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1

General energy change law for systems with variable mass  

Microsoft Academic Search

In this paper the general energy change law for the mechanical systems with variable mass is formulated, starting from the Lagrangian equations for such systems. This law is expressed also in terms of the metric tensor and connected with the corresponding generalized Noether's theorem, from where it is concluded under which conditions the energy conservation is valid. The obtained results

Djordje Mušicki

1999-01-01

2

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

Microsoft Academic Search

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

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

2005-01-01

3

Work-energy theorem for variable mass systems  

Microsoft Academic Search

It is shown that the classical work-energy theorem can be generalized so as to be applicable to open systems, i.e., systems for which there exists an influx or efflux of mass. Some instructive examples are given.

Jack Copeland

1982-01-01

4

Work-energy theorem for variable mass systems  

NASA Astrophysics Data System (ADS)

It is shown that the classical work-energy theorem can be generalized so as to be applicable to open systems, i.e., systems for which there exists an influx or efflux of mass. Some instructive examples are given.

Copeland, Jack

1982-07-01

5

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

ERIC Educational Resources Information Center

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

de Sousa, Celia A.

2012-01-01

6

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

ERIC Educational Resources Information Center

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

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

2012-01-01

7

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

ERIC Educational Resources Information Center

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

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

2012-01-01

8

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

PubMed

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

Pietrzy?ski, G; Thompson, I B; Gieren, W; Graczyk, D; Bono, G; Udalski, A; Soszy?ski, I; Minniti, D; Pilecki, B

2010-11-25

9

Body mass index is related to autonomic nervous system activity as measured by heart rate variability  

Microsoft Academic Search

Autonomic nervous system activity is involved in body weight regulation. We assessed whether the body mass index (BMI) is related to the autonomic nervous system activity as assessed by heart rate variability (HRV). Twenty-five adult normotensive, euglycemic healthy males (M) and females (F) were studied (M\\/F=13\\/12). BMI was assessed in each individual. HRV was assessed and the domains of low

A Molfino; A Fiorentini; L Tubani; M Martuscelli; F Rossi Fanelli; A Laviano

2009-01-01

10

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

Microsoft Academic Search

We present high-speed, three-colour photometry of the eclipsing cataclysmic variables CTCV J1300-3052, CTCV J2354-4700 and SDSS J115207.00+404947.8. These systems have orbital periods of 128.07, 94.39 and 97.52 min, respectively, placing all three systems below the observed 'period gap' for cataclysmic variables. For each system we determine the system parameters by fitting a parametrized model to the observed eclipse light curve

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

2011-01-01

11

Newton's law of motion for variable mass systems applied to capillarity  

Microsoft Academic Search

The standard Newton's equation of motion for variable masses is set up and solved to describe the time-dependent rise of a liquid in a capillary tube. The findings in the nonviscous case are also supported by quantitative estimates of the potential energy changes suffered by the interfacial films. The theoretical oscillations in the viscous case are confirmed experimentally for tubes

V. J. Menon; D. C. Agrawal

1987-01-01

12

Are particle rest masses variable: Theory and constraints from solar system experiments  

Microsoft Academic Search

Particle rest mass variation in spacetime is considered. According to Dicke, if this is the case various null experiments indicate that all masses vary in the same way. Their variation relative to the Planck-Wheeler mass defines a universal scalar rest-mass field. We construct the relativistic dynamics for this field based on very general assumptions. In addition, we assume Einstein's equations

Jacob Bekenstein

1977-01-01

13

The Equation of Motion for Relativistic Particles and Systems with a Variable Rest Mass  

Microsoft Academic Search

If the rest mass is constant the equation of motion may be presented in the form: force equals time rate of change in momentum. However, if the rest mass varies because there is an influx or or efflux of mass, the equation of motion may include additional terms to account for the momentum flux. These terms are derived by applying

Kalman B. Pomeranz

1964-01-01

14

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

15

Synthesis Of Attitude Motion Of Variable Mass Coaxial Bodies  

Microsoft Academic Search

This work involves the research of a motion of a mechanical system consisting from coaxial bodies of variable mass in a translating coordinate system. The author gives a theorem on the change in the angular momentum of a system of variable mass coaxial bodies with respect to translating axes. The dynamic equations of motion are constructed using the example of

ANTON V. DOROSHIN

16

Variable mass energy transformation and storage (VMETS) system using NH 3–H 2O as working fluid. Part 2: Modeling and simulation under partial storage strategy  

Microsoft Academic Search

This paper is the second part of our study on a new variable mass energy transformation and storage (VMETS) system using NH3–H2O as working fluid. In the previous study, the working principle and flow of the new system have been introduced, whilst the dynamic models of the new system have been developed and the simulation under the full storage strategy

S. M. Xu; L. Zhang; J. Liang; R. Du

2007-01-01

17

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

18

Variable mass energy transformation and storage (VMETS) system using NH 3–H 2O as working fluid, Part 1: Modeling and simulation under full storage strategy  

Microsoft Academic Search

This paper presents a new variable mass energy transformation and storage (VMETS) system using ammonia–water solution (NH3–H2O) as working fluid. The system has a wide range of working temperature. It can be used to shift load with a diurnal energy storage system for cooling in summer, heating in winter, or hot water supplying all year long. It can also be

S. M. Xu; L. Zhang; J. Liang; R. Du

2007-01-01

19

Variable addressability imaging systems  

NASA Astrophysics Data System (ADS)

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

Kubala, Kenneth Scott

20

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

2013-09-20

21

Smart variable stiffness control systems  

NASA Astrophysics Data System (ADS)

This paper presents a new and innovative semi-active variable stiffness tuned mass damper (SAIVS-TMD). The system has the distinct advantage of retuning in real time thus making the system robust to changes in building stiffness and damping, whereas the passive tuned mass damper (TMD) can only be tuned to a fixed frequency. The SAIVS-TMD is based on a novel semi-active variable stiffness control (SAIVS) device. SAIVS system requires nominal power for operation as compared to active tuned mass dampers. The SAIVS-TMD is retuned using a new control algorithm based on instantaneous frequency estimation using Hilbert transform and short-time Fourier transform (STFT). An analytical model of a three-story structure with SAIVS-TMD is developed. Numerical simulations are performed using the analytical model. The system is implemented in a 1:10 scale three-story scale model in real time using a digital signal processing system and controller. Shake table test results of the system with the SAIVS-TMD are presented. It is shown that the SAIVS-TMD is very effective in reducing the response and providing retuning capability when the building stiffness changes, whereas the TMD is mistuned and loses its effectiveness. Analytical modeling and comparisons between analytical and experimental results are also presented.

Nagarajaiah, Satish; Varadarajan, Nadathur

2001-07-01

22

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

SciTech Connect

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

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

2011-07-10

23

The period gap and masses of cataclysmic variables  

NASA Astrophysics Data System (ADS)

Consequences of the currently-favored view that the cataclysmic variable period gap results from a sharp decrease in orbital braking once the secondary becomes fully convective are examined. It is shown that the period distribution of systems near the edge of the gap imposes, for a given stellar model, tight constraints on the parameters of the Mestel-Spruit magnetic braking law. The white dwarf mass M1 in systems such as TU Men or YZ Cnc must be high, unless these systems are assumed coincidentally to have been born close to the upper edge of the gap. With the present adopted parameters, M1 of not less than 1 solar mass is predicted for both systems. Observational mass determination for these systems and those which should be discovered by Rosat thus offer a stringent test of current theories of the period gap. It is shown that, depending on the secondary mass and age when it first comes into contact, evolution can be driven by angular momentum losses either through magnetic braking or gravitational radiation, and that for periods greater than 2.5-2.6 h, high mass transfer rates are possible, as observed in V795 Her.

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

1991-08-01

24

A variable dispersion array detector for a tandem mass spectrometer  

NASA Astrophysics Data System (ADS)

Incorporation of a pair of quadrupole lenses and one octapole lens after the second magnetic field of a JEOL HX110/HX110 tandem mass spectrometer permits varying the dispersion and therefore the mass range that can be focused on a 2 in array detector. This range can be adjusted from a value of 1: 1.04 to 1: 1.3 for the ratio of low m/z to high m/z falling at the extremes of the detector. The ratio is governed by the d.c. potentials on the lenses which also changes the angle of the resulting focal plane and thus requires that the position of the array detector must be changed accordingly. In the system described, all these variables are under computer control and can be adjusted within 1 s, thus allowing for a change even during the recording of a spectrum if one wishes to minimize the number of segments to be recorded to cover the entire spectrum while still maintaining unit mass resolution. The variable range array detector is useful for the recording of normal mass spectra as well as those generated upon collision induced decomposition (CID) of precursor ions. In the latter case, the refocusing of the ion beams through the quadrupole lens system is more complex but the software controls the lens potentials accordingly. The system has been used to record the normal or CID spectra of peptides, either from a static sample or eluting from a high performance liquid chromatograph.

Hill, James A.; Biller, James E.; Biemann, Klaus

1991-12-01

25

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 made this region of the spectrum much more accessible. Investigating CVs in the IR contributes to our understanding of the properties of key system components that radiate strongly at these wavelengths: the cool outer disk, accretion stream, and secondary star. 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 (detection limits are approximately 0.8 mag fainter). This data will provide the first homogeneous and complete sample of infrared photometry for CVs. We present an analysis of the group IR properties of the approximately 175 CVs currently detected by 2MASS and included in the 2nd Incremental Data Release (March 2000), which covers approximately 50% of the sky. We also provide a comparison of the homogeneous 2MASS JHK magnitudes of these CVs with other published IR magnitudes (where available). The final product of this project will incorporate an IR catalog and atlas 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 Duerbeck, Downes & Shara, and Downes et al.).

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

2001-05-01

26

A variable acceleration calibration system  

NASA Astrophysics Data System (ADS)

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

Johnson, Thomas H.

27

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

28

Mass-losing Semiregular Variable Stars in Baade's Windows  

NASA Astrophysics Data System (ADS)

By cross-correlating the results of two recent large-scale surveys, the general properties of a well-defined sample of semiregular variable stars have been determined. ISOGAL mid-infrared photometry (7 and 15 ?m) and MACHO V and R light curves are assembled for approximately 300 stars in the Baade's windows of low extinction toward the Galactic bulge. These stars are mainly giants of late M spectral type, evolving along the asymptotic giant branch (AGB). They are found to possess a wide and continuous distribution of pulsation periods and to obey an approximate logP-Mbol relation or set of such relations. Approximate mass-loss rates M in the range of ~1×10-8 to 5×10-7 Msolar yr-1 are derived from ISOGAL mid-infrared photometry and models of stellar spectra adjusted for the presence of optically thin circumstellar silicate dust. Mass-loss rates depend on luminosity and pulsation period. Some stars lose mass as rapidly as short-period Mira variables but do not show Mira-like amplitudes. A period of 70 days or longer is a necessary but not sufficient condition for mass loss to occur. For AGB stars in the mass-loss ranges that we observe, the functional dependence of mass-loss rate on temperature and luminosity can be expressed as M~T?L?, where ?=-8.80+0.96-0.24 and ?=+1.74+0.16-0.24, in agreement with recent theoretical predictions. If we include our mass-loss rates with a sample of extreme mass-losing AGB stars in the Large Magellanic Cloud and ignore T as a variable, we get the general result for AGB stars that M~L2.7, valid for AGB stars with 10-8

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

2001-05-01

29

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

30

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

31

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

32

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

33

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

34

Guide to transverse projections and mass-constraining variables  

NASA Astrophysics Data System (ADS)

This paper seeks to demonstrate that many of the existing mass-measurement variables proposed for hadron colliders (mT, meff, mT2, missing p?T, hT, s^min?, etc.) are far more closely related to each other than is widely appreciated, and indeed can all be viewed as a common mass-bound specialized for a variety of purposes. A consequence of this is that one may understand better the strengths and weaknesses of each variable, and the circumstances in which each can be used to best effect. In order to achieve this, we find it necessary first to revisit the seemingly empty and infertile wilderness populated by the subscript “T” (as in “p?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 “?” from “?” or from “?,” and “early projection” from “late projection,” will find their efforts rewarded towards the end of the paper with (i) a better understanding of how collider mass variables fit together, (ii) an appreciation of how these variables could be generalized to search for things more complicated than supersymmetry, (iii) will depart with an aversion to thoughtless or naïve use of the so-called transverse methods of any of the popular computer Lorentz-vector libraries, and (iv) will take care in their subsequent papers to be explicit about which of the 61 identified variants of the “transverse mass” they are employing.

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

2011-11-01

35

Inter- and intra-observer variability in radiologists' assessment of mass similarity on mammograms  

NASA Astrophysics Data System (ADS)

The purpose of this study was to compare the performances of two recently-developed image retrieval methods for mammographic masses, and to investigate the inter- and intra-observer variability in radiologists' assessment of mass similarity. Method 1 retrieved masses that are similar to a query mass from a reference library based on radiologists' margin and shape descriptions and the mass size. Method 2 used computer-extracted features. Two MQSA radiologists participated in an observer study in which they rated the similarity between 100 query masses and the retrieved lesions based on margins, shape, and size. For each query mass, three masses retrieved using Method 1 and three masses retrieved using Method 2 were displayed in random order using a graphical user interface. A nine-point similarity rating scale was used, with a rating of 1 indicating lowest similarity. Each radiologist repeated the readings twice, separated by more than three months, so that intra-observer variability could be studied. Averaged over the two radiologists, two readings, and all masses, the mean similarity ratings were 5.59 and 5.57 for Methods 1 and 2, respectively. The difference between the two methods did not reach significance (p>0.20) for either radiologist. The intra-observer variability was significantly lower than the inter-observer variability, which may indicate that each radiologist may have their image similarity criteria, and the criteria may vary from radiologist to radiologist. The understanding of the trends in radiologists' assessment of mass similarity may guide the development of decision support systems that make use of mass similarity to aid radiologists in mammographic interpretation.

Sahiner, Berkman; Hadjiiski, Lubomir M.; Chan, Heang-Ping; Cui, Jing; Paramagul, Chintana; Nees, Alexis; Helvie, Mark

2009-02-01

36

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

37

Triggering eruptive mass ejection in luminous blue variables  

NASA Astrophysics Data System (ADS)

We study the runaway mass loss process of major eruptions of luminous blue variables (LBVs) stars, such as the 1837-1856 Great Eruption of ? Carinae. We follow the evolution of a massive star with a spherical stellar evolution numerical code. After the star exhausted most of the hydrogen in the core and had developed a large envelope, we remove mass at a rate of 1M?year from the outer envelope for 20 years. We find that after removing a small amount of mass at a high rate, the star contracts and releases a huge amount of gravitational energy. We suggest that this energy can sustain the high mass loss rate. The triggering of this runaway mass loss process might be a close stellar companion or internal structural changes. We show that a strong magnetic field region can be built in the radiative zone above the convective core of the evolved massive star. When this magnetic energy is released it might trigger a fast removal of mass, and by that trigger an eruption. Namely, LBV major eruptions might be triggered by magnetic activity cycles. The prediction is that LBV stars that experience major eruptions should be found to have a close companion and/or have signatures of strong magnetic activity during or after the eruption.

Harpaz, Amos; Soker, Noam

2009-08-01

38

Validation of GRACE time variable gravity against atmospheric mass variations  

NASA Astrophysics Data System (ADS)

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 an area of greater than 2× 10^5 km^2 where the integral of all surface mass changes can be constrained with an accuracy better than 1 cm of water thickness equivalent. As it would be difficult to constrain the hydrology and precipitation signals in a typical region with sufficient accuracy, we Cal/Val GRACE in relatively water-free areas where the atmospheric pressure can be well constrained. We present results of the Cal/Val of GRACE satellite data in the desert of southwestern Egypt. This extremely dry region has several barometers and rain gauges within or nearby. The gravity variation measured by GRACE in the selected area will be the sum of contributions from the GRACE measurement error, the error in removing the atmospheric mass variation using geopotential heights from an ECMWF global circulation model, the fluctuation of water mass in the Nile river and Lake Nasser, aquifer depletion, and sea surface variations in surrounding seas. In general, only the atmospheric mass variation will be significant at the 1 cm level of water thickness equivalent within the Cal/Val area. Simulations indicate that other signals besides the atmosphere should contribute negligibly to the time variable gravity measured by GRACE. To approximate the error in removing atmospheric mass distribution from GRACE data, we calculate the difference between surface pressure from barometer measurements and modeled surface pressure from ECMWF, averaged over periods of GRACE monthly estimates of geoid. We will compare residual differences with the signal measured by GRACE. Further, we will examine errors in the ECMWF numerical model outputs, particularly in the polar regions and over the southern hemisphere where the GCM assimilates very sparse in situ measurements. Atmospheric refractivity structure derived from GPS occultations is very sensitive to geopotential height, and unlike most available atmospheric pressure measurements, occultation data are not assimilated into ECMWF and so are completely independent of the model outputs. We will show preliminary results comparing geopotential heights from SAC-C and CHAMP occultation data with geopotential heights from GCMs.

Velicogna, I.; Wahr, J.; Hajj, G.

2003-04-01

39

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

40

Variability of water masses in the western Indian Ocean  

NASA Astrophysics Data System (ADS)

In 1987, conductivity-temperature-depth and current data were collected in two oceanographic surveys carried out around the Indian Ocean coral atolls of Aldabra (46° 20' E, 9° 25' S) and Cosmoledo (47° 30' E, 9° 45' S) between April and July. During the surveys, significant changes were observed in the temperature and salinity of the upper layers. From temperature-salinity analysis, the dominant water masses in the upper layers (0-400 m) were categorized and their origin determined. During the first cruise, TS characteristics changed only slightly. Low salinity waters (S = 34.5-34.6 and T = 28°-30°C), brought from the east by the South Equatorial Current, were dominant in the surface layers. During the second cruise, the surface waters were saltier and cooler (S = 35.1 and T = 25°-26°C) and more homogeneous in the upper 200 m as a result of a greater admixture of a southern water mass. Seasonal cooling at this time was responsible for a deeper surface mixed layer. Near the end of the cruise, TS conditions changed suddenly due to an invasion of southern subtropical water masses in the layers above 200 m. Current meter records were dominated by the regional 50-day oscillation and higher-frequency variability and did not show the expected increase in strength of the South Equatorial Current to indicate onset of the southwest monsoon. The water mass changes were not correlated with changes in the local currents and were probably caused by advection of patches by the large-scale flow.

Morales, Ruben A.; Barton, Eric D.; Heywood, Karen J.

1996-06-01

41

Pulsation-Driven Mass Loss in Luminous Blue Variables  

NASA Astrophysics Data System (ADS)

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

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

2005-09-01

42

Validation of GRACE Time Variable Gravity Against Atmospheric Mass Variations  

NASA Astrophysics Data System (ADS)

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. The data delivered by GRACE will need to be calibrated and validated in order to ensure their quality and reliability. The Calibration/Validation (Cal/Val) phase will validate the data collected during the on-orbit checkout phase and verify the quality of the data for the entire life span of the mission. In order to Cal/Val GRACE data, we must select an area of greater than 2x 105 km^2$ where the integral of all surface mass changes can be constrained with an accuracy better than 1 cm of water thickness equivalent. As it would be difficult to constrain the hydrology and precipitation signals in a typical region with sufficient accuracy, we Cal/Val GRACE in relatively water-free areas where the atmospheric pressure can be well constrained. We present the results of the Cal/Val of GRACE satellite data in the desert of southwestern Egypt. This extremely dry region has several barometers and rain gauges within or nearby. The gravity variation measured by GRACE in the selected area will be the sum of contributions from the GRACE measurement error, the error in removing the atmospheric mass variation using geopotential heights from an ECMWF global circulation model, the fluctuation of water mass in the Nile river and Lake Nasser, aquifer depletion, and sea surface variations in surrounding seas. In general, only the atmospheric mass variation will be significant at the 1 cm level of water thickness equivalent within the Cal/Val area. Simulations indicate that the other signals besides the atmosphere should contribute negligibly to the time variable gravity measured by GRACE.To approximate the error in removing atmospheric mass distribution from GRACE data, we calculate the difference between surface pressure from barometer measurements and modeled surface pressure from ECMWF, averaged over periods of GRACE monthly estimates of geoid. We will compare residual differences with the signal measured by GRACE. If the two signals are significantly different we will investigate if the fluctuation of water mass in the area can be responsible for the observed discrepancy.

Velicogna, I.; Wahr, J.

2002-12-01

43

Automatic mass spectrometer inlet system  

SciTech Connect

There is provided a mass spectrometer having a gas inlet system for introducing a sample into the ion source of the spectrometer which inlet system includes a cold trap for condensing a sample. The inlet system is provided with means for detecting the pressure therein and means for automatically controlling the operation of the cold trap in dependence on the detected pressure whereby the sample is automatically condensed in the cold trap when it is present in a small quantity. Around the cold trap is conveniently a coolant passage through which coolant from a coolant reservoir is drawn.

Barrie, A.; Freedman, P.A.

1985-01-22

44

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

45

Possible mass distributions in the nebulae of other solar systems  

Microsoft Academic Search

Mass distributions of other solar nebulae are calculated using the supernova shell fragmentation model of solar system formation. The variable a, expressing the ratio of shear flow to the rotation of the supernova star, is found to be crucial to the shape of the mass distributions, though the limits on a are not well established and the range of a

Wilbur K. Brown

1987-01-01

46

Variability of Southern Ocean water masses controlled by wind-driven advection  

NASA Astrophysics Data System (ADS)

Detection of long-term climate change requires knowledge of natural variability in the ocean-atmosphere system. In the Southern Ocean, climate variability is evident on time-scales of days to centuries. A dominant mode of variability is, however, interannual to decadal. In this talk I examine what controls the variability of Subantarctic Mode Water (SAMW), a water-mass formed on the equatorward side of the Antarctic Circumpolar Current. South of Australia, observed SAMW temperature and salinity anomalies seem to occur in phase and are thus unlikely to be controlled by variations in air-sea heat/freshwater exchange. Experiments with a coupled climate model suggest the observations south of Australia are typical of the Subantarctic Zone. In particular, we find that SAMW T-S variability is controlled by ocean transport changes, mainly variations in the equatorward Ekman transport of cool, fresh water across the Subantarctic Front. In contrast, air-sea heat flux anomalies are mostly a response to changes in SST. This is quite unlike the traditional view that water-mass variability is controlled by air-sea heat exchange.

England, M.; Rintoul, S.

2001-05-01

47

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

48

Extraction of energy by a variable mass plate from an explosive charge  

Microsoft Academic Search

This paper shows how the motion of plates with variable and constant mass is different. An equation of motion of a body with variable mass is presented which takes into account the decrease in the velocity after the collision. The authors explain how the work performed by the explosion products on a plate with increasing mass does not equal the

T. I. Karmanova; B. G. Loboiko

1987-01-01

49

Moving mass trim control system design  

Microsoft Academic Search

This paper describes the design of a moving mass trim control system for maneuvering axisymmetric reentry vehicles. The moving mass trim controller is composed of three equal masses that are independently positioned in order to deliver a desired center of mass position. For a slowly spinning reentry vehicle, the mass offset creates a trim angle-of-attack to generate modest flight path

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

1996-01-01

50

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

51

Variable refrigerant flow systems: A review  

Microsoft Academic Search

This review study presents a detailed overview of the configurations of the outdoor and indoor units of a multi-split variable refrigerant flow (VRF) system, and its operations, applications, marketing and cost. Besides, a detailed review about the experimental and numerical studies associated with the VRF systems is provided. The aim is to put together all the diversified information about the

Tolga N. Aynur

2010-01-01

52

The Evolution of Low Mass Stars in Close Binary Systems  

Microsoft Academic Search

We report on our extensive investigation of the evolution of low mass stars in close binary systems with white dwarfs. Cataclysmic variables (CVs), which are the most numerous UV and X-ray sources in the Galaxy, and Type Ia supernovae, which are standard candles for cosmology, are believed to be the end products of these close binary systems, but little is

N. M. Silvestri; S. L. Hawley; P. Szkody; J. J. Bochanski; A. A. West; O. J. Fraser; K. R. Covey; M. A. Wolfe; K. M. Vanlandingham; L. C. Dang

2004-01-01

53

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

54

A Computer System for Intraspecies Biologic and Behavioral Variability Studies.  

National Technical Information Service (NTIS)

An analytical system is described for the computer analysis of variables pertinent to the study of intraspecies biologic and behavioral variability. This program can be used for the selection of appropriate variables, for predicting which variables should...

N. A. Sidley D. C. Brown S. P. Stackhouse

1966-01-01

55

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

56

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

57

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

USGS Publications Warehouse

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

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

2000-01-01

58

Mobile Variable Depth Sampling System Design Study  

SciTech Connect

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

BOGER, R.M.

2000-08-25

59

Hybrid-Entanglement in Continuous Variable Systems  

Microsoft Academic Search

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

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

2010-01-01

60

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

NASA Astrophysics Data System (ADS)

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

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

2003-12-01

61

Variable phaseplates for focus invariant optical systems  

NASA Astrophysics Data System (ADS)

Depth of focus can be enhanced with cubic phaseplates located at the exit pupil of an optical system without significant loss of resolution. The enhancement factor is proportional to the strength of the phaseplate. The digital image is inversely filtered. The stronger the phaseplate is the stronger the inverse filter function must be. This causes increasing noise for high spatial frequencies in the restored image. Therefore, an optimum strength of the cubic phaseplate has to be chosen for the respective situation. A variable phaseplate system has been realized and tested. The performance of the setup has been experimentally studied. Applications and practical aspects are discussed in particular regarding barcode readers.

Hellmuth, T.; Bich, A.; Börret, R.; Holschbach, A.; Kelm, A.

2005-09-01

62

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

NASA Astrophysics Data System (ADS)

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

Sakai, Tadashi

63

Possible mass distributions in the nebulae of other solar systems  

NASA Astrophysics Data System (ADS)

Mass distributions of other solar nebulae are calculated using the supernova shell fragmentation model of solar system formation. The variable a, expressing the ratio of shear flow to the rotation of the supernova star, is found to be crucial to the shape of the mass distributions, though the limits on a are not well established and the range of a may have been overestimated. Disc mass distributions are calculated with the SOLSYS program (Brown and Gritzo, 1987) for various values of (b/r)tan theta, in which 2b is the height and r is the radius of the cylindrical fragment.

Brown, Wilbur K.

1987-03-01

64

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

SciTech Connect

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

Cronin, M.J.

1984-07-31

65

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

SciTech Connect

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

Cronin, M. J.

