)

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.

Scheuermann, Peter

2000-01-01

102

Modelling of ? Scorpii, a high-mass binary with a ? Cep variable primary component  

NASA Astrophysics Data System (ADS)

High-mass binary stars are known to show an unexplained discrepancy between the dynamical masses of the individual components and those predicted by models. In this work, we study Sigma Scorpii, a double-lined spectroscopic binary system consisting of two B-type stars residing in an eccentric orbit. The more massive primary component is a ? Cep-type pulsating variable star. Our analysis is based on a time series of some 1000 high-resolution spectra collected with the CORALIE spectrograph in 2006, 2007, and 2008. We use two different approaches to determine the orbital parameters of the star; the spectral disentangling technique is used to separate the spectral contributions of the individual components in the composite spectra. The non-LTE-based spectrum analysis of the disentangled spectra reveals two stars of similar spectral type and atmospheric chemical composition. Combined with the orbital inclination angle estimate found in the literature, our orbital elements allow a mass estimate of 14.7 ± 4.5 and 9.5 ± 2.9 M? for the primary and secondary component, respectively. The primary component is found to pulsate in three independent modes, of which two are identified as fundamental and second overtone radial modes, while the third is an l = 1 non-radial mode. Seismic modelling of the pulsating component refines stellar parameters to 13.5^{+0.5}_{-1.4} and 8.7^{+0.6}_{-1.2} M?, and delivers radii of 8.95^{+0.43}_{-0.66} and 3.90^{+0.58}_{-0.36} R? for the primary and secondary, respectively. The age of the system is estimated to be ˜12 Myr.

Tkachenko, A.; Aerts, C.; Pavlovski, K.; Degroote, P.; Pápics, P. I.; Moravveji, E.; Lehmann, H.; Kolbas, V.; Clémer, K.

2014-07-01

103

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

NASA Astrophysics Data System (ADS)

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.

Lehoczky, Annamária; Kern, Zoltán; Pongrácz, Rita

2014-05-01

104

Evaluating Surface Mass Balance spatiotemporal variability in a regional climate model over Greenland using an ice sheet model and GRACE  

NASA Astrophysics Data System (ADS)

The Surface Mass Balance (SMB) of the Greenland Ice Sheet (GIS) is an important contributor to changes in sea level, now, and in the future. Both modeling and observational studies have revealed accelerating loss of mass over Greenland, of which approximately 50% has been attributed to changes in SMB, with the other 50% coming from increases in glacial discharge. Regional Climate Model (RCM) estimates of SMB change are currently among the best means of obtaining estimates of SMB timeseries. Measurements of SMB over the GIS are sparse, limiting the ability to validate SMB estimates. Several studies have compared ice-sheet wide changes in mass measured by the Gravity Recovery and Climate Experiment (GRACE), satellite-derived ice discharge measurements, and RCM results, to reveal a general agreement in ice-sheet wide mass changes over the past decade, but no detailed analysis of the spatiotemporal variability of simulated SMB estimates has been conducted using these datasets. Here we make use of a high resolution gridded 50 km GRACE Mascon solution at a monthly temporal resolution, satellite-derived discharge estimates, and sub-annual estimates of mass change from the Ice Sheet System Model (ISSM), to evaluate spatiotemporal variability in SMB simulated by the Modèle Atmosphérique Régionale (MAR), a regional climate model applied over the GIS. We reveal spatial biases in MAR SMB, but find a general agreement for GIS-wide SMB fluctuations. A lag in the seasonal cycle of mass loss potentially reveals a water storage cycle in ablation zone areas.

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

2013-12-01

105

Control system for a infinitely variable transmission  

SciTech Connect

This patent describes a control system for an infinitely variable transmission for transmitting power of an internal combustion engine to driving wheels of a motor vehicle, the transmission having a drive pulley including a hydraulically shiftable first disc and a first hydraulic cylinder for shifting the first disc, a driven pulley including a hydraulically shiftable second disc and a second hydraulic cylinder for operating the second disc, and a belt engaged with both pulleys, the system including a first hydraulic circuit having an oil pump of the vehicle and for supplying oil to the first and second hydraulic cylinders, and a transmission ratio control valve disposed in the first hydraulic circuit and having a shiftable spool so as to control the oil being supplied to the first hydraulic cylinder of the drive pulley to change the transmission ratio of the transmission, the improvement in the system comprising: a second hydraulic circuit having a pressure regulator valve means communicating with the pump for maintaining pressure of oil supplied by the pump as control oil at a constant value, the second hydraulic circuit for supplying the control oil to the transmission ratio control valve so as to shift the spool; control valve means provided in the second hydraulic circuit for controlling the amount of the control oil supplied to the transmission ratio control valve so as to shift the spool.

Morimoto, Y.

1988-11-15

106

Control system for a continuously variable transmission  

SciTech Connect

This patent describes a control system for a continuously variable transmission for transmitting the power of an internal combustion engine for driving a motor vehicle. The transmission has a drive pulley having a hydraulically shiftable disc and a hydraulic cylinder for operating the disc, a driven pulley including a hydraulically shiftable disc and a hydraulic cylinder for operating the latter disc, and a belt engaged with both pulleys. The control system includes a first hydraulic circuit having a pump for supplying oil to both the hydraulic cylinders, and a transmission ratio control valve having a shiftable spool for controlling the oil supplied to at least one of the cylinders. The improvement in the control system comprises: means for shifting the spool of the transmission ratio control valve; means for sensing operating conditions of the engine and transmission and for producing a first signal dependent on the conditions; means for producing a control signal to shift the spool to control the transmission ratio of the transmission to the desired transmission ratio value; and a means for detecting a steady state driving condition and for producing a steady state signal.

Tanaka, H.; Morimoto, Y.

1989-01-03

107

Investigating mass transfer in symbiotic systems with hydrodynamic simulations  

NASA Astrophysics Data System (ADS)

We investigate gravitationally focused wind accretion in binary systems consisting of an evolved star with a gaseous envelope and a compact accreting companion. We study the mass accretion and formation of an accretion disk around the secondary caused by the strong wind from the primary late-type component using global 2D and 3D hydrodynamic numerical simulations. In particular, the dependence on the mass accretion rate on the mass loss rate, wind temperature and orbital parameters of the system is considered. For a typical slow and massive wind from an evolved star the mass transfer through a focused wind results in rapid infall onto the secondary. A stream flow is created between the stars with accretion rates of a 2-10% percent of the mass loss from the primary. This mechanism could be an important method for explaining periodic modulations in the accretion rates for a broad range of interacting binary systems and fueling of a large population of X-ray binary systems. We test the plausibility of these accretion flows indicated by the simulations by comparing with observations of the symbiotic CH Cyg variable system.

de Val-Borro, Miguel; Karovska, Margarita; Sasselov, Dimitar D.

2014-06-01

108

Localized spectral analysis of global satellite gravity fields for recovering time-variable mass redistributions  

Microsoft Academic Search

A spatiospectral localization method is discussed for processing the global geopotential coefficients from satellite mission data to investigate time-variable gravity. The time-variable mass variation signal usually appears associated with a particular geographical area yielding inherently regional structure, while the dependence of the satellite gravity errors on a geographical region is not so evident. The proposed localization amplifies the signal-to-noise ratio

S.-C. Han; P. Ditmar

2007-01-01

109

Localized spectral analysis of global satellite gravity fields for recovering time-variable mass redistributions  

Microsoft Academic Search

A spatiospectral localization method is discussed for processing the global geopotential coefficients from satellite mission\\u000a data to investigate time-variable gravity. The time-variable mass variation signal usually appears associated with a particular\\u000a geographical area yielding inherently regional structure, while the dependence of the satellite gravity errors on a geographical\\u000a region is not so evident. The proposed localization amplifies the signal-to-noise ratio

Shin-Chan Han; Pavel Ditmar

2008-01-01

110

Dynamic shakedown of structures with variable appended masses and subjected to repeated excitations  

Microsoft Academic Search

Elastic shakedown for discrete, or finite-element discretized, structures subjected to combinations of static and time-variable loads is addressed in the hypothesis of elastic-perfectly plastic material behavior. The static load is conceived as the weight of an additional mass appended to the structure, whereas the time-variable load is conceived as an unknown sequence of excitations belonging to a specified domain, with

G. Borino; C. Polizzotto

1996-01-01

111

Mid-infrared Variability and Mass Accretion Toward NGC 2264 Protostars  

NASA Astrophysics Data System (ADS)

Variable mass accretion has been suggested to be an important aspect of protostar formation. Mid-infrared wavelength observations trace variations in accretion luminosity and thus can probe mass accretion on sub-AU scales. We present results from the Spitzer YSOVAR campaign towards class I protostars in NGC 2264. The precise (0.02 mag) several hour cadence light curves at 3.6 and 4.5 microns show that young star variability is ubiquitous, with a variety of morphologies and time scales. A structure function analysis shows the light curves, on average, have a power-law behavior up to 30 days. Moreover, the average structure function is the same for protostars in NGC 2264 and Orion. The power-law behavior suggests a stochastic process such as turbulent mass accretion. We discuss theoretical models and the prospects for determining mass accretion rates from synoptic studies.

Terebey, Susan; Cody, Ann Marie

2014-07-01

112

An analysis of space power system masses  

NASA Technical Reports Server (NTRS)

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.

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

1990-01-01

113

Online mass storage system detailed requirements document  

NASA Technical Reports Server (NTRS)

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.

1976-01-01

114

INFRARED VARIABILITY OF THE GLIESE 569B SYSTEM  

SciTech Connect

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.

Kenworthy, Matthew A. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Scuderi, Louis J., E-mail: kenworthy@strw.leidenuniv.nl [Institute for Astronomy, 2680 Woodlawn Drive, Honolulu, HI 96822-1839 (United States)

2012-06-20

115

An unusual very low-mass high-amplitude pre-main sequence periodic variable  

NASA Astrophysics Data System (ADS)

Aims: We have investigated the nature of the variability of CHS 7797, an unusual periodic variable in the Orion Nebula Cluster. Methods: An extensive I-band photometric data set of CHS 7797 was compiled between 2004-2010 using various telescopes. Further optical data have been collected in R and z' bands. In addition, simultaneous observations of the ONC region including CHS 7797 were performed in the I,J,Ks & IRAC 3.6 and 4.5 ?m bands over a time interval of ?40 d. Results: CHS 7797 shows an unusual large-amplitude variation of ?1.7 mag in the R,I, and z' bands with a period 17.786 ± 0.03 d (FAP = 1 × 10-15%). The amplitude of the brightness modulation decreases only slightly at longer wavelengths. The star is faint during ?2/3 of the period and the shape of the phased light-curves for the seven different observing seasons shows minor changes and small-amplitude variations. Interestingly, there are no significant colour-flux correlations for ? ? 2 ?m, while the object becomes redder when fainter at longer wavelengths. CHS 7797 has a spectral type of M 6 and an estimated mass between 0.04-0.1 M?. Conclusions: The analysis of the data suggests that the periodic variability of CHS 7797 is most probably caused by an orbital motion. Variability as a result of rotational brightness modulation by a hot spot is excluded by the lack of any colour-brightness correlation in the optical. The latter indicates that CHS 7797 is most probably occulted by circumstellar matter in which grains have grown from typical 0.1 ?m to ?1-2 ?m sizes. We discuss two possible scenarios in which CHS 7797 is periodically eclipsed by structures in a disc, namely that CHS 7797 is a single object with a circumstellar disc, or that CHS 7797 is a binary system, similar to KH 15D, in which an inclined circumbinary disc is responsible of the variability. Possible reasons for the typical 0.3 mag variations in I-band at a given phase are discussed.

Rodríguez-Ledesma, M. V.; Mundt, R.; Ibrahimov, M.; Messina, S.; Parihar, P.; Hessman, F. V.; Alves de Oliveira, C.; Herbst, W.

2012-08-01

116

Analysis on the stability of triangular points in the restricted problem of three bodies with variable mass.  

NASA Astrophysics Data System (ADS)

The stability of triangular points in the restricted problem of three bodies with variable mass is studied. It is found that the region of stability of triangular points does not exist when the restricted problem with constant mass evolves into the problem with variable mass.

Lu, Ting-Wei

117

System-Level Integration of Mass Memory  

NASA Technical Reports Server (NTRS)

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.

Cox, Brian; Mellstrom, Jeffrey; Wysocky, Terry

2008-01-01

118

Alaska SAR Facility mass storage, current system  

NASA Technical Reports Server (NTRS)

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.

Cuddy, David; Chu, Eugene; Bicknell, Tom

1993-01-01

119

The effects of massed versus distributed contractions on the variability of maximal isometric force.  

PubMed

This study evaluated the effect of a massed versus distributed repetition schedule on the variability of force and surface electromyographic (sEMG) activity during maximal voluntary isometric elbow flexion contractions. The massed group (N = 13) performed 15 contractions on 1 day, while the distributed group (N = 13) performed 15 contractions across three consecutive days (five per day). Two retention tests (five contractions each) occurred 2 weeks and 3 months after the final trial of the initial test sessions. Force and sEMG of the biceps and triceps brachii muscles were recorded concurrently. Both groups had comparable increases in force and biceps brachii sEMG that continued over short- and longer-term retention tests (p < 0.05). Triceps brachii sEMG exhibited a more complicated pattern of successive decreases and increases (p < 0.05). The massed repetition schedule resulted in significantly (p < 0.05) less variability in maintaining a constant force [root mean square (RMS) error]. There was a significant decrease in the variability of the force-time and sEMG-time curves as assessed by the variance ratio (VR) (p < 0.05). Only biceps sEMG and VR correlated highly with force VR for the distributed group. Total (biceps + triceps) sEMG magnitude and variability correlated highly with both RMS error and force VR for the massed group. It was concluded that the massed contraction pattern allowed participants to learn how to regulate joint stiffness in addition to the variability of muscle activity. This allowed for greater decreases in RMS error than could be obtained by regulating the variability of muscle activity alone. PMID:24691759

McGuire, Jessica; Green, Lara; Calder, Kristina; Patterson, Jae; Gabriel, David A

2014-07-01

120

Modeling systems with variability using the PROTEUS configuration language  

Microsoft Academic Search

Abstract. To respond to environmentalchanges,and customer specific requirements, industrial software systems must often incorporate many sources of variability. Developers use a diverse range of representatio ns and techniques to achieve this, including structural variability, component version selection, conditional inclusion, and varying derivation processes. This paper advocates specifying allpotential variability within a system using a single formalism. PCL, the configuration language

E. Tryggeseth; B. Gulla; R. Conradi

1985-01-01

121

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

NASA Technical Reports Server (NTRS)

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.

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

1977-01-01

122

The influence of mass-transfer variability on the growth of white dwarfs, and the implications for Type Ia supernova rates  

NASA Astrophysics Data System (ADS)

White dwarfs (WDs) can increase their mass by accretion from companion stars, provided the mass-accretion rate is high enough to avoid nova eruptions. The accretion regimes that allow growth of the WDs are usually calculated assuming constant mass-transfer rates. However, it is possible that these systems are influenced by effects that cause the rate to fluctuate on various time-scales. We investigate how long-term mass-transfer variability affects accreting WDs systems. We show that, if such variability is present, it expands the parameter space of binaries where the WD can effectively increase its mass. Furthermore, we find that the Type Ia supernova (SNIa) rate is enhanced by a factor 2-2.5 to a rate that is comparable with the lower limit of the observed rates. The changes in the delay-time distribution allow for more SNIae in stellar populations with ages of a few Gyr. Thus, mass-transfer variability gives rise to a new formation channel of SNIa events that can significantly contribute to the SNIa rate. Mass-transfer variability is also likely to affect other binary populations through enhanced WD growth. For example, it may explain why WDs in cataclysmic variables are observed to be more massive than single WDs, on average.

Toonen, S.; Voss, R.; Knigge, C.

2014-06-01

123

High Temperature Variable Conductance Heat Pipes for Radioisotope Stirling Systems  

NASA Technical Reports Server (NTRS)

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.

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

2009-01-01

124

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

NASA Astrophysics Data System (ADS)

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.

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

2011-02-01

125

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

NASA Astrophysics Data System (ADS)

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

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

2012-01-01

126

Investigating C IV Line Variability and Multiple Epoch C IV SMBH Mass Estimates  

NASA Astrophysics Data System (ADS)

The CIV emission line in quasar spectra is well-known to show systematic blueshifts, often attributed to accretion disk winds. We investigate the variability of the CIV line properties in a large sample of multi-epoch quasar spectra from the SDSS BOSS survey DR10, focusing on correlations of the blueshift variability with line and continuum properties. Preliminary findings show very weak to no variability in the blueshifting of the region of interest and weak correlation between line blue-shift and change in continuum flux between epochs, indicating near constant outflow speeds. We will also continue to investigate the use of multiple epoch luminosities of the CIV line as a probe of virial mass of the host SMBH. By recalibrating estimates built on the use of single epoch data and correcting for any changes in outflow speed, it is hoped to more finely tune BH mass estimates.

Sharma, Ramon

2014-01-01

127

Control system for an infinitely variable transmission  

SciTech Connect

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

Sakai, Y.

1986-12-09

128

Control system for a continuously variable transmission  

SciTech Connect

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

Sakai, Y.

1987-11-03

129

Heart rate variability in systemic hypertension  

Microsoft Academic Search

Low heart rate (HR) variability is a risk factor for cardiac mortality in various patient populations, but it has not been well established whether patients with long-standing hypertension have abnormalities in the autonomic modulation of HR. Time and frequency domain measures of HR variability were compared in randomly selected, age-matched populations of 188 normotensive and 168 hypertensive males (mean age

Heikki V. Huikuri; Antti Ylitalo; Sirkku M. Pikkujämsä; Markku J. Ikäheimo; K. E. Juhani Airaksinen; Asko O. Rantala; Mauno Lilja; Y. Antero Kesäniemi

1996-01-01

130

Quality control technique to reduce the variability of longitudinal measurement of hemoglobin mass.  

PubMed

The sensitivity of the athlete blood passport to detect blood doping may be improved by the inclusion of total hemoglobin mass (Hb(mass)), but the comparability of Hb(mass) from different laboratories is unknown. To optimize detection sensitivity, the analytical variability associated with Hb(mass) measurement must be minimized. The aim of this study was to investigate the efficacy of using quality controls to minimize the variation in Hb(mass) between laboratories. Three simulated laboratories were set up in one location. Nine participants completed three carbon monoxide (CO) re-breathing tests in each laboratory. One participant completed two CO re-breathing tests in each laboratory. Simultaneously, quality controls containing Low (1-3%) and High (8-11%) concentrations of percent carboxyhemoglobin (%HbCO) were measured to compare hemoximeters in each laboratory. Linear mixed modeling was used to estimate the within-subject variation in Hb(mass), expressed as the coefficient of variation, and to estimate the effect of different laboratories. The analytic variation of Hb(mass) was 2.4% when tests were conducted in different laboratories, which reduced to 1.6% when the model accounted for between-laboratory differences. Adjustment of Hb(mass) values using quality controls achieved a comparable analytic variation of 1.7%. The majority of between-laboratory variation in Hb(mass) originated from the difference between hemoximeters, which could be eliminated using appropriate quality controls. PMID:21535184

Gough, C E; Sharpe, K; Ashenden, M J; Anson, J M; Saunders, P U; Garvican, L A; Bonetti, D L; Gore, C J; Prommer, N

2011-12-01

131

Simulation system modeling for mass customization manufacturing  

Microsoft Academic Search

Emerging rapidly as a new paradigm of the 21st century, mass customization manufacturing (MCM) systems possess some special characteristics that make the modeling of such systems extremely difficult. These characteristics include concurrency, synchronization, and cooperation among subsystems. Moreover, MCM emphasizes shortened product life-cycles, which means production lines have to be changed or reconfigured frequently. Highly flexible and re-configurable factories must

Guixiu Qiao; Charles McLean; Frank Riddick

2002-01-01

132

Mass Transit Living Lab: Improve the System  

NSDL National Science Digital Library

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

Civil And Environmental Engineering Department

133

Bayesian ANN estimates of three-class ideal observer decision variables for classification of mammographic masses  

NASA Astrophysics Data System (ADS)

We are using Bayesian artificial neural networks (BANNs) to classify mammographic masses. We investigated whether a BANN can estimate ideal observer decision variables to distinguish malignant, benign, and false-positive computer detections. Five features were calculated for 143 malignant and 125 benign mass lesions, and for 1049 false-positive computer detections, in 596 mammograms randomly divided into a training and testing set. A BANN was trained on the training set features and applied to the testing set features. We then used a known relation between three-class ideal observer decision variables and that used by a two-class ideal observer when two of three classes are grouped into one class, giving one decision variable for distinguishing malignant from non-malignant detections, and a second for distinguishing true-positive from false-positive computer detections. For comparison, we pooled the training data into two classes in the same two ways and trained two-class BANNs for these two tasks. The three-class BANN decision variables were essentially identical in performance to the specifically trained two-class BANNS. This is consistent with the theoretical observation that three-class ideal observer decision variables are directly related to those used by a two-class ideal observer.

