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1

Dynamics of Variable Mass Systems  

NASA Technical Reports Server (NTRS)

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

Eke, Fidelis O.

1998-01-01

2

Mass-variable TLD systems and their seismic performance  

NASA Astrophysics Data System (ADS)

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

Xin, Yuxiang; Chen, Genda

2007-04-01

3

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

4

Deconstructed Transverse Mass Variables  

E-print Network

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

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

2014-09-09

5

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

6

Earth? Mass Variability  

E-print Network

The perturbation of the Earth caused by variability of mass of Earth as additional reason with gravity of celestial bodies and shape of the Earth. The Earth eating and collecting matters from space and loss or eject matters to space through its flying in the space around the Sun. The source of the rising in the global sea level is not closed in global warming and icebergs, but the outer space is the additional important source for this rising. The Earth eats waters from space in unknown mechanism. The mass of the Earth become greater in November i.e. before transit apoapsis two months, and become latter in February i.e. after transit apoapsis to two months.

Ramy Mawad

2014-02-12

7

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

8

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

NASA Astrophysics Data System (ADS)

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

Lopez Velazquez, Gustavo; Juarez, Esmeralda

2013-04-01

9

Simultaneous isotopic analysis of uranium and plutonium by thermal ionisation mass spectrometry coupled to a variable multicollection detection system  

NASA Astrophysics Data System (ADS)

Simultaneous isotopic analysis of uranium and plutonium employing a thermal ionisation mass spectrometer coupled to a variable multicollection Faraday cup detector system is reported. Factors such as the U/Pu ratio in the sample, filament currents during sample de-gassing and data acquisition have been investigated to arrive at optimum conditions for analysis. A simple correction to the observed 235/238 peak ratio is necessary to account for the 238Pu isotope's contribution to 238U. The precision and accuracy achievable in the measurement of isotopic ratios is better than 0.2%. An attempt was also made to show that uranium and plutonium vaporise predominantly through their oxides and not through direct metal evaporation when the samples are loaded from dilute nitric acid medium. This might explain the earlier appearance of U+ ions in preference to Pu+ ions in the mass spectra of all the U/Pu mixtures investigated.

Ramakumar, K. L.; Rao, R. M.; Gnanayyan, L.; Jain, H. C.

1994-06-01

10

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

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

11

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

SciTech Connect

New multi-color photometry for the eclipsing binary DZ Psc was performed in 2011 and 2012 using the 85 cm telescope at the Xinglong Station of the National Astronomical Observatories of China. Using the updated Wilson-Devinney (W-D) code, we deduced two sets of photometric solutions. The overcontact degree is f = 89.7({+-} 1.0)%, identifying DZ Psc as a deep, low mass ratio overcontact binary. The asymmetric light curves (i.e., LC{sub 2} in 2012) were modeled by a hot spot on the primary star. Based on all of the available light minimum times, we discovered that the orbital period of DZ Psc may be undergoing a secular period increase with a cyclic variation. The modulated period and semi-amplitude of this oscillation are P{sub mod} = 11.89({+-} 0.19) yr and A = 0.0064({+-} 0.0006) days, which may be possibly attributed to either cyclic magnetic activity or light-time effect due to the third body. The long-term period increases at a rate of dP/dt=+7.43({+-}0.17) Multiplication-Sign 10{sup -7} days yr{sup -1}, which may be interpreted as conserved mass transfer from the less massive component to the more massive one. With mass transferring, DZ Psc will finally merge into a rapid-rotation single star when J{sub spin}/J{sub orb} > 1/3.

Yang, Y.-G.; Dai, H.-F. [School of Physics and Electronic Information, Huaibei Normal University, 235000 Huaibei, Anhui Province (China); Qian, S.-B. [National Astronomical Observatories/Yunnan Observatory, Chinese Academy of Sciences, 650011 Kunming (China); Zhang, L.-Y. [Department of Physics, College of Science, Guizhou University, 550025 Guiyang (China); Soonthornthum, B., E-mail: yygcn@163.com, E-mail: qsb@ynao.ac.cn [National Astronomical Research Institute of Thailand/Ministry of Science and Technology, Bangkok (Thailand)

2013-08-01

12

Mass transfer cycles in cataclysmic variables  

NASA Technical Reports Server (NTRS)

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

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

1995-01-01

13

Black hole mass and variability in quasars  

E-print Network

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

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

2008-07-24

14

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

PubMed

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

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

2013-10-01

15

Mass Storage Systems.  

ERIC Educational Resources Information Center

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

Ranade, Sanjay; Schraeder, Jeff

1991-01-01

16

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

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

17

Variable camshaft timing system  

SciTech Connect

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

Sapienza, S.J.

1988-05-17

18

Ultra High Mass Range Mass Spectrometer System  

DOEpatents

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

Reilly, Peter T. A. [Knoxville, TN

2005-12-06

19

Variability in properties of Salado Mass Concrete  

SciTech Connect

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

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

1995-08-01

20

Modelling Variability for System Families  

Microsoft Academic Search

In this paper, an approach to facilitate the treatment with variabilities in system families is presented by explicitly modelling variants. The proposed method of managing variability consists of a variant part, which models variants and a decision table to depict the customisation decision regarding each variant. We have found that it is easy to implement and has advantage over other

Shamim Hasnat Ripon; Kamrul Hasan Talukder; Khademul Islam Molla

2010-01-01

21

Modelling Variability for System Families  

E-print Network

In this paper, an approach to facilitate the treatment with variabilities in system families is presented by explicitly modelling variants. The proposed method of managing variability consists of a variant part, which models variants and a decision table to depict the customisation decision regarding each variant. We have found that it is easy to implement and has advantage over other methods. We present this model as an integral part of modelling system families.

Ripon, Shamim H

2010-01-01

22

Variable buoyancy system metric  

E-print Network

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

Jensen, Harold Franklin

2009-01-01

23

Characterization and modeling of a novel electro-hydraulic variable two-terminal mass device  

NASA Astrophysics Data System (ADS)

Much effort has been devoted to developing variable stiffness and variable damping devices for semi-active structural vibration control. However, little research has been done for variable inertial mass mainly caused by the mechanical terminal limit of the mass component. Based on the two-terminal mass scheme, we propose an electro-hydraulic approach to realizing a novel device with variable two-terminal mass. In this study, the flywheel that is traditionally handled by one physical terminal is manipulated by two terminals of a hydraulic cylinder-control-motor system. The transmission ratio of the system is adjusted using an electro-hydraulic proportional valve. Through modeling the ideal dynamic behavior, it is confirmed that the equivalent inertial mass between two terminals of the component can be made variable. To further understand its mechanical characteristics, a prototype device is developed and tested on a test rig. Triangular and sinusoidal excitation signals are employed respectively to identify the model parameters. The results show that the proposed model can describe the dynamic characteristics of the variable two-terminal mass device well. The proposed design and modeling schemes pave the way towards the semi-active variable inertial mass control of vibration systems.

Li, C.; Liang, M.

2012-02-01

24

The Ages, Masses, Evolution and Kinematics of Mira variable  

E-print Network

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

Michael Feast

2008-12-01

25

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

26

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

27

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

NASA Technical Reports Server (NTRS)

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

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

2008-01-01

28

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

NASA Technical Reports Server (NTRS)

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

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

1975-01-01

29

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

NASA Astrophysics Data System (ADS)

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

Starinova, Olga L.; Salmin, Vadim V.

2014-12-01

30

Quasar Variability and Black Hole Mass with the NFO Webscope  

NASA Astrophysics Data System (ADS)

To help corroborate the findings of correlations between quasar variability and black hole mass, we investigated the structures and upper limits to the emitting regions of a small sample of quasars using the remotely operated 24 inch NFO Webscope near Silver City, NM. By studying the variability of the quasar magnitudes in optical wavebands, we were able to make estimates as to the radius of the central emitting region. The quasars were chosen at a range of redshifts, and observed during the summers of 2005 and 2006. The data from 2005 has been analyzed and variations in magnitude of 0.0237, -0.0385, and 0.5602 were observed in three different quasars over a period of days (Fleming & Kennefick 2005 BAAS 20714101). We have analyzed the 2006 data set of the same quasars to compare the variations with those obtained in the 2005 data, which allowed us to study variations on timescales of both days and months. Spectra of the quasars were obtained from the published literature which allowed us to derive estimates of the black hole mass using standard techniques. We additionally discuss whether the results are supportive of a variability-black hole mass relationship. Although our quasar sample is small, it is hoped our research will aid in enhancing the understanding of inter-relationships among intrinsic quasar parameters. This work was funded by an NSF REU Supplement and an Arkansas CSAPS Research Grant.

Walton, Josiah; Fleming, B.; Thomas, T.; Kennefick, J.

2007-05-01

31

Unsteady mass transfer around axisymmetric drops of revolution in variable diffusion coefficient liquids  

Microsoft Academic Search

Unsteady mass transfer in the continuous phase around axisymmetric drops of revolution at high Peclet numbers has been theoretically studied. The liquid is a binary system, having a variable diffusion coefficient, which depends on the solute concentration. The solution to the problem was obtained by extending the theory of Favelukis and Mudunuri, developed for a constant diffusion coefficient liquid. The

Moshe Favelukis

2008-01-01

32

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

NASA Technical Reports Server (NTRS)

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

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

1983-01-01

33

A new absolute magnitude calibration with 2MASS for cataclysmic variables  

NASA Astrophysics Data System (ADS)

Using reliable trigonometric measurements, we find that the absolute magnitude of cataclysmic variables depends on the orbital period and de-reddened ( J - H) 0 and ( H - Ks) 0 colours of 2MASS (Two Micron All Sky Survey) photometric system. The calibration equation covers the ranges 0.032 d < Porb ? 0.454 d, -0.08 < ( J - H) 0 ? 1.54, -0.03 < ( H - Ks) 0 ? 0.56 and 2.0 < MJ < 11.7; It is based on trigonometric parallaxes with relative errors of ( ??/ ?) ? 0.4. By using the period-luminosity-colours (PLCs) relation, we estimated the distances of cataclysmic variables with orbital periods and 2MASS observations and compared them with distances found from other methods. We suggest that the PLCs relation can be a useful statistical tool to estimate the distances of cataclysmic variables.

Ak, T.; Bilir, S.; Ak, S.; Retter, A.

2007-08-01

34

Binary system parameters and the hibernation model of cataclysmic variables  

SciTech Connect

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

Livio, M.; Shara, M.M.

1987-08-01

35

On exchangeable continuous variable systems  

NASA Astrophysics Data System (ADS)

We investigate permutation-invariant continuous variable quantum states and their covariance matrices. We provide a complete characterization of the latter with respect to permutation invariance and exchangeability and representing convex combinations of tensor power states. On the level of the respective density operators this leads to necessary criteria for all these properties which become necessary and sufficient for Gaussian states. For these we use the derived results to provide de Finetti-type theorems for various distance measures.

König, Robert; Wolf, Michael M.

2009-01-01

36

Belt type continuously variable transmission system  

SciTech Connect

This patent describes a belt type continuously variable transmission system comprising: a belt type continuously variable transmission device wherein a transmission belt is racked across an input pulley and an output pulley and rotation is continuously variably transmitted from the input pulley to the output pulley; and an auxiliary transmission device disposed on the output side of the belt type continuously variable transmission device and having at least a forward-reverse shift mechanism, wherein the belt type continuously variable transmission device and the auxiliary transmission device are respectively housed in a belt type continuously variable transmission device housing and an auxiliary transmission device housing, both of which are formed by case members and separated by a radial partition member of the case members into independent sealed housings, respectively, and wherein the auxiliary transmission device is detacheble from the continuously variable transmission device housing as an independent unit.

Okada, M.; Morisawa, K.; Kakamu, M.; Kato, N.

1988-11-15

37

Separation of Variables for the Ruijsenaars System  

NASA Astrophysics Data System (ADS)

We construct a separation of variables for the classical n-particle Ruijsenaars system (the relativistic analog of the elliptic Calogero-Moser system). The separated coordinates appear as the poles of the properly normalised eigenvector (Baker-Akhiezer function) of the corresponding Lax matrix. Two different normalisations of the BA functions are analysed. The canonicity of the separated variables is verified with the use of the r-matrix technique. The explicit expressions for the generating function of the separating canonical transform are given in the simplest cases n=2 and n=3. Taking the nonrelativistic limit we also construct a separation of variables for the elliptic Calogero-Moser system.

Kuznetsov, V. B.; Nijhoff, F. W.; Sklyanin, E. K.

38

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

NASA Technical Reports Server (NTRS)

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

Bowen, G. H.

1989-01-01

39

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

40

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

PubMed

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

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

2014-06-01

41

Quantifying decoherence in continuous variable systems  

Microsoft Academic Search

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

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

2005-01-01

42

Aggregation of Variables and System Decomposition: Applications  

E-print Network

that the aggregate variable descriptions of mutation-selection systems offer a potential formal definition of units decomposi- tion operators. It is also shown that equitable partitions have a natural application to the description of mutation-selection matrices (fitness landscapes) when their fitness functions have certain

Stadler, Peter F.

43

System for variable spectra solar light source  

Microsoft Academic Search

We present a variable spectral and angular light source generator. The design and presented results are focused on solar radiation simulation, reproducing the spectral and angular distribution observed from the sun. This system is particularly interesting in the area of solar concentration. It permits to measure and test multi-junction photovoltaic cells alone or together with concentrating optics. We present some

Juan C. M. Antón; José A. Gómez-Pedrero; Daniel Vázquez; Eusebio Bernabeu

2009-01-01

44

Ratio control system for continuously variable transmission  

SciTech Connect

This patent describes a ratio control system for a continuously variable transmission which performs a feedback control wherein an integral control gain and a proportional control gain are varied depending upon the level of a line pressure that is used to actuate a pulley unit during shifting operation.

Oshiage, K.

1987-10-27

45

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

46

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

47

Temporal variability of mass transport across Canary Islands Channels  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

48

Dynamically variable spot size laser system  

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

49

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

50

Long-term variability of high-mass X-ray binaries. I. Photometry  

NASA Astrophysics Data System (ADS)

We present photometric observations of the field around the optical counterparts of high-mass X-ray binaries. Our aim is to study the long-term photometric variability in correlation with their X-ray activity and derive a set of secondary standard stars that can be used for time series analysis. We find that the donors in Be/X-ray binaries exhibit larger amplitude changes in the magnitudes and colours than those hosting a supergiant companion. The amplitude of variability increases with wavelength in Be/X-ray binaries and remains fairly constant in supergiant systems. When time scales of years are considered, a good correlation between the X-ray and optical variability is observed. The X-rays cease when optical brightness decreases. These results reflect the fact that the circumstellar disk in Be/X-ray binaries is the main source of both optical and X-ray variability. We also derive the colour excess, E(B - V), selecting data at times when the contribution of the circumstellar disk was supposed to be at minimum, and we revisit the distance estimates. Finding charts with the identification of the secondary standard stars are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/574/A33

Reig, P.; Fabregat, J.

2015-02-01

51

Imaging findings of variable axillary mass and axillary lymphadenopathy.  

PubMed

The axilla is a triangular space that contains mesenchymal tissues such as fat, vessels, nerves and lymph nodes, from which various diseases can develop. This article describes axillary masses and axillary lymphadenopathies using imaging findings from techniques such as ultrasonography, mammography, computed tomography and magnetic resonance imaging. Awareness of the characteristic imaging findings of disease entities that cause axillary masses and various axillary lymphadenopathies will help in the accurate diagnosis of axillary lesions. PMID:24948395

Park, Sung Hee; Jeong, Yu Mi; Cho, So Hyun; Jung, Hyun Kyung; Kim, Soo Jin; Ryu, Han Suk

2014-09-01

52

Variable/Multispeed Rotorcraft Drive System Concepts  

NASA Technical Reports Server (NTRS)

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

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

2009-01-01

53

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

54

THE ENIGMATIC YOUNG, LOW-MASS VARIABLE TWA 30  

E-print Network

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

Looper, Dagny L.

55

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

56

Aperiodic variability of low-mass X-ray binaries at very low frequencies  

E-print Network

We have obtained discrete Fourier power spectra of a sample of persistent low-mass neutron-star X-ray binaries using long-term light curves from the All Sky Monitor on board the Rossi X-ray Timing Explorer. Our aim is to investigate their aperiodic variability at frequencies in the range 1 x 10^{-7}-5 x 10^{-6} Hz and compare their properties with those of the black-hole source Cyg X-1. We find that the classification scheme that divides LMXBs into Z and atoll sources blurs at very low frequencies. Based on the long-term (~ years) pattern of variability and the results of power-law fits (P ~ v^{-a}) to the 1 x 10^{-7}-5 x 10^{-6} Hz power density spectra, low-mass neutron-star binaries fall into three categories. Type I includes all Z sources, except Cyg X-2, and the atoll sources GX9+1 and GX13+1. They show relatively flat power spectra (a 30%) and exhibit the steepest power spectra (a > 1.2). The sources 4U 1705-44, GX354-0 and 4U 1820-30 belong to this group. GX9+9 and Cyg X-2 appear as intermediate systems in between Type I and II and Type II and III sources, respectively. We speculate that the differences in these systems may be caused by the presence of different types of mass-donor companions. Other factors, like the size of the accretion disc and/or the presence of weak magnetic fields, are also expected to affect their low-frequency X-ray aperiodic varibility.

P. Reig; I. Papadakis; N. D. Kylafis

2002-11-20

57

NEREUS Nemertes : embedded mass spectrometer control system  

E-print Network

In this thesis, I present Nemertes System, a software suite to control an embedded autonomous mass spectrometer. I first evaluate previous control systems for the hard- ware and evaluate a set of software design goals. The ...

Champy, Adam Samuel

2005-01-01

58

Variable temperature seat climate control system  

DOEpatents

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

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

1997-05-06

59

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

Microsoft Academic Search

In this poster we present a preliminary model of cataclysmic variables, close binary systems consisting of a white dwarf primary and a lower mass main-sequence secondary star. Mass transfer from the secondary results in the formation of an accretion disk surrounding the primary. We modeled the accretion disk with the method of smoothed particle hydrodynamics (SPH), as implemented in the

Laura Kreidberg; M. Wood; M. Wetzstein

2010-01-01

60

Control system for an infinitely variable transmission  

SciTech Connect

A system for controlling an infinitely variable transmission is described for transmitting the power of an internal combustion engine having a throttle. A clutch operatively connects the engine to the transmission. The transmission comprises a drive pulley having a hydraulically shiftable first disc and a first hydraulic cylinder for shifting the first disc. A driven pulley has a hydraulically shiftable second disc and a second hydraulic cylinder for operating the second disc, and a belt engaged with both pulleys. The system comprises a pressure oil circuit having a pump for supplying oil for the cylinders, a line pressure control valve having a first spool for controlling line pressure of pressurized oil from the pump, and a transmission ratio control valve having a second spool for controlling the pressurized oil to move the first disc of the drive pulley. This changes the transmission ratio of the transmission.

Morimoto, Y.

1987-06-16

61

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

E-print Network

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

Sheridan, Scott

62

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

NASA Astrophysics Data System (ADS)

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

May, Jody C.; Russell, David H.

