Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

NARCIS (Netherlands)

Moerdijk-Poortvliet, Tanja C. W.; Schierbeek, Henk; Houtekamer, Marco; van Engeland, Tom; Derrien, Delphine; Stal, Lucas J.; Boschker, Henricus T. S.

2015-01-01

We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of δ(13)C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence, although

Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

NARCIS (Netherlands)

Moerdijk-Poortvliet, T.C.W.; Schierbeek, H.; Houtekamer, M.; van Engeland, T.; Derrien, D.; Stal, L.J.; Boschker, H.T.S.

2015-01-01

We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of d13C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence, although

Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

NARCIS (Netherlands)

Moerdijk-Poortvliet, T.C.W.; Schierbeek, H.; Houtekamer, M.; van Engeland, T.; Derrien, D.; Stal, L.J.; Boschker, H.T.S.

2015-01-01

Rationale: We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of δ13C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence,

Model Persamaan Massa Karbon Akar Pohon dan Root-Shoot Ratio Massa Karbon (Equation Models of Tree Root Carbon Mass and Root-Shoot Carbon Mass Ratio

Directory of Open Access Journals (Sweden)

Elias .

2011-03-01

Full Text Available The case study was conducted in the area of Acacia mangium plantation at BKPH Parung Panjang, KPH Bogor. The objective of the study was to formulate equation models of tree root carbon mass and root to shoot carbon mass ratio of the plantation. It was found that carbon content in the parts of tree biomass (stems, branches, twigs, leaves, and roots was different, in which the highest and the lowest carbon content was in the main stem of the tree and in the leaves, respectively. The main stem and leaves of tree accounted for 70% of tree biomass. The root-shoot ratio of root biomass to tree biomass above the ground and the root-shoot ratio of root biomass to main stem biomass was 0.1443 and 0.25771, respectively, in which 75% of tree carbon mass was in the main stem and roots of tree. It was also found that the root-shoot ratio of root carbon mass to tree carbon mass above the ground and the root-shoot ratio of root carbon mass to tree main stem carbon mass was 0.1442 and 0.2034, respectively. All allometric equation models of tree root carbon mass of A. mangium have a high goodness-of-fit as indicated by its high adjusted R2.Keywords: Acacia mangium, allometric, root-shoot ratio, biomass, carbon mass

Comparison of skeletal muscle mass to fat-free mass ratios among different ethnic groups.

Science.gov (United States)

Abe, T; Bemben, M G; Kondo, M; Kawakami, Y; Fukunaga, T

2012-01-01

Asians seem to have less skeletal muscle mass (SMM) than other ethnic groups, but it is not clear whether relative SMM, i.e., SMM / height square or SMM to fat-free mass (FFM) ratio, differs among different ethnic groups at the same level of body mass index (BMI). To compare the SMM to fat-free mass (FFM) ratio as well as anthropometric variables and body composition among 3 ethnic groups. Three hundred thirty-nine Japanese, 343 Brazilian, and 183 German men and women were recruited for this cross-sectional study. Muscle thickness (MTH) and subcutaneous fat thickness (FTH) were measured by ultrasound at nine sites on the anterior and posterior aspects of the body. FTH was used to estimate the body density, from which fat mass and fat-free mass (FFM) was calculated by using Brozek equation. Total SMM was estimated from ultrasound-derived prediction equations. Percentage body fat was similar among the ethnic groups in men, while Brazilians were higher than Japanese in women. In German men and women, absolute SMM and FFM were higher than in their Japanese and Brazilians counterparts. SMM index and SMM:FFM ratios were similar among the ethnic groups in women, excluding SMM:FFM ratio in Brazilian. In men, however, these relative values (SMM index and SMM:FFM ratio) were still higher in Germans. After adjusting for age and BMI, the SMM index and SMM:FFM ratios were lower in Brazilian men and women compared with the other two ethnic groups, while the SMM index and SMM:FFM ratios were similar in Japanese and German men and women, excluding SMM:FFM ratio in women. Our results suggest that relative SMM is not lower in Asian populations compared with European populations after adjusted by age and BMI.

Dynamic Responses of Flexible Cylinders with Low Mass Ratio

Science.gov (United States)

Olaoye, Abiodun; Wang, Zhicheng; Triantafyllou, Michael

2017-11-01

Flexible cylinders with low mass ratios such as composite risers are attractive in the offshore industry because they require lower top tension and are less likely to buckle under self-weight compared to steel risers. However, their relatively low stiffness characteristics make them more vulnerable to vortex induced vibrations. Additionally, numerical investigation of the dynamic responses of such structures based on realistic conditions is limited by high Reynolds number, complex sheared flow profile, large aspect ratio and low mass ratio challenges. In the framework of Fourier spectral/hp element method, the current technique employs entropy-viscosity method (EVM) based large-eddy simulation approach for flow solver and fictitious added mass method for structure solver. The combination of both methods can handle fluid-structure interaction problems at high Reynolds number with low mass ratio. A validation of the numerical approach is provided by comparison with experiments.

Recent development in isotope ratio mass spectrometry

International Nuclear Information System (INIS)

Platzner, I.

1992-01-01

Within the limited of this review the following topics will be briefly discussed: a) Accuracy, precision, internal relative standard deviation (RISD) and external relative standard deviation (RESD) of isotope ratio measurements. With advanced instrumentation and use of standard reference materials, high accuracy and RESD = 0.002% (or better) may be achieved; b) The advantages of modern automatic isotope ratio mass spectrometer are briefly described. Computer controlled operation and data acquisition, and multiple ion collection are the recent important improvement; c) The isotopic fractionation during the course of isotope ratio measurement is considered as a major source of errors in thermal ionization of metallic elements. The phenomenon in strontium, neodymium, uranium, lead and calcium and methods to correct the measured data are discussed; d) Applications of isotope ratio mass spectrometry in atomic weight determinations, the isotope dilution technique, isotope geology, and isotope effects in biological systems are described together with specific applications in various research and technology area. (author)

The design, operation and application of a low-cost electronic device for the determination of ion-intensity ratios

International Nuclear Information System (INIS)

Lawson, A.M.; Bulmer, R.J.; Lowe, A.E.; Pickup, J.F.

1977-01-01

A low-cost electronic device to monitor two ions and provide the ratio of their intensities is described. The device operates in two modes, repetitive and accumulative. In the repetitive mode consecutive channels are integrated and their ratios displayed and printed, whereas in the accumulative mode, integrals of ion intensities are summed for a period before ratios are given. The unit has been designed principally for application in quantitative experiments using stable-isotope dilution with mass spectrometry. The precision of the ratios generated are demonstrated using hexachlorobutadiene mass ions and a calibration series of mixtures of phosphate and 18 O-labelled phosphate as internal standard

Limits on a gravitational field dependence of the proton-electron mass ratio from H2 in white dwarf stars.

Science.gov (United States)

Bagdonaite, J; Salumbides, E J; Preval, S P; Barstow, M A; Barrow, J D; Murphy, M T; Ubachs, W

2014-09-19

Spectra of molecular hydrogen (H2) are employed to search for a possible proton-to-electron mass ratio (μ) dependence on gravity. The Lyman transitions of H2, observed with the Hubble Space Telescope towards white dwarf stars that underwent a gravitational collapse, are compared to accurate laboratory spectra taking into account the high temperature conditions (T∼13 000  K) of their photospheres. We derive sensitivity coefficients Ki which define how the individual H2 transitions shift due to μ dependence. The spectrum of white dwarf star GD133 yields a Δμ/μ constraint of (-2.7±4.7stat±0.2syst)×10(-5) for a local environment of a gravitational potential ϕ∼10(4) ϕEarth, while that of G29-38 yields Δμ/μ=(-5.8±3.8stat±0.3syst)×10(-5) for a potential of 2×10(4) ϕEarth.

On the electron-ion temperature ratio established by collisionless shocks

Science.gov (United States)

Vink, Jacco; Broersen, Sjors; Bykov, Andrei; Gabici, Stefano

2015-07-01

Astrophysical shocks are often collisionless shocks, in which the changes in plasma flow and temperatures across the shock are established not through Coulomb interactions, but through electric and magnetic fields. An open question about collisionless shocks is whether electrons and ions each establish their own post-shock temperature (non-equilibration of temperatures), or whether they quickly equilibrate in the shock region. Here we provide a simple, thermodynamic, relation for the minimum electron-ion temperature ratios that should be expected as a function of Mach number. The basic assumption is that the enthalpy-flux of the electrons is conserved separately, but that all particle species should undergo the same density jump across the shock, in order for the plasma to remain charge neutral. The only form of additional electron heating that we allow for is adiabatic heating, caused by the compression of the electron gas. These assumptions result in an analytic treatment of expected electron-ion temperature ratio that agrees with observations of collisionless shocks: at low sonic Mach numbers, Ms ≲ 2, the electron-ion temperature ratio is close to unity, whereas for Mach numbers above Ms ≈ 60 the electron-ion temperature ratio asymptotically approaches a temperature ratio of Te/Ti = me/ ⟨ mi ⟩. In the intermediate Mach number range the electron-ion temperature ratio scales as Te/Ti ∝ Ms-2. In addition, we calculate the electron-ion temperature ratios under the assumption of adiabatic heating of the electrons only, which results in a higher electron-ion temperature ratio, but preserves the Te/Ti ∝ Ms-2 scaling. We also show that for magnetised shocks the electron-ion temperature ratio approaches the asymptotic value Te/Ti = me/ ⟨ mi ⟩ for lower magnetosonic Mach numbers (Mms), mainly because for a strongly magnetised shock the sonic Mach number is larger than the magnetosonic Mach number (Mms ≤ Ms). The predicted scaling of the electron

Mass-to-light ratios of nearby groups of galaxies

CERN Document Server

Materne, J

1980-01-01

The application of a probability density function gives the possibility of determining groups of galaxies and membership probabilities of the galaxies in a reliable unbiased way. For the five nearest groups so defined, the mean mass-to-light ratio was derived using the concept of negative energy. These groups have a mass-to- light ratio of 16 M/sub (.)//L/sub (.)/. The probability function gives also the possibility of deriving masses of groups in a direct and independent way. (22 refs).

Relations between stellar mass and electron temperature-based metallicity for star-forming galaxies in a wide mass range

International Nuclear Information System (INIS)

Shi Wei-Bin; Zhao Gang; Ruan Gui-Ping; Zhou Li; Liang Yan-Chun; Shao Xu; Liu Xiao-Wei; Hammer Francois; Flores Hector; Zhang Yong

2014-01-01

We select 947 star-forming galaxies from SDSS-DR7 with [O III]λ4363 emission lines detected at a signal-to-noise ratio larger than 5σ. Their electron temperatures and direct oxygen abundances are then determined. We compare the results from different methods. t 2 , the electron temperature in the low ionization region, estimated from t 3 , that in the high ionization region, is compared using three analysis relations between t 2 – t 3 . These show obvious differences, which result in some different ionic oxygen abundances. The results of t 3 , t 2 , O ++ /H + and O + /H + derived by using methods from IRAF and literature are also compared. The ionic abundances O ++ /H + are higher than O + /H + for most cases. The different oxygen abundances derived from T e and the strong-line ratios show a clear discrepancy, which is more obvious following increasing stellar mass and strong-line ratio R 23 . The sample of galaxies from SDSS with detected [O III]λ4363 have lower metallicites and higher star formation rates, so they may not be typical representatives of the whole population of galaxies. Adopting data objects from Andrews and Martini, Liang et al. and Lee et al. data, we derive new relations of stellar mass and metallicity for star-forming galaxies in a much wider stellar mass range: from 10 6 M ⊙ to 10 11 M ⊙ . (research papers)

THE BLACK HOLE MASS, STELLAR MASS-TO-LIGHT RATIO, AND DARK HALO IN M87

International Nuclear Information System (INIS)

Gebhardt, Karl; Thomas, Jens

2009-01-01

We model the dynamical structure of M87 (NGC4486) using high spatial resolution long-slit observations of stellar light in the central regions, two-dimensional stellar light kinematics out to half of the effective radius, and globular cluster velocities out to eight effective radii. We simultaneously fit for four parameters: black hole mass, dark halo core radius, dark halo circular velocity, and stellar mass-to-light (M/L) ratio. We find a black hole mass of 6.4(±0.5) x 10 9 M sun (the uncertainty is 68% confidence marginalized over the other parameters). The stellar M/L V = 6.3 ± 0.8. The best-fit dark halo core radius is 14 ± 2 kpc, assuming a cored logarithmic potential. The best-fit dark halo circular velocity is 715 ± 15 km s -1 . Our black hole mass is over a factor of 2 larger than previous stellar dynamical measures, and our derived stellar M/L ratio is two times lower than previous dynamical measures. When we do not include a dark halo, we measure a black hole mass and stellar M/L ratio that is consistent with previous measures, implying that the major difference is in the model assumptions. The stellar M/L ratio from our models is very similar to that derived from stellar population models of M87. The reason for the difference in the black hole mass is because we allow the M/L ratio to change with radius. The dark halo is degenerate with the stellar M/L ratio, which is subsequently degenerate with the black hole mass. We argue that dynamical models of galaxies that do not include the contribution from a dark halo may produce a biased result for the black hole mass. This bias is especially large for a galaxy with a shallow light profile such as M87, and may not be as severe in galaxies with steeper light profiles unless they have a large stellar population change with radius.

Anomalous phosphine sensitivity coefficients as probes for a possible variation of the proton-to-electron mass ratio

Science.gov (United States)

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

2018-02-01

A robust variational approach is used to investigate the sensitivity of the rotation-vibration spectrum of phosphine (PH3) to a possible cosmological variation of the proton-to-electron mass ratio, μ. Whilst the majority of computed sensitivity coefficients, T, involving the low-lying vibrational states acquire the expected values of T ≈ -1 and T ≈ -1/2 for rotational and ro-vibrational transitions, respectively, anomalous sensitivities are uncovered for the A1 - A2 splittings in the ν2/ν4, ν1/ν3 and 2ν _4^{ℓ=0}/2ν _4^{ℓ=2} manifolds of PH3. A pronounced Coriolis interaction between these states in conjunction with accidentally degenerate A1 and A2 energy levels produces a series of enhanced sensitivity coefficients. Phosphine is expected to occur in a number of different astrophysical environments and has potential for investigating a drifting constant. Furthermore, the displayed behaviour hints at a wider trend in molecules of C_{3v}(M) symmetry, thus demonstrating that the splittings induced by higher-order ro-vibrational interactions are well suited for probing μ in other symmetric top molecules in space, since these low-frequency transitions can be straightforwardly detected by radio telescopes.

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

Energy Technology Data Exchange (ETDEWEB)

Han, C.; Jung, Y. K. [Department of Physics, Chungbuk National University, Cheongju 371-763 (Korea, Republic of); Udalski, A.; Szymański, M. K.; Kubiak, M.; Pietrzyński, G.; Soszyński, I.; Skowron, J.; Kozłowski, S.; Poleski, R.; Ulaczyk, K.; Wyrzykowski, Ł.; Pietrukowicz, P. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Sumi, T. [Department of Earth and Space Science, Osaka University, Osaka 560-0043 (Japan); Gaudi, B. S.; Gould, A. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Bennett, D. P. [University of Notre Dame, Department of Physics, 225 Nieuwland Science Hall, Notre Dame, IN 46556-5670 (United States); Tsapras, Y. [Las Cumbres Observatory Global Telescope Network, 6740B Cortona Dr, Goleta, CA 93117 (United States); Abe, F. [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601 (Japan); Bond, I. A. [Institute of Information and Mathematical Sciences, Massey University, Private Bag 102-904, North Shore Mail Centre, Auckland (New Zealand); 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.

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

International Nuclear Information System (INIS)

Doherty, W.

2015-01-01

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

Physical Parameters of Late Type Spiral Galaxies - III. Mass and Mass to Luminosity Ratio of NGC 7793

Directory of Open Access Journals (Sweden)

Chang-Ha Kim

1986-12-01

Full Text Available The mass distribution and other related quantities were calculated by fitting the observed rotation curve(Davoust and de Vaucouleur 1980 to Brandt and Belton's mass distribution model. One of n values for mass model is determined as 1.5(Vm = 95 km/s and two pairs of them are determined as 0.8(Vm = 95 km/s and 2.0 and 0.8(Vm = 55 km/s and 2.0 because f the hump in observed rotation curve. Total masses and integrated mass to luminosity ratios are 1.8 x 10^10*Msolar, 1.5 x 10^10*Msolar, 1.4 x 10^10*Msolar, and 6.57, 5.33, 5.26 for three cases according to n values. Integrated mass to luminosity ratio in Holmberg radius is 3.44, 3.26, 3.00 in good agreement with the typical value of Sd type suggested by Faber and Gallagher(1979. Presented halo masses which are fifty percent of total masses and halo mass to luminosity ratios given as 75.83, 53.50, 58.75 are values less than Turner's(1976.

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

Science.gov (United States)

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.

Determination of the mass-ratio distribution, I: single-lined spectroscopic binary stars

NARCIS (Netherlands)

Hogeveen, S.J.

1992-01-01

For single-lined spectroscopic binary stars (sbi), the mass ratio q = Msec=Mprim is calculated from the mass function f(m), which is determined from observations. For statistical investigations of the mass-ratio distribution, the term sin^3 i, that remains in the cubic equation from which q is

GUT Scale Fermion Mass Ratios

International Nuclear Information System (INIS)

Spinrath, Martin

2014-01-01

We present a series of recent works related to group theoretical factors from GUT symmetry breaking which lead to predictions for the ratios of quark and lepton Yukawa couplings at the unification scale. New predictions for the GUT scale ratios y μ /y s , y τ /y b and y t /y b in particular are shown and compared to experimental data. For this comparison it is important to include possibly large supersymmetric threshold corrections. Due to this reason the structure of the fermion masses at the GUT scale depends on TeV scale physics and makes GUT scale physics testable at the LHC. We also discuss how this new predictions might lead to predictions for mixing angles by discussing the example of the recently measured last missing leptonic mixing angle θ 13 making this new class of GUT models also testable in neutrino experiments

Galaxy Mergers and Dark Matter Halo Mergers in LCDM: Mass, Redshift, and Mass-Ratio Dependence

International Nuclear Information System (INIS)

Stewart, K.

2009-01-01

We employ a high-resolution LCDM N-body simulation to present merger rate predictions for dark matter halos and investigate how common merger-related observables for galaxies - such as close pair counts, starburst counts, and the morphologically disturbed fraction - likely scale with luminosity, stellar mass, merger mass ratio, and redshift from z = 0 to z = 4. We provide a simple 'universal' fitting formula that describes our derived merger rates for dark matter halos a function of dark halo mass, merger mass ratio, and redshift, and go on to predict galaxy merger rates using number density-matching to associate halos with galaxies. For example, we find that the instantaneous merger rate of m/M > 0.3 mass ratio events into typical L ∼> fL * galaxies follows the simple relation dN/dt ≅ 0.03(1+f)Gyr -1 (1+z) 2.1 . Despite the rapid increase in merger rate with redshift, only a small fraction of > 0.4L * high-redshift galaxies (∼ 3% at z = 2) should have experienced a major merger (m/M > 0.3) in the very recent past (t 0.3) in the last 700 Myr and conclude that mergers almost certainly play an important role in delivering baryons and influencing the kinematic properties of Lyman Break Galaxies (LBGs)

Extreme mass ratio inspiral rates: dependence on the massive black hole mass

International Nuclear Information System (INIS)

Hopman, Clovis

2009-01-01

We study the rate at which stars spiral into a massive black hole (MBH) due to the emission of gravitational waves (GWs), as a function of the mass M . of the MBH. In the context of our model, it is shown analytically that the rate approximately depends on the MBH mass as M -1/4 . . Numerical simulations confirm this result, and show that for all MBH masses, the event rate is highest for stellar black holes, followed by white dwarfs, and lowest for neutron stars. The Laser Interferometer Space Antenna (LISA) is expected to see hundreds of these extreme mass ratio inspirals per year. Since the event rate derived here formally diverges as M . → 0, the model presented here cannot hold for MBHs of masses that are too low, and we discuss what the limitations of the model are.

REVISED MASS-TO-LIGHT RATIOS FOR NEARBY GALAXY GROUPS AND CLUSTERS

International Nuclear Information System (INIS)

Shan, Yutong; Courteau, Stéphane; McDonald, Michael

2015-01-01

We present a detailed investigation of the cluster stellar mass-to-light (M*/L) ratio and cumulative stellar masses, derived on a galaxy-by-galaxy basis, for 12 massive (M 500 ∼ 10 14 -10 15 M ☉ ), nearby clusters with available optical imaging data from the Sloan Digital Sky Survey Data Release 10 and X-ray data from the Chandra X-ray Observatory. Our method involves a statistical cluster membership using both photometric and spectroscopic redshifts when available to maximize completeness while minimizing contamination effects. We show that different methods of estimating the stellar mass-to-light ratio from observed photometry result in systematic discrepancies in the total stellar masses and average mass-to-light ratios of cluster galaxies. Nonetheless, all conversion methodologies point to a lack of correlation between M*/L i and total cluster mass, even though low-mass groups contain relatively more blue galaxies. We also find no statistically significant correlation between M*/L i and the fraction of blue galaxies (g – i < 0.85). For the mass range covered by our sample, the assumption of a Chabrier initial mass function (IMF) yields an integrated M*/L i ≅ 1.7 ± 0.2 M ☉ /L i, ☉ , a lower value than used in most similar studies, though consistent with the study of low-mass galaxy groups by Leauthaud et al. A light (diet) Salpeter IMF would imply a ∼60% increase in M*/L i

On the continuum theory of the two-fluid solar wind for small mass ratio

International Nuclear Information System (INIS)

Johnson, R.S.

1976-01-01

The continuum theory for the two-fluid solar wind is considered. The fluid is assumed to be a fully ionized neutral plasma of electrons and protons which is compressible, viscous and heat conducting with a constant Prandtl number and a viscosity proportional to (temperature) sup(ω), ω > 1. The gas is under the influence of a gravitational field centred on the Sun. It is assumed that the bulk velocity (at any point) is the same for both electrons and protons, but that an energy transfer can occur between the two species due to binary (Coulomb) collisions. The equations are non-dimensionalized and it is shown that the natural parameter to use in the construction of an asymptotic solution is the mass ratio. The limit mass ratio → zero corresponds to the small Prandtl number limit for the one-fluid theory developed by Johnson (Proc. R. Soc. (Lond) A; 347:537 (1976)). By using the method of matched asymptotic expansions, a solution is constructed that starts from the base of the corona and extends out to a diffuse shock layer. The results obtained exactly parallel the one-fluid theory and many details are identified and absorbed into this analysis. It is shown how the temperatures in the corona eventually become the well-known behaviours: rsup(-2/7) (electrons), rsup(-6/7) (protons) when ω = 5/2 and r is the radial coordinate. However, the continuum theory will probably have failed in the shock layer region - the more so since this occurs at about 100 light years distance - and further mathematical details are omitted. The numerical estimates given here compare tolerably well with the observed data and very favourably with other work on the same equations. (author)

Electron-capture ratios in radio-active decay

International Nuclear Information System (INIS)

Pelt, J. van.

1978-01-01

A review of the theory of electron capture is given and expressions for the electron-capture ratios derived. Attention is paid to the calculations of exchange and overlap correction factors. The theoretical results are then compared with experimental values on the basis of two recently published compilations. The experimental set-up used in this investigation is described and the analysis of the scintillation spectra discussed. Measurements on 131 Ba, 106 Agsup(m) and 196 Au are described and values derived for the exchange and overlap corrections and for the atomic electron-capture transition energy Qsub(EC). (Auth.)

The mass of the electron neutrino and electron capture in 163Ho

International Nuclear Information System (INIS)

Yasumi, S.; Rajasekaran, G.; Ando, M.; Ochiai, F.; Ikeda, H.; Ohta, T.; Stefan, P.M.; Maruyama, M.; Nashimoto, N.; Fujioka, M.; Ishii, K.; Shinozuka, T.; Sera, K.; Omori, T.; Izawa, G.; Yagi, M.; Masumoto, K.; Shima, K.

1983-01-01

To determine the mass of the electron neutrino, electron capture in 163 Ho was studied. From the intensity of M X-rays and the total number of 163 Ho atoms in a source, as determined by the PIXE method, the partial M-capture half life of 163 Ho was estimated to be (4.5 +- 1.5) x 10 4 yr. A relation between the Q-value of 163 Ho and the mass of the electron neutrino was obtained. (orig.)

Study of the matrix specific mass discrimination effects during inductively coupled plasma mass spectrometry isotope ratio measurements

International Nuclear Information System (INIS)

Vassileva, E.; Quetel, Ch.R.

2004-01-01

Sample matrix related effects on mass discrimination during inductively coupled plasma mass spectrometry (ICP-MS) isotope ratio measurements have only been rarely reported. However, they can lead to errors larger than the uncertainty claimed on the ratio results when not properly taken into account or corrected for. These matrix specific affects were experienced during an Isotope Dilution Mass Spectrometry (IDMS) campaign we carried out for the certification of the Cd amount content in some food digest samples (7% acidity and salts content around 450μg g -1 ). Dilution was not possible for Cd only present at the low ng g -1 level. Up to 1% difference was observed on Cd isotope ratio results between measurements performed directly or after matrix separation. This was a significant difference considering that less than 1.5% relative combined uncertainty was eventually estimated for these IDMS measurements. Similar results could be obtained either way after the implementation of necessary corrections. The direct measurement approach associated to a correction for mass discrimination effects using the food digest sample itself (and the IUPAC table values as reference for the natural Cd isotopic composition) was preferred as it was the easiest. Consequently, the impact of matrix effects on mass discrimination during isotope ratio measurements with two types of ICP- MS (quadrupole and magnetic sector instruments) was studied for 4 elements (Li, Cu, Cd and Tl). Samples of varying salinity (up to 0.25%) and acidity (up to 7%) characteristics were prepared using isotopic certified reference materials of these elements. The long term and short-term stability, respectively reproducibility and repeatability, of the results, as well as the evolution of the difference to certified ratio values were monitored. As expected the 13 investigated isotopic ratios were all sensitive to variations in salt and acid concentrations. Our experiments also showed that simultaneous variation

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

International Nuclear Information System (INIS)

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

2015-01-01

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. (paper)

Accurate isotope ratio mass spectrometry. Some problems and possibilities

International Nuclear Information System (INIS)

Bievre, P. de

1978-01-01

The review includes reference to 190 papers, mainly published during the last 10 years. It covers the following: important factors in accurate isotope ratio measurements (precision and accuracy of isotope ratio measurements -exemplified by determinations of 235 U/ 238 U and of other elements including 239 Pu/ 240 Pu; isotope fractionation -exemplified by curves for Rb, U); applications (atomic weights); the Oklo natural nuclear reactor (discovered by UF 6 mass spectrometry at Pierrelatte); nuclear and other constants; isotope ratio measurements in nuclear geology and isotope cosmology - accurate age determination; isotope ratio measurements on very small samples - archaeometry; isotope dilution; miscellaneous applications; and future prospects. (U.K.)

The Mass-Ratio Distribution of Visual Binary Stars

NARCIS (Netherlands)

Hogeveen, S.J.

