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Sample records for air mass ratio

  1. Background NO/sub x/ mixing ratios in air masses over the North Atlantic ocean

    SciTech Connect

    Helas, G.; Warneck, P.

    1981-08-20

    A chemiluminescence analyzer was used to measure NO/sub x/ mixing ratios at the west coast of Ireland. Two measurement modes allowed the determination of NO and NO/sub x/ = NO+NO/sub 2/. In a third mode using a molybdenum converter, higher signals were observed than was in the second mode indicating that nitrogen compounds other than NO+NO/sub 2/ are registered. They are denoted 'excess NO/sub x/'. The average NO/sub 2/ mixing ratio for a week period was 101 +- 87 pptv. In pure marine air masses identified by means of trajectory calculations, the NO/sub 2/ mixing ratios were lower and exhibited in addition a diurnal variation with nighttime values of 37 +- 6 pptv and average values of 87 +- 47 pptv. Possible origins of the diurnal variation are discussed. For such conditions, the NO mixing ratio generally was unmeasurably small, certainly less than 10 pptv. The excess NO/sub x/ is also higher during the day compared with nighttime values of about 70 pptv. Further studies are required to identify the compounds involved.

  2. HIGH PRECISION ISOTOPE RATIO MASS SPECTROMETRY METHOD FOR MEASURING THE O2/N2 RATIO OF AIR

    EPA Science Inventory

    Studies of the distribution of O2 in air will inform us about critical problems in the global carbon cycle which are not readily accessed by other measurements, including the rate of seasonal net production in the oceans on a hemispheric scale, the rate at which the oceans are ta...

  3. Influences of atmospheric conditions and air mass on the ratio of ultraviolet to total solar radiation

    SciTech Connect

    Riordan, C.J.; Hulstrom, R.L.; Myers, D.R.

    1990-08-01

    The technology to detoxify hazardous wastes using ultraviolet (UV) solar radiation is being investigated by the DOE/SERI Solar Thermal Technology Program. One of the elements of the technology evaluation is the assessment and characterization of UV solar radiation resources available for detoxification processes. This report describes the major atmospheric variables that determine the amount of UV solar radiation at the earth's surface, and how the ratio of UV-to-total solar radiation varies with atmospheric conditions. These ratios are calculated from broadband and spectral solar radiation measurements acquired at SERI, and obtained from the literature on modeled and measured UV solar radiation. The following sections discuss the atmospheric effects on UV solar radiation and provide UV-to-total solar radiation ratios from published studies, as well as measured values from SERI's data. A summary and conclusions are also given.

  4. Air/fuel ratio controller

    SciTech Connect

    Schechter, M.M.; Simko, A.O.

    1980-12-23

    An internal combustion engine has a fuel injection pump and an air/fuel ratio controller. The controller has a lever that is connected to the pump lever. An aneroid moves the controller lever as a function of changes in intake manifold vacuum to maintain a constant air/fuel ratio to the mixture charge. A fuel enrichment linkage is provided that modifies the movement of the fuel flow control lever by the aneroid in response to changes in manifold gas temperature levels and exhaust gas recirculation to maintain the constant air/fuel ratio. A manual override is provided to obtain a richer air/fuel ratio for maximum acceleration.

  5. Properties of air mass mixing and humidity in the subtropics from measurements of the D/H isotope ratio of water vapor at the Mauna Loa Observatory

    NASA Astrophysics Data System (ADS)

    Noone, David; Galewsky, Joseph; Sharp, Zachary D.; Worden, John; Barnes, John; Baer, Doug; Bailey, Adriana; Brown, Derek P.; Christensen, Lance; Crosson, Eric; Dong, Feng; Hurley, John V.; Johnson, Leah R.; Strong, Mel; Toohey, Darin; van Pelt, Aaron; Wright, Jonathon S.

    2011-11-01

    Water vapor in the subtropical troposphere plays an important role in the radiative balance, the distribution of precipitation, and the chemistry of the Earth's atmosphere. Measurements of the water vapor mixing ratio paired with stable isotope ratios provide unique information on transport processes and moisture sources that is not available with mixing ratio data alone. Measurements of the D/H isotope ratio of water vapor from Mauna Loa Observatory over 4 weeks in October-November 2008 were used to identify components of the regional hydrological cycle. A mixing model exploits the isotope information to identify water fluxes from time series data. Mixing is associated with exchange between marine boundary layer air and tropospheric air on diurnal time scales and between different tropospheric air masses with characteristics that evolve on the synoptic time scale. Diurnal variations are associated with upslope flow and the transition from nighttime air above the marine trade inversion to marine boundary layer air during daytime. During easterly trade wind conditions, growth and decay of the boundary layer are largely conservative in a regional context but contribute ˜12% of the nighttime water vapor at Mauna Loa. Tropospheric moisture is associated with convective outflow and exchange with drier air originating from higher latitude or higher altitude. During the passage of a moist filament, boundary layer exchange is enhanced. Isotopic data reflect the combination of processes that control the water balance, which highlights the utility for baseline measurements of water vapor isotopologues in monitoring the response of the hydrological cycle to climate change.

  6. Scavenging ratios based on inflow air concentrations

    SciTech Connect

    Davis, W.E.; Dana, M.T.; Lee, R.N.; Slinn, W.G.N.; Thorp, J.M.

    1991-07-01

    Scavenging ratios were calculated from field measurements made during April 1985. Event precipitation samples were collected at the surface, but air chemistry measurements in the air mass feeding the precipitation were made from an aircraft. In contrast, ratios calculated in previous studies have used air concentration and precipitation chemistry data from only surface measurements. Average scavenging ratios were calculated for SO{sub 4}{sup 2{minus}}, NO{sub 3}{sup {minus}}, NH{sub 4}{sup +}, total sulfate, total nitrate, and total ammonium for 5 events; the geometric mean of these scavenging ratios were 8.5 {times} 10{sup 5}, 5.6 {times} 10{sup 6}, 4.3 {times} 10{sup 5}, 3.4 {times} 10{sup 5}, 2.4 {times} 10{sup 6}, and 9.7 {times} 10{sup 4}, respectively. These means are similar to but less variable than previous ratios formed using only surface data.

  7. System for controlling air-fuel ratio

    SciTech Connect

    Morozumi, T.

    1982-09-14

    A system for controlling the air-fuel ratio for an internal combustion engine having an induction passage, an exhaust passage , a choke valve in the induction passage, an automatic choke device comprising a positive temperature coefficient (Ptc) heater and a bimetal element connected to the choke valve, a detector for detecting the concentration of a constituent of exhaust gases passing through the exhaust passage, an electronic control circuit, an on-off type electromagnetic valve actuated by the output signal from the electronic control circuit for correcting the air-fuel ratio of the air-fuel mixture supplied by an airfuel mixture supplier, and means for actuating the on-off type electromagnetic valve at a fixed duty ratio during cold engine operation. The electronic control circuit comprises a vacuum sensor for converting the amount of the induced air to an electric quantity, an engine temperature detector for converting the engine temperature to an electric quantity, a first calculating circuit for producing a proper desired air-fuel mixture ratio signal from the output signals of the vacuum sensor and of the engine temperature detector, and a second calculation circuit for producing an actual air-fuel ratio signal from output signals of the vacuum sensor and of the ptc heater. A summing circuit for summing the proper air-fuel ratio signal and the actual air-fuel ratio signal produces a pulse duty ratio correcting signal which is applied to the electronic control circuit for correcting the fixed duty ratio.

  8. Ratio method of measuring W boson mass

    SciTech Connect

    Guo, Feng

    2010-08-01

    This dissertation describes an alternative method of measuring the W boson mass in DØ experiment. Instead of extracting MW from the fitting of W → ev fast Monte Carlo simulations to W → ev data as in the standard method, we make the direct fit of transverse mass between W → ev data and Z → ee data. One of the two electrons from Z boson is treated as a neutrino in the calculation of transverse mass. In ratio method, the best fitted scale factor corresponds to the ratio of W and Z boson mass (MW/MZ). Given the precisely measured Z boson mass, W mass is directly fitted from W → ev and Z → ee data. This dissertation demonstrates that ratio method is a plausible method of measuring the W boson mass. With the 1 fb-1 DØ Run IIa dataset, ratio method gives MW = 80435 ± 43(stat) ± 26(sys) MeV.

  9. The mass ratio in spectroscopic binaries

    NASA Astrophysics Data System (ADS)

    Ducati, J. R.; Penteado, E. M.; Turcati, R.

    2003-08-01

    The process of formation of binary and multiple stars is not yet fully understood. Possibilities range from simultaneous processes of condensation from the primeval nebula, to isolated star formation and eventual capture to form a double system. Models exist that predict success probabilities for each theoretical process, and comparison with observational data is crucial. Spectroscopic binaries are specially suited to be used as observational data, since several biases that can arise from general catalogues of binary stars can be avoided, including dominance of systems with large separations between components. A very important parameter in these studies is the mass ratio, the quocient of the masses of primary and secundary members. The histogram of mass ratios provides crucial information to models of binary formation, linked to condensation processes and evolutionaty rates.In this case, spectroscopic binaries can be chosen as the observational sample, provided that the spectrum of the primary is from a non-evolved, main-sequence star,whose mass can be derived reliably from its spectral type. Defining an adequate limiting magnitude (6.5), one avoids bias from eclipsing systems with high inclinations, since nearly all systems up to 6.5 mag were detected. In this paper, a critical review is presented of the existing methods for deriving the distribution of the mass ratios from spectroscopic binary orbital data. After showing the incorrectness of some results published in the litterature, the available data (Batten's 8th Catalogue, 1989) is discussed. Simulations for several distributions of mass ratios (constant, quadratic, etc) are performed. It is shown that the existing data permits only to assert that the spectroscopic binaries with small mass ratios (q < 0.4) are more frequent that those with large mass ratios (q = 0.9 to 1.0).

  10. On the mass ratio of Capella

    SciTech Connect

    Batten, A.H.; Hill, G.; Lu, W. )

    1991-07-01

    High-dispersion spectrograms of Capella have been measured by cross correlation with a similar spectrogram of beta Aquarii in order to determine the velocity amplitudes of both components. A mass ratio of 1.025 {plus minus} 0.028, the component with the sharper spectral lines being marginally the more massive, is found. The total mass of the system is found to be 5.05 solar mass {plus minus} 0.12 solar mass, which is acceptably close to the value found by combining the orbital semiaxis major derived from speckle interferometry with the trigonometrical parallax. Individual masses of 2.56 solar mass {plus minus} 0.08 solar mass and 2.49 solar mass {plus minus} 0.09 solar mass are deduced. Stellar models that include convective overshooting are needed to interpret the observations and it is found, by comparison with such models, that the age of Capella is 8 {times} 10 to the 8th years. 18 refs.

  11. Controlling Gas-Flow Mass Ratios

    NASA Technical Reports Server (NTRS)

    Morris, Brian G.

    1990-01-01

    Proposed system automatically controls proportions of gases flowing in supply lines. Conceived for control of oxidizer-to-fuel ratio in new gaseous-propellant rocket engines. Gas-flow control system measures temperatures and pressures at various points. From data, calculates control voltages for electronic pressure regulators for oxygen and hydrogen. System includes commercially available components. Applicable to control of mass ratios in such gaseous industrial processes as chemical-vapor depostion of semiconductor materials and in automotive engines operating on compressed natural gas.

  12. Continuous measurements of surface water vapor isotopic ratios in the Bolivian Andes during the monsoon period: influence of regional convection and air masses mixing

    NASA Astrophysics Data System (ADS)

    Vimeux, Francoise; Tremoy, Guillaume; Roca, Manuel; Moreno, Isabel; Cattani, Olivier; Guilpart, Etienne; Velarde, Fernando; Andrade, Marcos

    2015-04-01

    The isotopic composition of surface water vapor has been monitored since October 2013 in the Bolivian Andes on the Chacaltaya GAW Station (CHC). This platform is located at 16.21degree S and 68.08 degree W (elevation 5240m a.s.l) in the north western ridge of Mount Chacaltaya. Water vapor measurements have been recorded by a Picarro instrument (L2130-i model) which is based on Wavelength-Scanned Cavity Ring Down Spectroscopy (CRDS). We focus here on the data interpretation at the synoptic scale from October 2013 to January 2014. This time period corresponds to the transition between dry and wet seasons and also includes some local and regional intense convective periods. Several processes are recorded in the isotopic composition of water vapor at the synoptic scale and two majors processes will be discussed: (1) dehydrated air parcels are mixed with moist air advected from the Amazon basin and (2) deep tropical convection over the Amazon basin produces the largest isotopic variability (up to 20 per mil in oxygen 18).

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

    NASA Astrophysics Data System (ADS)

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

    2005-09-01

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

  14. Air-fuel ratio control in a gasoline engine

    NASA Astrophysics Data System (ADS)

    Lauber, J.; Guerra, T. M.; Dambrine, M.

    2011-02-01

    The aim of this article is to design an air-fuel ratio control law for a gasoline IC engine. The air-fuel ratio is measured by a lambda sensor in the exhaust manifold. As a consequence, a variable transport delay arises in the model considered. A non-linear control approach based on a Takagi-Sugeno's model of the system is used. Then, two structures of control law are compared based on parallel distributed compensation control laws, which take into account the variable time delay. Finally, some simulations are given to show the efficiency of the developed control law.

  15. Air Pressure Controlled Mass Measurement System

    NASA Astrophysics Data System (ADS)

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

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

  16. Evaluation of Air Capture Ratio of Scramjet Inlet by Multi-Point Pressure Measurement

    NASA Astrophysics Data System (ADS)

    Kitamura, Eijiro; Mitani, Tohru; Sakuranaka, Noboru; Izumikawa, Muneo; Watanabe, Syuichi; Masuya, Goro

    A method to evaluate aerodynamic performances of scramjet engines by using multi-probe rakes was proposed. The aerodynamic tests were carried out under Mach 4 flight conditions. The Pitot and static pressures were measured at 250 points in the cross sectional area of the engine exit by the rakes. Local mass flux and thrust function were evaluated from the pressure measurement at each point and integrations of these values enabled to obtain the mass flow rate and the stream thrust at the engine exit. The air capture ratios were independently measured by the rakes and a conventional choked flowmeter. The air capture ratios measured by these two methods agreed within 2%. It was found that the rakes enabled to measure the air capture ratio more simply than the flowmeter. Additionally, the effect of boundary layer ingestion to an internal drag was investigated by the rakes. The decrease of air capture ratio measured by the rakes showed that the ingested boundary layers were separated in the inlet. The pressure drag of inlet increased by the separation and the pressure thrust decreased by the decrease of air capture ratio. As a result, the internal drag increased when the forebody boundary layer was ingested.

  17. Pulsation effects on the air fuel ratio of carburetor engines

    SciTech Connect

    Tanaka, M.; Sato, T.; Watanabe, K.

    1986-01-01

    A significant wavewise change of air fuel ratio in line with the engine speed having a long intake pipe was studied experimentally and theoretically. The results show the pulsewise change in fuel flow plays the dominant role in the wavewise change in the air fuel ratio. It is found that this pulsewise fluctuation of the fuel flow forms an oscillation wave with both the amplitude and frequency becoming larger according to the engine speed resulted by the phase change of the pulsation wave in the intake pipe according to the engine speed. A modified frequency ratio of gas vibration in the intake pipe to that of engine intake stroke is proposed to explain this pulsation effect on the fuel flow and an effective simulator for this phenomena is established.

  18. CFD assessment of orifice aspect ratio and mass flow ratio on jet mixing in rectangular ducts

    NASA Technical Reports Server (NTRS)

    Bain, D. B.; Smith, C. E.; Holdeman, J. D.

    1994-01-01

    Isothermal CFD analysis was performed on axially opposed rows of jets mixing with cross flow in a rectangular duct. Laterally, the jets' centerlines were aligned with each other on the top and bottom walls. The focus of this study was to characterize the effects of orifice aspect ratio and jet-to-mainstream mass flow ratio on jet penetration and mixing. Orifice aspect ratios (L/W) of 4-to-1, 2-to-1, and 1-to-1, along with circular holes, were parametrically analyzed. Likewise, jet-to-mainstream mass flow ratios (MR) of 2.0, 0.5, and 0.25 were systematically investigated. The jet-to-mainstream momentum-flux ratio (J) was maintained at 36 for all cases, and the orifice spacing-to-duct height (S/H) was varied until optimum mixing was attained for each configuration. The numerical results showed that orifice aspect ratio (and likewise orifice blockage) had little effect on jet penetration and mixing. Based on mixing characteristics alone, the 4-to-1 slot was comparable to the circular orifice. The 4-to-1 slot has a smaller jet wake which may be advantageous for reducing emissions. However, the axial length of a 4-to-1 slot may be prohibitively long for practical application, especially for MR of 2.0. The jet-to-mainstream mass flow ratio had a more significant effect on jet penetration and mixing. For a 4-to-1 aspect ratio orifice, the design correlating parameter for optimum mixing (C = (S/H)(sq. root J)) varied from 2.25 for a mass flow ratio of 2.0 to 1.5 for a mass flow ratio of 0.25.

  19. Color-mass-to-light-ratio relations for disk galaxies

    SciTech Connect

    McGaugh, Stacy S.; Schombert, James M. E-mail: jschombe@uoregon.edu

    2014-11-01

    We combine Spitzer 3.6 μm observations of a sample of disk galaxies spanning over 10 mag in luminosity with optical luminosities and colors to test population synthesis prescriptions for computing stellar mass. Many commonly employed models fail to provide self-consistent results: the stellar mass estimated from the luminosity in one band can differ grossly from that of another band for the same galaxy. Independent models agree closely in the optical (V band), but diverge at longer wavelengths. This effect is particularly pronounced in recent models with substantial contributions from TP-AGB stars. We provide revised color-mass-to-light ratio relations that yield self-consistent stellar masses when applied to real galaxies. The B – V color is a good indicator of the mass-to-light ratio. Some additional information is provided by V – I, but neither it nor J – K{sub s} are particularly useful for constraining the mass-to-light ratio on their own. In the near-infrared, the mass-to-light ratio depends weakly on color, with typical values of 0.6 M {sub ☉}/L {sub ☉} in the K{sub s} band and 0.47 M {sub ☉}/L {sub ☉} at 3.6 μm.

  20. Air-fuel ratio control system for an automotive engine

    SciTech Connect

    Ohishi, H.

    1988-04-19

    An air-fuel ratio control system for an automotive engine is described comprising: a first lookup table storing basic fuel injection pulse widths from which one of pulse widths is derived in accordance with engine operating conditions; a second lookup table storing maximum correcting quantities for correcting a derived basic fuel injection pulse width in order to correct deviation of air-fuel ratio due to change of a characteristic of a device used in the engine; first means for producing a necessary correcting quantity by multiplying a learning coefficient and a maximum correcting quantity derived from the second lookup table; second means for producing a desired fuel injection pulse width in accordance with the necessary correcting quantity and the derived basic fuel injection pulse width.

  1. New Method of Estimating Binary's Mass Ratios by Using Superhumps

    NASA Astrophysics Data System (ADS)

    Kato, Taichi; Osaki, Yoji

    2013-12-01

    We propose a new dynamical method of estimating binary's mass ratios by using the period of superhumps in SU UMa-type dwarf novae during the growing stage (the stage A superhumps). This method is based on the working hypothesis that the period of superhumps in the growing stage is determined by the dynamical precession rate at the 3:1 resonance radius, and is suggested in our new interpretation of the superhump period evolution during a superoutburst (2013, PASJ, 65, 95). By comparing objects having known mass ratios, we show that our method can provide sufficiently accurate mass ratios comparable to those obtained by eclipse observations in quiescence. One of the advantages of this method is that it requires neither an eclipse nor any experimental calibration. It is particularly suitable for exploring the low mass-ratio end of the evolution of cataclysmic variables, where the secondary is not detectable by conventional methods. Our analysis suggests that previous determinations of the mass ratio by using superhump periods during a superoutburst were systematically underestimated for low mass-ratio systems, and we provided a new calibration. It reveals that most WZ Sge-type dwarf novae have either secondaries close to the border of the lower main-sequence or brown dwarfs, and most of the objects have not yet reached the evolutionary stage of period bouncers. Our results are not in contradiction with an assumption that an observed minimum period (˜77 min) of ordinary hydrogen-rich cataclysmic variables is indeed the minimum period. We highlight how important the early observation of stage A superhumps is, and propose an effective future strategy of observation.

  2. Heuristic judgment of mass ratio in two-body collisions.

    PubMed

    Gilden, D L; Proffitt, D R

    1994-12-01

    The logic of judging relative mass from a two-body collision is developed from data presented by Runeson and Vedeler (1993). Data from two experiments are analyzed on a point-by-point basis, and strong support for the theory that mass-ratio judgments are mediated by separate speed and angle heuristics is shown. This analysis is accomplished by reducing the collision event to two elementary features: the presence of ricochet and the ratio of exit speeds. The heuristics that both ricochet and greater exit speed specify relative lightness are shown to explain the basic patterns of data presented by Runeson and Vedeler. PMID:7816541

  3. High-Compression-Ratio; Atkinson-Cycle Engine Using Low-Pressure Direct Injection and Pneumatic-Electronic Valve Actuation Enabled by Ionization Current and Foward-Backward Mass Air Flow Sensor Feedback

    SciTech Connect

    Harold Schock; Farhad Jaberi; Ahmed Naguib; Guoming Zhu; David Hung

    2007-12-31

    This report describes the work completed over a two and one half year effort sponsored by the US Department of Energy. The goal was to demonstrate the technology needed to produce a highly efficient engine enabled by several technologies which were to be developed in the course of the work. The technologies included: (1) A low-pressure direct injection system; (2) A mass air flow sensor which would measure the net airflow into the engine on a per cycle basis; (3) A feedback control system enabled by measuring ionization current signals from the spark plug gap; and (4) An infinitely variable cam actuation system based on a pneumatic-hydraulic valve actuation These developments were supplemented by the use of advanced large eddy simulations as well as evaluations of fuel air mixing using the KIVA and WAVE models. The simulations were accompanied by experimental verification when possible. In this effort a solid base has been established for continued development of the advanced engine concepts originally proposed. Due to problems with the valve actuation system a complete demonstration of the engine concept originally proposed was not possible. Some of the highlights that were accomplished during this effort are: (1) A forward-backward mass air flow sensor has been developed and a patent application for the device has been submitted. We are optimistic that this technology will have a particular application in variable valve timing direct injection systems for IC engines. (2) The biggest effort on this project has involved the development of the pneumatic-hydraulic valve actuation system. This system was originally purchased from Cargine, a Swedish supplier and is in the development stage. To date we have not been able to use the actuators to control the exhaust valves, although the actuators have been successfully employed to control the intake valves. The reason for this is the additional complication associated with variable back pressure on the exhaust valves when

  4. Mass-to-luminosity ratio in binary galaxies

    NASA Astrophysics Data System (ADS)

    de Freitas Pacheco, J. A.; Junqueira, Selma

    1988-11-01

    The authors have compared the observed distribution of the quantity log (Vz2rP) for a sample of 233 pairs of galaxies with Monte-Carlo simulations. They have derived an average mass-to-luminosity ratio M/LB = 18±11. The result is consistent with a linear increase of the mass with radius at least until distances of about 30 kpc.

  5. Is the Binary Mass Ratio Distribution Separation-Dependent?

    NASA Astrophysics Data System (ADS)

    Gullikson, Kevin; Kraus, Adam L.

    2016-01-01

    Recent discoveries of planets orbiting retired A-stars on close orbits and young A-stars on very wide orbits have renewed interest in the properties of nearby intermediate-mass stars. Especially interesting are the young stars because directly-imaged planets orbiting them may be bright enough for characterization (e.g. HR 8799, Beta Pictoris, etc). However, intermediate-mass stars and especially young intermediate mass stars are part of multiple systems more often than not. Close stellar companions may affect the formation and orbital evolution of any planets, and the properties of the companions can help constrain the binary formation mechanism. The mass ratio distribution of a population of binary stars, especially if the distribution for close companions is significantly different from that of wide companions, is helpful to distinguish companions that were born in or affected by the circumstellar disk from those which formed through fragmentation of the molecular core. Previous imaging surveys have found that binary systems with A-type primary stars tend to have cool companions with extreme mass ratios. There are hints at a much flatter mass ratio distribution for close companions, but strong completeness effects complicate the picture. We have conducted a spectroscopic survey of ~400 nearby main sequence A- and B-type stars, aimed at detecting stellar companions as late as M4 for all orbital separations <100 AU. We have searched for companions to the stars by cross-correlating the spectra against model templates for F-M type stars; a significant peak in the cross-correlation function indicates a detection. Our cross-correlation technique can detect low-mass companions with orbits that are too wide to detect with radial velocity monitoring and too small to detect with imaging techniques, making it complementary to work already done. We will present results from our survey and compare the mass ratio distribution we measure to the corresponding distribution for

  6. Make phthalic anhydride with low air ratio process

    SciTech Connect

    Verde, L.; Nari, A.

    1984-11-01

    A new process for the production of phthalic anhydride from o-xylene has been developed by Alusuisse Italia S.p.A. and is now being implemented in one of the two large reactors (15,500 tubes each) of Ftalital, Division of Alusuisse Italia. The main advantages of the new technology in comparison with the best current technology (the low energy process are essentially the following: An increase of the catalyst productivity by more than 40% A reduction of weight air/o-xylene ratio from 20:1 to 9.5:1 (corresponding to an increase in o-xylene concentration in air from 65 g/Nm/sup 3/ to 134 g/Nm/sup 3/); A consequent reduction of both capital investment and energy consumption, which contribute to reducing the transfer price of production of phthalic anhydride by more than US$40 per metric ton, at the present prevailing raw material and utilities costs. The new technology at low air ratio (LAR Process) was predicted upon the development of a new catalyst formulation specifically adapted to the purpose. This required about two years of research work in laboratories and pilot facilities of Alusuisse Italia.

  7. BINARY FORMATION MECHANISMS: CONSTRAINTS FROM THE COMPANION MASS RATIO DISTRIBUTION

    SciTech Connect

    Reggiani, Maddalena M.; Meyer, Michael R.

    2011-09-01

    We present a statistical comparison of the mass ratio distribution of companions, as observed in different multiplicity surveys, to the most recent estimate of the single-object mass function. The main goal of our analysis is to test whether or not the observed companion mass ratio distribution (CMRD) as a function of primary star mass and star formation environment is consistent with having been drawn from the field star initial mass function (IMF). We consider samples of companions for M dwarfs, solar-type stars, and intermediate-mass stars, both in the field as well as clusters or associations, and compare them with populations of binaries generated by random pairing from the assumed IMF for a fixed primary mass. With regard to the field we can reject the hypothesis that the CMRD was drawn from the IMF for different primary mass ranges: the observed CMRDs show a larger number of equal-mass systems than predicted by the IMF. This is in agreement with fragmentation theories of binary formation. For the open clusters {alpha} Persei and the Pleiades we also reject the IMF random-pairing hypothesis. Concerning young star-forming regions, currently we can rule out a connection between the CMRD and the field IMF in Taurus but not in Chamaeleon I. Larger and different samples are needed to better constrain the result as a function of the environment. We also consider other companion mass functions and we compare them with observations. Moreover the CMRD both in the field and clusters or associations appears to be independent of separation in the range covered by the observations. Combining therefore the CMRDs of M (1-2400 AU) and G (28-1590 AU) primaries in the field and intermediate-mass primary binaries in Sco OB2 (29-1612 AU) for mass ratios, q = M{sub 2}/M{sub 1}, from 0.2 to 1, we find that the best chi-square fit follows a power law dN/dq{proportional_to}q {sup {beta}}, with {beta} = -0.50 {+-} 0.29, consistent with previous results. Finally, we note that the

  8. Binary Formation Mechanisms: Constraints from the Companion Mass Ratio Distribution

    NASA Astrophysics Data System (ADS)

    Reggiani, Maddalena M.; Meyer, Michael R.

    2011-09-01

    We present a statistical comparison of the mass ratio distribution of companions, as observed in different multiplicity surveys, to the most recent estimate of the single-object mass function. The main goal of our analysis is to test whether or not the observed companion mass ratio distribution (CMRD) as a function of primary star mass and star formation environment is consistent with having been drawn from the field star initial mass function (IMF). We consider samples of companions for M dwarfs, solar-type stars, and intermediate-mass stars, both in the field as well as clusters or associations, and compare them with populations of binaries generated by random pairing from the assumed IMF for a fixed primary mass. With regard to the field we can reject the hypothesis that the CMRD was drawn from the IMF for different primary mass ranges: the observed CMRDs show a larger number of equal-mass systems than predicted by the IMF. This is in agreement with fragmentation theories of binary formation. For the open clusters α Persei and the Pleiades we also reject the IMF random-pairing hypothesis. Concerning young star-forming regions, currently we can rule out a connection between the CMRD and the field IMF in Taurus but not in Chamaeleon I. Larger and different samples are needed to better constrain the result as a function of the environment. We also consider other companion mass functions and we compare them with observations. Moreover the CMRD both in the field and clusters or associations appears to be independent of separation in the range covered by the observations. Combining therefore the CMRDs of M (1-2400 AU) and G (28-1590 AU) primaries in the field and intermediate-mass primary binaries in Sco OB2 (29-1612 AU) for mass ratios, q = M 2/M 1, from 0.2 to 1, we find that the best chi-square fit follows a power law dN/dqvpropq β, with β = -0.50 ± 0.29, consistent with previous results. Finally, we note that the Kolmogorov-Smirnov test gives a ~1% probability

  9. High Resolution Double-Focusing Isotope Ratio Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Radke, J.; Deerberg, M.; Hilkert, A.; Schlüter, H.-J.; Schwieters, J.

    2012-04-01

    In recent years isotope ratio mass spectrometry has extended to the capability of quantifying very small isotope signatures related with low abundances and simultaneously detecting molecular masses such as isotopomers and isotopologues containing clumped isotopes. Some of those applications are limited by molecular interferences like different gas molecules with the same nominal mass, e.g. Ar/O2, adducts of the same molecule or of different molecules, and very small isotope abundances. The Thermo Scientific MAT 253 ULTRA is the next generation of high precision gas isotope ratio mass spectrometry, which combines a 10 KV gas ionization source (Thermo Scientific MAT 253) with a double focusing multi-collector mass analyzer (Thermo Scientific Neptune) and reduces those limitations by measuring isotope ratios on a larger dynamic range with high precision. Small ion beam requirements and high sensitivity are achieved by signal-to-noise improvements through enhanced ion beam amplification in faraday cups and ion counters. Interfering backgrounds, e.g. interfering isotopologues or isobaric ions of contaminants, are dramatically decreased by a dynamic range increase combined with high evacuation leading to undisturbed ion transmission through the double-focusing analyser. Furthermore, automated gain calibration for mathematical baseline corrections, switchable detector arrays, ion source control, analyser focusing and full data export is controlled under Isodat data control. New reference/sample strategies are under investigation besides incorporation of the continuous-flow technique and its versatile inlet devices. We are presenting first results and applications of the MAT 253 Ultra.

  10. The Charon-Pluto mass ratio from MKO astrometry

    NASA Technical Reports Server (NTRS)

    Young, L. A.; Olkin, C. B.; Elliot, J. L.; Tholen, D. J.; Buie, M. W.

    1994-01-01

    Using the University of Hawaii (UH) 2.2-m telescope, we obtained charge coupled device (CCD) images of Pluto as it passed through a single field of 10 stars during 6 nights of Charon's 6.4-day orbital period. From these data, Charon's orbital semimajor axis is found to be 19,460 +/- 58 km, which is consistent with the recent measurement by Null et al. (1993), of 19,405 +/- 86 km. Our semimajor axis implies a system mass of (14.32 +/- 0.13) x 10(exp 24) g. From the motions of Pluto and Charon around their barycenter, we find that the ratio of Charon's mass to Pluto's is 0.1566 +/- 0.0035, indicating that the bodies both have densities near 2 g/cc. Our ratio is nearly twice that of Null et al., who find a ratio of 0.0837 +/- 0.0147. Possible reasons for the large discrepancy are discussed.

  11. Failsafe device for air/fuel ratio feedback control system

    SciTech Connect

    Otsuka, K.; Hasegawa, S.; Narasaka, S.

    1983-11-15

    A fail safe device is disclosed, comprising means for detecting a failure in an air/fuel ratio feedback control system and generating a fault signal when such failure is detected, and means responsive to the fault signal to drive an actuator for driving an air/fuel ratio control valve and also responsive to a reference position signal supplied thereto during the above driving, which is generated when the actuator passes its reference position, to stop the actuator at the reference position. The actuator driving/stopping means may comprise means for repeatedly driving the actuator over a predetermined operating range inclusive of the reference position a plurality of times when it is not supplied with the reference position signal upon the actuator passing the reference position, and means for driving the actuator from its extreme operating position to a predetermined position and holding the same there when it is not supplied with the reference position signal even after a predetermined number of times of the above repeated driving of the actuator.

  12. GUT predictions for quark and lepton mass ratios

    SciTech Connect

    Antusch, S.; Spinrath, M.

    2010-02-10

    Group theoretical factors from GUT symmetry breaking can lead to predictions for the ratios of quark and lepton masses at the unification scale. Due to supersymmetric (SUSY) threshold corrections the viability of such predictions can depend strongly on the SUSY parameters. We derive possible new predictions for the GUT scale ratios m{sub m}u/m{sub s}, ytau/y{sub b} and y{sub t}/y{sub b} and compare them with the experimentally allowed ranges for three common SUSY breaking scenarios.

  13. Isotope ratio mass spectrometry - history and terminology in brief.

    PubMed

    Flenker, Ulrich

    2012-12-01

    The history of isotope ratio mass spectrometry (IRMS) is briefly described. It is shown that the fundamental design of isotope ratio mass spectrometers has not changed since the 1940s. The basic findings concerning the natural variation of isotope abundances even date back to the 1930s. Recent improvements in the methodology mainly concern online coupling and analytical peripherals. The nature of isotopic scales necessitates a specific terminology which is unfamiliar to many analysts. However, corresponding guidelines exist that should be adopted by the anti-doping community. Currently, steroids represent the only group of compounds routinely analyzed by IRMS in doping-control. Suggestions are made in respect to a harmonized terminology concerning the nature and origins of steroids. PMID:22972693

  14. The Effective Mass of a Ball in the Air

    ERIC Educational Resources Information Center

    Messer, J.; Pantaleone, J.

    2010-01-01

    The air surrounding a projectile affects the projectile's motion in three very different ways: the drag force, the buoyant force, and the added mass. The added mass is an increase in the projectile's inertia from the motion of the air around it. Here we experimentally measure the added mass of a spherical projectile in air. The results agree well…

  15. Binary accretion rates: dependence on temperature and mass ratio

    NASA Astrophysics Data System (ADS)

    Young, M. D.; Clarke, C. J.

    2015-09-01

    We perform a series of 2D smoothed particle hydrodynamics simulations of gas accretion on to binaries via a circumbinary disc, for a range of gas temperatures and binary mass ratios (q). We show that increasing the gas temperature increases the accretion rate on to the primary for all values of the binary mass ratio: for example, for q = 0.1 and a fixed binary separation, an increase of normalized sound speed by a factor of 5 (from our `cold' to `hot' simulations) changes the fraction of the accreted gas that flows on to the primary from 10 to ˜40 per cent. We present a simple parametrization for the average accretion rate of each binary component accurate to within a few per cent and argue that this parametrization (rather than those in the literature based on warmer simulations) is relevant to supermassive black hole accretion and all but the widest stellar binaries. We present trajectories for the growth of q during circumbinary disc accretion and argue that the period distribution of stellar `twin' binaries is strong evidence for the importance of circumbinary accretion. We also show that our parametrization of binary accretion increases the minimum mass ratio needed for spin alignment of supermassive black holes to q ˜ 0.4, with potentially important implications for the magnitude of velocity kicks acquired during black hole mergers.

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

    NASA Astrophysics Data System (ADS)

    Hornik, Alexander

    1992-04-01

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

  17. Effect of fuel-air-ratio nonuniformity on emissions of nitrogen oxides

    NASA Technical Reports Server (NTRS)

    Lyons, V. J.

    1981-01-01

    The inlet fuel-air ratio nonuniformity is studied to deterine how nitrogen oxide (NOx) emissions are affected. An increase in NOx emissions with increased fuel-air ratio nonuniformity for average equivalence ratios less than 0.7 and a decrease in NOx emissions for average equivalence ratios near stoichiometric is predicted. The degree of uniformityy of fuel-air ratio profiles that is necessary to achieve NOx emissions goals for actual engines that use lean, premixed, prevaporized combustion systems is determined.

  18. Air-fuel ratio control system for an internal combustion engine

    SciTech Connect

    Nishimura, T.; Suzuki, M.

    1981-09-29

    The air-fuel ratio for an internal combustion engine is controlled at the three stages: (A) when the engine temperature is lower than a first predetermined value, the air-fuel ratio is controlled only by a choke valve, (B) when the engine is at a temperature of the first predetermined value to a second predetermined value, the air-fuel ratio is controlled according to the output signals of engine temperature detecting means, and (C) when the engine temperature is higher than the second predetermined value, the air-fuel ratio is controlled according to the signals from air-fuel ratio detecting means.

  19. Water D/H Ratio In Low-Mass Protostars

    NASA Astrophysics Data System (ADS)

    Persson, Magnus V.; Jørgensen, Jes K.; van Dishoeck, Ewine F.; Harsono, Daniel

    2013-07-01

    Water is an important molecule for our life on Earth, but its way from formation on the surfaces of dust grains to planets and the accompanying chemical processing are not well understood. Through evaporation in the warm inner regions of protostars, water brings complex organics and other species previously locked up in the ice into the gas phase. The water deuterium fractionation (HDO/H2O abundance ratio) has traditionally been used to infer the amount of water that was brought to the Earth by comets. Deducing this ratio in the warm gas of deeply-embedded low-mass protostars allows to extend the discussion of the origin of Earth's water to earlier evolutionary stages. This poster present high-angular resolution, ground based interferometric observations of both HDO and H2(18)O water isotopologues toward several Class~0 low-mass protostars. The emission is compact, and stems from the inner few 100 AU in all sources. The derived amount of deuterium fractionation in water, obtained assuming LTE and optically thin emission, is the same within the uncertainties in all sources and shows only small enhancements compared with Earth's oceans and solar system's comets.

  20. Use of fluidic oscillator to measure fuel-air ratios of combustion gases

    NASA Technical Reports Server (NTRS)

    Riddlebaugh, S. M.

    1974-01-01

    A fluidic oscillator was investigated for use in measuring fuel-air ratios in hydrocarbon combustion processes. The oscillator was operated with dry exhaust gas from an experimental combustor burning ASTM A-1 fuel. Tests were conducted with fuel-air ratios between 0.015 and 0.031. Fuel-air ratios determined by oscillator frequency were within 0.001 of the values computed from separate flow measurements of the air and fuel.

  1. The Close Companion Mass-ratio Distribution of Intermediate-mass Stars

    NASA Astrophysics Data System (ADS)

    Gullikson, Kevin; Kraus, Adam; Dodson-Robinson, Sarah

    2016-08-01

    Binary stars and higher-order multiple systems are a ubiquitous outcome of star formation, especially as the system mass increases. The companion mass-ratio distribution is a unique probe into the conditions of the collapsing cloud core and circumstellar disk(s) of the binary fragments. Inside a˜ 1000 {{A}}{{U}} the disks from the two forming stars can interact, and additionally companions can form directly through disk fragmentation. We should, therefore, expect the mass-ratio distribution of close companions (a≲ 100 AU) to differ from that of wide companions. This prediction is difficult to test using traditional methods, in particular, with intermediate-mass primary stars, for a variety of observational reasons. We present the results of a survey searching for companions to A- and B-type stars using the direct spectral detection method, which is sensitive to late-type companions within ˜ 1\\prime\\prime of the primary and which has no inner working angle. We estimate the temperatures and surface gravity of most of the 341 sample stars and derive their masses and ages. We additionally estimate the temperatures and masses of the 64 companions we find, 23 of which are new detections. We find that the mass-ratio distribution for our sample has a maximum near q˜ 0.3. Our mass-ratio distribution has a very different form than in previous works, where it is usually well-described by a power law, and indicates that close companions to intermediate-mass stars experience significantly different accretion histories or formation mechanisms than wide companions.

  2. The effect of fuel-to-air ratio on burner-rig hot corrosion

    NASA Technical Reports Server (NTRS)

    Deadmore, D. L.; Lowell, C. E.; Kohl, F. J.

    1978-01-01

    Samples of a cobalt-base alloy, Mar M-509, were subjected to hot corrosion in a Mach-0.3 burner rig. The corrodent was NaCl added as an aqueous solution to the combustion products of a sulfur-containing Jet-A fuel. The metal temperature was fixed at 900 C. The extent of hot corrosion increased by a factor of three as the fuel-to-air mass ratio was increased from 0.033 to 0.050. Because the depositing salt was always Na2SO4, the increased attack appeared to be related to the gas composition.

  3. Isotope Ratio Monitoring Gas Chromatography Mass Spectrometry (IRM-GCMS)

    NASA Technical Reports Server (NTRS)

    Freeman, K. H.; Ricci, S. A.; Studley, A.; Hayes, J. M.

    1989-01-01

    On Earth, the C-13 content of organic compounds is depleted by roughly 13 to 23 permil from atmospheric carbon dioxide. This difference is largely due to isotope effects associated with the fixation of inorganic carbon by photosynthetic organisms. If life once existed on Mars, then it is reasonable to expect to observe a similar fractionation. Although the strongly oxidizing conditions on the surface of Mars make preservation of ancient organic material unlikely, carbon-isotope evidence for the existence of life on Mars may still be preserved. Carbon depleted in C-13 could be preserved either in organic compounds within buried sediments, or in carbonate minerals produced by the oxidation of organic material. A technique is introduced for rapid and precise measurement of the C-13 contents of individual organic compounds. A gas chromatograph is coupled to an isotope-ratio mass spectrometer through a combustion interface, enabling on-line isotopic analysis of isolated compounds. The isotope ratios are determined by integration of ion currents over the course of each chromatographic peak. Software incorporates automatic peak determination, corrections for background, and deconvolution of overlapped peaks. Overall performance of the instrument was evaluated by the analysis of a mixture of high purity n-alkanes of know isotopic composition. Isotopic values measured via IRM-GCMS averaged withing 0.55 permil of their conventionally measured values.

  4. Effects of nozzle exit geometry and pressure ratio on plume shape for nozzles exhausting into quiescent air

    NASA Technical Reports Server (NTRS)

    Scallion, William I.

    1991-01-01

    The effects of varying the exit geometry on the plume shapes of supersonic nozzles exhausting into quiescent air at several exit-to-ambient pressure ratios are given. Four nozzles having circular throat sections and circular, elliptical and oval exit cross sections were tested and the exit plume shapes are compared at the same exit-to-ambient pressure ratios. The resulting mass flows were calculated and are also presented.

  5. A New Multi Collector Isotope Ratio Mass Spectrometer

    NASA Astrophysics Data System (ADS)

    Appelhans, A. D.; Olson, J. E.; Ward, M. B.; Dahl, D. A.

    2007-12-01

    With the goal of improving the sensitivity of isotope ratio measurements, particularly for actinides, a new magnetic sector mass spectrometer that utilizes up to seven full-sized discrete dynode electron multipliers operating simultaneously has been designed, constructed and is in the early stages of testing. The design is based on a newly developed ion dispersion lens that enables the mass dispersed individual isotope beams to be separated by 35 mm; this allows a full-sized discrete dynode pulse counting multiplier to be used for each beam. The ion dispersion lens (US patents 6,297,501 and pending) is a two element electrostatic 90 degree sector device that causes the beam-to-beam dispersion to increase faster than the intra-beam dispersion. Each of the multipliers is housed in an isolated case and is equipped with a deflector/condenser lens at the entrance to optimize pulse generation. The instrument includes a 9-sample filament cartridge mounted on a micro-manipulator X-Y stage that enables adjustment of the filament position with 10 micron resolution within the ion lens. Initial testing has shown that the instrument is performing as predicted by the ion optics model of the design.

  6. The low mass ratio contact binary system V728 Herculis

    NASA Astrophysics Data System (ADS)

    Erkan, N.; Ulaş, B.

    2016-07-01

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

  7. Measuring the Mass-to-Light Ratio of Cluster Galaxies

    NASA Astrophysics Data System (ADS)

    Natarajan, P.

    1996-12-01

    There is ample evidence from lensing for the clumping of dark matter on different scales within clusters, although the spatial extent of dark halos of cluster galaxies are yet to be constrained. The issue is of crucial importance as it addresses the key question of whether the mass to light ratio of galaxies is a function of the environment, and if it is indeed significantly different in the high density regions like cluster cores as opposed to the field. Weak shear maps of the outer regions of clusters have been successfully used to map the distribution of mass at large radii. However the typical smoothing lengths generally employed preclude the systematic study of the effects of galactic-scale substructure on the measured weak lensing signal. We present two new methods to study the effect of bright cluster galaxies on the cluster weak shear field - aperture averaging of the local shear and a maximum likelihood method to obtain limits on parameters that characterize galaxy halos. The composite lensing effect of a cluster is modeled by the superposition of mass clumps with different scales: a large-scale clump to describe the cluster and smaller scale ones for individual cluster galaxies. Working in the local frame of each perturber, the shear induced by the larger scale component can be efficiently subtracted, yielding the averaged shear field induced by the smaller-scale mass component. Cluster galaxy halos are modeled using simple scaling relations and the background high redshift population is modeled in consonance with observations from redshift surveys and lensing constraints. We demonstrate using simulations that these observed local weak-shear effects on galaxy scales within the cluster can be used to statistically constrain reliably the mean M/L of cluster members, and fiducial parameters like the halo size, velocity dispersion and hence mass of cluster galaxies. The results of the members, and fiducial parameters like the halo size and the velocity

  8. Mass-energy absorption coefficient and backscatter factor ratios for kilovoltage x-ray beams

    NASA Astrophysics Data System (ADS)

    Ma, C.-M.; Seuntjens, J. P.

    1999-01-01

    For low-energy (up to 150 kV) x-rays, the ratio of mass-energy absorption coefficients for water to air, , and the backscatter factor B are used in the conversion of air kerma, measured free-in-air, to water kerma on the surface of a water phantom. For clinical radiotherapy, similar conversion factors are needed for the determination of the absorbed dose to biological tissues on (or near) the surface of a human body. We have computed the ratios and B factor ratios for different biological tissues including muscle, soft tissue, lung, skin and bone relative to water. The ratios were obtained by integrating the respective mass-energy absorption coefficients over the in-air primary photon spectra. We have also calculated the ratios at different depths in a water phantom in order to convert the measured in-phantom water kerma to the absorbed dose to various biological tissues. The EGS4/DOSIMETER Monte Carlo code system has been used for the simulation of the energy fluence at different depths in a water phantom irradiated by a kilovoltage x-ray beam of variable beam quality (HVL: 0.1 mm Al-5 mm Cu), field size and source-surface distance (SSD). The same code was also used in the calculation of the B factor ratios, soft tissue to water and bone to water. The results show that the B factor for bone differs from the B factor for water by up to 20% for a 100 kV beam (HVL: 2.65 mm Al) with a 100 field. On the other hand, the difference in the B factor between water and soft tissue is insignificant (well within 1% generally). This means that the B factors for water may be directly used to

  9. Air-fuel ratio control system for internal combustion engines capable of controlling air-fuel ratio in accordance with degree of warming-up of the engines

    SciTech Connect

    Hibino, Y.; Fukuzawa, T.

    1988-06-28

    This patent describes an air-fuel ratio control system for an internal combustion engine, the system having an automatic choke valve arranged in an intake passage of the engine, and exhaust gas sensor arranged in an exhaust passage of the engine and having an output characteristic linear with respect to the concentration of a specific component in exhaust gases from the engine, an air passage bypassing a throttle valve in the intake passage, an air-fuel ratio control valve arranged in the air passage, and disposed to be driven in response to an output from the exhaust gas sensor for controlling the air-fuel ratio of a mixture supplied to the engine, and temperature sensing means for sensing the degree of warming-up of the engine, the combination comprising; determining means for determining whether the exhaust gas has been activated; means for controlling the opening of the automatic choke valve in response to the degree of warming-up of the engine sensed by the temperature sensing means while the determining means determines that the exhaust gas sensor is inactive; means for determining the difference between a desired value of the air-fuel ratio and an actual value thereof sensed by the exhaust gas sensor, and for driving the automatic choke valve when the determined difference is larger than a predetermined value, and the air-fuel ratio control valve when the determined difference is smaller than the predetermined value, respectively, from the time the determining means determines for the first time that the exhaust gas sensor has become activated to the time the temperature sensing means detects completion of warming up of the engine; and means for driving the air-fuel ratio control valve in response to operating conditions of the engine so as to achieve a desired value of the air-fuel ratio, after the temperature sensing means detects completion of warming-up of the engine.

  10. Effect of mass ratio on hydrodynamic response of a flexible cylinder

    NASA Astrophysics Data System (ADS)

    Cen, Haoyang; Carriveau, Rupp; Ting, David S.-K.

    2016-03-01

    The effect of the mass ratio on the flow-induced vibration (FIV) of a flexible circular cylinder is experimentally investigated in a towing tank. A Tygon tube with outer and inner diameters of 7.9 mm and 4.8 mm, respectively, was employed for the study. The tube was connected to a carriage and towed from rest to a steady speed up to 1.6 m/s before slowing down to rest again over a distance of 1.6 m in still water. Reynolds number based on the cylinder's outer diameter was 800-13,000, and the reduced velocity (velocity normalized by the cylinder's natural frequency and outer diameter) spanned from 2 to 25. When connected, the cylinder was elongated from 420 mm to 460 mm under an axial pre-tension of 11 N. Based on the cylinder's elongated length, the aspect ratio (ratio of the cylinder's length to outer diameter) was calculated as 58. Three mass ratios (ratio of the cylinder's structural mass to displaced fluid mass, m*) of 0.7, 1.0, and 3.4 were determined by filling the cylinder's interior with air, water, and alloy powder (nickel-chromium-boron matrix alloy), respectively. An optical method was adopted for response measurements. Multi-frequency vibrations were observed in both in-line (IL) and cross-flow (CF) responses; at high Reynolds number, vibration modes up to the 3rd one were identified in the CF response. The mode transition was found to occur at a lower reduced velocity for the highest tested mass ratio. The vibration amplitude and frequency were quantified and expressed with respect to the reduced velocity. A significant reduced vibration amplitude was found in the IL response with increasing mass ratios, and only initial and upper branches existed in the IL and CF response amplitudes. The normalized response frequencies were revealed to linearly increase with respect to the reduced velocity, and slopes for linear relations were found to be identical for the three cases tested.

  11. Approximate methods for building extreme mass ratio inspiral waveforms

    NASA Astrophysics Data System (ADS)

    Hughes, Scott

    2007-04-01

    The ``extreme mass ratio inspiral'' (or EMRI) problem has captured much attention in recent years. This is due to its relevance at describing a potentially important gravitational-wave source, and to the elegance of techniques which are being developed to solve it. A complete, self-consistent solution to this problem will require detailed knowledge of the self-interaction of a small body orbiting a Kerr black hole, taken (at least in part) to second order. This challenge will consume much time and effort. In the meantime, there is an exigent need for waveforms which, though not correct in all details, are sufficiently reliable that they can be used to understand how to measure these waves with space-based gravitational-wave antennae. I will describe in this talk results from a crude but surprisingly effective ``kludge'' approximation. The kludge produces waves which match well with available strong-field results, requiring only a fraction of the computational effort. Motivated by how the kludge operates, I will argue that a good medium between the kludge and the full solution is a ``hybrid'' approach to waveform generation. This hybrid combines the best features of both time and frequency domain approaches to black hole perturbation theory, using them to make EMRI waves that are as accurate as is possible without incorporating self-force information.

  12. Sex ratios of births, mortality, and air pollution: can measuring the sex ratios of births help to identify health hazards from air pollution in industrial environments?

    PubMed Central

    Williams, F L; Ogston, S A; Lloyd, O L

    1995-01-01

    OBJECTIVES--To compare the sex ratios of births and mortality in 12 Scottish localities with residential exposure to pollution from a variety of industrial sources with those in 12 nearby and comparable localities without such exposure. METHODS--24 localities were defined by postcode sectors. SMRs for lung cancer and for all causes of death and sex ratios of births were calculated for each locality for the years 1979-83. Log linear regression was used to assess the relation between exposure, sex ratios, and mortality. RESULTS--Mortalities from all causes were consistently and significantly higher in the residential areas exposed to air pollution than in the non-exposed areas. A similar, but less consistently significant, excess of mortality from lung cancer in the exposed areas was also found. The associations between exposure to the general air pollution and abnormal sex ratios, and between abnormal sex ratios and mortality, were negligible. CONCLUSIONS--Sex ratios were not consistently affected when the concentrations or components of the air pollution were insufficiently toxic to cause substantially increased death rates. Monitoring of the sex ratio does not provide a reliable screening measure for detecting cryptic health hazards from industrial air pollution in the general residential environment. PMID:7735388

  13. Influence of Baseline Air Masses and Wildland Fires on Air Quality in the Western United States

    NASA Astrophysics Data System (ADS)

    Wigder, Nicole L.

    This dissertation focuses on several key uncertainties related to particulate matter (PM) and O3 concentrations in the western U.S. Each analysis conducted for this dissertation centers on data collected at the Mount Bachelor Observatory (MBO, 2.8 km a.s.l., 43.98° N, 121.69° W), a mountaintop research site in central Oregon, U.S. The first component of this dissertation is an analysis of the contribution of baseline O3 to observed O3 concentrations in two western U.S. urban areas, Enumclaw, Washington (WA) and Boise, Idaho, during 2004 -- 2010. I compared O3 data from two baseline sites (MBO and Cheeka Peak, WA) to O3 concentrations in the two urban areas on days when backward air mass trajectories showed transport between the baseline and urban sites. I found that the urban areas studied had relatively low O3 on the days with a strong influence from baseline air masses (28.3 -- 48.3 ppbv). These data suggested that there was low production of O3 from urban emissions on these days, which allowed me to quantify the impact of baseline O3 on urban O3 concentrations. A regression of the Boise and MBO O3 observations showed that free tropospheric air masses were diluted by 50% as they were entrained into the boundary layer at Boise. These air masses can contain high O3 concentrations (>70 ppbv) from Asian pollution sources or stratospheric intrusions, indicating that these sources can greatly contribute to urban surface O 3 concentrations. In addition, I found that the elevation and surface temperature of the urban areas studied impacted baseline O3 concentrations in these areas, with higher elevation and greater surface temperatures leading to greater O3 concentrations. The second and third components of this dissertation are analyses of the impact of wildland fires on PM and O3 concentrations in the western U.S. For both of these analyses, I calculated pollutant enhancement ratios for PM, O3, and other species in wildland fire plumes observed at MBO during 2004

  14. Optimum air-demand ratio for maximum aeration efficiency in high-head gated circular conduits.

    PubMed

    Ozkan, Fahri; Tuna, M Cihat; Baylar, Ahmet; Ozturk, Mualla

    2014-01-01

    Oxygen is an important component of water quality and its ability to sustain life. Water aeration is the process of introducing air into a body of water to increase its oxygen saturation. Water aeration can be accomplished in a variety of ways, for instance, closed-conduit aeration. High-speed flow in a closed conduit involves air-water mixture flow. The air flow results from the subatmospheric pressure downstream of the gate. The air entrained by the high-speed flow is supplied by the air vent. The air entrained into the flow in the form of a large number of bubbles accelerates oxygen transfer and hence also increases aeration efficiency. In the present work, the optimum air-demand ratio for maximum aeration efficiency in high-head gated circular conduits was studied experimentally. Results showed that aeration efficiency increased with the air-demand ratio to a certain point and then aeration efficiency did not change with a further increase of the air-demand ratio. Thus, there was an optimum value for the air-demand ratio, depending on the Froude number, which provides maximum aeration efficiency. Furthermore, a design formula for aeration efficiency was presented relating aeration efficiency to the air-demand ratio and Froude number. PMID:25225935

  15. Experimental limit on the ratio of the gravitational mass to the inertial mass of antihydrogen

    NASA Astrophysics Data System (ADS)

    Fajans, Joel; Wurtele, Jonathan; Charman, Andrew; Zhmoginov, Andrey

    2012-10-01

    Physicists have long wondered if the gravitational interactions between matter and antimatter might be different from those between matter and itself. While there are many indirect indications that no such differences exist, i.e., that the weak equivalence principle holds, there have been no direct, free-fall style, experimental tests of gravity on antimatter. By searching for a propensity for antihydrogen atoms to fall downward when released from the ALPHA antihydrogen trap, we have determined that we can reject ratios of the gravitational mass to the inertial mass of antihydrogen greater than about 100 at a statistical significance level of 5%. A similar search places somewhat lower limits on a negative gravitational mass, i.e., on antigravity.

  16. Cryogenic separation of oxygen-argon mixture in natural air samples for isotopic and molecular ratios

    NASA Astrophysics Data System (ADS)

    Habeeb Rahman, Keedakkadan; Abe, Osamu

    2014-05-01

    The discovery of mass independent isotope fractionation in oxygen during the formation of ozone in the stratosphere has initiated a wide application in isotope geochemistry field. Separation of oxygen-argon mixture has become the foundation of high precision analysis of Δ17O and δ(O2/Ar) for geochemical applications. Here we present precise and simplified cryogenic separation of argon oxygen mixture from the atmospheric and dissolved air using 30/60 mesh 5A molecular sieve zeolite. A pioneer study of this method was conducted by Thiemens and Meagher in 1984. The column which is made of glass tube contains about 1.1 grams of molecular sieve zeolite and both ends of column was filled with glass wools. The experimental set up was tested for different combination of molecular sieves and slurry temperatures. We found the most efficient condition for the separation was at a column temperature of -103°C. For complete transfer of O2 and Ar mixture usually takes in 15-20 minutes time. The isotopic ratios of oxygen were analyzed using mass spectrometer (Thermo Fischer Delta Plus) relative to reference oxygen-argon mixture at 3V of m/z 32 for both sample and reference side. The signals of m/z 28, 32, and 40 were measured by dynamically to determine oxygen -argon ratio and to check nitrogen contamination. Repeated measurements of atmospheric air yielded a reproducibility (SE n=80) of 0.006, 0.004 and 0.19‰ for δ17O, δ18O and δO2/Ar respectively. The isotopic and molecular fractionation of argon- oxygen mixture during gas adsorption and desorption while using molecular sieve under liquid nitrogen temperature was studied. We have established a linear relationship governing the effect of 13X and 5A molecular sieves on molecular fractionation. And suggested the use of single 1/8" pellet 13X molecular sieve provided a negligible fractionation.

  17. Mass-to-Light-Ratios of the galaxy clusters and groups observed with Suzaku

    NASA Astrophysics Data System (ADS)

    Sasaki, T.; Matsushita, K.; Sato, K.; Abe, Y.; Akamatsu, H.; Fujita, Y.; Kanno, Y.; Simionescu, A.; Tamura, T.; Werner, N.

    2016-06-01

    We analyzed 15 nearby (z < 0.06 ) clusters and groups observed with Suzaku out to ˜ 2 r_{500}. We derived Fe abundance profiles in the ICM, electron density, cumulative gas mass and Fe mass. We also collected K-band luminosities of galaxies and calculated the ratio of the cumulative gas mass and Fe mass in the ICM to the K-band luminosity (gas-mass-to-light ratio and iron-mass-to-light ratio, respectively). The Coma, Perseus, and medium systems have relatively flat radial profiles of the metal abundances at 0.3 solar within 0.5-1 r_{500}, and ˜ 0.2 solar beyond r_{500}. The gas-mass-to-light-ratios and iron-mass-to-light-ratios ratios increase with radius out to r_{500} and become flatter beyond the radius. The weighted average of the iron-mass-to-light ratios of the clusters at 1.6 r_{500} agrees with the expectation with the Salpeter initial-mass-function of stars, and we do not need a top-heavy slope. In contrast, groups and poor clusters have lower gas-mass-to-light ratios and lower iron-mass-to-light ratios than that of rich systems, with the higher entropy excess. Above these results, we discuss an early metal enrichment in galaxy clusters and groups.

  18. Ultrasonic detection of solid phase mass flow ratio of pneumatic conveying fly ash

    NASA Astrophysics Data System (ADS)

    Duan, Guang Bin; Pan, Hong Li; Wang, Yong; Liu, Zong Ming

    2014-04-01

    In this paper, ultrasonic attenuation detection and weight balance are adopted to evaluate the solid mass ratio in this paper. Fly ash is transported on the up extraction fluidization pneumatic conveying workbench. In the ultrasonic test. McClements model and Bouguer-Lambert-Beer law model were applied to formulate the ultrasonic attenuation properties of gas-solid flow, which can give the solid mass ratio. While in the method of weigh balance, the averaged mass addition per second can reveal the solids mass flow ratio. By contrast these two solid phase mass ratio detection methods, we can know, the relative error is less.

  19. Influence of Ventilation Ratio on Desiccant Air Conditioning System's Efficiency Performance

    NASA Astrophysics Data System (ADS)

    Tran, Thien Nha; Akisawa, Atsushi; Kashiwagi, Takao; Hamamoto, Yoshinori

    Ventilation air is a concern for engineers since ventilated air controls indoor air contamination; additional ventilation, however, increases the energy consumption of buildings. The study investigates the energy efficiency performance of the desiccant dehumidification air conditioning system in the context of ventilation for a hot-humid climate such as summer in Japan. The investigation focuses on the variable ratio of ventilation air as required by the application of air conditioning system. The COP of the desiccant air conditioning system is determined. The evaluation is subsequently performed by comparing the desiccant based system with the conventional absorption cooling system and the vapor compression cooling system. Based on 12 desiccant rotor simulations, it is found that the desiccant regeneration temperature required varies between 47°C to 85°C as ventilation ratio increases from 0. 0 to 100%, and up to 52. 5°C as the ventilation ratio achieves 14%. The heat required for regenerating desiccant accounts for 55% and higher of the system's total heat consumption; the system is expected to be energy efficient by using wasted heat from the absorption chiller for desiccant regeneration; and its energy efficiency expands as the ratio of ventilation air rises above 15% compared with the conventional absorption cooling system. The energy efficiency also benefits as the ratio rises beyond 70% against the conventional vapor compression cooling system.

  20. Air-mass origin in the tropical lower stratosphere: The influence of Asian boundary layer air

    NASA Astrophysics Data System (ADS)

    Orbe, Clara; Waugh, Darryn W.; Newman, Paul A.

    2015-05-01

    A climatology of air-mass origin in the tropical lower stratosphere is presented for the Goddard Earth Observing System Chemistry Climate Model. During late boreal summer and fall, air-mass fractions reveal that as much as 20% of the air in the tropical lower stratosphere last contacted the planetary boundary layer (PBL) over Asia; by comparison, the air-mass fractions corresponding to last PBL contact over North America and over Europe are negligible. Asian air reaches the extratropical tropopause within a few days of leaving the boundary layer and is quasi-horizontally transported into the tropical lower stratosphere, where it persists until January. The rapid injection of Asian air into the lower stratosphere—and its persistence in the deep tropics through late (boreal) winter—is important as industrial emissions over East Asia continue to increase. Hence, the Asian monsoon may play an increasingly important role in shaping stratospheric composition.

  1. Effect of fuel to air ratio on Mach 0.3 burner rig hot corrosion of ZrO2-Y2O3 thermal barrier coatings

    NASA Technical Reports Server (NTRS)

    Hodge, P. E.

    1982-01-01

    A Mach 0.3 burner rig test program was conducted to determine how the fuel to air mass ratio affects the durability of ZrO2-Y2O3/Ni-16Cr-6Al-0.31Y thermal barrier coating systems in combustion products containing 5 ppm Na and 2 ppm V. As the fuel to air mass ratio was increased from 0.039 to 0.049, the durability of ZrO2-6Y2O3, ZrO2-8Y2O3 and ZrO2-12Y2O3 coatings decreased. ZrO2-8Y2O3 coatings were approximately 2X and 1.3X more durable than ZrO2-12Y2O3 and ZrO2-6Y2O3 coatings respectively at the fuel to air mass ratio of 0.039. The number of one hour cycles endured by ZrO2-8Y2O3 coatings varied from averages of 53 to 200 for the fuel to air mass ratios of 0.049 and 0.039, respectively. At the fuel to air mass ratio of 0.049, all ZrO2-Y2O3 coated specimens failed in 40 to 60 one hour cycles

  2. Preliminary investigation of cooling-air ejector performance at pressure ratios from 1 to 10

    NASA Technical Reports Server (NTRS)

    Ellis, C W; Hollister, D P; Sargent, A F , Jr

    1951-01-01

    Preliminary investigation was made of conical cooling air ejector at primary pressure ratios from 1 to 10. The cooling-air flow was maintained at zero and the resulting pressure variation in the shroud indicated pumping ability. The cooling-air flow was maintained at zero and the resulting pressure variation in the shroud indicated pumping ability. The gross thrust of the ejector and nozzle were compared. Several ratios of the spacing between the nozzle and shroud exit to the nozzle exit diameter were investigated for several shroud to nozzle exit diameter ratios. Maximum gross thrust loss occurred under conditions of zero cooling-air flow and was as much as 35 percent below nozzle jet thrust. For minimum thrust loss, ejector should be designed with as low diameter and spacing ratio as possible.

  3. Critical ratios for structural analysis of triacylglycerols using mass spectrometry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recent developments have finally allowed fragment behaviors using APCI-MS to be elucidated after twenty years of literature reports. Critical Ratios have been defined that correspond to various aspects of triacylglycerol (TAG) analysis, from overall degree of unsaturation to localization of fatty ac...

  4. Ions in oceanic and continental air masses

    SciTech Connect

    Tanner, D.J.; Eisele, F.L. )

    1991-01-20

    Measurements of tropospheric ions and several trace atmospheric neutral species have been performed at Cheeka Peak Research Station and at Mauna Loa Observatory. Two new positive ion species at masses 114 and 102 have been identified as protonated caprolactam and a saturated 6-carbon primary amine, respectively. In the negative ion spectrum, methane sulfonic acid (MSA) has been identified as the parent species responsible for an ion commonly observed at mass 95 during these two studies. The diurnal variations of gas phase H{sub 2}SO{sub 4} and MSA were also measured at Cheeka Peak and have typically been found to be present in the sub-ppt range. Ion assisted measurements at Mauna Loa Observatory of pyridine and ammonia indicate concentrations of 2.5 and 70 ppt, respectively, with at least a factor of 2 uncertainty. Interesting variations and potential sources of several of the observed ions are also discussed.

  5. Fundamental mass transfer models for indoor air pollution sources

    SciTech Connect

    Tichenor, B.A.; Guo, Z.; Sparks, L.E.

    1993-01-01

    The paper discusses a simple, fundamental mass transfer model, based on Fick's Law of Diffusion, for indoor air pollution wet sorbent-based sources. (Note: Models are needed to predict emissions from indoor sources. While empirical approaches based on dynamic chamber data are useful, a more fundamental approach is needed to fully elucidate the relevant mass transfer processes). In the model, the mass transfer rate is assumed to be gas-phase limited and controlled by the boundary layer mass transfer coefficient, the saturation vapor pressure of the material being emitted, and the mass of volatile material remaining. Results of static and dynamic chamber tests, as well as test house studies, are presented.

  6. Proton/electron mass ratio and the electron`s atomic mass

    SciTech Connect

    Van Dyck, R.S. Jr.; Farnham, D.L.; Schwinberg, P.B.

    1994-12-31

    The heart of the Penning trap mass spectrometer (PTMS) is a well-machined, quadrupole trap with hyperbolic surfaces of revolution formed about a common axis of symmetry. Equally as important from the point of view of precision, a strong magnetic field, aligned along this trap axis, must be highly stable and uniform. For our present solenoid, the long term drift is {approx} 0.1-0.3 ppb/h and short-term fluctuations are < 1 ppb. This type of mass spectrometer has met with considerable success in measuring atomic masses with accuracies better than 1 ppb (and approaching a reliable 0.1 ppb). Thus, it is expected that this device can be used to improve the proton/electron mass ratio; however this task will be a significantly more difficult comparison because of the use of a trap potential of the opposite sign and widely differing magnitudes. The primary limitation in the past was the need for a magnetic bottle (i.e. a second-order term in the magnetic field on the order of 100 G/cm{sup 2}) in order to couple the magnetic states of the electron to the easily observed harmonic oscillation frequency along the axis of symmetry. In our previous determination of m{sub p}/m{sub e}, a systematic shift of {approx} -0.5 ppb/(G/cm{sup 2}) was observed which was believed to be due to the different {rvec E} x {rvec B} drift orbits (called magnetron) which are associated with the electron and its calibration ion. At that time, an uncertainty of 40 G/cm{sup 2} in the actual magnetic bottle led to a 20 ppb uncertainty in m{sub p}/m{sub e}. Our present efforts axe now using a quite uniform magnetic field (with B{sub 2} < 2 G/cm{sub 2}).

  7. Aerosol chemical components in Alaska air masses: 1. Aged pollution

    NASA Astrophysics Data System (ADS)

    Shaw, Glenn E.

    1991-12-01

    A 4-year Alaska chemical data set of aerosols or "dust" in the air clearly reveals a mixture of distinct aerosol components with different and interesting chemical composition, one or two being ascribed to pollution imported to Alaska by winds all the way from other continents. Of particular note is a strong chemical contrast between what we imagine to be highly scavenged, orographically lifted, northern Pacific air (Pacific marine air mass) and stagnant Arctic air (polar air mass), the latter containing seasonal average concentrations of between 2-4 times the concentration of the former, at least for pollution markers noncrustal vanadium, noncrustal manganese, arsenic, selenium, bromine, and antimony. The findings concur our old discovery that Arctic air is persistently polluted (Arctic haze), but Pacific air is relatively clean, in spite of the fact that Alaska is downwind of major pollution sources in the Orient. This is remarkable. In this the first of a two-part paper, we concentrate on the pollution component found primarily during incursion of Arctic polar air. Two major occurrences of visual haze with optical depths of approximately 0.2 and elevated aerosol concentration lasting about a month (spring 1985 and 1986) were affiliated with strong incoming transport of polar air, temperatures ranging from 10° to 20°C below normal (polar air) and air trajectory hindcasts leading back to industrial pollution sources in Eurasia. These long-range transport pollution events brought metal-rich aerosol of removal-resistant submicron particles. The size, chemistry, and meteorology all strongly suggest the presence of a well-aged (10-100 day) polluted air mass. An important implication is that in spring a large fraction of the Arctic polar air mass becomes charged with by-products of industrial pollution. In this multiyear chemical data set one finds a notable summer-winter contrast, changing by factors of 2 to 4 for pollution markers As, Se, Sb, and noncrustal

  8. Multi-collector Isotope Ratio Mass Spectrometer -- Operational Performance Report

    SciTech Connect

    Appelhans, Anthony D; Olson, John E; Watrous, Matthew G; Ward, Michael B.; Dahl, David A.

    2010-12-01

    This report describes the operational testing of a new magnetic sector mass spectrometer that utilizes seven full-sized discrete dynode electron multipliers operating simultaneously. The instrument includes a newly developed ion dispersion lens that enables the mass dispersed individual isotope beams to be separated sufficiently to allow a full-sized discrete dynode pulse counting multiplier to be used to measure each isotope beam. The performance of the instrument was measured using SRM 996 (244Pu spike) at loadings of 2.4 and 12 fg on resin beads and with SRM 4350B Columbia River Sediment samples. The measured limit of detection (3s) for 240Pu was 3.4 attograms for SRM 996. The limit of quantitation (LOQ), defined as 10 s, was 11.2 attograms. The measured concentration of 239Pu in the CRS standard was 152 ± 6 fg/g.

  9. Seven Channel Multi-collector Isotope Ratio Mass Spectrometer

    SciTech Connect

    Anthony D. Appelhans

    2008-07-01

    A new magnetic sector mass spectrometer that utilizes seven full-sized discrete dynode electron multipliers operating simultaneously has been designed, constructed and is in preliminary testing. The instrument utilizes a newly developed ion dispersion lens that enables the mass dispersed individual isotope beams to be separated sufficiently (35 mm) to allow a full-sized discrete dynode pulse counting multiplier to be used for each beam. The ion dispersion lens is a two element electrostatic 90 degree sector device that causes the beam-to-beam dispersion to increase faster than the intra-beam dispersion. Each multiplier is contained in an isolated case with a deflector/condenser lens at the entrance. A 9-sample filament cartridge is mounted on a micro-manipulator two-axis stage that enables adjustment of the filament position with 10 micron resolution within the ion lens. Results of initial testing with actinides will be presented.

  10. On the uncertainties of photon mass energy-absorption coefficients and their ratios for radiation dosimetry

    NASA Astrophysics Data System (ADS)

    Andreo, Pedro; Burns, David T.; Salvat, Francesc

    2012-04-01

    A systematic analysis of the available data has been carried out for mass energy-absorption coefficients and their ratios for air, graphite and water for photon energies between 1 keV and 2 MeV, using representative kilovoltage x-ray spectra for mammography and diagnostic radiology below 100 kV, and for 192Ir and 60Co gamma-ray spectra. The aim of this work was to establish ‘an envelope of uncertainty’ based on the spread of the available data. Type A uncertainties were determined from the results of Monte Carlo (MC) calculations with the PENELOPE and EGSnrc systems, yielding mean values for µen/ρ with a given statistical standard uncertainty. Type B estimates were based on two groupings. The first grouping consisted of MC calculations based on a similar implementation but using different data and/or approximations. The second grouping was formed by various datasets, obtained by different authors or methods using the same or different basic data, and with different implementations (analytical, MC-based, or a combination of the two); these datasets were the compilations of NIST, Hubbell, Johns-Cunningham, Attix and Higgins, plus MC calculations with PENELOPE and EGSnrc. The combined standard uncertainty, uc, for the µen/ρ values for the mammography x-ray spectra is 2.5%, decreasing gradually to 1.6% for kilovoltage x-ray spectra up to 100 kV. For 60Co and 192Ir, uc is approximately 0.1%. The Type B uncertainty analysis for the ratios of µen/ρ values includes four methods of analysis and concludes that for the present data the assumption that the data interval represents 95% confidence limits is a good compromise. For the mammography x-ray spectra, the combined standard uncertainties of (µen/ρ)graphite,air and (µen/ρ)graphite,water are 1.5%, and 0.5% for (µen/ρ)water,air, decreasing gradually down to uc = 0.1% for the three µen/ρ ratios for the gamma-ray spectra. The present estimates are shown to coincide well with those of Hubbell (1977 Rad. Res

  11. Development of a local continuous sampling probe for the equivalence air-fuel ratio measurement. Application to spark ignition engine

    NASA Astrophysics Data System (ADS)

    Guibert, P.; Dicocco, E.

    This paper is a contribution to the development of an original technique for measuring the in-cylinder equivalence air-fuel ratio. The main objective was to construct an instrument able to furnish instantaneous values of hydrocarbon concentration for many consecutive cycles at a definite location, especially at the spark plug location. The probe is based on a hot-wire-like apparatus, but involves catalytic oxidation on the wire surface in order to be sensitive to the hydrocarbon concentration. In this paper, we present the different steps needed to develop and validate the probe. The first step focuses on the geometric configuration to simplify as much as possible the mass transfer phenomena on the wire. The second step is a parametric study to evaluate the sensitivity, confidence and lifetime of the wire. By physical analysis, we propose a relationship between the electrical signal and the air-fuel equivalence ratio of the sampled gases. The third step is the application of the probe to in-cylinder motored engine measurements, which confirms the ability of the technique to characterise, quantitatively, the homogeneity of the air-fuel mixture, especially during the compression stroke. This work points out that the global sensitivity is estimated at 4V per unit of equivalence air-fuel ratio and the response time is estimated at about 400μs. The equivalence air-fuel ratio range is from pure air to 1.2. Experiments show that it is necessary to calibrate the system before use because of the existence of multiple catalysis states. The probe presents advantages associated with its simplicity, its low cost and its direct engine application without any modifications.

  12. Reduction of determinate errors in mass bias-corrected isotope ratios measured using a multi-collector plasma mass spectrometer

    NASA Astrophysics Data System (ADS)

    Doherty, W.