1985-10-15

66

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

67

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

68

Optical Variability Timescales in Seyfert Galaxies: Relationships with Black Hole Mass and Luminosity  

NASA Astrophysics Data System (ADS)

The Lick AGN Monitoring Project (LAMP) targeted 13 nearby Seyfert 1 galaxies with the goal of measuring their black hole masses using reverberation mapping. The AGNs in the sample were selected to have black holes with masses between 106 and 3*107 solar masses. In order to measure the AGN continuum variability, we obtained broad-band B and V images on most nights from February through May 2008. Having regularly sampled light curves with a daily cadence over the course of a few months not only is useful for obtaining the broad-line reverberation lag and black hole mass, but also allows us to examine the characteristics of the continuum variability. Using the light curve data, we measured variability structure functions and determined the characteristic break timescales. Combining our results with previous results from the literature for higher-mass reverberation-mapped AGNs, we find that the characteristic timescale is strongly correlated with both black hole mass and AGN luminosity. We derive a new relationship between characteristic timescale, black hole mass, and luminosity that fits the properties of Seyfert galaxies and quasars over nearly four orders of magnitude in black hole mass. Such a relationship can provide a new method for estimating black hole masses in Seyfert galaxies and quasars using optical light curves measured from future synoptic variability surveys.

Walsh, Jonelle; LAMP Collaboration

2009-05-01

69

Moving mass trim control system design  

SciTech Connect

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

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

1996-03-01

70

Mass spectrometry of steroid systems  

Microsoft Academic Search

The mass spectra of epimeric secondary and tertiary alcohols of the series of 3-tert-butyl-4-methoxy-cyclohexanol was studied. The alcohols in the cis-l, 4-OH\\/H configuration are considerably more easily dehydrated under electron impact than their trans-1, 4-OH\\/H epimers.

V. S. Bul'fson; V. I. Zaretskii; V. G. Zaikin; A. A. Akhrem; A. V. Kamernitskii; A. M. Prokhoda

1968-01-01

71

Separability criteria for continuous-variable systems  

NASA Astrophysics Data System (ADS)

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

Fujikawa, Kazuo

2009-07-01

72

Equilibrium statistical mechanics of relativistic particles with variable masses. I. Nonquantal theory  

Microsoft Academic Search

The necessity for statistical mechanics of relativistic particles endowed with variable rest masses essentially arises from astrophysics (when dealing with clusters of stars or galaxies which do exhibit a mass spectrum) and from the statistical bootstrap model of Hagedorn and Frautschi for inclusive reactions of elementary particles. We begin this series with the simplest case of classical particles since this

Rémi Hakim

1974-01-01

73

A mass conservative and water storage consistent variable parameter Muskingum-Cunge approach  

Microsoft Academic Search

The variable parameter Muskingum-Cunge (MC) flood routing approach, together with several variants proposed in the literature, does not fully preserve the mass balance, particularly when dealing with very mild slopes (<10-3). This paper revisits the derivation of the MC and demonstrates (i) that the loss of mass balance in MC is caused by the use of time variant parameters which

E. Todini

2007-01-01

74

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

75

MASS: An automated accountability system  

SciTech Connect

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

Erkkila, B.H.; Kelso, F.

1994-08-01

76

Infrared properties of cataclysmic variables from 2MASS: Results from the 2nd incremental data release  

NASA Astrophysics Data System (ADS)

Because accretion-generated luminosity dominates the radiated energy of most cataclysmic variables (CVs), they have been ``traditionally'' observed primarily at short wavelengths. Infrared (IR) observations of CVs contribute to the understanding of key system components that are expected to radiate at these wavelengths, such as the cool outer disk, accretion stream, and secondary star. We have compiled the J, H, and Ks photometry of all CVs located in the sky coverage of the 2 Micron All Sky Survey (2MASS) 2nd Incremental Data Release. This data comprises 251 CVs with reliably identified near-IR counterparts and S /N >10 photometry in one or more of the three near-IR bands.

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

2002-01-01

77

Video-on-Demand System Using Optical Mass Storage System  

Microsoft Academic Search

Digital video-on-demand systems based on high-speed digital networks and video compression techniques have been proposed recently. One serious problem for these systems is achieving mass storage with quick access. In this paper we propose a video storage hierarchy of magnetic disks and an optical mass storage system (MSS). To solve the problems that occur when optical mass storage systems are

Tatsuo Mori; Kazutoshi Nishimura; Hirotaka Nakano; Yutaka Ishibashi

1993-01-01

78

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

SciTech Connect

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

Sirotkin, Fedir V.; Kim, Woong-Tae, E-mail: sirotkin.f.v@gmail.co, E-mail: wkim@astro.snu.ac.k [Department of Physics and Astronomy, FPRD, Seoul National University, Seoul 151-742 (Korea, Republic of)

2010-10-01

79

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

Microsoft Academic Search

A hybrid ion mobility-mass spectrometer (IM-MS) incorporating a variable-temperature (80–400 K) drift tube is presented. The\\u000a instrument utilizes an electron ionization (EI) source for fundamental small molecule studies. Ions are transferred to the\\u000a IM-MS analyzer stages through a quadrupole, which can operate in either broad transmission or mass-selective mode. Ion beam\\u000a modulation for the ion mobility experiment is accomplished by an

Jody C. May; David H. Russell

2011-01-01

80

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

NASA Astrophysics Data System (ADS)

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

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

2012-01-01

81

An analysis of space power system masses  

SciTech Connect

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

1990-01-01

82

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

83

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

84

Mass flow fuel injection control system  

Microsoft Academic Search

A mass flow fuel injection control system is described for an internal combustion engine having air intake means supplying combustion air to the engine, and fuel injector means supplying fuel to the engine. The control system consists of: air flow velocity sensing means comprising venturi means in the air intake means producing a pressure drop, and means measuring the differential

Staerzl

1988-01-01

85

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

NASA Astrophysics Data System (ADS)

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

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

2011-10-01

86

High Temperature Variable Conductance Heat Pipes for Radioisotope Stirling Systems  

NASA Astrophysics Data System (ADS)

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

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

2009-03-01

87

Dynamical limits on dark mass in the outer solar system  

SciTech Connect

Simplified model solar systems with known observational errors are considered in conducting a dynamical search for dark mass and its minimum detectable amount, and in determining the significance of observed anomalies. The numerical analysis of the dynamical influence of dark mass on the orbits of outer planets and comets is presented in detail. Most conclusions presented are based on observations of the four giant planets where the observational errors in latitude and longitude are independent Gaussian variables with a standard deviation. Neptune's long orbital period cannot be predicted by modern ephemerides, and no evidence of dark mass is found in considering this planet. Studying the improvement in fit when observations are fitted to models that consider dark mass is found to be an efficient way to detect dark mass. Planet X must have a mass of more than about 10 times the minimum detectable mass to locate the hypothetical planet. It is suggested that the IRAS survey would have already located the Planet X if it is so massive and close that it dynamically influences the outer planets. Orbital residuals from comets are found to be more effective than those from planets in detecting the Kuiper belt. 35 refs.

Hogg, D.W.; Quinlan, G.D.; Tremaine, S. (Canadian Institute for Theoretical Astrophysics, Toronto (Canada) MIT, Cambridge, MA (USA))

1991-06-01

88

Structures with Semiactive Variable Stiffness Single\\/Multiple Tuned Mass Dampers  

Microsoft Academic Search

This paper proposes application of single and multiple semiactive variable stiffness tuned mass dampers STMD\\/SMTMD for response control of multistory structures under several types of excitation. A new semiactive control algorithm is developed based on real-time frequency tracking of excitation signal by short time Fourier transform. A parametric study is performed in the frequency domain to investigate the dynamic characteristics

Satish Nagarajaiah

2007-01-01

89

A neural network controller for diving of a variable mass autonomous underwater vehicle  

Microsoft Academic Search

In general, traditional controllers used for underwater vehicles are complex, non-adaptive and somewhat slow. On the other hand, it is difficult to accurately determine the hydrodynamic coefficients and the dynamics of underwater vehicles. They are highly nonlinear; therefore, intelligent methods are suitable choice for their control. In this paper, an intelligent neural network method for diving of a variable mass

Mazda Moattari; Alireza Khayatian

2008-01-01

90

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

Microsoft Academic Search

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

X. Carton; P. L'Hegaret

2011-01-01

91

Water Mass Variability in the Rockall Through Using a Numerical Model  

NASA Astrophysics Data System (ADS)

A regional version of ORCA0.5 was integrated over 44 years and used to analyse the water mass variability in the sub-surface at the Rockall Through. The results suggest that the local variability at the surface does not impact the waters at around 750 meters. The diagrams of temperature and salinity were able to determine that the water mass at those depths can be prescribed by a mixing of 2 different water masses, a relatively fresh and cold water from the Labrador Sea region and a relatively warmer and saltier water from the Mediterranean Sea. Temperature and salinity characteristics were also used to track down the path in which these 2 waters masses reach the Rockall Through, clearly showing that the water from the Labrador Sea enters the Rockall Through following the sub-polar gyre, while the water from the Mediterranean Sea has a straight path from the Gulf of Cadiz. In fact, a lagged correlation between the water mass variability and a sub-polar gyre index is very high and coherent at 95%. A comparison between the model results and in-situ observations of salinity and temperature shows that the model results are very robust, suggesting that the knowledge of the dynamics in the region can be improved with a deeper analysis of the model.

Dottori, M.

2009-04-01

92

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

93

A fuzzy sliding mode approach for the two-mass system  

Microsoft Academic Search

This paper presents a new speed control method for a so called two mass system. To achieve a good performance, the state variables are divided into two groups. The sliding surface is designed in a reduced order state-space and the remaining state variables are controlled by a fuzzy method. Two control loops are proposed, the outer angular speed control loop

D. Szabo; S. Kerekes; O. Dranga; T. Gajdar

1999-01-01

94

Digital Squarer System for Positive Mass Identification on the ARL Ion Microprobe Mass Analyser.  

National Technical Information Service (NTIS)

The original analogue squarer for mass scale linearisation in the Ion Microprobe Mass Analyser (IMMA) has been replaced by a programmable digital squarer system which permits reliable mass number identification throughout the tested range 1 to 240. The di...

K. N. Woods L. D. V. Grant E. D. Rawsthorne H. J. Strydom W. H. Gries

1984-01-01

95

Semiactive vibration isolation system with variable stiffness and damping control  

Microsoft Academic Search

Semi-active systems with variable stiffness and damping have demonstrated excellent performance. However, conventional devices for controlling variable stiffness are complicated and difficult to implement in most applications. To address this issue, a new configuration using two controllable dampers and two constant springs is proposed. This paper presents theoretical and experimental analyses of the proposed system. A Voigt element and a

Yanqing Liu; Hiroshi Matsuhisa; Hideo Utsuno

2008-01-01

96

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

97

Wind energy conversion system simulator using variable speed induction motor  

Microsoft Academic Search

The conventional synchronous generator in wind energy conversion system are now getting replaced by variable speed induction generator to extract maximum power with wide range of wind speed limit. The design and performance of such system are required a simplified digital simulator, especially for development of optimal control solutions. The proposed work is to make a prototype of an variable

S. W. Mohod; M. V. Aware

2010-01-01

98

High Temperature Variable Conductance Heat Pipes for Radioisotope Stirling Systems  

SciTech Connect

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

Tarau, Calin; Walker, Kara L.; Anderson, William G. [Advanced Cooling Technologies, Inc. 1046 New Holland Ave. Lancaster, PA 17601 (United States)

2009-03-16

99

Mass and volume-specific views on thermodynamics for open systems  

Microsoft Academic Search

A general framework for the thermodynamics of open systems is presented. The theory is fundamentally based on the generalized balance of mass, which is enhanced by additional surface-flux and volume-source terms. The presentation highlights the influence of the enhanced mass balance on the remaining balance equations. To clarify the impact of the variable reference density, we introduce the notions of

Ellen Kuhl; Paul Steinmann

2003-01-01

100

Australian water mass variations from GRACE data linked to Indo-Pacific climate variability  

NASA Astrophysics Data System (ADS)

Time-variable gravity data from the Gravity Recovery And Climate Experiment (GRACE) mission are used to 22 study total water content over Australia for the period 2002-2010. A time-varying annual signal explains 61% 23 of the variance of the data, in good agreement with two independent estimates of the same quantity from 24 hydrological models. Water mass content variations across Australia are linked to Pacific and Indian Ocean 25 variability, associated with El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD), 26 respectively.From1989,positive(negative)IODphaseswererelatedtoanomalouslylow(high)precipitation 27 in southeastern Australia, associated with a reduced (enhanced) tropical moisture flux. In particular, the 28 sustained water mass content reduction over central and southern regions of Australia during the period 29 2006-2008 is associated with three consecutive positive IOD events. Acknowledgments: We thank the research project for emergent groups from the University of Alicante, GRE10-13.

Garcia-Garcia, D.; Ummenhofer, C. C.; Zlotnicki, V.

2011-12-01

101

The Research about the Derivation and the Applicability of the Aircraft Four Control Variables Point Mass Model  

Microsoft Academic Search

A new point mass model of the air vehicle has been developed in our laboratory. This model employs angle-of-attack, side slip angle, bank angle and thrust, as four control variables. The existent three control variables point mass model cannot introduce the winds and active side slip angle control, while this new model can introduce them. This paper explains about the

Fumiaki Imado; Yuki Heike; Takuya Kinoshita

2009-01-01

102

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

Microsoft Academic Search

The 68 000 I-band light curves of variable stars detected by the OGLE survey in the Large and Small Magellanic Clouds (MCs) are fitted by Fourier series, and also correlated with the DENIS and 2MASS all-sky release databases and with lists of spectroscopically confirmed M-, S- and C-stars. Lightcurves and the results of the lightcurve fitting (periods and amplitudes) and

M. A. T. Groenewegen

2004-01-01

103

Interannual variability of water masses transports across A25-OVIDE section (subpolar atlantic gyre)  

NASA Astrophysics Data System (ADS)

The Ovide (Observatoire de la Variabilité Interannuelle à DEcennale) project has consisted on repeated trans-oceanic hydrographic section from Greenland to Portugal every other year (from 2002 to 2010). This project is part of the CLIVAR (Climate Variability and Predictability) and CARBOOCEAN international programs, both focused on ocean climate variability. The section crosses the main currents implicated in the North Atlantic Meridional Overturning Circulation (MOC), and is very close to the previous A25 section ("Fourex") of the WOCE (World Ocean Circulation Experiment) performed in 1997. The North Atlantic Ocean plays a crucial role in the global thermohaline circulation as can be considered the departure point of the MOC, where the warm salty waters are transformed by deep winter convection into deep waters. The water mass distribution in the section is derived by means of OMP method for every cruise, and then combined with absolute velocity fields to provide the relative contribution from each water mass to the final transport values. The water mass circulation pattern across the section is then discussed within the context of interannual variability of the main MOC components, in terms of the different water mass components. The mean transport for each of these water masses results in 11.7 ± 2.6 Sv (1 Sv = 106 m3 s-1) for central waters, 2.0 ± 0.69 Sv for SubArtic Intermediate Water, 0.58 ± 0.51 Sv for Antartic Intermediate water and MW 0.15 ± 1.3 Sv, all of them flowing northward and contributing to the upper branch of the MOC. On other hand, the lower MOC branch transports southward -8.5 ± 2.0 Sv of LSW, -3.3 ± 0.33 Sv of Iceland-Scotland Overflow Water and -1.3 ± 0.92 Sv of Denmark Strait Overflow Water, with an almost zero net transport of North East Atlantic Deep Water of 0.17 ± 1.0 Sv. The knowledge of the variability and contribution of each water mass itself will allow a better understanding of the global circulation mechanisms in the subpolar intergyre region, which is the connection between the North Atlantic Oscillation (NAO) atmospheric forcing and the changes in production and/or advection of main water masses.

Carracedo, L. I.; García, M.; Mercier, H.; Conde, P.; Lherminier, P.; Pérez, F. F.; Gilcoto, M.

2012-04-01

104

Frequency Regulation Contribution Through Variable-Speed Wind Energy Conversion Systems  

Microsoft Academic Search

This paper presents a new method to enhance the participation of variable-speed wind energy conversion systems (WECS) in existing frequency regulation mechanisms. The proposed approach, based on a modified inertial control scheme, takes advantage of the fast response capability associated with electronically-controlled WECS, allowing the kinetic energy stored by rotational masses to be partly and transiently released in order to

Juan Manuel Mauricio; Alejandro Marano; Antonio Gomez-Exposito; JosÉ Luis Martinez Ramos

2009-01-01

105

Excess Vitamin Intake before Starvation does not Affect Body Mass, Organ Mass, or Blood Variables but Affects Urinary Excretion of Riboflavin in Starving Rats  

PubMed Central

B-vitamins are important for producing energy from amino acids, fatty acids, and glucose. The aim of this study was to elucidate the effects of excess vitamin intake before starvation on body mass, organ mass, blood, and biological variables as well as on urinary excretion of riboflavin in rats. Adult rats were fed two types of diets, one with a low vitamin content (minimum vitamin diet for optimum growth) and one with a sufficient amount of vitamins (excess vitamin diet). Body mass, organ mass, and blood variables were not affected by excess vitamin intake before starvation. Interestingly, urinary riboflavin excretion showed a different pattern. Urine riboflavin in the excess vitamin intake group declined gradually during starvation, whereas it increased in the low vitamin intake group. Excess vitamin intake before starvation does not affect body mass, organ mass, or blood variables but does affect the urinary excretion of riboflavin in starving rats.

Moriya, Aya; Fukuwatari, Tsutomu; Shibata, Katsumi

2013-01-01

106

A comparison of trajectory and air mass approaches to examine ozone variability  

NASA Astrophysics Data System (ADS)

Back trajectory analysis is a commonly-used tool for understanding how short-term variability in surface ozone depends on transport into a given location. Lesser-used but equally effective methods are air-mass based approaches that are primarily driven by changes in temperature and humidity conditions. We compare and combine these two fundamentally different approaches by evaluating daily near-surface afternoon warm-season ozone concentrations from 2001 to 2006 in and around the Shenandoah Valley of Virginia. Analysis of variance is used to compare summer afternoon ozone levels between air masses as identified by the Spatial Synoptic Classification to clusters of 72-h back trajectories estimated by the HYSPLIT model. Ozone concentrations vary significantly across both air masses and trajectory clusters at all ozone monitors. Concentrations are highest for air masses characterized by dry, warm conditions and for air originating from the north and west of the study area or circulating over the mid-Atlantic region. In many cases, the interaction between synoptic types and back trajectory clusters produce results not evident from the examination of simple trajectories or air masses alone. For example, ozone concentrations on Moist Moderate days are 30 ppb higher when air parcels travel moderate distances into the Shenandoah Valley from the west than when they travel longer distances from the north or northeast. Combining air mass and trajectory approaches provides a more useful characterization of air quality conditions than either method alone.

Davis, Robert E.; Normile, Caroline P.; Sitka, Luke; Hondula, David M.; Knight, David B.; Gawtry, Stephen P.; Stenger, Philip J.

2010-01-01

107

Multiple groove variable pitch pulley system  

US Patent & Trademark Office Database

A multiple groove, variable pitch pulley comprises an annular hub threaded about its exterior surface. A stationary end flange is mounted at one end of the hub and a movable end flange is threaded onto the other end of the hub. One or more center flanges are threaded into the hub and lie between the stationary end flange and the movable end flange. The center flanges comprise a disk section and a collar section of lesser diameter than the disk section. The disk section of each center flange and the movable end flange each comprises an axial counterbore for receiving the collar section of an adjacent center flange.

Joanis, Jr.; Marvin A. (Montebello, CA)

1988-02-16

108

Characterizing spatial and temporal variability of dissolved gases in aquatic environments with in situ mass spectrometry.  

PubMed

The TETHYS mass spectrometer is intended for long-term in situ observation of dissolved gases and volatile organic compounds in aquatic environments. Its design maintains excellent low mass range sensitivity and stability during long-term operations, enabling characterization of low-frequency variability in many trace dissolved gases. Results are presented from laboratory trials and a 300-h in situ trial in a shallow marine embayment in Massachusetts, U.S.A. This time series consists of over 15000 sample measurements and represents the longest continuous record made by an in situ mass spectrometer in an aquatic environment. These measurements possess sufficient sampling density and duration to apply frequency analysis techniques for study of temporal variability in dissolved gases. Results reveal correlations with specific environmental periodicities. Numerical methods are presented for converting mass spectrometer ion peak ratios to absolute-scale dissolved gas concentrations across wide temperature regimes irrespective of ambient pressure, during vertical water column profiles in a hypoxic deep marine basin off the coast of California, U.S.A. Dissolved oxygen concentration values obtained with the TETHYS instrument indicate close correlation with polarographic oxygen sensor data across the entire depth range. These methods and technology enable observation of aquatic environmental chemical distributions and dynamics at appropriate scales of resolution. PMID:19673300

Camilli, Richard; Duryea, Anthony N

2009-07-01

109

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

110

Analytic solutions for convective regime flow in a differentially heated vertical slot with variable mass flux  

NASA Astrophysics Data System (ADS)

Recently, K. Buehler (2000) reported special solutions for free convection in a differentially heated vertical slot with varible mass flux through the gap. The variable mass flux can be achieved in practice by placing porous endcaps on the top and bottom of the slot. In this manner one can move continuously from flow through and open slot to flow throug a slot with rigid capped endwalls. We extend Buehler's work for conduction regime flow to convection regime flow by using an empirical relation due to Elder (1965) for the uniform temperature gradient that develops in large aspect ratio cavities. Various features of the solution will be presented, including a criterion for backflow through the slot as a function of the mass flux parameter and the Grashof number.

Weidman, P. D.

2000-11-01

111

Estimation of Mass-Spring-Dumper Systems  

NASA Astrophysics Data System (ADS)

In this chapter a procedure for parameters identification using an algebraic identification method for a continuous time constant linear system is described. A specific application in the determination of the parameters mass-spring-damper system is made. The method is suitable for simultaneously identifying, both, the spring constant and the damping coefficient. It is found that the proposed method is computationally fast and robust with respect to noises. The identification algorithm is verified by simulation results. The estimations are carried out on-line.

Becedas, Jonathan; Mamani, Gabriela; Feliu, Vicente; Sira-Ramírez, Hebertt

112

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

NASA Astrophysics Data System (ADS)

We present the results of X-ray variability and spectral analysis of a sample of 15 new candidates for active galactic nuclei with relatively low-mass black holes (BHs). They are selected from the Second XMM-Newton Serendipitous Source Catalogue based on strong variability quantified by normalized excess variances. Their BH masses are estimated to be (1.1-6.6) × 106 M ? by using a correlation between excess variance and BH mass. Seven sources have estimated BH masses smaller than 2 × 106 M ?, which are in the range for intermediate-mass black holes. Eddington ratios of sources with known redshifts range from 0.07 to 0.46 and the mean Eddington ratio is 0.24. These results imply that some of our sources are growing supermassive black holes, which are expected to have relatively low masses with high Eddington ratios. X-ray photon indices of the 15 sources are in the range of ?0.57-2.57 and 5 among them have steep (>2) photon indices, which are the range for narrow-line Seyfert 1s. Soft X-ray excess is seen in 12 sources and is expressed by a blackbody model with kT ? 83-294 eV. We derive a correlation between X-ray photon indices and Eddington ratios, and find that the X-ray photon indices of about a half of our sources are flatter than the positive correlation suggested previously. Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA.

Kamizasa, Naoya; Terashima, Yuichi; Awaki, Hisamitsu

2012-05-01

113

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

SciTech Connect

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

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

2012-05-20

114

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

1996-01-01

115

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

PubMed

Traditional dual porosity models do not take into account the effect of matrix block size distribution on the mass transfer between matrix and fracture. In this study, we introduce the matrix block size distributions into an advective-diffusive solute transport model of a divergent radial system to evaluate the mass transfer shape factor, which is considered as a first-order exchange coefficient between the fracture and matrix. The results obtained lead to a better understanding of the advective-diffusive mass transport in fractured porous media by identifying two early and late time periods of mass transfer. Results show that fractured rock matrix block size distribution has a great impact on mass transfer during early time period. In addition, two dimensionless shape factors are obtained for the late time, which depend on the injection flow rate and the distance of the rock matrix from the injection point. PMID:22534093

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

2012-03-10

116

A Labelled System for IPL with Variable Splitting  

Microsoft Academic Search

The paper introduces a free variable, labelled proof system for intuitionistic propositional logic with variable splitting.\\u000a In this system proofs can be found without backtracking over rules by generating a single, uniform derivation. We prove soundness,\\u000a introduce a construction that extracts finite countermodels from unprovable sequents, and formulate a branchwise termination\\u000a condition. This is the first proof system for intuitionistic

Roger Antonsen; Arild Waaler

2007-01-01

117

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

118

Cataclysmic Variables and Possible Low-Mass White Dwarfs in the Globular Cluster NGC 6397  

NASA Astrophysics Data System (ADS)

We present photometric and spectroscopic HST observations of cataclysmic variables and a new class of faint ultraviolet (UV) stars in the collapsed-core globular cluster NGC 6397. Color-magnitude diagrams constructed from UBVI images obtained with the WFPC2 reveal seven UV-bright stars that lie between the main sequence and the white dwarf sequence in a U vs. U-B CMD. Four of these are cataclysmic variables (CVs), whose spectra show the emission lines and whose lightcurves show the "flicker" characteristic of accreting binaries. All four have quite faint disks as compared to field CVs, which may imply low accretion rates. Unlike the CVs, the other three UV-bright stars show no photometric variability and have broad-band colors characteristic of B stars. An FOS spectrum we have obtained of one of these non-flickering (NF) stars reveals a broad H-beta line in absorption. Detailed comparisons with stellar atmosphere models yield log g = 6.25 +/- 1.0 and an effective temperature of 17,500 +/- 5,000 K. Using these line parameters and the luminosity of the NF we show that the spectrum is consistent with a helium white dwarf with a mass of about 0.25 solar masses and an age of 0.1-0.5 Gyr. The NF spectrum is significantly Doppler shifted from the expected wavelength, which may imply the presence of a dark, massive companion. We suggest that such low-mass He WDs could be formed when the evolution of a red giant is interrupted, due either to Roche-lobe overflow onto a binary companion, or to envelope ejection following a common-envelope phase in a tidal-capture binary. Both the CVs and the possible He WDs are strongly concentrated toward the cluster center, to the extent that mass segregation from 2-body relaxation alone may be unable to explain their distribution.

Cool, A. M.; Edmonds, P. D.; Grindlay, J. E.