1990-01-01

The selection effects that govern the observations of Visual Binary Stars are in- vestigated, in order to obtain a realistic statistical distribution of the mass-ratio q = Msec=Mprim. To this end a numerical simulation programme has been developed, which `generates' binary stars and `looks' at

Limits on the electron-antineutrino mass

International Nuclear Information System (INIS)

Wilkerson, J.F.

1987-01-01

New measurements near the endpoint of the tritium beta-decay spectrum are producing limits on the electron-antineutrino mass which are below the central mass value of 30 eV reported by ITEP. The factors that influence the neutrino mass sensitivity of tritium beta decay measurements will be discussed followed by a review of the current experimental results. 9 refs., 5 figs., 2 tabs

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

Energy Technology Data Exchange (ETDEWEB)

Kelly, Brandon C. [Department of Physics, Broida Hall, University of California, Santa Barbara, CA 93107 (United States); Shen, Yue [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-51, Cambridge, MA 02138 (United States)

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.

BINARY FORMATION MECHANISMS: CONSTRAINTS FROM THE COMPANION MASS RATIO DISTRIBUTION

International Nuclear Information System (INIS)

Reggiani, Maddalena M.; Meyer, Michael R.

2011-01-01

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/dq∝q β , with β = -0.50 ± 0.29, consistent with previous results. Finally, we note that the Kolmogorov-Smirnov test gives a ∼1

GALAXY MERGERS AND DARK MATTER HALO MERGERS IN ΛCDM: MASS, REDSHIFT, AND MASS-RATIO DEPENDENCE

International Nuclear Information System (INIS)

Stewart, Kyle R.; Bullock, James S.; Barton, Elizabeth J.; Wechsler, Risa H.

2009-01-01

We employ a high-resolution ΛCDM N-body simulation to present merger rate predictions for dark matter (DM) halos and investigate how common merger-related observables for galaxies-such as close pair counts, starburst counts, and the morphologically disturbed fraction-likely scale with luminosity, stellar mass, merger mass ratio, and redshift from z = 0 to z = 4. We investigate both rate at which subhalos first enter the virial radius of a larger halo (the 'infall rate'), and the rate at which subhalos become destroyed, losing 90% of the mass they had at infall (the d estruction rate ) . For both merger rate definitions, we provide a simple 'universal' fitting formula that describes our derived merger rates for DM halos a function of dark halo mass, merger mass ratio, and redshift, and go on to predict galaxy merger rates using number density matching to associate halos with galaxies. For example, we find that the instantaneous (destruction) merger rate of m/M > 0.3 mass-ratio events into typical L ∼> f L * galaxies follows the simple relation dN/dt ≅ 0.03(1 + f) Gyr -1 (1 + z) 2.1 . Despite the rapid increase in merger rate with redshift, only a small fraction of >0.4 L * high-redshift galaxies (∼3% at z = 2) should have experienced a major merger (m/M > 0.3) in the very recent past (t 0.3) in the previous 700 Myr and conclude that mergers almost certainly play an important role in delivering baryons and influencing the kinematic properties of Lyman break galaxies (LBGs).

THE ELECTRONIC COURSE OF HEAT AND MASS TRANSFER

Directory of Open Access Journals (Sweden)

Alexander P. Solodov

2013-01-01

Full Text Available The Electronic course of heat and mass transfer in power engineering is presented containing the full Electronic book as the structured hypertext document, the full set of Mathcad-documents with the whole set of educative computer models of heat and mass transfer, the computer labs, and selected educational presentations. 

A New Mass Criterium for Electron Capture Supernovae

Science.gov (United States)

Poelarends, Arend

2016-06-01

Electron capture supernovae (ECSN) are thought to populate the mass range between massive white dwarf progenitors and core collapse supernovae. It is generally believed that the initial stellar mass range for ECSN from single stars is about 0.5-1.0 M⊙ wide and centered around a value of 8.5 or 9 M⊙, depending on the specifics of the physics of convection and mass loss one applies. Since mass loss in a binary system is able to delay or cancel the second dredge-up, it is also believed that the initial mass range for ECSN in binary systems is wider than in single stars, but an initial mass range has not been defined yet.The last phase of stars in this particular mass range, however, is challenging to compute, either due to recurring Helium shell flashes, or due to convectively bound flames in the degenerate interior of the star. It would be helpful, nevertheless, to know before we enter these computationally intensive phases whether a star will explode as an ECSN or not. The mass of the helium core after helium core burning is one such criterium (Nomoto, 1984), which predicts that ECSN will occur if the helium core mass is between 2.0 M⊙ and 2.5 M⊙. However, since helium cores can be subject to erosion due to mass loss — even during helium core burning, this criterium will not yield accurate predictions for stars in binary systems.We present a dense grid of stellar evolution models that allow us to put constraints on the final fate of their cores, based on a combination of Carbon/Oxygen core mass, the mass of the surrounding Helium layer and C/O abundance. We find that CO cores with masses between 1.365 and 1.420 M⊙ at the end of Carbon burning will result in ECSN, with some minor adjustments of these ranges due to the mass of the Helium layer and the C/O ratio. While detailed models of stars within the ECSN mass range remain necessary to understand the details of pre-ECSN evolution, our research refines the Helium core criterion and provides a useful way

Electronic branching ratio of the τ lepton

International Nuclear Information System (INIS)

Ammar, R.; Baringer, P.; Coppage, D.; Davis, R.; Kelly, M.; Kwak, N.; Lam, H.; Ro, S.; Kubota, Y.; Lattery, M.; Nelson, J.K.; Perticone, D.; Poling, R.; Schrenk, S.; Wang, R.; Alam, M.S.; Kim, I.J.; Nemati, B.; Romero, V.; Sun, C.R.; Wang, P.; Zoeller, M.M.; Crawford, G.; Fulton, R.; Gan, K.K.; Kagan, H.; Kass, R.; Lee, J.; Malchow, R.; Morrow, F.; Sung, M.K.; Whitmore, J.; Wilson, P.; Butler, F.; Fu, X.; Kalbfleisch, G.; Lambrecht, M.; Skubic, P.; Snow, J.; Wang, P.; Bortoletto, D.; Brown, D.N.; Dominick, J.; McIlwain, R.L.; Miller, D.H.; Modesitt, M.; Shibata, E.I.; Schaffner, S.F.; Shipsey, I.P.J.; Battle, M.; Ernst, J.; Kroha, H.; Roberts, S.; Sparks, K.; Thorndike, E.H.; Wang, C.; Stroynowski, R.; Artuso, M.; Goldberg, M.; Haupt, T.; Horwitz, N.; Kennett, R.; Moneti, G.C.; Playfer, S.; Rozen, Y.; Rubin, P.; Skwarnicki, T.; Stone, S.; Thulasidas, M.; Yao, W.; Zhu, G.; Barnes, A.V.; Bartelt, J.; Csorna, S.E.; Jain, V.; Letson, T.; Mestayer, M.D.; Akerib, D.S.; Barish, B.; Chadha, M.; Cowen, D.F.; Eigen, G.; Miller, J.S.; Urheim, J.; Weinstein, A.J.; Morrison, R.J.; Tajima, H.; Schmidt, D.; Sperka, D.; Procario, M.; Daoudi, M.; Ford, W.T.; Johnson, D.R.; Lingel, K.; Lohner, M.; Rankin, P.; Smith, J.G.; Alexander, J.; Bebek, C.; Berkelman, K.; Besson, D.; Browder, T.E.; Cassel, D.G.; Cheu, E.; Coffman, D.M.; Drell, P.S.; Ehrlich, R.; Galik, R.S.; Garcia-Sciveres, M.; Geiser, B.; Gittelman, B.; Gray, S.W.; Hartill, D.L.; Heltsley, B.K.; Honscheid, K.; Jones, C.; Kandaswamy, J.; Katayama, N.; Kim, P.C.; Kreinick, D.L.; Ludwig, G.S.; Masui, J.; Mevissen, J.; Mistry, N.B.; Nandi, S.; Ng, C.R.; Nordberg, E.; O'Grady, C.; Patterson, J.R.; Peterson, D.; Riley, D.; Sapper, M.; Selen, M.; Worden, H.; Worris, M.; Wuerthwein, F.; Avery, P.; Freyberger, A.; Rodriguez, J.; Yelton, J.; Henderson, S.; Kinoshita, K.; Pipkin, F.; Saulnier, M.; Wilson, R.; Wolinski, J.; Xiao, D.; Yamamoto, H.; Sadoff, A.J.

1992-01-01

Using data accumulated by the CLEO I detector operating at the Cornell Electron Storage Ring, we have measured the ratio R=Γ(τ→e bar ν e ν τ )/Γ 1 , where Γ 1 is the τ decay rate to final states with one charged particle. We find R=0.2231±0.0044±0.0073 where the first error is statistical and the second is systematic. Together with the measured topological one-charged-particle branching fraction, this yields the branching fraction of the τ lepton to electrons, B e =0.192±0.004±0.006

Effect of electrode mass ratio on aging of activated carbon based supercapacitors utilizing organic electrolytes

Science.gov (United States)

Cericola, D.; Kötz, R.; Wokaun, A.

2011-03-01

The accelerated degradation of carbon based supercapacitors utilizing 1 M Et4NBF4 in acetonitrile and in propylene carbonate as electrolyte is investigated for a constant cell voltage of 3.5 V as a function of the positive over total electrode mass ratio. The degradation rate of the supercapacitor using acetonitrile as a solvent can be decreased by increasing the mass of the positive electrode. With a mass ratio (positive electrode mass/total electrode mass) of 0.65 the degradation rate is minimum. For the capacitor utilizing propylene carbonate as a solvent a similar effect was observed. The degradation rate was smallest for a mass ratio above 0.5.

Renormalization of effective mass in self-assembled quantum dots due to electron-electron interactions

International Nuclear Information System (INIS)

Babinski, A; Korkusinski, M; Hawrylak, P; Wasilewski, Z R; Potemski, M

2013-01-01

Magnetic-field dispersion of the multiexcitons related to the p shell of a single quantum dot (QD) is analysed in this work. The reduced cyclotron effective mass of carriers is determined from the energy splitting between the p + - and p − - related multiexcitonic emission lines. The reduced mass in the occupied QD was found to be larger than the mass related to the QD's single particle structure. The apparent increase of the reduced mass with increasing excitonic occupation of the dot is related to the mass renoralization due to electron-electron interactions within a multiexcitonic droplet

Effect of ion and ion-beam mass ratio on the formation of ion-acoustic solitons in magnetized plasma in the presence of electron inertia

International Nuclear Information System (INIS)

Kalita, B. C.; Barman, S. N.

2009-01-01

The propagation of ion-acoustic solitary waves in magnetized plasma with cold ions and ion-beams together with electron inertia has been investigated theoretically through the Korteweg-de Vries equation. Subject to the drift velocity of the ion beam, the existence of compressive solitons is found to become extinct as α (=cold ion mass/ion-beam mass) tends to 0.01 when γ=0.985 (γ is the beam velocity/phase velocity). Interestingly, a transitional direction of propagation of solitary waves has been unearthed for change over, from compressive solitons to rarefactive solitons based on α and σ υ (=cosine of the angle θ made by the wave propagation direction ξ with the direction of the magnetic field) for fixed Q(=electron mass/ion mass). Further, the direction of propagation of ion-acoustic waves is found to be the deterministic factor to admit compressive or rarefactive solitons subject to beam outsource.

Electronic drive and acquisition system for mass spectrometry

Science.gov (United States)

Schaefer, Rembrandt Thomas (Inventor); Mojarradi, Mohammad (Inventor); Chutjian, Ara (Inventor); Darrach, Murray R. (Inventor); MacAskill, John (Inventor); Tran, Tuan (Inventor); Burke, Gary R. (Inventor); Madzunkov, Stojan M. (Inventor); Blaes, Brent R. (Inventor); Thomas, John L. (Inventor)

2010-01-01

The present invention discloses a mixed signal RF drive electronics board that offers small, low power, reliable, and customizable method for driving and generating mass spectra from a mass spectrometer, and for control of other functions such as electron ionizer, ion focusing, single-ion detection, multi-channel data accumulation and, if desired, front-end interfaces such as pumps, valves, heaters, and columns.

Observing extreme-mass-ratio inspirals with eLISA/NGO

OpenAIRE

Gair, Jonathan R; Porter, Edward K

2012-01-01

The extreme-mass-ratio inspirals (EMRIs) of stellar mass compact objects into massive black holes in the centres of galaxies are an important source of low-frequency gravitational waves for space-based detectors. We discuss the prospects for detecting these sources with the evolved Laser Interferometer Space Antenna (eLISA), recently proposed as an ESA mission candidate under the name NGO. We show that NGO could observe a few tens of EMRIs over its two year mission lifetime at redshifts z < 0...

A Universal Break in the Planet-to-star Mass-ratio Function of Kepler MKG Stars

Science.gov (United States)

Pascucci, Ilaria; Mulders, Gijs D.; Gould, Andrew; Fernandes, Rachel

2018-04-01

We follow the microlensing approach and quantify the occurrence of Kepler exoplanets as a function of planet-to-star mass ratio, q, rather than planet radius or mass. For planets with radii ∼1–6 R ⊕ and periods law with a break at ∼3 × 10‑5 independent of host type for hosts below 1 M ⊙. These findings indicate that the planet-to-star mass ratio is a more fundamental quantity in planet formation than planet mass. We then compare our results to those from microlensing for which the overwhelming majority satisfies the M host common planet inside the snowline is ∼3–10 times less massive than the one outside. With rocky planets interior to gaseous planets, the solar system broadly follows the combined mass-ratio function inferred from Kepler and microlensing. However, the exoplanet population has a less extreme radial distribution of planetary masses than the solar system. Establishing whether the mass-ratio function beyond the snowline is also host type independent will be crucial to build a comprehensive theory of planet formation.

Limits on the production of large transverse momentum direct photons deduced from the measurement of low-mass electron pairs

International Nuclear Information System (INIS)

Cobb, J.H.; Iwata, S.; Palmer, R.B.; Rahm, D.C.; Rehak, P.; Stumer, I.; Fabjan, C.W.; Fowler, E.; Mannelli, I.; Mouzourakis, P.; Nakamura, K.; Nappi, A.; Willis, W.J.; Goldberg, M.; Horwitz, N.; Moneti, G.C.; Lankford, A.J.; Kourkoumelis, C.

1978-01-01

The hadronic production of electron pairs with masses between 200 and 500 MeV and large transverse momentum has been measured at the CERN Intersecting Storage Rings (ISR). The expected relation between low-mass electron pairs and real photons is used to determine the direct hadronic production of photons. Contrary to indications from some previous experiments, the observed spectrum is consistent with expectations from the decay of known mesons, and leads to a value for the ratio of direct photons to π 0 of γ/π 0 =(0.55+-0.92)% for 2 = 55 GeV. (Auth.)

Differentiation of endogenous and exogenous steroids by gas chromatography-combustion-mass spectrometry isotope ratio

International Nuclear Information System (INIS)

Montes de Oca Porto, Rodny; Rosado Perez, Aristides; Correa Vidal, Margarita Teresa

2007-01-01

Urinary steroids profiles are used to control the misuse of endogenous steroids such as testosterone and dihydrotestosterone. The testosterone/epistestosterone ratio, measured by Gas Chromatography-Mass Spectrometry, is used to control testosterone administration. When T/E ratio is higher than 4, consumption of testosterone or its precursors is suspected. Recent researches have demonstrated the effectiveness of Carbon Isotope Ratio Mass Spectrometry to detect and confirm endogenous steroids administration. The ratio of the two stable carbon isotopes 1 3 C and 1 2 C allows the differentiation of natural and synthetic steroids because synthetic steroids have lower 1 3 C abundance. In fact, the carbon isotope ratios can be used to determine endogenous steroids administration even when testosterone/epistestosterone ratio is at its normal value. In the current work, some of the most important aspects related to differentiation of endogenous and exogenous steroids by means of Gas Chromatography-Combustion-Isotope Ratio Mass Spectrometry are discussed. Also, this article provides a review about the purification and sample preparation previous to the analysis, and diet effects on carbon isotope ratio of endogenous anabolics steroids is presented too

Determining mass-to-light ratios in elliptical galaxies

International Nuclear Information System (INIS)

Mathews, W.G.

1988-01-01

If the endstate of cooling hot gas in elliptical galaxies is a population of optically dark, low-mass stars near the galactic cores, the mass-to-light ratio could be expected to vary significantly with projected radius. No strong variation in M/L is observed. To investigate the sensitivity and reliability of observational mass-to-light determinations for a variety of galactic parameters, model galaxies having de Vaucouleurs profiles (but with central cores and outer cutoffs), variable velocity ellipsoid structure, and extended dark halos are constructed. Spurious radial variations in M/L can occur when none are present if the properties of the galactic models are processed similar to observational data. Conversely, when a population of diffuse dark stellar matter is added near the galactic cores, large gradients in M/L can escape detection. However, the magnitude of the central velocity dispersion and its variation with projected radius within the effective radius both suggest that a component of dark stars is unlikely to be more massive than about 30 times the core mass of luminous stars. This restriction is important in establishing the initial mass function of stars in elliptical galaxies and the history of winds and cooling inflows in the interstellar medium. 35 references

ORBITAL AND MASS RATIO EVOLUTION OF PROTOBINARIES DRIVEN BY MAGNETIC BRAKING

Energy Technology Data Exchange (ETDEWEB)

Zhao, Bo; Li, Zhi-Yun [Astronomy Department, University of Virginia, Charlottesville, VA 22904 (United States)

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

Dipole and Coulomb forces in electron capture dissociation and electron transfer dissociation mass spectroscopy.

Science.gov (United States)

Świerszcz, Iwona; Skurski, Piotr; Simons, Jack

2012-02-23

Ab initio electronic structure calculations were performed on a doubly charged polypeptide model H(+)-Lys(Ala)(19)-CO-CH(NH(2))-CH(2)-SS-CH(2)-(NH(2))CH-CO-(Ala)(19)-Lys-H(+) consisting of a C-terminal protonated Lys followed by a 19-Ala α-helix with a 20th Ala-like unit whose side chain is linked by a disulfide bond to a corresponding Ala-like unit connected to a second 19-Ala α-helix terminated by a second C-terminal-protonated Lys. The Coulomb potentials arising from the two charged Lys residues and dipole potentials arising from the two oppositely directed 72 D dipoles of the α-helices act to stabilize the SS bond's σ* orbital. The Coulomb potentials provide stabilization of 1 eV, while the two large dipoles generate an additional 4 eV. Such stabilization allows the SS σ* orbital to attach an electron and thereby generate disulfide bond cleavage products. Although calculations are performed only on SS bond cleavage, discussion of N-C(α) bond cleavage caused by electron attachment to amide π* orbitals is also presented. The magnitudes of the stabilization energies as well as the fact that they arise from Coulomb and dipole potentials are supported by results on a small model system consisting of a H(3)C-SS-CH(3) molecule with positive and negative fractional point charges to its left and right designed to represent (i) two positive charges ca. 32 Å distant (i.e., the two charged Lys sites of the peptide model) and (ii) two 72 D dipoles (i.e., the two α-helices). Earlier workers suggested that internal dipole forces in polypeptides could act to guide incoming free electrons (i.e., in electron capture dissociation (ECD)) toward the positive end of the dipole and thus affect the branching ratios for cleaving various bonds. Those workers argued that, because of the huge mass difference between an anion donor and a free electron, internal dipole forces would have a far smaller influence over the trajectory of a donor (i.e., in electron transfer dissociation

The measurement of mass spectrometric peak height ratio of helium isotope in trace samples

International Nuclear Information System (INIS)

Sun Mingliang

1989-01-01

An experiment study on the measurement of mass spectrometric peak height ratio of helium isotope in the trace gaseous sample is discussed by using the gas purification line designed by the authors and model VG-5400 static-vacuum noble gas mass spectrometer imported and air helium as a standard. The results show that the amount of He and Ne in natural gas sample is 99% after purification. When the amount of He in Mass Spectrometer is more than 4 x 10 -7 cm 3 STP, it's sensitivity remains stable, about 10 -4 A/cm 3 STP He and the precision of 3 He/ 4 He ratio within the following 17 days is 1.32%. The 'ABA' pattern and experiment condition in the measurement of mass spectrometric peak height ratio of He isotope are presented

Electron dose dependence of signal-to-noise ratio, atom contrast and resolution in transmission electron microscope images

International Nuclear Information System (INIS)

Lee, Z.; Rose, H.; Lehtinen, O.; Biskupek, J.; Kaiser, U.

2014-01-01

In order to achieve the highest resolution in aberration-corrected (AC) high-resolution transmission electron microscopy (HRTEM) images, high electron doses are required which only a few samples can withstand. In this paper we perform dose-dependent AC-HRTEM image calculations, and study the dependence of the signal-to-noise ratio, atom contrast and resolution on electron dose and sampling. We introduce dose-dependent contrast, which can be used to evaluate the visibility of objects under different dose conditions. Based on our calculations, we determine optimum samplings for high and low electron dose imaging conditions. - Highlights: • The definition of dose-dependent atom contrast is introduced. • The dependence of the signal-to-noise ratio, atom contrast and specimen resolution on electron dose and sampling is explored. • The optimum sampling can be determined according to different dose conditions

Cross contamination in dual inlet isotope ratio mass spectrometers

NARCIS (Netherlands)

Meijer, H.A.J.; Neubert, R.E.M.; Visser, G.H.

2000-01-01

Since the early days of geochemical isotope ratio mass spectrometry there has always been the problem of cross contamination, i.e. the contamination of the sample gas with traces of reference gas land vice versa) in a dual inlet system and the analyzer itself. This was attributable to valve leakages

Continuous flow isotope ratio mass spectrometer (CF-IRMS) and its applications in hydrocarbon research and exploration

International Nuclear Information System (INIS)

Kalpana, G.; Patil, D.J.; Kumar, B.

2004-01-01

Stable isotope ratio mass spectrometers have been widely used to determine the isotopic ratios of light elements such as hydrogen, carbon, nitrogen, oxygen and sulphur. Continuous Flow Isotope Ratio Mass Spectrometry (CFIRMS) provides reliable data on nanomole amount of sample gas without the need for cryogenic trapping using cold fingers as in dual inlet isotope ratio mass spectrometer. High sample throughput is achieved as the system is configured with automated sample preparation devices and auto samplers. This paper presents a brief description of CFIRMS exploration

Measurements of output factors with different detector types and Monte Carlo calculations of stopping-power ratios for degraded electron beams

International Nuclear Information System (INIS)

Bjoerk, Peter; Knoeoes, Tommy; Nilsson, Per

2004-01-01

The aim of the present study was to investigate three different detector types (a parallel-plate ionization chamber, a p-type silicon diode and a diamond detector) with regard to output factor measurements in degraded electron beams, such as those encountered in small-electron-field radiotherapy and intraoperative radiation therapy (IORT). The Monte Carlo method was used to calculate mass collision stopping-power ratios between water and the different detector materials for these complex electron beams (nominal energies of 6, 12 and 20 MeV). The diamond detector was shown to exhibit excellent properties for output factor measurements in degraded beams and was therefore used as a reference. The diode detector was found to be well suited for practical measurements of output factors, although the water-to-silicon stopping-power ratio was shown to vary slightly with treatment set-up and irradiation depth (especially for lower electron energies). Application of ionization-chamber-based dosimetry, according to international dosimetry protocols, will introduce uncertainties smaller than 0.3% into the output factor determination for conventional IORT beams if the variation of the water-to-air stopping-power ratio is not taken into account. The IORT system at our department includes a 0.3 cm thin plastic scatterer inside the therapeutic beam, which furthermore increases the energy degradation of the electrons. By ignoring the change in the water-to-air stopping-power ratio due to this scatterer, the output factor could be underestimated by up to 1.3%. This was verified by the measurements. In small-electron-beam dosimetry, the water-to-air stopping-power ratio variation with field size could mostly be ignored. For fields with flat lateral dose profiles (>3 x 3 cm 2 ), output factors determined with the ionization chamber were found to be in close agreement with the results of the diamond detector. For smaller field sizes the lateral extension of the ionization chamber

Measurements of output factors with different detector types and Monte Carlo calculations of stopping-power ratios for degraded electron beams.

Science.gov (United States)

Björk, Peter; Knöös, Tommy; Nilsson, Per

2004-10-07

The aim of the present study was to investigate three different detector types (a parallel-plate ionization chamber, a p-type silicon diode and a diamond detector) with regard to output factor measurements in degraded electron beams, such as those encountered in small-electron-field radiotherapy and intraoperative radiation therapy (IORT). The Monte Carlo method was used to calculate mass collision stopping-power ratios between water and the different detector materials for these complex electron beams (nominal energies of 6, 12 and 20 MeV). The diamond detector was shown to exhibit excellent properties for output factor measurements in degraded beams and was therefore used as a reference. The diode detector was found to be well suited for practical measurements of output factors, although the water-to-silicon stopping-power ratio was shown to vary slightly with treatment set-up and irradiation depth (especially for lower electron energies). Application of ionization-chamber-based dosimetry, according to international dosimetry protocols, will introduce uncertainties smaller than 0.3% into the output factor determination for conventional IORT beams if the variation of the water-to-air stopping-power ratio is not taken into account. The IORT system at our department includes a 0.3 cm thin plastic scatterer inside the therapeutic beam, which furthermore increases the energy degradation of the electrons. By ignoring the change in the water-to-air stopping-power ratio due to this scatterer, the output factor could be underestimated by up to 1.3%. This was verified by the measurements. In small-electron-beam dosimetry, the water-to-air stopping-power ratio variation with field size could mostly be ignored. For fields with flat lateral dose profiles (>3 x 3 cm2), output factors determined with the ionization chamber were found to be in close agreement with the results of the diamond detector. For smaller field sizes the lateral extension of the ionization chamber hampers

Evaluation of precision in measurements of uranium isotope ratio by thermionic mass spectrometry

International Nuclear Information System (INIS)

Moraes, N.M.P. de; Rodrigues, C.