Edwards, Darrin C.; Lan, Li; Metz, Charles E.; Giger, Maryellen L.; Nishikawa, Robert M.

2003-05-01

134

Toward Scalable Benchmarks for Mass Storage Systems  

NASA Technical Reports Server (NTRS)

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.

Miller, Ethan L.

1996-01-01

135

QZ Aurigae: An eclipsing cataclysmic variable with a white dwarf of almost equivalent mass to its companion  

NASA Astrophysics Data System (ADS)

We present CCD photometric monitoring of the classic nova QZ Aurigae (Nova Aur 1964) since 2008 with the 2.4-m telescope at Lijiang station of Yunnan Astronomical Observatory in China, as well as the 2.16-m telescope and the 85-cm telescope at Xionglong station of the National Astronomical Observatory in China. By utilizing eight new eclipse timings and the data from the last literature, published almost 20 years ago, we construct the O - C diagram of this system to analyze the orbital period variation. We find no evidence of long-term orbital period variations in QZ Aur. Moreover, the light curves showing the main eclipse process of the white dwarf suggest the presence of a bright spot component and a disk, as commonly found in nova-like variables. This may reveal high mass accretion and high mass transfer in this system. However, even high mass transfer rates from the donor are inconsistent with our result of no period variations, unless the mass ratio is almost equal to 1. Hence, the observed results here possibly support that the mass of the primary white dwarf is extremely close to that of the donor star in the eclipsing binary QZ Aur.

Shi, Guang; Qian, Sheng-Bang

2014-04-01

136

QZ Aurigae: An eclipsing cataclysmic variable with a white dwarf of almost equivalent mass to its companion  

NASA Astrophysics Data System (ADS)

We present CCD photometric monitoring of the classic nova QZ Aurigae (Nova Aur 1964) since 2008 with the 2.4-m telescope at Lijiang station of Yunnan Astronomical Observatory in China, as well as the 2.16-m telescope and the 85-cm telescope at Xionglong station of the National Astronomical Observatory in China. By utilizing eight new eclipse timings and the data from the last literature, published almost 20 years ago, we construct the O - C diagram of this system to analyze the orbital period variation. We find no evidence of long-term orbital period variations in QZ Aur. Moreover, the light curves showing the main eclipse process of the white dwarf suggest the presence of a bright spot component and a disk, as commonly found in nova-like variables. This may reveal high mass accretion and high mass transfer in this system. However, even high mass transfer rates from the donor are inconsistent with our result of no period variations, unless the mass ratio is almost equal to 1. Hence, the observed results here possibly support that the mass of the primary white dwarf is extremely close to that of the donor star in the eclipsing binary QZ Aur.

Shi, Guang; Qian, Sheng-Bang

2014-05-01

137

Variable elimination in post-translational modification reaction networks with mass-action kinetics.  

PubMed

We define a subclass of chemical reaction networks called post-translational modification systems. Important biological examples of such systems include MAPK cascades and two-component systems which are well-studied experimentally as well as theoretically. The steady states of such a system are solutions to a system of polynomial equations. Even for small systems the task of finding the solutions is daunting. We develop a mathematical framework based on the notion of a cut (a particular subset of species in the system), which provides a linear elimination procedure to reduce the number of variables in the system to a set of core variables. The steady states are parameterized algebraically by the core variables, and graphical conditions for when steady states with positive core variables imply positivity of all variables are given. Further, minimal cuts are the connected components of the species graph and provide conservation laws. A criterion for when a (maximal) set of independent conservation laws can be derived from cuts is given. PMID:22311196

Feliu, Elisenda; Wiuf, Carsten

2013-01-01

138

Modelling Systems with Variability using the PROTEUS Configuration Language  

Microsoft Academic Search

To respond to environmental changes and customer specific require- ments, industrial software systems must often incorporate many sources of vari- ability. Developers use a diverse range of representatio ns and techniques to achieve this, including structural variability, component version selection, condi- tional inclusion, and varying derivation processes. This paper advocates specifying all potential variability within a system using a single

Eirik Tryggeseth; Bjørn Gulla; Reidar Conradi

1995-01-01

139

Variable neural networks for adaptive control of nonlinear systems  

Microsoft Academic Search

This paper is concerned with the adaptive control of continuous-time nonlinear dynamical systems using neural networks. A novel neural network architecture, referred to as a variable neural network, is proposed and shown to be useful in approximating the unknown nonlinearities of dynamical systems. In the variable neural networks, the number of basis functions can be either increased or decreased with

Guoping P. Liu; Visakan Kadirkamanathan; Stephen A. Billings

1999-01-01

140

Expert overseer for mass spectrometer system  

DOEpatents

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.

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

1991-01-01

141

Greenland mass variation from time-variable gravity in the absence of GRACE  

NASA Astrophysics Data System (ADS)

In a recent paper, the authors succeeded in the inference of time-variable gravity from orbit analysis of the CHAMP satellite. The authors demonstrated the potential of the adopted methods by validation against GRACE data and surface height changes from GPS ground stations. This paper presents the capability of orbit analysis for the spatiotemporal quantification of Greenland mass change trends. Based on CHAMP time-variable gravity fields from January 2003 to December 2009, we estimated the ice mass loss over the entire of Greenland to 246±10 Gt/yr. This result is in line with the findings from GRACE data analysis (223±10 Gt/yr) over the same period; the trend estimates differ by only 10%. Moreover, for some areas, the spatial mass variation patterns are in good agreement, pinpointing dominant deglaciation along the Greenland coastline. We conclude that orbit analysis of low-Earth orbiting spacecraft is suitable to assess Greenland mass balance in the absence of the GRACE satellites.

Baur, O.

2013-08-01

142

Mass spectrometer vacuum housing and pumping system  

DOEpatents

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.

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

1996-01-01

143

Mass spectrometer vacuum housing and pumping system  

DOEpatents

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.

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

1996-07-23

144

Studies of Long Period Variability in Neutron Star HMXB Systems  

NASA Technical Reports Server (NTRS)

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

Heindl, William A.

1998-01-01

145

Mass Properties for Space Systems Standards Development  

NASA Technical Reports Server (NTRS)

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).

Beech, Geoffrey

2013-01-01

146

Design and calibration of a single-transducer variable-frequency sonication system  

Microsoft Academic Search

The design of a novel single-transducer variable-frequency sonication system capable of operating at constant acoustic power over the range 20–500 kHz is described. The system employs a mass-loaded sandwich transducer arrangement and a series of transformers to provide an accurate impedance matching circuit. Approximately 0–5 W of acoustic power are produced by the system at typical operating frequencies of 20,

Darcey G Wayment; Dominick J Casadonte

2002-01-01

147

Variability of water mass properties in the Strait of Sicily in summer period of 1998-2013  

NASA Astrophysics Data System (ADS)

The Strait of Sicily plays a crucial role in determining the water mass exchanges and related properties between western and eastern Mediterranean. The presence of sills to the east and west of the Strait of Sicily and the complex seabed topography modulate the thermohaline circulation of the Mediterranean basin. An anti-estuarine circulation is mainly characterized, from a dynamic point of view, by a two-layer system: a surface layer composed of Atlantic Water (AW) flowing eastward, essentially dominated by mesoscale processes, and a subsurface layer composed of Levantine Intermediate Water (LIW) flowing in the opposite direction; the topography appears to play an important role. Furthermore, there are transition water masses with variable hydrological characteristics. The dataset here studied is a time series 16 years long (1998-2013), which highlights the high horizontal and vertical interannual variability affecting the study area. Strong temperature-salinity correlations, in the intermediate layer, for specific time intervals, could be linked to the reversal of sub-surface circulation in the Central Ionian Sea. Moreover, a long-term monitoring of the hydrographic properties of water masses across this strait allow the modelers to assess the performance of hydrological models of this area.

Bonanno, A.; Placenti, F.; Basilone, G.; Mifsud, R.; Genovese, S.; Patti, B.; Di Bitetto, M.; Aronica, S.; Barra, M.; Giacalone, G.; Ferreri, R.; Fontana, I.; Buscaino, G.; Tranchida, G.; Quinci, E. M.; Mazzola, S.

2014-03-01

148

Variable Conductance Heat Pipes for Radioisotope Stirling Systems  

NASA Technical Reports Server (NTRS)

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.

Anderson, William G.; Tarau, Calin

2008-01-01

149

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

NASA Technical Reports Server (NTRS)

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.

Chao, Benjamin F.; Kuang, Weijia

2003-01-01

150

Variable-speed capacity control in refrigeration systems  

Microsoft Academic Search

This paper presents a review of the application of variable-speed capacity control to refrigeration systems. The aim is to put together diversified information in a single source and to appraise recent advances in variable-speed technology. The review reveals that although variable-speed drives based on inverters have been applied successfully to control the capacity of rotodynamic machines, such as pumps and

T. Q. Qureshi; S. A. Tassou

1996-01-01

151

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

NASA Astrophysics Data System (ADS)

The water mass distribution in the eastern North Atlantic Ocean (39-45°N, 16-22°W) during 2001 was determined for the upper 2000 m within the frame of the French research program POMME, using an extended Optimum Multiparameter analysis which included both conservative and nonconservative tracers. The presence of eastern North Atlantic Central Water in its subtropical and subpolar branches, Mediterranean Water, and Labrador Sea Water was considered. The results were used in combination with mass fluxes in order to determine the transports taking place in the region and analyze the variability observed both in the direction and magnitude of the fluxes, as well as to determine the relative contribution of each water mass to the flows. The high variability of the area was evident in the changes in flux direction and magnitude; the total input into the POMME region varied from POMME 1 (3.8 Sv southward) to POMME 3 (8.8 Sv northward). Our findings, depending on the cruise considered, corroborate most of the previous and often conflicting studies in the area, both in the flow direction and magnitude, suggesting that in highly dynamic areas such as this one, estimating annual trends from individual cruises might not provide accurate descriptions of the overall transports.

Barbero, L.; GonzáLez-DáVila, M.; Santana-Casiano, J. M.; ÁLvarez, M.

2010-03-01

152

FTO genotype is associated with phenotypic variability of body mass index  

PubMed Central

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

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

2013-01-01

153

Variable Structure System for Electric Arc Furnace Control  

Microsoft Academic Search

Variable structure controllers that can be effectively applied to control an electric arc furnace are investigated in this paper. A gereral formulation and solution of the variable structure system design problem is presented together with some guidlines for the choice of a suitable model following. A state space reduction method is applied to reduce the dominant dynamic order and hence

M. A. Zohdy; Jun Liu

1988-01-01

154

Variability in Second Language Development from a Dynamic Systems Perspective  

ERIC Educational Resources Information Center

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…

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

2008-01-01

155

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

NASA Technical Reports Server (NTRS)

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.

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

1995-01-01

156

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

NASA Technical Reports Server (NTRS)

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.

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

1983-01-01

157

Non-Conservative Evolution of Spherical and Distorted Low Mass Close Binary Systems Including Systemic Mass Loss and Gravitational Radiation.  

NASA Astrophysics Data System (ADS)

The evolution of low mass, close binary systems driven primarily by gravitational radiation loss is studied within the framework of both a semi-analytic formulation and a sophisticated numerical (Henyey) method. One of the major advantages associated with the semi-analytic formulation is the facility with which it can be applied to a wide range of physical phenomena. In particular, the effects of several modes of systemic (advective) mass loss have been investigated including a mode which crudely models novae events. An allowance for the possible uncertainty in the Landau-Lifshitz formula for quadrupole radiation has also been incorporated. Although our investigation is restricted to the use of equilibrium (main sequence) models for the mass-losing secondary, it is possible to comment on the value of the minimum period for cataclysmic variables. The semi-analytic formulation has also been used to illustrate the importance of low mass, X-ray binaries as a means of determining the lower limit of the coupling constant of the Brans-Dicke theory of gravity. Detailed information concerning the structure of the secondary of close binary systems is calculated by means of a Henyey scheme. Tidal and rotational distortion has been included in the formulation and the evolution of a (1 + .75) M(,(CIRCLE)) binary system is studied both for the case of spherical symmetry and with the inclusion of distortional effects. A (.4 + 1) M(,(CIRCLE)) system is evolved past the point of minimum period. Good agreement is found between the theoretical value and the observed period cut-off. As well, we find that ignoring the effects of distortion can lead to a significant theoretical underestimate of the value of the minimum period.

Nelson, Lorne Archie

1984-09-01

158

Relation of various degrees of body mass index in patients with systemic hypertension to left ventricular mass, cardiac output, and peripheral resistance (The Hypertension Genetic Epidemiology Network Study)  

Microsoft Academic Search

The impact of different methods of indexation of left ventricular (LV) mass and systemic hemodynamic variables on prevalences and correlates of cardiovascular abnormalities in relation to level of obesity in populations remains unclear. We evaluated 1,672 participants in the Hypertension Genetic Epidemiology Network Study to investigate the relations of overweight and level of obesity to LV mass and prevalences of

Vittorio Palmieri; Giovanni de Simone; Donna K Arnett; Jonathan N Bella; Dalane W Kitzman; Albert Oberman; Paul N Hopkins; Michael A Province; Richard B Devereux

2001-01-01

159

Variable emissivity laser thermal control system  

DOEpatents

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.

Milner, Joseph R. (Livermore, CA)

1994-01-01

160

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

PubMed

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

Pahnke, Katharina; Zahn, Rainer

2005-03-18

161

Direct measurement of subsurface mass change using the variable baseline gravity gradient method  

NASA Astrophysics Data System (ADS)

gravity data provide a direct, nondestructive method to monitor mass changes at scales from centimeter to kilometer. 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 changes. 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, noninvasive measurement of infiltration wetting front velocity and change in water content above the wetting front.

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

2014-04-01

162

A variable-collimation display system  

NASA Astrophysics Data System (ADS)

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.

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

2014-03-01

163

Control system for a continuously variable transmission  

SciTech Connect

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.

Vahabzadeh, H.

1986-08-26

164

Evaluation of Small Mass Spectrometer Systems  

NASA Technical Reports Server (NTRS)

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.

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

165

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

166

Applications of internal translating mass technologies to smart weapons systems  

NASA Astrophysics Data System (ADS)

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.

Rogers, Jonathan

167

Variable Structure Control System Applied to Multilevel Power Conditioning Converters.  

National Technical Information Service (NTIS)

A control technique devised to obtain high dynamic responses from a multilevel power conditioning converter is presented. A variable structure system with sliding mode is followed, taking into account problems that may be encountered in space environments...

D. Casini M. Marchesoni L. Puglisi

1989-01-01

168

Variable frequency drives-application to ships propulsion systems  

Microsoft Academic Search

A basic outline of some of the many challenges that are presented in ships propulsion systems for the integration of variable speed drives with the new technology propulsion motors such as permanent magnet motors, superconductor motors and homopolar motors.

M. J. V. Wimshurst

2002-01-01

169

Solving Systems of Linear Equations in Two Variables  

NSDL National Science Digital Library

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

170

Variable emissivity laser thermal control system  

DOEpatents

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.

Milner, J.R.

1994-10-25

171

Modified rock mass classification system by continuous rating  

Microsoft Academic Search

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

Zekai ?en; Bahaaeldin H. Sadagah

2003-01-01

172

Geotechnical description and JGS engineering classification system for rock mass  

Microsoft Academic Search

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

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

2005-01-01

173

Variability in the 2MASS calibration fields: a search for transient obscuration events  

NASA Astrophysics Data System (ADS)

We searched the light curves of over 40 000 stars in the Two Micron All Sky Survey (2MASS) calibration data base, spanning approximately 4 yr, for objects that have significant day-long dimming events. We also searched the multi-colour light curves for red-dimming events that could be due to transient extinction. In the colour-independent sigma-limited search, we found 46 previously unrecognized eclipsing binaries, 6 previously unrecognized periodic variable stars likely to be intrinsic pulsators and 21 young stellar objects in the ? Ophiuchus star formation region previously studied by Parks et al. An additional 11 objects exhibited dimming events, and most of these are unclassified. The search for red-dimming events primarily reveals a population of low-luminosity active galaxies that become bluer when they are brighter, and variable young stellar objects exhibiting high cross-correlation coefficients between colour and brightness. The young stellar objects primarily exhibit brightness and colour variations in the direction of interstellar extinction whereas the active galaxies can have a bowed distribution in colour and magnitude with reduced variation in colour when the object is brightest. Among the objects that are usually quiescent (not strongly variable), we failed to find any dimming events deeper than 0.2 mag and lasting longer than a day. Two of the young stellar objects, however, dimmed by 0.2 mag for longer than a day without strong colour variation.

Quillen, Alice C.; Ciocca, Marco; Carlin, Jeffrey L.; Bell, Cameron P. M.; Meng, Zeyang

2014-07-01

174

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

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

175

The rotating drum dustiness tester: Variability in dustiness in relation to sample mass, testing time, and surface adhesion  

Microsoft Academic Search

A rotating drum dustiness tester was used to characterize variability of dustiness in dependence of type and mass of test material, testing time, and surface adhesion. Powders of six common materials entered the study: bentonite, barium sulphate, talc, Aloxite, carbon black, and coal. Except for coal, dustiness was in general positively correlated to the mass of powder under testing. Surface

N. O. Breum

1999-01-01

176

Fractal variability: An emergent property of complex dissipative systems  

NASA Astrophysics Data System (ADS)

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.

Seely, Andrew J. E.; Macklem, Peter

2012-03-01

177

Mass Transfer and Tidal Dynamics in White Dwarf Binary Systems  

NASA Astrophysics Data System (ADS)

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.

Gerber, Jeffrey; Fuller, J.