2011-07-01

63

Gas sampling system for a mass spectrometer  

DOEpatents

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

2003-12-30

64

Quantifying decoherence in continuous variable systems  

E-print Network

We present a detailed report on the decoherence of quantum states of continuous variable systems under the action of a quantum optical master equation resulting from the interaction with general Gaussian uncorrelated environments. The rate of decoherence is quantified by relating it to the decay rates of various, complementary measures of the quantum nature of a state, such as the purity, some nonclassicality indicators in phase space and, for two-mode states, entanglement measures and total correlations between the modes. Different sets of physically relevant initial configurations are considered, including one- and two-mode Gaussian states, number states, and coherent superpositions. Our analysis shows that, generally, the use of initially squeezed configurations does not help to preserve the coherence of Gaussian states, whereas it can be effective in protecting coherent superpositions of both number states and Gaussian wave packets.

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

2005-02-25

65

Control system for a infinitely variable transmission  

SciTech Connect

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

Morimoto, Y.

1988-11-15

66

Control system for an infinitely variable transmission  

SciTech Connect

A system is described for controlling an infinitely variable transmission for transmitting the power of an internal combustion engine through a clutch for driving a motor vehicle. The transmission comprises a drive pulley having a hydraulically shiftable disc and a hydraulic cylinder for shifting the disc, a driven pulley having a hydraulically shiftable disc and a hydraulic cylinder for operating the disc of the driven pulley, and a belt engaged with both pulleys. The system includes a pressure oil circuit having a pump for supplying pressurized oil, and a transmission ratio control valve having a spool for controlling the pressurized oil so as to move the disc of the drive pulley to change the actual transmission ratio of the transmission. The improvement in the system comprises: first means for moving the spool of the transmission ratio control valve; second means responsive to disengagement of the clutch, when speed of the vehicle is below a predetermined speed, for producing a coasting signal; third means responsive to the coasting signal for producing a drive pulley speed set signal; fourth means responsive to the drive pulley speed set signal for producing a shifting signal representing a quantity of shifting the spool of the transmission ratio control valve in upshifting direction, and fifth means responsive to the shifting signal for shifting the spool of the transmission ratio control valve in the upshifting direction via the first means thereby decreasing the drive pulley speed.

Morimoto, Y.

1987-07-21

67

Control system for a continuously variable transmission  

SciTech Connect

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

Tanaka, H.; Morimoto, Y.

1989-01-03

68

INFRARED VARIABILITY OF THE GLIESE 569B SYSTEM  

SciTech Connect

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

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

2012-06-20

69

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

SciTech Connect

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

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

2011-04-10

70

Mass Storage Performance Information System  

NASA Technical Reports Server (NTRS)

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

Scheuermann, Peter

2000-01-01

71

Seasonal and inter-annual mass variability in Antarctica from GRACE  

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

72

Water mass variability in the western North Pacific detected in a 15-year eddy resolving ocean reanalysis  

Microsoft Academic Search

This paper describes a reanalysis of the variability of water mass properties and currents in the western North Pacific using\\u000a an ocean forecast system, Japan Coastal Ocean Predictability Experiment 2 (JCOPE2), to provide the basic description and information\\u000a about the quality for data users. We have created the reanalysis data with high horizontal resolution of 1\\/12° to describe\\u000a the oceanic

Yasumasa Miyazawa; Ruochao Zhang; Xinyu Guo; Hitoshi Tamura; Daisuke Ambe; Joon-Soo Lee; Akira Okuno; Hiroshi Yoshinari; Takashi Setou; Kosei Komatsu

2009-01-01

73

Asymmetric EPR entanglement in continuous variable systems  

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

74

Kickdown system for an infinitely variable transmission  

SciTech Connect

This patent describes a control system for an infinitely variable transmission for transmitting the power of an internal combustion engine of a vehicle having an accelerator pedal for operating the engine. The transmission comprises a primary pulley having a first hydraulically shiftable disc and a first hydraulic cylinder for shifting the disc, a secondary pulley having a second hydraulically shiftable disc and a second hydraulic cylinder for operating the second disc, and a belt engaged with both pulleys. The system includes a hydraulic circuit having a pump for supplying oil, a transmission ratio control valve provided in the hydraulic circuit and having a spool shiftable in accordance with the speed of the engine for controlling the oil supplied to the cylinder for shifting the first disc of the primary pulley to change the transmission ratio of the transmission, and a pressure regulator valve provided in the circuit and having a spool shiftable in accordance with the transmission ratio for increasing the pressure of the oil applied to the cylinders with an increase of the transmission ratio. The improvement described here comprises: a kickdown switch means operative to produce a kickdown signal upon full depression of the accelerator pedal of the vehicle; and electronic circuit means responsive to the kickdown signal for producing a downshift signal for a period of duration.

Miyawaki, M.

1987-03-24

75

Control system for an infinitely variable transmission  

SciTech Connect

This patent describes a system for controlling the transmission ratio of an infinitely variable transmission for transmitting power of an internal combustion engine. The transmission comprises a primary pulley having a hydraulically shiftable disc and a hydraulic cylinder for shifting the disc, a secondary pulley having a hydraulically shiftable disc and a hydraulic cylinder for operating the disc, and a belt engaged with both of the pulleys. The system comprises a first hydraulic circuit means having a pump for supplying pressurized oil, and a transmission ratio control valve having a spool responsive to speed of the engine for controlling the pressurized oil so as to move the disc of the primary pulley to change the transmission ratio. The improvement described here comprises: a second hydraulic circuit means for applying control oil to one end of the spool of the transmission ratio control valve so as to axially move the spool; an electronic control circuit means responsive to first pulses proportional to the speed of the engine for producing a first output signal dependent on the engine speed; and the electronic control circuit means including range change means, the latter for causing the electronic control circuit means to produce a second output signal dependent on the engine speed.

Miyawaki, M.

1987-04-14

76

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

77

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

NASA Astrophysics Data System (ADS)

Glacio-climatological studies recognise glacier mass balance changes as high-confident climate indicators. The climatic sensitivity of a glacier does not simply depend on regional climate variability but also influenced via large- and mesoscale atmospheric circulation patterns. This study focuses on recent changes in the mass balance using records from three border regions of Europe, and investigates the relationships between the seasonal mass balance components, regional climatic conditions, and distant atmospheric forcing. Since glaciers in different macro-climatological conditions (i.e., mid-latitudes or high-latitudes, dry-continental or maritime regions) may present strongly diverse mass balance characteristics, the three analysed regions were selected from different glacierised macroregions (using the database of the World Glacier Monitoring Service). These regions belong to the Caucasus Mountains (Central Europe macroregion), the Polar Ural (Northern Asia macroregion), and Svalbard (Arctic Islands macroregion). The analysis focuses on winter, summer, and annual mass balance series of eight glaciers. The climatic variables (atmospheric pressure, air temperature, precipitation) and indices of teleconnection patterns (e.g., North Atlantic Oscillation, Pacific Decadal Oscillation) are used from the gridded databases of the University of East Anglia, Climatic Research Unit and the National Oceanic and Atmospheric Administration, National Center for Environmental Prediction. However, the period and length of available mass balance data in the selected regions vary greatly (the first full record is in 1958, Polar Ural; the last is in 2010, Caucasus Mountains), a comparative analysis can be carried out for the period of 1968-1981. Since glaciers from different regions respond to large- and mesoscale climatic forcings differently, and because the mass balance of glaciers within a region often co-vary, our specific objectives are (i) to examine the variability and the integrative climatic signal in the averaged mass balance records of the selected regions; (ii) to analyse the possible coupling between the mass balance and climatic variables, including the dominant patterns of Northern Hemisphere climate variability; and (iii) to compare the main characteristics of the three regions. Furthermore, (iv) a short discussion is given considering the significant decreasing trend of the cumulative annual mass balances in every region under the detected climatic changes in the second half of the 20th century. Preliminary results suggest that the strongest teleconnection links could be between winter mass balance and winter NAO for the Polar Ural (r=0.46, p<0.05), and between annual mass balance and PDO for Svalbard (r=-0.43, p<0.05). Neither seasonal, nor annual mass balance records showed significant correlation with any of the examined circulation indices for the Caucasus.

Lehoczky, Annamária; Kern, Zoltán; Pongrácz, Rita

2014-05-01

78

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

79

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

80

An analysis of space power system masses  

NASA Technical Reports Server (NTRS)

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

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

1990-01-01

81

Control system for a continuously variable transmission  

SciTech Connect

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

Sakai, Y.

1987-11-03

82

Control system for an infinitely variable transmission  

SciTech Connect

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

Sakai, Y.

1986-12-09

83

Control system for an infinitely variable transmission  

SciTech Connect

This patent describes a control system for an infinitely variable transmission for transmitting the power of an internal combustion engine mounted on a vehicle. The transmission comprises: a primary pulley operatively connected to a crankshaft of the engine having a hydraulically shiftable disc and a first hydraulic cylinder for shifting the disc; a secondary pulley operatively connected to an output shaft and having a hydraulically shiftable disc and a second hydraulic cylinder for operating the disc of the secondary pulley; a belt engaged with both pulleys; a first hydraulic circuit having a pump for supplying oil; a transmission ratio control valve responsive to engine speed for controlling the oil so as to shift the disc of the primary pulley to change the transmission ratio; and a pressure regulator valve responsive to the transmission ratio for increasing line pressure of the hydraulic circuit with an increase of the transmission ratio. The improvement is described comprising: means comprising a piston axially slidably mounted in the first hydraulic cylinder of the primary pulley defining a piston chamber in the first hydraulic cylinder. The means is included for restricting shifting of the disc of the primary pulley to a maximum transmission ratio of the transmission so as to limit movement of the disc of the primary pulley at a restricted position where the transmission ratio is lower than the maximum transmission ratio of the transmission; and a second hydraulic circuit provided between the pump and the piston chamber.

Miyawaki, M.

1987-04-14

84

Solar Forecasting System and Irradiance Variability Characterization  

E-print Network

variability. The report was submitted by HNEI to the U.S. Department of Energy Office of Electricity Delivery Variability in Hawai`i Prepared for the U.S. Department of Energy Office of Electricity Delivery and Energy of the Hawaiian Islands, with locations of the data sets used in the analysis 2 2. Statistics from irradiance

85

System-Level Integration of Mass Memory  

NASA Technical Reports Server (NTRS)

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

Cox, Brian; Mellstrom, Jeffrey; Wysocky, Terry

2008-01-01

86

Tropical Pacific Variability in the NCAR Climate System Model  

Microsoft Academic Search

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

Bette L. Otto-Bliesner; Esther C. Brady

2001-01-01

87

Variability of mass changes at basin scale for Greenland and Antarctica  

NASA Astrophysics Data System (ADS)

During the last decade, the GRACE mission has provided valuable data for determining the mass changes of the Greenland and Antarctic ice sheets. Yet, discrepancies still exist in the published mass balance results, and analyses on the sources of errors and discrepancies are lacking. Here, we present monthly mass changes together with trends derived from GRACE data at basin scale for both the Greenland and Antarctica ice sheets and we assess, for the first time systematically, the variability and errors for each of the possible sources of discrepancies: mass inference methods, data sets and background models. We find a very good agreement between the monthly mass change results derived from two independent methods, which represents a cross validation. For the monthly solutions, we find that most of the variability is caused by the use of different data sets rather than different methods. Besides the well-known GIA trend uncertainty, we find that the degree-1 variability and the recent de-aliasing corrections have significant impact on monthly time series and trends respectively. We also show the remarkable differences between the use of release RL04 and the new RL05, and how the latter results in smaller mass trends for the majority of the basins. The overall variability of the solutions well exceeds the uncertainties propagated from the data errors and the leakage (as done in the past), hence we calculate new sound total errors for the monthly solutions and the trends. For the whole GRACE period our trend estimate for Greenland is -234 ± 20 Gt yr-1 and -83 ± 36 Gt yr-1 for Antarctica (-111 ± 15 Gt yr-1 in the western part). These trends show a clear (with respect to our errors) increase of mass loss in the last four years.

Barletta, V. R.; Sørensen, L. S.; Forsberg, R.

2012-08-01

88

The relation between the relativistic 5D Wesson theory and the Newtonian variable mass theory  

NASA Astrophysics Data System (ADS)

The existence of Newtonian analogs to spatially homogeneous and isotropic cosmological models of the relativistic 5D Wesson variable mass theory is investigated. By treating the continuous universe “matter creation process” by the methods of standard hydrodynamics, it is shown that classical analogs are obtained only if the cosmological constant is null and the spatial curvature is positive.

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

1992-02-01

89

Long period variables in 47 Tuc: direct evidence for lost mass  

E-print Network

We have identified 22 new variable red giants in 47 Tuc and determined periods for another 8 previously known variables. All red giants redder than V-I_c=1.8 are variable at the limits of our detection threshold, which corresponds to delta V ~ 0.1 mag. This colour limit corresponds to a luminosity log L/L_sun=3.15 and it is considerably below the tip of the RGB at log L/L_sun=3.35. Linear non-adiabatic models without mass loss on the giant branch can not reproduce the observed PL laws for the low amplitude pulsators. Models that have undergone mass loss do reproduce the observed PL relations and they show that mass loss of the order of 0.3 M_sun occurs along the RGB and AGB. The linear pulsation periods do not agree well with the observed periods of the large amplitude Mira variables, which pulsate in the fundamental mode. The solution to this problem appears to be that the nonlinear pulsation periods in these low mass stars are considerably shorter than the linear pulsation periods due to a rearrangement of stellar structure caused by the pulsation. Both observations and theory show that stars evolve up the RGB and first part of the AGB pulsating in low order overtone modes, then switch to fundamental mode at high luminosities.

T. Lebzelter; P. R. Wood

2005-07-21

90

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

91

Fan energy use in variable air volume systems  

Microsoft Academic Search

Fan energy consumption in variable air volume (VAV) systems is affected by both the technique used to control the flow rate and the control algorithm used. In this paper a simulation study is made of a ''standard'' 10,000 square foot building. Three flow-control techniques- system dampers, inlet vane control, and variable speed control- are considered along with two types of

P. W. Brothers; M. L. Warren

1986-01-01

92

Mass Transit Living Lab: Improve the System  

NSDL National Science Digital Library

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

Civil And Environmental Engineering Department

93

Climate variability and deep water mass characteristics in the Aegean Sea  

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

94

VizieR Online Data Catalog: 2MASS photometry of cataclysmic variables (Ak+, 2008)  

NASA Astrophysics Data System (ADS)

Spatial distribution, galactic model parameters and luminosity function of cataclysmic variables (CVs) in the solar neighbourhood have been found using distances estimated from the period-luminosity-colours (PLCs) relation of CVs. It can be concluded that exponential function fits better to the observational z-distributions of the whole CVs in the sample, non-magnetic CVs and dwarf novae, while the sech2 function is more appropriate for nova-like stars and polars. The vertical scaleheight of CVs is 158+/-14pc for the 2MASS J band limiting apparent magnitude of 15.8. The discrepancies between the theoretical and observational population studies of CVs can be at least partly removed if the sech2 density function is used in deriving the galactic model parameters. We estimated the vertical scaleheights of 128+/-20pc and 160+/-5pc for dwarf novae and nova-like stars, respectively. The local space density of CVs is found ~3x10-5pc-3 which is in agreement with the lower limit of the theoretical predictions. The luminosity function of CVs shows a trend toward higher space density at low luminosity, implying an increase in the number of short-period systems. (1 data file).

Ak, T.; Bilir, S.; Ak, S.; Eker, Z.

2007-08-01

95

Evolution of the orbital-plane orientations in the two-protoplanet three-body problem with variable masses  

NASA Astrophysics Data System (ADS)

The three body problem with variable masses with two of the bodies being protoplanets is analyzed. The protoplanetary masses are assumed to be much less than the protosolar mass: m 1( t) ? m 0( t), m 2( t) ? m 0( t). The variations of the body masses over time are assumed to be known. The masses vary isotropically with different rates: ? 0/ m 0? ? 1/ m 1, ? 0/ m 0? ? 2/ m 2, ? 1/ m 1? ? 2/ m 2. The bodies are treated like material points. The problem is described by analogy to the second system of Poincaré elements, based on the equations of motion in a Jacobian coordinate system. Individual aperiodic motions in a quasi-conical cross section are used as the initial, unperturbed, intermediate motions. The expression for the perturbing function does not include terms proportional to third and higher powers of the small masses m 1 and m 2. A new analytical expression for the perturbing function analogous to the second system of the Poincaré variables is obtained in the formulation considered using a classical scheme. The analogs of the eccentricities e 1 and e 2 and the orbital inclinations i 1 and i 2 are considered to be small. The perturbing function accurate to within terms of second order in the small quantities e 1, e 2, i 1, and i 2 is calculated in a symbolic form using Mathematica package. The equations for the secular perturbations in this protoplanetary three-body problem, with the bodies treated as points with masses varying isotropically with different rates, are obtained. General rigorous analytical solutions to these equations for the secular perturbations describing the evolution of the orbital planes are derived for oblique elements, for arbitrary mass-variation laws. An analog of the Laplace theorem is proved for the orbital inclinations. Analytical formulas are obtained for the temporal variation of the longitudes of the ascending nodes and the inclinations for arbitrary mass variations with different rates. It is shown that the Jacobian node theorem, which is valid in the classical three-body problem with constantmasses, is violated in this problem, unless special initial conditions apply.

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

2014-09-01

96

Toward Scalable Benchmarks for Mass Storage Systems  

NASA Technical Reports Server (NTRS)

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

Miller, Ethan L.

1996-01-01

97

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

NASA Technical Reports Server (NTRS)

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

Jones, Harry

2003-01-01

98

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

99

Error response test system and method using test mask variable  

NASA Technical Reports Server (NTRS)

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

Gender, Thomas K. (Inventor)

2006-01-01

100

Expert overseer for mass spectrometer system  

DOEpatents

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

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

1991-01-01

101

PERFORMANCE OF A VARIABLE RATE CENTER PIVOT SYSTEM  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

102

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

103

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

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

104

Mechanism studies of seasonal variability of dissolved oxygen in Mass Bay: A multi-scale FVCOM/UG-RCA application  

E-print Network

Mechanism studies of seasonal variability of dissolved oxygen in Mass Bay: A multi-scale FVCOM Accepted 7 December 2013 Available online 14 December 2013 Keywords: Coastal Modeling Dissolved oxygen Mass that the dissolved oxygen (DO) concentration in Mass Bay exhibits a well-defined seasonal cycle, highest in March

Chen, Changsheng

105

Mass spectrometer vacuum housing and pumping system  

DOEpatents

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

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

1996-07-23

106

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

107

Development of Variable Camber Continuous Trailing Edge Flap System  

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

108

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.