1977-01-01

The parameters which affect the precision and accuracy of uranium isotopic ratios measurements by thermionic mass spectrometry are discussed. A statistical designed program for the analysis of the internal and external variances are presented. It was done an application of this statistical methods, in order to get mass discrimination factor, and its standard mean deviation, by using some results already published for 235 U/ 238 U ratio in NBS uranium samples, and natural uranium [pt

Stringent bounds to spatial variations of the electron-to-proton mass ratio in the Milky Way

Energy Technology Data Exchange (ETDEWEB)

Molaro, P. [INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 I, Trieste (Italy); Levshakov, S.A. [Ioffe Physical-Technical Institute, Politekhnicheskaya Str. 26, 194021 St. Petersburg (Russian Federation); Kozlov, M.G. [Petersburg Nuclear Physics Institute, Gatchina, 188300 (Russian Federation)

2009-10-15

The ammonia method, recently proposed by Flambaum and Kozlov (2007) to probe variations of the electron-to-proton mass ratio, mu=m{sub e}/m{sub p}, is applied for the first time to dense prestellar molecular clouds in the Milky Way, allowing to test DELTAmu/mu at different galactocentric distances. High quality radio-astronomical observations are used to check the presence of possible relative radial velocity offsets between the inversion transition of NH{sub 3}(J,K)=(1,1), and the CCS J{sub N}=2{sub 1}-1{sub 0} and N{sub 2}H{sup +}J=1-0 rotational transitions. Carefully selected sample of 21 NH{sub 3}/CCS pairs observed in the Perseus molecular cloud provide the offset DELTAV{sub CCS-NH{sub 3}}=36+-7{sub stat}+-13.5{sub sys}ms{sup -1}. A similar offset of DELTAV=40.8+-12.9{sub stat}ms{sup -1} between NH{sub 3}(J,K)=(1,1) and N{sub 2}H{sup +}J=1-0 has been found in an isolated dense core L183 by Pagani et al. (2009). Overall these observations provide a safe bound of a maximum offset between ammonia and the other molecules at the level of DELTAV<=100m s{sup -1}. Being interpreted in terms of DELTAmu/mu, this bound corresponds to DELTAmu/mu<=1x10{sup -7}, which is an order of magnitude more sensitive than available extragalactic constraints. Taken at face value the measured DELTAV shows positive shifts between the line centers of NH{sub 3} and these two other molecules and suggest a real offset, which would imply a DELTAmu/muapprox4x10{sup -8}. If DELTAmu/mu follows the gradient of the local gravitational potential, then the obtained results are in conflict with laboratory atomic clock experiments in the solar system by approx5 orders of magnitude, thus requiring a chameleon-type scalar field model. New measurements involving other molecules and a wider range of objects along with verification of molecular rest frequencies are currently planned to confirm these first indications.

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

Science.gov (United States)

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.

Electron mass stopping power in H2

Science.gov (United States)

Fursa, Dmitry V.; Zammit, Mark C.; Threlfall, Robert L.; Savage, Jeremy S.; Bray, Igor

2017-08-01

Calculations of electron mass stopping power (SP) of electrons in H2 have been performed using the convergent close-coupling method for incident electron energies up to 2000 eV. Convergence of the calculated SP has been established by increasing the size of the close-coupling expansion from 9 to 491 states. Good agreement was found with the SP measurements of Munoz et al. [Chem. Phys. Lett. 433, 253 (2007), 10.1016/j.cplett.2006.10.114].

Nanopteron solutions of diatomic Fermi-Pasta-Ulam-Tsingou lattices with small mass-ratio

Science.gov (United States)

Hoffman, Aaron; Wright, J. Douglas

2017-11-01

Consider an infinite chain of masses, each connected to its nearest neighbors by a (nonlinear) spring. This is a Fermi-Pasta-Ulam-Tsingou lattice. We prove the existence of traveling waves in the setting where the masses alternate in size. In particular we address the limit where the mass ratio tends to zero. The problem is inherently singular and we find that the traveling waves are not true solitary waves but rather ;nanopterons;, which is to say, waves which are asymptotic at spatial infinity to very small amplitude periodic waves. Moreover, we can only find solutions when the mass ratio lies in a certain open set. The difficulties in the problem all revolve around understanding Jost solutions of a nonlocal Schrödinger operator in its semi-classical limit.

Mass Customization in the Electronics Industry

DEFF Research Database (Denmark)

Hvam, Lars

2006-01-01

This article describes how Amercian Power Conversion (APC), a company in the electronics industry, has used the principles of mass customization to achieve major improvements of its efficiency and performance. APC sells, designs, produces, delivers, and installs large complex infrastructure systems...

Mass Customization in the electronics industry

DEFF Research Database (Denmark)

Hvam, Lars

2006-01-01

American Power Conversion (APC), a company in the electronics industry, has used the principles of mass customisation to achieve major improvements in its efficiency and performance. APC sells, designs, produces, delivers, and installs large complex infrastructure systems for data centres...

High dynamic range isotope ratio measurements using an analog electron multiplier

Czech Academy of Sciences Publication Activity Database

Williams, P.; Lorinčík, Jan; Franzreb, K.; Herwig, R.

2013-01-01

Roč. 45, č. 1 (2013), s. 549-552 ISSN 0142-2421 R&D Projects: GA MŠk ME 894 Institutional support: RVO:67985882 Keywords : Isotope ratios * electron multiplier * dynamic range Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.393, year: 2013

The density compression ratio of shock fronts associated with coronal mass ejections

Directory of Open Access Journals (Sweden)

Kwon Ryun-Young

2018-01-01

Full Text Available We present a new method to extract the three-dimensional electron density profile and density compression ratio of shock fronts associated with coronal mass ejections (CMEs observed in white light coronagraph images. We demonstrate the method with two examples of fast halo CMEs (∼2000 km s−1 observed on 2011 March 7 and 2014 February 25. Our method uses the ellipsoid model to derive the three-dimensional geometry and kinematics of the fronts. The density profiles of the sheaths are modeled with double-Gaussian functions with four free parameters, and the electrons are distributed within thin shells behind the front. The modeled densities are integrated along the lines of sight to be compared with the observed brightness in COR2-A, and a χ2 approach is used to obtain the optimal parameters for the Gaussian profiles. The upstream densities are obtained from both the inversion of the brightness in a pre-event image and an empirical model. Then the density ratio and Alfvénic Mach number are derived. We find that the density compression peaks around the CME nose, and decreases at larger position angles. The behavior is consistent with a driven shock at the nose and a freely propagating shock wave at the CME flanks. Interestingly, we find that the supercritical region extends over a large area of the shock and lasts longer (several tens of minutes than past reports. It follows that CME shocks are capable of accelerating energetic particles in the corona over extended spatial and temporal scales and are likely responsible for the wide longitudinal distribution of these particles in the inner heliosphere. Our results also demonstrate the power of multi-viewpoint coronagraphic observations and forward modeling in remotely deriving key shock properties in an otherwise inaccessible regime.

Optimal sample to tracer ratio for isotope dilution mass spectrometry: the polyisotopic case

International Nuclear Information System (INIS)

Laszlo, G.; Ridder, P. de; Goldman, A.; Cappis, J.; Bievre, P. de

1991-01-01

The Isotope Dilution Mass Spectrometry (IDMS) measurement technique provides a means for determining the unknown amount of various isotopes of an element in a sample solution of known mass. The sample solution is mixed with an auxiliary solution, or tracer, containing a known amount of the same element having the same isotopes but of different relative abundances or isotopic composition and the induced change in the isotopic composition measured by isotope mass spectrometry. The technique involves the measurement of the abundance ratio of each isotope to a (same) reference isotope in the sample solution, in the tracer solution and in the blend of the sample and tracer solution. These isotope ratio measurements, the known element amount in the tracer and the known mass of sample solution are used to calculate the unknown amount of one isotope in the sample solution. Subsequently the unknown amount of element is determined. The purpose of this paper is to examine the optimization of the ratio of the estimated unknown amount of element in the sample solution to the known amount of element in the tracer solution in order to minimize the relative uncertainty in the determination of the unknown amount of element

A review on the determination of isotope ratios of boron with mass spectrometry.

Science.gov (United States)

Aggarwal, Suresh Kumar; You, Chen-Feng

2017-07-01

The present review discusses different mass spectrometric techniques-viz, thermal ionization mass spectrometry (TIMS), inductively coupled plasma mass spectrometry (ICPMS), and secondary ion mass spectrometry (SIMS)-used to determine 11 B/ 10 B isotope ratio, and concentration of boron required for various applications in earth sciences, marine geochemistry, nuclear technology, environmental, and agriculture sciences, etc. The details of the techniques-P-TIMS, which uses Cs 2 BO 2 + , N-TIMS, which uses BO 2 - , and MC-ICPMS, which uses B + ions for bulk analysis or B - and B + ions for in situ micro-analysis with SIMS-are highlighted. The capabilities, advantages, limitations, and problems in each mass spectrometric technique are summarized. The results of international interlaboratory comparison experiments conducted at different times are summarized. The certified isotopic reference materials available for boron are also listed. Recent developments in laser ablation (LA) ICPMS and QQQ-ICPMS for solids analysis and MS/MS analysis, respectively, are included. The different aspects of sample preparation and analytical chemistry of boron are summarized. Finally, the future requirements of boron isotope ratios for future applications are also given. Presently, MC-ICPMS provides the best precision and accuracy (0.2-0.4‰) on isotope ratio measurements, whereas N-TIMS holds the potential to analyze smallest amount of boron, but has the issue of bias (+2‰ to 4‰) which needs further investigations. © 2016 Wiley Periodicals, Inc. Mass Spec Rev 36:499-519, 2017. © 2016 Wiley Periodicals, Inc.

Stable isotope ratio mass spectrometry in forensic science and food adulteration research

International Nuclear Information System (INIS)

Kumar, B.

2009-01-01

Stable Isotope Ratio Mass Spectrometry (SIRMS) is an established technique for the determination of origin of geological, biological, chemical and physio-chemical samples/materials. With the development of highly precise mass spectrometers, the stable isotope ratio determination of hydrogen, carbon, nitrogen and oxygen have gained considerable interest in the fields of forensic science and food authentication. Natural variations in the isotopic composition of lighter elements occur due to fractionation effects, resulting in the finger printing of specific isotope ratio values that are characteristic of the origin, purity, and manufacturing processes of the products and their constituents. Forensic science uses scientific and technical methods to investigate traceable evidence of criminal acts. Stable isotope ratio mass spectrometry has been applied to numerous aspects of the forensic science. The analysis of explosives such as ammonium nitrate, gun powder and tri-nitro-toluene (TNT), cases of murder, armed robbery, drug smuggling, terrorism, arson and hit and run traffic accidents are a few of them. The main types of geological evidences in such cases are mud, soil, rocks, sand, gravel, dust particles, biological materials, organic particles and anthropogenic components. Stable isotopes are used as tools to corroborate and confirm the evidential leads in the investigation of such crimes. The variation in natural abundances of carbon and nitrogen and their isotopic ratios δ 13 C and δ 15 N can identify links between items found at crime scene with those of suspect. The paper discusses the applications of SIRMS in the field of forensic science and food adulteration research

AM1 and electron impact mass spectrometry study of the ...

African Journals Online (AJOL)

Recently, in electron impact mass spectrometry (EIMS), it has been found a good correlation between the fragmentation processes of coumarins and the electronic charges of the atoms of their skeleton. In this paper, the same analytical method has been applied to 4-acyl isochroman-1,3-diones, whose mass spectra had ...

Frozen up dilaton and the GUT/Planck mass ratio

Science.gov (United States)

Davidson, Aharon; Ygael, Tomer

2017-09-01

By treating modulus and phase on equal footing, as prescribed by Dirac, local scale invariance can consistently accompany any Brans-Dicke ω-theory. We show that in the presence of a soft scale symmetry breaking term, the classical solution, if it exists, cannot be anything else but general relativistic. The dilaton modulus gets frozen up by the Weyl-Proca vector field, thereby constituting a gravitational quasi-Higgs mechanism. Assigning all grand unified scalars as dilatons, they enjoy Weyl universality, and upon symmetry breaking, the Planck (mass)2 becomes the sum of all their individual (VEV)2s. The emerging GUT/Planck (mass)2 ratio is thus ∼ ωgGUT2 / 4 π.

Electron self-mass in the semiclassical limit

International Nuclear Information System (INIS)

Pradham, T.; Khare, A.

1978-01-01

The semiclassical limit of the electron self-mass, which is the first order term in an expansion of the exact Dyson self-mass in powers of h/2π, is calculated. The result is quadratically divergent in the limit of the cut-off radius tending to zero. It is noted that the present result is quantum mechanical in the same sense as any WKB result and is exact to all orders in e 2 , in contrast to the logarithmically divergent self-mass given by other resuls. (U.K.)

A REVIEW ON MASS SPECTROMETRY DETECTORS

OpenAIRE

Khatri Neetu; Gupta Ankit; Taneja Ruchi; Bilandi Ajay; Beniwal Prashant

2012-01-01

Mass spectrometry is an analytical technique for "weighing" molecules. Obviously, this is not done with a conventional scale or balance. Instead, mass spectrometry is based upon the principle of the motion of a charged particle that is called an ion, in an electric or magnetic field. The mass to charge ratio (m/z) of the ion affects particles motion. Since the charge of an electron is known, the mass to charge ratio (m/z) is a measurement of mass of an ion. Mass spectrometry research focuses ...

Electron attachment mass spectrometry as a diagnostics for electronegative gases and plasmas

NARCIS (Netherlands)

Stoffels - Adamowicz, E.; Stoffels, W.W.; Tachibana, K.

1998-01-01

Electron attachment mass spectrometry (EAMS) has been developed to study mixtures of electronegative gases and plasmas. A quadrupole mass spectrometer (QMS) has been used to detect negative ions, formed from sampled species by attachment of low energy electrons. Varying the electron energy allows to

OGLE-2017-BLG-1434Lb: Eighth qTurnover in Planet Mass-Ratio Function

Science.gov (United States)

Udalski, A.; Ryu, Y.-H.; Sajadian, S.; Gould, A.; Mrǎłz, P.; Poleski, R.; Szymański, M. K.; Skowron, J.; Soszyński, I.; Kozłowski, S.; Pietrukowicz, P.; Ulaczyk, K.; Pawlak, M.; Rybicki, K.; Iwanek, P.; Albrow, M. D.; Chung, S.-J.; Han, C.; Hwang, K.-H.; Jung, Y., K.; Shin, I.-G.; Shvartzvald, Y.; Yee, J. C.; Zang, W.; Zhu, W.; Cha, S.-M.; Kim, D.-J.; Kim, H.-W.; Kim, S.-L.; Lee, C.-U.; Lee, D.-J.; Lee, Y.; Park, B.-G.; Pogge, R. W.; Bozza, V.; Dominik, M.; Helling, C.; Hundertmark, M.; Jørgensen, U. G.; Longa-Peña, P.; Lowry, S.; Burgdorf, M.; Campbell-White, J.; Ciceri, S.; Evans, D.; Figuera Jaimes, R.; Fujii, Y. I.; Haikala, L. K.; Henning, T.; Hinse, T. C.; Mancini, L.; Peixinho, N.; Rahvar, S.; Rabus, M.; Skottfelt, J.; Snodgrass, C.; Southworth, J.; von Essen, C.

2018-03-01

We report the discovery of a cold Super-Earth planet (mp=4.4±0.5 M⊙) orbiting a low-mass (M=0.23±0.03) M⊙ dwarf at projected separation a⊥=1.18±0.10 a.u., i.e., about 1.9 times the distance the snow line. The system is quite nearby for a microlensing planet, DL=0.86±0.09 kpc. Indeed, it was the large lens-source relative parallax πrel=1.0 mas (combined with the low mass M) that gave rise to the large, and thus well-measured, "microlens parallax" πE∝(πrel/M)1/2 that enabled these precise measurements. OGLE-2017-BLG-1434Lb is the eighth microlensing planet with planet-host mass ratio qturnover" in the mass function found by Suzuki et al. relative to the power law of opposite sign n=-0.93±0.13 at higher mass ratios q≳2×10-4. We combine our result with that of Suzuki et al. to obtain p=0.73+0.42-0.34.

The relationship between vertical cup‑disc ratio and body mass ...

African Journals Online (AJOL)

Aim: To determine the relationship between vertical cup disc ratio (VCDR) and body mass index (BMI) in a population screened for glaucoma in Port Harcourt, Nigeria Materials and Method: This study was part of a one-day screening exercise for glaucoma at the University of Port Harcourt. Demographic data included age, ...

THE STAR FORMATION HISTORIES OF RED-SEQUENCE GALAXIES, MASS-TO-LIGHT RATIOS AND THE FUNDAMENTAL PLANE

International Nuclear Information System (INIS)

Allanson, Steven P.; Hudson, Michael J.; Smith, Russell J.; Lucey, John R.

2009-01-01

This paper addresses the challenge of understanding the typical star formation histories of red-sequence galaxies, using linestrength indices and mass-to-light ratios as complementary constraints on their stellar age distribution. We first construct simple parametric models of the star formation history that bracket a range of scenarios, and fit these models to the linestrength indices of low-redshift cluster red-sequence galaxies. For giant galaxies, we confirm the downsizing trend, i.e., the stellar populations are younger, on average, for lower σ galaxies. We find, however, that this trend flattens or reverses at σ ∼ -1 . We then compare predicted stellar mass-to-light ratios with dynamical mass-to-light ratios derived from the fundamental plane (FP), or by the SAURON group. For galaxies with σ ∼ 70 km s -1 , models with a late 'frosting' of young stars and models with exponential star formation histories have stellar mass-to-light ratios that are larger than observed dynamical mass-to-light ratios by factors of 1.7 and 1.4, respectively, and so are rejected. The single stellar population (SSP) model is consistent with the FP, and requires a modest amount of dark matter (between 20% and 30%) to account for the difference between stellar and dynamical mass-to-light ratios. A model in which star formation was 'quenched' at intermediate ages is also consistent with the observations, although in this case less dark matter is required for low mass galaxies. We also find that the contribution of stellar populations to the 'tilt' of the fundamental plane is highly dependent on the assumed star formation history: for the SSP model, the tilt of the FP is driven primarily by stellar-population effects. For a quenched model, two-thirds of the tilt is due to stellar populations and only one-third is due to dark matter or non-homology.

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

Science.gov (United States)

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.

Diagnostic performance of sonoelastographic Tsukuba score and strain ratio in evaluation of breast masses

Directory of Open Access Journals (Sweden)

Mahmoud Abd Elaziz Dawood

2018-03-01

Full Text Available The aim of this prospective study was to evaluate the diagnostic performance of the use of strain index ratio by sonoelastography to differentiate between benign and malignant breast lesions. Patients & Methods: This prospective study including 40 females, complaining of breast masses which were suspicious to be malignant on clinical examination. All patients were submitted to B-mode Ultrasound and sonoelastography. Biopsy as a gold standard and pathological study were done for all breast lesions. Results: US examination of every mass was done and categorized according to BI-RADS categories according to ACR2013, according to US lexicon. Sonoelastography examination with Lesions classification was performed on the basis of a 5-point scoring method proposed by Tsukuba elasticity score. Then measurements of strain ratio were done. Statistical analysis of combination of the three methods was sensitivity of 96.7%, specificity of 100% when we use cut off value of 3–4 in elastography score and ≤3 cut off value of strain ratio. Conclusion: The combined use of strain ratio with Tsukuba score and BI-RADS categorization increased the diagnostic performance in differentiation between benign and malignant breast lesions. Keywords: Elastography, Breast masses, Strain ratio, Ultrasound, BI-RADS classification, Tsukuba score

Electronic sputtering of biomolecules and its application in mass spectrometry

International Nuclear Information System (INIS)

Haakansson, P.; Sundqvist, B.U.R.

1989-01-01

In 1974 Macfarlane discovered that fast heavy ions from a 252-Cf source can desorb and ionize molecules from a solid surface. The mass of the molecules was determined by time-of-flight technique. It has been shown that the desorption mechanism is associated with the electron part of the stopping power of the primary ion and the name 'electron sputtering' has been adopted for the phenomenon to distinguish it from the well-known sputtering process with ions of KeV energy. A review of electronic sputtering of biomolecules will be given as well as recent measurements on Langmuir-Blodgett films. One important application of electronic sputtering is in the field of mass spectrometry. With this technique large and nonvolatile molecules can be studied. Particularly adsorption of biomolecules to a nitrocellulose backing has proven to be very useful. Examples will be given of mass spectra from peptides with a molecular weight above 20,000 u. (author)

Determination of the Electron Neutrino Mass from Experiments on Electron-Capture Beta-Decay (EC)

CERN Multimedia

2002-01-01

The aim of the programme is to measure the electron-neutrino mass, for which at present an upper limit of 500~eV is known. \\\\ \\\\ The experiment studies the shape of the internal bremsstrahlung spectrum in electron-capture near its upper end-point and deduces a mass from small shape changes completely analogous to those in the well-known determination of the electron antineutrino mass in the tritium beta-minus decay. \\\\ \\\\ In a low-energy bremsstrahlung process, the capture takes place from a virtual S state associated with a radiative P~@A~S electromagnetic transition, and the resonant nature of the process leads to important enhancements of the photon intensities at low energy, in particular near the resonance energies co (X-rays). This effect gives this type of experiment a chance to compete with experiments on continuous beta spectra. \\\\ \\\\ The programme concentrates on two long-lived isotopes: \\\\ \\\\ 1)~~|1|6|3Ho. The Q value for this isotope has been found to be 2.6-2.7 keV. A detector specially construct...

Determination of Mg/Ca ratio of stalagmite by laser multicollector inductively coupled plasma mass spectrometry

International Nuclear Information System (INIS)

He Xuexian; Zhu Xiangkun; Tang Suohan; Yang Chun; Cai Junjun; Li Shizhen; Li Zhihong

2005-01-01

A method for determining Mg/Ca of stalagmite by LA-MC-ICPMS is studied. 24 Mg/ 44 Ca (Mass 22, intensity of 44C a 2+ , collected by ion counting and mass 24, intensity of 24 Mg + , collected by Faraday cup) ratios were measured in replace of Mg/Ca ratios. Both diameter of laser sampling spot and laser moving increment were 2- μm. The curve of Mg/Ca vs. distance directly was obtained. The result indicates that relative Mg/Ca ratios changed from 0.5 to 2.0 this stalagmite and it is enough to reflect environmental factors act. (authors)

Determination of SB2 masses and age: introduction of the mass ratio in the Bayesian analysis

Science.gov (United States)

Giarrusso, M.; Leone, F.; Tognelli, E.; Degl'Innocenti, S.; Prada Moroni, P. G.

2018-04-01

Stellar age assignment still represents a difficult task in Astrophysics. This unobservable fundamental parameter can be estimated only through indirect methods, as well as generally the mass. Bayesian analysis is a statistical approach largely used to derive stellar properties by taking into account the available information about the quantities we are looking for. In this paper we propose to apply the method to the double-lined spectroscopic binaries (SB2), for which the only available information about masses is the observed mass ratio of the two components. We validated the method on a synthetic sample of Pre-Main Sequence (PMS) SB2 systems showing the capability of the technique to recover the simulated age and masses. Then, we applied our procedure to the PMS eclipsing binaries Parenago 1802 and RX J0529.4+0041 A, whose masses of both components are known, by treating them as SB2 systems. The estimated masses are in agreement with those dynamically measured. We conclude that the method, if based on high resolution and high signal-to-noise spectroscopy, represents a robust way to infer the masses of the very numerous SB2 systems together with their age, allowing to date the hosting astrophysical environments.

Determination of SB2 masses and age: introduction of the mass ratio in the Bayesian analysis

Science.gov (United States)

Giarrusso, M.; Leone, F.; Tognelli, E.; Degl'Innocenti, S.; Prada Moroni, P. G.

2018-07-01

Stellar age assignment still represents a difficult task in Astrophysics. This unobservable fundamental parameter can be estimated only through indirect methods, as well as generally the mass. Bayesian analysis is a statistical approach largely used to derive stellar properties by taking into account the available information about the quantities we are looking for. In this paper, we propose to apply the method to the double-lined spectroscopic binaries (SB2), for which the only available information about masses is the observed mass ratio of the two components. We validated the method on a synthetic sample of pre-main-sequence (PMS) SB2 systems showing the capability of the technique to recover the simulated age and masses. Then, we applied our procedure to the PMS eclipsing binaries Parenago 1802 and RX J0529.4+0041 A, whose masses of both components are known, by treating them as SB2 systems. The estimated masses are in agreement with those dynamically measured. We conclude that the method, if based on high resolution and high signal-to-noise spectroscopy, represents a robust way to infer the masses of the very numerous SB2 systems together with their age, allowing to date the hosting astrophysical environments.

Search for new candidates for the neutrino-oriented mass determination by electron-capture

CERN Multimedia

Herfurth, F; Boehm, C; Blaum, K; Beck, D

2008-01-01

This proposal is part of an extended program dedicated to the neutrino-mass determination in the electron-capture sector, which aims at ultra-precise mass measurements by Penning traps in combination with cryogenic micro-calorimetry for atomic de-excitation measurements. Here, precise mass measurements with ISOLTRAP are proposed for the orbital electron-capture nuclides $^{194}$Hg and $^{202}$Pb, as well as their daughters, with the goal to determine accurately their Q-values. These values are expected to be the smallest ones among a great variety of known electron-capture precursors. Therefore, these nuclides are strong candidates for an improved electron-neutrino mass determination. We ask for 8 shifts of on-line beam at ISOLDE for mass measurements of $^{194}$Hg, $^{194}$ Au, $^{202}$Pb, and $^{202}$Tl at ISOLTRAP.

UBVRc Ic 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

International Nuclear Information System (INIS)

Samec, R. G.; Labadorf, C. M.; Hawkins, N. C.; Faulkner, D. R.; Van Hamme, W.

2011-01-01

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 v ∼ 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 ∼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.

Atomic masses of rare-earth isotopes

International Nuclear Information System (INIS)

Schmidt-Ott, W.D.; Kantus, R.; Runte, E.

1981-01-01

A survey is given of decay energies of rare-earth isotopes measured in electron-capture decay by relative Psub(K) ratios, ECsub(K)/β + , and EC/β + ratios. Atomic masses of A = 147 isotopes and of 146 Gd and 148 Dy were derived. The masses of these isotopes and of α-decaying precessors are compared with predictions of current mass formulae. The subshell closure at Z = 64 is shown for N = 82, and 84 isotones. (orig.)

USE OF GC-MS/COMBUSTION/IRMS TO IDENTIFY AND DETERMINE THE STABLE CARBON ISOTOPIC RATIO OF INDIVIDUAL LIPIDS

Science.gov (United States)

A system that couples a gas chromatograph (GC) via a split to a quadrapole mass spectrometer (MS) and, through a combustion interface, to an isotope ratio mass spectrometer (IRMS) allows the simultaneous detection of electron impact mass spectra and stable carbon isotope ratio an...

Dark matter contraction and stellar-mass-to-light ratio gradients in massive early-type galaxies

Science.gov (United States)

Oldham, Lindsay J.; Auger, Matthew W.

2018-05-01

We present models for the dark and luminous mass structure of 12 strong lensing early-type galaxies. We combine pixel-based modelling of multiband Hubble Space Telescope imaging with Jeans modelling of kinematics obtained from Keck/ESI spectra to disentangle the dark and luminous contributions to the mass. Assuming a generalised NFW (gNFW) profile for the dark matter halo and a spatially constant stellar-mass-to-light ratio ϒ⋆ for the baryonic mass, we infer distributions for ϒ⋆ consistent with initial mass functions (IMFs) that are heavier than the Milky Way's (with a global mean mismatch parameter relative to a Chabrier IMF μαc = 1.80 ± 0.14) and halo inner density slopes that span a large range but are generally cuspier than the dark-matter-only prediction (μ _{γ ^' }} = 2.01_{-0.22}^{+0.19}). We investigate possible reasons for overestimating the halo slope, including the neglect of spatially varying stellar-mass-to-light ratios and/or stellar orbital anisotropy, and find that a quarter of the systems prefer radially declining stellar-mass-to-light ratio gradients, but that the overall effect on our inference on the halo slope is small. We suggest a coherent explanation of these results in the context of inside-out galaxy growth, and that the relative importance of different baryonic processes in shaping the dark halo may depend on halo environment.