1998-12-01

119

Phytoplankton Scales of Variability in the California Current System: 1. Interannual and Cross-Shelf Variability  

Microsoft Academic Search

In the California Current System, strong mesoscale variability associated with eddies and meanders of the coastal jet play an important role in the biological productivity of the area. To assess the dominant timescales of variability, a wavelet analysis is applied to almost nine years (October 1997 to July 2006) of 1-km-resolution, 5-day-averaged, Sea-viewing Wide Field-of-view Sensor (SeaWiFS) chlorophyll a (chl

Stephanie A. Henson; Andrew C. Thomas

2007-01-01

120

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

Microsoft Academic Search

In the California Current System, strong mesoscale variability associated with eddies and meanders of the coastal jet play an important role in the biological productivity of the area. To assess the dominant timescales of variability, a wavelet analysis is applied to almost nine years (October 1997 to July 2006) of 1-km-resolution, 5-day-averaged, Sea-viewing Wide Field-of-view Sensor (SeaWiFS) chlorophyll a (chl

Stephanie A. Henson; Andrew C. Thomas

2007-01-01

121

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

122

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

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

123

New Constraints on Archean Sulfur Cycling from the Spatial Variability of Mass-Dependent and Mass-Independent Isotopic Signatures  

NASA Astrophysics Data System (ADS)

Sulfur isotope data have been used to provide significant insights into Archean biogeochemical cycling. Small fractionations in ?34S have been used to argue for low sulfate concentrations in the Archean ocean and large, mass-independent (?33S, ?36S) signatures in Archean age strata are one of the most robust indicators for anoxic atmospheric (and oceanic) conditions at this time. These interpretations often rest on data collected from bulk samples (cm- to m-scale) and here we investigate the additional information that can be gained about the operation of the Archean sulfur cycle by analyzing isotopic compositions on much finer spatial scales. In the present study, we make use of secondary ion mass spectrometry (SIMS) on a Cameca 7F/GEO to generate relatively non-destructive sulfur isotope ratio data at high spatial resolution (~1-10µm) using a primary ion beam (Cs+). While SIMS analysis of ?34S variability is not, in itself, new, here we conduct numerous (50 - 500) analyses in a regularly spaced framework over a length scale of just a few mm. This allows for the identification of significant isotopic trends that are not possible to observe using conventional techniques or even by relatively cursory surveys at higher spatial resolution. Specifically, by analyzing samples in a regular grid framework, we can meaningfully link the data from successive measurements, allowing for the identification of ‘long-range’ (e.g., mm-scale) trends. Organizing measurements into a regular grid also provides an additional control on instrument drift (beyond sample-standard bracketing). We demonstrate the power of our approach by examining spatially-coherent sulfide isotope variability in pyritic Archean black shales, which are characterized by multiple successive episodes of sulfidization, each of which possess their own ?34S and ?33S/?36S values. The isotopic variability within given generations of sulfide records information about the physical/biological processes associated with their formation, whereas the isotopic differences between success generations of sulfide precipitation record a picture of environmental change during deposition, early (soft-sedimentary) diagenesis, and late-stage (post-lithification) diagenesis.

Fike, D. A.; Fischer, W. W.

2010-12-01

124

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

125

Variable phaseplates for focus invariant optical systems  

Microsoft Academic Search

Depth of focus can be enhanced with cubic phaseplates located at the exit pupil of an optical system without significant loss of resolution. The enhancement factor is proportional to the strength of the phaseplate. The digital image is inversely filtered. The stronger the phaseplate is the stronger the inverse filter function must be. This causes increasing noise for high spatial

T. Hellmuth; A. Bich; R. Börret; A. Holschbach; A. Kelm

2005-01-01

126

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.

127

Practical robust control of robot arm using variable structure system  

Microsoft Academic Search

The high-gain effect of sliding mode control based on VSS (Variable Structure System) suppresses the uncertainties due to parametric variations, external disturbances and variable payloads. The resulting system is completely robust whereas the obtained control law is simple and easy to be applied to on-line computer control. In this paper, the sliding mode controller for MIMO (Multi-Input Multi-Output) robot arm

F. Harashima; H. Hashimoto; K. Maruyama

1986-01-01

128

Variability in the Flow of Mass & Energy in the Magnetosphere of Saturn  

NASA Astrophysics Data System (ADS)

We present a simple model of the plasma disk surrounding Saturn based on analysis of Cassini CAPS ion data. We derive radial profiles of the distribution of plasma mass, pressure, thermal energy density, and kinetic energy density (as per Bagenal & Delamere, JGR, v.116, A05209, 2011). We estimate the mass outflow rate as well as the net sources and sinks of plasma. We also calculate the total energy budget of the system, estimating the total amount of energy that must be added to the system. We show a factor of 3-5 variation over the 2004 to 2009 period.

Bagenal, Fran; Wilson, R.

2012-10-01

129

Age constraints and fine tuning in variable-mass particle models  

NASA Astrophysics Data System (ADS)

VAMP (variable-mass particle) scenarios, in which the mass of the cold dark matter particles is a function of the scalar field responsible for the present acceleration of the Universe, have been proposed as a solution to the cosmic coincidence problem, since in the attractor regime both dark energy and dark matter scale in the same way. We find that only a narrow region in parameter space leads to models with viable values for the Hubble constant and dark energy density today. In the allowed region, the dark energy density starts to dominate around the present epoch and consequently such models cannot solve the coincidence problem. We show that the age of the Universe in this scenario is considerably higher than the age for noncoupled dark energy models, and conclude that more precise independent measurements of the age of the Universe would be useful in distinguishing between coupled and noncoupled dark energy models.

França, Urbano; Rosenfeld, Rogerio

2004-03-01

130

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

131

Kinematical bounds on jet variables and the heavy jet mass distribution  

NASA Astrophysics Data System (ADS)

We investigate the dependence of the bounds of several QCD jet variables on the order of perturbation theory. We show that the ratio of the heavy jet invariant mass squared to the c.m. energy, MH2/s, is bounded by 1/3 in every order of perturbation theory. To illustrate the consequences, using the recent gluon loop calculations of Ellis et al. we calculate d?/d(MH2/s) to order ?s2 and contrast it with the thrust distribution. It is suggested that the perturbation series for MH2/s converges faster and agrees better with experiment away from the infrared sensitive region.

Clavelli, L.; Wyler, D.

1981-07-01

132

Hawking Radiation of Dirac Particles in a Variable-Mass Kerr Black Hole  

NASA Astrophysics Data System (ADS)

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

Wu, Shuang-Qing; Cai, Xu

2001-04-01

133

Vibration Isolation by a Variable Stiffness and Damping System  

Microsoft Academic Search

Most passive vibration isolation systems are composed of springs and dampers. Although it is possible to improve the isolation performance by active vibration control, the complexity, power requirements and cost of such a system have restricted its use. A vibration isolation system with variable damping is practical and has good performance in the high frequency region, but it was found

Yanqing Liu; Hiroshi Matsuhisa; Hideo Utsuno; Jeong Gyu Park

2005-01-01

134

Variable structure control of nonlinear systems: a new approach  

Microsoft Academic Search

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

Weibing Gao; James C. Hung

1993-01-01

135

A mass conservative and water storage consistent variable parameter Muskingum-Cunge approach  

NASA Astrophysics Data System (ADS)

The variable parameter Muskingum-Cunge (MC) flood routing approach, together with several variants proposed in the literature, does not fully preserve the mass balance, particularly when dealing with very mild slopes (<10-3). This paper revisits the derivation of the MC and demonstrates (i) that the loss of mass balance in MC is caused by the use of time variant parameters which violate the implicit assumption embedded in the original derivation of the Muskingum scheme, which implies constant parameters and at the same time (ii) that the parameters estimated by means of the Cunge approach violate the two basic equations of the Muskingum formulation. The paper also derives the modifications needed to allow the MC to fully preserve the mass balance and, at the same time, to comply with the original Muskingum formulation in terms of water storage. The properties of the proposed algorithm have been assessed by varying the cross section, the slope, the roughness, the space and the time integration steps. The results of all the tests also show that the new algorithm is always mass conservative. Finally, it is also shown that the proposed approach closely approaches the full de Saint Venant equation solution, both in terms of water levels and discharge, when the parabolic approximation holds.

Todini, E.

2007-10-01

136

A mass conservative and water storage consistent variable parameter Muskingum-Cunge approach  

NASA Astrophysics Data System (ADS)

The variable parameter Muskingum-Cunge (MC) flood routing approach, together with several variants proposed in the literature, does not fully preserve the mass balance, particularly when dealing with very mild slopes (<10-3). This paper revisits the derivation of the MC and demonstrates (i) that the loss of mass balance in MC is caused by the use of time variant parameters which violate the implicit assumption embedded in the original derivation of the Muskingum scheme, which implies constant parameters and at the same time (ii) that the parameters estimated by means of the Cunge approach violate the two basic equations of the Muskingum formulation. The paper also derives the modifications needed to allow the MC to fully preserve the mass balance and, at the same time, to comply with the original Muskingum formulation in terms of water storage. The properties of the proposed algorithm have been assessed by varying the cross section, the slope, the roughness, the space and the time integration steps. The results of all the tests also show that the new algorithm is always mass conservative. Finally, it is also shown that the proposed approach closely approaches the full de Saint Venant equation solution, both in terms of water levels and discharge, when the parabolic approximation holds.

Todini, E.

2007-06-01

137

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

138

A Compound Control System of Axial Moving Mass and Aerodynamic Force for Mass Moment Missile  

Microsoft Academic Search

For the mass moment missile in-atmosphere, the principle of moving mass control has been studied with the purpose of finding the major factors that influence attitude motions. On this base, a layout of moving mass and aerodynamic rudder, along with a relative compound control system has been given. The feature of the control system is that the attitude control depends

Yuan Qianchen; Zhang Qingzhen; Zhang Huiping

2011-01-01

139

Modeling the Motion of an Increasing Mass System  

ERIC Educational Resources Information Center

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

Kunkel, William; Harrington, Randal

2010-01-01

140

Application of a Mass Damping System to Bridge Structures.  

National Technical Information Service (NTIS)

The paper studies the tuned mass damping system and the active mass damping system as a means of earthquake protection for highway bridges. It is concluded that an active mass damping system can uniformly reduce the response of a bridge to earthquakes for...

J. M. Kelly K. Hasegawa

1992-01-01

141

Variables  

NSDL National Science Digital Library

This site, presented by Statistics Canada, is a section from "Statistics: Power from Data!" on variable classification. It discusses categorical and numerical variables and their types. The site discusses these variables: nominal, ordinal, numeric, continuous, and discrete. This is a good introductory site for any mathematics classroom studying statistics.

2008-12-25

142

Variable Conductance Heat Pipes for Radioisotope Stirling Systems  

NASA Astrophysics Data System (ADS)

In a Stirling radioisotope system, heat must continually be removed from the GPHS modules, to maintain the GPHS modules and surrounding insulation at acceptable temperatures. Normally, the Stirling convertor provides this cooling. If the Stirling engine stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS, but also ending the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) was designed to allow multiple stops and restarts of the Stirling engine. A VCHP was designed for the Advanced Stirling Radioisotope Generator, with a 850 °C heater head temperature. The VCHP turns on with a ?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 ?T was roughly 70 °C, due to distillation of the NaK in the evaporator.

Anderson, William G.; Tarau, Calin

2008-01-01

143

Variable selection for QSAR by artificial ant colony systems.  

PubMed

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

Izrailev, S; Agrafiotis, D K

144

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

Microsoft Academic Search

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

R. Saravanan

1998-01-01

145

OMCT - New time-series for oceanic mass, angular momentum and sea level variability  

NASA Astrophysics Data System (ADS)

Non-tidal ocean dynamics acting on a wide range of time-scales are imprinted on various geodetic observables including time-variable gravity changes, variations in the Earth's rotation, and changes in sea-level. Independent numerical model estimates, ideally available with short latency, are frequently required to validate, process or interpret those measurements. While OMCT is routinely used to de-aliase short-term non-tidal ocean mass variability in the GRACE gravity field processing for some years now, we here present an updated model version. This configuration is discretized on regular 1° grid with 20 vertical layers, has a time-stepping of 20 min and includes various numerical adjustments that led to an improved mean circulation. As before, OMCT forcing fields consist of wind stress, surface pressure, 2m-temperatures and freshwater fluxes obtained from ECMWF's numerical weather prediction and re-analysis models. Here, variability of an OMCT simulation forced by 6-hourly ECMWF operational analyses that form the basis of the new GRACE AOD product RL05 will be evaluated against data from in-situ ocean bottom pressure and satellite altimetry in order to demonstrate recently achieved improvements with respect to the previously available data series from OMCT.

Dobslaw, H.; Thomas, M.; Bergmann, I.; Esselborn, S.; Flechtner, F.; Zenner, L.

2012-04-01

146

Variable structure control of non-simple input systems  

Microsoft Academic Search

To date the variable structure control (VSC) technique has been used to control systems that are affected by a forcing function that is composed solely of an input u (i.e. simple input systems). However, some systems are affected by forcing functions that are composed of an input plus its derivatives and integrals (i.e. non-simple input systems).A procedure is presented that

G. WALKER

1991-01-01

147

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

Microsoft Academic Search

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

Peter C. Chu; Jae-Hak Lee

2011-01-01

148

Automatic Variable Field Chopper Control System for Electric Railcars  

Microsoft Academic Search

1) The principle of the automatic variable field (AVF) chopper control system, 2) analysis of field characteristics, the field intensity to the chopper-conduction ratio, 3) applying the AVF system to high voltage, large capacity, high frequency chopper equipment, and 4) test results on the Chiyoda Line of Teito Rapid Transit Authority are discussed.

Takashi Kitaoka; Eiichi Ohno; Masahiro Ashiya; Kanzi Katsuki; Takehiko Katta

1977-01-01

149

Seismic Response of Structures with Variable Friction Pendulum System  

Microsoft Academic Search

The dynamic response of a flexible multi-story structure isolated with the variable friction pendulum system (VFPS) under near-fault ground motions is investigated. The fault normal and parallel components are applied in two perpendicular horizontal directions of the isolated system. The frictional forces mobilized at the interface of the VFPS are assumed to be independent of the relative sliding velocity. The

V. R. Panchal; R. S. Jangid

2009-01-01

150

Variable structure control of discrete system with time-delay  

Microsoft Academic Search

A new discrete reaching law which is true of the ldquosix charactersrdquo given by Gao Wei-Bing is introduced in this paper. Then the control law is designed by using the discrete reaching law, and the method how to design a variable structure control of discrete system with time-delay is also introduced; It is manifested that the discrete control system with

De-Wen Zhou; Cun-Chen Gao

2008-01-01

151

A variable buoyancy system for long cruising range AUV  

Microsoft Academic Search

A variable buoyancy system has been developed for long cruising range autonomous underwater vehicle. This paper presents the design, development and testing of the system. Experiments about the characters of the hydraulic pump testing, flow rate testing of flow control valve in deep water, energy consumption of the DC motor in different operating conditions and the precision analysis of the

Wen-de Zhao; Jian-an Xu; Ming-jun Zhang

2010-01-01

152

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

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

153

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

154

The Faint Sky Variability Survey: Searching for Low-Luminosity Cataclysmic Variables and Very Low-Mass Dwarfs  

Microsoft Academic Search

The Faint Sky Variability Survey is a large, deep field, optical, photometric survey using the Wide-Field Camera at the Isaac Newton Telescope on La Palma. Approximately 15 square degrees have been observed photometrically in BVI colors with variability sampling of 10s of minutes to a year. In line with two of the design goals, we are actively searching the photometry

M. E. Huber; S. B. Howell

2001-01-01

155

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

156

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

157

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

158

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

159

Coarse variables of autonomous ODE systems and their evolution  

NASA Astrophysics Data System (ADS)

Given an autonomous system of ordinary differential equations (ODE), we consider developing practical models for the deterministic, slow/coarse behavior of the ODE system. Two types of coarse variables are considered. The first type consists of running finite time averages of phase functions. Approaches to construct the coarse evolution equation for this type are discussed and implemented on a 'Forced' Lorenz system and a singularly perturbed system whose fast flow does not necessarily converge to an equilibrium. We explore two strategies. In one, we compute (locally) invariant manifolds of the fast dynamics, parameterized by the slow variables. In the other, the choice of our coarse variables automatically guarantees them to be 'slow' in a precise sense. This allows their evolution to be phrased in terms of averaging utilizing limit measures (probability distributions) of the fast flow. Coarse evolution equations are constructed based on these approaches and tested against coarse response of the 'microscopic' models. The second type of coarse variables are defined as (non-trivial) scalar state functions that are required by design to evolve autonomously, to the extent possible, with the goal of being candidate state functions for unambiguously initializable coarse dynamics. The question motivates a mathematical restatement in terms of a first-order PDE. A computational approximation is developed and tested on the Lorenz system and the Hald Hamiltonian system.

Tan, Likun; Acharya, Amit; Dayal, Kaushik

2013-01-01

160

Computer-aided Classification of Breast Masses: Performance and Interobserver Variability of Expert Radiologists versus Residents1  

PubMed Central

Purpose: To evaluate the interobserver variability in descriptions of breast masses by dedicated breast imagers and radiology residents and determine how any differences in lesion description affect the performance of a computer-aided diagnosis (CAD) computer classification system. Materials and Methods: Institutional review board approval was obtained for this HIPAA-compliant study, and the requirement to obtain informed consent was waived. Images of 50 breast lesions were individually interpreted by seven dedicated breast imagers and 10 radiology residents, yielding 850 lesion interpretations. Lesions were described with use of 11 descriptors from the Breast Imaging Reporting and Data System, and interobserver variability was calculated with the Cohen ? statistic. Those 11 features were selected, along with patient age, and merged together by a linear discriminant analysis (LDA) classification model trained by using 1005 previously existing cases. Variability in the recommendations of the computer model for different observers was also calculated with the Cohen ? statistic. Results: A significant difference was observed for six lesion features, and radiology residents had greater interobserver variability in their selection of five of the six features than did dedicated breast imagers. The LDA model accurately classified lesions for both sets of observers (area under the receiver operating characteristic curve = 0.94 for residents and 0.96 for dedicated imagers). Sensitivity was maintained at 100% for residents and improved from 98% to 100% for dedicated breast imagers. For residents, the computer model could potentially improve the specificity from 20% to 40% (P < .01) and the ? value from 0.09 to 0.53 (P < .001). For dedicated breast imagers, the computer model could increase the specificity from 34% to 43% (P = .16) and the ? value from 0.21 to 0.61 (P < .001). Conclusion: Among findings showing a significant difference, there was greater interobserver variability in lesion descriptions among residents; however, an LDA model using data from either dedicated breast imagers or residents yielded a consistently high performance in the differentiation of benign from malignant breast lesions, demonstrating potential for improving specificity and decreasing interobserver variability in biopsy recommendations. © RSNA, 2010

Maxwell, Jeff; Baker, Jay A.; Nicholas, Jennifer L.; Lo, Joseph Y.

2011-01-01

161

Daily atmospheric variability in the South American monsoon system  

NASA Astrophysics Data System (ADS)

The space-time structure of the daily atmospheric variability in the South American monsoon system has been studied using multichannel singular spectrum analysis of daily outgoing longwave radiation. The three leading eigenmodes are found to have low-frequency variability while four other modes form higher frequency oscillations. The first mode has the same time variability as that of El Nino-Southern Oscillation (ENSO) and exhibits strong correlation with the Pacific sea surface temperature (SST). The second mode varies on a decadal time scale with significant correlation with the Atlantic SST suggesting an association with the Atlantic multidecadal oscillation (AMO). The third mode also has decadal variability but shows an association with the SST of the Pacific decadal oscillation (PDO). The fourth and fifth modes describe an oscillation that has a period of about 165 days and is associated with the North Atlantic oscillation (NAO). The sixth and seventh modes describe an intraseasonal oscillation with a period of 52 days which shows strong relation with the Madden-Julian oscillation. There exists an important difference in the variability of convection between Amazon River Basin (ARB) and central-east South America (CESA). Both regions have similar variations due to ENSO though with higher magnitude in ARB. The AMO-related mode has almost identical variations in the two regions, whereas the PDO-related mode has opposite variations. The interseasonal NAO-related mode also has variations of opposite sign with comparable magnitudes in the two regions. The intraseasonal variability over the CESA is robust while it is very weak over the ARB region. The relative contributions from the low-frequency modes mainly determine the interannual variability of the seasonal mean monsoon although the interseasonal oscillation may contribute in a subtle way during certain years. The intraseasonal variability does not seem to influence the interannual variability in either region.

Krishnamurthy, V.; Misra, Vasubandhu

2011-08-01

162

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

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

163

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

PubMed Central

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

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

1991-01-01

164

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

165

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

NASA Astrophysics Data System (ADS)

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

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

2012-10-01

166

Factorial experimental designs elucidate significant variables affecting data acquisition on a quadrupole orbitrap mass spectrometer.  

PubMed

Instrument parameter values for a quadrupole Orbitrap mass spectrometer were optimized for performing global proteomic analyses. Fourteen factors were evaluated for their influence on data-dependent acquisition with an emphasis on both the rate of sequencing and spectral quality by maximizing two individually tested response variables (unique peptides and protein groups). Of the 14 factors, 12 factors were assigned significant contrast values (P?variables. Fundamentally, when optimizing parameters, a balance between spectral quality and duty cycle needs to be reached in order to maximize proteome coverage. This is especially true when using a data-dependent approach for sequencing complex proteomes. For example, maximum ion injection time, automatic gain control settings, and minimum threshold settings for triggering MS/MS isolation and activation all heavily influence ion signal, the number of spectra collected, and spectral quality. To better assess the effect these parameters have on data acquisition, all MS/MS data were parsed according to ion abundance by calculating the percent of the AGC target reached for each MS/MS event and then compared with successful peptide-spectrum matches. This proved to be an effective approach for understanding the effect of ion abundance on successful peptide-spectrum matches and establishing minimum ion abundance thresholds for triggering MS/MS isolation and activation. PMID:23913023

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

2013-08-03

167

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

2010-05-27

168

Parsing with logical variables (logic-based programming systems)  

SciTech Connect

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

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

1983-01-01

169

Research on multi-variable fuzzy predictive control based on integrated model of secondary system of the nuclear power plant  

Microsoft Academic Search

The mathematic models of once-through steam generator and turbine are built based on the mass, energy and momentum conservation theorem. Because of serious coupling and different dynamic characteristic, multi-variable fuzzy predictive control system is presented in order to improve the control characteristic of the nuclear power plant's secondary system, which is based on integrated model of the nuclear power plant's

Wei Zhang; Guoqing Xia; Jie Su; Zhiyun Cai; Hegao Cai

2010-01-01

170

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

171

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

172

How does variability of immune system genes affect placentation?  

Microsoft Academic Search

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

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

2011-01-01

173

Understanding the IDEA System's Extraneous Variables. IDEA Research Report.  

ERIC Educational Resources Information Center

Research has confirmed the common belief that instructional outcomes are influenced by "extraneous variables." It is important to separate the contributions of the teacher from the contributions of extraneous factors to student learning, and that is the purpose of the IDEA system's adjusted ratings. To adjust scores on the IDEA Center's Diagnostic…

Hoyt, Donald P.; Lee, Eun-Joo

174

Field Assessment of A Variable-rate Aerial Application System  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

175

Variable Rate Lime Application in Louisiana Sugarcane Production Systems  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

176

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

NASA Astrophysics Data System (ADS)

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

Groenewegen, M. A. T.

2004-10-01

177

Design of Mass Information Communication System Based on MCF52223  

Microsoft Academic Search

To mass data transmission and storage, a USB Mass Information Communication System, based on Freescale's 32-bit MCU - MCF52223, is designed in the paper. The MCF52223 integrates a USB module. The system can access document and data stored in U disk under the circumstance of no-PC. The system includes software part and hardware part. The software part based on the

Dejun Meng; Zhigui Lin; Qingqing Zhong

2011-01-01

178

Maximum Power Transmission in Mass-Limited Radio Systems  

Microsoft Academic Search

A simple fundamental relationship is derived between antenna gain and transmitter power which maximizes the effective radiated power in mass-limited satellite systems. In the most common case, maximum effective radiated power is achieved when the payload mass is divided equally between the antenna system and the power system. Although this may have been known intuitively to satellite designers, to the

D. Reudink

1982-01-01

179

Maximum power transmission in mass-limited radio systems  

Microsoft Academic Search

A simple fundamental relationship is derived between antenna gain and transmitter power which maximizes the effective radiated power in mass-limited satellite systems. In the most common case, maximum effective radiated power is achieved when the payload mass is divided equally between the antenna system and the power system. Example calculations show that considerable increases in performance can be expected for

D. O. Reudink

1982-01-01

180

Groundwater mass transport and equilibrium chemistry model for multicomponent systems  

Microsoft Academic Search

A mass-transport model, TRANQL, for a multicomponent solution system was developed. The equilibrium interaction chemistry is posed independently of the mass-transport equations which leads to a set of algebraic equations for the chemistry coupled to a set of differential equations for the mass transport. Significant equilibrium chemical reactions such as complexation, ion exchange, competitive adsorption, and dissociation of water may

Gail A. Cederberg; James O. Leckie

1985-01-01

181

A control system design method for a system having a plant with variable parameters  

Microsoft Academic Search

A design method is presented which permits a feedback control system with variable plant parameters to satisfy the desired performance specifications. The method utilizes state-variable feedback with constant feedback gains and satisfies the quadratic performance index (P.I.). The design application is an aircraft pitch attitude control system. The control system must be insensitive to parameter variations which occur over a

C. H. HOUPIS

1975-01-01

182

Luminous Blue Variables and Related High Mass Evolved Stars in M31 and Their Surprising Environments  

NASA Astrophysics Data System (ADS)

Luminous Blue Variables (LBVs) are erratically eruptive massive stars near the Eddington limit thought to be descendants of blue supergiants and progenitors of Wolf-Rayet stars. In order to constrain the evolution of these massive stars we would like to know their bolometric luminosities, effective temperatures, current masses, progenitor masses, ages, and abundances. With the use of 3.5-m class telescopes (WIYN and ARC) we are able to constrain all but the abundances for these LBV-type stars in M31. We began the study by developing a method for identifying candidate LBVs through deep narrow-band images. A target list was drawn for the NE half of M31. We obtained follow-up spectroscopy that confirmed the success of our search criteria. The spectra provided mass-loss rates for the objects with P-Cygni type profiles and spectral-type constraints from the presence of high or low excitation lines. With WIYN images we measured color-magnitude diagrams for the resolved luminous stars and we charted the locations of HII regions and HI holes as indicators of stellar ages in the areas around our program stars. Surprisingly the majority of the LBV-type objects were found to be in or near associations older than the LBV-type objects themselves. The age discrepancies between LBV and environment might be explained if the LBVs or candidate LBVs are runaways, are products of discrete massive star forming events, have lived longer than theoretically expected, or are exotic binaries such as Thorne-Zytkow or mass-transferring close binaries. We note that with the development of the wind-momentum-luminosity relation (WMLR) by Kudritzki et al. LBVs may one day be secondary distance indicators. We find that M31 LBV V15 is located in the same place of the WMLR diagram as Galactic and LMC LBVs and we hope to investigate this for a few more stars. [Support for thesis provided by NM Space Grant Consortium and NSF grant AST96-17014.