109

Variable emissivity laser thermal control system  

DOEpatents

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

Milner, Joseph R. (Livermore, CA)

1994-01-01

110

Mass Properties for Space Systems Standards Development  

NASA Technical Reports Server (NTRS)

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

Beech, Geoffrey

2013-01-01

111

Interannual variability of mass transport in the Canary region from LADCP data  

NASA Astrophysics Data System (ADS)

The variability of the Canary Current is a widely studied topic regarding its role as eastern boundary of the North Atlantic Subtropical Gyre. The Canary region provides indeed an interesting study area in terms of estimating variability scales of the Subtropical Gyre as well as the water masses dynamics. RAPROCAN (RAdial PROfunda de CANarias - Canary deep hydrographic section) is a project based on the reaching of these goals through the obtaining of hydrographic measures during cruises taking place approximately along 29°N, to the North of the Canary Archipelago, twice a year since 2006. The full depth sampling carried out allows the study of temperature and salinity distribution and the calculation of mass transports across the section. The transport estimates are compared to those obtained from previous measurements and estimates in the region. Therefore, transports and their variability through the last decade are quantified. The most significant advance made to previous works is the use of LADCP (Lowered Acoustic Doppler Current Profiler) data informing the initial geostrophic calculations. Thus, corrections are applied to each geostrophic profile considering the reference velocity obtained from LADCP data. ADCP-referenced transport estimates are obtained, providing a successful comparison between the velocity fields obtained from the hydrographic measures. While this work shows the interannual variability observed in winter since 1997, preliminary results confirm previous hypotheses about the magnitude of the Canary Current. Those results including LADCP data also provide new aspects in the circulation distribution across the Canary Archipelago. Also moored current meter data were taken into account in the up close study of the Current through the Lanzarote Passage. Interesting conclusions were drawn that certify the usefulness of LADCP data in referencing geostrophic calculations, while corroborating the results obtained through this methodology. Hence, this work permits the quantification of mass fluxes across the section as well as the study of the water masses located in the Canary Basin and the further analysis of the Subtropical Gyre variability with regards to its significance in the circulation and dynamics concerning the North Atlantic Ocean.

Comas-Rodríguez, Isis; Hernández-Guerra, Alonso; Vélez-Belchí, Pedro; Fraile-Nuez, Eugenio

2010-05-01

112

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

2012-05-15

113

Control system for a continuously variable transmission  

SciTech Connect

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

Vahabzadeh, H.

1986-08-26

114

Variable-Speed Wind System Design : Final Report.  

SciTech Connect

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

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

1993-10-01

115

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

116

On-shell constrained $M_2$ variables with applications to mass measurements and topology disambiguation  

E-print Network

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

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

2014-01-07

117

Dynamic simulation of variable capacity refrigeration systems under abnormal conditions  

Microsoft Academic Search

There are often abnormal working conditions at evaporator outlet of a refrigeration system, such as two-phase state in transient process, and it is essential to investigate such transient behaviours for system design and control strategy. In this paper, a dynamic lumped parameter model is developed to simulate the transient behaviours of refrigeration system with variable capacity in both normal and

Nan Liang; Shuangquan Shao; Changqing Tian; Yuying Yan

2010-01-01

118

Long period variables and mass loss in the globular clusters NGC 362 and NGC 2808  

NASA Astrophysics Data System (ADS)

Context. The pulsation periods of long period variables (LPVs) depend on their mass and helium abundance as well as on their luminosity and metal abundance. Comparison of the observed periods of LPVs in globular clusters with models is capable of revealing the amount of mass lost on the giant branch and the helium abundance. Aims: We aim to determine the amount of mass loss that has occurred on the giant branches of the low metallicity globular clusters NGC 362 and NGC 2808. We also aim to see if the LPVs in NGC 2808 can tell us about helium abundance variations in this cluster. Methods: We have used optical monitoring of NGC 362 and NGC 2808 to determine periods for the LPVs in these clusters. We have made linear pulsation models for the pulsating stars in these clusters taking into account variations in mass and helium abundance. Results: Reliable periods have been determined for 11 LPVs in NGC 362 and 15 LPVs in NGC 2808. Comparison of the observed variables with models in the log P-K diagram shows that mass loss of ~0.15-0.2 M? is required on the first giant branch in these clusters, in agreement with estimates from other methods. In NGC 2808, there is evidence that a high helium abundance of Y ~ 0.4 is required to explain the periods of several of the LPVs. Conclusions: It would be interesting to determine periods for LPVs in other Galactic globular clusters where a helium abundance variation is suspected to see if the completely independent test for a high helium abundance provided by the LPVs can confirm the high helium abundance estimates.

Lebzelter, T.; Wood, P. R.

2011-05-01

119

FTO genotype is associated with phenotypic variability of body mass index  

PubMed Central

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

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

2013-01-01

120

Sudden loss of mass from a binary gravitating system  

NASA Technical Reports Server (NTRS)

Mitalas's (1980) study is generalized to treat sudden mass loss from a binary syste in an originally elliptical orbit. The orbits are characterized by angular momentum and energy, and it is shown that none of the changes in the relative orbit depends on which object it is that loses part of its mass. It is pointed out that, in principle, each could lose a different fraction. Time averages are introduced so that the orbital changes, which depend on where in orbit the mass loss takes place, can be suitably averaged over a statistical ensemble of initial systems. Even though many results that appear to be new are presented, it is noted that the main thrust is to choose and manipulate variables yielding the greatest economy of description and the greatest power of computation. Graphs are included showing the fraction of systems that on the average will be disrupted, the mean orbital changes for the survivors, and the extreme limits for the change in eccentricity.

Noerdlinger, P. D.

1982-01-01

121

Non-vacuum cosmological solutions of 5D variable mass theory of gravity  

NASA Astrophysics Data System (ADS)

A class of non-vacuum expanding cosmological solutions of Wesson's five-dimensional (5D) theory of gravity with variable rest mass is derived. The models are spatially homogeneous and isotopic and the source of gravitation is a pressureless fluid (dust) plus a cosmological constant term. The general and unified solution is found for the equations and some properties of different limiting cases are studied. Particularly, it is shown that for null cosmological constant the predicted age of the universe is smaller than the ones of the 4D Flat Robertson-Walker (FRW) models.

Carvalho, J. C.; Lima, J. A. S.; Nelson, O. R.

1994-05-01

122

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

123

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

NASA Astrophysics Data System (ADS)

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

?tefan, Sabina; Roman, Iuliana

2015-01-01

124

A new line element derived from the variable rest mass in gravitational field  

E-print Network

This paper presents a new line element based on the assumption of the variable rest mass in gravitational field, and explores some its implications. This line element is not a vacuum solution of Einstein's equations, yet it is sufficiently close to Schwarzschild's line element to be compatible with all of the experimental and observational measurements made so far to confirm the three Einstein's predictions. The theory allows radiation and fast particles to escape from all massive bodies, even from those that in Einstein's general relativity framework will be black holes. The striking feature of this line element is the non-existence of black holes.

N. Ben-Amots

2008-08-19

125

How Evolved are the Mass Donor Stars inCataclysmic Variables?  

E-print Network

Recent spectroscopic observations have identified several cataclysmic variables non-solar metal abundances. We present theoretical models which examine the level of core evolution expected for CV secondaries prior to contact. Our results indicate that few secondary stars evolve past 10% of their main sequence lifetime prior to the initiation of mass transfer; a result which is in agreement with present day observations. Thus, the non-solar metal abundances observed must be due to nuclear burning by-products accreted by the secondary star during common envelope sweeping prior to initial contact or ejecta collected during classical nova outbursts.

Steve B. Howell

2001-06-12

126

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

127

Low-Cost Automated Variable Star Detection System  

NASA Astrophysics Data System (ADS)

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

Meades, Marin Nicole; Paust, Nathaniel

2015-01-01

128

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

129

Stability theorems for multidimensional linear systems with variable parameters  

NASA Technical Reports Server (NTRS)

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

Shrivastava, S. K.

1981-01-01

130

Untangling complex dynamical systems via derivative-variable correlations  

NASA Astrophysics Data System (ADS)

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

Levnaji, Zoran; Pikovsky, Arkady

2014-05-01

131

A VARIABLE FLOW CONTROL SYSTEM FOR SUBSURFACE DRIP IRRIGATION*  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

132

An Optical Disk Jukebox Mass Memory System  

NASA Astrophysics Data System (ADS)

An optical disk "jukebox" mass memory system is being developed which will provide automatic access to any data in a store of 1013 bits within five seconds. This system contains a library of 128 optical disks with mechanisms for retrieving any disk, loading it onto a turntable, and recording or playing digital data at a rate of 50 Mb/s. The optical disks are housed in protective cartridges to facilitate handling by both the operating personnel and automatic disk handling mechanisms. Cartridges are moved from the store to a load station by a precision, belt-driven X-Y transport mechanism. The load station then mounts the disks onto a precision turntable where they are spun up to speed while still housed within their protective cartridges. Next, data is recorded or played back on these disks using focused laser beams. Finally, the disk is stopped and returned to its storage location so that the system can handle a new request. The disk handling mechanisms were designed to minimize mechanical shock and vibration while providing a rapid, smooth operation. A special centering hub design for the turntable minimizes disk eccentricities during multiple load/unload cycles and allows easy inter-changeability from machine to machine. This paper will describe the system, subsystem, and mechanism designs that were used in developing an engineering model of this jukebox concept. Test results from this engineering model will also be presented in this paper.

Ammon, G. J.

1983-11-01

133

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

134

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

NASA Astrophysics Data System (ADS)

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

Tombleson, Ryan; Smith, Nathan

2015-01-01

135

Control of a Unified Chaotic System via Single Variable Feedback  

NASA Astrophysics Data System (ADS)

Based on the LaSalle invariance principle, we propose a simple adaptive-feedback for controlling the unified chaotic system. We show explicitly with numerical proofs that our method can easily achieve the control of chaos in the unified chaotic system using only a single variable feedback. The present controller, to our knowledge, is the simplest control scheme for controlling a unified chaotic system.

Guo, Rong-Wei; Vincent E., U.

2009-09-01

136

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

137

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

138

Solving Systems of Linear Equations in Two Variables  

NSDL National Science Digital Library

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

Seward, Kim; Puckett, Jennifer

2008-01-01

139

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

140

Mass Transfer and Tidal Dynamics in White Dwarf Binary Systems  

NASA Astrophysics Data System (ADS)

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

Gerber, Jeffrey; Fuller, J.

2014-01-01

141

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

142

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

143

Variability of Mass Dependence of Auroral Acceleration Processes with Solar Activity  

NASA Technical Reports Server (NTRS)

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

Ghielmetti, Arthur G.

1997-01-01

144

Mass Uncertainty and Application For Space Systems  

NASA Technical Reports Server (NTRS)

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

Beech, Geoffrey

2013-01-01

145

Rapid multiperiodic variability in a high-mass X-ray binary  

E-print Network

Positions of High-Mass X-ray Binaries are often known precisely enough to unambiguously identify the optical component, and a number of those stars are monitored by the OGLE and MACHO collaborations. The light curves of two such candidates are examined for evidence of Be star behavior and for periodicity. One of the stars exhibits two periods of 6.833 and 15.586 hours, much shorter and more stable than periods of Be/X-Ray Binaries that are attributed to the Be star's disk, but consistent with short-term Be variability attributed to pulsations. The multiperiodicity is quantified with Fourier techniques and examined for phase stability; a combination of radial and non-radial pulsations is discussed.

Daniel Fabrycky

2004-07-29

146

Extremal entanglement and mixedness in continuous variable systems  

Microsoft Academic Search

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

Gerardo Adesso; Alessio Serafini; Fabrizio Illuminati

2004-01-01

147

Quantification and Scaling of Multipartite Entanglement in Continuous Variable Systems  

Microsoft Academic Search

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

Gerardo Adesso; Alessio Serafini; Fabrizio Illuminati

2004-01-01

148

Selecting control and balancing valves in a variable flow system  

SciTech Connect

This article describes the design and selection of control and balancing valves in a hydronic variable flow system consisting of 100 load terminals for providing cooling to a building. The author addresses approaching a linear terminal emission over the valve operating range, minimizing pump head and operating horsepower, proportioning the flow to each terminal and zone, balancing tests, and instrumentation.

Hegberg, R.A.

1997-06-01

149

Variable neural adaptive robust output feedback control of uncertain systems  

Microsoft Academic Search

The design of an adaptive robust output feedback controller is presented for a class of multi-input multi-output uncertain systems. The proposed output feedback controller uses a variable-structure radial basis function (RBF) network to approximate unknown system dynamics. The output feedback implementation is realized employing a high-gain observer. The structure variation of the RBF network is taken into account in the

Jianming Lian; Wei Zhang; Jianghai Hu; S. H. Zak

2010-01-01

150

Variable-reluctance generators in wind-energy systems  

Microsoft Academic Search

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

David A. Torrey

1993-01-01

151

Mass Distribution and Mass Transport in the Earth System: Recent Scientific Progress Due to Interdisciplinary Research  

NASA Astrophysics Data System (ADS)

This Special Issue on "Mass Distribution and Mass Transport in the Earth System: Recent Scientific Progress due to Interdisciplinary Research" reports a number of findings resulting from a collaborative effort run from 2006 until 2013, in the framework of the DFG Priority Program 1257 "Mass Distribution and Mass Transport in the Earth System". Contributions have been arranged along five lines, i.e. (1) improvements in geodesy: satellite mass monitoring through gravimetry and altimetry, (2) applications in large-scale hydrology, (3) applications in solid Earth research, (4) applications in cryospheric research, (5) applications in ocean sciences.

Kusche, Jürgen; Klemann, Volker; Sneeuw, Nico

2014-11-01

152

Synchronization between variable time delayed systems and cryptography  

E-print Network

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

Dibakar Ghosh; Santo Banerjee; A. Roy Chowdhury

2008-02-06

153

Hydraulic control system for continuously variable V-belt transmission  

SciTech Connect

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

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

1986-04-29

154

Reconstructing the dynamics of unobserved variables in spatially extended systems  

PubMed Central

Attractor reconstruction using embedding techniques is a widely used tool when analysing data from real systems. It allows reconstruction of the system dynamics from only one observable and is thus extremely powerful. We show here that this reconstruction is also possible from spatially coupled systems. We use a common host–parasitoid model as an example as ecological systems are virtually always spatially extended. Additionally, data from ecological systems has often only one observable, e.g. population density, from a potentially much higher-dimensional system. Singular value decomposition is used to show the existence of a functional relationship mapping the time delayed coordinates of one variable to the full spatially coupled system. We investigate the effects of noise and indicate two important spatial scales. Finally, we illustrate that a reconstruction can be obtained from a system that is only partially sampled.

Wilson, H. B.; Rand, D. A.

1997-01-01

155

Seasonal variability of black carbon mass in the tropical tropopause layer  

NASA Astrophysics Data System (ADS)

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

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

2011-05-01

156

Variable stiffness and damping suspension system for train  

NASA Astrophysics Data System (ADS)

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

Sun, Shuaishuai; Deng, Huaxia; Li, Weihua

2014-03-01

157

Dynamical constraints on the component masses of the cataclysmic variable WZ Sge  

E-print Network

We present phase-resolved spectroscopy of the short period cataclysmic variable WZ Sge obtained with the Hubble Space Telescope. We were able to resolve the orbital motion of a number of absorption lines that likely probe the environment near the accreting white dwarf. The radial velocities derived from simultaneous fits to 13 absorption lines indicate an orbital velocity semi-amplitude of K_UV = 47 +/- 3 km/s. However, we find that the phase zero is offset from the white dwarf ephemeris by +0.1. Our offset and velocity amplitude are very similar to constraints derived from optical emission lines from the quiescent accretion disk, despite the fact that we are probing material much closer to the primary. If we associate the UV amplitude with K_1, our dynamical constraints together with the K_2 estimates from Steeghs et al. (2001) and the known binary inclination of i=77+/-2 imply 0.88mass of the primary of M_1=0.85+/-0.04 M_sun when coupled with a mass-radius relation. Our primary mass estimates are in excellent agreement and are also self-consistent with spectrophotometric fits to the UV fluxes despite the observed phase offset. It is at this point unclear what causes the observed phase-offset in the UV spectra and by how much it distorts the radial velocity signature from the underlying white dwarf.

D. Steeghs; S. Howell; C. Knigge; B. Gaensicke; E. Sion; W. Welsh

2007-06-07

158

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

159

Double-detonation model of type Ia supernovae with a variable helium layer ignition mass  

NASA Astrophysics Data System (ADS)

Although Type Ia supernovae (SNe Ia) play an important role in the study of cosmology, their progenitors are still poorly understood. Thermonuclear explosions from the helium double-detonation sub-Chandrasekhar mass model have been considered as an alternative method for producing SNe Ia. By adopting the assumption that a double detonation occurs when a He layer with a critical ignition mass accumulates on the surface of a carbon—oxygen white dwarf (CO WD), we perform detailed binary evolution calculations for the He double-detonation model, in which a He layer from a He star accumulates on a CO WD. According to these calculations, we obtain the initial parameter spaces for SNe Ia in the orbital period and secondary mass plane for various initial WD masses. We implement these results into a detailed binary population synthesis approach to calculate SN Ia birthrates and delay times. From this model, the SN Ia birthrate in our Galaxy is ~0.4 - 1.6 × 10-3 yr-1. This indicates that the double-detonation model only produces part of the SNe Ia. The delay times from this model are ~ 70 - 710 Myr, which contribute to the young population of SNe Ia in the observations. We found that the CO WD + sdB star system CD-30 11223 could produce an SN Ia via the double-detonation model in its future evolution.

Zhou, Wei-Hong; Wang, Bo; Zhao, Gang

2014-09-01

160

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

161

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

NASA Technical Reports Server (NTRS)

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

Hord, Richard A.; Durling, Barbara J.

1961-01-01

162

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

163

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

NASA Astrophysics Data System (ADS)

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

Giacchè, S.; Gilli, R.; Titarchuk, L.

2014-02-01

164

Effect of variable body mass on plantar foot pressure and off-loading device efficacy.  

PubMed

An increasing body of evidence has implicated obesity as having a negative effect on the development, treatment, and outcome of lower extremity pathologic entities, including diabetic foot disease. The objective of the present study was to increase the body of knowledge with respect to the effects of obesity on foot function. Specifically, we attempted to (1) describe the relationship between an increasing body mass index (BMI) on plantar foot pressures during gait, and (2) evaluate the efficacy of commonly prescribed off-loading devices with an increasing BMI. A repeated measures design was used to compare the peak plantar foot pressures under multiple test conditions, with the volunteers acting as their own controls. The primary outcome measure was the mean peak plantar pressure in the heel, midfoot, forefoot, and first metatarsal, and the 2 variables were modification of patient weight (from "normal" BMI to "overweight," "obese," and "morbidly obese") and footwear (from an athletic sneaker to a surgical shoe, controlled ankle motion walker, and total contact cast). Statistically significant increases in the peak plantar pressures were observed with increasing volunteer BMI weight class, regardless of the off-loading device used. The present investigation has provided unique and specific data with respect to the changes that occur in the peak plantar pressures with variable BMIs across different anatomic levels and with commonly used off-loading devices. From our results, we have concluded that although the plantar pressures increase with increasing weight, it appears that at least some reduction in pressure can be achieved with an off-loading device, most effectively with the total contact cast, regardless of the patient's BMI. PMID:24735742

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

2014-01-01

165

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

166

Quantification and scaling of multipartite entanglement in continuous variable systems.  

PubMed

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

Adesso, Gerardo; Serafini, Alessio; Illuminati, Fabrizio

2004-11-26

167

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

168

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

169

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

SciTech Connect

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

Riaz, B.; Martin, E. L.; Bouy, H. [Instituto de Astrof'sica de Canarias, E38205 La Laguna, Tenerife (Spain); Tata, R. [University of Central Florida, Department of Physics, P.O. Box 162385, Orlando, FL 32816-2385 (United States)], E-mail: basmah@iac.es

2009-08-01

170

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

171

Wearable depression monitoring system with heart-rate variability.  