    2015-05-01

    A nebulizer-centric instrument response function model of the plasma mass spectrometer was combined with a signal drift model, and the result was used to identify the causes of the non-spectroscopic determinate errors remaining in mass bias-corrected Pb isotope ratios (Tl as internal standard) measured using a multi-collector plasma mass spectrometer. Model calculations, confirmed by measurement, show that the detectable time-dependent errors are a result of the combined effect of signal drift and differences in the coordinates of the Pb and Tl response function maxima (horizontal offset effect). If there are no horizontal offsets, then the mass bias-corrected isotope ratios are approximately constant in time. In the absence of signal drift, the response surface curvature and horizontal offset effects are responsible for proportional errors in the mass bias-corrected isotope ratios. The proportional errors will be different for different analyte isotope ratios and different at every instrument operating point. Consequently, mass bias coefficients calculated using different isotope ratios are not necessarily equal. The error analysis based on the combined model provides strong justification for recommending a three step correction procedure (mass bias correction, drift correction and a proportional error correction, in that order) for isotope ratio measurements using a multi-collector plasma mass spectrometer.

  13. Comment on "Improved ray tracing air mass numbers model"

    NASA Astrophysics Data System (ADS)

    van der Werf, Siebren Y.

    2008-01-01

    Air mass numbers have traditionally been obtained by techniques that use height as the integration variable. This introduces an inherent singularity at the horizon, and ad hoc solutions have been invented to cope with it. A survey of the possible options including integration by height, zenith angle, and horizontal distance or path length is presented. Ray tracing by path length is shown to avoid singularities both at the horizon and in the zenith. A fourth-order Runge-Kutta numerical integration scheme is presented, which treats refraction and air mass as path integrals. The latter may optionally be split out into separate contributions of the atmosphere's constituents.

  14. Measurement of the stable carbon isotope ratio of atmospheric volatile organic compounds using chromatography, combustion, and isotope ratio mass spectrometry coupled with thermal desorption

    NASA Astrophysics Data System (ADS)

    Kawashima, Hiroto; Murakami, Mai

    2014-06-01

    The isotopic analysis of atmospheric volatile organic compounds (VOCs), and in particular of their stable carbon isotope ratio (δ13C), could potentially be used as an effective tool for identifying the sources of VOCs. However, to date, there have been very few such analyses. In this work, we analyze the δ13C values of VOCs using thermal desorption coupled with chromatography, combustion, and isotope ratio mass spectrometry (TD-GC/C/IRMS). The measured peak shapes were of high quality and 36 compounds in a standard gas containing 58 VOCs (C5-C11) were detected. The measured δ13C varied widely, from -49.7‰ to -22.9‰, while the standard deviation of the δ13C values varied from 0.07‰ to 0.85‰ (n = 5). We then measured samples from two passenger cars in hot and cold modes, three gas stations, roadside air, and ambient air. In comparison with existing studies, the analytical precision for the 36 compounds in this study was reasonable. By comparing the δ13C values obtained from the cars and gas stations, we could identify some degree of the sources of VOCs in the roadside and ambient air samples.

  15. Warm-air advection, air mass transformation and fog causes rapid ice melt

    NASA Astrophysics Data System (ADS)

    Tjernström, Michael; Shupe, Matthew D.; Brooks, Ian M.; Persson, P. Ola G.; Prytherch, John; Salisbury, Dominic J.; Sedlar, Joseph; Achtert, Peggy; Brooks, Barbara J.; Johnston, Paul E.; Sotiropoulou, Georgia; Wolfe, Dan

    2015-07-01

    Direct observations during intense warm-air advection over the East Siberian Sea reveal a period of rapid sea-ice melt. A semistationary, high-pressure system north of the Bering Strait forced northward advection of warm, moist air from the continent. Air-mass transformation over melting sea ice formed a strong, surface-based temperature inversion in which dense fog formed. This induced a positive net longwave radiation at the surface while reducing net solar radiation only marginally; the inversion also resulted in downward turbulent heat flux. The sum of these processes enhanced the surface energy flux by an average of ~15 W m-2 for a week. Satellite images before and after the episode show sea-ice concentrations decreasing from > 90% to ~50% over a large area affected by the air-mass transformation. We argue that this rapid melt was triggered by the increased heat flux from the atmosphere due to the warm-air advection.

  16. Chemiluminescence-based multivariate sensing of local equivalence ratios in premixed atmospheric methane-air flames

    SciTech Connect

    Tripathi, Markandey M.; Krishnan, Sundar R.; Srinivasan, Kalyan K.; Yueh, Fang-Yu; Singh, Jagdish P.

    2011-09-07

    Chemiluminescence emissions from OH*, CH*, C2, and CO2 formed within the reaction zone of premixed flames depend upon the fuel-air equivalence ratio in the burning mixture. In the present paper, a new partial least square regression (PLS-R) based multivariate sensing methodology is investigated and compared with an OH*/CH* intensity ratio-based calibration model for sensing equivalence ratio in atmospheric methane-air premixed flames. Five replications of spectral data at nine different equivalence ratios ranging from 0.73 to 1.48 were used in the calibration of both models. During model development, the PLS-R model was initially validated with the calibration data set using the leave-one-out cross validation technique. Since the PLS-R model used the entire raw spectral intensities, it did not need the nonlinear background subtraction of CO2 emission that is required for typical OH*/CH* intensity ratio calibrations. An unbiased spectral data set (not used in the PLS-R model development), for 28 different equivalence ratio conditions ranging from 0.71 to 1.67, was used to predict equivalence ratios using the PLS-R and the intensity ratio calibration models. It was found that the equivalence ratios predicted with the PLS-R based multivariate calibration model matched the experimentally measured equivalence ratios within 7%; whereas, the OH*/CH* intensity ratio calibration grossly underpredicted equivalence ratios in comparison to measured equivalence ratios, especially under rich conditions ( > 1.2). The practical implications of the chemiluminescence-based multivariate equivalence ratio sensing methodology are also discussed.

  17. Isolation and identification of pathogenic microorganisms at wastewater-irrigated fields: ratios in air and wastewater

    SciTech Connect

    Teltsch, B.; Kedmi, S.; Bonnet, L.; Borenzstajn-Rotem, Y.; Katzenelson, E.

    1980-06-01

    Samples of air and corresponding wastewater samples were taken at wastewater spray-irrigated fields. The concentrations of salmonellae and enteroviruses present in these samples were determined and compared with those of coliforms, and the ratios between them were calculated. The most common Salmonella serotype in the air was Salmonella ohio, whereas in the wastewater, Salmonella anatum was the most common. Enteroviruses isolated and identified were poliovirus, echovirus, and coxsackievirus type B. From the ratios of salmonellas to coliforms and enteroviruses to coliforms in the air, as compared to these ratios in the wastewater, it was concluded that the suitability of coliforms as an indication of airborne contamination caused by spray irrigation is questionable.

  18. FUNDAMENTAL MASS TRANSFER MODELS FOR INDOOR AIR POLLUTION SOURCES

    EPA Science Inventory

    The paper discusses a simple, fundamental mass transfer model, based on Fick's Law of Diffusion, for indoor air pollution wet sorbent-based sources. (Note: Models are needed to predict emissions from indoor sources. hile empirical approaches based on dynamic chamber data are usef...

  19. Microlensing discovery of a tight, low-mass-ratio planetary-mass object around an old field brown dwarf

    SciTech Connect

    Han, C.; Jung, Y. K.; Udalski, A.; Szymański, M. K.; Kubiak, M.; Pietrzyński, G.; Soszyński, I.; Skowron, J.; Kozłowski, S.; Poleski, R.; Ulaczyk, K.; Wyrzykowski, Ł.; Pietrukowicz, P.; Sumi, T.; Gaudi, B. S.; Gould, A.; Bennett, D. P.; Tsapras, Y.; Abe, F.; Bond, I. A.; Collaboration: OGLE Collaboration; MOA Collaboration; μFUN Collaboration; RoboNet Collaboration; and others

    2013-11-20

    Observations of accretion disks around young brown dwarfs (BDs) have led to the speculation that they may form planetary systems similar to normal stars. While there have been several detections of planetary-mass objects around BDs (2MASS 1207-3932 and 2MASS 0441-2301), these companions have relatively large mass ratios and projected separations, suggesting that they formed in a manner analogous to stellar binaries. We present the discovery of a planetary-mass object orbiting a field BD via gravitational microlensing, OGLE-2012-BLG-0358Lb. The system is a low secondary/primary mass ratio (0.080 ± 0.001), relatively tightly separated (∼0.87 AU) binary composed of a planetary-mass object with 1.9 ± 0.2 Jupiter masses orbiting a BD with a mass 0.022 M {sub ☉}. The relatively small mass ratio and separation suggest that the companion may have formed in a protoplanetary disk around the BD host in a manner analogous to planets.

  20. The Measurement of Fuel-Air Ratio by Analysis for the Oxidized Exhaust Gas

    NASA Technical Reports Server (NTRS)

    Gerrish, Harold C.; Meem, J. Lawrence, Jr.

    1943-01-01

    An investigation was made to determine a method of measuring fuel-air ratio that could be used for test purposes in flight and for checking conventional equipment in the laboratory. Two single-cylinder test engines equipped with typical commercial engine cylinders were used. The fuel-air ratio of the mixture delivered to the engines was determined by direct measurement of the quantity of air and of fuel supplied and also by analysis of the oxidized exhaust gas and of the normal exhaust gas. Five fuels were used: gasoline that complied with Army-Navy fuel Specification No. AN-VV-F-781 and four mixtures of this gasoline with toluene, benzene, and xylene. The method of determining the fuel-air ratio described in this report involves the measurement of the carbon-dioxide content of the oxidized exhaust gas and the use of graphs for the presented equation. This method is considered useful in aircraft, in the field, or in the laboratory for a range of fuel-air ratios from 0.047 to 0.124.

  1. The Measurement of Fuel-air Ratio by Analysis of the Oxidized Exhaust Gas

    NASA Technical Reports Server (NTRS)

    Memm, J. Lawrence, Jr.

    1943-01-01

    An investigation was made to determine a method of measuring fuel-air ratio that could be used for test purposes in flight and for checking conventional equipment in the laboratory. Two single-cylinder test engines equipped with typical commercial engine cylinders were used. The fuel-air ratio of the mixture delivered to the engines was determined by direct measurement of the quantity of air and of fuel supplied and also by analysis of the oxidized exhaust gas and of the normal exhaust gas. Five fuels were used: gasoline that complied with Army-Navy Fuel Specification, No. AN-VV-F-781 and four mixtures of this gasoline with toluene, benzene, and xylene. The method of determining the fuel-air ratio described in this report involves the measurement of the carbon-dioxide content of the oxidized exhaust gas and the use of graphs or the presented equation. This method is considered useful in aircraft, in the field, or in the laboratory for a range of fuel-air ratios from 0.047 to 0.124

  2. Enhancement of acidic gases in biomass burning impacted air masses over Canada

    NASA Technical Reports Server (NTRS)

    Lefer, B. L.; Talbot, R. W.; Harriss, R. C.; Bradshaw, J. D.; Sandholm, S. T.; Olson, J. O.; Sachse, G. W.; Collins, J.; Shipham, M. A.; Blake, D. R.

    1994-01-01

    Biomass-burning impacted air masses sampled over central and eastern Canada during the summer of 1990 as part of ABLE 3B contained enhanced mixing ratios of gaseous HNO3, HCOOH, CH3COOH, and what appears to be (COOH)2. These aircraft-based samples were collected from a variety of fresh burning plumes and more aged haze layers from different source regions. Values of the enhancement factor, delta X/delta CO, where X represents an acidic gas, for combustion-impacted air masses sampled both near and farther away from the fires, were relatively uniform. However, comparison of carboxylic acid emission ratios measured in laboratory fires to field plume enhancement factors indicates significant in-plume production of HCOOH. Biomass-burning appears to be an important source of HNO3, HCOOH, and CH3COOH to the troposphere over subarctic Canada.

  3. Study of single and combined mass-sensitive observables of cosmic ray induced extensive air showers

    NASA Astrophysics Data System (ADS)

    Rastegarzadeh, G.; Nemati, M.

    2016-03-01

    In this study, combinations of the global arrival time, (Δτ_{global}), pseudorapidity, and lateral density distribution (ρ_{μ}) of muons, which are three mass-sensitive observables of cosmic ray induced extensive air showers, have been used as new parameters to study the primary mass discrimination around the knee energies (100 TeV-10 PeV). This is a simulation-based study and the simulations have been performed for the KASCADE array at Karlsruhe and the Alborz-I array at Tehran to study the effect of the altitude on the quality of the primary mass discrimination. The merit factors of the single and combined three mass-sensitive observables have been calculated to compare the discrimination power of combined and single observables. We have used the CORSIKA 7.4 code to simulate the extensive air showers (EASs) sample sets. Considering all aspects of our study, it is found that the ratio of the global time to the lateral density distribution of the muons gives better results than other ratios; also in the case of single observables, the muon density gives better results compared with the other observables. Also it is shown that below 1 PeV primary energies, the ratio of the muon global time to the muon density (Δτ_{global}/ρ_{μ}) results in a better mass discrimination relative to the muon density only.

  4. CCD Photometry of Low Mass Ratio Contact Binary FP Boo - IV

    NASA Astrophysics Data System (ADS)

    Oh, Kyu-Dong; Lee, Woo-Baik

    2009-03-01

    We present new B, V, and R CCD photometric light curves for the low mass ratio contact binay FP Boo. A new photometric solution and absolute physical dimensions of the system were derived by applying the Wilson-Devinney program to our observed light curves and to previously published Rucinski et al.'s radial velocity curves. From the H-R diagram of 24 low mass ratio contact binary system including FP Boo, the evolutionary stage of FP Boo was found to coincide with those of the general low mass ratio contact binary systems. The light curves obtained in this season show a small asymmetry in their shapes.

  5. Elemental ratio measurements of organic compounds using aerosol mass spectrometry: characterization, improved calibration, and implications

    DOE PAGESBeta

    Canagaratna, M. R.; Jimenez, J. L.; Kroll, J. H.; Chen, Q.; Kessler, S. H.; Massoli, P.; Hildebrandt Ruiz, L.; Fortner, E.; Williams, L. R.; Wilson, K. R.; et al

    2015-01-12

    Elemental compositions of organic aerosol (OA) particles provide useful constraints on OA sources, chemical evolution, and effects. The Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) is widely used to measure OA elemental composition. This study evaluates AMS measurements of atomic oxygen-to-carbon (O : C), hydrogen-to-carbon (H : C), and organic mass-to-organic carbon (OM : OC) ratios, and of carbon oxidation state (OS C) for a vastly expanded laboratory data set of multifunctional oxidized OA standards. For the expanded standard data set, the method introduced by Aiken et al. (2008), which uses experimentally measured ion intensities at all ions to determinemore » elemental ratios (referred to here as "Aiken-Explicit"), reproduces known O : C and H : C ratio values within 20% (average absolute value of relative errors) and 12%, respectively. The more commonly used method, which uses empirically estimated H2O+ and CO+ ion intensities to avoid gas phase air interferences at these ions (referred to here as "Aiken-Ambient"), reproduces O : C and H : C of multifunctional oxidized species within 28 and 14% of known values. The values from the latter method are systematically biased low, however, with larger biases observed for alcohols and simple diacids. A detailed examination of the H2O+, CO+, and CO2+ fragments in the high-resolution mass spectra of the standard compounds indicates that the Aiken-Ambient method underestimates the CO+ and especially H2O+ produced from many oxidized species. Combined AMS–vacuum ultraviolet (VUV) ionization measurements indicate that these ions are produced by dehydration and decarboxylation on the AMS vaporizer (usually operated at 600 °C). Thermal decomposition is observed to be efficient at vaporizer temperatures down to 200 °C. These results are used together to develop an "Improved-Ambient" elemental analysis method for AMS spectra measured in air. The Improved-Ambient method uses specific ion

  6. Interaction of mid-latitude air masses with the polar dome area during RACEPAC and NETCARE

    NASA Astrophysics Data System (ADS)

    Bozem, Heiko; Hoor, Peter; Koellner, Franziska; Kunkel, Daniel; Schneider, Johannes; Schulz, Christiane; Herber, Andreas; Borrmann, Stephan; Wendisch, Manfred; Ehrlich, Andre; Leaitch, Richard; Willis, Megan; Burkart, Julia; Thomas, Jennie; Abbatt, Jon

    2016-04-01

    We present aircraft based trace gas measurements in the Arctic during RACEPAC (2014) and NETCARE (2014 and 2015) with the Polar 6 aircraft of Alfred Wegener Institute (AWI) covering an area from 134°W to 17°W and 68°N to 83°N. We focus on cloud, aerosol and general transport processes of polluted air masses into the high Arctic. Based on CO and CO2 measurements and kinematic 10-day back trajectories as well as Flexpart particle dispersion modeling we analyze the transport regimes of mid-latitude air masses traveling to the high Arctic prevalent during spring (RACEPAC 2014, NETCARE 2015) and summer (NETCARE 2014). In general more northern parts of the high Arctic (Lat > 75°N) were relatively unaffected from mid-latitude air masses. In contrast, regions further south are influenced by air masses from Asia and Russia (eastern part of Canadian Arctic and European Arctic) as well as from North America (central and western parts of Canadian Arctic). The transition between the mostly isolated high Arctic and more southern regions indicated by tracer gradients is remarkably sharp. This allows for a chemical definition of the Polar dome based on the variability of CO and CO2 as a marker. Isentropic surfaces that slope from the surface to higher altitudes in the high Arctic form the polar dome that represents a transport barrier for mid-latitude air masses to enter the lower troposphere in the high Arctic. Synoptic-scale weather systems frequently disturb this transport barrier and foster the exchange between air masses from the mid-latitudes and polar regions. This can finally lead to enhanced pollution levels in the lower polar troposphere. Mid-latitude pollution plumes from biomass burning or flaring entering the polar dome area lead to an enhancement of 30% of the observed CO mixing ratio within the polar dome area.

  7. Advancement and application of gas chromatography isotope ratio mass spectrometry techniques for atmospheric trace gas analysis

    NASA Astrophysics Data System (ADS)

    Giebel, Brian M.

    2011-12-01

    The use of gas chromatography isotope ratio mass spectrometry (GC-IRMS) for compound specific stable isotope analysis is an underutilized technique because of the complexity of the instrumentation and high analytical costs. However stable isotopic data, when coupled with concentration measurements, can provide additional information on a compounds production, transformation, loss, and cycling within the biosphere and atmosphere. A GC-IRMS system was developed to accurately and precisely measure delta13C values for numerous oxygenated volatile organic compounds having natural and anthropogenic sources. The OVOCs include methanol, ethanol, acetone, methyl ethyl ketone, 2-pentanone, and 3-pentanone. Guided by the requirements for analysis of trace components in air, the GC-IRMS system was developed with the goals of increasing sensitivity, reducing dead-volume and peak band broadening, optimizing combustion and water removal, and decreasing the split ratio to the IRMS. The technique relied on a two-stage preconcentration system, a low-volume capillary reactor and water trap, and a balanced reference gas delivery system. Measurements were performed on samples collected from two distinct sources (i.e. biogenic and vehicle emissions) and ambient air collected from downtown Miami and Everglades National Park. However, the instrumentation and the method have the capability to analyze a variety of source and ambient samples. The measured isotopic signatures that were obtained from source and ambient samples provide a new isotopic constraint for atmospheric chemists and can serve as a new way to evaluate their models and budgets for many OVOCs. In almost all cases, OVOCs emitted from fuel combustion were enriched in 13C when compared to the natural emissions of plants. This was particularly true for ethanol gas emitted in vehicle exhaust, which was observed to have a uniquely enriched isotopic signature that was attributed to ethanol's corn origin and use as an alternative

  8. Dusty air masses transport between Amazon Basin and Caribbean Islands

    NASA Astrophysics Data System (ADS)

    Euphrasie-Clotilde, Lovely; Molinie, Jack; Prospero, Joseph; Feuillard, Tony; Brute, Francenor; Jeannot, Alexis

    2015-04-01

    Depend on the month, African desert dust affect different parts of the North Atlantic Ocean. From December to April, Saharan dust outbreaks are often reported over the amazon basin and from May to November over the Caribbean islands and the southern regions of USA. This annual oscillation of Saharan dust presence, related to the ITCZ position, is perturbed some time, during March. Indeed, over Guadeloupe, the air quality network observed between 2007 and 2012 several dust events during March. In this paper, using HISPLIT back trajectories, we analyzed air masses trajectories for March dust events observed in Guadeloupe, from 2007 to 2012.We observed that the high pressure positions over the Atlantic Ocean allow the transport of dusty air masses from southern region of West Africa to the Caribbean Sea with a path crossing close to coastal region of French Guyana. Complementary investigations including the relationship between PM10 concentrations recorded in two sites Pointe-a-Pitre in the Caribbean, and Cayenne in French Guyana, have been done. Moreover we focus on the mean delay observed between the times arrival. All the results show a link between pathway of dusty air masses present over amazon basin and over the Caribbean region during several event of March. The next step will be the comparison of mineral dust composition for this particular month.

  9. Anomalous pressure dependence of thermal conductivities of large mass ratio compounds

    DOE PAGESBeta

    Lindsay, Lucas R; Broido, David A.; Carrete, Jesus; Mingo, Natalio; Reinecke, Tom L.

    2015-03-27

    The lattice thermal conductivities (k) of binary compound materials are examined as a function of hydrostatic pressure P using a first-principles approach. Compound materials with relatively small mass ratios, such as MgO, show an increase in k with P, consistent with measurements. Conversely, compounds with large mass ratios (e.g., BSb, BAs, BeTe, BeSe) exhibit decreasing with increasing P, a behavior that cannot be understood using simple theories of k. This anomalous P dependence of k arises from the fundamentally different nature of the intrinsic scattering processes for heat-carrying acoustic phonons in large mass ratio compounds compared to those with smallmore » mass ratios. We find this work demonstrates the power of first principles methods for thermal properties and advances the understanding of thermal transport in non-metals.« less

  10. Anomalous pressure dependence of thermal conductivities of large mass ratio compounds

    SciTech Connect

    Lindsay, Lucas R; Broido, David A.; Carrete, Jesus; Mingo, Natalio; Reinecke, Tom L.

    2015-03-27

    The lattice thermal conductivities (k) of binary compound materials are examined as a function of hydrostatic pressure P using a first-principles approach. Compound materials with relatively small mass ratios, such as MgO, show an increase in k with P, consistent with measurements. Conversely, compounds with large mass ratios (e.g., BSb, BAs, BeTe, BeSe) exhibit decreasing with increasing P, a behavior that cannot be understood using simple theories of k. This anomalous P dependence of k arises from the fundamentally different nature of the intrinsic scattering processes for heat-carrying acoustic phonons in large mass ratio compounds compared to those with small mass ratios. We find this work demonstrates the power of first principles methods for thermal properties and advances the understanding of thermal transport in non-metals.

  11. Summary report on effects at temperature, humidity, and fuel-air ratio on two air-cooled light aircraft engines

    NASA Technical Reports Server (NTRS)

    Kempke, E. E., Jr.

    1976-01-01

    Five different engine models were tested to experimentally characterize emissions and to determine the effects of variation in fuel-air ratio and spark timing on emissions levels and other operating characteristics such as cooling, misfiring, roughness, power acceleration, etc. The results are given of two NASA reports covering the Avco Lycoming 0-320-D engine testing and the recently obtained results on the Teledyne Continental TSIO-360-C engine.

  12. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT, MIRATECH CORPORATIONM GECO 3001 AIR/FUEL RATIO CONTROLLER

    EPA Science Inventory

    Details on the verification test design, measurement test procedures, and Quality assurance/Quality Control (QA/QC) procedures can be found in the test plan titled Testing and Quality Assurance Plan, MIRATECH Corporation GECO 3100 Air/Fuel Ratio Controller (SRI 2001). It can be d...

  13. HOME AIR NICOTINE LEVELS AND URINE COTININE-CREATININE RATIOS IN PRESCHOOL CHILDREN

    EPA Science Inventory

    We studied urine cotinine excretion in 27 children who attended a research day care center to determine the extent of correlation between urine cotinine-creatinine ratios (CCR) and intensity of nicotine exposure in the home. verage nicotine levels in home air were determined by a...

  14. Carbon isotope ratio analysis of steroids by high-temperature liquid chromatography-isotope ratio mass spectrometry.

    PubMed

    Zhang, Lijun; Thevis, Mario; Piper, Thomas; Jochmann, Maik A; Wolbert, J Benjamin; Kujawinski, Dorothea M; Wiese, Steffen; Teutenberg, Thorsten; Schmidt, Torsten C

    2014-03-01

    Generally, compound-specific isotope analysis of steroids is carried out by gas chromatography combined with isotope ratio mass spectrometry. Thus, a derivatization of the steroids prior to the measurement is compulsory, and a correction of the isotopic data is often necessary. To overcome this limitation, we present a new approach of high-temperature liquid chromatography coupled with photodiode array detection and isotope ratio mass spectrometry (HT-LC/PDA/IRMS) for the carbon isotope ratio analysis of unconjugated steroids. A steroid mixture containing 19-norandrosterone, testosterone, epitestosterone, androsterone, and 5β-pregnane-3α,17α,20α-triol was fully separated on a C4 column under high-temperature elution with water as the sole eluent. The accuracy for isotope analysis (±0.5 ‰) was around 20 μg g(-1) for testosterone, epitestosterone (79 ng steroid absolute on column), and 30 μg g(-1) for 19-norandrosterone, androsterone, and 5β-pregnane-3α,17α,20α-triol (119 ng steroid absolute on column). The applicability of the method was tested by measuring a pharmaceutical gel containing testosterone. With this work, the scope of LC/IRMS applications has been extended to nonpolar compounds. PMID:24491121

  15. Monte Carlo simulations on the water-to-air stopping power ratio for carbon ion dosimetry

    SciTech Connect

    Henkner, Katrin; Bassler, Niels; Sobolevsky, Nikolai; Jaekel, Oliver

    2009-04-15

    Many papers discussed the I value for water given by the ICRU, concluding that a value of about 80{+-}2 eV instead of 67.2 eV would reproduce measured ion depth-dose curves. A change in the I value for water would have an effect on the stopping power and, hence, on the water-to-air stopping power ratio, which is important in clinical dosimetry of proton and ion beams. For energies ranging from 50 to 330 MeV/u and for one spread out Bragg peak, the authors compare the impact of the I value on the water-to-air stopping power ratio. The authors calculate ratios from different ICRU stopping power tables and ICRU reports. The stopping power ratio is calculated via track-length dose calculation with SHIELD-HIT07. In the calculations, the stopping power ratio is reduced to a value of 1.119 in the plateau region as compared to the cited value of 1.13 in IAEA TRS-398. At low energies the stopping power ratio increases by up to 6% in the last few tenths of a mm toward the Bragg peak. For a spread out Bragg peak of 13.5 mm width at 130 mm depth, the stopping power ratio increases by about 1% toward the distal end.

  16. Fidelity of reduced and realistic electron mass ratio multi-scale gyrokinetic simulations of tokamak discharges

    NASA Astrophysics Data System (ADS)

    Howard, N. T.; Holland, C.; White, A. E.; Greenwald, M.; Candy, J.

    2015-06-01

    The first study using multi-scale (coupled ITG/TEM/ETG) gyrokinetic simulations at both reduced and realistic electron mass ratios, μ = (mD/me).5 = 20.0, 40.0 and 60.0, has been performed on a standard, Alcator C-Mod, L-mode discharge. Ion-scale (kθρs  ∼  1.0) and multi-scale (up to kθρe  ∼  0.8) gyrokinetic simulations are compared at different simulated mass ratios to investigate the fidelity of reduced electron mass ratio, multi-scale simulation through direct comparison with realistic mass ratio, multi-scale simulation. Detailed description of both the numerical setup and the turbulent scales required to obtain meaningful coupled ITG/TEM/ETG simulation is presented. Significant high-k driven (TEM/ETG) heat flux is found to exist at scales of approximately kθρe  ∼  0.1 at all mass ratios but can only be obtained by simulation capturing turbulence up to kθρe  ∼  1.0. At slightly reduced mass ratio, μ = 40.0, qualitative agreement with realistic mass simulation can be obtained in the studied discharge, consistent with intuition obtained from linear stability analysis. However, realistic electron mass is required for any robust quantitative comparison with experimental heat fluxes for the condition studied, as significant differences are observed at even slightly reduced electron mass ratio. The details of this numerical study are presented to provide a basis for future studies utilizing coupled ITG/TEM/ETG gyrokinetic simulation.

  17. Swirl-can combustor performance to near-stoichiometric fuel-air ratio

    NASA Technical Reports Server (NTRS)

    Diehl, L. A.; Biaglow, J. A.

    1976-01-01

    Emissions and performance characteristics were determined for full-annulus swirl-can modular combustors operated to near stoichiometric fuel air ratios. The purposes of the tests were to obtain stoichiometric data at inlet air temperatures up to 894 K and to determine the effect of module number by investigating 120 and 72 module swirl-can combustors. The maximum average exit temperature obtained with the 120-module swirl-can combustor was 2465 K with a combustion efficiency of 95 percent at an inlet-air temperature of 894 K. The 72-module swirl-can combustor reached a maximum average exit temperature of 2306 K with a combustion efficiency of 92 percent at an inlet air temperature of 894 K. At a constant inlet air temperature, maximum oxides of nitrogen emission index values occurred at a fuel-air ratio of 0.037 for the 72-module design and 0.044 for the 120-module design. The combustor average exit temperature and combustion efficiency were calculated from emissions measurements. The measured emissions included carbon monoxide, unburned hydrocarbons, oxides of nitrogen, and smoke.

  18. X-ray dual energy spectral parameter optimization for bone Calcium/Phosphorus mass ratio estimation

    NASA Astrophysics Data System (ADS)

    Sotiropoulou, P. I.; Fountos, G. P.; Martini, N. D.; Koukou, V. N.; Michail, C. M.; Valais, I. G.; Kandarakis, I. S.; Nikiforidis, G. C.

    2015-09-01

    Calcium (Ca) and Phosphorus (P) bone mass ratio has been identified as an important, yet underutilized, risk factor in osteoporosis diagnosis. The purpose of this simulation study is to investigate the use of effective or mean mass attenuation coefficient in Ca/P mass ratio estimation with the use of a dual-energy method. The investigation was based on the minimization of the accuracy of Ca/P ratio, with respect to the Coefficient of Variation of the ratio. Different set-ups were examined, based on the K-edge filtering technique and single X-ray exposure. The modified X-ray output was attenuated by various Ca/P mass ratios resulting in nine calibration points, while keeping constant the total bone thickness. The simulated data were obtained considering a photon counting energy discriminating detector. The standard deviation of the residuals was used to compare and evaluate the accuracy between the different dual energy set-ups. The optimum mass attenuation coefficient for the Ca/P mass ratio estimation was the effective coefficient in all the examined set-ups. The variation of the residuals between the different set-ups was not significant.

  19. Comparison of thermal ionization mass spectrometry and Multiple Collector Inductively Coupled Plasma Mass Spectrometry for cesium isotope ratio measurements

    NASA Astrophysics Data System (ADS)

    Isnard, H.; Granet, M.; Caussignac, C.; Ducarme, E.; Nonell, A.; Tran, B.; Chartier, F.

    2009-11-01

    In the nuclear domain, precise and accurate isotopic composition determination of elements in spent nuclear fuels is mandatory to validate neutron calculation codes and for nuclear waste disposal. The present study presents the results obtained on Cs isotope ratio by mass spectrometric measurements. Natural cesium is monoisotopic ( 133Cs) whereas cesium in spent fuels has 4 isotopes ( 133Cs, 134Cs, 135Cs, and 137Cs). As no standard reference material is available to evaluate the accuracy of Cs isotopic measurements, a comparison of cesium isotopic composition in spent nuclear fuels has been performed between Thermal Ionization Mass Spectrometry (TIMS) and a new method involving Multiple Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICPMS) measurements. For TIMS measurements, isotopic fractionation has been evaluated by studying the behavior of cesium isotope ratios ( 133Cs/ 137Cs and 135Cs/ 137Cs) during the analyses. For MC-ICPMS measurements, the mass bias effects have been corrected with an external mass bias correction using elements (Eu and Sb) close to cesium masses. The results obtained by the two techniques show good agreement: relative difference on 133Cs/ 137Cs and 135Cs/ 137Cs ratios for two nuclear samples, analyzed after chemical separation, ranges from 0.2% to 0.5% depending on the choice of reference value for mass bias correction by MC-ICPMS. Finally the quantification of the 135Cs/ 238U ratio by the isotope dilution technique is presented in the case of a MOx (mixed oxide) spent fuel sample. Evaluation of the global uncertainties shows that this ratio could be defined at an uncertainty of 0.5% ( k = 2). The intercomparison between two independent mass spectrometric techniques is fundamental for the evaluation of uncertainty when no isotopic standard is available.

  20. Adaptive RBF network for parameter estimation and stable air-fuel ratio control.

    PubMed

    Wang, Shiwei; Yu, D L

    2008-01-01

    In the application of variable structure control to engine air-fuel ratio, the ratio is subjected to chattering due to system uncertainty, such as unknown parameters or time varying dynamics. This paper proposes an adaptive neural network method to estimate two immeasurable physical parameters on-line and to compensate for the model uncertainty and engine time varying dynamics, so that the chattering is substantially reduced and the air-fuel ratio is regulated within the desired range of the stoichiometric value. The adaptive law of the neural network is derived using the Lyapunov method, so that the stability of the whole system and the convergence of the networks are guaranteed. Computer simulations based on a mean value engine model demonstrate the effectiveness of the technique. PMID:18166378

  1. Elemental ratio measurements of organic compounds using aerosol mass spectrometry: characterization, improved calibration, and implications

    DOE PAGESBeta

    Canagaratna, M. R.; Jimenez, J. L.; Kroll, J. H.; Chen, Q.; Kessler, S. H.; Massoli, P.; Hildebrandt Ruiz, L.; Fortner, E.; Williams, L. R.; Wilson, K. R.; et al

    2014-07-31

    Elemental compositions of organic aerosol (OA) particles provide useful constraints on OA sources, chemical evolution, and effects. The Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) is widely used to measure OA elemental composition. This study evaluates AMS measurements of atomic oxygen-to-carbon (O : C), hydrogen-to-carbon (H : C), organic mass-to-organic carbon (OM : OC), and carbon oxidation state (OSC) for a vastly expanded laboratory dataset of multifunctional oxidized OA standards. For the expanded standard dataset, the "Aiken-Explicit" method (Aiken et al., 2008), which uses experimentally measured ion intensities at all ions to determine elemental ratios, reproduces known molecular O :more » C and H : C ratio values within 20% (average absolute value of relative errors) and 12% respectively. The more commonly used "Aiken-Ambient" method, which uses empirically estimated H2O+ and CO+ ion intensities to avoid gas phase air interferences at these ions, reproduces O : C and H : C of multifunctional oxidized species within 28% and 14% of known values. These values are systematically biased low, however, with larger biases observed for alcohols and simple diacids. A detailed examination of the H2O+, CO+, and CO2+ fragments in the high-resolution mass spectra of the standard compounds indicates that the Aiken-Ambient method underestimates the CO+ and H2O+ produced from many oxidized species. Combined AMS-vacuum ultraviolet (VUV) ionization measurements indicate that these ions are produced by dehydration and decarboxylation on the AMS vaporizer (usually operated at 600 °C). Thermal decomposition is observed to be efficient at vaporizer temperatures down to 200 °C. These results are used together to develop an "Improved-Ambient" elemental analysis method for AMS spectra measured in air. The Improved-Ambient method reduces the systematic biases and reproduces O : C (H : C) ratios of individual oxidized standards within 28% (13

  2. Ratios of the molecular species of triacylglycerols in lesquerella (Physaria fendleri) oil estimated by mass spectrometry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ratios of regioisomers of 72 molecular species of triacylglycerols (TAG) in lesquerella oil were estimated using the electrospray ionization mass spectrometry of the lithium adducts of TAG in the HPLC fractions of lesquerella oil. The ratios of ion signal intensities (or relative abundances) of ...

  3. Ratios of the molecular species of triacylglycerols in lesquerella (Physaria fendleri) oil estimated by mass spectrometry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ratios of regioisomers of 74 molecular species of triacylglycerols (TAG) in lesquerella oil were estimated using HPLC and the electrospray ionization mass spectrometry of the lithium adducts of TAG in the HPLC fractions of lequerella oil. The ratios of relative abundances of the fragment ions fr...

  4. Carbon isotopic analysis of atmospheric methane by isotope-ratio-monitoring gas chromatography-mass spectrometry

    NASA Technical Reports Server (NTRS)

    Merritt, Dawn A.; Hayes, J. M.; Des Marais, David J.

    1995-01-01

    Less than 15 min are required for the determination of delta C(sub PDB)-13 with a precision of 0.2 ppt(1 sigma, single measurement) in 5-mL samples of air containing CH4 at natural levels (1.7 ppm). An analytical system including a sample-introduction unit incorporating a preparative gas chromatograph (GC) column for separation of CH4 from N2, O2, and Ar is described. The 15-min procedure includes time for operation of that system, high-resolution chromatographic separation of the CH4, on-line combustion and purification of the products, and isotopic calibration. Analyses of standards demonstrate that systematic errors are absent and that there is no dependence of observed values of delta on sample size. For samples containing 100 ppm or more CH4, preconcentration is not required and the analysis time is less than 5 min. The system utilizes a commercially available, high-sensitivity isotope-ratio mass spectrometer. For optimal conditions of smaple handling and combustion, performance of the system is within a factor of 2 of the shot-noise limit. The potential exists therefore for analysis of samples as small as 15 pmol CH4 with a standard deviation of less than 1 ppt.

  5. Dust particle injector for hypervelocity accelerators provides high charge-to-mass ratio

    NASA Technical Reports Server (NTRS)

    Berg, O. E.

    1966-01-01

    Injector imparts a high charge-to-mass ratio to microparticles and injects them into an electrostatic accelerator so that the particles are accelerated to meteoric speeds. It employs relatively large masses in the anode and cathode structures with a relatively wide separation, thus permitting a large increase in the allowable injection voltages.

  6. DETERMINATION OF THE ORGANIC MASS TO ORGANIC CARBON RATIO IN IMPROVE SAMPLES. (R831086)

    EPA Science Inventory

    The ratio of organic mass (OM) to organic carbon (OC) in PM2.5 aerosols at US national parks in the IMPROVE network was estimated experimentally from solvent extraction of sample filters and from the difference between PM2.5 mass and chemical constituents...

  7. Charge ratio analysis method: approach for the deconvolution of electrospray mass spectra.

    PubMed

    Maleknia, Simin D; Downard, Kevin M

    2005-01-01

    A new method to interpret electrospray mass spectral data based on calculating the ratio of mass-to-charge (m/z) values of multiply charged ions is described. The mass-to-charge ratios of any two multiply charged ions corresponding to a single compound are unique numbers that enable the charge states for each ion to be unequivocally identified. The multiply charged ions in electrospray mass spectra originate from the addition or abstraction of protons, cations, or anions to and from a compound under analysis. In contrast to existing deconvolution processes, the charge ratio analysis method (CRAM), identifies the charge states of multiply charged ions without any prior knowledge of the nature of the charge-carrying species. In the case of high-resolution electrospray mass spectral data, in which multiply charged ions are resolved to their isotopic components, the CRAM is capable of correlating the isotope peaks of different multiply charged ions that share the same isotopic composition. This relative ratio method is illustrated here for electrospray mass spectral data of lysozyme and oxidized ubiquitin recorded at low- to high-mass resolution on quadrupole ion trap and Fourier transform ion cyclotron mass spectrometers, and theoretical data for the protein calmodulin based upon a reported spectrum recorded on the latter. PMID:15623285

  8. Analytical model for contaminant mass removal by air sparging

    SciTech Connect

    Rabideau, A.J.; Blayden, J.M.

    1998-12-31

    An analytical model was developed to predict the removal of volatile organic compounds (VOCs) from ground water by air sparging (AS). The model treats the air sparging zone as a completely mixed reactor subject to the removal of dissolved contaminants by volatilization, advection, and first-order decay. Nonequilibrium desorption is approximated as a first-order mass transfer process. The model reproduces the tailing and rebound behavior often observed at AS sites, and would normally require the estimation of three site-specific parameters. Dimensional analysis demonstrates that predicting tailing can be interpreted in terms of kinetic desorption or diffusion of aqueous phase contaminants into discrete air channels. Related work is ongoing to test the model against field data.

  9. The mass and speed dependence of meteor air plasma temperatures

    NASA Technical Reports Server (NTRS)

    Jenniskens, Peter; Laux, Christophe O.; Wilson, Michael A.; Schaller, Emily L.

    2004-01-01

    The speed and mass dependence of meteor air plasma temperatures is perhaps the most important data needed to understand how small meteoroids chemically change the ambient atmosphere in their path and enrich the ablated meteoric organic matter with oxygen. Such chemistry can play an important role in creating prebiotic compounds. The excitation conditions in various air plasma emissions were measured from high-resolution optical spectra of Leonid storm meteors during NASA's Leonid Multi-Instrument Aircraft Campaign. This was the first time a sufficient number and range of temperature measurements were obtained to search for meteoroid mass and speed dependencies. We found slight increases in temperature with decreasing altitude, but otherwise nearly constant values for meteoroids with speeds between 35 and 72 km/s and masses between 10(-5) g and 1 g. We conclude that faster and more massive meteoroids produce a larger emission volume, but not a higher air plasma temperature. We speculate that the meteoric plasma may be in multiphase equilibrium with the ambient atmosphere, which could mean lower plasma temperatures in a CO(2)-rich early Earth atmosphere.

  10. Discovery of Seven Companions to Intermediate-mass Stars with Extreme Mass Ratios in the Scorpius-Centaurus Association

    NASA Astrophysics Data System (ADS)

    Hinkley, Sasha; Kraus, Adam L.; Ireland, Michael J.; Cheetham, Anthony; Carpenter, John M.; Tuthill, Peter; Lacour, Sylvestre; Evans, Thomas M.; Haubois, Xavier

    2015-06-01

    We report the detection of seven low-mass companions to intermediate-mass stars (SpT B/A/F; M ˜ 1.5-4.5 M⊙) in the Scorpius-Centaurus (Sco-Cen) Association using nonredundant aperture masking interferometry. Our newly detected objects have contrasts {Δ }L\\prime ≈ 4-6, corresponding to masses as low as ˜20 MJup and mass ratios of q ≈ 0.01-0.08, depending on the assumed age of the target stars. With projected separations ρ ≈ 10-30 AU, our aperture masking detections sample an orbital region previously unprobed by conventional adaptive optics imaging of intermediate-mass Sco-Cen stars covering much larger orbital radii (˜30-3000 AU). At such orbital separations, these objects resemble higher-mass versions of the directly imaged planetary mass companions to the 10-30 Myr, intermediate-mass stars HR 8799, β Pictoris, and HD 95086. These newly discovered companions span the brown dwarf desert, and their masses and orbital radii provide a new constraint on models of the formation of low-mass stellar and substellar companions to intermediate-mass stars. Based on observations made with ESO Telescopes at the La Silla Paranal Observatory Under Program IDs: 0.87.C-0790 and 089.C-0605.

  11. Determination of the organic aerosol mass to organic carbon ratio in IMPROVE samples.

    PubMed

    El-Zanan, Hazem S; Lowenthal, Douglas H; Zielinska, Barbara; Chow, Judith C; Kumar, Naresh

    2005-07-01

    The ratio of organic mass (OM) to organic carbon (OC) in PM(2.5) aerosols at US national parks in the IMPROVE network was estimated experimentally from solvent extraction of sample filters and from the difference between PM(2.5) mass and chemical constituents other than OC (mass balance) in IMPROVE samples from 1988 to 2003. Archived IMPROVE filters from five IMPROVE sites were extracted with dichloromethane (DCM), acetone and water. The extract residues were weighed to determine OM and analyzed for OC by thermal optical reflectance (TOR). On average, successive extracts of DCM, acetone, and water contained 64%, 21%, and 15%, respectively, of the extractable OC, respectively. On average, the non-blank-corrected recovery of the OC initially measured in these samples by TOR was 115+/-42%. OM/OC ratios from the combined DCM and acetone extracts averaged 1.92 and ranged from 1.58 at Indian Gardens, AZ in the Grand Canyon to 2.58 at Mount Rainier, WA. The average OM/OC ratio determined by mass balance was 2.07 across the IMPROVE network. The sensitivity of this ratio to assumptions concerning sulfate neutralization, water uptake by hygroscopic species, soil mass, and nitrate volatilization were evaluated. These results suggest that the value of 1.4 for the OM/OC ratio commonly used for mass and light extinction reconstruction in IMPROVE is too low. PMID:15950041

  12. Measurements of CO in an aircraft experiment and their correlation with biomass burning and air mass origin in South America

    NASA Astrophysics Data System (ADS)

    Boian, C.; Kirchhoff, V. W. J. H.

    Carbon monoxide (CO) measurements are obtained in an aircraft experiment during 1-7 September 2000, conducted over Central Brazil in a special region of anticyclonic circulation. This is a typical transport regime during the dry season (July-September), when intense biomass burning occurs, and which gives origin to the transport of burning poluents from the source to distant regions. This aircraft experiment included in situ measurements of CO concentrations in three different scenarios: (1) areas of fresh biomass burning air masses, or source areas; (2) areas of aged biomass burning air masses; and (3) areas of clean air or pristine air masses. The largest CO concentrations were of the order of 450 ppbv in the source region near Conceicao do Araguaia (PA), and the smallest value near 100 ppbv, was found in pristine air masses, for example, near the northeast coastline (clean air, or background region). The observed concentrations were compared to the number of fire pixels seen by the AVHRR satellite instrument. Backward isentropic trajectories were used to determine the origin of the air masses at each sampling point. From the association of the observed CO mixing ratios, fire pixels and air mass trajectories, the previous scenarios may be subdivided as follows: (1a) source regions of biomass burning with large CO concentrations; (1b) regions with few local fire pixels and absence of contributions by transport. Areas with these characteristics include the northeast region of Brazil; (1c) regions close to the source region and strongly affected by transport (region of Para and Amazonas); (2) regions that have a consistent convergence of air masses, that have traveled over biomass burning areas during a few days (western part of the Cerrado region); (3a) Pristine air masses with origin from the ocean; (3b) regions with convergent transport that has passed over areas of no biomass burning, such as frontal weather systems in the southern regions.

  13. Method and apparatus for varying the fuel ratio of an air-fuel mixture

    SciTech Connect

    Leonardi, S.

    1981-03-24

    A method and apparatus is described for varying the fuel ratio of an air-fuel mixture supplied to the carburetor of an internal combustion engine. In a first embodiment, a valve opens and closes a port in an aluminum block between a passage coupled to the pcv and carburetor and a second passage open to the atmosphere. A spring in the second passage modulates the air flow as a function of vacuum pressure and thermally responsive means maintains the valve closed until the engine reaches its operating temperature. In a second embodiment the valve is opened as a function of the wind pressure produced during vehicle movement.

  14. Relationship between the fractal dimension and the width to length ratio of mass movements

    NASA Astrophysics Data System (ADS)

    Sezer, Ebru

    2009-04-01

    Mass movements have some typical geometrical dimensions. One of these typical geometrical dimensions is the width to length ratio. Also, the fractal dimensions of mass movements from the inventory maps of natural mass movements can be used for their geometrical description and characterization. For this reason, in the present study, development of a computer programme for digitizing and determining the fractal dimensions of mass movements, and investigation of the relationship between the fractal dimensions and the width to length (W/L) tario of the mass movements are aimed. For the purpose of the study, a computer programme namely FRACEK for determination of fractal dimensions of amorphous areas is developed by using the JAVA computer language at first. Secondly, a database including the shapes of the mass movements was compiled from the literature and digitized. Then, their width to length ratios and fractal dimensions were calculated. Finally, a series of simple statistical analyses were performed on the data obtained and the results were interpreted. To investigate the relationships between the fractal dimensions and W/L ratios of the mass movements, a series of simple regression analysis is performed. During the regression analyses, linear, power, logarithmic and exponential functions are employed. According to the results obtained, there are some correlations between the D and the W/L ratio. When considering only debris flow data, a power relationship between the D and the W/L ratio was found and its coefficient of correlation was obtained as 0.85. The lowest coefficient of correlations were obtained from the rotational failure data. The coefficients of correlations of the power and exponential funtions were same, 0.53. A similar result was obtained for the translational failure data. Their coefficient of correlations was 0.74. When all data is evaluated together, a relatively strong correlation between the D and the W/L ratio was obtained. These results

  15. The radial velocity, velocity dispersion, and mass-to-light ratio of the Sculptor dwarf galaxy

    NASA Technical Reports Server (NTRS)

    Armandroff, T. E.; Da Costa, G. S.

    1986-01-01

    The radial velocity, velocity dispersion, and mass-to-light ratio for 16 K giants in the Sculptor dwarf galaxy are calculated. Spectra at the Ca II triplet are analyzed using cross-correlation techniques in order to obtain the mean velocity of + 107.4 + or - 2.0 km/s. The dimensional velocity dispersion estimated as 6.3 (+1.1, -1.3) km/s is combined with the calculated core radius and observed central surface brightness to produce a mass-to-light ratio of 6.0 in solar units. It is noted that the data indicate that the Sculptor contains a large amount of mass not found in globular clusters, and the mass is either in the form of remnant stars or low-mass dwarfs.

  16. A transition in circumbinary accretion discs at a binary mass ratio of 1:25

    NASA Astrophysics Data System (ADS)

    D'Orazio, Daniel J.; Haiman, Zoltán; Duffell, Paul; MacFadyen, Andrew; Farris, Brian

    2016-07-01

    We study circumbinary accretion discs in the framework of the restricted three-body problem (R3Bp) and via numerically solving the height-integrated equations of viscous hydrodynamics. Varying the mass ratio of the binary, we find a pronounced change in the behaviour of the disc near mass ratio q ≡ Ms/Mp ˜ 0.04. For mass ratios above q = 0.04, solutions for the hydrodynamic flow transition from steady, to strongly fluctuating; a narrow annular gap in the surface density around the secondary's orbit changes to a hollow central cavity; and a spatial symmetry is lost, resulting in a lopsided disc. This phase transition is coincident with the mass ratio above which stable orbits do not exist around the L4 and L5 equilibrium points of the R3Bp. Using the DISCO code, we find that for thin discs, for which a gap or cavity can remain open, the mass ratio of the transition is relatively insensitive to disc viscosity and pressure. The q = 0.04 transition has relevance for the evolution of massive black hole binary+disc systems at the centres of galactic nuclei, as well as for young stellar binaries and possibly planets around brown dwarfs.

  17. Performance and emission characteristics of swirl-can combustors to near-stoichiometric fuel-air ratio

    NASA Technical Reports Server (NTRS)

    Diehl, L. A.; Trout, A. M.

    1976-01-01

    Emissions and performance characteristics were determined for two full annular swirl-can combustors operated to near stoichiometric fuel-air ratio. Test condition variations were as follows: combustor inlet-air temperatures, 589, 756, 839, and 894 K; reference velocities, 24 to 37 meters per second; inlet pressure, 62 newtons per square centimeter; and fuel-air ratios, 0.015 to 0.065. The combustor average exit temperature and combustor efficiency were calculated from the combustor exhaust gas composition. For fuel-air ratios greater than 0.04, the combustion efficiency decreased with increasing fuel-air ratios in a near-linear manner. Increasing the combustor inlet air temperature tended to offset this decrease. Maximum oxides of nitrogen emission indices occurred at intermediate fuel-air ratios and were dependent on combustor design. Carbon monoxide levels were extremely high and were the primary cause of poor combustion efficiency at the higher fuel-air ratios. Unburned hydrocarbons were low for all test conditions. For high fuel-air ratios SAE smoke numbers greater than 25 were produced, except at the highest inlet-air temperatures.

  18. ASAS J083241+2332.4: A New Extreme Low Mass Ratio Overcontact Binary System

    NASA Astrophysics Data System (ADS)

    Sriram, K.; Malu, S.; Choi, C. S.; Vivekananda Rao, P.

    2016-03-01

    We present the R- and V-band CCD photometry and Hα line studies of an overcontact binary ASAS J083241+2332.4. The light curves exhibit totality along with a trace of the O’Connell effect. The photometric solution indicates that this system falls into the category of extreme low-mass ratio overcontact binaries with a mass ratio, q ˜ 0.06. Although a trace of the O’ Connell effect is observed, constancy of the Hα line along various phases suggest that a relatively higher magnetic activity is needed for it to show a prominent fill-in effect. The study of O-C variations reveals that the period of the binary shows a secular increase at the rate of dP/dt ˜ 0.0765 s years-1, which is superimposed by a low, but significant, sinusoidal modulation with a period of ˜8.25 years. Assuming that the sinusoidal variation is due to the presence of a third body, orbital elements have been derived. There exist three other similar systems, SX Crv, V857 Her, and E53, which have extremely low mass ratios and we conclude that ASAS J083241+2332.4 resembles SX Crv in many respects. Theoretical studies indicate that at a critical mass ratio range, qcritical = 0.07-0.09, overcontact binaries should merge and form a fast rotating star, but it has been suggested that qcritical can continue to fall up to 0.05 depending on the primary's mass and structure. Moreover, the obtained fill-out factors (50%-70%) indicate that mass loss is considerable and hydrodynamical simulations advocate that mass loss from L2 is mandatory for a successful merging process. Comprehensively, the results indicate that ASAS J083241+2332.4 is at a stage of merger. The pivotal role played by the subtle nature of the derived mass ratio in forming a rapidly rotating star has been discussed.

  19. Co-injection of air and steam for the prevention of the downward migration of DNAPLs during steam enhanced extraction: an experimental evaluation of optimum injection ratio predictions.

    PubMed

    Kaslusky, Scott F; Udell, Kent S

    2005-05-01

    When steam is injected into soil containing a dense volatile non-aqueous phase liquid contaminant, the DNAPL vaporized within the heated soil region condenses and accumulates ahead of the steam condensation front. If enough DNAPL accumulates, gravitational forces can overcome trapping forces allowing the liquid contaminant to flow downward. By injecting air with steam, a portion of the DNAPL vapor remains suspended in equilibrium with the air, decreasing liquid contaminant accumulation ahead of the steam condensation front, and thus reducing the possibility of downward migration. In a previous work, a theoretical model was developed to predict the optimum injection ratio of air to steam that would eliminate accumulation of DNAPL ahead of the temperature front and thus minimize the potential for downward migration. In this work, the theoretical model is summarized, and an experiment is presented in order to evaluate the optimum injection ratio prediction. In the experiment, a two-dimensional water saturated sand pack is contaminated with a known mass of TCE (DNAPL). The system is then remediated by co-injecting air and steam at the predicted optimum injection ratio, calculated based on the average contaminant soil concentration in the sand pack. Results for the co-injection of air and steam are compared to results for the injection of pure steam or pure air. Injection at the predicted optimum injection ratio for a volumetric average NAPL saturation, reduced accumulation of the contaminant ahead of the condensation front by over 90%, as compared to steam injection alone. This indicates that the optimum injection ratio prediction is a valuable tool for limiting the spreading of DNAPL during steam-enhanced extraction. Injection at the optimum injection ratio resulted in earlier recovery of contaminant than for steam injection alone. Co-injection of steam and air is also shown to result in much higher recovery rates than air injection alone. PMID:15854722

  20. Body mass index and waist: hip ratio are not enough to characterise female attractiveness.

    PubMed

    Pokrywka, Leszek; Cabrić, Milan; Krakowiak, Helena

    2006-01-01

    The assessment of characteristic body features of Miss Poland beauty contest finalists compared with the control group, can contribute to recognising the contemporary ideal of beauty promoted by the mass media. The studies of Playboy models and fashion models conducted so far have been limited to the following determinants of attractiveness: body mass index, waist:hip ratio, and waist:chest ratio, which only partially describe the body shape. We compared 20 body features of the finalists of Miss Poland 2004 beauty contest with those of the students of Medical Academy in Bydgoszcz. Discriminant analysis showed that the thigh girth-height index, waist: chest ratio, height, and body mass index had the greatest discrimination power distinguishing the two groups. A model of Miss Poland finalists figure assessment is presented which allows one to distinguish super-attractive women from the control group. PMID:17283934

  1. Orientation of X Lines in Asymmetric Magnetic Reconnection-Mass Ratio Dependency

    NASA Technical Reports Server (NTRS)

    Liu, Yi-Hsin; Hesse, M.; Kuznetsova, M.

    2015-01-01

    Using fully kinetic simulations, we study the X line orientation of magnetic reconnection in an asymmetric configuration. A spatially localized perturbation is employed to induce a single X line, which has sufficient freedom to choose its orientation in three-dimensional systems. The effect of ion to electron mass ratio is investigated, and the X line appears to bisect the magnetic shear angle across the current sheet in the large mass ratio limit. The orientation can generally be deduced by scanning through the corresponding 2-D simulations to find the reconnection plane that maximizes the peak reconnection electric field. The deviation from the bisection angle in the lower mass ratio limit is consistent with the orientation shift of the most unstable linear tearing mode in an electron-scale current sheet.

  2. Isotope ratio monitoring of small molecules and macromolecules by liquid chromatography coupled to isotope ratio mass spectrometry.

    PubMed

    Godin, Jean-Philippe; Hau, Jörg; Fay, Laurent-Bernard; Hopfgartner, Gérard

    2005-01-01

    In the field of isotope ratio mass spectrometry, the introduction of an interface allowing the connection of liquid chromatography (LC) and isotope ratio mass spectrometry (IRMS) has opened a range of new perspectives. The LC interface is based on a chemical oxidation, producing CO2 from organic molecules. While first results were obtained from the analysis of low molecular weight compounds, the application of compound-specific isotope analysis by irm-LC/MS to other molecules, in particular biomolecules, is presented here. The influence of the LC flow rate on the CO2 signal and on the observed delta13C values is demonstrated. The limits of quantification for angiotensin III and for leucine were 100 and 38 pmol, respectively, with a standard deviation of the delta13C values better than 0.4 per thousand. Also, accuracy and precision of delta13C values for elemental analyser-IRMS and flow injection analysis-IRMS (FIA-LC/MS) were compared. For compounds with molecular weights ranging from 131 to 66,390 Da, precision was better than 0.3 per thousand, and accuracy varied from 0.1 to 0.7 per thousand. In a second part of the work, a two-dimensional (2D)-LC method for the separation of 15 underivatised amino acids is demonstrated; the precision of delta13C values for several amino acids by irm-LC/MS was better than 0.3 per thousand at natural abundance. For labelled mixtures, the coefficient of variation was between 1% at 0.07 atom % excess (APE) for threonine and alanine, and around 10% at 0.03 APE for valine and phenylalanine. The application of irm-LC/MS to the determination of the isotopic enrichment of 13C-threonine in an extract of rat colon mucosa demonstrated a precision of 0.5 per thousand, or 0.001 atom %. PMID:16124031

  3. Continuous Measurements of Dissolved Ne, Ar, Kr, and Xe Ratios with a Field-Deployable Gas Equilibration Mass Spectrometer.

    PubMed

    Manning, Cara C; Stanley, Rachel H R; Lott, Dempsey E

    2016-03-15

    Noble gases dissolved in natural waters are useful tracers for quantifying physical processes. Here, we describe a field-deployable gas equilibration mass spectrometer (GEMS) that provides continuous, real-time measurements of Ne, Ar, Kr, and Xe mole ratios in natural waters. Gas is equilibrated with a membrane contactor cartridge and measured with a quadrupole mass spectrometer, after in-line purification with reactive metal alloy getters. We use an electron energy of 35 V for Ne to eliminate isobaric interferences, and a higher electron energy for the other gases to improve sensitivity. The precision is 0.7% or better and 1.0% or better for all mole ratios when the instrument is installed in a temperature-controlled environment and a variable-temperature environment, respectively. In the lab, the accuracy is 0.9% or better for all gas ratios using air as the only calibration standard. In the field (and/or at greater levels of disequilbrium), the accuracy is 0.7% or better for Ne/Kr, Ne/Ar, and Ar/Kr, and 2.5% or better for Ne/Xe, Ar/Xe, and Kr/Xe using air as the only calibration standard. The field accuracy improves to 0.6% or better for Ne/Xe, Ar/Xe, and Kr/Xe when the data is calibrated using discrete water samples run on a laboratory-based mass spectrometer. The e-folding response time is 90-410 s. This instrument enables the collection of a large number of continuous, high-precision and accuracy noble gas measurements at substantially reduced cost and labor compared to traditional methods. PMID:26854788

  4. Estimation of mass ratio of the total kernels within a sample of in-shell peanuts using RF Impedance Method

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It would be useful to know the total kernel mass within a given mass of peanuts (mass ratio) while the peanuts are bought or being processed. In this work, the possibility of finding this mass ratio while the peanuts were in their shells was investigated. Capacitance, phase angle and dissipation fa...

  5. Experimental simulation of air quality in street canyon under changes of building orientation and aspect ratio.

    PubMed

    Yassin, Mohamed F; Ohba, Masaake

    2012-09-01

    To assist validation of numerical simulations of urban pollution, air quality in a street canyon was investigated using a wind tunnel as a research tool under neutral atmospheric conditions. We used tracer gas techniques from a line source without buoyancy. Ethylene (C(2)H(4)) was used as the tracer gas. The street canyon model was formed of six parallel building rows of the same length. The flow and dispersion field was analyzed and measured using a hot-wire anemometer with split fiber probe and fast flame ionization detector. The diffusion flow field in the boundary layer within the street canyon was examined at different locations, with varying building orientations (θ=90°, 112.5°, 135° and 157.5°) and street canyon aspect ratios (W/H=1/2, 3/4 and 1) downwind of the leeward side of the street canyon model. Results show that velocity increases with aspect ratio, and with θ>90°. Pollutant concentration increases as aspect ratio decreases. This concentration decreases exponentially in the vertical direction, and decreases as θ increases from 90°. Measured pollutant concentration distributions indicate that variability of building orientation and aspect ratio in the street canyon are important for estimating air quality in the canyon. The data presented here can be used as a comprehensive database for validation of numerical models. PMID:22760437

  6. Period change investigation of the low mass ratio contact binary BO Ari

    NASA Astrophysics Data System (ADS)

    Kriwattanawong, W.; Tasuya, O.; Poojon, P.

    2016-04-01

    A photometric study and period change analysis for the A-type low mass ratio contact binary BO Ari is presented. The BVR light curves were fitted by using the Wilson-Devinney method. The photometric solution yields a low mass ratio of q = 0.1754(±0.0016) with a contact degree of f = 27.72%(±2.37%). We found a long-term orbital period decrease at a rate of dPdt = - 3.49 ×10-7 d yr-1. This result indicates that the system is undergoing mass transfer from the primary component to the secondary with a mass transfer rate of m˙1m1 = - 7.77 ×10-8 yr-1. With the period decrease, the inner and outer critical Roche surfaces will tighten and cause the degree of contact to increase. Therefore, BO Ari may evolve into a deeper contact system.

  7. Precision Test of Mass-Ratio Variations with Lattice-Confined Ultracold Molecules

    SciTech Connect

    Zelevinsky, T.; Ye Jun; Kotochigova, S.

    2008-02-01

    We propose a precision measurement of time variations of the proton-electron mass ratio using ultracold molecules in an optical lattice. Vibrational energy intervals are sensitive to changes of the mass ratio. In contrast to measurements that use hyperfine-interval-based atomic clocks, the scheme discussed here is model independent and does not require separation of time variations of different physical constants. The possibility of applying the zero-differential-Stark-shift optical lattice technique is explored to measure vibrational transitions at high accuracy.

  8. Precision test of mass-ratio variations with lattice-confined ultracold molecules.

    PubMed

    Zelevinsky, T; Kotochigova, S; Ye, Jun

    2008-02-01

    We propose a precision measurement of time variations of the proton-electron mass ratio using ultracold molecules in an optical lattice. Vibrational energy intervals are sensitive to changes of the mass ratio. In contrast to measurements that use hyperfine-interval-based atomic clocks, the scheme discussed here is model independent and does not require separation of time variations of different physical constants. The possibility of applying the zero-differential-Stark-shift optical lattice technique is explored to measure vibrational transitions at high accuracy. PMID:18352267

  9. Protein/Arabinoxylans Gels: Effect of Mass Ratio on the Rheological, Microstructural and Diffusional Characteristics

    PubMed Central

    Berlanga-Reyes, Claudia M.; Carvajal-Millan, Elizabeth; Hicks, Kevin B.; Yadav, Madhav P.; Rascón-Chu, Agustín; Lizardi-Mendoza, Jaime; Toledo-Guillén, Alma R.; Islas-Rubio, Alma R.

    2014-01-01

    Wheat bran arabinoxylan (WBAX) gels entrapping standard model proteins at different mass ratios were formed. The entrapment of protein affected the gel elasticity and viscosity values, which decreased from 177 to 138 Pa. The presence of protein did not modify the covalent cross-links content of the gel. The distribution of protein through the network was investigated by confocal laser scanning microscopy. In mixed gels, protein aggregates forming clusters were detected at protein/polysaccharide ratios higher than 0.25. These clusters were not homogeneously distributed, suggesting that WBAX and protein are located in two different phases. The apparent diffusion coefficient (Dm) of proteins during release from mixed gels was investigated for mass ratios of 0.06 and 0.12. For insulin, Dm increased significantly from 2.64 × 10−7 to 3.20 × 10−7 cm2/s as the mass ratio augmented from 0.06 to 0.12. No significant difference was found for Dm values of ovalbumin and bovine serum albumin released from the mixed gels. The results indicate that homogeneous protein/WBAX gels can be formed at low mass ratios, allowing the estimation of Dm by using an analytical solution of the second Fick’s law. PMID:25338049

  10. Protein/arabinoxylans gels: effect of mass ratio on the rheological, microstructural and diffusional characteristics.

    PubMed

    Berlanga-Reyes, Claudia M; Carvajal-Millan, Elizabeth; Hicks, Kevin B; Yadav, Madhav P; Rascón-Chu, Agustín; Lizardi-Mendoza, Jaime; Toledo-Guillén, Alma R; Islas-Rubio, Alma R

    2014-01-01

    Wheat bran arabinoxylan (WBAX) gels entrapping standard model proteins at different mass ratios were formed. The entrapment of protein affected the gel elasticity and viscosity values, which decreased from 177 to 138 Pa. The presence of protein did not modify the covalent cross-links content of the gel. The distribution of protein through the network was investigated by confocal laser scanning microscopy. In mixed gels, protein aggregates forming clusters were detected at protein/polysaccharide ratios higher than 0.25. These clusters were not homogeneously distributed, suggesting that WBAX and protein are located in two different phases. The apparent diffusion coefficient (Dm) of proteins during release from mixed gels was investigated for mass ratios of 0.06 and 0.12. For insulin, Dm increased significantly from 2.64 × 10-7 to 3.20 × 10-7 cm2/s as the mass ratio augmented from 0.06 to 0.12. No significant difference was found for Dm values of ovalbumin and bovine serum albumin released from the mixed gels. The results indicate that homogeneous protein/WBAX gels can be formed at low mass ratios, allowing the estimation of Dm by using an analytical solution of the second Fick's law. PMID:25338049

  11. VOC Composition of Air Masses Transported from Asia to the U.S. West Coast

    NASA Astrophysics Data System (ADS)

    de Gouw, J.; Warneke, C.; Kuster, B.; Parrish, D.; Holloway, J.; Huebler, G.; Fehsenfeld, F.

    2002-12-01

    Airborne measurements of volatile organic compounds (VOCs) were performed using a proton-transfer-reaction mass spectrometer (PTR-MS) operated onboard a NOAA WP-3 aircraft during the Intercontinental Transport and Chemical Transformation (ITCT) experiment in 2002. Enhancements of acetone (CH3COCH3), methanol (CH3OH), acetonitrile (CH3CN) and in some cases benzene were observed in air masses that were impacted by outflow from Asia. The enhancement ratios with respect to carbon monoxide are compared to emission factors for fossil fuel combustion and biomass burning, which gives some insight into the sources responsible for the pollution. The observed mixing ratios for acetone, methanol and in particular acetonitrile were generally reduced in the marine boundary layer, suggesting the presence of an ocean uptake sink. The ocean uptake of acetonitrile was found to be particularly efficient in a zone with upwelling water off of the U.S. west coast. Reduced mixing ratios of acetone and methanol were observed in a stratospheric intrusion. This observation gives some information about the lifetime of these VOCs in the stratosphere. Enhanced concentrations of aromatic hydrocarbons were observed in air masses that were impacted by urban sources in California. The ratio between the concentrations of benzene, toluene and higher aromatics indicated the degree of photochemical oxidation. PTR-MS only gives information about the mass of the ions produced by proton-transfer reactions between H3O+ and VOCs in the instrument. The identification of VOCs was confirmed by coupling a gas-chromatographic (GC) column to the instrument and post-flight GC-PTR-MS analyses of canister samples collected during the flights.

  12. Effect of mass ratio on fluid induced motions of a circular cylinder with strips

    NASA Astrophysics Data System (ADS)

    Vinod, Ashwin; Banerjee, Arindam

    2014-11-01

    The objective of the current experimental work is to investigate the effects of mass ratio on Fluid Induced Motions, such as vortex induced vibration (VIV) and galloping, of elastically mounted circular cylinders attached with strips to their outer surface. Although the effect of mass ratio on VIV of a smooth circular cylinder is well documented in literature, however, their effects on circular cylinders with strips, capable of inciting galloping oscillations haven't been investigated and could have potential applications in the domain of vibration based energy harvesters. In the current work, three different mass ratios were tested, out of which, one falls below the critical mass in vortex induced vibration of a circular cylinder. The strips used for the experiments included sandpaper strips of prescribed roughness and smooth strips with no roughness, both of which served as surface protrusion based mechanisms of altering the flow around the cylinder. Interesting variations were observed in the amplitude, frequency response and the power spectrum, depending on the mass ratio of the oscillating system tested. The authors acknowledge support of the Office of Naval Research (Grant # ONR-000141210495 - Dr. Ron Joslin).

  13. Ratio

    NASA Astrophysics Data System (ADS)

    Webster, Nathan A. S.; Pownceby, Mark I.; Madsen, Ian C.; Studer, Andrew J.; Manuel, James R.; Kimpton, Justin A.

    2014-12-01

    Effects of basicity, B (CaO:SiO2 ratio) on the thermal range, concentration, and formation mechanisms of silico-ferrite of calcium and aluminum (SFCA) and SFCA-I iron ore sinter bonding phases have been investigated using an in situ synchrotron X-ray diffraction-based methodology with subsequent Rietveld refinement-based quantitative phase analysis. SFCA and SFCA-I phases are the key bonding materials in iron ore sinter, and improved understanding of the effects of processing parameters such as basicity on their formation and decomposition may assist in improving efficiency of industrial iron ore sintering operations. Increasing basicity significantly increased the thermal range of SFCA-I, from 1363 K to 1533 K (1090 °C to 1260 °C) for a mixture with B = 2.48, to ~1339 K to 1535 K (1066 °C to 1262 °C) for a mixture with B = 3.96, and to ~1323 K to 1593 K (1050 °C to 1320 °C) at B = 4.94. Increasing basicity also increased the amount of SFCA-I formed, from 18 wt pct for the mixture with B = 2.48 to 25 wt pct for the B = 4.94 mixture. Higher basicity of the starting sinter mixture will, therefore, increase the amount of SFCA-I, considered to be more desirable of the two phases. Basicity did not appear to significantly influence the formation mechanism of SFCA-I. It did, however, affect the formation mechanism of SFCA, with the decomposition of SFCA-I coinciding with the formation of a significant amount of additional SFCA in the B = 2.48 and 3.96 mixtures but only a minor amount in the highest basicity mixture. In situ neutron diffraction enabled characterization of the behavior of magnetite after melting of SFCA produced a magnetite plus melt phase assemblage.

  14. Determination of the Charon/Pluto Mass Ratio from Center-of-Light Astrometry

    NASA Technical Reports Server (NTRS)

    Foust, Jeffrey A.; Elliot, J. L.; Olkin, Catherine B.; McDonald, Stephen W.; Dunham, Edward W.; Stone, Remington P. S.; McDonald, John S.; Stone, Ronald C.

    1997-01-01

    The Charon/Pluto mass ratio is a fundamental but poorly known parameter of the two-body system. Previous values for the mass ratio have ranged from 0.0837 plus or minus 0.0147 (Null et al., 1993, Astron. J. 105, 2319-2335) to 0.1566 plus or minus 0.0035 (Young et al., 1994, Icarus 108,186-199). We report here a new determination of the Charon/Pluto mass ratio, using five sets of groundbased images taken at four sites in support of Pluto occultation predictions. Unlike the Null et al. and Young et A determinations, where the centers of light for Pluto and Charon could be determined separately, this technique examines the motion of the center of light of the blended Pluto-Charon image. We compute the offsets of the observed center-of-light position of Pluto-Charon from the ephemeris position of the system and fit these offsets to a model of the Pluto-Charon system. The least-squares fits to the five data sets agree within their errors, and the weighted mean mass ratio is 0.117 plus or minus 0.006. The effects of errors in the Charon light fraction, semimajor axis, and ephemeris have been examined and are equal to only a small fraction of the formal error from the fit. This result is intermediate between those of Null et al., and Young et al. and matches a new value of 0.124 plus or minus 0.008 by Null and Owen (1996, Astron. J. 111, 1368-1381). The mass ratio and resulting individual masses and densities of Pluto and Charon are consistent with a collisional origin for the Pluto-Charon system.

  15. Mass Ratio Determination from H α Lines in Black Hole X-Ray Transients

    NASA Astrophysics Data System (ADS)

    Casares, J.

    2016-05-01

    We find that the mass ratio q in quiescent black hole (BH) X-ray transients is tightly correlated with the ratio of the double-peak separation (DP) to the full width half maximum (FWHM) of the H α emission line, {log}q=-6.88-23.2\\quad {log}({DP}/{FWHM}). This correlation is explained through the efficient truncation of the outer disk radius by the 3:1 resonance with the companion star. This is the dominant tidal interaction for extreme mass ratios q={M}2/{M}1≲ 0.25, the realm of BH (and some neutron star) X-ray transients. Mass ratios can thus be estimated with a typical uncertainty of ≈32%, provided that the H α profile used to measure DP/FWHM is an orbital phase average. We apply the DP/FWHM–q relation to the three faint BH transients XTE J1650–500, XTE J1859+226, and Swift J1357–0933 and predict q={0.026}-0.007+0.038, {0.049}-0.012+0.023 and {0.040}-0.005+0.003, respectively. This new relation, together with the {FWHM}{--}{K}2 correlation presented in Paper I, allows the extraction of fundamental parameters from very faint targets and, therefore, the extension of dynamical BH studies to much deeper limits than was previously possible. As an example, we combine our mass ratio determination for Swift J1357–0933 with previous reported values to yield a BH mass of 12.4 ± 3.6 M ⊙. This confirms Swift J1357–0933 as one of the most massive BH low-mass X-ray binaries in the Galaxy.

  16. Fermion mass hierarchy and nonhierarchical mass ratios in SU(5)xU(1){sub F}

    SciTech Connect

    Duque, Luis F.; Gutierrez, Diego A.; Nardi, Enrico; Norena, Jorge

    2008-08-01

    We consider a SU(5)xU(1){sub F} grand unified theory (GUT)-flavor model in which the number of effects that determine the charged fermions Yukawa matrices is much larger than the number of observables, resulting in a hierarchical fermion spectrum with no particular regularities. The GUT-flavor symmetry is broken by flavons in the adjoint of SU(5), realizing a variant of the Froggatt-Nielsen mechanism that gives rise to a large number of effective operators. By assuming a common mass for the heavy fields and universality of the fundamental Yukawa couplings, we reduce the number of free parameters to one. The observed fermion mass spectrum is reproduced thanks to selection rules that discriminate among various contributions. Bottom-tau Yukawa unification is preserved at leading order, but there is no unification for the first two families. Interestingly, U(1){sub F} charges alone do not determine the hierarchy, and can only give upper bounds on the parametric suppression of the Yukawa operators.