2014-01-01

178

Modeling the spatial variability of dispersivity to deal with anomalous mass transport in the subsurface  

NASA Astrophysics Data System (ADS)

The limitations of the classical Advection-Dispersion Equation (ADE) approach to model mass transport remain a subject of research. The term anomalous transport is usually applied when the ADE fails to reproduce real field or lab experiments tracer tests data. Some authors address this limitation using high-resolution heterogeneous hydraulic conductivity (K) fields. Besides, the non-Fickian behavior of transport is another issue addressed. However, the effects of the spatial variability of dispersivity, and the influence of the model support scale on this property, have been rarely studied. The lack of experimental knowledge on the dispersivity behavior leads to model this basic parameter as an averaged calibrated parameter highly dependent on the model discretization size. In order to study the local behavior of the dispersivity a porous medium tank was designed and built at the Technical University of Valencia (Spain). This paper presents new results and conclusions obtained from the experiments conducted in this lab prototype. The steady flow through the porous medium tank lab is quasi-2D, and the K field imitates the patterns of spatial variability found in a real and highly heterogeneous formation (MADE2 site). The tracer tests are run using a conservative dye tracer and the tank is monitored by a grid of pressure transducers and taking digital images that are processed to map the evolution of solute concentrations in the tank. The set of exhaustive head and concentration data is used to compute detail local information of the effective dispersivity field at different time steps, and at different support scales. The analysis of results shows that the dispersivity field displays patterns of spatial variability related with the physical nature of the local material and also with the local evolution of concentrations at every grid block. We have found that the anomalous transport behavior observed in the lab tank can be accurately modeled using the classical ADE if the dispersivity field identified from the lab measurements is used. However, we have also obtained high-resolution K fields by inverse stochastic modeling, and have been able to reproduce experimental data using these K fields with average dispersivity data. This result apparently shows there are to alternative approaches based on the spatial variability of K field or dispersivity field. It happens that mathematically the latter parameter might be derived from the variability of K. However, we show the convenience of modeling both dispersivity and K variability.

Capilla, J. E.; Sanchez Fuster, I.; Sanchez Barrero, L.

2012-12-01

179

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

NASA Astrophysics Data System (ADS)

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

Winguth, Arne; Winguth, Cornelia

2013-06-01

180

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

NASA Astrophysics Data System (ADS)

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.

Carton, X.; L'Hegaret, P.

2011-06-01

181

Variability of Mass Dependence of Auroral Acceleration Processes with Solar Activity  

NASA Technical Reports Server (NTRS)

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.

Ghielmetti, Arthur G.

1997-01-01

182

Design of variable structure model-following control systems  

Microsoft Academic Search

A new design concept for adaptive model-following control systems capable of shaping the error transient responses is developed using the theory of variable structure systems and sliding mode. It is shown that the resulting model-following control system exhibits adaptive properties inherent in adaptive model-following systems designed by existing methods. An aircraft control problem which has been approached using various model-following

KAR-KEUNG D. YOUNG

1978-01-01

183

Untangling complex dynamical systems via derivative-variable correlations.  

PubMed

Inferring the internal interaction patterns of a complex dynamical system is a challenging problem. Traditional methods often rely on examining the correlations among the dynamical units. However, in systems such as transcription networks, one unit's variable is also correlated with the rate of change of another unit's variable. Inspired by this, we introduce the concept of derivative-variable correlation, and use it to design a new method of reconstructing complex systems (networks) from dynamical time series. Using a tunable observable as a parameter, the reconstruction of any system with known interaction functions is formulated via a simple matrix equation. We suggest a procedure aimed at optimizing the reconstruction from the time series of length comparable to the characteristic dynamical time scale. Our method also provides a reliable precision estimate. We illustrate the method's implementation via elementary dynamical models, and demonstrate its robustness to both model error and observation error. PMID:24848769

Levnaji, Zoran; Pikovsky, Arkady

2014-01-01

184

Untangling complex dynamical systems via derivative-variable correlations  

PubMed Central

Inferring the internal interaction patterns of a complex dynamical system is a challenging problem. Traditional methods often rely on examining the correlations among the dynamical units. However, in systems such as transcription networks, one unit's variable is also correlated with the rate of change of another unit's variable. Inspired by this, we introduce the concept of derivative-variable correlation, and use it to design a new method of reconstructing complex systems (networks) from dynamical time series. Using a tunable observable as a parameter, the reconstruction of any system with known interaction functions is formulated via a simple matrix equation. We suggest a procedure aimed at optimizing the reconstruction from the time series of length comparable to the characteristic dynamical time scale. Our method also provides a reliable precision estimate. We illustrate the method's implementation via elementary dynamical models, and demonstrate its robustness to both model error and observation error.

Levnaji, Zoran; Pikovsky, Arkady

2014-01-01

185

Mass Properties Measurement System: Dynamics and Statics Measurements.  

National Technical Information Service (NTIS)

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 ...

K. L. Doty

1993-01-01

186

Source related state variables for the carbon system  

NASA Astrophysics Data System (ADS)

The oceanic carbon system is by tradition described in terms of total carbon, DIC, and alkalinity, Alk. Furthermore the usual way to define alkalinity is confusing and unnecessarily complicated beeing related to a measuring procedure rather than to the actual supply of material to the system. Here we propose an alternativ straightforward way to define alkalinity. We also define alternative source-adapted state variables which represent respectively the supply to the system of carbondioxid and disolved carbonate. These variables then tell us how much carbondioxid or carbonate we actually have in the water despite the fact that the major part of the carbon recides in bicarbonate ions. We claim that using these "source-related variables" offer a number advantages, e.g. in the interpretation of observations as well as modelling results.

Walin, G.; Hedvall, J.; Nycander, J.

2012-12-01

187

Hybrid orthosis system with a variable hip coupling mechanism.  

PubMed

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

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

2006-01-01

188

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

PubMed

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

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

2009-08-01

189

Numerical simulation of a variable speed refrigeration system  

Microsoft Academic Search

This work presents two numerical models to simulate the transient and steady state behavior of a vapor compression refrigeration system. The condenser and the evaporator were divided into a number of control volumes. Time dependent partial differential equations system was obtained from the mass, energy and momentum balances for each control volume. As the expansion valve and the compressor both

R. N. N. Koury; L. Machado; K. A. R. Ismail

2001-01-01

190

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

PubMed

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

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

2010-01-01

191

Seasonal variability of black carbon mass in the tropical tropopause layer  

NASA Astrophysics Data System (ADS)

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.

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

2011-05-01

192

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

USGS Publications Warehouse

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.

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

2014-01-01

193

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

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

194

Power optimization of variable voltage core-based systems  

Microsoft Academic Search

The growing class of portable systems, such as personal computing and communication devices, has resulted in a new set of system design requirements, mainly characterized by dominant importance of power minimization and design reuse. We develop the design methodology for the low power core-based real-time system-on-chip based on dynamically variable voltage hardware. The key challenge is to develop effective scheduling

Inki Hong; Darko Kirovski; Gang Qu; Miodrag Potkonjak; Mani B. Srivastava

1998-01-01

195

Power smoothing in a variable speed wind-diesel system  

Microsoft Academic Search

In wind-diesel systems wind speed variations can produce frequent start\\/stop cycles of the diesel engine in response to periods of low wind speed. Consequently, an energy buffer is very important in these schemes to avoid unnecessary deterioration of the diesel engine. In this paper, control systems for the operation of a variable speed wind-diesel system, including power smoothing, are analyzed.

R. Cardenas; R. Pena; Jon Clare; G. Asher

2003-01-01

196

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 Astrophysics Data System (ADS)

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 (? = 550 nm) 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 sulfate, nitrate, and elemental carbon. Achieving full optical closure is hampered by limitations in accounting for the role of water vapor in the system, uncertainties in the instruments and the need for further knowledge in the source apportionment of the model's major chemical components. Nonetheless, 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 sulfate 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. 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.

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

2013-10-01

197

Solving Systems of Linear Equations in Two Variables  

NSDL National Science Digital Library

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

Seward, Kim; Puckett, Jennifer

2008-01-01

198

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

NASA Astrophysics Data System (ADS)

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.

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

2012-03-01

199

Parallel operation of variable speed pumps in chilled water systems  

SciTech Connect

In the last two to three decades the cost of variable speed devices has come down considerably and their energy consumption has improved to the point that they no longer waste energy. Additionally, speed control of the circulating pumps in variable volume flow hydronic systems permits matching the head generated by the pumps to the frictional resistance to flow in the system. This will improve the operation of the control valves and save energy. In view of these advantages, the use of variable speed pumps has become widespread. Nevertheless, the speed control devices are costly, and the question arises whether all pumps in a given installation need be equipped with them. This article will explore the interaction between multiple speed pumps operating in parallel and their interface with the hydronic system they serve. It will specifically address two questions: can one pump be operated at varying speed in parallel with another pump at fixed speed? Also, what is the most economical method of applying variable speed pumping in a given chilled water system? It will be seen that the benefits to be gained from unequal speed operation of parallel pumps are minimal and the benefits are outweighed by the danger inherent in such operation. This practice must be discouraged. The study also will show that in a correctly engineered and analyzed system the number of parallel pumps can be reduced and that not all need be provided with speed control. However, all pumps in parallel operation must be run at the same speed.

Hansen, E.G.

1995-10-01

200

Confirmation of mass-independent Ni isotopic variability in iron meteorites  

NASA Astrophysics Data System (ADS)

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 ?60Ni,?62Ni and ?64Ni, 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 ?60Ni, ?62Ni and ?64Ni, 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 ?60Ni, ?62Ni and ?64Ni of -0.006?, 0.036? and 0.119?, respectively. There is a strong positive correlation between ?64Ni and ?62Ni 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.

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

2011-12-01

201

Study on Improvement of Odor Recording Capability Based on Real-time Mass Spectrometry with Variable Ionization Energy  

NASA Astrophysics Data System (ADS)

An odor recorder is a system to record the odors as well as reproduce them. In order to record a wide range of odors, a number of available odor components are required in the odor recorder. Moreover, the sufficient pattern separation among all odor components is also required to avoid a collinearity problem caused by the lack of the pattern separation among odor components. In this study, we proposed an odor recorder based on real-time mass spectrometry with variable ionization energy in order to improve odor recording capability. In this system, the higher-order sensing capability due to the different ionization energies can be achieved. It was found that the enriched data obtained from this system could be used to improve the pattern separation among odor components. Moreover, the recipe of the target odor was more accurately estimated based on combination of m/z's obtained from different ionization energies. Thus, this proposed system could be useful to improve the odor recording capability so that the recordable range of odor could be extended.

Somboon, Pakpum; Nakamoto, Takamichi

202

Variability of sea surface salinity in stochastically forced systems  

Microsoft Academic Search

The influences of horizontal advection and horizontal diffusion on the variability of sea surface salinity in stochastically forced systems are investigated. Basic ideas are developed using a two dimensional box model and then extended to a more realistic three dimensional ocean general circulation model. It is shown that, in the absence of advection and diffusion, the ocean response is essentially

Michael A. Spall

1993-01-01

203

Extremal entanglement and mixedness in continuous variable systems  

Microsoft Academic Search

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

Gerardo Adesso; Alessio Serafini; Fabrizio Illuminati

2004-01-01

204

Quantification and Scaling of Multipartite Entanglement in Continuous Variable Systems  

Microsoft Academic Search

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

Gerardo Adesso; Alessio Serafini; Fabrizio Illuminati

2004-01-01

205

Evolution of slow variables in a priori unstable Hamiltonian systems  

NASA Astrophysics Data System (ADS)

We study diffusion phenomena in a priori unstable (initially hyperbolic) Hamiltonian systems. These systems are perturbations of integrable ones, which have a family of hyperbolic tori. We prove that in the case of two and a half degrees of freedom the action variable generically drifts (i.e. changes on a trajectory by a quantity of order one). Moreover, there exists a trajectory such that the velocity of this drift is egr/logegr, where egr is the parameter of the perturbation.

Treschev, D.

2004-09-01

206

Variable-reluctance generators in wind-energy systems  

Microsoft Academic Search

Two methods of incorporating the variable-reluctance generator (VRG) into advanced wind conversion systems at or above the 50-kW power level are presented. Operating through a power electronic interface to the electric utility, this generator offers simplifications of the utility\\/generator interface over adjustable-speed wind conversion systems based on the induction generator. In addition, analyses performed using experimentally based data show that

David A. Torrey

1993-01-01

207

Variable structure control of discretized continuous-time systems  

Microsoft Academic Search

A discrete-time variable structure control technique is presented for uncertain continuous-time systems. The design algorithm makes use of the concept of time-delay control in order to estimate the effects of the system perturbations inside the switching region. The controller performances have been evaluated by simulation using a benchmark problem proposed in literature. A satisfactory behavior is obtained also in the

M. Letizia Corradini; Giuseppe Orlando

1998-01-01

208

Socio-demographic variables and 6 year change in body mass index: longitudinal results from the GLOBE study  

Microsoft Academic Search

Background: Body mass index (BMI) differs by socio-demographic variables, but the origin of these associations remains relatively unknown.Objective: To investigate the association between socio-demographic variables and the subsequent change in BMI over six years.Design: A Dutch prospective cohort study (GLOBE) from which data were used from initially 20–49-year-old subjects (males: n=362; females: n=405). BMI was calculated from self-reported body height

FJ van Lenthe; M Droomers; CTM Schrijvers; JP Mackenbach; Frank J van Lenthe

2000-01-01

209

Variable stiffness and damping suspension system for train  

NASA Astrophysics Data System (ADS)

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.

Sun, Shuaishuai; Deng, Huaxia; Li, Weihua

2014-03-01

210

Toda lattice mass transport in Lagrangian mechanics and in a two-dimensional system  

NASA Astrophysics Data System (ADS)

This paper explores the connection between the hydrodynamic mass transport description and the thermodynamic description for a nonlinear range of the Toda lattices. Particular attention is paid to the broken isotropy in the KdV and Burgers equations. The flow variable representation is established from the Lagrangian mechanics for hydrodynamic mass transport. Based on the inverse scattering transform, the Gel’fand-Levitan-Marchenko (GLM) equation is formulated from the KdV equation expressed by the flow variable representation. We found that a kernel of the GLM equation is given by the concentration variable Q(x,t). A Lagrangian is formulated for the KdV equation in state space (Q(x,t),K(x,t)). Next, an extension of the flow variable representation is sought in a two-dimensional system. The LHS of the Kadomtsev-Petviashvili (KP) equation takes the same form as in the second formalism of the KdV equation. By setting up the flow variable representation of the KP equation, the Burgers equation in two dimensions is formulated. These results contribute to an understanding of the broken isotropy for the nonlinear mass transport equations. These results provide physical insight into various consequences of the generalized form of the Kawasaki-Ohta equation from the viewpoint of mass transport.

Horii, Zene

2006-03-01

211

Modeling Mass in the Solar System and a Galaxy  

NSDL National Science Digital Library

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

212

Seasonal and interannual variability of glacier mass loss in southern Alaska  

NASA Astrophysics Data System (ADS)

Alaska's climate is changing and one of the most significant indications of this change has been the late 19th to early 21st century behavior of Alaskan glaciers. Over the last decade, Gravity Recovery and Climate Experiment (GRACE) gravity measurements have enabled estimates of regional ice loss trends in glaciated southern Alaska. However, higher-resolution in situ, aircraft, GPS and other satellite data are being used to study the basin-scale processes responsible for the observed broad-scale seasonal and inter-annual variability of GRACE-derived mass change. Specifically we report on the use Moderate-resolution Imaging Spectroradiometer (MODIS) Land Surface Temperature (LST) and Fractional Snow Cover (FSC) products, at a spatial scale of 1 km or less, to document the temporal and spatial evolution of seasonal processes over a time period that includes the GRACE observations (2002 to present). We use observations of cryospheric change over the last decade as input to 3-D viscoelastic Earth models of southern Alaska. In addition to glacial changes on a variety of temporal and spatial scales, southern Alaska is tectonically active with frequent large earthquakes. The gravimetric response, as well as the rate and orientation of crustal deformation, due to relaxation processes associated with inter-annual snow/ice changes, glacier wastage on time scales of years to decades, and large earthquakes (1964 Prince William Sound, M=9.2, 2002 Denali, Mw=7.9) will be discussed.

Sauber, J. M.; Hall, D. K.; Han, S.; Luthcke, S. B.

2013-12-01

213

Performance of Thermal Mass Flow Meters in a Variable Gravitational Environment  

NASA Technical Reports Server (NTRS)

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.

Brooker, John E.; Ruff, Gary A.

2004-01-01

214

Fermilab's Multi-Petabyte Scalable Mass Storage System  

Microsoft Academic Search

Fermilab provides a multi-Petabyte scale mass storage system for High Energy Physics (HEP) Experiments and other scientific endeavors. We describe the scalability aspects of the hardware and software architecture that were designed into the Mass Storage System to permit us to scale to multiple petabytes of storage capacity, manage tens of terabytes per day in data transfers, support hundreds of

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

2005-01-01

215

Lightcraft Project: Flight Technology for a Hypersonic Mass Transit System.  

National Technical Information Service (NTIS)

Rensselaer Polytechnic Institute has been developing transatmospheric 'Lightcraft' technology aimed at creating an efficient, economically affordable, hypersonic mass transportation system. The system utilizes laser-energized airbreathing engines to accel...

L. Myrabo K. Bouchard

1992-01-01

216

Engineering of quantum systems with variables in GF(pell)  

NASA Astrophysics Data System (ADS)

A system comprised of ell subsystems, each of which is described with variables in ?p, is considered. Position and momentum states in this ell-partite system can be labelled with elements in GF(pell). It is shown that the whole quantum formalism can be expressed in terms of Galois arithmetic, if and only if the Hamiltonian belongs to a particular subset of the set of all Hamiltonians of this ell-partite system (we say that these Hamiltonians are compatible with GF(plell)). Several examples of such Hamiltonians are presented.

Vourdas, A.

2011-03-01

217

Managing variability in the IO performance of petascale storage systems.  

SciTech Connect

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.

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

2010-11-01

218

Fan energy use in variable air volume systems  

SciTech Connect

Fan energy consumption in variable air volume (VAV) systems is affected by both the technique used to control the flow rate and the control algorithm used. In this paper a simulation study is made of a ''standard'' 10,000 square foot building. Three flow-control techniques- system dampers, inlet vane control, and variable speed control- are considered along with two types of control algorithms: proportional (P) and proportional-integral (PI). A relationship is derived for the relative power consumption under P and PI control. Fan power consumption in the example building is calculated for five locations, two types of fan (backward-inclined centrifugal and vaneaxial), the three control techniques, and the two control algorithms. Significant differences are found in annual energy consumption for the different cases.

Brothers, P.W.; Warren, M.L.

1986-01-01

219

Movement Systems as Dynamical Systems: The Functional Role of Variability and its Implications for Sports Medicine  

Microsoft Academic Search

successfully applied to the study of movement systems, contradicting traditional views of variability as noise or error. From this perspective, it is apparent that variability in movement systems is omnipresent and unavoidable due to the distinct constraints that shape each individual's behaviour. In this position paper, it is argued that trial-to-trial movement variations within individuals and perform- ance differences observed

Keith Davids; Paul Glazier; Roger Bartlett

2003-01-01

220

Mass enhancement in narrow-band systems  

Microsoft Academic Search

A perturbative study of the Holstein molecular crystal model which accounts for lattice structure and dimensionality effects is presented. Anti-adiabatic conditions peculiar to narrow-band materials and an intermediate-to-strong electron-phonon coupling are assumed. The polaron effective mass depends crucially in all dimensions on the intermolecular coupling strengths which also affect the size of the lattice deformation associated with the small-polaron formation.