PubMed

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

Roh, Taehwan; Sunjoo Hong; Hoi-Jun Yoo

2014-08-01

172

Modeling Mass in the Solar System and a Galaxy  

NSDL National Science Digital Library

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

173

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

PubMed Central

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

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

2009-01-01

174

Performance of Thermal Mass Flow Meters in a Variable Gravitational Environment  

NASA Technical Reports Server (NTRS)

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

Brooker, John E.; Ruff, Gary A.

2004-01-01

175

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

176

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

PubMed

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

Rühli, Frank; Henneberg, Maciej; Woitek, Ulrich

2008-12-01

177

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

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

178

Electrical transmission system with variable frequency through long length cable  

SciTech Connect

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

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

1996-12-31

179

Extremal entanglement and mixedness in continuous variable systems  

SciTech Connect

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

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

2004-08-01

180

Two-Stage Variable Sample-Rate Conversion System  

NASA Technical Reports Server (NTRS)

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

Tkacenko, Andre

2009-01-01

181

Realtime Multichannel System for Beat to Beat QT Interval Variability  

NASA Technical Reports Server (NTRS)

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

Starc, Vito; Schlegel, Todd T.

2006-01-01

182

Variability of Carbon-IV Emission and Multi-Epoch Virial Mass Estimation in High-Redshift Quasars  

NASA Astrophysics Data System (ADS)

The CIV emission line in quasar spectra is well-known to show systematic blue-shifts often attributed to accretion disk winds. We investigate the variability of the CIV line properties in a large sample of multi-epoch quasar observations from the SDSS DR11 BOSS survey, focusing on potential correlations of the blueshift variability with line and continuum properties. Preliminary findings show very weak to no variability in the blue-shifting of the region of interest and weak correlation between line blue-shift and change in continuum flux between epochs, indicating near constant outflow speeds. We will also continue to investigate the use of multiple epoch luminosities of the CIV line as a probe of virial mass of the host SMBH. By recalibrating estimates built on the use of single epoch data and correcting for any changes in outflow speed, it is hoped to more finely tune BH mass estimates.

Sharma, Ramon; Ruan, John J.

2015-01-01

183

Improvements in Dynamic Characteristics of Automobile Suspension Systems Part 1. Two-Mass Systems  

Microsoft Academic Search

In a previous paper, [3] the random vibrations of simple linear models of automobile suspension were solved with respect to seat elasticity and human sensitivity to vibrations. The present study uses more realistic linear models taking into account the unsprung mass.Two configurations of masses are investigated: a two-mass system consisting of a sprung mass and an unsprung mass, and a

D. RYBA

1974-01-01

184

Variability of the Spin Period of the White Dwarf in the Intermediate Polar V405 Aur: Low-Mass Third Body or Precession ?  

E-print Network

We present the results of photometric CCD observations of the magnetic cataclysmic variable V405 Aurigae (RX J0558.0+5353 = 1RXS J055800.7+535358) obtained using different instruments. We analysed variability of the spin period of the white dwarf in the V405 Aur (RX J0558.0+5353) system using our observations and previously published maxima timings. The spin period of the system in 2010-2012 is $P=545.4558163(94)$s. As we have gaps in observational data, we present 2 hypotheses of the spin period variability of this system - a cubic ephemeris which may be interpreted by a precession of the magnetic white dwarf or a periodic change with a period of 6.2 years and semi-amplitude of $17.2\\pm1.8$ sec. The periodic variations may be interpreted by a light-time effect caused by a low-mass star ($M_3\\ge0.09M_\\odot$). In this case, the system belongs to a rare class of cataclysmic variables with a third body.

Breus, V V; Dubovsky, P; Kolesnikov, S V; Zhuzhulina, E A; Hegedus, T; Beringer, P; Petrik, K; Robertson, J W; Kudzej, I; Shakhovskoy, N M

2013-01-01

185

MEASURING THE MASS OF SOLAR SYSTEM PLANETS USING PULSAR TIMING  

SciTech Connect

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

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

2010-09-10

186

VX Her: Eclipsing Binary System or Single Variable Star  

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

187

Year-to-year variability in haemoglobin mass response to two altitude training camps  

PubMed Central

Aim To quantify the year-to-year variability of altitude-induced changes in haemoglobin mass (Hbmass) in elite team-sport athletes. Methods 12 Australian-Footballers completed a 19-day (ALT1) and 18-day (ALT2) moderate altitude (?2100?m), training camp separated by 12?months. An additional 20 participants completed only one of the two training camps (ALT1 additional n=9, ALT2 additional n=11). Total Hbmass was assessed using carbon monoxide rebreathing before (PRE), after (POST1) and 4?weeks after each camp. The typical error of Hbmass for the pooled data of all 32 participants was 2.6%. A contemporary statistics analysis was used with the smallest worthwhile change set to 2% for Hbmass. Results POST1 Hbmass was very likely increased in ALT1 (3.6±1.6%, n=19; mean±?90 CL) as well as ALT2 (4.4±1.3%, n=23) with an individual responsiveness of 1.3% and 2.2%, respectively. There was a small correlation between ALT1 and ALT2 (R=0.21, p=0.59) for a change in Hbmass, but a moderately inverse relationship between the change in Hbmass and initial relative Hbmass (g/kg (R=?0.51, p=0.04)). Conclusions Two preseason moderate altitude camps 1?year apart yielded a similar (4%) mean increase in Hbmass of elite footballers, with an individual responsiveness of approximately half the group mean effect, indicating that most players gained benefit. Nevertheless, the same individuals generally did not change their Hbmass consistently from year to year. Thus, a ‘responder’ or ‘non-responder’ to altitude for Hbmass does not appear to be a fixed trait. PMID:24282208

McLean, Blake D; Buttifant, David; Gore, Christopher J; White, Kevin; Kemp, Justin

2013-01-01

188

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

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

189

An extrasolar planetary system with three Neptune-mass planets  

Microsoft Academic Search

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

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

2006-01-01

190

Low-Mass Inflation Systems for Inflatable Structures  

NASA Technical Reports Server (NTRS)

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

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

1995-01-01

191

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

192

Compressive mass analysis on quadrupole ion trap systems.  

PubMed

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

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

2014-07-01

193

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

194

Balloon borne optical disk mass storage system  

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

195

Using GRACE measurements of time variable gravity, elevation changes from ICESat, OIB and ENVISAT and surface mass balance outputs from RACMO to improve ice mass balance estimates  

NASA Astrophysics Data System (ADS)

The glacial isostatic adjustment (GIA) correction represents a source of uncertainty for ice sheet mass balance estimates from the Gravity Recovery and Climate Experiment (GRACE) time variable gravity measurements. We evaluate Greenland and Antarctic GIA corrections by comparing the spatial patterns of GRACE-derived ice mass trends corrected for glacial isostatic adjustment with volume changes from ICESat (Ice, Cloud, and Land Elevation Satellite), OIB (Operation IceBridge) and ENVISAT altimetry missions, and surface mass balance (SMB) products from the Regional Atmospheric Climate Model (RACMO). We show that using the spatial and temporal characteristics of the different contributions to the ice mass balance estimates that it is possible to evaluate different GIA corrections. In Greenland, the GRACE ice mass changes obtained using the Simpson et al. (2009) and Geruo et al. (2013) GIA corrections show good agreement in the spatial patterns and amplitude. The GRACE estimate corrected using the Wu et al. (2010) GIA shows similar spatial patterns to the other two, but produces an average ice mass loss for the entire ice sheet that is 50% smaller. In Antarctica, the total magnitude and spatial structure of the GRACE-estimated ice mass change is highly dependent on the GIA correction. In key basins of East Antarctica, the interpretation of regional ice mass changes can reflect the GIA model selection as the ice mass to GIA signal ratio is smaller. We apply the same methodology used for the Greenland ice sheet in Antarctica to evaluate the different GIA corrections and check for consistency between the different techniques at a regional scale.

Sutterley, T. C.; Velicogna, I.; Csatho, B. M.; van den Broeke, M. R.; Wahr, J. M.; Flament, T.; Rezvan-Behbahani, S.; Babonis, G. S.; A, G.

2013-12-01

196

GROUNDWATER MASS TRANSPORT AND EQUILIBRIUM CHEMISTRY MODEL FOR MULTICOMPONENT SYSTEMS  

EPA Science Inventory

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

197

Variability in the cardiac venous system of wistar rats.  

PubMed

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

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

2015-01-01

198

NASA Langley Research Center's distributed mass storage system  

NASA Technical Reports Server (NTRS)

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

Pao, Juliet Z.; Humes, D. Creig

1993-01-01

199

Concepts for Variable/Multi-Speed Rotorcraft Drive System  

NASA Technical Reports Server (NTRS)

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

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

2008-01-01

200

Transmission ratio control system for a continuously variable transmission  

SciTech Connect

This patent describes a control system for a continuously variable transmission for transmitting power of an internal combustion engine controlled by an accelerator pedal, the transmission comprising a drive pulley having a hydraulically shiftable first disc and a first hydraulic cylinder for operating the disc, a driven pulley having a hydraulically shiftable second disc and a second hydraulic cylinder for operating the second disc, and a belt engaged with both pulleys, the control system including a first hydraulic circuit having a pump for supplying oil to both of the hydraulic cylinders, a transmission ratio control valve having a spool for controlling the oil supplied to the first hydraulic cylinder of the drive pulley, shifting means for shifting the spool, sensing means for sensing operating conditions of the engine and the transmission, actual transmission ratio producing means responsive to the sensed operating conditions for producing means responsive to the sensed signal representing the actual transmission ratio of the transmission.

Miyawaki, M

1989-05-23

201

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

NASA Technical Reports Server (NTRS)

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

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

1984-01-01

202

Mass storage system reference model, Version 4  

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

203

Ages of the universe for FRW-type models in Wesson's 5D variable mass theory of gravity  

NASA Astrophysics Data System (ADS)

The age of the universe is computed for spatially homogeneous and isotropic cosmological models of the relativistic Wesson's 5D variable mass theory of gravity. It is shown that if the pressure in the mass dimension is negligible, ages old enough to agree with the observations can only be obtained if the cosmological constant is different from zero. In addition, unlike the standard Friedmann-Robertson-Walker (FRW) models in Einstein's 4D theory, the age value itself is not affected by the nature of the matter content (matter and radiation dominated models give the same age).

Lima, J. A. S.; Carvalho, J. C.; Nelson, O. R.

1994-09-01

204

21 CFR 866.6050 - Ovarian adnexal mass assessment score test system.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Ovarian adnexal mass assessment score test system. 866...Systems § 866.6050 Ovarian adnexal mass assessment score test system. (a) Identification. An ovarian/adnexal mass assessment test system is a device...

2011-04-01

205

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

206

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

207

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

208

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

209

Prediction of segmental lean mass using anthropometric variables in young adults  

Microsoft Academic Search

The aim of the present study was to develop and cross-validate anthropometrical prediction equations for segmental lean tissue mass (SLM). One hundred and seventeen young healthy Caucasians (67 men and 50 women; mean age: 31.9 ± 10.0 years; Body Mass Index: 24.3 ± 3.2 kg · m) were included. Body mass (BM), stretch stature (SS), 14 circumferences (CC), 13 skinfolds (SF) and 4 bone breadths (BB) were

Aldo Scafoglieri; Jonathan Tresignie; Steven Provyn; Mike Marfell-jones; Thomas Reilly; Ivan Bautmans; Jan Pieter Clarys

2012-01-01

210

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

NASA Astrophysics Data System (ADS)

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

Özdönmez, A.; Ak, T.; Bilir, S.

2015-01-01

211

Optimization of neural networks using variable structure systems.  

PubMed

This paper proposes a new mixed training algorithm consisting of error backpropagation (EBP) and variable structure systems (VSSs) to optimize parameter updating of neural networks. For the optimization of the number of neurons in the hidden layer, a new term based on the output of the hidden layer is added to the cost function as a penalty term to make optimal use of hidden units related to weights corresponding to each unit in the hidden layer. VSS is used to control the dynamic model of the training process, whereas EBP attempts to minimize the cost function. In addition to the analysis of the imposed dynamics of the EBP technique, the global stability of the mixed training methodology and constraints on the design parameters are considered. The advantages of the proposed technique are guaranteed convergence, improved robustness, and lower sensitivity to initial weights of the neural network. PMID:22665508

Mohseni, Seyed Alireza; Tan, Ai Hui

2012-12-01

212

Electromagnetic variable degrees of freedom actuator systems and methods  

DOEpatents

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

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

2009-02-17

213

Adaptive mass expulsion attitude control system  

NASA Technical Reports Server (NTRS)

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

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

2001-01-01

214

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

SciTech Connect

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

Hays, Lance G

2014-07-07

215

Goddard Conference on Mass Storage Systems and Technologies, volume 2  

NASA Technical Reports Server (NTRS)

Papers and viewgraphs from the conference are presented. Discussion topics include the IEEE Mass Storage System Reference Model, data archiving standards, high-performance storage devices, magnetic and magneto-optic storage systems, magnetic and optical recording technologies, high-performance helical scan recording systems, and low end helical scan tape drives. Additional discussion topics addressed the evolution of the identifiable unit for processing (file, granule, data set, or some similar object) as data ingestion rates increase dramatically, and the present state of the art in mass storage technology.

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

1993-01-01

216

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

NASA Technical Reports Server (NTRS)

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

Lekashman, John

1998-01-01

217

Design and Manufacturing of Extremely Low Mass Flight Systems  

NASA Technical Reports Server (NTRS)

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

Johnson, Michael R.

2002-01-01

218

EVALUATION OF A SULFUR DIOXIDE MASS EMISSION RATE MONITORING SYSTEM  

EPA Science Inventory

An evaluation was conducted to determine the capabilities and limitations of a commercially available monitoring system that provides sulfur dioxide mass emission rate data as a direct output. The monitoring system was operated continuously for extended periods at a coal-fired po...

219

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

220

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

221

How does variability of immune system genes affect placentation?  

PubMed Central

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

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

2011-01-01

222

Transmission ratio control system for a continuously variable transmission  

SciTech Connect

This patent describes a control system for a continuously variable transmission for transmitting the power of an internal combustion engine to driving wheels of a motor vehicle through a clutch, having a drive pulley including a hydraulically shiftable disc and a first hydraulic cylinder for shifting the disc. A driven pulley includes a hydraulically shiftable disc and a second hydraulic cylinder for operating the disc of the driven pulley. A belt is engaged with both pulleys. A transmission ratio control valve has ports and a spool and a line pressure control valve has ports and a spool. A first hydraulic circuit has a pump for supplying oil to the first and second cylinders through the line pressure control valve which controls line pressure and the transmission ratio control valve. The system comprises: detecting means for detecting load on the engine and for producing a load signal; first means responsive to the load signal for producing a desired line pressure signal; second means responsive to the desired line pressure signal for shifting the spool of the line pressure control valve so as to provide control the line pressure; detecting means for detecting a stop of the vehicle and producing a stop signal; third means responsive to the stop signal for increasing the line pressure so as to operate the second hydraulic cylinder to increase the transmission ratio.

Morimoto, Y.; Tezuka, K.

1987-11-24

223

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

Microsoft Academic Search

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

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

2006-01-01

224

6-year periodicity and variable synchronicity in a mass-flowering plant.  

PubMed

Periodical organisms, such as bamboos and periodical cicadas, are very famous for their synchronous reproduction. In bamboos and other periodical plants, the synchronicity of mass-flowering and withering has been often reported indicating these species are monocarpic (semelparous) species. Therefore, synchronicity and periodicity are often suspected to be fairly tightly coupled traits in these periodical plants. We investigate the periodicity and synchronicity of Strobilanthes flexicaulis, and a closely related species S. tashiroi on Okinawa Island, Japan. The genus Strobilanthes is known for several periodical species. Based on 32-year observational data, we confirmed that S. flexicaulis is 6-year periodical mass-flowering monocarpic plant. All the flowering plants had died after flowering. In contrast, we found that S. tashiroi is a polycarpic perennial with no mass-flowering from three-year individual tracking. We also surveyed six local populations of S. flexicaulis and found variation in the synchronicity from four highly synchronized populations (>98% of plants flowering in the mass year) to two less synchronized one with 11-47% of plants flowering before and after the mass year. This result might imply that synchrony may be selected for when periodicity is established in monocarpic species. We found the selective advantages for mass-flowering in pollinator activities and predator satiation. The current results suggest that the periodical S. flexicaulis might have evolved periodicity from a non-periodical close relative. The current report should become a key finding for understanding the evolution of periodical plants. PMID:22163279

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

2011-01-01

225

The chemical evolution of galaxies with a variable integrated galactic initial mass function  

NASA Astrophysics Data System (ADS)

Standard analytical chemical evolution modelling of galaxies has been assuming the stellar initial mass function (IMF) to be invariant and fully sampled allowing fractions of massive stars to contribute even in dwarf galaxies with very low star formation rates (SFRs). Recent observations show the integrated galactic initial mass function (IGIMF) of stars, i.e. the galaxy-wide IMF, to become systematically top-heavy with increasing SFR. This has been predicted by the IGIMF theory, which is here used to develop the analytical theory of the chemical evolution of galaxies. This theory is non-linear and requires the iterative solution of implicit integral equations due to the dependence of the IGIMF on the metallicity and on the SFR. It is shown that the mass-metallicity relation of galaxies emerges naturally, although at low masses the theoretical predictions overestimate the observations by 0.3-0.4 dex. Good agreement with the observation can be obtained only if gas flows are taken into account. In particular, we are able to reproduce the mass-metallicity relation observed by Lee et al. with modest amounts of infall and with an outflow rate which decreases as a function of the galactic mass. The outflow rates required to fit the data are considerably smaller than required in models with invariant IMFs.

Recchi, S.; Kroupa, P.

2015-02-01

226

Performance evaluation of mass storage systems for scientific databases  

SciTech Connect

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

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

1994-09-01

227

Spectral variability of the ? Sco AB binary system observed with IUE  

NASA Astrophysics Data System (ADS)

We present ultraviolet spectra of the ? Sco AB binary system taken by the International Ultraviolet Explorer during the period from 1979 to 1995. An investigation is carried out on the spectral variability of Mg II k and h emission lines arising from the chromosphere of ? Sco A ( Van der Hucht et al., 1979). There are absorption and emission components on the blue sides of the Mg II k and h lines, which are formed in the cool circumstellar gas shells around two stars ( Bernat and Lambert, 1976). This work is based on calculations of line fluxes and line widths for the aforementioned spectral lines. We found that there is spectral variability for these physical parameters with pulsation phase, which we attribute to the changes of density and temperature of the chromosphere of ? Sco A as a result of the semi-regular pulsation and the variability of mass loss of the red supergiant ( Reimers et al., 2008). The observed values of the k-to-h ratio are approximately one, implying that the k and h emission lines originate from an optically thick atmosphere.

Sanad, M. R.; Bobrowsky, M.