  17. Modelling heat and mass transfer in a membrane-based air-to-air enthalpy exchanger

    NASA Astrophysics Data System (ADS)

    Dugaria, S.; Moro, L.; Del, D., Col

    2015-11-01

    The diffusion of total energy recovery systems could lead to a significant reduction in the energy demand for building air-conditioning. With these devices, sensible heat and humidity can be recovered in winter from the exhaust airstream, while, in summer, the incoming air stream can be cooled and dehumidified by transferring the excess heat and moisture to the exhaust air stream. Membrane based enthalpy exchangers are composed by different channels separated by semi-permeable membranes. The membrane allows moisture transfer under vapour pressure difference, or water concentration difference, between the two sides and, at the same time, it is ideally impermeable to air and other contaminants present in exhaust air. Heat transfer between the airstreams occurs through the membrane due to the temperature gradient. The aim of this work is to develop a detailed model of the coupled heat and mass transfer mechanisms through the membrane between the two airstreams. After a review of the most relevant models published in the scientific literature, the governing equations are presented and some simplifying assumptions are analysed and discussed. As a result, a steady-state, two-dimensional finite difference numerical model is setup. The developed model is able to predict temperature and humidity evolution inside the channels. Sensible and latent heat transfer rate, as well as moisture transfer rate, are determined. A sensitive analysis is conducted in order to determine the more influential parameters on the thermal and vapour transfer.

  18. Waist-to-Height Ratio and Body Mass Index as Indicators of Cardiovascular Risk in Youth

    ERIC Educational Resources Information Center

    Keefer, Daniel J.; Caputo, Jennifer L.; Tseh, Wayland

    2013-01-01

    Background: The purpose of this investigation was to determine if waist-to-height ratio (WHTR) or body mass index (BMI) is the better indicator of cardiovascular disease risk in children and adolescents of varying ages. Methods: Data from children and adolescents (N?=?2300) who were part of the 2003-2004 National Health and Nutrition Examination…

  19. ASASSN-16do confirmed as high inclination, low mass ratio CV

    NASA Astrophysics Data System (ADS)

    Britt, Christopher; Maccarone, Thomas; Strader, Jay; Chomiuk, Laura

    2016-04-01

    After a very broad, double peaked H alpha line of this object first reported in ATEL #8888 was detected in ATEL #8969, we measured the separation between the peaks in light of the new relation DP/FWHM to mass ratio q (Casares, 2016) where DP is the separation between the peaks.

  20. Analytical techniques in biomedical stable isotope applications: (isotope ratio) mass spectrometry or infrared spectrometry?

    PubMed

    Stellaard, Frans; Elzinga, Henk

    2005-12-01

    An overview is presented of biomedical applications of stable isotopes in general, but mainly focused on the activities of the Center for Liver, Digestive and Metabolic Diseases of the University Medical Center Groningen. The aims of metabolic studies in the areas of glucose, fat, cholesterol and protein metabolism are briefly explained, as well as the principle of breath testing and the techniques to study body composition and energy expenditure. Much attention is paid to the analytical considerations based upon metabolite concentrations, sample size restrictions, the availability of stable isotope labelled substrates and dose requirements in relation to compound-specific isotope analysis. The instrumental advantages and limitations of the generally used techniques gas chromatography/reaction/isotope ratio mass spectrometry and gas chromatography/mass spectrometry are described as well as the novelties of the recently commercialised liquid chromatography/combustion/isotope ratio mass spectrometry. The present use and future perspective of infrared (IR) spectrometry for clinical and biomedical stable isotope applications are reviewed. In this respect, the analytical demands on IR spectrometry are discussed to enable replacement of isotope ratio mass spectrometry by IR spectrometry, in particular, for the purpose of compound-specific isotope ratio analysis in biological matrices. PMID:16543190

  1. Protein/Arabinoxylans Gels: Effect of mass ratio on the rheological, microstructural and diffusional characteristics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Arabinoxylan (AX) gels entrapping standard model proteins at different mass ratios were formed. The distribution of protein through the network was investigated by confocal laser scanning microscopy (CLSM). In mixed gels, protein aggregates forming clusters were detected at protein/polysaccharide ra...

  2. Analytical determination of the aerosol organic mass-to-organic carbon ratio.

    PubMed

    El-Zanan, Hazem S; Zielinska, Barbara; Mazzoleni, Lynn R; Hansen, D Alan

    2009-01-01

    Particulate matter (PM) with an aerodynamic diameter < or = 2.5 microm (PM2.5) was collected daily (mid-July 1998 to the end of December 1999) over a 24-hr sampling period in a mixed light industrial-residential area in Atlanta, GA, to provide a subset of data for the Aerosol Research and Inhalation Epidemiology Study (ARIES). This study included the measurement of organic carbon (OC), elemental carbon (EC), and individual organic compounds. OC and EC average mean concentrations were 4.50 +/- 0.33 and 2.08 +/- 0.19 microg/m3, respectively. The ratio of organic matter mass (OM) to OC in PM2.5 aerosols in Atlanta was measured using three different approaches: (1) solvent extract residue gravimetric masses to individual OC concentrations of sequential apolar to polar solvent extracts (dichloromethane, acetone, and water); (2) mass balance of the PM2.5 measured gravimetric mass minus the mass concentrations of the inorganic/elemental constituents to the total OC concentration; and (3) polar organic compound speciation with the concentration weighted ratio to the total OC concentration. We found very good agreement between approach 1 and 2. The average OM/OC ratio calculated from the extract residue mass was 2.14 +/- 0.17. The average OM/OC ratio determined by mass balance was 2.16 +/- 0.43 for the whole period. The concentration weighted ratio calculated from the concentrations of polar organic compounds ranged between 1.55 and 1.72, which was likely a lower limit for the ratio because of the limited number of the polar organic compounds that can be quantified using gas chromatographic methods. We found seasonal differences with an OM/OC range of 1.77 in December 1999 to 2.39 in July 1999. These results suggest that the previously accepted value of 1.4 for the OM/OC ratio was too low even for urban locations during the winter months. Molecular-level speciation of the PM2.5-associated organic compounds showed that the concentrations of the molecular markers for wood

  3. Growth and activity of black holes in galaxy mergers with varying mass ratios

    NASA Astrophysics Data System (ADS)

    Capelo, Pedro R.; Volonteri, Marta; Dotti, Massimo; Bellovary, Jillian M.; Mayer, Lucio; Governato, Fabio

    2015-03-01

    We study supermassive black holes (BHs) in merging galaxies, using a suite of hydrodynamical simulations with very high spatial (˜10 pc) and temporal (˜1 Myr) resolution, where we vary the initial mass ratio, the orbital configuration, and the gas fraction. (i) We address the question of when and why, during a merger, increased BH accretion occurs, quantifying gas inflows and BH accretion rates. (ii) We also quantify the relative effectiveness in inducing active galactic nuclei activity of merger-related versus secular-related causes, by studying different stages of the encounter: the stochastic (or early) stage, the (proper) merger stage, and the remnant (or late) stage. (iii) We assess which galaxy mergers preferentially enhance BH accretion, finding that the initial mass ratio is the most important factor. (iv) We study the evolution of the BH masses, finding that the BH mass contrast tends to decrease in minor mergers and to increase in major mergers. This effect hints at the existence of a preferential range of mass ratios for BHs in the final pairing stages. (v) In both merging and dynamically quiescent galaxies, the gas accreted by the BH is not necessarily the gas with low angular momentum, but the gas that loses angular momentum.

  4. Alleviation of overlap interferences for determination of potassium isotope ratios by inductively coupled plasma mass spectrometry

    SciTech Connect

    Jiang, S.J.; Houk, R.S.; Stevens, M.A.

    1988-06-01

    Positioning the sampling orifice relatively far from the load coil combined with use of low forward power and high aerosol gas flow rate causes the background mass spectrum to become dominated by NO/sup +/. Nearly all the Ar/sup +/ and ArH/sup +/ ions are suppressed under these conditions, which frees m/z 39 and 41 for potassium isotope ratio measurements. The precision is 0.3-0.9% relative standard deviation for potassium concentrations in the range 1-50 mg L/sup -1/. The determined ratios are approx. 9% higher than the accepted value and also vary with the concentration of sodium concomitant, so calibrations and chemical separations are desirable. These observations should permit use of inductively coupled plasma mass spectrometry for rapid isotope ratio determinations of potassium from biological organisms or water sources.

  5. Measurement of M{sub ital W} using the transverse mass ratio of W and Z

    SciTech Connect

    Rajagopalan, S.; Rijssenbeek, M.; D0 Collaboration

    1996-12-31

    We report on the measurement of W boson mass from a determination of the ratio of the transverse masses of {ital W} and {ital Z} using the DO detector at the Fermilab Tevatron {ital p{anti p}} Collider operating at {radical}{ital s} = 1.8 TeV. The analysis is a preliminary result based on a partial data sample of 13 pb{sup -1} using W {r_arrow} {ital e{sup -}{mu}{sup +}} and Z {r_arrow} {ital e{sup -}e{sup +}} decays. The mass ratio can also be extracted by comparing the shapes of the electron E{sub T} and & distribution from W and Z decays.

  6. Stable oxygen and hydrogen isotopes of brines - comparing isotope ratio mass spectrometry and isotope ratio infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Ahrens, Christian; Koeniger, Paul; van Geldern, Robert; Stadler, Susanne

    2013-04-01

    Today's standard analytical methods for high precision stable isotope analysis of fluids are gas-water equilibration and high temperature pyrolysis coupled to isotope ratio mass spectrometers (IRMS). In recent years, relatively new laser-based analytical instruments entered the market that are said to allow high isotope precision data on nearly every media. This optical technique is referred to as isotope ratio infrared spectroscopy (IRIS). The objective of this study is to evaluate the capability of this new instrument type for highly saline solutions and a comparison of the analytical results with traditional IRMS analysis. It has been shown for the equilibration method that the presence of salts influences the measured isotope values depending on the salt concentration (see Lécuyer et al, 2009; Martineau, 2012). This so-called 'isotope salt effect' depends on the salt type and salt concentration. These factors change the activity in the fluid and therefore shift the isotope ratios measured by the equilibration method. Consequently, correction factors have to be applied to these analytical data. Direct conversion techniques like pyrolysis or the new laser instruments allow the measurement of the water molecule from the sample directly and should therefore not suffer from the salt effect, i.e. no corrections of raw values are necessary. However, due to high salt concentrations this might cause technical problems with the analytical hardware and may require labor-intensive sample preparation (e.g. vacuum distillation). This study evaluates the salt isotope effect for the IRMS equilibration technique (Thermo Gasbench II coupled to Delta Plus XP) and the laser-based IRIS instruments with liquid injection (Picarro L2120-i). Synthetic salt solutions (NaCl, KCl, CaCl2, MgCl2, MgSO4, CaSO4) and natural brines collected from the Stassfurt Salt Anticline (Germany; Stadler et al., 2012) were analysed with both techniques. Salt concentrations ranged from seawater salinity

  7. Characteristics of dimethylsulfide, ozone, aerosols, and cloud condensation nuclei in air masses over the northwestern Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Nagao, Ippei; Matsumoto, Kiyoshi; Tanaka, Hiroshi

    1999-05-01

    Long-term measurements of several trace gases and aerosols were carried out from December 1994 to October 1996 at Ogasawara Hahajima Island over the northwestern Pacific Ocean. The continental impact on the concentrations of sulfur compounds, ozone (O3), and cloud condensation nuclei (CCN) was estimated on the basis of the classification of air mass into seven types by isentropic trajectory analysis. From May to October, the air mass originating from the central North Pacific Ocean is predominant and regarded as the clean marine air for the concentrations of sulfur compounds and CCN. From the results of the molar ratio of methane sulfonic acid to non-sea-salt sulfate (NSS) and the positive correlation between dimethylsulfide (DMS) and CCN in this air mass it can be concluded that DMS largely contributes to the production of NSS and CCN. On the other hand, continental and anthropogenic substances are preferably transported to the northwestern Pacific Ocean by the predominant continental air mass from November to March. The enhancement of concentrations by the outflow from the Asian continent are estimated by a factor of 2.8 for O3, 3.9 for SO2, 3.5 for CCN activated at 0.5% supersaturation (0.5% CCN), 4.7 for 1.0% CCN, and 5.5 for NSS. Moreover, the CCN supersaturation spectra are also affected by the continental substances resulting in factor 2 of enhancement of cloud droplet number concentration. The diurnal variations of DMS and O3 for each air mass show a pattern of daytime minimum and nighttime maximum, which are typically found in remote ocean, even though those amplitudes are different for each air mass. Consequently, it can be concluded that the influence of nitric oxides (NOx) for the daytime O3 production and nitrate (NO3) radical for the nighttime oxidation of DMS are small even in the continental air mass.

  8. Cross-correlation Weak Lensing of SDSS Galaxy Clusters III: Mass-to-light Ratios

    SciTech Connect

    Sheldon, Erin S.; Johnston, David E.; Masjedi, Morad; McKay, Timothy A.; Blanton, Michael R.; Scranton, Ryan; Wechsler, Risa H.; Koester, Ben P.; Hansen, Sarah M.; Frieman, Joshua A.; Annis, James

    2007-09-28

    We present measurements of the excess mass-to-light ratio measured around MaxBCG galaxy clusters observed in the SDSS. This red sequence cluster sample includes objects from small groups with M{sub 200} {approx} 5 x 10{sup 12}h{sup -1}M{sub {circle_dot}} to clusters with M{sub 200} {approx} 5 x 10{sup 15}h{sup -1}M{sub {circle_dot}}. Using cross-correlation weak lensing, we measure the excess mass density profile above the universal mean {Delta}{yields}(r) = {rho}(r) -- {bar {rho}} for clusters in bins of richness and optical luminosity. We also measure the excess {sup 0.25}i-band luminosity density {Delta}{ell}(r) = {ell}(r) -- {bar {ell}}. For both mass and light, we de-project the profiles to produce 3D mass and light profiles over scales from 25h{sup -1} kpc to 22h{sup -1} Mpc. From these profiles we calculate the cumulative excess mass {Delta}M(r) and excess light {Delta}L(r) as a function of separation from the BCG. On small scales, where {rho}(r) >> {bar {rho}}, the integrated mass-to-light profile ({Delta}M/{Delta}L)(r) may be interpreted as the cluster mass-to-light ratio. We find the ({Delta}M/{Delta}L){sub 200}, the mass-to-light ratio within r{sub 200}, scales with cluster mass as a power law with index 0.33{+-}0.02. On large scales, where {rho}(r) {approx} {bar {rho}}, the {Delta}M/{Delta}L approaches an asymptotic value independent of scale or cluster richness. For small groups, the mean ({Delta}M/{Delta}L){sub 200} is much smaller than the asymptotic value, while for large clusters ({Delta}M/{Delta}L)200 is consistent with the asymptotic value. This asymptotic value should be proportional to the mean mass-to-light ratio of the universe {l_angle}M/L{r_angle}. We find {l_angle}M/L{r_angle} b{sup -2}{sub M/L} = 362 {+-} 54h measured in the {sup 0.25}i-bandpass. The parameter b{sup 2}{sub M/L} is primarily a function of the bias of the L {approx}< L* galaxies used as light tracers, and should be of order unity. Multiplying by the luminosity density in

  9. Algal layer ratios as indicators of air pollutant effects in Permelia sulcata

    USGS Publications Warehouse

    Bennett, J.P.

    2002-01-01

    Parmelia sulcata Taylor is generally believed to be fairly pollution tolerant, and consequently it is sometimes collected in urban and/or polluted localities. The condition of these specimens, however, is not always luxuriant and healthy. This study tested the hypothesis that total thallus and algal layer thickness, and the algal layer ratio would be thinner in polluted areas, thus allowing these characters to be used a indicators of air pollutant effects. Herbarium specimens were studied from 16 different localities varying in pollution level. The thallus and algal layers and ratio were not affected by year or locality of sampling, but decreased 11, 31 and 21% respectively between low and high pollution level localities. These results agreed with earlier studies using other species, but further work is needed to clarify the effects of geography and substrate on these phenomena.

  10. Evaluation of biological air filters for livestock ventilation air by membrane inlet mass spectrometry.

    PubMed

    Feilberg, Anders; Adamsen, Anders P S; Lindholst, Sabine; Lyngbye, Merete; Schäfer, Annette

    2010-01-01

    Biological air filters have been proposed as a cost-effective technology for reducing odor emissions from intensive swine production facilities. In this work we present results from the application of membrane inlet mass spectrometry (MIMS) for continuously monitoring the removal of odorous compounds in biological air filters. The sensitivity and selectivity were tested on synthetic samples of selected odorous compounds, and linearity and detection limits in the lower ppb range were demonstrated for all compounds tested (methanethiol, dimethyl sulfide, carboxylic acids, 4-methylphenol, aldehydes, indole, and skatole) except trimethylamine. The method was applied in situ at two full-scale filters installed at swine houses. The results have been compared with analyses by thermal desorption gas chromatography-mass spectrometry (TD-GC/MS), and odor was measured by olfactometry. By comparison with TD-GC/MS, observed MIMS signals were assigned to 4-methylphenol, 4-ethylphenol, indole, skatole, the sum of volatile reduced organic sulfur compounds (ROS), and three subgroups of carboxylic acids. The removal rates were observed to be related to air-water partitioning with removal efficiencies in the range of 0 to 50% for low-soluble organic sulfur compounds and high removal efficiencies (typically 80-100%) for more soluble phenols and carboxylic acids. Based on the results and published odor threshold values, it is estimated that the low removal efficiency of ROS is the main limitation for achieving a higher odor reduction. PMID:20400604

  11. Small-size mass spectrometer for determining gases and volatile compounds in air during breathing

    NASA Astrophysics Data System (ADS)

    Kogan, V. T.; Kozlenok, A. V.; Chichagov, Yu. V.; Antonov, A. S.; Lebedev, D. S.; Bogdanov, A. A.; Moroshkin, V. S.; Berezina, A. V.; Viktorova-Leclerc, O. S.; Vlasov, S. A.; Tubol'tsev, Yu. V.

    2015-10-01

    We describe an automated mass spectrometer for diagnostics of deceases from the composition of exhaled air. It includes a capillary system, which performs a rapid direct feeding of the sample to the instrument without changing substantially its composition and serves for studying the dynamics of variation of the ratio between various components of exhaled air. The membrane system for introducing the sample is intended for determining low concentrations of volatile organic compounds which are biomarkers of pathologies. It is characterized by selective transmittance and ensures the detection limits of target compounds at the parts per million-parts per billion (ppm-ppb) level. A static mass analyzer operating on permanent magnets possesses advantages important for mobile devices as compared to its dynamic analogs: it is more reliable in operation, has a larger dynamic range, and can be used for determining the concentration of components in the mixture one-by-one or simultaneously. The curvilinear output boundary of the magnetic lens of the mass analyzer makes it possible to reduce its weight and size by 2.5 times without deteriorating the mass resolution. We report on the results of testing of the instrument and consider the possibility of its application for early detection of deceases of respiratory and blood circulation system, gastrointestinal tract, and endocrine system.

  12. Study of the Tropospheric Aerosol Structure Under Changing of the Air Mass Type from Lidar Observations in Tomsk

    NASA Astrophysics Data System (ADS)

    Samoilova, S. V.; Balin, Yu. S.; Kokhanenko, G. P.; Penner, I. É.

    2016-04-01

    The aerosol optical characteristics in the main tropospheric layers are investigated based on joint interpretation of data of multi-frequency lidar sensing (110 sessions) and results of modeling of back air mass trajectories. Methodical problems for separating layers with different scattering properties and estimating their vertical boundaries are considered. Three optical criteria are simultaneously used to distinguish aerosol layers from cloud formations, including the gradient of the backscattering coefficient, optical depth, and the depolarization ratio. High values of the lidar ratio (66 sr) and of the Angstrom exponent (1.62) in the shortwavelength spectral range are observed in the boundary layer for Arctic transport. At the same time, low values of these optical parameters are characteristic for Asian transport: the lidar ratio is 54 sr and the Angstrom exponent is 1.1, which is explained by different relative contributions of the coarse and fine aerosol fractions to the air mass.

  13. Photometric Determination of Binary Mass Ratios in the WIYN Open Cluster Study (WOCS) Using Theoretical Isochrones

    NASA Astrophysics Data System (ADS)

    Cai, K.; Durisen, R. H.; Deliyannis, C. P.

    2003-05-01

    Binary stars in Galactic open clusters are difficult to detect without spectroscopic observations. However, from theoretical isochrones, we find that binary stars with different primary masses M1 and mass ratios q = M2/M1 have measurably different behaviors in various UBVRI color-magnitude and color-color diagrams. By using appropriate Yonsei-Yale Isochrones, in the best cases we can evaluate M1 and q to within about +/- 0.1Msun and +/- 0.1, respectively, for individual proper-motion members that have multiple WOCS UBVRI measurements of high quality. The cluster metallicity, reddening, and distance modulus and best-fit isochrones are determined self-consistently from the same WOCS data. This technique allows us to detect binaries and determine their mass ratios in open clusters without time-consuming spectrocopy, which is only sensitive to a limited range of binary separations. We will report results from this photometric technique for WOCS cluster M35 for M1 in the range of 1 to 4 Msun. For the lower main sequence, we used the empirical colors to reduce the error introduced by the problematic color transformations of Y2 Isochrones. In addition to other sources of uncertainty, we have considered effects of rapid rotation and pulsational instability. We plan to apply our method to other WOCS clusters in the future and explore differences in binary fractions and/or mass ratio distributions as a function of cluster age, metallicity, and other parameters.

  14. Development and Deployment of Retrofit PolarisQ Ion Trap Mass Spectrometer for Isotope Ratio Measurements

    SciTech Connect

    Thompson, Cyril V.; Whitten, William B.

    2015-11-01

    This report describes Oak Ridge National Laboratory’s (ORNL) FY15 progress in support of National Nuclear Security Administration’s (NNSA) Portable Mass Spectrometer project. A retrofit PolarisQ ion trap mass spectrometer (RPMS) has been assembled from components of two PolarisQ ion trap mass spectrometers used in previous isotope ratio programs. The retrofit mass spectrometer includes a custom Hastelloy vacuum chamber which is about ¼ the size of the standard aluminum vacuum chamber and reduces the instrument weight from the original by nine pounds. In addition, the new vacuum chamber can be independently heated to reduce impurities such as water, which reacts with UF6 to produce HF in the vacuum chamber. The analyzer and all components requiring service are mounted on the chamber lid, facilitating quick and easy replacement of consumable components such as the filament and electron multiplier.

  15. The Minimum Mass Ratio for Contact Close Binary Systems of W Ursae Majoris-Type

    NASA Astrophysics Data System (ADS)

    Arbutina, B.

    2012-12-01

    The main research topic of this dissertation are extreme mass ratio contact close binary systems, q ≲ 0.1, of W Ursae Majoris (W UMa) type. These close binaries (CBs) represent an interesting class of objects in which "normal", approximately one solar mass main-sequence star is in contact with a significantly less massive companion, M_2 ˜ 0.1 M_⊙. Earlier theoretical investigations of these systems found that there is a minimum mass ratio q_{min} = M_2/M_1 = 0.085 - 0.095 (obtained for n = 3 polytrope - fully radiative primary) above which these CBs are stable and could be observed. If the mass ratio is lower than q_{min}, or, equivalently, if orbital angular momentum is only about three times larger than the spin angular momentum of a massive primary, a tidal instability develops (Darwin's instability) forcing eventually the stars to merge into a single, rapidly rotating object (such as FK Com-type stars or blue stragglers). However, there appear to be some W UMa-type CBs with empirically obtained values for the mass ratio below the theoretical limit for stability. The aim of this dissertation is to try to resolve the discrepancy between theory and observations by considering rotating polytropes. By including in theory the effects of higher central condensation due to rotation we were able to reduce qmin to the new theoretical value q_{min} = 0.070-0.074, for the overcontact degree f = 0 - 1, which is more consistent with the observed population. Other candidate systems for stellar mergers such as AM CVn-type stars have also been discussed in the dissertation.

  16. High-Altitude Air Mass Zero Calibration of Solar Cells

    NASA Technical Reports Server (NTRS)

    Woodyard, James R.; Snyder, David B.

    2005-01-01

    Air mass zero calibration of solar cells has been carried out for several years by NASA Glenn Research Center using a Lear-25 aircraft and Langley plots. The calibration flights are carried out during early fall and late winter when the tropopause is at the lowest altitude. Measurements are made starting at about 50,000 feet and continue down to the tropopause. A joint NASA/Wayne State University program called Suntracker is underway to explore the use of weather balloon and communication technologies to characterize solar cells at elevations up to about 100 kft. The balloon flights are low-cost and can be carried out any time of the year. AMO solar cell characterization employing the mountaintop, aircraft and balloon methods are reviewed. Results of cell characterization with the Suntracker are reported and compared with the NASA Glenn Research Center aircraft method.

  17. Monitoring Trace Contaminants in Air Via Ion Trap Mass Spectrometry

    NASA Technical Reports Server (NTRS)

    Palmer, Peter T.; Karr, Dane; Pearson, Richard; Valero, Gustavo; Wong, Carla

    1995-01-01

    Recent passage of the Clean Air Act with its stricter regulation of toxic gas emissions, and the ever-growing number of applications which require faster turnaround times between sampling and analysis are two major factors which are helping to drive the development of new instrument technologies for in-situ, on-line, real-time monitoring. The ion trap, with its small size, excellent sensitivity, and tandem mass spectrometry capability is a rapidly evolving technology which is well-suited for these applications. In this paper, we describe the use of a commercial ion trap instrument for monitoring trace levels of chlorofluorocarbons (CFCs) and volatile organic compounds (VOCs) in air. A number of sample introduction devices including a direct transfer line interface, short column GC, and a cryotrapping interface are employed to achieve increasing levels of sensitivity. MS, MS/MS, and MS/MS/MS methods are compared to illustrate trade-offs between sensitivity and selectivity. Filtered Noise Field (FNF) technology is found to be an excellent means for achieving lower detection limits through selective storage of the ion(s) of interest during ionization. Figures of merit including typical sample sizes, detection limits, and response times are provided. The results indicate the potential of these techniques for atmospheric assessments, the High Speed Research Program, and advanced life support monitoring applications for NASA.

  18. Identification and Tracking of Polluted Air Masses in the South-Central Coast Air Basin.

    NASA Astrophysics Data System (ADS)

    Moore, G. E.; Douglas, S. G.; Kessler, R. C.; Killus, J. P.

    1991-05-01

    Canister samples of air taken during the South-Central Coast Cooperative Air Monitoring Program (SCCCAMP) 1985 field study program were analyzed for concentrations of over 50 hydrocarbons as well as chlorofluorocarbons (CFCs), carbon monoxide, hydrogen, and methane. Additional evidence of location and timing of airmass origin was obtained by utilizing long-lived halocarbons such as F-12 as `tracers of opportunity' in conjunction with known source profiles. Wind trajectories were developed from hourly gridded wind fields produced by a diagnostic wind model utilizing observed wind data. These wind trajectories were used to determine how pollutants from major source areas might be transported to sampling sites. Particulate lidar height-distance traverses were made from aircraft that provided a view of pollutant layering. Mixing height and vertical pollutant concentration distributions were obtained in order to determine if observed pollutant concentrations were consistent with the degree of stagnation present and hypothesized transport pathway.Analyses to track specific polluted air masses were conducted for the 13 September, 21 September, 23-24 September, and 2-3 October 1985 intensive study periods. The analyses find that elevated ozone concentrations during these periods are primarily attributed to transport and storage of ozone-enriched air from Los Angeles. During one type of episode (2-3 October) ozone and ozone precursors are stored near the surface over the Santa Barbara Channel overnight and transported into coastal areas on the following day. In another type of episode (23-24 September) ozone is transported into the study domain from the San Fernando Valley and Los Angeles via flow around the Santa Monica Hills. Transport of pollutant-enriched air takes place in a layer 200-500 m aloft, in many places overlaying cleaner marine-layer air. This advected ozone is mixed down to contribute to ground-level ozone concentrations over terrain where the marine layer

  19. ORBITAL AND MASS RATIO EVOLUTION OF PROTOBINARIES DRIVEN BY MAGNETIC BRAKING

    SciTech Connect

    Zhao, Bo; Li, Zhi-Yun

    2013-01-20

    The majority of stars reside in multiple systems, especially binaries. The formation and early evolution of binaries is a longstanding problem in star formation that is not yet fully understood. In particular, how the magnetic field observed in star-forming cores shapes the binary characteristics remains relatively unexplored. We demonstrate numerically, using an MHD version of the ENZO AMR hydro code, that a magnetic field of the observed strength can drastically change two of the basic quantities that characterize a binary system: the orbital separation and mass ratio of the two components. Our calculations focus on the protostellar mass accretion phase, after a pair of stellar 'seeds' have already formed. We find that in dense cores magnetized to a realistic level, the angular momentum of the material accreted by the protobinary is greatly reduced by magnetic braking. Accretion of strongly braked material shrinks the protobinary separation by a large factor compared to the non-magnetic case. The magnetic braking also changes the evolution of the mass ratio of unequal-mass protobinaries by producing material of low specific angular momentum that accretes preferentially onto the more massive primary star rather than the secondary. This is in contrast with the preferential mass accretion onto the secondary previously found numerically for protobinaries accreting from an unmagnetized envelope, which tends to drive the mass ratio toward unity. In addition, the magnetic field greatly modifies the morphology and dynamics of the protobinary accretion flow. It suppresses the traditional circumstellar and circumbinary disks that feed the protobinary in the non-magnetic case; the binary is fed instead by a fast collapsing pseudodisk whose rotation is strongly braked. The magnetic braking-driven inward migration of binaries from their birth locations may be constrained by high-resolution observations of the orbital distribution of deeply embedded protobinaries, especially

  20. An analytical system for stable isotope analysis on carbon monoxide using continuous-flow isotope-ratio mass spectrometry

    NASA Astrophysics Data System (ADS)

    Pathirana, S. L.; van der Veen, C.; Popa, M. E.; Röckmann, T.

    2015-12-01

    A fully automated system for the determination of δ13C and δ18O in atmospheric CO has been developed. CO is extracted from an air sample and converted into carbon dioxide (CO2) using the Schütze reagent. The isotopic composition is determined with an isotope-ratio mass spectrometer (IRMS) technique. The entire system is continuously flushed with high-purity helium (He), the carrier gas. The blank signal of the Schütze reagent is ~ 4 nmol mol-1, or 1-3 % of the typical sample size. The repeatability is 0.1 ‰ for δ13C and 0.2 ‰ for δ18O. The peak area allows for simultaneous determination of the mole fraction with an analytical repeatability of ~ 0.7 nmol mol-1 for 100 mL of ambient air (185.4 nmol mol-1 of CO). An automated single measurement is performed in only 18 min, and the achieved time efficiency (and small volume of sample air) allows for repetitive measurements practically.

  1. Improved isotope ratio measurement performance in liquid chromatography/isotope ratio mass spectrometry by removing excess oxygen.

    PubMed

    Hettmann, Elena; Brand, Willi A; Gleixner, Gerd

    2007-01-01

    A low dead volume oxygen scrubbing system was introduced in a commercially available liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) interface to enhance the analytical capability of the system. In the LC/IRMS interface carbon from organic samples is converted into CO(2) inside the mobile phase by wet chemical oxidation using peroxodisulfate (Na(2)S(2)O(8)). After passing the hot reaction zone, surplus oxygen (O(2)) remains dissolved in the liquid phase. Both CO(2) and O(2) diffuse through a transfer membrane into the helium carrier and are transferred to the mass spectrometer. The presence of O(2) in the ion source may have detrimental effects on measurement accuracy and precision as well as on filament lifetime. As a remedy, a new on-line O(2)-removing device has been incorporated into the system. The new O(2) scrubber consists of two parallel hot copper reduction reactors (0.8 mm i.d., active length 120 mm) and a switch-over valve between them. One reactor is regenerated using He/H(2) while the other is actively scavenging O(2) from the gas stream. The capacity of each reduction reactor, expressed as usage time, is between 40 and 50 min. This is sufficient for a single LC run for sugars and organic acids. A further increase of the reduction capacity is accompanied by a peak broadening of about 100%. After switching to a freshly reduced reactor the oxygen background and the delta(13)C values of the reference gas need up to 500 s to stabilize. For repeated injections the delta(13)C values of sucrose remain constant (+/-0.1 per thousand) for about 3000 s. The long-term stability for measurements of sucrose was 0.11 per thousand without the reduction oven and improved slightly to 0.08 per thousand with the reduction oven. The filament lifetime improved by more than 600%, thereby improving the long-term system stability and analytical efficiency. In addition the costs per analysis were reduced considerably. PMID:18041012

  2. Secondary ionization mass spectrometric analysis of impurity element isotope ratios in nuclear reactor materials

    NASA Astrophysics Data System (ADS)

    Gerlach, D. C.; Cliff, J. B.; Hurley, D. E.; Reid, B. D.; Little, W. W.; Meriwether, G. H.; Wickham, A. J.; Simmons, T. A.

    2006-07-01

    During reactor operations and fuel burn up, some isotopic abundances change due to nuclear reactions and provide sensitive indicators of neutron fluence and fuel burnup. Secondary ion mass spectrometry (SIMS) analysis has been used to measure isotope ratios of selected impurity elements in irradiated nuclear reactor graphite. Direct SIMS measurements were made in graphite samples, following shaping and surface cleaning. Models predicting local fuel burnup based on isotopic measurements of B and Li isotopes by SIMS agreed well with U and Pu isotopic measurements obtained by thermal ionization mass spectrometry (TIMS).

  3. Attribution of halo merger mass ratio and star formation rate density

    NASA Astrophysics Data System (ADS)

    Kim, Sungeun; Jo, Jeong-woon; Hwang, Jihe; Youn, Soyoung; Park, Boha

    2016-06-01

    We have used codes for implementing the merger tree algorithm by Cole et al. (2007) and Parkinson et al. (2008) and derived the halo merger mass ratio of protocluster of galaxies across the cosmic time. The authors compare the observed and simulated star formation rates reported by the various groups and derive the star formation rate densities at different red-shifts. This study implies that an investigation of different mass variables should be incorporated into the analysis in order to accurately estimate cumulative star formation rates of galaxies and star formation rate densities as a function of red-shifts.

  4. Probing Temperature from Intermediate Mass Fragment by Isobaric Yield Ratio in Heavy-Ion Collisions

    NASA Astrophysics Data System (ADS)

    Yu, Mian; Wei, Hui-Ling; Ma, Chun-Wang

    2015-12-01

    A probe to extract the temperature (TIYR) from intermediate-mass fragment has been proposed using the isobaric yield ratio (IYR) difference based on the modified Fisher model. By analyzing the isobaric cross section in the measured 140A MeV 40,48Ca+9Be reactions, the TIYR can well fit the IYR difference for the large mass fragments. Because of the fragments are produced in different colliding regions, it is also suggested to select the fragments according to different mechanisms when using TIYR. Supported by Program for Science & Technology Innovation Talents in Universities of Henan Province under Grant No. 13HASTIT046

  5. Measurement of M{sub w} using the transverse mass ratio of W and Z

    SciTech Connect

    Rajagopalan, S.; D0 Collaboration

    1996-11-01

    We report on the measurement of {ital W} boson mass from a direct determination of the ratio of the transverse masses of {ital W} and {ital Z} using the D{null} detector at the Fermilab Tevatron {ital p}{ital {anti p}} collider operating at {radical}s = 1.8 TeV. The analysis is a preliminary result based on a partial data sample of 13 {ital pb}{sup -1} using {ital W} {r_arrow} {ital e}{nu} and {ital Z} {r_arrow} {ital ee} decays.

  6. Organic Mass to Organic Carbon ratio in Atmospheric Aerosols: Observations and Global Simulations

    NASA Astrophysics Data System (ADS)

    Tsigaridis, K.; Kanakidou, M.; Daskalakis, N.

    2012-12-01

    Organic compounds play an important role in atmospheric chemistry and affect Earth's climate through their impact on oxidants and aerosol formation (e.g. O3 and organic aerosols (OA)). Due to the complexity of the mixture of organics in the atmosphere, the organic-mass-to-organic-carbon ratio (OM/OC) is often used to characterize the organic component in atmospheric aerosols. This ratio varies dependant on the aerosol origin and the chemical processing in the atmosphere. Atmospheric observations have shown that as OA and its precursor gases age in the atmosphere, it leads to the formation of more oxidized (O:C atomic ratio 0.6 to 0.8), less volatile and less hydrophobic compounds (particle growth factor at 95% relative humidity of 0.16 to 0.20) that have more similar properties than fresh aerosols. While reported OM:OC ratios observed over USA range between 1.29 and 1.95, indicating significant contribution of local pollution sources to the OC in that region, high O/C ratio associated with a high OM/OC ratio of 2.2 has been also observed for the summertime East Mediterranean aged aerosol. In global models, the OM/OC ratio is either calculated for specific compounds or estimated for compound groups. In the present study, we review OM/OC observations and compare them with simulations from a variety of models that contributed to the AEROCOM exercise. We evaluate the chemical processing level of atmospheric aerosols simulated by the models. A total of 32 global chemistry transport models are considered in this study with variable complexity of the representation of OM/OC ratio in the OA. The analysis provides an integrated view of the OM/OC ratio in the global atmosphere and of the accuracy of its representation in the global models. Implications for atmospheric chemistry and climate simulations are discussed.

  7. Binary star statistics - The mass ratio distribution for very wide systems

    NASA Astrophysics Data System (ADS)

    Trimble, V.

    Published observational data on a common-proper-motion sample (CPMS) of 326 pairs of AGK 3 stars (Halbwachs, 1986) with proper motion greater than 50 marcsec/yr and separation/proper-motion ratios less than 1000 yr are analyzed statistically to determine the frequency distribution of mass ratios (q = M2/M1). The results are presented in tables and graphs and compared with those for a sample of 798 visual binaries (VBs) studied by Worley and Heintz (1983). Both samples are found to have distributions with a peak at q = about 1, but this tendency is more pronounced in the VBs than in the CPMS. The q distribution of the VB sample, unlike that of the CPMS, cannot be explained by assuming that it is a random sample of normal initial mass functions; from this it is inferred that a binary formation mechanism which favors systems with q = about 1 may be involved.

  8. A first attempt to measure 92Nb/93Nb ratios with Accelerator Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Guozhu, He; Ming, He; Zuying, Zhou; Zhenyu, Li; Kejun, Dong; Shaoyong, Wu; Shilong, Liu; Xiongjun, Chen; Qiwen, Fan; Chaoli, Li; Xianwen, He; Heng, Li; Shan, Jiang

    2013-01-01

    An Accelerator Mass Spectrometry (AMS) method for the measurement of the long-lived radionuclide 92Nb has been established at the HI-13 Tandem Accelerator of the China Institute of Atomic Energy (CIAE). Niobium powder mixed with PbF2 by a ratio of 1:2 (in mass) was used as the cathode material. Atomic anions of Nb- were extracted from a Cs-beam sputter source. The terminal voltage of the tandem accelerator was 8.5 MV. Nb13+ ions were selected after terminal foil stripping. A multi-anode gas ionization chamber was used for the particle detection. The total suppression factor of the two major interfering isobars, 92Zr and 92Mo, was about 103. A detection limit of about 10-11 was achieved for 92Nb/93Nb ratio measurements on a blank sample.

  9. Formation of polyelectrolyte complexes with diethylaminoethyl dextran: charge ratio and molar mass effect.

    PubMed

    Le Cerf, Didier; Pepin, Anne Sophie; Niang, Pape Momar; Cristea, Mariana; Karakasyan-Dia, Carole; Picton, Luc

    2014-11-26

    The formation of polyelectrolyte complexes (PECs) between carboxymethyl pullulan and DEAE Dextran, was investigated, in dilute solution, with emphasis on the effect of charge density (molar ratio or pH) and molar masses. Electrophoretic mobility measurements have evidenced that insoluble PECs (neutral electrophoretic mobility) occurs for charge ratio between 0.6 (excess of polycation) and 1 (stoichiometry usual value) according to the pH. This atypical result is explained by the inaccessibility of some permanent cationic charge when screened by pH dependant cationic ones (due to the Hoffman alkylation). Isothermal titration calorimetry (ITC) indicates an endothermic formation of PEC with a binding constant around 10(5) L mol(-1). Finally asymmetrical flow field flow fractionation coupled on line with static multi angle light scattering (AF4/MALS) evidences soluble PECs with very large average molar masses and size around 100 nm, in agreement with scrambled eggs multi-association between various polyelectrolyte chains. PMID:25256478

  10. Effectiveness and humidification capacity investigation of liquid-to-air membrane energy exchanger under low heat capacity ratios at winter air conditions

    NASA Astrophysics Data System (ADS)

    Kassai, Miklos

    2015-06-01

    In this research, a novel small-scale single-panel liquid-to-air membrane energy exchanger has been used to numerically investigate the effect of given number of heat transfer units (4.5), different cold inlet air temperature (1.7, 5.0, 10.0 °C) and different low heat capacity ratio (0.4, 0.5, 0.6, 0.7, 0.8, 0.9) on the steady-state performance of the energy exchanger. This small-scale energy exchanger represents the full-scale prototypes well, saving manufacturing costs and time. Lithium chloride is used as a salt solution in the system and the steady-state total effectiveness of the exchanger is evaluated for winter inlet air conditions. The results show that total effectiveness of the energy exchanger decreases with heat capacity ratio in the mentioned range. Maximum numerical total effectiveness of 97% is achieved for the energy exchanger. Increasing the heat capacity ratio values on given inlet air temperature, the humidification capacity of energy exhanger is also investigated in this paper. The humidification performance increases with heat capacity ratio. The highest humidification performance (4.53 g/kg) can be reached when inlet air temperature is 1.7 °C, and heat capacity ratio is 1.0 in winter inlet air conditions in the range of low heat capacity ratio.

  11. Impact of left ventricular volume/mass ratio on diastolic function

    PubMed Central

    Buakhamsri, Adisai; Popović, Zoran B.; Lin, Jingna; Lim, Pascal; Greenberg, Neil L.; Borowski, Allen G.; Tang, W.H. Wilson; Klein, Allan L.; Lever, Harry M.; Desai, Milind Y.; Thomas, James D.

    2009-01-01

    Aims To assess the impact of left ventricular (LV) volume/mass ratio on diastolic function parameters in subjects with dilated cardiomyopathy (DCM) or hypertrophic cardiomyopathy (HCM) and healthy controls. Methods and results We performed echocardiography in 44 healthy controls, 35 HCM subjects, 29 DCM subjects with narrow QRS complex (DCM-n), and 27 DCM subjects with wide QRS complex (DCM-w). Mitral annulus velocity (Ea) and transmitral E-wave velocity were used to estimate time constant of isovolumic pressure decay (τ). LV flow propagation velocity (Vp) and early intraventricular pressure gradient (IVPG) were derived from colour M-mode of LV inflow. We calculated LV twist and peak untwisting rate (UntwR) by speckle tracking. Mean LV volume/mass ratio was 0.34 ± 0.09 mL/g in healthy controls, 0.15 ± 0.06 mL/g in HCM, 0.6 ± 0.2 mL/g in DCM-n, and 0.8 ± 0.3 mL/g in DCM-w patients (P < 0.001 for all groups). Resting LV ejection fractions were 63 ± 7, 64 ± 8, 31 ± 8, and 26 ± 8%, respectively (P < 0.01 vs. controls for DCM groups). In a multivariate analysis, LV volume/mass ratio remained a strong independent predictor of Vp (P < 0.001), IVPG (P = 0.009), and UntwR (P < 0.001) but not for Ea (P = 0.25). Conclusion LV volume/mass ratio had influences on diastolic function parameters independent of intrinsic diastolic function and filling pressures. It should be considered when assessing patients suspected of LV diastolic dysfunction. PMID:19304742

  12. The very short-period extreme mass ratio binary 75 Pegasi - Photometry and model

    SciTech Connect

    Martin, B.E.; Hube, D.P.; Brown, C. Alberta, University, Edmonton Glenlea Astronomical Observatory Manitoba, University, Winnipeg )

    1991-05-01

    The bright star 75 Peg is a close binary ellipsoidal variable with a short period (0.5021035-day) and an extreme mass ratio of 0.104 B, V, and R photometric data, along with previously published radial-velocity data, are analyzed; they suggest that the primary of the 75 Peg system may be, or is very close to, filling its critical Roche lobe. 11 refs.

  13. Evaluating chlorine isotope effects from isotope ratios and mass spectra of polychlorinated molecules.

    PubMed

    Elsner, Martin; Hunkeler, Daniel

    2008-06-15

    Compound-specific chlorine isotope analysis receives much interest to assess the fate of chlorinated hydrocarbons in contaminated environments. This paper provides a theoretical basis to calculate isotope ratios and quantify isotope fractionation from ion-current ratios of molecular- and fragment-ion multiplets. Because both (35)Cl and (37)Cl are of high abundance, polychlorinated hydrocarbons consist of molecules containing different numbers of (37)Cl denoted as isotopologues. We show that, during reactions, the changes in isotopologue ratios are proportional to changes in the isotope ratio assuming a nonselective isotope distribution in the initial compound. This proportionality extents even to fragments formed in the ion source of a mass spectrometer such as C 2Cl 2 (double dechlorinated fragment of perchloroethylene, PCE). Fractionation factors and kinetic isotope effects (KIE) may, therefore, be evaluated from isotope, isotopologue or even fragment ratios according to conventional simple equations. The proportionality is exact with symmetric molecules such as dichloroethylene (DCE) and PCE, whereas it is approximately true with molecules containing nonreactive positions such as trichloroethylene (TCE). If in the latter case isotope ratios are derived from dechlorinated fragments, e.g., C 2HCl 2, it is important that fragmentation in the ion source affect all molecular positions alike, as otherwise isotopic changes in reactive positions may be underrepresented. PMID:18484745

  14. Accuracy of delta 18O isotope ratio measurements on the same sample by continuous-flow isotope-ratio mass spectrometry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The doubly labeled water method is considered the reference method to measure energy expenditure. Conventional mass spectrometry requires a separate aliquot of the same sample to be prepared and analyzed separately. With continuous-flow isotope-ratio mass spectrometry, the same sample could be analy...

  15. New GUT predictions for quark and lepton mass ratios confronted with phenomenology

    SciTech Connect

    Antusch, S.; Spinrath, M.

    2009-05-01

    Group theoretical factors from grand unified theory (GUT) symmetry breaking can lead to predictions for the ratios of quark and lepton masses (or Yukawa couplings) at the unification scale. Because of supersymmetric (SUSY) threshold corrections the viability of such predictions can depend strongly on the SUSY parameters. For three common minimal SUSY breaking scenarios with anomaly, gauge, and gravity mediation we investigate which GUT scale ratios m{sub e}/m{sub d}, m{sub {mu}}/m{sub s}, y{sub {tau}}/y{sub b}, and y{sub t}/y{sub b} are allowed when phenomenological constraints from electroweak precision observables, B physics, (g-2){sub {mu}}, mass limits on sparticles from direct searches as well as, optionally, dark matter constraints are taken into account. We derive possible new predictions for the GUT scale mass ratios and compare them with the phenomenologically allowed ranges. We find that new GUT scale predictions such as m{sub {mu}}/m{sub s}=9/2 or 6 and y{sub {tau}}/y{sub b}=3/2 or 2 are often favored compared to the ubiquitous relations m{sub {mu}}/m{sub s}=3 or y{sub {tau}}/y{sub b}=1. They are viable for characteristic SUSY scenarios, testable at the CERN LHC and future colliders.

  16. Effective-one-body model for black-hole binaries with generic mass ratios and spins

    NASA Astrophysics Data System (ADS)

    Taracchini, Andrea; Buonanno, Alessandra; Pan, Yi; Hinderer, Tanja; Boyle, Michael; Hemberger, Daniel A.; Kidder, Lawrence E.; Lovelace, Geoffrey; Mroué, Abdul H.; Pfeiffer, Harald P.; Scheel, Mark A.; Szilágyi, Béla; Taylor, Nicholas W.; Zenginoglu, Anil

    2014-03-01

    Gravitational waves emitted by black-hole binary systems have the highest signal-to-noise ratio in LIGO and Virgo detectors when black-hole spins are aligned with the orbital angular momentum and extremal. For such systems, we extend the effective-one-body inspiral-merger-ringdown waveforms to generic mass ratios and spins calibrating them to 38 numerical-relativity nonprecessing waveforms produced by the SXS Collaboration. The numerical-relativity simulations span mass ratios from 1 to 8, spin magnitudes up to 98% of extremality, and last for 40 to 60 gravitational-wave cycles. When the total mass of the binary is between 20 and 200M⊙, the effective-one-body nonprecessing (dominant mode) waveforms have overlap above 99% (using the advanced-LIGO design noise spectral density) with all of the 38 nonprecessing numerical waveforms, when maximizing only on initial phase and time. This implies a negligible loss in event rate due to modeling. We also show that—without further calibration— the precessing effective-one-body (dominant mode) waveforms have overlap above 97% with two very long, strongly precessing numerical-relativity waveforms, when maximizing only on the initial phase and time.

  17. Estimation of bone Calcium-to-Phosphorous mass ratio using dual-energy nonlinear polynomial functions

    NASA Astrophysics Data System (ADS)

    Sotiropoulou, P.; Koukou, V.; Martini, N.; Michail, C.; Kounadi, E.; Kandarakis, I.; Nikiforidis, G.; Fountos, G.

    2015-09-01

    In this study an analytical approximation of dual-energy inverse functions is presented for the estimation of the calcium-to-phosphorous (Ca/P) mass ratio, which is a crucial parameter in bone health. Bone quality could be examined by the X-ray dual-energy method (XDEM), in terms of bone tissue material properties. Low- and high-energy, log- intensity measurements were combined by using a nonlinear function, to cancel out the soft tissue structures and generate the dual energy bone Ca/P mass ratio. The dual-energy simulated data were obtained using variable Ca and PO4 thicknesses on a fixed total tissue thickness. The XDEM simulations were based on a bone phantom. Inverse fitting functions with least-squares estimation were used to obtain the fitting coefficients and to calculate the thickness of each material. The examined inverse mapping functions were linear, quadratic, and cubic. For every thickness, the nonlinear quadratic function provided the optimal fitting accuracy while requiring relative few terms. The dual-energy method, simulated in this work could be used to quantify bone Ca/P mass ratio with photon-counting detectors.

  18. Accuracy of Linear Depolarisation Ratios in Clean Air Ranges Measured with POLIS-6 at 355 and 532 NM

    NASA Astrophysics Data System (ADS)

    Freudenthaler, Volker; Seefeldner, Meinhard; Groß, Silke; Wandinger, Ulla

    2016-06-01

    Linear depolarization ratios in clean air ranges were measured with POLIS-6 at 355 and 532 nm. The mean deviation from the theoretical values, including the rotational Raman lines within the filter bandwidths, amounts to 0.0005 at 355 nm and to 0.0012 at 532 nm. The mean uncertainty of the measured linear depolarization ratio of clean air is about 0.0005 at 355 nm and about 0.0006 at 532 nm.

  19. The use of gas chromatography-mass spectrometry/combustion/isotope ratio mass spectrometry to demonstrate progesterone treatment in bovines.

    PubMed

    Janssens, Geert; Mangelinckx, Sven; Courtheyn, Dirk; De Kimpe, Norbert; Matthijs, Bert; Le Bizec, Bruno

    2016-06-01

    Currently, no analytical method is available to demonstrate progesterone administration in biological samples collected in rearing animals, and therefore, tracking the abuse of this popular growth promoter is arduous. In this study, a method is presented to reveal progesterone (PG) treatment on the basis of carbon isotope measurement of 5β-pregnane-3α, 20α-diol (BAA-PD), a major PG metabolite excreted in bovine urine, by gas chromatography-mass spectrometry/combustion/isotope ratio mass spectrometry (GC-MS/C/IRMS). 5-Androstene-3β,17α-diol (AEdiol) is used as endogenous reference compound. Intermediate precisions (n=11) of 0.56‰ and 0.68‰ have been determined for AEdiol and BAA-PD, respectively. The analytical method was used for the very first time to successfully differentiate urine samples collected in treated and untreated animals. PMID:27157423

  20. Osmium isotopic ratio measurements by inductively coupled plasma source mass spectrometry

    SciTech Connect

    Russ, G.P. III; Bazan, J.M.; Date, A.R.

    1987-04-01

    The isotopic composition of nanogram quantities of osmium was measured by using an inductively coupled plasma source mass spectrometer. Sensitivity was enhanced a factor of approx.100 by the use of an osmium tetraoxide vapor generator rather than nebulization of solution. For samples less than or equal to5 ng, the ratios /sup 190/Os//sup 192/Os, /sup 189/Os//sup 192/Os, and /sup 188/Os//sup 192/Os were determined to better than +/- 0.5% (1sigma/sub m/) precision. For the minor isotopes, the ratios /sup 187/Os//sup 192/Os and /sup 186/Os//sup 192/Os were determined to +/-1%, and /sup 184/Os//sup 192/Os (4 x 10/sup -4/) was determined to approx.10%. Isotope ratios for common osmium are reported.

  1. Determination of phenylalanine isotope ratio enrichment by liquid chromatography/time- of-flight mass spectrometry.

    PubMed

    Wu, Zhanpin; Zhang, Xiao-Jun; Cody, Robert B; Wolfe, Robert R

    2004-01-01

    The application of time-of-flight mass spectrometry to isotope ratio measurements has been limited by the relatively low dynamic range of the time-to-digital converter detectors available on commercial LC/ToF-MS systems. Here we report the measurement of phenylalanine isotope ratio enrichment by using a new LC/ToF-MS system with wide dynamic range. Underivatized phenylalanine was injected onto a C18 column directly with 0.1% formic acid/acetonitrile as the mobile phase. The optimal instrument parameters for the time-of-flight mass spectrometer were determined by tuning the instrument with a phenylalanine standard. The accuracy of the isotope enrichment measurement was determined by the injection of standard solutions with known isotope ratios ranging from 0.02% to 9.2%. A plot of the results against the theoretical values gave a linear curve with R2 of 0.9999. The coefficient of variation for the isotope ratio measurement was below 2%. The method is simple, rapid, and accurate and presents an attractive alternative to traditional GC/MS applications. PMID:15531795

  2. Isotope ratio mass spectrometry coupled to liquid and gas chromatography for wine ethanol characterization.

    PubMed

    Cabañero, Ana I; Recio, Jose L; Rupérez, Mercedes

    2008-10-01

    Two new procedures for wine ethanol 13C/12C isotope ratio determination, using high-performance liquid chromatography and gas chromatography isotope ratio mass spectrometry (HPLC/IRMS and GC/IRMS), have been developed to improve isotopic methods dedicated to the study of wine authenticity. Parameters influencing separation of ethanol from wine matrix such as column, temperature, mobile phase, flow rates and injection mode were investigated. Twenty-three wine samples from various origins were analyzed for validation of the procedures. The analytical precision was better than 0.15 per thousand, and no significant isotopic fractionation was observed employing both separative techniques coupled to IRMS. No significant differences and a very strong correlation (r = 0.99) were observed between the 13C/12C ratios obtained by the official method (elemental analyzer/isotope ratio mass spectrometry) and the proposed new methodology. The potential advantages of the developed methods over the traditional one are speed (reducing time required from hours to minutes) and simplicity. In addition, these are the first isotopic methods that allow 13C/12C determination directly from a liquid sample with no previous ethanol isolation, overcoming technical difficulties associated with sample treatment. PMID:18798196

  3. Prospects for detection of gravitational waves from intermediate-mass-ratio inspirals.

    PubMed

    Brown, Duncan A; Brink, Jeandrew; Fang, Hua; Gair, Jonathan R; Li, Chao; Lovelace, Geoffrey; Mandel, Ilya; Thorne, Kip S

    2007-11-16

    We explore prospects for detecting gravitational waves from stellar-mass compact objects spiraling into intermediate mass black holes (BHs) M approximately 50M to 350M) with ground-based observatories. We estimate a rate for such intermediate-mass-ratio inspirals of

  4. Influence of the overfire air ratio on the NO(x) emission and combustion characteristics of a down-fired 300-MW(e) utility boiler.

    PubMed

    Ren, Feng; Li, Zhengqi; Chen, Zhichao; Fan, Subo; Liu, Guangkui

    2010-08-15

    Down-fired boilers used to burn low-volatile coals have high NO(x) emissions. To find a way of solving this problem, an overfire air (OFA) system was introduced on a 300 MW(e) down-fired boiler. Full-scale experiments were performed on this retrofitted boiler to explore the influence of the OFA ratio (the mass flux ratio of OFA to the total combustion air) on the combustion and NO(x) emission characteristics in the furnace. Measurements were taken of gas temperature distributions along the primary air and coal mixture flows, average gas temperatures along the furnace height, concentrations of gases such as O(2), CO, and NO(x) in the near-wall region and carbon content in the fly ash. Data were compared for five different OFA ratios. The results show that as the OFA ratio increases from 12% to 35%, the NO(x) emission decreases from 1308 to 966 mg/Nm(3) (at 6% O(2) dry) and the carbon content in the fly ash increases from 6.53% to 15.86%. Considering both the environmental and economic effect, 25% was chosen as the optimized OFA ratio. PMID:20666359

  5. Effect of Fuel-Air Ratio, Inlet Temperature, and Exhaust Pressure on Detonation

    NASA Technical Reports Server (NTRS)

    Taylor, E S; Leary, W A; Diver, J R

    1940-01-01

    An accurate determination of the end-gas condition was attempted by applying a refined method of analysis to experimental results. The results are compared with those obtained in Technical Report no. 655. The experimental technique employed afforded excellent control over the engine variables and unusual cyclic reproducibility. This, in conjunction with the new analysis, made possible the determination of the state of the end-gas at any instant to a fair degree of precision. Results showed that for any given maximum pressure the maximum permissible end-gas temperature increased as the fuel-air ratio was increased. The tendency to detonate was slightly reduced by an increase in residual gas content resulting from an increase in exhaust backpressure with inlet pressure constant.

  6. Mass transfer of VOCs in laboratory-scale air sparging tank.

    PubMed

    Chao, Keh-Ping; Ong, Say Kee; Huang, Mei-Chuan

    2008-04-15

    Volatilization of VOCs was investigated using a 55-gal laboratory-scale model in which air sparging experiments were conducted with a vertical air injection well. In addition, X-ray imaging of an air sparging sand box showed air flows were in the form of air bubbles or channels depending on the size of the porous media. Air-water mass transfer was quantified using the air-water mass transfer coefficient which was determined by fitting the experimental data to a two-zone model. The two-zone model is a one-dimensional lumped model that accounts for the effects of air flow type and diffusion of VOCs in the aqueous phase. The experimental air-water mass transfer coefficients, KGa, obtained from this study ranged from 10(-2) to 10(-3)1/min. From a correlation analysis, the air-water mass transfer coefficient was found to be directly proportional to the air flow rate and the mean particle size of soil but inversely proportional to Henry's constant. The correlation results implied that the air-water mass transfer coefficient was strongly affected by the size of porous media and the air flow rates. PMID:17804158

  7. Preoperative body mass index-to-prognostic nutritional index ratio predicts pancreatic fistula after pancreaticoduodenectomy

    PubMed Central

    Tamura, Toshihisa; Minagawa, Noritaka; Hirata, Keiji

    2016-01-01

    Background Estimating or scoring the risk of post-operative pancreatic fistula (POPF) may help with selection of high-risk patients and individualized patient consent. However, there are no simple and reliable preoperative predictors of POPF used in daily clinical practice. Methods We investigated the utility of body mass index-to-prognostic nutritional index (BMI/PNI) ratio as a preoperative marker to predict the development of POPF in 87 patients undergoing pancreaticoduodenectomy. Results The overall incidence of clinical (grade B/C) POPF was 17% (15 of 87 patients). Among various pre-, intra-, and post-operative variables analyzed, higher BMI and lower PNI were identified as independent predictors for POPF by multivariate analysis. We therefore investigated BMI/PNI ratio as a preoperative predictor for POPF. BMI/PNI ratio was significantly higher in patients with POPF than in those without POPF (0.54 vs. 0.45, P=0.0007). A receiver operating characteristic (ROC) curve analysis demonstrated a fair capability of BMI/PNI ratio to predict the occurrence of POPF (area under the ROC curve 0.781). With a cut-off value of 0.5, the sensitivity, specificity, and diagnostic accuracy of BMI/PNI ratio to predict POPF was 73%, 74%, and 74%, respectively. In particular, when restricted to a subgroup of elderly (≥75 years old) male patients, the sensitivity, specificity, and diagnostic accuracy of BMI/PNI ratio was 100%, 100%, and 100%, respectively. Conclusions The BMI/PNI ratio is a simple preoperative marker to predict the occurrence of POPF after pancreaticoduodenectomy. PMID:27275468

  8. Association of fat to lean mass ratio with metabolic dysfunction in women with polycystic ovary syndrome

    PubMed Central

    Ezeh, Uche; Pall, Marita; Mathur, Ruchi; Azziz, Ricardo

    2014-01-01

    STUDY QUESTION Are differences in metabolic dysfunction between polycystic ovary syndrome (PCOS) and control women related to differences in their fat to lean mass (F/L) ratio? SUMMARY ANSWER Compared with controls of similar body mass index (BMI), women with PCOS demonstrate adverse body composition characterized by increased whole body fat relative to lean mass (i.e. a higher F/L ratio), which is associated with differences in metabolic dysfunction between the two groups. WHAT IS KNOWN ALREADY Previous studies examining body composition and insulin resistance (IR) in PCOS have yielded conflicting results. Excess total fat mass (i.e. fat mass index [fat BMI]) correlates with IR, whereas increased total lean mass (i.e. lean BMI) has been associated with higher insulin sensitivity. However, the role of the F/L ratio, which integrates the antagonistic effects of both fat and lean mass depots, on IR in PCOS, has not been investigated. STUDY DESIGN, SIZE, DURATION We conducted a prospective cross-sectional study of 120 women between the ages of 22–44 years to study the relation of the F/L ratio with measures of insulin action and secretion in both steady and dynamic states. PARTICIPANTS/MATERIALS, SETTING, METHODS Sixty PCOS (by NIH, 1990 criteria) and 60 control (age, race and BMI-matched) women were prospectively studied for body composition (by bioelectrical impedance analysis [BIA]) and basal IR and insulin secretion by the homeostasis model assessment (HOMA-IR and HOMA-%β-cell function, respectively) in a tertiary care academic referral center. A subset of 12 PCOS and 12 matched control women also underwent a modified frequently sampled intravenous glucose tolerance test (FSIVGTT) to determine glucose uptake and insulin secretion in dynamic state. MAIN RESULTS AND THE ROLE OF CHANCE Our results indicate that women with PCOS demonstrated greater degrees of hyperandrogenism, and higher waist-to-hip ratio (WHR), %body fat, fat BMI, F/L, fasting insulin levels, and

  9. Mid-infrared-selected quasars. I. Virial black hole mass and eddington ratios

    SciTech Connect

    Dai, Y. Sophia; Elvis, Martin; Fazio, Giovanni G.; Huang, Jia-Sheng; Wilkes, Belinda J.; Bergeron, Jacqueline; Omont, Alain; Willmer, Christopher N. A.; Papovich, Casey

    2014-08-20

    We provide a catalog of 391 mid-infrared-selected (MIR; 24 μm) broad-emission-line (BEL; type 1) quasars in the 22 deg{sup 2} SWIRE Lockman Hole field. This quasar sample is selected in the MIR from Spitzer MIPS with S {sub 24} > 400 μJy, jointly with an optical magnitude limit of r (AB) < 22.5 for broad line identification. The catalog is based on MMT and Sloan Digital Sky Survey (SDSS) spectroscopy to select BEL quasars, extending the SDSS coverage to fainter magnitudes and lower redshifts, and recovers a more complete quasar population. The MIR-selected quasar sample peaks at z ∼ 1.4 and recovers a significant and constant (20%) fraction of extended objects with SDSS photometry across magnitudes, which were not included in the SDSS quasar survey dominated by point sources. This sample also recovers a significant population of z < 3 quasars at i > 19.1. We then investigate the continuum luminosity and line profiles of these MIR quasars, and estimate their virial black hole masses and the Eddington ratios. The supermassive black hole mass shows evidence of downsizing, although the Eddington ratios remain constant at 1 < z < 4. Compared to point sources in the same redshift range, extended sources at z < 1 show systematically lower Eddington ratios. The catalog and spectra are publicly available online.

  10. Poiseuille flow-induced vibrations of two tandem circular cylinders with different mass ratios

    NASA Astrophysics Data System (ADS)

    Jiang, Ren-Jie; Lin, Jian-Zhong

    2016-06-01

    Flow-induced vibrations of two tandem circular cylinders with different mass ratios confined between two parallel walls are numerically studied via a lattice Boltzmann method. With fixed Reynolds number Re = 100 and blockage ratio β = 1/4, the effects of mass ratio m* = [0.0625, 16] and streamwise separation between two cylinders S/D = [1.125, 10] on the cylinder motions and vortex wake modes are investigated. A variety of distinct cylinder motion regimes involving the symmetric periodic vibration, biased quasi-periodic vibration, beating vibration, and steady regimes, with the corresponding wake structures, e.g., two rows of alternately rotating vortices, a single row of same-sign vortices, and steady wake, are observed. For each current case, the cylinder motion type is exclusive and in the binary oscillation regime, both cylinders always vibrate at a common primary frequency. The lighter cylinder usually oscillates at a larger amplitude than the heavier one, while the heavier cylinder undergoes larger lift force than the lighter one. The lift force and cylinder displacement always behave as an out-of-phase state. In the gap-interference region, large-amplitude oscillations could be produced extensively and in the wake-interference region, the cylinder motions and fluid flows are mainly dependent on the upstream cylinder. When the separation is large enough, both cylinders behave as two isolated ones. The mechanisms for the excitations of cylinder vibrations have also been analysed.

  11. Mid-infrared-selected Quasars. I. Virial Black Hole Mass and Eddington Ratios

    NASA Astrophysics Data System (ADS)

    Dai, Y. Sophia; Elvis, Martin; Bergeron, Jacqueline; Fazio, Giovanni G.; Huang, Jia-Sheng; Wilkes, Belinda J.; Willmer, Christopher N. A.; Omont, Alain; Papovich, Casey

    2014-08-01

    We provide a catalog of 391 mid-infrared-selected (MIR; 24 μm) broad-emission-line (BEL; type 1) quasars in the 22 deg2 SWIRE Lockman Hole field. This quasar sample is selected in the MIR from Spitzer MIPS with S 24 > 400 μJy, jointly with an optical magnitude limit of r (AB) < 22.5 for broad line identification. The catalog is based on MMT and Sloan Digital Sky Survey (SDSS) spectroscopy to select BEL quasars, extending the SDSS coverage to fainter magnitudes and lower redshifts, and recovers a more complete quasar population. The MIR-selected quasar sample peaks at z ~ 1.4 and recovers a significant and constant (20%) fraction of extended objects with SDSS photometry across magnitudes, which were not included in the SDSS quasar survey dominated by point sources. This sample also recovers a significant population of z < 3 quasars at i > 19.1. We then investigate the continuum luminosity and line profiles of these MIR quasars, and estimate their virial black hole masses and the Eddington ratios. The supermassive black hole mass shows evidence of downsizing, although the Eddington ratios remain constant at 1 < z < 4. Compared to point sources in the same redshift range, extended sources at z < 1 show systematically lower Eddington ratios. The catalog and spectra are publicly available online. Observations reported here were obtained at the MMT Observatory, a joint facility of the Smithsonian Institution and the University of Arizona.

  12. Nitrogen isotopic analyses by isotope-ratio-monitoring gas chromatography/mass spectrometry

    NASA Technical Reports Server (NTRS)

    Merritt, D. A.; Hayes, J. M.

    1994-01-01

    Amino acids containing natural-abundance levels of 15N were derivatized and analyzed isotopically using a technique in which individual compounds are separated by gas chromatography, combusted on-line, and the product stream sent directly to an isotope-ratio mass spectrometer. For samples of N2 gas, standard deviations of ratio measurement were better than 0.1% (Units for delta are parts per thousand or per million (%).) for samples larger than 400 pmol and better than 0.5% for samples larger than 25 pmol (0.1% 15N is equivalent to 0.00004 atom % 15N). Results duplicated those of conventional, batchwise analyses to within 0.05%. For combustion of organic compounds yielding CO2/N2 ratios between 14 and 28, in particular for N-acetyl n-propyl derivatives of amino acids, delta values were within 0.25% of results obtained using conventional techniques and standard deviations were better than 0.35%. Pooled data for measurements of all amino acids produced an accuracy and precision of 0.04 and 0.23%, respectively, when 2 nmol of each amino acid was injected on column and 20% of the stream of combustion products was delivered to the mass spectrometer.

  13. Back-casting sociality in extinct species: new perspectives using mass death assemblages and sex ratios.

    PubMed Central

    Berger, J; Dulamtseren, S; Cain, S; Enkkhbileg, D; Lichtman, P; Namshir, Z; Wingard, G; Reading, R

    2001-01-01

    Despite 150 years of interest in the ecology of dinosaurs, mammoths, proto-hominids and other extinct vertebrates, a general framework to recreate patterns of sociality has been elusive. Based on our recent discovery of a contemporary heterospecific mass death assemblage in the Gobi Desert (Mongolia), we fit predictions about gender-specific associations and group living in extant ungulates to extinct ones. We relied on comparative data on sex-ratio variation and body-size dimorphism, basing analyses on 38 additional mass mortality sites from Asia, Africa, Europe and North America that span 50 million years. Both extant and extinct species died in aggregations with biased adult sex ratios, but the skew (from 1:1) was greater for extinct dimorphic taxa, suggesting that sociality in these extinct species can be predicted from spatial and demographic traits of extant ones. However, extinct rhinos, horses and zebras were inconsistent with predictions about adult sex ratios, which underscores the inherent difficulty in backcasting historic patterns to some monomorphic taxa. These findings shed light not only on the sociality of extinct species but provide a sound, although limited, footing for interpretation of modern death assemblages within the context of the emerging science of taphonomy and palaeobehaviour. PMID:11209882

  14. Abundance ratios of red giants in low-mass ultra-faint dwarf spheroidal galaxies

    NASA Astrophysics Data System (ADS)

    François, P.; Monaco, L.; Bonifacio, P.; Moni Bidin, C.; Geisler, D.; Sbordone, L.

    2016-04-01

    Context. Low-mass dwarf spheroidal galaxies are key objects for our understanding of the chemical evolution of the pristine Universe and the Local Group of galaxies. Abundance ratios in stars of these objects can be used to better understand their star formation and chemical evolution. Aims: We report on the analysis of a sample of 11 stars belonging to five different ultra-faint dwarf spheroidal galaxies (UfDSph) that is based on X-Shooter spectra obtained at the VLT. Methods: Medium-resolution spectra have been used to determine the detailed chemical composition of their atmosphere. We performed a standard 1D LTE analysis to compute the abundances. Results: Considering all the stars as representative of the same population of low-mass galaxies, we found that the [α/Fe] ratios vs.s [Fe/H] decreases as the metallicity of the star increases in a way similar to that which is found for the population of stars that belong to dwarf spheroidal galaxies. The main difference is that the solar [α/Fe] is reached at a much lower metallicity for the UfDSph than for the dwarf spheroidal galaxies. We report for the first time the abundance of strontium in CVn II. The star we analyzed in this galaxy has a very high [Sr/Fe] and a very low upper limit of barium which makes it a star with an exceptionally high [Sr/Ba] ratio.

  15. Variability in the O{sub 2}/N{sub 2} ratio of southern hemisphere air, 1991-1994: Implications for the carbon cycle

    SciTech Connect

    Bender, M.; Ellis, T.; Tans, P.

    1996-03-01

    The oxygen/nitrogen ratio of air was measured from 1991 to 1994 and analyzed for trends attributable to fossil fuel combustion and decreasing biosphere. Mass spectrometric analysis of flask samples from Tasmania and Greenland was used for the study. The data showed the expected seasonal variations and a trend of decreasing oxygen concentration. Anthropogenic carbon fluxes calculated from the data are presented. The oxygen/nitrogen ratio of air decreased at the rate of 12 {plus_minus} 4 per meg per year from winter 1991 and winter 1993. The oxygen consumption rate for fossil fuel burning is estimated at 20 per meg per year. This suggests that either the land biosphere was an oxygen source and carbon dioxide sink during this period, or the oceans were a transient oxygen sink. 26 refs., 3 figs., 7 tabs.

  16. Direct isotope ratio analysis of individual uranium-plutonium mixed particles with various U/Pu ratios by thermal ionization mass spectrometry.

    PubMed

    Suzuki, Daisuke; Esaka, Fumitaka; Miyamoto, Yutaka; Magara, Masaaki

    2015-02-01

    Uranium and plutonium isotope ratios in individual uranium-plutonium (U-Pu) mixed particles with various U/Pu atomic ratios were analyzed without prior chemical separation by thermal ionization mass spectrometry (TIMS). Prior to measurement, micron-sized particles with U/Pu ratios of 1, 5, 10, 18, and 70 were produced from uranium and plutonium certified reference materials. In the TIMS analysis, the peaks of americium, plutonium, and uranium ion signals were successfully separated by continuously increasing the evaporation filament current. Consequently, the uranium and plutonium isotope ratios, except the (238)Pu/(239)Pu ratio, were successfully determined for the particles at all U/Pu ratios. This indicates that TIMS direct analysis allows for the measurement of individual U-Pu mixed particles without prior chemical separation. PMID:25479434

  17. Laser ablation inductively coupled plasma mass spectrometry measurement of isotope ratios in depleted uranium contaminated soils.

    PubMed

    Seltzer, Michael D

    2003-09-01

    Laser ablation of pressed soil pellets was examined as a means of direct sample introduction to enable inductively coupled plasma mass spectrometry (ICP-MS) screening of soils for residual depleted uranium (DU) contamination. Differentiation between depleted uranium, an anthropogenic contaminant, and naturally occurring uranium was accomplished on the basis of measured 235U/238U isotope ratios. The amount of sample preparation required for laser ablation is considerably less than that typically required for aqueous sample introduction. The amount of hazardous laboratory waste generated is diminished accordingly. During the present investigation, 235U/238U isotope ratios measured for field samples were in good agreement with those derived from gamma spectrometry measurements. However, substantial compensation was required to mitigate the effects of impaired pulse counting attributed to sample inhomogeneity and sporadic introduction of uranium analyte into the plasma. PMID:14611049

  18. Analytical Validation of Accelerator Mass Spectrometry for Pharmaceutical Development: the Measurement of Carbon-14 Isotope Ratio.

    SciTech Connect

    Keck, B D; Ognibene, T; Vogel, J S

    2010-02-05

    Accelerator mass spectrometry (AMS) is an isotope based measurement technology that utilizes carbon-14 labeled compounds in the pharmaceutical development process to measure compounds at very low concentrations, empowers microdosing as an investigational tool, and extends the utility of {sup 14}C labeled compounds to dramatically lower levels. It is a form of isotope ratio mass spectrometry that can provide either measurements of total compound equivalents or, when coupled to separation technology such as chromatography, quantitation of specific compounds. The properties of AMS as a measurement technique are investigated here, and the parameters of method validation are shown. AMS, independent of any separation technique to which it may be coupled, is shown to be accurate, linear, precise, and robust. As the sensitivity and universality of AMS is constantly being explored and expanded, this work underpins many areas of pharmaceutical development including drug metabolism as well as absorption, distribution and excretion of pharmaceutical compounds as a fundamental step in drug development. The validation parameters for pharmaceutical analyses were examined for the accelerator mass spectrometry measurement of {sup 14}C/C ratio, independent of chemical separation procedures. The isotope ratio measurement was specific (owing to the {sup 14}C label), stable across samples storage conditions for at least one year, linear over 4 orders of magnitude with an analytical range from one tenth Modern to at least 2000 Modern (instrument specific). Further, accuracy was excellent between 1 and 3 percent while precision expressed as coefficient of variation is between 1 and 6% determined primarily by radiocarbon content and the time spent analyzing a sample. Sensitivity, expressed as LOD and LLOQ was 1 and 10 attomoles of carbon-14 (which can be expressed as compound equivalents) and for a typical small molecule labeled at 10% incorporated with {sup 14}C corresponds to 30 fg

  19. Binary Cepheids: Separations and Mass Ratios in 5 M ⊙ Binaries

    NASA Astrophysics Data System (ADS)

    Evans, Nancy Evans; Bond, Howard E.; Schaefer, Gail H.; Mason, Brian D.; Karovska, Margarita; Tingle, Evan

    2013-10-01

    Deriving the distribution of binary parameters for a particular class of stars over the full range of orbital separations usually requires the combination of results from many different observing techniques (radial velocities, interferometry, astrometry, photometry, direct imaging), each with selection biases. However, Cepheids—cool, evolved stars of ~5 M ⊙—are a special case because ultraviolet (UV) spectra will immediately reveal any companion star hotter than early type A, regardless of the orbital separation. We have used International Ultraviolet Explorer UV spectra of a complete sample of all 76 Cepheids brighter than V = 8 to create a list of all 18 Cepheids with companions more massive than 2.0 M ⊙. Orbital periods of many of these binaries are available from radial-velocity studies, or can be estimated for longer-period systems from detected velocity variability. In an imaging survey with the Hubble Space Telescope Wide Field Camera 3, we resolved three of the companions (those of η Aql, S Nor, and V659 Cen), allowing us to make estimates of the periods out to the long-period end of the distribution. Combining these separations with orbital data in the literature, we derive an unbiased distribution of binary separations, orbital periods, and mass ratios. The distribution of orbital periods shows that the 5 M ⊙ binaries have systematically shorter periods than do 1 M ⊙ stars. Our data also suggest that the distribution of mass ratios depends on both binary separation and system multiplicity. The distribution of mass ratios as a function of orbital separation, however, does not depend on whether a system is a binary or a triple. Based in part on observations made with the NASA/ESA Hubble Space Telescope, obtained by the Space Telescope Science Institute. STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

  20. Determination of RW3-to-water mass-energy absorption coefficient ratio for absolute dosimetry.

    PubMed

    Seet, Katrina Y T; Hanlon, Peta M; Charles, Paul H

    2011-12-01

    The measurement of absorbed dose to water in a solid-phantom may require a conversion factor because it may not be radiologically equivalent to water. One phantom developed for the use of dosimetry is a solid water, RW3 white-polystyrene material by IBA. This has a lower mass-energy absorption coefficient than water due to high bremsstrahlung yield, which affects the accuracy of absolute dosimetry measurements. In this paper, we demonstrate the calculation of mass-energy absorption coefficient ratios, relative to water, from measurements in plastic water and RW3 with an Elekta Synergy linear accelerator (6 and 10 MV photon beams) as well as Monte Carlo modeling in BEAMnrc and DOSXYZnrc. From this, the solid-phantom-to-water correction factor was determined for plastic water and RW3. PMID:21960410

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

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

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

  2. Improving precision in resonance ionization mass spectrometry : influence of laser bandwidth in uranium isotope ratio measurements.