Marco Zoli

2000-01-01

221

South Atlantic Multidecadal Variability in the Climate System Model  

Microsoft Academic Search

Strong multidecadal variability is detected in a 300-yr integration of the NCAR Climate System Model in the South Atlantic region, through the application of two signal recognition techniques: the multitaper method and singular spectrum analysis. Significant oscillations of a 25-30-yr period are found in the sea surface temperature, sea level pressure, and barotropic transport fields. A similar-scale signal is also

Ilana Wainer; Silvia A. Venegas

2002-01-01

222

A variable-rate filtering system for digital communications  

Microsoft Academic Search

We propose an efficient programmable transmit-receive digital filter structure consisting of a pulse shaping filter (PSF) and a cascaded integrator-comb (CIC) filter which is applicable to variable-rate digital communication systems. The CIC structure is a hardware-efficient means of constructing programmable interpolation and decimation filters, but it introduces a large amount of intersymbol interference (ISI). We solve this problem by proposing

L. Wasserman

1999-01-01

223

Quantification and scaling of multipartite entanglement in continuous variable systems.  

PubMed

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

Adesso, Gerardo; Serafini, Alessio; Illuminati, Fabrizio

2004-11-26

224

Variable geometry ejectors and their applications in ejector refrigeration systems  

Microsoft Academic Search

Refrigeration and air-conditioning units powered by low-grade thermal energy have economic advantages. However, the current market is dominated by mechanical vapour-compression systems powered by electrical energy. Ejector-refrigeration cycles offer a low-cost and reliable option for harnessing low-grade thermal energy. Recent studies have shown that variable-geometry ejectors play an important role in achieving optimal performance. Unfortunately, detailed design information on these

Da-Wen Sun

1996-01-01

225

MEASURING THE MASS OF SOLAR SYSTEM PLANETS USING PULSAR TIMING  

SciTech Connect

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.

Champion, D. J.; Hobbs, G. B.; Manchester, R. N.; Edwards, R. T.; Burke-Spolaor, S.; Sarkissian, J. M. [CSIRO Astronomy and Space Science, Australia Telescope National Facility, P.O. Box 76, Epping, NSW 1710 (Australia); Backer, D. C. [Department of Astronomy and Radio Astronomy Laboratory, University of California, Berkeley, CA 94720 (United States); Bailes, M.; Bhat, N. D. R.; Van Straten, W. [Swinburne University of Technology, P.O. Box 218, Hawthorn, Victoria 3122 (Australia); Coles, W. [Electrical and Computer Engineering, University of California at San Diego, La Jolla, CA (United States); Demorest, P. B. [National Radio Astronomy Observatory, Charlottesville, VA 22901 (United States); Ferdman, R. D.; Purver, M. B. [Jodrell Bank Centre for Astrophysics, University of Manchester, Manchester M13 9PL (United Kingdom); Folkner, W. M. [Jet Propulsion Laboratory, 4800 Oak Grove Dr, Pasadena, CA 91109-8099 (United States); Hotan, A. W. [Curtin Institute of Radio Astronomy, Curtin University, Bentley, WA 6102 (Australia); Kramer, M. [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, 53121 Bonn (Germany); Lommen, A. N. [Franklin and Marshall College, 415 Harrisburg Pike, Lancaster, PA 17604 (United States); Nice, D. J. [Physics Department, Lafayette College, Easton, PA 18042 (United States); Stairs, I. H., E-mail: champion@pulsarastronomy.ne [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada)

2010-09-10

226

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)

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.

Johnson, Z. I.; Hunt, D.

2013-12-01

227

Separation of variables in an asymmetric cyclidic coordinate system  

NASA Astrophysics Data System (ADS)

A global analysis is presented of solutions for Laplace's equation on three-dimensional Euclidean space in one of the most general orthogonal asymmetric confocal cyclidic coordinate systems which admit solutions through separation of variables. We refer to this coordinate system as five-cyclide coordinates since the coordinate surfaces are given by two cyclides of genus zero which represent inversions of each other with respect to the unit sphere, a cyclide of genus one, and two disconnected cyclides of genus zero. This coordinate system is obtained by stereographic projection of sphero-conal coordinates on four-dimensional Euclidean space. The harmonics in this coordinate system are given by products of solutions of second-order Fuchsian ordinary differential equations with five elementary singularities. The Dirichlet problem for the global harmonics in this coordinate system is solved using multiparameter spectral theory in the regions bounded by the asymmetric confocal cyclidic coordinate surfaces.

Cohl, H. S.; Volkmer, H.

2013-06-01

228

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

PubMed Central

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.

Kumar, D.; Jaiswal, R. K.

2005-01-01

229

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

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

230

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

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

231

Measures of Quantum Synchronization in Continuous Variable Systems  

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

232

Polychannel systems for mass digital communication  

NASA Astrophysics Data System (ADS)

We describe a new type of distributed computer system that looks beyond workstation and local area network assumptions towards the time when computers will be used by everyone at both home and the office. This new system is designed to provide sophisticated information services to an entire metropolitan area. We have combined digital broadcast channels and duplex communication channels in a polychannel system that uses predicate based database content labels to automatically route queries. Our thesis is that a polychannel system produces substantial cost and system scaling advantages while retaining the flexibility of client-server style duplex communication. Experimental data from a two year test of the Boson Community Information System system with hundreds of users supports this thesis.

Gifford, David K.

1988-07-01

233

Masses and ages of Delta Scuti stars in eclipsing binary systems  

NASA Astrophysics Data System (ADS)

By using data mainly from Frolov et al. (1982) for four Delta Scuti stars in eclipsing binary systems, AB Cas, Y Cam, RS Cha, and AI Hya, their physical parameters, distances, and radial pulsation modes are determined. The evolutionary track systems of Iben (1967), Paczynski (1970), and Maeder and Meynet (1988) are interpolated in order to estimate evolutionary masses Me and ages t of these variables. Their pulsation masses MQ are estimated from the fitting formulae of Faulkner (1977) and Fitch (1981). Our estimates of evolutionary masses M(e) and pulsation masses M(Q) are close to the masses M determined by Frolov et al. from the star binarity. The only exception is AB Cas, for which there is no agreement between certain star parameters. Another, independent approach is also applied to the stars RS Cha and AI Hya: by using their photometric indices b - y and c(1) from the catalog of Lopez de Coca et al. (1990) and appropriate photometric calibrations, other sets of physical parameters, distances, modes, ages, and evolutionary and pulsation masses of both variables are obtained.

Tsvetkov, Ts. G.; Petrova, Ts. C.

1993-05-01

234

Synchronization in networked mass-spring-damper oscillator systems  

Microsoft Academic Search

This brief paper considers synchronization dynamics in networked mass-spring-damper (MSD) oscillator systems with nonlinear spring interaction. Based on stability theory on dynamical system, algebraic graph theory, and some matrix theory, an exact solution of synchronization state for such networked oscillator systems is derived analytically. It is shown that the networked MSD oscillator systems can be synchronized to a simple harmonic

Shan Cheng; Lan Xiang; Jin Zhou

2010-01-01

235

Compressive mass analysis on quadrupole ion trap systems.  

PubMed

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

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

2014-07-01

236

Compressive Mass Analysis on Quadrupole Ion Trap Systems  

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

237

Extremal entanglement and mixedness in continuous variable systems  

SciTech Connect

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.

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

2004-08-01

238

Balloon borne optical disk mass storage system  

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

239

Low-Mass Inflation Systems for Inflatable Structures  

NASA Technical Reports Server (NTRS)

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.

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

1995-01-01

240

Two-Stage Variable Sample-Rate Conversion System  

NASA Technical Reports Server (NTRS)

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.

Tkacenko, Andre

2009-01-01

241

Realtime Multichannel System for Beat to Beat QT Interval Variability  

NASA Technical Reports Server (NTRS)

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.

Starc, Vito; Schlegel, Todd T.

2006-01-01

242

Effects of correlated variability on information entropies in nonextensive systems  

NASA Astrophysics Data System (ADS)

We have calculated the Tsallis entropy and Fisher information matrix (entropy) of spatially correlated nonextensive systems, by using an analytic non-Gaussian distribution obtained by the maximum entropy method. The effects of the correlated variability on the Fisher information matrix are shown to be different from those on the Tsallis entropy. The Fisher information is increased (decreased) by a positive (negative) correlation, whereas the Tsallis entropy is decreased with increasing absolute magnitude of the correlation, independently of its sign. This fact arises from the difference in their characteristics. It implies from the Cramér-Rao inequality that the accuracy of an unbiased estimate of fluctuation is improved by a negative correlation. A critical comparison is made between the present study and previous ones employing the Gaussian approximation for the correlated variability due to multiplicative noise.

Hasegawa, Hideo

2008-08-01

243

Modular sampling and inlet systems for mobile environmental mass spectrometry  

Microsoft Academic Search

Sampling systems and gas Chromatographic separators based on a modular concept have been developed for a mobile\\/portable quadrupole mass spectrometer. A special quick connector, designed to easily mount and remove the gas Chromatograph from the mass spectrometer, allows the operator to switch between different GC modules within minutes. A polysiloxane inlet membrane seals the vacuum chamber and prevents it from

Gökhan Baykut

1995-01-01

244

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...

245

Mass properties measurement system: Dynamics and statics measurements  

NASA Technical Reports Server (NTRS)

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.

Doty, Keith L.

1993-01-01

246

Solitary choroidal mass as the presenting sign in systemic sarcoidosis.  

PubMed Central

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

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

1983-01-01

247

A Collaborative Control System for Mass Customization Manufacturing  

Microsoft Academic Search

Mass Customization aims at producing customized products to meet individual customer's needs with mass production efficiency. The advent of this new mode of manufacturing introduces a different set of requirements on system control for manufacturing operations. The implications include the drastic increase of varieties, very small batch size, random arrival of orders, and wide spread of due dates. In addition,

Mitchell M. Tseng; Ming Lei; Chuanjun Su; M. Eugene Merchant

1997-01-01

248

Key Metrics System for Variety Steering in Mass Customization  

Microsoft Academic Search

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

Thorsten Blecker; Nizar Abdelkafi; Bernd Kaluza; Gerhard Friedrich

2003-01-01

249

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

PubMed Central

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.

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

2010-01-01

250

NASA Langley Research Center's distributed mass storage system  

NASA Technical Reports Server (NTRS)

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.

Pao, Juliet Z.; Humes, D. Creig

1993-01-01

251

Mass Storage System Reference Model, Version 4.  

National Technical Information Service (NTIS)

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...

S. Coleman S. Miller

1993-01-01

252

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

ERIC Educational Resources Information Center

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

Nigro, George A.

253

Mass Properties Test Procedure for Manikin Headforms and Helmet Systems.  

National Technical Information Service (NTIS)

The mathematical modeling and comparison of manikin headforms and helmet systems requires that the mass properties be accurately determined. The specific properties that must be known are the weight, center of gravity location, magnitudes of the principal...

J. M. Thornton D. J. Zaborowski

1992-01-01

254

Design of a variable-focal-length optical system  

NASA Technical Reports Server (NTRS)

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.

Ricks, D.; Shannon, R. R.

1984-01-01

255

Effect of perturbations on the stability of triangular points in the restricted problem of three bodies with variable mass  

NASA Astrophysics Data System (ADS)

The effect of small perturbations ? and ?arcmin in the coriolis and the centrifugal forces respectively on the stability of the triangular points in the restricted problem of three bodies with variable mass has been studied. It is found that the range of stability of triangular points increases or decreases depending upon whether the perturbation point (?, ?arcmin) lies in one or the other of the two parts in which the (?, ?arcmin) plane is divided by the line J8?-J9?arcmin = 0 where J8 and J9 depend upon ?, the constant due to the variation in mass governed by Jeans' law.

Singh, J.; Ishwar, B.

1985-03-01

256

Variable speed, condensing steam turbine and power system  

SciTech Connect

The variable speed condensing steam turbine is a simplified and effective steam expander which is built mainly of simple, lowcost sheet metal parts and is designed to provide a variable speed/torque output range. The turbine concept is based on the past tesla turbine principle of equally spaced rotor discs to provide a long helical path for steam expansion with high operating efficiency and minimum friction. Unlike the cylindrical tesla turbine this unit is in conical form with uniformly varying diameter discs used to provide a variable speed/torque power output range. A further purpose of having a uniform conical housing and uniformly increasing diameter discs is to achieve maximum steam expansion which will lead to rapid steam condensation, or a precondensation condition for the expended steam passing through the conical turbine. A fuel conservation feature of the condensing turbine is a provision for separating hydrogen gas from a portion of the expanded/expended steam which will be conducted to the external fuel burner of the vapor generator, as part of the complete power system.

Kelly, D.A.

1980-09-30

257

Photopolymer-based holographic variable data storage system for security applications  

NASA Astrophysics Data System (ADS)

Photopolymer based microholograms are gaining much importance in the field of security imaging, product authentication and prevention of document forgery. Security holograms, mass produced through soft or hard embossing, from electroformed metal master holograms are not amenable to store and retrieve variable data. On the other side, rapid developments in optical and digital technologies result in large scale counterfeiting of conventional security holograms and look-alike holograms of great exactitude is becoming a real threat to original manufacturers. In contrast to conventional recording materials, photopolymer holograms do not need wet processing. They are amenable to replication and, at the same time, can hold variable data. This, apart from security at various levels, facilitates machine readability, automation, easy tracking and effective maintenance of inventory. This paper presents design, development and performance evaluation of a photopolymer based holographic variable data storage system for security applications. A liquid crystal spatial light modulator (SLM) is used to create a modulated optical data beam that varies from hologram to hologram. Photopolymer films in tape form are applied for continuous recording of micro-holograms, synchronous with the variable data content. This is a novel, but simple data storage system and can be used to give added security, in conjunction with conventional holograms. Easy and on site verification by applying special reading devices and dedicated software is the other charm of the proposed system. Moreover, for added protection, variable key based data encryption can be applied effectively. System parameters like diffraction efficiency, recording speed, preprocessing requirements etc. are analyzed and the response of the photopolymer material is also evaluated.

Sheeja, M. K.; Ajith Kumar, P. T.; Achuthsankar, S. Nair

2006-10-01

258

Small system for tritium accelerator mass spectrometry  

DOEpatents

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.

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

1993-01-01

259

Small system for tritium accelerator mass spectrometry  

DOEpatents

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.

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

1993-02-23

260

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

NASA Astrophysics Data System (ADS)

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

Plastino, Angel R.; Muzzio, Juan C.

1992-09-01

261

A Conversational Mass Spectral Search System. IV. The Evolution of a System for the Retrieval of Mass Spectral Information  

ERIC Educational Resources Information Center

A prototype of an interactive, conversational mass spectral search system, developed at the National Institutes of Health, has been tested since September 1971 and is now being used by more than 200 scientists in the U.S. and Canada, and will soon be used by the international mass spectrometry community. (17 references) (SJ)

Heller, Stephen R.; And Others

1973-01-01

262

Thermal performance analysis of vacuum variable-temperature blackbody system  

NASA Astrophysics Data System (ADS)

In this paper, the design and structure of a vacuum variable-temperature blackbody system were described, and the steady-state thermal analysis of a 3-D blackbody model was presented. Also, the thermal performance of the blackbody was evaluated using an infrared camera system. The blackbody system was constructed to operate under vacuum conditions (2.67 × 10?2 Pa) to reduce its temperature uncertainty, which can be caused by vapor condensation at low temperatures usually below 273.15 K. A heat sink and heat shield including a cold shield were embedded around the radiator to maintain the heat balance of the blackbody. A simplified 3-D model of the blackbody including a radiator, heat sink, heat shield, cold shield, and heat source was thermophysically evaluated by performing finite elements analysis using the extended Stefan–Boltzmann's rule, and the infrared radiating performance of the developed system was analyzed using an infrared camera system. On the basis of the results of measurements and simulations, we expect that the suggested blackbody system can serve as a highly stable reference source for the calibration and measurement of infrared optical systems within operational temperature ranges.

Lee, Sang-Yong; Kim, Geon-Hee; Lee, Young-Shin; Kim, Ghiseok

2014-05-01

263

Effect of perturbation on the location of equilibrium points in the restricted problem of three bodies with variable mass  

NASA Astrophysics Data System (ADS)

The effect of small perturbations in the coriolis and the centrifugal forces on the location of equilibrium points in the restricted problem of three bodies with variable mass has been studied. It is found that the points L4 and L5 form nearly equilateral triangles with the primaries and the points L1, L2, L3 remain collinear and lie on the line joining the primaries.

Singh, J.; Ishwar, B.

1984-04-01

264

Determination of intratest variability of trace elements in foraminifera by laser ablation inductively coupled plasma-mass spectrometry  

Microsoft Academic Search

We have developed a technique to determine the variability of trace elements (including Li, B, Na, Mg, Mn, Cu, Zn, Sr and Ba) within foraminifera tests using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). This technique has a high spatial resolution (width 40–80 ?m, depth >0.5 ?m), is reproducible (<8% external reproducibility) and has low detection limits (generally <0.05

E. C. Hathorne; O. Alard; R. H. James; N. W. Rogers

2003-01-01

265

Determination of intratest variability of trace elements in foraminifera by laser ablation inductively coupled plasma-mass spectrometry  

Microsoft Academic Search

We have developed a technique to determine the variability of trace elements (including Li, B, Na, Mg, Mn, Cu, Zn, Sr and Ba) within foraminifera tests using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). This technique has a high spatial resolution (width 40-80 mum, depth >0.5 mum), is reproducible (<8% external reproducibility) and has low detection limits (generally <0.05

E. C. Hathorne; O. Alard; R. H. James; N. W. Rogers

2003-01-01

266

Dynamical Equations, Invariants and Spectrum Generating Algebras of Mechanical Systems with Position-Dependent Mass  

NASA Astrophysics Data System (ADS)

We analyze the dynamical equations obeyed by a classical system with position-dependent mass. It is shown that there is a non-conservative force quadratic in the velocity associated to the variable mass. We construct the Lagrangian and the Hamiltonian for this system and find the modifications required in the Euler-Lagrange and Hamilton's equations to reproduce the appropriate Newton's dynamical law. Since the Hamiltonian is not time invariant, we get a constant of motion suited to write the dynamical equations in the form of the Hamilton's ones. The time-dependent first integrals of motion are then obtained from the factorization of such a constant. A canonical transformation is found to map the variable mass equations to those of a constant mass. As particular cases, we recover some recent results for which the dependence of the mass on the position was already unnoticed, and find new solvable potentials of the Pöschl-Teller form which seem to be new. The latter are associated to either the su(1,1) or the su(2) Lie algebras depending on the sign of the Hamiltonian.

Cruz y Cruz, Sara; Rosas-Ortiz, Oscar

2013-01-01

267

Aerosol mass spectrometry systems and methods  

DOEpatents

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.

Fergenson, David P.; Gard, Eric E.

2013-08-20

268

Interactive segmentation of masses in digitized mammograms: observer variability and discriminative applications  

Microsoft Academic Search

This work presents a study on interactive segmentation of breast masses in digitized mammograms and on the analysis of shape parameters: compactness (C), contour moment-based shape parameter (M), and Fourier shape parameter (F). Digitized mammograms were selected for this study from The University of South Florida Digital Database for Screening Mammography (DDSM), containing 94 masses (46 benign and 48 malignant)

Esther Ristori; Francisco Sendra; Enrique Nava; Manuel Mart??nez-Morillo

2001-01-01

269

NCDC mass storage systems and technologies  

NASA Technical Reports Server (NTRS)

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

Davis, Dick

1993-01-01

270

Transmission ratio control system for a continuously variable transmission  

SciTech Connect

This patent describes a control system for a continuously variable transmission for transmitting the power of an internal combustion engine having a throttle valve to driving wheels of a motor vehicle through a clutch. The improvement in the system consists of: means for sensing operating conditions of the engine and for producing a corresponding first signal; means responsive to the first signal for determining a desired transmission ratio; means responsive to the desired transmission ratio for shifting the spool of the transmission ratio control valve so as to provide an actual transmission ratio of the transmission corresponding to the desired transmission ratio; means for detecting actual rapid deceleration of the vehicle above a predetermined value of rapid deceleration and producing a rapid deceleration signal when the actual rapid deceleration is above the predetermined value; and means responsive to the rapid deceleration signal for increasing the desired transmission ratio so as via the second means to increase the actual transmission ratio.