BINARY CEPHEIDS: SEPARATIONS AND MASS RATIOS IN 5 M ☉ BINARIES

International Nuclear Information System (INIS)

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

2013-01-01

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

Variability of the proton-to-electron mass ratio on cosmological scales

Science.gov (United States)

Wendt, M.; Reimers, D.

2008-10-01

The search for a possible variation of fundamental physical constants isnewsworthy more than ever. A multitude of methods were developed. So far theonly seemingly significant indication of a cosmological variation existsfor the proton-to-electron massratio as stated by Reinhold et al. [1]. The measuredindication of variation is based on the combined analysis of H2 absorptionsystems in the spectra of Q0405-443 and Q0347-383 at zabs=2.595 and zabs=3.025, respectively. The high resolution data of the latteris reanalyzed in this work to examine the influence of different fittingprocedures and further potential nonconformities. This analysis cannotreproduce the significance achieved by the previous works.

Nonambipolar electron source

International Nuclear Information System (INIS)

Longmier, B.; Baalrud, S.; Hershkowitz, N.

2006-01-01

A radio frequency (rf) plasma-based electron source that does not rely on electron emission at a cathode surface has been constructed. All of the random electron flux incident on an exit aperture is extracted through an electron sheath resulting in total nonambipolar flow within the device when the ratio of the ion loss area to the electron loss area is approximately equal to the square root of the ratio of the ion mass to the electron mass, and the ion sheath potential drop at the chamber walls is much larger than T e /e. The nonambipolar electron source (NES) has an axisymmetric magnetic field of 100 G at the extraction aperture that results in a uniform plasma potential across the aperture, allowing the extraction of all the incident electron flux without the use of grids. A prototype NES has produced 15 A of continuous electron current, using 15 SCCM (SCCM denotes cubic centimeter per minute at STP) Ar, 1200 W rf power at 13.56 MHz, and 6 times gas utilization. Alternatively 8 A of electron current can be produced, using 3 SCCM Ar at 1200 W rf and 20 times gas utilization. NES could replace hollow cathode electron sources in a wide variety of applications

Systematic study of the π-/π+ ratio in heavy-ion collisions with the same neutron/proton ratio but different masses

International Nuclear Information System (INIS)

Zhang Ming; Xiao Zhigang; Zhu Shengjiang; Li Baoan; Chen Liewen; Yong Gaochan

2009-01-01

A systematic study of the π - /π + ratio in heavy-ion collisions with the same neutron/proton ratio but different masses can help single out effects of the nuclear mean field on pion production. Based on simulations using the IBUU04 transport model, it is found that the π - /π + ratio in head-on collisions of 48 Ca+ 48 Ca, 124 Sn+ 124 Sn, and 197 Au+ 197 Au at beam energies from 0.25 to 0.6 GeV/nucleon increases with increasing the system size or decreasing the beam energies. A comprehensive analysis of the dynamical isospin fractionation and the π - /π + ratio as well as their time evolution and spatial distributions demonstrates clearly that the π - /π + ratio is an effective probe of the high-density behavior of the nuclear symmetry energy.

Mass determination based on electron scattering in electron probe X-ray microanalysis of thin biological specimens

International Nuclear Information System (INIS)

Linders, P.W.J.

1984-01-01

This thesis describes the development of a method for mass determination of thin biological objects by quantitative electron microscopy. The practical realization of the mass determination consists of photographical recording with subsequent densitometry. (Auth.)

FieldSpec: A field portable mass spectrometer prototype for high frequency measurements of δ (2) H and δ (18) O ratios in water

Science.gov (United States)

López Días, Veneranda; Quang Hoang, Hung; Martínez-Carreras, Núria; Barnich, François; Wirtz, Tom; Pfister, Laurent; McDonnell, Jeffrey

2016-04-01

Hydrological studies relying on stable water isotopes to better understand water sources, flowpaths and transit times are currently limited by the coarse temporal resolution of sampling and analysis protocols. At present, two kinds of lab-based instruments are used : (i) the standard isotope ratio mass spectrometers (IRMS) [1] and (ii) the laser-based instruments [2, 3]. In both cases, samples need to be collected in the field and then transferred to the laboratory for the water isotopic ratio measurements (even further complex sample preparation is required for the IRMS). Hence, past and ongoing research targets the development of field deployable instruments for measuring stable water isotopes at high temporal frequencies. While recent studies have demonstrated that laser-based instruments may be taken to the field [4, 5], their size and power consumption still restrict their use to sites equipped with mains power or generators. Here, we present progress on the development of a field portable mass spectrometer (FieldSpec) for direct high frequency measurements of δ2H and δ18O ratios in water. The FieldSpec instrument is based upon the use of a double focusing magnetic sector mass spectrometer in combination with an electron impact ion source and a membrane dual inlet system. The instrument directly collects liquid water samples in the field, which are then converted into water vapour before being injected into the mass spectrometer for the stable isotope analysis. δ2H and δ18O are derived from the measured mass spectra. All the components are arranged in a vacuum case having a suit case type dimension with portable electronics and battery. Proof-of-concept experiments have been carried out to characterize the instrument. The results show that the FieldSpec instrument has good linearity (R2 = 0.99). The reproducibility of the instrument ranges between 1 and 4 ‰ for δ2H and between 0.1 and 0.4 ‰ for δ18O isotopic ratio measurements. A measurement

Sr/Ca mass ratio determination in bones using fast neutron activation analysis

International Nuclear Information System (INIS)

Hult, Mikael; Fessler, Andreas

1998-01-01

The Sr/Ca mass ratio in human bones reveals information regarding the diet which is of interest in archaeology. By using fast neutron activation analysis this ratio can be measured in a non-destructive manner, which is important when bones are considered too precious to allow for destructive analysis. Simulations and measurements showed that the nuclear reactions 88 Sr(n, 2n) 87m Sr and 44 Ca(n, p) 44 K are highly useful for the purpose

Liquid and gas chromatography coupled to isotope ratio mass spectrometry for the determination of 13C-valine isotopic ratios in complex biological samples

NARCIS (Netherlands)

Godin, Jean-Philippe; Breuillé, Denis; Obled, Christiane; Papet, Isabelle; Schierbeek, Henk; Hopfgartner, Gérard; Fay, Laurent-Bernard

2008-01-01

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

On the scalar electron mass limit from single photon experiments

International Nuclear Information System (INIS)

Grivaz, J.F.

1987-03-01

We discuss how the 90% C.L. lower limit on the mass of the scalar electron, as extracted from the single photon experiments, is affected by the way the background from radiative neutrino pair production is handled. We argue that some of the results presented at the Berkeley conference are overoptimistic, and that the mass lower limit is 65 GeV rather than the advertized value of 84 GeV, for the case of degenerate scalar electrons with massless photinos

The Scattering Outcomes of Kepler Circumbinary Planets: Planet Mass Ratio

Energy Technology Data Exchange (ETDEWEB)

Gong, Yan-Xiang; Ji, Jianghui, E-mail: yxgong@pmo.ac.cn, E-mail: jijh@pmo.ac.cn [CAS Key Laboratory of Planetary Sciences, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)

2017-11-01

Recent studies reveal that the free eccentricities of Kepler-34b and Kepler-413b are much larger than their forced eccentricities, implying that scattering events may take place in their formation. The observed orbital configuration of Kepler-34b cannot be well reproduced in disk-driven migration models, whereas a two-planet scattering scenario can play a significant role of shaping the planetary configuration. These studies indicate that circumbinary planets discovered by Kepler may have experienced scattering process. In this work, we extensively investigate the scattering outcomes of circumbinary planets focusing on the effects of planet mass ratio . We find that the planetary mass ratio and the the initial relative locations of planets act as two important parameters that affect the eccentricity distribution of the surviving planets. As an application of our model, we discuss the observed orbital configurations of Kepler-34b and Kepler-413b. We first adopt the results from the disk-driven models as the initial conditions, then simulate the scattering process that occurs in the late evolution stage of circumbinary planets. We show that the present orbital configurations of Kepler-34b and Kepler-413b can be well reproduced when considering a two unequal-mass planet ejection model. Our work further suggests that some of the currently discovered circumbinary single-planet systems may be survivors of original multiple-planet systems. The disk-driven migration and scattering events occurring in the late stage both play an irreplaceable role in sculpting the final systems.

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

Science.gov (United States)

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.

Determination of the isotopic ratio 235U/238U in UF6 using quadrupole mass spectrometry

International Nuclear Information System (INIS)

Kusahara, Helena Sueco

1979-01-01

In this work measurements of isotope ratios 235 U / 23 '8U in uranium hexafluoride are carried out using a quadrupole mass spectrometer. The operational parameters, which affect the final precision of the results, are standardized. Optimized procedures for the preparation of uranium hexafluoride samples by fluorination of uranium oxides using cobalt trifluoride method are established. Careful attention is given to the process of purification of uranium hexafluoride samples by fractional distillation. Adequate statistical methods for analysing the results obtained for single ratio measurements as well as the ratio ' of isotopic ratios of sample and standard ar.e developed. A precision of about 10 -4 for single ratio measurements and accuracy of about 0,3% for the ratio of sample and standard ratios are obtained. These results agree with the values which have been obtained using magnetic mass spectrometers. The procedures and methods established in this work can be employed in the systematic uranium isotope analysis in UF 6 form. (author)

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).

Science.gov (United States)

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.

Negative-mass mitigation of Coulomb repulsion for terahertz undulator radiation of electron bunches

Energy Technology Data Exchange (ETDEWEB)

Balal, N.; Magory, E. [Ariel University, Ariel 40700 (Israel); Bandurkin, I. V. [Institute of Applied Physics, Russian Academy of Sciences, 46 Ulyanov St., Nizhny Novgorod 603950 (Russian Federation); Bratman, V. L. [Ariel University, Ariel 40700 (Israel); Institute of Applied Physics, Russian Academy of Sciences, 46 Ulyanov St., Nizhny Novgorod 603950 (Russian Federation); Savilov, A. V. [Institute of Applied Physics, Russian Academy of Sciences, 46 Ulyanov St., Nizhny Novgorod 603950 (Russian Federation); Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Avenue, Nizhny Novgorod 603950 (Russian Federation)

2015-10-19

It is proposed to utilize the effect of negative mass for stabilization of the effective axial size of very dense and short electron bunches produced by photo-injector guns by using combined undulator and strong uniform magnetic fields. It has been shown that in the “abnormal” regime, an increase in the electron energy leads to a decrease in the axial velocity of the electron; due to the negative-mass effect, the Coulomb repulsion of electrons leads to their attraction and formation of a fairly stable and compact bunch “nucleus.” An undulator with a strong uniform magnetic field providing the negative-mass effect is designed for an experimental source of terahertz radiation. The use of the negative-mass regime in this experiment should result in a long-pulse coherent spontaneous undulator emission from a short dense moderately relativistic (5.5 MeV) photo-injector electron bunch with a high (up to 20%) efficiency and a narrow frequency spectrum.

Black hole fusion in the extreme mass ratio limit

Science.gov (United States)

Emparan, Roberto; Martínez, Marina; Zilhão, Miguel

2018-02-01

We present a simple, general, and accurate construction of the event horizons for the fusion of two neutral, rotating black holes with arbitrary orientation and values of their spins, in the extreme mass ratio limit where one black hole is much larger than the other. We compute several parameters that characterize the fusion and investigate their dependence on the black hole spin and orientation axis. We also exhibit and study the appearance of transient toroidal topology of the horizon. An earlier conjecture about universal critical exponents before and after an axisymmetric pinch is proven.

Formation of Low-Mass X-Ray Binaries. II. Common Envelope Evolution of Primordial Binaries with Extreme Mass Ratios

Science.gov (United States)

Kalogera, Vassiliki; Webbink, Ronald F.

1998-01-01

We study the formation of low-mass X-ray binaries (LMXBs) through helium star supernovae in binary systems that have each emerged from a common envelope phase. LMXB progenitors must satisfy a large number of evolutionary and structural constraints, including survival through common envelope evolution, through the post-common envelope phase, where the precursor of the neutron star becomes a Wolf-Rayet star, and survival through the supernova event. Furthermore, the binaries that survive the explosion must reach interaction within a Hubble time and must satisfy stability criteria for mass transfer. These constraints, imposed under the assumption of a symmetric supernova explosion, prohibit the formation of short-period LMXBs transferring mass at sub-Eddington rates through any channel in which the intermediate progenitor of the neutron star is not completely degenerate. Barring accretion-induced collapse, the existence of such systems therefore requires that natal kicks be imparted to neutron stars. We use an analytical method to synthesize the distribution of nascent LMXBs over donor masses and orbital periods and evaluate their birthrate and systemic velocity dispersion. Within the limitations imposed by observational incompleteness and selection effects, and our neglect of secular evolution in the LMXB state, we compare our results with observations. However, our principal objective is to evaluate how basic model parameters (common envelope ejection efficiency, rms kick velocity, primordial mass ratio distribution) influence these results. We conclude that the characteristics of newborn LMXBs are primarily determined by age and stability constraints and the efficiency of magnetic braking and are largely independent of the primordial binary population and the evolutionary history of LMXB progenitors (except for extreme values of the average kick magnitude or of the common envelope ejection efficiency). Theoretical estimates of total LMXB birthrates are not credible

LISA extreme-mass-ratio inspiral events as probes of the black hole mass function

International Nuclear Information System (INIS)

Gair, Jonathan R.; Tang, Christopher; Volonteri, Marta

2010-01-01

One of the sources of gravitational waves for the proposed space-based gravitational wave detector, the Laser Interferometer Space Antenna (LISA), are the inspirals of compact objects into supermassive black holes in the centers of galaxies--extreme-mass-ratio inspirals (EMRIs). Using LISA observations, we will be able to measure the parameters of each EMRI system detected to very high precision. However, the statistics of the set of EMRI events observed by LISA will be more important in constraining astrophysical models than extremely precise measurements for individual systems. The black holes to which LISA is most sensitive are in a mass range that is difficult to probe using other techniques, so LISA provides an almost unique window onto these objects. In this paper we explore, using Bayesian techniques, the constraints that LISA EMRI observations can place on the mass function of black holes at low redshift. We describe a general framework for approaching inference of this type--using multiple observations in combination to constrain a parametrized source population. Assuming that the scaling of the EMRI rate with the black-hole mass is known and taking a black-hole distribution given by a simple power law, dn/dlnM=A 0 (M/M * ) α 0 , we find that LISA could measure the parameters to a precision of Δ(lnA 0 )∼0.08, and Δ(α 0 )∼0.03 for a reference model that predicts ∼1000 events. Even with as few as 10 events, LISA should constrain the slope to a precision ∼0.3, which is the current level of observational uncertainty in the low-mass slope of the black-hole mass function. We also consider a model in which A 0 and α 0 evolve with redshift, but find that EMRI observations alone do not have much power to probe such an evolution.

A comparison of men's and women's strength to body mass ratio and varus/valgus knee angle during jump landings.

Science.gov (United States)

Haines, Tracie L; McBride, Jeffrey M; Triplett, N Travis; Skinner, Jared W; Fairbrother, Kimberly R; Kirby, Tyler J

2011-10-01

The purpose of this investigation was to compare valgus/varus knee angles during various jumps and lower body strength between males and females relative to body mass. Seventeen recreationally active females (age: 21.94 ± 2.59 years; height: 1.67 ± 0.05 m; mass: 64.42 ± 8.39 kg; percent body fat: 26.89 ± 6.26%; squat one-repetition maximum: 66.18 ± 19.47 kg; squat to body mass ratio: 1.03 ± 0.28) and 13 recreationally active males (age: 21.69 ± 1.65 years; height: 1.77 ± 0.07 m; mass: 72.39 ± 9.23 kg; percent body fat: 13.15 ± 5.18%; squat one-repetition maximum: 115.77 ± 30.40 kg; squat to body mass ratio: 1.59 ± 0.31) performed a one-repetition maximum in the squat and three of each of the following jumps: countermovement jump, 30 cm drop jump, 45 cm drop jump, and 60 cm drop jump. Knee angles were analysed using videography and body composition was analysed by dual-energy X-ray absorptiometry to allow for squat to body mass ratio and squat to fat free mass ratio to be calculated. Significant differences (P ≤ 0.05) were found between male and female one-repetition maximum, male and female squat to body mass ratio, and male and female squat to fat free mass ratio. Significant differences were found between male and female varus/valgus knee positions during maximum flexion of the right and left leg in the countermovement jump, drop jump from 30 cm, drop jump from 45 cm, and drop jump from 60 cm. Correlations between varus/valgus knee angles and squat to body mass ratio for all jumps displayed moderate, non-significant relationships (countermovement jump: r = 0.445; drop jump from 30 cm: r = 0.448; drop jump from 45 cm: r = 0.449; drop jump from 60 cm: r = 0.439). In conclusion, males and females have significantly different lower body strength and varus/valgus knee position when landing from jumps.

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

International Nuclear Information System (INIS)

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

2015-01-01

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 PO 4 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. (paper)

Carbon/Hydrogen ratio determination in hydrocarbons and its mixtures by electron backscattering technique

International Nuclear Information System (INIS)

Padron, I.; Desdin, L.F.; Navarro, A.; Fuentes, M.

1996-01-01

A method carbon/hydrogen ratio (C/H) determination in hydrocarbons and its mixtures was improved using the electron backscattering technique. Besides the hetero atoms (S,O and N) influence in petroleum is studied for being able to determinate the C/H ratio in cuban petroleum with high sulphur contents

Mass-Gathering Medical Care in Electronic Dance Music Festivals.

Science.gov (United States)

FitzGibbon, Kathleen M; Nable, Jose V; Ayd, Benjamin; Lawner, Benjamin J; Comer, Angela C; Lichenstein, Richard; Levy, Matthew J; Seaman, Kevin G; Bussey, Ian

2017-10-01

Introduction Electronic dance music (EDM) festivals represent a unique subset of mass-gathering events with limited guidance through literature or legislation to guide mass-gathering medical care at these events. Hypothesis/Problem Electronic dance music festivals pose unique challenges with increased patient encounters and heightened patient acuity under-estimated by current validated casualty predication models. This was a retrospective review of three separate EDM festivals with analysis of patient encounters and patient transport rates. Data obtained were inserted into the predictive Arbon and Hartman models to determine estimated patient presentation rate and patient transport rates. The Arbon model under-predicted the number of patient encounters and the number of patient transports for all three festivals, while the Hartman model under-predicted the number of patient encounters at one festival and over-predicted the number of encounters at the other two festivals. The Hartman model over-predicted patient transport rates for two of the three festivals. Electronic dance music festivals often involve distinct challenges and current predictive models are inaccurate for planning these events. The formation of a cohesive incident action plan will assist in addressing these challenges and lead to the collection of more uniform data metrics. FitzGibbon KM , Nable JV , Ayd B , Lawner BJ , Comer AC , Lichenstein R , Levy MJ , Seaman KG , Bussey I . Mass-gathering medical care in electronic dance music festivals. Prehosp Disaster Med. 2017;32(5):563-567.

Maximum mass ratio of AM CVn-type binary systems and maximum white dwarf mass in ultra-compact X-ray binaries

Directory of Open Access Journals (Sweden)

Arbutina Bojan

2011-01-01

Full Text Available AM CVn-type stars and ultra-compact X-ray binaries are extremely interesting semi-detached close binary systems in which the Roche lobe filling component is a white dwarf transferring mass to another white dwarf, neutron star or a black hole. Earlier theoretical considerations show that there is a maximum mass ratio of AM CVn-type binary systems (qmax ≈ 2/3 below which the mass transfer is stable. In this paper we derive slightly different value for qmax and more interestingly, by applying the same procedure, we find the maximum expected white dwarf mass in ultra-compact X-ray binaries.

Hepatoblastoma Biology Using Isotope Ratio Mass Spectrometry: Utility of a Unique Technique for the Analysis of Oncological Specimens.

Science.gov (United States)

Taran, Katarzyna; Frączek, Tomasz; Sitkiewicz, Anna; Sikora-Szubert, Anita; Kobos, Józef; Paneth, Piotr

2016-07-07

Hepatoblastoma is the most common primary liver tumor in children. However, it occurs rarely, with an incidence of 0.5-1.5 cases per million children. There is no clear explanation of the relationship between clinicopathologic features, therapy, and outcome in hepatoblastoma cases, so far. One of the most widely accepted prognostic factors in hepatoblastoma is histology of the tumor. The aim of the study was to determine the potential differences in biology of hepatoblastoma histological subtypes at the atomic level using the unique method of isotope ratio mass spectrometry, which is especially valuable in examination of small groups of biological samples. Twenty-four measurements of nitrogen stable isotope ratio, carbon stable isotope ratio and total carbon to nitrogen mass ratio in fetal and embryonal hepatoblastoma tissue were performed using a Sercon 20-22 Continuous Flow Isotope Ratio Mass Spectrometer (CF-IRMS) coupled with a Sercon SL elemental analyzer for simultaneous carbon-nitrogen-sulfur (NCS) analysis. A difference of about 1.781‰ in stable nitrogen isotope 15N/14N ratio was found between examined hepatoblastoma histological subtypes. The prognosis in liver tumors cases in children may be challenging particularly because of the lack of versatile methods of its evaluation. Isotope ratio mass spectrometry allows one to determine the difference between hepatoblastoma histological subtypes and clearly indicates the cases with the best outcome.

Two old ways to measure the electron-neutrino mass

CERN Document Server

De Rújula, A

2013-01-01

Three decades ago, the measurement of the electron neutrino mass in atomic electron capture (EC) experiments was scrutinized in its two variants: single EC and neutrino-less double EC. For certain isotopes an atomic resonance enormously enhances the expected decay rates. The favoured technique, based on calorimeters as opposed to spectrometers, has the advantage of greatly simplifying the theoretical analysis of the data. After an initial surge of measurements, the EC approach did not seem to be competitive. But very recently, there has been great progress on micro-calorimeters and the measurement of atomic mass differences. Meanwhile, the beta-decay neutrino-mass limits have improved by a factor of 15, and the difficulty of the experiments by the cube of that figure. Can the "calorimetric" EC theory cope with this increased challenge? I answer this question affirmatively. In so doing I briefly review the subject and extensively address some persistent misunderstandings of the underlying quantum physics.

Orbital order and effective mass enhancement in t2 g two-dimensional electron gases

Science.gov (United States)

Tolsma, John; Principi, Alessandro; Polini, Marco; MacDonald, Allan

2015-03-01

It is now possible to prepare d-electron two-dimensional electron gas systems that are confined near oxide heterojunctions and contain t2 g electrons with a density much smaller than one electron per metal atom. I will discuss a generic model that captures all qualitative features of electron-electron interaction physics in t2 g two-dimensional electron gas systems, and the use of a GW approximation to explore t2 g quasiparticle properties in this new context. t2 g electron gases contain a high density isotropic light mass xy component and low-density xz and yz anisotropic components with light and heavy masses in orthogonal directions. The high density light mass band screens interactions within the heavy bands. As a result the wave vector dependence of the self-energy is reduced and the effective mass is increased. When the density in the heavy bands is low, the difference in anisotropy between the two heavy bands favors orbital order. When orbital order does not occur, interactions still reshape the heavy-band Fermi surfaces. I will discuss these results in the context of recently reported magnetotransport experiments.

A NEW CLASS OF NASCENT ECLIPSING BINARIES WITH EXTREME MASS RATIOS

Energy Technology Data Exchange (ETDEWEB)

Moe, Maxwell; Stefano, Rosanne Di, E-mail: mmoe@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-10, Cambridge, MA 02138 (United States)

2015-03-10

Early B-type main-sequence (MS) stars (M {sub 1} ≈ 5-16 M {sub ☉}) with closely orbiting low-mass stellar companions (q = M {sub 2}/M {sub 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 {sub 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 {sub 2} ≈ 0.8-2.4 M {sub ☉} (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 {sub 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.

Damping of electron center-of-mass oscillation in ultracold plasmas

International Nuclear Information System (INIS)

Chen, Wei-Ting; Witte, Craig; Roberts, Jacob L.

2016-01-01

Applying a short electric field pulse to an ultracold plasma induces an electron plasma oscillation. This manifests itself as an oscillation of the electron center of mass around the ion center of mass in the ultracold plasma. In general, the oscillation can damp due to either collisionless or collisional mechanisms, or a combination of the both. To investigate the nature of oscillation damping in ultracold plasmas, we developed a molecular dynamics model of the ultracold plasma electrons. Through this model, we found that depending on the neutrality of the ultracold plasma and the size of an applied DC electric field, there are some parameter ranges where the damping is primarily collisional and some primarily collisionless. We conducted experiments to compare the measured damping rate with theory predictions and found them to be in good agreement. Extension of our measurements to different parameter ranges should enable studies for strong-coupling influence on electron-ion collision rates.

Orientation and properties of the blends on high-molecular mass polyacrylonitrile with trihydroxyethylenedimethacrylate under electron irradiation

International Nuclear Information System (INIS)

Lomonosova, N.V.

1998-01-01

Molecular orientation of the drawn blends of high- molecular-mass poly(acrylonitrile) containing 5-50 wt % of trihydroxyethylenedimethacrylate and a change in the orientation of the drawn samples upon irradiation with accelerated electrons was studied by methods of birefringence, isometric heating, and IR dichroism. The degree of orientation of the unirradiated blends containing certain amounts of oligomer exceed that of the individual polymer. In the region of large drawing ratios, the differential degree of orientation of the polymer matrix is not affected by the irradiation, while the orientation of the oligomer component increase. High values of the strength (600-730 MPa) and the modulus (18-22 GPa) of the compositions are due to the presence of a crystalline skeleton formed by unfolded chains of the polymer matrix stabilized by the electron irradiation induced cross-linking

Electron-capture negative-ion mass spectrometry: a technique for environmental contaminant identification

International Nuclear Information System (INIS)

Stemmler, E.A.

1986-01-01

Electron capture negative ion mass spectrometry (ECNIMS) is a method used to generate negative ions in a mass spectrometer by electron-molecule reactions. This technique facilitates the sensitive and selective detection of many toxic contaminants in environmental samples. Applications of this technique have been hindered by the limited understanding of instrumental parameters, by the questionable reproducibility of negative ion mass spectra, and by the inability to interpret negative ion mass spectra. Instrumental parameters which were important to control include the ion source temperature, ion source pressure, sample concentration, and the focus lens potential. The ability to obtain reproducible spectra was demonstrated by measurement of the spectrum of decafluorotriphenylphosphine (DFTPP) over a period of one year. Negative ion fragmentation mechanisms were studied by measuring the spectra of structurally related classes of compounds and isotopically labelled compounds. These results were combined with data obtained by other researchers. Fragmentations characteristic of particular functional groups or molecular structures have been summarized. From this data set, guidelines for the interpretation of electron capture negative ion mass spectra have been developed

BINARY CEPHEIDS: SEPARATIONS AND MASS RATIOS IN 5 M {sub ☉} BINARIES

Energy Technology Data Exchange (ETDEWEB)

Evans, Nancy Remage; Karovska, Margarita; Tingle, Evan [Smithsonian Astrophysical Observatory, MS 4, 60 Garden Street, Cambridge, MA 02138 (United States); Bond, Howard E. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Schaefer, Gail H. [The CHARA Array, Georgia State University, P.O. Box 3965, Atlanta, GA 30302-3965 (United States); Mason, Brian D., E-mail: nevans@cfa.harvard.edu, E-mail: heb11@psu.edu, E-mail: schaefer@chara-array.org [US Naval Observatory, 3450 Massachusetts Avenue, NW, Washington, DC 20392-5420 (United States)

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 {sub ☉}—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 {sub ☉}. 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 {sub ☉} binaries have systematically shorter periods than do 1 M {sub ☉} 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.

Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates.

Science.gov (United States)

Moerdijk-Poortvliet, Tanja C W; Schierbeek, Henk; Houtekamer, Marco; van Engeland, Tom; Derrien, Delphine; Stal, Lucas J; Boschker, Henricus T S

2015-07-15

We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of δ(13)C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence, although LC/IRMS is expected to be more accurate and precise, no direct comparison has been reported. GC/IRMS with the aldonitrile penta-acetate (ANPA) derivatisation method was compared with LC/IRMS without derivatisation. A large number of glucose standards and a variety of natural samples were analysed for five neutral carbohydrates at natural abundance as well as at (13)C-enriched levels. Gas chromatography/chemical ionisation mass spectrometry (GC/CIMS) was applied to check for incomplete derivatisation of the carbohydrate, which would impair the accuracy of the GC/IRMS method. The LC/IRMS technique provided excellent precision (±0.08‰ and ±3.1‰ at natural abundance and enrichment levels, respectively) for the glucose standards and this technique proved to be superior to GC/IRMS (±0.62‰ and ±19.8‰ at natural abundance and enrichment levels, respectively). For GC/IRMS measurements the derivatisation correction and the conversion of carbohydrates into CO2 had a considerable effect on the measured δ(13)C values. However, we did not find any significant differences in the accuracy of the two techniques over the full range of natural δ(13)C abundances and (13)C-labelled glucose. The difference in the performance of GC/IRMS and LC/IRMS diminished when the δ(13)C values were measured in natural samples, because the chromatographic performance and background correction became critical factors, particularly for LC/IRMS. The derivatisation of carbohydrates for the GC/IRMS method was complete. Although both LC/IRMS and GC/IRMS are reliable techniques for compound-specific stable carbon isotope analysis of carbohydrates (provided that derivatisation is complete and the

Development and application of liquid chromatography coupled to isotope ratio mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Zhang, Lijun

2014-02-19

Stable isotope analysis has found widespread applications in various disciplines such as archaeology, geochemistry, biology, food authenticity, and forensic science. Coupling chromatography to isotope ratio mass spectrometry for compound-specific isotope analysis (CSIA) is a trend, as it provides several advantages over bulk isotope analysis, e.g., relatively simple sample preparation, the ability to measure individual compounds in a complex mixture in one run, and the reduced sample size required for precise isotope analysis. Gas chromatography coupled to isotope ratio mass spectrometry (GC/IRMS) has been well-established for compound-specific isotope analysis of volatile organic compounds within the last two decades. However, an interface combining liquid chromatography with isotope ratio mass spectrometry (LC/IRMS) was not commercially available until 2004. The current design of the interface requires using a carbon-free eluent in chromatographic separation. This requirement limits the application of the most frequently used reversed-phase liquid chromatography in CSIA, because the elution strength of water at room temperature is too low to serve as mobile phase in reversed-phase separations. In order to increase the elution strength of water, we propose using high temperature water for chromatographic elution. The polarity of water decreases with an increase of temperature, yielding increased elution strength in reversed-phase columns. Therefore, high temperature water can be used as eluent instead of organic solvent for combining reversed-phase liquid chromatography with isotope ratio mass spectrometry (RPLC/IRMS). Additionally, temperature gradients can replace organic solvent gradients to increase chromatographic resolution. This is very important for LC/IRMS analysis, as precise isotope analysis requires baseline separation of analytes. In this thesis, high-temperature reversed-phase liquid chromatography was coupled to, and for the first time carefully

Development and application of liquid chromatography coupled to isotope ratio mass spectrometry

International Nuclear Information System (INIS)

Zhang, Lijun

2014-01-01

Stable isotope analysis has found widespread applications in various disciplines such as archaeology, geochemistry, biology, food authenticity, and forensic science. Coupling chromatography to isotope ratio mass spectrometry for compound-specific isotope analysis (CSIA) is a trend, as it provides several advantages over bulk isotope analysis, e.g., relatively simple sample preparation, the ability to measure individual compounds in a complex mixture in one run, and the reduced sample size required for precise isotope analysis. Gas chromatography coupled to isotope ratio mass spectrometry (GC/IRMS) has been well-established for compound-specific isotope analysis of volatile organic compounds within the last two decades. However, an interface combining liquid chromatography with isotope ratio mass spectrometry (LC/IRMS) was not commercially available until 2004. The current design of the interface requires using a carbon-free eluent in chromatographic separation. This requirement limits the application of the most frequently used reversed-phase liquid chromatography in CSIA, because the elution strength of water at room temperature is too low to serve as mobile phase in reversed-phase separations. In order to increase the elution strength of water, we propose using high temperature water for chromatographic elution. The polarity of water decreases with an increase of temperature, yielding increased elution strength in reversed-phase columns. Therefore, high temperature water can be used as eluent instead of organic solvent for combining reversed-phase liquid chromatography with isotope ratio mass spectrometry (RPLC/IRMS). Additionally, temperature gradients can replace organic solvent gradients to increase chromatographic resolution. This is very important for LC/IRMS analysis, as precise isotope analysis requires baseline separation of analytes. In this thesis, high-temperature reversed-phase liquid chromatography was coupled to, and for the first time carefully

Field Sample Preparation Method Development for Isotope Ratio Mass Spectrometry

International Nuclear Information System (INIS)

Leibman, C.; Weisbrod, K.; Yoshida, T.

2015-01-01

Non-proliferation and International Security (NA-241) established a working group of researchers from Los Alamos National Laboratory (LANL), Pacific Northwest National Laboratory (PNNL) and Savannah River National Laboratory (SRNL) to evaluate the utilization of in-field mass spectrometry for safeguards applications. The survey of commercial off-the-shelf (COTS) mass spectrometers (MS) revealed no instrumentation existed capable of meeting all the potential safeguards requirements for performance, portability, and ease of use. Additionally, fieldable instruments are unlikely to meet the International Target Values (ITVs) for accuracy and precision for isotope ratio measurements achieved with laboratory methods. The major gaps identified for in-field actinide isotope ratio analysis were in the areas of: 1. sample preparation and/or sample introduction, 2. size reduction of mass analyzers and ionization sources, 3. system automation, and 4. decreased system cost. Development work in 2 through 4, numerated above continues, in the private and public sector. LANL is focusing on developing sample preparation/sample introduction methods for use with the different sample types anticipated for safeguard applications. Addressing sample handling and sample preparation methods for MS analysis will enable use of new MS instrumentation as it becomes commercially available. As one example, we have developed a rapid, sample preparation method for dissolution of uranium and plutonium oxides using ammonium bifluoride (ABF). ABF is a significantly safer and faster alternative to digestion with boiling combinations of highly concentrated mineral acids. Actinides digested with ABF yield fluorides, which can then be analyzed directly or chemically converted and separated using established column chromatography techniques as needed prior to isotope analysis. The reagent volumes and the sample processing steps associated with ABF sample digestion lend themselves to automation and field

Hepatoblastoma Biology Using Isotope Ratio Mass Spectrometry: Utility of a Unique Technique for the Analysis of Oncological Specimens

Directory of Open Access Journals (Sweden)

Katarzyna Taran

2016-07-01

Full Text Available Introduction: Hepatoblastoma is the most common primary liver tumor in children. However, it occurs rarely, with an incidence of 0.5-1.5 cases per million children. There is no clear explanation of the relationship between clinicopathologic features, therapy, and outcome in hepatoblastoma cases, so far. One of the most widely accepted prognostic factors in hepatoblastoma is histology of the tumor. The aim of the study was to determine the potential differences in biology of hepatoblastoma histological subtypes at the atomic level using the unique method of isotope ratio mass spectrometry, which is especially valuable in examination of small groups of biological samples.Material/Methods: Twenty-four measurements of nitrogen stable isotope ratio, carbon stable isotope ratio and total carbon to nitrogen mass ratio in fetal and embryonal hepatoblastoma tissue were performed using a Sercon 20-22 Continuous Flow Isotope Ratio Mass Spectrometer (CF-IRMS coupled with a Sercon SL elemental analyzer for simultaneous carbon-nitrogen-sulfur (NCS analysis.Results: A difference of about 1.781‰ in stable nitrogen isotope 15N/14N ratio was found between examined hepatoblastoma histological subtypes.Conclusions: The prognosis in liver tumors cases in children may be challenging particularly because of the lack of versatile methods of its evaluation. Isotope ratio mass spectrometry allows one to determine the difference between hepatoblastoma histological subtypes and clearly indicates the cases with the best outcome.

The influence of zirconia precursor/binding polymer mass ratio in the intermediate electrospun composite fibers on the phase transformation of final zirconia nanofibers

Energy Technology Data Exchange (ETDEWEB)

Rodaev, Vyacheslav V.; Zhigachev, Andrey O.; Korenkov, Viktor V.; Golovin, Yuri I. [Institute for Nanotechnology and Nanomaterials, Tambov State University, Internatsionalnaya Str. 33, 392000, Tambov (Russian Federation)

2016-09-15

Nanofibrous zirconia was fabricated by calcination of electrospun zirconium oxychloride/polyethylene oxide (PEO) composite fibers with different mass fraction of the components. ZrO{sub 2} nanofibers were characterized by scanning electron microscopy (SEM), nitrogen adsorption at 77 K, and X-ray diffractometry (XRD). It was revealed that increase in ZrOCl{sub 2}/PEO mass ratio above the threshold value significantly decreases tetragonal phase (t-ZrO{sub 2}) content and increases monoclinic phase (m-ZrO{sub 2}) content in final ceramic nanofibers. Distinct t-ZrO{sub 2} → m-ZrO{sub 2} transformation takes place when average ZrO{sub 2} grain size approaches to 30 nm. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

The mass angular scattering power method for determining the kinetic energies of clinical electron beams

International Nuclear Information System (INIS)

Blais, N.; Podgorsak, E.B.

1992-01-01

A method for determining the kinetic energy of clinical electron beams is described, based on the measurement in air of the spatial spread of a pencil electron beam which is produced from the broad clinical electron beam. As predicted by the Fermi-Eyges theory, the dose distribution measured in air on a plane, perpendicular to the incident direction of the initial pencil electron beam, is Gaussian. The square of its spatial spread is related to the mass angular scattering power which in turn is related to the kinetic energy of the electron beam. The measured spatial spread may thus be used to determine the mass angular scattering power, which is then used to determine the kinetic energy of the electron beam from the known relationship between mass angular scattering power and kinetic energy. Energies obtained with the mass angular scattering power method agree with those obtained with the electron range method. (author)

Measurement of the intensity ratio of Auger and conversion electrons for the electron capture decay of 125I

Science.gov (United States)

Alotiby, M.; Greguric, I.; Kibédi, T.; Lee, B. Q.; Roberts, M.; Stuchbery, A. E.; Tee, Pi; Tornyi, T.; Vos, M.

2018-03-01

Auger electrons emitted after nuclear decay have potential application in targeted cancer therapy. For this purpose it is important to know the Auger electron yield per nuclear decay. In this work we describe a measurement of the ratio of the number of conversion electrons (emitted as part of the nuclear decay process) to the number of Auger electrons (emitted as part of the atomic relaxation process after the nuclear decay) for the case of 125I. Results are compared with Monte-Carlo type simulations of the relaxation cascade using the BrIccEmis code. Our results indicate that for 125I the calculations based on rates from the Evaluated Atomic Data Library underestimate the K Auger yields by 20%.

Measurement of the intensity ratio of Auger and conversion electrons for the electron capture decay of 125I.

Science.gov (United States)

Alotiby, M; Greguric, I; Kibédi, T; Lee, B Q; Roberts, M; Stuchbery, A E; Tee, Pi; Tornyi, T; Vos, M

2018-03-21

Auger electrons emitted after nuclear decay have potential application in targeted cancer therapy. For this purpose it is important to know the Auger electron yield per nuclear decay. In this work we describe a measurement of the ratio of the number of conversion electrons (emitted as part of the nuclear decay process) to the number of Auger electrons (emitted as part of the atomic relaxation process after the nuclear decay) for the case of 125 I. Results are compared with Monte-Carlo type simulations of the relaxation cascade using the BrIccEmis code. Our results indicate that for 125 I the calculations based on rates from the Evaluated Atomic Data Library underestimate the K Auger yields by 20%.

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

Science.gov (United States)

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.

Galaxy and mass assembly (GAMA): the consistency of GAMA and WISE derived mass-to-light ratios

Science.gov (United States)

Kettlety, T.; Hesling, J.; Phillipps, S.; Bremer, M. N.; Cluver, M. E.; Taylor, E. N.; Bland-Hawthorn, J.; Brough, S.; De Propris, R.; Driver, S. P.; Holwerda, B. W.; Kelvin, L. S.; Sutherland, W.; Wright, A. H.

2018-01-01

Recent work has suggested that mid-IR wavelengths are optimal for estimating the mass-to-light ratios of stellar populations and hence the stellar masses of galaxies. We compare stellar masses deduced from spectral energy distribution (SED) models, fitted to multiwavelength optical-NIR photometry, to luminosities derived from WISE photometry in the W1 and W2 bands at 3.6 and 4.5 μm for non-star forming galaxies. The SED-derived masses for a carefully selected sample of low-redshift (z ≤ 0.15) passive galaxies agree with the prediction from stellar population synthesis models such that M*/LW1 ≃ 0.6 for all such galaxies, independent of other stellar population parameters. The small scatter between masses predicted from the optical SED and from the WISE measurements implies that random errors (as opposed to systematic ones such as the use of different initial mass functions) are smaller than previous, deliberately conservative, estimates for the SED fits. This test is subtly different from simultaneously fitting at a wide range of optical and mid-IR wavelengths, which may just generate a compromised fit: we are directly checking that the best-fitting model to the optical data generates an SED whose M*/LW1 is also consistent with separate mid-IR data. We confirm that for passive low-redshift galaxies a fixed M*/LW1 = 0.65 can generate masses at least as accurate as those obtained from more complex methods. Going beyond the mean value, in agreement with expectations from the models, we see a modest change in M*/LW1 with SED fitted stellar population age but an insignificant one with metallicity.

The ATLAS(3D) project - XX. Mass-size and mass-Sigma distributions of early-type galaxies : bulge fraction drives kinematics, mass-to-light ratio, molecular gas fraction and stellar initial mass function

NARCIS (Netherlands)

Cappellari, Michele; McDermid, Richard M.; Alatalo, Katherine; Blitz, Leo; Bois, Maxime; Bournaud, Frederic; Bureau, M.; Crocker, Alison F.; Davies, Roger L.; Davis, Timothy A.; de Zeeuw, P. T.; Duc, Pierre-Alain; Emsellem, Eric; Khochfar, Sadegh; Krajnovic, Davor; Kuntschner, Harald; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Scott, Nicholas; Serra, Paolo; Weijmans, Anne-Marie; Young, Lisa M.

2013-01-01

In the companion Paper XV of this series, we derive accurate total mass-to-light ratios (M/L)(JAM) approximate to (M/L)(r = R-e) within a sphere of radius r = R-e centred on the galaxy, as well as stellar (M/L)(stars) (with the dark matter removed) for the volume-limited and nearly mass-selected

Radial distributions of surface mass density and mass-to-luminosity ratio in spiral galaxies

Science.gov (United States)

Sofue, Yoshiaki

2018-03-01

We present radial profiles of the surface mass density (SMD) in spiral galaxies directly calculated using rotation curves of two approximations of flat-disk (SMD-F) and spherical mass distribution (SMD-S). The SMDs are combined with surface brightness using photometric data to derive radial variations of the mass-to-luminosity ratio (ML). It is found that the ML generally has a central peak or a plateau, and decreases to a local minimum at R ˜ 0.1-0.2 h, where R is the radius and h is the scale radius of optical disk. The ML, then, increases rapidly until ˜0.5 h, and is followed by gradual rise till ˜2 h, remaining at around ˜2 [M_{⊙} L^{-1}_{⊙}] in the w1 band (infrared λ3.4 μm) and ˜ 10 [M_⊙ L_⊙ ^{-1}] in the r band (λ6200-7500 Å). Beyond this radius, the ML increases steeply with approaching the observed edges at R ˜ 5 h, attaining to as high values as ˜20 in w1 and ˜ 10^2 [M_⊙ L_⊙ ^{-1}] in the r band, which are indicative of dominant dark matter. The general properties of the ML distributions will be useful for constraining cosmological formation models of spiral galaxies.

The correlation between HCN/H2O flux ratios and disk mass: evidence for protoplanet formation

Science.gov (United States)

Rose, Caitlin; Salyk, Colette

2017-01-01

We analyze hydrogen cyanide (HCN) and water vapor flux ratios in protoplanetary disks as a way to trace planet formation. Analyzing only disks in the Taurus molecular cloud, Najita et al. (2013) found a tentative correlation between protoplanetary disk mass and the HCN/H2O line flux ratio in Spitzer-IRS emission spectra. They interpret this correlation to be a consequence of more massive disks forming planetesimals more efficiently than smaller disks, as the formation of large planetesimals may lock up water ice in the cool outer disk region and prevent it from migrating, drying out the inner disk. The sequestering of water (and therefore oxygen) in the outer disk may also increase the carbon-to- oxygen ratio in the inner disk, leading to enhanced organic molecule (e.g. HCN) emission. To confirm this trend, we expand the Najita et al. sample by calculating HCN/H2O line flux ratios for 8 more sources with known disk masses from clusters besides Taurus. We find agreement with the Najita et al. trend, suggesting that this is a widespread phenomenon. In addition, we find HCN/H2O line flux ratios for 17 more sources that await disk mass measurements, which should become commonplace in the ALMA era. Finally, we investigate linear fits and outliers to this trend, and discuss possible causes.

A modified method of calculating the lateral build-up ratio for small electron fields

International Nuclear Information System (INIS)

Tyner, E; McCavana, P; McClean, B

2006-01-01

This note outlines an improved method of calculating dose per monitor unit values for small electron fields using Khan's lateral build-up ratio (LBR). This modified method obtains the LBR directly from the ratio of measured, surface normalized, electron beam percentage depth dose curves. The LBR calculated using this modified method more accurately accounts for the change in lateral scatter with decreasing field size. The LBR is used along with Khan's dose per monitor unit formula to calculate dose per monitor unit values for a set of small fields. These calculated dose per monitor unit values are compared to measured values to within 3.5% for all circular fields and electron energies examined. The modified method was further tested using a small triangular field. A maximum difference of 4.8% was found. (note)

Effect of B/Ti mass ratio on grain refining of low-titanium aluminum produced by electrolysis

International Nuclear Information System (INIS)

Wang Mingxing; Wang Sanjun; Liu Zhiyong; Liu Zhongxia; Song Tianfu; Zuo Xiurong

2006-01-01

The effect of B/Ti mass ratio on grain refining of the low-titanium aluminum produced by electrolysis was investigated by adding AlB master alloy to the melt of the low-titanium aluminum. The results show that the addition of titanium by electrolysis is an effective way of grain refining of aluminum, and addition of boron to the melt of the low-titanium aluminum can further increase the grain refining efficiency. And the best grain refining efficiency is obtained when the B/Ti mass ratio is 1:10. However, when the B/Ti mass ratio is 1:2.22 (the stoichiometric value for TiB 2 ), the grain refining efficiency vanishes almost completely. It means that all of the solute titanium atoms in the melt of the low-titanium aluminum react with boron atoms that come from AlB master alloy to form TiB 2 particles, and TiB 2 particles have not grain refining ability. The grain refining efficiency seems to increase with addition of more boron to the melt after the B/Ti mass ratio exceeds 1:2.22. But the grain refining efficiency is very poor, and similar to that of pure Al refined by AlB master alloy. It further shows that TiB 2 particles do not participate in grain refining, and that the excess boron atoms in the melt also cannot turn TiB 2 particles into the effective nuclei for aluminum as the solute titanium atoms do

Detector and front-end electronics of a fissile mass flow monitoring system

International Nuclear Information System (INIS)

Paulus, M.J.; Uckan, T.; Lenarduzzi, R.; Mullens, J.A.; Castleberry, K.N.; McMillan, D.E.; Mihalczo, J.T.

1997-01-01

A detector and front-end electronics unit with secure data transmission has been designed and implemented for a fissile mass flow monitoring system for fissile mass flow of gases and liquids in a pipe. The unit consists of 4 bismuth germanate (BGO) scintillation detectors, pulse-shaping and counting electronics, local temperature sensors, and on-board local area network nodes which locally acquire data and report to the master computer via a secure network link. The signal gain of the pulse-shaping circuitry and energy windows of the pulse-counting circuitry are periodicially self calibrated and self adjusted in situ using a characteristic line in the fissile material pulse height spectrum as a reference point to compensate for drift such as in the detector gain due to PM tube aging. The temperature- dependent signal amplitude variations due to the intrinsic temperature coefficients of the PM tube gain and BGO scintillation efficiency have been characterized and real-time gain corrections introduced. The detector and electronics design, measured intrinsic performance of the detectors and electronics, and the performance of the detector and electronics within the fissile mass flow monitoring system are described

Approximate Waveforms for Extreme-Mass-Ratio Inspirals: The Chimera Scheme

International Nuclear Information System (INIS)

Sopuerta, Carlos F; Yunes, Nicolás

2012-01-01

We describe a new kludge scheme to model the dynamics of generic extreme-mass-ratio inspirals (EMRIs; stellar compact objects spiraling into a spinning supermassive black hole) and their gravitational-wave emission. The Chimera scheme is a hybrid method that combines tools from different approximation techniques in General Relativity: (i) A multipolar, post-Minkowskian expansion for the far-zone metric perturbation (the gravitational waveforms) and for the local prescription of the self-force; (ii) a post-Newtonian expansion for the computation of the multipole moments in terms of the trajectories; and (iii) a BH perturbation theory expansion when treating the trajectories as a sequence of self-adjusting Kerr geodesies. The EMRI trajectory is made out of Kerr geodesic fragments joined via the method of osculating elements as dictated by the multipolar post-Minkowskian radiation-reaction prescription. We implemented the proper coordinate mapping between Boyer-Lindquist coordinates, associated with the Kerr geodesies, and harmonic coordinates, associated with the multipolar post-Minkowskian decomposition. The Chimera scheme is thus a combination of approximations that can be used to model generic inspirals of systems with extreme to intermediate mass ratios, and hence, it can provide valuable information for future space-based gravitational-wave observatories, like LISA, and even for advanced ground detectors. The local character in time of our multipolar post-Minkowskian self-force makes this scheme amenable to study the possible appearance of transient resonances in generic inspirals.

Accretion of satellites on to central galaxies in clusters: merger mass ratios and orbital parameters

Science.gov (United States)

Nipoti, Carlo; Giocoli, Carlo; Despali, Giulia

2018-05-01

We study the statistical properties of mergers between central and satellite galaxies in galaxy clusters in the redshift range 0 identify dark-matter haloes, we construct halo merger trees for different values of the overdensity Δc. While the virial overdensity definition allows us to probe the accretion of satellites at the cluster virial radius rvir, higher overdensities probe satellite mergers in the central region of the cluster, down to ≈0.06rvir, which can be considered a proxy for the accretion of satellite galaxies on to central galaxies. We find that the characteristic merger mass ratio increases for increasing values of Δc: more than 60 per cent of the mass accreted by central galaxies since z ≈ 1 comes from major mergers. The orbits of satellites accreting on to central galaxies tend to be more tangential and more bound than orbits of haloes accreting at the virial radius. The obtained distributions of merger mass ratios and orbital parameters are useful to model the evolution of the high-mass end of the galaxy scaling relations without resorting to hydrodynamic cosmological simulations.

Can the neutrino mass be measured using /sup 163/Ho electron capture

International Nuclear Information System (INIS)

Bennett, C.L.

1985-01-01

The safest limit on the neutrino mass comes from allowing the interference amplitude to be a free parameter in a fit to Springer's inner bremsstrahlung data while fixing the Q value to its upper limit based on the results of the relative capture rates from F. Hartmann's data. Since /sup 163/Ho was the most promising electron capture candidate for a neutrino mass detector, it is unlikely that electron capture will ever compete with tritium beta decay in terms of sensitivity to neutrino mass. The best fundamental thing that can be said is that the limit of the difference in the mass of the neutrino and its anti-particle is smaller in absolute value than for any other fermion anti-fermion pair

Detection of Enhanced Central Mass-to-light Ratios in Low-mass Early-type Galaxies: Evidence for Black Holes?

Science.gov (United States)

Pechetti, Renuka; Seth, Anil; Cappellari, Michele; McDermid, Richard; den Brok, Mark; Mieske, Steffen; Strader, Jay

2017-11-01

We present dynamical measurements of the central mass-to-light ratio (M/L) of a sample of 27 low-mass early-type {{ATLAS}}3{{D}} galaxies. We consider all {{ATLAS}}3{{D}} galaxies with 9.7 text{}}M/L{{s}} are higher than dynamical {\\text{}}M/L{{s}} derived at larger radii and stellar population estimates of the galaxy centers in ˜80% of galaxies, with a median enhancement of ˜14% and a statistical significance of 3.3σ. We show that the enhancement in the central M/L is best described either by the presence of black holes in these galaxies or by radial initial mass function variations. Assuming a black hole model, we derive black hole masses for the sample of galaxies. In two galaxies, NGC 4458 and NGC 4660, the data suggest significantly overmassive black holes, while in most others only upper limits are obtained. We also show that the level of M/L enhancements we see in these early-type galaxy nuclei are consistent with the larger enhancements seen in ultracompact dwarf galaxies (UCDs), supporting the scenario where massive UCDs are created by stripping galaxies of these masses.

Constructing binary black hole initial data with high mass ratios and spins

Science.gov (United States)

Ossokine, Serguei; Foucart, Francois; Pfeiffer, Harald; Szilagyi, Bela; Simulating Extreme Spacetimes Collaboration

2015-04-01

Binary black hole systems have now been successfully modelled in full numerical relativity by many groups. In order to explore high-mass-ratio (larger than 1:10), high-spin systems (above 0.9 of the maximal BH spin), we revisit the initial-data problem for binary black holes. The initial-data solver in the Spectral Einstein Code (SpEC) was not able to solve for such initial data reliably and robustly. I will present recent improvements to this solver, among them adaptive mesh refinement and control of motion of the center of mass of the binary, and will discuss the much larger region of parameter space this code can now address.

Creation of a predictive equation to estimate fat-free mass and the ratio of fat-free mass to skeletal size using morphometry in lean working farm dogs.