King, N. L.

1999-12-01

183

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

184

Nonequilibrium Thermodynamics of Stochastic Systems with Odd and Even Variables  

NASA Astrophysics Data System (ADS)

The total entropy production of stochastic systems can be divided into three quantities. The first corresponds to the excess heat, while the second two comprise the housekeeping heat. We denote these two components the transient and generalized housekeeping heat and we obtain an integral fluctuation theorem for the latter, valid for all Markovian stochastic dynamics. A previously reported formalism is obtained when the stationary probability distribution is symmetric for all variables that are odd under time reversal, which restricts consideration of directional variables such as velocity.

Spinney, Richard E.; Ford, Ian J.

2012-04-01

185

Nonequilibrium entropy, Lyapounov variables, and ergodic properties of classical systems  

PubMed Central

We discuss the problem of defining (nonequilibrium) entropy in terms of the concepts of mechanics and of reconciling its monotonic increase with the Hamiltonian evolution of the dynamical system. This leads to investigating necessary and sufficient conditions for the existence of monotonically increasing quantities or the so-called Lyapounov variables of classical systems. It is found that the condition of “mixing” is necessary and the property of being K-flow is sufficient for the existence of a Lyapounov variable. The significance of the study of Lyapounov variables for the elucidation of the fundamental questions of statistical mechanics is briefly discussed. It is seen that every Lyapounov variable must fail to commute with at least some of the operators of multiplication by phase space functions. The uncertainty relations implied by this necessary noncommutativity would then set a limit on the simultaneous determination of entropy and trajectories in phase space. These considerations thus support and sharpen the view that the thermodynamical and the (microscopic) dynamical descriptions of classical systems could be consistently reconciled as being complementary descriptions analogous to the complementary descriptions encountered in quantum mechanics.

Misra, B.

1978-01-01

186

Development and characterization of a variable turbulence generation system  

NASA Astrophysics Data System (ADS)

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

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

2011-09-01

187

Sound reproduction systems using variable-directivity loudspeakers.  

PubMed

Sound reproduction systems using omnidirectional loudspeakers produce reflections from room surfaces which interfere with the desired sound field within the array. While active compensation systems can reduce the reverberant level, they require calibration in each room and are processor-intensive. Directional loudspeakers allow the direct to reverberant level to be improved within the array, but still produce a finite exterior field which reflects from the room surfaces. The use of variable-directivity loudspeakers allows the exterior field to be eliminated at low frequencies by implementing the Kirchhoff-Helmholtz integral equation. This paper investigates the performance of variable-directivity arrays in reducing reverberant levels and compares the results with those derived in a previous paper for fixed-directivity arrays. The results presented may have some impact on the design of commercial multi-channel systems for sound reproduction. PMID:21428507

Poletti, M A; Fazi, F M; Nelson, P A

2011-03-01

188

Measuring the Mass Ratios of X-Ray Transients and Cataclysmic Variables from Rotational Broadening  

NASA Astrophysics Data System (ADS)

Soft X-ray transients (SXTs) are interacting binary stars in which a compact star is stripping mass from a relatively normal companion star (the ``secondary'' star). One step in the usual method for measuring the mass of the compact star in these systems is to determine the mass ratio from the rotational broadening of the absorption lines in the spectrum of the secondary. With a few outstanding exceptions (e.g., Shahbaz 2003), the observations have typically been analyzed assuming that the observed spectrum is the convolution of the spectrum of a non-rotating star with a line-broadening kernel appropriate for a rotating, spherical star. The results are often inadequate because 1) the widths of the absorption lines vary with orbital phase by 10 % or more because the secondary is not spherical, 2) the line broadening differs from line to line because the limb darkening differs from line to line, and 3) the shapes of the line profiles vary strongly with orbital phase because the secondary is not symmetric even in projection. We describe a new program for calculating the spectra of stars that fill their Roche lobes in close binary stars. The program calculates the observed spectrum by summing wavelength-dependent specific intensities over the visible surface of the distorted, lobe-filling star.

Bitner, M. A.; Robinson, E. L.

2003-12-01

189

The Research about the Derivation and the Applicability of the Aircraft Four Control Variables Point Mass Model  

NASA Astrophysics Data System (ADS)

A new point mass model of the air vehicle has been developed in our laboratory. This model employs angle-of-attack, side slip angle, bank angle and thrust, as four control variables. The existent three control variables point mass model cannot introduce the winds and active side slip angle control, while this new model can introduce them. This paper explains about the model at first. The model is applied to the YF-16 aircraft and simulations are conducted for two maneuvers as typical examples, which show the effectiveness and the preciseness of this model.

Imado, Fumiaki; Heike, Yuki; Kinoshita, Takuya

190

Oscillations and variability in the p53 system  

PubMed Central

Understanding the dynamics and variability of protein circuitry requires accurate measurements in living cells as well as theoretical models. To address this, we employed one of the best-studied protein circuits in human cells, the negative feedback loop between the tumor suppressor p53 and the oncogene Mdm2. We measured the dynamics of fluorescently tagged p53 and Mdm2 over several days in individual living cells. We found that isogenic cells in the same environment behaved in highly variable ways following DNA-damaging gamma irradiation: some cells showed undamped oscillations for at least 3 days (more than 10 peaks). The amplitude of the oscillations was much more variable than the period. Sister cells continued to oscillate in a correlated way after cell division, but lost correlation after about 11 h on average. Other cells showed low-frequency fluctuations that did not resemble oscillations. We also analyzed different families of mathematical models of the system, including a novel checkpoint mechanism. The models point to the possible source of the variability in the oscillations: low-frequency noise in protein production rates, rather than noise in other parameters such as degradation rates. This study provides a view of the extensive variability of the behavior of a protein circuit in living human cells, both from cell to cell and in the same cell over time.

Geva-Zatorsky, Naama; Rosenfeld, Nitzan; Itzkovitz, Shalev; Milo, Ron; Sigal, Alex; Dekel, Erez; Yarnitzky, Talia; Liron, Yuvalal; Polak, Paz; Lahav, Galit; Alon, Uri

2006-01-01

191

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

Microsoft Academic Search

A 41-year-long reconstructed annual mean glacier mass balance record from the Cordillera Blanca, Peru, was investigated for its climate sensitivity toward temperature, humidity and precipitation, and its links with the large-scale atmospheric circulation. On interannual timescales precipitation variability appears to be the main driver for glacier mass balance fluctuations in the Cordillera Blanca. This is corroborated by an analysis of

Mathias Vuille; Georg Kaser; Irmgard Juen

2008-01-01

192

Earth System Science Education Centered on Natural Climate Variability  

NASA Astrophysics Data System (ADS)

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

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

2009-12-01

193

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

SciTech Connect

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

Das, Mini; Gifford, Howard C.; O'Connor, J. Michael; Glick, Stephen J. [Department of Radiology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, Massachusetts 01655 (United States)

2009-06-15

194

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

195

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

196

Revision of the relativistic dynamics with variable rest mass and application to relativistic thermodynamics  

Microsoft Academic Search

Summary  For point bodies with variable rest mass it is shown that the definition of forcem\\u000a 0dU\\u000a i\\u000a \\/d?=F\\u000a i is better than the usual d(m\\u000a 0\\u000a U\\u000a i))\\/d?=F\\u000a i and the explicit equation of motion is given bym\\u000a 0dU\\u000a i\\/d?=F\\u000a \\u000a \\u000a i\\u000a \\u000a ext\\u000a +(z\\u000a ?1\\u000a U\\u000a \\u000a i\\u000a B\\u000a ?U\\u000a i)dm\\u000a 0\\/d?, where the external forceF\\u000a \\u000a \\u000a i\\u000a \\u000a ext\\u000a has been separated from

G. Cavalleri; G. Salgarelli

1969-01-01

197

A Monte Carlo Method to Find Mass Flux Variability in the North Atlantic and Southern Oceans  

NASA Astrophysics Data System (ADS)

Using the concept of transit-time distributions (TTDs), we estimate the volume transports and spreading rates of Labrador Sea Water (LSW), Antarctic Intermediate Water (AAIW), and North Atlantic Deep Water (NADW) through different repeat hydrographic-sections of the ocean with observations of transient tracers and model output from the National Center for Atmospheric Research (NCAR) high resolution Parallel Ocean Program (POP) model. We estimate the TTDs using inverse Gaussians (IGs) that are observationally informed from pCFC and statistically estimated Helium-3/Tritium ages. The Helium-3/Tritium ages are estimated using a nonparametric statistical model that works well with sparse observations and quantifies uncertainty associated with mapping. In areas where water masses of vastly different ages mix, this representation is extended to a mixture of two IGs. Using the NCAR POP model TTDs as priors, we arrive at a Bayesian estimate of a multiple peaked TTD and estimate the mean ages and Peclet number at each location and depth. We find that once a mean age of about 50 years is surpassed, statistically estimated Helium-3/Tritium serves to add more information than CFCs would have alone, but the uncertainties on the IG parameters below the thermocline can often be large enough to not be able to distinguish the Peclet number from zero. We also find smaller average spreading rates than those inferred from previous studies with intra-annual variability larger for NADW than AAIW and LSW with the smallest, assuming steady-state for each snapshot.

Trossman, D. S.; Thompson, L.; Bryan, F. O.; Mecking, S.; Warner, M. J.; Peacock, S.

2010-12-01

198

Automated, differentially pumped, mass-spectrometer sampling system  

Microsoft Academic Search

The design, construction, and testing of an automated gas sampling system for a quadrupole mass spectrometer on a process chamber with a wide pressure range is described. A set of two parallel stepper-activated vacuum valves are used to vary the amount of gas admitted into the mass spectrometer chamber. The computer-controlled sampling system automatically adjusts the position of the valves

Jon C. Little; Lloyd B. Gordon

1991-01-01

199

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

200

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

201

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

202

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

SciTech Connect

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

Kniehl, B. A.; Kramer, G. [II. Institut fuer Theoretische Physik, Universitaet Hamburg, Luruper Chaussee 149, D-22761 Hamburg (Germany); Schienbein, I. [Laboratoire de Physique Subatomique et de Cosmologie, Universite Joseph Fourier Grenoble 1, CNRS/IN2P3, Institut National Polytechnique de Grenoble, 53 avenue des Martyrs, F-38026 Grenoble (France); Spiesberger, H. [Institut fuer Physik, Johannes-Gutenberg-Universitaet, Staudinger Weg 7, D-55099 Mainz (Germany)

2011-11-01

203

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

204

Time-variable aliasing effects of ocean tides, atmosphere, and continental water mass on monthly mean GRACE gravity field  

Microsoft Academic Search

The Gravity Recovery and Climate Experiment (GRACE) satellite mission will provide new measurements of Earth's static and time-variable gravity fields with monthly resolution. The temporal effects due to ocean tides and atmospheric mass redistribution are assumed known and could be removed using current models. In this study we quantify the aliasing effects on monthly mean GRACE gravity estimates due to

Shin-Chan Han; Christopher Jekeli; C. K. Shum

2004-01-01

205

PORFLO-3: A mathematical model for fluid flow, heat, and mass transport in variably saturated geologic media  

Microsoft Academic Search

This manual provides instructions for the use of the PORFLO-3 computer code. This computer code is based on mathematical formulation of fluid flow, heat transfer, and mass transport in variably saturated geologic media. The geologic medium may be heterogeneous and anisotropic and may contain linear and planar features such as boreholes and fractures. The code can be used to analyze

A. K. Runchal; B. Sagar; N. W. Kline

1992-01-01

206

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

207

Ethambutol Pharmacokinetic Variability Is Linked to Body Mass in Overweight, Obese, and Extremely Obese People  

PubMed Central

We conducted a prospective study of 18 adult volunteers (male-to-female ratio of 1) whose body mass index fell into categories of <25, 25 to 40, or >40 kg/m2, who received a single oral dose of 1,600 mg ethambutol. Only individuals with normal renal function were recruited. The minimum body mass (M) was 45.6 kg, the median was 90.8 kg, and the maximum weight was 160.4 kg. Ethambutol pharmacokinetics were best described by a two-compartment model. Inclusion of weight as a covariate dramatically improved the model, with a relative likelihood approaching infinity. The typical clearance was 42.6 liters/h. Ethambutol systemic clearance was proportional to (M/45.6)3/4 and thus obeyed fractal geometry-based laws. This means that the area under the concentration-time curve (AUC) actually decreased for obese patients compared to that for leaner patients, reducing chances of concentration-dependent toxicity. On the other hand, such reduced AUCs could lead to therapy failure. Thus, new and individualized ethambutol dosing regimens need to be designed for obese and extremely obese patients.

Swancutt, Mark A.; Meek, Claudia; Leff, Richard D.; Gumbo, Tawanda

2012-01-01

208

Measuring the mass of solar system planets using pulsar timing  

NASA Astrophysics Data System (ADS)

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)×10-4Msolar, 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.; Backer, D. C.; Bailes, M.; Bhat, N. D. R.; Burke-Spolaor, S.; Coles, W.; Demorest, P. B.; Ferdman, R. D.; Folkner, W. M.; Hotan, A. W.; Kramer, M.; Lommen, A. N.; Nice, D. J.; Purver, M. B.; Sarkissian, J. M.; Stairs, I. H.; van Straten, W.; Verbiest, J. P. W.; Yardley, D. R. B.

2011-08-01

209

Minimal Functional ?-Cell Mass in Intraportal Implants That Reduces Glycemic Variability in Type 1 Diabetic Recipients.  

PubMed

OBJECTIVE Previous work has shown a correlation between ?-cell number in cultured islet cell grafts and their ability to induce C-peptide secretion after intraportal implantation in C-peptide-negative type1 diabetic patients. In this cross-sectional study, we examined the minimal functional ?-cell mass (FBM) in the implant that induces metabolic improvement. RESEARCH DESIGN AND METHODS Glucose clamps assessed FBM in 42 recipients with established implants. C-peptide release during each phase was expressed as percentage of healthy control values. Its relative magnitude during a second hyperglycemic phase was most discriminative and therefore selected as a parameter to be correlated with metabolic effects. RESULTS Recipients with functioning ?-cell implants exhibited average FBM corresponding to 18% of that in normal control subjects (interquartile range 10-33%). Its relative magnitude negatively correlated with HbA1c levels (r = -0.47), daily insulin dose (r = -0.75), and coefficient of variation of fasting glycemia (CVfg) (r = -0.78, retained in multivariate analysis). A correlation between FBM and CVfg <25% appeared from the receiver operating characteristic curve (0.97 [95% CI 0.93-1.00]). All patients with FBM >37% exhibited CVfg <25% and a >50% reduction of their pretransplant CVfg; this occurred in none with FBM <5%. Implants with FBM >18% reduced CVfg from a median pretransplant value of 46 to <25%. CONCLUSIONS Glucose clamping assesses the degree of restoration in FBM achieved by islet cell implants. Values >37% of normal control subjects appear needed to reduce glycemic variability in type 1 diabetic recipients. Further studies should examine whether the test can help guide decisions on additional islet cell transplants and on adjusting or stopping immunotherapy. PMID:24041683

Gillard, Pieter; Hilbrands, Robert; Van de Velde, Ursule; Ling, Zhidong; Lee, Da Hae; Weets, Ilse; Gorus, Frans; De Block, Christophe; Kaufman, Leonard; Mathieu, Chantal; Pipeleers, Daniel; Keymeulen, Bart

2013-09-16

210

NASA LANGLEY RESEARCH CENTER'S DISTRIBUTED MASS STORAGE SYSTEM  

Microsoft Academic Search

Abstract 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 the NASA Langley Research Center (LaRC) is building such a system and expects to put it into production use by the end of 1993. This paper

Juliet Z. Pao; D. Creig Humes

211

Open loop compensation in a stack-mass positioning system  

NASA Astrophysics Data System (ADS)

A piezoceramic stack-mass positioning system was tested with different frequencies and voltages for its response to different input conditions. It is observed that the response of the positioning system varied with different input conditions. A technique is developed to compensate for this variation by the use of an open loop compensator. This open loop controller is able to compensate for the phase lag inherent in the stack-mass system, thereby improving its dynamic response and position resolution.

Duong, Khanh; Garcia, Ephrahim

1995-03-01

212

Automated, differentially pumped, mass-spectrometer sampling system  

NASA Astrophysics Data System (ADS)

The design, construction, and testing of an automated gas sampling system for a quadrupole mass spectrometer on a process chamber with a wide pressure range is described. A set of two parallel stepper-activated vacuum valves are used to vary the amount of gas admitted into the mass spectrometer chamber. The computer-controlled sampling system automatically adjusts the position of the valves to provide the proper leak rate so that the mass spectrometer can continuously monitor a process chamber with a time varying pressure between 760 and 0.00002 torr. This provides a constant pressure at the mass spectrometer sensing head, despite the varying process chamber pressure. No commercially-available mass spectrometer system was found which was able to automatically monitor the gas composition in a proces chamber with such time varying pressures. The principles of operation are presented along with calculations of the gas flow and the control equations.

Little, Jon C.; Gordon, Lloyd B.

1991-02-01

213

Weighting systems for linear functions of correlated variables when there is no dependent variable  

Microsoft Academic Search

When no criterion variable is available, the combination of tests or other variables by the use of multiple correlation is not possible. Three methods of combining variables are described mathematically, and discussed with reference to the linear combination of tests. Iterative computational schemes are outlined and illustrated.

S. S. Wilks

1938-01-01

214

Implications of mass customisation on business information systems  

Microsoft Academic Search

Modern information and communication technologies like the internet or mobile computing are enforcing changes of Business Information Systems (BIS) in the context of an evolving e-business and global economy. This paper analyses the impact of mass customisation on future BIS, with focus on globally distributed value chains. Consequently, we address the question of how to scale mass customisation in existing

Andreas J. Dietrich; Stefan Kirn; Ingo J. Timm

2006-01-01

215

Automated, differentially pumped, mass-spectrometer sampling system  

Microsoft Academic Search

The design, construction, and testing of an automated gas sampling system for a quadrupole mass spectrometer on a process chamber with a wide pressure range is described. A set of two parallel stepper-activated vacuum valves are used to vary the amount of gas admitted into the mass spectrometer chamber. One valve is a standard low-conductance leak valve to allow the

Jon C. Little; Lloyd B. Gordon

1991-01-01

216

Variations of Orbital Elements in Binary Systems with Mass Transfer  

Microsoft Academic Search

General formulae are derived giving the infinitesimal variations in orbital elements in a binary system with mass exchange. These variations are discussed in two Sections of the paper. In the first, we deal with instantaneous variations in the orbital elements and spin of a star resulting from ejection or landing with arbitrary relative velocity of an infinitesimal mass particle. In

S. L. Piotrowski

1964-01-01

217

Entanglement criteria and nonlocality for multimode continuous-variable systems  

NASA Astrophysics Data System (ADS)

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

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

2009-08-01

218

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

PubMed

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 km(3)/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 km(3)/y(2), which was largely attributed to an increase of global-ocean evaporation (768 km(3)/y(2)). Sustained growth of these flux rates into long-term trends would provide evidence for increasing intensity of the hydrologic cycle. PMID:20921364

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

2010-10-04

219

Energy harvesting in the nonlinear two-masses piezoelastic system driven by harmonic excitations  

NASA Astrophysics Data System (ADS)

We examine the energy harvesting system consisted of two different masses (magnets) attached to piezoelastic oscillators, coupled by the electric circuit, and driven by harmonic excitations. The nonlinearity of the system is achieved by variable distance between vibrating magnetic masses and the magnets attached directly to the harvester. We also introduce the mistuning parameter which describes the disproportion of vibrating masses (their ratio). In our work we examine the dependence of output power (in terms of mean squared voltage) generated on electric load on excitation frequencies for different values of mistuning parameter and additionally for different values of system nonlinearity parameter. We compare obtained results with the dia- grams presenting relative displacements of these oscillators (in terms of standard deviation) vs. excitation frequencies. In the second part of this paper we present the phase boundary lines (phase portraits) for selected values of applied frequency to show the complicated behavior of the oscillators in the nonlinear regime when the mistuning appears.

Kucab, K.; Górski, G.; Mizia, J.

2013-09-01

220

Contaminant plume classification system based on mass discharge.  

PubMed

Estimation of mass discharge has become an increasingly valuable analysis technique at sites with contaminated groundwater plumes. We propose a simple plume magnitude classification system based on mass discharge comprised of 10 separate magnitude categories, such as a "Mag 7 plume." This system can be a useful tool for scientists, engineers, regulators, and stakeholders to better communicate site conceptual models, prioritize sites, evaluate plumes both spatially and temporally, and determine potential impacts. PMID:21306359

Newell, Charles J; Farhat, Shahla K; Adamson, David T; Looney, Brian B

2011-02-09

221

Acquisition of a Liquid Chromatography/Mass-Spectrometry System.  

National Technical Information Service (NTIS)

An LC/MS system consisting of the Finnigan LCQ ion-trap mass- spectrometer and a Shimadzu HPLC system was purchased. The system was installed successfully and has been operational since September 1997. We have developed a number of LC/MS methods for the a...

R. Goericke

1998-01-01

222

Control of seismic-excited buildings using active variable stiffness systems  

Microsoft Academic Search

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

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

1996-01-01

223

Genetic optimization algorithm on PID decoupling controller for variable flow heating system  

Microsoft Academic Search

Heating systems are used in homes and apartments worldwide. The variable flow system is advantaged to the energy saving while the control in variable flow system is difficult. This paper describes the typical variable flow heating system and presents the coupling mathematical model of heat exchanger. Based on the mathematical model, a new multivariable PID decoupling controller is proposed. This

Jiangjiang Wang; Youyin Jing; Chunfa Zhang

2008-01-01

224

Variable structure multiple model tracking for airborne laser communication systems  

NASA Astrophysics Data System (ADS)

Free space laser communication based on airborne platforms will play a important role on the future space communications, high precision tracking system for airborne laser communication has been already the one of the best difficult problem. Because of diversity of maneuvering forms and high nonlinear problem, it is usual to adopt multiple models algorithm with a fixed structure for tracking system, which brings unnecessary inter-competition among the amount of models and calculation burden, in order to resolve this contradiction, a variable structure multiple-model (VSMM)based on digraph switching is presented, the particle filter (PF) can deal with nonlinear/non-Guassian problems, it can be introduced into VSMM framework. Simulation results show that the algorithm improves the accuracy of tracking by reducing the competition of the models as well as reducing the computation burden.

Cao, Yang; Guo, Jing; Huang, Liwen

2013-08-01

225

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

226

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

227

[Mass flow anesthesia delivery system and its application].  

PubMed

Microcomputer-based anesthesia delivery system using mass flow control devices has been developed. System is superior in computer control to conventional anesthesia machine because there is no mechanical setting. System consists of three thermal mass flow controllers (TMFC), one vapor source controller (VSC), personal computer system, and air circuits. Personal computer system has facilities of digital output, analogue input and analogue output interfaces. TMFCs and VSC are devices which operational principle is based on the thermal conductance and they are controlled by electrical signals from computer in the system. TMFCs control the mass flow of nitrous oxide, oxygen and carbon oxide according to each input voltage signal. VSC regulates mass vapor of halothane in order to keep set value up by means of alteration of oxygen carrier gas flow. Computer always monitors the gas flow of the TMFCs and VSC so that computer compensates the change of the carrier gas flow of VSC by regulating the TMFC for oxygen. Mixed gas from TMFCs and VSC is supplied through the air circuit to subject. Characteristics of the system was measured by mass spectrometer and flowmeter. Stability was 0.05% change after 30 minutes at the initial set of 3%. Experiment on animals using mongrel dogs has been performed to verify the system functions. PMID:2754861

Takahashi, M; Ishida, A; Toyooka, H; Amaha, K

1989-03-01

228

Mass Measurement System Using Relay Feedback with Hysteresis  

NASA Astrophysics Data System (ADS)

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

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

229

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

230

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

231

Intake of sweet foods and counts of cariogenic microorganisms in relation to body mass index and psychometric variables in women  

Microsoft Academic Search

OBJECTIVE: As a part of the SPAWN (Stockholm Pregnancy and Women's Nutrition) study, the intake of sweet foods (habitual and pre-menstrual intakes) and the number of cariogenic microorganisms in saliva was analysed in relation to body mass index (BMI) and psychometric variables.DESIGN: A cross-sectional study.SUBJECTS: Three hundred and sixty-two women with a median BMI of 24.2 kg\\/m2 (range 17.5–47.8) and

B Barkeling; Y Linné; AK Lindroos; D Birkhed; P Rooth; S Rössner

2002-01-01

232

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

Microsoft Academic Search

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

Achim Feldmeier; Isaac Shlosman; Peter Vitello

1999-01-01

233

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

234

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

235

Analyses of gas composition in vacuum systems by mass spectrometry.  

PubMed

Analyses of the composition of residual gases for diagnostic purposes, analyses of the atmosphere enforced by the introduction of gases for technological purposes and analyses of gases released from analyte materials in numerous analytical methods (e.g. TSD, SIMS) are frequently carried out in vacuum systems. There is only a small amount of gas available, in the vacuum system so the most important property of a mass spectrometer is high sensitivity. As a consequence, the mass resolution is usually low. Moreover, a low outgassing rate of the mass spectrometer itself and all parts connecting it to the vacuum system is required. Dynamic mass spectrometry satisfies these demands best. Quadrupole mass spectrometers are almost solely utilized in applications, although the time-of-flight mass spectrometer has come into use recently. The main disadvantage of the quadrupole mass spectrometer is a strong dependence of the sensitivity and the mass discrimination factor on the stability of the supply voltages. Together with the necessity to use multipliers for detection of the ion current, this leads to a requirement for frequent recalibration. Another serious problem, that is met in such applications is the estimation of the gas composition from the measured mass spectra. Usually, the analyte gas mixtures consist of various individual gases, or at least are measured on a background of such mixtures. This implies a requirement for the exact knowledge of the fragmentation pattern of the gases, and again the necessity for frequent calibration over a satisfactorily wide range of mass numbers. Some theoretical considerations and some experimental results obtained by the authors are presented. PMID:12489090

Repa, P; Tesar, J; Gronych, T; Peksa, L; Wild, J

2002-12-01

236

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

237

Tropical Pacific Variability in the NCAR Climate System Model.  