2010-10-01

228

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

SciTech Connect

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

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

2012-07-20

229

Sliding Mode Power Control of Variable Speed Wind Energy Conversion Systems  

E-print Network

Sliding Mode Power Control of Variable Speed Wind Energy Conversion Systems B. Beltran, T. Ahmed power generation in variable speed wind energy conversion systems (VS-WECS). These systems have two variations. Index Terms--Wind energy conversion system, power generation control, sliding mode control

Boyer, Edmond

230

Dynamics of Mass Transfer in Wide Symbiotic Systems  

NASA Astrophysics Data System (ADS)

We investigate the formation of accretion disks around the secondary in detached systems consisting of an Asymptotic Giant Branch (AGB) star and a compact accreting companion as a function of mass loss rate and orbital parameters. In particular, we study winds from late-type stars that are gravitationally focused by a companion in a wide binary system using hydrodynamical simulations. For a typical slow and massive wind from an evolved star there is a stream flow between the stars with accretion rates of a few percent of the mass loss from the primary. Mass transfer through a focused wind is an important mechanism for a broad range of interacting binary systems and can explain the formation of Barium stars and other chemically peculiar stars.

de Val-Borro, Miguel; Karovska, M.; Sasselov, D.

2010-01-01

231

Effects of NCG Charging Mass on the Operational Characteristics of Variable Conductance Heat Pipe  

Microsoft Academic Search

Numerical analysis and experimental study are performed to investigate the effect of heat load and operating temperature on the thermal performance of several variable conductance heat pipe heat pipe (VCHP) with screen meshed wick. The heat pipe is designed in 200 screen meshes, 500 ? length and 12.7 ? outer diameter tube of copper, water (4.8 g) is used as

JEONG SE SUH; YOUNG SIK PARK; KYUNG TAEK CHUNG; CHANG HO KANG

232

Etude Numérique d'un Jet Plan à Masse Volumique Variable en Régime Laminaire  

Microsoft Academic Search

A finite difference scheme is used to solve equations governing variable density isotherm laminar plane jet. Results gotten for different gases ejected to the exit of the nozzle, permitted us to study the influence of the initial density ratio w ( 01 w ?? =?) on the characteristic moments of the jet in a large range ( 23 . 7

W. Kriaa; H. Mhiri; S. El Golli

2002-01-01

233

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

234

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

235

Hydraulic line pressure control system for an infinitely variable transmission  

SciTech Connect

An improved control system is described for an infinitely variable transmission for transmitting the power of an internal combustion engine mounted on a vehicle. The transmission comprises: a primary pulley having a hydraulically shiftable disc and a hydraulic cylinder for shifting the disc, a secondary pulley having a hydraulically shiftable disc and a hydraulic cylinder for operating the disc, a belt engaged with both pulleys, and a hydraulic circuit having a pump for supplying oil. It also comprises: a transmission ratio control valve responsive to engine speed for controlling the oil and for shifting the disc of the primary pulley to change the transmission ratio, and a pressure regulator valve responsive to the transmission ratio for increasing the line pressure of the hydraulic circuit with increase of the transmission ratio. The improvement described here comprises: first means comprising a throttle position sensor for detecting the torque of the engine and an electronic circuit responsive to an output signal of the throttle position sensor for producing a control signal proportional to the torque; and second means responsive to the control signal for operating the pressure regulator valve so as to increase the line pressure with increase of the torque.

Sakai, Y.

1987-01-27

236

Dust composition and mass-loss return from the luminous blue variable R71 in the LMC  

NASA Astrophysics Data System (ADS)

Context. We present an analysis of mid- and far-infrared (IR) spectrum and spectral energy distribution (SED) of the luminous blue variable (LBV) R71 in the Large Magellanic Cloud (LMC). Aims: This work aims to understand the overall contribution of high-mass LBVs to the total dust-mass budget of the interstellar medium (ISM) of the LMC and compare this with the contribution from low-mass asymptotic giant branch (AGB) stars. As a case study, we analyze the SED of R71. Methods: We compiled all the available photometric and spectroscopic observational fluxes from various telescopes for a wide wavelength range (0.36-250 ?m). We determined the dust composition from the spectroscopic data, and derived the ejected dust mass, dust mass-loss rate, and other dust shell properties by modeling the SED of R71. We noted nine spectral features in the dust shell of R71 by analyzing Spitzer Space Telescope spectroscopic data. Among these, we identified three new crystalline silicate features. We computed our model spectrum by using 3D radiative transfer code MCMax. Results: Our model calculation shows that dust is dominated by amorphous silicates, with some crystalline silicates, metallic iron, and a very tiny amount of polycyclic aromatic hydrocarbon (PAH) molecules. The presence of both silicates and PAHs indicates that the dust has a mixed chemistry. We derived a dust mass of 0.01 M?, from which we arrive at a total ejected mass of ?5 M?. This implies a time-averaged dust mass-loss rate of 2.5 × 10-6 M? yr-1 with an explosion about 4000 years ago. We assume that the other five confirmed dusty LBVs in the LMC loose mass at a similar rate, and estimate the total contribution to the mass budget of the LMC to be ?10-5 M? yr-1, which is comparable to the contribution by all the AGB stars in the LMC. Conclusions: Based on our analysis on R71, we speculate that LBVs as a class may be an important dust source in the ISM of the LMC.

Guha Niyogi, S.; Min, M.; Meixner, M.; Waters, L. B. F. M.; Seale, J.; Tielens, A. G. G. M.

2014-09-01

237

Transmission ratio control system for a continuously variable transmission  

SciTech Connect

This patent describes a control system for a continuously variable transmission for transmitting power of an internal combustion engine, the transmission having a drive pulley including a hydraulically shiftable first disc and a hydraulic cylinder for operating the disc, a driven pulley including a hydraulically shiftable second disc and a hydraulic cylinder for operating the second disc, and a belt engaged with both pulleys, the control system comprising a hydraulic circuit including a pump for supplying oil to both the hydraulic cylinders, a transmission ratio control valve including a shiftable spool for controlling the oil supplied to the cylinder of the drive pulley to change transmission ratio of the transmission to a desired transmission ratio, shifting means for shifting the spool, sensing means for sensing operating conditions of the engine and the transmission and for producing condition signals dependent on the conditions, actual transmission ratio signal producing means responsive to the condition signals for producing an actual transmission ratio signal corresponding to the actual transmission ratio of the transmission, desired transmision ratio signal producing means responsive to the condition signals for producing a desired transmission ratio signal corresponding to a desired transmission ratio, transmission ratio changing speed signal producing means responsive to the actual transmission ratio signal and to the desired transmission ratio signal for producing a transmission ratio changing rate signal corresponding to a transmission ratio changing rate, and control signal producing means responsive to the transmission ratio changing rate signal for producing a control signal for operating the shifting means to shift the spool dependent on the transmission ratio changing rate for changing the actual transmission ratio of the transmission to the desired transmission ratio.

Tanaka, H.

1989-05-30

238

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

NASA Astrophysics Data System (ADS)

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

Abe, Naoto; Nishioka, Nobuhiro

239

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

240

Primordial nucleosynthesis as a test of variable rest mass in five-dimensional cosmology  

NASA Astrophysics Data System (ADS)

The deviation of primordial helium production due to a variation in the difference between the rest masses of the nucleons is presented. An upper bound ?(Mn - Mp) <~ 0.129 MeV, between the present and nucleosynthesis epochs is found. This bound is used to analyze Wesson's theory of gravitation; as a result, it is ruled out by observation.

Anchordoqui, Luis A.; Torres, Diego F.; Vucetich, Héctor

1996-02-01

241

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

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

242

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

SciTech Connect

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

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

2013-03-10

243

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...

244

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

Microsoft Academic Search

Periodical organisms, such as bamboos and periodical cicadas, are very famous for their synchronous reproduction. In bamboos and other periodical plants, the synchronicity of mass-flowering and withering has been often reported indicating these species are monocarpic (semelparous) species. Therefore, synchronicity and periodicity are often suspected to be fairly tightly coupled traits in these periodical plants. We investigate the periodicity and

Satoshi Kakishima; Jin Yoshimura; Hiroko Murata; Jin Murata

2011-01-01

245

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

Microsoft Academic Search

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

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

2004-01-01

246

The pulsation modes and masses of carbon-rich long period variables  

Microsoft Academic Search

Following our study of the carbon-rich giants in the HR diagram and of their luminosity function (Paper III), we investigate the pulsation data of the long period variables (LPVs) included in our sample. Pulsation modes (fundamental, overtone(s)) for carbon LPVs are identified in the period-radius diagram, making use of observed bi-periodicity in a small subsample of those stars, and of

J. Bergeat; A. Knapik; B. Rutily

2002-01-01

247

High Frequency Effects of Variable Frequency Drives (VFD) on Electrical Submersible Pump (ESP) Systems  

E-print Network

Variable frequency drives (VFD) and subsea (umbilical) cables are frequently used in electrical submersible pump (ESP) systems for offshore platforms. There are two basic system configurations for ESP systems; VFD can be installed on the platform...

Ozkentli, Esra

2012-10-19

248

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

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

249

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

NASA Astrophysics Data System (ADS)

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

Velicogna, I.; Wahr, J.

2013-06-01

250

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

251

Variable sampling frequency in iterative learning current Control for Shunt Active Filter in aircraft power systems  

Microsoft Academic Search

This paper investigates the feasibility of an Iterative Leaning current Control (ILC) with variable sampling frequency to realize a 3-phase Shunt Active Filter (SAF) used for harmonic compensation in new generation aircrafts, where a Variable Speed Variable-Frequency (VSVF) power system, typically between 360 and 900Hz, is nowadays used. Due to the high supply frequency, such applications are particularly demanding for

Pericle Zanchetta; Marco Degano; Junyi Liu; Paolo Mattavelli

2011-01-01

252

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

253

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

NASA Astrophysics Data System (ADS)

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

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

2005-09-01

254

A Method to Study the Effect of Renewable Resource Variability on Power System Dynamics  

E-print Network

1 A Method to Study the Effect of Renewable Resource Variability on Power System Dynamics Yu- tricity generation on power system dynamics, with a focus on time-scales involving electromechanical of variability in renewable-based generation on power system dynamic performance, particularly, on time- scales

Liberzon, Daniel

255

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

E-print Network

Distributions and variability of particulate organic matter in a coastal upwelling system L. Karp (2004), Distributions and variability of particulate organic matter in a coastal upwelling system, J the role of coastal upwelling systems in the cycling and export of organic carbon. [3] Our current

Pierce, Stephen

256

Evaluation program for the energy-saving of variable-air-volume systems  

Microsoft Academic Search

Although variable-air-volume system (VAVS) can save much energy compared with other kind of HVAC system (e.g. constant-air-volume system (CAVS), fan-coil system (FCS)), it demands more investment. The rate of return of variable-air-volume system, which is closely related to the energy-saving rate of the system, ought to be taken into account by the engineers in the course of design. China has

Ye Yao; Zhiwei Lian; Weiwei Liu; Zhijian Hou; Ming Wu

2007-01-01

257

Dual Source Mass Spectrometer and Sample Handling System  

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

258

Advanced Life Support Equivalent System Mass Guidelines Document  

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

259

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

260

Estimation of convective mass transfer in solar distillation systems  

Microsoft Academic Search

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

Sanjay Kumar; G. N. Tiwari

1996-01-01

261

Threshold mass numerologies and resonances in Boson and Baryon systems  

Microsoft Academic Search

Some of the more remarkable features between coincidences in mass ; thresholds for production of boson and baryon resonances and resonances in the ; baryon system are re-emphasized in connection with the cusp effect. The ; discussion is confined to three-body final states. The resonances are extremely ; narrow and consistent with zero width within experimental resolution. (N.W.R.);

S. F. Tuan

1962-01-01

262

The dynamics of mass transfer in equilibrium correlated systems  

NASA Astrophysics Data System (ADS)

We present the results of a numerical simulation of Brownian motion for particles in statistically equilibrium correlated systems. A new analytical model is presented, which describes the dynamics of the mass-transfer of interacting particles, including the transition between the ballistic and diffusive regimes of motion. The calculations were performed for a wide range of parameters, corresponding to the conditions of experiments in laboratory dusty plasmas. Most attention was paid to two-dimensional correlated systems.

Vaulina, O. S.; Koss, X. G.

2013-11-01

263

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

SciTech Connect

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

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

2012-12-01

264

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

E-print Network

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

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

2012-11-14

265

Age, body mass index, race and other determinants of steroid hormone variability: the HERITAGE Family Study  

Microsoft Academic Search

Objective and methods: To investigate from the HERITAGE Family Study database, 13 steroid hormones (androstane-3a ,1 7b-diol glucuronide, androsterone glucuronide, cortisol, dehydroepiandrosterone (DHEA), DHEA ester (DHEAE), DHEA sulfate (DHEAS), dihydrotestosterone (DHT), estradiol, 17- hydroxyprogesterone, progesterone, pregnenolone ester, sex hormone binding globulin (SHBG) and testosterone in each sex for their relationships with age, body mass index (BMI), race and key lifestyle

O Ukkola; J Gagnon; T Rankinen; P A Thompson; Y Hong; A S Leon; J S Skinner; C Bouchard; Biocenter Oulu

2001-01-01

266

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

Code of Federal Regulations, 2012 CFR

...Approval of urban system nonhighway public mass transit projects. 810.308 Section 810...TRANSPORTATION PUBLIC TRANSPORTATION MASS TRANSIT AND SPECIAL USE HIGHWAY PROJECTS Federal-Aid Urban System Nonhighway Public Mass Transit Projects § 810.308 Approval...

2012-04-01

267

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

...Approval of urban system nonhighway public mass transit projects. 810.308 Section 810...TRANSPORTATION PUBLIC TRANSPORTATION MASS TRANSIT AND SPECIAL USE HIGHWAY PROJECTS Federal-Aid Urban System Nonhighway Public Mass Transit Projects § 810.308 Approval...

2014-04-01

268

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

Code of Federal Regulations, 2013 CFR

...Approval of urban system nonhighway public mass transit projects. 810.308 Section 810...TRANSPORTATION PUBLIC TRANSPORTATION MASS TRANSIT AND SPECIAL USE HIGHWAY PROJECTS Federal-Aid Urban System Nonhighway Public Mass Transit Projects § 810.308 Approval...

2013-04-01

269

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

270

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

271

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

DOEpatents

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

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

2013-10-22

272

Mechanism studies of seasonal variability of dissolved oxygen in Mass Bay: A multi-scale FVCOM/UG-RCA application  

NASA Astrophysics Data System (ADS)

Long-term (1992-2010) water quality monitoring records reveal that the dissolved oxygen (DO) concentration in Mass Bay exhibits a well-defined seasonal cycle, highest in March-April and lowest in October. This pattern persists in all years with insignificant interannual variability. A multi-domain-nested coupled physical-biogeochemical model was developed and applied to simulate the DO field over the 16-year period 1995-2010. The model-computed DO and nitrogen concentrations were in good agreement with observations. An EOF analysis of the modeled DO field indicates that DO in Mass Bay features both well-defined seasonal and spatial modes. The magnitude and phase of the DO seasonal cycle vary more significantly in the southern bay than in the northern bay. Horizontal advection, which is connected to the western Gulf of Maine coastal currents, plays a dominant role in the DO variability in the northern bay. The southern bay features a well-defined local retention mechanism with a longer residence time. In this region, the DO variation is controlled predominantly by local biogeochemical processes. Since the photosynthetic minus respiration production of DO is always balanced to a large degree by the oxidation of organic matters, reaeration becomes a major driver for the seasonal cycle of DO.

Xue, Pengfei; Chen, Changsheng; Qi, Jianhua; Beardsley, Robert C.; Tian, Rucheng; Zhao, Liuzhi; Lin, Huichan

2014-03-01

273

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. PMID:21755926

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

274

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

275

A New Rock Mass Quality Rating System: Rock Mass Quality Rating (RMQR) and Its Application to the Estimation of Geomechanical Characteristics of Rock Masses  

NASA Astrophysics Data System (ADS)

The qualitative description of rock masses by means of classification systems and subsequent correlation to establish engineering quantities or design parameters has become one of the most challenging topics in rock engineering. Many rock mass classification systems have been proposed for rock masses with the consideration of a particular rock structure and/or specific purposes. Therefore, direct utilization of these systems, in their original form, for the characterization of complex rock mass conditions is not always possible. This is probably one of the reasons why rock engineers continue to develop new systems or modify and extend current ones. The recent tendency is to obtain rock mass properties from the utilization of properties of intact rock and rock classification indexes, which have some drawbacks. In this study, it is aimed to propose a new rock mass quality rating system designated as Rock Mass Quality Rating (RMQR). This new rock mass rating system is used to estimate the geomechanical properties of rock masses. In the first part of this paper, the input parameters of RMQR and their ratings are given and discussed. In the second part, the unified formula proposed by the first author is adopted for the new rock mass rating system for estimating the rock mass properties and compared with the results of the in situ tests carried out in Japan and those estimated from some empirical relationships developed by other investigators, and the outcomes of these studies are presented and discussed.

Aydan, Ömer; Ulusay, Re?at; Tokashiki, Naohiko

2014-07-01

276

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

PubMed

Systems biology is currently making a bid to show that it is able to make an important contribution to personalised or precision medicine. In order to do so, systems biologists need to find a way of tackling the pervasive variability of biological systems that is manifested in the medical domain as inter-subject variability. This need is simultaneously social and epistemic: social as systems biologists attempt to engage with the interests and concerns of clinicians and others in applied medical research; epistemic as they attempt to develop new strategies to cope with variability in the validation of the computational models typical of systems biology. This paper describes one attempt to develop such a strategy: a trial with a population-of-models approach in the context of cardiac electrophysiology. I discuss the development of this approach against the background of ongoing tensions between mathematically and experimentally inclined modellers on the one hand, and attempts to forge new collaborations with medical scientists on the other. Apart from the scientific interest of the population-of-models approach for tackling variability, the trial also offers a good illustration of the epistemology of experiment-facing modelling. I claim that it shows the extent to which experiment-facing modelling and validation require the establishment of criteria for comparing models and experiments that enable them to be linked together. These 'grounds of comparability' are the broad framework in which validation experiments are interpreted and evaluated by all the disciplines in the collaboration, or being persuaded to participate in it. I claim that following the process of construction of the grounds of comparability allows us to see the establishment of epistemic norms for judging validation results, through a process of 'normative intra-action' (Rouse, 2002) that shape the social and epistemic evolution of systems approaches to biomedicine. PMID:25262024

Carusi, Annamaria

2014-12-01

277

High-performance mass storage system for workstations  

NASA Technical Reports Server (NTRS)

Reduced Instruction Set Computer (RISC) workstations and Personnel Computers (PC) are very popular tools for office automation, command and control, scientific analysis, database management, and many other applications. However, when using Input/Output (I/O) intensive applications, the RISC workstations and PC's are often overburdened with the tasks of collecting, staging, storing, and distributing data. Also, by using standard high-performance peripherals and storage devices, the I/O function can still be a common bottleneck process. Therefore, the high-performance mass storage system, developed by Loral AeroSys' Independent Research and Development (IR&D) engineers, can offload a RISC workstation of I/O related functions and provide high-performance I/O functions and external interfaces. The high-performance mass storage system has the capabilities to ingest high-speed real-time data, perform signal or image processing, and stage, archive, and distribute the data. This mass storage system uses a hierarchical storage structure, thus reducing the total data storage cost, while maintaining high-I/O performance. The high-performance mass storage system is a network of low-cost parallel processors and storage devices. The nodes in the network have special I/O functions such as: SCSI controller, Ethernet controller, gateway controller, RS232 controller, IEEE488 controller, and digital/analog converter. The nodes are interconnected through high-speed direct memory access links to form a network. The topology of the network is easily reconfigurable to maximize system throughput for various applications. This high-performance mass storage system takes advantage of a 'busless' architecture for maximum expandability. The mass storage system consists of magnetic disks, a WORM optical disk jukebox, and an 8mm helical scan tape to form a hierarchical storage structure. Commonly used files are kept in the magnetic disk for fast retrieval. The optical disks are used as archive media, and the tapes are used as backup media. The storage system is managed by the IEEE mass storage reference model-based UniTree software package. UniTree software will keep track of all files in the system, will automatically migrate the lesser used files to archive media, and will stage the files when needed by the system. The user can access the files without knowledge of their physical location. The high-performance mass storage system developed by Loral AeroSys will significantly boost the system I/O performance and reduce the overall data storage cost. This storage system provides a highly flexible and cost-effective architecture for a variety of applications (e.g., realtime data acquisition with a signal and image processing requirement, long-term data archiving and distribution, and image analysis and enhancement).