Science.gov (United States)

Leung, Y M; Cave, N J; Hodgson, B A S

2018-06-27

To develop an equation that accurately estimates fat-free mass (FFM) and the ratio of FFM to skeletal size or mass, using morphometric measurements in lean working farm dogs, and to examine the association between FFM derived from body condition score (BCS) and FFM measured using isotope dilution. Thirteen Huntaway and seven Heading working dogs from sheep and beef farms in the Waikato region of New Zealand were recruited based on BCS (BCS 4) using a nine-point scale. Bodyweight, BCS, and morphometric measurements (head length and circumference, body length, thoracic girth, and fore and hind limb length) were recorded for each dog, and body composition was measured using an isotopic dilution technique. A new variable using morphometric measurements, termed skeletal size, was created using principal component analysis. Models for predicting FFM, leanST (FFM minus skeletal mass) and ratios of FFM and leanST to skeletal size or mass were generated using multiple linear regression analysis. Mean FFM of the 20 dogs, measured by isotope dilution, was 22.1 (SD 4.4) kg and the percentage FFM of bodyweight was 87.0 (SD 5.0)%. Median BCS was 3.0 (min 1, max 6). Bodyweight, breed, age and skeletal size or mass were associated with measured FFM (pFFM and measured FFM (R 2 =0.96), and for the ratio of predicted FFM to skeletal size and measured values (R 2 =0.99). Correlation coefficients were higher for the ratio FFM and leanST to skeletal size than for ratios using skeletal mass. There was a positive correlation between BCS-derived fat mass as a percentage of bodyweight and fat mass percentage determined using isotope dilution (R 2 =0.65). As expected, the predictive equation was accurate in estimating FFM when tested on the same group of dogs used to develop the equation. The significance of breed, independent of skeletal size, in predicting FFM indicates that individual breed formulae may be required. Future studies that apply these equations on a greater population of

Analysis of [U-13C6]glucose in human plasma using liquid chromatography/isotope ratio mass spectrometry compared with two other mass spectrometry techniques

NARCIS (Netherlands)

Schierbeek, H.; Moerdijk-Poortvliet, T.C.W.; van den Akker, C.H.P.; te Braake, F.W.J.; Boschker, H.T.S.; van Goudoever, J.B.

2009-01-01

The use of stable isotope labelled glucose provides insight into glucose metabolism. The 13C-isotopic enrichment of glucose is usually measured by gas chromatography/mass spectrometry (GC/MS) or gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). However, in both techniques

The measurement of the isotope ratios and concentrations of zinc by thermal ionization mass spectrometry using double isotope dilution

International Nuclear Information System (INIS)

Deng Zhongguo

1994-01-01

The isotope ratios and concentrations of zinc are measured by silicagel-thermal ionization mass spectrometry using the double isotope spikers. The double isotope spikers ( 70 Zn and 67 Zn-enriched isotopes) are used to correct the isotope mass fractionation for the zinc isotope ratios, and to certify the zinc concentrations in the unknown samples. The zinc concentrations of these double isotope spikers are surveyed by a spiker made of pure (99.99%) natural zinc metal powder. The correcting factors (f a , f t and f n ) of the zinc isotope ratios in the spiked mixture, spike and unspiked samples for the isotope mass fractionation, and the spike-to-unspiked ratios (X r ) of the zinc isotope r in the spiked mixture samples can be obtained to solve the matrix equations by numerical approximation. The natural zinc isotope ratios are: 64 Zn/ 67 Zn = 11.8498, 66 Zn/ 67 Zn = 6.7977, 68 Zn/ 67 Zn = 4.5730 and 70 Zn/ 67 Zn = 0.1520. The uncertainties determined of the isotope ratios and concentrations of zinc are +- 0.16% and +-0.31%, respectively

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

Science.gov (United States)

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. Copyright © 2014 Elsevier Ltd. All rights reserved.

Experimental observations of electron-backscatter effects from high-atomic-number anodes in large-aspect-ratio, electron-beam diodes

Energy Technology Data Exchange (ETDEWEB)

Cooperstein, G; Mosher, D; Stephanakis, S J; Weber, B V; Young, F C [Naval Research Laboratory, Washington, DC (United States); Swanekamp, S B [JAYCOR, Vienna, VA (United States)

1997-12-31

Backscattered electrons from anodes with high-atomic-number substrates cause early-time anode-plasma formation from the surface layer leading to faster, more intense electron beam pinching, and lower diode impedance. A simple derivation of Child-Langmuir current from a thin hollow cathode shows the same dependence on the diode aspect ratio as critical current. Using this fact, it is shown that the diode voltage and current follow relativistic Child-Langmuir theory until the anode plasma is formed, and then follows critical current after the beam pinches. With thin hollow cathodes, electron beam pinching can be suppressed at low voltages (< 800 kV) even for high currents and high-atomic-number anodes. Electron beam pinching can also be suppressed at high voltages for low-atomic-number anodes as long as the electron current densities remain below the plasma turn-on threshold. (author). 8 figs., 2 refs.

Augmented kludge waveforms for detecting extreme-mass-ratio inspirals

Science.gov (United States)

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

2017-08-01

The extreme-mass-ratio inspirals (EMRIs) of stellar-mass compact objects into massive black holes are an important class of source for the future space-based gravitational-wave detector LISA. Detecting signals from EMRIs will require waveform models that are both accurate and computationally efficient. In this paper, we present the latest implementation of an augmented analytic kludge (AAK) model, publicly available at https://github.com/alvincjk/EMRI_Kludge_Suite as part of an EMRI waveform software suite. This version of the AAK model has improved accuracy compared to its predecessors, with two-month waveform overlaps against a more accurate fiducial model exceeding 0.97 for a generic range of sources; it also generates waveforms 5-15 times faster than the fiducial model. The AAK model is well suited for scoping out data analysis issues in the upcoming round of mock LISA data challenges. A simple analytic argument shows that it might even be viable for detecting EMRIs with LISA through a semicoherent template bank method, while the use of the original analytic kludge in the same approach will result in around 90% fewer detections.

The minimum mass of a charged spherically symmetric object in D dimensions, its implications for fundamental particles, and holography

International Nuclear Information System (INIS)

Burikham, Piyabut; Cheamsawat, Krai; Harko, Tiberiu; Lake, Matthew J.

2016-01-01

We obtain bounds for the minimum and maximum mass/radius ratio of a stable, charged, spherically symmetric compact object in a D-dimensional space-time in the framework of general relativity, and in the presence of dark energy. The total energy, including the gravitational component, and the stability of objects with minimum mass/radius ratio is also investigated. The minimum energy condition leads to a representation of the mass and radius of the charged objects with minimum mass/radius ratio in terms of the charge and vacuum energy only. As applied to the electron in the four-dimensional case, this procedure allows one to re-obtain the classical electron radius from purely general relativistic considerations. By combining the lower mass bound, in four space-time dimensions, with minimum length uncertainty relations (MLUR) motivated by quantum gravity, we obtain an alternative bound for the maximum charge/mass ratio of a stable, gravitating, charged quantum mechanical object, expressed in terms of fundamental constants. Evaluating this limit numerically, we obtain again the correct order of magnitude value for the charge/mass ratio of the electron, as required by the stability conditions. This suggests that, if the electron were either less massive (with the same charge) or if its charge were any higher (for fixed mass), a combination of electrostatic and dark energy repulsion would destabilize the Compton radius. In other words, the electron would blow itself apart. Our results suggest the existence of a deep connection between gravity, the presence of the cosmological constant, and the stability of fundamental particles. (orig.)

Precision electron-capture energy in {sup 202}Pb and its relevance for neutrino mass determination

Energy Technology Data Exchange (ETDEWEB)

Welker, A. [CERN, Geneva (Switzerland); Technische Universitaet Dresden, Dresden (Germany); Filianin, P. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Althubiti, N.A.S. [The University of Manchester, School of Physics and Astronomy, Manchester (United Kingdom); Atanasov, D.; Blaum, K.; Eliseev, S.; Kreim, S. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Cocolios, T.E. [The University of Manchester, School of Physics and Astronomy, Manchester (United Kingdom); KU Leuven, Instituut voor Kern- en Stralingsfysica, Leuven (Belgium); Herfurth, F.; Neidherr, D. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Lunney, D. [CSNSM-IN2P3-CNRS, Universite Paris-Sud, Orsay (France); Manea, V. [CERN, Geneva (Switzerland); Novikov, Yu. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Physics Faculty, St. Petersburg State University (Russian Federation); Rosenbusch, M.; Schweikhard, L.; Wienholtz, F. [Ernst-Moritz-Arndt-Universitaet, Institut fuer Physik, Greifswald (Germany); Wolf, R.N. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); The University of Sydney, ARC Centre of Excellence for Engineered Quantum Systems, Sydney (Australia); Zuber, K. [Technische Universitaet Dresden, Dresden (Germany)

2017-07-15

Within the framework of an extensive programme devoted to the search for alternative candidates for the neutrino mass determination, the atomic mass difference between {sup 202}Pb and {sup 202}Tl has been measured with the Penning trap mass spectrometer ISOLTRAP at the ISOLDE facility at CERN. The obtained value Q{sub EC} = 38.8(43) keV is three times more precise than the AME2012 value. While it will probably not lead to a replacement of {sup 163}Ho in modern experiments on the determination of the electron-neutrino mass, the electron capture in {sup 202}Pb would however allow a determination of the electron-neutrino mass on the few-eV level using a cryogenic micro-calorimeter. (orig.)

Evaluation of magnetization transfer ratio in ascites and pelvic cystic masses

Energy Technology Data Exchange (ETDEWEB)

Okada, Susumu [Nippon Medical School, Inba, Chiba (Japan). Chiba-Hokuso Hospital; Kato, Tomoyasu; Yamashita, Takashi [and others

1997-12-01

To investigate the feasibility of magnetization transfer contrast (MTC) in characterization of pelvic cystic masses and ascites, in vitro studies were performed. Cystic fluids were taken from operative specimens of ten ovarian cystic masses (five mucinous cystadenomas, one cystadenocarcinoma, two serous cystadenocarcinomas, two clear cell carcinomas) and three non-ovarian pelvic cysts (one paraovarian cyst, one pseudomyxoma peritonei, one pelvic abscess). Samples of ascitic flied were drawn by peritoneal puncture in twenty patients (thirteen with peritonitis carcinomatosa, five with liver dysfunction, two with renal dysfunction). Total protein content in ascitic fluids was measured. Magnetization transfer ratio (MTR) was calculated by the signal intensities under the gradient echo sequence with and without the application of off-resonance pulses. The relative signal intensities (RSI) relative to water in T{sub 1} and T{sub 2} weighted images were obtained using spin echo sequence. There was no correlation between histological type of pelvic mass and MTR and RSI. Good correlation (R{sup 2}=0.761) was obtained between MTR and protein content in ascitic fluids, whereas no correlation was noted between RSI and protein content in ascitic fluids. These results suggest that MTC is not useful in the characterization of pelvic masses but is applicable in the differentiation between exudative ascites and transudative ascites. (author)

Electron temperature measurement by a helium line intensity ratio method in helicon plasmas

International Nuclear Information System (INIS)

Boivin, R.F.; Kline, J.L.; Scime, E.E.

2001-01-01

Electron temperature measurements in helicon plasmas are difficult. The presence of intense rf fields in the plasma complicates the interpretation of Langmuir probe measurements. Furthermore, the non-negligible ion temperature in the plasma considerably shortens the lifetime of conventional Langmuir probes. A spectroscopic technique based on the relative intensities of neutral helium lines is used to measure the electron temperature in the HELIX (Hot hELicon eXperiment) plasma [P. A. Keiter et al., Phys. Plasmas 4, 2741 (1997)]. This nonintrusive diagnostic is based on the fact that electron impact excitation rate coefficients for helium singlet and triplet states differ as a function of the electron temperature. The different aspects related to the validity of this technique to measure the electron temperature in rf generated plasmas are discussed in this paper. At low plasma density (n e ≤10 11 cm -3 ), this diagnostic is believed to be very reliable since the population of the emitting level can be easily estimated with reasonable accuracy by assuming that all excitation originates from the ground state (steady-state corona model). At higher density, secondary processes (excitation transfer, excitation from metastable, cascading) become more important and a more complex collisional radiative model must be used to predict the electron temperature. In this work, different helium transitions are examined and a suitable transition pair is identified. For an electron temperature of 10 eV, the line ratio is measured as a function of plasma density and compared to values predicted by models. The measured line ratio function is in good agreement with theory and the data suggest that the excitation transfer is the dominant secondary process in high-density plasmas

Composite Fermi surface in the half-filled Landau level with anisotropic electron mass

Science.gov (United States)

Ippoliti, Matteo; Geraedts, Scott; Bhatt, Ravindra

We study the problem of interacting electrons in the lowest Landau level at half filling in the quantum Hall regime, when the electron dispersion is given by an anisotropic mass tensor. Based on experimental observations and theoretical arguments, the ground state of the system is expected to consist of composite Fermions filling an elliptical Fermi sea, with the anisotropy of the ellipse determined by the competing effects of the isotropic Coulomb interaction and anisotropic electron mass tensor. We test this idea quantitatively by using a numerical density matrix renormalization group method for quantum Hall systems on an infinitely long cylinder. Singularities in the structure factor allow us to map the Fermi surface of the composite Fermions. We compute the composite Fermi surface anisotropy for several values of the electron mass anisotropy which allow us to deduce the functional dependence of the former on the latter. This research was supported by Department of Energy Office of Basic Energy Sciences through Grant No. DE-SC0002140.

Angle resolved mass spectrometry of positive ions transmitted through high aspect ratio channels in a radio frequency discharge

NARCIS (Netherlands)

Stoffels - Adamowicz, E.; Stoffels, W.W.; Tachibana, K.; Imai, S.

1997-01-01

The behavior of positive ions in high aspect ratio structures, relevant to the reactive ion etching of deep trenches, has been studied by means of energy resolved mass spectrometry. High aspect ratio trenches are simulated by capillary plates with various aspect ratios. Angle resolved measurements

The origin of the mass, disk-to-halo mass ratio, and L-V relation of spiral galaxies

International Nuclear Information System (INIS)

Ashman, K.M.

1990-01-01

A model is presented in which spiral galaxies only form when t(c) is roughly equal to t(f) in a hot component of the protogalactic gas. This assumption, along with a disk stability criterion, predicts a range of spiral galaxy masses roughly consistent with observation. The nature of the cooling function for a primordial plasma implies that in less massive galaxies, more gas must fragment in the halo to preserve t(c) roughly equal to t(f). Consequently, less gas survives to form the disk, so that the disk-to-halo mass ratio increases with disk mass and hence galaxy luminosity. The canonical L proportional to V exp 4 relation can be reproduced by the model, and the apparent change in the slope of this relation also arises naturally. In the hierarchical clustering scenario, the model requires that all spirals formed at about the same epoch. These results support earlier claims that much of the dark matter observed in the universe is baryonic and probably formed during protogalactic collapse. 38 refs

A five-collector system for the simultaneous measurement of argon isotope ratios in a static mass spectrometer

Science.gov (United States)

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.

[Effect of elastic strain rate ratio method and virtual touch tissue quantification on the diagnosis of breast masses].

Science.gov (United States)

Gong, LiJie; He, Yan; Tian, Peng; Yan, Yan

2016-07-01

To determine the effect of elastic strain rate ratio method and virtual touch tissue quantification (VTQ) on the diagnosis of breast masses.
 Sixty female patients with breast cancer, who received surgical treatment in Daqing Oilfield General Hospital, were enrolled. All patients signed the informed consent paperwork and they were treated by routine ultrasound examination, compression elastography (CE) examination, and VTQ examination in turn. Strain ratio (SR) was checked by CE and shear wave velocity (SWV) value was measured by VTQ. The diagnostic values of different methods were evaluated by receiver operating characteristic (ROC) curves in the diagnosis of benign and malignant breast tumors.
 The maximum diameter and SWV value of the benign tumors were lower than those of the malignant tumors, and the SR ratio of benign masses was higher than that of malignant tumors (Pbreast mass than that used alone.

OGLE-2017-BLG-0173Lb: Low-mass-ratio Planet in a “Hollywood” Microlensing Event

Science.gov (United States)

Hwang, K.-H.; Udalski, A.; Shvartzvald, Y.; Ryu, Y.-H.; Albrow, M. D.; Chung, S.-J.; Gould, A.; Han, C.; Jung, Y. K.; Shin, I.-G.; Yee, J. C.; Zhu, W.; Cha, S.-M.; Kim, D.-J.; Kim, H.-W.; Kim, S.-L.; Lee, C.-U.; Lee, D.-J.; Lee, Y.; Park, B.-G.; Pogge, R. W.; KMTNet Collaboration; Skowron, J.; Mróz, P.; Poleski, R.; Kozłowski, S.; Soszyński, I.; Pietrukowicz, P.; Szymański, M. K.; Ulaczyk, K.; Pawlak, M.; OGLE Collaboration; Bryden, G.; Beichman, C.; Calchi Novati, S.; Gaudi, B. S.; Henderson, C. B.; Jacklin, S.; Penny, M. T.; UKIRT Microlensing Team

2018-01-01

We present microlensing planet OGLE-2017-BLG-0173Lb, with planet–host mass ratio of either q≃ 2.5× {10}-5 or q≃ 6.5× {10}-5, the lowest or among the lowest ever detected. The planetary perturbation is strongly detected, Δχ 2 ∼ 10000, because it arises from a bright (therefore, large) source passing over and enveloping the planetary caustic: a so-called “Hollywood” event. The factor ∼2.5 offset in q arises because of a previously unrecognized discrete degeneracy between Hollywood events in which the caustic is fully enveloped and those in which only one flank is enveloped, which we dub “Cannae” and “von Schlieffen,” respectively. This degeneracy is “accidental” in that it arises from gaps in the data. Nevertheless, the fact that it appears in a Δχ 2 = 10000 planetary anomaly is striking. We present a simple formalism to estimate the sensitivity of other Hollywood events to planets and show that they can lead to detections close to, but perhaps not quite reaching, the Earth/Sun mass ratio of 3× {10}-6. This formalism also enables an analytic understanding of the factor ∼2.5 offset in q between the Cannae and von Schlieffen solutions. The Bayesian estimates for the host mass, system distance, and planet–host projected separation are M={0.39}-0.24+0.40 {M}ȯ , {D}L={4.8}-1.8+1.5 {kpc}, and {a}\\perp =3.8+/- 1.6 {au}, respectively. The two estimates of the planet mass are {m}p={3.3}-2.1+3.8 {M}\\oplus and {m}p={8}-6+11 {M}\\oplus . The measured lens-source relative proper motion μ =6 {mas} {{yr}}-1 will permit imaging of the lens in about 15 years or at first light on adaptive-optics imagers on next-generation telescopes. These will allow one to measure the host mass but probably will not be able to resolve the planet–host mass-ratio degeneracy.

Studies in the determination of lead isotope ratios by inductively coupled plasma mass spectrometry

International Nuclear Information System (INIS)

Date, A.R.; Yuk Ying Cheung

1987-01-01

The application of ICP-MS to the determination of lead isotope ratios in geological materials is described. Data presented for a series of lead mineral concentrates are compared with reference values obtained by conventional solid source thermal ionisation mass spectrometry. The simultaneous determination of lead isotope ratios and trace elements is carried out in a rapid analysis mode. The application of an electrothermal vaporisation technique for small solution aliquots is described. Lead isotope ratio data for the United States Geological Survey standard reference silicate rock BCR-1, obtained without separation of lead from the matrix, are compared with previously published values obtained after separation. (author)

Simultaneous stable carbon isotopic analysis of wine glycerol and ethanol by liquid chromatography coupled to isotope ratio mass spectrometry.

Science.gov (United States)

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.

Binary star statistics: the mass ratio distribution for very wide systems

International Nuclear Information System (INIS)

Trimble, V.

1987-01-01

The distribution of mass ratios for a sample of common proper motion (CPM) binaries is determined and compared with that of 798 visual binaries (VB's) studied earlier, in hopes of answering the question: Can the member stars of these systems have been drawn at random from the normal initial mass function for single stars? The observed distributions peak strongly toward q = 1.0 for both kinds of systems, but less strongly for the CPM's than for the VB's. Due allowance having been made for assorted observational selection effects, it seems quite probable that the CPM's represent the observed part of a population drawn at random from the normal IMF, while the VB's are much more difficult to interpret that way and could, perhaps, result from a formation mechanism that somewhat favors sytems with roughly equal components. (author)

Derivation of electron density and temperature from (S II) and (O II) line intensity ratios

Energy Technology Data Exchange (ETDEWEB)

Canto, J; Meaburn, J; Theokas, A C [Manchester Univ. (UK). Dept of Astronomy; Elliott, K H [Anglo-Australian Observatory, Epping (Australia)

1980-12-01

Line intensity ratios for (S II) and (O II) due to collisional de-excitation are briefly discussed. Comparison is made between various reaction rate parameters presented by separate investigators. Included are observations of ratios obtained from the Orion nebula which experimentally confirm the reaction rates of Pradhan as best representing the observed distribution of these ratios. (O II) and (S II) contour plots are also presented, which allow effective electron temperatures and densities to be estimated from pairs of line ratios.

A hybrid gyrokinetic ion and isothermal electron fluid code for astrophysical plasma

Science.gov (United States)

Kawazura, Y.; Barnes, M.

2018-05-01

This paper describes a new code for simulating astrophysical plasmas that solves a hybrid model composed of gyrokinetic ions (GKI) and an isothermal electron fluid (ITEF) Schekochihin et al. (2009) [9]. This model captures ion kinetic effects that are important near the ion gyro-radius scale while electron kinetic effects are ordered out by an electron-ion mass ratio expansion. The code is developed by incorporating the ITEF approximation into AstroGK, an Eulerian δf gyrokinetics code specialized to a slab geometry Numata et al. (2010) [41]. The new code treats the linear terms in the ITEF equations implicitly while the nonlinear terms are treated explicitly. We show linear and nonlinear benchmark tests to prove the validity and applicability of the simulation code. Since the fast electron timescale is eliminated by the mass ratio expansion, the Courant-Friedrichs-Lewy condition is much less restrictive than in full gyrokinetic codes; the present hybrid code runs ∼ 2√{mi /me } ∼ 100 times faster than AstroGK with a single ion species and kinetic electrons where mi /me is the ion-electron mass ratio. The improvement of the computational time makes it feasible to execute ion scale gyrokinetic simulations with a high velocity space resolution and to run multiple simulations to determine the dependence of turbulent dynamics on parameters such as electron-ion temperature ratio and plasma beta.

Electron response and e/h ratio of ATLAS barrel hadron prototype calorimeter

International Nuclear Information System (INIS)

Budagov, Yu.A.; Vinogradov, V.B.; Arkadov, V.V.; Karapetyan, G.V.

1995-01-01

The detailed information about electron response, electron energy resolution and e/h ratio as a function of incident energy E, impact point Z and incidence angle Θ of ATLAS iron-scintillator hadron prototype calorimeter with longitudinal tile configuration is presented. These results are based on electron and pion beams data of E=20, 50, 100, 150, 300 GeV at Θ=10 deg, 20 deg, 30 deg, which were obtained during test beam period in July 1995. The obtained calibration constant is used for muon response converting from pC to GeV. The results are compared with existing experimental data and with some Monte Carlo calculations. For some E, Θ, Z values the compensation (e/h=1) is observed. 23 refs., 18 figs., 9 tabs

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

Science.gov (United States)

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

2014-07-01

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? 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. 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. 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. 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. 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 HOMA-IR and HOMA-%β-cell values, than controls. In models adjusted for WHR and free testosterone and diagnostic groups, fasting insulin levels, HOMA-IR, and

Proceedings of the 9th workshop on the mass of the electron neutrino

International Nuclear Information System (INIS)

Yasumi, Shinjiro

1984-03-01

The 9th workshop on the mass of electron neutrinos was held at KEK, Japan. The experimental studies concerning the M-shell of Dy atoms for the measurement of the mass of electron neutrinos were presented at the workshop. The reports included in this proceedings concern windowless Si(Li) detectors, the irradiation technique to make Ho-163 radioactive sources, high purity Ho-163 sources, the M X-ray spectra of rare earth atoms, the study on the M-shell of Dy atoms by using monochromatic X-ray from the KEK PF (Photon Factory), the absolute measurement of photon beam flux, the angular distribution of M X-ray accompanying the photoelectric effect caused by linearly polarized photons, the X-ray spectrum around the 5p to 3s peak accompanying the decay of Ho-163, and the data of nuclear matrix elements of the electron capture decay of Ho-163. The reports presented at the previous workshop are also included in this proceedings. They concern the theoretical calculation of the M X-ray spectrum of Dy, the mass measurement of electron neutrinos, the X-ray spectrum of Ho-163 sources, the amount of Dy-164 contained in Ho-163 samples, and the isotope dilution mass spectrometry. (Kato, T.)

Highly Manufacturable Deep (Sub-Millimeter) Etching Enabled High Aspect Ratio Complex Geometry Lego-Like Silicon Electronics

KAUST Repository

Ghoneim, Mohamed T.

2017-02-01

A highly manufacturable deep reactive ion etching based process involving a hybrid soft/hard mask process technology shows high aspect ratio complex geometry Lego-like silicon electronics formation enabling free-form (physically flexible, stretchable, and reconfigurable) electronic systems.

Detection strategies for extreme mass ratio inspirals

International Nuclear Information System (INIS)

Cornish, Neil J

2011-01-01

The capture of compact stellar remnants by galactic black holes provides a unique laboratory for exploring the near-horizon geometry of the Kerr spacetime, or possible departures from general relativity if the central cores prove not to be black holes. The gravitational radiation produced by these extreme mass ratio inspirals (EMRIs) encodes a detailed map of the black hole geometry, and the detection and characterization of these signals is a major scientific goal for the LISA mission. The waveforms produced are very complex, and the signals need to be coherently tracked for tens of thousands of cycles to produce a detection, making EMRI signals one of the most challenging data analysis problems in all of gravitational wave astronomy. Estimates for the number of templates required to perform an exhaustive grid-based matched-filter search for these signals are astronomically large, and far out of reach of current computational resources. Here I describe an alternative approach that employs a hybrid between genetic algorithms and Markov chain Monte Carlo techniques, along with several time-saving techniques for computing the likelihood function. This approach has proven effective at the blind extraction of relatively weak EMRI signals from simulated LISA data sets.

A spherical electron cloud hopping model for studying product branching ratios of dissociative recombination.

Science.gov (United States)

Yu, Hua-Gen

2008-05-21

A spherical electron cloud hopping (SECH) model is proposed to study the product branching ratios of dissociative recombination (DR) of polyatomic systems. In this model, the fast electron-captured process is treated as an instantaneous hopping of a cloud of uniform spherical fractional point charges onto a target M+q ion (or molecule). The sum of point charges (-1) simulates the incident electron. The sphere radius is determined by a critical distance (Rc eM) between the incoming electron (e-) and the target, at which the potential energy of the e(-)-M+q system is equal to that of the electron-captured molecule M+q(-1) in a symmetry-allowed electronic state with the same structure as M(+q). During the hopping procedure, the excess energies of electron association reaction are dispersed in the kinetic energies of M+q(-1) atoms to conserve total energy. The kinetic energies are adjusted by linearly adding atomic momenta in the direction of driving forces induced by the scattering electron. The nuclear dynamics of the resultant M+q(-1) molecule are studied by using a direct ab initio dynamics method on the adiabatic potential energy surface of M+q(-1), or together with extra adiabatic surface(s) of M+q(-1). For the latter case, the "fewest switches" surface hopping algorithm of Tully was adapted to deal with the nonadiabaticity in trajectory propagations. The SECH model has been applied to study the DR of both CH+ and H3O+(H2O)2. The theoretical results are consistent with the experiment. It was found that water molecules play an important role in determining the product branching ratios of the molecular cluster ion.