NASA Astrophysics Data System (ADS)

A 300-yr simulation with the NCAR Climate System Model (CSM), version 1, captured only 60% of the observed ENSO signal and exaggerated the interannual variability of SST in the western tropical Pacific. Here, a simulation with a new version of the CSM, which significantly improves the spatial and temporal patterns of tropical Pacific variability, is described. Maximum SST variability is shifted to the central and eastern Pacific. A better simulation of the equatorial Pacific thermocline structure results in Niño-3 and Niño-4 statistics comparable to the observed estimates for the last century. The evolution of SST and subsurface temperature anomalies is in excellent agreement with observed events. The majority of events evolve as a standing mode with weak SST anomalies occurring in the northern spring in the eastern tropical Pacific and maximum anomalies covering the eastern tropical Pacific Ocean to the date line by the following northern winter. At the same time, subsurface temperature anomalies spread eastward and upward along the tropical thermocline. The `delayed oscillator' and Wyrtki's `buildup' hypothesis are consistent with aspects of the CSM simulation. On the equator, a westerly wind stress anomaly in the central Pacific forces off-equatorial upwelling anomalies, which propagate westward, reaching the western boundary about one-half year later. This upwelling signal then propagates eastward along the equator, arriving 2 months before cooling in the eastern Pacific basin. The tropical Pacific atmospheric response to warm oceanic events also agrees with observational analyses with a negative Southern Oscillation pattern in sea level pressure, wind stress anomalies, and low-level convergence to the west of the maximum SST anomalies and enhanced deep convection and precipitation in the central and eastern tropical Pacific.

Otto-Bliesner, Bette L.; Brady, Esther C.

2001-09-01

238

Observer Variability of the Breast Imaging Reporting and Data System (BI-RADS) Lexicon for Mammography  

PubMed Central

Aim We aimed to determine the inter- and intra-observer variabilities between breast radiologists and a general radiologist in categorizing mammographic lesions using the Breast Imaging Reporting and Data System (BI-RADS), and to evaluate the effects of the histopathologic results on the variability. Methods Mammograms from 142 women who underwent biopsy were evaluated. 3 breast radiologists (2 with >10 years experience and 1 with 1 year experience) and 1 general radiologist retrospectively reviewed mammograms twice within an 8-week interval. Inter- and intra-observer variabilities were assessed with Cohen's kappa statistic, and the positive predictive value for final assessments was calculated. Results The intra-observer variability for mass and calcification assessments was moderate to almost perfect (kappa values: 0.41–1) for breast imagers and was fair to substantial for the general radiologist (kappa values: 0.21–0.8). Inter-observer agreement between the breast imagers was higher than between the breast and general radiologists. There was no apparent difference in agreement between observers for malignant and benign subgroups. Conclusions The differences in intra- and inter-observer agreement between the breast imagers and the general radiologist affirm the utility of the BI-RADS lexicon. The histopathologic results of the lesions do not affect the agreement. BI-RADS is a simple and adequate tool for assessing mammograms, even after only 1 year of training.

Adibelli, Zehra H.; Ergenc, Ruken; Oztekin, Ozgur; Ecevit, Suheyla; Unal, Gokhan; Abal?, Yusuf

2010-01-01

239

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

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

240

Mass change, environmental variability and female fertility in wild Propithecus verreauxi.  

PubMed

Accurate estimates of mass and size are important in a wide range of research questions in population and evolutionary biology, and yet such data are still rare for wild primates. This study presents detailed longitudinal data from a large population of wild indriids, and demonstrates links between fluctuations in body mass, environmental cycles, and reproduction. Understanding these links is a necessary step toward explaining the function and evolution of distinctive features of lemur biology and behavior. During the first 12 years of an ongoing study of the sifaka, Propithecus verreauxi verreauxi, at Beza Mahafaly in southwest Madagascar, 320 animals were captured and weighed throughout the year. Adult males and females exhibit seasonal cycles of mass loss, with females losing significantly more mass than males. In 2 drought years this pattern was especially pronounced. Compared to lighter females, females who were heavier at the time of the mating season were more likely to give birth in the following birth season. By showing (1) seasonally greater mass loss in reproductive females compared to males, particularly in drought years, (2) a close link between female mass and fertility, and (3) an uncoupling of the periods of highest body mass and of gestation and lactation, these results suggest that energy acquisition and storage are critically important in the life history strategies of female sifaka, and that "capital breeding" may be a feature of sifaka reproductive strategies. PMID:11006047

Richard, A F; Dewar, R E; Schwartz, M; Ratsirarson, J

2000-10-01

241

On the nature of the variability of the Martian thermospheric mass density: Results from electron reflectometry with Mars Global Surveyor  

NASA Astrophysics Data System (ADS)

Knowledge of Mars' thermospheric mass density is important for understanding the current state and evolution of the Martian atmosphere, and for spacecraft such as the upcoming MAVEN mission that will fly through this region on every orbit. Global-scale atmospheric models have been shown thus far to do an inconsistent job of matching the mass density observations at these altitudes, especially on the nightside. Thus, there is a clear need for a data-driven estimate of the mass density in this region. Given the wide range of conditions and locations over which this must be defined, the data set of thermospheric mass densities derived from energy and angular distributions of super-thermal electrons measured by the MAG/ER experiment on Mars Global Surveyor, spanning 4 full Martian years, is an extremely valuable resource. Here we present an empirical model of the thermospheric density structure of this data set. Using this new model, we assess the global-scale response of the thermosphere to dust storms in the lower atmosphere and show that this varies with both latitude and dust opacity. Further, we examine the short-term variability of the thermospheric density and show that it exhibits a repeatable behavior with latitude and season that is indicative of atmospheric wave activity seen in the lower thermosphere. This short-term variability is consistently highest in the southern hemisphere, peaking around perihelion, which may have significant implications for studies of atmospheric escape.

England, Scott L.; Lillis, Robert J.

2012-02-01

242

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

243

Validation of a body condition scoring system in rhesus macaques (Macaca mulatta): inter- and intrarater variability.  

PubMed

Body condition scoring (BCS) is a subjective semiquantitative method of assessing body fat and muscle. Scoring systems use a scale in which the midrange represents optimal body condition, lower values represent lean to emaciated conditions, and higher values indicate excessive body fat. A valid BCS system is clearly described, relevant to the species, shows agreement within and between raters, and is consistent with objective measures. The goal of the current study was to assess intra- and interrater variability of a BCS system that uses a 1-to-5 scale and entails the palpation of key anatomic sites (hips, spine, pelvis, thorax, and abdomen) to assess prominence of bony structures, muscle mass, and subcutaneous fat. To assess interrater variability, 4 raters independently assessed BCS in 616 rhesus macaques (Macaca mulatta) in 4 age groups: infant, younger than 1 y; juvenile, 1 to 4 y; subadult, 4 to 7 y; and adult, 7 to 17 y. To assess intrarater variability, each rater independently reevaluated a subset of adult macaques (n = 15) within 2 wk of initial evaluation. A weighted ? score was used to analyze intra- and interrater variability. Agreement between raters was highest for subadult and adult macaques, intermediate for juveniles, and least for infants. Intrarater agreement was high for all raters except one, for which it was moderate. Our results suggest that raters applied the BCS system most consistently to adult and subadult macaques and less so to juvenile and infant animals. However, the percentage agreement between raters to within one half of a score unit increased markedly when raters scored infants in the context of 'as is' rather than 'ideal for age.' PMID:22330865

Clingerman, Karen J; Summers, Laura

2012-01-01

244

Validation of a Body Condition Scoring System in Rhesus Macaques (Macaca mulatta): Inter- and Intrarater Variability  

PubMed Central

Body condition scoring (BCS) is a subjective semiquantitative method of assessing body fat and muscle. Scoring systems use a scale in which the midrange represents optimal body condition, lower values represent lean to emaciated conditions, and higher values indicate excessive body fat. A valid BCS system is clearly described, relevant to the species, shows agreement within and between raters, and is consistent with objective measures. The goal of the current study was to assess intra- and interrater variability of a BCS system that uses a 1-to-5 scale and entails the palpation of key anatomic sites (hips, spine, pelvis, thorax, and abdomen) to assess prominence of bony structures, muscle mass, and subcutaneous fat. To assess interrater variability, 4 raters independently assessed BCS in 616 rhesus macaques (Macaca mulatta) in 4 age groups: infant, younger than 1 y; juvenile, 1 to 4 y; subadult, 4 to 7 y; and adult, 7 to 17 y. To assess intrarater variability, each rater independently reevaluated a subset of adult macaques (n = 15) within 2 wk of initial evaluation. A weighted ? score was used to analyze intra- and interrater variability. Agreement between raters was highest for subadult and adult macaques, intermediate for juveniles, and least for infants. Intrarater agreement was high for all raters except one, for which it was moderate. Our results suggest that raters applied the BCS system most consistently to adult and subadult macaques and less so to juvenile and infant animals. However, the percentage agreement between raters to within one half of a score unit increased markedly when raters scored infants in the context of ‘as is’ rather than ‘ideal for age.’

Clingerman, Karen J; Summers, Laura

2012-01-01

245

Canonical form observer design for non-linear time-variable systems  

Microsoft Academic Search

An observer of canonical (phase-variable) form for non-linear time-variable systems is introduced. The development of this non-linear time-variable form requires regularity of the non-linear time-variable- observability matrix of the system. From the relationships derived during the development, it follows that a non-linear time-variable observer can be dimensioned by an eigenvalue assignment with respect to the canonical state coordinates if a

D. BESTLE; M. ZEITZ

1983-01-01

246

Variable Curvature Mirrors for ELT Laser Guide Star refocusing systems  

NASA Astrophysics Data System (ADS)

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

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

2011-09-01

247

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

248

Stray current control in DC mass transit systems  

Microsoft Academic Search

Stray current control is essential in direct current (DC) mass transit systems where the rail insulation is not of sufficient quality to prevent a corrosion risk to the rails, supporting and third-party infrastructure. This paper details the principles behind the need for stray current control and examines the relationship between the stray current collection system design and its efficiency. The

Ian Cotton; Charalambos Charalambous; Pete Aylott; Petra Ernst

2005-01-01

249

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

250

Electromagnetic variable degrees of freedom actuator systems and methods  

SciTech Connect

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

251

Satellite masses in the Uranus and Neptune systems  

SciTech Connect

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

Greenberg, R.

1984-10-01

252

Leaf litter processing in aquatic systems: A two variable model  

Microsoft Academic Search

A negative exponential model with one independent variable, days or accumulated time, was examined for adequacy as a descriptive\\u000a equation for aquatic leaf litter processing. The effect of adding a second independent variable, degree days or accumulated\\u000a temperature, to the model was also examined. The two variable negative exponential model was shown to have two advantages\\u000a over the single variable

Boyd J. Hanson; Kenneth W. Cummins; James R. Barnesl; Melvin W. Carter

1984-01-01

253

IMPACT OF PROCESS VARIABILITY ON LEAN MANUFACTURING SYSTEMS  

Microsoft Academic Search

This paper presents the impact of process variability on production and station\\/operator utilization in a manufacturing plant. Process variability is evaluated in terms of cycle time variance, Kanban capacities between manufacturing stations and mean cycle times. A simulation model was written in ProcessModel of the manufacturing line that was used to analyze process variability.

Mel Adams; Bernard J. Schroer; Larry R. Gunter; Bradley J. Schroer

254

Chapter 18 Another timing variable composed of state variables: Phase perception and phase driven oscillators  

Microsoft Academic Search

In this chapter, we consider a perceptible variable that is related to ?, but is different from ?. The variable is phase, .is similar to ? in that both are timing variables and both are ratios of spatial variables that could be state variables of a dynamical system. As such, either could be used to drive a damped mass-spring system

Geoffrey P. Bingham

2004-01-01

255

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

256

Vakuumnaya sistema mass-spektrometra LIDIA. (Vacuum system of the mass spectrometer LIDIA).  

National Technical Information Service (NTIS)

The high vacuum system of the mass spectrometer LIDIA is described and its parameters are presented. The construction is complitely based on the superhigh vacuum technology. It is shown that the pressure in the internal volume 3x10(sup -6) Pa can be easil...

D. D. Bogdanov A. M. Rodin S. I. Sidorchuk

1990-01-01

257

Variable structure systems theory based training strategies for computationally intelligent systems  

Microsoft Academic Search

Variable structure systems (VSS) theory, which is particularly well developed for tracking control of uncertain nonlinear systems, has inspired scientists in developing solutions to ill-posed problems like the design of training criteria under a set of conditions and performance metrics. The underlying idea has been to exploit the invariance properties introduced by the theory together with the parametric flexibility of

Mehmet Önder Efe; Okyay Kaynak

2001-01-01

258

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

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

259

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

260

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

261

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

262

Variability of deep water mass characteristics in the North Aegean Sea: The role of lateral inputs and atmospheric conditions  

NASA Astrophysics Data System (ADS)

The North Aegean Sea is considered as one of the major dense water formation sites of the Eastern Mediterranean Sea, contributing to the renewal of the Mediterranean deep water masses. We investigate the variability of the deeper water mass characteristics during the period 2002-2008, employing the Hybrid Coordinate Ocean Model for the North Aegean region. Two significant dense water formation events were detected, and the role of the major lateral water inputs, namely waters of Levantine Sea and Black Sea origin, was investigated. Atmospheric conditions were identified as the main factor of dense water formation during 2003, when strong buoyancy loss due to the low winter temperatures produced new dense water masses in the surface and intermediate layers (<400 m). During 2006, it was the intrusion of more saline Levantine waters that increased the sigma-theta of the south North Aegean region, creating idealized conditions for a potential greater dense water formation event. The Black Sea Waters spreading may affect the Mixed Layer Depth variability, promoting the stratification of the water column and playing a vital role on the dense water formation activity, working against the open-sea convection of denser waters.

Androulidakis, Yannis S.; Kourafalou, Vassiliki H.; Krestenitis, Yannis N.; Zervakis, Vassilis

2012-09-01

263

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

264

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

EPA Science Inventory

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

265

Spherically symmetric Dirac operators with variable mass and potentials infinite at infinity  

Microsoft Academic Search

We study the spectrum of spherically symmetric Dirac operators in three-dimensional space with potentials tending to infinity at infinity under weak regularity assumptions. We prove that purely absolutely continuous spectrum covers the whole real line if the potential dominates the mass, or scalar potential, term. In the situation where the potential and the scalar potential are identical, the positive part

Karl Michael Schmidt; Osanobu Yamada

1998-01-01

266

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

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

267

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

268

Fermilab's multi-petabyte scalable mass storage system  

SciTech Connect

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

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

2005-01-01

269

Vibration Control by a Variable Damping and Stiffness System with Magnetorheological Dampers  

Microsoft Academic Search

A vibration isolation system with variable damping and stiffness control is practical and has good performances. However, conventional devices of variable stiffness are usually complicated. A magnetorheological (MR) fluid damper only needs a small electric current to provide the magnetic field. It is easy to achieve variable damping with an MR damper in vibration systems. In this paper, two MR

Yanqing Liu; Hiroshi Matsuhisa; Hideo Utsuno; Jeong Gyu Park

2006-01-01

270

Battery energy storage system for variable speed driven PMSG for wind energy conversion system  

Microsoft Academic Search

There are many loads such as remote villages, islands, etc. that are located far away from the main grid. These loads require stand-alone generating system, which can provide constant voltage and frequency for local electrification. Locally available wind power can be used in such off-grid systems. As the wind speed is variable, an AC-DC-AC conversion system is required to convert

Rajveer Mittal; K. S. Sandhu; D. K. Jain

2010-01-01

271

Design of test-control system based on MCU for variable speed hydraulic system  

Microsoft Academic Search

Aiming at variable speed hydraulic compositive test stand, this paper designed the test-control system based on Microcontroller Unit (MCU), determined hardware composition of the test-control system and connection circuit of every part. The test-control system can acomplish multi-channel signal acquisition, keyboard input and realtime display of measured parameter. With the D\\/A output channel, it can realize open or closed loop

Tianhao Peng; Xiaosong Hao; Jiadong Liu; Meisheng Yang

2011-01-01

272

Increased forensic efficiency of DNA fingerprints through simultaneous resolution of length and nucleotide variability by high-performance mass spectrometry.  

PubMed

Short tandem repeat (STR) typing is the most powerful method for determining the origin of a sample for a number of molecular disciplines such as medical genetics, population genetics, tumor analysis, transplantation medicine, or forensic crime scene analysis. STR alleles are routinely differentiated based upon their fragment size by electrophoresis under denaturing conditions, which does not take nucleotide variability into consideration. This simplification leads to loss of biological information as the nature of the individual sequence motifs that build an STR is not described. An alternative detection platform would be mass spectrometry, which captures the underlying sequence variation by comparing the molecular masses of DNA fragments. Here, we demonstrate that the combination of ion-pair reversed-phase high-performance liquid chromatography and electrospray ionization quadrupole time-of-flight mass spectrometry (ICEMS) is able to simultaneously detect length and nucleotide variability in STRs. Overall, 21 forensically relevant STRs that are also used in other scientific fields were screened in an Austrian population sample for the occurrence of nucleotide variability within or close to the repeat region. A total of 11 of the investigated loci (SE33, D2S1338, vWA, D21S11, D3S1358, D16S539, D8S1179, D7S820, D13S317, D5S818, and D2S441) brought additional allele (sequence) variants. Forensic efficiency, as determined by typical statistical parameters, was significantly increased by 20 to 30%. The beauty of ICEMS-STR-analysis is the fact that it represents one of the few technological advancements that allows direct comparison of newly generated data with existing data such as stored in DNA databases, which have a retarding effect on new developments. PMID:18076121

Oberacher, Herbert; Pitterl, Florian; Huber, Gabriela; Niederstätter, Harald; Steinlechner, Martin; Parson, Walther

2008-03-01

273

The HD 192263 System: Planetary Orbital Period and Stellar Variability Disentangled  

NASA Astrophysics Data System (ADS)

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

Dragomir, Diana; Kane, Stephen R.; Henry, Gregory W.; Ciardi, David R.; Fischer, Debra A.; Howard, Andrew W.; Jensen, Eric L. N.; Laughlin, Gregory; Mahadevan, Suvrath; Matthews, Jaymie M.; Pilyavsky, Genady; von Braun, Kaspar; Wang, Sharon X.; Wright, Jason T.

2012-07-01

274

Mass  

SciTech Connect

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

Quigg, Chris (Fermilab)

2007-12-05

275

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

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

276

On the nature of the variability in the Martian thermospheric mass density: Results from the Mars Global Surveyor Electron Reflectometer  

NASA Astrophysics Data System (ADS)

Knowledge of Mars' thermospheric mass density (~120--200 km altitude) is important for understanding the current state and evolution of the Martian atmosphere and for spacecraft such as the upcoming MAVEN mission that will fly through this region every orbit. Global-scale atmospheric models have been shown thus far to do an inconsistent job of matching mass density observations at these altitudes, especially on the nightside. Thus there is a clear need for a data-driven estimate of the mass density in this region. Given the wide range of conditions and locations over which these must be defined, the dataset of thermospheric mass densities derived from energy and angular distributions of super-thermal electrons measured by the MAG/ER experiment on Mars Global Surveyor, spanning 4 full Martian years, is an extremely valuable resource that can be used to enhance our prediction of these densities beyond what is given by such global-scale models. Here we present an empirical model of the thermospheric density structure based on the MAG/ER dataset. Using this new model, we assess the global-scale response of the thermosphere to dust storms in the lower atmosphere and show that this varies with latitude. Further, we examine the short- and longer-term variability of the thermospheric density and show that it exhibits a complex behavior with latitude and season that is indicative of both atmospheric conditions at lower altitudes and possible lower atmosphere wave sources.

England, S.; Lillis, R. J.

2011-12-01

277

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

278

Dynamical paths and universality in continuous-variable open systems  

NASA Astrophysics Data System (ADS)

We address the dynamics of quantum correlations in continuous-variable open systems and analyze the evolution of bipartite Gaussian states in independent noisy channels. In particular, we introduce the notion of dynamical path through a suitable parametrization for symmetric states and focus attention on phenomena that are common to Markovian and non-Markovian Gaussian maps under the assumptions of weak coupling and the secular approximation. We find that the dynamical paths in the parameter space are universal, that is, they depend only on the initial state and on the effective temperature of the environment, with non-Markovianity that manifests itself in the velocity of running over a given path. This phenomenon allows one to map non-Markovian processes onto Markovian ones and may reduce the number of parameters needed to study a dynamical process, e.g., it may be exploited to build constants of motions valid for both Markovian and non-Markovian maps. Universality is also observed in the value of Gaussian discord at the separability threshold, which itself is function of the initial conditions only, in the limit of high temperature. We also prove the existence of excluded regions in the parameter space, i.e., sets of states that cannot be linked by any Gaussian dynamical map.

Cazzaniga, Andrea; Maniscalco, Sabrina; Olivares, Stefano; Paris, Matteo G. A.

2013-09-01

279

An effective breast mass diagnosis system using Zernike moments  

Microsoft Academic Search

In this paper, a novel CADx system has been proposed for the diagnosis of masses in mammography images. The objective is intensifying the performance of CADx algorithms as well as reducing the false positive rate by utilizing Zernike moments as descriptors of shape and margin characteristics. The input ROI is segmented manually by expert radiologists. Then, it is subjected to

Amir Tahmasbi; Fatemeh Saki; Shahriar B. Shokouhi

2010-01-01

280

The ``Biway'' System of Electric Platforms for Mass Transit  

Microsoft Academic Search

This paper describes the ``biway'' system of mass transit by continuously moving electrically operated platforms which is cited as being suitable for use in the congested sections of large cities. It is planned to have 2 adjacent moving platforms, one of which operates continuously at a speed of about 15 miles per hour, the other of which varies between standstill

Norman W. Storer

1935-01-01

281

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

282

North Shore refuse energy system. [Saugus, Mass. , refuse combustion plant  

Microsoft Academic Search

The Saugus, Mass., refuse plant is designed for the practically pollution-free combustion of municipal and industrial wastes for the generation of steam for a nearby industrial plant for power generation, heating, and plant processing. The initial design includes recovery of ferrous metals with provision for expansion of the materials recovery systems to include other items as the markets and technology

MacAdam

1976-01-01

283

The National Measurement System for Mass, Volume and Density.  

National Technical Information Service (NTIS)

This document, one of several similar documents resulting from the NBS study of the National Measurement System, reflects the results of intensive studies carried out from 1972-1975 relative to Mass, Volume and Density measurements in the United States. T...

P. E. Pontius J. R. Whetstone J. A. Simpson

1978-01-01

284

Design and Evolution of Jefferson Lab's Jasmine Mass Storage System.  

National Technical Information Service (NTIS)

We describe the Jasmine mass storage system, in operation since 2001. Jasmine has scaled to meet the challenges of grid applications, petabyte class storage, and hundreds of MB/sec throughput using commodity hardware, Java technologies, and a small but fo...

B. K. Hess M. Haddox-Schatz M. A. Kowalski

2005-01-01

285

Mass-resolving charge-exchange system on PDX  

SciTech Connect

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

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

1982-10-01

286

Refrigerant mass migration modeling and simulation for air conditioning systems  

Microsoft Academic Search

Refrigerant mass migration and redistribution are regarded as key factors affecting the cycling performance of air conditioning and refrigeration systems. A dynamic model of an R134a automotive air conditioning system is presented as an example in this paper to capture the refrigerant migration during compressor shut-down and start-up operations. Model validation against experimental data demonstrates the capabilities of the modeling

Bin Li; Steffen Peuker; Predrag S. Hrnjak; Andrew G. Alleyne

2011-01-01

287

General applications 2: 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

288

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

Code of Federal Regulations, 2013 CFR

...of urban system nonhighway public mass transit projects. ...Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PUBLIC TRANSPORTATION MASS TRANSIT...Federal-Aid Urban System Nonhighway Public Mass Transit Projects...

2013-04-01

289

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

NASA Astrophysics Data System (ADS)

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

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

2012-01-01

290

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

NASA Astrophysics Data System (ADS)

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

Reddy, M. Gnaneswara

2013-03-01

291

Relative Quantification: Characterization of bias, variability and fold changes in mass spectrometry data from iTRAQ labeled peptides  

PubMed Central

Shotgun proteomics via mass spectrometry (MS) is a powerful technology for biomarker discovery which has the potential to lead to non-invasive disease screening mechanisms. Successful application of MS-based proteomics technologies for biomarker discovery requires accurate expectations of bias, reproducibility, variance, and the true detectable differences in platforms chosen for analyses. Characterization of the variability inherent in MS assays is vital and should affect interpretation of measurements of observed differences in biological samples. Here we describe observed biases, variance structure and the ability to detect known differences in spike-in data sets for which true relative abundance among defined samples were known and were subsequently measured with the iTRAQ® technology on two MS platforms. Global biases were observed within these data sets. Measured variability was a function of mean abundance. Fold changes were biased towards the null and variance of a fold change was a function of protein mass and abundance. The information presented herein will be valuable for experimental design and analysis of the resulting data.

Mahoney, Douglas W.; Therneau, Terry M.; Heppelmann, Carrie J.; Higgins, LeeAnn; Benson, Linda M.; Zenka, Roman M.; Jagtap, Pratik; Nelsestuen, Gary L.; Bergen, H. Robert; Oberg, Ann L.

2011-01-01

292

Revolution speed ratio control system for a continuously variable transmission  

SciTech Connect

This patient describes revolution speed ratio control system for a continuously variable transmission comprising a driving pulley provided on an input shaft; a driven pulley provided on an output shaft disposed in parallel with the input shaft; an endless belt wound on both the pulleys; each of the pulleys comprising a fixed member secured to the input or output shaft and having a conical surface, and a movable member which has a conical surface facing that of the fixed member and is provided so that the movable member is rotated together with the input or output shaft and can be slid on the shaft in the axial direction thereof; and the endless belt has both its oblique side surfaces frictionally engaged with the conical surfaces of the fixed and movable members; an electronic control circuit including a means for calculating the actual revolution speed ratio between the driving and driven pulleys of the transmission, a means for generating a first electric control signal corresponding to the difference between the actual revolution speed ratio and an aimed revolution speed ratio between the pulleys determined by information of the input torque of the input shaft and required torque for the output shaft, and a means for generating a second electric control signal determined by the sum of an electric signal corresponding to the actual revolution speed ratio and an electric signal corresponding to the difference; and a hydraulic control circuit including a pressure oil source, a first cylinder which is provided on the input shaft and supplied with working oil from the pressure oil source to push the movable member of the driving pulley toward the fixed member thereof.

Hattori, K.; Suzuki, H.; Yamaguchi, H.; Ogasawara, T.