Ohkuma, H.

1989-02-14

271

Concepts for Variable/Multi-Speed Rotorcraft Drive System  

NASA Technical Reports Server (NTRS)

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.

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

2008-01-01

272

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

NASA Astrophysics Data System (ADS)

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). The dark hole system is the space-time center, and the dark matter-energy and dark planet (dark comet-asteroid) are around. Dark hole absorb the light (space-time), and radiate the dark mass-energy (mass-energy). So the dark mass-energy main make up of the negative proton and the negative neutron who can take negative density and negative pressure. The cosmological model is like ``Taiji'' model which is from Ancient China. The black hole (invisible stuff) has not a big mass and energy. The light can not leave off it, because it absorb the light. So it can cause the ``red-shift.'' Sun has a companion dark hole. When it recurrent visit solar system, it can take ``red-shift speeded up,'' and can take many dark comet-asteroids to impact near our earth. When the dark mass-energy go into the solar corona, The electron neutrinos can bombard the negative neutron and the negative proton, and take the a reaction with them. It's equation: n^-+ve -> p+?, p^-+ve -> n+?. Among it, n^-: the negative neutron, p^-: the negative proton, ve: the electron neutrino, p: the proton, n: the neutron, ?: the muon. We will use them to change the orbit of earth and dark comet for avoiding its impaction.

Cao, Dayong

2010-11-01

273

Adaptive mass expulsion attitude control system  

NASA Technical Reports Server (NTRS)

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.

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

2001-01-01

274

Mass Transfer with Chemical Reaction on Flow Past an Accelerated Vertical Plate with Variable Temperature and Thermal Radiation  

NASA Astrophysics Data System (ADS)

An exact solution of an unsteady radiative flow past a uniformly accelerated infinite vertical plate with variable temperature and mass diffusion is presented here, taking into account the homogeneous chemical reaction of first order. The plate temperature as well as concentration near the plate is raised linearly with time. The dimensionless governing equations are solved using the Laplace-transform technique. The velocity, temperature and concentration fields are studied for different physical parameters such as the thermal Grashof number, mass Grashof number, Schmidt number, Prandtl number, radiation parameter, chemical reaction parameter and time. It is observed that the velocity increases with increasing values of the thermal Grashof number or mass Grashof number. But the trend is just reversed with respect to the thermal radiation parameter. It is also observed that the velocity increases with the decreasing chemical reaction parameter

Muthucumaraswamy, R.; Balachandran, P.; Ganesan, K.

2013-08-01

275

High-Resolution Experimental Investigation of mass transfer enhancement by chemical oxidation from DNAPL entrapped in variable-aperture fractures  

NASA Astrophysics Data System (ADS)

Permanganate oxidation of DNAPL- contaminated fractured rock is an effective remediation technology. Permanganate ion reacts with dissolved DNAPL in a bi-molecular oxidation-reduction reaction. The consumption of dissolved DNAPL in this reaction results in increased concentration gradients away from the free-phase DNAPL, resulting in reaction-enhanced mass transfer, which accelerates contaminant removal. The specific objective of our research was to perform high-resolution non-intrusive experimental studies of permanganate oxidation in a 15.24 × 15.24 cm, transparent, analog, variable-aperture fracture with complex initial TCE entrapped phase geometry. Our experimental system uses light-transmission techniques to accurately measure both fracture aperture and the evolution of individual entrapped DNAPL blobs during the remediation experiments at high resolution (pixel size : 6.2×10-3 cm). Three experiments were performed with different flow rates and permanganate inflow concentrations to observe DNAPL-permanganate interactions across a broader range of conditions. Prior to initiating each experiment, the aperture field within the fracture was measured. The oxidation experiment was initiated by TCE injection into the water saturated fracture till the TCE reached the outflow end, followed by water re-injection through the fracture. The flowing water mobilized some TCE. We continued injection of water till TCE mobilization ceased, leaving behind the residual TCE entrapped within the variable-aperture fracture. Subsequently, permanganate injection through the fracture resulted in propagation of a fingered reaction front into the fracture. We developed image processing algorithms to analyze the evolution of DNAPL phase geometry over the duration of the experiment. The permanganate consumption rate varied significantly within the fracture due to the complex flow and DNAPL concentration fields. Precipitated MnO2 was clearly evident on the downstream side of DNAPL blobs near the inflow boundary indicating high reaction rates in these regions. This behavior is explained by the diversion of permanganate around entrapped DNAPL blobs and downstream advection of dissolved DNAPL. Our results indicate that the total rate of mass transfer from the DNAPL blobs is higher at early times, when not much MnO2 has formed and precipitated. With time, MnO2 precipitation in the fracture leads to changes the aperture field and flow field. Precipitated MnO2 around TCE blobs also decreases the DNAPL accessible surface area. By comparing the results of three experiments, we conclude that low permanganate concentrations and high flow rates lead to more efficient DNAPL remediation, resulting from the fact that under these conditions there would be slower MnO2 formation and less precipitation within the fracture. We also present results on the time-evolution of fracture-scale permanganate consumption and DNAPL removal rates. The experimental observations are being used to develop improved high-resolution numerical models of reactive transport in variable-aperture fractures. The overall goal is to relate the coupled processes of DNAPL removal, permanganate consumption, MnO2 formation and associated changes in aperture and interface area; to derive fracture-scale effective representations of these processes.

Arshadi, M.; Rajaram, H.; Detwiler, R. L.; Jones, T.

2012-12-01

276

Masses of Early-type contact binary systems  

NASA Astrophysics Data System (ADS)

In general, the mass ratio derived from photometric analyses, q(pe), agrees quite well with the value derived from double-line spectroscopic binary, q(sp), for wide pairs as well as for the close pairs. Therefore one wishes that masses could be determined for single-line systems with the help of photometric mass ratio. It is believed that the large masses determined for early type contact systems may be not reliable or quite wrong due to misleading photometric solution, mass ratios. Of course this includes some of my old published papers as well. The appearance of continuous light variation of their light curves resembles a system with contact configuration. In general, the temperature difference between the components is relatively well determined from the differential depths of the eclipses. Most of these systems have large temperature differences. In mode 3 (most popular) contact configuration of W-D method would automatically ends up with a very large temperature discontinuity at the interface. Even though some of our (with D. Q. Zhou of Peking University) model calculations on circulation in contact atmosphere did arrive at stable flow. (The mathematics just becomes too difficult to handle.) One can easily argue that such temperature discontinuity in a system can not be stable. If one utilizes the mode 1 configuration of the W-D method, there would not be a temperature discontinuity at the interface but than the temperature difference derived would not agree with the differential depths of eclipses. The key problem comes from the fact that there is only very slight difference in the shape of the light curves between a contact system and a very close semidetached system. Essentially there is no inflection point in the contact light curve while there is a slight inflection point for the latter. Since we are dealing with O and early B stars there are serious stellar winds and wind-wind interaction to be considered. These could well smooth out the slight the infection point of a semidetacted light curve so as to mimic a contact light curve. It is suspect that this misleading configuration led to the wrong mass ratio and in turn resulted in very large masses. Therefore one should not trust the automatically arrived contact solution for these systems. Then one should limit the solution to semidetacted configure (mode 3 or 4 of the W-D method) for those systems. Therefore it is recommended that the observations of these systems should be re-analyzed. Since most of these system are single-line binaries one might be able to obtain more reasonable masses with reliable photometric mass ratios.

Leung, K. C.

2007-08-01

277

Equations of motion of elliptic restricted problem of three bodies with variable mass  

NASA Astrophysics Data System (ADS)

The differential equations of motion of the elliptic restricted problem of three bodies with decreasing mass are derived. The mass of the infinitesimal body varies with time. We have applied Jeans' law and the space-time transformation of Meshcherskii. In this problem the space-time transformation is applicable only in the special case whenn=1,k=0,q=1/2. We have applied Nechvile's transformation for the elliptic problem. We find that the equations of motion of our problem differ from that of constant mass only by a small perturbing force.

Das, R. K.; Shrivastava, A. K.; Ishwar, B.

1988-12-01

278

Equations of motion of the restricted problem of three bodies with variable mass  

NASA Astrophysics Data System (ADS)

The differential equations of motion of the restricted three-body problem with decreasing mass are deduced under the assumption that the satellite mass varies with respect to time. The Jeans law and the space-time transformation contrast are applied to the Meshcherskii (1975) transformation. It is noted that the space-time transformation is applicable only in the special case where n = 1, k = zero, and q = 1/2. The equations of motion for the present problem differ from the equations of motion of the restricted three-body problem with constant mass only in the existence of small perturbing forces.

Shrivastava, A. K.; Ishwar, B.

1983-07-01

279

Recent Research on the Automated Mass Measuring System  

NASA Astrophysics Data System (ADS)

The research development of robotic measurement system as well as the representative automatic system were introduced in the paper, and then discussed a sub-multiple calibration scheme adopted on a fully-automatic CCR10 system effectively. Automatic robot system can be able to perform the dissemination of the mass scale without any manual intervention as well as the fast speed calibration of weight samples against a reference weight. At the last, evaluation of the expanded uncertainty was given out.

Yao, Hong; Ren, Xiao-Ping; Wang, Jian; Zhong, Rui-Lin; Ding, Jing-An

280

The relationship between Body Mass Index and abnormal psychological and personality variables  

Microsoft Academic Search

The Body Mass Index (BMI) was created in order to classify individuals into body weight categories ranging from below normal\\u000a to very obese, depending on the individual’s weight and height. The Body Mass Index has been identified as a marker for psychological\\u000a issues such as self-control, self-esteem, depression, and anxiety. This study used a data matrix composed of a sample

Miranda J. Ours; William U. Weiss; Cary Rostow; Robert Davis

2006-01-01

281

Goddard Conference on Mass Storage Systems and Technologies, volume 2  

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

282

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

NASA Technical Reports Server (NTRS)

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.

Lekashman, John

1998-01-01

283

Goddard Conference on Mass Storage Systems and Technologies, Volume 1  

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

284

6-Year Periodicity and Variable Synchronicity in a Mass-Flowering Plant  

PubMed Central

Periodical organisms, such as bamboos and periodical cicadas, are very famous for their synchronous reproduction. In bamboos and other periodical plants, the synchronicity of mass-flowering and withering has been often reported indicating these species are monocarpic (semelparous) species. Therefore, synchronicity and periodicity are often suspected to be fairly tightly coupled traits in these periodical plants. We investigate the periodicity and synchronicity of Strobilanthes flexicaulis, and a closely related species S. tashiroi on Okinawa Island, Japan. The genus Strobilanthes is known for several periodical species. Based on 32-year observational data, we confirmed that S. flexicaulis is 6-year periodical mass-flowering monocarpic plant. All the flowering plants had died after flowering. In contrast, we found that S. tashiroi is a polycarpic perennial with no mass-flowering from three-year individual tracking. We also surveyed six local populations of S. flexicaulis and found variation in the synchronicity from four highly synchronized populations (>98% of plants flowering in the mass year) to two less synchronized one with 11–47% of plants flowering before and after the mass year. This result might imply that synchrony may be selected for when periodicity is established in monocarpic species. We found the selective advantages for mass-flowering in pollinator activities and predator satiation. The current results suggest that the periodical S. flexicaulis might have evolved periodicity from a non-periodical close relative. The current report should become a key finding for understanding the evolution of periodical plants.

Kakishima, Satoshi; Yoshimura, Jin; Murata, Hiroko; Murata, Jin

2011-01-01

285

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

ERIC Educational Resources Information Center

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)

Gochman, Nathan; And Others

1979-01-01

286

Design and Manufacturing of Extremely Low Mass Flight Systems  

NASA Technical Reports Server (NTRS)

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.

Johnson, Michael R.

2002-01-01

287

Assessing the precision on the determination of the Martian CO2 seasonal mass budget from time-variable gravity observations  

NASA Astrophysics Data System (ADS)

A relative large amount of the CO2 of the atmosphere of Mars is seasonally exchanged with the surface through the condensation/sublimation process at the polar caps. The associated mass redistribution at planetary scale generates a fine seasonal variation of the gravity field of Mars, allowing for the estimation of the mass budget of the CO2 seasonal cycle at the polar caps. However, to derive this mass budget, the knowledge of the extent and of the CO2 deposit density of the caps is needed in addition to the determination of the time variable gravity field. In this study, the time variable gravity solution is obtained from the Precise Orbit Determination (POD) of Mars Global Surveyor (MGS), Mars Odyssey (ODY), and Mars Reconnaissance Orbiter (MRO) spacecraft. All tracking data from the beginning of the nominal mission up to the most recent available extended phases for each spacecraft have been taken into account, thus covering about 5 Martian years. From this dataset, the seasonal variations of the lumped zonal harmonics of degree two and three have been obtained, using the GINS software developed by the CNES and further adapted by Royal Observatory of Belgium for planetary geodesy applications. The extent of the polar caps has been modeled on the basis of the MGS/TES dataset. In addition, the effect of compaction on the volume density of the polar CO2 deposits has been taken into account. Both the time variable gravity solution (i.e. lumped zonal harmonics) and the polar caps model have been compared with outputs of Global Circulation Model (GCM), and with the estimation derived from the HEND data onboard Mars Odyssey, in order to assess the precision on the current estimation of the polar cap CO2 mass budget.

Rosenblatt, P.; Marty, J.; Le Maistre, S.; Dehant, V. M.; Karatekin, O.

2009-12-01

288

Performance evaluation of mass storage systems for scientific databases  

SciTech Connect

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.

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

1994-09-01

289

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

NASA Astrophysics Data System (ADS)

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.

Tang, Yifan

290

Learning Latent Variable and Predictive Models of Dynamical Systems.  

National Technical Information Service (NTIS)

In this thesis we propose novel learning algorithms that address the issues of model selection, local minima and instability in learning latent variable models. We show that certain 'predictive' latent variable model learning methods bridge the gap betwee...

S. M. Siddiqi

2009-01-01

291

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

Microsoft Academic Search

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

Ram K. Ramamurthi

1994-01-01

292

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

NASA Astrophysics Data System (ADS)

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

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

2012-10-01

293

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

Microsoft Academic Search

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

M. J. Bañuelos; J. R. Obeso

2003-01-01

294

Electromagnetic variable degrees of freedom actuator systems and methods  

DOEpatents

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.

Montesanti, Richard C. (Pleasanton, CA); Trumper, David L. (Plaistow, NH); Kirtley, Jr., James L. (Brookline, MA)

2009-02-17

295

Orbits and masses in the young triple system TWA 5  

NASA Astrophysics Data System (ADS)

Aims: We aim to improve the orbital elements and determine the individual masses of the components in the triple system TWA 5. Methods: Five new relative astrometric positions in the H band were recorded with the adaptive optics system at the Very Large Telescope (VLT). We combine them with data from the literature and a measurement in the Ks band. We derive an improved fit for the orbit of TWA 5Aa-b around each other. Furthermore, we use the third component, TWA 5B, as an astrometric reference to determine the motion of Aa and Ab around their center of mass and compute their mass ratio. Results: We find an orbital period of 6.03 ± 0.01 years and a semi-major axis of 63.7 ± 0.2 mas (3.2 ± 0.1 AU). With the trigonometric distance of 50.1 ± 1.8 pc, this yields a system mass of 0.9 ± 0.1 M?, where the error is dominated by the error of the distance. The dynamical mass agrees with the system mass predicted by a number of theoretical models if we assume that TWA5 is at the young end of the age range of the TW Hydrae association. We find a mass ratio of MAb/MAa = 1.3-0.4+0.6 , where the less luminous component Ab is more massive. This result is likely to be a consequence of the large uncertainties due to the limited orbital coverage of the observations. Based on observations made with ESO Telescopes at the La Silla Paranal Observatory under programme ID 079.C-0103, 081.C-0393, 386.C-0205, 087.C-0209, 088.C-0046, 089.C-0167, and 090.C-0184.

Köhler, R.; Ratzka, T.; Petr-Gotzens, M. G.; Correia, S.

2013-10-01

296

The value of rock mass classification systems for weak rock masses: a case example from Huntly, New Zealand  

Microsoft Academic Search

Three published rock mass classification systems (RMR, SMR, RMS) were applied to weak Waikato Coal Measure mudrocks in order to assess their value as indicators of rock mass conditions and stable slope angles. The SMR classification gives the most sensitive measure of rock mass conditions for the slopes studied, but none of the systems adequately predicts observed slope angles. Regression

Vicki Moon; Geoff Russell; Meagan Stewart

2001-01-01

297

Training of fuzzy inference systems by combining variable structure systems technique and Levenberg-Marquardt algorithm  

Microsoft Academic Search

This paper presents a novel training algorithm for fuzzy inference systems. The algorithm combines the Levenberg-Marquardt algorithm with variable structure systems approach. The combination is performed by expressing the parameter update rule in continuous time and application of sliding control method to the gradient based training procedure. In this paper, a fuzzy inference mechanism that can be trained such that

M. Onder Efe; Okyay Kaynak; Bogdan M. Wilamowski

1999-01-01

298

Variability of NO sub x emissions from modern mass-fired resource recovery facilities  

Microsoft Academic Search

A major change in NOâ emissions has occurred, as modern mass-fired resource recovery facilities have become operational and are compared to the older facilities designed in the 1970s. The increase in NOâ emissions that is now typical of modern units is a direct result of the use of computerized automatic combustion control which was developed to virtually eliminate the emissions

J. L. Hahn; D. S. Sofaer

1988-01-01

299

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

SciTech Connect

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.

Osten, Rachel; Livio, Mario; Lubow, Steve; Pringle, J. E.; Soderblom, David; Valenti, Jeff [Space Telescope Science Institute, Baltimore, MD 21218 (United States)

2013-03-10

300

Spatial and temporal variability of surface mass balance near Talos Dome, East Antarctica  

Microsoft Academic Search

Predictions concerning Antarctica's contribution to sea level change have been hampered by poor knowledge of surface mass balance. Snow accumulation is the most direct climate indicator and has important implications for paleoclimatic reconstruction from ice cores. Snow accumulation measurements (stake, core, snow radar) taken along a 500-km transect crossing Talos Dome (East Antarctica) have been used to assess accumulation signals

Massimo Frezzotti; Stefano Urbini; Marco Proposito; Claudio Scarchilli; Stefano Gandolfi

2007-01-01

301

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

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

302

Ultrasensitive nanomechanical mass sensor using hybrid opto-electromechanical systems.  

PubMed

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

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

2014-06-01

303

Ion optics system incorporating radio frequency mass separation  

NASA Technical Reports Server (NTRS)

Results of an experimental study are presented. They show that an RF mass discriminator, based on a Bennett mass spectrometer concept, can be used to discriminate between two species of ions with about a 2-to-1 charge-to-mass ratio. Such a device would be useful for separating monatomic and diatomic oxygen ions in a system designed to simulate the environment that spacecraft encounter in low earth orbit. The influence of changing mass discriminator parameters - such as the spacing of its grids, the amplitude and frequency of RF voltage signals applied to it and the current density of ions incident upon it - on its species discrimination capabilities is discussed. Experimental results are also compared to the results of a simple theoretical model to gain insight into the processes occurring in the discriminator. These results are shown to be in good agreement.