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

1993-01-01

278

Two new systems with enhanced UV line flux ratios as indication of the evolution of cataclysmic variables  

NASA Astrophysics Data System (ADS)

We present ultraviolet spectra of 62 cataclysmic variables observed with Hubble Space Telescope Space Telescope Imaging Spectrograph & Faint Object Spectrograph (HST STIS FOS) to diagnose cataclysmic variables with enhanced NV/C IV line flux ratios. We concentrated on calculating the line flux ratios of the above mentioned sample. We found that a number of cataclysmic variables reveal enhanced NV/C IV line flux ratios in agreement with the previous studies ( de Martino and Gänsicke, 2009; Gänsicke et al., 2003). Also we found that two new systems (U SCO, V1974 CYG) reveal enhanced NV/C IV line flux ratios. Such anomalous line flux ratios confirmed that these CVs went through a phase of thermal timescale mass transfer (TTSMT) and now accrete CNO processed material from a companion stripped of its external layers ( Gänsicke et al., 2003; Gänsicke, 2004; de Martino and Gänsicke, 2009).

Sanad, M. R.

2011-01-01

279

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

280

LTI Systems with Generalized Frequency Variables: A Unified Framework for Homogeneous Multi-agent Dynamical Systems  

NASA Astrophysics Data System (ADS)

A linear system with a generalized frequency variable denoted by G(s) is a system which is given by replacing the variable ‘s’ in the original transfer function G0(s) with a rational function ‘?(s)’, i.e., G(s) is defined by G0(?(s)). A class of large-scale systems with decentralized information structures such as a homogeneous multi-agent systems, which has a common agent dynamics h(s)=1/?(s), can be represented by this form. In this paper, we investigate fundamental properties of such a class of systems in terms of controllability, observability, and stability. Specifically, we first derive necessary and sufficient conditions that guarantee controllability and observability of the system G(s) based on those of subsystems G0(s) and h(s). Then we show that the Nyquist type stability criterion can be reduced to a linear matrix inequality (LMI) feasibility problem. Finally, we apply the results to stability analysis of large-scale systems in three different fields and confirm the effectiveness of the approach as a general framework which can unify variety of results for homogeneous multi-agent dynamical systems.

Hara, Shinji; Hayakawa, Tomohisa; Sugata, Hikaru

281

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

NASA Astrophysics Data System (ADS)

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

Smith, Nathan; Tombleson, Ryan

2015-02-01

282

The imprint of Southern Ocean overturning on seasonal water mass variability in Drake Passage  

NASA Astrophysics Data System (ADS)

changes in water mass properties are discussed in thermohaline coordinates from a seasonal climatology and repeat hydrographic sections. The SR1b CTD transects along Drake Passage are used as a case study. The amount of water within temperature and salinity classes and changes therein are used to estimate dia-thermal and dia-haline transformations. These transformations are considered in combination with climatologies of surface buoyancy flux to determine the relative contributions of surface buoyancy fluxes and subsurface mixing to changes in the distribution of water in thermohaline coordinates. The framework developed provides unique insights into the thermohaline circulation of the water masses that are present within Drake Passage, including the erosion of Antarctic Winter Water (AAWW) during the summer months and the interaction between the Circumpolar Deep Waters (CDW) and Antarctic Intermediate Water (AAIW). The results presented are consistent with summertime wind-driven inflation of the CDW layer and deflation of the AAIW layer, and with new AAIW produced in the winter as a mixture of CDW, remnant AAWW, and surface waters. This analysis therefore highlights the role of surface buoyancy fluxes in the Southern Ocean overturning.

Evans, Dafydd Gwyn; Zika, Jan D.; Naveira Garabato, Alberto C.; Nurser, A. J. George

2014-11-01

283

Morphologic Variability of two Adjacent Mass-Transport Deposits: Twin Slides, Gela Basin (Sicily Channel).  

NASA Astrophysics Data System (ADS)

Integrating geophysical, sedimentological, structural and paleontological data, we reconstruct the age, size and internal geometry of two adjacent and recent mass-transport deposits (Twin Slides) exposed on the seafloor of Gela Basin (Sicily Channel). Twin Slides are coeval (late-Holocene), and were likely triggered by an earthquake. Twin Slides originated from the mobilization of Pleistocene slope units, are only 6 km apart from each other, have their headscarps in similar water depth (230 m), and have a comparable run out distance (ca. 10 km). Both slides suggest a multistage evolution, but differ in internal organization and morphological expression. The northern slide shows a deposit characterised by pressure ridges in the toe region suggesting a component of plastic deformation, while the southern slide is characterised by large blocks and a reduced thickness of displaced masses. We ascribe the difference in deformation style and resulting morphology to the stratigraphic architecture of the Pleistocene progradational units involved in failure. In the case of the blocky southern slide the units affected by failure are slightly older (Eemian or pre-Emian) and more consolidated; furthermore, in the area where the headscarp is located these units appear affected by shallow faulting likely resulting in the definition of large blocks. The northern slide, instead, affects progradational units of the Last Glacial Maximum in an area where these units are more than 100 m thick and, possibly, underconsolidated.

Minisini, D.; Trincardi, F.; Asioli, A.; Canu, M.; Foglini, F.

2006-12-01

284

Probing the geometric nature of particles mass in graphene systems  

E-print Network

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

Donatello Dolce; Andrea Perali

2014-03-13

285

Mass independent kinetic energy reducing inlet system for vacuum environment  

DOEpatents

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

Reilly, Peter T.A.

2013-12-03

286

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.

2014-05-13

287

Mass Polarization Effect in He-like Systems  

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

288

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

289

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

290

Decadal variability in coupled sea-ice-thermohaline circulation systems  

SciTech Connect

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

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

1997-12-01

291

Scalability and Performance Improvements in the Fermilab Mass Storage System  

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

292

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

293

Unsteady free convection on a vertical cylinder with variable heat and mass flux  

NASA Astrophysics Data System (ADS)

The unsteady natural convection boundary layer flow over a semi-infinite vertical cylinder is considered with combined buoyancy force effects, for the situation in which the surface temperature T'w(x) and C'w(x) are subjected to the power-law surface heat and mass flux as K(T'/r) = -axn and D(C'/r) = -bxm. The governing equations are solved by an implicit finite difference scheme of Crank-Nicolson method. Numerical results are obtained for different values of Prandtl number, Schmidt number `n' and `m'. The velocity, temperature and concentration profiles, local and average skin-friction, Nusselt and Sherwood numbers are shown graphically. The local Nusselt and Sherwood number of the present study are compared with the available result and a good agreement is found to exist.

Ganesan, P.; Rani, H. P.

294

Tidally-Forced Flow Variability Within Mid-Ocean Ridge Hydrothermal Systems: Models and Measurement Techniques  

E-print Network

black smoker hydrothermal vents. The first technique I develop is based on passive acoustic measurementsTidally-Forced Flow Variability Within Mid-Ocean Ridge Hydrothermal Systems: Models and Measurement of Washington Abstract Tidally-Forced Flow Variability Within Mid-Ocean Ridge Hydrothermal Systems: Models

Crone, Timothy J.

295

Variable time step, implicit integration for extended-term power system dynamic simulation  

Microsoft Academic Search

This paper describes the development of a variable time step algorithm for the numerical simulation of power system phenomena spanning time periods from several seconds to several hours. The algorithm automatically reduces the time step of integration to capture fast transients and increases it when the system variables are varying slowly. The solution algorithm is based on a numerically stable,

J. J. Sanchez-Gasca; R. D'Aquila; W. W. Price; J. J. Paserba

1995-01-01

296

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

Microsoft Academic Search

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

Yiwang Wang; Shuo Wu

2011-01-01

297

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

298

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

299

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

E-print Network

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

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

2002-01-01

300

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

E-print Network

ICEBO2006, Shenzhen, China Co ntrol Systems for Energy Efficiency and Comfort, Vol. V-4-2 Energy-Saving Design for Pressure Difference Control in Variable Flow Air Conditioning Systems Yanhua Chen Zaipeng...

Chen, Y.; Zhang, Z.

2006-01-01

301

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

PubMed Central

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

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

2014-01-01

302

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

PubMed

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

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

2014-01-01

303

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...

304

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...

305

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

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

306

The automation of an inlet mass flow control system  

NASA Technical Reports Server (NTRS)

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

Supplee, Frank; Tcheng, Ping; Weisenborn, Michael

1989-01-01

307

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.

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

1984-01-01

308

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

309

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

310

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

NASA Technical Reports Server (NTRS)

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

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

2000-01-01

311

The HD 192263 system: planetary orbital period and stellar variability disentangled  

E-print Network

As part of the Transit Ephemeris Refinement and Monitoring Survey (TERMS), 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 \\pm 0.0022 days. We use 10 years of Automated Photoelectric Telescope (APT) 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 a...

Dragomir, Diana; 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

2012-01-01

312

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

313

Mass-Flow-Meter Leak-Testing System  

NASA Technical Reports Server (NTRS)

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

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

1996-01-01

314

A mass storage system for supercomputers based on Unix  

NASA Technical Reports Server (NTRS)

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

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

1988-01-01

315

Oscillations and variability in the p53 system  

Microsoft Academic Search

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

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

2006-01-01

316

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

NASA Astrophysics Data System (ADS)

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

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

2010-04-01

317

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

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

318

The NEEDS Data Base Management and Archival Mass Memory System  

NASA Technical Reports Server (NTRS)

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

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

1980-01-01

319

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

320

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

321

An extrasolar planetary system with three Neptune-mass planets  

E-print Network

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.

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

2007-03-01

322

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

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

323

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

NASA Technical Reports Server (NTRS)

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

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

1988-01-01

324

A low-power dynamic variable-gain amplifier for ultrasonic imaging systems  

Microsoft Academic Search

A monolithic silicon integrated-circuit variable-gain amplifier was fabricated, which has no external parts, a minimum of noise, precisely controlled dynamically variable gain, low power consumption, and wide bandwidth. The amplifier is based on ion-implanted junction field effect transistors (JFETs) and is to be applied in a unique high-resolution real-time three dimensional ultrasonic imaging system (ULISYS) for medical diagnosis. Variable-gain amplifier

J. C. Long

1978-01-01

325

Cataclysmic Variables  

E-print Network

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

Robert Connon Smith

2007-01-23

326

Study of Neural Network PID Control in Variable-frequency Air-conditioning System  

Microsoft Academic Search

This paper aims at the control of variable-frequency air-conditioning system that has characteristic as large inertia and pure lag. The neural network PID control in the variable-frequency air-conditioning system is introduced and simulated. In the learning algorithm of neural network PID controller, the output of system is needed to tune the weights of neural network while it is difficult to

Jiangjiang Wang; Chunfa Zhang; Youyin Jing; Dawei An

2007-01-01

327

Variable frequency speed-regulation system of elevator using PLC technology  

Microsoft Academic Search

du.cn Abstract-In this paper, the system of variable frequency speed-regulation based on PLC was proposed. Firstly, the overall structure of control system was determined. Inverter and programmable logic controller were chosen to complete variable frequency speed-regulation . Secondly, parameters of inverter were set by develop system hardware. PLC drive selection and 110 points distribution were completed; rotary encoder was connected

Jing Jiang; Xuesong Zhang

2011-01-01

328

A mathematical model of variable displacement wobble plate compressor for automotive air conditioning system  

Microsoft Academic Search

Based on the force balance equations, mass and energy conservation equations, a mathematical model of control valve used in the variable displacement wobble plate compressor (VDC) is developed firstly. The dynamic model of the moving components is developed then by analyzing the forces and force moments acting on the piston, piston rod, wobble plate, rotating journal and shaft sleeve. The

Changqing Tian; Chunpeng Dou; Xinjiang Yang; Xianting Li

2004-01-01

329

Design of a ram accelerator mass launch system  

NASA Technical Reports Server (NTRS)

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

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

1988-01-01

330

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

331

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

PubMed

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

Sturm, Sebastian; Predel, Reinhard

2015-02-01

332

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

E-print Network

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

Paris-Sud XI, Université de

333

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

334

Instability of automotive air conditioning system with a variable displacement compressor. Part 1. Experimental investigation  

Microsoft Academic Search

A test system is built first in order to investigate the instability of the automotive air conditioning (AAC) system with a variable displacement compressor (VDC), and hunting phenomena caused by the large external disturbance in the AAC system with a VDC and a thermal expansion valve, and in the AAC system with a VDC and a fixed-area throttling device are

Changqing Tian; Chunpeng Dou; Xinjiang Yang; Xianting Li

2005-01-01

335

An inexpensive variable-frequency microwave system for hyperthermia.  

PubMed

A microwave hyperthermia system is described which uses surplus communications equipment. The most costly components of the microwave system, the signal generator and amplifier, were obtained through the Federal Surplus Supply System. The cost of the entire system, including 2450 MHz applicator and temperature monitoring system, is under $1200. Extensive testing has demonstrated the capability of heating several cm3 mouse tumors to a temperature of 42.5 degrees C. Depth of heating can be varied by adjusting the frequency of the oscillator or by adjusting the output attenuator. PMID:7464716

Cunningham, D E; Frey, R A; Velkley, D E

1980-01-01

336

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

NASA Technical Reports Server (NTRS)

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

Knox, J.

1986-01-01

337

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

338

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

PubMed

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

Choi, Jae Young; Ro, Yong Man

2012-11-01

339

Analysis of the electrical characteristics of a Westinghouse variable speed generating system for wind turbine applications  

Microsoft Academic Search

Variable speed electric generating technology can enhance the general use of wind energy in electric utility applications. This enhancement results from two characteristic properties of variable speed wind turbine generators: an improvement in drive train damping characteristics, which results in reduced structural loading on the entire wind turbine system, and an improvement in the overall efficiency by using a more

J. I. Herrera; T. W. Reddoch

1988-01-01

340

Mixed Variable Optimization of the Number and Composition of Heat Intercepts in a Thermal Insulation System  

Microsoft Academic Search

In the literature, thermal insulation systems with a fixed number of heat intercepts have been optimized with respect to intercept locations and temperatures. The number of intercepts and the types of insulators that surround them were chosen by parametric studies. This was because the optimization methods used could not treat such categorical variables. Discrete optimization variables are categorical if the

Michael Kokkolaras; Charles Audet; J. E. Dennis

2001-01-01

341

Harmonic propagation of variability in surface energy balance within a coupled soilvegetationatmosphere system  

E-print Network

Harmonic propagation of variability in surface energy balance within a coupled propagation of the harmonics in order to differentiate between the response of the system to forcing, P., J. Polcher, and D. Entekhabi (2011), Harmonic propagation of variability in surface energy

Gentine, Pierre

342

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

ERIC Educational Resources Information Center

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

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

2013-01-01

343

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

E-print Network

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

Paris-Sud XI, Université de

344

THE DETECTION OF ABUNDANCE ANOMALIES IN THE INFRARED SPECTRA OF CATACLYSMIC VARIABLES: SHORTER PERIOD SYSTEMS  

E-print Network

-band spectra for 12 cataclysmic variables (CVs) with orbital periods under 6 hr. We confidently detect the secondary stars in nine of these systems and may have detected them in the other three. Nine of the 12 CVs and evolution of CVs needs substantial revision. Key words: binaries: close -- novae, cataclysmic variables

Harrison, Thomas

345

Does the variable speed limit system on I-94 reduce crashes?  

E-print Network

and preferences for"large backyards"and"lots of off-street parking"owned a greater number of autos, whereas thoseDoes the variable speed limit system on I-94 reduce crashes? Variable speed continued on page 7 LRT crashes by recommending lower speed limits to drivers during periods of high traffic. The new technology

Levinson, David M.

346

Electro-hydraulic control system for a dual-pass continuously variable transmission  

SciTech Connect

This patent describes a control system for controlling the hydraulic pressure in a dual-pass continuously variable transmission system having a plurality of drive paths from a power input to a power output, and a continuously variable component including first and second variable pulleys disposed respectively on first and second intermediate shafts, the transmission system having first and second clutches engagable to effect transition from a first drive path in which the first variable pulley is the driver pulley to a second drive path in which the second variable pulley is the driver pulley, the transmission system being releasable to effect a transition from the second drive path to the first drive path. It comprises means to provide a primary hydraulic pressure to each of the first and second variable pulleys; means for providing a secondary hydraulic pressure to each of the first and second variable pulleys; means for electrically regulating the primary and secondary pressures responsive to engine conditions; and means for directing the primary and secondary hydraulic pressures to the first and second variable pulleys in response to change of drive path.

Algrain, M.C.; Anderson, S.R.; Smirl, R.L.

1991-07-16

347

The Mass Flux of Micrometeoroids Into the Saturnian System  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

348

A high pressure modulated molecular beam mass spectrometric sampling system  

NASA Technical Reports Server (NTRS)

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

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

1977-01-01

349

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

NASA Technical Reports Server (NTRS)

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

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

1988-01-01

350

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

351

Infall variability in the Classical T Tauri system VZ Chamaeleonis  

E-print Network

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

Smith, K W; Bonnell, I A; Emerson, J P

2001-01-01

352

Structure of variability of Alboran Sea frontal system  

SciTech Connect

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

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

1982-01-20

353

Variable structure control of a capsule robot system  

Microsoft Academic Search

Capsule robots have attracted great attention from researchers due to their potential applications in medicine. In this paper, the capsule robot system is studied from the control point of view, i.e. an underactuated system which has two degrees of freedom but only one control actuator. An exponentially stable robust nonlinear control scheme based on Lyapunov stability theory is studied on

Yang Liu; Hongnian Yu

2009-01-01

354

Managing Variability in the IO Performance of Petascale Storage Systems  

Microsoft Academic Search

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 largescale 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

Jay F. Lofstead; Fang Zheng; Qing Liu; Scott Klasky; Ron A. Oldfield; Todd Kordenbrock; Karsten Schwan; Matthew Wolf

2010-01-01

355

Impact of the Variable Refrigerant Volume Air Conditioning System on Building Energy Efficiency  

E-print Network

The application of the variable refrigerant volume multi-zone air conditioning systems has met with mixed results since the publication of the Design Standard for Energy Efficiency of Public Buildings. This paper analyzes the characteristics...

Zhu, H.