1988-12-13

293

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

294

Study of continuous variable entanglement in multipartite harmonic oscillator systems  

NASA Astrophysics Data System (ADS)

In this thesis we investigate the entanglement of Schrodinger cat states that derive from harmonic oscillator models. In order to extend the finite dimensional framework of entanglement to the infinite dimensional case we consider only initial conditions that have some type of symmetry. Systems with symmetry usually have fewer important parameters. In our case, symmetry allows us to discard the bulk of the Hilbert space as irrelevant to our particular entanglement problem. We are then left with an effectively finite dimensional Hilbert space, and the developed entanglement framework can therefore be followed. The dimension we derive for the reduced Hilbert space in each subsystem is equal to the number of coherent states in the Schrodinger cat superposition. We investigate the entanglement vs. time of our Schrodinger cat state for closed and open systems. For closed systems, we place no limit on the number of coherently summed linearly independent coherent states. So the dimension of our effective Hilbert space can be quite high. We also place no restriction on the number of subsystems (or parties). Consequently, we use the entanglement measure developed by Barnum, Knill, Ortiz, and Viola (BKOV). This is the only measure to our knowledge that has no restriction on the dimension of the Hilbert space or the number of subsystems. We also place no constraint on the magnitude of our coherent states. The coherent value may be quite large, or quite small. We find that the entanglement of the Schrodinger cat state has nontrivial dependence on the above mentioned three variables. That is, the entanglement is a non-separable function of the values of the coherent states, the number of coherent states in the superposition, and the number of partitions of the Hilbert space. For open systems, we model the reservoir as a harmonic oscillator zero temperature bath. Due to the interactions with the bath the Schrodinger cat state becomes a mixed density matrix. To investigate the time dependent entanglement of our density matrix, we apply the convex roof extension of the BKOV measure. This required development of an algorithm to search the space of decompositions of the density matrix. The time dependence depends on the symmetry of the system, naturally splitting the Hilbert space into a direct sum of two subspaces. One subspace interacts strongly with the bath resulting in rapid decoherence. The other complimentary subspace does not interact at all with the bath and is decoherence free. For initial states in the decohering subspace we find that for large values of the coherent state, the decay of entanglement corresponds to the decay rate of correlations in the bath. We are able to derive this result analytically. For small values of the coherent states, the loss of entanglement corresponds to the decay of the coherent state amplitude. Finally, we consider initial states that live in the combined Hilbert space. Decoherence then provides a means of engineering a new state through decay of the component that resides in the decohering subspace of the complete Hilbert space. We develop a type of super-symmetry that gives us a new reduced Hilbert space that naturally encompasses the symmetry of the decohering subspace and the symmetry of the decoherence free subspace. In this new, "super" Hilbert space, we are able to characterize the entanglement of our density matrix vs time.

Landau, Mayer Amitai

295

Water masses and decadal variability in the East Sea (Sea of Japan)  

NASA Astrophysics Data System (ADS)

Water masses in the East Sea are newly defined based upon vertical structure and analysis of CTD data collected in 1993 1999 during Circulation Research of the East Asian Marginal Seas (CREAMS). A distinct salinity minimum layer was found at 1500 m for the first time in the East Sea, which divides the East Sea Central Water (ESCW) above the minimum layer and the East Sea Deep Water (ESDW) below the minimum layer. ESCW is characterized by a tight temperature salinity relationship in the temperature range of 0.6 0.12 °C, occupying 400 1500 m. It is also high in dissolved oxygen, which has been increasing since 1969, unlike the decrease in the ESDW and East Sea Bottom Water (ESBW). In the eastern Japan Basin a new water with high salinity in the temperature range of 1 5 °C was found in the upper layer and named the High Salinity Intermediate Water (HSIW). The origin of the East Sea Intermediate Water (ESIW), whose characteristics were found near the Korea Strait in the southwestern part of the East Sea in 1981 [Kim, K., & Chung, J. Y. (1984) On the salinity-minimum and dissolved oxygen-maximum layer in the East Sea (Sea of Japan), In T. Ichiye (Ed.), Ocean Hydrodynamics of the Japan and East China Seas (pp. 55 65). Amsterdam: Elsevier Science Publishers], is traced by its low salinity and high dissolved oxygen in the western Japan Basin. CTD data collected in winters of 1995 1999 confirmed that the HSIW and ESIW are formed locally in the Eastern and Western Japan Basin. CREAMS CTD data reveal that overall structure and characteristics of water masses in the East Sea are as complicated as those of the open oceans, where minute variations of salinity in deep waters are carefully magnified to the limit of CTD resolution. Since the 1960s water mass characteristics in the East Sea have changed, as bottom water formation has stopped or slowed down and production of the ESCW has increased recently.

Kim, Kuh; Kim, Kyung-Ryul; Kim, Young-Gyu; Cho, Yang-Ki; Kang, Dong-Jin; Takematsu, Masaki; Volkov, Yuri

2004-05-01

296

Design and research on a variable ballast system for deep-sea manned submersibles  

NASA Astrophysics Data System (ADS)

Variable ballast systems are necessary for manned submersibles to adjust their buoyancy. In this paper, the design of a variable ballast system for a manned submersible is described. The variable ballast system uses a super high pressure hydraulic seawater system. A super high pressure seawater pump and a deep-sea brushless DC motor are used to pump seawater into or from the variable ballast tank, increasing or decreasing the weight of the manned submersible. A magnetostrictive linear displacement transducer can detect the seawater level in the variable ballast tank. Some seawater valves are used to control pumping direction and control on-off states. The design and testing procedure for the valves is described. Finally, the future development of variable ballast systems and seawater hydraulic systems is projected.

Qiu, Zhong-Liang

2008-12-01

297

a Modular Daq System for Next Generation Bolometric ? Mass Experiments  

NASA Astrophysics Data System (ADS)

This work will describe the development and the present status of the new DAQ system for the MARE experiment. This kind of DAQ system is oriented to a run-time selection and digitization of analog signals coming from a huge number of microbolometers in a cryogenic environment, readout by an array of semiconductor thermistors. The main properties of this DAQ are a full analog signal sampling feature with high speed FPGA-controlled trigger logic for a fast hardware signal selection and trigger. This DAQ system has to be capable to collect and measure the beta spectrum of 187Re with high statistics and energy resolution, essential for the neutrino mass determination.

Foggetta, Luca; Giuliani, Andrea; Prest, Michela; Vallazza, Erik

2008-06-01

298

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

PubMed Central

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

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

2009-01-01

299

Probing the mass-loss history of the unusual Mira variable R Hydrae through its infrared CO wind  

NASA Astrophysics Data System (ADS)

Context: The unusual Mira variable R Hya is well known for its declining period between ad 1770 and 1950, which is possibly attributed to a recent thermal pulse. Aims: The goal of this study is to probe the circumstellar envelope (CSE) around R Hya and to check for a correlation between the derived density structure and the declining period. Methods: We investigate the CSE around R Hya by performing an in-depth analysis of (1.) the photospheric light scattered by three vibration-rotation transitions in the fundamental band of CO at 4.6 ?m; and (2.) the pure rotational CO J = 1-0 through 6-5 emission lines excited in the CSE. The vibrational-rotational lines trace the inner CSE within 3.5´´, whereas the pure rotational CO lines are sensitive probes of the cooler gas further out in the CSE. Results: The combined analysis bear evidence of a change in mass-loss rate some 220 yr ago (at 150 Rstar or 1.9 arcsec from the star). While the mass-loss rate before ad 1770 is estimated to be 2 × 10-7 M?/yr, the present day mass-loss rate is a factor of 20 lower. The derived mass-loss history nicely agrees with the mass-loss rate estimates by Zijlstra et al. (2002) on the basis of the period decline. Moreover, the recent detection of an AGB-ISM bow shock around R Hya at 100 arcsec to the west by Wareing et al. (2006) shows that the detached shell seen in the 60 ?m IRAS images can be explained by a slowing-down of the stellar wind by surrounding matter and that no extra mass-loss modulation around 1-2 arcmin needs to be invoked. Conclusions: Our results give empirical evidence to the thermal-pulse model, which is capable of explaining both the period evolution and the mass-loss history of R Hya. Appendix A is only available in electronic form at http://www.aanda.org

Decin, L.; Blomme, L.; Reyniers, M.; Ryde, N.; Hinkle, K. H.; de Koter, A.

2008-06-01

300

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

Microsoft Academic Search

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

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

301

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

302

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

303

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

304

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

SciTech Connect

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

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

2012-12-01

305

Active Intelligent Service Offer System Addition Environment variable and Local variable  

Microsoft Academic Search

It has been highlighted and spread that the cutting edge system and intelligence home system raised from dramatic development of IT technology. Through the progressed application of home networking tech. and diverse multi-media, there are plenty of efforts to pursue the realization of human convenience. As a home networking services is on the increase, so is the demand for context-aware

Kyung-sang Sung; Oh Hae-seok

2006-01-01

306

Designing and Planning of Material Handling Systems for Mass Customization  

Microsoft Academic Search

\\u000a Mass customization (MC) involves the challenge of high product proliferation and frequent production volumes change. Flexible\\u000a manufacturing has been treated as the main solution for these challenges. However, without a flexible material handling system\\u000a (MHS), flexible manufacturing cannot be implemented successfully. Therefore, the designing and planning of the flexible MHS\\u000a has attracted intensive research. This chapter first reviews different types

Neville K. S. Lee; James B. Dai

307

Variable gearing during locomotion in the human musculoskeletal system.  

PubMed

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

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

1994-07-29

308

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

Microsoft Academic Search

Plant lighting is a critical issue for cost effectiveness of bioregenerative systems. A plant lighting system using sunlight has been investigated and compared to systems using electrical lighting. Co-generation of electricity and use of in situ resource utilization (ISRU) were also considered. The fixed part of equivalent system mass was found to be reduced by factors of from 3.1 to

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

2008-01-01

309

Adoption of site-specific variable rate sprinkler irrigation systems  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

310

Enhancing adoption of site-specific variable rate sprinkler systems  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

311

Preprocessor System 'EOS' For a Variable-Array-Size Program.  

National Technical Information Service (NTIS)

As a part of the project TRITON a preprocessor (EOS preprocessor) has been developed. This preprocessor converts an EOS source program in which variables and arithmetic expressions are usable to define sizes of arrays into a usual FORTRAN source program i...

T. Takeda T. Tsunematsu G. Kurita

1982-01-01

312

ANVAS: artificial neural variables adaptation system for descriptor selection.  

PubMed

A new algorithm model-oriented for variable selection is presented in this study. It is based on the combination of genetic algorithms (GA) for hyperspace exploration, and counterpropagation artificial neural network (CP ANN) for deriving the fitness score. The proposed method performed very well on both well defined synthetic data sets and real academic data sets. PMID:14635726

Mazzatorta, Paolo; Vracko, Marjan; Benfenati, Emilio

313

Mass transfer in interacting binary W Ser-type systems.  

NASA Astrophysics Data System (ADS)

By the method, proposed by Nazarenko (1993) and using the observational data, obtained by different authors, the physical conditions in the stream in the neighbourhood of the point L1 were calculated for three interacting binary systems of W Ser-type: ? Lyr, V367 Cyg, RY Sct. The calculation showed, that in the investigated systems saturation in the vicinity of the point L1 takes place. That means, that a further increase of the radius of the mass losing companion does not lead to a considerable increase of concentration of matter in the point L1.

Karetnikov, V. G.; Menchenkova, E. V.; Nazarenko, V. V.

1993-09-01

314

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

USGS Publications Warehouse

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

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

2001-01-01

315

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

316

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

317

Luminous blue variables and related high-mass evolved stars in M31 and their surprising environments  

NASA Astrophysics Data System (ADS)

Luminous Blue Variables (LBVs) are erratically eruptive massive stars near the Eddington limit generally thought to be the descendants of blue supergiants and the progenitors of Wolf-Rayet stars. Recent observations suggest that this standard path is not necessarily true for all LBVs, including the intrinsically bright ones. In order to understand the evolutionary positions of these objects and their relation to other high mass-losing stars in the upper H-R diagram, we would like to know their bolometric luminosities, effective temperatures, current masses, progenitor masses, ages, and abundances. With the use of 3.5-m class telescopes (WIYN and ARC) we are able to roughly constrain all but the abundances for these LBV-type stars in M31. We began the study by developing a method for identifying candidate LBVs in nearby galaxies through deep narrow-band images. The method was used to make a target list of such objects in the NE half of M31. We obtained follow-up spectroscopy that confirmed the success of our search criteria. We obtained high angular resolution broad band and Halpha images of the environments of the first five LBV-type objects and two previously identified M31 LBVs using the WIYN 3.5-m telescope. The spectral energy distribution (SED) of K895 exhibits near infrared excess emission similar to that observed in B[e] supergiants. The calibrated WIYN photometry was used to measure color-magnitude diagrams for the resolved luminous stars. We charted the locations of HII regions and HI holes as indicators of stellar ages in the areas around our program objects. We used the Q-method, after a rough empirical validation of its applicability, to constrain the luminosities and effective temperatures of our program objects. We constrained the present masses and examined the ages predicted for our program objects by the Meynet et al. (1994) stellar evolution models. Surprisingly, the majority of the LBV-type objects were found to be surrounded by stars that appeared to be older than the LBV-type objects themselves. The age discrepancies between LBV or LBV-type object and its environment might be explained if the LBVs or candidate LBVs are runaways, are products of discrete massive star forming events, have somehow lived longer than theoretically expected, or are exotic binaries such as Thorne-Zytkow objects or mass-transferring close binaries. (Abstract shortened by UMI.)

King, Nichole Lynn

318

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

319

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

320

Lateral Thrust and Aerodynamics Blended Control System Design Based on Variable Structure Model Following  

Microsoft Academic Search

Variable structure model following technique is applied to the synthesis of a longitudinal autopilot for a missile with lateral thrust and aerodynamics blended. Firstly, the lateral thrust and aerodynamics blended control system model and the ideal reference model are established. Secondly, a variable structure model following controller is designed, and the stability and robustness of system are analyzed. Finally, the

Yuhang Wang; Yu Yao; Kemao Ma

2006-01-01

321

Gain scheduling control of variable-speed wind energy conversion systems using quasi-LPV models  

Microsoft Academic Search

The paper deals with the control of variable-speed wind energy conversion systems (WECS) in the context of linear parameter varying (LPV) systems, a recent formulation of the classic gain scheduling technique. The LPV approach is specially useful in variable-speed WECS control, which is characterized by nonlinear dynamic behavior and opposite objectives. In particular, the following objectives are considered: conversion efficiency

F. D. Bianchi; R. J. Mantz; C. F. Christiansen

2005-01-01

322

Vibration control of two degrees of freedom system using variable inertia vibration absorbers: Modeling and simulation  

NASA Astrophysics Data System (ADS)

Variable inertia vibration absorbers (VIVA) are previously used for the vibration control of single degree of freedom (dof) primary systems. The performance of such absorbers is studied in many investigations. This paper presents the dynamic modeling and simulation of a proposed modified design of such VIVA’s for the vibration control of two dof primary systems. Lagrange formulation is used to obtain its dynamic model in an analytical form. This model, which is highly nonlinear, is used to develop a computational algorithm to study the absorber performance characteristics. This algorithm is programmed and simulated in Matlab. The obtained results are numerically verified using SAMS2000 software. The effect of mass and stiffness of the proposed VIVA on its performance and tuning is discussed. An optimization algorithm is developed to select the best absorber parameters for vibration suppression of a specific primary system. The obtained results show a good agreement with those obtained using similar techniques. In addition, a linearized model of VIVA dynamics is developed, tested and simulated for the same data used in its nonlinear model. The relative deviation between results of the linear and nonlinear models is less than 1%, which confirms the realistic use of this linearized model. The experimental testing and verification of the simulation results of the proposed VIVA is the subject of another paper.

Megahed, S. M.; Abd El-Razik, A. Kh.

2010-11-01

323

Complex systems and the technology of variability analysis  

Microsoft Academic Search

Characteristic patterns of variation over time, namely rhythms, represent a defining feature of complex systems, one that is synonymous with life. Despite the intrinsic dynamic, interdependent and nonlinear relationships of their parts, complex biological systems exhibit robust systemic stability. Applied to critical care, it is the systemic properties of the host response to a physiological insult that manifest as health

Andrew JE Seely; Peter T Macklem

2004-01-01

324

The stabilization of digraphs of variable parameter systems  

Microsoft Academic Search

Directed acyclic graphs of dynamical systems are considered. Such graphs possess a natural and unique layering of their nodes. Each node is taken to be associated with a dynamical system in such a way that each parameter of a given system is some nonlinear function of the states of systems connected to it and lying in higher layers of the

P. Caines; R. Printis

1978-01-01

325

Electrowetting-Based Variable-Focus Lens for Miniature Systems  

Microsoft Academic Search

The meniscus between two immiscible liquids of different refractive indices can be used as a lens. A change in curvature of this meniscus by electrostatic control of the solid\\/liquid interfacial tension leads to a change in focal distance. It is demonstrated that two liquids in a tube form a self-centred variable-focus lens. The optical properties of this lens were investigated

B. H. W. Hendriks; S. Kuiper; M. A. J. van As

2005-01-01

326

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

327

Impact of thermal energy storage properties on solar dynamic space power conversion system mass  

Microsoft Academic Search

A 16 parameter solar concentrator\\/heat receiver mass model is used in conjunction with Stirling and Brayton Power Conversion System (PCS) performance and mass computer codes to determine the effect of thermal energy storage (TES) material property changes on overall PCS mass as a function of steady state electrical power output. Included in the PCS mass model are component masses as

A. J. Juhasz; C. E. Coles-Hamilton; D. E. Lacy

1987-01-01

328

Analysis of two-element zoom systems based on variable power lenses.  

PubMed

Traditional optical systems with variable optical characteristics are composed of several optical elements that can be shifted with respect to each other mechanically. A motorized change of position of individual elements (or group of elements) then makes possible to achieve desired optical properties of such zoom lens systems. A disadvantage of such systems is the fact that individual elements of these optical systems have to move very precisely, which results in high requirements on mechanical construction of such optical systems. Our work is focused on a paraxial and third order aberration analysis of possible optical designs of two-element zoom lens systems based on variable power lenses with a variable focal length. First order chromatic aberrations of the variable power lenses are also described. Computer simulation examples are presented to show that such zoom lens systems without motorized movements of lenses appear to be promising for the next-generation of zoom lens design. PMID:20389699

Miks, Antonin; Novak, Jiri

2010-03-29

329

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

330

Entanglement generation and Hamiltonian simulation in continuous-variable systems  

SciTech Connect

Several recent experiments have demonstrated the promise of atomic ensembles for quantum teleportation and quantum memory. In these cases, the collective internal state of the atoms is well described by continuous variables corresponding to the operators X{sub 1},P{sub 1} and the interaction with the optical field (X{sub 2},P{sub 2}) by a quadratic Hamiltonian X{sub 1}X{sub 2}. We show how this interaction can be used optimally to create entanglement and squeezing. We derive conditions for the efficient simulation of quadratic Hamiltonians and the engineering of all Gaussian operations and states.

Kraus, Barbara; Hammerer, Klemens; Giedke, Geza; Cirac, J. Ignacio [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Strasse, D-85748 Garching (Germany)

2003-04-01

331

Enhanced Masses and Superconductivity in Highly Correlated Fermionic Systems.  

NASA Astrophysics Data System (ADS)

Available from UMI in association with The British Library. Requires signed TDF. In this thesis, we investigate and review some of the properties of two highly correlated fermionic systems, the heavy fermion compounds (part I) and the high temperature superconductors (part II). In part I, we introduce the slave boson functional integral method by reviewing its application to the Cerium impurity system. After considering ways of extending it to the Uranium impurity system, we apply it to the Cerium and Uranium lattice (heavy fermion) systems. For the former, we use an extension of the periodic Anderson model which includes a degree of f-f hopping and find that, even for small values of the hopping, the system can behave like an effective Hubbard model. We discover that there is a fundamental difference between the f^0 -f^1 (Cerium) systems and the f^{rm n}-f ^{rm n+1} (n ne 0) systems which is manifest in the effective mass enhancements in the mixed valent regime. In part II, we review the theoretical and experimental aspects of the high temperature superconductors as of April 1988. We consider the evidence for a strong electron-phonon interaction and a strong electron-electron interaction and discuss possible mechanisms for the formation of the superconducting state.

Harrington, Andrew Philip

332

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

NASA Astrophysics Data System (ADS)

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

Cosler, D.; Ibaraki, M.

2004-12-01

333

Estimation of the virial mass for systems of galaxies  

SciTech Connect

Two problems concerning the application of the virial theorem to systems of galaxies are considered: the effect of clumpiness in the distribution of member galaxies on the estimated potential energy of the system, and the effect of radial-velocity errors on the estimated kinetic energy. A clumpiness factor C is introduced: the ratio of the true potential energy of the cluster to the potential energy determined from a smoothed density distribution. For the Neyman--Scott model of galaxy clustering, Capprox. =2--3, and virial masses based on counts of galaxies in ring or strip zones should be diminished by this factor. For the Coma cluster the ratio of the virial to the observed mass is M/sub VT//Mapprox. =3.5, with an uncertainty of up to a factor of approx. =2. An accurate, unbiased estimate is obtained for the kinetic energy of a system of galaxies, allowing for errors in the radial-velocity measurements. For the NGC 1023 group this estimate is M/sub VT//Mapprox. =0.6, confirming that the group is stable.

Terebizh, V.Y.

1979-03-01

334

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

335

Crossed undulator system for a variable polarization synchrotron radiation source  

SciTech Connect

A crossed undulator system can produce synchrotron radiation whose polarization is arbitrary and adjustable. The polarization can be linear and modulated between two mutually perpendicular directions, or it can be circular and can be modulated between right and left circular polarizations. The system works on low emittance electron storage rings and can cover a wide spectral range. Topics discussed include the basic principle of the system, the design equations and the limitations in performance.

Kim, K.J.

1984-05-01

336

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

337

[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

338

Level-Confluence of Conditional Rewrite Systems with Extra Variables in Right-Hand Sides  

Microsoft Academic Search

Level-conuence is an important property of conditional term rewriting systems that allow extra variables in the rewrite rules because it guarantees the completeness of narrowing for such systems. In this paper we present a syntactic condition ensuring level-conuence for orthogonal, not necessarily terminating, conditional term rewriting systems that have extra variables in the right-hand sides of the rewrite rules. To

Taro Suzuki; Aart Middeldorp; Tetsuo Ida

1995-01-01

339

Active variable buoyancy control system for MBARI's ROV  

Microsoft Academic Search

The Monterey Bay Aquarium Research Institute (MBARI), with QUEST Integrated Inc., has designed and developed an active buoyancy control system for assisting in the operational control of MBARI's new remotely operated vehicle (ROV) Tiburon. This system is intended to assist in payload, ascent\\/descent and station keeping applications during scientific operations down to a maximum depth of 4000 meters

W. J. Kirkwood; D. E. Steele

1994-01-01

340

New low-cost metrology system for mass production  

NASA Astrophysics Data System (ADS)

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

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

2008-03-01

341

Experience with the UniTree mass storage system  

SciTech Connect

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

Holmes, H.H.; Loken, S.

1992-09-01

342

Inter-annual variability of biogenic and mass fluxes in the northern Joides Basin (Ross Sea - Antarctica)  

NASA Astrophysics Data System (ADS)

The Southern Ocean plays an important role in world climate as it is a key area for the formation of oceanic bottom waters, and it is an important region for air-sea CO2 exchange, accounting for 20 to 25 % of the annual oceanic uptake of CO2. In this contest, biogeochemical changes that occur in the water column play an important role. In this study we analyze the biogeochemical composition of sediment trap samples collected in the Ross Sea continental shelf. The samples have been collected in the site B, located at 74°00.178'S and 175°05.864'E in the northern Joides Basin, during 1999 and 2008. This area is characterized by high biological productivity during spring, algal blooms in summer and high spatial and temporal variability of fluxes. A series of biogeochemical analyzes were carried out on these samples including organic carbon, nitrogen, bio-silica and total mass flux. In this area, generally, the maximum flux to the seabed occurs at least two months after the peak of productivity, which is usually in December or early in the year. The biomass produced is retained at the upper water column for a longer time respect to other ecosystems with high productivity due to the difference between the community development of phytoplankton and the growth of zooplankton. Our data document that the period of highest mass and biogenic flows changes over time occurring in January during 1995, in February-March during 1999, and in March-April during 2008. The integration between biogeochemical results and environmental forcings of the study area suggests that the delay can be related to the extent and concentration of seasonal ice. In addition, changes related to the physicochemical parameters of the water column (such as temperature and salinity) and nutrients input could have caused late bloom of diatoms and physiological variations in phytoplankton communities.

Chiarini, F.; Capotondi, L.; Tesi, T.; Giglio, F.; Langone, L.; Ravaioli, M.

2012-04-01

343

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

344

Analyses of Variable Refrigerant Flow and Exergy in Air Conditioning Systems  

Microsoft Academic Search

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

Rashid Ali Alshatti

2011-01-01

345

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

346

Mining: Variable Wall Mining Machine with Dual Duct Ventilation System.  

National Technical Information Service (NTIS)

This exciting new invention is highly automated, requiring only one worker to operate the cutting, conveying, and support systems. Read how the machine saves energy and increases miner safety by isolating methane and dust from worker ventilation via a dua...

Lee Recca

1999-01-01

347

Characterizing the variability of multiple sandbar systems with linear stability  

NASA Astrophysics Data System (ADS)

Multiple sandbar systems have been observed in a variety of settings worldwide. The changes in multiple sandbar systems sometimes result in rhythmic patterns, usually called crescentic bars. The nature of their occurrence has been studied both through observations (e.g. Short and Aagaard, 1993) and numerical studies (e.g. Klein and Schuttelaars, 2006). The development of crescentic bars in multiple sandbar systems is part of sequential beach changes (Short and Aagaard, 1993) displaying a range of configurations that can involve coupling between the sandbars and, sometimes, also the shoreline (Ruessink et al., 2007). Here we use a numerical model based on linear stability analysis to study the role of hydrodynamic conditions and initial cross-shore sandbar profile on the evolution of the double sandbar system. Preliminary results shows various configurations that have been observed in the field and that can be related to a combination of offshore hydrodynamic conditions and initial cross-shore beach profiles.

Coco, G.; Calvete Manrique, D.