    SciTech Connect

    Isselhardt, B. H.; Savina, M. R.; Knight, K. B.; Pellin, M. J.; Hutcheon, I. D.; Prussin, S. G.

    2011-03-01

    The use of broad bandwidth lasers with automated feedback control of wavelength was applied to the measurement of {sup 235}U/{sup 238}U ratios by resonance ionization mass spectrometry (RIMS) to decrease laser-induced isotopic fractionation. By broadening the bandwidth of the first laser in a three-color, three-photon ionization process from a bandwidth of 1.8 GHz to about 10 GHz, the variation in sequential relative isotope abundance measurements decreased from 10% to less than 0.5%. This procedure was demonstrated for the direct interrogation of uranium oxide targets with essentially no sample preparation.

  3. On the electron to proton mass ratio and the proton structure

    NASA Astrophysics Data System (ADS)

    Trinhammer, Ole L.

    2013-05-01

    We derive an expression for the electron to nucleon mass ratio from a reinterpreted lattice gauge theory Hamiltonian to describe interior baryon dynamics. We use the classical electron radius as our fundamental length scale. Based on expansions on trigonometric Slater determinants for a neutral state, a specific numerical result is found to be less than three percent off the experimental value for the neutron. Via the exterior derivative on the Lie group configuration space u(3) we derive approximate parameter-free parton distribution functions that compare rather well with those for the u and d valence quarks of the proton.

  4. Intermediate-mass-ratio black-hole binaries: numerical relativity meets perturbation theory.

    PubMed

    Lousto, Carlos O; Nakano, Hiroyuki; Zlochower, Yosef; Campanelli, Manuela

    2010-05-28

    We study black-hole binaries in the intermediate-mass-ratio regime 0.01≲q≲0.1 with a new technique that makes use of nonlinear numerical trajectories and efficient perturbative evolutions to compute waveforms at large radii for the leading and nonleading (ℓ, m) modes. As a proof-of-concept, we compute waveforms for q=1/10. We discuss applications of these techniques for LIGO and VIRGO data analysis and the possibility that our technique can be extended to produce accurate waveform templates from a modest number of fully nonlinear numerical simulations. PMID:20867082

  5. On the charge to mass ratio of neutron cores and heavy nuclei

    SciTech Connect

    Patricelli, B.; Rotondo, M.; Ruffini, R.

    2008-01-03

    We determine theoretically the relation between the total number of protons N{sub p} and the mass number A (the charge to mass ratio) of nuclei and neutron cores with the model recently proposed by Ruffini et al. (2007) and we compare it with other N{sub p} versus A relations: the empirical one, related to the Periodic Table, and the semi-empirical relation, obtained by minimizing the Weizsaecker mass formula. We find that there is a very good agreement between all the relations for values of A typical of nuclei, with differences of the order of per cent. Our relation and the semi-empirical one are in agreement up to A{approx}10{sup 4}; for higher values, we find that the two relations differ. We interprete the different behaviour of our theoretical relation as a result of the penetration of electrons (initially confined in an external shell) inside the core, that becomes more and more important by increasing A; these effects are not taken into account in the semi-empirical mass-formula.

  6. Performance and limits of liquid chromatography isotope ratio mass spectrometry system for halogenated compounds

    NASA Astrophysics Data System (ADS)

    Gilevska, Tetyana; Gehre, Matthias; Richnow, Hans

    2014-05-01

    Compound Specific Isotope Analysis (CSIA) has been an important step for the assessment of the origin and fate of compounds in environmental science.[1] Biologically or pharmaceutically important compounds often are not amenable for gas chromatographic separation because of high polarity and lacking volatility, thermostability. In 2004 liquid chromatography isotope ratio mass spectrometry (LC-IRMS) became commercially available. LC-IRMS system intent a quantitative conversion of analytes separation into CO2 via wet oxidation with sodium persulfate in the presence of phosphoric acid while analytes are still dissolved in the aqueous liquid phase.[2] The aim of this study is to analyze the oxidation capacity of the interface of the LC-IRMS system and determine which parameters could improve oxidation of compounds which are resistant to persulfate oxidation. Oxidation capacity of the liquid chromatography isotope ratio mass spectrometry system was tested with halogenated acetic acid and a set of aromatic compounds with different substitutes. Acetic acid (AA) was taken as a model compound for complete oxidation and compared to the oxidation of other analytes on a molar basis. Correct values were obtained for di- and mono chlorinated and fluorinated and also for tribrominated acetic acid and for all studied aromatic compounds. Incomplete oxidation for trichloroacetic (TCAA) and trifluoroacetic (TFAA) acid was revealed with lower recovery compared to acetic acid and isotope fractionation leading to depleted carbon isotope composition compared to values obtained with an elementary analyzer connected to an isotope mass spectrometer Several optimization steps were tried in order to improve the oxidation of TCAA and TFAA: (i) increasing the concentration of the oxidizing agent, (ii) variation of flow rate of the oxidizing and acid solution, (iii) variation of flow rate of liquid chromatography pump (iv) addition of a catalyzer. These modifications lead to longer reaction time

  7. DEEP, LOW MASS RATIO OVERCONTACT BINARY SYSTEMS. XI. V1191 CYGNI

    SciTech Connect

    Zhu, L. Y.; Qian, S. B.; He, J. J.; Liu, L.

    2011-10-15

    Complete CCD photometric light curves in BV(RI){sub c} bands obtained on one night in 2009 for the short-period close-binary system V1191 Cygni are presented. A new photometric analysis with the 2003 version of the Wilson-Van Hamme code shows that V1191 Cyg is a W-type overcontact binary system and suggests that it has a high degree of overcontact (f = 68.6%) with very low mass ratio, implying that it is at the late stage of overcontact evolution. The absolute parameters of V1191 Cyg are derived using spectroscopic and photometric solutions. Combining new determined times of light minimum with others published in the literature, the period change of the binary star is investigated. A periodic variation, with a period of 26.7 years and an amplitude of 0.023 days, was discovered to be superimposed on a long-term period increase (dP/dt = +4.5({+-} 0.1) x 10{sup -7} days yr{sup -1}). The cyclic period oscillation may be caused by the magnetic activity cycles of either of the components or the light-time effect due to the presence of a third body with a mass of m{sub 3} = 0.77 M{sub sun} and an orbital radius of a{sub 3} = 7.6 AU, when this body is coplanar to the orbit of the eclipsing pair. The secular orbital period increase can be interpreted as a mass transfer from the less massive component to the more massive one. With the period increases, V1191 Cyg will evolve from its present low mass ratio, high filled overcontact state to a rapidly rotating single star when its orbital angular momentum is less than three times the total spin angular momentum. V1191 Cyg is too blue for its orbital period and it is an unusual W-type overcontact system with such a low mass ratio and high fill-out overcontact configuration, which is worth monitoring continuously in the future.

  8. The ratio of CO to total gas mass in high-redshift galaxies

    NASA Astrophysics Data System (ADS)

    Mashian, Natalie; Sternberg, Amiel; Loeb, Abraham

    2013-11-01

    Walter et al. have recently identified the J = 6 - 5, 5 - 4, and 2 - 1 CO rotational emission lines, and [C II] fine-structure emission line from the star-forming interstellar medium (ISM) in the high-redshift submillimetre source HDF 850.1, at z = 5.183. We employ large velocity gradient (LVG) modelling to analyse the spectra of this source assuming the [C II] and CO emissions originate from (i) separate virialized regions, (ii) separate unvirialized regions, (iii) uniformly mixed virialized regions and (iv) uniformly mixed unvirialized regions. We present the best-fitting set of parameters, including for each case the ratio α between the total hydrogen/helium gas mass and the CO(1-0) line luminosity. We also present computations of the ratio of H2 mass to [C II] line luminosity for optically thin conditions, for a range of gas temperatures and densities, for direct conversion of [C II] line luminosities to `CO-dark' H2 masses. For HDF 850.1 we find that a model in which the CO and C+ are uniformly mixed in gas that is shielded from ultraviolet radiation requires a cosmic ray or X-ray ionization rate of ζ ≈ 3 × 10-14 s-1, plausibly consistent with the large star formation rate (˜103 M⊙ yr-1) observed in this source. Enforcing the cosmological constraint posed by the abundance of dark matter haloes in the standard Λ cold dark matter (ΛCDM) cosmology and taking into account other possible contributions to the total gas mass, we find that the two models in which the virialization condition is enforced can be ruled out at the ≳2σ level, while the model assuming mixed unvirialized regions is less likely. We conclude that modelling HDF 850.1's ISM as a collection of unvirialized molecular clouds with distinct CO and C+ layers, for which α = 1.2 M⊙ (K km s-1 pc2)-1 for the CO to H2 mass-to-luminosity ratio (similar to the standard ultraluminous infrared galaxy value), is most consistent with the ΛCDM cosmology.

  9. Precipitation chemistry and corresponding transport patterns of influencing air masses at Huangshan Mountain in East China

    NASA Astrophysics Data System (ADS)

    Shi, ChunE; Deng, Xueliang; Yang, Yuanjian; Huang, Xiangrong; Wu, Biwen

    2014-09-01

    One hundred and ten samples of rainwater were collected for chemical analysis at the summit of Huangshan Mountain, a high-altitude site in East China, from July 2010 to June 2011. The volume-weighted-mean (VWM) pH for the whole sampling period was 5.03. SO{4/2-} and Ca2+ were the most abundant anion and cation, respectively. The ionic concentrations varied monthly with the highest concentrations in winter/spring and the lowest in summer. Evident inter-correlations were found among most ions, indicating the common sources for some species and fully mixing characteristics of the alpine precipitation chemistry. The VWM ratio of [SO{4/2-}]/[NO{3/-}] was 2.54, suggesting the acidity of rainwater comes from both nitric and sulfuric acids. Compared with contemporary observations at other alpine continental sites in China, the precipitation at Huangshan Mountain was the least polluted, with the lowest ionic concentrations. Trajectories to Huangshan Mountain on rainy days could be classified into six groups. The rainwater with influencing air masses originating in Mongolia was the most polluted with limited effect. The emissions of Jiangxi, Anhui, Zhejiang and Jiangsu provinces had a strong influence on the overall rain chemistry at Huangshan Mountain. The rainwater with influencing air masses from Inner Mongolia was heavily polluted by anthropogenic pollutants.

  10. Real-Time Optical Fuel-to-Air Ratio Sensor for Gas Turbine Combustors

    NASA Technical Reports Server (NTRS)

    Nguyen, Quang-Viet; Mongia, Rajiv K.; Dibble, Robert W.

    1999-01-01

    The measurement of the temporal distribution of fuel in gas turbine combustors is important in considering pollution, combustion efficiency and combustor dynamics and acoustics. Much of the previous work in measuring fuel distributions in gas turbine combustors has focused on the spatial aspect of the distribution. The temporal aspect however, has often been overlooked, even though it is just as important. In part, this is due to the challenges of applying real-time diagnostic techniques in a high pressure and high temperature environment. A simple and low-cost instrument that non-intrusively measures the real-time fuel-to-air ratio (FAR) in a gas turbine combustor has been developed. The device uses a dual wavelength laser absorption technique to measure the concentration of most hydrocarbon fuels such as jet fuel, methane, propane, etc. The device can be configured to use fiber optics to measure the local FAR inside a high pressure test rig without the need for windows. Alternatively, the device can readily be used in test rigs that have existing windows without modifications. An initial application of this instrument was to obtain time-resolved measurements of the FAR in the premixer of a lean premixed prevaporized (LPP) combustor at inlet air pressures and temperatures as high as 17 atm at 800 K, with liquid JP-8 as the fuel. Results will be presented that quantitatively show the transient nature of the local FAR inside a LPP gas turbine combustor at actual operating conditions. The high speed (kHz) time resolution of this device, combined with a rugged fiber optic delivery system, should enable the realization of a flight capable active-feedback and control system for the abatement of noise and pollutant emissions in the future. Other applications that require an in-situ and time-resolved measurement of fuel vapor concentrations should also find this device to be of use.

  11. Determination of the sulfur isotope ratio in carbonyl sulfide using gas chromatography/isotope ratio mass spectrometry on fragment ions 32S+, 33S+, and 34S+.

    PubMed

    Hattori, Shohei; Toyoda, Akari; Toyoda, Sakae; Ishino, Sakiko; Ueno, Yuichiro; Yoshida, Naohiro

    2015-01-01

    Little is known about the sulfur isotopic composition of carbonyl sulfide (OCS), the most abundant atmospheric sulfur species. We present a promising new analytical method for measuring the stable sulfur isotopic compositions (δ(33)S, δ(34)S, and Δ(33)S) of OCS using nanomole level samples. The direct isotopic analytical technique consists of two parts: a concentration line and online gas chromatography-isotope ratio mass spectrometry (GC-IRMS) using fragmentation ions (32)S(+), (33)S(+), and (34)S(+). The current levels of measurement precision for OCS samples greater than 8 nmol are 0.42‰, 0.62‰, and 0.23‰ for δ(33)S, δ(34)S, and Δ(33)S, respectively. These δ and Δ values show a slight dependence on the amount of injected OCS for volumes smaller than 8 nmol. The isotope values obtained from the GC-IRMS method were calibrated against those measured by a conventional SF6 method. We report the first measurement of the sulfur isotopic composition of OCS in air collected at Kawasaki, Kanagawa, Japan. The δ(34)S value obtained for OCS (4.9 ± 0.3‰) was lower than the previous estimate of 11‰. When the δ(34)S value for OCS from the atmospheric sample is postulated as the global signal, this finding, coupled with isotopic fractionation for OCS sink reactions in the stratosphere, explains the reported δ(34)S for background stratospheric sulfate. This suggests that OCS is a potentially important source for background (nonepisodic or nonvolcanic) stratospheric sulfate aerosols. PMID:25439590

  12. Mathematical modeling of heat exchange between mine air and rock mass during fire

    SciTech Connect

    A.E. Krasnoshtein; B.P. Kazakov; A.V. Shalimov

    2006-05-15

    Solution of problems on heat exchange between ventilating air and rock mass and on gas admixture propagation in mine workings serve as a base for considering changes in heat-gas-air state at a mine after inflammation. The presented mathematical relations allow calculation of a varied velocity and movement direction of air flows, their temperatures and smoking conditions during fire.

  13. A New Class of Nascent Eclipsing Binaries with Extreme Mass Ratios

    NASA Astrophysics Data System (ADS)

    Moe, Maxwell; Di Stefano, Rosanne

    2015-03-01

    Early B-type main-sequence (MS) stars (M 1 ≈ 5-16 M ⊙) with closely orbiting low-mass stellar companions (q = M 2/M 1 < 0.25) can evolve to produce Type Ia supernovae, low-mass X-ray binaries, and millisecond pulsars. However, the formation mechanism and intrinsic frequency of such close extreme mass-ratio binaries have been debated, especially considering none have hitherto been detected. Utilizing observations of the Large Magellanic Cloud galaxy conducted by the Optical Gravitational Lensing Experiment, we have discovered a new class of eclipsing binaries in which a luminous B-type MS star irradiates a closely orbiting low-mass pre-MS companion that has not yet fully formed. The primordial pre-MS companions have large radii and discernibly reflect much of the light they intercept from the B-type MS primaries (ΔI refl ≈ 0.02-0.14 mag). For the 18 definitive MS + pre-MS eclipsing binaries in our sample with good model fits to the observed light-curves, we measure short orbital periods P = 3.0-8.5 days, young ages τ ≈ 0.6-8 Myr, and small secondary masses M 2 ≈ 0.8-2.4 M ⊙ (q ≈ 0.07-0.36). The majority of these nascent eclipsing binaries are still associated with stellar nurseries, e.g., the system with the deepest eclipse ΔI 1 = 2.8 mag and youngest age τ = 0.6 ± 0.4 Myr is embedded in the bright H II region 30 Doradus. After correcting for selection effects, we find that (2.0 ± 0.6)% of B-type MS stars have companions with short orbital periods P = 3.0-8.5 days and extreme mass ratios q ≈ 0.06-0.25. This is ≈10 times greater than that observed for solar-type MS primaries. We discuss how these new eclipsing binaries provide invaluable insights, diagnostics, and challenges for the formation and evolution of stars, binaries, and H II regions.

  14. Vertical air mass exchange driven by the local circulation on the northern slope of Mount Everest

    NASA Astrophysics Data System (ADS)

    Zhou, Libo; Zou, Han; Ma, Shupo; Li, Peng; Zhu, Jinhuan; Huo, Cuiping

    2011-01-01

    To better understand vertical air mass exchange driven by local circulation in the Himalayas, the volume flux of air mass is estimated in the Rongbuk Valley on the northern slope of Mount Everest, based on a volume closure method and wind-profiler measurements during the HEST2006 campaign in June 2006. Vertical air mass exchange was found to be dominated by a strong downward mass transfer from the late morning to late night. The average vertical air volume flux was 0.09 m s-1, which could be equivalent to a daily ventilation of 30 times the enclosed valley volume. This vertical air mass exchange process was greatly affected by the evolution of the South Asian summer monsoon (SASM), with a strong downward transfer during the SASM break stage, and a weak transfer during the SASM active stage.

  15. Eccentric-orbit extreme-mass-ratio inspiral gravitational wave energy fluxes to 7PN order

    NASA Astrophysics Data System (ADS)

    Forseth, Erik; Evans, Charles R.; Hopper, Seth

    2016-03-01

    We present new results through 7PN order on the energy flux from eccentric extreme-mass-ratio binaries. The black hole perturbation calculations are made at very high accuracy (200 decimal places) using a Mathematica code based on the Mano-Suzuki-Takasugi analytic function expansion formalism. All published coefficients in the expansion through 3PN order at lowest order in the mass ratio are confirmed and new analytic and numeric terms are found to high order in powers of e2 at post-Newtonian orders between 3.5PN and 7PN. We also show original work in finding (nearly) arbitrarily accurate expansions for hereditary terms at 1.5PN, 2.5PN, and 3PN orders. An asymptotic analysis is developed that guides an understanding of eccentricity singular factors, which diverge at unit eccentricity and which appear at each PN order. We fit to a model at each PN order that includes these eccentricity singular factors, which allows the flux to be accurately determined out to e →1 .

  16. Binary black hole merger gravitational waves and recoil in the large mass ratio limit

    SciTech Connect

    Sundararajan, Pranesh A.; Hughes, Scott A.; Khanna, Gaurav

    2010-05-15

    Spectacular breakthroughs in numerical relativity now make it possible to compute spacetime dynamics in almost complete generality, allowing us to model the coalescence and merger of binary black holes with essentially no approximations. The primary limitation of these calculations is now computational. In particular, it is difficult to model systems with large mass ratio and large spins, since one must accurately resolve the multiple length scales that play a role in such systems. Perturbation theory can play an important role in extending the reach of computational modeling for binary systems. In this paper, we present first results of a code that allows us to model the gravitational waves generated by the inspiral, merger, and ringdown of a binary system in which one member of the binary is much more massive than the other. This allows us to accurately calibrate binary dynamics in the large mass ratio regime. We focus in this analysis on the recoil imparted to the merged remnant by these waves. We closely examine the ''antikick,'' an antiphase cancellation of the recoil arising from the plunge and ringdown waves, described in detail by Schnittman et al. We find that, for orbits aligned with the black hole spin, the antikick grows as a function of spin. The total recoil is smallest for prograde coalescence into a rapidly rotating black hole, and largest for retrograde coalescence. Amusingly, this completely reverses the predicted trend for kick versus spin from analyses that only include inspiral information.

  17. Deep Atmosphere Ammonia Mixing Ratio at Jupiter from the Galileo Probe Mass Spectrometer

    NASA Technical Reports Server (NTRS)

    Mahaffy, P. R.; Niemann, H. B.; Demick, J. E.

    1999-01-01

    New laboratory studies employing the Engineering Unit (EU) of the Galileo Probe Mass Spectrometer (GPMS) have resulted in a substantial reduction in the previously reported upper limit on the ammonia mixing ratio derived from the GPMS experiment at Jupiter. This measurement is complicated by background ammonia contributions in the GPMS during direct atmospheric sampling produced from the preceding gas enrichment experiments. These backgrounds can be quantified with the data from the EU studies when they are carried out in a manner that duplicates the descent profile of pressure and enrichment cell loading. This background is due to the tendency of ammonia to interact strongly with the walls of the mass spectrometer and on release to contribute to the gas being directly directed into the ion source from the atmosphere through a capillary pressure reduction leak. It is evident from the GPMS and other observations that the mixing ratio of ammonia at Jupiter reaches the deep atmosphere value at substantially higher pressures than previously assumed. This is a likely explanation for the previously perceived discrepancy between ammonia values derived from ground based microwave observations and those obtained from attenuation of the Galileo Probe radio signal.

  18. UBVRI analysis of the totally eclipsing extreme mass ratio W UMa binary, GSC 3208 1986

    SciTech Connect

    Samec, R. G.; Kring, J. D.; Robb, Russell; Van Hamme, W.; Faulkner, D. R.

    2015-03-01

    GSC 3208 1986 is an NSVS and TYCHO binary, first observed from 1999 to 2000. It is a W UMa binary with a period of 0.405 days. The present observations were taken in 2012 September and are of high precision, averaging a standard deviation of better than 5 mmag. The amplitude of the light curve is very nearly 0.5 mag yet it undergoes total eclipses. Dominion Astrophysical Observatory spectra give an F3V type (T∼6900 K) for the system, the earliest of the extreme mass ratio W UMa binaries. The linear period determination of 0.4045672 days was calculated with the two sets of epochs available. An early NSVS light curve reveals that the period has been smoothly decreasing over its past 12,000 orbits. The binary may be undergoing sinusoidal oscillations due to the presence of a third body, possibly with a period of 23±3 years. The high inclination of 85° results in a long duration secondary total eclipse, lasting some 49.5 minutes. Findings indicate that GSC 3208 1986 is an immaculate extreme mass ratio, q(m{sub 2}/m{sub 1}) = 0.24, A-type W UMa binary.

  19. Stable isotope ratio mass spectrometry of nanogram quantities of boron and sulfur

    NASA Astrophysics Data System (ADS)

    Wieser, Michael Eugene

    1998-09-01

    Instrumentation and analytical techniques were developed to measure isotope abundances from nanograms of sulfur and boron. Sulfur isotope compositions were determined employing continuous flow isotope ratio mass spectroscopy (CF-IRMS) procedures and AsS+ thermal ionization mass spectrometry techniques (AsS+-TIMS). Boron isotope abundances were determined by BO2/sp--TIMS. CF-IRMS measurements realized δ34S values from 10 μg sulfur with precisions of ±0.3/perthous. To extend sulfur isotope measurements to much smaller samples, a TIMS procedure was developed to measure 75As32S+ and 75As34S+ at masses 108 and 109 from 200 ng S on a Finnigan MAT 262 with an ion counter. This is possibly the smallest amount of sulfur which has been successfully analyzed isotopically. The internal precision of 32S/34S ratios measured by AsS+-TIMS was better than ±0.15 percent. δ34S-values calculated relative to the measured 32S/34S value of an IAEA AG2S standard (S-1) agreed with those determined by CF-IRMS to within ±3/perthous. The increasing sensitivity of S-isotope analyses permits hiterto impossible investigations e.g. sulfur in tree rings and ice cores. Boron isotope abundances were measured as BO2/sp- from 50 ng B using an older thermal ionization mass spectrometer which had been extensively upgraded including the addition of computer control electronics, sensitive ion current amplification and fiber optic data bus. The internal precisions of the measured 11B/10B ratios were ±0.15 percent and the precisions of δ11B values calculated relative to the accepted international standard (SRM-951) were ±3/perthous. Two applications of boron isotope abundance variations were initiated (1) ground waters of Northern Alberta and (2) coffee beans in different regions of the world. In the first it was demonstrated that boron isotopes could be used to trace boron released during steam injection of oil sands into the surrounding environment. Data from the second study suggest that boron

  20. A global review of species-specific shark-fin-to-body-mass ratios and relevant legislation.

    PubMed

    Biery, L; Pauly, D

    2012-04-01

    In this review, shark-fin-to-body-mass ratios, which have been legislated by several countries as a means of regulating and monitoring shark fisheries, have been compiled and reviewed. Observed and legislated wet-fin-mass-to-round-mass (M(fw) :M(r) ) ratios have been collected for 50 species and eight countries. Wet to dry-fin mass conversion factors have also been reviewed. Existing shark fishery legislation was compiled by political entity and regional fishery management organizations (RFMO). The mean observed M(fw) :M(r) ratio for all species was 3·0%, but actual fin to body-mass ratios varied considerably by species and location. Species-specific mean ratios ranged from 1·1 to 10·9%, and estimated mean ratios ranged from 1·5 to 6·1% by country, depending on fin-cutting practices and the mix of exploited species. The mean conversion factor for wet to dry-fin mass was 0·43. Shark-related legislation was found to exist in 37 countries and the 22 maritime members of the European Union, and shark-related regulations have been designated by nine RFMOs. Results suggest that currently regulated ratios may not be appropriate for all species and fin-cutting practices, and regulations based on generalized ratios for all sharks may be inadequate. Alternative policies may be necessary for the effective management of global shark fisheries. PMID:22497402

  1. The gas-to-dust mass ratio of Centaurus A as seen by Herschel

    NASA Astrophysics Data System (ADS)

    Parkin, T. J.; Wilson, C. D.; Foyle, K.; Baes, M.; Bendo, G. J.; Boselli, A.; Boquien, M.; Cooray, A.; Cormier, D.; Davies, J. I.; Eales, S. A.; Galametz, M.; Gomez, H. L.; Lebouteiller, V.; Madden, S.; Mentuch, E.; Page, M. J.; Pohlen, M.; Remy, A.; Roussel, H.; Sauvage, M.; Smith, M. W. L.; Spinoglio, L.

    2012-05-01

    We present photometry of the nearby galaxy NGC 5128 (Centaurus A) observed with the Photodetector Array Camera and Spectrometer (PACS) and Spectral and Photometric Imaging Receiver (SPIRE) instruments on board the Herschel Space Observatory, at 70, 160, 250, 350 and 500 μm, as well as new CO J= 3-2 observations taken with the HARP-B instrument on the James Clerk Maxwell Telescope (JCMT). Using a single-component modified blackbody, we model the dust spectral energy distribution within the disc of the galaxy using all five Herschel wavebands and find dust temperatures of ˜30 K towards the centre of the disc and a smoothly decreasing trend to ˜20 K with increasing radius. We find a total dust mass of (1.59 ± 0.05) × 107 M⊙ and a total gas mass of (2.7 ± 0.2) × 109 M⊙. The average gas-to-dust mass ratio is 103 ± 8, but we find an interesting increase in this ratio to approximately 275 towards the centre of Cen A. We discuss several possible physical processes that may be causing this effect, including dust sputtering, jet entrainment and systematic variables such as the XCO factor. Dust sputtering by X-rays originating in the active galactic nucleus or the removal of dust by the jets is our most favoured explanation. a PACS values are divisive and SPIRE values are multiplicative. b These uncertainties are for the pixels at their native pixel scale, as listed in this table. c We have ignored the fact that the SPIRE calibration errors are correlated between all three bands and our total 7 per cent error comprises 5 per cent correlated error and 5 per cent uncorrelated error.

  2. Changes of air-tissue ratio evaluated by EBCT after cardiopulmonary resuscitation (CPR): validation in swine

    NASA Astrophysics Data System (ADS)

    Recheis, Wolfgang A.; Schuster, Antonius H.; Kleinsasser, Axel; Loeckinger, Alexander; Hoermann, Christoph; zur Nedden, Dieter

    2001-05-01

    The purpose was to evaluate changes of the air-tissue ratio (ATR) in previously defined regions of interest after cardiopulmonary resuscitation (CPR) in porcine model. Eight anesthetized and ventilated pigs we scanned in supine position before and 30 minutes after CPR at two different constant PEEP levels (5 cm H2O, 15 cm H2O). Volume scans were obtained using 6 mm slices. The gray values of the lung were divided into steps of 100 HU in order to get access to the changes of ATR. ATR was evaluated in ventral, intermediate and dorsal regions of the lung. CPR for 9 minutes led to an uneven distribution of ventilation. In the ventral region, areas with high ATR increased. Areas with normal ATR decreased. In contrast the dorsal regions with low ATR increased. ATR in the intermediate regions remained almost unchanged. Using the higher PEEP level, areas with normal ATR showed a marked increase accompanied by a decrease of areas with low ATR. After CPR, an uneven distribution of lung aeration was detected. According to the impaired hemodynamics, areas with normal ATR decreased and areas with high and low ATR increased. Using higher PEEP levels improved lung aeration.

  3. Adaptive critic learning techniques for engine torque and air-fuel ratio control.

    PubMed

    Liu, Derong; Javaherian, Hossein; Kovalenko, Olesia; Huang, Ting

    2008-08-01

    A new approach for engine calibration and control is proposed. In this paper, we present our research results on the implementation of adaptive critic designs for self-learning control of automotive engines. A class of adaptive critic designs that can be classified as (model-free) action-dependent heuristic dynamic programming is used in this research project. The goals of the present learning control design for automotive engines include improved performance, reduced emissions, and maintained optimum performance under various operating conditions. Using the data from a test vehicle with a V8 engine, we developed a neural network model of the engine and neural network controllers based on the idea of approximate dynamic programming to achieve optimal control. We have developed and simulated self-learning neural network controllers for both engine torque (TRQ) and exhaust air-fuel ratio (AFR) control. The goal of TRQ control and AFR control is to track the commanded values. For both control problems, excellent neural network controller transient performance has been achieved. PMID:18632389

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

    NASA Astrophysics Data System (ADS)

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

    2013-08-01

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

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

    SciTech Connect

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

    2013-08-01

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

  6. Assessment of aerosol's mass concentrations from measured linear particle depolarization ratio (vertically resolved) and simulations

    NASA Astrophysics Data System (ADS)

    Nemuc, A.; Vasilescu, J.; Talianu, C.; Belegante, L.; Nicolae, D.

    2013-11-01

    Multi-wavelength depolarization Raman lidar measurements from Magurele, Romania are used in this study along with simulated mass-extinction efficiencies to calculate the mass concentration profiles of different atmospheric components, due to their different depolarization contribution to the 532 nm backscatter coefficient. Linear particle depolarization ratio (δpart) was computed using the relative amplification factor and the system-dependent molecular depolarization. The low depolarizing component was considered as urban/smoke, with a mean δpart of 3%, while for the high depolarizing component (mineral dust) a mean δpart of 35% was assumed. For this study 11 months of lidar measurements were analysed. Two study cases are presented in details: one for a typical Saharan dust aerosol intrusion, 10 June 2012 and one for 12 July 2012 when a lofted layer consisting of biomass burning smoke extended from 3 to 4.5 km height. Optical Properties of Aerosols and Clouds software package (OPAC) classification and conversion factors were used to calculate mass concentrations. We found that calibrated depolarization measurements are critical in distinguishing between smoke-reach aerosol during the winter and dust-reach aerosol during the summer, as well as between elevated aerosol layers having different origins. Good agreement was found between lidar retrievals and DREAM- Dust REgional Atmospheric Model forecasts in cases of Saharan dust. Our method was also compared against LIRIC (The Lidar/Radiometer Inversion Code) and very small differences were observed.

  7. Assessment of aerosol's mass concentrations from measured linear particle depolarization ratio (vertically resolved) and simulations

    NASA Astrophysics Data System (ADS)

    Nemuc, A.; Vasilescu, J.; Talianu, C.; Belegante, L.; Nicolae, D.

    2013-06-01

    Multiwavelength depolarization Raman lidar measurements from Magurele, Romania are used in this study along with simulated mass-extinction efficiencies to calculate the mass concentrations profiles of different atmospheric components, due to their different depolarization contribution to the 532 nm backscatter coefficient. Linear particle depolarization ratio (δpart) was computed using the relative amplification factor and the system-dependent molecular depolarization. The low depolarizing component was considered as urban/smoke, with a mean δpart of 3%, while for the high depolarizing component (mineral dust) a mean δpart of 35% was assumed. For this study 11 months of lidar measurements were analyzed. Two study cases are presented in details: one for a typical Saharan dust aerosol intrusion, 10 June 2012 and one for 12 July 2012 when a lofted layer consisting of biomass burning smoke extended from 3 to 4.5 km height. Optical Properties of Aerosols and Clouds software package (OPAC) classification and conversion factors were used to calculate mass concentrations. We found that calibrated depolarization measurements are critical to distinguish between smoke-reach aerosol during the winter and dust-reach aerosol during the summer, as well as between elevated aerosol layers having different origins. Good agreement was found between lidar retrievals and DREAM- Dust REgional Atmospheric Model forecasts in cases of Saharan dust. Our method was also compared against LIRIC (The Lidar/Radiometer Inversion Code) and very small differences were observed.

  8. Acquisition and processing of data for isotope-ratio-monitoring mass spectrometry

    NASA Technical Reports Server (NTRS)

    Ricci, M. P.; Merritt, D. A.; Freeman, K. H.; Hayes, J. M.

    1994-01-01

    Methods are described for continuous monitoring of signals required for precise analyses of 13C, 18O, and 15N in gas streams containing varying quantities of CO2 and N2. The quantitative resolution (i.e. maximum performance in the absence of random errors) of these methods is adequate for determination of isotope ratios with an uncertainty of one part in 10(5); the precision actually obtained is often better than one part in 10(4). This report describes data-processing operations including definition of beginning and ending points of chromatographic peaks and quantitation of background levels, allowance for effects of chromatographic separation of isotopically substituted species, integration of signals related to specific masses, correction for effects of mass discrimination, recognition of drifts in mass spectrometer performance, and calculation of isotopic delta values. Characteristics of a system allowing off-line revision of parameters used in data reduction are described and an algorithm for identification of background levels in complex chromatograms is outlined. Effects of imperfect chromatographic resolution are demonstrated and discussed and an approach to deconvolution of signals from coeluting substances described.

  9. The Contribution of Halos with Different Mass Ratios to the Overall Growth of Cluster-sized Halos

    NASA Astrophysics Data System (ADS)

    Lemze, Doron; Postman, Marc; Genel, Shy; Ford, Holland C.; Balestra, Italo; Donahue, Megan; Kelson, Daniel; Nonino, Mario; Mercurio, Amata; Biviano, Andrea; Rosati, Piero; Umetsu, Keiichi; Sand, David; Koekemoer, Anton; Meneghetti, Massimo; Melchior, Peter; Newman, Andrew B.; Bhatti, Waqas A.; Voit, G. Mark; Medezinski, Elinor; Zitrin, Adi; Zheng, Wei; Broadhurst, Tom; Bartelmann, Matthias; Benitez, Narciso; Bouwens, Rychard; Bradley, Larry; Coe, Dan; Graves, Genevieve; Grillo, Claudio; Infante, Leopoldo; Jimenez-Teja, Yolanda; Jouvel, Stephanie; Lahav, Ofer; Maoz, Dan; Merten, Julian; Molino, Alberto; Moustakas, John; Moustakas, Leonidas; Ogaz, Sara; Scodeggio, Marco; Seitz, Stella

    2013-10-01

    We provide a new observational test for a key prediction of the ΛCDM cosmological model: the contributions of mergers with different halo-to-main-cluster mass ratios to cluster-sized halo growth. We perform this test by dynamically analyzing 7 galaxy clusters, spanning the redshift range 0.13 < z c < 0.45 and caustic mass range 0.4-1.5 10^{15}\\, h_{0.73}^{-1} M ⊙, with an average of 293 spectroscopically confirmed bound galaxies to each cluster. The large radial coverage (a few virial radii), which covers the whole infall region, with a high number of spectroscopically identified galaxies enables this new study. For each cluster, we identify bound galaxies. Out of these galaxies, we identify infalling and accreted halos and estimate their masses and their dynamical states. Using the estimated masses, we derive the contribution of different mass ratios to cluster-sized halo growth. For mass ratios between ~0.2 and ~0.7, we find a ~1σ agreement with ΛCDM expectations based on the Millennium simulations I and II. At low mass ratios, <~ 0.2, our derived contribution is underestimated since the detection efficiency decreases at low masses, ~2 × 1014 h_{0.73}^{-1} M ⊙. At large mass ratios, >~ 0.7, we do not detect halos probably because our sample, which was chosen to be quite X-ray relaxed, is biased against large mass ratios. Therefore, at large mass ratios, the derived contribution is also underestimated.

  10. THE CONTRIBUTION OF HALOS WITH DIFFERENT MASS RATIOS TO THE OVERALL GROWTH OF CLUSTER-SIZED HALOS

    SciTech Connect

    Lemze, Doron; Ford, Holland C.; Medezinski, Elinor; Postman, Marc; Koekemoer, Anton; Genel, Shy; Balestra, Italo; Nonino, Mario; Biviano, Andrea; Kelson, Daniel; Voit, G. Mark; Mercurio, Amata; Umetsu, Keiichi; Sand, David; Meneghetti, Massimo; Melchior, Peter; Newman, Andrew B.; Bhatti, Waqas A.; and others

    2013-10-20

    We provide a new observational test for a key prediction of the ΛCDM cosmological model: the contributions of mergers with different halo-to-main-cluster mass ratios to cluster-sized halo growth. We perform this test by dynamically analyzing 7 galaxy clusters, spanning the redshift range 0.13 < z{sub c} < 0.45 and caustic mass range 0.4-1.5 10{sup 15} h{sub 0.73}{sup -1} M{sub ☉}, with an average of 293 spectroscopically confirmed bound galaxies to each cluster. The large radial coverage (a few virial radii), which covers the whole infall region, with a high number of spectroscopically identified galaxies enables this new study. For each cluster, we identify bound galaxies. Out of these galaxies, we identify infalling and accreted halos and estimate their masses and their dynamical states. Using the estimated masses, we derive the contribution of different mass ratios to cluster-sized halo growth. For mass ratios between ∼0.2 and ∼0.7, we find a ∼1σ agreement with ΛCDM expectations based on the Millennium simulations I and II. At low mass ratios, ∼< 0.2, our derived contribution is underestimated since the detection efficiency decreases at low masses, ∼2 × 10{sup 14} h{sub 0.73}{sup -1} M{sub ☉}. At large mass ratios, ∼> 0.7, we do not detect halos probably because our sample, which was chosen to be quite X-ray relaxed, is biased against large mass ratios. Therefore, at large mass ratios, the derived contribution is also underestimated.

  11. A Comparison of the Red Green Blue Air Mass Imagery and Hyperspectral Infrared Retrieved Profiles

    NASA Technical Reports Server (NTRS)

    Berndt, E. B.; Folmer, Michael; Dunion, Jason

    2014-01-01

    The Red Green Blue (RGB) Air Mass imagery is derived from multiple channels or paired channel differences. Multiple channel products typically provide additional information than a single channel can provide alone. The RGB Air Mass imagery simplifies the interpretation of temperature and moisture characteristics of air masses surrounding synoptic and mesoscale features. Despite the ease of interpretation of multiple channel products, the combination of channels and channel differences means the resulting product does not represent a quantity or physical parameter such as brightness temperature in conventional single channel satellite imagery. Without a specific quantity to reference, forecasters are often confused as to what RGB products represent. Hyperspectral infrared retrieved profiles of temperature, moisture, and ozone can provide insight about the air mass represented on the RGB Air Mass product and provide confidence in the product and representation of air masses despite the lack of a quantity to reference for interpretation. This study focuses on RGB Air Mass analysis of Hurricane Sandy as it moved north along the U.S. East Coast, while transitioning to a hybrid extratropical storm. Soundings and total column ozone retrievals were analyzed using data from the Cross-track Infrared and Advanced Technology Microwave Sounder Suite (CrIMSS) on the Suomi National Polar Orbiting Partnership satellite and the Atmospheric Infrared Sounder (AIRS) on the National Aeronautics and Space Administration Aqua satellite along with dropsondes that were collected from National Oceanic and Atmospheric Administration and Air Force research aircraft. By comparing these datasets to the RGB Air Mass, it is possible to capture quantitative information that could help in analyzing the synoptic environment enough to diagnose the onset of extratropical transition. This was done by identifying any stratospheric air intrusions (SAIs) that existed in the vicinity of Sandy as the wind

  12. Protein stable isotope fingerprinting: multidimensional protein chromatography coupled to stable isotope-ratio mass spectrometry.

    PubMed

    Mohr, Wiebke; Tang, Tiantian; Sattin, Sarah R; Bovee, Roderick J; Pearson, Ann

    2014-09-01

    Protein stable isotope fingerprinting (P-SIF) is a method to measure the carbon isotope ratios of whole proteins separated from complex mixtures, including cultures and environmental samples. The goal of P-SIF is to expose the links between taxonomic identity and metabolic function in microbial ecosystems. To accomplish this, two dimensions of chromatography are used in sequence to resolve a sample containing ca. 5-10 mg of mixed proteins into 960 fractions. Each fraction then is split in two aliquots: The first is digested with trypsin for peptide sequencing, while the second has its ratio of (13)C/(12)C (value of δ(13)C) measured in triplicate using an isotope-ratio mass spectrometer interfaced with a spooling wire microcombustion device. Data from cultured species show that bacteria have a narrow distribution of protein δ(13)C values within individual taxa (±0.7-1.2‰, 1σ). This is moderately larger than the mean precision of the triplicate isotope measurements (±0.5‰, 1σ) and may reflect heterogeneous distribution of (13)C among the amino acids. When cells from different species are mixed together prior to protein extraction and separation, the results can predict accurately (to within ±1σ) the δ(13)C values of the original taxa. The number of data points required for this endmember prediction is ≥20/taxon, yielding a theoretical resolution of ca. 10 taxonomic units/sample. Such resolution should be useful to determine the overall trophic breadth of mixed microbial ecosystems. Although we utilize P-SIF to measure natural isotope ratios, it also could be combined with experiments that incorporate stable isotope labeling. PMID:25121924

  13. Air Mass Origin in the Arctic and its Response to Future Warming

    NASA Technical Reports Server (NTRS)

    Orbe, Clara; Newman, Paul A.; Waugh, Darryn W.; Holzer, Mark; Oman, Luke; Polvani, Lorenzo M.; Li, Feng

    2014-01-01

    We present the first climatology of air mass origin in the Arctic in terms of rigorously defined air mass fractions that partition air according to where it last contacted the planetary boundary layer (PBL). Results from a present-day climate integration of the GEOSCCM general circulation model reveal that the Arctic lower troposphere below 700 mb is dominated year round by air whose last PBL contact occurred poleward of 60degN, (Arctic air, or air of Arctic origin). By comparison, approx. 63% of the Arctic troposphere above 700 mb originates in the NH midlatitude PBL, (midlatitude air). Although seasonal changes in the total fraction of midlatitude air are small, there are dramatic changes in where that air last contacted the PBL, especially above 700 mb. Specifically, during winter air in the Arctic originates preferentially over the oceans, approx. 26% in the East Pacific, and approx. 20% in the Atlantic PBL. By comparison, during summer air in the Arctic last contacted the midlatitude PBL primarily over land, overwhelmingly so in Asia (approx. 40 %) and, to a lesser extent, in North America (approx. 24%). Seasonal changes in air-mass origin are interpreted in terms of seasonal variations in the large-scale ventilation of the midlatitude boundary layer and lower troposphere, namely changes in the midlatitude tropospheric jet and associated transient eddies during winter and large scale convective motions over midlatitudes during summer.

  14. THE BUTTERFLY EFFECT IN THE EXTREME-MASS RATIO INSPIRAL PROBLEM

    SciTech Connect

    Amaro-Seoane, Pau; Brem, Patrick; Cuadra, Jorge; Armitage, Philip J. E-mail: pbrem@ari.uni-heidelberg.de E-mail: pja@jilau1.colorado.edu

    2012-01-10

    Measurements of gravitational waves from the inspiral of a stellar-mass compact object into a massive black hole are unique probes to test general relativity (GR) and massive black hole (MBH) properties, as well as the stellar distribution about these holes in galactic nuclei. Current data analysis techniques can provide us with parameter estimation with very narrow errors. However, an extreme-mass ratio inspiral (EMRI) is not a two-body problem, since other stellar bodies orbiting nearby will influence the capture orbit. Any deviation from the isolated inspiral will induce a small, though observable, deviation from the idealized waveform which could be misinterpreted as a failure of GR. Based on conservative analysis of mass segregation in a Milky-Way-like nucleus, we estimate that the possibility that another star has a semimajor axis comparable to that of the EMRI is non-negligible, although probably very small. This star introduces an observable perturbation in the orbit in the case in which we consider only loss of energy via gravitational radiation. When considering the two first-order non-dissipative post-Newtonian contributions (the periapsis shift of the orbit), the evolution of the orbital elements of the EMRI turns out to be chaotic in nature. The implications of this study are twofold. From the one side, the application to testing GR and measuring MBH parameters with the detection of EMRIs in galactic nuclei with a millihertz mission will be even more challenging than believed. From the other side, this behavior could in principle be used as a signature of mass segregation in galactic nuclei.

  15. Realistic mass ratio magnetic reconnection simulations with the Multi Level Multi Domain method

    NASA Astrophysics Data System (ADS)

    Innocenti, Maria Elena; Beck, Arnaud; Lapenta, Giovanni; Markidis, Stefano

    2014-05-01

    Space physics simulations with the ambition of realistically representing both ion and electron dynamics have to be able to cope with the huge scale separation between the electron and ion parameters while respecting the stability constraints of the numerical method of choice. Explicit Particle In Cell (PIC) simulations with realistic mass ratio are limited in the size of the problems they can tackle by the restrictive stability constraints of the explicit method (Birdsall and Langdon, 2004). Many alternatives are available to reduce such computation costs. Reduced mass ratios can be used, with the caveats highlighted in Bret and Dieckmann (2010). Fully implicit (Chen et al., 2011a; Markidis and Lapenta, 2011) or semi implicit (Vu and Brackbill, 1992; Lapenta et al., 2006; Cohen et al., 1989) methods can bypass the strict stability constraints of explicit PIC codes. Adaptive Mesh Refinement (AMR) techniques (Vay et al., 2004; Fujimoto and Sydora, 2008) can be employed to change locally the simulation resolution. We focus here on the Multi Level Multi Domain (MLMD) method introduced in Innocenti et al. (2013) and Beck et al. (2013). The method combines the advantages of implicit algorithms and adaptivity. Two levels are fully simulated with fields and particles. The so called "refined level" simulates a fraction of the "coarse level" with a resolution RF times bigger than the coarse level resolution, where RF is the Refinement Factor between the levels. This method is particularly suitable for magnetic reconnection simulations (Biskamp, 2005), where the characteristic Ion and Electron Diffusion Regions (IDR and EDR) develop at the ion and electron scales respectively (Daughton et al., 2006). In Innocenti et al. (2013) we showed that basic wave and instability processes are correctly reproduced by MLMD simulations. In Beck et al. (2013) we applied the technique to plasma expansion and magnetic reconnection problems. We showed that notable computational time savings

  16. Colloquium: Search for a drifting proton-electron mass ratio from H2

    NASA Astrophysics Data System (ADS)

    Ubachs, W.; Bagdonaite, J.; Salumbides, E. J.; Murphy, M. T.; Kaper, L.

    2016-04-01

    An overview is presented of the H2 quasar absorption method to search for a possible variation of the proton-electron mass ratio μ =mp/me on a cosmological time scale. The method is based on a comparison between wavelengths of absorption lines in the H2 Lyman and Werner bands as observed at high redshift with wavelengths of the same lines measured at zero redshift in the laboratory. For such comparison sensitivity coefficients to a relative variation of μ are calculated for all individual lines and included in the fitting routine deriving a value for Δ μ /μ . Details of the analysis of astronomical spectra, obtained with large 8-10 m class optical telescopes, equipped with high-resolution echelle grating based spectrographs, are explained. The methods and results of the laboratory molecular spectroscopy of H2, in particular, the laser-based metrology studies for the determination of rest wavelengths of the Lyman and Werner band absorption lines, are reviewed. Theoretical physics scenarios delivering a rationale for a varying μ are discussed briefly, as well as alternative spectroscopic approaches to probe variation of μ , other than the H2 method. Also a recent approach to detect a dependence of the proton-to-electron mass ratio on environmental conditions, such as the presence of strong gravitational fields, are highlighted. Currently some 56 H2 absorption systems are known and listed. Their usefulness to detect μ variation is discussed, in terms of column densities and brightness of background quasar sources, along with future observational strategies. The astronomical observations of ten quasar systems analyzed so far set a constraint on a varying proton-electron mass ratio of |Δ μ /μ |<5 ×1 0-6 (3 σ ), which is a null result, holding for redshifts in the range z =2.0 - 4.2 . This corresponds to look-back times of (10 - 12.4 )×109 years into cosmic history. Attempts to interpret the results from these ten H2 absorbers in terms of a spatial

  17. Photometric Analysis of a Rare, EB Extreme Mass Ratio Binary, V409 Hydrae

    NASA Astrophysics Data System (ADS)

    Labadorf, Christa; Samec, R. G.; Figg, E. R.; Faulkner, D. R.; VanHamme, W.

    2009-01-01

    We present a preliminary analysis of an EB Extreme Mass Ratio eclipsing binary, V409 Hydrae, based on observations taken at the National Undergraduate Research Observatory (NURO) and the Southeastern Association for Research in Astronomy (SARA) in fall 2007 and spring 2008. Light curves, a period study and a synthetic light curve solution are presented for this variable which was recently reclassified by ROTSE as an eclipsing binary (2006, IBVS 5699). Our CCD observations of V409 Hya [NSV4399, GSC230 1604, S9609 Hya, α(2000) = 09h 10m 09.575s, δ(2000) = +03o 44’ 34.42"] were taken on 27-31 September, 2007 at Lowell Observatory with the 0.81-m reflector and 19 February, 12 and 15 March and 19 April, 2008 via remote observing from Kitt Peak. Standard UBVRcIc Johnson-Cousins filters were used. V409 Hya may be considered an AW UMa-type system. Notably, it is an extreme mass ratio, high fill-out, contact binary with unequal eclipse depths. It cannot remain long in such a configuration. We suspect that spots are responsible for this apparently unusual state. The eclipse duration is 68 minutes, while the primary and secondary amplitudes are only 0.5 and 0.4 in V. Mean times of eclipse were calculated: HJD Min I = 2454516.77135(±0.00128), 2454576.7524(±0.0027), HJD Min II = 2454466.9411(±0.0035), 2454517.0064(±0.0049), 2454538.7236(±0.0046). These, the epoch by ROTSE (2006, IBVS 5699) and the epoch calculated by the Wilson code, yielded the following ephemeris: HJD Hel Min I =2451553.30685(±.0.00287)d + 0.4722649(±0.0000005)E. Our unspotted Wilson code solution yielded a mass ratio of only 0.1991(±0.0005), an inclination of 89.2(±0.6)o, component temperatures of 6500 and 6279(±5) K, and a large fill-out of 63%. Other results of our photometric analyses will be presented. We wish to thank NURO for observing time, as well as NASA and the American Astronomical Society for their support in paying for travel and publication expenses.

  18. Accurate age scale of the Dome Fuji ice core, Antarctica from O2/N2 ratio of trapped air

    NASA Astrophysics Data System (ADS)

    Kawamura, K.; Aoki, S.; Nakazawa, T.; Suzuki, K.; Parrenin, F.

    2012-04-01

    Chronology of the first Dome Fuji deep ice core (core length: 2,500 m, ice thickness: 3,035 m) for the age range from 80 kyr to 340 kyr ago was established by orbital tuning of measured O2/N2 ratios in trapped air to local summer insolation, with precision better than about 2,000 years (Kawamura et al., 2007). The O2/N2 ratios found in polar ice cores are slightly lower than the atmospheric ratio because of size-dependent molecular fractionation during bubble close-off. The magnitude of this gas fractionation is believed to be governed by the magnitude of snow metamorphism when the layer was originally at the surface, which in turn is controlled by local summer insolation (Fujita et al., 2009). A strong advantage of the O2/N2 chronology is that there is no need to assume a lag between climatic records in the ice core and orbital forcings, becacuse O2/N2 ratios record local insolation through physical processes. Accuracy of the chronology was validated by comparing the O2/N2 chronology with U-Th radiometric chronology of speleothem records (Cheng et al., 2009) for the ends of Terminations II, III and IV, as well as several large climatic events, for which both ice-core CH4 and speleothem δ18O (a proxy for precipitation) show abrupt shifts as seen in the last glacial period. All ages from O2/N2 and U-Th chronology agreed with each other within ~2,000 yr. The O2/N2 chronology permits comparisons between Antarctic climate, greenhouse gases, astronomically calculated orbital parameters, and radiometrically-dated sea level and monsoon records. Here, we completed the measurements of O2/N2 ratios of the second Dome Fuji ice core, which reached bedrock, for the range from 2,400 to 3,028 m (320 - 700 kyr ago) at approximately 2,000-year time resolution. We made significant improvements in ice core storage practices and mass spectrometry. In particular, the ice core samples were stored at about -50 ° C until the air extraction, except during short periods of transportation

  19. THE MASS DISTRIBUTION AND M/L RATIOS IN NGC 5953/5954

    SciTech Connect

    Hernández Toledo, H. M.; Moreno, E.; García-Barreto, J. A.

    2013-11-01

    In this first paper, we combine a structural analysis of the near-IR surface brightness profiles and [N II] rotation curves for the galaxies in the pair NGC 5953/5954 to model the mass distribution in each member by using two independent axisymmetric analytical mass models: (1) a standard model given by the sum of a spherical bulge with the Sérsic law, a stellar exponential disk, and a cold dark matter halo represented by the improved fitting formula of Navarro et al.; and (2) a simple model given by the sum of a spherical bulge, a finite oblate spheroid representing the disk, and a spherical dark halo, all three mass components with simple density laws. In our surface brightness fits, a central luminous source is considered in both galaxies. We obtained K-band M/L ratios, Y {sub D}, Y {sub B}, for the disks and bulges, and total masses for each mass component in both galaxies. With the standard model we find in NGC 5953, (Y {sub D},Y {sub B}) = (0.29{sub -0.29}{sup +1}, 0.37 ± 0.03) M {sub ☉}/L {sub ☉}, and in NGC 5954, (Y {sub D},Y {sub B}) = (0.88 ± 0.18, 0.21 ± 0.09) M {sub ☉}/L {sub ☉}. Corresponding values found with the simple model are (Y {sub D},Y {sub B}) = (1.41 ± 0.15, 0.29 ± 0.04) M {sub ☉}/L {sub ☉} and (Y {sub D},Y {sub B}) = (0.51 ± 0.05, 0.52{sub -0.12}{sup +0.23}) M {sub ☉}/L {sub ☉}. Our M/L estimates are compared with predictions from other methods in the literature, finding reasonable agreement. The dark halos estimated using the simple model have a small mass, of the order of 10{sup 7} M {sub ☉}, within the maximum distance in the rotation velocity data.

  20. The Mass Distribution and M/L Ratios in NGC 5953/5954

    NASA Astrophysics Data System (ADS)

    Hernández Toledo, H. M.; Moreno, E.; García-Barreto, J. A.

    2013-11-01

    In this first paper, we combine a structural analysis of the near-IR surface brightness profiles and [N II] rotation curves for the galaxies in the pair NGC 5953/5954 to model the mass distribution in each member by using two independent axisymmetric analytical mass models: (1) a standard model given by the sum of a spherical bulge with the Sérsic law, a stellar exponential disk, and a cold dark matter halo represented by the improved fitting formula of Navarro et al. and (2) a simple model given by the sum of a spherical bulge, a finite oblate spheroid representing the disk, and a spherical dark halo, all three mass components with simple density laws. In our surface brightness fits, a central luminous source is considered in both galaxies. We obtained K-band M/L ratios, Upsilon D , Upsilon B , for the disks and bulges, and total masses for each mass component in both galaxies. With the standard model we find in NGC 5953, (Upsilon D ,Upsilon B ) = (0.29_{-0.29}^{+1}, 0.37 ± 0.03) M ⊙/L ⊙, and in NGC 5954, (Upsilon D ,Upsilon B ) = (0.88 ± 0.18, 0.21 ± 0.09) M ⊙/L ⊙. Corresponding values found with the simple model are (Upsilon D ,Upsilon B ) = (1.41 ± 0.15, 0.29 ± 0.04) M ⊙/L ⊙ and (Upsilon D ,Upsilon B ) = (0.51 ± 0.05, 0.52_{-0.12}^{+0.23}) M ⊙/L ⊙. Our M/L estimates are compared with predictions from other methods in the literature, finding reasonable agreement. The dark halos estimated using the simple model have a small mass, of the order of 107 M ⊙, within the maximum distance in the rotation velocity data. Based on data obtained at the 2.1 m telescope of the Observatorio Astronómico Nacional, San Pedro Mártir, Baja California, México, operated by the Instituto de Astronomía, UNAM.

  1. Cosmological Constraints from Galaxy Clustering and the Mass-to-number Ratio of Galaxy Clusters

    NASA Astrophysics Data System (ADS)

    Tinker, Jeremy L.; Sheldon, Erin S.; Wechsler, Risa H.; Becker, Matthew R.; Rozo, Eduardo; Zu, Ying; Weinberg, David H.; Zehavi, Idit; Blanton, Michael R.; Busha, Michael T.; Koester, Benjamin P.

    2012-01-01

    We place constraints on the average density (Ω m ) and clustering amplitude (σ8) of matter using a combination of two measurements from the Sloan Digital Sky Survey: the galaxy two-point correlation function, wp (rp ), and the mass-to-galaxy-number ratio within galaxy clusters, M/N, analogous to cluster M/L ratios. Our wp (rp ) measurements are obtained from DR7 while the sample of clusters is the maxBCG sample, with cluster masses derived from weak gravitational lensing. We construct nonlinear galaxy bias models using the Halo Occupation Distribution (HOD) to fit both wp (rp ) and M/N for different cosmological parameters. HOD models that match the same two-point clustering predict different numbers of galaxies in massive halos when Ω m or σ8 is varied, thereby breaking the degeneracy between cosmology and bias. We demonstrate that this technique yields constraints that are consistent and competitive with current results from cluster abundance studies, without the use of abundance information. Using wp (rp ) and M/N alone, we find Ω0.5 m σ8 = 0.465 ± 0.026, with individual constraints of Ω m = 0.29 ± 0.03 and σ8 = 0.85 ± 0.06. Combined with current cosmic microwave background data, these constraints are Ω m = 0.290 ± 0.016 and σ8 = 0.826 ± 0.020. All errors are 1σ. The systematic uncertainties that the M/N technique are most sensitive to are the amplitude of the bias function of dark matter halos and the possibility of redshift evolution between the SDSS Main sample and the maxBCG cluster sample. Our derived constraints are insensitive to the current level of uncertainties in the halo mass function and in the mass-richness relation of clusters and its scatter, making the M/N technique complementary to cluster abundances as a method for constraining cosmology with future galaxy surveys.

  2. A Lagrangian Model to Predict the Modification of Near-Surface Scalar Mixing Ratios and Air-Water Exchange Fluxes in Offshore Flow

    NASA Astrophysics Data System (ADS)

    Rowe, Mark D.; Perlinger, Judith A.; Fairall, Christopher W.

    2011-07-01

    A model was developed to predict the modification with fetch in offshore flow of mixing ratio, air-water exchange flux, and near-surface vertical gradients in mixing ratio of a scalar due to air-water exchange. The model was developed for planning and interpretation of air-water exchange flux measurements in the coastal zone. The Lagrangian model applies a mass balance over the internal boundary layer (IBL) using the integral depth scale approach, previously applied to development of the nocturnal boundary layer overland. Surface fluxes and vertical profiles in the surface layer were calculated using the NOAA COARE bulk algorithm and gas transfer model (e.g., Blomquist et al. 2006, Geophys Res Lett 33:1-4). IBL height was assumed proportional to the square root of fetch, and estimates of the IBL growth rate coefficient, α, were obtained by three methods: (1) calibration of the model to a large dataset of air temperature and humidity modification over Lake Ontario in 1973, (2) atmospheric soundings from the 2004 New England Air Quality Study and (3) solution of a simplified diffusion equation and an estimate of eddy diffusivity from Monin-Obukhov similarity theory (MOST). Reasonable agreement was obtained between the calibrated and MOST values of α for stable, neutral, and unstable conditions, and estimates of α agreed with previously published parametrizations that were valid for the stable IBL only. The parametrization of α provides estimates of IBL height, and the model estimates modification of scalar mixing ratio, fluxes, and near-surface gradients, under conditions of coastal offshore flow (0-50 km) over a wide range in stability.

  3. Charon/Pluto Mass Ratio Obtained with HST CCD Observations in 1991 and 1993

    NASA Technical Reports Server (NTRS)

    Null, George W.

    1995-01-01

    We have analyzed Hubble Space Telescope wide field camera observations of Pluto, Charon, and a reference star, acquired in 1991 and 1993, to observe Pluto's barycentric motion and determine the Charon/Pluto mass ratio, q = 0.1237 +/-0.0081, with 6.5% accuracy. Solution values for Charon orbital elements include the semimajor axis, a = 19662 +/-81 km; inclination, i = 96.57 +/-0.24 deg; eccentricity, e = 0.0072 +/-0.0067; longitude of periapsis, w = 2 +/-35 deg; and mean longitude, l = 123.58 +/-0.43 deg. These elements are referred to the J2000 Earth equator and equinox at epoch JED 2446600.5.

  4. Stringent null constraint on cosmological evolution of the proton-to-electron mass ratio.

    PubMed

    King, Julian A; Webb, John K; Murphy, Michael T; Carswell, Robert F

    2008-12-19

    We present a strong constraint on variation of the proton-to-electron mass ratio mu over cosmological time scales using molecular hydrogen transitions in optical quasar spectra. Using high quality spectra of quasars Q0405-443, Q0347-383, and Q0528-250, variation in micro relative to the present day value is limited to Deltamicro/micro=(2.6+/-3.0)x10;{-6}. We reduce systematic errors compared to previous works by substantially improving the spectral wavelength calibration method and by fitting absorption profiles to the forest of hydrogen Lyman alpha transitions surrounding each H2 transition. Our results are consistent with no variation, and inconsistent with a previous approximately 4sigma detection of mu variation involving Q0405-443 and Q0347-383. If the results of this work and those suggesting that alpha may be varying are both correct, then this would tend to disfavor certain grand unification models. PMID:19113692

  5. Measurement and simulation of jet mass caused by a high-aspect ratio pertubation

    SciTech Connect

    Keiter, Paul A; Cooley, James; Kyrala, George; Wilson, Doug; Blue, Brent; Edwards, John; Robey, Harry; Spears, Brian

    2009-01-01

    Inertial confinement fusion (ICF) capsule performance can be negatively impacted by the presence of hydrodynamic instabilities. To perform a gas fill on an ICF capsule current plans involve drilling a small hole and inserting a fill tube to inject the gas mixture into the capsule. This introduces a perturbation on the capsule, which can seed hydrodynamic instabilities. The small hole can cause jetting of the shell material into the gas, which might adversely affect the capsule performance. We have performed simulations and experiments to study the hydrodynamic evolution of jets from high-aspect ratio holes, such as the fill tube hole. Although simulations using cold materials over predict the amount of mass in the jet, when a reasonable amount of preheat (< 1 eV) is introduced, the simulations are in better agreement with the experiment.

  6. Measurement and simulation of jet mass caused by a high-aspect ratio hole perturbation

    SciTech Connect

    Keiter, Paul A; Cooley, James H; Wilson, D C; Kyrala, George A; Blue, Brent E; Edwards, J; Elliott, James B; Robey, H F; Spears, B

    2009-01-01

    Inertial confinement fusion (ICF) capsule performance can be negatively impacted by the presence of hydrodynamic instabilities. To perform a gas fill on an ICF capsule, current plans involve drilling a small hole and inserting a fill tube to inject the gas mixture into the capsule. This introduces a perturbation on the capsule, which can seed hydrodynamic instabilities. The small hole can cause jetting of the shell material into the gas, which might adversely affect the capsule performance. We have performed simulations and experiments to study the hydrodynamic evolution of jets from high-aspect ratio holes, such as the fill tube hole. Although simulations using cold materials overpredict the amount of mass in the jet, when a reasonable amount of preheat (<1 eV) is introduced, the simulations are in better agreement with the experiment.

  7. Nonlinear oscillations and waves in an arbitrary mass ratio cold plasma

    SciTech Connect

    Verma, Prabal Singh

    2011-12-15

    It is well known that nonlinear standing oscillations in an arbitrary mass ratio cold plasma always phase mix away. However, there exist nonlinear electron-ion traveling wave solutions, which do not exhibit phase mixing because they have zero ponderomotive force. The existence of these waves has been demonstrated using a perturbation method. Moreover, it is shown that cold plasma BGK waves [Albritton et al., Nucl. Fusion 15, 1199 (1975)] phase mix away if ions are allowed to move and the scaling of phase mixing is found to be different from earlier work [Sengupta et al., Phys. Rev. Lett. 82, 1867 (1999)]. Phase mixing of these waves has been further verified in 1-D particle in cell simulation.

  8. STELLAR MASS-TO-LIGHT RATIOS FROM GALAXY SPECTRA: HOW ACCURATE CAN THEY BE?

    SciTech Connect

    Gallazzi, Anna; Bell, Eric F. E-mail: ericbell@umich.edu

    2009-12-01

    Stellar masses play a crucial role in the exploration of galaxy properties and the evolution of the galaxy population. In this paper, we explore the minimum possible uncertainties in stellar mass-to-light ratios (M {sub *}/L) from the assumed star formation history (SFH) and metallicity distribution, with the goals of providing a minimum set of requirements for observational studies. We use a large Monte Carlo library of SFHs to study as a function of galaxy spectral type and signal-to-noise ratio (S/N) the statistical uncertainties of M {sub *}/L values using either absorption-line data or broadband colors. The accuracy of M {sub *}/L estimates can be significantly improved by using metal-sensitive indices in combination with age-sensitive indices, in particular for galaxies with intermediate-age or young stellar populations. While M {sub *}/L accuracy clearly depends on the spectral S/N, there is no significant gain in improving the S/N much above 50 pixel{sup -1} and limiting uncertainties of {approx}0.03 dex are reached. Assuming that dust is accurately corrected or absent and that the redshift is known, color-based M {sub *}/L estimates are only slightly more uncertain than spectroscopic estimates (at comparable spectroscopic and photometric quality), but are more easily affected by systematic biases. This is the case in particular for galaxies with bursty SFHs (high H{delta} {sub A} at fixed D4000 {sub n}), the M {sub *}/L of which cannot be constrained any better than {approx}0.15 dex with any indicators explored here. Finally, we explore the effects of the assumed prior distribution in SFHs and metallicity, finding them to be higher for color-based estimates.

  9. An efficient numerical calculation of gravitational waves from extreme mass ratio inspirals

    NASA Astrophysics Data System (ADS)

    Fujita, Ryuichi; Hikida, Wataru; Tagoshi, Hideyuki

    2009-03-01

    Gravitational waves from extreme mass ratio inspirals are one of the important sources of LISA. We should calculate these waves so accurately that we can extract physical information of source by data analysis. Recently, we developed an efficient numerical method to compute gravitational waves from binary systems in which a point particle moves in circular orbits on the equatorial plane of the black hole. In this paper, we apply this method to compute gravitational waves from binary systems in which a point particle moves in general bound geodesic orbits of the black hole. We check the accuracy of our code using spherical symmetry of Schwarzschild black hole such that energy flux radiated by a point particle is independent of the inclination angle from the equatorial plane of black hole. We find that the accuracy of our code may be limited only by truncation of l, k and n -modes, where l is the degree of the spin-weighted spheroidal harmonics, and k and n are harmonics of the polar and radial motion, respectively. Then we evaluate the rate of change of three constants of motion, energy, angular momentum and the Carter constant, due to the emission of gravitational waves from a particle around Kerr black hole. This is the first time to compute the rate of change of the Carter constant using the adiabatic approximation. We also show that we can calculate gravitational waves accurately even in the case of high eccentric orbits. In this work, we truncate l mode up to 20 and estimated that relative accuracy of our numerical results are better than 10-5 even in the high eccentric case, e = 0.9. Our numerical code may be useful to make templates of extreme mass ratio inspirals.

  10. Fabrication of organic solar cells with design blend P3HT: PCBM variation of mass ratio

    NASA Astrophysics Data System (ADS)

    Supriyanto, Agus; Mustaqim, Amrina; Agustin, Maya; Ramelan, Ari H.; Suyitno; Septa Rosa, Erlyta; Yofentina; Nurosyid, Fahru

    2016-02-01

    Organic solar cells of FTO/PEDOT: PSS/P3HT: PCBM/Al has been fabricated, and its performance has been tested in dark and under various illumination of light intensity 1000 W/m2. The active materials used in this study are poly (3- hexylthiophene) (P3HT) and [6, 6]-phenyl-C61-butyric acid methyl ester (PCBM). P3HT is the donor while PCBM acts as an acceptor. Variation of PCBM and P3HT are 1:1, 1:2, 1:3, 1:4 and 1:5. P3HT: PCBM was mixed by chlorobenzene solvents. The mixing was done by using the ultrasonic cleaner. The absorbance characterization using by UV-Visible Spectrometer Lambda 25 instrument and I-V characterization has been tested using a set of 2602A Keithley instrument. Absorbance characterization shows that two peaks are formed. The first peak in the range of 300 to 350 nm which is a range of PCBM and the second peak range from 450 to 600 nm which is a range of P3HT. As the mass ratio increases, the second peak of P3HT increases while the first peak does not change. The gap energy estimated by the Tauc method is 2.0 eV. I-V characterization of the efficiency was obtained. The efficiency of sample 1, 2, 3, 4, and 5 are 5.80x10-2%; 6.46x10-2%; 7.72x10-2%; 8.25x10-2% and 9.81x10-2%, respectively. The highest value of efficiency was obtained at mass ratio 1:5.

  11. Extreme- and intermediate-mass ratio inspirals in dynamical Chern-Simons modified gravity

    SciTech Connect

    Sopuerta, Carlos F.; Yunes, Nicolas

    2009-09-15

    Chern-Simons modified gravity is a four-dimensional, effective theory that descends both from string theory and loop quantum gravity, and that corrects the Einstein-Hilbert action by adding the product of a scalar field and the parity-violating, Pontryagin density. The Chern-Simons modification deforms the gravitational field of spinning black holes, which is now described by a modified Kerr geometry whose multipole moments deviate from the Kerr ones only at the fourth multipole l=4. This paper investigates possible signatures of this theory in the gravitational-wave emission produced in the inspiral of stellar compact objects into massive black holes, both for intermediate- and extreme-mass ratios. We use the semirelativistic approximation, where the trajectory of the small compact object is modeled via geodesics of the massive black hole geometry, while the gravitational waveforms are obtained from a multipolar decomposition of the radiative field. The main Chern-Simons corrections to the waveforms arise from modifications to the geodesic trajectories, which in turn are due to changes to the massive black hole geometry, and manifest themselves as an accumulating dephasing relative to the general relativistic case. We also explore the propagation and the stress-energy tensor of gravitational waves in this theory, using the short-wavelength approximation. We find that, although this tensor has the same form as in general relativity, the energy and angular momentum balance laws are indeed modified through the stress-energy tensor of the Chern-Simons scalar field. These balance laws could be used to describe the inspiral through adiabatic changes in the orbital parameters, which in turn would enhance the dephasing effect. Gravitational-wave observations of intermediate- or extreme-mass-ratio inspirals with advanced ground detectors or with the Laser Interferometer Space Antenna could use such dephasing to test the dynamical theory to unprecedented levels, thus

  12. Improved analytic extreme-mass-ratio inspiral model for scoping out eLISA data analysis

    NASA Astrophysics Data System (ADS)

    Chua, Alvin J. K.; Gair, Jonathan R.

    2015-12-01

    The space-based gravitational-wave detector eLISA has been selected as the ESA L3 mission, and the mission design will be finalized by the end of this decade. To prepare for mission formulation over the next few years, several outstanding and urgent questions in data analysis will be addressed using mock data challenges, informed by instrument measurements from the LISA Pathfinder satellite launching at the end of 2015. These data challenges will require accurate and computationally affordable waveform models for anticipated sources such as the extreme-mass-ratio inspirals (EMRIs) of stellar-mass compact objects into massive black holes. Previous data challenges have made use of the well-known analytic EMRI waveforms of Barack and Cutler, which are extremely quick to generate but dephase relative to more accurate waveforms within hours, due to their mismatched radial, polar and azimuthal frequencies. In this paper, we describe an augmented Barack-Cutler model that uses a frequency map to the correct Kerr frequencies, along with updated evolution equations and a simple fit to a more accurate model. The augmented waveforms stay in phase for months and may be generated with virtually no additional computational cost.

  13. Analytical high-order post-Newtonian expansions for spinning extreme mass ratio binaries

    NASA Astrophysics Data System (ADS)

    Kavanagh, Chris; Ottewill, Adrian C.; Wardell, Barry

    2016-06-01

    We present an analytic computation of Detweiler's redshift invariant for a point mass in a circular orbit around a Kerr black hole, giving results up to 8.5 post-Newtonian order while making no assumptions on the magnitude of the spin of the black hole. Our calculation is based on the functional series method of Mano, Suzuki and Takasugi, and employs a rigorous mode-sum regularization prescription based on the Detweiler-Whiting singular-regular decomposition. The approximations used in our approach are minimal; we use the standard self-force expansion to linear order in the mass ratio, and the standard post-Newtonian expansion in the separation of the binary. A key advantage of this approach is that it produces expressions that include contributions at all orders in the spin of the Kerr black hole. While this work applies the method to the specific case of Detweiler's redshift invariant, it can be readily extended to other gauge-invariant quantities and to higher post-Newtonian orders.

  14. The Spectroscopic Binary Mass Ratio in the Young Ophiuchus Triple NTTS 155808-2219

    NASA Astrophysics Data System (ADS)

    Mace, Gregory N.; Prato, L.; Wasserman, L.; Torres, G.; Mathieu, R.

    2009-01-01

    The young triple system NTTS 155808-2219 was initially identified as a single-lined spectroscopic binary with a tertiary component at 0.193 arcseconds. Using high-resolution infrared spectra, acquired with NIRSPEC on Keck II, we measured radial velocities for the secondary in the spectroscopic system. We have also compiled a large number of radial velocity measurements, that span most of the 17 day period, from visible light observations made from 1987 June to 1993 April employing echelle spectrographs on the Multiple Mirror Telescope and the 1.5-m Tillinghast reflector at the F.L. Whipple Observatory, both atop Mount Hopkins in Arizona. By combining visible light and infrared data to compute the orbital solution we determine the mass ratio to be 0.74 ± 0.02. We discuss the consistency of our results with previously published data on this system and the possibility that this system is eclipsing, providing a possible method for the determination of absolute masses.