Stopping-power ratios for dosimetry

International Nuclear Information System (INIS)

Andreo, P.

1988-01-01

The determination of the absorbed dose at a specified location in a medium irradiated with an electron or photon beam normally consists of two steps: (1) the determination of the mean absorbed dose to a detector by using a calibration factor or performing an absolute measurement, (2) the determination of the absorbed dose to the medium at the point of interest by calculations based on the knowledge of the absorbed dose to the detector and the different stopping and scattering properties of the medium and the detector material. When the influence of the detector is so small that the electron fluence in the medium is not modified, the ratio of the mass collision stopping power of the two materials accounts for the differences in energy deposition, and provides a conversion factor to relate the absorbed dose in both materials. Today, all national and international dosimetry protocols and codes of practice are based on such procedures, and the user easily can carry out these steps using tabulated data to convert a measured quantity to absorbed dose in the irradiated medium at the location of interest. Effects due to the spatial extension of the detector are taken into account using perturbation correction factors. The Monte Carlo method has become the most common and powerful calculational technique for determining the electron fluence (energy spectra) under different irradiation conditions. Cavity theory is then used to calculate stopping-power ratios. In this chapter, the different steps needed to evaluate s-ratios will be considered, emphasizing the different types of cavity-theory integrals and the Monte Carlo techniques used to derive the necessary electron spectra in the range of energies commonly used in radiation dosimetry, i.e., photon and electron beams with energies up to 50 MeV

ELECTRON ACCELERATIONS AT HIGH MACH NUMBER SHOCKS: TWO-DIMENSIONAL PARTICLE-IN-CELL SIMULATIONS IN VARIOUS PARAMETER REGIMES

Energy Technology Data Exchange (ETDEWEB)

Matsumoto, Yosuke [Department of Physics, Chiba University, Yayoi-cho 1-33, Inage-ku, Chiba 263-8522 (Japan); Amano, Takanobu; Hoshino, Masahiro, E-mail: ymatumot@astro.s.chiba-u.ac.jp [Department of Earth and Planetary Science, University of Tokyo, Hongo 1-33, Bunkyo-ku, Tokyo 113-0033 (Japan)

2012-08-20

Electron accelerations at high Mach number collisionless shocks are investigated by means of two-dimensional electromagnetic particle-in-cell simulations with various Alfven Mach numbers, ion-to-electron mass ratios, and the upstream electron {beta}{sub e} (the ratio of the thermal pressure to the magnetic pressure). We find electrons are effectively accelerated at a super-high Mach number shock (M{sub A} {approx} 30) with a mass ratio of M/m = 100 and {beta}{sub e} = 0.5. The electron shock surfing acceleration is an effective mechanism for accelerating the particles toward the relativistic regime even in two dimensions with a large mass ratio. Buneman instability excited at the leading edge of the foot in the super-high Mach number shock results in a coherent electrostatic potential structure. While multi-dimensionality allows the electrons to escape from the trapping region, they can interact with the strong electrostatic field several times. Simulation runs in various parameter regimes indicate that the electron shock surfing acceleration is an effective mechanism for producing relativistic particles in extremely high Mach number shocks in supernova remnants, provided that the upstream electron temperature is reasonably low.

Ratio of muscle mass to fat mass assessed by bioelectrical impedance analysis is significantly correlated with liver fat accumulation in patients with type 2 diabetes mellitus.

Science.gov (United States)

Kurinami, Noboru; Sugiyama, Seigo; Morita, Ayami; Yoshida, Akira; Hieshima, Kunio; Miyamoto, Fumio; Kajiwara, Keizo; Jinnouch, Katsunori; Jinnouchi, Tomio; Jinnouchi, Hideaki

2018-05-01

Obesity and ectopic fat accumulation are important conditions of type 2 diabetes mellitus (T2DM). Our aim was to determine whether bioelectrical impedance body composition analysis combined with blood test results could estimate liver ectopic fat accumulation in patients with treatment-naïve T2DM. Subjects were 119 untreated T2DM patients. Computed tomography scans were performed to calculate the liver to spleen attenuation ratio (L/S ratio) as a measure of liver fat accumulation, with excess liver fat accumulation defined as an L/S ratio analysis using InBody770. The Nagelkerke R 2 test showed that the muscle mass/fat mass ratio (muscle/fat ratio) was the most suitable variable among anthropometric factors and body component indexes for estimating liver fat accumulation. The muscle/fat ratio was significantly correlated with the L/S ratio (ρ = 0.4386, P analysis showed that the muscle/fat ratio (odds ratio 0.40, 95% confidence interval 0.22-0.73, P ratio 1.06, 95% confidence interval 1.02-1.10, P analysis, the cutoff value of the muscle/fat ratio for excess liver fat accumulation was 2.34. In patients with treatment-naïve T2DM, the muscle/fat ratio and ALT are useful for estimating the presence of excess liver fat accumulation in daily clinical practice. Copyright © 2018. Published by Elsevier B.V.

Evaluation of electrical impedance ratio measurements in accuracy of electronic apex locators.

Science.gov (United States)

Kim, Pil-Jong; Kim, Hong-Gee; Cho, Byeong-Hoon

2015-05-01

The aim of this paper was evaluating the ratios of electrical impedance measurements reported in previous studies through a correlation analysis in order to explicit it as the contributing factor to the accuracy of electronic apex locator (EAL). The literature regarding electrical property measurements of EALs was screened using Medline and Embase. All data acquired were plotted to identify correlations between impedance and log-scaled frequency. The accuracy of the impedance ratio method used to detect the apical constriction (APC) in most EALs was evaluated using linear ramp function fitting. Changes of impedance ratios for various frequencies were evaluated for a variety of file positions. Among the ten papers selected in the search process, the first-order equations between log-scaled frequency and impedance were in the negative direction. When the model for the ratios was assumed to be a linear ramp function, the ratio values decreased if the file went deeper and the average ratio values of the left and right horizontal zones were significantly different in 8 out of 9 studies. The APC was located within the interval of linear relation between the left and right horizontal zones of the linear ramp model. Using the ratio method, the APC was located within a linear interval. Therefore, using the impedance ratio between electrical impedance measurements at different frequencies was a robust method for detection of the APC.

Synthesis and characterization of Fe_3O_4 nanoparticles stabilized by polyvinylpyrrolidone / polyethylene glycol with variable mass ratios

International Nuclear Information System (INIS)

Silva, F.A.S. da; Campos, M.F. de; Rojas, E. E.G.

2014-01-01

Magnetic nanoparticles are devices able to optimize cancer treatments. In particular, magnetite nanoparticles are very effective in producing heat to cause lysis of tumor cells. However, in order that nanoparticles are internalized without causing damage to body they must be coated by biocompatible material. In this work, Fe_3O_4 nanoparticles were coated by a polymer blend: polyethylene glycol / polyvinylpyrrolidone. Some variations in mass ratio of polymer mixture were made. The effect of varying mass ratio in polymers was investigated. Samples were characterized by X-ray diffraction and Rietveld analysis. Moreover, hysteresis curves were analyzed. The results indicate good agreement between mass proportions used and physical and magnetic properties of nanocomposite. (author)

Isotopic ratio measurement using a double focusing magnetic sector mass analyser with an inductively coupled plasma as an ion source

International Nuclear Information System (INIS)

Walder, A.J.; Freedman, P.A.

1992-01-01

An inductively coupled plasma source was coupled to a magnetic sector mass analyser equipped with seven Faraday detectors. An electrostatic filter located between the plasma source and the magnetic sector was used to create a double focusing system. Isotopic ratio measurements of uranium and lead standards revealed levels of internal and external precision comparable to those obtained using thermal inonization mass spectrometry. An external precision of 0.014% was obtained from the 235 U: 238 U measurement of six samples of a National Bureau of Standards (NBS) Standard Reference Material (SRM) U-500, while an RSD of 0.022% was obtained from the 206 Pb: 204 Pb measurement of six samples of NBS SRM Pb-981. Measured isotopic ratios deviated from the NBS value by approximately 0.9% per atomic mass unit. This deviation approximates to a linear function of mass bias and can therefore be corrected for by the analysis of standards. The analysis of NBS SRM Sr-987 revealed superior levels of internal and external precision. The normalization of the 87 Sr: 86 Sr ratio to the 86 Sr: 88 Sr ratio reduced the RSD to approximately 0.008%. The measured ratio was within 0.01% of the NBS value and the day-to-day reproducibility was consistent within one standard deviation. (author)

Phenomenological approach to the modelling of elliptical galaxies: The problem of the mass-to-light ratio

Directory of Open Access Journals (Sweden)

Samurović S.

2007-01-01

Full Text Available In this paper the problem of the phenomenological modelling of elliptical galaxies using various available observational data is presented. Recently, Tortora, Cardona and Piedipalumbo (2007 suggested a double power law expression for the global cumulative mass-to-light ratio of elliptical galaxies. We tested their expression on a sample of ellipticals for which we have the estimates of the mass-to-light ratio beyond ~ 3 effective radii, a region where dark matter is expected to play an important dynamical role. We found that, for all the galaxies in our sample, we have α + β > 0, but that this does not necessarily mean a high dark matter content. The galaxies with higher mass (and higher dark matter content also have higher value of α+β. It was also shown that there is an indication that the galaxies with higher value of the effective radius also have higher dark matter content. .

Electrons and kaons in charmed particle decays

International Nuclear Information System (INIS)

Feller, J.M.

1979-05-01

Inclusive studies of the electron content, kaon content, and associated electron-kaon content of the decays of D mesons and other charmed particles produced in electron-positron annihilation are presented. At the psi(3772) resonance the following inclusive branching ratios for D meson decays to charged kaons were measured. Also at the psi(3772) resonance the average semileptonic branching ratio for D 0 and D + decays to electrons has been measured to be .076 +- .028. The average semileptonic branching ratio of charmed particles produced in e + e - annihilation at center-of-mass energies from 3.9 to 7.4 GeV is found to be equal within errors to that of the D's. At all energies the electron momentum spectra are consistent with a combination of the decays D → Ke nu and D → K*e nu. 84 references

Evaluation of electrical impedance ratio measurements in accuracy of electronic apex locators

Directory of Open Access Journals (Sweden)

Pil-Jong Kim

2015-05-01

Full Text Available Objectives The aim of this paper was evaluating the ratios of electrical impedance measurements reported in previous studies through a correlation analysis in order to explicit it as the contributing factor to the accuracy of electronic apex locator (EAL. Materials and Methods The literature regarding electrical property measurements of EALs was screened using Medline and Embase. All data acquired were plotted to identify correlations between impedance and log-scaled frequency. The accuracy of the impedance ratio method used to detect the apical constriction (APC in most EALs was evaluated using linear ramp function fitting. Changes of impedance ratios for various frequencies were evaluated for a variety of file positions. Results Among the ten papers selected in the search process, the first-order equations between log-scaled frequency and impedance were in the negative direction. When the model for the ratios was assumed to be a linear ramp function, the ratio values decreased if the file went deeper and the average ratio values of the left and right horizontal zones were significantly different in 8 out of 9 studies. The APC was located within the interval of linear relation between the left and right horizontal zones of the linear ramp model. Conclusions Using the ratio method, the APC was located within a linear interval. Therefore, using the impedance ratio between electrical impedance measurements at different frequencies was a robust method for detection of the APC.

Interactions of electrons with biologically important molecules

International Nuclear Information System (INIS)

Pisklova, K.; Papp, P.; Stano, M.

2012-01-01

For the study of interactions of low-energy electrons with the molecules in the gas phase, the authors used electron-molecule cross-beam apparatus. The experiment is carried out in high vacuum, where molecules of the tested compound are inducted through a capillary. For purposes of this experiment the sample was electrically heated to 180 Deg C., giving a bundle of GlyGly molecules into the gas phase. The resulting signals can be evaluated in two different modes: mass spectrum - at continuous electron energy (e.g. 100 eV) they obtained the signal of intensity of the ions according to their mass to charge ratio; ionization and resonance spectra - for selected ion mass when the authors received the signal of intensity of the ions, depending on the energy of interacting electron.

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

International Nuclear Information System (INIS)

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

η→3π: Study of the Dalitz Plot and Extraction of the Quark Mass Ratio Q.

Science.gov (United States)

Colangelo, Gilberto; Lanz, Stefan; Leutwyler, Heinrich; Passemar, Emilie

2017-01-13

The η→3π amplitude is sensitive to the quark mass difference m_{u}-m_{d} and offers a unique way to determine the quark mass ratio Q^{2}≡(m_{s}^{2}-m_{ud}^{2})/(m_{d}^{2}-m_{u}^{2}) from experiment. We calculate the amplitude dispersively and fit the KLOE Collaboration data on the charged mode, varying the subtraction constants in the range allowed by chiral perturbation theory. The parameter-free predictions obtained for the neutral Dalitz plot and the neutral-to-charged branching ratio are in excellent agreement with experiment. Our representation of the transition amplitude implies Q=22.0±0.7.

Influence of air mass source sector on variations in CO2 mixing ratio at a boreal site in northern Finland

International Nuclear Information System (INIS)

Aalto, T.; Hatakka, J.; Viisanen, Y.

2003-01-01

CO 2 mixing ratio in air masses coming from different source sectors was studied at Pallas measurement station in Lapland. Source sectors were defined using back trajectories and wind direction measurements. Air masses from the North and West sectors showed an annual variation of 17 ppm, possibly affected by a long range transported marine air. A larger variation of 20 ppm was observed in air masses from the more continental South and East sectors. During late autumn mixing ratios in air masses from the South sector were high in comparison with the other sectors. Different methods for a source sector definition were considered for the site, located in a contoured terrain. 52%-73% of wind direction-based source sector definitions agreed with trajectory- based definitions. However, the number of cases with reliable sector definitions may remain low when considering all observations. Different definition methods can cause differences of the order of 1 ppm in sectorially selected monthly mean CO 2 mixing ratios. (orig.)

Coulomb drag in electron-hole bilayer: Mass-asymmetry and exchange correlation effects

Science.gov (United States)

Arora, Priya; Singh, Gurvinder; Moudgil, R. K.

2018-04-01

Motivated by a recent experiment by Zheng et al. [App. Phys. Lett. 108, 062102 (2016)] on coulomb drag in electron-hole and hole-hole bilayers based on GaAs/AlGaAs semiconductor heterostructure, we investigate theoretically the influence of mass-asymmetry and temperature-dependence of correlations on the drag rate. The correlation effects are dealt with using the Vignale-Singwi effective inter-layer interaction model which includes correlations through local-field corrections to the bare coulomb interactions. However, in this work, we have incorporated only the intra-layer correlations using the temperature-dependent Hubbard approximation. Our results display a reasonably good agreement with the experimental data. However, it is crucial to include both the electron-hole mass-asymmetry and temperature-dependence of correlations. Mass-asymmetry and correlations are found to result in a substantial enhancement of drag resistivity.

Mixed-mode chromatography/isotope ratio mass spectrometry.

Science.gov (United States)

McCullagh, James S O

2010-03-15

Liquid chromatography coupled to molecular mass spectrometry (LC/MS) has been a standard technique since the early 1970s but liquid chromatography coupled to high-precision isotope ratio mass spectrometry (LC/IRMS) has only been available commercially since 2004. This development has, for the first time, enabled natural abundance and low enrichment delta(13)C measurements to be applied to individual analytes in aqueous mixtures creating new opportunities for IRMS applications, particularly for the isotopic study of biological molecules. A growing number of applications have been published in a range of areas including amino acid metabolism, carbohydrates studies, quantification of cellular and plasma metabolites, dietary tracer and nucleic acid studies. There is strong potential to extend these to new compounds and complex matrices but several challenges face the development of LC/IRMS methods. To achieve accurate isotopic measurements, HPLC separations must provide baseline-resolution between analyte peaks; however, the design of current liquid interfaces places severe restrictions on compatible flow rates and in particular mobile phase compositions. These create a significant challenge on which reports associated with LC/IRMS have not previously focused. Accordingly, this paper will address aspects of chromatography in the context of LC/IRMS, in particular focusing on mixed-mode separations and their benefits in light of these restrictions. It aims to provide an overview of mixed-mode stationary phases and of ways to improve high aqueous separations through manipulation of parameters such as column length, temperature and mobile phase pH. The results of several practical experiments are given using proteogenic amino acids and nucleosides both of which are of noted importance in the LC/IRMS literature. This communication aims to demonstrate that mixed-mode stationary phases provide a flexible approach given the constraints of LC/IRMS interface design and acts as a

Mass spectrometric measurement of urinary kynurenine-to-tryptophan ratio in children with and without urinary tract infection.

Science.gov (United States)

Yarbrough, Melanie L; Briden, Kelleigh E; Mitsios, John V; Weindel, Annette L; Terrill, Cindy M; Hunstad, David A; Dietzen, Dennis J

2018-04-19

Indoleamine-2,3-dioxygenase (IDO) catalyzes the first step of tryptophan (Trp) catabolism, yielding kynurenine (Kyn) metabolites. The kynurenine-to-tryptophan (K/T) ratio is used as a surrogate for biological IDO enzyme activity. IDO expression is increased during Escherichia coli urinary tract infection (UTI). Thus, our objective was to develop a method for measurement of Kyn/Trp ratio in human blood and urine and evaluate its use as a biomarker of UTI. A mass spectrometric method was developed to measure Trp and Kyn in serum and urine specimens. The method was applied to clinical urine specimens from symptomatic pediatric patients with laboratory-confirmed UTI or other acute conditions and from healthy controls. The liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was linear to 500 μmol/L for both Trp and Kyn. Imprecision ranged from 5 to 15% for Trp and 6-20% for Kyn. Analytical recoveries of Trp and Kyn ranged from 96 to 119% in serum and 90-97% in urine. No correlation was found between the K/T ratio and circulating IDO mass (r = 0.110) in serum. Urinary Kyn and Trp in the pediatric test cohort demonstrated elevations in the K/T ratio in symptomatic patients with UTI (median 13.08) and without UTI (median 14.38) compared to healthy controls (median 4.93; p < 0.001 for both comparisons). No significant difference in K/T ratio was noted between symptomatic patients with and without UTI (p = 0.84). Measurement of Trp and Kyn by LC-MS/MS is accurate and precise in serum and urine specimens. While urinary K/T ratio is not a specific biomarker for UTI, it may represent a general indicator of a systemic inflammatory process. Copyright © 2018 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Highly Manufacturable Deep (Sub-Millimeter) Etching Enabled High Aspect Ratio Complex Geometry Lego-Like Silicon Electronics.

Science.gov (United States)

Ghoneim, Mohamed Tarek; Hussain, Muhammad Mustafa

2017-04-01

A highly manufacturable deep reactive ion etching based process involving a hybrid soft/hard mask process technology shows high aspect ratio complex geometry Lego-like silicon electronics formation enabling free-form (physically flexible, stretchable, and reconfigurable) electronic systems. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Search for Excited Electrons at HERA

CERN Document Server

Adloff, C.; Andrieu, B.; Anthonis, T.; Astvatsatourov, A.; Babaev, A.; Bahr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Baumgartner, S.; Becker, J.; Beckingham, M.; Beglarian, A.; Behnke, O.; Belousov, A.; Berger, C.; Berndt, T.; Bizot, J.C.; Bohme, J.; Boudry, V.; Braunschweig, W.; Brisson, V.; Broker, H.B.; Brown, D.P.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Burrage, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Caron, S.; Cassol-Brunner, F.; Clarke, D.; Collard, C.; Contreras, J.G.; Coppens, Y.R.; Coughlan, J.A.; Cousinou, M.C.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; Davidsson, M.; Delcourt, B.; Delerue, N.; Demirchyan, R.; De Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dingfelder, J.; Dixon, P.; Dodonov, V.; Dowell, J.D.; Droutskoi, A.; Dubak, A.; Duprel, C.; Eckerlin, Guenter; Eckstein, D.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eisenhandler, E.; Ellerbrock, M.; Elsen, E.; Erdmann, M.; Erdmann, W.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Ferron, S.; Fleischer, M.; Fleischmann, P.; Fleming, Y.H.; Flugge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Franke, G.; Frising, G.; Gabathuler, E.; Gabathuler, K.; Garvey, J.; Gassner, J.; Gayler, Joerg; Gerhards, R.; Gerlich, C.; Ghazaryan, Samvel; Goerlich, L.; Gogitidze, N.; Grab, C.; Grabski, V.; Grassler, H.; Greenshaw, T.; Grindhammer, Guenter; Hadig, T.; Haidt, D.; Hajduk, L.; Haller, J.; Heinemann, B.; Heinzelmann, G.; Henderson, R.C.W.; Hengstmann, S.; Henschel, H.; Heremans, R.; Herrera, G.; Herynek, I.; Hildebrandt, M.; Hilgers, M.; Hiller, K.H.; Hladky, J.; Hoting, P.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hurling, S.; Ibbotson, M.; Issever, C.; Jacquet, M.; Jaffre, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, C.; Johnson, D.P.; Jones, M.A.S.; Jung, H.; Kant, D.; Kapichine, M.; Karlsson, M.; Karschnick, O.; Katzy, J.; Keil, F.; Keller, N.; Kennedy, J.; Kenyon, I.R.; Kiesling, Christian M.; Kjellberg, P.; Klein, M.; Kleinwort, C.; Kluge, T.; Knies, G.; Koblitz, B.; Kolya, S.D.; Korbel, V.; Kostka, P.; Kotelnikov, S.K.; Koutouev, R.; Koutov, A.; Kroseberg, J.; Kruger, K.; Kuhr, T.; Lamb, D.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Laycock, P.; Lebailly, E.; Lebedev, A.; Leissner, B.; Lemrani, R.; Lendermann, V.; Levonian, S.; List, B.; Lobodzinska, E.; Lobodzinski, B.; Loginov, A.; Loktionova, N.; Lubimov, V.; Luders, S.; Luke, D.; Lytkin, L.; Malden, N.; Malinovski, E.; Mangano, S.; Maracek, R.; Marage, P.; Marks, J.; Marshall, R.; Martyn, H.U.; Martyniak, J.; Maxfield, S.J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Michine, S.; Mikocki, S.; Milstead, D.; Mohrdieck, S.; Mondragon, M.N.; Moreau, F.; Morozov, A.; Morris, J.V.; Muller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, T.; Newman, Paul R.; Niebergall, F.; Niebuhr, C.; Nix, O.; Nowak, G.; Nozicka, M.; Olivier, B.; Olsson, J.E.; Ozerov, D.; Panassik, V.; Pascaud, C.; Patel, G.D.; Peez, M.; Perez, E.; Petrukhin, A.; Phillips, J.P.; Pitzl, D.; Poschl, R.; Potachnikova, I.; Povh, B.; Rauschenberger, J.; Reimer, P.; Reisert, B.; Risler, C.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rusakov, S.; Rybicki, K.; Sankey, D.P.C.; Schatzel, S.; Scheins, J.; Schilling, F.P.; Schleper, P.; Schmidt, D.; Schmidt, S.; Schmitt, S.; Schneider, M.; Schoeffel, L.; Schoning, A.; Schorner, T.; Schroder, V.; Schultz-Coulon, H.C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Chekelian, V.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Spitzer, H.; Stamen, R.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Tchetchelnitski, S.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Turney, J.E.; Tzamariudaki, E.; Uraev, A.; Urban, Marcel; Usik, A.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vassiliev, S.; Vazdik, Y.; Veelken, C.; Vest, A.; Vichnevski, A.; Wacker, K.; Wagner, J.; Wallny, R.; Waugh, B.; Weber, G.; Wegener, D.; Werner, C.; Werner, N.; Wessels, M.; White, G.; Wiesand, S.; Wilksen, T.; Winde, M.; Winter, G.G.; Wissing, C.; Wobisch, M.; Woehrling, E.E.; Wunsch, E.; Wyatt, A.C.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zomer, F.; zur Nedden, M.

2002-01-01

A search for excited electron e* production is described in which the electroweak decays e*->e gamma, e*->e Z and e*->nu W are considered. The data used correspond to an integrated luminosity of 120 pb^(-1) taken in e^(+-)p collisions from 1994 to 2000 with the H1 detector at HERA at centre-of-mass energies of 300 and 318 GeV. No evidence for a signal is found. Mass dependent exclusion limits are derived for the ratio of the couplings to the compositeness scale, f/Lambda. These limits extend the excluded region to higher masses than has been possible in previous direct searches for excited electrons.

A continuous flow isotope ratio mass spectrometry method for high precision determination of dissolved gas ratios and isotopic composition

DEFF Research Database (Denmark)

Charoenpong, C. N.; Bristow, L. A.; Altabet, M. A.

2014-01-01

ratio mass spectrometer (IRMS). A continuous flow of He carrier gas completely degasses the sample, and passes through the preparation and purification system before entering the IRMS for analysis. The use of this continuous He carrier permits short analysis times (less than 8 min per sample......) as compared with current high-precision methods. In addition to reference gases, calibration is achieved using air-equilibrated water standards of known temperature and salinity. Assessment of reference gas injections, air equilibrated standards, as well as samples collected in the field shows the accuracy...

Dynamics and control of high area-to-mass ratio spacecraft and its application to geomagnetic exploration

Science.gov (United States)

Luo, Tong; Xu, Ming; Colombo, Camilla

2018-04-01

This paper studies the dynamics and control of a spacecraft, whose area-to-mass ratio is increased by deploying a reflective orientable surface such as a solar sail or a solar panel. The dynamical system describing the motion of a non-zero attitude angle high area-to-mass ratio spacecraft under the effects of the Earth's oblateness and solar radiation pressure admits the existence of equilibrium points, whose number and the eccentricity values depend on the semi-major axis, the area-to-mass ratio and the attitude angle of the spacecraft together. When two out of three parameters are fixed, five different dynamical topologies successively occur through varying the third parameter. Two of these five topologies are critical cases characterized by the appearance of the bifurcation phenomena. A conventional Hamiltonian structure-preserving (HSP) controller and an improved HSP controller are both constructed to stabilize the hyperbolic equilibrium point. Through the use of a conventional HSP controller, a bounded trajectory around the hyperbolic equilibrium point is obtained, while an improved HSP controller allows the spacecraft to easily transfer to the hyperbolic equilibrium point and to follow varying equilibrium points. A bifurcation control using topologies and changes of behavior areas can also stabilize a spacecraft near a hyperbolic equilibrium point. Natural trajectories around stable equilibrium point and these stabilized trajectories around hyperbolic equilibrium point can all be applied to geomagnetic exploration.

Inductively coupled plasma-mass spectrometry for elemental analysis and isotope ratio determinations in individual organic compounds separated by gas chromatography

International Nuclear Information System (INIS)

Chong, N.S.; Houk, R.S.