2009-04-01

348

Application of electrical variable transmission in wind power generation system  

Microsoft Academic Search

In the widely applied non-direct driven wind power generation system, a gearbox is connected between the wind turbine and the high speed doubly-fed induction generator (DFIG) so that the system could be smaller and supply power with constant voltage and constant frequency as the wind turbine speed varies. However, the multi-level mechanical gearbox is rather vulnerable and poses many difficulties

Xikai Sun; Ming Cheng; Wei Hua; Longya Xu

2010-01-01

349

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

350

Variable universe adaptive fuzzy sliding mode control strategy for uncertain chaotic systems  

Microsoft Academic Search

Based on integrating the property of sliding mode control (SMC) with the thought of variable universe in adaptive fuzzy control, a design method of variable universe adaptive fuzzy sliding mode control (FSMC) strategy for uncertain chaotic systems is proposed. There are two sets of control rule bases. The first set is utilized to approach the equivalent control of SMC. By

Juntuan Zhang; Defu Cheng; Yunfeng Liu; Yali Qin

2008-01-01

351

System for analyzing spatially-variable harvest data by pass  

US Patent & Trademark Office Database

An apparatus is provided which analyzes spatially-variable harvest data for one of the passes made by an agricultural harvesting vehicle through an agricultural field. The harvesting vehicle supports an implement for harvesting crop during each pass through the field. The apparatus includes a digital memory, an electronic display, a processor circuit and an operator-actuatable input device. The digital memory stores a geo-referenced map of the field including harvest data representative of at least one sensed parameter of the harvested crop and pass data representative of the plurality of passes of the harvesting vehicle through the field. The processor circuit is configured to read the geo-referenced map of the field from the memory and to generate a display signal therefrom which, when applied to the electronic display, generates visible indicia of at least a portion of the field and at least one sensed parameter of the harvested crop. The operator-actuatable input device is coupled to the processor circuit and configured to generate an input signal which identifies one of the passes of the harvesting vehicle. The processor circuit analyzes the harvest data representative of the at least one sensed parameter of the harvested crop that was harvested by the implement during the identified pass of the vehicle, and generates the display signal to cause the electronic display to display a result of the analysis in association with the identified pass of the vehicle.

Wendte; Keith W. (Hinsdale, IL)

1999-11-30

352

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

SciTech Connect

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

Owocki, S. P.; Townsend, R. H. D. [Bartol Research Institute, Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Romero, G. E.; Araudo, A. T. [Inst. Argentino de RadioastronomIa (CCT La Plata, CONICET), C.C.5, 1894 Villa Elisa, Buenos Aires (Argentina)

2009-05-01

353

Organization of computer systems: the fixed plus variable structure computer  

Microsoft Academic Search

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

Gerald Estrin

1960-01-01

354

Perishable inventory systems with variable input and demand rates  

Microsoft Academic Search

We consider a certain class of perishable inventory systems with items and demands arriving at random times. The shelf lifetime of every item is finite and deterministic. Every demand is for a single item and is satisfied by the oldest item on the shelf, if available. Generalizing previous work, we assume that the input and\\/or the demand rate depend on

Steven Nahmias; David Perry; Wolfgang Stadje

2004-01-01

355

Design of Adaptive Variable Structure Control System for Aerospace Vehicle  

Microsoft Academic Search

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

Tong Chunxia

2006-01-01

356

Raman Scattering Studies of Variably Ordered Cluster Systems  

NASA Astrophysics Data System (ADS)

In-situ, ultrahigh vacuum Raman scattering was used to study the vibrational properties of bismuth (Bi) clusters and alkali-metal doped C_{60 } films. Optical interference enhancement methods and multichannel detection were utilized to obtain detectable signals from clustered films of several monolayers equivalent thickness. Evidence for a structural transition in Bi clusters was observed with decreasing film thickness from a bulk-derived nanocrystalline to an amorphous phase. This new amorphous cluster phase differed from that of bulk amorphous bismuth, which is metallic, in that these small clusters appeared to have semiconducting character. The size distributions of Bi clusters at different equivalent film thicknesses have been studied using transmission electron microscopy. These measurements revealed the presence of growth coalescence processes with increasing film thickness, as well as cluster mobility phenomena upon adsorption of atomic hydrogen. Both growth and mobility coalescence have been suggested to drive the transition from amorphous to nanocrystalline clusters. The effects of alkali-metal doping on the Raman spectrum of C_{60} films was also studied. Changes in phonon frequencies and linewidths with variations in film thickness, dopant type, stoichiometry, and temperature revealed electron-phonon coupling and disorder effects. The strong damping of both low and high frequency phonons was shown to be consistent with the observed superconducting behavior in K_3C_{60 } and Rb_3C_ {60}. Weaker, disorder-related damping was seen in non-superconducting Na_3C _{60}. Intermolecular phonon and variable temperature studies suggested the importance of alkali-metal site occupancy disorder for the lack of superconductivity in Na_3C_{60}. Similar electron-phonon damping effects to those in K_3C_{60} and Rb _3C_{60} were observed in Na_3C_{60} at high temperature, implying a transition to a metallic state.

Mitch, Michael George

357

Orbits and masses in the multiple system LHS 1070  

NASA Astrophysics Data System (ADS)

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

Köhler, R.; Ratzka, T.; Leinert, Ch.

2012-05-01

358

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

SciTech Connect

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

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

2009-01-01

359

The Formal Elements Art Therapy Scale: A Measurement System for Global Variables in Art  

Microsoft Academic Search

The Formal Elements Art Therapy Scale (FEATS) is a measurement system for applying numbers to global variables in two-dimensional art (drawing and painting). While it was originally developed for use with the single-picture assessment (\\

Linda M. Gantt; Frances Anderson

2009-01-01

360

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

361

Design and control of a variable-speed generator system for a WECS (wind energy conversion system)  

SciTech Connect

Sandia National Laboratories has been funded by the Wind/Ocean Technologies Division of the DOE to design and build a 34-meter diameter VAWT research Test Bed incorporating a constant frequency, variable speed generator system (VSGS). The turbine will be utilized to evaluate aerodynamic and structural dynamic technological advances and to develop and test variable speed control algorithms. These algorithms are intended to control the power output and increase the turbine fatigue life. The paper will discuss the design of the power system, VSGS and the control system hardware. The variable speed control algorithm development to date is also discussed. 6 refs., 5 figs.

Ralph, M.E.

1987-01-01

362

PORFLO-3: A mathematical model for fluid flow, heat, and mass transport in variably saturated geologic media. Users manual, Version 1.2  

Microsoft Academic Search

This manual provides instructions for the use of the PORFLO-3 computer code. This computer code is based on mathematical formulation of fluid flow, heat transfer, and mass transport in variably saturated geologic media. The geologic medium may be heterogeneous and anisotropic and may contain linear and planar features such as boreholes and fractures. The code can be used to analyze

A. K. Runchal; B. Sagar; N. W. Kline

1992-01-01

363

PORFLO-3: A mathematical model for fluid flow, heat, and mass transport in variably saturated geologic media: Users manual, version 1.0  

Microsoft Academic Search

This manual provides instructions for the use of the PORFLO-3 computer code. This computer code is based on mathematical formulation of fluid flow, heat transfer, and mass transport in variably saturated geologic media. The geologic medium may be heterogeneous and anisotropic and may contain linear and planar features such as boreholes and fractures. The code can be used to analyze

A. K. Runchal; B. Sagar

1989-01-01

364

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...

365

Enhanced Recovery Utilizing Variable Frequency Drives and a Distributed Power System  

SciTech Connect

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

Randy Peden; Sanjiv Shah

2005-07-26

366

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

367

Accelerator mass spectrometry with a coupled tandem-linac system  

SciTech Connect

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

Kutschera, W.

1984-01-01

368

On Power Quality of Variable-Speed Constant-Frequency Aircraft Electric Power Systems  

Microsoft Academic Search

In this paper, a comprehensive model of the variable-speed constant-frequency aircraft electric power system is developed to study the performance characteristics of the system and, in particular, the system power quality over a frequency range of operation of 400 Hz to 800 Hz. A fully controlled active power filter is designed to regulate the load terminal voltage, eliminate harmonics, correct

Ahmad Eid; Hassan El-Kishky; Mazen Abdel-Salam; Mohamed T. El-Mohandes

2010-01-01

369

BP neural network prediction-based variable-period sampling approach for networked control systems  

Microsoft Academic Search

The biggest problem that networked control systems face is the random time-varying delay, which often causes system instability and even collapse. Aiming at this problem, a new modeling scheme for the networked control systems, motivated from a variable-period sampling approach, is presented in this paper. Here, the time delay to occur at current sampling step is taken as the sampling

Jianqiang Yi; Qian Wang; Dongbin Zhao; John T. Wen

2007-01-01

370

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

371

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

372

The pulsation, temperatures and metallicities of Mira and semiregular variables in different stellar systems  

NASA Astrophysics Data System (ADS)

Data on angular diameters and infrared photometry for late-type stars are assembled. It is shown that a consistent T_eff scale can be established, combining results for Mira and non-Mira M-type stars. The log T_eff versus (J-K) relation is much steeper than previously adopted, but is consistent with predictions from model stellar atmospheres. Comparison of the linear diameters of Miras measured in the red spectral region with those measured in the infrared shows that models successfully predict the extension observed in the red, and the combined data provide strong evidence that Miras are pulsating in their first overtone. Data on Miras and semiregular (SR) variables in globular clusters are compared with predictions from stellar evolution and pulsation theory. These data also support a steep log T_eff versus (J-K) relation at low temperatures. The Miras and SR variables in 47 Tuc conform to theoretical expectation if they are undergoing an average mass loss of ~3x10^-7 M_ yr^-1. SR variables in both metal-rich and metal-poor globular clusters are probably pulsating, like the Miras in their first overtone. The general agreement between observations and theory now found suggests that infrared colour-period relations can be used to investigate overall metallicity differences between Miras in different stellar systems, at least at the shorter periods where circumstellar extinction is probably negligible. A comparison of Miras in Galactic globular clusters of known metallicity with those in the LMC and in the SgrI window of the Galactic Bulge indicates that Miras of periods 100 to 300d in the LMC have a mean metallicity log z~-0.6, whilst those in SgrI have log z~-0.2, close to that of K giants in the NGC 6522 Bulge window. No evidence has yet been found for a dependence of the Mira period-luminosity relation on metallicity, and it is pointed out that theory does not at present give a definitive prediction of such an effect. Some stars of special interest are discussed in an appendix.

Feast, M. W.

1996-01-01

373

Mask inspection system with variable sensitivity and printability verification function  

NASA Astrophysics Data System (ADS)

We report on the development of a new mask inspection technology that makes total inspection faster and less costly. The new technology adopts a method of selecting a defect detection sensitivity level for every local area, defined by factors such as defect judgment algorithm and defect judgment threshold. This approach results in a reduction of pseudodefect count leading to shorter inspection and review time. Selected defect detection sensitivity levels for every local area are extracted from a database of Mask Data Rank (MDR) that is based on the design intent from the design stage, and/or on a pre-analysis of inspection pattern data. The proposed system also executes a printability verification function, not only for the mask defect regions but also for specific portions where high Mask Error Enhancement Factor (MEEF) is determined. It is necessary to ascertain suppression of pseudo-defect detection for extremely complicated masks such as masks with Source-Mask Optimization (SMO). This work reports on the new mask inspection system.

Inoue, Takafumi; Takahara, Kenichi; Tsuchiya, Hideo; Tokita, Masakazu; Inoue, Tadao; Yamabe, Masaki

2010-04-01

374

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

375

Three-dimensional display system using a variable parallax barrier and eye tracking  

NASA Astrophysics Data System (ADS)

In this paper, we propose an eye tracking system using a variable parallax barrier capable of providing the utmost natural stereo images. The variable parallax barrier consists of four sub-barriers, and a new cross connector composed of 640 lines flexible-printed-circuit is designed to create a sub-barrier. A depth camera based on the time-of-flight theory is utilized to implement an eye tracking system for an observer. The variable parallax barrier located in front of a monitor will be operated and controlled electrically through serial communication according to the values of coordinates gained by the camera. We compared the performance of the variable parallax barrier with that of other general systems via computer simulation.

Chae, Ho-Byung; You, Young-Rok; Kwon, Soon-Chul; Lee, Seung-Hyun

2011-08-01

376

Algebraic approach for the reconstruction of Rossler system from the x(3)- variable  

NASA Astrophysics Data System (ADS)

In this paper we propose a simple method to identify the unknown parameters and to estimate the underlying variables from a given chaotic time series {x(3)(t(k)) (k=n)(0) of the three-dimensional Rossler system (RS). The reconstruction of the RS from its x(3-) variable is known to be considerably more difficult than reconstruction from its two other variables. We show that the system is observable and algebraically identifiable with respect to the auxiliary output In(x(3)), hence, a differential parameterization of the output and its time derivatives can be obtained. Based on these facts, we proceed to form an extended re-parameterized system (linear-in-the -parameters), which turns out to be invertible, allowing us to estimate the variables and missing parameters.

Ibanez, C. A.

2006-02-01

377

The distribution of mass and angular momentum in the solar system  

SciTech Connect

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

Marochnik, L.S.; Mukhin, L.M.; Sagdeev, R.Z. (Institute for Space Research, USSR Academy of Sciences, Moscow (SU))

1989-01-01

378

Variable cycle stirling engine and gas leakage control system therefor  

SciTech Connect

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

Otters, J.

1984-12-25

379

Cold Mass Support System for he D0 Solenoid  

SciTech Connect

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

Squires, B.; /Fermilab

1993-08-09

380

An SB1 with a Brown Dwarf Component in a Very-Low Mass Triple System  

NASA Astrophysics Data System (ADS)

We report the identification of the M9 dwarf SDSS J000649.16-085246.3 as part of a tightly-separated brown dwarf binary within a low-mass triple system with the M7 star LP 704-48 as a widely-separated ( 600 AU) third component. Low-resolution spectral data from IRTF/SpeX show subtle spectral features typical of a T dwarf companion, and spectral template fitting indicates component types of M8.5 and T5±1 for the tight binary. Multi-epoch high-resolution spectra from Keck/NIRSPEC, taken over 16 months, show RV variability with an amplitude of 9 km/s, and orbital fits reveal a nearly circular orbit with a period of 150 days and semi-major axis of 0.2 AU. The absence of H alpha emission in the M7 primary suggests a minimum age of 7 Gyr, which with the radial velocity orbit provides stringent constraints on the masses of SDSS J000649.16-085246.3A and B. Hierarchical multiple systems like this one provide an ideal benchmark for the study of brown dwarf formation.

Bardalez Gagliuffi, Daniella; Burgasser, A. J.; Luk, C.; Prato, L.; Dhital, S.; Nicholls, C.; West, A. A.; Melis, C.; Lepine, S.

2012-05-01

381

Advanced Mass Spectrometer.  

National Technical Information Service (NTIS)

The Advanced Mass Spectrometer (AMS) is a state-of-the-art ion microprobe with fine primary ion beam focus and a unique mass spectrometer. A variable inhomogeneity magnet system, with 288 detectors, all serviced by computer data handling, provides the hea...

F. Halliday J. D. Stein

1977-01-01

382

Simulation of Variable Speed Wind Generation System Using Boost Converter of Permanent Magnet Synchronous Generator  

NASA Astrophysics Data System (ADS)

This paper proposes variable-speed wind generation system using the boost converter. The proposed system has three speed control modes for the wind velocity. The control mode of low wind velocity regulates the armature current of the generator with the boost converter to control the speed of wind turbine. The control mode of middle wind velocity regulates the DC link voltage with the vector controlled inverter to control the speed of wind turbine. The control mode of high wind velocity regulates the pitch angle of the wind turbine with the pitch angle control system to control the speed of wind turbine. The hybrid of three control modes extends the variable-speed range. The proposed system simplifies the maintenance and improves the reliability and reduces the cost in compare with the variable-speed wind generation system using PWM converter. This paper describes the control strategy and modeling for simulation using Matlab Simulink of the proposed system. Also this paper describes the control strategy and modeling of variable-speed wind generation system using PWM converter. The steady state and transient responses for wind velocity changes are simulated using the Matlab Simulink. This paper verifies the fundamental performance of the system using boost converter by discussing the simulation results of the both systems.

Ohyama, Kazuhiro; Sakamoto, Tsuyoshi; Arinaga, Shinji; Yamashita, Yukio

383

Reco level Smin and subsystem Smin: improved global inclusive variables for measuring the new physics mass scale in MET events at hadron colliders  

SciTech Connect

The variable {radical}s{sub min} was originally proposed in [1] as a model-independent, global and fully inclusive measure of the new physics mass scale in missing energy events at hadron colliders. In the original incarnation of {radical}s{sub min}, however, the connection to the new physics mass scale was blurred by the effects of the underlying event, most notably initial state radiation and multiple parton interactions. In this paper we advertize two improved variants of the {radical}s{sub min} variable, which overcome this problem. First we show that by evaluating the {radical}s{sub min} variable at the RECO level, in terms of the reconstructed objects in the event, the effects from the underlying event are significantly diminished and the nice correlation between the peak in the {radical}s{sub min}{sup (reco)} distribution and the new physics mass scale is restored. Secondly, the underlying event problem can be avoided altogether when the {radical}s{sub min} concept is applied to a subsystem of the event which does not involve any QCD jets. We supply an analytic formula for the resulting subsystem {radical}s{sub min}{sup (sub)} variable and show that its peak exhibits the usual correlation with the mass scale of the particles produced in the subsystem. Finally, we contrast {radical}s{sub min} to other popular inclusive variables such as H{sub T}, M{sub Tgen} and M{sub TTgen}. We illustrate our discussion with several examples from supersymmetry, and with dilepton events from top quark pair production.

Konar, Partha; /Florida U.; Kong, Kyoungchul; /SLAC; Matchev, Konstantin T.; Park, Myeonghun; /Florida U.

2011-08-11

384

Dynamical variable structure controller for power regulation of wind energy conversion systems  

Microsoft Academic Search

The paper addresses the problem of output power regulation of fixed-pitch variable-speed wind energy conversion systems. Operation is constrained by practical reasons to the low-speed side of the turbine power-speed curve. Unfortunately, this region is characterized by a nonminimum phase dynamics which is an obstacle to perform the regulation task. A dynamical variable structure controller is developed that accomplishes the

Hernán De Battista; Ricardo J. Mantz

2004-01-01

385

Three-dimensional display system using a variable parallax barrier and eye tracking  

Microsoft Academic Search

In this paper, we propose an eye tracking system using a variable parallax barrier capable of providing the utmost natural stereo images. The variable parallax barrier consists of four sub-barriers, and a new cross connector composed of 640 lines flexible-printed-circuit is designed to create a sub-barrier. A depth camera based on the time-of-flight theory is utilized to implement an eye

Ho-Byung Chae; Young-Rok You; Soon-Chul Kwon; Seung-Hyun Lee

2011-01-01

386

Interacting Compact Binaries: Modeling Mass Transfer in Eccentric Systems  

NASA Astrophysics Data System (ADS)

We discuss mass transfer in eccentric binaries containing a white dwarf and a neutron star (WD-NS binaries). We show that such binaries are produced from field binaries following a series of mass transfer episodes that allow the white dwarf to form before the neutron star. We predict the orbital properties of binaries similar to the observed WD-NS binary J1141+6545, and show that they will undergo episodic mass transfer from the white dwarf to the neutron star. Furthermore, we describe oil-on-water, a two-phase SPH formalism that we have developed in order to model mass transfer in such binaries.

Church, R. P.; Davies, M. B.; Bobrick, A.; Tout, C. A.

2012-07-01

387

Power Maximization Control of Variable Speed Wind Generation System Using Permanent Magnet Synchronous Generator  

Microsoft Academic Search

This paper proposes the sensorless output power maximization control of the wind generation system. A permanent magnet synchronous generator (PMSG) is used as a variable speed generator in the proposed system. The generator torque is suitably controlled according to the generator speed and thus the power from a wind turbine settles down on the maximum power point by the proposed

Shigeo Morimoto; Tomohiko Nakamura; Yoji Takeda

2003-01-01

388

Simulation of Variable Speed Wind Generation System Using Boost Converter of Permanent Magnet Synchronous Generator  

Microsoft Academic Search

This paper proposes variable-speed wind generation system using the boost converter. The proposed system has three speed control modes for the wind velocity. The control mode of low wind velocity regulates the armature current of the generator with the boost converter to control the speed of wind turbine. The control mode of middle wind velocity regulates the DC link voltage

Kazuhiro Ohyama; Tsuyoshi Sakamoto; Shinji Arinaga; Yukio Yamashita

2008-01-01

389

State variable integration in SOA Energy Management System for building air-conditioners  

Microsoft Academic Search

Advancement of Energy Management Systems (EMSs) for building facilities is becoming more important for sustainable development. The Service Oriented Architecture (SOA) will be a powerful approach for these systems. Distributed type building air-conditioners, which are dominant in Japan, have many distributed raw state variables required by an EMS. This makes it difficult to apply the SOA to those EMSs. We

Chuzo Ninagawa; Tomotaka Sato

2010-01-01

390

Improving Flow Response of a Variable-rate Aerial Application System by Interactive Refinement  

Technology Transfer Automated Retrieval System (TEKTRAN)

Experiments were conducted to evaluate response of a variable-rate aerial application controller to changing flow rates and to improve its response at correspondingly varying system pressures. System improvements have been made by refinement of the control algorithms over time in collaboration with ...

391

Heating control strategy in fresh air processor matched with variable refrigerant flow air conditioning system  

Microsoft Academic Search

The fresh air processor (FAP), matched with the variable refrigerant flow air conditioning system (VRF AC), has been developed. Two control methods were adopted to control the system running and air outlet temperature, contrastively. The first method is that the running frequency in heating mode is adjusted in terms of the ordinary control method of VRF, i.e., constant condensation temperature.

Qiu Tu; Shoubo Mao; Yuhai Feng; Defang Guo

2011-01-01

392

Molecular basis of immunoglobulin variable region gene usage in systemic autoimmunity  

Microsoft Academic Search

This review focuses on the immunoglobulin variable region (IgV) chain gene usage in patients with systemic autoimmune diseases, with particular emphasis on systemic lupus erythematosus (SLE), a condition known to be associated with the production of a number of characteristic autoantibodies as an abnormality. The IgV repertoire is shaped by a variety of molecular and selective influences that are difficult

T. Dörner; P. E. Lipsky

2005-01-01

393

FUZZY LOGIC BASED INTELLIGENT CONTROL OF A VARIABLE SPEED CAGE MACHINE WIND GENERATION SYSTEM  

EPA Science Inventory

The paper describes a variable-speed wind generation system where fuzzy logic principles are used to optimize efficiency and enhance performance control. A squirrel cage induction generator feeds the power to a double-sided pulse width modulated converter system which either pump...

394

Fuzzy logic control of variable speed induction machine wind generation system  

Microsoft Academic Search

This paper presents the use of fuzzy logic control (FLC) of a variable speed induction machine wind generation system. The generation system uses three fuzzy logic controllers (FLC's), first fuzzy logic controller tracks the generator speed with wind velocity to extract maximum power. Second fuzzy logic controller programs the machine flux for light load efficiency improvement. Third fuzzy logic controller

M. K. K. Reddy; G. Sreenivasulu

2010-01-01

395

Design and Practical Implementation of a Novel Variable-Speed Generation System  

Microsoft Academic Search

This paper investigates a novel variable-speed gener- ation system. A new integrated power circuit with voltage clamp protection and self-excitation function is presented. Convention- ally, due to the large internal impedance of a generator, oscillations are produced by the resonances of the filter in armature currents which may cause unstable behavior of the generation system. In this paper, an active

Mingming Shi; Bo Zhou; Jiadan Wei; Zhuoran Zhang; Yiran Mao; Chu Han

2011-01-01

396

Mobile sample holder applying multiple heating systems with a variable heating and cooling rate  

Microsoft Academic Search

A mobile sample holder applying multiple heating systems with variable heating and cooling opportunities will be presented. Design details and initial results will be given. The whole sample holder system consists of two units: the docking station (one) on which the mobile sample holder together with its mobile sample plate (two) is mounted. Some of the significant advantages of this

U. Leist; A. Winkler; J. Büssow; K. Al-Shamery

2003-01-01

397

An intelligent maximum power extraction algorithm for inverter-based variable speed wind turbine systems  

Microsoft Academic Search

This paper focuses on the development of maximum wind power extraction algorithms for inverter-based variable speed wind power generation systems. A review of existing maximum wind power extraction algorithms is presented in this paper, based on which an intelligent maximum power extraction algorithm is developed by the authors to improve the system performance and to facilitate the control implementation. As

Quincy Wang; Liuchen Chang

2004-01-01

398

An extended model of design process of lean production systems by means of process variables  

Microsoft Academic Search

In this paper, we present an axiomatic modeling of lean production system design, using process variables (PVs). So far, we had developed a model for conceptual design of lean production systems by means of FR–DP relationships, the key characteristics of axiomatic design (AD) methodology, appeared in the proceedings of Second International Conference of Axiomatic Design. Albeit the model in question

Mahmoud Houshmand; Bizhan Jamshidnezhad

2006-01-01

399

A flexible active and reactive power control strategy for a variable speed constant frequency generating system  

Microsoft Academic Search

Variable-speed constant-frequency generating systems are used in wind power, hydroelectric power, aerospace, and naval power generation applications to enhance efficiency and reduce friction. In these applications, an attractive candidate is the slip power recovery system comprising a doubly excited induction machine or doubly excited brushless reluctance machine and PWM power converters with a DC link. In this paper, a flexible

Yifan Tang; Longya Xu

1995-01-01

400

Bottleneck Analysis For Computer And Communication Systems With Workload Variabilities & Uncertainties  

Microsoft Academic Search

. Bottleneck analysis using queueing network models is an important technique for the performanceanalysis and capacity planning of computer and communication systems. Conventional singleclass as well as multiclass queueing network models use single mean values as input parameters. However,uncertainties and variabilities in service demands may exist in many types of systems. Using models witha single aggregate mean value for each

J. Lüthi; G. Haring

1997-01-01

401

Steps Toward Accommodating Variable Position Tracking Accuracy in a Mobile Augmented Reality System  

Microsoft Academic Search

The position-tracking accuracy of a location-aware mobile system can change dynamically as a function of the user's location and other variables specific to the tracker technology used. This is especially problematic for mobile augmented reality systems, which ideally require extremely precise position tracking for the user's head, but which may not always be able to achieve the necessary level of

Tobias Hollerer; Drexel Hallaway; Navdeep Tinna

2001-01-01

402

The Study of Resonant Variability Observed in the Massive LMC System BI 108  

NASA Astrophysics Data System (ADS)

The LMC star BI 108 is photometrically variable with the unique light curve: Two strong periods are present in a strict 3:2 resonance, staying coherent over several observing seasons. A spectroscopic data collected at VLT/UVES reveals unexpected and still not fully understood behavior of the system, that has not been observed in any other early-type multiple systems.

Ko?aczkowski, Z.; Mennickent, R.; Rivinius, T.