  15. Enhanced sensitivity to a possible variation of the proton-to-electron mass ratio in ammonia

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

    Numerous accidental near degeneracies exist between the 2 ν2 and ν4 rotation-vibration energy levels of ammonia. Transitions between these two states possess significantly enhanced sensitivity to a possible variation of the proton-to-electron mass ratio μ . Using a robust variational approach to determine the mass sensitivity of the energy levels along with accurate experimental values for the energies, sensitivity coefficients have been calculated for over 350 microwave, submillimeter, and far-infrared transitions up to J =15 for NH143. The sensitivities are the largest found in ammonia to date. One particular transition, although extremely weak, has a sensitivity of T =-16 738 and illustrates the huge enhancement that can occur between close-lying energy levels. More promising however are a set of previously measured transitions with T =-32 to 28. Given the astrophysical importance of ammonia, the sensitivities presented here confirm that NH143 can be used exclusively to constrain a spatial or temporal variation of μ . Thus certain systematic errors which affect the ammonia method can be eliminated. For all transitions analyzed we provide frequency data and Einstein A coefficients to guide future laboratory and astronomical observations.

  16. Biases in the inferred mass-to-light ratio of globular clusters: no need for variations in the stellar mass function

    NASA Astrophysics Data System (ADS)

    Shanahan, Rosemary L.; Gieles, Mark

    2015-03-01

    From a study of the integrated light properties of 200 globular clusters (GCs) in M31, Strader et al. found that the mass-to-light ratios are lower than what is expected from simple stellar population models with a `canonical' stellar initial mass function (IMF), with the discrepancy being larger at high metallicities. We use dynamical multimass models, that include a prescription for equipartition, to quantify the bias in the inferred dynamical mass as the result of the assumption that light follows mass. For a universal IMF and a metallicity-dependent present-day mass function, we find that the inferred mass from integrated light properties systematically underestimates the true mass, and that the bias is more important at high metallicities, as was found for the M31 GCs. We show that mass segregation and a flattening of the mass function have opposing effects of similar magnitude on the mass inferred from integrated properties. This makes the mass-to-light ratio as derived from integrated properties an inadequate probe of the low-mass end of the stellar mass function. There is, therefore, no need for variations in the IMF, nor the need to invoke depletion of low-mass stars, to explain the observations. Finally, we find that the retention fraction of stellar-mass black holes (BHs) is an equally important parameter in understanding the mass segregation bias. We speculatively put forward to idea that kinematical data of GCs can in fact be used to constrain the total mass in stellar-mass BHs in GCs.

  17. Investigating the effect of mixing ratio on molar mass distributions of synthetic polymers determined by MALDI-TOF mass spectrometry using design of experiments.

    PubMed

    Brandt, Heike; Ehmann, Thomas; Otto, Matthias

    2010-11-01

    It is well known that the mixing ratio affects the molar mass distribution of synthetic polymers determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Surely, the molar mixing ratio determines whether a mass spectrum will be obtained or not. However, depending on the mass range, several effects such as multimer formation occur, which might be a source of errors in molar mass distribution calculations. In this study, the effect of mixing ratio was investigated for several synthetic polymers, including polystyrene (PS), poly(dimethylsiloxane) (PDMS), poly(ethylene glycol) (PEG), and poly(methyl methacrylate) (PMMA) using statistical designs of experiments. The 2(3) full factorial design was found to be suitable in the study of more than 1000 samples. The obtained MALDI mass spectra as well as the ANOVA statistics show that the mixing ratio affects the molar mass distribution. The optimal mixing ratio for a defined synthetic polymer depends on the studied combination (matrix, cationization reagent, solvent). PMID:20685132

  18. New developments in high-resolution gas source isotope ratio mass spectrometers

    NASA Astrophysics Data System (ADS)

    Clog, M. D.; Ellam, R. M.; Hilkert, A.; Schwieters, J. B.; Hamilton, D.

    2015-12-01

    Gas source isotope ratio mass spectrometry (IRMS) is one of the main tools for the study of the isotopic compositions of light elements, extended in the last 10 years to the measurements of molecules bearing several rare isotopes (e.g., clumped isotopes of CO2) as well as position-specific isotopic substitutions in a few choice analytes (e.g., in N2O). Measuring those low-abundance species creates several technical challenges, with the main one being the presence of numerous isobaric interferences. Those can come either from contaminants (background gases present in the source of the instrument or impurities introduced with the analyte), or unwanted beams created by the analyte itself during the ionization process (for example adducts and fragments). In order to avoid those isobaric species, new high-resolution, double-focusing IRMS have been developed. We present here the capabilities of the production series version of the ThermoFisher Scientific 253 Ultra, which was installed at SUERC in July 2015. The instrument is capable of reaching high mass resolving power (above 40,000) and is similar in design to the Caltech 253 Ultra prototype. The collector array has 9 detector positions, 8 of which are movable. Faraday cups at each detector can be linked to amplifiers with gains ranging from 3.108 to 1012 Ohm (and 1013 Ohm amplifiers being currently developped). There are also 4 ion counters, one of which located behind a retardation lens (RPQ) to limit background noise and improve abundance sensitivity. Additionally, one of the Faraday cup in the new instrument has a very narrow entrance slit, allowing high mass resolving power and high resolution, with a complete separation of the ion beams instead of complex peak shapes corresponding to overlapping ion beams. This will potentially remove the need for adduct lines or peak stripping schemes for analytes like CH4.

  19. Performance and optimization of a combustion interface for isotope ratio monitoring gas chromatography/mass spectrometry.

    PubMed

    Merritt, D A; Freeman, K H; Ricci, M P; Studley, S A; Hayes, J M

    1995-07-15

    Conditions and systems for on-line combustion of effluents from capillary gas chromatographic columns and for removal of water vapor from product streams were tested. Organic carbon in gas chromatographic peaks 15 s wide and containing up to 30 nanomoles of carbon was quantitatively converted to CO2 by tubular combustion reactors, 200 x 0.5 mm, packed with CuO or NiO. No auxiliary source of O2 was required because oxygen was supplied by metal oxides. Spontaneous degradation of CuO limited the life of CuO reactors at T > 850 degrees C. Since NiO does not spontaneously degrade, its use might be favored, but Ni-bound carbon phases form and lead to inaccurate isotopic results at T < 1050 degrees C if gas-phase O2 is not added. For all compounds tested except CH4, equivalent isotopic results are provided by CuO at 850 degrees C, NiO + O2 (gas-phase mole fraction, 10(-3)) at 1050 degrees C and NiO at 1150 degrees C. The combustion interface did not contribute additional analytical uncertainty, thus observed standard deviations of 13C/12C ratios were within a factor of 2 of shot-noise limits. For combustion and isotopic analyses of CH4, in which quantitative combustion required T approximately 950 degrees C, NiO-based systems are preferred, and precision is approximately 2 times lower than that observed for other analytes. Water must be removed from the gas stream transmitted to the mass spectrometer or else protonation of CO2 will lead to inaccuracy in isotopic analyses. Although thresholds for this effect vary between mass spectrometers, differential permeation of H2O through Nafion tubing was effective in both cases tested, but the required length of the Nafion membrane was 4 times greater for the more sensitive mass spectrometer. PMID:11536720

  20. Performance and optimization of a combustion interface for isotope ratio monitoring gas chromatography/mass spectrometry

    NASA Technical Reports Server (NTRS)

    Merritt, D. A.; Freeman, K. H.; Ricci, M. P.; Studley, S. A.; Hayes, J. M.

    1995-01-01

    Conditions and systems for on-line combustion of effluents from capillary gas chromatographic columns and for removal of water vapor from product streams were tested. Organic carbon in gas chromatographic peaks 15 s wide and containing up to 30 nanomoles of carbon was quantitatively converted to CO2 by tubular combustion reactors, 200 x 0.5 mm, packed with CuO or NiO. No auxiliary source of O2 was required because oxygen was supplied by metal oxides. Spontaneous degradation of CuO limited the life of CuO reactors at T > 850 degrees C. Since NiO does not spontaneously degrade, its use might be favored, but Ni-bound carbon phases form and lead to inaccurate isotopic results at T < 1050 degrees C if gas-phase O2 is not added. For all compounds tested except CH4, equivalent isotopic results are provided by CuO at 850 degrees C, NiO + O2 (gas-phase mole fraction, 10(-3)) at 1050 degrees C and NiO at 1150 degrees C. The combustion interface did not contribute additional analytical uncertainty, thus observed standard deviations of 13C/12C ratios were within a factor of 2 of shot-noise limits. For combustion and isotopic analyses of CH4, in which quantitative combustion required T approximately 950 degrees C, NiO-based systems are preferred, and precision is approximately 2 times lower than that observed for other analytes. Water must be removed from the gas stream transmitted to the mass spectrometer or else protonation of CO2 will lead to inaccuracy in isotopic analyses. Although thresholds for this effect vary between mass spectrometers, differential permeation of H2O through Nafion tubing was effective in both cases tested, but the required length of the Nafion membrane was 4 times greater for the more sensitive mass spectrometer.

  1. Temperature-programmed high-performance liquid chromatography coupled to isotope ratio mass spectrometry.

    PubMed

    Godin, Jean-Philippe; Hopfgartner, Gérard; Fay, Laurent

    2008-09-15

    The utility of liquid chromatography coupled to the isotope ratio mass spectrometry technique (LC-IRMS) has already been established through a variety of successful applications. However, the analytical constraint related to the use of aqueous mobile phases limits the LC separation mechanism. We report here a new strategy for high-precision (13)C isotopic analyses based on temperature-programmed LC-IRMS using aqueous mobile phases. Under these conditions, the isotopic precision and accuracy were studied. On one hand, experiments were carried out with phenolic acids using isothermal LC conditions at high temperature (170 degrees C); on the other hand, several experiments were performed by ramping the temperature, as conventionally used in a gas chromatography-based method with hydrosoluble fatty acids and pulses of CO 2 reference gas. In isothermal conditions at 170 degrees C, despite the increase of the CO 2 background, p-coumaric acid and its glucuronide conjugate gave reliable isotopic ratios compared to flow injection analysis-isotopic ratio mass spectrometry (FIA-IRMS) analyses (isotopic precision and accuracy are lower than 0.3 per thousand). On the opposite, for its sulfate conjugate, the isotopic accuracy is affected by its coelution with p-coumaric acid. Not surprisingly, this study also demonstrates that at high temperature (170 degrees C), a compound eluting with long residence time (i.e., ferulic acid) is degraded, affecting thus the delta (13)C (drift of 3 per thousand) and the peak area (compared to FIA-IRMS analysis at room temperature). Quantitation is also reported in isothermal conditions for p-coumaric acid in the range of 10-400 ng/mL and with benzoic acid as an internal standard. For temperature gradient LC-IRMS, in the area of the LC gradient (set up at 20 degrees C/min), the drift of the background observed produces a nonlinearity of SD (delta (13)C) approximately 0.01 per thousand/mV. To circumvent this drift, which impacts severely the

  2. Analysis of the Extreme Mass Ratio, High Contact Eclipsing Binary, V802 Aquilae

    NASA Astrophysics Data System (ADS)

    Samec, R. G.; Martin, M. W.; Faulkner, D. R.

    2004-05-01

    We present our observations and initial analysis of BVRI light curves of the solar type, high contact binary, V802 Aquilae [GSC 5119 948, α (2000) = 18h 58m 54.82s, δ (2000) = -03° 01' 11.5"]. The observations were taken on the evenings of 5, 6 and 8 June 2002, by RGS and DRF with the 0.9-m reflector at CTIO. Standard UBVRcIc filters were used. We took from 138 to 148 observations in each BVRI pass band and about 100 in U. Mean epochs of minimum light for one primary eclipse, HJD = 2452431.82156 (81) as well as two secondary eclipses 2452434.89764 (11) and 2452432.75617 (21) were calculated. We calculated the following linear ephemeris: J.D. Hel Min I = 2450300.43417 (69) + 0.26769479 (11) d*E. (2) The light curves are shallow (0.35 mag in V) yet show a broad time of constant light (width about 0.1 phase) in the secondary eclipse. Its depressed primary maxima (about 0.06 mag in B) suggest the presence of heavy spot activity. Our Wilson code BVRI simultaneous solution of the instrumental magnitude light curves yields a mass ratio of M2/M1 = 0.16, and a fill-out 32.7 %. The temperature difference is T2-T1 = 136 K with the tiny secondary component having the higher mean surface temperature. A 20.2° cool spot was modeled on the primary component. Its longitude, co-latitude and temperature factor were 281° , 67° , and 0.915 respectively. Further results are presented. The system is a part of a rare group of binaries with a very low mass secondary and high mass ratio that are near a phase of final coalescence into an FK Comae type star. Much of the work was done by an undergraduate student, MWM. We wish to thank Cerro Tololo InterAmerican Observatory for their allocation of observing time, and the grant from NASA administered by the American Astronomical Society.

  3. Elemental composition of different air masses over Jeju Island, South Korea

    NASA Astrophysics Data System (ADS)

    Kang, Jeongwon; Choi, Man-Sik; Yi, Hi-Il; Jeong, Kap-Sik; Chae, Jung-Sun; Cheong, Chang-Sik

    2013-03-01

    We investigated the characteristics (concentrations and compositional changes) of atmospheric elements in total suspended particulates through source-receptor relationships using cluster analyses to classify air mass back-trajectories arriving at Gosan, Jeju Island, South Korea, from October 2003 to December 2008. Five trajectory clusters were chosen to explain the transport regimes. Continental outflows of natural and anthropogenic aerosols from Asian dust source regions and eastern China during the colder period could increase element concentrations at Gosan. Elemental levels at Gosan decreased in air masses that passed over marine regions (East China Sea, Pacific Ocean/southern side of Kyushu Island in Japan, and East Sea/southern side of South Korea) during the warmer rainy period due to lower source intensity and dilution by the marine air mass. Anthropogenic pollutants were often major components in air masses passing over marine regions. Air mass characterization by elemental concentration and composition revealed that enrichment by non-sea-salt sulfur in the air mass originated from eastern China, indicative of the main sulfur emitter in northeast Asia. The apportionment of V and Ni by principal component analysis as a marker of heavy oil combustion suggested different residence times and deposition rates from other anthropogenic components in the air. Regionally intermediate concentrations of pollutants were found in the atmosphere over the Korean peninsula.

  4. Chiral Signatures of Anthropogenic Semi-Volatile Organic Compounds in Asian, trans- Pacific, and Pacific Northwestern Air Masses

    NASA Astrophysics Data System (ADS)

    Genualdi, S.; Primbs, T.; Bidleman, T.; Jantunen, L.; Simonich, S.

    2006-12-01

    The goal of this research is to use the chiral signatures of Semi-Volatile Organic Compounds (SOCs) to distinguish between new and old sources in Asian, trans-Pacific, and regional air masses. During 2004, a six week air sampling campaign was conducted at a remote site in Okinawa, Japan to determine the chemical composition of Eurasian air masses. During 2003 and 2004, high volume air samples were collected at three different locations in the Pacific Northwest of the United States. These sampling locations were; Mary's Peak Observatory (MPO) located at 1250m in the Oregon Coast Range, Mt. Bachelor located at 2800m in Oregon's Cascade Range, and Cheeka Peak Observatory (CPO) located at 500m in the state of Washington. The air samples consisted of both polyurethane foam and XAD-2 resin to collect the gas phase SOCs, and glass fiber filters to collect the particulate phase SOCs. The samples were extracted using accelerated solvent extraction and enantiomer fractions were determined using GCMS-ECNI with the use of a BGB Analytik chiral column. The chiral SOCs, á-Hexachlorocyclohexane, cis and trans chlordane, heptachlor epoxide, and o'p' DDT, were measured, the enantiomer ratios were determined, and potential new and historical sources of these compounds were identified.

  5. Experimental study of the water-to-air stopping power ratio of monoenergetic carbon ion beams for particle therapy.

    PubMed

    Sánchez-Parcerisa, D; Gemmel, A; Jäkel, O; Parodi, K; Rietzel, E

    2012-06-01

    Reference dosimetry with ionization chambers requires a number of chamber-specific and beam-specific calibration factors. For carbon ion beams, IAEA report TRS-398 yields a total uncertainty of 3% in the determination of the absorbed dose to water, for which the biggest contribution arises from the water-to-air stopping power ratio (s(w, air)), with an uncertainty of 2%. The variation of (s(w, air)) along the treatment field has been studied in several Monte Carlo works presented over the last few years. Their results were, in all cases, strongly dependent on the choice of mean ionization potentials (I-values) for air and water. A smaller dependence of (s(w, air)) with penetration depth was observed. Since a consensus on I(w, air) and I(air) has not yet been reached, the validity of such studies for clinical use cannot be assessed independently. Our approach is based on a direct experimental measurement of water-equivalent thicknesses of different air gaps at different beam energies. A theoretical expression describing the variation of the stopping power ratio with kinetic energy, s(w,air)(E), was derived from the Bethe-Bloch formula and fit to the measured data, yielding a coherent pair of I(w) and I(air) values with I(air)/I(w) = 1.157 ± 0.023. Additionally, the data from five different beam energies were combined in an average value of s(w,air) = 1.132 ± 0.003 (statistical) ± 0.003 (variation over energy range), valid for monoenergetic carbon ion beams at the plateau area of the depth dose distribution. A detailed uncertainty analysis was performed on the data, in order to assess the limitations of the method, yielding an overall standard uncertainty below 1% in s(w,air)(E). Therefore, when properly combined with the appropriate models for the fragment spectra, our experimental work can contribute to narrow the uncertainty margins currently in use in absorbed dose to water determination for dosimetry of carbon ion beam radiotherapy. PMID:22596046

  6. 30 CFR 7.87 - Test to determine the maximum fuel-air ratio.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... the intake air. Where: Ps = dry atmospheric pressure (kPa) Ta = intake air temperature (°C) (ii) The...) The parameter for the laboratory atmospheric factor, fa, shall be: 0.98≤fa≤1.02; (A) The equation...

  7. 30 CFR 7.87 - Test to determine the maximum fuel-air ratio.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... the intake air. Where: Ps = dry atmospheric pressure (kPa) Ta = intake air temperature (°C) (ii) The...) The parameter for the laboratory atmospheric factor, fa, shall be: 0.98≤fa≤1.02; (A) The equation...

  8. 30 CFR 7.87 - Test to determine the maximum fuel-air ratio.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... the intake air. Where: Ps = dry atmospheric pressure (kPa) Ta = intake air temperature (°C) (ii) The...) The parameter for the laboratory atmospheric factor, fa, shall be: 0.98≤fa≤1.02; (A) The equation...

  9. 30 CFR 7.87 - Test to determine the maximum fuel-air ratio.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... the intake air. Where: Ps = dry atmospheric pressure (kPa) Ta = intake air temperature (°C) (ii) The...) The parameter for the laboratory atmospheric factor, fa, shall be: 0.98≤fa≤1.02; (A) The equation...

  10. 30 CFR 7.87 - Test to determine the maximum fuel-air ratio.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... the intake air. Where: Ps = dry atmospheric pressure (kPa) Ta = intake air temperature (°C) (ii) The...) The parameter for the laboratory atmospheric factor, fa, shall be: 0.98≤fa≤1.02; (A) The equation...

  11. The Analysis of PPM Levels of Gases in Air by Photoionization Mass Spectrometry

    ERIC Educational Resources Information Center

    Driscoll, John N.; Warneck, Peter

    1973-01-01

    Discusses analysis of trace gases in air by photoionization mass spectrometer. It is shown that the necessary sensitivity can be obtained by eliminating the UV monochromator and using direct ionization with a hydrogen light source. (JP)

  12. Development of Charge to Mass Ratio Microdetector for Future Mars Mission

    NASA Technical Reports Server (NTRS)

    Chen, Yuan-Lian Albert

    2003-01-01

    The Mars environment comprises a dry, cold and low air pressure atmosphere with low gravity (0.38g) and high resistivity soil. The global dust storms that cover a large portion of Mars are observed often from Earth. This environment provides an ideal condition for turboelectric charging. The extremely dry conditions on the Martian surface have raised concerns that electrostatic charge buildup will not be dissipated easily. If turboelectrically generated charge cannot be dissipated or avoided, then dust will accumulate on charged surfaces and electrostatic discharge may cause hazards for future exploration missions. The low surface on Mars helps to prolong the charge decay on the dust particles and soil. To better understanding the physics of Martian charged dust particles is essential to future Mars missions. We research and design two sensors, velocity/charge sensor and PZT momentum sensors, to measure the velocity distribution, charge distribution and mass distribution of Martian wed dust particles. These sensors are fabricated at NASA Kenney Space Center, Electrostatic and Surface Physics Laboratory. The sensors are calibrated. The momentum sensor is capable to measure 45 pan size particles. The designed detector is very simple, robust, without moving parts, and does not require a high voltage power supply. Two sensors are combined to form the Dust Microdetector - CHAL.

  13. An automated gas chromatography time-of-flight mass spectrometry instrument for the quantitative analysis of halocarbons in air

    NASA Astrophysics Data System (ADS)

    Obersteiner, F.; Bönisch, H.; Engel, A.

    2016-01-01

    We present the characterization and application of a new gas chromatography time-of-flight mass spectrometry instrument (GC-TOFMS) for the quantitative analysis of halocarbons in air samples. The setup comprises three fundamental enhancements compared to our earlier work (Hoker et al., 2015): (1) full automation, (2) a mass resolving power R = m/Δm of the TOFMS (Tofwerk AG, Switzerland) increased up to 4000 and (3) a fully accessible data format of the mass spectrometric data. Automation in combination with the accessible data allowed an in-depth characterization of the instrument. Mass accuracy was found to be approximately 5 ppm in mean after automatic recalibration of the mass axis in each measurement. A TOFMS configuration giving R = 3500 was chosen to provide an R-to-sensitivity ratio suitable for our purpose. Calculated detection limits are as low as a few femtograms by means of the accurate mass information. The precision for substance quantification was 0.15 % at the best for an individual measurement and in general mainly determined by the signal-to-noise ratio of the chromatographic peak. Detector non-linearity was found to be insignificant up to a mixing ratio of roughly 150 ppt at 0.5 L sampled volume. At higher concentrations, non-linearities of a few percent were observed (precision level: 0.2 %) but could be attributed to a potential source within the detection system. A straightforward correction for those non-linearities was applied in data processing, again by exploiting the accurate mass information. Based on the overall characterization results, the GC-TOFMS instrument was found to be very well suited for the task of quantitative halocarbon trace gas observation and a big step forward compared to scanning, quadrupole MS with low mass resolving power and a TOFMS technique reported to be non-linear and restricted by a small dynamical range.

  14. Tissue mass ratios and the reporting of distal lower extremity injuries in varsity athletes at a Canadian University.

    PubMed

    Burkhart, Timothy A; Schinkel-Ivy, Alison; Andrews, David M

    2013-01-01

    The purpose of this preliminary investigation was to determine the relative role of the distal lower extremity tissue masses of varsity athletes in predicting distal lower extremity injury sustained during a competitive season. One hundred male and female varsity athletes (basketball, volleyball, soccer, cross country) completed a questionnaire on general health, physiological, and psychosocial variables, during each sport's respective training camp. A series of anthropometric measurements were used as inputs to distal lower extremity tissue mass prediction equations to calculate lean mass, fat mass, bone mineral content and wobbling mass (lean mass + fat mass) and tissue mass ratios. Athletes were monitored throughout their respective seasons and were instructed to report any distal lower extremity injuries to a certified athletic therapist who was responsible for assessing and confirming the reports. Logistic regression analyses were performed to determine which variables significantly predicted distal lower extremity injury. Mean leg fat mass:bone mass (OR = 1.6, CI = 1.0 - 2.5), and competition surface (rubber OR = 8.5, CI = 1.5 - 47.7; artificial turf OR = 4.0, CI = 0.77 - 22.9) were identified as significant predictors of injury. Overall, tibia bone injuries were significantly associated with the ratio of fat mass:bone mineral content and the surface on which the athletes compete. PMID:23215824

  15. The influence of polarization on box air mass factors for UV/vis nadir satellite observations

    NASA Astrophysics Data System (ADS)

    Hilboll, Andreas; Richter, Andreas; Rozanov, Vladimir V.; Burrows, John P.

    2015-04-01

    Tropospheric abundances of pollutant trace gases like, e.g., NO2, are often derived by applying the differential optical absorption spectroscopy (DOAS) method to space-borne measurements of back-scattered and reflected solar radiation. The resulting quantity, the slant column density (SCD), subsequently has to be converted to more easily interpretable vertical column densities by means of the so-called box air mass factor (BAMF). The BAMF describes the ratio of SCD and VCD within one atmospheric layer and is calculated by a radiative transfer model. Current operational and scientific data products of satellite-derived trace gas VCDs do not include the effect of polarization in their radiative transfer models. However, the various scattering processes in the atmosphere do lead to a distinctive polarization pattern of the observed Earthshine spectra. This study investigates the influence of these polarization patterns on box air mass factors for satellite nadir DOAS measurements of NO2 in the UV/vis wavelength region. NO2 BAMFs have been simulated for a multitude of viewing geometries, surface albedos, and surface altitudes, using the radiative transfer model SCIATRAN. The results show a potentially large influence of polarization on the BAMF, which can reach 10% and more close to the surface. A simple correction for this effect seems not to be feasible, as it strongly depends on the specific measurement scenario and can lead to both high and low biases of the resulting NO2 VCD. We therefore conclude that all data products of NO2 VCDs derived from space-borne DOAS measurements should include polarization effects in their radiative transfer model calculations, or at least include the errors introduced by using linear models in their uncertainty estimates.

  16. Authenticity of carbon dioxide bubbles in French ciders through multiflow-isotope ratio mass spectrometry measurements.

    PubMed

    Gaillard, Laetitia; Guyon, Francois; Salagoïty, Marie-Hélène; Médina, Bernard

    2013-12-01

    A procedure to detect whether carbon dioxide was added to French ciders has been developed. For this purpose, an optimised and simplified method is proposed to determine (13)C/(12)C isotope ratio of carbon dioxide (δ(13)C) in ciders. Three critical steps were checked: (1) influence of atmospheric CO2 remaining in the loaded vial, (2) impact of helium flush, (3) sampling speed. This study showed that atmospheric CO2 does not impact the measurement, that helium flush can lead to isotopic fractionation and finally, that a fractionation occurs only 5h after bottle opening. The method, without any other preparation, consists in sampling 0.2 mL of cold (4 °C) cider in a vial that is passed in an ultrasonic bath for 10 min at room temperature to enhance cider de-carbonation. The headspace CO2 is then analysed using the link Multiflow®-isotope ratio mass spectrometer. Each year, a data bank is developed by fermenting authentic apples juices in order to control cider authenticity. Over a four year span (2008-2011), the CO2 produced during the fermentation step was studied. This set of 61 authentic ciders, from various French production areas, was used to determine a δ(13)C value range of -22.59±0.92‰ for authentic ciders CO2 bubbles. 75 commercial ciders were analysed with this method. Most of the samples analysed present a gas δ(13)C value in the expected range. Nevertheless, some ciders have δ(13)C values outside the 3σ limit, revealing carbonation by technical CO2. This practice is not allowed for organic, "Controlled Appellation of Origin" ciders and ciders specifying natural carbonation on the label. PMID:23870934

  17. Reevaluated martian atmospheric mixing ratios from the mass spectrometer on the Curiosity rover

    NASA Astrophysics Data System (ADS)

    Franz, Heather B.; Trainer, Melissa G.; Wong, Michael H.; Mahaffy, Paul R.; Atreya, Sushil K.; Manning, Heidi L. K.; Stern, Jennifer C.

    2015-05-01

    The Sample Analysis at Mars (SAM) instrument suite of the Mars Science Laboratory (MSL) Curiosity rover is a miniature geochemical laboratory designed to analyze martian atmospheric gases as well as volatiles released by pyrolysis of solid surface materials (Mahaffy et al., 2012). SAM began sampling the martian atmosphere to measure its chemical and isotopic composition shortly after Curiosity landed in Mars' Gale Crater in August 2012 (Mahaffy et al., 2013). Analytical methods and constants required for atmospheric measurements with SAM's quadrupole mass spectrometer (QMS) were provided in a previous contribution (Franz et al., 2014). Review of results obtained through application of these constants to repeated analyses over a full martian year and supporting studies with laboratory instruments offer new insights into QMS performance that allow refinement of the calibration constants and critical reassessment of their estimated uncertainties. This report describes the findings of these studies, provides updated calibration constants for atmospheric analyses with the SAM QMS, and compares volume mixing ratios for the martian atmosphere retrieved with the revised constants to those initially reported (Mahaffy et al., 2013). Sufficient confidence is enabled by the extended data set to support calculation of precise abundances for CO rather than an upper limit. Reanalysis of data acquired on mission sols 45 and 77 (at solar longitudes of 175° and 193°, respectively) with the revised constants leads to the following average volume mixing ratios: CO2 0.957(±0.016), N2 0.0203(±0.0003), Ar 0.0207(±0.0002), O2 1.73(±0.06)×10-3, CO 7.49(±0.026)×10-4.

  18. High-precision comparison of the antiproton-to-proton charge-to-mass ratio.

    PubMed

    Ulmer, S; Smorra, C; Mooser, A; Franke, K; Nagahama, H; Schneider, G; Higuchi, T; Van Gorp, S; Blaum, K; Matsuda, Y; Quint, W; Walz, J; Yamazaki, Y

    2015-08-13

    Invariance under the charge, parity, time-reversal (CPT) transformation is one of the fundamental symmetries of the standard model of particle physics. This CPT invariance implies that the fundamental properties of antiparticles and their matter-conjugates are identical, apart from signs. There is a deep link between CPT invariance and Lorentz symmetry--that is, the laws of nature seem to be invariant under the symmetry transformation of spacetime--although it is model dependent. A number of high-precision CPT and Lorentz invariance tests--using a co-magnetometer, a torsion pendulum and a maser, among others--have been performed, but only a few direct high-precision CPT tests that compare the fundamental properties of matter and antimatter are available. Here we report high-precision cyclotron frequency comparisons of a single antiproton and a negatively charged hydrogen ion (H(-)) carried out in a Penning trap system. From 13,000 frequency measurements we compare the charge-to-mass ratio for the antiproton (q/m)p- to that for the proton (q/m)p and obtain (q/m)p-/(q/m)p − 1 =1(69) × 10(-12). The measurements were performed at cyclotron frequencies of 29.6 megahertz, so our result shows that the CPT theorem holds at the atto-electronvolt scale. Our precision of 69 parts per trillion exceeds the energy resolution of previous antiproton-to-proton mass comparisons as well as the respective figure of merit of the standard model extension by a factor of four. In addition, we give a limit on sidereal variations in the measured ratio of <720 parts per trillion. By following the arguments of ref. 11, our result can be interpreted as a stringent test of the weak equivalence principle of general relativity using baryonic antimatter, and it sets a new limit on the gravitational anomaly parameter of |α − 1| < 8.7 × 10(-7). PMID:26268189

  19. Detection of dehydroepiandrosterone misuse by means of gas chromatography- combustion-isotope ratio mass spectrometry.

    PubMed

    Mareck, Ute; Geyer, Hans; Flenker, Ulrich; Piper, Thomas; Thevis, Mario; Schänzer, Wilhelm

    2007-01-01

    According to World Anti-Doping Agency (WADA) rules (WADA Technical Document-TD2004EAAS) urine samples containing dehydroepiandrosterone (DHEA) concentrations greater than 100 ng ML(-1) shall be submitted to isotope ratio mass spectrometry (IRMS) analysis. The threshold concentration is based on the equivalent to the glucuronide, and the DHEA concentrations have to be adjusted for a specific gravity value of 1.020. In 2006, 11,012 doping control urine samples from national and international federations were analyzed in the Cologne doping control laboratory, 100 (0.9%) of them yielding concentrations of DHEA greater than 100 ng mL(-1). Sixty-eight percent of the specimens showed specific gravity values higher than 1.020, 52% originated from soccer players, 95% were taken in competition, 85% were male urines, 99% of the IRMS results did not indicate an application of testosterone or related prohormones. Only one urine sample was reported as an adverse analytical finding having 319 ng mL(-1) DHEA (screening result), more than 10,000 ng mL(-1) androsterone and depleted carbon isotope ratio values for the testosterone metabolites androsterone and etiocholanolone. Statistical evaluation showed significantly different DHEA concentrations between specimens taken in- and out-of- competition, whereas females showed smaller DHEA values than males for both types of control. Also a strong influence of the DHEA excretion on different sport disciplines was detectable. The highest DHEA values were detected for game sports (soccer, basketball, handball, ice hockey), followed by boxing and wrestling. In 2007, 6622 doping control urine samples were analyzed for 3alpha,5-cyclo-5alpha-androstan-6beta-ol-17-one (3alpha,5-cyclo), a DHEA metabolite which was described as a useful gas chromatography-mass spectrometry (GC-MS) screening marker for DHEA abuse. Nineteen urine specimens showed concentrations higher than the suggested threshold of 140 ng mL(-1), six urine samples yielded

  20. Marked long-term decline in ambient CO mixing ratio in SE England, 1997–2014: evidence of policy success in improving air quality

    PubMed Central

    Lowry, D.; Lanoisellé, M. E.; Fisher, R. E.; Martin, M.; Fowler, C. M. R.; France, J. L.; Hernández-Paniagua, I. Y.; Novelli, P. C.; Sriskantharajah, S.; O’Brien, P.; Rata, N. D.; Holmes, C. W.; Fleming, Z. L.; Clemitshaw, K. C.; Zazzeri, G.; Pommier, M.; McLinden, C. A.; Nisbet, E. G.

    2016-01-01

    Atmospheric CO at Egham in SE England has shown a marked and progressive decline since 1997, following adoption of strict controls on emissions. The Egham site is uniquely positioned to allow both assessment and comparison of ‘clean Atlantic background’ air and CO-enriched air downwind from the London conurbation. The decline is strongest (approximately 50 ppb per year) in the 1997–2003 period but continues post 2003. A ‘local CO increment’ can be identified as the residual after subtraction of contemporary background Atlantic CO mixing ratios from measured values at Egham. This increment, which is primarily from regional sources (during anticyclonic or northerly winds) or from the European continent (with easterly air mass origins), has significant seasonality, but overall has declined steadily since 1997. On many days of the year CO measured at Egham is now not far above Atlantic background levels measured at Mace Head (Ireland). The results are consistent with MOPITT satellite observations and ‘bottom-up’ inventory results. Comparison with urban and regional background CO mixing ratios in Hong Kong demonstrates the importance of regional, as opposed to local reduction of CO emission. The Egham record implies that controls on emissions subsequent to legislation have been extremely successful in the UK. PMID:27210416

  1. Marked long-term decline in ambient CO mixing ratio in SE England, 1997–2014: evidence of policy success in improving air quality

    NASA Astrophysics Data System (ADS)

    Lowry, D.; Lanoisellé, M. E.; Fisher, R. E.; Martin, M.; Fowler, C. M. R.; France, J. L.; Hernández-Paniagua, I. Y.; Novelli, P. C.; Sriskantharajah, S.; O’Brien, P.; Rata, N. D.; Holmes, C. W.; Fleming, Z. L.; Clemitshaw, K. C.; Zazzeri, G.; Pommier, M.; McLinden, C. A.; Nisbet, E. G.

    2016-05-01

    Atmospheric CO at Egham in SE England has shown a marked and progressive decline since 1997, following adoption of strict controls on emissions. The Egham site is uniquely positioned to allow both assessment and comparison of ‘clean Atlantic background’ air and CO-enriched air downwind from the London conurbation. The decline is strongest (approximately 50 ppb per year) in the 1997–2003 period but continues post 2003. A ‘local CO increment’ can be identified as the residual after subtraction of contemporary background Atlantic CO mixing ratios from measured values at Egham. This increment, which is primarily from regional sources (during anticyclonic or northerly winds) or from the European continent (with easterly air mass origins), has significant seasonality, but overall has declined steadily since 1997. On many days of the year CO measured at Egham is now not far above Atlantic background levels measured at Mace Head (Ireland). The results are consistent with MOPITT satellite observations and ‘bottom-up’ inventory results. Comparison with urban and regional background CO mixing ratios in Hong Kong demonstrates the importance of regional, as opposed to local reduction of CO emission. The Egham record implies that controls on emissions subsequent to legislation have been extremely successful in the UK.

  2. Marked long-term decline in ambient CO mixing ratio in SE England, 1997-2014: evidence of policy success in improving air quality.

    PubMed

    Lowry, D; Lanoisellé, M E; Fisher, R E; Martin, M; Fowler, C M R; France, J L; Hernández-Paniagua, I Y; Novelli, P C; Sriskantharajah, S; O'Brien, P; Rata, N D; Holmes, C W; Fleming, Z L; Clemitshaw, K C; Zazzeri, G; Pommier, M; McLinden, C A; Nisbet, E G

    2016-01-01

    Atmospheric CO at Egham in SE England has shown a marked and progressive decline since 1997, following adoption of strict controls on emissions. The Egham site is uniquely positioned to allow both assessment and comparison of 'clean Atlantic background' air and CO-enriched air downwind from the London conurbation. The decline is strongest (approximately 50 ppb per year) in the 1997-2003 period but continues post 2003. A 'local CO increment' can be identified as the residual after subtraction of contemporary background Atlantic CO mixing ratios from measured values at Egham. This increment, which is primarily from regional sources (during anticyclonic or northerly winds) or from the European continent (with easterly air mass origins), has significant seasonality, but overall has declined steadily since 1997. On many days of the year CO measured at Egham is now not far above Atlantic background levels measured at Mace Head (Ireland). The results are consistent with MOPITT satellite observations and 'bottom-up' inventory results. Comparison with urban and regional background CO mixing ratios in Hong Kong demonstrates the importance of regional, as opposed to local reduction of CO emission. The Egham record implies that controls on emissions subsequent to legislation have been extremely successful in the UK. PMID:27210416

  3. Charge and discharge of polar cold air mass in northern hemispheric winter

    NASA Astrophysics Data System (ADS)

    Kanno, Yuki; Abdillah, Muhammad Rais; Iwasaki, Toshiki

    2015-09-01

    This study shows the variability of polar cold air mass amount below potential temperature of 280 K, and north of 45°N can be understood with a concept of charge and discharge, where anomalously large daily discharge indicates an intermittent occurrence of cold air outbreak. The polar cold air mass amount north of 45°N gradually charges up due to diabatic cooling but dramatically discharges due to cold air outbreak with a pulse width of about 5 days. Cold air outbreaks tend to bring colder winter in East Asia and the east coast of North America, while warmer winter prevails on the northern side of these regions. The cold air mass amount south of 45°N increases just after a cold air outbreak but returns to the normal level soon because of its life time of about 3 days. Therefore, monthly mean of total cold air mass amount in the Northern Hemisphere is negatively correlated with the monthly mean discharge.

  4. FUNDAMENTAL MASS TRANSFER MODEL FOR INDOOR AIR EMISSION FROM SURFACE COATINGS

    EPA Science Inventory

    The paper, discusses the work of researchers at the U.S. EPA's Air and Energy Engineering Research Laboratory (Indoor Air Branch) who are evaluating mass transfer models based on fundamental principles to determine their effectiveness in predicting emissions from indoor architect...

  5. DNAPL REMOVAL MECHANISMS AND MASS TRANSFER CHARACTERISTICS DURING COSOLVENT-AIR FLOODING

    EPA Science Inventory

    The concurrent injection of cosolvent and air, a cosolvent-air (CA) flood was recently suggested for a dense nonaqueous phase liquid (DNAPL) remediation technology. The objectives of this study were to elucidate the DNAPL removal mechanisms of the CA flood and to quantify mass t...

  6. Experimental Determination of the Mass of Air Molecules from the Law of Atmospheres.

    ERIC Educational Resources Information Center

    Hayn, Carl H.; Galvin, Vincent, Jr.

    1979-01-01

    A gas pressure gauge has been constructed for use in a student experiment involving the law of atmospheres. From pressure data obtained at selected elevations the average mass of air molecules is determined and compared to that calculated from the molecular weights and percentages of constituents to the air. (Author/BB)

  7. Effect of OH depletion on measurements of the mass-to-flux ratio in molecular cloud cores

    NASA Astrophysics Data System (ADS)

    Tassis, K.; Willacy, K.; Yorke, Harold W.; Turner, Neal J.

    2014-11-01

    The ratio of mass and magnetic flux determines the relative importance of magnetic and gravitational forces in the evolution of molecular clouds and their cores. Its measurement is thus central in discriminating between different theories of core formation and evolution. Here, we discuss the effect of chemical depletion on measurements of the mass-to-flux ratio using the same molecule (OH) both for Zeeman measurements of the magnetic field and the determination of the mass of the region. The uncertainties entering through the OH abundance in determining separately the magnetic field and the mass of a region have been recognized in the literature. It has been proposed however that, when comparing two regions of the same cloud, the abundance will in both cases be the same. We show that this assumption is invalid. We demonstrate that when comparing regions with different densities, the effect of OH depletion, in measuring changes of the mass-to-flux ratio between different parts of the same cloud can even reverse the direction of the underlying trends (for example, the mass-to-flux ratio may appear to decrease as we move to higher density regions). The systematic errors enter primarily through the inadequate estimation of the mass of the region.

  8. Short-term Fallout Radionuclide Ratios and Mass Balance Identify New Suspended Sediments of Channel Origin

    NASA Astrophysics Data System (ADS)

    Karwan, D. L.; Pizzuto, J. E.; Aalto, R. E.; Marquard, J.; Aufdenkampe, A. K.; Benthem, A.; Skalak, K.; Levia, D. F., Jr.; Siegert, C. M.

    2015-12-01

    Fallout radionuclide ratios, such as the ratio of Beryllium-7 to Lead-210 (7Be/210Pb), are used to determine the age of suspended sediment or fraction of "new" sediment in suspension. In the application of these models new suspended sediment is often assumed to originate from recent landscape surface erosion that is delivered to the stream network. Fallout radionuclide deposition can vary across watersheds and on an event basis in a single watershed due to factors such as storm type, atmospheric height, and storm origin. In the White Clay Creek watershed within the mid-Atlantic USA, single-event deposition of 7Be varies from 15 - 177 Bq m-2 and 210Pb varies from 0 - 10 Bq m-2. 7Be/210Pb ratios vary from 7.9 to 20 in event precipitation and from 0.8 to 12.8 on suspended sediment. "New" sediment varies from 4 - 71% over the course of these events. A computation of the 7Be mass balance during events shows that the majority of 7Be is retained within the catchment. During summer thunderstorms, less than 1% of 7Be deposited on the watershed exits in the stream channel during that event. Therefore, the entirety of the 7Be exiting the watershed on suspended sediment is less than the total activity deposited on the channel in direct precipitation. We attribute this to the new tagging of subaerial fluvial deposits with event precipitation; hence "new" suspended sediment originates from within the channel rather than from surface erosion. During extreme events, such as Hurricane Irene, less of the suspended sediment has been newly tagged by precipitation (4 - 28%) and a larger proportion (3-4%) of the 7Be deposited on the watershed exits during the event. Ongoing work in the Difficult Run watershed in northern Virginia will test the regional applicability of these findings. Water quality efforts to determine the source of sediment using fallout radionuclides must consider the stream channel as well as landscape sources of "new" sediments, particularly during summer

  9. The local stellar luminosity function and mass-to-light ratio in the near-infrared

    NASA Astrophysics Data System (ADS)

    Just, A.; Fuchs, B.; Jahreiß, H.; Flynn, C.; Dettbarn, C.; Rybizki, J.

    2015-07-01

    A new sample of stars, representative of the solar neighbourhood luminosity function (LF), is constructed from the Hipparcos catalogue and the Fifth Catalogue of Nearby Stars. We have cross-matched to sources in the Two Micron All Sky Survey catalogue so that for all stars individually determined near-infrared (NIR) photometry is available on a homogeneous system (typically Ks). The spatial completeness of the sample has been carefully determined by statistical methods, and the NIR LF of the stars has been derived by direct star counts. We find a local volume luminosity of 0.121 ± 0.004 LK⊙ pc-3, corresponding to a volumetric mass-to-light ratio (M/L) of M/L_K = 0.31 ± 0.02 {M}_{⊙}/L_{K⊙}, where giants contribute 80 per cent to the light but less than 2 per cent to the stellar mass. We derive the surface brightness of the solar cylinder with the help of a vertical disc model. We find a surface brightness of 99 LK⊙ pc-2 with an uncertainty of approximately 10 per cent. This corresponds to an M/L for the solar cylinder of M/L_K = 0.34 {M}_{⊙}/L_{K⊙}. The M/L for the solar cylinder is only 10 per cent larger than the local value despite the fact that the local population has a much larger contribution of young stars. It turns out that the effective scaleheights of the lower main sequence carrying most of the mass is similar to that of the giants, which are dominating the NIR light. The corresponding colour for the solar cylinder is V - K = 2.89 mag compared to the local value of V - K = 2.46 mag. An extrapolation of the local surface brightness to the whole Milky Way yields a total luminosity of MK = -24.2 mag. The Milky Way falls in the range of K band Tully-Fisher relations from the literature.

  10. Gas-to-dust mass ratios in local galaxies over a 2 dex metallicity range

    NASA Astrophysics Data System (ADS)

    Rémy-Ruyer, A.; Madden, S. C.; Galliano, F.; Galametz, M.; Takeuchi, T. T.; Asano, R. S.; Zhukovska, S.; Lebouteiller, V.; Cormier, D.; Jones, A.; Bocchio, M.; Baes, M.; Bendo, G. J.; Boquien, M.; Boselli, A.; DeLooze, I.; Doublier-Pritchard, V.; Hughes, T.; Karczewski, O. Ł.; Spinoglio, L.

    2014-03-01

    Aims: The goal of this paper is to analyse the behaviour of the gas-to-dust mass ratio (G/D) of local Universe galaxies over a wide metallicity range. We especially focus on the low-metallicity part of the G/D vs metallicity relation and investigate several explanations for the observed relation and scatter. Methods: We assembled a total of 126 galaxies, covering a 2 dex metallicity range and with 30% of the sample with 12 + log(O/H)≤ 8.0. We homogeneously determined the dust masses with a semi-empirical dust model including submm constraints. The atomic and molecular gas masses have been compiled from the literature. We used two XCO scenarios to estimate the molecular gas mass: the Galactic conversion factor, XCO,MW, and a XCO that depends on the metallicity XCO,Z (∝Z-2). We modelled the observed trend of the G/D with metallicity using two simple power laws (slope of -1 and free) and a broken power law. Correlations with morphological type, stellar masses, star formation rates, and specific star formation rates are also discussed. We then compared the observed evolution of the G/D with predictions from several chemical evolution models and explored different physical explanations for the observed scatter in the G/D values. Results: We find that out of the five tested galactic parameters, metallicity is the main physical property of the galaxy driving the observed G/D. The G/D versus metallicity relation cannot be represented by a single power law with a slope of -1 over the whole metallicity range. The observed trend is steeper for metallicities lower than ~8.0. A large scatter is observed in the G/D values for a given metallicity: in metallicity bins of ~0.1 dex, the dispersion around the mean value is ~0.37 dex. On average, the broken power law reproduces the observed G/D best compared to the two power laws (slope of -1 or free) and provides estimates of the G/D that are accurate to a factor of 1.6. The good agreement of observed values of the G/D and its

  11. Modeling of the Calcium/Phosphorus Mass ratio for Breast Imaging

    NASA Astrophysics Data System (ADS)

    Martini, N.; Koukou, V.; Michail, C.; Sotiropoulou, P.; Kalyvas, N.; Kandarakis, I.; Nikiforidis, G.; Fountos, G.

    2015-09-01

    Breast microcalcifications are mainly composed of calcite (CaCO3), calcium oxalate (CaC2O4) and apatite (a calcium-phosphate mineral form). Any pathologic alteration (carcinogenesis) of the breast may produce apatite. In the present simulation study, an analytical model was implemented in order to distinguish malignant and non-malignant lesions. The Calcium/Phosphorus (Ca/P) mass ratio and the standard deviation (SD) of the calcifications were calculated. The size of the calcifications ranged from 100 to 1000 μm, in 50 μm increments. The simulation was performed for hydroxyapatite, calcite and calcium oxalate calcifications. The optimum pair of energies for all calcifications was 22keV and 50keV. Hydroxyapatite and calcite calcifications were sufficiently characterized through their distinct confidence interval (99.7%, 3SD) values for calcifications sizes above 500 μm, while the corresponding sizes for hydroxyapatite and calcium oxalate characterization were found above 250 μm. Initial computer simulation results indicate that the proposed method can be used in breast cancer diagnosis, reducing the need for invasive methods, such as biopsies.

  12. The application of isotope ratio mass spectrometry for discrimination and comparison of adhesive tapes.

    PubMed

    Horacek, Micha; Min, Ji-Sook; Heo, Sangcheol; Park, Jongseo; Papesch, Wolfgang

    2008-06-01

    Forensic scientists are frequently requested to differentiate between, or compare, adhesive tapes from a suspect or a crime scene. The most common polymers used to back packaging tape are polypropylene and polyvinyl chloride. Much of the oriented polypropylene (OPP) needed to produce packaging tapes, regardless of the tape brand, is supplied by just a few polymer manufacturers. Consequently, the composition of the backing material varies little. Therefore, the discriminating power of classical methods (physical fit, tape dimensions, colour, morphology, FTIR, PyGC/MS, etc.) is limited. Analysis of stable isotopes using isotope ratio mass spectrometry (IRMS) has been applied in the broad area of forensics and it has been reported that isotope analysis is a valuable tool for the identification of adhesive tapes. We have tested the usefulness of this method by distinguishing different South Korean adhesive tapes produced by just a few manufacturers in the small South Korean market. Korean adhesive tapes were collected and analysed for their isotope signatures. The glue of the tapes was separated from the backing material and these sub-samples were analysed for their H- and C-isotope composition. The result shows the possibility for discriminating most tape samples, even from the same brand. Variations within single rolls have also been investigated, where no variations in H- and C-isotope composition significantly exceeding the standard deviation were found. PMID:18438979

  13. Persistent junk solutions in time-domain modeling of extreme mass ratio binaries

    NASA Astrophysics Data System (ADS)

    Field, Scott E.; Hesthaven, Jan S.; Lau, Stephen R.

    2010-06-01

    In the context of metric perturbation theory for nonspinning black holes, extreme mass ratio binary systems are described by distributionally forced master wave equations. Numerical solution of a master wave equation as an initial boundary value problem requires initial data. However, because the correct initial data for generic-orbit systems is unknown, specification of trivial initial data is a common choice, despite being inconsistent and resulting in a solution which is initially discontinuous in time. As is well known, this choice leads to a burst of junk radiation which eventually propagates off the computational domain. We observe another potential consequence of trivial initial data: development of a persistent spurious solution, here referred to as the Jost junk solution, which contaminates the physical solution for long times. This work studies the influence of both types of junk on metric perturbations, waveforms, and self-force measurements, and it demonstrates that smooth modified source terms mollify the Jost solution and reduce junk radiation. Our concluding section discusses the applicability of these observations to other numerical schemes and techniques used to solve distributionally forced master wave equations.

  14. Calibration and Data Processing in Gas Chromatography Combustion Isotope Ratio Mass Spectrometry

    PubMed Central

    Zhang, Ying; Tobias, Herbert J.; Sacks, Gavin L.; Brenna, J. Thomas

    2013-01-01

    Compound-specific isotope analysis (CSIA) by gas chromatography combustion isotope ratio mass spectrometry (GCC-IRMS) is a powerful technique for the sourcing of substances, such as determination of the geographic or chemical origin of drugs and food adulteration, and it is especially invaluable as a confirmatory tool for detection of the use of synthetic steroids in competitive sport. We review here principles and practices for data processing and calibration of GCC-IRMS data with consideration to anti-doping analyses, with a focus on carbon isotopic analysis (13C/12C). After a brief review of peak definition, the isotopologue signal reduction methods of summation, curve-fitting, and linear regression are described and reviewed. Principles for isotopic calibration are considered in the context of the Δ13C = δ13CM – δ13CE difference measurements required for establishing adverse analytical findings for metabolites relative to endogenous reference compounds. Considerations for the anti-doping analyst are reviewed. PMID:22362612

  15. Caution on the use of liquid nitrogen traps in stable hydrogen isotope-ratio mass spectrometry.

    PubMed

    Coplen, Tyler B; Qi, Haiping

    2010-09-15

    An anomalous stable hydrogen isotopic fractionation of 4 ‰ in gaseous hydrogen has been correlated with the process of adding liquid nitrogen (LN(2)) to top off the dewar of a stainless-steel water trap on a gaseous hydrogen-water platinum equilibration system. Although the cause of this isotopic fractionation is unknown, its effect can be mitigated by (1) increasing the capacity of any dewars so that they do not need to be filled during a daily analytic run, (2) interspersing isotopic reference waters among unknowns, and (3) applying a linear drift correction and linear normalization to isotopic results with a program such as Laboratory Information Management System (LIMS) for Light Stable Isotopes. With adoption of the above guidelines, measurement uncertainty can be substantially improved. For example, the long-term (months to years) δ(2)H reproducibility (1σ standard deviation) of nine local isotopic reference waters analyzed daily improved substantially from about 1 ‰ to 0.58 ‰. This isotopically fractionating mechanism might affect other isotope-ratio mass spectrometers in which LN(2) is used as a moisture trap for gaseous hydrogen. PMID:20718408

  16. Caution on the use of liquid nitrogen traps in stable hydrogen isotope-ratio mass spectrometry

    USGS Publications Warehouse

    Coplen, T.B.; Qi, H.

    2010-01-01

    An anomalous stable hydrogen isotopic fractionation of 4 ??? in gaseous hydrogen has been correlated with the process of adding liquid nitrogen (LN2) to top off the dewar of a stainless-steel water trap on a gaseous hydrogen-water platinum equilibration system. Although the cause of this isotopic fractionation is unknown, its effect can be mitigated by (1) increasing the capacity of any dewars so that they do not need to be filled during a daily analytic run, (2) interspersing isotopic reference waters among unknowns, and (3) applying a linear drift correction and linear normalization to isotopic results with a program such as Laboratory Information Management System (LIMS) for Light Stable Isotopes. With adoption of the above guidelines, measurement uncertainty can be substantially improved. For example, the long-term (months to years) ??2H reproducibility (1?? standard deviation) of nine local isotopic reference waters analyzed daily improved substantially from about 1 ??? to 0.58 ???. This isotopically fractionating mechanism might affect other isotope-ratio mass spectrometers in which LN2 is used as a moisture trap for gaseous hydrogen. ?? This article not subject to U.S. Copyright. Published 2010 by the American Chemical Society.

  17. Caution on the use of liquid nitrogen traps in stable hydrogen isotope-ratio mass spectrometry

    USGS Publications Warehouse

    Coplen, Tyler B.; Qi, Haiping

    2010-01-01

    An anomalous stable hydrogen isotopic fractionation of 4 ‰ in gaseous hydrogen has been correlated with the process of adding liquid nitrogen (LN2) to top off the dewar of a stainless-steel water trap on a gaseous hydrogen-water platinum equilibration system. Although the cause of this isotopic fractionation is unknown, its effect can be mitigated by (1) increasing the capacity of any dewars so that they do not need to be filled during a daily analytic run, (2) interspersing isotopic reference waters among unknowns, and (3) applying a linear drift correction and linear normalization to isotopic results with a program such as Laboratory Information Management System (LIMS) for Light Stable Isotopes. With adoption of the above guidelines, measurement uncertainty can be substantially improved. For example, the long-term (months to years) δ2H reproducibility (1& sigma; standard deviation) of nine local isotopic reference waters analyzed daily improved substantially from about 1‰ to 0.58 ‰. This isotopically fractionating mechanism might affect other isotope-ratio mass spectrometers in which LN2 is used as a moisture trap for gaseous hydrogen

  18. Kinetic electron and ion instability of the lunar wake simulated at physical mass ratio

    NASA Astrophysics Data System (ADS)

    Haakonsen, Christian Bernt; Hutchinson, Ian H.; Zhou, Chuteng

    2015-03-01

    The solar wind wake behind the moon is studied with 1D electrostatic particle-in-cell (PIC) simulations using a physical ion to electron mass ratio (unlike prior investigations); the simulations also apply more generally to supersonic flow of dense magnetized plasma past non-magnetic objects. A hybrid electrostatic Boltzmann electron treatment is first used to investigate the ion stability in the absence of kinetic electron effects, showing that the ions are two-stream unstable for downstream wake distances (in lunar radii) greater than about three times the solar wind Mach number. Simulations with PIC electrons are then used to show that kinetic electron effects can lead to disruption of the ion beams at least three times closer to the moon than in the hybrid simulations. This disruption occurs as the result of a novel wake phenomenon: the non-linear growth of electron holes spawned from a narrow dimple in the electron velocity distribution. Most of the holes arising from the dimple are small and quickly leave the wake, approximately following the unperturbed electron phase-space trajectories, but some holes originating near the center of the wake remain and grow large enough to trigger disruption of the ion beams. Non-linear kinetic-electron effects are therefore essential to a comprehensive understanding of the 1D electrostatic stability of such wakes, and possible observational signatures in ARTEMIS data from the lunar wake are discussed.

  19. Kinetic electron and ion instability of the lunar wake simulated at physical mass ratio

    SciTech Connect

    Haakonsen, Christian Bernt Hutchinson, Ian H. Zhou, Chuteng

    2015-03-15

    The solar wind wake behind the moon is studied with 1D electrostatic particle-in-cell (PIC) simulations using a physical ion to electron mass ratio (unlike prior investigations); the simulations also apply more generally to supersonic flow of dense magnetized plasma past non-magnetic objects. A hybrid electrostatic Boltzmann electron treatment is first used to investigate the ion stability in the absence of kinetic electron effects, showing that the ions are two-stream unstable for downstream wake distances (in lunar radii) greater than about three times the solar wind Mach number. Simulations with PIC electrons are then used to show that kinetic electron effects can lead to disruption of the ion beams at least three times closer to the moon than in the hybrid simulations. This disruption occurs as the result of a novel wake phenomenon: the non-linear growth of electron holes spawned from a narrow dimple in the electron velocity distribution. Most of the holes arising from the dimple are small and quickly leave the wake, approximately following the unperturbed electron phase-space trajectories, but some holes originating near the center of the wake remain and grow large enough to trigger disruption of the ion beams. Non-linear kinetic-electron effects are therefore essential to a comprehensive understanding of the 1D electrostatic stability of such wakes, and possible observational signatures in ARTEMIS data from the lunar wake are discussed.

  20. Calibration and data processing in gas chromatography combustion isotope ratio mass spectrometry.

    PubMed

    Zhang, Ying; Tobias, Herbert J; Sacks, Gavin L; Brenna, J Thomas

    2012-12-01

    Compound-specific isotope analysis (CSIA) by gas chromatography combustion isotope ratio mass spectrometry (GCC-IRMS) is a powerful technique for the sourcing of substances, such as determination of the geographic or chemical origin of drugs and food adulteration, and it is especially invaluable as a confirmatory tool for detection of the use of synthetic steroids in competitive sport. We review here principles and practices for data processing and calibration of GCC-IRMS data with consideration to anti-doping analyses, with a focus on carbon isotopic analysis ((13)C/(12)C). After a brief review of peak definition, the isotopologue signal reduction methods of summation, curve-fitting, and linear regression are described and reviewed. Principles for isotopic calibration are considered in the context of the Δ(13)C = δ(13)C(M) - δ(13)C(E) difference measurements required for establishing adverse analytical findings for metabolites (M) relative to endogenous (E) reference compounds. Considerations for the anti-doping analyst are reviewed. PMID:22362612

  1. THE DEMOGRAPHICS OF BROAD-LINE QUASARS IN THE MASS-LUMINOSITY PLANE. II. BLACK HOLE MASS AND EDDINGTON RATIO FUNCTIONS

    SciTech Connect

    Kelly, Brandon C.; Shen, Yue

    2013-02-10

    We employ a flexible Bayesian technique to estimate the black hole (BH) mass and Eddington ratio functions for Type 1 (i.e., broad line) quasars from a uniformly selected data set of {approx}58, 000 quasars from the Sloan Digital Sky Survey (SDSS) DR7. We find that the SDSS becomes significantly incomplete at M {sub BH} {approx}< 3 Multiplication-Sign 10{sup 8} M {sub Sun} or L/L {sub Edd} {approx}< 0.07, and that the number densities of Type 1 quasars continue to increase down to these limits. Both the mass and Eddington ratio functions show evidence of downsizing, with the most massive and highest Eddington ratio BHs experiencing Type 1 quasar phases first, although the Eddington ratio number densities are flat at z < 2. We estimate the maximum Eddington ratio of Type 1 quasars in the observable universe to be L/L {sub Edd} {approx} 3. Consistent with our results in Shen and Kelly, we do not find statistical evidence for a so-called sub-Eddington boundary in the mass-luminosity plane of broad-line quasars, and demonstrate that such an apparent boundary in the observed distribution can be caused by selection effect and errors in virial BH mass estimates. Based on the typical Eddington ratio in a given mass bin, we estimate growth times for the BHs in Type 1 quasars and find that they are comparable to or longer than the age of the universe, implying an earlier phase of accelerated (i.e., with higher Eddington ratios) and possibly obscured growth. The large masses probed by our sample imply that most of our BHs reside in what are locally early-type galaxies, and we interpret our results within the context of models of self-regulated BH growth.

  2. Body mass index and waist-to-height ratio among schoolchildren with visual impairment

    PubMed Central

    Magdalena, Wrzesińska; Urzędowicz, Beata; Motylewski, Sławomir; Zeman, Krzysztof; Pawlicki, Lucjan

    2016-01-01

    Abstract Children and adolescents with visual impairments may be predisposed to excessive body mass due to restrictions in everyday functioning and the ability to take part in physical activity. This study aimed to estimate the prevalence of obesity, overweight, and abdominal obesity (AO) among blind and partially sighted schoolchildren and to determine whether sociodemographic factors and participation in physical education classes (PEC) are associated with excessive body weight or AO in this group. A cross-sectional sample of 141 partially sighted or blind schoolchildren aged 7 to 18.9 years were included in this study. Anthropometric measurements were performed, and sociodemographic variables and ability to attend PEC were recorded. Overweight and obesity were noted among 21.3% and 14.9% of students, respectively. Although more males than females had excessive body weight (39.2% vs 32.3%), the difference was not significant (chi square test [ch2] = 3.197; probability value [P] = 0.362). There was a significant association between mean body mass index standard deviation score and age (results of ANOVA analysis [F] = 5.620; P = 0.0045). A waist-to-height ratio (WHtR) ≥0.50 was observed among 27.7% of pupils. The prevalence of AO in boys and girls was 32.9% and 21.0%, respectively; this difference was not significant (ch2 = 2.48; P = 0.12). There was a significant relationship between mean WHtR and age (7–9 years: 0.477 ± 0.050; 10–13 years: 0.484 ± 0.065; ≥14 years: 0.454 ± 0.061; results of Kruskal–Wallis test [H] = 8.729; P = 0.023, respectively). Multivariate logistic regression analysis showed that none of the sociodemographic variables examined (except “having siblings”) were significantly associated with the occurrence of overweight, obesity, and AO. Subjects with no siblings were 4 times more likely to have WHtR ≥ 0.5 (odds ratio [OR] = 4.22; 95% confidence interval [CI] = 1.33–17

  3. Gas chromatography flow rates for determining deuterium/hydrogen ratios of natural gas by gas chromatography/high-temperature conversion/isotope ratio mass spectrometry.

    PubMed

    Jia, Wanglu; Peng, Ping'an; Liu, Jinzhong

    2008-08-01

    The effects of the gas chromatography flow rate on the determination of the deuterium/hydrogen (D/H) ratios of natural gas utilising gas chromatography/high-temperature conversion/isotope ratio mass spectrometry (GC/TC/IRMS) have been evaluated. In general, the measured deltaD values of methane, ethane and propane decrease with increase in column flow rate. When the column flow rate is 1 mL/min or higher, which is commonly used for the determination of D/H ratios of natural gas, the organic H in gas compounds may not be completely converted into hydrogen gas. Based on the results of experiments conducted on a GC column with an i.d. of 0.32 mm, a GC flow rate of 0.6 mL/min is proposed for determining the D/H ratios of natural gas by GC/TC/IRMS. Although this value may be dependent on the instrument conditions used in this work, we believe that correct deltaD values of organic compounds with a few carbon atoms are obtained only when relatively low GC flow rates are used for D/H analysis by GC/TC/IRMS. Moreover, as the presence of trace water could significantly affect the determination of D/H ratios, a newly designed inlet liner was used to remove trace water contained in some gas samples. PMID:18636428

  4. Critical Mass Academic Planning. AIR Forum Paper 1978.

    ERIC Educational Resources Information Center

    Jones, Larry R.

    Methods of academic resource planning for research-oriented colleges and universities are explored. Focus is on resource allocation that is not strictly related to overall institutional enrollment level, but with the desirability of maintaining a minimum or "critical mass" levels of program breadth and quality. The purpose of critical mass…

  5. An update to the ambient ratio method for 1-h NO2 air quality standards dispersion modeling

    NASA Astrophysics Data System (ADS)

    Podrez, Mark

    2015-02-01

    Nitrogen oxide (NOX) gases are typically emitted by fuel combustion sources in the form of nitric oxide (NO), which then reacts with ozone and other oxidants in the atmosphere to convert a portion of the NO to nitrogen dioxide (NO2). EPA has promulgated a 1-h average National Ambient Air Quality Standard (NAAQS) for NO2, and major sources of NOX emissions must estimate their NO2 air quality impacts as part of EPA's air quality permitting programs. The AERMOD dispersion model has been developed by EPA for these air quality impact analyses, and AERMOD contains three different NO to NO2 conversion methods for estimating the ambient concentrations of NO2. This paper describes a refinement to one of the methods, the Ambient Ratio Method version 2 (ARM2). ARM2 is an empirical approach that uses a variable conversion factor, based on an analysis of ambient air measurements of NO and NO2, to estimate the portion of the AERMOD predicted air concentration of total NOX species that is in the form of NO2. The performance of ARM2 has been evaluated and found to compare well to actual ambient measurements and to other more complex EPA conversion methods. EPA has included ARM2 as a "beta-testing" option in AERMOD version 14134, and provided guidance on the use of ARM2 for regulatory modeling analyses in a September 2014 memorandum. This paper also discusses this recent EPA guidance.

  6. Experimental study of the water-to-air stopping power ratio of monoenergetic carbon ion beams for particle therapy

    NASA Astrophysics Data System (ADS)

    Sánchez-Parcerisa, D.; Gemmel, A.; Jäkel, O.; Parodi, K.; Rietzel, E.

    2012-06-01

    Reference dosimetry with ionization chambers requires a number of chamber-specific and beam-specific calibration factors. For carbon ion beams, IAEA report TRS-398 yields a total uncertainty of 3% in the determination of the absorbed dose to water, for which the biggest contribution arises from the water-to-air stopping power ratio (sw, air), with an uncertainty of 2%. The variation of (sw, air) along the treatment field has been studied in several Monte Carlo works presented over the last few years. Their results were, in all cases, strongly dependent on the choice of mean ionization potentials (I-values) for air and water. A smaller dependence of (sw, air) with penetration depth was observed. Since a consensus on Iw, air and Iair has not yet been reached, the validity of such studies for clinical use cannot be assessed independently. Our approach is based on a direct experimental measurement of water-equivalent thicknesses of different air gaps at different beam energies. A theoretical expression describing the variation of the stopping power ratio with kinetic energy, sw,air(E), was derived from the Bethe-Bloch formula and fit to the measured data, yielding a coherent pair of Iw and Iair values with Iair/Iw = 1.157 ± 0.023. Additionally, the data from five different beam energies were combined in an average value of sw,air = 1.132 ± 0.003 (statistical) ± 0.003 (variation over energy range), valid for monoenergetic carbon ion beams at the plateau area of the depth dose distribution. A detailed uncertainty analysis was performed on the data, in order to assess the limitations of the method, yielding an overall standard uncertainty below 1% in sw,air(E). Therefore, when properly combined with the appropriate models for the fragment spectra, our experimental work can contribute to narrow the uncertainty margins currently in use in absorbed dose to water determination for dosimetry of carbon ion beam radiotherapy.

  7. Optimum Installation of Sorptive Building Materials Using Contribution Ratio of Pollution Source for Improvement of Indoor Air Quality

    PubMed Central

    Park, Seonghyun; Seo, Janghoo

    2016-01-01

    Reinforcing the insulation and airtightness of buildings and the use of building materials containing new chemical substances have caused indoor air quality problems. Use of sorptive building materials along with removal of pollutants, constant ventilation, bake-out, etc. are gaining attention in Korea and Japan as methods for improving such indoor air quality problems. On the other hand, sorptive building materials are considered a passive method of reducing the concentration of pollutants, and their application should be reviewed in the early stages. Thus, in this research, activated carbon was prepared as a sorptive building material. Then, computational fluid dynamics (CFD) was conducted, and a method for optimal installation of sorptive building materials was derived according to the indoor environment using the contribution ratio of pollution source (CRP) index. The results show that a method for optimal installation of sorptive building materials can be derived by predicting the contribution ratio of pollutant sources according to the CRP index. PMID:27043605

  8. Optimum Installation of Sorptive Building Materials Using Contribution Ratio of Pollution Source for Improvement of Indoor Air Quality.

    PubMed

    Park, Seonghyun; Seo, Janghoo

    2016-04-01

    Reinforcing the insulation and airtightness of buildings and the use of building materials containing new chemical substances have caused indoor air quality problems. Use of sorptive building materials along with removal of pollutants, constant ventilation, bake-out, etc. are gaining attention in Korea and Japan as methods for improving such indoor air quality problems. On the other hand, sorptive building materials are considered a passive method of reducing the concentration of pollutants, and their application should be reviewed in the early stages. Thus, in this research, activated carbon was prepared as a sorptive building material. Then, computational fluid dynamics (CFD) was conducted, and a method for optimal installation of sorptive building materials was derived according to the indoor environment using the contribution ratio of pollution source (CRP) index. The results show that a method for optimal installation of sorptive building materials can be derived by predicting the contribution ratio of pollutant sources according to the CRP index. PMID:27043605

  9. LASER BIOLOGY AND MEDICINE: Laser analysis of the 13C/12C isotope ratio in CO2 in exhaled air

    NASA Astrophysics Data System (ADS)

    Stepanov, E. V.

    2002-11-01

    Tunable diode lasers (TDLs) are applied to the diagnostics of gastroenterological diseases using respiratory tests and preparations enriched with the stable 13C isotope. This method of the analysis of the 13C/12C isotope ratio in CO2 in exhaled air is based on the selective measurement of the resonance absorption at the vibrational — rotational structure of 12CO2 and 13CO2. The CO2 transmission spectra in the region of 4.35 μm were measured with a PbEuSe double-heterostructure TDL. The accuracy of carbon isotope ratio measurements in CO2 of exhaled air performed with the TDL was ~0.5%. The data of clinical tests of the developed laser-based analyser are presented.

  10. The Chemical Composition and Gas-to-Dust Mass Ratio of Nearby Interstellar Matter

    NASA Technical Reports Server (NTRS)

    Frisch, Priscilla C.; Slavin, Jonathan D.

    2003-01-01

    We use recent results on interstellar gas toward nearby stars and interstellar by-products within the solar system to select among the equilibrium radiative transfer models of the nearest interstellar material presented in Slavin & Frisch. For the assumption that O/H - 400 parts per million, models 2 and 8 are found to yield good fits to available data on interstellar material inside and outside of the heliosphere, with the exception of the Ne abundance in the pickup ion and anomalous cosmic-ray populations. For these models, the interstellar medium (ISM) at the entry point to the heliosphere has n(H(sup 0)) = 0.202-0.208/cu cm, n(He(sup 0) = 0.0137-0.0152/cu cm, and ionizations X(H) = 0.29-0.30, X(He) = 0.47-0.51. These best models suggest that the chemical composition of the nearby ISM is approx.60%-70% subsolar if S is undepleted. Both H(0) and H(+) need to be included when evaluating abundances of ions found in warm diffuse clouds. Models 2 and 8 yield an H filtration factor of approx.0.46. Gas-to-dust mass ratios for the ISM toward epsilon CMa are R(sub gd) = 178-183 for solar abundances of Holweger or R(sub gd) = 611-657 for an interstellar abundance standard 70% solar. Direct observations of dust grains in the solar system by Ulysses and Galileo yield R(sub gd) appr0x. 115 for models 2 and 8, supporting earlier results (Frisch and coworkers). If the local ISM abundances are subsolar, then gas and dust are decoupled over small spatial scales. The inferred variation in R(sub gd) over parsec length scales is consistent with the fact that the ISM near the Sun is part of a dynamically active cluster of cloudlets flowing away from the Sco-Cen association. Observations toward stars within approx.500 pc show that R(sub gd) correlates with the percentage of the dust mass that is carried by iron, suggesting that an Fe-rich grain core (by mass) remains after grain destruction. Evidently large dust grains (>10(exp -13) g) and small dust grains (<10(exp -13) g) are not

  11. SECULAR EVOLUTION AND A NON-EVOLVING BLACK-HOLE-TO-GALAXY MASS RATIO IN THE LAST 7 Gyr

    SciTech Connect

    Cisternas, Mauricio; Jahnke, Knud; Inskip, Katherine J.; Bongiorno, Angela; Merloni, Andrea; Impey, Chris D.; Koekemoer, Anton M.; Salvato, Mara; Trump, Jonathan R.

    2011-11-01

    We present new constraints on the ratio of black hole (BH) mass to total galaxy stellar mass at 0.3 < z < 0.9 for a sample of 32 type-1 active galactic nuclei (AGNs) from the XMM-COSMOS survey covering the range M{sub BH} {approx} 10{sup 7.2-8.7} M{sub sun}. Virial M{sub BH} estimates based on H{beta} are available from the COSMOS Magellan/IMACS survey. We use high-resolution Hubble Space Telescope (HST) imaging to decompose the light of each type-1 AGN and host galaxy, and employ a specially built mass-to-light ratio to estimate the stellar masses (M{sub *}). The M{sub BH}-M{sub *} ratio shows a zero offset with respect to the local relation for galactic bulge masses, and we also find no evolution in the mass ratio M{sub BH}/M{sub *}{proportional_to}(1 + z){sup 0.02{+-}0.34} up to z {approx} 0.9. Interestingly, at the high-M{sub BH} end there is a positive offset from the z = 0 relation, which can be fully explained by a mass function bias with a cosmic scatter of {sigma}{sub {mu}} = 0.3, reaffirming that the intrinsic distribution is consistent with zero evolution. From our results we conclude that since z {approx} 0.9 no substantial addition of stellar mass is required: the decline in star formation rates and merger activity at z < 1 support this scenario. Nevertheless, given that a significant fraction of these galaxies show a disk component, their bulges are indeed undermassive. This is a direct indication that for the last 7 Gyr the only essential mechanism required for these galaxies to obey the z = 0 relation is a redistribution of stellar mass to the bulge, likely driven by secular processes, i.e., internal instabilities and minor merging.

  12. Spectroscopy and photometry of the dwarf nova BZ Ursae Majoris and the CV linewidth/K, mass-ratio relation

    NASA Technical Reports Server (NTRS)

    Jurcevic, J. S.; Honeycutt, R. K.; Schlegel, E. M.; Webbink, R. F.

    1994-01-01

    Time-resolved spectroscopy of the dwarf nova BZ Ursae Majoris (BZ UMa) reveals periodic velocity variations in the hydrogen emission lines with P = 97.9 +/- 0.1 min and K = 73 +/- 6 km/s. CCD photometry over a 16-month interval shows three outbursts of about 4 mag with a mean separation of 181 days. The mean full width at half maximum (FWHM) for the hydrogen beta emission is large, prompting a recalibration of the FWHM/K vs. mass ratio relation, giving a mass ratio (M(sub RD)/M(sub WD)) of 0.20 for BZ UMa. The short period, long outburst interval, and small mass ratio support the suggestion of BZ UMa being in the SU Ursae Majoris subclass of dwarf novae.

  13. Isotope Ratio Mass Spectrometry and Shale Gas - What Is Possible with Current Technology?

    NASA Astrophysics Data System (ADS)

    Barrie, C. D.; Kasson, A.