2006-01-01

356

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

357

Mass, Energy, Space And Time Systemic Theory---MEST  

NASA Astrophysics Data System (ADS)

Things have their physical system of the mass, energy, space and time of themselves-MEST. The matter have the physical systemic moel like that the mass-energy is center and the space-time is around. The time is from the frequency of wave, the space is from the amplitude of wave. What is the physical effection of the wave. The gravity and inertial force is from the wave. Not only the planets have the mass and the kinetic energy, but also it have the wave and the wave energy. According to the equivalence principle of the general relativity, there is the equation: ma=mg and mv^2 /2= ?mc^2. The energy equation of the planets: E=mv^2=mgr (v is velocity) be bring put forward. In quantum mechanics, according to the quantum light theory and the de Broglie's theory , there are the equation of the wave: E=h?, p=h/? (h is Planck constant, p is momentum, ? is the wavelengh), and there is the equation of the wave: E=mc^2. So the energy equation of the planets: E=mv^2 = mv^2 /2 + ?mc^2 (mv^2 /2= ?mc^2 ) be bring put forward. The equation: ?mc^2 show that the planets have the wave of itself, and the wave give the planets the energy. So it do not fall from the heaven. When the matter go into the heaven, it need get the wave energy (like the potential energy). So we can make a new light-flight with the light-driving force.

Cao, Dayong

2010-03-01

358

Design of a Ram Accelerator mass launch system  

NASA Technical Reports Server (NTRS)

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

1988-01-01

359

Computer-Aided Diagnostic System For Mass Survey Chest Images  

NASA Astrophysics Data System (ADS)

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

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

1988-06-01

360

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

361

An LED-based photovoltaic measurement system with variable spectrum and flash speed  

Microsoft Academic Search

Outdoor environmental variability generates the need for indoor systems for PV module characterisation. To combine the advantages of the most commonly used simulators (steady-state and pulsed) and eliminate their disadvantages, an LED-based solar simulator prototype has been developed. The system can produce light at variable flash speeds and pulse shapes or can operate as a continuous light source for long-term

M. Bliss; T. R. Betts; R. Gottschalg

2009-01-01

362

Systems for 42 V mass-market automobiles  

NASA Astrophysics Data System (ADS)

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

Keim, Thomas A.

363

PERSISTENCE AND PERMANENCE OF MASS-ACTION AND POWER-LAW DYNAMICAL SYSTEMS  

E-print Network

PERSISTENCE AND PERMANENCE OF MASS-ACTION AND POWER-LAW DYNAMICAL SYSTEMS GHEORGHE CRACIUN, FEDOR apply to power-law systems and other nonlinear dynamical systems. In addition, ideas behind and permanence for mass-action systems, and the more general power-law systems. A dynamical system on Rn >0

Craciun, Gheorghe

364

Transient Finite Element Computations on a Variable Transputer System  

NASA Technical Reports Server (NTRS)

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

Smolinski, Patrick J.; Lapczyk, Ireneusz

1993-01-01

365

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

SciTech Connect

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

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

2012-07-01

366

Orbit Approach to Separation of Variables in (3)-Related Integrable Systems  

NASA Astrophysics Data System (ADS)

Using the orbit method we reveal geometric and algebraic meaning of separation of variables for integrable systems on coadjoint orbits of an (3) loop algebra. We consider two types of generic orbits, embedded into a common manifold endowed with two nonsingular Lie-Poisson brackets. We prove that separation of variables on orbits of both types is realized by the same variables of separation. We also construct integrable systems on the orbits: a coupled 3-component nonlinear Schrödinger equation and an isotropic SU(3) Landau-Lifshitz equation.

Bernatska, Julia; Holod, Petro

2015-01-01

367

Orbit Approach to Separation of Variables in sl(3)-Related Integrable Systems  

NASA Astrophysics Data System (ADS)

Using the orbit method we reveal geometric and algebraic meaning of separation of variables for integrable systems on coadjoint orbits of an sl(3) loop algebra. We consider two types of generic orbits, embedded into a common manifold endowed with two nonsingular Lie-Poisson brackets. We prove that separation of variables on orbits of both types is realized by the same variables of separation. We also construct integrable systems on the orbits: a coupled 3-component nonlinear Schrödinger equation and an isotropic SU(3) Landau-Lifshitz equation.

Bernatska, Julia; Holod, Petro

2014-10-01

368

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

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

369

Thermodynamic analysis of variable speed refrigeration system using artificial neural networks  

Microsoft Academic Search

This study presents thermodynamic performance modeling of an experimental refrigeration system driven by variable speed compressor using artificial neural networks (ANNs) with small data sets. Controlling the rotational speed of compressor with a frequency inverter is one of the best methods to vary the capacity of refrigeration system. For this aim, an experimental refrigeration system was designed with a frequency

Önder Kizilkan

2011-01-01

370

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

371

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

Microsoft Academic Search

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

Xu Jinqiang; Feng Zi-ping

2009-01-01

372

Design of variable frequency endoscope ultrasonic digital imaging system  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

373

A Variable Ultraluminous Supersoft X-Ray Source in ``The Antennae'': Stellar-Mass Black Hole or White Dwarf?  

NASA Astrophysics Data System (ADS)

The Chandra monitoring observations of ``The Antennae'' (NGC 4038/4039) have led to the discovery of a variable, luminous, supersoft source (SSS). This source is detected only at energies below 2 keV and, in 2002 May, reached count rates comparable to those of the nine ultraluminous X-ray sources (ULXs) detected in these galaxies. Spectral fits of the SSS data give acceptable results only for a ~90-100 eV blackbody spectrum with an intrinsic absorption column of NH~(2-3)×1021 cm-2. For a distance of 19 Mpc, the best-fit observed luminosity increases from 1.7×1038 ergs s-1 in 1999 December to 8.0×1038 ergs s-1 in 2002 May. The intrinsic, absorption-corrected, best-fit luminosity reaches 1.4×1040 ergs s-1 in 2002 May. The assumption of unbeamed emission would suggest a black hole of >~100 Msolar. However, if the emission is blackbody at all times, as suggested by the steep soft spectrum, the radiating area would have to vary by a factor of ~103, inconsistent with gravitational energy release from within a few Schwarzschild radii of a black hole. Viable explanations for the observed properties of the SSS are provided by anisotropic emission from either an accreting nuclear-burning white dwarf or an accreting stellar-mass black hole.

Fabbiano, G.; King, A. R.; Zezas, A.; Ponman, T. J.; Rots, A.; Schweizer, François

2003-07-01

374

2D and 3D Mass Transfer Simulations in ? Lyrae System  

NASA Astrophysics Data System (ADS)

2D and 3D mass transfer simulations of the mass transfer in ? Lyrae binary system. We have received that from a point L3 40 per cent of mass transfer from L1-point is lost.The structure of a gas envelope, around system is calculated.3-D mass transfer simulations has shown presence the spiral shock in the disk around primary star's and a jet-like structures (a mass flow in vertical direction) over a stream.

Nazarenko, V. V.; Glazunova, L. V.; Karetnikov, V. G.

2001-12-01

375

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

376

SEASONAL VARIABILITY IN MEANDERS OF THE CALIFORNIA CURRENT SYSTEM OFF  

Microsoft Academic Search

Satellite infrared images taken over the past few years reveal seasonal variations in the meanders of the California Current System (CCS) off Vancouver Island. The CCS exhibits meanders with wavelength between 120 and 150 km in both winter and spring, when the upper ocean current all flows northwestward or southeastward, respectively. In summer, the CCS includes the California Undercurrent, which

M. Ikeda; W. J. Emery; L. A. Mysak

1984-01-01

377

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

NASA Technical Reports Server (NTRS)

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

Gmirya, Yuriy (Inventor)

2003-01-01

378

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...

379

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

NASA Technical Reports Server (NTRS)

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

Bailey, G. A.

1980-01-01

380

System albedo as sensed by satellites - Its definition and variability  

NASA Technical Reports Server (NTRS)

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

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

1982-01-01

381

Internal combustion engine air intake system with variable effective length  

SciTech Connect

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

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

1988-04-19

382

Automatically Finding the Control Variables for Complex System Behavior  

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

383

Super Efimov effect for mass-imbalanced systems  

NASA Astrophysics Data System (ADS)

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

Moroz, Sergej; Nishida, Yusuke

2014-12-01

384

Super Efimov effect for mass-imbalanced systems  

E-print Network

We study two species of particles in two dimensions interacting by isotropic short-range potentials with the interspecies potential fine-tuned to a p-wave resonance. Their universal low-energy physics can be extracted by analyzing a properly constructed low-energy effective field theory with the renormalization group method. Consequently, a three-body system consisting of two particles of one species and one of the other is shown to exhibit the super Efimov effect, the emergence of an infinite tower of three-body bound states with orbital angular momentum $l=\\pm1$ whose binding energies obey a doubly exponential scaling, when the two particles are heavier than the other by a mass ratio greater than 4.03404 for identical bosons and 2.41421 for identical fermions. With increasing the mass ratio, the super Efimov spectrum becomes denser which would make its experimental observation easier. We also point out that the Born-Oppenheimer approximation is incapable of reproducing the super Efimov effect, the universal low-energy asymptotic scaling of the spectrum.

Sergej Moroz; Yusuke Nishida

2014-07-29

385

Zero and root loci of disturbed spring–mass systems  

PubMed Central

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

Lecomte, Christophe

2014-01-01

386

Lumped mass formulations for modeling flexible body systems  

NASA Technical Reports Server (NTRS)

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

Rampalli, Rajiv

1989-01-01

387

Variable Conduction System Disorders in Takotsubo Cardiomyopathy: A Case Series  

PubMed Central

Takotsubo cardiomyopathy is an acute cardiac condition characterized by transient systolic dysfunction of the left ventricular apex and mid-ventricle. Documented EKG presentations for Takotsubo cardiomyopathy include ST-segment elevation or T-wave inversion. These EKG presentations are included in the diagnostic requirements for Takotsubo cardiomyopathy. This paper presents two cases of atypical EKG presentations, both conduction system disorders, and their possible mechanisms. Changes to the diagnostic criteria for Takotsubo cardiomyopathy should be considered to include these variant EKG presentations. PMID:24843838

Hoo, Aaron C; Azuma, Steven S

2014-01-01

388

Time-Variable Phenomena in the Jovian System  

NASA Technical Reports Server (NTRS)

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

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

1989-01-01

389

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

390

The bottom quark mass from the system at NNNLO  

NASA Astrophysics Data System (ADS)

We obtain an improved determination of the normalization constant of the first infrared renormalon of the pole mass (and the singlet static potential). For N f = 3 it reads N m = 0 .563(26). Charm quark effects in the bottom quark mass determination are carefully investigated. Finally, we determine the bottom quark mass using the NNNLO perturbative expression for the mass. We work in the renormalon subtracted scheme, which allows us to control the divergence of the perturbation series due to pole mass renormalon. Our result for the mass reads MeV.

Ayala, César; Cveti?, Gorazd; Pineda, Antonio

2014-09-01

391

Mass bounds on a dileptonic system from cosmology  

NASA Astrophysics Data System (ADS)

The interaction of two leptons of mass greater than a few GeV which couple only to the Z(0) neutral vector boson is investigated analytically, considering the case of the departure of the dilepton from chemical equilibrium during the very early hot Big Bang universe. The present mass density of the bilepton is determined, and constraints on the mass are obtained: the dilepton mass must be greater than about 15 GeV, and the mass difference must be less than 10 percent of the dilepton mass.

Salati, P.

392

Clutch control system with variable clutch connection position  

SciTech Connect

A clutch control system is described for controlling a clutch to transmit and cut off rotation from an automobile engine to wheels of the automobile, the clutch control system comprising: a gear transmission, having lubricating oil, for changing the speed of the transmitted rotation from the automobile engine; a clutch, coupled between the automobile engine and the gear transmission, for transmitting rotation from the automobile engine to the gear transmission; a clutch actuator, coupled to the clutch, for operating the clutch between a connected position and a disconnected position with respect to the automobile engine; means for learning and storing a learned value corresponding to a position at which to start connecting the clutch; means, coupled to the gear transmission, for detecting the temperature of the lubricating oil of the gear transmission; means of storing a corrective clutch control value corresponding to the detected temperature of the lubricating oil; and means, coupled to the learning means and the storing means, for correcting the learned value by the corrective clutch control value derived from the detected temperature of the lubricating oil to provide a new learned value.

Yoshimura, H.; Hattori, T.

1987-07-07

393

A very high performance stabilization system for large mass bolometerexperiments  

NASA Astrophysics Data System (ADS)

CUORE is a large mass bolometric experiment, composed of 988 crystals, under construction in Hall A of the Gran Sasso Underground Laboratories (LNGS). Its main aim is the study of neutrinoless double beta decay of 130Te. Each bolometer is a 760 g crystal of Tellurium dioxide on which a Nuclear Transmutation Doped Ge thermistor, Ge NTD, is glued with proper thermal contact. The stability of the system is mandatory over many years of data taking. To accomplish this requirement a heating resistor is glued on each detector across which a voltage pulse can be injected at will, to develop a known calibrated heating power. We present the design solution for a pulse generator system to be used for the injection of such a small and short voltage pulse across the heaters. This system is composed by different custom PCB boards each of them having multi-channel independent outputs completely remotely programmable from the acquisition system, in pulse width and amplitude, through an on-board ARM7 microcontroller. Pulse amplitudes must be selectable, in order to handle each detector on its full dynamic range. The resolution of the output voltage is 12 bits over 10 V range. An additional 4 steps programmable voltage attenuator is added at every output. The width of any pulse can range from 100 ?s to 25.5 ms. The main features of the final system are: stability and precision in pulses generation (at the level of less than a ppm/°C), low cost (thanks to the use of commercial components) and compact implementation.

Arnaboldi, C.; Giachero, A.; Gotti, C.; Pessina, G.

2011-10-01

394

Analysis of the electrical characteristics of a Westinghouse variable speed generating system for wind turbine applications  

NASA Astrophysics Data System (ADS)

Variable speed electric generating technology can enhance the general use of wind energy in electric utility applications. This enhancement results from two characteristic properties of variable speed wind turbine generators: an improvement in drive train damping characteristics, which results in reduced structural loading on the entire wind turbine system, and an improvement in the overall efficiency by using a more sophisticated electrical generator. Electronic converter systems are the focus of this investigation, particularly the properties of a Westinghouse variable-speed, constant-frequency system with wound-rotor induction generator and a cycloconverter. Experience with solid-state converter systems in large wind turbines is extremely limited. This report presents measurements of electrical performances of the Westinghouse system and is limited to the terminal characteristics of the system. Variable speed generating systems working effectively in utility applications will require a satisfactory interface between the turbine-generator pair and the utility network. The electrical testing described herein focuses largely on the interface characteristics of the generating system. A MOD-0 wind turbine was connected to a very strong system; thus, the voltage distortion was low and the total harmonic distortion in the utility voltage was less than 3 percent (within the 5 percent limit required by most utilities). The largest voltage component of a frequency below 60 Hz was 40 dB down from the 60-Hz component.

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

1988-02-01

395

System for throttling and compensation for variable feedstock properties  

DOEpatents

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

Meyer, John W. (Palo Alto, CA)

1981-01-01

396

Design of power system stabilizer through state variable feedback  

SciTech Connect

When the transmission line is very long or the generator is operated at a power factor nearly equal to 1.0, the machine regulated by an automatic voltage regulator (AVR) cannot be operated stably due to poor dynamic stability. To overcome this difficulty, the so called power system stabilizer (PSS) is very useful, in that output power or rotor speed of the generator is used as a feedback signal. The primary obective of the PSS is to damp the swing of the generator as quickly as possible. A method is proposed for designing PSS which yields a given eigenvalue. In the second method, the use of a Heffron-Phillips model is discussed. Next, a detailed procedure for the proposed design method is presented. A generalized method of a PSS design based on Park's equation and matrix operation is proposed.

Abe, S.; Takeda, S.

1980-05-01

397

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

NASA Astrophysics Data System (ADS)

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

France, Kevin

2014-10-01

398

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

NASA Technical Reports Server (NTRS)

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

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

1980-01-01

399

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

Microsoft Academic Search

SummaryAim: 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

Zehra H. Adibelli; Ruken Ergenc; Ozgur Oztekin; Suheyla Ecevit; Gokhan Unal

2010-01-01

400

Phase topology of one system with separated variables and singularities of the symplectic structure  

NASA Astrophysics Data System (ADS)

We consider an example of a system with two degrees of freedom admitting separation of variables but having a subset of codimension 1 on which the 2-form defining the symplectic structure degenerates. We show how to use separation of variables to calculate the topological invariants of non-degenerate singularities and singularities appearing due to the symplectic structure degeneration. New types of non-orientable 3-atoms are found.

Kharlamov, M. P.

2015-01-01

401

Wind speed sensorless maximum power point tracking control of variable speed wind energy conversion systems  

Microsoft Academic Search

A maximum power point tracking (MPPT) controller for variable speed wind energy conversion system (WECS) is proposed. The proposed method, without requiring the knowledge of wind speed, air density or turbine parameters, generates at its output the optimum speed command for speed control loop of rotor flux oriented vector controlled machine side converter control system using only the instantaneous active

J. S. Thongam; P. Bouchard; H. Ezzaidi; M. Ouhrouche

2009-01-01

402

Effect of room modelling and sensor position on performance assessment of variable air volume control systems  

Microsoft Academic Search

Variable air volume (VAV) systems are commonly used for air conditioning in buildings. The testing of different control strategies and controllers for this application has been a main concern in several simulation studies. In these simulations much attention has been paid to the accuracy of the models of the VAV system while very simple models are often used at the

P Riederer; A L Dexter

2003-01-01

403

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

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

Technical Stability of Nonstationary Automatic-Control Systems with Variable Structure  

Microsoft Academic Search

Sufficient conditions of technical stability in measure are established for nonstationary automatic-control systems with variable structure and logic control laws dependent on the mismatch error and its derivatives of finite order for all admissible initial perturbations from a predefined measurable set of initial perturbations. The associated systems of differential equations contain time-dependent coefficients. The logic control laws are described by

Konstantin Savvich Matviichuk

2003-01-01

406

The model of the variable speed constant frequency closed-loop system operating in generating state  

Microsoft Academic Search

The variable speed constant frequency (USCF) electrical power system is a new type of aircraft power supply, which contains an alternating generator and a cycloconverter. This sums up the work of the cycloconverter and obtains four fundamental classes of circuit construction of the closed-loop system, which have twelve operating models. A mathematical model for each fundamental class of the circuit

Daohong Ding

1986-01-01

407

Modelling and Reconstruction of the North Atlantic Climate System Variability (MONALISA III)  

E-print Network

-ocean system shows low-frequency regime behavior (e.g., the Atlantic Multidecadal Oscillation; AMO; Dijkstra et12 P 1.1 Modelling and Reconstruction of the North Atlantic Climate System Variability (MONALISA to changes in external forcing functions in the North Atlantic during key periods of the past 1000 years

Richner, Heinz

408

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

409

A variable speed wind energy conversion scheme for connection to weak AC systems  

Microsoft Academic Search

A three level control system for a variable speed wind energy conversion scheme (VSWECS) supplying a weak AC power system is presented. The objective of the control strategy is to maximize energy capture and simultaneously to support the voltage of the bus where the VSWECS is connected. Using an insulated gate bipolar transistor (IGBT) inverter, both control of active and

A. S. Neris; N. A. Vovos; G. B. Giannakopoulos

1999-01-01

410

Instability of automotive air conditioning system with a variable displacement compressor. Part 2. Numerical simulation  

Microsoft Academic Search

In order to determine the conservative stable region (CSR) proposed in part 1 of this paper, a dynamic model of the automotive air conditioning system with a variable displacement compressor and a thermal expansion valve is developed. The sensitivity analysis is done to show how uncertainties in input parameters influence the predicted results of system performance. The dynamic simulation is

Changqing Tian; Chunpeng Dou; Xinjiang Yang; Xianting Li

2005-01-01

411

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...