2010-12-01

403

Transient stability margin of variable versus fixed speed wind systems in electrical grids  

Microsoft Academic Search

For networks with large scale integration of wind farms this paper demonstrates a significant difference between the transient behavior of variable speed wind systems that adopt doubly fed induction generators with a four quadrant ac-to-ac converter connected to the rotor windings (DFIG) and a fixed speed wind system, where the conventional cage induction generator is used. The reason for this

M. V. A. Nunes; U. H. Bezerra; H. H. Zurn

2003-01-01

404

Modeling and experimental evaluation of an automotive air conditioning system with a variable capacity compressor  

Microsoft Academic Search

A steady state computer simulation model has been developed for refrigeration circuits of automobile air conditioning systems. The simulation model includes a variable capacity compressor and a thermostatic expansion valve in addition to the evaporator and micro channel parallel flow condenser. An experimental bench made up of original components from the air conditioning system of a compact passenger vehicle has

J. M. Saiz Jabardo; W. Gonzales Mamani; M. R. Ianella

2002-01-01

405

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

Microsoft Academic Search

Acceleration of liquid chromatography\\/mass spectrometric (LC\\/MS) analysis for metabolite identi- fication critically relies on effective data processing since the rate of data acquisition is much faster than the rate of data mining. The rapid and accurate identification of metabolite peaks from complex LC\\/MS data is a key component to speeding up the process. Current approaches routinely use selected ion chromatograms

Ming Gu; Yongdong Wang; Xian-guo Zhao; Zhe-Ming Gu

2006-01-01

406

Similarity evaluation between query and retrieved masses using a content-based image retrieval (CBIR) CADx system for characterization of breast masses on ultrasound images: an observer study  

Microsoft Academic Search

The purpose of this study is to evaluate the similarity between the query and retrieved masses by a Content-Based Image Retrieval (CBIR) computer-aided diagnosis (CADx) system for characterization of breast masses on ultrasound (US) images based on radiologists' visual similarity assessment. We are developing a CADx system to assist radiologists in characterizing masses on US images. The CADx system retrieves

Hyun-Chong Cho; Lubomir Hadjiiski; Berkman Sahiner; Heang-Ping Chan; Mark Helvie; Alexis V. Nees; Chintana Paramagul

2011-01-01

407

Development of a multicomponent film diffusion controlled mixed bed ion exchange column model applicable to variable influent systems  

NASA Astrophysics Data System (ADS)

Scope and method of study. The purpose of this study was to develop a generalized rate model to handle multicomponent mixed-bed ion exchange (MBIE) with multivalent dissociative species and variable influent conditions. To achieve this goal, mass transfer mechanisms of weak electrolytes in ion exchange column have been studied; and based on which, rate expressions for weak electrolyte transfer have been proposed. In addition, the column material balance has been derived in terms of the constituent species concentrations only. Finally, generalized dissociation equilibrium equations for several types of weak electrolyte constituents were implemented, and the effluent concentrations were determined by solving column material balance equations along with the rate expressions. Findings and conclusions. The mixed bed ion exchange column model has been successfully programmed into a computer program and is capable of predicting the effluent concentration histories, dynamic resin loading, solution, and rate profiles. The column material balance has been satisfied to within 1% for all chemistries studied. The model is capable of simulating variable influent contaminant concentrations and flow rates by sequentially using the loading profiles of previous simulations. The model maintains electroneutrality at all times. Dissociative species transfer is adequate for many systems, but additional work is required to incorporate molecular constituent mass transfer.

Hussey, Dennis Frank

2000-10-01

408

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

NASA Astrophysics Data System (ADS)

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

Strecker, M. R.; Bookhagen, B.

2010-12-01

409

Doing more with less: a method for low total mass, affinity measurement using variable-length nanotethers.  

PubMed

Interactions between biomolecules are an important feature of biological systems and understanding these interactions is a key goal in biochemical studies. Using conventional techniques, such as surface plasmon resonance and isothermal titration calorimetry, the determination of the binding constants requires a significant amount of time and resources to produce and purify sufficient quantities of biomolecules in order to measure the affinity of biological interactions. Using DNA hybridization, we have demonstrated a new technique based on the use of nanotethers and time-resolved Forster resonance energy transfer (FRET) that significantly reduces the amount of material required to carry out quantitative binding assays. Test biomolecules were colocalized and attached to a surface using DNA tethers constructed from overlapping oligonucleotides. The length of the tethers defines the concentration of the tethered biomolecule. Effective end concentrations ranging from 56 nM to 3.8 ?M were demonstrated. The use of variable length tethers may have wider applications in the quantitative measurement of affinity binding parameters. PMID:22029261

Perrins, Richard D; Orchard, Craig; Zavodszky, Maria; Kasry, Amal; Nikolaev, Nikolay; Harwood, Adrian; Borri, Paola; Dale, Trevor

2011-11-08

410

A method for separating Antarctic postglacial rebound and ice mass balance using future ICESat Geoscience Laser Altimeter System, Gravity Recovery and Climate Experiment, and GPS satellite data  

Microsoft Academic Search

Measurements of ice elevation from the Geoscience Laser Altimeter System (GLAS) aboard the Ice, Cloud, and Land Elevation Satellite can be combined with time-variable geoid measurements from the Gravity Recovery and Climate Experiment (GRACE) satellite mission to learn about ongoing changes in polar ice mass and viscoelastic rebound of the lithosphere under the ice sheet. We estimate the accuracy in

Isabella Velicogna; John Wahr

2002-01-01

411

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

NASA Astrophysics Data System (ADS)

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

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

412

SUPER-KEPLERIAN FREQUENCIES IN ACCRETION DISKS. IMPLICATIONS FOR MASS AND SPIN MEASUREMENTS OF COMPACT OBJECTS FROM X-RAY VARIABILITY STUDIES  

SciTech Connect

The detection of fast quasi-periodic variability from accreting black holes and neutron stars has been used to constrain their masses, radii, and spins. If the observed oscillations are linear modes in the accretion disks, then bounds can be placed on the properties of the central objects by assuming that these modes are locally sub-Keplerian. If, on the other hand, the observed oscillations correspond to nonlinear resonances between disk modes, then the properties of the central objects can be measured by assuming that the resonant modes are excited at the same radial annulus in the disk. In this paper, we use numerical simulations of vertically integrated, axisymmetric hydrodynamic accretion disks to provide examples of situations in which the assumptions implicit in both methods are not satisfied. We then discuss our results for the robustness of the mass and spin measurements of compact objects from variability studies.

Mao, S. A. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Psaltis, Dimitrios; Milsom, John A., E-mail: samao@cfa.harvard.ed [Physics Department, University of Arizona, Tucson, AZ 85721 (United States)

2009-09-20

413

The Effects of Post-Main-Sequence Solar Mass Loss on the Stabilityof Our Planetary System  

Microsoft Academic Search

We present the results of extensive long-term integrations of systems of planets with orbits initially identical to subsets of the planets within our Solar System, but with the Sun's mass decreased relative to the masses of the planets. For systems based on the giant planets, we find an approximate power-law correlation between the time elapsed until a pair of planetary

Martin J. Duncan; Jack J. Lissauer

1998-01-01

414

Dynamic load change stress minimizing control of elastically coupled multi-mass systems  

Microsoft Academic Search

Elastically coupled multi-mass systems are found in many industrial applications, like wind energy plants or in robotics. Dynamic load changes often cause peaks in the shaft torsion torque and result in damages to the system. This paper presents a control strategy to reduce the dynamic loads on the drive train and the stress in wind turbines and other multi-mass systems,

Matthias Joost; Christian Mehler; Bernd Orlik

2010-01-01

415

The variable mass loss of the AGB star WX Piscium as traced by the CO J = 1-0 through 7-6 lines and the dust emission  

NASA Astrophysics Data System (ADS)

Context: Low and intermediate mass stars lose a significant fraction of their mass through a dust-driven wind during the Asymptotic Giant Branch (AGB) phase. Recent studies show that winds from late-type stars are far from being smooth. Mass-loss variations occur on different time scales, from years to tens of thousands of years. The variations appear to be particularly prominent towards the end of the AGB evolution. The occurrence, amplitude and time scale of these variations are still not well understood. Aims: The goal of our study is to gain insight into the structure of the circumstellar envelope (CSE) of WX Psc and map the possible variability of the late-AGB mass-loss phenomenon. Methods: We have performed an in-depth analysis of the extreme infrared AGB star WX Psc by modeling (1) the CO J = 1-0 through 7-6 rotational line profiles and the full spectral energy distribution (SED) ranging from 0.7 to 1300 ?m. We hence are able to trace a geometrically extended region of the CSE. Results: Both mass-loss diagnostics bear evidence of the occurrence of mass-loss modulations during the last 2000 yr. In particular, WX Psc went through a high mass-loss phase (dot{M} ˜ 5 × 10-5 M?/yr) some 800 yr ago. This phase lasted about 600 yr and was followed by a long period of low mass loss (dot{M} ˜ 5 × 10-8 M?/yr). The present day mass-loss rate is estimated to be 6 × 10-6 M?/yr. Conclusions: The AGB star WX Psc has undergone strong mass-loss rate variability on a time scale of several hundred years during the last few thousand years. These variations are traced in the strength and profile of the CO rotational lines and in the SED. We have consistently simulated the behaviour of both tracers using radiative transfer codes that allow for non-constant mass-loss rates.

Decin, L.; Hony, S.; de Koter, A.; Molenberghs, G.; Dehaes, S.; Markwick-Kemper, F.

2007-11-01

416

An adaptive variable gain control for a novel pneumatic position servo system  

Microsoft Academic Search

A novel pneumatic position servo system is described, in which an electro-pneumatic converter is a 2-way-3-port electro-pneumatic pressure valve. On the basis of analyzing and studying the pneumatic position servo system, a new control method which improves the system performances by means of an adaptive variable gain optimal control is presented for the weak point of the pneumatic position servo

Li Baoren; Xu Yaoming

1994-01-01

417

Design and performance evaluation of a fuzzy-logic-based variable-speed wind generation system  

Microsoft Academic Search

Artificial intelligence techniques, such as fuzzy logic, neural networks and genetic algorithms, have recently shown promise in the application of power electronic systems. The paper describes the control strategy development, design and experimental performance evaluation of a fuzzy logic-based variable-speed wind generation system that uses a cage-type induction generator and double-sided PWM power converters. The system can feed a utility

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

1997-01-01

418

Experimental evaluation of a variable-speed, doubly-fed wind-power generation system  

Microsoft Academic Search

The paper evaluates the potential of a brushless doubly-fed generation system for wind power applications. A 1.5 kW proof-of-concept laboratory prototype is used to investigate the feasibility of the proposed variable-speed generation principle. Experimental results show that the prototype system can achieve high efficiency over a range of speeds. The system efficiencies achieved at the power levels considered compare favorably

Chris S. Brune; R. Spee; A. K. Wallace

1994-01-01

419

Experimental evaluation of a variable-speed, doubly-fed wind-power generation system  

Microsoft Academic Search

The authors evaluate the potential of a brushless doubly fed generation system for wind power applications. A 1.5 kW proof-of-concept laboratory prototype is used to investigate the feasibility of the proposed variable-speed generation principle. Experimental results show that the prototype system can achieve high efficiency over a range of speeds. The system efficiencies achieved at the power levels considered compare

C. Brune; R. Spe; A. K. Wallace

1993-01-01

420

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

Microsoft Academic Search

The paper presents numerical calculations simulating the evolution of low-mass, interacting close binary systems in which mass-exchange is started from a 1.0-2.0 solar mass-losing component towards an accreting compact companion. The range of initial periods of these systems has been chosen to: (1) result in the capture of the system by angular momentum losses, and (2) cover a large part

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

1989-01-01

421

PREPROCESSING, VARIABLE SELECTION AND CLASSIFICATION RULES IN THE APPLICATION OF SIMCA PATTERN RECOGNITION TO MASS SPECTRAL DATA  

EPA Science Inventory

In a recent report a strategy was proposed for the classification and identification of toxic organic compounds observed in ambient air from mass spectra using computational pattern recognition based on SlMCA principal components modeling of the autocorrelation transformed mass s...

422

SST subseasonal variability in the Benguela upwelling system from satellite observations  

NASA Astrophysics Data System (ADS)

Subseasonal variability of sea surface temperature (SST) in the Benguela upwelling system is investigated using TMI satellite derived data over the period 2000-2008. Spatio-temporal characteristics of subseasonal variability are documented based on Empirical Orthogonal Functions (EOF) decomposition and wavelet analysis. Two regimes of variability are evidenced: submonthly with a dominant 11-days oscillation and a lower frequency intraseasonal with a dominant 61-days oscillation. Both regimes are consistent with Ekman dynamics and are modulated, to a large extent, by the local surface wind stress. The seasonality of the relationship between wind stress and SST for submonthly (intraseasonal) regime is characterized by a marked semi-annual (seasonal) cycle, which is explained in terms of the impact of seasonal change of the ocean stratification on the vertical advection process. The wind-driven SST subseasonal variability is shown to be associated with eastward-propagating disturbance in the mid-latitudes. The results also suggest a role of the Antarctic Oscillation in modulating the intraseasonal upwelling variability. The characteristics of the equatorial intraseasonal Kelvin waves are documented in order to discuss possible impact of remote oceanic forcing on SST variability along the coast in the Benguela upwelling system.

Goubanova, Katerina; Illig, Séréna; Machu, Eric; Garçon, Véronique

2013-04-01

423

Mass-balance Approach to Interpreting Weathering Reactions in Watershed Systems  

Microsoft Academic Search

The mass-balance approach is conceptually simple and has found widespread applications in many fields over the years. For example, chemists use mass balance (Stumm and Morgan, 1996) to sum the various species containing an element in order to determine the total amount of that element in the system (free ion, complexes). Glaciologists use mass balance to determine the changes in

O. P. Bricker; B. F. Jones; C. J. Bowser

2003-01-01

424

Auto-positioning mount system for Stereoscopic imaging on variable distances  

NASA Astrophysics Data System (ADS)

This paper describes a stereo-imaging system for variable distances. The setup includes a mechanical mount system-holder, a control unit for the correct positioning of the cameras, the cameras itself and the object to capture. The goal of this setup was to achieve a true sense of scale and depth of the filmed material on dynamically variable distances to the object. This demands certain requirements which are usually not necessary for many applications of stereoscopic filming. In the last step, the resulting material is prepared for viewing.

Yordanov, Zh; Fuchs, E.; Löser, S.; Börcsök, J.

2012-05-01

425

MyNewsFlash: A System for Near Real-Time Variable Star Monitoring and Alerts  

NASA Astrophysics Data System (ADS)

MyNewsFlash is an automated and customizable system for distributing timely variable star data. It supplies near real-time reports to the user of the latest activity of a variable star or class of stars. The stars it monitors, the frequency of report delivery, the delivery format, and more features are all completely customizable so the reader receives only reports of information he or she wants and nothing more or less. In addition, manually-generated alerts called Special MyNewsFlashes are occasionally sent out with additional information on special or abnormal behavior of a variable star. MyNewsFlash evolved from the AAVSO News Flash, an electronic publication dedicated to outbursts of popular cataclysmic variable stars

Price, A.; Turner, R.; Malatesta, K.; Simonsen, M. A.

2004-12-01

426

Mass spectrum of the system of inhomogeneous intergalactic clouds.  

NASA Astrophysics Data System (ADS)

The possible influence of the internal structure of inter galactic clouds on their asymptotic mass spectrum n(m, t? ?) is investigated by numerically solving the Smoluchovski equation. Allowance for internal structure (inhomogeneity, fractality) leads to a relationship between cloud mass and radius of the type m oc Rk; values of the parameter k from the range [1.5, 3] were used in the calculations. Values of the slope q(k) of the asymptotic mass spectrum are obtained for different sections of the spectrum and different initial conditions n(m, t = 0). It is shown that the slope of the asymptotic spectrum depends strongly on the parameter k, which characterizes the degree of inhomogeneity of the mass distribution in the clouds. A self-consistent estimate of the fractal dimension of intergalactic clouds is obtained, improving the value found earlier.

Sokolov, A. S.

1997-10-01

427

Joint Modeling And Simulation System (J-MASS) personal computer station (JPC-station)  

Microsoft Academic Search

The concept and design approach for a J-MASS Personal Computer Station (JPC-Station) was developed on a Phase I Small Business Innovation Research (SBIR) Program with the Aeronautical Systems Center, Development Planning Directorate, J-MASS Program Office (ASC\\/XRJ). This paper describes the concept and top-level design for implementing the J-MASS Develop and Assemble modes on a PC to provide a dedicated J-MASS

G. L. Harris; M. L. Fricke

1996-01-01

428

Effective Masses for Donor Binding Energies in Quantum Well Systems  

NASA Astrophysics Data System (ADS)

The donor ionization energies in a quantum well and quantum dot with finite and infinite barriers are estimated for different well dimensions. Using the effective mass (EM) approximation, calculations are presented with constant effective mass and position dependent effective masses that are different for finite and infinite cases. Our results reduce to an approximate form used by X. H. Qi et al., Phys. Rev. B 58 (1998) 10578 in the finite barrier model and that of L. E. Oliveira and L. M. Falicov, Phys. Rev. B 34 (1986) 8676 in the infinite barrier case. Results are presented by taking the GaAs quantum well as an example. The use of constant effective mass of 0.067m0 is justified for well dimensions ?a* where a* is an effective Bohr radius which is about 100 Å. While Qi et al. found a maximum of 22% variation in the binding energies due to mass variation, we obtained nearly 100% variation when mass variations are included correctly.

Rajashabala, S.; Navaneethakrishnan, K.

429

Non-Markovian entanglement dynamics of quantum continuous variable systems in thermal environments  

SciTech Connect

We study two continuous variable systems (or two harmonic oscillators) and investigate their entanglement evolution under the influence of non-Markovian thermal environments. The continuous variable systems could be two modes of electromagnetic fields or two nanomechanical oscillators in the quantum domain. We use the quantum open system method to derive the non-Markovian master equations of the reduced density matrix for two different but related models of the continuous variable systems. The two models both consist of two interacting harmonic oscillators. In model A, each of the two oscillators is coupled to its own independent thermal reservoir, while in model B the two oscillators are coupled to a common reservoir. To quantify the degrees of entanglement for bipartite continuous variable systems in Gaussian states, logarithmic negativity is used. We find that the dynamics of the quantum entanglement is sensitive to the initial states, the oscillator-oscillator interaction, the oscillator-environment interaction and the coupling to a common bath or to different, independent baths.

Liu, K.-L.; Goan, H.-S. [Department of Physics and Center for Theoretical Sciences, National Taiwan University, Taipei, Taiwan (China) and National Center for Theoretical Sciences, Taipei 10617, Taiwan (China)

2007-08-15

430

Identification of a Wide, Low-Mass Multiple System Containing the Brown Dwarf 2MASS J0850359+105716  

NASA Astrophysics Data System (ADS)

We report our discovery of NLTT 20346 as an M5+M6 companion system to the tight binary (or triple) L dwarf 2MASS J0850359+105716. This nearby (~31 pc), widely separated (~7700 AU) quadruple system was identified through a cross-match of proper motion catalogs. Follow-up imaging and spectroscopy of NLTT 20346 revealed it to be a magnetically active M5+M6 binary with components separated by ~2'' (50-80 AU). Optical spectroscopy of the components shows only moderate H? emission corresponding to a statistical age of ~5-7 Gyr for both M dwarfs. However, NLTT 20346 is associated with the XMM-Newton source J085018.9+105644, and based on X-ray activity the age of NLTT 20346 is between 250 and 450 Myr. Strong Li absorption in the optical spectrum of 2MASS J0850+1057 indicates an upper age limit of 0.8-1.5 Gyr, favoring the younger age for the primary. Using evolutionary models in combination with an adopted system age of 0.25-1.5 Gyr indicates a total mass for 2MASS J0850+1057 of 0.07 ± 0.02 M sun, if it is a binary. NLTT 20346/2MASS J0850+1057 joins a growing list of hierarchical systems containing brown dwarf binaries and is among the lowest binding energy associations found in the field. Formation simulations via gravitational fragmentation of massive extended disks have successfully produced a specific analog to this system. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

Faherty, Jacqueline K.; Burgasser, Adam J.; Bochanski, John J.; Looper, Dagny L.; West, Andrew A.; van der Bliek, Nicole S.

2011-03-01

431

IDENTIFICATION OF A WIDE, LOW-MASS MULTIPLE SYSTEM CONTAINING THE BROWN DWARF 2MASS J0850359+105716  

SciTech Connect

We report our discovery of NLTT 20346 as an M5+M6 companion system to the tight binary (or triple) L dwarf 2MASS J0850359+105716. This nearby ({approx}31 pc), widely separated ({approx}7700 AU) quadruple system was identified through a cross-match of proper motion catalogs. Follow-up imaging and spectroscopy of NLTT 20346 revealed it to be a magnetically active M5+M6 binary with components separated by {approx}2'' (50-80 AU). Optical spectroscopy of the components shows only moderate H{alpha} emission corresponding to a statistical age of {approx}5-7 Gyr for both M dwarfs. However, NLTT 20346 is associated with the XMM-Newton source J085018.9+105644, and based on X-ray activity the age of NLTT 20346 is between 250 and 450 Myr. Strong Li absorption in the optical spectrum of 2MASS J0850+1057 indicates an upper age limit of 0.8-1.5 Gyr, favoring the younger age for the primary. Using evolutionary models in combination with an adopted system age of 0.25-1.5 Gyr indicates a total mass for 2MASS J0850+1057 of 0.07 {+-} 0.02 M{sub sun}, if it is a binary. NLTT 20346/2MASS J0850+1057 joins a growing list of hierarchical systems containing brown dwarf binaries and is among the lowest binding energy associations found in the field. Formation simulations via gravitational fragmentation of massive extended disks have successfully produced a specific analog to this system.

Faherty, Jacqueline K. [Department of Astrophysics, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10034 (United States); Burgasser, Adam J. [Center of Astrophysics and Space Sciences, Department of Physics, University of California, San Diego, CA 92093 (United States); Bochanski, John J. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Looper, Dagny L. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); West, Andrew A. [Department of Astronomy, Boston University, 725 Commonwealth Avenue Boston, MA 02215 (United States); Van der Bliek, Nicole S., E-mail: jfaherty@amnh.org [CTIO/National Optical Astronomy Observatory, Casilla 603, La Serena (Chile)

2011-03-15

432

Steady State Models of Ecological Systems: EcoPath Approach to Mass-Balanced System Descriptions  

Microsoft Academic Search

\\u000a We describe the fundamentals and applications of trophic models of ecological systems and show how a simple mass balance approach\\u000a of the early 1980s was further developed into a very advanced complex software package, freely available on the internet (Ecopath\\u000a with Ecosim, EwE, http:\\/\\/www.ecopath.org). Through its three decades of evolution, the approach became increasingly popular, with over three hundred Ecopath

Matthias Wolff; Marc Taylor

433

Family system dynamics and type 1 diabetic glycemic variability: a vector-auto-regressive model.  

PubMed

Statistical approaches rooted in econometric methodology, so far foreign to the psychiatric and psychological realms have provided exciting and substantial new insights into complex mind-body interactions over time and individuals. Over 120 days, this structured diary study explored the mutual interactions of emotions within a classic 3-person family system with its Type 1 diabetic adolescent's daily blood glucose variability. Glycemic variability was measured through daily standard deviations of blood glucose determinations (at least 3 per day). Emotions were captured individually utilizing the self-assessment manikin on affective valence (negative-positive), activation (calm-excited), and control (dominated-dominant). Auto- and cross-correlating the stationary absolute (level) values of the mutually interacting parallel time series data sets through vector autoregression (VAR, grounded in econometric theory) allowed for the formulation of 2 concordant models. Applying Cholesky Impulse Response Analysis at a 95% confidence interval, we provided evidence for an adolescent being happy, calm, and in control to exhibit less glycemic variability and hence diabetic derailment. A nondominating mother and a happy father seemed to also reduce glycemic variability. Random shocks increasing glycemic variability affected only the adolescent and her father: In 1 model, the male parent felt in charge; in the other, he calmed down while his daughter turned sad. All reactions to external shocks lasted for less than 4 full days. Extant literature on affect and glycemic variability in Type 1 diabetic adolescents as well as challenges arising from introducing econometric theory to the field were discussed. PMID:23795630

Günther, Moritz Philipp; Winker, Peter; Böttcher, Claudia; Brosig, Burkhard

2013-06-01

434

Simultaneous variable solutions of the incompressible steady Navier-Stokes equations in general curvilinear coordinate systems  

Microsoft Academic Search

The simultaneous variable solution technique of Bentson and Vradis (1987) for incompressible steady Navier-Stokes equations is extended to general curvilinear orthogonal and nonorthogonal coordinate systems. The formulation is fully second order accurate. Using this technique, flows in channels of different geometries were computed and the results were compared to available literature data. It is shown that the method is accurate,

G. Vradis; V. Zalak; J. Bentson

1992-01-01

435

A STFT semiactive controller for base isolated buildings with variable stiffness isolation systems  

Microsoft Academic Search

A new short time Fourier transformation (STFT) control algorithm is developed for reducing the response of base isolated buildings with variable stiffness isolation systems in near fault earthquakes. The central idea of STFT is to break up the signal into small time segments and Fourier analyze each time segment to ascertain the frequencies that exist in it. For each different

Sriram Narasimhan; Satish Nagarajaiah

2005-01-01

436

Feed-forward control of active variable stiffness systems for mitigating seismic hazard in structures  

Microsoft Academic Search

In this paper we discuss a practical two-stage approach (design and operation) to the seismic control of structures equipped with active variable stiffness (AVS) systems, as a means to mitigate or eliminate resonance or near-resonance phenomena in structures due to seismic ground motion. During the design stage, past seismic events are processed to extract the characteristic frequency content against which

Nikos G. Pnevmatikos; Loukas F. Kallivokas; Charis J. Gantes

2004-01-01

437

Human Resource Flexibility as a Mediating Variable Between High Performance Work Systems and Performance  

Microsoft Academic Search

Much of the human resource management literature has demonstrated the impact of high performance work systems (HPWS) on organizational performance. A new generation of studies is emerging in this literature that recommends the inclusion of mediating variables between HPWS and organizational performance. The increasing rate of dynamism in competitive environments suggests that measures of employee adaptability should be included as

Inmaculada Beltrán-Martín; Vicente Roca-Puig; Ana Escrig-Tena; Juan Carlos Bou-Llusar

2008-01-01

438

Extending the Four-Variable Model for Cyber-Physical Systems  

Microsoft Academic Search

As Cyber-physical System (CPS) is gaining more and more concerns recently, the requirements modeling becomes a critical issue in CPS. In this paper we propose a requirements model for CPS by extending the Four-Variable Model. Through extension, the requirements model deals with complex network environment that CPS are facing, and views timing and position requirements as functional requirements. Besides the

Xiaohong Chen; Mingsong Chen

2012-01-01