    2014-12-01

    With ever increasing exploration and exploitation of 'unconventional' hydrocarbon resources, the drive to understand the origins, history and importance of these resources and their effects on the surrounding environment (i.e. ground waters) has never been more important. High-throughput, high-precision isotopic measurements are therefore a key tool in this industry to both understand the gas generated and monitor the development and stability of wells through time. With the advent of cavity ringdown spectroscopy (CRDS) instrumentation, there has been a push in some applications - environmental & atmospheric - to gather more and more data directly at the location of collection or at dedicated field stations. Furthermore, CRDS has resulted in users seeking greater autonomy of instrumentation and so-called black box technology. Traditionally IRMS technology has not met any of these demands, requiring very specific and extensive footprint, power and environmental requirements. This has meant that the 'Oil & Gas' sector, which for natural gases measurements requires GC-IRMS technology - not possible via CRDS - loses time, money and manpower as samples get sent to central facility or contract labs with potentially long lee times. However, recent developments in technology mean that IRMS systems exist which are benchtop, have much lower power requirements, standard power connections and as long as housed in a temperature controlled field stations can be deployed anywhere. Furthermore, with advances in electronics and software IRMS systems are approaching the black box level of newer instrumentation while maintaining the flexibility and abilities of isotope ratio mass spectrometry. This presentation will outline changes in IRMS technology applicable to the Oil & Gas industry, discuss the feasibility of true 'field' deployability and present results from a range of Oil & Gas samples.

  14. An analytic function expansion approach to computing perturbations from extreme-mass-ratio binaries with eccentric orbits

    NASA Astrophysics Data System (ADS)

    Evans, Charles; Forseth, Erik; Hopper, Seth

    2015-04-01

    Several groups (Fujita 2012; Shah, Friedman, and Whiting 2014; Shah 2014; Fujita 2014) have recently described results from computing gravitational perturbations and the self-force at extraordinarily high precision for binaries with circular orbits in the extreme-mass-ratio limit. These calculations have allowed comparison with post-Newtonian (PN) theory at the lowest order in the mass ratio and uncovered new terms and coefficients in the PN expansion for circular orbits. We describe a new means of extending this analytic function expansion approach to include binaries with eccentric orbits, thus allowing terms in the known 3PN order expansion to be verified and to discover new terms beyond 3PN.

  15. Semi-Quantitative Strain Ratio in the Differential Diagnosis of Breast Masses: Measurements Using One Region-of-Interest.

    PubMed

    Yoon, Jung Hyun; Song, Mi Kyung; Kim, Eun-Kyung

    2016-08-01

    The purpose of this study was to evaluate the diagnostic performances of semi-quantitative strain ratio measured by using one region-of-interest (ROI) on breast US elastography images. Two hundred one breast masses of 165 women (mean age: 47.2 y) were included. Ultrasonography (US) and elastography images of the masses were obtained and prospectively analyzed according to elasticity pattern, strain ratio, and final Breast Imaging-Reporting and Data System (BI-RADS) assessments. Of the 201 breast masses, 127 (63.2%) were benign and 74 (36.8%) were malignant. Elastography pattern and strain ratio (cut-off of 1.44) had significantly higher specificity than gray-scale US, 39.4% and 61.4% versus 29.1%, respectively (all p < 0.05). Area under the receiver operating characteristics curve (Az) was highest for gray-scale US (0.646), without statistical significances, than for elastography pattern (0.596, p = 0.159) or strain ratio (0.625, p = 0.610). Semi-quantitative strain ratio measured from one ROI has comparable diagnostic performances to gray-scale US, which may contribute to more accurate differential diagnosis of breast masses seen on US. PMID:27166015

  16. Orbit Processing and Analysis of a GEO Class of High Area-to-Mass Ratio Debris Objects

    NASA Astrophysics Data System (ADS)

    Kelecy, T.; Deiotte, R.; Africano, J.; Stansberry, G.; Payne, T.

    A population of recently discovered deep space objects is thought to be debris having origins from sources in the geosynchronous orbit (GEO) belt. Observations have been presented indicating that these objects have a high area-to-mass (A/M) ratio (1's to 10's of m2/kg), and thus would explain the observed migration of eccentricity (0.1-0.6) and inclination that distinguishes their orbital characteristics. There is a heightened interest in the international community due to the large number and small size of these objects, as they pose a hazard to active satellites operating in the vicinity of the GEO belt. Observational coverage of these objects has been limited by the orbital phasing and the locations of the tracking sites. Boeing, NASA and the U.S. Air Force Space Command have embarked on a collaborative effort with the Inter-Agency Space Debris Coordination Committee (IADC) to track selected high A/m of this population to more accurately characterize their orbits and orbit histories. Space Command tracking assets were tasked to provide angles measurements for representative set of 6 high A/m objects, and the data were used to establish a process for doing orbit updates that would accommodate a priori two-line element sets that will eventually be provided by the IADC. This paper presents the development and validation of the data processing and orbit update implementation, and preliminary analysis results of the high A/m class of objects. Limitations in the observational geometry, along with the apparent time variations in the nominal A/m values of some of the objects, pose a challenge for the orbit prediction. The ultimate goal is to establish a process that will provide long-term, relatively accurate orbital histories for these high A/m objects derived from a global set of observation metrics, and to capture photometric measurements when possible that will support characterization of these objects.

  17. Simultaneous stable carbon isotopic analysis of wine glycerol and ethanol by liquid chromatography coupled to isotope ratio mass spectrometry.

    PubMed

    Cabañero, Ana I; Recio, Jose L; Rupérez, Mercedes

    2010-01-27

    A novel procedure was established for the simultaneous characterization of wine glycerol and ethanol (13)C/(12)C isotope ratio, using liquid chromatography/isotope ratio mass spectrometry (LC-IRMS). Several parameters influencing separation of glycerol and ethanol from wine matrix were optimized. Results obtained for 35 Spanish samples exposed no significant differences and very strong correlations (r = 0.99) between the glycerol (13)C/(12)C ratios obtained by an alternative method (gas chromatography/isotope ratio mass spectrometry) and the proposed new methodology, and between the ethanol (13)C/(12)C ratios obtained by the official method (elemental analyzer/isotope ratio mass spectrometry) and the proposed new methodology. The accuracy of the proposed method varied from 0.01 to 0.19 per thousand, and the analytical precision was better than 0.25 per thousand. The new developed LC-IRMS method it is the first isotopic method that allows (13)C/(12)C determination of both analytes in the same run directly from a liquid sample with no previous glycerol or ethanol isolation, overcoming technical difficulties associated with complex sample treatment and improving in terms of simplicity and speed. PMID:20025274

  18. Evaluation of the 34S/32S ratio of Soufre de Lacq elemental sulfur isotopic reference material by continuous flow isotope-ratio mass spectrometry

    USGS Publications Warehouse

    Qi, H.P.; Coplen, T.B.

    2003-01-01

    Soufre de Lacq elemental sulfur reference material (IAEA-S-4) isotopically is homogeneous in amounts as small as 41 ??g as determined by continuous flow isotope-ratio mass spectrometry. The ??34S value for this reference material is +16.90 ?? 0.12??? (1??) on a scale (Vienna Can??on Diablo troilite, VCDT) where IAEA-S-1 Ag2S is -0.3??? and IAEA-S-2 Ag2S is +22.67???. Published by Elsevier Science B.V.

  19. Aerial observations of air masses transported from East Asia to the Western Pacific: Vertical structure of polluted air masses

    NASA Astrophysics Data System (ADS)

    Hatakeyama, Shiro; Ikeda, Keisuke; Hanaoka, Sayuri; Watanabe, Izumi; Arakaki, Takemitsu; Bandow, Hiroshi; Sadanaga, Yasuhiro; Kato, Shungo; Kajii, Yoshizumi; Zhang, Daizhou; Okuyama, Kikuo; Ogi, Takashi; Fujimoto, Toshiyuki; Seto, Takafumi; Shimizu, Atsushi; Sugimoto, Nobuo; Takami, Akinori

    2014-11-01

    There has been only limited information about the vertical chemical structure of the atmosphere, so far. We conducted aerial observations on 11, 12, and 14 December 2010 over the northern part of the East China Sea to analyze the spatial distribution of atmospheric pollutants from East Asia and to elucidate transformation processes of air pollutants during the long-range transport. On 11 December, a day on which Asian dust created hazy conditions, the average PM10 concentration was 40.69 μg m-3, and we observed high concentrations of chemical components such as Ca2+, NO3-, SO42-, Al, Ca, Fe, and Zn. The height of the boundary layer was about 1200 m, and most species of pollutants (except for dust particles and SO2) had accumulated within the boundary layer. In contrast, concentrations of pollutants were low in the boundary layer (up to 1000 m) on 12 December because clean Pacific air from the southeast had diluted the haze. However, we observed natural chemical components (Na+, Cl-, Al, Ca, and Fe) at 3000 m, the indication being that dust particles, including halite, were present in the lower free troposphere. On 14 December, peak concentrations of SO2 and black carbon were measured within the boundary layer (up to 700 m) and at 2300 m. The concentrations of anthropogenic chemical components such as NO3-, NH4+, and Zn were highest at 500 m, and concentrations of both anthropogenic and natural chemical components (SO42-, Pb, Ca2+, Ca, Al, and Fe) were highest at 2000 m. Thus, it was clearly indicated that the air above the East China Sea had a well-defined, layered structure below 3000 m.

  20. Variations of the glacio-marine air mass front in West Greenland through water vapor isotopes

    NASA Astrophysics Data System (ADS)

    Kopec, B. G.; Lauder, A. M.; Posmentier, E. S.; Feng, X.

    2012-12-01

    While the isotopic distribution of precipitation has been widely used for research in hydrology, paleoclimatology, and ecology for decades, intensive isotopic studies of atmospheric water vapor has only recently been made possible by spectral-based technology. New instrumentation based on this technology opens up many opportunities to investigate short-term atmospheric dynamics involving the water cycle and moisture transport. We deployed a Los Gatos Water Vapor Isotope Analyzer (WVIA) at Kangerlussuaq, Greenland from July 21 to August 15, and measured the water vapor concentration and its isotopic ratios continuously at 10s intervals. A Danish Meteorological Institute site is located about 1 km from the site of the deployment, and meteorological data is collected at 30 min intervals. During the observation period, the vapor concentration of the ambient air ranges from 5608.4 to 11189.4 ppm; dD and d18O range from -254.5 to -177.7 ‰ and -34.2 to -23.2 ‰, respectively. The vapor content (dew point) and the isotopic ratios are both strongly controlled by the wind direction. The easterly winds are associated with dry, isotopically depleted air masses formed over the glacier, while westerly winds are associated with moist and isotopically enriched air masses from the marine/fjord surface. This region typically experiences katabatic winds off of the ice sheet to the east. However, during some afternoons, the wind shifts 180 degrees, blowing off the fjord to the west. This wind switch marks the onset of a sea breeze, and significant isotopic enrichment results. Enrichment in deuterium is up to 60 ‰ with a mean of 15‰, and oxygen-18 is enriched by 3‰ on average and up to 8 ‰. Other afternoons have no change in wind, and only small changes in humidity and vapor isotopic ratios. The humidity and isotopic variations suggest the local atmosphere circulation is dominated by relatively high-pressure systems above the cold glaciers and cool sea surface, and diurnal

  1. A Tight Relation between N/O Ratio and Galaxy Stellar Mass Can Explain the Evolution of Strong Emission Line Ratios with Redshift

    NASA Astrophysics Data System (ADS)

    Masters, Daniel; Faisst, Andreas; Capak, Peter

    2016-09-01

    The offset of high-redshift star-forming galaxies in the [O iii]/Hβ versus [N ii]/Hα (O3N2) diagram in comparison with the local star-forming galaxy sequence is now well established. The physical origin of the shift is the subject of some debate and has important implications for metallicity measurements based on strong lines at all redshifts. To investigate the origin of the O3N2 offset, we use a sample of ˜100,000 star-forming galaxies from the Sloan Digital Sky Survey DR12 to understand how measurable galaxy physical properties ({{{Σ }}}{SFR}, ionization parameter, nitrogen-to-oxygen (N/O) ratio, and stellar mass) drive galaxy position in two key diagnostic diagrams: O3N2 and [O iii]/Hβ versus [S ii]/Hα (O3S2). At fixed [O iii]/Hβ, galaxies close to the high-redshift locus in O3N2 have higher {{{Σ }}}{SFR}, stellar mass, and N/O ratio. We conclude that higher N/O ratios at fixed [O iii]/Hβ are the proximate cause of the O3N2 shift. We also find a tight correspondence in the distributions of stellar mass and N/O in the diagnostic diagrams. This relation, spanning a range of galaxy evolutionary states, suggests that the N/O–M * relation is more fundamental than the relation between N/O and O/H. We argue that a more fundamental N/O–M * relation is well-motivated physically. Because the mass–metallicity relation evolves more rapidly with redshift than N/O–M *, the N/O ratios of high-redshift galaxies are elevated in comparison with local galaxies with the same gas-phase O/H. The O3N2 shift and elevated N/O ratios observed in high-redshift galaxies, therefore, come about as a natural consequence of the N/O–M * relation combined with the evolution of the mass–metallicity relation.

  2. Chemical compositions and radiative properties of dust and anthropogenic air masses study in Taipei Basin, Taiwan, during spring of 2004

    NASA Astrophysics Data System (ADS)

    Chang, Shih-Yu; Fang, Guor-Cheng; Chou, Charles C.-K.; Chen, Wei-Nai

    Asia is one of the major sources of not only mineral dust but also anthropogenic aerosols. Continental air masses associated with the East Asian winter monsoon always contain high contents of mineral dust and anthropogenic species and transported southeastward to Taiwan, which have significant influences on global atmospheric radiation transfer directly by scattering and absorbing solar radiation in each spring. However, few measurements for the long-range transported aerosol and its optical properties were announced in this area, between the Western Pacific and the southeastern coast of Mainland China. The overall objective of this work is to quantify the optical characteristics of different aerosol types in the Eastern Asian. In order to achieve this objective, meteorological parameters, concentrations of PM 10 and its soluble species, and optical property of atmospheric scattering coefficients were measured continuously with 1 h time-resolved from 11 February to 7 April 2004 in Taipei Basin (25°00'N, 121°32'E). In this work, the dramatic changes of meteorological parameters such as temperature and winds were used to determine the influenced period of each air mass. Continental, strong continental, marine, and stagnant air masses defined by the back-trajectory analysis and local meteorology were further characterized as long-range transport pollution, dust, clean marine, and local pollution aerosols, respectively, according to the diagnostic ratios. The aerosol mass scattering efficiency of continental pollution, dust, clean marine, and local pollution aerosols were ranged from 1.3 to 1.6, 0.7 to 1.0, 1.4 and 1.4 to 2.3 m 2 g -1, respectively. Overall, there are two distinct populations of aerosol mass scattering efficiencies, one for an aerosol chemical composition dominated by dust (<1.0 m 2 g -1) and the other for an aerosol chemical composition dominated by anthropogenic pollutants (1.3-2.3 m 2 g -1), which were similar to the previous measurements with

  3. Effect of Mach number, valve angle and length to diameter ratio on thermal performance in flow of air through Ranque Hilsch vortex tube

    NASA Astrophysics Data System (ADS)

    Devade, Kiran D.; Pise, Ashok T.

    2016-04-01

    Ranque Hilsch vortex tube is a device that can produce cold and hot air streams simultaneously from pressurized air. Performance of vortex tube is influenced by a number of geometrical and operational parameters. In this study parametric analysis of vortex tube is carried out. Air is used as the working fluid and geometrical parameters like length to diameter ratio (15, 16, 17, 18), exit valve angles (30°-90°), orifice diameters (5, 6 and 7 mm), 2 entry nozzles and tube divergence angle 4° is used for experimentation. Operational parameters like pressure (200-600 kPa), cold mass fraction (0-1) is varied and effect of Mach number at the inlet of the tube is investigated. The vortex tube is tested at sub sonic (0 < Ma < 1), sonic (Ma = 1) and supersonic (1 < Ma < 2) Mach number, and its effect on thermal performance is analysed. As a result it is observed that, higher COP and low cold end temperature is obtained at subsonic Ma. As CMF increases, COP rises and cold and temperature drops. Optimum performance of the tube is observed for CMF up to 0.5. Experimental correlations are proposed for optimum COP. Parametric correlation is developed for geometrical and operational parameters.

  4. Ratios of regioisomers of minor acylglycerols less polar than triricinolein in castor oil estimated by mass spectrometry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have recently reported the identification of forty new minor molecular species of acylglycerols containing hydroxy fatty acids less polar than triricinolein by electrospray ionization mass spectrometry of the lithium adducts. The ratios of regioisomers of triacylglycerols (ABC and AAB types) and ...

  5. Spatially tracking 13C labeled substrate (bicarbonate) accumulation in microbial communities using laser ablation isotope ratio mass spectrometry

    SciTech Connect

    Moran, James J.; Doll, Charles G.; Bernstein, Hans C.; Renslow, Ryan S.; Cory, Alexandra B.; Hutchison, Janine R.; Lindemann, Stephen R.; Fredrickson, Jim K.

    2014-08-25

    This is a manuscript we would like to submit for publication in Environmental Microbiology Reports. This manuscript contains a description of a laser ablation isotope ratio mass spectrometry methodology developed at PNNL and applied to a microbial system at a PNNL project location – Hot Lake, Washington. I will submit a word document containing the entire manuscript with this Erica input request form.

  6. Ratios of regioisomers of minor acylglycerols less polar than triricinolein in castor oil estimated by mass spectrometry (Abstract)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ratios of regioisomers of triacylglycerols (TAG) have been estimated by mass spectrometry using the fact that the neutral loss of fatty acid (FA) from the sn-2 position is energetically less favored in comparison with that from sn-1,3 positions. However regioisomeric TAG standards were needed fo...

  7. Thin-Film Air-Mass-Flow Sensor of Improved Design Developed

    NASA Technical Reports Server (NTRS)

    Fralick, Gustave C.; Wrbanek, John D.; Hwang, Danny P.

    2003-01-01

    Researchers at the NASA Glenn Research Center have developed a new air-mass-flow sensor to solve the problems of existing mass flow sensor designs. NASA's design consists of thin-film resistors in a Wheatstone bridge arrangement. The resistors are fabricated on a thin, constant-thickness airfoil to minimize disturbance to the airflow being measured. The following photograph shows one of NASA s prototype sensors. In comparison to other air-mass-flow sensor designs, NASA s thin-film sensor is much more robust than hot wires, causes less airflow disturbance than pitot tubes, is more accurate than vane anemometers, and is much simpler to operate than thermocouple rakes. NASA s thin-film air-mass-flow sensor works by converting the temperature difference seen at each leg of the thin-film Wheatstone bridge into a mass-flow rate. The following figure shows a schematic of this sensor with air flowing around it. The sensor operates as follows: current is applied to the bridge, which increases its temperature. If there is no flow, all the arms are heated equally, the bridge remains in balance, and there is no signal. If there is flow, the air passing over the upstream legs of the bridge reduces the temperature of the upstream legs and that leads to reduced electrical resistance for those legs. After the air has picked up heat from the upstream legs, it continues and passes over the downstream legs of the bridge. The heated air raises the temperature of these legs, increasing their electrical resistance. The resistance difference between the upstream and downstream legs unbalances the bridge, causing a voltage difference that can be amplified and calibrated to the airflow rate. Separate sensors mounted on the airfoil measure the temperature of the airflow, which is used to complete the calculation for the mass of air passing by the sensor. A current application for air-mass-flow sensors is as part of the intake system for an internal combustion engine. A mass-flow sensor is

  8. A five-collector system for the simultaneous measurement of argon isotope ratios in a static mass spectrometer

    USGS Publications Warehouse

    Stacey, J.S.; Sherrill, N.D.; Dalrymple, G.B.; Lanphere, M.A.; Carpenter, N.V.

    1981-01-01

    A system is described that utilizes five separate Faraday-cup collector assemblies, aligned along the focal plane of a mass spectrometer, to collect simultaneous argon ion beams at masses 36-40. Each collector has its own electrometer amplifier and analog-to-digital measuring channel, the outputs of which are processed by a minicomputer that also controls the mass spectrometer. The mass spectrometer utilizes a 90?? sector magnetic analyzer with a radius of 23 cm, in which some degree of z-direction focussing is provided for all the ion beams by the fringe field of the magnet. Simultaneous measurement of the ion beams helps to eliminate mass-spectrometer memory as a significant source of measurement error during an analysis. Isotope ratios stabilize between 7 and 9 s after sample admission into the spectrometer, and thereafter changes in the measured ratios are linear, typically to within ??0.02%. Thus the multi-collector arrangement permits very short extrapolation times for computation of initial ratios, and also provides the advantages of simultaneous measurement of the ion currents in that errors due to variations in ion beam intensity are minimized. A complete analysis takes less than 10 min, so that sample throughput can be greatly enhanced. In this instrument, the factor limiting analytical precision now lies in short-term apparent variations in the interchannel calibration factors. ?? 1981.

  9. Predicting plant uptake of organic chemicals from soil or air using octanol/water and octanol/air partition ratios and a molecular connectivity index

    SciTech Connect

    Dowdy, D.L.; McKone, T.E.

    1997-12-01

    A bioconcentration ratio (BCR) represents the ratio of the concentration of a chemical found in an exposed biological system, such as a plant or fish, to the concentration in the exposure medium (water, soil, or air). A comparison is made of the precision and accuracy of the molecular connectivity index (MCI) and the octanol/water partition coefficient (K{sub ow}) as predictors of BCRs from the soil matrix into above- or below-ground vegetation tissues. Calculated octanol/air partition coefficient (K{sub oa}) values are compared with calculated K{sub ow} and MCI values as predictors of measured air-to-plant BCRs. Based on a statistical evaluation of explained variance, residual error, and cross-validation, this evaluation reveals that the MCI provides higher precision, greater ease of use, and a more cost-effective method for predicting the potential bioconcentration of a chemical from soil into above-ground vegetation. Statistical analyses of the various methods reveal that both the K{sub ow} and MCI approaches have a similar level of precision for predicting BCRs from soil solution into roots and, among MCI, K{sub oa} and K{sub ow}; K{sub oa} is somewhat more precise and valid than MCI and K{sub ow} for estimating uptake, but all have limited accuracy as bioconcentration predictors. These latter results are derived mainly from the paucity of both reliable K{sub oa} values and measured air-to-plant BCRs and indicate a need for more experimental measurements from which more accurate models may be developed.

  10. Numerical modeling on air quality in an urban environment with changes of the aspect ratio and wind direction.

    PubMed

    Yassin, Mohamed F

    2013-06-01

    Due to heavy traffic emissions within an urban environment, air quality during the last decade becomes worse year by year and hazard to public health. In the present work, numerical modeling of flow and dispersion of gaseous emissions from vehicle exhaust in a street canyon were investigated under changes of the aspect ratio and wind direction. The three-dimensional flow and dispersion of gaseous pollutants were modeled using a computational fluid dynamics (CFD) model which was numerically solved using Reynolds-averaged Navier-Stokes (RANS) equations. The diffusion flow field in the atmospheric boundary layer within the street canyon was studied for different aspect ratios (W/H=1/2, 3/4, and 1) and wind directions (θ=90°, 112.5°, 135°, and 157.5°). The numerical models were validated against wind tunnel results to optimize the turbulence model. The numerical results agreed well with the wind tunnel results. The simulation demonstrated that the minimum concentration at the human respiration height within the street canyon was on the windward side for aspect ratios W/H=1/2 and 1 and wind directions θ=112.5°, 135°, and 157.5°. The pollutant concentration level decreases as the wind direction and aspect ratio increase. The wind velocity and turbulence intensity increase as the aspect ratio and wind direction increase. PMID:23192299

  11. Assessment of Reliability when Using Diagnostic Binary Ratios of Polycyclic Aromatic Hydrocarbons in Ambient Air PM10.

    PubMed

    Pongpiachan, Siwatt

    2015-01-01

    The reliability of using diagnostic binary ratios of particulate carcinogenic polycyclic aromatic hydrocarbons (PAHs) as chemical tracers for source characterisation was assessed by collecting PM10 samples from various air quality observatory sites in Thailand. The major objectives of this research were to evaluate the effects of day and night on the alterations of six different PAH diagnostic binary ratios: An/(An + Phe), Fluo/(Fluo + Pyr), B[a]A/(B[a]A + Chry), B[a]P/(B[a]P + B[e]P), Ind/(Ind + B[g,h,i]P), and B[k]F/Ind, and to investigate the impacts of site-specific conditions on the alterations of PAH diagnostic binary ratios by applying the concept of the coefficient of divergence (COD). No significant differences between day and night were found for any of the diagnostic binary ratios of PAHs, which indicates that the photodecomposition process is of minor importance in terms of PAH reduction. Interestingly, comparatively high values of COD for An/(An + Phe) in PM10 collected from sites with heavy traffic and in residential zones underline the influence of heterogeneous reactions triggered by oxidising gaseous species from vehicular exhausts. Therefore, special attention must be paid when interpreting the data of these diagnostic binary ratios, particularly for cases of low-molecular-weight PAHs. PMID:26745124

  12. Internal combustion engine cylinder-to-cylinder balancing with balanced air-fuel ratios

    DOEpatents

    Harris, Ralph E.; Bourn, Gary D.; Smalley, Anthony J.

    2006-01-03

    A method of balancing combustion among cylinders of an internal combustion engine. For each cylinder, a normalized peak firing pressure is calculated as the ratio of its peak firing pressure to its combustion pressure. Each cylinder's normalized peak firing pressure is compared to a target value for normalized peak firing pressure. The fuel flow is adjusted to any cylinder whose normalized peak firing pressure is not substantially equal to the target value.

  13. Treatment of drinking water residuals: comparing sedimentation and dissolved air flotation performance with optimal cation ratios.

    PubMed

    Bourgeois, J C; Walsh, M E; Gagnon, G A

    2004-03-01

    Spent filter backwash water (SFBW) and clarifier sludge generally comprise the majority of the waste residual volume generated and in relative terms, these can be collectively referred to as combined filter backwash water (CFBW). CFBW is essentially a low-solids wastewater with metal hydroxide flocs that are typically light and slow to settle. This study evaluates the impact of adding calcium and magnesium carbonates to CFBW in terms of assessing the impacts on the sedimentation and DAF separation processes. Representative CFBW samples were collected from two surface water treatment plants (WTP): Lake Major WTP (Dartmouth, Nova Scotia, Canada) and Victoria Park WTP (Truro, Nova Scotia, Canada). Bench-scale results indicated that improvements in the CFBW settled water quality could be achieved through the addition of the divalent cations, thereby adjusting the monovalent to divalent (M:D) ratios of the wastewater. In general, the DAF process required slightly higher M:D ratios than the sedimentation process. The optimum M:D ratios for DAF and sedimentation were determined to be 1:1 and 0.33:1, respectively. It was concluded that the optimisation of the cation balance between monovalent cations (e.g., Na(+), K(+)) and added divalent cations (i.e., Ca(2+), Mg(2+)) aided in the settling mechanism through charge neutralisation-precipitation. The increase in divalent cation concentrations within the waste residual stream promoted destabilisation of the negatively charged colour molecules within the CFBW, thereby causing the colloidal content to become more hydrophobic. PMID:14975650

  14. Air mass flow estimation in turbocharged diesel engines from in-cylinder pressure measurement

    SciTech Connect

    Desantes, J.M.; Galindo, J.; Guardiola, C.; Dolz, V.

    2010-01-15

    Air mass flow determination is needed for the control of current internal combustion engines. Current methods are based on specific sensors (as hot wire anemometers) or indirect estimation through manifold pressure. With the availability of cylinder pressure sensors for engine control, methods based on them can be used for replacing or complementing standard methods. Present paper uses in cylinder pressure increase during the intake stroke for inferring the trapped air mass. The method is validated on two different turbocharged diesel engines and compared with the standard methods. (author)

  15. Sex Ratio and Body Mass of Adult Herbivorous Beetles Depend on Time of Occurrence and Light Conditions

    PubMed Central

    Łukowski, Adrian; Mąderek, Ewa; Giertych, Marian J.; Karolewski, Piotr

    2015-01-01

    Body mass and sex ratio (F/M) of folivorous insects are easily measured parameters that are commonly used to assess the effect of food quality, living conditions, and preferences on the selection of favourable sites for offspring. A study was conducted on the polyphagous beetle, Gonioctena quinquepunctata (a pest of the native Prunus padus and alien P. serotina) and on the monophagous beetle, Altica brevicollis coryletorum (a pest of Corylus avellana). Both species have a similar life cycle with emergence of current-year adults in summer, and reproduction of 1-year-old insects in spring. A. brevicollis coryletorum feeds primarily on sunlit shrubs, while G. quinquepunctata prefers shaded leaves. The present study assessed the effect of time of occurrence (insect age) on body mass in both sexes and on the sex ratio F/M, taking into account the influence of light conditions associated with their favoured food source (sunlit vs. shaded leaves). We hypothesized that a change in body mass in current-year insects would be determined by the amount of consumed food, while the sex ratio would be stable, when in 1-year-old insects females would die shortly after oviposition, while males would be active for a prolonged time. Results confirmed the hypothesis that changes in mass of current-year beetles was determined by the amount of food intake. We also found that in spring, unfertilized females coexist with fertilized ones and that the latter females live for some time after oviposition; resulting in fluctuations of the mean mass for females. In both species, 1-year-old beetles were heavier than current-year. The preference of A. brevicollis coryletorum for sunlit leaves results in a higher body weight than in G. quinquepunctata in both seasons. The data are consistent and indicate seasonal fluctuations in body mass and changes in the sex ratio in 1-year-old beetles, due to the entrance into their reproductive period. PMID:26657564

  16. Sex Ratio and Body Mass of Adult Herbivorous Beetles Depend on Time of Occurrence and Light Conditions.

    PubMed

    Łukowski, Adrian; Mąderek, Ewa; Giertych, Marian J; Karolewski, Piotr

    2015-01-01

    Body mass and sex ratio (F/M) of folivorous insects are easily measured parameters that are commonly used to assess the effect of food quality, living conditions, and preferences on the selection of favourable sites for offspring. A study was conducted on the polyphagous beetle, Gonioctenaquinquepunctata (a pest of the native Prunus padus and alien P. serotina) and on the monophagous beetle, Alticabrevicollis coryletorum (a pest of Corylus avellana). Both species have a similar life cycle with emergence of current-year adults in summer, and reproduction of 1-year-old insects in spring. A. brevicollis coryletorum feeds primarily on sunlit shrubs, while G. quinquepunctata prefers shaded leaves. The present study assessed the effect of time of occurrence(insect age) on body mass in both sexes and on the sex ratio F/M, taking into account the influence of light conditions associated with their favoured food source (sunlit vs. shaded leaves). We hypothesized that a change in body mass in current-year insects would be determined by the amount of consumed food, while the sex ratio would be stable, when in 1-year-old insects females would die shortly after oviposition, while males would be active for a prolonged time. Results confirmed the hypothesis that changes in mass of current-year beetles was determined by the amount of food intake. We also found that in spring, unfertilized females coexist with fertilized ones and that the latter females live for some time after oviposition; resulting in fluctuations of the mean mass for females. In both species, 1-year-old beetles were heavier than current-year. The preference of A. brevicollis coryletorum for sunlit leaves results in a higher body weight than in G. quinquepunctata in both seasons. The data are consistent and indicate seasonal fluctuations in body mass and changes in the sex ratio in 1-year-old beetles, due to the entrance into their reproductive period. PMID:26657564

  17. Apparatus and method for generating large mass flow of high temperature air at hypersonic speeds

    NASA Technical Reports Server (NTRS)

    Sabol, A. P.; Stewart, R. B. (Inventor)

    1973-01-01

    High temperature, high mass air flow and a high Reynolds number test air flow in the Mach number 8-10 regime of adequate test flow duration is attained by pressurizing a ceramic-lined storage tank with air to a pressure of about 100 to 200 atmospheres. The air is heated to temperatures of 7,000 to 8,000 R prior to introduction into the tank by passing the air over an electric arc heater means. The air cools to 5,500 to 6,000 R while in the tank. A decomposable gas such as nitrous oxide or a combustible gas such as propane is injected into the tank after pressurization and the heated pressurized air in the tank is rapidly released through a Mach number 8-10 nozzle. The injected gas medium upon contact with the heated pressurized air effects an exothermic reaction which maintains the pressure and temperature of the pressurized air during the rapid release.

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

    NASA Astrophysics Data System (ADS)

    Ştefan, Sabina; Roman, Iuliana

    2015-06-01

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

  19. The Use of Red Green Blue (RGB) Air Mass Imagery to Investigate the Role of Stratospheric Air in a Non-Convective Wind Event

    NASA Technical Reports Server (NTRS)

    Berndt, Emily; Zavodsky, Bradley; Molthan, Andrew; Jedlovec, Gary

    2013-01-01

    AIRS ozone and model PV analysis confirm the stratospheric air in RGB Air Mass imagery. Trajectories confirm winds south of the low were distinct from CCB driven winds. Cross sections connect the tropopause fold, downward motion, and high nearsurface winds. Comparison to conceptual models show Shapiro-Keyser features and sting jet characteristics were observed in a storm that impacted the U.S. East Coast. RGB Air Mass imagery can be used to identify stratospheric air and regions susceptible to tropopause folding and attendant non-convective winds.

  20. Determination of the 2H/1H and 15N/14N ratios of Alkylpyrazines from coffee beans (Coffea arabica L. and Coffea canephoravar. robusta) by isotope ratio mass spectrometry.

    PubMed

    Richling, Elke; Preston, Christina; Kavvadias, Dominique; Kahle, Kathrin; Heppel, Christopher; Hummel, Silvia; König, Thorsten; Schreier, Peter

    2005-10-01

    The delta15N(AIR) and delta2H(VSMOW) data for several alkylpyrazines formed during the roasting process of coffee are reported. Samples of commercially available roasted (n = 9) as well as self-roasted (n = 8) coffee beans (Coffea arabica L. and Coffea canephora var. robusta) of different origins were investigated. By use of extracts prepared by simultaneous distillation extraction (SDE) and subsequently fractionated by liquid chromatography on silica gel, on-line capillary gas chromatography-isotope ratio mass spectrometry was employed in the combustion (C) and pyrolysis (P) modes (HRGC-C/P-IRMS) to determine the delta15N(AIR) and delta2H(VSMOW) values, respectively. In addition to the constituents of coffee beans, data for commercial synthetic alkylpyrazines and substances declared to be "natural" were determined. The delta15N(AIR) data for coffee alkylpyrazines under study-2-ethyl-5-methylpyrazine (1) and 2-ethyl-6-methylpyrazine (2) (measured as sum 1/2), 2-ethyl-3-methylpyrazine (3), 2-methylpyrazine (4), 2,5-dimethylpyrazine (5) and 2,6-dimethylpyrazine (6) (measured as sum 5/6), and 2,3-dimethylpyrazine (7), as well as 2,3,5-trimethylpyrazine (8)-varied in the range from +8.3 to -10.2 per thousand, thus revealing their biogeneration from amino acids (delta15N(AIR) ranging from +8 per thousand to -10 per thousand). The delta2H(VSMOW) values were determined in the range from -5 per thousand to -127 per thousand. Owing to the analytical differentiation observed between coffee alkylpyrazines and synthetic/"natural" samples of 3, 4, and 7, authenticity assessment of coffee-flavored products seems to be promising, provided that extended data will be available in the future. In the literature, there were no IRMS data available for the alkylpyrazines (1-8) under study. PMID:16190651

  1. Studies of waveform requirements for intermediate mass-ratio coalescence searches with advanced gravitational-wave detectors

    NASA Astrophysics Data System (ADS)

    Smith, R. J. E.; Mandel, I.; Vecchio, A.

    2013-08-01

    The coalescence of a stellar-mass compact object into an intermediate-mass black hole (intermediate mass-ratio coalescence; IMRAC) is an important astrophysical source for ground-based gravitational-wave interferometers in the so-called advanced (or second-generation) configuration. However, the ability to carry out effective matched-filter-based searches for these systems is limited by the lack of reliable waveforms. Here we consider binaries in which the intermediate-mass black hole has a mass in the range 24M⊙-200M⊙ with a stellar-mass companion having masses in the range 1.4M⊙-18.5M⊙. In addition, we constrain the mass ratios, q, of the binaries to be in the range 1/140≤q≤1/10 and we restrict our study to the case of circular binaries with nonspinning components. We investigate the relative contribution to the signal-to-noise ratio (SNR) of the three different phases of the coalescence—inspiral, merger and ringdown—using waveforms computed within the effective one-body formalism matched to numerical relativity. We show that merger and ringdown contribute to a substantial fraction of the total SNR over a large portion of the mass parameter space, although in a limited portion the SNR is dominated by the inspiral phase. We further identify three regions in the IMRAC mass space in which (i) inspiral-only searches could be performed with losses in detection rates L in the range 10%≲L≲27%, (ii) searches based on inspiral-only templates lead to a loss in detection rates in the range 27%≲L≲50%, and (iii) templates that include merger and ringdown are essential to prevent losses in detection rates greater than 50%. In addition we find that using inspiral-only templates as filters can lead to large biases in the estimates of the mass parameters of IMRACs. We investigate the effectiveness with which the inspiral-only portion of the IMRAC waveform space is covered by comparing several existing waveform families in this regime. We find that

  2. Black carbon over Mexico: The effect of atmospheric transport on mixing state, mass absorption cross-section, and BC/CO ratios

    SciTech Connect

    Subramanian, R.; Kok, G. L.; Baumgardner, Darrel; Clarke, A. D.; Shinozuka, Y.; Campos, Teresa; Heizer, CG; Stephens, Britton; de Foy, B.; Voss, Paul B.; Zaveri, Rahul A.

    2010-01-13

    A single particle soot photometer (SP2) was operated on the NCAR C-130 during the MIRAGE campaign (part of MILAGRO), sampling black carbon (BC) over Mexico. The highest BC concentrations were measured over Mexico City (sometimes as much as 2 Fg/m34 ) and over hill fires to the south of the city. The age of plumes outside of Mexico City was determined using a combination of HYSPLIT trajectories, WRF-FLEXPART modeling and CMET balloon tracks. As expected, older, diluted air masses had lower BC concentrations. A comparison of carbon monoxide (CO) and BC suggests a CO background of around 65 ppbv, and a backgroundcorrected BC/COnet ratio of 2.89±0.89 (ng/m39 -STP)/ppbv (average ± standard deviation). This ratio is similar for fresh emissions over Mexico City, as well as for aged airmasses. Comparison of light absorption measured with a particle soot absorption photometer (PSAP) and the SP2 BC suggests a BC mass-normalized absorption cross-section (MAC) of 10.9±2.1 m212 /g at 660 nm (or 13.1 m213 /g @ 550 nm, assuming MAC is inversely dependent on wavelength). This appears independent of aging and similar to the expected absorption cross-section for aged BC, but values, particularly in fresh emissions, could be biased high due to instrument artifacts. SP2-derived BC coating indicators show a prominent thinly-coated BC mode over the Mexico City Metropolitan Area (MCMA), while older air masses show both thinly-coated and thickly-coated BC. Some 2-day-old plumes do not show a prominent thickly-coated BC mode, possibly due to preferential wet scavenging of the likely-hydrophilic thickly-coated BC.

  3. Fundamental mass transfer model for indoor air emissions from surface coatings

    SciTech Connect

    Tichenor, B.A.; Guo, Z.; Sparks, L.E.

    1994-01-01

    The paper discusses the work of researchers at the U.S. EPA's Air and Energy Engineering Research Laboratory (Indoor Air Branch) who are evaluating mass transfer models based on fundamental principles to determine their effectiveness in predicting emissions from indoor architectural coatings. As a first step, a simple model based on Fick's Law of Diffusion has been developed. In the model, the mass transfer rate is assumed to be controlled by the boundary layer mass transfer coefficient, the saturation vapor pressure of the material being emitted, and the mass of volatile material remaining in the source at any point in time. Both static and dynamic chamber tests were conducted to obtain model validation data. Further validation experiments were conducted in a test house. Results of these tests are presented.

  4. International system of units traceable results of Hg mass concentration at saturation in air from a newly developed measurement procedure.

    PubMed

    Quétel, Christophe R; Zampella, Mariavittoria; Brown, Richard J C; Ent, Hugo; Horvat, Milena; Paredes, Eduardo; Tunc, Murat

    2014-08-01

    Data most commonly used at present to calibrate measurements of mercury vapor concentrations in air come from a relationship known as the "Dumarey equation". It uses a fitting relationship to experimental results obtained nearly 30 years ago. The way these results relate to the international system of units (SI) is not known. This has caused difficulties for the specification and enforcement of limit values for mercury concentrations in air and in emissions to air as part of national or international legislation. Furthermore, there is a significant discrepancy (around 7% at room temperature) between the Dumarey data and data calculated from results of mercury vapor pressure measurements in the presence of only liquid mercury. As an attempt to solve some of these problems, a new measurement procedure is described for SI traceable results of gaseous Hg concentrations at saturation in milliliter samples of air. The aim was to propose a scheme as immune as possible to analytical biases. It was based on isotope dilution (ID) in the liquid phase with the (202)Hg enriched certified reference material ERM-AE640 and measurements of the mercury isotope ratios in ID blends, subsequent to a cold vapor generation step, by inductively coupled plasma mass spectrometry. The process developed involved a combination of interconnected valves and syringes operated by computer controlled pumps and ensured continuity under closed circuit conditions from the air sampling stage onward. Quantitative trapping of the gaseous mercury in the liquid phase was achieved with 11.5 μM KMnO4 in 2% HNO3. Mass concentrations at saturation found from five measurements under room temperature conditions were significantly higher (5.8% on average) than data calculated from the Dumarey equation, but in agreement (-1.2% lower on average) with data based on mercury vapor pressure measurement results. Relative expanded combined uncertainties were estimated following a model based approach. They ranged from 2

  5. 13CO2/12CO2 ratio analysis in exhaled air by lead-salt tunable diode lasers for noninvasive diagnostics in gastroenterology

    NASA Astrophysics Data System (ADS)

    Stepanov, Eugene V.; Zyrianov, Pavel V.; Miliaev, Valerii A.; Selivanov, Yurii G.; Chizhevskii, Eugene G.; Os'kina, Svetlana; Ivashkin, Vladimir T.; Nikitina, Elena I.

    1999-07-01

    An analyzer of 13CO2/12CO2 ratio in exhaled air based on lead-salt tunable diode lasers is presented. High accuracy of the carbon isotope ratio detection in exhaled carbon dioxide was achieved with help of very simple optical schematics. It was based on the use of MBE laser diodes operating in pulse mode and on recording the resonance CO2 absorption at 4.2 micrometers . Special fast acquisition electronics and software were applied for spectral data collection and processing. Developed laser system was tested in a clinical train aimed to assessment eradication efficiency in therapy of gastritis associated with Helicobacter pylori infection. Data on the 13C-urea breath test used for P.pylori detection and obtained with tunable diode lasers in the course of the trail was compared with the results of Mass-Spectroscopy analysis and histology observations. The analyzer can be used also for 13CO2/12CO2 ratio detection in exhalation to perform gastroenterology breath test based on using other compounds labeled with stable isotopes.

  6. Molar gas ratios of air entrapped in ice: A new tool to determine the origin of relict massive ground ice bodies in permafrost

    NASA Astrophysics Data System (ADS)

    Cardyn, Raphaelle; Clark, Ian D.; Lacelle, Denis; Lauriol, Bernard; Zdanowicz, Christian; Calmels, Fabrice

    2007-09-01

    The molar ratios of atmospheric gases change during dissolution in water due to differences in their relative solubilities. We exploited this characteristic to develop a tool to clarify the origin of ice formations in permafrost regions. Extracted from ice, molar gas ratios can distinguish buried glacier ice from intrasedimental ground ice formed by freezing groundwaters. An extraction line was built to isolate gases from ice by melting and trapping with liquid He, followed by analysis of N 2, O 2,, Ar, 18O O2 and 15N N2, by continuous flow mass spectrometry. The method was tested using glacier ice, aufeis ice (river icing) and intrasedimental ground ice from sites in the Canadian Arctic. O 2/Ar and N 2/Ar ratios clearly distinguish between atmospheric gas in glacial ice and gases from intrasedimental ground ice, which are exsolved from freezing water. δ15N N2 and δ18O O2 in glacier ice, aufeis ice and intrasedimental ground ice do not show clear distinguishing trends as they are affected by various physical processes during formation such as gravitational settling, excess air addition, mixing with snow pack, and respiration.

  7. Effect of aspect ratio on the air forces and moments of harmonically oscillating thin rectangular wings in supersonic potential flow

    NASA Technical Reports Server (NTRS)

    Watkins, Charles E

    1951-01-01

    This report treats the effect of aspect ratio on the air forces and moments of an oscillating flat rectangular wing in supersonic potential flow. The linearized velocity potential for the wing undergoing sinusoidal torsional oscillations simultaneously with sinusoidal vertical translations is derived in the form of a power series in terms of a frequency parameter. The series development is such that the differential equation for the velocity potential is satisfied to the required power of the frequency parameter considered and the linear boundary conditions are satisfied exactly. The method of solution can be utilized for other plan forms, that is, plan forms for which certain steady-state solutions are known.

  8. Isotope ratios of uranium using high resolution inductively coupled plasma-mass spectrometry (ICP-MS)

    SciTech Connect

    Hearn, R.; Wildner, H.

    1998-12-31

    Actinide element isotope ratios have been determined in environmental samples using high resolution ICP-MS with ultrasonic nebulization. Precisions as low as 0.1% RSD have been achieved using various methods of acquisition. The methodology has been used for environmental monitoring of uranium isotope ratios as an indicator of nuclear activity. Also, it has been applied to calcite dating studies as a measure of past geochemical disturbances.

  9. Remote mass spectrometric sampling of electrospray- and desorption electrospray-generated ions using an air ejector.

    PubMed

    Dixon, R Brent; Bereman, Michael S; Muddiman, David C; Hawkridge, Adam M

    2007-10-01

    A commercial air ejector was coupled to an electrospray ionization linear ion trap mass spectrometer (LTQ) to transport remotely generated ions from both electrospray (ESI) and desorption electrospray ionization (DESI) sources. We demonstrate the remote analysis of a series of analyte ions that range from small molecules and polymers to polypeptides using the AE-LTQ interface. The details of the ESI-AE-LTQ and DESI-AE-LTQ experimental configurations are described and preliminary mass spectrometric data are presented. PMID:17716909

  10. Remote Mass Spectrometric Sampling of Electrospray- and Desorption Electrospray-Generated Ions Using an Air Ejector

    PubMed Central

    Dixon, R. Brent; Bereman, Michael S.; Muddiman, David C.; Hawkridge, Adam M.

    2007-01-01

    A commercial air ejector was coupled to an electrospray ionization linear ion trap mass spectrometer (LTQ) to transport remotely generated ions from both electrospray (ESI) and desorption electrospray ionization (DESI) sources. We demonstrate the remote analysis of a series of analyte ions that range from small molecules and polymers to polypeptides using the AE-LTQ interface. The details of the ESI-AE-LTQ and DESI-AE-LTQ experimental configurations are described and preliminary mass spectrometric data is presented. PMID:17716909

  11. Liquid and gas chromatography coupled to isotope ratio mass spectrometry for the determination of 13C-valine isotopic ratios in complex biological samples.

    PubMed

    Godin, Jean-Philippe; Breuillé, Denis; Obled, Christiane; Papet, Isabelle; Schierbeek, Henk; Hopfgartner, Gérard; Fay, Laurent-Bernard

    2008-10-01

    On-line gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) is commonly used to measure isotopic ratios at natural abundance as well as for tracer studies in nutritional and medical research. However, high-precision (13)C isotopic enrichment can also be measured by liquid chromatography-isotope ratio mass spectrometry (LC-IRMS). Indeed, LC-IRMS can be used, as shown by the new method reported here, to obtain a baseline separation and to measure (13)C isotopic enrichment of underivatised amino acids (Asp, Thr-Ser, Glu, Pro, Gly, Ala, Cys and Val). In case of Val, at natural abundance, the SD(delta(13)C) reported with this method was found to be below 1 per thousand . Another key feature of the new LC-IRMS method reported in this paper is the comparison of the LC-IRMS approach with the conventional GC-C-IRMS determination. To perform this comparative study, isotopic enrichments were measured from underivatised Val and its N(O, S)-ethoxycarbonyl ethyl ester derivative. Between 0.0 and 1.0 molar percent excess (MPE) (delta(13)C= -12.3 to 150.8 per thousand), the calculated root-mean-square (rms) of SD was 0.38 and 0.46 per thousand and the calculated rms of accuracy was 0.023 and 0.005 MPE, respectively, for GC-C-IRMS and LC-IRMS. Both systems measured accurately low isotopic enrichments (0.002 atom percent excess (APE)) with an SD (APE) of 0.0004. To correlate the relative (delta(13)C) and absolute (atom%, APE and MPE) isotopic enrichment of Val measured by the GC-C-IRMS and LC-IRMS devices, mathematical equations showing the slope and intercept of the curves were established and validated with experimental data between 0.0 to 2.3 MPE. Finally, both GC-C-IRMS and LC-IRMS instruments were also used to assess isotopic enrichment of protein-bound (13)C-Val in tibial epiphysis in a tracer study performed in rats. Isotopic enrichments measured by LC-IRMS and GC-C-IRMS were not statistically different (p>0.05). The results of this work indicate that

  12. Detection of counterfeit antiviral drug Heptodin and classification of counterfeits using isotope amount ratio measurements by multicollector inductively coupled plasma mass spectrometry (MC-ICPMS) and isotope ratio mass spectrometry (IRMS).

    PubMed

    Santamaria-Fernandez, Rebeca; Hearn, Ruth; Wolff, Jean-Claude

    2009-06-01

    Isotope ratio mass spectrometry (IRMS) and multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) are highly important techniques that can provide forensic evidence that otherwise would not be available. MC-ICP-MS has proved to be a very powerful tool for measuring high precision and accuracy isotope amount ratios. In this work, the potential of combining isotope amount ratio measurements performed by MC-ICP-MS and IRMS for the detection of counterfeit pharmaceutical tablets has been investigated. An extensive study for the antiviral drug Heptodin has been performed for several isotopic ratios combining MC-ICP-MS and an elemental analyser EA-IRMS for stable isotope amount ratio measurements. The study has been carried out for 139 batches of the antiviral drug and analyses have been performed for C, S, N and Mg isotope ratios. Authenticity ranges have been obtained for each isotopic system and combined to generate a unique multi-isotopic pattern only present in the genuine tablets. Counterfeit tablets have then been identified as those tablets with an isotopic fingerprint outside the genuine isotopic range. The combination of those two techniques has therefore great potential for pharmaceutical counterfeit detection. A much greater power of discrimination is obtained when at least three isotopic systems are combined. The data from these studies could be presented as evidence in court and therefore methods need to be validated to support their credibility. It is also crucial to be able to produce uncertainty values associated to the isotope amount ratio measurements so that significant differences can be identified and the genuineness of a sample can be assessed. PMID:19606588

  13. Binary neutron stars with generic spin, eccentricity, mass ratio, and compactness: Quasi-equilibrium sequences and first evolutions

    NASA Astrophysics Data System (ADS)

    Dietrich, Tim; Moldenhauer, Niclas; Johnson-McDaniel, Nathan K.; Bernuzzi, Sebastiano; Markakis, Charalampos M.; Brügmann, Bernd; Tichy, Wolfgang

    2015-12-01

    Information about the last stages of a binary neutron star inspiral and the final merger can be extracted from quasiequilibrium configurations and dynamical evolutions. In this article, we construct quasiequilibrium configurations for different spins, eccentricities, mass ratios, compactnesses, and equations of state. For this purpose we employ the sgrid code, which allows us to construct such data in previously inaccessible regions of the parameter space. In particular, we consider spinning neutron stars in isolation and in binary systems; we incorporate new methods to produce highly eccentric and eccentricity-reduced data; we present the possibility of computing data for significantly unequal-mass binaries with mass ratios q ≃2 ; and we create equal-mass binaries with individual compactness up to C ≃0.23 . As a proof of principle, we explore the dynamical evolution of three new configurations. First, we simulate a q =2.06 mass ratio which is the highest mass ratio for a binary neutron star evolved in numerical relativity to date. We find that mass transfer from the companion star sets in a few revolutions before merger and a rest mass of ˜10-2M⊙ is transferred between the two stars. This amount of mass accretion corresponds to ˜1051 ergs of accretion energy. This configuration also ejects a large amount of material during merger (˜7.6 ×1 0-2M⊙), imparting a substantial kick to the remnant neutron star. Second, we simulate the first merger of a precessing binary neutron star. We present the dominant modes of the gravitational waves for the precessing simulation, where a clear imprint of the precession is visible in the (2,1) mode. Finally, we quantify the effect of an eccentricity-reduction procedure on the gravitational waveform. The procedure improves the waveform quality and should be employed in future precision studies. However, one also needs to reduce other errors in the waveforms, notably truncation errors, in order for the improvement due to

  14. Assessment of Non-traditional Isotopic Ratios by Mass Spectrometry for Analysis of Nuclear Activities: Annual Report Year 2

    SciTech Connect

    Biegalski, S; Buchholz, B

    2009-08-26

    The objective of this work is to identify isotopic ratios suitable for analysis via mass spectrometry that distinguish between commercial nuclear reactor fuel cycles, fuel cycles for weapons grade plutonium, and products from nuclear weapons explosions. Methods will also be determined to distinguish the above from medical and industrial radionuclide sources. Mass spectrometry systems will be identified that are suitable for field measurement of such isotopes in an expedient manner. Significant progress has been made with this project within the past year: (1) Isotope production from commercial nuclear fuel cycles and nuclear weapons fuel cycles have been modeled with the ORIGEN and MCNPX codes. (2) MCNPX has been utilized to calculate isotopic inventories produced in a short burst fast bare sphere reactor (to approximate the signature of a nuclear weapon). (3) Isotopic ratios have been identified that are good for distinguishing between commercial and military fuel cycles as well as between nuclear weapons and commercial nuclear fuel cycles. (4) Mass spectrometry systems have been assessed for analysis of the fission products of interest. (5) A short-list of forensic ratios have been identified that are well suited for use in portable mass spectrometry systems.

  15. Lead isotope ratios in tree bark pockets: an indicator of past air pollution in the Czech Republic.

    PubMed

    Conkova, M; Kubiznakova, J

    2008-10-15

    Tree bark pockets were collected at four sites in the Czech Republic with differing levels of lead (Pb) pollution. The samples, spanning 1923-2005, were separated from beech (Fagus sylvatica) and spruce (Picea abies). Elevated Pb content (0.1-42.4 microg g(-1)) reflected air pollution in the city of Prague. The lowest Pb content (0.3-2.6 microg g(-1)) was found at the Kosetice EMEP "background pollution" site. Changes in (206)Pb/(207)Pb and (208)Pb/(206)Pb isotope ratios were in agreement with operation times of the Czech main anthropogenic Pb sources. Shortly after the Second World War, the (206)Pb/(207)Pb isotope ratio in bark pockets decreased from 1.17 to 1.14 and the (208)Pb/(206)Pb isotope ratio increased from 2.12 to 2.16. Two dominant emission sources responsible for these changes, lignite and leaded petrol combustion, contributed to the shifts in Pb isotope ratios. Low-radiogenic petrol Pb ((206)Pb/(207)Pb of 1.11) lead to lower (206)Pb/(207)Pb in bark pockets over time. High-radiogenic lignite-derived Pb ((206)Pb/(207)Pb of 1.18 to 1.19) was detected in areas affected by coal combustion rather than by traffic. PMID:18597820

  16. Emissions of an AVCO Lycoming 0-320-DIAD air cooled light aircraft engine as a function of fuel-air ratio, timing, and air temperature and humidity

    NASA Technical Reports Server (NTRS)

    Meng, P. R.; Skorobatckyi, M.; Cosgrove, D. V.; Kempke, E. E., Jr.

    1976-01-01

    A carbureted aircraft engine was operated over a range of test conditions to establish the exhaust levels over the EPA seven-mode emissions cycle. Baseline (full rich production limit) exhaust emissions at an induction air temperature of 59 F and near zero relative humidity were 90 percent of the EPA standard for HC, 35 percent for NOx, and 161 percent for CO. Changes in ignition timing around the standard 25 deg BTDC from 30 deg BTDC to 20 deg BTDC had little effect on the exhaust emissions. Retarding the timing to 15 deg BTDC increased both the HC and CO emissions and decreased NOx emissions. HC and CO emissions decreased as the carburetor was leaned out, while NOx emissions increased. The EPA emission standards were marginally achieved at two leanout conditions. Variations in the quantity of cooling air flow over the engine had no effect on exhaust emissions. Temperature-humidity effects at the higher values of air temperature and relative humidity tested indicated that the HC and CO emissions increased significantly, while the NOx emissions decreased.

  17. SENSOR FOR INDIVIDUAL BURNER CONTROL OF FIRING RATE, FUEL-AIR RATIO, AND COAL FINENESS CORRELATION

    SciTech Connect

    Wayne Hill; Roger Demler; Robert G. Mudry

    2004-10-01

    Instrumentation difficulties encountered in the previous reporting period were addressed early in this reporting period, resulting in a new instrumentation configuration that appears to be free of the noise issues found previously. This permitted the collection of flow calibration data to begin. The first issues in question are the effects of the type and location of the transducer mount. Data were collected for 15 different transducer positions (upstream and downstream of an elbow in the pipe), with both a stud mount and a magnetic transducer mount, for each of seven combinations of air and coal flow. Analysis of these data shows that the effects of the transducer mount type and location on the resulting dynamics are complicated, and not easily captured in a single analysis. To maximize the practical value of the calibration data, further detailed calibration data will be collected with both the magnetic and stud mounts, but at a single mounting location just downstream of a pipe elbow. This testing will be performed in the Coal Flow Test Facility in the next reporting period. The program progress in this reporting period was sufficient to put us essentially back on schedule.

  18. Body mass index, waist-to-hip ratio, waist circumference and waist-to-height ratio cannot predict male semen quality: a report of 1231 subfertile Chinese men.

    PubMed

    Lu, J-C; Jing, J; Dai, J-Y; Zhao, A Z; Yao, Q; Fan, K; Wang, G-H; Liang, Y-J; Chen, L; Ge, Y-F; Yao, B

    2015-11-01

    There were controversial results between obesity-associated markers and semen quality. In this study, we investigated the correlations between age, obesity-associated markers including body mass index (BMI), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR) and waist circumference (WC), the combination of age and obesity-associated markers, semen parameters and serum reproductive hormone levels in 1231 subfertile men. The results showed that BMI, WC, WHR and WHtR were positively related to age, and there were also positive relations between BMI, WHR, WC and WHtR and between sperm concentration (SC), total sperm count (TSC), progressive motility (PR), sperm motility and per cent of normal sperm morphology (NSM). However, age, each of obesity-associated markers and the combination of obesity-associated markers and age were unrelated to any of semen parameters including total normal-progressively motile sperm count (TNPMS). Age, BMI, WHR, WC and WHtR were negatively related to serum testosterone and SHBG levels. However, only serum LH and FSH levels were negatively related to sperm concentration, NSM and sperm motility. In a conclusion, although age and obesity have significant impacts on reproductive hormones such as testosterone, SHBG and oestradiol, semen parameters related to FSH and LH could not be influenced, indicating that obesity-associated markers could not predict male semen quality. PMID:25418484

  19. Extracting the Light Quark Mass Ratio m{sub u}/m{sub d} from Bottomonia Transitions

    SciTech Connect

    Guo Fengkun; Hanhart, Christoph; Meissner, Ulf-G.

    2010-10-15

    We propose a new method to extract the light quark mass ratio m{sub u}/m{sub d} using the {Upsilon}(4S){yields}h{sub b{pi}}{sup 0}({eta}) bottomonia transitions. The decay amplitudes are dominated by the light quark mass differences, and the corrections from other effects are rather small, allowing for a precise extraction. We also discuss how to reduce the theoretical uncertainty with the help of future experiments. As a by-product, we show that the decay {Upsilon}(4S){yields}h{sub b{eta}} is expected to be a nice channel for searching for the h{sub b} state.

  20. Utility of Ion Mobility Mass Spectrometry for Drug-to-Antibody Ratio Measurements in Antibody-Drug Conjugates

    NASA Astrophysics Data System (ADS)

    Huang, Richard Y.-C.; Deyanova, Ekaterina G.; Passmore, David; Rangan, Vangipuram; Deshpande, Shrikant; Tymiak, Adrienne A.; Chen, Guodong

    2015-06-01

    Antibody-drug conjugates (ADCs) are emerging modalities in the pharmaceutical industry. Characterization of ADC's drug-to-antibody ratio (DAR) becomes a key assessment because of its importance in ADC efficacy and safety. DAR characterization by conventional intact protein MS analysis, however, is challenging because of high heterogeneity of ADC samples. The analysis often requires protein deglycosylation, disulfide-bond reduction, or partial fragmentation. In this study, we illustrate the practical utility of ion mobility mass spectrometry (IM-MS) in a routine LC/MS workflow for DAR measurements. This strategy allows analyte "cleanup" in the gas phase, providing significant improvement of signal-to-noise ratios of ADC intact mass spectra for accurate DAR measurements. In addition, protein drift time analysis offers a new dimension in monitoring the changes of DAR in lot-to-lot analysis.

  1. Inert gas purgebox for Fourier transform ion cyclotron resonance mass spectrometry of air-sensitive solids

    NASA Astrophysics Data System (ADS)

    May, Michael A.; Marshall, Alan G.

    1994-03-01

    A sealed rigid ``purgebox'' makes it possible to load air- and/or moisture-sensitive solids into the solids probe inlet of a Fourier transform ion cyclotron resonance (FT/ICR) mass spectrometer. A pelletized sample is transferred (in a sealed canister) from a commercial drybox to a Lucite(R) purgebox. After the box is purged with inert gas, an attached glove manipulator is used to transfer the sample from the canister to the solids probe of the mass spectrometer. Once sealed inside the inlet, the sample is pre-evacuated and then passed into the high vacuum region of the instrument at ˜10-7 Torr. The purgebox is transparent, portable, and readily assembled/disassembled. Laser desorption FT/ICR mass spectra of the air- and moisture-sensitive solids, NbCl5. NbCl2(C5H5)2, and Zr(CH3)2(C5H5)2 are obtained without significant oxidation. The residual water vapor concentration inside the purgebox was measured as 100±20 ppm after a 90-min purge with dry nitrogen gas. High-resolution laser desorption/ionization mass spectrometry of air-sensitive solids becomes feasible with the present purgebox interface. With minor modification of the purgebox geometry, the present method could be adapted to any mass spectrometer equipped with a solid sample inlet.

  2. The Critical Mass Ratio of Double White Dwarf Binaries for Violent Merger-induced Type Ia Supernova Explosions

    NASA Astrophysics Data System (ADS)

    Sato, Yushi; Nakasato, Naohito; Tanikawa, Ataru; Nomoto, Ken’ichi; Maeda, Keiichi; Hachisu, Izumi

    2016-04-01

    Mergers of carbon–oxygen (CO) white dwarfs (WDs) are considered to be one of the potential progenitors of type Ia supernovae (SNe Ia). Recent hydrodynamical simulations showed that the less massive (secondary) WD violently accretes onto the more massive (primary) one, carbon detonation occurs, the detonation wave propagates through the primary, and the primary finally explodes as a sub-Chandrasekhar mass SN Ia. Such an explosion mechanism is called the violent merger scenario. Based on the smoothed particle hydrodynamics simulations of merging CO WDs, we derived a critical mass ratio (qcr) leading to the violent merger scenario that is more stringent than previous results. We conclude that this difference mainly comes from the differences in the initial condition of whether or not the WDs are synchronously spinning. Using our new results, we estimated the brightness distribution of SNe Ia in the violent merger scenario and compared it with previous studies. We found that our new qcr does not significantly affect the brightness distribution. We present the direct outcome immediately following CO WD mergers for various primary masses and mass ratios. We also discussed the final fate of the central system of the bipolar planetary nebula Henize 2-428, which was recently suggested to be a double CO WD system whose total mass exceeds the Chandrasekhar-limiting mass, merging within the Hubble time. Even considering the uncertainties in the proposed binary parameters, we concluded that the final fate of this system is almost certainly a sub-Chandrasekhar mass SN Ia in the violent merger scenario.

  3. Study of the extensive air shower mass sensitive parameters in prototype of ALBORZ array

    NASA Astrophysics Data System (ADS)

    Rastegarzadeh, G.; Nemati, M.

    2015-03-01

    In this work we have used muon production depth distribution as well as the lateral distribution of the secondary particles of Extensive Air Showers (EAS) as two main parameters to infer the mass composition of primary cosmic rays. In order to achieve a realistic estimate of the mass composition, a sample of showers initiated by proton and iron particles as primaries have been simulated by CORSIKA code with zenith angle between 0° and 18° and discrete energies in a range between 1014 and 1016 eV for ALBORZ (1200 m a.s.l, Tehran, Iran) and KASKADE (110 m a.s.l, Karlsruhe, Germany) observation levels. Moreover lateral density distribution functions of energy for charged particles of air showers have been proposed for both proton and Iron primaries. We have indicated that among these two EAS parameters, lateral distribution of secondary particles provides better mass discrimination.

  4. Airborne mass spectrometers: four decades of atmospheric and space research at the Air Force research laboratory.

    PubMed

    Viggiano, A A; Hunton, D E

    1999-11-01

    Mass spectrometry is a versatile research tool that has proved to be extremely useful for exploring the fundamental nature of the earth's atmosphere and ionosphere and in helping to solve operational problems facing the Air Force and the Department of Defense. In the past 40 years, our research group at the Air Force Research Laboratory has flown quadrupole mass spectrometers of many designs on nearly 100 sounding rockets, nine satellites, three Space Shuttles and many missions of high-altitude research aircraft and balloons. We have also used our instruments in ground-based investigations of rocket and jet engine exhaust, combustion chemistry and microwave breakdown chemistry. This paper is a review of the instrumentation and techniques needed for space research, a summary of the results from many of the experiments, and an introduction to the broad field of atmospheric and space mass spectrometry in general. PMID:10548806

  5. Estimating the Kernel Mass Ratio in Peanuts Nondestructively Using a Low-Cost Impedance Meter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Earlier, we investigated the possibility of estimating the mass of the kernels in a given volume of unshelled peanuts using a commercial impedance meter. Measurements of impedance and phase angles of peanut samples were made from 1 to 10 MHz at intervals of 1 MHz. The measured values were correlate...

  6. Ratios of regioisomers of triacylglycerols containing dihydroxy fatty acids in castor oil by mass spectrometry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The triacylglycerols (TAG) containing dihydroxy fatty acids have been recently identified by mass spectrometry in castor oil. These new dihydroxy fatty acids were proposed earlier as 11,12-dihydroxy-9-octadecenoic acid (diOH18:1), 11,12-dihydroxy-9,13-octadecadienoic acid (diOH18:2) and 11,12-dihydr...

  7. Indication of The High Mass-Transfer Ratio In S-Type Symbiotic Binaries

    NASA Astrophysics Data System (ADS)

    Shagatova, N.; Skopal, A.

    2015-12-01

    By modelling H0 column densities in eclipsing S-type symbiotic stars EG And and SY Mus, we derived the wind velocity profile and the corresponding mass-loss rate from their giants. Our analysis revealed a strong enhancement of the wind at the orbital plane.

  8. Application of Inductively Coupled Plasma Mass Spectrometry to the determination of uranium isotope ratios in individual particles for nuclear safeguards

    NASA Astrophysics Data System (ADS)

    Zhang, Xiao Zhi; Esaka, Fumitaka; Esaka, Konomi T.; Magara, Masaaki; Sakurai, Satoshi; Usuda, Shigekazu; Watanabe, Kazuo

    2007-10-01

    The capability of inductively coupled plasma mass spectrometry (ICP-MS) for the determination of uranium isotope ratios in individual particles was determined. For this purpose, we developed an experimental procedure including single particle transfer with a manipulator, chemical dissolution and isotope ratio analysis, and applied to the analysis of individual uranium particles in certified reference materials (NBL CRM U050 and U350). As the result, the 235U/ 238U isotope ratio for the particle with the diameter between 0.5 and 3.9 μm was successfully determined with the deviation from the certified ratio within 1.8%. The relative standard deviation (R.S.D.) of the 235U/ 238U isotope ratio was within 4.2%. Although the analysis of 234U/ 238U and 236U/ 238U isotope ratios gave the results with inferior precision, the R.S.D. within 20% was possible for the measurement of the particle with the diameter more than 2.1 μm. The developed procedure was successfully applied to the analysis of a simulated environmental sample prepared from a mixture of indoor dust (NIST SRM 2583) and uranium particles (NBL CRM U050, U350 and U950a). From the results, the proposed procedure was found to be an alternative analytical tool for nuclear safeguards.

  9. Air

    MedlinePlus

    ... do to protect yourself from dirty air . Indoor air pollution and outdoor air pollution Air can be polluted indoors and it can ... this chart to see what things cause indoor air pollution and what things cause outdoor air pollution! Indoor ...

  10. Extreme mass-ratio inspirals in the effective-one-body approach: Quasicircular, equatorial orbits around a spinning black hole

    SciTech Connect

    Yunes, Nicolas; Buonanno, Alessandra; Pan Yi; Barausse, Enrico; Hughes, Scott A.; Throwe, William; Miller, M. Coleman

    2011-02-15

    We construct effective-one-body waveform models suitable for data analysis with the Laser Interferometer Space Antenna for extreme mass-ratio inspirals in quasicircular, equatorial orbits about a spinning supermassive black hole. The accuracy of our model is established through comparisons against frequency-domain, Teukolsky-based waveforms in the radiative approximation. The calibration of eight high-order post-Newtonian parameters in the energy flux suffices to obtain a phase and fractional amplitude agreement of better than 1 rad and 1%, respectively, over a period between 2 and 6 months depending on the system considered. This agreement translates into matches higher than 97% over a period between 4 and 9 months, depending on the system. Better agreements can be obtained if a larger number of calibration parameters are included. Higher-order mass-ratio terms in the effective-one-body Hamiltonian and radiation reaction introduce phase corrections of at most 30 rad in a 1 yr evolution. These corrections are usually 1 order of magnitude larger than those introduced by the spin of the small object in a 1 yr evolution. These results suggest that the effective-one-body approach for extreme mass-ratio inspirals is a good compromise between accuracy and computational price for Laser Interferometer Space Antenna data-analysis purposes.

  11. Chemistry as a function of the fine-structure constant and the electron-proton mass ratio

    NASA Astrophysics Data System (ADS)

    King, Rollin A.; Siddiqi, Ali; Allen, Wesley D.; Schaefer, Henry F., III

    2010-04-01

    In standard computations in theoretical quantum chemistry the accepted values of the fundamental physical constants are assumed. Alternatively, the tools of computational quantum chemistry can be used to investigate hypothetical chemistry that would result from different values of these constants, given the same physical laws. In this work, the dependence of a variety of basic chemical quantities on the values of the fine-structure constant and the electron-proton mass ratio is explored. In chemistry, the accepted values of both constants may be considered small, in the sense that their increase must be substantial to seriously impact bond energies. It is found that if the fine-structure constant were larger, covalent bonds between light atoms would be weaker, and the dipole moment and hydrogen-bonding ability of water would be reduced. Conversely, an increase in the value of the electron-proton mass ratio increases dissociation energies in molecules such as H2, O2, and CO2. Specifically, a sevenfold increase in the fine-structure constant decreases the strength of the O-H bond in the water molecule by 7 kcal mol-1 while reducing its dipole moment by at least 10%, whereas a 100-fold increase in the electron-proton mass ratio increases the same bond energy by 11 kcal mol-1.

  12. Extreme mass-ratio inspirals in the effective-one-body approach: Quasicircular, equatorial orbits around a spinning black hole

    NASA Astrophysics Data System (ADS)

    Yunes, Nicolás; Buonanno, Alessandra; Hughes, Scott A.; Pan, Yi; Barausse, Enrico; Miller, M. Coleman; Throwe, William

    2011-02-01

    We construct effective-one-body waveform models suitable for data analysis with the Laser Interferometer Space Antenna for extreme mass-ratio inspirals in quasicircular, equatorial orbits about a spinning supermassive black hole. The accuracy of our model is established through comparisons against frequency-domain, Teukolsky-based waveforms in the radiative approximation. The calibration of eight high-order post-Newtonian parameters in the energy flux suffices to obtain a phase and fractional amplitude agreement of better than 1 rad and 1%, respectively, over a period between 2 and 6 months depending on the system considered. This agreement translates into matches higher than 97% over a period between 4 and 9 months, depending on the system. Better agreements can be obtained if a larger number of calibration parameters are included. Higher-order mass-ratio terms in the effective-one-body Hamiltonian and radiation reaction introduce phase corrections of at most 30 rad in a 1 yr evolution. These corrections are usually 1 order of magnitude larger than those introduced by the spin of the small object in a 1 yr evolution. These results suggest that the effective-one-body approach for extreme mass-ratio inspirals is a good compromise between accuracy and computational price for Laser Interferometer Space Antenna data-analysis purposes.

  13. Can we use the CO2 concentrations determined by continuous-flow isotope ratio mass spectrometry from small samples for the Keeling plot approach?

    PubMed

    Joos, Ottmar; Saurer, Matthias; Heim, Alexander; Hagedorn, Frank; Schmidt, Michael W I; Siegwolf, Rolf T W

    2008-12-01

    A common method to estimate the carbon isotopic composition of soil-respired air is to use Keeling plots (delta(13)C versus 1/CO2 concentration). This approach requires the precise determination of both CO2 concentration ([CO2]), usually measured with an infrared gas analyser (IRGA) in the field, and the analysis of delta(13)C by isotope ratio mass spectrometry (IRMS) in the laboratory. We measured [CO2] with an IRGA in the field (n = 637) and simultaneously collected air samples in 12 mL vials for analysis of the 13C values and the [CO2] using a continuous-flow isotope ratio mass spectrometer. In this study we tested if measurements by the IRGA and IRMS yielded the same results for [CO2], and also investigated the effects of different sample vial preparation methods on the [CO2] measurement and the thereby obtained Keeling plot results. Our results show that IRMS measurements of the [CO2] (during the isotope analysis) were lower than when the [CO2] was measured in the field with the IRGA. This is especially evident when the sample vials were not treated in the same way as the standard vials. From the three different vial preparation methods, the one using N2-filled and overpressurised vials resulted in the best agreement between the IRGA and IRMS [CO2] values. There was no effect on the (13)C-values from the different methods. The Keeling plot results confirmed that the overpressurised vials performed best. We conclude that in the cases where the ranges of [CO2] are large (>300 ppm; in our case it ranged between 70 and 1500 ppm) reliable estimation of the [CO2] with small samples using IRMS is possible for Keeling plot application. We also suggest some guidelines for sample handling in order to achieve proper results. PMID:19009520

  14. Vortex induction and mass entrainment in a small-aspect-ratio elliptic jet

    NASA Astrophysics Data System (ADS)

    Ho, Chih-Ming; Gutmark, Ephraim

    1987-06-01

    A passive technique of increasing entrainment was found by using a small-aspect-ratio elliptic jet. The entrainment ratio of an elliptic jet was several times greater than that of a circular jet or a plane jet. The self-induction of the asymmetric coherent structure caused azimuthal distortions which were responsible for engulfing large amounts of surrounding fluid into the jet. In an elliptic jet, an interesting feature in the initial stability process is that the thickness of the shear layer varies around the nozzle. The data indicated that instability frequency was scaled with the thinnest initial momentum thickness which was associated with the maximum vorticity. Turbulence properties were also examined and were found to be significantly different in the major- and minor-axis planes.

  15. Specific leaf mass, fresh: dry weight ratio, sugar and protein contents in species of Lamiaceae from different light environments.