Anderson, John R.; Carruth, M. R., Jr.

1990-01-01

304

Nucleosynthesis in thermonuclear supernovae with tracers: convergence and variable mass particles  

NASA Astrophysics Data System (ADS)

Nucleosynthetic yield predictions for multidimensional simulations of thermonuclear supernovae generally rely on the tracer particle method to obtain isotopic information of the ejected material for a given supernova simulation. We investigate how many tracer particles are required to determine converged integrated total nucleosynthetic yields. For this purpose, we conduct a resolution study in the number of tracer particles for different hydrodynamical explosion models at fixed spatial resolution. We perform hydrodynamic simulations on a co-expanding Eulerian grid in two dimensions assuming rotational symmetry for both pure deflagration and delayed detonation Type Ia supernova explosions. Within a given explosion model, we vary the number of tracer particles to determine the minimum needed for the method to give a robust prediction of the integrated yields of the most abundant nuclides. For the first time, we relax the usual assumption of constant tracer particle mass and introduce a radially varying distribution of tracer particle masses. We find that the nucleosynthetic yields of the most abundant species (mass fraction >10-5) are reasonably well predicted for a tracer number as small as 32 per axis and direction - more or less independent of the explosion model. We conclude that the number of tracer particles that were used in extant published works appear to have been sufficient as far as integrated yields are concerned for the most copiously produced nuclides. Additionally we find that a suitably chosen tracer mass distribution can improve convergence for nuclei produced in the outer layer of the supernova, where the constant tracer mass prescription suffers from poor spatial resolution.

Seitenzahl, I. R.; Röpke, F. K.; Fink, M.; Pakmor, R.

2010-10-01

305

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

NASA Astrophysics Data System (ADS)

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.

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

2011-09-01

306

Effect of operator variability on microleakage with different adhesive systems  

PubMed Central

Objective: The objective of this study was to evaluate the effect of operator variability on microleakage with different adhesive systems. Materials and Methods: A total of 180 standardized Class V cavities were prepared on facial and lingual of 90 extracted human premolar teeth and randomly assigned to five groups according to the adhesive systems used (n = 36): Prime and Bond NT (PB), Single Bond (SB), Futura Bond NR, Xeno III (XE) and Adper Prompt-L-Pop (LP). The adhesive groups were then further subdivided into three operator groups according to level of clinical experience (n = 12): An undergraduate student, a research assistant and a faculty member. All cavities were restored with same composite resin. The restored teeth were thermocycled (500 cycles, 5-55°C) then immersed in 0.5% basic fuchsin and measured for leakage under a stereomicroscope. Statistical analyses were performed with the Kruskal-Wallis and Mann-Whitney U tests. Results: Significant inter-operator variation was found in the enamel margins in the XE group with significantly higher microleakage when used by the undergraduate student (P < 0.05). Although no significant differences in microleakage were found between adhesive systems for the research assistant and faculty member (P > 0.05), significant differences were observed between PB and LP, PB and XE, SB and LP and SB and XE in the enamel margins for the undergraduate student (P < 0.05). Conclusion: Microleakage of adhesive systems is more dependent on interactions between the operator and adhesive material than on the choice of adhesive material.

Karaman, Emel; Yazici, A. Ruya; Aksoy, Burak; Karabulut, Erdem; Ozgunaltay, Gul; Dayangac, Berrin

2013-01-01

307

Improving flow response of a variable-rate aerial application system by interactive refinement  

Microsoft Academic Search

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 the system manufacturer, Houma Avionics, Houma, LA, USA. The variable-rate application system consists of Differential Global Positioning System

Steven J. Thomson; Yanbo Huang; James E. Hanks; Daniel E. Martin; Lowrey A. Smith

2010-01-01

308

Unravelling in vitro variables of major importance for the outcome of mass spectrometry-based serum proteomics.  

PubMed

The use of mass spectrometry (MS) for analysing low-molecular weight proteins and peptides from biological fluids has a great, yet not fully realized, potential for biomarker discovery. To prune MS-data as much as possible for non-relevant non-biological variation the development of standardized protocols for handling and processing the samples before MS and adjusting data after MS to compensate for method-induced variability are warranted. This calls for knowledge about how different variables contribute to MS-based proteome analyses. In addition, identification of the peptides involved in pre-analytical variation will be helpful in evaluating the clinical significance of predictive models derived from MS data. Using human sera, extraction by weak cation-exchange magnetic beads, and analysis by MALDI-TOF MS we here evaluated pre-analytical variation and identify peptides involved in this. The influences of humidity, temperature, and time for preparation of sera on spectral changes were evaluated. Also, the reproducibility of the methods and the effect of a baseline correction procedure were examined. Low temperatures, short handling times, and a baseline correction procedure minimize the contribution of artifacts to sample variability as observed by MS. The complement split product C3f and fragments thereof appear to be sensitive indicators of sample handling induced modifications. Other peptides that are indicative of such variability are fibrin and kininogen fragments. Using strict experimental guidelines as well as standardized sample collection procedures it is possible to obtain reproducible peak intensities and positions in serum mass profiling using magnetic bead-based fractionation and MALDI-TOF MS. PMID:17112795

West-Nørager, Mikkel; Kelstrup, Christian Dahl; Schou, Christian; Høgdall, Estrid V; Høgdall, Claus K; Heegaard, Niels H H

2007-02-15

309

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

NASA Astrophysics Data System (ADS)

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.

Velicogna, I.; Wahr, J.

2013-06-01

310

Greenland ice sheet surface mass-balance variability: 1991-2003  

Microsoft Academic Search

The Polar MM5 mesoscale atmospheric model was run for 13 years (1991-2003) over Greenland at 24 km horizontal resolution (Box and others, 2004). The model physics were driven by satellite, station and weather-balloon observational data assimilation, i.e. European Centre for Medium-Range Weather Forecasts (ECMWF) operational analysis. The analysis in this study focuses on the response of the surface mass balance

J. E. Box

2005-01-01

311

Dual Source Mass Spectrometer and Sample Handling System  

NASA Technical Reports Server (NTRS)

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.

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

312

Advanced Life Support Equivalent System Mass Guidelines Document  

NASA Technical Reports Server (NTRS)

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.

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

313

Estimation of convective mass transfer in solar distillation systems  

Microsoft Academic Search

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

Sanjay Kumar; G. N. Tiwari

1996-01-01

314

Satellite masses in the Uranus and Neptune systems  

Microsoft Academic Search

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

R. Greenberg

1984-01-01

315

Dynamical Effects of Mass Exchange in Close Binary Systems.  

National Technical Information Service (NTIS)

The problem of mass exchange in a close binary system is studied from the point of view of the evolution of the orbital elements. It is assumed that the original orbit is nearly circular and one of the components has expanded and fills the area inside the...

J. D. Hadjidemetriou

1968-01-01

316

A common mass scaling for satellite systems of gaseous planets.  

PubMed

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

Canup, Robin M; Ward, William R

2006-06-15

317

Correlated X-ray/ultraviolet/optical variability in the very low mass AGN NGC 4395  

NASA Astrophysics Data System (ADS)

We report the results of a 1-yr Swift X-ray/ultraviolet (UV)/optical programme monitoring the dwarf Seyfert nucleus in NGC 4395 in 2008-2009. The UV/optical flux from the nucleus was found to vary dramatically over the monitoring period, with a similar pattern of variation in each of the observed UV/optical bands (spanning 1900-5500 Å). In particular, the luminosity of NGC 4395 in the 1900 Å band changed by more than a factor of 8 over the monitoring period. The fractional variability was smaller in the UV/optical bands than that seen in the X-rays, with the X-ray/optical ratio increasing with increasing flux. Pseudo-instantaneous flux measurements in the X-ray and each UV/optical band were well correlated, with cross-correlation coefficients of ?0.7, significant at 99.9 per cent confidence. Archival Swift observations from 2006 sample the intra-day X-ray/optical variability on NGC 4395. These archival data show a very strong correlation between the X-ray and b bands, with a cross-correlation coefficient of 0.84 (significant at >99 per cent confidence). The peak in the cross-correlation function is marginally resolved and asymmetric, suggesting that X-rays lead the b band, but by ?1 h. In response to recent (2011 August) very high X-ray flux levels from NGC 4395 we triggered Swift target of opportunity observations, which sample the intra-hour X-ray/UV variability. These observations indicate, albeit with large uncertainties, a lag of the 1900 Å band behind the X-ray flux of ˜400 s. The tight correlation between the X-ray and UV/optical lightcurves, together with the constraints we place on the lag time-scale, is consistent with the UV/optical variability of NGC 4395 being primarily due to reprocessing of X-ray photons by the accretion disc.

Cameron, D. T.; McHardy, I.; Dwelly, T.; Breedt, E.; Uttley, P.; Lira, P.; Arevalo, P.

2012-05-01

318

Simultaneous thermal analysis — Mass spectrometer skimmer coupling system  

Microsoft Academic Search

A mass spectrometer coupling system for simultaneous TG\\/DSC\\/DTA-QMS measurements will be introduced that is capable of operation\\u000a at temperatures up to 2000°C. The coupling is maintained at a temperature very close to that of the sample, minimizing condensation,\\u000a and features an extremely short gas flow path. The efficiency of this coupling system will be demonstrated through examples\\u000a from the area

W.-D. Emmerich; E. Post

1997-01-01

319

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

NASA Astrophysics Data System (ADS)

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.

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

2008-06-01

320

Information-disturbance tradeoff in continuous-variable Gaussian systems  

SciTech Connect

We address the information-disturbance tradeoff for state measurements on continuous variable Gaussian systems and suggest minimal schemes for implementations. In our schemes, the symbols from a given alphabet are encoded in a set of Gaussian signals which are coupled to a probe excited in a known state. After the interaction the probe is measured, in order to infer the transmitted state, while the conditional state of the signal is left for the subsequent user. The schemes are minimal, i.e., involve a single additional probe, and allow for the nondemolitive transmission of a continuous real alphabet over a quantum channel. The tradeoff between information gain and state disturbance is quantified by fidelities and, after optimization with respect to the measurement, analyzed in terms of the energy carried by the signal and the probe. We found that transmission fidelity only depends on the energy of the signal and the probe, whereas estimation fidelity also depends on the alphabet size and the measurement gain. Increasing the probe energy does not necessarily lead to a better tradeoff, the most relevant parameter being the ratio between the alphabet size and the signal width, which in turn determine the allocation of the signal energy.

Genoni, Marco G.; Paris, Matteo G. A. [Dipartimento di Fisica dell'Universita di Milano, Milan (Italy)

2006-07-15

321

Variable speed, condensing steam turbine and power system  

Microsoft Academic Search

The variable speed condensing steam turbine is a simplified and effective steam expander which is built mainly of simple, lowcost sheet metal parts and is designed to provide a variable speed\\/torque output range. The turbine concept is based on the past tesla turbine principle of equally spaced rotor discs to provide a long helical path for steam expansion with high

1980-01-01

322

Dissecting Variability in Responses to Cancer Chemotherapy Through Systems Pharmacology  

Microsoft Academic Search

Variability in patient responses to even the most potent and targeted therapeutics is now the primary challenge facing drug discovery and patient care, particularly in oncology and immune therapy. Variability with respect to mechanisms of induced resistance is observed both in drug-naive patients and among those who are initially responsive. Genomics has developed powerful tools for systematic interrogation of disease

R Yang; M Niepel; T K Mitchison; P K Sorger

2010-01-01

323

Production variability in manufacturing systems: Bernoulli reliability case  

Microsoft Academic Search

The problem of production variability in serial manufacturing lines with unreliable machines is addressed. Bernoulli statistics of machine reliability are assumed. Three problems are considered: the problem of production variance, the problem of constant demand satisfaction, and the problem of random demand satisfaction generated by another (unreliable) production line. For all three problems, bounds on the respective variability measures are

Jingshan Li; Semyon M. Meerkov

2000-01-01

324

High-performance mass storage system for workstations  

NASA Technical Reports Server (NTRS)

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).

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

1993-01-01

325

Mass Loss and Narrow Absorption Component VAriability in Xiper and Delta Ori  

NASA Astrophysics Data System (ADS)

The goal of this investigation is a detailed study of the timescales, and nature, of variability in narrow absorption components and the underlying P Cygni profiles of two early type stars Xi Per (07.5 III or I) and Delta Ori (09.5 III). Shortward displaced relatively narrow absorption components are a common phenomenon in UV P Cygni profiles of many 0 Stars and B super giants, as well as some Be stars (Lamers et al. 1982; see for a review Henrichs 1984). Despite being virtually ubiquitous, and often a dominant characteristic of unsaturated P Cygni profiles, the origin of the narrow components is not known. Detailed analysis of these variable features is therefore clearly important to the understanding of the nature of stellar winds in early type stars. We propose to carry out intensive short timescale IUE observations of Xi Per and 6 Ori. An ongoing detailed survey of narrow components in early-type stars based on IUE databank and literature searches, suggests that these two stars present an exceptional opportunity to study rapid (hourly) changes in the strength and velocities of narrow absorption features in O stars. Furthermore these stars also exhibit extensive (though not necessarily correlated) changes in the underlying stellar wind P Cygni profiles. The new data are needed (1) to establish the timescale for formation of the high velocity narrow lines in the form of broad low velocity absorption. Recently obtained data might suggest a possible periodicity in formation time of these broad features in the order of a day (2) to derive a timescale for acceleration of the absorption from low to high velocity, which is of the order of half a day (3) to find out which of the presently existing different models is able to describe the observed behavior, and (4) to give more insight in this fundamental aspect of stellar wind structure of early-type stars.

Conti, Peter S.

326

Mass independent kinetic energy reducing inlet system for vacuum environment  

DOEpatents

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.

Reilly, Peter T.A.

2013-12-03

327

Mass independent kinetic energy reducing inlet system for vacuum environment  

DOEpatents

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.

Reilly, Peter T. A. [Knoxville, TN

2010-12-14

328

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

NASA Astrophysics Data System (ADS)

Simultaneous and continuous measurements of PM2.5 and PM10 along with other co-existent pollutants viz., black carbon (BC), CO, NO and NOx were carried out over Delhi with high resolution (5 min) datasets from 1st Sept. 2010 to 23rd Aug. 2012. Arithmetic mean mass concentrations of PM2.5 and PM10 were about 130 ± 103 and 222 ± 142 ?g m- 3 respectively during the entire measurement period, which are considerably higher than the annual averages of PM2.5 and PM10, stipulated by the National and International standards. It was noticed that the fine mode particles (PM2.5) were higher than the coarse mode particles (PM10-2.5) during post-monsoon (~ 89%), winter (~ 69%) and monsoon (~ 64%) periods; however, PM10-2.5 was higher (~ 22%) than PM2.5 during summer. Arithmetic mean mass concentrations of BC, CO, NO and NOx were about 7 ± 5 ?g m- 3, 2 ± 1 ppm, 17 ± 17 ppb and 30 ± 24 ppb, respectively. In the present study, highest fraction of BC (~ 6%) in PM2.5 mass was in winter, whereas the lowest fraction (~ 4%) was in summer. Relationships among PMs (particulate matters) and other pollutants indicated that the fine mode particles are highly correlated with BC (0.74) and CO (0.51). The effects of meteorological parameters on aerosols have been studied and a significant negative relationship (- 0.45) between mixing height (MH) and PM2.5 has been noticed. Higher correlation was during winter (- 0.55), however lower was in summer (- 0.16). Relation between visibility (VIS) and PM2.5 was higher during post-monsoon (- 0.85) and winter (- 0.78) when the visibility was around 2 km; however, it was relatively less correlated when VIS was greater than 2 km during summer and monsoon. Relationship between PM2.5 and relative humidity (RH) showed a significant negative correlation (- 0.56) for the entire study period. A positive correlation (0.32) was observed during the winter period with fine mode particles whereas negative correlation was seen with coarse mode particles during monsoon (- 0.70) and summer (- 0.51).

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

2014-08-01

329

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)

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.

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

330

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

Microsoft Academic Search

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

R. Karunakaran; S. Iniyan; Ranko Goic

2010-01-01

331

Preprocessing, variable selection, and classification rules in the application of SIMCA pattern recognition to mass spectral data  

SciTech Connect

In a recent report a strategy was proposed for the classification and identification of toxic organic compounds observed in ambient air from mass spectra using computational pattern recognition based on SIMCA principal components modeling of the autocorrelation transformed mass spectra. With this technique very good classification and identification results (87% and 84%, respectively) were obtained with GC/MS from training and calibration data for the 78 toxic compounds targeted for routine monitoring in ambient air. However, when applied to GC/MS ambient air field data, a number of hydrocarbons were incorrectly classified as chlorocarbons indicating that the training sets were not optimal for discriminating between these classes. A new strategy for data reprocessing, variable selection and class model optimization has been developed to solve this problem. Only the sixteen most intense ions in each mass spectrum are retained. The MS data are scaled by taking the square root of the intensities and the autocorrelation transform is then taken. A training class has been introduced for hydrocarbons in addition to three other classes. The original SIMCA classification rule has been modified to give a more reasonable approximation of the training set pattern structure and object distances from the class models.

Dunn, W.J.; Emery, S.L.; Graham Glen, W.; Scott, D.R.

1989-01-01

332

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

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

333

A system of three-dimensional complex variables  

NASA Technical Reports Server (NTRS)

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

Martin, E. Dale

1986-01-01

334

Construction of a kinematic variable sensitive to the mass of the Standard Model Higgs boson in H ? WW* ? ? + ??-? ¯ using symbolic regression  

NASA Astrophysics Data System (ADS)

We construct a kinematic variable that is sensitive to the mass of the Standard Model Higgs boson ( M H ) in the H ? WW ? ? ?+ ??- ?¯ channel using symbolic regression method. Explicit mass reconstruction is not possible in this channel due to the presence of two neutrinos that escape detection. Mass determination problem is that of finding a mass-sensitive function that depends on the measured observables. We use symbolic regression, which is a symbolic approach to the problem of non-linear regression, to derive an analytic formula sensitive to M H from the two lepton momenta and the missing transverse momentum. Using the newly-derived mass-sensitive variable, we expect Higgs mass resolutions between 1 to 4 GeV for M H between 130 and 190 GeV at the LHC with 10 fb -1 of data. This is the first time symbolic regression method has been applied to a particle physics problem.

Choi, Suyong

2011-08-01

335

Stability and bifurcation of nonconstant solutions to a reaction-diffusion system with conservation of mass  

NASA Astrophysics Data System (ADS)

We deal with a two-component system of reaction-diffusion equations with conservation of mass in a bounded domain with the Neumann or periodic boundary conditions. This system is proposed as a conceptual model for cell polarity. Since the system has conservation of mass, the steady state problem is reduced to that of a scalar reaction-diffusion equation with a nonlocal term. That is, there is a one-to-one correspondence between an equilibrium solution of the system with a fixed mass and a solution of the scalar equation. In particular, we consider the case when the reaction term is linear in one variable. Then the equations are transformed into the same equations as the phase-field model for solidification. We thereby show that the equations allow a Lyapunov function. Moreover, by investigating the linearized stability of a nonconstant equilibrium solution, we prove that given a nondegenerate stable equilibrium solution of the nonlocal scalar equation, the corresponding equilibrium solution of the system is stable. We also exhibit global bifurcation diagrams for equilibrium solutions to specific model equations by numerics together with a normal form near a bifurcation point.