412

Improving the effectiveness of solar pumping systems by using modular centrifugal pumps with variable rotational speed  

Microsoft Academic Search

The possibility of improving the performance of deep well solar pumping systems by using centrifugal pumps with variable rotational speed and modular number of working stages (i.e. Divided Shaft Pump, DSP) was investigated and compared with traditional systems equipped with pumps having a fixed number of stages (i.e Standard Centrifugal Pump, SCP). Starting from commercially available pumps with a given

Daniele Fiaschi; Roberto Graniglia; Giampaolo Manfrida

2005-01-01

413

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

414

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

415

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

416

The Effect of Mass Transit Systems on Price of Condominium in Bangkok  

E-print Network

The Effect of Mass Transit Systems on Price of Condominium in Bangkok Undergraduate Honor Thesis condominiums near the mass transit route significantly as consumers are willing to pay more for the convenience. A hedonic price model is used to analyze the effect of mass transit systems on the price of condominiums

Sadoulet, Elisabeth

417

Reducing experimental variability in variance-based sensitivity analysis of biochemical reaction systems  

NASA Astrophysics Data System (ADS)

Sensitivity analysis is a valuable task for assessing the effects of biological variability on cellular behavior. Available techniques require knowledge of nominal parameter values, which cannot be determined accurately due to experimental uncertainty typical to problems of systems biology. As a consequence, the practical use of existing sensitivity analysis techniques may be seriously hampered by the effects of unpredictable experimental variability. To address this problem, we propose here a probabilistic approach to sensitivity analysis of biochemical reaction systems that explicitly models experimental variability and effectively reduces the impact of this type of uncertainty on the results. The proposed approach employs a recently introduced variance-based method to sensitivity analysis of biochemical reaction systems [Zhang et al., J. Chem. Phys. 134, 094101 (2009)] and leads to a technique that can be effectively used to accommodate appreciable levels of experimental variability. We discuss three numerical techniques for evaluating the sensitivity indices associated with the new method, which include Monte Carlo estimation, derivative approximation, and dimensionality reduction based on orthonormal Hermite approximation. By employing a computational model of the epidermal growth factor receptor signaling pathway, we demonstrate that the proposed technique can greatly reduce the effect of experimental variability on variance-based sensitivity analysis results. We expect that, in cases of appreciable experimental variability, the new method can lead to substantial improvements over existing sensitivity analysis techniques.

Zhang, Hong-Xuan; Goutsias, John

2011-03-01

418

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

PubMed

Chondrichthyans (sharks, batoids, and chimaeras) have simple feeding mechanisms owing to their relatively few cranial skeletal elements. However, the indirect association of the jaws to the cranium (euhyostylic jaw suspension) has resulted in myriad cranial muscle rearrangements of both the hyoid and mandibular elements. We examined the cranial musculature of an abbreviated phylogenetic representation of batoid fishes, including skates, guitarfishes and with a particular focus on stingrays. We identified homologous muscle groups across these taxa and describe changes in gross morphology across developmental and functional muscle groups, with the goal of exploring how decoupling of the jaws from the skull has effected muscular arrangement. In particular, we focus on the cranial anatomy of durophagous and nondurophagous batoids, as the former display marked differences in morphology compared to the latter. Durophagous stingrays are characterized by hypertrophied jaw adductors, reliance on pennate versus fusiform muscle fiber architecture, tendinous rather than aponeurotic muscle insertions, and an overall reduction in mandibular kinesis. Nondurophagous stingrays have muscles that rely on aponeurotic insertions onto the skeletal structure, and display musculoskeletal specialization for jaw protrusion and independent lower jaw kinesis, relative to durophagous stingrays. We find that among extant chondrichthyans, considerable variation exists in the hyoid and mandibular muscles, slightly less so in hypaxial muscles, whereas branchial muscles are overwhelmingly conserved. As chondrichthyans occupy a position sister to all other living gnathostomes, our understanding of the structure and function of early vertebrate feeding systems rests heavily on understanding chondrichthyan cranial anatomy. Our findings highlight the incredible variation in muscular complexity across chondrichthyans in general and batoids in particular. PMID:24652648

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

2014-08-01

419

Automatic Handling Mechanisms For An Optical Disc Mass Memory System  

NASA Astrophysics Data System (ADS)

An optical disc mass memory system is being developed which will provide automatic access to any data in a store of 1013 bits within five seconds. This system contains a library of 128 optical discs with mechanisms for retrieving any disc, loading it onto a turntable, and recording or playing digital data at a rate of 50 Mb/s. The optical discs are housed in protective cartridges to facilitate handling by the operating personnel and automatic disc handling mechanisms. Cartridges are moved from the store to a load station by a belt-driven X-Y transport mechanism. The load station then mounts the discs onto a precision turntable, and they are spun up to speed while housed within their protective cartridges. A window in the cartridge wall provides access for the record and play laser beams to operate on the disc media. The disc handling mechanisms were designed to minimize mechanical shock and vibration while providing a rapid, smooth operation. A special centering hub design, for the turntable minimizes disc eccentricities during multiple load/unload cycles and allows easy inter-changeability among machines. This paper will describe the cartridge, turntable, and disc handling mechanisms designs. Test results from an engineering model implementing these designs will also be presented.

Ammon, G. J.; Siryj, B. W.

1983-09-01

420

Identification of a wide, low-mass multiple system containing the brown dwarf 2MASS J0850359+105716  

E-print Network

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 ...

Faherty, Jacqueline K.

421

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

SciTech Connect

A control system for a continuously variable transmission for transmitting the power of an internal combustion engine to driving wheels through a clutch, having a drive pulley having a hydraulically shiftable disc and a first hydraulic cylinder for shifting the disc, a driven pulley having a hydraulically shiftable disc and a second hydraulic cylinder for operating the disc, a belt engaged with both pulleys, a line pressure control valve having ports and a spool, a transmission ratio control valve having ports and a spool, a first hydraulic circuit having a pump for supplying oil to the first cylinder through the line pressure control valve and transmission ratio control valve, the system comprising: a second hydraulic circuit for supplying oil to the line pressure control valve so as to shift the spool; control valve means provided in the second hydraulic circuit for controlling amount of oil supplied to the line pressure control valve; first means for detecting a large transmission ratio state after disengagement of the clutch and for producing a signal; second means responsive to the signal from the first means for producing a line pressure reducing signal; third means responsive to the line pressure reducing signal for operating the control valve means, so that the spool of the line pressure control valve is shifted to reduce the line pressure.

Miyawaki, M.

1987-06-23

422

Deep, Low Mass Ratio Overcontact Binary Systems. III. CU Tauri and TV Muscae  

NASA Astrophysics Data System (ADS)

New CCD photometric light curves in the B and V bands of the neglected W UMa-type eclipsing variable star CU Tauri are presented. The O'Connell effect in the V light curve obtained in 2001 by Yang and Liu was about ?V=+0.015, but it vanished in our 2004 observations. The variations in the levels of both minima were seen. Our two epochs of light minimum and others compiled from the literature were used for the period study. It is shown that the types of some eclipse times were incorrect and the values of the period obtained by previous investigators were aliases that prevented formation of a plausible O-C curve. A new linear ephemeris was derived, and it is discovered that the orbital period of CU Tau shows a continuous decrease at a rate of dP/dt=-1.81×10-6 days yr-1. The present symmetric light curves were solved with the 2003 version of the Wilson-Devinney (W-D) code. Both our solutions and those derived by Yang and Liu reveal that CU Tau is a deep (f=50.1%+/-3.2%), low mass ratio (q=0.1770+/-0.0017) overcontact binary system. Meanwhile, the photoelectric light curves in the B, V, R, and I bands of TV Muscae published by Hilditch and coworkers were reanalyzed with the 2003 version of the W-D code. It is shown that the low mass ratio binary turns out to be a deep overcontact system with f=74.3%+/-11.3%. A period analysis with all collected times of light minimum revealed a combination of a long-term period decrease (dP/dt=-2.16×10-7 days yr-1) and a possible cyclic change with a period of 29.1 yr. The rapid long-term period decreases of both systems can be explained as a combination of the mass transfer from the more massive component to the less massive one and the angular momentum loss due to mass outflow from the L2 point. In that way, the overcontact degrees of the two systems will become deeper as their periods decrease, and finally they will evolve into a single rapid-rotation star. However, for CU Tau, the rate of the secular period decrease is very large when compared with the other systems of the same type. This suggests that the long-term period decrease may be part of a long-period periodic change, which we need more data to check.

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

2005-07-01

423

Diagnosing Natural Variability of North Atlantic Water Masses in HadCM3 KEITH HAINES AND CHRIS OLD  

E-print Network

into the mixed layer. 1. Introduction The Lagrangian conserved properties of ocean water masses within the main thermocline vary only on long time scales, and therefore a record of these water mass properties and volumes the Gulf Stream and North Atlantic Current. However, anomalies in the volume and properties of water masses

424

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

SciTech Connect

This patent describes a control system for a continuously variable transmission for transmitting the power of an internal combustion engine having a throttle valve to driving wheels of a motor vehicle through a clutch, the transmission having a drive pulley including a hydraulically shiftable disc and a first hydraulic cylinder for shifting the disc, a driven pulley including a hydraulically shiftable disc and a second hydraulic cylinder for operating the disc of the driven pulley, and a belt engaged with both pulleys, the control system having a line pressure control valve having ports and a shiftable spool, a transmission ratio control having ports and a shiftable spool, and a first hydraulic circuit having a pump for supplying oil regulated by the line pressure control valve to the first hydraulic cylinder via the transmission ratio control valve and to the second hydraulic cylinder. The improvement in the system consists of: a second hydraulic circuit for supplying control oil to the line pressure control so as to shift the spool of the line pressure control valve; control valve means provided in the second hydraulic circuit for controlling the amount of the control oil supplied to the line pressure control valve; sensor means for sensing operating conditions and for producing first signals; first means responsive to at least one of the first signals for producing an engine torque representing engine torque in acceleration state and state state respectively; second means responsive to at least one of the first signals when the throttle valve is closed during driving of the vehicle for producing an acceleration/deceleration signal representing engine braking conditions.

Miyawaki, M.

1988-09-20

425

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

SciTech Connect

This patent describes a control system for a continuously variable transmission for transmitting the power of an internal combustion engine, the transmission comprising a drive pulley having a hydraulically shiftable first disc and a first hydraulic cylinder for shifting the disc, a driven pulley having a hydraulically shiftable second disc and a second hydraulic cylinder for operating the second disc, and a belt engaged with both pulleys, the system comprising a line pressure control valve having a shiftable first spool, a transmission ratio control valve having a shiftable second spool, a first hydraulic circuit having a pump for supplying oil to the first cylinder through the line pressure control valve and transmission ratio control valve, the improvement in the control system which comprises: a second hydraulic circuit for supplying the oil from the pump to the line pressure control valve so as to shift the first spool of the line pressure control valve; a flow rate control valve provided in the second hydraulic circuit for regulating flow rate of oil passing therethrough from an inlet port thereof to an outlet port thereof to a constant value; a reducing valve provided in the second hydraulic circuit and having an inlet communicated with the outlet port of the flow rate control valve so as to produce a constant pressure of oil at an outlet from the reducing valve; control valve means provided in the second hydraulic circuit at a downstream position of the reducing valve communicating with the outlet of the reducing valve for controlling the amount of oil supplied to the first spool of the line pressure control valve so as to shift the first spool of the line pressure control valve to control line pressure in the first hydraulic circuit.

Satoh, K.

1989-06-27

426

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

427

Technical stability of stationary automatic control systems of variable structure with switched filters  

Microsoft Academic Search

Sufficient conditions for the technical stability in measure of a nonstationary control system with variable structure are\\u000a established. The controller of the system has feedback-switched filters functioning together with shaper and actuator. It\\u000a is assumed that the nonstationary parameters of the system vary within given ranges, at a finite rate, with appropriate control\\u000a laws, with adjustment against mismatch signal, its

K. S. Matviichuk

2006-01-01

428

Stability in sliding mode of nonstationary automatic-control systems of variable structure with switched filters  

Microsoft Academic Search

Stability conditions for a nonstationary automatic-control system of variable structure in sliding mode are established. The\\u000a controller of the system has feedback-switched filters functioning together with the shaper and actuator. The nonstationary\\u000a parameters of the system vary within given ranges, at a finite rate, under appropriate control laws, with adjustment for the\\u000a error signal, its derivatives of finite order, and

K. S. Matviichuk

2006-01-01

429

Control design variable linking for optimization of structural/control systems  

NASA Technical Reports Server (NTRS)

A method is presented to integrate the design space of structural/control system optimization problems in the case of linear state feedback control. Conventional structural sizing variables and elements of the feedback gain matrix are both treated as strictly independent design variables in optimization by extending design variable linking concepts to the control gains. Several approximation concepts including new control design variable linking schemes are used to formulate the integrated structural/control optimization problem as a sequence of explicit nonlinear mathematical programming problems. Examples which involve a variety of behavior constraints, including constraints on dynamic stability, damped frequencies, control effort, peak transient displacement, acceleration, and control force limits, are effectively solved by using the method presented.

Jin, Ik Min; Schmit, Lucien A.

1993-01-01

430

The Attributes of a Variable-Diameter Rotor System Applied to Civil Tiltrotor Aircraft  

NASA Technical Reports Server (NTRS)

The attributes of a variable diameter rotor concept applied to civil tiltrotor aircraft are investigated using the V/STOL aircraft sizing and performance computer program (VASCOMP). To begin, civil tiltrotor viability issues that motivate advanced rotor designs are discussed. Current work on the variable diameter rotor and a theoretical basis for the advantages of the rotor system are presented. The size and performance of variable diameter and conventional tiltrotor designs for the same baseline mission are then calculated using a modified NASA Ames version of VASCOMP. The aircraft are compared based on gross weight, fuel required, engine size, and autorotative performance for various hover disk loading values. Conclusions about the viability of the resulting designs are presented and a program for further variable diameter rotor research is recommended.

Brender, Scott; Mark, Hans; Aguilera, Frank

1996-01-01

431

A study of engine variable geometry systems for an advanced high subsonic long range commercial aircraft  

NASA Technical Reports Server (NTRS)

Several variable geometry high Mach inlet concepts, aimed at meeting a system noise objective of 15 EPNdB below FAR part 36, for a long range, Mach 0.9 advanced commercial transport are assessed and compared to a fixed geometry inlet with multiple splitters. The effects of a variable exhaust nozzle (mixed exhaust engine) on noise, inlet geometry requirements, and economics are also presented. The best variable geometry inlet configuration identified is a variable cowl design which relies on a high throat Mach number for additional inlet noise suppression only at takeoff, and depends entirely on inlet wall treatment for noise suppression at approach power. Relative economic penalties as a function of noise level are also presented.

Compagnon, M. A.

1973-01-01

432

The RenewElec Project: Variable Renewable Energy and the Power System  

SciTech Connect

Variable energy resources, such as wind power, now produce about 4% of U.S. electricity. They can play a significantly expanded role if the U.S. adopts a systems approach that considers affordability, security and reliability. Reaching a 20-30% renewable portfolio standard goal is possible, but not without changes in the management and regulation of the power system, including accurately assessing and preparing for the operational effects of renewable generation. The RenewElec project will help the nation make the transition to the use of significant amounts of electric generation from variable and intermittent sources of renewable power.

Apt, Jay

2014-02-14

433

On the migration-induced resonances in a system of two planets with masses in the Earth mass range  

E-print Network

We investigate orbital resonances expected to arise when a system of two planets, with masses in the range 1-4 Earth masses, undergoes convergent migration while embedded in a section of gaseous disc where the flow is laminar. We consider surface densities corresponding to 0.5-4 times that expected for a minimum mass solar nebula at 5.2 AU. Using hydrodynamic simulations we find that when the configuration is such that convergent migration occurs the planets can become locked in a first order commensurability for which the period ratio is (p+1)/p with p being an integer and migrate together maintaining it for many orbits. Relatively rapid convergent migration as tends to occur for disparate masses, results in commensurabilities with p larger than 2. However, in these cases the dynamics is found to have a stochastic character. When the convergent migration is slower, such as occurs in the equal mass case, lower p commensurabilities such as 3:2 are attained which show much greater stability. In one already known example of a system with nearly equal masses in the several Earth mass range (planets around pulsar PSR B1257+12) the two largest planets are intriguingly close to a 3:2 commensurability. A very similar behaviour is obtained when the systems are modeled using an N body code with simple prescriptions for the disc planet interaction. Using that, we found that an 8:7 resonance established in a hydrodynamic simulation run for 10-100 thousand orbits could be maintained for more than million orbits. Resonant capture leads to a rise in eccentricities that can be predicted using a simple analytic model constructed in this paper. We find that the system with the 8:7 commensurability is fully consistent with this prediction.

J. C. B. Papaloizou; E. Szuszkiewicz

2005-07-26

434

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

NASA Astrophysics Data System (ADS)

High density CTD and XBT sections were covered from 35° to 56°S along 45°E and 57°30'E to investigate the morphology of the main fronts in the southwest Indian Ocean, as a part of the Indian pilot expedition to the Southern Ocean on board ORV Sagar Kanya. Northern branch of the Subtropical Front (NSTF) was observed at ˜ 35°30'S along 45°E. Along 57°30'E, the signature of the Agulhas Return Front (ARF) + Subtropical Front (STF) was identified with a rapid decrease in surface temperature between 43°30' and 45°S and it is located with a southward shift compared to that at 45°E. The Subantarctic Front (SAF) was distinguished as two fronts as northern SAF (SAF1) and southern SAF (SAF2) along both the meridional sections. Polar Front1 (PF1) was identified between 49° and 50°S whereas Polar Front2 (PF2) was identified between 52° and 54°S along 45°E. This study reveals a southward shift of the oceanic fronts (ARF + STF) from west to east, with a maximum southward displacement of > 2° latitude at 57°30'E. A novel finding of this study is that along 45°E, SAF1 merged with ARF and SSTF and SAF2 ˜ 4° latitude southwards from the merged fronts whereas along 57°30'E, SAF1 was not identified as a merged front with ARF and STF as opposed to earlier studies [Belkin, I.M., Gordon, A.L., 1996. Southern Ocean fronts from the Greenwich Meridian to Tasmania. Journal of Geophysical Research 101, 3675-3696]. The thermocline region was absent south of PF. An enhancement in the mixed layer thickness from 42° to 52°S occurred in association with the strengthening of the wind forcing. Major water masses like Subtropical Surface Water, Subantarctic Surface Water, Mode Water, Antarctic Intermediate Water, Circumpolar Deep Water and Antarctic Bottom Water were identified along 45°E. Upper-ocean heat-content computation revealed a remarkable drop of 989 × 10 7 J m -2 at ˜ 42°S and 1405 × 10 7 J m -2 at ˜ 44°S along 45° and 57°30'E, respectively. We believe that this sudden drop in heat content affects the meridional heat transfer which is crucial to the regional climatic variability.

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

2006-11-01

435