    PubMed

    Castrillo, M; Vizcaino, D; Moreno, E; Latorraca, Z

    2005-01-01

    Samples from eleven species of Lamiaceae were collected from different light environments in Venezuela for laboratory analysis. The studied species were: Plectranthus scutellarioides (Ps), Scutellaria purpurascens (Sp), Hyptis pectinata (Hp)), H. sinuata (Hs). Leonorus japonicus (Lj), Plecthranthus amboinicus (Pa) Ocimum hasilicum (Ocb), O. campechianum (Occ) Origanum majorana (Orm), Rosmarinus officinali, (Ro) and Salvia officinalis (So). Protein and soluble sugar contents per unit of area were measured, Specific Leaf Mass (SLM) and fresh:dry weight (FW/DW) ratios were calculated. The higher values for soluble sugars contents were present in sun species: Lj, Pa, Ocb, Occ, Orm, Ro and So; the lower values were obtained in low light species: Ps, Sp, Hp, Hs. The values of protein content do not show any clear trend or difference between sun and shade environments. The lowest values for the fresh weight: dry weight ratio are observed in sun species with the exception of Lj and Pa, while the highest value is observed in Pa, a succulent plant. The higher values of specific leaf mass (SLM) (Kg DMm(-2)) are observed in sun plants. The two way ANOVA revealed that there were significant differences among species and between sun and low light environments for sugar content and FW:DW ratio. while SLM was significant for environments but no significant for species, and not significant for protein for both species and environments. The soluble sugar content, FW:DW ratio and SLM values obtained in this work, show a clear separation between sun and shade plants. The sugar content and FW:DW ratio are distinctive within the species, and the light environment affected sugar content. FW:DW ratio and SLM. These species may he shade-tolerant and able to survive in sunny environments. Perhaps these species originated in shaded environments and have been adapting to sunny habitats. PMID:17354417

  16. Mineralization of biogenic materials in the water masses of the South Atlantic Ocean. II: Stoichiometric ratios and mineralization rates

    NASA Astrophysics Data System (ADS)

    Álvarez-Salgado, X. A.; Álvarez, M.; Brea, S.; Mèmery, L.; Messias, M. J.

    2014-04-01

    The variability of nitrate (N), phosphate (P), silicate (Si) and Apparent Oxygen Utilization (AOU) due to water mass mixing was objectively separated from the variability due to mineralization of biogenic materials in the western and eastern South Atlantic Ocean on basis of the constrained Optimum MultiParameter (OMP) analysis implemented in the companion manuscript. Using a consensus linear regression model, AOU/N/P/Si mineralization ratios and the corresponding oxygen utilisation rates (OURs) were obtained for the realm of each water mass defined after the OMP analysis. Combining these results with a stoichiometric model, the organic carbon to nitrogen (C/N) ratios and the biochemical composition (carbohydrates + lipids, proteins and phosphorus compounds) of the mineralized material, were derived. The vertical variability of the AOU/N, AOU/P and AOU/C mineralization ratios pointed to a significant fractionation during the mineralization of sinking organic matter. This fractionation was confirmed by preferential consumption of organic phosphorous compounds and proteins in shallower levels, which produced an increase of the C/N ratio of the mineralised materials of 0.5 ± 0.2 mol C mol N-1 every 1000 dbar. OURs in the twilight zone decreased quadratically with the C/N molar ratio of the mineralised material and exponentially with pressure (p, in 103 dbar) according to the following regression equation: Ln (OUR) = 6.2(±1.2) - 2.0(±0.7) * Ln (C/N) - 0.6(±0.2) * p (r2 = 0.87, p < 0.006, n = 8). This variability in the rates and stoichiometric ratios of the biogenic material mineralization compromises our capacity to predict the ocean biogeochemistry response to global change, including the CO2 uptake and storage and the corresponding feedback mechanisms.

  17. Mass ratio of the 2 pc binary brown dwarf LUH 16 and limits on planetary companions from astrometry

    NASA Astrophysics Data System (ADS)

    Sahlmann, J.; Lazorenko, P. F.

    2015-10-01

    We analyse FORS2/VLT I-band imaging data to monitor the motions of both components in the nearest known binary brown dwarf WISE J104915.57-531906.1AB (LUH 16) over one year. The astrometry is dominated by parallax and proper motion, but with a precision of ˜0.2 mas per epoch we accurately measure the relative position change caused by the orbital motion of the pair. This allows us to directly measure a mass ratio of q = 0.78 ± 0.10 for this system. We also search for the signature of a planetary-mass companion around either of the A and B component and exclude at 3σ the presence of planets with masses larger than 2 MJ and orbital periods of 20-300 d. We update the parallax of LUH 16 to 500.51 ± 0.11 mas, i.e. just within 2 pc. This study yields the first direct constraint on the mass ratio of LUH 16 and shows that the system does not harbour any close-in giant planets.

  18. Mass ratio of the 2 pc binary brown dwarf LUH 16 and limits on planetary companions from astrometry

    NASA Astrophysics Data System (ADS)

    Sahlmann, Johannes; Lazorenko, Petro F.

    2016-01-01

    We analyse FORS2/VLT I-band imaging data to monitor the motions of both components in the nearest known binary brown dwarf WISE J104915.57-531906.1AB (LUH 16) over one year. The astrometry is dominated by parallax and proper motion, but with a precision of 0.2 mas per epoch we accurately measure the relative position change caused by the orbital motion of the pair. This allows us to directly measure a mass ratio of q = 0.78 ± 0.10 for this system. We also search for the signature of a planetary-mass companion around either of the A and B component and exclude at 3σ the presence of planets with masses larger than 2 MJ and orbital periods of 20-300 d. We update the parallax of LUH 16 to 500.51 ± 0.11 mas, i.e. just within 2 pc. This study yields the first direct constraint on the mass ratio of LUH 16 and shows that the system does not harbour any close-in giant planets.

  19. Atmospheric pollutants in Chiang Mai (Thailand) over a five-year period (2005-2009), their possible sources and relation to air mass movement

    NASA Astrophysics Data System (ADS)

    Chantara, Somporn; Sillapapiromsuk, Sopittaporn; Wiriya, Wan

    2012-12-01

    Monitoring and analysis of the chemical composition of air pollutants were conducted over a five-year period (2005-2009) in the sub-urban area of Chiang Mai, Thailand. This study aims to determine the seasonal variation of atmospheric ion species and gases, examine their correlations, identify possible sources and assess major air-flow patterns to the receptor. The dominant gas and particulate pollutants were NH3 (43-58%) and SO42- (39-48%), respectively. The annual mean concentrations of NH3 (μg m-3) in descending order were 4.08 (2009) > 3.32 (2007) > 2.68 (2008) > 2.47 (2006) and 1.87 (2005), while those of SO42- (μg m-3) were 2.60 (2007) > 2.20 (2006) > 1.95 (2009) > 1.75 (2008) and 1.26 (2005). Concentrations of particulate ions were analyzed by principle component analysis to find out the possible sources of air pollutants in this area. The first component of each year had a high loading of SO42- and NH4+, which probably came from fuel combustion and agricultural activity, respectively. K+, a tracer of biomass burning, also contributed to the first or the second components of each year. Concentrations of NH4+ and SO42- were well correlated (r > 0.777, p < 0.01), which lead to the conclusion that (NH4)2SO4 was a major compound present in this area. The 3-day backward trajectories of air mass arriving at Chiang Mai from 2005 to 2009 were analyzed using the hybrid single particle langrangian integrated trajectory (HYSPLIT) model and grouped by cluster analysis. The air mass data was analyzed for the dry season (n = 18; 100%). The trajectory of air mass in 2005 mainly originated locally (67%). In 2006, the recorded data showed that 56% of air mass was emitted from the western continental region of Thailand. In 2007, the percent ratios from the western and eastern continental areas were equal (39%). In 2008, 67% originated from the western continental area. In 2009, the recorded air mass mainly came from the western continental area (72%). In conclusion, the

  20. Sixteen Years of Ulysses Interstellar Dust Measurements in the Solar System. I. Mass Distribution and Gas-to-dust Mass Ratio

    NASA Astrophysics Data System (ADS)

    Krüger, Harald; Strub, Peter; Grün, Eberhard; Sterken, Veerle J.

    2015-10-01

    In the early 1990s, contemporary interstellar dust penetrating deep into the heliosphere was identified with the in situ dust detector on board the Ulysses spacecraft. Between 1992 and the end of 2007 Ulysses monitored the interstellar dust stream. The interstellar grains act as tracers of the physical conditions in the local interstellar medium (ISM) surrounding our solar system. Earlier analyses of the Ulysses interstellar dust data measured between 1992 and 1998 implied the existence of a population of “big” interstellar grains (up to 10-13 kg). The derived gas-to-dust-mass ratio was smaller than the one derived from astronomical observations, implying a concentration of interstellar dust in the very local ISM. In this paper we analyze the entire data set from 16 yr of Ulysses interstellar dust measurements in interplanetary space. This paper concentrates on the overall mass distribution of interstellar dust. An accompanying paper investigates time-variable phenomena in the Ulysses interstellar dust data, and in a third paper we present the results from dynamical modeling of the interstellar dust flow applied to Ulysses. We use the latest values for the interstellar hydrogen and helium densities, the interstellar helium flow speed of {v}{ISM∞ }=23.2 {km} {{{s}}}-1, and the ratio of radiation pressure to gravity, β, calculated for astronomical silicates. We find a gas-to-dust mass ratio in the local interstellar cloud of {R}{{g}/{{d}}}={193}-57+85, and a dust density of (2.1 ± 0.6) × 10-24 kg m-3. For a higher inflow speed of 26 {km} {{{s}}}-1, the gas-to-dust mass ratio is 20% higher, and, accordingly, the dust density is lower by the same amount. The gas-to-dust mass ratio derived from our new analysis is compatible with the value most recently determined from astronomical observations. We confirm earlier results that the very local ISM contains “big” (i.e., ≈1 μm sized) interstellar grains. We find a dust density in the local ISM that is a

  1. Establishing Lagrangian Connections between Observations within Air Masses Crossing the Atlantic during the ICARTT Experiment

    NASA Technical Reports Server (NTRS)

    Methven, J.; Arnold, S. R.; Stohl, A.; Evans, M. J.; Avery, M.; Law, K.; Lewis, A. C.; Monks, P. S.; Parrish, D.; Reeves, C.; Schlager, H.; Atlas, E.; Blake, D.; Coe, H.; Cohen, R. C.; Crosier, J.; Flocke, F.; Holloway, J. S.; Hopkins, J. R.; Huber, G.; McQuaid, J.; Purvis, R.; Rappengluck, B.; Ryerson, T. B.; Sachse, G. W.

    2006-01-01

    The International Consortium for Atmospheric Research on Transport and Transformation (ICARTT)-Lagrangian experiment was conceived with an aim to quantify the effects of photochemistry and mixing on the transformation of air masses in the free troposphere away from emissions. To this end attempts were made to intercept and sample air masses several times during their journey across the North Atlantic using four aircraft based in New Hampshire (USA), Faial (Azores) and Creil (France). This article begins by describing forecasts using two Lagrangian models that were used to direct the aircraft into target air masses. A novel technique is then used to identify Lagrangian matches between flight segments. Two independent searches are conducted: for Lagrangian model matches and for pairs of whole air samples with matching hydrocarbon fingerprints. The information is filtered further by searching for matching hydrocarbon samples that are linked by matching trajectories. The quality of these coincident matches is assessed using temperature, humidity and tracer observations. The technique pulls out five clear Lagrangian cases covering a variety of situations and these are examined in detail. The matching trajectories and hydrocarbon fingerprints are shown and the downwind minus upwind differences in tracers are discussed.

  2. Characterising terrestrial influences on Antarctic air masses using Radon-222 measurements at King George Island

    NASA Astrophysics Data System (ADS)

    Chambers, S. D.; Hong, S.-B.; Williams, A. G.; Crawford, J.; Griffiths, A. D.; Park, S.-J.

    2014-09-01

    We report on one year of high-precision direct hourly radon observations at King Sejong Station (King George Island) beginning in February 2013. Findings are compared with historic and ongoing radon measurements from other Antarctic sites. Monthly median concentrations reduced from 72 mBq m-3 in late-summer to 44 mBq m-3 in late winter and early spring. Monthly 10th percentiles, ranging from 29 to 49 mBq m-3, were typical of oceanic baseline values. Diurnal cycles were rarely evident and local influences were minor, consistent with regional radon flux estimates one tenth of the global average for ice-free land. The predominant fetch region for terrestrially influenced air masses was South America (47-53° S), with minor influences also attributed to aged Australian air masses and local sources. Plume dilution factors of 2.8-4.0 were estimated for the most terrestrially influenced (South American) air masses, and a seasonal cycle in terrestrial influence on tropospheric air descending at the pole was identified and characterised.

  3. Characterising terrestrial influences on Antarctic air masses using radon-222 measurements at King George Island

    NASA Astrophysics Data System (ADS)

    Chambers, S. D.; Hong, S.-B.; Williams, A. G.; Crawford, J.; Griffiths, A. D.; Park, S.-J.

    2014-05-01

    We report on one year of high precision direct hourly radon observations at King Sejong Station (King George Island) beginning in February 2013. Findings are compared with historic and ongoing radon measurements from other Antarctic sites. Monthly median concentrations reduced from 72 mBq m-3 in late summer to 44 mBq m-3 in late-winter and early-spring. Monthly 10th percentiles, ranging from 29 to 49 mBq m-3, were typical of oceanic baseline values. Diurnal cycles were rarely evident and local influences were minor, consistent with regional radon flux estimates one tenth of the global average for ice-free land. The predominant fetch region for terrestrially influenced air masses was South America (47-53° S), with minor influences also attributed to aged Australian air masses and local sources. Plume dilution factors of 2.8-4.0 were estimated for the most terrestrially influenced (South American) air masses, and a seasonal cycle in terrestrial influence on tropospheric air descending at the pole was identified and characterised.

  4. Effect of air temperature and relative humidity at various fuel-air ratios on exhaust emissions on a per-mode basis of an Avco Lycoming 0-320 DIAD light aircraft engine. Volume 2: Individual data points

    NASA Technical Reports Server (NTRS)

    Skorobatckyi, M.; Cosgrove, D. V.; Meng, P. R.; Kempke, E. R.

    1976-01-01

    A carbureted four cylinder air cooled 0-320 DIAD Lycoming aircraft engine was tested to establish the effects of air temperature and humidity at various fuel-air ratios on the exhaust emissions on a per-mode basis. The test conditions included carburetor lean-out at air temperatures of 50, 59, 80, and 100 F at relative humidities of 0, 30, 60, and 80 percent. Temperature-humidity effects at the higher values of air temperature and relative humidity tested indicated that the HC and CO emissions increased significantly, while the NOx emissions decreased. Even at a fixed fuel-air ratio, the HC emissions increase and the NOx emissions decrease at the higher values of air temperature and humidity. Volume II contains the data taken at each of the individual test points.

  5. Effect of Air Temperature and Relative Humidity at Various Fuel-Air Ratios on Exhaust Emissions on a Per-Mode Basis of an AVCO Lycoming 0-320 Diad Light Aircraft Engine: Volume 1: Results and Plotted Data

    NASA Technical Reports Server (NTRS)

    Skorobatckyi, M.; Cosgrove, D. V.; Meng, P. R.; Kempe, E. E., Jr.

    1978-01-01

    A carbureted four cylinder air cooled 0-320 DIAD Lycoming aircraft engine was tested to establish the effects of air temperature and humidity at various fuel-air ratios on the exhaust emissions on a per-mode basis. The test conditions include carburetor lean out at air temperatures of 50, 59, 80, and 100 F at relative humidities of 0, 30, 60, and 80 percent. Temperature humidity effects at the higher values of air temperature and relative humidity tested indicated that the HC and CO emissions increased significantly, while the NOx emissions decreased. Even at a fixed fuel air ratio, the HC emissions increase and the NOx emissions decrease at the higher values of air temperature and humidity.

  6. Stable isotope composition of waters in the Great Basin, United States 1. Air-mass trajectories

    USGS Publications Warehouse

    Friedman, I.; Harris, J.M.; Smith, G.I.; Johnson, C.A.

    2002-01-01

    Isentropic trajectories, calculated using the NOAA/Climate Monitoring and Diagnostics Laboratory's isentropic transport model, were used to determine air-parcel origins and the influence of air mass trajectories on the isotopic composition of precipitation events that occurred between October 1991 and September 1993 at Cedar City, Utah, and Winnemucca, Nevada. Examination of trajectories that trace the position of air parcels backward in time for 10 days indicated five distinct regions of water vapor origin: (1) Gulf of Alaska and North Pacific, (2) central Pacific, (3) tropical Pacific, (4) Gulf of Mexico, and (5) continental land mass. Deuterium (??D) and oxygen-18 (??18O) analyses were made of precipitation representing 99% of all Cedar City events. Similar analyses were made on precipitation representing 66% of the precipitation falling at Winnemucca during the same period. The average isotopic composition of precipitation derived from each water vapor source was determined. More than half of the precipitation that fell at both sites during the study period originated in the tropical Pacific and traveled northeast to the Great Basin; only a small proportion traversed the Sierra Nevada. The isotopic composition of precipitation is determined by air-mass origin and its track to the collection station, mechanism of droplet formation, reequilibration within clouds, and evaporation during its passage from cloud to ground. The Rayleigh distillation model can explain the changes in isotopic composition of precipitation as an air mass is cooled pseudo-adiabatically during uplift. However, the complicated processes that take place in the rapidly convecting environment of cumulonimbus and other clouds that are common in the Great Basin, especially in summer, require modification of this model because raindrops that form in the lower portion of those clouds undergo isotopic change as they are elevated to upper levels of the clouds from where they eventually drop to the

  7. Stable isotope composition of waters in the Great Basin, United States 1. Air-mass trajectories

    NASA Astrophysics Data System (ADS)

    Friedman, Irving; Harris, Joyce M.; Smith, George I.; Johnson, Craig A.

    2002-10-01

    Isentropic trajectories, calculated using the NOAA/Climate Monitoring and Diagnostics Laboratory's isentropic transport model, were used to determine air-parcel origins and the influence of air mass trajectories on the isotopic composition of precipitation events that occurred between October 1991 and September 1993 at Cedar City, Utah, and Winnemucca, Nevada. Examination of trajectories that trace the position of air parcels backward in time for 10 days indicated five distinct regions of water vapor origin: (1) Gulf of Alaska and North Pacific, (2) central Pacific, (3) tropical Pacific, (4) Gulf of Mexico, and (5) continental land mass. Deuterium (δD) and oxygen-18 (δ18O) analyses were made of precipitation representing 99% of all Cedar City events. Similar analyses were made on precipitation representing 66% of the precipitation falling at Winnemucca during the same period. The average isotopic composition of precipitation derived from each water vapor source was determined. More than half of the precipitation that fell at both sites during the study period originated in the tropical Pacific and traveled northeast to the Great Basin; only a small proportion traversed the Sierra Nevada. The isotopic composition of precipitation is determined by air-mass origin and its track to the collection station, mechanism of droplet formation, reequilibration within clouds, and evaporation during its passage from cloud to ground. The Rayleigh distillation model can explain the changes in isotopic composition of precipitation as an air mass is cooled pseudo-adiabatically during uplift. However, the complicated processes that take place in the rapidly convecting environment of cumulonimbus and other clouds that are common in the Great Basin, especially in summer, require modification of this model because raindrops that form in the lower portion of those clouds undergo isotopic change as they are elevated to upper levels of the clouds from where they eventually drop to the

  8. Optimal power-to-mass ratios when predicting flat and hill-climbing time-trial cycling.

    PubMed

    Nevill, A M; Jobson, S A; Davison, R C R; Jeukendrup, A E

    2006-07-01

    The purpose of this article was to establish whether previously reported oxygen-to-mass ratios, used to predict flat and hill-climbing cycling performance, extend to similar power-to-mass ratios incorporating other, often quick and convenient measures of power output recorded in the laboratory [maximum aerobic power (W(MAP)), power output at ventilatory threshold (W(VT)) and average power output (W(AVG)) maintained during a 1 h performance test]. A proportional allometric model was used to predict the optimal power-to-mass ratios associated with cycling speeds during flat and hill-climbing cycling. The optimal models predicting flat time-trial cycling speeds were found to be (W(MAP)m(-0.48))(0.54), (W(VT)m(-0.48))(0.46) and (W(AVG)m(-0.34))(0.58) that explained 69.3, 59.1 and 96.3% of the variance in cycling speeds, respectively. Cross-validation results suggest that, in conjunction with body mass, W(MAP) can provide an accurate and independent prediction of time-trial cycling, explaining 94.6% of the variance in cycling speeds with the standard deviation about the regression line, s=0.686 km h(-1). Based on these models, there is evidence to support that previously reported VO2-to-mass ratios associated with flat cycling speed extend to other laboratory-recorded measures of power output (i.e. Wm(-0.32)). However, the power-function exponents (0.54, 0.46 and 0.58) would appear to conflict with the assumption that the cyclists' speeds should be proportional to the cube root (0.33) of power demand/expended, a finding that could be explained by other confounding variables such as bicycle geometry, tractional resistance and/or the presence of a tailwind. The models predicting 6 and 12% hill-climbing cycling speeds were found to be proportional to (W(MAP)m(-0.91))(0.66), revealing a mass exponent, 0.91, that also supports previous research. PMID:16685550

  9. DIRECT TRACE ANALYSIS OF VOLATILE ORGANIC COMPOUNDS IN AIR USING ION TRAP MASS SPECTROMETERS WITH FILTERED NOISE FIELDS

    EPA Science Inventory

    Two ion trap mass spectrometers and direct air sampling interfaces are being evaluated in the laboratory for monitoring toxic air pollutants in real time. he mass spectrometers are the large, laboratory-based Finnigan MAT ion trap (ITMS) and the compact, field-deployable Teledyne...

  10. Detailed assessment of isotope ratio infrared spectroscopy and isotope ratio mass spectrometry for the stable isotope analysis of plant and soil waters

    NASA Astrophysics Data System (ADS)

    Zhao, L.; Xiao, H.; Zhou, J.; Wang, L.; Cheng, G.; Zhou, M.; Yin, L.; McCabe, M. F.

    2011-12-01

    As an alternative to isotope ratio mass spectrometry (IRMS) the isotope ratio infrared spectroscopy (IRIS) approach has the advantage of low cost, continuous measurement and capacity for field based application for the analysis of stable water isotopes. Recent studies have indicated that there are potential issues of organic contamination of the spectral signal in the IRIS method, resulting in errant readings for leaf samples. To gain a more thorough understanding of the effects of sample type (e.g., leaf, root, stem and soil), sample species, sampling time and climatic condition (dry vs. wet) on water isotope estimates using IRIS, we collected soil samples and plant components from a number of major species at a fine temporal resolution (every two hours for 24-48 hours) across three locations with different climatic conditions in the Heihe River Basin, China. The hydrogen and oxygen isotopic composition of the extracted water from these samples was measured using both an IRMS and IRIS instrument. Results show that the mean discrepancy between the IRMS and IRIS approach, for δ18O and δD respectively, was: -5.6% and -75.7% for leaf water; -4.0% and -23.3% for stem water; -3.4% and -28.2% for root water; -6.7% and -0.5% for xylem water; -0.06% and -0.3% for xylem flow; and -0.1% and 0.3% for soil water. The order of the discrepancy followed: leaf > stem ≈ root > xylem > xylem flow ≈ soil. In general, species of the same functional types (e.g., woody vs. herbaceous) within similar habitats showed similar deviations. For different functional types, the differences were large. Sampling during the nighttime did not remove the observed deviations.

  11. Detailed assessment of isotope ratio infrared spectroscopy and isotope ratio mass spectrometry for the stable isotope analysis of plant and soil waters.

    PubMed

    Zhao, Liangju; Xiao, Honglang; Zhou, Jian; Wang, Lixin; Cheng, Guodong; Zhou, Maoxian; Yin, Li; McCabe, Matthew F

    2011-10-30

    As an alternative to isotope ratio mass spectrometry (IRMS), the isotope ratio infrared spectroscopy (IRIS) approach has the advantage of low cost, continuous measurement and the capacity for field-based application for the analysis of the stable isotopes of water. Recent studies have indicated that there are potential issues of organic contamination of the spectral signal in the IRIS method, resulting in incorrect results for leaf samples. To gain a more thorough understanding of the effects of sample type (e.g., leaf, root, stem and soil), sample species, sampling time and climatic condition (dry vs. wet) on water isotope estimates using IRIS, we collected soil samples and plant components from a number of major species at a fine temporal resolution (every 2 h for 24-48 h) across three locations with different climatic conditions in the Heihe River Basin, China. The hydrogen and oxygen isotopic compositions of the extracted water from these samples were measured using both an IRMS and an IRIS instrument. The results show that the mean discrepancies between the IRMS and IRIS approaches for δ(18) O and δD, respectively, were: -5.6‰ and -75.7‰ for leaf water; -4.0‰ and -23.3‰ for stem water; -3.4‰ and -28.2‰ for root water; -0.5‰ and -6.7‰ for xylem water; -0.06‰ and -0.3‰ for xylem flow; and -0.1‰ and 0.3‰ for soil water. The order of the discrepancy was: leaf > stem ≈ root > xylem > xylem flow ≈ soil. In general, species of the same functional types (e.g., woody vs. herbaceous) within similar habitats showed similar deviations. For different functional types, the differences were large. Sampling at nighttime did not remove the observed deviations. PMID:21953962

  12. Discrepancies between isotope ratio infrared spectroscopy and isotope ratio mass spectrometry for the stable isotope analysis of plant and soil waters.

    PubMed

    West, Adam G; Goldsmith, Gregory R; Brooks, Paul D; Dawson, Todd E

    2010-07-30

    The use of isotope ratio infrared spectroscopy (IRIS) for the stable hydrogen and oxygen isotope analysis of water is increasing. While IRIS has many advantages over traditional isotope ratio mass spectrometry (IRMS), it may also be prone to errors that do not impact upon IRMS analyses. Of particular concern is the potential for contaminants in the water sample to interfere with the spectroscopy, thus leading to erroneous stable isotope data. Water extracted from plant and soil samples may often contain organic contaminants. The extent to which contaminants may interfere with IRIS and thus impact upon data quality is presently unknown. We tested the performance of IRIS relative to IRMS for water extracted from 11 plant species and one organic soil horizon. IRIS deviated considerably from IRMS for over half of the samples tested, with deviations as large as 46 per thousand (delta(2)H) and 15.4 per thousand (delta(18)O) being measured. This effect was reduced somewhat by using activated charcoal to remove organics from the water; however, deviations as large as 35 per thousand (delta(2)H) and 11.8 per thousand (delta(18)O) were still measured for these cleaned samples. Interestingly, the use of activated charcoal to clean water samples had less effect than previously thought for IRMS analyses. Our data show that extreme caution is required when using IRIS to analyse water samples that may contain organic contaminants. We suggest that the development of new cleaning techniques for removing organic contaminants together with instrument-based software to flag potentially problematic samples are necessary to ensure accurate plant and soil water analyses using IRIS. PMID:20552579

  13. UBVR{sub c} I{sub c} ANALYSIS OF THE RECENTLY DISCOVERED TOTALLY ECLIPSING EXTREME MASS RATIO BINARY V1853 ORIONIS, AND A STATISTICAL LOOK AT 25 OTHER EXTREME MASS RATIO SOLAR-TYPE CONTACT BINARIES

    SciTech Connect

    Samec, R. G.; Labadorf, C. M.; Hawkins, N. C.; Faulkner, D. R.; Van Hamme, W.

    2011-10-15

    We present precision CCD light curves, a period study, photometrically derived standard magnitudes, and a five-color simultaneous Wilson code solution of the totally eclipsing, yet shallow amplitude (A{sub v} {approx} 0.4 mag) eclipsing, binary V1853 Orionis. It is determined to be an extreme mass ratio, q = 0.20, W-type W UMa overcontact binary. From our standard star observations, we find that the variable is a late-type F spectral-type dwarf, with a secondary component of about 0.24 solar masses (stellar type M5V). Its long eclipse duration (41 minutes) as compared to its period, 0.383 days, attests to the small relative size of the secondary. Furthermore, it has reached a Roche lobe fill-out of {approx}50% of its outer critical lobe as it approaches its final stages of binary star evolution, that of a fast spinning single star. Finally, a summary of about 25 extreme mass ratio solar-type binaries is given.

  14. Effect of Parasitoid: Host Ratio and Group Size on Fitness of Spathius galinae (Hymenoptera: Braconidae): Implications for Mass-Rearing.

    PubMed

    Watt, Timothy J; Duan, Jian J; Tallamy, Douglas W; Hough-Goldstein, Judith

    2015-06-01

    Producing insect natural enemies in laboratories or insectaries for biological pest control is often expensive, and developing cost-effective rearing techniques is a goal of many biological control programs. Spathius galinae Belokobylskij and Strazenac (Hymenoptera: Braconidae), a newly described ectoparasitoid of emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), is currently being evaluated for environmental introduction in the United States to provide biological control of this invasive pest. To improve mass-rearing outcomes for S. galinae, we investigated the effects of parasitoid: host ratio and parasitoid and host group size (density) on parasitoid fitness. Our results showed that when 1 emerald ash borer larva was exposed to 1, 2, 4, or 8 female parasitoids, parasitism rate was positively associated with increasing parasitoid: host ratio, while brood size, sex ratio, and fitness estimates of progeny were not affected. When a constant 1:1 parasitoid: host ratio was used, but group size varied from 1 female parasitoid and 1 host, 5 parasitoids and 5 hosts, 10 of each, and 20 of each in same size rearing cages, parasitism rates were highest when at least 5 females were exposed to 5 host larvae. Moreover, the number of progeny produced per female parasitoid was greatest when group size was 10 parasitoids and 10 hosts. These findings demonstrate that S. galinae may be reared most efficiently in moderately high-density groups (10 parasitoids and hosts) and with a 1:1 parasitoid: host ratio. PMID:26470215

  15. Screening-level models to estimate partition ratios of organic chemicals between polymeric materials, air and water.

    PubMed

    Reppas-Chrysovitsinos, Efstathios; Sobek, Anna; MacLeod, Matthew

    2016-06-15

    Polymeric materials flowing through the technosphere are repositories of organic chemicals throughout their life cycle. Equilibrium partition ratios of organic chemicals between these materials and air (KMA) or water (KMW) are required for models of fate and transport, high-throughput exposure assessment and passive sampling. KMA and KMW have been measured for a growing number of chemical/material combinations, but significant data gaps still exist. We assembled a database of 363 KMA and 910 KMW measurements for 446 individual compounds and nearly 40 individual polymers and biopolymers, collected from 29 studies. We used the EPI Suite and ABSOLV software packages to estimate physicochemical properties of the compounds and we employed an empirical correlation based on Trouton's rule to adjust the measured KMA and KMW values to a standard reference temperature of 298 K. Then, we used a thermodynamic triangle with Henry's law constant to calculate a complete set of 1273 KMA and KMW values. Using simple linear regression, we developed a suite of single parameter linear free energy relationship (spLFER) models to estimate KMA from the EPI Suite-estimated octanol-air partition ratio (KOA) and KMW from the EPI Suite-estimated octanol-water (KOW) partition ratio. Similarly, using multiple linear regression, we developed a set of polyparameter linear free energy relationship (ppLFER) models to estimate KMA and KMW from ABSOLV-estimated Abraham solvation parameters. We explored the two LFER approaches to investigate (1) their performance in estimating partition ratios, and (2) uncertainties associated with treating all different polymers as a single "bulk" polymeric material compartment. The models we have developed are suitable for screening assessments of the tendency for organic chemicals to be emitted from materials, and for use in multimedia models of the fate of organic chemicals in the indoor environment. In screening applications we recommend that KMA and KMW be

  16. Imprint of accretion disk-induced migration on gravitational waves from extreme mass ratio inspirals.

    PubMed

    Yunes, Nicolás; Kocsis, Bence; Loeb, Abraham; Haiman, Zoltán

    2011-10-21

    We study the effects of a thin gaseous accretion disk on the inspiral of a stellar-mass black hole into a supermassive black hole. We construct a phenomenological angular momentum transport equation that reproduces known disk effects. Disk torques modify the gravitational wave phase evolution to detectable levels with LISA for reasonable disk parameters. The Fourier transform of disk-modified waveforms acquires a correction with a different frequency trend than post-Newtonian vacuum terms. Such inspirals could be used to detect accretion disks with LISA and to probe their physical parameters. PMID:22107500

  17. Fast high-precision on-line determination of hydrogen isotope ratios of water or ice by continuous-flow isotope ratio mass spectrometry.

    PubMed

    Huber, C; Leuenberger, M

    2003-01-01

    A new fast high-precision on-line technique is described for the determination of hydrogen isotope ratios of water by continuous-flow mass spectrometry. For the first time H(2)/H(2)O-equilibration using a platinum catalyst has been used in a fully continuous process. A significant reduction in the H(2)/H(2)O-equilibration time is achieved by a complete vaporization of the water and by increasing the exchange temperature to 100 degrees C. The analysis time is only approximately 5 min/sample which includes equilibration and processing. Measurement precision and accuracy are better than 1 per thousand and sample consumption is only approximately 5 microL. This new technique allows the measurement of a wide range of aqueous samples either in a semi-continuous way (discrete samples are injected one after another) or in a fully continuous way. This allows us, for the first time, to make continuous measurements of ice cores. PMID:12811755

  18. Spatial Distribution, Air-Water Fugacity Ratios and Source Apportionment of Polychlorinated Biphenyls in the Lower Great Lakes Basin.

    PubMed

    Khairy, Mohammed; Muir, Derek; Teixeira, Camilla; Lohmann, Rainer

    2015-12-01

    Polychlorinated biphenyls (PCBs) continue to be contaminants of concern across the Great Lakes. It is unclear whether current concentrations are driven by ongoing primary emissions from their original uses, or whether ambient PCBs are dominated by their environmental cycling. Freely dissolved PCBs in air and water were measured using polyethylene passive samplers across Lakes Erie and Ontario during summer and fall, 2011, to investigate their spatial distribution, determine and apportion their sources and to asses their air-water exchange gradients. Average gaseous and freely dissolved ∑29 PCB concentrations ranged from 5.0 to 160 pg/m(3) and 2.0 to 55 pg/L respectively. Gaseous concentrations were significantly correlated (R(2) = 0.80) with the urban area within a 3-20 km radius. Fugacity ratios indicated that the majority of PCBs are volatilizing from the water thus acting as a secondary source for the atmosphere. Dissolved PCBs were probably linked to PCB emissions from contaminated sites and areas of concern. Positive matrix factorization indicated that although volatilized Aroclors (gaseous PCBs) and unaltered Aroclors (dissolved PCBs) dominate in some samples, ongoing non-Aroclor sources such as paints/pigments (PCB 11) and coal/wood combustion showed significant contributions across the lower Great Lakes. Accordingly, control strategies should give further attention to PCBs emitted from current use sources. PMID:25915412

  19. Application of the maximum cumulative ratio (MCR) as a screening tool for the evaluation of mixtures in residential indoor air.

    PubMed

    De Brouwere, Katleen; Cornelis, Christa; Arvanitis, Athanasios; Brown, Terry; Crump, Derrick; Harrison, Paul; Jantunen, Matti; Price, Paul; Torfs, Rudi

    2014-05-01

    The maximum cumulative ratio (MCR) method allows the categorisation of mixtures according to whether the mixture is of concern for toxicity and if so whether this is driven by one substance or multiple substances. The aim of the present study was to explore, by application of the MCR approach, whether health risks due to indoor air pollution are dominated by one substance or are due to concurrent exposure to various substances. Analysis was undertaken on monitoring data of four European indoor studies (giving five datasets), involving 1800 records of indoor air or personal exposure. Application of the MCR methodology requires knowledge of the concentrations of chemicals in a mixture together with health-based reference values for those chemicals. For this evaluation, single substance health-based reference values (RVs) were selected through a structured review process. The MCR analysis found high variability in the proportion of samples of concern for mixture toxicity. The fraction of samples in these groups of concern varied from 2% (Flemish schools) to 77% (EXPOLIS, Basel, indoor), the variation being due not only to the variation in indoor air contaminant levels across the studies but also to other factors such as differences in number and type of substances monitored, analytical performance, and choice of RVs. However, in 4 out of the 5 datasets, a considerable proportion of cases were found where a chemical-by-chemical approach failed to identify the need for the investigation of combined risk assessment. Although the MCR methodology applied in the current study provides no consideration of commonality of endpoints, it provides a tool for discrimination between those mixtures requiring further combined risk assessment and those for which a single-substance assessment is sufficient. PMID:24565859

  20. Analyzing Nuclear Fuel Cycles from Isotopic Ratios of Waste Products Applicable to Measurement by Accelerator Mass Spectrometry

    SciTech Connect

    Biegalski, S R; Whitney, S M; Buchholz, B

    2005-08-24

    An extensive study was conducted to determine isotopic ratios of nuclides in spent fuel that may be utilized to reveal historical characteristics of a nuclear reactor cycle. This forensic information is important to determine the origin of unknown nuclear waste. The distribution of isotopes in waste products provides information about a nuclear fuel cycle, even when the isotopes of uranium and plutonium are removed through chemical processing. Several different reactor cycles of the PWR, BWR, CANDU, and LMFBR were simulated for this work with the ORIGEN-ARP and ORIGEN 2.2 codes. The spent fuel nuclide concentrations of these reactors were analyzed to find the most informative isotopic ratios indicative of irradiation cycle length and reactor design. Special focus was given to long-lived and stable fission products that would be present many years after their creation. For such nuclides, mass spectrometry analysis methods often have better detection limits than classic gamma-ray spectroscopy. The isotopic ratios {sup 151}Sm/{sup 146}Sm, {sup 149}Sm/{sup 146}Sm, and {sup 244}Cm/{sup 246}Cm were found to be good indicators of fuel cycle length and are well suited for analysis by accelerator mass spectroscopy.

  1. An interlaboratory study to test instrument performance of hydrogen dual-inlet isotope-ratio mass spectrometers

    USGS Publications Warehouse

    Brand, Willi A.; Coplen, T.B.

    2001-01-01

    An interlaboratory comparison of forty isotope-ratio mass spectrometers of different ages from several vendors has been performed to test 2H/1H performance with hydrogen gases of three different isotopic compositions. The isotope-ratio results (unsufficiently corrected for H3+ contribution to the m/z = 3 collector, uncorrected for valve leakage in the change-over valves, etc.) expressed relative to one of these three gases covered a wide range of values: -630??? to -790??? for the second gas and -368??? to -462??? for the third gas. After normalizing the isotopic abundances of these test gases (linearly adjusting the ?? values so that the gases with the lowest and highest 2H content were identical for all laboratories), the standard deviation of the 40 measurements of the intermediate gas was a remarkably low 0.85???. It is concluded that the use of scaling factors is mandatory for providing accurate internationally comparable isotope-abundance values. Linear scaling for the isotope-ratio scales of gaseous hydrogen mass spectrometers is completely adequate. ?? Springer-Verlag 2001.

  2. Method for ultra-trace cesium isotope ratio measurements from environmental samples using thermal ionization mass spectrometry

    SciTech Connect

    Snow, Mathew S.; Snyder, Darin C.; Mann, Nick R.; White, Byron M.

    2015-05-01

    135Cs/137Cs isotope ratios can provide the age, origin and history of environmental Cs contamination. Relatively high precision 135Cs/137Cs isotope ratio measurements from samples containing femtogram quantities of 137Cs are needed to accurately track contamination resuspension and redistribution following environmental 137Cs releases; however, mass spectrometric analyses of environmental samples are limited by the large quantities of ionization inhibitors and isobaric interferences which are present at relatively high concentrations in the environment. We report a new approach for Cs purification from environmental samples. An initial ammonium molybdophosphate-polyacrylonitrile (AMP-PAN) column provides a robust method for extracting Cs under a wide variety of sample matrices and mass loads. Cation exchange separations using a second AMP-PAN column result in more than two orders of magnitude greater Cs/Rb separation factors than commercially available strong cation exchangers. Coupling an AMP-PAN cation exchanging step to a microcation column (AG50W resin) enables consistent 2-4% (2σ) measurement errors for samples containing 3-6,000 fg 137Cs, representing the highest precision 135Cs/137Cs ratio measurements currently reported for soil samples at the femtogram level.

  3. Superoutburst of CR Bootis: Estimation of mass ratio of a typical AM CVn star by stage A superhumps

    NASA Astrophysics Data System (ADS)

    Isogai, Keisuke; Kato, Taichi; Ohshima, Tomohito; Kasai, Kiyoshi; Oksanen, Arto; Masumoto, Kazunari; Fukushima, Daiki; Maeda, Kazuki; Kawabata, Miho; Matsuda, Risa; Kojiguchi, Naoto; Sugiura, Yuki; Takeda, Nao; Matsumoto, Katsura; Itoh, Hiroshi; Pavlenko, Elena P.; Antonyuk, Kirill; Antonyuk, Oksana; Pit, Nikolai; Sosnovskij, Aleksei; Baklanov, Alex; Babina, Julia; Sklyanov, Aleksandr; Kiyota, Seiichiro; Hambsch, Franz-Josef; Littlefield, Colin; Maeda, Yutaka; Cook, Lewis M.; Masi, Gianluca; Dubovsky, Pavol A.; Novák, Rudolf; Dvorak, Shawn; Imada, Akira; Nogami, Daisaku

    2016-08-01

    We report on two superoutbursts of the AM CVn-type object CR Boo in 2014 April-March and 2015 May-June. A precursor outburst accompanied both of these superoutbursts. During the rising branch of the main superoutburst in 2014, we detected growing superhumps (stage A superhumps) whose period was 0.017669(24) d. Assuming that this period reflects the dynamical precession rate at the radius of the 3:1 resonance, we could estimate the mass ratio (q = M2/M1) of 0.101(4) by using the stage A superhump period and the orbital period of 0.0170290(6) d. This mass ratio is consistent with that expected from the theoretical evolutionary model of AM CVn-type objects. The detection of precursor outbursts and stage A superhumps is the second case in AM CVn-type objects. There are two interpretations of the outbursts of AM CVn-type objects. One is a dwarf nova (DN) outbursts analogy, which suggets that the outbursts are caused by thermal and tidal instabilities. Another is the VY Scl-type variation, which suggests that the outbursts are caused by the variation of the mass-transfer rate of the secondary.This detection of the superhump variations strongly supports the former interpretation.

  4. Generalization of Ryan's theorem: Probing tidal coupling with gravitational waves from nearly circular, nearly equatorial, extreme-mass-ratio inspirals

    SciTech Connect

    Li Chao; Lovelace, Geoffrey

    2008-03-15

    Extreme-mass-ratio inspirals (EMRIs) and intermediate-mass-ratio inspirals (IMRIs) - binaries in which a stellar-mass object spirals into a massive black hole or other massive, compact body - are important sources of gravitational waves for LISA and LIGO, respectively. Thorne has speculated that the waves from EMRIs and IMRIs encode, in principle, all the details of (i) the central body's spacetime geometry (metric), (ii) the tidal coupling (energy and angular momentum exchange) between the central body and orbiting object, and (iii) the evolving orbital elements. Fintan Ryan has given a first partial proof that this speculation is correct: Restricting himself to nearly circular, nearly equatorial orbits and ignoring tidal coupling, Ryan proved that the central body's metric is encoded in the waves. In this paper we generalize Ryan's theorem. Retaining Ryan's restriction to nearly circular and nearly equatorial orbits, and dropping the assumption of no tidal coupling, we prove that Thorne's conjecture is nearly fully correct: the waves encode not only the central body's metric but also the evolving orbital elements and (in a sense slightly different from Thorne's conjecture) the evolving tidal coupling.

  5. Frequency domain reduced order model of aligned-spin effective-one-body waveforms with generic mass ratios and spins

    NASA Astrophysics Data System (ADS)

    Pürrer, Michael

    2016-03-01

    I provide a frequency domain reduced order model (ROM) for the aligned-spin effective-one-body model "SEOBNRv2" for data analysis with second- and third-generation ground-based gravitational wave (GW) detectors. SEOBNRv2 models the dominant mode of the GWs emitted by the coalescence of black hole binaries. The large physical parameter space (dimensionless spins -1 ≤χi≤0.99 and symmetric mass ratios 0.01 ≤η ≤0.25 ) requires sophisticated reduced order modeling techniques, including patching in the parameter space and in frequency. I find that the time window over which the inspiral-plunge and the merger-ringdown waveform in SEOBNRv2 are connected has a discontinuous dependence on the parameters when the spin parameter χ =0.8 or the symmetric mass ratio η ˜0.083 . This discontinuity increases resolution requirements for the ROM. The ROM can be used for compact binary systems with total masses of 2 M⊙ or higher for the Advanced LIGO design sensitivity and a 10 Hz lower cutoff frequency. The ROM has a worst mismatch against SEOBNRv2 of ˜1 %, but in general mismatches are better than ˜0.1 %. The ROM is crucial for key data analysis applications for compact binaries, such as GW searches and parameter estimation carried out within the LIGO Scientific Collaboration.

  6. A low-mass-ratio and deep contact binary as the progenitor of the merger V1309 Sco

    NASA Astrophysics Data System (ADS)

    Zhu, Li-Ying; Zhao, Er-Gang; Zhou, Xiao

    2016-04-01

    Nova Sco 2008 (=V1309 Sco) is an example of a V838 Mon type eruption rather than a typical classical nova. This enigmatic object was recently shown to have resulted from the merger of two stars in a contact binary. It is the first stellar merger that was identified to be undergoing a common envelope transient. To understand the properties of its binary progenitor, the pre-outburst light curves were analyzed by using the W-D method. The photometric solution of the 2002 light curve shows that it is a deep contact binary (f = 89.5(±40.5)%) with a mass ratio of 0.094. The asymmetry of the light curve is explained by the presence of a dark spot on the more massive component. The extremely high fill-out factor suggests that the merging of the contact binary is driven by dynamical mass loss from the outer Lagrange point. However, the analysis of the 2004 light curve indicates that no solutions were obtained even at an extremely low mass ratio of q = 0.03. This suggests that the common convective envelope of the binary system disappeared and the secondary component spiraled into the envelope of the primary in 2004. Finally, the ejection of the envelope of the primary produced the outburst.

  7. HIGH FILL-OUT, EXTREME MASS RATIO OVERCONTACT BINARY SYSTEMS. X. THE NEWLY DISCOVERED BINARY XY LEONIS MINORIS

    SciTech Connect

    Qian, S.-B.; Liu, L.; Zhu, L.-Y.; He, J.-J.; Bernasconi, L. E-mail: yygcn@163.com

    2011-05-15

    The newly discovered short-period close binary star, XY LMi, has been monitored photometrically since 2006. Its light curves are typical EW-type light curves and show complete eclipses with durations of about 80 minutes. Photometric solutions were determined through an analysis of the complete B, V, R, and I light curves using the 2003 version of the Wilson-Devinney code. XY LMi is a high fill-out, extreme mass ratio overcontact binary system with a mass ratio of q = 0.148 and a fill-out factor of f = 74.1%, suggesting that it is in the late evolutionary stage of late-type tidal-locked binary stars. As observed in other overcontact binary stars, evidence for the presence of two dark spots on both components is given. Based on our 19 epochs of eclipse times, we found that the orbital period of the overcontact binary is decreasing continuously at a rate of dP/dt = -1.67 x 10{sup -7} days yr{sup -1}, which may be caused by mass transfer from the primary to the secondary and/or angular momentum loss via magnetic stellar wind. The decrease of the orbital period may result in the increase of the fill-out, and finally, it will evolve into a single rapid-rotation star when the fluid surface reaches the outer critical Roche lobe.

  8. The determination of the masses of Magellanic Cloud planetary nebulae using forbidden O II doublet ratio electron densities

    NASA Astrophysics Data System (ADS)

    Barlow, M. J.

    1987-07-01

    Spectrophotometric data, including [O II] 3726, 3729 Å doublet ratios, are presented for 32 planetary nebulae (PN) in the Magellanic Clouds. It is argued that the electron densities derived from these ratios provide a much better diagnostic for the determination of nebular masses than previously assumed. The optically thick PN are found to all have electron densities greater than 6000 cm-3, while the optically thin PN all have electron densities below 5000 cm-3. The optically thin PN show a range of only a factor of 2.0 in their derived masses, and have a mean ionized mass of 0.27±0.06 M_sun;. The absolute Hβ fluxes of the optically thick nebulae show a range of only a factor of 1.8. The application of these results to Galactic PN would yield distances which are generally larger than those previously estimated. A method of distance determination is proposed for optically thin PN that uses integrated nebular [O II] electron densities rather than angular diameters.

  9. Analytical high-order post-Newtonian expansions for extreme mass ratio binaries

    NASA Astrophysics Data System (ADS)

    Kavanagh, Chris; Ottewill, Adrian C.; Wardell, Barry

    2015-10-01

    We present analytic computations of gauge invariant quantities for a point mass in a circular orbit around a Schwarzschild black hole, giving results up to 15.5 post-Newtonian order in this paper and up to 21.5 post-Newtonian order in an online repository. Our calculation is based on the functional series method of Mano, Suzuki, and Takasugi (MST) and a recent series of results by Bini and Damour. We develop an optimized method for generating post-Newtonian expansions of the MST series, enabling significantly faster computations. We also clarify the structure of the expansions for large values of ℓ , and in doing so develop an efficient new method for generating the MST renormalized angular momentum, ν .

  10. Measurements of in-air output ratios for a linear accelerator with and without the flattening filter.

    PubMed

    Zhu, X R; Kang, Y; Gillin, M T

    2006-10-01

    The in-air output ratio (Sc) for photon beams from linear accelerators describes the change of in-air output as a function of the collimator settings. The physical origin of the Sc is mainly due to the change in scattered radiation that can reach the point of measurement as the geometry of the head changes. The flattening filter (FF) and primary collimator are the major sources of scattered radiation. The change in amount of backscattered radiation from the collimator into the beam-monitoring chamber also contributes to the variation of output. In this work, we measured the Sc and backscatter factors (Sb) into the beam-monitoring chamber for a linear accelerator with and without the FF. We measured the Sc with a Farmer-type chamber in a miniphantom at the depth of 10 g/cm2 for 6- and 18-MV x-ray beams from a Varian Clinac 2100EX linear accelerator. The Sb were measured with a universal pulse counter and a diode array with build-in counting hardware and software. The head scatter component (Sh) was then derived from the relationship Sc= Sh x Sb, where Sb was the linear fit of measured results. Significant differences were observed for Sc with and without the FF. Within the range of experimental uncertainty, the Sb was similar with and without the FF. The variations in Sh differed significantly over the range of field sizes of 3 X 3 to 40 X 40 cm2 with and without the FF; for the 6-MV beam, it was 8% vs 3%, and for the 18-MV beam, 7% vs 1%. By analyzing the contributions of backscatter factor and total in-air output ratios with and without the FF, we directly gained insight into the contributions of different components to the total variations in Sc of a linear accelerator. Sc, Sb, and Sh are basic and useful dosimetric quantities for delivery of intensity-modulated radiation therapy using a linear accelerator operating in a mode without the FF. PMID:17089838

  11. Estimation of whole lemon mass transfer parameters during hot air drying using different modelling methods

    NASA Astrophysics Data System (ADS)

    Torki-Harchegani, Mehdi; Ghanbarian, Davoud; Sadeghi, Morteza

    2015-08-01

    To design new dryers or improve existing drying equipments, accurate values of mass transfer parameters is of great importance. In this study, an experimental and theoretical investigation of drying whole lemons was carried out. The whole lemons were dried in a convective hot air dryer at different air temperatures (50, 60 and 75 °C) and a constant air velocity (1 m s-1). In theoretical consideration, three moisture transfer models including Dincer and Dost model, Bi- G correlation approach and conventional solution of Fick's second law of diffusion were used to determine moisture transfer parameters and predict dimensionless moisture content curves. The predicted results were then compared with the experimental data and the higher degree of prediction accuracy was achieved by the Dincer and Dost model.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  13. Mass transfer characteristics of bisporus mushroom ( Agaricus bisporus) slices during convective hot air drying

    NASA Astrophysics Data System (ADS)

    Ghanbarian, Davoud; Baraani Dastjerdi, Mojtaba; Torki-Harchegani, Mehdi

    2016-05-01

    An accurate understanding of moisture transfer parameters, including moisture diffusivity and moisture transfer coefficient, is essential for efficient mass transfer analysis and to design new dryers or improve existing drying equipments. The main objective of the present study was to carry out an experimental and theoretical investigation of mushroom slices drying and determine the mass transfer characteristics of the samples dried under different conditions. The mushroom slices with two thicknesses of 3 and 5 mm were dried at air temperatures of 40, 50 and 60 °C and air flow rates of 1 and 1.5 m s-1. The Dincer and Dost model was used to determine the moisture transfer parameters and predict the drying curves. It was observed that the entire drying process took place in the falling drying rate period. The obtained lag factor and Biot number indicated that the moisture transfer in the samples was controlled by both internal and external resistance. The effective moisture diffusivity and the moisture transfer coefficient increased with increasing air temperature, air flow rate and samples thickness and varied in the ranges of 6.5175 × 10-10 to 1.6726 × 10-9 m2 s-1 and 2.7715 × 10-7 to 3.5512 × 10-7 m s-1, respectively. The validation of the Dincer and Dost model indicated a good capability of the model to describe the drying curves of the mushroom slices.

  14. Aqueous reactive species induced by a surface air discharge: Heterogeneous mass transfer and liquid chemistry pathways

    NASA Astrophysics Data System (ADS)

    Liu, D. X.; Liu, Z. C.; Chen, C.; Yang, A. J.; Li, D.; Rong, M. Z.; Chen, H. L.; Kong, M. G.

    2016-04-01

    Plasma-liquid interaction is a critical area of plasma science and a knowledge bottleneck for many promising applications. In this paper, the interaction between a surface air discharge and its downstream sample of deionized water is studied with a system-level computational model, which has previously reached good agreement with experimental results. Our computational results reveal that the plasma-induced aqueous species are mainly H+, nitrate, nitrite, H2O2 and O3. In addition, various short-lived aqueous species are also induced, regardless whether they are generated in the gas phase first. The production/loss pathways for aqueous species are quantified for an air gap width ranging from 0.1 to 2 cm, of which heterogeneous mass transfer and liquid chemistry are found to play a dominant role. The short-lived reactive oxygen species (ROS) and reactive nitrogen species (RNS) are strongly coupled in liquid-phase reactions: NO3 is an important precursor for short-lived ROS, and in turn OH, O2‑ and HO2 play a crucial role for the production of short-lived RNS. Also, heterogeneous mass transfer depends strongly on the air gap width, resulting in two distinct scenarios separated by a critical air gap of 0.5 cm. The liquid chemistry is significantly different in these two scenarios.

  15. Analysis of air mass trajectories in the northern plateau of the Iberian Peninsula

    NASA Astrophysics Data System (ADS)

    Pérez, Isidro A.; Sánchez, M. Luisa; García, M. Ángeles; Pardo, Nuria

    2015-11-01

    Air masses reaching the Iberian Peninsula, which is located between two continents and two seas, have been classified. 24-h backward air trajectories were calculated each hour for three years using the METEX model at a site in the centre of the northern plateau of the Iberian Peninsula where the air flow has scarcely been investigated to date. Rather than the usual Euclidean geometry, spherical trigonometry, together with the kernel regression method, was considered to calculate trajectory distances to the site. Numerical indicators allow for an accurate description of the results. Ranges surrounding the site from E to S evidenced a restriction in the movement of the arriving flow. However, the range to the N showed only a slight effect. A noticeable seasonal contrast was observed between winter, whose distances were the greatest, and summer, which displayed the shortest distances. Trajectory clusters, initially not considered in the METEX model, were obtained with different metrics to determine the air mass pathways reaching the site. Five clusters of trajectories were selected so as to easily explain the directions and distances covered. Regional and long range transport were observed in clusters from the NE, NW and SW. The NE cluster presented an orographic deviation and local processes were limited to the SE cluster. Finally, seasonal analysis revealed singular behaviour during autumn, when local processes centred on the N-S direction.

  16. Aqueous reactive species induced by a surface air discharge: Heterogeneous mass transfer and liquid chemistry pathways.

    PubMed

    Liu, D X; Liu, Z C; Chen, C; Yang, A J; Li, D; Rong, M Z; Chen, H L; Kong, M G

    2016-01-01

    Plasma-liquid interaction is a critical area of plasma science and a knowledge bottleneck for many promising applications. In this paper, the interaction between a surface air discharge and its downstream sample of deionized water is studied with a system-level computational model, which has previously reached good agreement with experimental results. Our computational results reveal that the plasma-induced aqueous species are mainly H(+), nitrate, nitrite, H2O2 and O3. In addition, various short-lived aqueous species are also induced, regardless whether they are generated in the gas phase first. The production/loss pathways for aqueous species are quantified for an air gap width ranging from 0.1 to 2 cm, of which heterogeneous mass transfer and liquid chemistry are found to play a dominant role. The short-lived reactive oxygen species (ROS) and reactive nitrogen species (RNS) are strongly coupled in liquid-phase reactions: NO3 is an important precursor for short-lived ROS, and in turn OH, O2(-) and HO2 play a crucial role for the production of short-lived RNS. Also, heterogeneous mass transfer depends strongly on the air gap width, resulting in two distinct scenarios separated by a critical air gap of 0.5 cm. The liquid chemistry is significantly different in these two scenarios. PMID:27033381

  17. Quantifying energy and mass transfer in crop canopies: sensors for measurement of temperature and air velocity

    NASA Technical Reports Server (NTRS)

    Bugbee, B.; Monje, O.; Tanner, B.

    1996-01-01

    Here we report on the in situ performance of inexpensive, miniature sensors that have increased our ability to measure mass and energy fluxes from plant canopies in controlled environments: 1. Surface temperature. Canopy temperature measurements indicate changes in stomatal aperture and thus latent and sensible heat fluxes. Infrared transducers from two manufacturers (Exergen Corporation, Newton, MA; and Everest Interscience, Tucson, AZ, USA) have recently become available. Transducer accuracy matched that of a more expensive hand-held infrared thermometer. 2. Air velocity varies above and within plant canopies and is an important component in mass and energy transfer models. We tested commercially-available needle, heat-transfer anemometers (1 x 50 mm cylinder) that consist of a fine-wire thermocouple and a heater inside a hypodermic needle. The needle is heated and wind speed determined from the temperature rise above ambient. These sensors are particularly useful in measuring the low wind speeds found within plant canopies. 3. Accurate measurements of air temperature adjacent to plant leaves facilitates transport phenomena modeling. We quantified the effect of radiation and air velocity on temperature rise in thermocouples from 10 to 500 micrometers. At high radiation loads and low wind speeds, temperature errors were as large as 7 degrees C above air temperature.

  18. Aqueous reactive species induced by a surface air discharge: Heterogeneous mass transfer and liquid chemistry pathways

    PubMed Central

    Liu, D. X.; Liu, Z. C.; Chen, C.; Yang, A. J.; Li, D.; Rong, M. Z.; Chen, H. L.; Kong, M. G.

    2016-01-01

    Plasma-liquid interaction is a critical area of plasma science and a knowledge bottleneck for many promising applications. In this paper, the interaction between a surface air discharge and its downstream sample of deionized water is studied with a system-level computational model, which has previously reached good agreement with experimental results. Our computational results reveal that the plasma-induced aqueous species are mainly H+, nitrate, nitrite, H2O2 and O3. In addition, various short-lived aqueous species are also induced, regardless whether they are generated in the gas phase first. The production/loss pathways for aqueous species are quantified for an air gap width ranging from 0.1 to 2 cm, of which heterogeneous mass transfer and liquid chemistry are found to play a dominant role. The short-lived reactive oxygen species (ROS) and reactive nitrogen species (RNS) are strongly coupled in liquid-phase reactions: NO3 is an important precursor for short-lived ROS, and in turn OH, O2− and HO2 play a crucial role for the production of short-lived RNS. Also, heterogeneous mass transfer depends strongly on the air gap width, resulting in two distinct scenarios separated by a critical air gap of 0.5 cm. The liquid chemistry is significantly different in these two scenarios. PMID:27033381

  19. Measurement of CO{sub 2} and N{sub 2}O at nanomolar amounts using continuous-flow isotope-ratio mass spectrometry (CF-IRMS)

    SciTech Connect

    Patel, A; Downie, S.; Webster, E.; Hopkins, D.W.; Rennie, M.J.

    1994-12-01

    We are currently developing methods using Continuous Flow Isotope Ratio Mass Spectrometry (CF-IRMS) in conjunction with a thermal desorption purification unit to measure nanomolar levels of C0{sub 2} and N{sub 2}0. Samples of the pure gases diluted in He/air and transferred to septum capped Exetainers (Labco) provided a simple means to investigate the technique. We analyzed C0{sub 2} at natural abundance in the concentration range 50 to 5 nmoles and N{sub 2}0 at two concentrations between 25 and 5 nmoles. The technique was then used to measure C0{sub 2} (natural abundance and {sup 13}C-labeled) generated from the ninhydrin reaction. The results are summarized in a table; values are expressed in delta {sup 13}C notation relative to Pee Dee Belemnite. The data show that, provided care is taken to minimize or eliminate sources of contamination (air leaks, etc.), CF-IRMS coupled with a thermal desorption unit permits measurement of {sup 13}C enrichment in much smaller amounts of isolated amino acids than has been possible until now. The new methodology, including thermal desorption, should allow stable-isotope investigations on much smaller samples than are possible with other currently available techniques-while maintaining high precision.

  20. An analytical system for studying the stable isotopes of carbon monoxide using continuous flow-isotope ratio mass spectrometry (CF-IRMS)

    NASA Astrophysics Data System (ADS)

    Pathirana, S. L.; van der Veen, C.; Popa, M. E.; Röckmann, T.

    2015-02-01

    In the atmosphere, carbon monoxide (CO) is the major sink for the hydroxyl radical (OH •), has multiple anthropogenic and natural sources and considerable spatial and seasonal variability. Measurements of CO isotopic composition are useful in constraining the strengths of its individual source and sink processes and thus its global cycle. A fully automated system for δ13C and δ18O analysis has been developed to extract CO from an air sample, convert CO into carbon dioxide (CO2) using the Schütze reagent, and then determine the isotopic composition in an isotope ratio mass spectrometer (IRMS). The entire system is continuously flushed with high-purity helium (He), the carrier gas. The blank signal of the Schütze reagent is only 1-3% of the typical sample size. The repeatability is 0.1‰ for δ13C and 0.2‰ for δ18O. The peak area allows simultaneous determination of the mole fraction with an analytical repeatability of ~0.7 nmol mol-1 for 100 mL of typical ambient air (185.4 nmol mol-1 of CO). A single, automated, measurement is performed in 18 min, so multiple measurements can be combined conveniently to improve precision.

  1. Isotope-Ratio-Monitoring Liquid Chromatography Mass Spectrometry (IRM-LCMS): First Results from a Moving Wire Interface System.

    PubMed

    Brand, W A; Dobberstein, P

    1996-08-01

    Abstract A Liquid Chromatography-Combustion (LC-C) Interface, based on a moving wire technique, has been built and tested. The LC effluent is deposited onto a transport wire, which carries the sample through solvent evaporation and combustion ovens. CO(2) from the combustion step is analysed in an isotope ratio mass spectrometer. Performance of the interface was tested by loop injections of sucrose and glucose into a liquid flow of methanol/water (80/20). Accuracy and precision of δ(13)C(PDB) < 1‰ was achieved for sample concentrations > 500 ng/ul (5μl loop), sufficient for studies at natural isotope ratios. In case of (13)C tracer applications the detection limit was determined to be about 20 pg carbon tracer (on wire). PMID:22088119

  2. Rate equation model of laser induced bias in uranium isotope ratios measured by resonance ionization mass spectrometry

    SciTech Connect

    Isselhardt, B. H.; Prussin, S. G.; Savina, M. R.; Willingham, D. G.; Knight, K. B.; Hutcheon, I. D.

    2015-12-07

    Resonance Ionization Mass Spectrometry (RIMS) has been developed as a method to measure uranium isotope abundances. In this approach, RIMS is used as an element-selective ionization process between uranium atoms and potential isobars without the aid of chemical purification and separation. The use of broad bandwidth lasers with automated feedback control of wavelength was applied to the measurement of the 235U/238U ratio to decrease laser-induced isotopic fractionation. In application, isotope standards are used to identify and correct bias in measured isotope ratios, but understanding laser-induced bias from first-principles can improve the precision and accuracy of experimental measurements. A rate equation model for predicting the relative ionization probability has been developed to study the effect of variations in laser parameters on the measured isotope ratio. The model uses atomic data and empirical descriptions of laser performance to estimate the laser-induced bias expected in experimental measurements of the 235U/238U ratio. Empirical corrections are also included to account for ionization processes that are difficult to calculate from first principles with the available atomic data. As a result, development of this model has highlighted several important considerations for properly interpreting experimental results.

  3. Rate equation model of laser induced bias in uranium isotope ratios measured by resonance ionization mass spectrometry

    DOE PAGESBeta

    Isselhardt, B. H.; Prussin, S. G.; Savina, M. R.; Willingham, D. G.; Knight, K. B.; Hutcheon, I. D.

    2015-12-07

    Resonance Ionization Mass Spectrometry (RIMS) has been developed as a method to measure uranium isotope abundances. In this approach, RIMS is used as an element-selective ionization process between uranium atoms and potential isobars without the aid of chemical purification and separation. The use of broad bandwidth lasers with automated feedback control of wavelength was applied to the measurement of the 235U/238U ratio to decrease laser-induced isotopic fractionation. In application, isotope standards are used to identify and correct bias in measured isotope ratios, but understanding laser-induced bias from first-principles can improve the precision and accuracy of experimental measurements. A rate equationmore » model for predicting the relative ionization probability has been developed to study the effect of variations in laser parameters on the measured isotope ratio. The model uses atomic data and empirical descriptions of laser performance to estimate the laser-induced bias expected in experimental measurements of the 235U/238U ratio. Empirical corrections are also included to account for ionization processes that are difficult to calculate from first principles with the available atomic data. As a result, development of this model has highlighted several important considerations for properly interpreting experimental results.« less

  4. Quantifying Uranium Isotope Ratios Using Resonance Ionization Mass Spectrometry: The Influence of Laser Parameters on Relative Ionization Probability

    SciTech Connect

    Isselhardt, Brett H.

    2011-09-01

    Resonance Ionization Mass Spectrometry (RIMS) has been developed as a method to measure relative uranium isotope abundances. In this approach, RIMS is used as an element-selective ionization process to provide a distinction between uranium atoms and potential isobars without the aid of chemical purification and separation. We explore the laser parameters critical to the ionization process and their effects on the measured isotope ratio. Specifically, the use of broad bandwidth lasers with automated feedback control of wavelength was applied to the measurement of 235U/238U ratios to decrease laser-induced isotopic fractionation. By broadening the bandwidth of the first laser in a 3-color, 3-photon ionization process from a bandwidth of 1.8 GHz to about 10 GHz, the variation in sequential relative isotope abundance measurements decreased from >10% to less than 0.5%. This procedure was demonstrated for the direct interrogation of uranium oxide targets with essentially no sample preparation. A rate equation model for predicting the relative ionization probability has been developed to study the effect of variation in laser parameters on the measured isotope ratio. This work demonstrates that RIMS can be used for the robust measurement of uranium isotope ratios.

  5. Gravitational waves from extreme mass-ratio inspirals in dynamical Chern-Simons gravity

    SciTech Connect

    Pani, Paolo; Cardoso, Vitor; Gualtieri, Leonardo

    2011-05-15

    Dynamical Chern-Simons gravity is an interesting extension of general relativity, which finds its way in many different contexts, including string theory, cosmological settings, and loop quantum gravity. In this theory, the gravitational field is coupled to a scalar field by a parity-violating term, which gives rise to characteristic signatures. Here we investigate how Chern-Simons gravity would affect the quasicircular inspiralling of a small, stellar-mass object into a large nonrotating supermassive black hole, and the accompanying emission of gravitational and scalar waves. We find the relevant equations describing the perturbation induced by the small object, and we solve them through the use of Green's function techniques. Our results show that for a wide range of coupling parameters, the Chern-Simons coupling gives rise to an increase in total energy flux, which translates into a fewer number of gravitational-wave cycles over a certain bandwidth. For space-based gravitational-wave detectors such as LISA, this effect can be used to constrain the coupling parameter effectively.

  6. Isotope ratio mass spectrometry: delta13C and delta15 N analysis for tracing the origin of illicit drugs.

    PubMed

    Galimov, E M; Sevastyanov, V S; Kulbachevskaya, E V; Golyavin, A A

    2005-01-01

    Gas chromatography/combustion/mass spectrometry (GC-C-MS) and elemental analysis/mass spectrometry (EA-MS) techniques are proposed to estimate delta(13)C and delta(15)N values in heroin, morphine, cocaine and hemp leaves, for the purposes of tracing the geographical origins of seized drugs. The values of isotope ratios for pure drugs and drugs with impurities were compared. It was demonstrated that large samples (up to 3 x 10(-6) g C) were combusted completely, so that the results obtained were valid. The data are considered to be an essential supplement to a wide-scale database designed specifically for the delta(13)C and delta(15)N values of drugs. The potential forensic and academic significance of the results is discussed. PMID:15832288

  7. Revisiting the metabolism of 19-nortestosterone using isotope ratio and high resolution/high accuracy mass spectrometry.

    PubMed

    Piper, Thomas; Schänzer, Wilhelm; Thevis, Mario

    2016-09-01

    The synthetic anabolic androgenic steroid 19-nortestosterone is prohibited in sports according to the regulations of the World Anti-Doping Agency (WADA) due to its performance-enhancing effects. Today, doping controls focus predominantly on one main urinary metabolite, 19-norandrosterone glucuronide, which offers the required detection windows for an appropriate retrospectivity of sports drug testing programs. As 19-norandrosterone can also be found in urine at low concentrations originating from in situ demethylation of other abundant steroids or from endogenous production, the exogenous source of 19-norandrosterone needs to be verified, which is commonly accomplished by carbon isotope ratio analyses. The aim of this study was to re-investigate the metabolism of 19-nortestosterone in order to probe for additional diagnostic long-term metabolites, which might support the unambiguous attribution of an endo- or exogenous source of detected 19-nortestosterone metabolites. Employing a recently introduced strategy for metabolite identification, threefold deuterated 19-nortestosterone (16,16,17-(2)H3-NT) was administered to one healthy male volunteer and urine samples were collected for 20 days. Samples were prepared with established methods separating unconjugated, glucuronidated and sulfated steroids, and analytes were further purified by means of high-performance liquid chromatography before trimethylsilylation. Deuterated metabolites were identified using gas chromatograph/thermal conversion/isotope ratio mass spectrometer comprising an additional single quadrupole mass spectrometer. Additional structural information was obtained by gas chromatography/time-of-flight mass spectrometry and liquid chromatography/high resolution mass spectrometry. In general, sulfo-conjugated metabolites were excreted for a longer time period than the corresponding glucuronides. Several unexpected losses of the arguably stable isotope labels were observed and characterized, attributed to

  8. Ratio of Dietary n-6/n-3 Polyunsaturated Fatty Acids Independently Related to Muscle Mass Decline in Hemodialysis Patients

    PubMed Central

    Wong, Te-Chih; Chen, Yu-Tong; Wu, Pei-Yu; Chen, Tzen-Wen; Chen, Hsi-Hsien; Chen, Tso-Hsiao; Yang, Shwu-Huey

    2015-01-01

    Background n-3 polyunsaturated fatty acids (PUFAs) might be useful nutritional strategy for treating patients with sarcopenia. We evaluated the effect of the intake of dietary n-3 PUFAs on the skeletal muscle mass (SMM), appendicular skeletal muscle mass (ASM), and its determinants in patients receiving standard hemodialysis (HD) treatment for the management of end stage renal disease. Methods In this cross-sectional study, data of 111 HD patients were analyzed. Anthropometric and bioelectrical impedance measurements used to estimate the muscle mass were performed the day of dialysis immediately after the dialysis session. Routine laboratory and 3-day dietary data were also collected. The cutoff value of adequate intake (AI) for both n-3 PUFAs and alpha-linolenic acid (ALA) was 1.6 g/day and 1.1 g/day for men and women, respectively. Results The mean age, mean dietary n-3 PUFAs intake, ALA intake, ratio of n-6/n-3 PUFAs intake, SMM, and ASM of patients were 61.4 ± 10.4 years, 2.0 ± 1.3 g/day, 1.5 ± 1.0 g/day, 9.5 ± 6.7 g/day, 23.9 ± 5.5 kg, and 17.5 ± 4.5 kg, respectively. A higher SMM and ASM significantly observed in patients who achieved an AI of n-3 PUFAs. Similar trends appeared to be observed among those patients who achieved the AI of ALA, but the difference was not significantly, except for ASM (P = 0.047). No relevant differences in demographics, laboratory and nutritional parameters were observed, regardless of whether the patients achieved an AI of n-3 PUFAs. Multivariate analysis showed that the BMI and equilibrated Kt/V were independent determinants of the muscle mass. Moreover, the ratio of n-6/n-3 PUFAs was an independent risk determinant of reduced ASM in HD patients. Conclusion Patients with an AI of n-3 PUFAs had better total-body SMM and ASM. A higher dietary ratio of n-6/n-3 PUFAs seemed to be associated with a reduced muscle mass in HD patients. PMID:26466314

  9. Determination of the 13C/12C ratio of ethanol derived from fruit juices and maple syrup by isotope ratio mass spectrometry: collaborative study.

    PubMed

    Jamin, Eric; Martin, Frédérique; Martin, Gilles G

    2004-01-01

    A collaborative study of the carbon-13 isotope ratio mass spectrometry (13C-IRMS) method based on fermentation ethanol for detecting some sugar additions in fruit juices and maple syrup is reported. This method is complementary to the site-specific natural isotope fractionation by nuclear magnetic resonance (SNIF-NMR) method for detecting added beet sugar in the same products (AOAC Official Methods 995.17 and 2000.19), and uses the same initial steps to recover pure ethanol. The fruit juices or maple syrups are completely fermented with yeast, and the alcohol is distilled with a quantitative yield (>96%). The carbon-13 deviation (delta13C) of ethanol is then determined by IRMS. This parameter becomes less negative when exogenous sugar derived from plants exhibiting a C4 metabolism (e.g., corn or cane) is added to a juice obtained from plants exhibiting a C3 metabolism (most common fruits except pineapple) or to maple syrup. Conversely, the delta13C of ethanol becomes more negative when exogenous sugar derived from C3 plants (e.g., beet, wheat, rice) is added to pineapple products. Twelve laboratories analyzed 2 materials (orange juice and pure cane sugar) in blind duplicate and 4 sugar-adulterated materials (orange juice, maple syrup, pineapple juice, and apple juice) as Youden pairs. The precision of that method for measuring delta13C was similar to that of other methods applied to wine ethanol or extracted sugars in juices. The within-laboratory (Sr) values ranged from 0.06 to 0.16%o (r = 0.17 to 0.46 percent per thousand), and the among-laboratories (SR) values ranged from 0.17 to 0.26 percent per thousand (R = 0.49 to 0.73 percent per thousand). The Study Directors recommend that the method be adopted as First Action by AOAC INTERNATIONAL. PMID:15287660

  10. Influence of drying air parameters on mass transfer characteristics of apple slices

    NASA Astrophysics Data System (ADS)

    Beigi, Mohsen

    2015-12-01

    To efficiently design both new drying process and equipment and/or to improve the existing systems, accurate values of mass transfer characteristics are necessary. The present study aimed to investigate the influence of drying air parameters (i.e. temperature, velocity and relative humidity) on effective diffusivity and convective mass transfer coefficient of apple slices. The Dincer and Dost model was used to determine the mass transfer characteristics. The obtained Biot number indicated that the moisture transfer in the apple slices was controlled by both internal and external resistance. The effective diffusivity and mass transfer coefficient values obtained to be in the ranges of 7.13 × 10-11-7.66 × 10-10 and 1.46 × 10-7-3.39 × 10-7 m s-1, respectively and the both of them increased with increasing drying air temperature and velocity, and decreasing relative humidity. The validation of the model showed that the model predicted the experimental drying curves of the samples with a good accuracy.