Morita, Yoshihisa; Ogawa, Toshiyuki

2010-06-01

336

Mass-Independent Fractionation of Mercury in Hydrothermal Systems  

NASA Astrophysics Data System (ADS)

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 (?199Hg = 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.

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

2008-12-01

337

Scalability and Performance Improvements in the Fermilab Mass Storage System  

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

338

Prediction and Analysis of Variable Reluctance Stepmotor Drive Systems.  

National Technical Information Service (NTIS)

A relationship between the electric terminal parameters and output/input power is derived for conventional doubly-salient synchronous machines and extended to include the variable reluctance motor. The advantages and limitations of the drive-schemes are s...

D. W. J. Pulle

1982-01-01

339

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

NASA Technical Reports Server (NTRS)

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.

Chao, Benjamin F.

2004-01-01

340

Power Conditioner with Variable Switching Control for Thermoelectric Generator Systems  

NASA Astrophysics Data System (ADS)

A thermoelectric (TE) power conditioner maintaining high efficiency over a wide input power range has been developed. Variable switching frequency operation is shown to give an improvement in efficient operating range. The input range showing more than 90% conversion efficiency is expanded to more than 25% by introducing a low-power controller circuit and variable switching frequency control. The TE power conditioner showed excellent response against a change in thermoelectric generator (TEG) output and load, making it suitable for automotive applications.

Nagayoshi, Hiroshi; Maiwa, Hiroshi; Kajikawa, Takenobu

2013-07-01

341

Analysis and Synthesis of High Gain and Variable Structure Feedback Systems.  

National Technical Information Service (NTIS)

This study deals with the analysis and synthesis of two classes of multivariable feedback systems, high gain feedback systems and variable structure systems (VSS), subject to parameter variations and disturbances. First is examined the insensitivity prope...

K. K. D. Young

1977-01-01

342

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

343

The effect of including molecular opacities of variable composition on the evolution of intermediate-mass AGB stars  

NASA Astrophysics Data System (ADS)

Calculations from stellar evolutionary models of low- and intermediate-mass asymptotic giant branch (AGB) stars provide predictions of elemental abundances and yields for comparison to observations. However, there are many uncertainties that reduce the accuracy of these predictions. One such uncertainty involves the treatment of low-temperature molecular opacities that account for the surface abundance variations of C, N and O. A number of prior calculations of intermediate-mass AGB stellar models that incorporate both efficient third dredge-up and hot bottom burning include a molecular opacity treatment which does not consider the depletion of C and O due to hot bottom burning. Here we update the molecular opacity treatment and investigate the effect of this improvement on calculations of intermediate-mass AGB stellar models. We perform tests on two masses, 5 and 6 M?, and two metallicities, Z = 0.001 and 0.02, to quantify the variations between two opacity treatments. We find that several evolutionary properties (e.g. radius, Teff and Tbce) are dependent on the opacity treatment. Larger structural differences occur for the Z = 0.001 models compared to the Z = 0.02 models indicating that the opacity treatment has a more significant effect at lower metallicity. As a consequence of the structural changes, the predictions of isotopic yields are slightly affected with most isotopes experiencing changes up to 60 per cent for the Z = 0.001 models and 20 per cent for the Z = 0.02 models. Despite this moderate effect, we conclude that it is more fitting to use variable molecular opacities for models undergoing hot bottom burning.

Fishlock, C. K.; Karakas, A. I.; Stancliffe, R. J.

2014-02-01

344

Fourth NASA Goddard Conference on Mass Storage Systems and Technologies  

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

345

Possible role of the white dwarf in grain formation in cataclysmic variable systems  

NASA Astrophysics Data System (ADS)

The authors consider the possibility that carbon, in the form of the allotrope carbyne, might form in the atmosphere of the white dwarf in a cataclysmic variable system, and be expelled from the system by radiation pressure. It seems that, under some circumstances, cataclysmic variable systems may indeed have carbon dust in their vicinity.

Albinson, J. S.; Evans, A.

1987-03-01

346

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

NASA Astrophysics Data System (ADS)

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.

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

2012-09-01

347

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)

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.

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

2000-01-01

348

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

DOEpatents

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.

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

2013-10-22

349

Mass-Flow-Meter Leak-Testing System  

NASA Technical Reports Server (NTRS)

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.

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

1996-01-01

350

Decadal variability in coupled sea-ice-thermohaline circulation systems  

SciTech Connect

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.

Yang, J. [Woods Hole Oceanographic Institution, Woods Hole, MA (United States)] [Woods Hole Oceanographic Institution, Woods Hole, MA (United States); Neelin, J.D. [Univ. of California, Los Angeles, CA (United States)] [Univ. of California, Los Angeles, CA (United States)

1997-12-01

351

System Modeling of Lunar Oxygen Production: Mass and Power Requirements  

NASA Technical Reports Server (NTRS)

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.

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

2007-01-01

352

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

NASA Astrophysics Data System (ADS)

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

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

2010-04-01

353

An extrasolar planetary system with three Neptune-mass planets.  

PubMed

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

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

354

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)

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.

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

2002-01-01

355

Integration of an Energy Capacitor System With a Variable-Speed Wind Generator  

Microsoft Academic Search

This paper presents a system using an energy capacitor system (ECS) to smoothen the output power fluctuation of a variable-speed wind farm. The variable-speed wind turbine driving a permanent-magnet synchronous generator is considered to be connected to the ac network through a fully controlled frequency converter. The detailed modeling and control strategy of the frequency converter as well as variable-speed

S. M. Muyeen; Rion Takahashi; Toshiaki Murata; Junji Tamura

2009-01-01

356

Design of a ram accelerator mass launch system  

NASA Technical Reports Server (NTRS)

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.

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

1988-01-01

357

Tests of thermodynamic theory of relative stability in one-variable systems  

Microsoft Academic Search

Schloegl's criterion for equistability of two stable stationary states of an inhomogeneous chemical kinetic system is valid only for single-variable cases dependent along a single spatial coordinate. We test the thermodynamic theory, developed in the preceding article for multivariable systems, in one dimension by comparison with calculations based on the deterministic reaction-diffusion equation for a cubic Schloegl model (single variable).

A. N. Wolff; A. Hjelmfelt; J. Ross; P. M. Hunt

1993-01-01

358

Energy efficient fixed-priority scheduling for real-time systems on variable voltage processors  

Microsoft Academic Search

Energy consumption has become an increasingly important consideration in designing many real-time embedded systems. Variable voltage processors, if used properly, can dramatically reduce such system energy consumption. In this paper, we present a technique to determine voltage settings for a variable voltage processor that utilizes a fixed priority assignment to schedule jobs. Our approach also produces the minimum constant voltage

Gang Quan; Xiaobo Hu

2001-01-01

359

Development of a Solar LED Illumination Control System Based on Variable Universe Adaptive Fuzzy PID Controller  

Microsoft Academic Search

Aimed at the shortcomings that traditional fuzzy logic control method for solar LED illumination system maximum power point tracking (MPPT) control system, a novel solar LED illumination control strategy based on variable univers adaptive fuzzy PID controller is proposed.The controller can automatically adjusts the variable univers with the change of photovoltaic output power deviation, to realize the solar LED illumination

Yiwang Wang; Shuo Wu

2011-01-01

360

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

Microsoft Academic Search

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

Chongsheng Hou

2011-01-01

361

Multi-scale characterization of soil variability within an agricultural landscape mosaic system in southern Cameroon  

Microsoft Academic Search

The characterization of soil spatio-temporal variability is essential to achieve a better understanding of complex relations between soil properties, environmental factors and land use systems. This study evaluates the sources of soil variability in an agricultural landscape mosaic system in the humid forest of southern Cameroon at four scales: (i) the regional level as affected by soil-forming factors; (ii) the

Martin Yemefack; David G. Rossiter; Rosaline Njomgang

2005-01-01

362

Mock-Up and Testing of a Variable Volume Laboratory Fume Hood Exhaust System.  

National Technical Information Service (NTIS)

A test of an ANL-designed variable volume system prototype used to displace an existing constant volume fume hood ventilation system in a laboratory of the Materials Science Division is described. Performance characteristics such as response, stability, r...

J. Vresk P. R. Hirsch S. A. Davis G. E. Myers J. L. Woodring

1980-01-01

363

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

NASA Technical Reports Server (NTRS)

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.

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

1985-01-01

364

Optimal Allocation of Work in Production Line Systems with Variable Operation Times.  

National Technical Information Service (NTIS)

The report investigates the design of multi-station queueing systems such as those arising in production or assembly lines. The main problem considered is to identify the optimal allocation of work in production line systems with variable operation times ...

F. S. Hillier R. W. Boling

1971-01-01

365

Research and design of high speed mass image storage system  

NASA Astrophysics Data System (ADS)

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.

Li, Yu-Feng; Xue, Rong-Kun; Liang, Fei

2009-07-01

366

Hybrid excitation timing system of Electromagnetic Continuously Variable Transmission  

Microsoft Academic Search

Air-gap magnetic field of electromagnetic continuously variable transmission (EMCVT) is composed by permanent magnet and electromagnetic excitation winding. FEM is adopted to study the three-dimensional airgap magnetic field based on mathematical model. The trust deduced of air-gap magnetic field from FEM is verifield been adjusted by the theoretic prototype. The study shows the magnetic field of EMCVT is high and

Fu xingfeng; Luo yutao

2008-01-01

367

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

DOEpatents

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.

Frank, A.A.

1984-07-10

368

Body mass, fat percentage, and fat free mass as reference variables for lung function: effects on terms for age and sex  

Microsoft Academic Search

BACKGROUNDSex specific cross sectional reference values for lung function indices usually employ a linear model with terms for age and stature. The effects of also matching for body mass index (BMI = mass\\/stature2) or its components, fat percentage of body mass (fat%) and fat free mass index (FFMI = fat free mass\\/stature2) were studied.METHODSThe subjects were 458 asymptomatic male and

J E Cotes; D J Chinn; J W Reed

2001-01-01

369

Ultrastable superconducting magnet system for a penning trap mass spectrometer  

NASA Astrophysics Data System (ADS)

A custom-designed magnet/cryostat system is described which has demonstrated remarkably improved field stability over previous designs. To shield from external magnetic noise, a custom-fabricated flux-gate device remotely senses the changes in magnetic field and cancels them out at the site of the magnet/cryostat via a 1.7-m-diam Helmholtz coil. To provide further shielding, the basic superconducting solenoid includes a passive flux-stabilizing coil. To stabilize internal field shifts, the temperature of the materials in the immediate vicinity of the solenoid (which have a temperature-dependent susceptibility) is stabilized via the new cryostat geometry and by controlling the pressure of the evaporating liquid helium to a few parts per million. As a result, the total system now has a composite shielding factor of approximately 104 and an overall temporal stability on the order of 17(2) parts in 1012 per hour. This instrument, the heart of our new Penning trap mass spectrometer, has recently been used to determine a preliminary value of the proton's atomic mass to an accuracy of 1.4 parts in 1010. With the new magnet/cryostat system, this spectrometer now has a potential resolution which exceeds 2 parts in 1011 with 100 hours of data using a single carbon 4+ ion.

van Dyck, R. S.; Farnham, D. L.; Zafonte, S. L.; Schwinberg, P. B.

1999-03-01

370

Grand challenges in mass storage: A systems integrators perspective  

NASA Technical Reports Server (NTRS)

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.

Lee, Richard R.; Mintz, Daniel G.

1993-01-01

371

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)

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.

Choi, Jae Young; Ro, Yong Man

2012-11-01

372

The Masses of Two Binary Neutron Star Systems  

Microsoft Academic Search

The measurement or constraint of the masses of neutron stars and their binary\\u000acompanions tests theories of neutron star structure and of pulsar formation and\\u000aevolution. We have measured the rate of the general relativistic advance of the\\u000alongitude of periastron for the pulsar PSR B1802$-$07:\\u000a$\\\\dot\\\\omega=0\\\\fdg060\\\\pm0\\\\fdg009\\\\,\\\\mbox{yr}^{-1}$, which implies a total system\\u000amass, pulsar plus companion star, of $M=1.7\\\\pm0.4\\\\,\\\\Msun$. We

S. E. Thorsett; Z. Arzoumanian; M. M. McKinnon; J. H. Taylor

1993-01-01

373

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

SciTech Connect

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.

Koenigsberger, Gloria [Instituto de Ciencias FIsicas, Universidad Nacional Autonoma de Mexico, Av. Universidad s/n, Cuernavaca, Mor. 62210 (Mexico); Georgiev, Leonid [Instituto de AstronomIa, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-264, Mexico D.F. 04510 (Mexico); Hillier, D. John [Department of Astronomy, 3941 O'Hara Street, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Morrell, Nidia [Las Campanas Observatory, The Carnegie Observatories, Colina El Pino s/n, Casillas 601, La Serena (Chile); Barba, Rodolfo [Departamento de Fisica, Universidad de la Serena, Benavente 980, La Serena (Chile); Gamen, Roberto, E-mail: gloria@astro.unam.m, E-mail: georgiev@astro.unam.m, E-mail: djh@rosella.phyast.pitt.ed, E-mail: nmorrell@lco.c, E-mail: rbarba@dfuls.c, E-mail: rgamen@gmail.co [Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, and Instituto de Astrofisica de La Plata (CCT La Plata-CONICET), Paseo del Bosque S/N, B1900FWA, La Plata (Argentina)

2010-06-15

374

Propagation of impact-induced longitudinal waves in mechanical systems with variable kinematic structure  

Microsoft Academic Search

In the present investigation of the propagation of impact-induced longitudinal waves in mechanical systems with variable kinematic structure, the mechanical system's configuration is identified by means of two different sets of modes: the first describing the system configuration before change in system topology, and the second describing the configuration of the system after topology changes. It is assumed that collision

A. A. Shabana; W. H. Gau

1993-01-01

375

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

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

376

Prediction and analysis of variable reluctance stepmotor drive systems  

NASA Astrophysics Data System (ADS)

A relationship between the electric terminal parameters and output/input power is derived for conventional doubly-salient synchronous machines and extended to include the variable reluctance motor. The advantages and limitations of the drive-schemes are shown in Blondel diagrams and torque speed curves. A general method for obtaining a quantitative assessment of drive-schemes is developed by the introduction of so-called performance figures, related to the output power and efficiency. From this method applied to four drive schemes, it is concluded that severe performance degradation is the result of using a forging resistance in a drive-scheme. A forced decay unipolar chopper drive is presented.

Pulle, D. W. J.

1982-01-01

377

Power optimization of variable-voltage core-based systems  

Microsoft Academic Search

The growing class of portable systems, such as personal computing and communication devices, has resulted in a new set of system design requirements, mainly characterized by dominant importance of power minimization and design reuse. The energy efficiency of systems-on-a-chip (SOC) could be much improved if one were to vary the supply voltage dynamically at run time. We develop the design

Inki Hong; Darko Kirovski; Gang Qu; Miodrag Potkonjak; Mani B. Srivastava

1999-01-01

378

Seasonal variability of water mass distribution in the southeastern Beaufort Sea determined by total alkalinity and ?18O  

NASA Astrophysics Data System (ADS)

We examined the seasonal variability of water mass distributions in the southeastern Beaufort Sea from data collected between September 2003 and August 2004. Salinity, total alkalinity (TA) and isotopic composition (?18O) of seawater were used together as tracers of freshwater input, i.e., meteoric water and sea ice meltwater. We used an optimum multiparameter analysis to identify the different water masses, including the Mackenzie River, sea ice melt (SIM), winter polar mixed layer (PML), upper halocline water (UHW) with core salinity of 33.1 psu (Pacific origin) and Atlantic Water. Computed values of CO2 fugacity in seawater (fCO2-sw) show that the surface mixed layer (SML) remains mostly undersaturated (328 ± 55?atm, n = 552) with respect to the average atmospheric CO2 concentration (380 ± 5 ?atm) over the study period. The influence of the Mackenzie River (fCO2-SW > 500 ?atm) was relatively small in the southeastern Beaufort Sea, and significant fractions were only observed on the inner Mackenzie Shelf. The contribution of sea ice melt (fCO2-SW < 300 ?atm) to the SML could reach 30% beyond the shelf break and close to the ice pack in autumn. The density of the PML increased through the winter due to cooling and brine rejection. The winter PML reached a maximum depth of 70 m in late April. The UHW (fCO2-SW > 600 ?atm) was usually located between 120 and 180 m depth, but could contribute to the SML during wind-driven upwelling events, in summer and autumn, and during brine-driven eddies, in winter.

Lansard, Bruno; Mucci, Alfonso; Miller, Lisa A.; MacDonald, Robie W.; Gratton, Yves

2012-03-01

379

Design of adaptive variable structure controllers for perturbed time-varying state delay systems  

Microsoft Academic Search

The problem of stabilizing a class of perturbed linear dynamic systems with time-varying state delay is investigated in this paper. By applying the Lyapunov stability theorem, we develop a delay-independent adaptive variable structure controller to drive the states of system to zero. Based on the variable structure control (VSC) technique, the proposed controller can drive the system into a pre-specified

Chien-Hsin Chou; Chih-Chiang Cheng

2001-01-01

380

[Design of hand-held heart rate variability acquisition and analysis system].  

PubMed

A design of handheld heart rate variability acquisition and analysis system is proposed. The system collects and stores the patient's ECG every five minutes through both hands touching on the electrodes, and then -uploads data to a PC through USB port. The system uses software written in LabVIEW to analyze heart rate variability parameters, The parameters calculated function is programmed and generated to components in Matlab. PMID:23189641

Li, Kaiyuan; Wang, Buqing; Wang, Weidong

2012-07-01

381

Development and characterization of a variable turbulence generation system  

Microsoft Academic Search

Experimental turbulent combustion studies require systems that can simulate the turbulence intensities [u?\\/U\\u000a 0 ~ 20–30% (Koutmos and McGuirk in Exp Fluids 7(5):344–354, 1989)] and operating conditions of real systems. Furthermore, it is important to have systems where turbulence intensity can be\\u000a varied independently of mean flow velocity, as quantities such as turbulent flame speed and turbulent flame brush thickness\\u000a exhibit complex

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

2011-01-01

382

Spatial and temporal chemical variability in the Hillsborough River system  

Microsoft Academic Search

The Hillsborough River originates in the Green Swamp, a principal recharge area of the Floridan Aquifer system. As the river flows to Tampa Bay, its chemistry is influenced by a variety of natural and anthropogenic inputs. Spatial and temporal variations in the river's major ion concentrations, CO2-system chemistry, and nutrients were examined in a two-year study between 1999 and 2001.

Lori A. Pillsbury; Robert H. Byrne

2007-01-01

383

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

Microsoft Academic Search

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

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

1997-01-01

384

Volcanic Gas Emissions Mapping Using a Mass Spectrometer System  

NASA Technical Reports Server (NTRS)

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.

Griffin, Timothy P.; Diaz, J. Andres

2008-01-01

385

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

Microsoft Academic Search

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

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

1999-01-01

386

An integrated system for on-line intelligent monitoring and identifying process variability and its application  

Microsoft Academic Search

To reduce process variability in complex manufacturing processes, a tremendous need exists to integrate monitoring process variability (PV) and identification of source of out-of-control signals (SOS). The advent of advanced measurement and information technology has provided promising opportunities to improve product quality. In this paper, one integrated system is explored for intelligent monitoring PV and identifying of SOS in multivariate

S. Du; J. Lv; L. Xi

2010-01-01

387

Robust adaptive control for robotic manipulator based on chattering free variable structure system  

Microsoft Academic Search

In robotic manipulators there are many uncertainties such as dynamic parameters (eg., inertia and payload conditions), dynamical effects (e.g., complex nonlinear frictions), and unmodeled dynamics. Traditional linear controllers have many difficulties in treating these uncertainties. To overcome this problem, a robust adaptive control for robotic manipulator based on chattering free variable structure system is proposed. Conventional variable structure control (VSC)

Dimitri Mahayana; Sabat Anwari

2009-01-01

388

Note on the Functional Estimation of Values of Hidden Variables --- An Extended Module for Expert Systems.  