  11. High-precision extreme-mass-ratio inspirals in black hole perturbation theory and post-Newtonian theory

    NASA Astrophysics Data System (ADS)

    Forseth, Erik Robert

    The recent detection of gravitational wave (GW) signal GW150914 by the Advanced LIGO experiment has inaugurated the long-anticipated era of GW astronomy. This event saw the merger of two black holes, having roughly 36 and 29 solar masses, as well as the ringdown of the resulting 62 solar mass black hole. The energy emitted in gravitational radiation was equivalent to about three solar masses. The detection underscored the importance of theoretical models for not only isolating signal from noise, but especially for the accurate estimation of source parameters. The two-body problem in Einstein's general theory has no exact solution, and so the development of these models is highly nontrivial. We present in this thesis a set of original results on the dynamics of the inspiral for a class of binary systems known as extreme-mass-ratio inspirals (EMRIs), comprised of a small compact object (generically a stellar mass black hole) in orbit about a supermassive black hole. Our work also has potential application to intermediate-mass-ratio inspirals (IMRIs). IMRIs are thought to be a potentially strong source for ground-based GW experiments such as Advanced LIGO/VIRGO. Though not generally a good source for the LIGO network, EMRIs on the other hand are well-suited for detection by proposed space-based detectors, e.g. eLISA. Our work particularly constitutes a program of developing computational tools, methods, and results for eccentric E/IMRIs, which are thought to be astrophysically important but are much more challenging to model theoretically compared with circular orbits. We begin with a brief review of relevant parts of general relativity (GR) theory, followed by overviews of two prevailing approximation formalisms in GR, black hole perturbation (BHP) theory and post-Newtonian (PN) theory. Our first original result is a high-precision computation of the first-order gravitational metric perturbation using a Lorenz gauge frequency domain procedure. Next, we present a fast

  12. SU-E-I-19: CTDI Values for All Protocols: Using the Ratio of the DLP Measured in CTDI Phantoms to the Measured Air Exposure

    SciTech Connect

    Raterman, G; Gauntt, D

    2014-06-01

    Purpose: To propose a method other than CTDI phantom measurements for routine CT dosimetry QA. This consists of taking a series of air exposure measurements and calculating a factor for converting from this exposure measurement to the protocol's associated head or body CTDI value using DLP. The data presented are the ratios of phantom DLP to air exposure ratios for different scanners, as well as error in the displayed CTDI. Methods: For each scanner, the CTDI is measured at all available tube voltages using both the head and body phantoms. Then, the exposure is measured using a pencil chamber in air at isocenter. A ratio of phantom DLP to exposure in air for a given protocol may be calculated and used for converting a simple air dose measurement to a head or body CTDI value. For our routine QA, the exposure in air for different collimations, mAs, and kVp is measured, and displayed CTDI is recorded. Therefore, the ratio calculated may convert these exposures to CTDI values that may then be compared to the displayed CTDI for a large range of acquisition parameter combinations. Results: It was found that all scanners tend to have a ratio factor that slightly increases with kVp. Also, Philips scanners appear to have less of a dependence on kVp; whereas, GE scanners have a lower ratio at lower kVp. The use of air exposure times the DLP conversion yielded CTDI values that were less than 10% different from the displayed CTDI on several scanners. Conclusion: This method may be used as a primary method for CT dosimetry QA. As a result of the ease of measurement, a dosimetry metric specific to that scanner may be calculated for a wide variety of CT protocols, which could also be used to monitor display CTDI value accuracy.

  13. Tandem mass spectrometry determined maternal cortisone to cortisol ratio and psychiatric morbidity during pregnancy-interaction with birth weight.

    PubMed

    Hellgren, Charlotte; Edvinsson, Åsa; Olivier, Jocelien D; Fornes, Romina; Stener-Victorin, Elisabet; Ubhayasekera, S J Kumari A; Skalkidou, Alkistis; Bergquist, Jonas; Sundström-Poromaa, Inger

    2016-07-01

    Maternal serum cortisol has been suggested to be influenced by psychiatric morbidity, and may also influence fetal growth. However, several studies found equal cortisol levels in depressed and healthy pregnant women. Placental 11-β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) shields the fetus from maternal cortisol by conversion to cortisone, a function that may be compromised by maternal stress. We aimed to compare the serum ratio of cortisone to cortisol, in women with and without psychiatric morbidity during pregnancy. A secondary aim was to investigate whether fetal growth, approximated by infant birth weight, was associated with the cortisone to cortisol ratio. We performed tandem mass spectrometry analysis of serum cortisol and cortisone in late pregnancy in 94 women with antenatal psychiatric morbidity and 122 controls (cohort 1). We also compared the placental gene expression of HSD11B1 and 2 in another group of 69 women with psychiatric morbidity and 47 controls (cohort 2). There were no group differences in cortisol to cortisone ratio, absolute levels of cortisone and cortisol (cohort 1), or expression of HSD11B1 or 2 (cohort 2). However, cortisone to cortisol ratio was positively associated with birth weight in women with psychiatric morbidity, also after adjustment for gestational length, fetal sex, maternal height, smoking, SSRI use, and time of blood sampling (standardized β=0.35, p<0.001), with no association in the healthy controls Thus, the maternal serum cortisone to cortisol ratio does not seem to be affected by psychiatric morbidity, but psychiatric morbidity may increase fetal exposure to cortisol or other metabolic factors influencing fetal growth. PMID:27088373

  14. The potential of LIRIC to validate the vertical profiles of the aerosol mass concentration estimated by an air quality model

    NASA Astrophysics Data System (ADS)

    Siomos, Nikolaos; Filoglou, Maria; Poupkou, Anastasia; Liora, Natalia; Dimopoulos, Spyros; Melas, Dimitris; Chaikovsky, Anatoli; Balis, Dimitris

    2015-04-01

    Vertical profiles of the aerosol mass concentration derived by a retrieval algorithm that uses combined sunphotometer and LIDAR data (LIRIC) were used in order to validate the mass concentration profiles estimated by the air quality model CAMx. LIDAR and CIMEL measurements of the Laboratory of Atmospheric Physics of the Aristotle University of Thessaloniki were used for this validation.The aerosol mass concentration profiles of the fine and coarse mode derived by CAMx were compared with the respective profiles derived by the retrieval algorithm. For the coarse mode particles, forecasts of the Saharan dust transportation model BSC-DREAM8bV2 were also taken into account. Each of the retrieval algorithm's profiles were matched to the models' profile with the best agreement within a time window of four hours before and after the central measurement. OPAC, a software than can provide optical properties of aerosol mixtures, was also employed in order to calculate the angstrom exponent and the lidar ratio values for 355nm and 532nm for each of the model's profiles aiming in a comparison with the angstrom exponent and the lidar ratio values derived by the retrieval algorithm for each measurement. The comparisons between the fine mode aerosol concentration profiles resulted in a good agreement between CAMx and the retrieval algorithm, with the vertical mean bias error never exceeding 7 μgr/m3. Concerning the aerosol coarse mode concentration profiles both CAMx and BSC-DREAM8bV2 values are severely underestimated, although, in cases of Saharan dust transportation events there is an agreement between the profiles of BSC-DREAM8bV2 model and the retrieval algorithm.

  15. Isotopic Ratio Outlier Analysis of the S. cerevisiae Metabolome Using Accurate Mass Gas Chromatography/Time-of-Flight Mass Spectrometry: A New Method for Discovery.

    PubMed

    Qiu, Yunping; Moir, Robyn; Willis, Ian; Beecher, Chris; Tsai, Yu-Hsuan; Garrett, Timothy J; Yost, Richard A; Kurland, Irwin J

    2016-03-01

    Isotopic ratio outlier analysis (IROA) is a (13)C metabolomics profiling method that eliminates sample to sample variance, discriminates against noise and artifacts, and improves identification of compounds, previously done with accurate mass liquid chromatography/mass spectrometry (LC/MS). This is the first report using IROA technology in combination with accurate mass gas chromatography/time-of-flight mass spectrometry (GC/TOF-MS), here used to examine the S. cerevisiae metabolome. S. cerevisiae was grown in YNB media, containing randomized 95% (13)C, or 5%(13)C glucose as the single carbon source, in order that the isotopomer pattern of all metabolites would mirror the labeled glucose. When these IROA experiments are combined, the abundance of the heavy isotopologues in the 5%(13)C extracts, or light isotopologues in the 95%(13)C extracts, follows the binomial distribution, showing mirrored peak pairs for the molecular ion. The mass difference between the (12)C monoisotopic and the (13)C monoisotopic equals the number of carbons in the molecules. The IROA-GC/MS protocol developed, using both chemical and electron ionization, extends the information acquired from the isotopic peak patterns for formulas generation. The process that can be formulated as an algorithm, in which the number of carbons, as well as the number of methoximations and silylations are used as search constraints. In electron impact (EI/IROA) spectra, the artifactual peaks are identified and easily removed, which has the potential to generate "clean" EI libraries. The combination of chemical ionization (CI) IROA and EI/IROA affords a metabolite identification procedure that enables the identification of coeluting metabolites, and allowed us to characterize 126 metabolites in the current study. PMID:26820234

  16. Disentangling community functional components in a litter-macrodetritivore model system reveals the predominance of the mass ratio hypothesis

    PubMed Central

    Bílá, Karolína; Moretti, Marco; Bello, Francesco; Dias, André TC; Pezzatti, Gianni B; Van Oosten, Arend Raoul; Berg, Matty P

    2014-01-01

    Recent investigations have shown that two components of community trait composition are important for key ecosystem processes: (i) the community-weighted mean trait value (CWM), related to the mass ratio hypothesis and dominant trait values in the community, and (ii) functional diversity (FD), related to the complementarity hypothesis and the divergence of trait values. However, no experiments controlling for the inherent dependence between CWM and FD have been conducted so far. We used a novel experimental framework to disentangle the unique and shared effects of CWM and FD in a leaf litter-macrodetritivore model system. We manipulated isopod assemblages varying in species number, CWM and FD of litter consumption rate to test the relative contribution of these community parameters in the decomposition process. We showed that CWM, but also the combination of CWM and FD, is a main factor controlling litter decomposition. When we tested individual biodiversity components separately, CWM of litter consumption rate showed a significant effect on decomposition, while FD and species richness alone did not. Our study demonstrated that (i) trait composition rather than species diversity drives litter decomposition, (ii) dominant trait values in the community (CWM) play a chief role in driving ecosystem processes, corroborating the mass ratio hypothesis, and (iii) trait dissimilarity can contribute in modulating the overall biodiversity effects. Future challenge is to assess whether the generality of our finding, that is, that dominant trait values (CWM) predominate over trait dissimilarity (FD), holds for other ecosystem processes, environmental conditions and different spatial and temporal scales. PMID:24634725

  17. Acculturation and changes in body mass index, waist circumference, and waist-hip ratio among Filipino Americans with hypertension.

    PubMed

    Serafica, Reimund; Angosta, Alona D

    2016-09-01

    The purpose of this research study was to examine whether level of acculturation is a predictor of body mass index, waist circumference, and waist-hip ratio in Filipino Americans with hypertension in the United States. The Filipino Americans (N = 108) were recruited from a primary care clinic in the United States. Two instruments were used to collect and operationalize the variables, specifically: (1) Socioeconomic/Demographic Questionnaire and (2) A Short Acculturation Scale for Filipino Americans. Descriptive statistics and partial least squares were used to calculate the results. The partial least square path model identified acculturation as a predictor of body mass index, wait circumference, and waist-hip ratio among Filipino Americans. The positive path coefficient (β = 0.384) was statistically significant (t = 5.92, P < .001). Health care providers need to stress the importance of the degree of acculturation when developing culturally appropriate lifestyle and health promotion interventions among immigrant patients with hypertension. PMID:27515181

  18. Innovations in Mass Spectrometry for Precise and Accurate Isotope Ratio Determination from Very Small Analyte Quantities (Invited)

    NASA Astrophysics Data System (ADS)

    Lloyd, N. S.; Bouman, C.; Horstwood, M. S.; Parrish, R. R.; Schwieters, J. B.

    2010-12-01

    This presentation describes progress in mass spectrometry for analysing very small analyte quantities, illustrated by example applications from nuclear forensics. In this challenging application, precise and accurate (‰) uranium isotope ratios are required from 1 - 2 µm diameter uranium oxide particles, which comprise less than 40 pg of uranium. Traditionally these are analysed using thermal ionisation mass spectrometry (TIMS), and more recently using secondary ionisation mass spectrometry (SIMS). Multicollector inductively-coupled plasma mass spectrometry (MC-ICP-MS) can offer higher productivity compared to these techniques, but is traditionally limited by low efficiency of analyte utilisation (sample through to ion detection). Samples can either be introduced as a solution, or sampled directly from solid using laser ablation. Large multi-isotope ratio datasets can help identify provenance and intended use of anthropogenic uranium and other nuclear materials [1]. The Thermo Scientific NEPTUNE Plus (Bremen, Germany) with ‘Jet Interface’ option offers unparalleled MC-ICP-MS sensitivity. An analyte utilisation of c. 4% has previously been reported for uranium [2]. This high-sensitivity configuration utilises a dry high-capacity (100 m3/h) interface pump, special skimmer and sampler cones and a desolvating nebuliser system. Coupled with new acquisition methodologies, this sensitivity enhancement makes possible the analysis of micro-particles and small sample volumes at higher precision levels than previously achieved. New, high-performance, full-size and compact discrete dynode secondary electron multipliers (SEM) exhibit excellent stability and linearity over a large dynamic range and can be configured to simultaneously measure all of the uranium isotopes. Options for high abundance-sensitivity filters on two ion beams are also available, e.g. for 236U and 234U. Additionally, amplifiers with high ohm (1012 - 1013) feedback resistors have been developed to

  19. Black-hole-neutron-star mergers at realistic mass ratios: Equation of state and spin orientation effects

    NASA Astrophysics Data System (ADS)

    Foucart, Francois; Deaton, M. Brett; Duez, Matthew D.; Kidder, Lawrence E.; MacDonald, Ilana; Ott, Christian D.; Pfeiffer, Harald P.; Scheel, Mark A.; Szilagyi, Bela; Teukolsky, Saul A.

    2013-04-01

    Black-hole-neutron-star mergers resulting in the disruption of the neutron star and the formation of an accretion disk and/or the ejection of unbound material are prime candidates for the joint detection of gravitational-wave and electromagnetic signals when the next generation of gravitational-wave detectors comes online. However, the disruption of the neutron star and the properties of the postmerger remnant are very sensitive to the parameters of the binary (mass ratio, black-hole spin, neutron star radius). In this paper, we study the impact of the radius of the neutron star and the alignment of the black-hole spin on black-hole-neutron-star mergers within the range of mass ratio currently deemed most likely for field binaries (MBH˜7MNS) and for black-hole spins large enough for the neutron star to disrupt (JBH/MBH2=0.9). We find that (i) In this regime, the merger is particularly sensitive to the radius of the neutron star, with remnant masses varying from 0.3MNS to 0.1MNS for changes of only 2 km in the NS radius; (ii) 0.01M⊙-0.05M⊙ of unbound material can be ejected with kinetic energy ≳1051ergs, a significant increase compared to low mass ratio, low spin binaries. This ejecta could power detectable postmerger optical and radio afterglows. (iii) Only a small fraction of the Advanced LIGO events in this parameter range have gravitational-wave signals which could offer constraints on the equation of state of the neutron star (at best ˜3% of the events for a single detector at design sensitivity). (iv) A misaligned black-hole spin works against disk formation, with less neutron-star material remaining outside of the black hole after merger, and a larger fraction of that material remaining in the tidal tail instead of the forming accretion disk. (v) Large kicks vkick≳300km/s can be given to the final black hole as a result of a precessing black-hole-neutron-star merger, when the disruption of the neutron star occurs just outside or within the innermost

  20. Theoretical study of the effect of liquid desiccant mass flow rate on the performance of a cross flow parallel-plate liquid desiccant-air dehumidifier

    NASA Astrophysics Data System (ADS)

    Mohammad, Abdulrahman Th.; Mat, Sohif Bin; Sulaiman, M. Y.; Sopian, K.; Al-abidi, Abduljalil A.

    2013-11-01

    A computer simulation using MATLAB is investigated to predict the distribution of air stream parameters (humidity ratio and temperature) as well as desiccant parameters (temperature and concentration) inside the parallel plate absorber. The present absorber consists of fourteen parallel plates with a surface area per unit volume ratio of 80 m2/m3. Calcium chloride as a liquid desiccant flows through the top of the plates to the bottom while the air flows through the gap between the plates making it a cross flow configuration. The model results show the effect of desiccant mass flow rate on the performance of the dehumidifier (moisture removal and dehumidifier effectiveness). Performance comparisons between present cross-flow dehumidifier and another experimental cross-flow dehumidifier in the literature are carried out. The simulation is expected to help in optimizing of a cross flow dehumidifier.

  1. Evaluation of the equivalence ratio of the reacting mixture using intensity ratio of chemiluminescence in laminar partially premixed CH{sub 4}-air flames

    SciTech Connect

    Jeong, Yong Ki; Jeon, Chung Hwan; Chang, Young June

    2006-07-15

    An experimental study was performed to investigate the effects of partially premixing, varying the equivalence ratios from 0.79 to 9.52, on OH*, CH* and C{sub 2}* in laminar partially premixed flames. The signals from the electronically excited states of OH*, CH* and C{sub 2}* were detected through interference filters using a photo multiplier tube, which were processed to the intensity ratios (C{sub 2}*/CH*, C{sub 2}*/OH* and CH*/OH*) to determine a correlation with the local equivalence ratios. Furthermore, the consistency between the results of the tomographic reconstruction; Abel inversion technique, image with CCD (Couple Charged Detector) camera and the local radical intensity with PMT was investigated. The results demonstrated that (1) the flames at F=<1.36 exhibited classical double flame structure, at F>=4.76, the flames exhibited non-premixed-like flame structure and the intermediate flames at 1.36ratio of CH*/OH* was nearly proportional to 1/F for the 1 dimensional results with PMT, with a correlation coefficient of 0.99 at the equivalence ratios of 0.79-9.52. These results are in good agreement with those obtained from the two dimensional results with ICCD. However, it is difficult to predict the relationships between the equivalence ratios and intensity ratios of C{sub 2}*/CH* and C{sub 2}*/OH*. (author)

  2. Analysis of molecular hydrogen absorption toward QSO B0642–5038 for a varying proton-to-electron mass ratio

    SciTech Connect

    Bagdonaite, J.; Ubachs, W.; Murphy, M. T.; Whitmore, J. B.

    2014-02-10

    Rovibronic molecular hydrogen (H{sub 2}) transitions at redshift z {sub abs} ≅ 2.659 toward the background quasar B0642–5038 are examined for a possible cosmological variation in the proton-to-electron mass ratio μ. We utilize an archival spectrum from the Very Large Telescope/Ultraviolet and Visual Echelle Spectrograph (UVES) with a signal-to-noise ratio of ∼35 per 2.5 km s{sup –1} pixel at the observed H{sub 2} wavelengths (335-410 nm). Some 111 H{sub 2} transitions in the Lyman and Werner bands have been identified in the damped Lyα system for which a kinetic gas temperature of ∼84 K and a molecular fraction log f = –2.18 ± 0.08 are determined. The H{sub 2} absorption lines are included in a comprehensive fitting method, which allows us to extract a constraint on a variation of the proton-electron mass ratio Δμ/μ from all transitions at once. We obtain Δμ/μ = (17.1 ± 4.5{sub stat} ± 3.7{sub sys}) × 10{sup –6}. However, we find evidence that this measurement has been affected by wavelength miscalibration errors recently identified in UVES. A correction based on observations of objects with solar-like spectra gives a smaller Δμ/μ value and contributes to a larger systematic uncertainty: Δμ/μ = (12.7 ± 4.5{sub stat} ± 4.2{sub sys}) × 10{sup –6}.

  3. Constraint on a Cosmological Variation in the Proton-to-electron Mass Ratio from Electronic CO Absorption

    NASA Astrophysics Data System (ADS)

    Daprà, M.; Niu, M. L.; Salumbides, E. J.; Murphy, M. T.; Ubachs, W.

    2016-08-01

    Carbon monoxide (CO) absorption in the sub-damped Lyα absorber at redshift {z}{abs}≃ 2.69 toward the background quasar SDSS J123714.60+064759.5 (J1237+0647) was investigated for the first time in order to search for a possible variation of the proton-to-electron mass ratio, μ, over a cosmological timescale. The observations were performed with the Very Large Telescope/Ultraviolet and Visual Echelle Spectrograph with a signal-to-noise ratio of 40 per 2.5 km s‑1 per pixel at ˜5000 Å. Thirteen CO vibrational bands in this absorber are detected: the {{{A}}}1{{\\Pi }} ‑ {{{X}}}1{{{Σ }}}+ (ν \\prime , 0) for ν \\prime =0{--}8, {{{B}}}1{{{Σ }}}+ ‑ {{{X}}}1{{{Σ }}}+ (0, 0), {{{C}}}1{{{Σ }}}+ ‑ {{{X}}}1{{{Σ }}}+ (0, 0), and {{{E}}}1{{\\Pi }} ‑ {{{X}}}1{{{Σ }}}+ (0, 0) singlet–singlet bands and the {d}3{{Δ }} ‑ {{{X}}}1{{{Σ }}}+ (5, 0) singlet–triplet band. An updated database including the most precise molecular inputs needed for a μ-variation analysis is presented for rotational levels J = 0–5, consisting of transition wavelengths, oscillator strengths, natural lifetime damping parameters, and sensitivity coefficients to a variation of the proton-to-electron mass ratio. A comprehensive fitting method was used to fit all the CO bands at once and an independent constraint of {{Δ }}μ /μ =(0.7+/- {1.6}{stat}+/- {0.5}{syst})× {10}-5 was derived from CO only. A combined analysis using both molecular hydrogen and CO in the same J1237+0647 absorber returned a final constraint on the relative variation of {{Δ }}μ /μ =(-5.6+/- {5.6}{stat}+/- {3.1}{syst})× {10}-6, which is consistent with no variation over a look-back time of ˜11.4 Gyr.

  4. Constraint on a Cosmological Variation in the Proton-to-electron Mass Ratio from Electronic CO Absorption

    NASA Astrophysics Data System (ADS)

    Daprà, M.; Niu, M. L.; Salumbides, E. J.; Murphy, M. T.; Ubachs, W.

    2016-08-01

    Carbon monoxide (CO) absorption in the sub-damped Lyα absorber at redshift {z}{abs}≃ 2.69 toward the background quasar SDSS J123714.60+064759.5 (J1237+0647) was investigated for the first time in order to search for a possible variation of the proton-to-electron mass ratio, μ, over a cosmological timescale. The observations were performed with the Very Large Telescope/Ultraviolet and Visual Echelle Spectrograph with a signal-to-noise ratio of 40 per 2.5 km s‑1 per pixel at ∼5000 Å. Thirteen CO vibrational bands in this absorber are detected: the {{{A}}}1{{\\Pi }} ‑ {{{X}}}1{{{Σ }}}+ (ν \\prime , 0) for ν \\prime =0{--}8, {{{B}}}1{{{Σ }}}+ ‑ {{{X}}}1{{{Σ }}}+ (0, 0), {{{C}}}1{{{Σ }}}+ ‑ {{{X}}}1{{{Σ }}}+ (0, 0), and {{{E}}}1{{\\Pi }} ‑ {{{X}}}1{{{Σ }}}+ (0, 0) singlet–singlet bands and the {d}3{{Δ }} ‑ {{{X}}}1{{{Σ }}}+ (5, 0) singlet–triplet band. An updated database including the most precise molecular inputs needed for a μ-variation analysis is presented for rotational levels J = 0–5, consisting of transition wavelengths, oscillator strengths, natural lifetime damping parameters, and sensitivity coefficients to a variation of the proton-to-electron mass ratio. A comprehensive fitting method was used to fit all the CO bands at once and an independent constraint of {{Δ }}μ /μ =(0.7+/- {1.6}{stat}+/- {0.5}{syst})× {10}-5 was derived from CO only. A combined analysis using both molecular hydrogen and CO in the same J1237+0647 absorber returned a final constraint on the relative variation of {{Δ }}μ /μ =(-5.6+/- {5.6}{stat}+/- {3.1}{syst})× {10}-6, which is consistent with no variation over a look-back time of ∼11.4 Gyr.

  5. On the origin and destination of atmospheric moisture and air mass over the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Chen, Bin; Xu, Xiang-De; Yang, Shuai; Zhang, Wei

    2012-12-01

    The Tibet Plateau (TP) is a key region that imposes profound impacts on the atmospheric water cycle and energy budget of Asia, even the global climate. In this work, we develop a climatology of origin (destination) of air mass and moisture transported to (from) the TP using a Lagrangian moisture diagnosis combined with the forward and backward atmospheric tracking schemes. The climatology is derived from 6-h particle positions based on 5-year (2005-2009) seasonal summer trajectory dataset from the Lagrangian particle dispersion model FLEXPART using NCEP/GFS data as input, where the regional model atmosphere was globally filled with particles. The results show that (1) the dominant origin of the moisture supplied to the TP is a narrow tropical-subtropical band in the extended Arabian Sea covering a long distance from the Indian subcontinent to the Southern Hemisphere. Two additional moisture sources are located in the northwestern part of TP and the Bay of Bengal and play a secondary role. This result indicates that the moisture transporting to the TP more depends on the Indian summer monsoon controlled by large-scale circulation. (2) The moisture departing from the TP can be transported rapidly to East Asia, including East China, Korea, Japan, and even East Pacific. The qualitative similarity between the regions of diagnosed moisture loss and the pattern of the observed precipitation highlights the robustness of the role of the TP on precipitation over East Asia. (3) In contrast to the moisture origin confined in the low level, the origin and fate of whole column air mass over the TP is largely controlled by a strong high-level Asian anticyclone. The results show that the TP is a crossroad of air mass where air enters mainly from the northwest and northeast and continues in two separate streams: one goes southwestwards over the Indian Ocean and the other southeastwards through western North Pacific. Both of them partly enter the trade wind zone, which manifests the

  6. Extreme-mass-ratio inspiral corrections to the angular velocity and redshift factor of a mass in circular orbit about a Kerr black hole

    NASA Astrophysics Data System (ADS)

    Shah, Abhay G.; Friedman, John L.; Keidl, Tobias S.

    2012-10-01

    This is the first of two papers on computing the self-force in a radiation gauge for a particle of mass m moving in circular, equatorial orbit about a Kerr black hole. In the extreme-mass-ratio inspiral (EMRI) framework, with mode-sum renormalization, we compute the renormalized value of the quantity H≔(1)/(2)hαβuαuβ, gauge-invariant under gauge transformations generated by a helically symmetric gauge vector; here, hαβ is the metric perturbation, uα the particle’s 4-velocity. We find the related order m correction to the particle’s angular velocity at fixed renormalized redshift (and to its redshift at fixed angular velocity), each of which can be written in terms of H. The radiative part of the metric perturbation is constructed from a Hertz potential that is extracted from the Weyl scalar by an algebraic inversion T. S. Keidl , Phys. Rev. D 82, 124012 (2010). We then write the spin-weighted spheroidal harmonics as a sum over spin-weighted spherical harmonics Yℓms and use mode-sum renormalization to find the renormalization coefficients by matching a series in L=ℓ+1/2 to the large-L behavior of the expression for H. The nonradiative parts of the perturbed metric associated with changes in mass and angular momentum are calculated in the Kerr gauge.

  7. Influence of air mass origin on aerosol properties at a remote Michigan forest site

    NASA Astrophysics Data System (ADS)

    VanReken, T. M.; Mwaniki, G. R.; Wallace, H. W.; Pressley, S. N.; Erickson, M. H.; Jobson, B. T.; Lamb, B. K.

    2015-04-01

    The northern Great Lakes region of North America is a large, relatively pristine area. To date, there has only been limited study of the atmospheric aerosol in this region. During summer 2009, a detailed characterization of the atmospheric aerosol was conducted at the University of Michigan Biological Station (UMBS) as part of the Community Atmosphere-Biosphere Interactions Experiment (CABINEX). Measurements included particle size distribution, water-soluble composition, and CCN activity. Aerosol properties were strongly dependent on the origin of the air masses reaching the site. For ∼60% of the study period, air was transported from sparsely populated regions to the northwest. During these times aerosol loadings were low, with mean number and volume concentrations of 1630 cm-3 and 1.91 μm3 cm-3, respectively. The aerosol during clean periods was dominated by organics, and exhibited low hygroscopicities (mean κ = 0.18 at s = 0.3%). When air was from more populated regions to the east and south (∼29% of the time), aerosol properties reflected a stronger anthropogenic influence, with 85% greater particle number concentrations, 2.5 times greater aerosol volume, six times more sulfate mass, and increased hygroscopicity (mean k = 0.24 at s = 0.3%). These trends are have the potential to influence forest-atmosphere interactions and should be targeted for future study.

  8. A multivariate/chemical mass balance model for air pollution in China: A hybrid methodology

    SciTech Connect

    Zelenka, M.P.

    1992-01-01

    This research explores the possibility of using a two step method of identifying and quantifying air pollution emissions in an urban environment. The procedure uses a mathematical model called Target Transformation Factor Analysis (TTFA) to estimate source profiles using ambient trace element air concentration data. A source profile is analogous to a fingerprint since it is unique to each source of air pollution. It is important to use source profiles that are measured or estimated for the specific location under study. The profiles estimated by TTFA are then employed in a Chemical Mass Balance (CMB) source apportionment analysis for the airshed. Other known sources are estimated using source signatures from the literature. Applying the TTFA and CMB models in this fashion is called receptor modeling. Generically, a receptor model is the combination of measured air pollution concentration data with a numerical technique which apportions the measured air pollution among distinct source types. The results show that TTFA can be used to provide quantitative estimates of air pollution source profiles for an urban center in China. The number of profiles for unique source types was limited for this data set since emissions from certain types of sources co-varied during each sampling day. Consequently, the CMB analyses that applied the TTFA source profiles needed to be supplemented with standard US EPA source profiles. The application of TTFA for estimating source profiles from ambient data and the subsequent use of those profiles in CMB analyses with source profiles obtained from the EPA's source library can improve the statistical quality of the source apportionment analysis. TTFA can identify source categories of airborne pollution for specific cities, as well as give quantitative data on the composition of the emissions from those source types.

  9. Transport Regimes of Air Masses Affecting the Tropospheric Composition of the Canadian and European Arctic During RACEPAC 2014 and NETCARE 2014/2015

    NASA Astrophysics Data System (ADS)

    Bozem, H.; Hoor, P. M.; Koellner, F.; Kunkel, D.; Schneider, J.; Schulz, C.; Herber, A. B.; Borrmann, S.; Wendisch, M.; Ehrlich, A.; Leaitch, W. R.; Willis, M. D.; Burkart, J.; Thomas, J. L.; Abbatt, J.

    2015-12-01

    The Arctic is warming much faster than any other place in the world and undergoes a rapid change dominated by a changing climate in this region. The impact of polluted air masses traveling to the Arctic from various remote sources significantly contributes to the observed climate change, in contrast there are additional local emission sources contributing to the level of pollutants (trace gases and aerosol). Processes affecting the emission and transport of these pollutants are not well understood and need to be further investigated. We present aircraft based trace gas measurements in the Arctic during RACEPAC (2014) and NETCARE (2014 and 2015) with the Polar 6 aircraft of Alfred Wegener Institute (AWI) covering an area from 134°W to 17°W and 68°N to 83°N. We focus on cloud, aerosol and general transport processes of polluted air masses into the high Arctic. Based on CO and CO2 measurements and kinematic 10-day back trajectories we analyze the transport regimes prevalent during spring (RACEPAC 2014 and NETCARE 2015) and summer (NETCARE 2014) in the observed region. Whereas the eastern part of the Canadian Arctic is affected by air masses with their origin in Asia, in the central and western parts of the Canadian and European Arctic air masses from North America are predominant at the time of the measurement. In general the more northern parts of the Arctic were relatively unaffected by pollution from mid-latitudes since air masses mostly travel within the polar dome, being quite isolated. Associated mixing ratios of CO and CO2 fit into the seasonal cycle observed at NOAA ground stations throughout the Arctic, but show a more mid-latitudinal characteristic at higher altitudes. The transition is remarkably sharp and allows for a chemical definition of the polar dome. At low altitudes, synoptic disturbances transport polluted air masses from mid-latitudes into regions of the polar dome. These air masses contribute to the Arctic pollution background, but also

  10. Nonlinear torque and air-to-fuel ratio control of spark ignition engines using neuro-sliding mode techniques.

    PubMed

    Huang, Ting; Javaherian, Hossein; Liu, Derong

    2011-06-01

    This paper presents a new approach for the calibration and control of spark ignition engines using a combination of neural networks and sliding mode control technique. Two parallel neural networks are utilized to realize a neuro-sliding mode control (NSLMC) for self-learning control of automotive engines. The equivalent control and the corrective control terms are the outputs of the neural networks. Instead of using error backpropagation algorithm, the network weights of equivalent control are updated using the Levenberg-Marquardt algorithm. Moreover, a new approach is utilized to update the gain of corrective control. Both modifications of the NSLMC are aimed at improving the transient performance and speed of convergence. Using the data from a test vehicle with a V8 engine, we built neural network models for the engine torque (TRQ) and the air-to-fuel ratio (AFR) dynamics and developed NSLMC controllers to achieve tracking control. The goal of TRQ control and AFR control is to track the commanded values under various operating conditions. From simulation studies, the feasibility and efficiency of the approach are illustrated. For both control problems, excellent tracking performance has been achieved. PMID:21656924

  11. An estimation of the 18O / 16O ratio of UT/LMS ozone based on artefact CO in air sampled during CARIBIC flights

    NASA Astrophysics Data System (ADS)

    Gromov, S.; Brenninkmeijer, C. A. M.

    2015-02-01

    An issue of O3-driven artefact production of O3 in the upper troposphere/lowermost stratosphere (UT/LMS) air analysed in the CARIBIC-1 project is being discussed. By confronting the CO mixing and isotope ratios obtained from different analytical instrumentation, we (i) reject natural/artificial sampling and mixing effects as possible culprits of the problem, (ii) ascertain the chemical nature and quantify the strength of the contamination, and (iii) demonstrate successful application of the isotope mass-balance calculations for inferring the isotope composition of the contamination source. The δ18O values of the latter indicate that the oxygen is very likely being inherited from O3. The δ13C values hint at reactions of trace amounts of organics with stratospheric O3 that could have yielded the artificial CO. While the exact contamination mechanism is not known, it is clear that the issue pertains only to the earlier (first) phase of the CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) project. Finally, estimated UT/LMS ozone δ18O values are lower than those observed in the stratosphere within the same temperature range, suggesting that higher pressures (240-270 hPa) imply lower isotope fractionation controlling the local δ18O(O3) value.

  12. A new laser spectrometer for measurements of the carbon isotope ratio (δ13C) of methane in air and applications to ice core studies

    NASA Astrophysics Data System (ADS)

    Lee, J. E.; Brook, E.; Dong, F.; Gupta, M.

    2012-12-01

    Methane is the second most important anthropogenic greenhouse gas contributing to global climate change, and yet its sources and sinks are still poorly understood. Isotopic ratios of methane released to the atmosphere depend on the isotopic composition of the source and fractionation by sink processes. Analysis of isotopic compositions can provide further understanding of methane source strength and location. Traditional measurements by mass spectrometry are laborious and not easily adaptable to new continuous gas extraction methodologies. Recent technological advances have reduced the amount of methane necessary for precise measurements of δ13C in methane by laser spectrometry to a practical sample size for ice core studies. We present a new laser-based analyzer for measurement of δ13C in methane that requires less than 6 μmol of CH4. Current precision is better than ±0.5‰ (1σ, 100 seconds) on dry air with [CH4]= 2ppm. The sensor is operable in either discrete or continuous sampling modes allowing for continuous measurement of gas sample exhausted from other analyzers. Detailed performance characteristics and tests will be discussed at the meeting.

  13. Effect of the relative optical air mass and the clearness index on solar erythemal UV irradiance.

    PubMed

    Moreno, J C; Serrano, M A; Cañada, J; Gurrea, G; Utrillas, M P

    2014-09-01

    This paper analyses the effects of the clearness index (Kt) and the relative optical air mass (mr) on erythemal UV irradiance (UVER). The UVER measurements were made in Valencia (Spain) from 6:00 am to 6:00 pm between June 2003 and December 2012 and (140,000 data points). Firstly, two models were used to calculate values for the erythemal ultraviolet irradiance clearness index (KtUVER) as a function of the global irradiance clearness index (Kt). Secondly, a potential regression model to measure the KtUVER as a function of the relative optical air mass was studied. The coefficients of this regression were evaluated for clear and cloudy days, as well as for days with high and low ozone levels. Thirdly, an analysis was made of the relationship between the two effects in the experimental database, with it being found that the highest degree of agreement, or the joint highest frequencies, are located in the optical mass range mr∈[1.0, 1.2] and the clearness index range of Kt∈[0.8, 1.0]. This is useful for establishing the ranges of parameters where models are more efficient. Simple equations have been tested that can provide additional information for the engineering projects concerning thermal installations. Fourthly, a high dispersion of radiation data was observed for intermediate values of the clearness for UV and UVER. PMID:24911276

  14. Calibration of Dissolved Noble Gas Mass Spectrometric Measurements by an Air-Water Equilibration System

    NASA Astrophysics Data System (ADS)

    Hillegonds, Darren; Matsumoto, Takuya; Jaklitsch, Manfred; Han, Liang-Feng; Klaus, Philipp; Wassenaar, Leonard; Aggarwal, Pradeep

    2013-04-01

    Precise measurements by mass spectrometry of dissolved noble gases (He, Ar, Ne, Kr, Xe) in water samples require careful calibration against laboratory standards with known concentrations. Currently, air pipettes are used for day-to-day calibrations, making estimation of overall analytical uncertainties for dissolved noble gas measurements in water difficult. Air equilibrated water (AEW) is often used as a matrix-equivalent laboratory standard for dissolved gases in groundwater, because of the well-known and constant fractions of noble gases in the atmosphere. AEW standards, however, are only useful if the temperature and pressure of the gas-water equilibrium can be controlled and measured precisely (i.e., to better than 0.5%); contamination and partial sample degassing must also be prevented during sampling. Here we present the details of a new custom air-water equilibration system which consists of an insulated 600 liter tank filled with deionized water, held isothermally at a precise target temperature (<0.05 °C) through the use of a heat exchanger. The temperature and total dissolved gas of the water in the tank are monitored continually, as are atmospheric pressure and air temperature in the laboratory. Different noble gas concentration standards can be reliably produced by accurately controlling the water temperature of the equilibration system. Equilibration characteristics and reproducibility of this system for production of copper tubes containing known amounts of noble gases will be presented.

  15. Community air monitoring for pesticides-part 2: multiresidue determination of pesticides in air by gas chromatography, gas chromatography-mass spectrometry, and liquid chromatography-mass spectrometry.

    PubMed

    Hengel, Matt; Lee, P

    2014-03-01

    Two multiresidue methods were developed to determine pesticides in air collected in California. Pesticides were trapped using XAD-4 resin and extracted with ethyl acetate. Based on an analytical method from the University of California Davis Trace Analytical Laboratory, pesticides were detected by analyzing the extract by gas chromatography-mass spectrometry (GC-MS) to determine chlorothalonil, chlorthal-dimethyl, cycloate, dicloran, dicofol, EPTC, ethalfluralin, iprodione, mefenoxam, metolachlor, PCNB, permethrin, pronamide, simazine, trifluralin, and vinclozolin. A GC with a flame photometric detector was used to determine chlorpyrifos, chlorpyrifos oxon, diazinon, diazinon oxon, dimethoate, dimethoate oxon, fonophos, fonophos oxon, malathion, malathion oxon, naled, and oxydemeton. Trapping efficiencies ranged from 78 to 92 % for low level (0.5 μg) and 37-104 % for high level (50 and 100 μg) recoveries. Little to no degradation of compounds occurred over 31 days; recoveries ranged from 78 to 113 %. In the California Department of Food and Agriculture (CDFA) method, pesticides were detected by analyzing the extract by GC-MS to determine chlorothalonil, chlorpyrifos, cypermethrin, dichlorvos, dicofol, endosulfan 1, endosulfan sulfate, oxyfluorfen, permethrin, propargite, and trifluralin. A liquid chromatograph coupled to a MS was used to determine azinphos-methyl, chloropyrifos oxon, DEF, diazinon, diazinon oxon, dimethoate, dimethoate oxon, diuron, EPTC, malathion, malathion oxon, metolachlor, molinate, norflurazon, oryzalin, phosmet, propanil, simazine and thiobencarb. Trapping efficiencies for compounds determined by the CDFA method ranged from 10 to 113, 22 to 114, and 56 to 132 % for 10, 5, and 2 μg spikes, respectively. Storage tests yielded 70-170 % recovery for up to 28 days. These multiresidue methods represent flexible, sensitive, accurate, and cost-effective ways to determine residues of various pesticides in ambient air. PMID:24370860

  16. Determination of the effect of transfer between vacuum and air on mass standards of platinum-iridium and stainless steel

    NASA Astrophysics Data System (ADS)

    Davidson, Stuart

    2010-08-01

    This paper reports work undertaken to assess the change in the mass values of stainless steel and platinum-iridium weights transferred between air and vacuum and to determine the repeatability of this change. Sets of kilogram transfer standards, manufactured from stainless steel and platinum-iridium and with different surface areas, were used to determine the effect of transfer between air and vacuum on the values of the mass standards. The SI unit of mass is the only unit of the seven base SI quantities which is still defined in terms of an artefact rather than by relation to a fundamental physical constant. Work is underway to identify a means of deriving the SI unit of mass from fundamental constants and at present the two principal approaches are the International Avogadro Coordination and the watt balance projects. Both of these approaches involve realizing a kilogram in vacuum and therefore the traceability from a kilogram realized in vacuum to mass standards in air is crucial to the effective dissemination of the mass scale. The work reported here characterizes the changes in mass values of standards on transfer between air and vacuum and thus will enable traceability to be established for an in-air mass scale based on a definition of the unit in vacuum.

  17. Binary black hole coalescence in the large-mass-ratio limit: The hyperboloidal layer method and waveforms at null infinity

    SciTech Connect

    Bernuzzi, Sebastiano; Nagar, Alessandro; Zenginoglu, Anil

    2011-10-15

    We compute and analyze the gravitational waveform emitted to future null infinity by a system of two black holes in the large-mass-ratio limit. We consider the transition from the quasiadiabatic inspiral to plunge, merger, and ringdown. The relative dynamics is driven by a leading order in the mass ratio, 5PN-resummed, effective-one-body (EOB), analytic-radiation reaction. To compute the waveforms, we solve the Regge-Wheeler-Zerilli equations in the time-domain on a spacelike foliation, which coincides with the standard Schwarzschild foliation in the region including the motion of the small black hole, and is globally hyperboloidal, allowing us to include future null infinity in the computational domain by compactification. This method is called the hyperboloidal layer method, and is discussed here for the first time in a study of the gravitational radiation emitted by black hole binaries. We consider binaries characterized by five mass ratios, {nu}=10{sup -2,-3,-4,-5,-6}, that are primary targets of space-based or third-generation gravitational wave detectors. We show significative phase differences between finite-radius and null-infinity waveforms. We test, in our context, the reliability of the extrapolation procedure routinely applied to numerical relativity waveforms. We present an updated calculation of the final and maximum gravitational recoil imparted to the merger remnant by the gravitational wave emission, v{sub kick}{sup end}/(c{nu}{sup 2})=0.04474{+-}0.00007 and v{sub kick}{sup max}/(c{nu}{sup 2})=0.05248{+-}0.00008. As a self-consistency test of the method, we show an excellent fractional agreement (even during the plunge) between the 5PN EOB-resummed mechanical angular momentum loss and the gravitational wave angular momentum flux computed at null infinity. New results concerning the radiation emitted from unstable circular orbits are also presented. The high accuracy waveforms computed here could be considered for the construction of template banks

  18. Application of a Multiple Hypothesis Filter to near GEO high area-to-mass ratio space objects state estimation

    NASA Astrophysics Data System (ADS)

    Kelecy, Thomas; Jah, Moriba; DeMars, Kyle

    2012-12-01

    Optical surveys have identified a class of high area-to-mass ratio (HAMR) objects in the vicinity of the Geostationary Earth Orbit (GEO) regime. The nature of these objects is not well known, though their proximity to the GEO belt implies origins from space objects (SOs) near GEO. These HAMR objects pose a collision hazard as they transit through the vicinity of active GEO satellites. Due to their high area-to-mass ratios (AMRs), ranging from 0.1 to 20 m2/kg and higher, the effective solar radiation pressure perturbs their orbits significantly. Improvements in detection sensitivity will result in large numbers of uncorrelated tracks from surveys. A Multiple Hypothesis Filter (MHF) approach to the initial state estimation and track association provides a potentially automated and efficient approach to the processing of multiple un-correlated tracks. The availability of long-term optical angles data collected for a set of near GEO HAMR objects provides the means for testing candidate estimation processes such as the MHF. A baseline orbit determination (OD) process uses an Extended Kalman Filter/Smoother to manually estimate the 6 orbital elements and the effective area-to-mass ratio (AMR) which drives the solar radiation pressure perturbations on the orbital trajectories. In addition to allowing the characterization of the long-term behavior of the AMR, this process establishes a pseudo-truth trajectory to which the MHF analysis can be compared. An Unscented Kalman Filter (UKF) is applied in the MHF estimation process to estimate the 6 orbital elements and AMR, with no a priori state assumptions, and the results are compared to the pseudo-truth results for validation. The work to be presented summarizes the UKF/MHF process and assesses state estimation performance based on selected data for selected near GEO HAMR objects having a range of AMR value and variations. The prediction accuracy is also assessed by comparing predictions derived from filter updates to

  19. Ozone Modulation/Membrane Introduction Mass Spectrometry for Analysis of Hydrocarbon Pollutants in Air

    NASA Astrophysics Data System (ADS)

    Atkinson, D. B.

    2001-12-01

    Modulation of volatile hydrocarbons in two-component mixtures is demonstrated using an ozonolysis pretreatment with membrane introduction mass spectrometry (MIMS). The MIMS technique allows selective introduction of volatile and semivolatile analytes into a mass spectrometer via processes known collectively as pervaporation [Kotiaho and Cooks, 1992]. A semipermeable polymer membrane acts as an interface between the sample (vapor or solution) and the vacuum of the mass spectrometer. This technique has been demonstrated to allow for sensitive analysis of hydrocarbons and other non-polar volatile organic compounds (VOC`s) in air samples[Cisper et al., 1995] . The methodology has the advantages of no sample pretreatment and short analysis time, which are promising for online monitoring applications but the chief disadvantage of lack of a separation step for the different analytes in a mixture. Several approaches have been investigated to overcome this problem including use of selective chemical ionization [Bier and Cooks, 1987] and multivariate calibration techniques[Ketola et al., 1999] . A new approach is reported for the quantitative measurement of VOCs in complex matrices. The method seeks to reduce the complexity of mass spectra observed in hydrocarbon mixture analysis by selective pretreatment of the analyte mixture. In the current investigation, the rapid reaction of ozone with alkenes is used, producing oxygenated compounds which are suppressed by the MIMS system. This has the effect of removing signals due to unsaturated analytes from the compound mass spectra, and comparison of the spectra before and after the ozone treatment reveals the nature of the parent compounds. In preliminary investigations, ozone reacted completely with cyclohexene from a mixture of cylohexene and cyclohexane, and with β -pinene from a mixture of toluene and β -pinene, suppressing the ion signals from the olefins. A slight attenuation of the cyclohexane and toluene in those

  20. The importance of the electrode mass ratio in a Li-ion capacitor based on activated carbon and Li4Ti5O12

    NASA Astrophysics Data System (ADS)

    Dsoke, Sonia; Fuchs, Bettina; Gucciardi, Emanuele; Wohlfahrt-Mehrens, Margret

    2015-05-01

    This study shows how the simple modulation of the cathode/anode mass ratio, in a Li-ion capacitor based on activated carbon (AC) and Li4Ti5O12 (LTO), results in a drastic increase in performance. Starting with a device balanced in the classical way (with an AC/LTO mass ratio of 4.17), the cathode/anode mass ratio has been reduced to 1.54 and then to 0.72. At a high power density, the device with a cathode/anode mass ratio of 0.72 shows the highest energy density. In fact, at 2.3 kW L-1, it delivers an energy density of 31 Wh L-1, which is almost 10 times greater than the energy obtained with a capacitor balanced with an AC/LTO ratio of 4.17 (3.68 Wh L-1). Moreover, the reduction in the cathode/anode mass ratio from 4.17 to 0.72 improves the cycling stability with a factor of 4.8 after 1000 cycles at 10C. Electrochemical impedance spectroscopy reveals that the better power performance is due to reduced diffusion and charge transfer resistances. In addition, the anode polarization is less pronounced for the system with a lower AC/LTO mass ratio, leading to a minimization in electrolyte decomposition on the anode surface and therefore limiting the increase in the electrode resistance during cycles.

  1. Accelerator Mass Spectrometric determination of radiocarbon in stratospheric CO2, retrieved from AirCore sampling.

    NASA Astrophysics Data System (ADS)

    Paul, Dipayan; Been, Henk A.; Chen, Huilin; Kivi, Rigel; Meijer, Harro A. J.

    2015-04-01

    In this decade, understanding the impact of human activities on climate is one of the key issues of discussion globally. The continuous rise in the concentration of greenhouse gases, e.g., CO2, CH4, etc. in the atmosphere, predominantly due to human activities, is alarming and requires continuous monitoring to understand the dynamics. Radiocarbon is an important atmospheric tracer and one of the many used in the understanding of the global carbon budget, which includes the greenhouse gases like CO2 and CH4. Measurement of 14C (or radiocarbon) in atmospheric CO2 generally requires collection of large air samples (few liters) from which CO2 is extracted and then the concentration of radiocarbon is determined. Currently, Accelerator Mass Spectrometry (AMS) is the most precise, reliable and widely used technique for atmospheric radiocarbon detection. However, the regular collection of air samples from troposphere and stratosphere, for example using aircraft, is prohibitively expensive. AirCore is an innovative atmospheric sampling system, developed by NOAA. It comprises of a long tube descending from a high altitude with one end open and the other closed, and has been demonstrated to be a reliable, cost-effective sampling system for high-altitude profile (up to ~ 30 km) measurements of CH4and CO2(Karion et al. 2010). In Europe, AirCore measurements are being performed on a regular basis near Sodankylä since September 2013. Here we describe the analysis of two such AirCore samples collected in July 2014, Finland, for determining the 14C concentration in stratospheric CO2. The two AirCore samples were collected on consecutive days. Each stratospheric AirCore sample was divided into six fractions, each containing ~ 35 μg CO2 (~9.5 μg C). Each fraction was separately trapped in 1 /4 inch coiled stainless steel tubing for radiocarbon measurements. The procedure for CO2 extraction from the stratospheric air samples; the sample preparation, with samples containing < 10

  2. Persistent organic contaminants in Saharan dust air masses in West Africa, Cape Verde and the eastern Caribbean

    USGS Publications Warehouse

    Garrison, Virginia H.; Majewski, Michael S.; Foreman, William T.; Genualdi, Susan A.; Mohammed, Azad; Massey Simonich, Stacy L.

    2014-01-01

    Anthropogenic semivolatile organic compounds (SOCs) that persist in the environment, bioaccumulate, are toxic at low concentrations, and undergo long-range atmospheric transport (LRT) were identified and quantified in the atmosphere of a Saharan dust source region (Mali) and during Saharan dust incursions at downwind sites in the eastern Caribbean (U.S. Virgin Islands, Trinidad and Tobago) and Cape Verde. More organochlorine and organophosphate pesticides (OCPPs), polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyl (PCB) congeners were detected in the Saharan dust region than at downwind sites. Seven of the 13 OCPPs detected occurred at all sites: chlordanes, chlorpyrifos, dacthal, dieldrin, endosulfans, hexachlorobenzene (HCB), and trifluralin. Total SOCs ranged from 1.9–126 ng/m3 (mean = 25 ± 34) at source and 0.05–0.71 ng/m3 (mean = 0.24 ± 0.18) at downwind sites during dust conditions. Most SOC concentrations were 1–3 orders of magnitude higher in source than downwind sites. A Saharan source was confirmed for sampled air masses at downwind sites based on dust particle elemental composition and rare earth ratios, atmospheric back trajectory models, and field observations. SOC concentrations were considerably below existing occupational and/or regulatory limits; however, few regulatory limits exist for these persistent organic compounds. Long-term effects of chronic exposure to low concentrations of SOCs are unknown, as are possible additive or synergistic effects of mixtures of SOCs, biologically active trace metals, and mineral dust particles transported together in Saharan dust air masses.

  3. Persistent organic contaminants in Saharan dust air masses in West Africa, Cape Verde and the eastern Caribbean.

    PubMed

    Garrison, V H; Majewski, M S; Foreman, W T; Genualdi, S A; Mohammed, A; Massey Simonich, S L

    2014-01-15

    Anthropogenic semivolatile organic compounds (SOCs) that persist in the environment, bioaccumulate, are toxic at low concentrations, and undergo long-range atmospheric transport (LRT) were identified and quantified in the atmosphere of a Saharan dust source region (Mali) and during Saharan dust incursions at downwind sites in the eastern Caribbean (U.S. Virgin Islands, Trinidad and Tobago) and Cape Verde. More organochlorine and organophosphate pesticides (OCPPs), polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyl (PCB) congeners were detected in the Saharan dust region than at downwind sites. Seven of the 13 OCPPs detected occurred at all sites: chlordanes, chlorpyrifos, dacthal, dieldrin, endosulfans, hexachlorobenzene (HCB), and trifluralin. Total SOCs ranged from 1.9-126 ng/m(3) (mean = 25 ± 34) at source and 0.05-0.71 ng/m(3) (mean = 0.24 ± 0.18) at downwind sites during dust conditions. Most SOC concentrations were 1-3 orders of magnitude higher in source than downwind sites. A Saharan source was confirmed for sampled air masses at downwind sites based on dust particle elemental composition and rare earth ratios, atmospheric back trajectory models, and field observations. SOC concentrations were considerably below existing occupational and/or regulatory limits; however, few regulatory limits exist for these persistent organic compounds. Long-term effects of chronic exposure to low concentrations of SOCs are unknown, as are possible additive or synergistic effects of mixtures of SOCs, biologically active trace metals, and mineral dust particles transported together in Saharan dust air masses. PMID:24055669

  4. Correction of mass spectrometric isotope ratio measurements for isobaric isotopologues of O2, CO, CO2, N2O and SO2.

    PubMed

    Kaiser, Jan; Röckmann, Thomas

    2008-12-01

    Gas isotope ratio mass spectrometers usually measure ion current ratios of molecules, not atoms. Often several isotopologues contribute to an ion current at a particular mass-to-charge ratio (m/z). Therefore, corrections have to be applied to derive the desired isotope ratios. These corrections are usually formulated in terms of isotope ratios (R), but this does not reflect the practice of measuring the ion current ratios of the sample relative to those of a reference material. Correspondingly, the relative ion current ratio differences (expressed as delta values) are first converted into isotopologue ratios, then into isotope ratios and finally back into elemental delta values. Here, we present a reformulation of this data reduction procedure entirely in terms of delta values and the 'absolute' isotope ratios of the reference material. This also shows that not the absolute isotope ratios of the reference material themselves, but only product and ratio combinations of them, are required for the data reduction. These combinations can be and, for carbon and oxygen have been, measured by conventional isotope ratio mass spectrometers. The frequently implied use of absolute isotope ratios measured by specially calibrated instruments is actually unnecessary. Following related work on CO2, we here derive data reduction equations for the species O2, CO, N2O and SO2. We also suggest experiments to measure the required absolute ratio combinations for N2O, SO2 and O2. As a prelude, we summarise historic and recent measurements of absolute isotope ratios in international isotope reference materials. PMID:19016255

  5. Analytical evaluation of effect of equivalence ratio inlet-air temperature and combustion pressure on performance of several possible ram-jet fuels

    NASA Technical Reports Server (NTRS)

    Tower, Leonard K; Gammon, Benson E

    1953-01-01

    The results of an analytical investigation of the theoretical air specific impulse performance and adiabatic combustion temperatures of several possible ram-jet fuels over a range of equivalence ratios, inlet-air temperatures, and combustion pressures, is presented herein. The fuels include octane-1, 50-percent-magnesium slurry, boron, pentaborane, diborane, hydrogen, carbon, and aluminum. Thermal effects from high combustion temperatures were found to effect considerably the combustion performance of all the fuels. An increase in combustion pressure was beneficial to air specific impulse at high combustion temperatures. The use of these theoretical data in engine operation and in the evaluation of experimental data is described.

  6. A thunderstorm cell-lightning activity analysis: The new concept of air mass catchment

    NASA Astrophysics Data System (ADS)

    Mona, Tamás; Horváth, Ákos; Ács, Ferenc

    2016-03-01

    Thunderstorm cell-lightning activity is discussed in terms of analysing a thunderstorm's lightning frequency-equipotential temperature relationship. Thunderstorms were tracked using Doppler radars in five-minute time steps. Lightning is assigned to the nearest thunderstorm cell, it is characterised by lightning frequency data using LINET. Equipotential temperature is not directly estimated, instead the notion of air mass catchment is introduced to represent it. It is shown in this paper that the thunderstorm cell with maximum lightning frequency in the current time step is almost always the so-called leading storm cell. The lightning frequency activity of the non-leading storm cells is not significant.

  7. Constraint on a varying proton-electron mass ratio 1.5 billion years after the big bang.

    PubMed

    Bagdonaite, J; Ubachs, W; Murphy, M T; Whitmore, J B

    2015-02-20

    A molecular hydrogen absorber at a lookback time of 12.4 billion years, corresponding to 10% of the age of the Universe today, is analyzed to put a constraint on a varying proton-electron mass ratio, μ. A high resolution spectrum of the J1443+2724 quasar, which was observed with the Very Large Telescope, is used to create an accurate model of 89 Lyman and Werner band transitions whose relative frequencies are sensitive to μ, yielding a limit on the relative deviation from the current laboratory value of Δμ/μ=(-9.5 ± 5.4(stat)± 5.3(syst))×10(-6). PMID:25763949

  8. A Stringent Limit on a Drifting Proton-to-Electron Mass Ratio from Alcohol in the Early Universe

    NASA Astrophysics Data System (ADS)

    Bagdonaite, Julija; Jansen, Paul; Henkel, Christian; Bethlem, Hendrick L.; Menten, Karl M.; Ubachs, Wim

    2013-01-01

    The standard model of physics is built on the fundamental constants of nature, but it does not provide an explanation for their values, nor require their constancy over space and time. Here we set a limit on a possible cosmological variation of the proton-to-electron mass ratio μ by comparing transitions in methanol observed in the early universe with those measured in the laboratory. From radio-astronomical observations of PKS1830-211, we deduced a constraint of ∆μ/μ = (0.0 ± 1.0) × 10-7 at redshift z = 0.89, corresponding to a look-back time of 7 billion years. This is consistent with a null result.

  9. Effect of capsid proteins to ICG mass ratio on fluorescent quantum yield of virus-resembling optical nano-materials

    NASA Astrophysics Data System (ADS)

    Gupta, Sharad; Ico, Gerardo; Matsumura, Paul; Rao, A. L. N.; Vullev, Valentine; Anvari, Bahman

    2012-03-01

    We recently reported construction of a new type of optical nano-construct composed of genome-depleted plant infecting brome mosaic virus (BMV) doped with Indocyanine green (ICG), an FDA-approved chromophore. We refer to these constructs as optical viral ghosts (OVGs) since only the capsid protein (CP) subunits of BMV remain to encapsulate ICG. To utilize OVGs as effective nano-probes in fluorescence imaging applications, their fluorescence quantum yield needs to be maximized. In this study, we investigate the effect of altering the CP to ICG mass ratio on the fluorescent quantum yield of OVGs. Results of this study provide the basis for construction of OVGs with optimal amounts of CP and ICG to yield maximal fluorescence quantum yield.

  10. A stringent limit on a drifting proton-to-electron mass ratio from alcohol in the early universe.

    PubMed

    Bagdonaite, Julija; Jansen, Paul; Henkel, Christian; Bethlem, Hendrick L; Menten, Karl M; Ubachs, Wim

    2013-01-01

    The standard model of physics is built on the fundamental constants of nature, but it does not provide an explanation for their values, nor require their constancy over space and time. Here we set a limit on a possible cosmological variation of the proton-to-electron mass ratio μ by comparing transitions in methanol observed in the early universe with those measured in the laboratory. From radio-astronomical observations of PKS1830-211, we deduced a constraint of Δμ/μ = (0.0 ± 1.0) × 10(-7) at redshift z = 0.89, corresponding to a look-back time of 7 billion years. This is consistent with a null result. PMID:23239626

  11. Solar Radiation Pressure Estimation and Analysis of a GEO Class of High Area-to-Mass Ratio Debris Objects

    NASA Technical Reports Server (NTRS)

    Kelecy, Tom; Payne, Tim; Thurston, Robin; Stansbery, Gene

    2007-01-01

    A population of deep space objects is thought to be high area-to-mass ratio (AMR) debris having origins from sources in the geosynchronous orbit (GEO) belt. The typical AMR values have been observed to range anywhere from 1's to 10's of m(sup 2)/kg, and hence, higher than average solar radiation pressure effects result in long-term migration of eccentricity (0.1-0.6) and inclination over time. However, the nature of the debris orientation-dependent dynamics also results time-varying solar radiation forces about the average which complicate the short-term orbit determination processing. The orbit determination results are presented for several of these debris objects, and highlight their unique and varied dynamic attributes. Estimation or the solar pressure dynamics over time scales suitable for resolving the shorter term dynamics improves the orbit estimation, and hence, the orbit predictions needed to conduct follow-up observations.

  12. Particle Segregation at Contact Lines of Evaporating Colloidal Drops: Influence of the Substrate Wettability and Particle Charge-Mass Ratio.

    PubMed

    Noguera-Marín, Diego; Moraila-Martínez, Carmen L; Cabrerizo-Vílchez, Miguel A; Rodríguez-Valverde, Miguel A

    2015-06-23

    Segregation of particles during capillary/convective self-assembly is interesting for self-stratification in colloidal deposits. In evaporating drops containing colloidal particles, the wettability properties of substrate and the sedimentation of particles can affect their accumulation at contact lines. In this work we studied the size segregation and discrimination of charged particles with different densities. We performed in-plane particle counting at evaporating triple lines by using fluorescence confocal microscopy. We studied separately substrates with very different wettability properties and particles with different charge-mass ratios at low ionic strength. We used binary colloidal suspensions to compare simultaneously the deposition of two different particles. The particle deposition rate strongly depends on the receding contact angle of the substrate. We further observed a singular behavior of charged polystyrene particles in binary mixtures under "salt-free" conditions explained by the "colloidal Brazil nut" effect. PMID:26000909

  13. Diode laser-based air mass flux sensor for subsonic aeropropulsion inlets.

    PubMed

    Miller, M F; Kessler, W J; Allen, M G

    1996-08-20

    An optical air mass flux sensor based on a compact, room-temperature diode laser in a fiber-coupled delivery system has been tested on a full-scale gas turbine engine. The sensor is based on simultaneous measurements of O(2) density and Doppler-shifted velocity along a line of sight across the inlet duct. Extensive tests spanning engine power levels from idle to full afterburner demonstrate accuracy and precision of the order of 1-2% of full scale in density, velocity, and mass flux. The precision-limited velocity at atmospheric pressure was as low as 40 cm/s. Multiple data-reduction procedures are quantitatively compared to suggest optimal strategies for flight sensor packages. PMID:21102916

  14. Diode laser-based air mass flux sensor for subsonic aeropropulsion inlets

    NASA Astrophysics Data System (ADS)

    Miller, Michael F.; Kessler, William J.; Allen, Mark G.

    1996-08-01

    An optical air mass flux sensor based on a compact, room-temperature diode laser in a fiber-coupled delivery system has been tested on a full-scale gas turbine engine. The sensor is based on simultaneous measurements of O 2 density and Doppler-shifted velocity along a line of sight across the inlet duct. Extensive tests spanning engine power levels from idle to full afterburner demonstrate accuracy and precision of the order of 1 2 of full scale in density, velocity, and mass flux. The precision-limited velocity at atmospheric pressure was as low as 40 cm s. Multiple data-reduction procedures are quantitatively compared to suggest optimal strategies for flight sensor packages.

  15. Uncertainty evaluation of mass values determined by electronic balances in analytical chemistry: a new method to correct for air buoyancy.

    PubMed

    Wunderli, S; Fortunato, G; Reichmuth, A; Richard, Ph

    2003-06-01

    A new method to correct for the largest systematic influence in mass determination-air buoyancy-is outlined. A full description of the most relevant influence parameters is given and the combined measurement uncertainty is evaluated according to the ISO-GUM approach [1]. A new correction method for air buoyancy using an artefact is presented. This method has the advantage that only a mass artefact is used to correct for air buoyancy. The classical approach demands the determination of the air density and therefore suitable equipment to measure at least the air temperature, the air pressure and the relative air humidity within the demanded uncertainties (i.e. three independent measurement tasks have to be performed simultaneously). The calculated uncertainty is lower for the classical method. However a field laboratory may not always be in possession of fully traceable measurement systems for these room climatic parameters.A comparison of three approaches applied to the calculation of the combined uncertainty of mass values is presented. Namely the classical determination of air buoyancy, the artefact method, and the neglecting of this systematic effect as proposed in the new EURACHEM/CITAC guide [2]. The artefact method is suitable for high-precision measurement in analytical chemistry and especially for the production of certified reference materials, reference values and analytical chemical reference materials. The method could also be used either for volume determination of solids or for air density measurement by an independent method. PMID:12732918

  16. Formic and Acetic Acid Observations over Colorado by Chemical Ionization Mass Spectrometry and Organic Acids' Role in Air Quality

    NASA Astrophysics Data System (ADS)

    Treadaway, V.; O'Sullivan, D. W.; Heikes, B.; Silwal, I.; McNeill, A.

    2015-12-01

    Formic acid (HFo) and acetic acid (HAc) have both natural and anthropogenic sources and a role in the atmospheric processing of carbon. These organic acids also have an increasing importance in setting the acidity of rain and snow as precipitation nitrate and sulfate concentrations have decreased. Primary emissions for both organic acids include biomass burning, agriculture, and motor vehicle emissions. Secondary production is also a substantial source for both acids especially from biogenic precursors, secondary organic aerosols (SOAs), and photochemical production from volatile organic compounds (VOCs) and oxygenated volatile organic compounds (OVOCs). Chemical transport models underestimate organic acid concentrations and recent research has sought to develop additional production mechanisms. Here we report HFo and HAc measurements during two campaigns over Colorado using the peroxide chemical ionization mass spectrometer (PCIMS). Iodide clusters of both HFo and HAc were recorded at mass-to-charge ratios of 173 and 187, respectively. The PCIMS was flown aboard the NCAR Gulfstream-V platform during the Deep Convective Clouds and Chemistry Experiment (DC3) and aboard the NCAR C-130 during the Front Range Air Pollution and Photochemistry Experiment (FRAPPE). The DC3 observations were made in May and June 2012 extending from the surface to 13 km over the central and eastern United States. FRAPPE observations were made in July and August 2014 from the surface to 7 km over Colorado. DC3 measurements reported here are focused over the Colorado Front Range and complement the FRAPPE observations. DC3 HFo altitude profiles are characterized by a decrease up to 6 km followed by an increase either back to boundary layer mixing ratio values or higher (a "C" shape). Organic acid measurements from both campaigns are interpreted with an emphasis on emission sources (both natural and anthropogenic) over Colorado and in situ photochemical production especially ozone precursors.

  17. Performance of human mass balance studies with stable isotope-labeled drug and continuous flow-isotope ratio mass spectrometry: a progress report.

    PubMed

    Browne, T R; Szabo, G K; Ajami, A; Browne, D G

    1998-04-01

    We propose performing human mass balance studies by administering stable isotope labeled (13C or 15N) drug and quantitating excess (above background) 13C or 15N in urine, serum, and feces by continuous flow-isotope ratio mass spectrometry (CF-IRMS). Theoretical calculations and empirical data (dynamic range, linearity, sensitivity, precision, accuracy) are presented to establish that commercially available CF-IRMS instruments can quantitate stable isotope labeled (one or two 15N or 13C labels) drug concentrations of 1.0 microg/mL or greater in urine, serum (15N), or feces. More than two 13C labels may be necessary to quantitate 1.0 microg/mL of drug in serum. Three volunteers received 650 mg of 15N13C2-acetaminophen, and urine was collected for 72 hours. Percent of administered label recovered in urine from the three subjects was 97.4, 78.9, and 95.4 for 13C and 90.3, 77.0, and 90.6 for 15N. Fecal recovery of label for one subject was 0.9% (13C2) and 1.1% (15N). Serum pharmacokinetic values obtained by counting 13C or 15N in one subject were as expected for acetaminophen. This method appears to be promising, and further validation is ongoing. PMID:9590457

  18. The impact of realistic models of mass segregation on the event rate of extreme-mass ratio inspirals and cusp re-growth

    NASA Astrophysics Data System (ADS)

    Amaro-Seoane, Pau; Preto, Miguel

    2011-05-01

    One of the most interesting sources of gravitational waves (GWs) for LISA is the inspiral of compact objects on to a massive black hole (MBH), commonly referred to as an 'extreme-mass ratio inspiral' (EMRI). The small object, typically a stellar black hole, emits significant amounts of GW along each orbit in the detector bandwidth. The slowly, adiabatic inspiral of these sources will allow us to map spacetime around MBHs in detail, as well as to test our current conception of gravitation in the strong regime. The event rate of this kind of source has been addressed many times in the literature and the numbers reported fluctuate by orders of magnitude. On the other hand, recent observations of the Galactic centre revealed a dearth of giant stars inside the inner parsec relative to the numbers theoretically expected for a fully relaxed stellar cusp. The possibility of unrelaxed nuclei (or, equivalently, with no or only a very shallow cusp, or core) adds substantial uncertainty to the estimates. Having this timely question in mind, we run a significant number of direct-summation N-body simulations with up to half a million particles to calibrate a much faster orbit-averaged Fokker-Planck code. We show that, under quite generic initial conditions, the time required for the growth of a relaxed, mass segregated stellar cusp is shorter than a Hubble time for MBHs with M• <~ 5 × 106 Modot (i.e. nuclei in the range of LISA). We then investigate the regime of strong mass segregation (SMS) for models with two different stellar mass components. Given the most recent stellar mass normalization for the inner parsec of the Galactic centre, SMS has the significant impact of boosting the EMRI rates by a factor of ~10 in comparison to what would result from a 7/4-Bahcall and Wolf cusp resulting in ~250 events per Gyr per Milky Way type galaxy. Such an intrinsic rate should translate roughly into ~102-7 × 102 sbh's (EMRIs detected by LISA over a mission lifetime of 2 or 5 years

  19. Discrimination of geographical origin of lentils (Lens culinaris Medik.) using isotope ratio mass spectrometry combined with chemometrics.

    PubMed

    Longobardi, F; Casiello, G; Cortese, M; Perini, M; Camin, F; Catucci, L; Agostiano, A

    2015-12-01

    The aim of this study was to predict the geographic origin of lentils by using isotope ratio mass spectrometry (IRMS) in combination with chemometrics. Lentil samples from two origins, i.e. Italy and Canada, were analysed obtaining the stable isotope ratios of δ(13)C, δ(15)N, δ(2)H, δ(18)O, and δ(34)S. A comparison between median values (U-test) highlighted statistically significant differences (p<0.05) for all isotopic parameters between the lentils produced in these two different geographic areas, except for δ(15)N. Applying principal component analysis, grouping of samples was observed on the basis of origin but with overlapping zones; consequently, two supervised discriminant techniques, i.e. partial least squares discriminant analysis and k-nearest neighbours algorithm were used. Both models showed good performances with external prediction abilities of about 93% demonstrating the suitability of the methods developed. Subsequently, isotopic determinations were also performed on the protein and starch fractions and the relevant results are reported. PMID:26041202

  20. Flow injection analysis-isotope ratio mass spectrometry for bulk carbon stable isotope analysis of alcoholic beverages.

    PubMed

    Jochmann, Maik A; Steinmann, Dirk; Stephan, Manuel; Schmidt, Torsten C

    2009-11-25

    A new method for bulk carbon isotope ratio determination of water-soluble samples is presented that is based on flow injection analysis-isotope ratio mass spectrometry (FIA-IRMS) using an LC IsoLink interface. Advantages of the method are that (i) only very small amounts of sample are required (2-5 microL of the sample for up to 200 possible injections), (ii) it avoids complex sample preparation procedures such as needed for EA-IRMS analysis (only sample dilution and injection,) and (iii) high throughput due to short analysis times is possible (approximately 15 min for five replicates). The method was first tested and evaluated as a fast screening method with industrially produced ethanol samples, and additionally the applicability was tested by the measurement of 81 alcoholic beverages, for example, whiskey, brandy, vodka, tequila, and others. The minimal sample concentration required for precise and reproducible measurements was around 50 microL L(-1) ethanol/water (1.71 mM carbon). The limit of repeatability was determined to be r=0.49%. FIA-IRMS represents a fast screening method for beverage authenticity control. Due to this, samples can be prescreened as a decisive criterion for more detailed investigations by HPLC-IRMS or multielement GC-IRMS measurements for a verification of adulteration. PMID:19856915

  1. Using Gas Chromatography/Isotope Ratio Mass Spectrometry to Determine the Fractionation Factor for H2 Production by Hydrogenases

    SciTech Connect

    Yang, Hui; Ghandi, H.; Shi, Liang; Kreuzer, Helen W.; Ostrom, Nathaniel; Hegg, Eric L.

    2012-01-15

    Hydrogenases catalyze the reversible formation of H2, and they are key enzymes in the biological cycling of H2. H isotopes should be a very useful tool in quantifying proton trafficking in biological H2 production processes, but there are several obstacles that have thus far limited the use of this tool. In this manuscript, we describe a new method that overcomes some of these barriers and is specifically designed to measure isotopic fractionation during enzyme-catalyzed H2 evolution. A key feature of this technique is that purified hydrogenases are employed, allowing precise control over the reaction conditions and therefore a high level of precision. A custom-designed high-throughput gas chromatography-isotope ratio mass spectrometer is employed to measure the isotope ratio of the H2. Using this method, we determined that the fractionation factor of H2 production by the [NiFe]-hydrogenase from Desulfivibrio fructosovran is 0.27. This result indicates that, as expected, protons are highly favored over deuterons during H2 evolution. Potential applications of this new method are discussed.

  2. Observation of the transport of polluted air masses from the northeastern United States to Cape Sable Island, Nova Scotia, Canada, during the 1993 NARE summer intensive

    NASA Astrophysics Data System (ADS)

    Knapp, K. G.; Balsley, B. B.; Jensen, M. L.; Hanson, H. P.; Birks, J. W.

    1998-06-01

    Vertical profiles of ozone, temperature, pressure, and water vapor mass mixing ratio obtained using a parafoil kite platform during the North Atlantic Regional Experiment (NARE) 1993 summer intensive at Cape Sable Island, Nova Scotia, Canada, demonstrate the of use of kite platforms for the collection of vertically and temporally resolved data over a fixed location. During the period August 8-28, 1993, 39 profiles of the lower atmosphere were collected. Data collected as part of this field campaign illustrate the complex vertical stratification and temporal variability of pollutants transported into the Maritime Provinces of Canada. Transport phenomena resulted in pollution events in which ozone at the ground level remained in the 20-40 parts per billion by volume (ppbv) range, while mixing ratios of 90-130 ppbv were observed above ˜300 m. Back trajectories indicate that these highly elevated levels of ozone are attributable to source regions in the heavily industrialized northeastern United States. Vertical stratification of the lower atmosphere was also present during transport of Canadian air to the sampling site, with layers of both elevated and diminished ozone observed, while marine air did not exhibit layering characteristic of air masses originating from continental source regions.

  3. Body mass index, waist-to-hip ratio, and metabolic syndrome as predictors of middle-aged men's health

    PubMed Central

    Park, Jung Hyun; Cho, In-Chang; Kim, Yoo Seok; Kim, Soon Ki; Min, Seung Ki

    2015-01-01

    Purpose There is no reported evidence for an anthropometric index that might link obesity to men's sexual health. We evaluated the ability of an anthropometric index and the symptom scores of five widely used questionnaires to detect men's health problems. We determined the predictive abilities of two obesity indexes and other clinical parameters for screening for lower urinary tract symptoms and sexual dysfunction in middle-aged men. Materials and Methods A total of 1,910 middle-aged men were included in the study. Participants underwent a detailed clinical evaluation that included recording the symptom scores of five widely used questionnaires. The participants' body mass index and waist-to-hip ratio were determined. Serum prostate-specific antigen, urinalysis, testosterone, estimated glomerular filtration rate, evaluation of metabolic syndrome, and transrectal ultrasonography were assessed. Results By use of logistic regression analysis, age and total prostate volume were independent predictors of lower urinary tract symptoms. Metabolic syndrome was the only significant negative predictive factor for chronic prostatitis symptoms. Age and metabolic syndrome were independent predictive factors for erectile dysfunction. Waist-to-hip ratio had a statistically significant value for predicting erectile dysfunction. Conclusions Our data showed that total prostate volume is a significant predictor of lower urinary tract symptoms, and central obesity has predictive ability for erectile dysfunction. Metabolic syndrome was the only significant negative predictive factor for chronic prostatitis-like symptoms. The management of correctable factors such as waist-to-hip ratio and metabolic syndrome may be considered preventive modalities against t