National Technical Information Service (NTIS)

The paper describes an extension of the author's work on the Generalized Production Rules System. In its original form, it could estimate at a given point of time or space the value of hidden variables -- variables that can be measured only intermittently...

N. V. Findler R. Lo

1982-01-01

389

Zero and root loci of disturbed spring-mass systems  

PubMed Central

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.

Lecomte, Christophe

2014-01-01

390

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

USGS Publications Warehouse

A field experiment at Owens (dry) Lake, California, tested whether and how the relative profiles of airborne horizontal mass fluxes for >50-??m wind-eroded particles changed with friction velocity. The horizontal mass flux at almost all measured heights increased proportionally to the cube of friction velocity above an apparent threshold friction velocity for all sediment tested and increased with height except at one coarsesand 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 downwind sampling site confirm that suspended particles are very important for mass budgets in large source areas and that saltation mass flux can be a variable fraction of total horizontal mass flux for soils with a substantial fraction of <100-??m particles.

Gillette, D. A.; Fryrear, D. W.; Xiao, J. B.; Stockton, P.; Ono, D.; Helm, P. J.; Gill, T. E.; Ley, T.

1997-01-01

391

Time-Variable Phenomena in the Jovian System.  

National Technical Information Service (NTIS)

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 ...

M. J. S. Belton R. A. West J. Rahe M. Pereyda

1989-01-01

392

[Thalassotherapy effect on cardiovascular system and cardiac rhythm variability].  

PubMed

A complex study of physiological parameters allowed us to analyse reactions of cardiovascular system to dipping into a hot water varying in salt concentrations. These reactions differ from those to dipping into cold water. Dipping into hot water leads to depression of the tonicity of parasympathic nervous system in such a manner that increased heart rate does not cause vascular contraction. Effects of water salt concentrations on the above parameters need further investigations. PMID:15759468

Merati, J; Solimene, U; Cherina, A; Piccini, J; Vaistainas, A

2005-01-01

393

Transient Finite Element Computations on a Variable Transputer System  

NASA Technical Reports Server (NTRS)

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

Smolinski, Patrick J.; Lapczyk, Ireneusz

1993-01-01

394

Mass discrimination monitoring and intercalibration of dual collectors in noble gas mass spectrometer systems  

Microsoft Academic Search

Accurate high-precision 40Ar\\/39Ar ages are limited, in part, by the degree of accuracy and precision of the measurement of the 36Ar atmospheric Ar contamination correction and the mass spectrometer mass fractionation bias (mass discrimination) correction. To improve the measurements of the low-level 36Ar signals, we have implemented digital ion-counting and multicollector data acquisition methods. The switch to the digital ion

Brent D. Turrin; Carl C. Swisher; Alan L. Deino

2010-01-01

395

Thermophoresis and chemical reaction effects on non-Darcy MHD mixed convective heat and mass transfer past a porous wedge in the presence of variable stream condition  

Microsoft Academic Search

An analysis is presented to investigate the effect of thermophoresis particle deposition and variable viscosity on non-Darcy MHD mixed convective heat and mass transfer of a viscous, incompressible and electrically conducting fluid past a porous wedge in the presence of chemical reaction. The wall of the wedge is embedded in a uniform non-Darcian porous medium in order to allow for

Ismoen Muhaimin; Ramasamy Kandasamy; I. Hashim

2009-01-01

396

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...

397

Vibrating Systems with Singular Mass-Inertia Matrices  

NASA Technical Reports Server (NTRS)

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.

Balakrishnan, A. V.

1996-01-01

398

Angular momentum and disk evolution in very low mass systems  

NASA Astrophysics Data System (ADS)

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.

Scholz, A.

399

The application of rock mass classification systems to underground excavation in weak limestone, Atatürk dam, Turkey  

Microsoft Academic Search

The Atatürk dam was built across the Firat River on clayey limestone. A grout curtain, providing impermeability in the left and right abutments, was done in grouting galleries. The well known rock mass classification systems for tunneling purposes [rock structure rating (RSR), rock mass rating (RMR) and rock mass quality index (Q)] were used to classify the rock mass along

A Tu?rul

1998-01-01

400

Mass Storage System Upgrades at the NASA Center for Computational Sciences  

Microsoft Academic Search

The NASA Center for Computational Sciences (NCCS) provides supercomputing and mass storage services to over 1200 Earth and space scientists. During the past two years, the mass storage system at the NCCS went through a great deal of changes both major and minor. Tape drives, silo control software, and the mass storage software itself were upgraded, and the mass storage

Adina Tarshish; Ellen Salmon; Medora Macie; Marty Saletta

2000-01-01

401

Models for Anisotropic Spherical Stellar Systems with a Central Point Mass and Keplerian Falloff Velocity Dispersions  

NASA Astrophysics Data System (ADS)

We add to the lore of spherical stellar system models a two-parameter family with an anisotropic velocity dispersion and a central point mass ("black hole"). The ratio of tangential to radial dispersions is constant, and constitutes the first parameter, while each dispersion decreases with radius as r-1/2. The second parameter is the ratio of the central point mass to the total mass. The Jeans equation is solved to give the density law in closed form: rho ~ (r/r0)- gamma /[1 + (r/r0)3- gamma ]2, where r0 is an arbitrary scale factor. The two parameters enter the density law only through their combination gamma . At the suggestion of Tremaine, we also explore models with only the root-sum-square of the velocities having a Keplerian run, but with a variable anisotropy ratio. This gives rise to a more versatile class of models, with analytic expressions for the density law and the dispersion runs, which contain more than one radius-scale parameter.

Milgrom, Mordehai

1997-02-01

402

MASSIS: a mass spectrum simulation system. 2: Procedures and performance.  

PubMed

The use of the mass spectral simulation system, MASSIS, is reported and its performance has been evaluated. The search for substructures matching with fragments stored in four pivot databases was realised using the Ullmann algorithm. Special cleavage rules, such as the McLafferty rearrangement, the retro-Diels-Alder reaction, elimination of a neutral small molecule and oxygen migration, are processed through shortest path and depth-first search algorithms. For a search in the database of small fragments, the key step is to determine the tautomeric fragments; then a match can be obtained using a subgraph isomorphism algorithm. A string match is used to determine peak intensity. If the limited environment of an atom is the same as that found in the database of relationships between fragment and intensity, this intensity value is assigned to the query atom. Performance in a set of tests is very important in evaluating the system performance. A comparison of peaks with an intensity greater than 5% (relative) shows that our system has a very high performance figure (> 90% ) for routine organic compounds. PMID:14624014

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

2003-01-01

403

Detection system for the St. George recoil mass separator  

NASA Astrophysics Data System (ADS)

The St. George recoil mass separator is designed for the study of low energy (?,?) reactions of astrophysical interest in inverse kinematics. The energy range of recoils will be 0.07 to 0.9 MeV/nucleon. A detection system is being developed for separating the recoils from the residual scattered beam at the focal plane. The detection system will consist of two position sensitive microchannel plate (MCPs) timing detectors separated by 50cm followed by a single sided silicon strip detector. Simulations were performed using the codes SIMION and GEANT4. Different designs for guiding the secondary electrons emitted from a thin carbon foil to the MCP were studied in the simulations. Good timing and position resolution and minimization of transmission loss due to grids were key factors in selecting the final design. Time of flight will be recorded between the two MCPs. The delay line technique will be used for extracting the position information from the MCPs. The energy of the recoils will be recorded by the Si detector. A dedicated vacuum chamber and the modular design of the detection system will facilitate future improvements and customization for particular experiments.

Kalkal, S.; Hinnefeld, J.; Morales, L.; Robertson, D.; Stech, E.; Berg, G. P. A.; Gorres, J.; Couder, M.; Wiescher, M.

2012-10-01

404

Physics design of fissile mass-flow monitoring system  

SciTech Connect

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.

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

1997-09-01

405

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

PubMed

The similarity search in theoretical mass spectra generated from protein sequence databases is a widely accepted approach for identification of peptides from query mass spectra produced by shotgun proteomics. Growing protein sequence databases and noisy query spectra demand database indexing techniques and better similarity measures for the comparison of theoretical spectra against query spectra. We employ a modification of previously proposed parameterized Hausdorff distance for comparisons of mass spectra. The new distance outperforms the original distance, the angle distance and state-of-the-art peptide identification tools OMSSA and X!Tandem in the number of identified peptides even though the q-value is only 0.001. When a precursor mass filter is used as a database indexing technique, our method outperforms OMSSA in the speed of search. When variable modifications are not searched, the search time is similar to X!Tandem. We show that the precursor mass filter is an efficient database indexing technique for high-accuracy data even though many variable modifications are being searched. We demonstrate that the number of identified peptides is bigger when variable modifications are searched separately by more search runs of a peptide identification engine. Otherwise, the false discovery rates are affected by mixing unmodified and modified spectra together resulting in a lower number of identified peptides. Our method is implemented in the freely available application SimTandem which can be used in the framework TOPP based on OpenMS. PMID:24231142

Novák, Ji?í; Sachsenberg, Timo; Hoksza, David; Skopal, Tomáš; Kohlbacher, Oliver

2013-01-01

406

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

NASA Technical Reports Server (NTRS)

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.

Bailey, G. A.

1980-01-01

407

Evaluation of the Effectiveness of a Variable Advisory Speed System on Queue Mitigation in Work Zones.  

National Technical Information Service (NTIS)

Variable Advisory Speed Systems (VASS) provide drivers with advanced warning regarding traffic speeds downstream to help them make better decisions. Vehicle use on highways is increasing and the need to improve highways brings increased construction of hi...

A. B. Wilson M. Saito

2011-01-01

408

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

DOEpatents

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.

Kumar, Aditya; Shi, Ruijie; Dokucu, Mustafa

2013-09-17

409

Time Evolution of the Dynamical Variables of a Stochastic System.  

ERIC Educational Resources Information Center

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)

de la Pena, L.

1980-01-01

410

Mass Deacidification Systems: Planning and Managerial Decision Making.  

ERIC Educational Resources Information Center

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

Turko, Karen

411

The Future of General Education in Mass Higher Education Systems.  

ERIC Educational Resources Information Center

Discusses the synergies and possible contradictions between general education and mass higher education. Explores whether they are complementary ideas because mass higher education must inevitably be general, or opposed ideas because general education espouses generic, holistic approaches to learning while mass education endorses eclectic, even…

Scott, Peter

2002-01-01

412

Tests of thermodynamic theory of relative stability in one-variable systems  

Microsoft Academic Search

Schlo¨gl’s criterion for equistability of two stable stationary states of an inhomogeneous chemical kinetic system is valid only for single-variable cases dependent along a single spatial coordinate. We test the thermodynamic theory, developed in the preceding article for multivariable systems, in one dimension by comparison with calculations based on the deterministic reaction-diffusion equation for a cubic Schlo¨gl model (single variable).

A. N. Wolff; A. Hjelmfelt; J. Ross; P. M. Hunt

1993-01-01

413

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

SciTech Connect

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.

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

2012-07-01

414

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

PubMed Central

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

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

2011-01-01

415

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

NASA Technical Reports Server (NTRS)

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.

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

2011-01-01

416

Variable Conduction System Disorders in Takotsubo Cardiomyopathy: A Case Series  

PubMed Central

Takotsubo cardiomyopathy is an acute cardiac condition characterized by transient systolic dysfunction of the left ventricular apex and mid-ventricle. Documented EKG presentations for Takotsubo cardiomyopathy include ST-segment elevation or T-wave inversion. These EKG presentations are included in the diagnostic requirements for Takotsubo cardiomyopathy. This paper presents two cases of atypical EKG presentations, both conduction system disorders, and their possible mechanisms. Changes to the diagnostic criteria for Takotsubo cardiomyopathy should be considered to include these variant EKG presentations.

Hoo, Aaron C; Azuma, Steven S

2014-01-01

417

Self-Calibrating, Variable-Flow Pumping System  

NASA Technical Reports Server (NTRS)

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.

Walls, Joe T.

1994-01-01

418

Peripheral variability and central constancy in mammalian visual system evolution  

PubMed Central

Neural systems are necessarily the adaptive products of natural selection, but a neural system, dedicated to any particular function in a complex brain, may be composed of components that covary with functionally unrelated systems, owing to constraints beyond immediate functional requirements. Some studies support a modular or mosaic organization of the brain, whereas others emphasize coordination and covariation. To contrast these views, we have analysed the retina, striate cortex (V1) and extrastriate cortex (V2, V3, MT, etc.) in 30 mammals, examining the area of the neocortex and individual neocortical areas and the relative numbers of rods and cones. Controlling for brain size and species relatedness, the sizes of visual cortical areas (striate, extrastriate) within the brains of nocturnal and diurnal mammals are not statistically different from one another. The relative sizes of all cortical areas, visual, somatosensory and auditory, are best predicted by the total size of the neocortex. In the sensory periphery, the retina is clearly specialized for niche. New data on rod and cone numbers in various New World primates confirm that rod and cone complements of the retina vary substantially between nocturnal and diurnal species. Although peripheral specializations or receptor surfaces may be highly susceptible to niche-specific selection pressures, the areal divisions of the cerebral cortex are considerably more conservative.

Kaskan, Peter M.; Franco, Edna Cristina S.; Yamada, Elizabeth S.; de Lima Silveira, Luiz Carlos; Darlington, Richard B.; Finlay, Barbara L.

2005-01-01

419

Dynamic response of variable frequency drives in electrical submersible pump systems  

Microsoft Academic Search

Dynamic response of variable frequency drives (VFD) during short-circuit faults for the electrical submersible pump (ESP) systems are investigated in this paper. Because of special characteristics of VFDs and ESP systems, the dynamic response of the drive during faults is quite different from that of general power distribution systems. The simulation conducted by PSCAD provides detailed and clear pictures how

Xiaodong Liang; Obinna Ilochonwu; Rotimi Adedun

2012-01-01

420

Subjective Effects of Variable Delay and Speech Clipping in Dynamically Managed Voice Systems  

Microsoft Academic Search

The purpose of this paper is to examine speech impairments likely to arise in dynamically managed voice (DMV) systems. DMV systems utilize speech activity detection to exploit speech idle time and variable bit rate coding to exploit nonstationary speech statistics. The emphasis here is on systems using speech detection. This processing introduces two impairments not commonly found in traditional communication

JOHN G. GRUBER; LEO STRAWCZYNSKI

1985-01-01

421

Finite element and reliability: a method for compound variables—application on a cracked heating system  

Microsoft Academic Search

Nuclear engineering systems are designed to ensure safety criteria. To predict the behavior of mechanical systems, the finite element analysis (FEA) is actually the main tool for numerical analysis of mechanical problems. In order to design a system under data variability considerations, performance functions have to be defined by the relationship between the action effects and the material strengths. Then

Alaa Mohamed; Maurice Lemaire; Jean-Claude Mitteau; Eric Meister

1998-01-01

422

Variable frequency controlled incremental conductance derived MPPT photovoltaic stand-along DC bus system  

Microsoft Academic Search

An incremental conductance (IC) derived MPPT PV stand-along dc bus system by constant-duty variable frequency control is proposed. Fast matching process to executing MPPT PV system is achieved by a simple control programming. The proposed PV system can provide enough energy to load as well as the battery charging with the residual energy. The feasibility is demonstrated by an example

Guan-Chyun Hsieh; Hung-Liang Chen; Yaohwa Chen; Chee-Ming Tsai; Shian-Shing Shyu

2008-01-01

423

Using Attributed Variables in the Implementation of Concurrent and Parallel Logic Programming Systems  

Microsoft Academic Search

Incorporating the possibility of attaching attributes to variables in a logic program- ming system has been shown to allow the addition of general constraint solving capabilities to it. This approach is very attractive in that by adding a few primi- tives any logic programming system can be turned into a generic constraint logic programming system in which constraint solving can

Manuel V. Hermenegildo; Daniel Cabeza Gras; Manuel Carro

1995-01-01

424

Variable structure robust fin control for ship roll stabilization with actuator system  

Microsoft Academic Search

The ship roll stabilization by fin control system with actuator is considered in this paper. Assuming that there exist uncertain parameters and uncertain external perturbations in the ship roll model, a variable structure robust control algorithm for ship roll stabilization system is presented for a class of uncertain systems with the absence of matching assumption in which the uncertainty is

Yansheng Yang; Bo Jiang

2004-01-01

425

System-wide inertial response from fixed speed and variable speed wind turbines  

Microsoft Academic Search

As wind penetration levels on power systems in- crease worldwide, the dynamic characteristics of these systems are changing due to the displacement of synchronous generation. One issue, of particular concern, is the resulting reduction in system inertia. Modern, variable speed wind turbines are con- trolled by power electronics and so do not inherently contribute to the inertial response of the

Lisa Ruttledge; Damian Flynn

2011-01-01

426

Measurement of Trace Gases in the Stratosphere with a Mass Spectrometer System  

Microsoft Academic Search

Measurements of trace gases in the stratosphere were performed with a balloon-borne molecular beam sampling system and mass spectrometer. The sensitivity of the mass spectrometer was extended by a microchannel plate detector system that simultaneously collected ions over a wide range of masses. The microchannel plate detector operates in an ion counting mode. Ions striking the microchannel plate release pulses

Daniel Mark Murphy

1985-01-01

427

Mass discrimination monitoring and intercalibration of dual collectors in noble gas mass spectrometer systems  

NASA Astrophysics Data System (ADS)

Accurate high-precision 40Ar/39Ar ages are limited, in part, by the degree of accuracy and precision of the measurement of the 36Ar atmospheric Ar contamination correction and the mass spectrometer mass fractionation bias (mass discrimination) correction. To improve the measurements of the low-level 36Ar signals, we have implemented digital ion-counting and multicollector data acquisition methods. The switch to the digital ion pulse counting method results in a tenfold improvement in the signal-to-noise ratio relative to analog electron multiplier measurements that are in general use in most 40Ar/39Ar laboratories. The use of ion pulse counting significantly improves low-level signal (36Ar) measurements. The improvement in low-level 36Ar measurements, however, comes at the cost of a reduced dynamic range of the electron multiplier detector, thus requiring the use of an alternate detector at times, such as a Faraday cup or analog multiplier for large signals. In turn, this requires accurate intercalibration of the detectors. Here we present a protocol that addresses these issues, one that closely tracks changes in the mass spectrometer mass discrimination and the detector intercalibration (IC) factor(s) during the time frame of an experiment, thereby improving measurement accuracy. A major advantage of our protocol is that the procedure uses the same aliquots of atmospheric Ar to monitor mass discrimination and detector IC factors, saving a significant amount of measurement time. In addition, this IC protocol may address the cause of reported inaccuracies in the measured isotopic ratio data on the "new" generation multicollector mass spectrometers. Further, we present a "time series protocol" that monitors any temporal drift in the mass spectrometer mass fractionation bias that can occur due to laboratory environmental changes.

Turrin, Brent D.; Swisher, Carl C.; Deino, Alan L.

2010-08-01

428

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

NASA Technical Reports Server (NTRS)

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