1987-01-01

A gas chromatograph (GC) with a packed column was interfaced to an inductively coupled plasma-mass spectrometer (ICP-MS) to yield atomic mass spectra from volatile organic compounds. Atomization of injected compounds was nearly complete and independent of molecular structure, so that elemental ratios could be determined. Detection limits were in the range 0.001 to 400 ng s -1 , depending on the ionization energy of the element and its abundance in the background spectrum. The relative standard deviation of measured isotope ratios varied from 0.4% for Br (i.e., a ratio close to unity) to 18% for N (a very large ratio). Thus, GC-ICP-MS provides elemental and isotope ratio information that is complementary to the molecular information derived from GC-MS with conventional ionization methods

Influence of conservative corrections on parameter estimation for extreme-mass-ratio inspirals

International Nuclear Information System (INIS)

Huerta, E. A.; Gair, Jonathan R.

2009-01-01

We present an improved numerical kludge waveform model for circular, equatorial extreme-mass-ratio inspirals (EMRIs). The model is based on true Kerr geodesics, augmented by radiative self-force corrections derived from perturbative calculations, and in this paper for the first time we include conservative self-force corrections that we derive by comparison to post-Newtonian results. We present results of a Monte Carlo simulation of parameter estimation errors computed using the Fisher matrix and also assess the theoretical errors that would arise from omitting the conservative correction terms we include here. We present results for three different types of system, namely, the inspirals of black holes, neutron stars, or white dwarfs into a supermassive black hole (SMBH). The analysis shows that for a typical source (a 10M · compact object captured by a 10 6 M · SMBH at a signal to noise ratio of 30) we expect to determine the two masses to within a fractional error of ∼10 -4 , measure the spin parameter q to ∼10 -4.5 , and determine the location of the source on the sky and the spin orientation to within 10 -3 steradians. We show that, for this kludge model, omitting the conservative corrections leads to a small error over much of the parameter space, i.e., the ratio R of the theoretical model error to the Fisher matrix error is R<1 for all ten parameters in the model. For the few systems with larger errors typically R<3 and hence the conservative corrections can be marginally ignored. In addition, we use our model and first-order self-force results for Schwarzschild black holes to estimate the error that arises from omitting the second-order radiative piece of the self-force. This indicates that it may not be necessary to go beyond first order to recover accurate parameter estimates.

High-precision lead isotope ratio measurement by inductively coupled plasma multiple collector mass spectrometry

International Nuclear Information System (INIS)

Walder, A.J.; Furuta, Naoki.

1993-01-01

An inductively coupled plasma (ICP) ion source coupled to a magnetic sector mass analyser equipped with seven Faraday detectors has been used to measure the lead isotope ratios in solutions of Sanshiro Pond sediment collected at the University of Tokyo, airborne particulates collected at Shinjuku in Tokyo and Merck multielement standard product number 97279494. A thallium correction technique was utilized to allow a simultaneous correction for mass bias. This work followed an earlier interlaboratory comparison study of the above-mentioned solutions using ICP quadrupole mass spectrometry, and has demonstrated a considerable improvement in analytical precision. The following isotope ratio measurements were recorded. Pond sediment solution containing 82 ng ml -1 lead: 206 Pb/ 204 Pb=17.762±0.014; 206 Pb/ 207 Pb=1.1424±0.0009; 208 Pb/ 204 Pb=37.678±0.034. Airborne particulate solution containing 45 ng ml -1 lead: 206 Pb/ 204 Pb=17.969±0.006; 206 Pb/ 207 Pb=1.1528±0.0003; 208 Pb/ 204 Pb=37.915±0.021. Merck multielement standard solution containing 100 ng ml -1 lead: 206 Pb/ 204 Pb=19.255±0.015; 206 Pb/ 207 Pb=1.2238±0.0004; 208 Pb/ 204 Pb=38.476±0.021 (All errors are given as ±2 standard deviations). (author)

First Penning-trap mass measurement of the electron capture nuclide {sup 163}Ho and its daughter {sup 163}Dy for the ECHO project

Energy Technology Data Exchange (ETDEWEB)

Schneider, Fabian [Institut fuer Kernchemie und Institut fuer Physik, Johannes Gutenberg-Universitaet Mainz (Germany); Collaboration: TRIGA-SPEC Collaboration; ECHo-Collaboration

2015-07-01

The ECHo (Electron Capture of {sup 163}Ho) project aims to determine the mass of the electron neutrino by measuring the calorimetric spectrum of {sup 163}Ho. To be able to extract the neutrino mass from the spectrum near the endpoint a precise knowledge of the decay Q-value is necessary. The ideal way to measure this in a model independent way is by high-precision Penning-trap mass spectrometry. The ECHo collaboration has {sup 163}Ho samples available, which were produced by reactor neutron irradiation. Such samples are typically highly contaminated with radioactive and stable species. These were efficiently removed by chemical purification. Ionization by laser ablation allows high-precision Penning-trap mass measurements with sample sizes of 10{sup 16} atoms. From the measured cyclotron frequency ratio of {sup 163}Ho{sup 16}O{sup +} to {sup 163}Dy{sup 16}O{sup +} we determined the Q-value to be 2.5(7) keV. In addition absolute mass measurements using carbon cluster ions as reference were performed with an uncertainty two times lower than literature values. Future measurements at SHIPTRAP (GSI, Darmstadt) and PENTATRAP (MPIK, Heidelberg) are planned with the aim to drastically improve the uncertainty of the Q-value down to a few eV and thus providing the required input for the ECHo project.

THE IMPACT OF MASS SEGREGATION AND STAR FORMATION ON THE RATES OF GRAVITATIONAL-WAVE SOURCES FROM EXTREME MASS RATIO INSPIRALS

Energy Technology Data Exchange (ETDEWEB)

Aharon, Danor; Perets, Hagai B. [Physics Department, Technion—Israel Institute of Technology, Haifa 3200003 (Israel)

2016-10-10

Compact stellar objects inspiraling into massive black holes (MBHs) in galactic nuclei are some of the most promising gravitational-wave (GWs) sources for next-generation GW detectors. The rates of such extreme mass ratio inspirals (EMRIs) depend on the dynamics and distribution of compact objects (COs) around the MBH. Here, we study the impact of mass-segregation processes on EMRI rates. In particular, we provide the expected mass function (MF) of EMRIs, given an initial MF of stellar black holes (SBHs), and relate it to the mass-dependent detection rate of EMRIs. We then consider the role of star formation (SF) on the distribution of COs and its implication on EMRI rates. We find that the existence of a wide spectrum of SBH masses leads to the overall increase of EMRI rates and to high rates of the EMRIs from the most massive SBHs. However, it also leads to a relative quenching of EMRI rates from lower-mass SBHs, and together produces a steep dependence of the EMRI MF on the highest-mass SBHs. SF history plays a relatively small role in determining the EMRI rates of SBHs, since most of them migrate close to the MBH through mass segregation rather than forming in situ. However, the EMRI rate of neutron stars (NSs) can be significantly increased when they form in situ close to the MBH, as they can inspiral before relaxation processes significantly segregate them outward. A reverse but weaker effect of decreasing the EMRI rates from NSs and white dwarfs occurs when SF proceeds far from the MBH.

Application of gas chromatography-mass spectrometry/combustion/isotope ratio mass spectrometry (GC-MS/C/IRMS) to detect the abuse of 17β-estradiol in cattle.

Science.gov (United States)

Janssens, Geert; Mangelinckx, Sven; Courtheyn, Dirk; Prévost, Stéphanie; De Poorter, Geert; De Kimpe, Norbert; Le Bizec, Bruno

2013-07-31

Although the ability to differentiate between endogenous steroids and synthetic homologues on the basis of their (13)C/(12)C isotopic ratio has been known for over a decade, this technique has been scarcely implemented for food safety purposes. In this study, a method was developed using gas chromatography-mass spectrometry/combustion/isotope ratio mass spectrometry (GC-MS/C/IRMS) to demonstrate the abuse of 17β-estradiol in cattle, by comparison of the (13)C/(12)C ratios of the main metabolite 17α-estradiol and an endogenous reference compound (ERC), 5-androstene-3β,17α-diol, in bovine urine. The intermediate precisions were determined as 0.46 and 0.26‰ for 5-androstene-3β,17α-diol and 17α-estradiol, respectively. This is, to the authors' knowledge, the first reported use of GC-MS/C/IRMS for the analysis of steroid compounds for food safety issues.

Electron capture on 20Ne and the ultimate fate of stars in the mass range 8-10 M⊙

International Nuclear Information System (INIS)

Kirsebom, Oliver S.; Cederkall, Joakim; Jenkins, David G.; Joshi, Pankaj; Julin, Rauno; Kankainen, Anu; Trzaska, Wladyslaw H.; Kibedi, Tibor; Tengblad, Olof

2016-01-01

Knowledge of the electron-capture rate on 20 Ne is of critical importance to understand the final evolution of stars in the mass range 8-10M⊙. A recent study has highlighted the importance of the second-forbidden transition between the ground states of 20 Ne and 20 F, which is believed to dominate the capture rate in an important temperature-density range. The strength of this transition is, however, not well constrained, neither experimentally nor theoretically, making an experimental determination highly desirable. The transition strength can be determined from the branching ratio of the inverse transition in the decay of 20 F, for which the experimental upper limit is 10 -5 , while the most recent theoretical prediction is 1.3 x 10 -6 . To facilitate an experimental determination of the branching ratio we are refurbishing an intermediate-image magnetic spectrometer capable of focusing 7 MeV electrons, and designing a scintillator detector surrounded by an active cosmic-ray veto shield, which will serve as an energy- dispersive device at the focal plane. In this contribution, GEANT4 simulations of the expected performance of the setup will be presented and the astrophysical motivation for the experiment will be discussed. (author)

Polyquant CT: direct electron and mass density reconstruction from a single polyenergetic source

Science.gov (United States)

Mason, Jonathan H.; Perelli, Alessandro; Nailon, William H.; Davies, Mike E.

2017-11-01

Quantifying material mass and electron density from computed tomography (CT) reconstructions can be highly valuable in certain medical practices, such as radiation therapy planning. However, uniquely parameterising the x-ray attenuation in terms of mass or electron density is an ill-posed problem when a single polyenergetic source is used with a spectrally indiscriminate detector. Existing approaches to single source polyenergetic modelling often impose consistency with a physical model, such as water-bone or photoelectric-Compton decompositions, which will either require detailed prior segmentation or restrictive energy dependencies, and may require further calibration to the quantity of interest. In this work, we introduce a data centric approach to fitting the attenuation with piecewise-linear functions directly to mass or electron density, and present a segmentation-free statistical reconstruction algorithm for exploiting it, with the same order of complexity as other iterative methods. We show how this allows both higher accuracy in attenuation modelling, and demonstrate its superior quantitative imaging, with numerical chest and metal implant data, and validate it with real cone-beam CT measurements.

Correction of mass spectrometric isotope ratio measurements for isobaric isotopologues of O2, CO, CO2, N2O and SO2.

Science.gov (United States)

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. Copyright 2008 John Wiley & Sons, Ltd.

Determination of isotope ratios of metals (and metalloids) by means of inductively coupled plasma-mass spectrometry for provenancing purposes - A review

International Nuclear Information System (INIS)

Balcaen, L.; Moens, L.; Vanhaecke, F.

2010-01-01

Since considerable time, isotopic analysis of different elements present in a sample, material or object (such as the 'light' elements H, C, N, O and S and 'heavy' elements, such as Sr and Pb), has been used in provenancing studies, as several factors - defined by 'the environment' or origin of the sample - can lead to measurable differences in their isotopic composition. For the light elements, traditionally, (gas source) isotope ratio mass spectrometry (IR-MS) is used, while for a long period of time, thermal ionization mass spectrometry (TIMS) was considered as the only technique capable of detecting subtle variations in the isotopic composition of the 'heavier' elements. However, since the introduction of the first inductively coupled plasma mass spectrometers (ICP-MS), considerable attention has been devoted to the development of methodologies and strategies to perform isotopic analysis by means of ICP-MS. While the relatively modest isotope ratio precision offered by single-collector ICP-MS may already be fit-for-purpose under some circumstances, especially the introduction of multi-collector ICP-MS instruments, equipped with an array of Faraday detectors instead of a single electron multiplier, has lead to tremendous improvements in the field of isotopic analysis. As a result, MC-ICP-MS can be seen as a very strong competitor of TIMS nowadays, while it even provides information on the small isotopic variations shown by some elements, that are not or hardly accessible by means of TIMS (e.g., elements with a high ionization energy). Owing to these new instrumental developments, the application field of isotopic analysis by means of ICP-MS is continuously growing, also in the field of provenance determination. This paper is intended as a review of the developments in and the recent applications of isotopic analysis by means of ICP-MS in this specific research field.

Neutrino photoproduction on an electron in the QED two-dimensional approximation

International Nuclear Information System (INIS)

Loskutov, Yu.M.; Skobelev, V.V.

1980-01-01

Characteristic reactions of electron and muon neutrino photoproduction on an electron in a strong magnetic field are considered in the Weinberg model. The ratio of the corresponding cross sections depending on the charged boson mass permits to cherish hopes on the possibility of evaluating its mass on the basis of the experiment according to neutrino luminosity of neutron stars [ru

Study of the mass of the electron neutrino in Japan

Energy Technology Data Exchange (ETDEWEB)

Yasumi, Shinjiro; Maezawa, Hideki [eds.

1996-02-01

This report describes a study of the mass of the electron neutrino using electron capture in {sup 163}Ho in Japan for the period from 1981 to 1994. This monograph has two purposes, one is to supplement the papers on the mass of the electron neutrino already published by us and another is to make a record on some details of our experiments for future. Electron capture in a nucleus takes place in a rather small space inside an atom, where atomic physics, nuclear physics and particle physics work closely together. Therefore, this study needed an intimate collaboration of atomic physicists, nuclear physicists and particle physicists. In addition, it was necessary for this study to use various fine techniques, including metallurgy, production of {sup 163}Ho activity, micro-analysis by wet chemistry, isotope-dilution mass spectrometry, undulator radiation source technology, the soft X-ray monochromator technology, a counting technique for very intense soft X-rays and so on. As a result, our collaboration consisted of many researchers from various fields as follows; M. Ando, H. Arai, M. Fujioka, N. Hashimoto, H. Ikeda, Y. Inagaki, K. Ishii, K. Itoh, G. Izawa, O. Kawakami, S. Kishimoto, H. Kitamura, H. Maezawa, M. Maruyama, A. Masuda, K. Masumoto, A. Mikuni, T. Mizogawa, T. Mukoyama, F. Ochiai, T. Ohta, T. Omori, G. Rajasekaran, K. Sera, K. Shima, T. Shinozuka, P.M. Stefan, I. Sugai, H. Taketani, M. Yagi, and S. Yasumi. Without such an excellent collaboration, this study would not have been completed. We would like to express our sincere gratitude to Professor T. Sasaki for supporting this study and recommending the undulator beam line of 2.5 GeV Photon Factory Storage Ring as a light source to be used in the experiment. We also would like to thank Dr. A. Yagishita and Dr. Y. Kitajima who are responsible for the BL-2 beamline. Finally we are grateful to Ms. M. Noji for her patient typewriting of manuscripts written by hand. (author).

Study of the mass of the electron neutrino in Japan

International Nuclear Information System (INIS)

Yasumi, Shinjiro; Maezawa, Hideki

1996-02-01

This report describes a study of the mass of the electron neutrino using electron capture in 163 Ho in Japan for the period from 1981 to 1994. This monograph has two purposes, one is to supplement the papers on the mass of the electron neutrino already published by us and another is to make a record on some details of our experiments for future. Electron capture in a nucleus takes place in a rather small space inside an atom, where atomic physics, nuclear physics and particle physics work closely together. Therefore, this study needed an intimate collaboration of atomic physicists, nuclear physicists and particle physicists. In addition, it was necessary for this study to use various fine techniques, including metallurgy, production of 163 Ho activity, micro-analysis by wet chemistry, isotope-dilution mass spectrometry, undulator radiation source technology, the soft X-ray monochromator technology, a counting technique for very intense soft X-rays and so on. As a result, our collaboration consisted of many researchers from various fields as follows; M. Ando, H. Arai, M. Fujioka, N. Hashimoto, H. Ikeda, Y. Inagaki, K. Ishii, K. Itoh, G. Izawa, O. Kawakami, S. Kishimoto, H. Kitamura, H. Maezawa, M. Maruyama, A. Masuda, K. Masumoto, A. Mikuni, T. Mizogawa, T. Mukoyama, F. Ochiai, T. Ohta, T. Omori, G. Rajasekaran, K. Sera, K. Shima, T. Shinozuka, P.M. Stefan, I. Sugai, H. Taketani, M. Yagi, and S. Yasumi. Without such an excellent collaboration, this study would not have been completed. We would like to express our sincere gratitude to Professor T. Sasaki for supporting this study and recommending the undulator beam line of 2.5 GeV Photon Factory Storage Ring as a light source to be used in the experiment. We also would like to thank Dr. A. Yagishita and Dr. Y. Kitajima who are responsible for the BL-2 beamline. Finally we are grateful to Ms. M. Noji for her patient typewriting of manuscripts written by hand. (author)

STRAPS v1.0: evaluating a methodology for predicting electron impact ionisation mass spectra for the aerosol mass spectrometer

Directory of Open Access Journals (Sweden)

D. O. Topping

2017-06-01

Full Text Available Our ability to model the chemical and thermodynamic processes that lead to secondary organic aerosol (SOA formation is thought to be hampered by the complexity of the system. While there are fundamental models now available that can simulate the tens of thousands of reactions thought to take place, validation against experiments is highly challenging. Techniques capable of identifying individual molecules such as chromatography are generally only capable of quantifying a subset of the material present, making it unsuitable for a carbon budget analysis. Integrative analytical methods such as the Aerosol Mass Spectrometer (AMS are capable of quantifying all mass, but because of their inability to isolate individual molecules, comparisons have been limited to simple data products such as total organic mass and the O : C ratio. More detailed comparisons could be made if more of the mass spectral information could be used, but because a discrete inversion of AMS data is not possible, this activity requires a system of predicting mass spectra based on molecular composition. In this proof-of-concept study, the ability to train supervised methods to predict electron impact ionisation (EI mass spectra for the AMS is evaluated. Supervised Training Regression for the Arbitrary Prediction of Spectra (STRAPS is not built from first principles. A methodology is constructed whereby the presence of specific mass-to-charge ratio (m∕z channels is fitted as a function of molecular structure before the relative peak height for each channel is similarly fitted using a range of regression methods. The widely used AMS mass spectral database is used as a basis for this, using unit mass resolution spectra of laboratory standards. Key to the fitting process is choice of structural information, or molecular fingerprint. Our approach relies on using supervised methods to automatically optimise the relationship between spectral characteristics and these molecular

STRAPS v1.0: evaluating a methodology for predicting electron impact ionisation mass spectra for the aerosol mass spectrometer

Science.gov (United States)

Topping, David O.; Allan, James; Rami Alfarra, M.; Aumont, Bernard

2017-06-01

Our ability to model the chemical and thermodynamic processes that lead to secondary organic aerosol (SOA) formation is thought to be hampered by the complexity of the system. While there are fundamental models now available that can simulate the tens of thousands of reactions thought to take place, validation against experiments is highly challenging. Techniques capable of identifying individual molecules such as chromatography are generally only capable of quantifying a subset of the material present, making it unsuitable for a carbon budget analysis. Integrative analytical methods such as the Aerosol Mass Spectrometer (AMS) are capable of quantifying all mass, but because of their inability to isolate individual molecules, comparisons have been limited to simple data products such as total organic mass and the O : C ratio. More detailed comparisons could be made if more of the mass spectral information could be used, but because a discrete inversion of AMS data is not possible, this activity requires a system of predicting mass spectra based on molecular composition. In this proof-of-concept study, the ability to train supervised methods to predict electron impact ionisation (EI) mass spectra for the AMS is evaluated. Supervised Training Regression for the Arbitrary Prediction of Spectra (STRAPS) is not built from first principles. A methodology is constructed whereby the presence of specific mass-to-charge ratio (m/z) channels is fitted as a function of molecular structure before the relative peak height for each channel is similarly fitted using a range of regression methods. The widely used AMS mass spectral database is used as a basis for this, using unit mass resolution spectra of laboratory standards. Key to the fitting process is choice of structural information, or molecular fingerprint. Our approach relies on using supervised methods to automatically optimise the relationship between spectral characteristics and these molecular fingerprints. Therefore

A very high yield electron impact ion source for analytical mass spectrometry

International Nuclear Information System (INIS)

Koontz, S.L.; Bonner Denton, M.

1981-01-01

A novel ion source designed for use in mass spectrometric determination of organic compounds is described. The source is designed around a low pressure, large volume, hot cathode Penning discharge. The source operates in the 10 -4 - 10 -7 torr pressure domain and is capable of producing focusable current densities several orders of magnitude greater than those produced by conventional Nier -type sources. Mass spectra of n-butane and octafluoro-2-butene are presented. An improved signal-to-noise ratio is demonstrated with a General Electric Monopole 300 mass spectrometer. (orig.)

Proposal on electron anti-neutrino mass measurement at INS

International Nuclear Information System (INIS)

Ohshima, Takayoshi.

1981-03-01

Some comment on the proposed experiment, namely the measurement of electron anti-neutrino mass, is described. Various experiments with the measurement of β-ray from tritium have been reported. The precise measurement of the shape of the Kurie plot is required in this kind of experiment. The present experiment aimed at more accurate determination of neutrino mass than any other previous ones. An important point of the present experiment is to reduce the background due to the β-ray from evaporating tritium. The source candidates have low evaporation rate. A double focus √2π air core spectrometer is employed for the measurement of β-ray. The spectrometer was improved to meet the present purpose. The accumulated event rate was expected to be about 10 times higher than Russian experiment. The estimated energy resolution was about 30 eV. The neutrino mass with less than 10 eV accuracy will be obtained. (Kato, T.)

Resonant spin-flavor conversion of supernova neutrinos: Dependence on electron mole fraction

International Nuclear Information System (INIS)

Yoshida, Takashi; Takamura, Akira; Kimura, Keiichi; Yokomakura, Hidekazu; Kawagoe, Shio; Kajino, Toshitaka

2009-01-01

Detailed dependence of resonant spin-flavor (RSF) conversion of supernova neutrinos on electron mole fraction Y e is investigated. Supernova explosion forms a hot-bubble and neutrino-driven wind region of which electron mole fraction exceeds 0.5 in several seconds after the core collapse. When a higher resonance of the RSF conversion is located in the innermost region, flavor change of the neutrinos strongly depends on the sign of 1-2Y e . At an adiabatic high RSF resonance the flavor conversion of ν e ↔ν μ,τ occurs in Y e e >0.5 and inverted mass hierarchy. In other cases of Y e values and mass hierarchies, the conversion of ν e ↔ν μ,τ occurs. The final ν e spectrum is evaluated in the cases of Y e e >0.5 taking account of the RSF conversion. Based on the obtained result, time variation of the event number ratios of low ν e energy to high ν e energy is discussed. In normal mass hierarchy, an enhancement of the event ratio should be seen in the period when the electron fraction in the innermost region exceeds 0.5. In inverted mass hierarchy, on the other hand, a dip of the event ratio should be observed. Therefore, the time variation of the event number ratio is useful to investigate the effect of the RSF conversion.

Review: Current applications and challenges for liquid chromatography coupled to isotope ratio mass spectrometry (LC/IRMS).

Science.gov (United States)

Godin, Jean-Philippe; McCullagh, James S O

2011-10-30

High-precision isotope analysis is recognized as an essential research tool in many fields of study. Until recently, continuous flow isotope ratio mass spectrometry (CF-IRMS) was available via an elemental analyzer or a gas chromatography inlet system for compound-specific analysis of light stable isotopes. In 2004, however, an interface that coupled liquid chromatography with IRMS (LC/IRMS) became commercially available for the first time. This brought the capability for new areas of application, in particular enabling compound-specific δ(13)C analysis of non-volatile, aqueous soluble, compounds from complex mixtures. The interface design brought with it several analytical constraints, however, in particular a lack of compatibility with certain types of chromatography as well as limited flow rates and mobile phase compositions. Routine LC/IRMS methods have, however, been established for measuring the δ(13)C isotopic ratios of underivatized individual compounds for application in archeology, nutrition and physiology, geochemistry, hydrology, soil science and food authenticity. Seven years after its introduction, we review the technical advances and constraints, methodological developments and new applications of liquid chromatography coupled to isotope ratio mass spectrometry. Copyright © 2011 John Wiley & Sons, Ltd.

Value and Anisotropy of the Electron and Hole Mass in Pure Wurtzite InP Nanowires.

Science.gov (United States)

Tedeschi, D; De Luca, M; Granados Del Águila, A; Gao, Q; Ambrosio, G; Capizzi, M; Tan, H H; Christianen, P C M; Jagadish, C; Polimeni, A

2016-10-12

The effective mass of electrons and holes in semiconductors is pivotal in determining the dynamics of carriers and their confinement energy in nanostructured materials. Surprisingly, this quantity is still unknown in wurtzite (WZ) nanowires (NWs) made of III-V compounds (e.g., GaAs, InAs, GaP, InP), where the WZ phase has no bulk counterpart. Here, we investigate the magneto-optical properties of InP WZ NWs grown by selective-area epitaxy that provides perfectly ordered NWs featuring high-crystalline quality. The combined analysis of the energy of free exciton states and impurity levels under magnetic field (B up to 29 T) allows us to disentangle the dynamics of oppositely charged carriers from the Coulomb interaction and thus to determine the values of the electron and hole effective mass. By application of B⃗ along different crystallographic directions, we also assess the dependence of the transport properties with respect to the NW growth axis (namely, the WZ ĉ axis). The effective mass of electrons along ĉ is m e ∥ = (0.078 ± 0.002) m 0 (m 0 is the electron mass in vacuum) and perpendicular to ĉ is m e ⊥ = (0.093 ± 0.001) m 0 , resulting in a 20% mass anisotropy. Holes exhibit a much larger (∼320%) and opposite mass anisotropy with their effective mass along and perpendicular to ĉ equal to m h ∥ = (0.81 ± 0.18) m 0 and m h ⊥ = (0.250 ± 0.016) m 0 , respectively. While no full consensus is found with current theoretical results on WZ InP, our findings show trends remarkably similar to the experimental data available in WZ bulk materials, such as InN, GaN, and ZnO.

Isotopic distributions, element ratios, and element mass fractions from enrichment-meter-type gamma-ray measurements of MOX

International Nuclear Information System (INIS)

Close, D.A.; Parker, J.L.; Haycock, D.L.; Dragnev, T.

1991-01-01

The gamma-ray spectra from ''infinitely'' thick mixed oxide samples have been measured. The plutonium isotopics, the U/Pu ratio, the high-Z mass fractions (assuming only plutonium, uranium, and americium), and the low-Z mass fraction (assuming the matrix is only oxygen) can be determined by carefully analyzing the data. The results agree well with the chemical determination of these parameters. 8 refs., 3 figs., 3 tabs

Ratio of dietary ω-3 and ω-6 fatty acids-independent determinants of muscle mass-in hemodialysis patients with diabetes.

Science.gov (United States)

Wong, Te-Chih; Chen, Yu-Tong; Wu, Pei-Yu; Chen, Tzen-Wen; Chen, Hsi-Hsien; Chen, Tso-Hsiao; Hsu, Yung-Ho; Yang, Shwu-Huey

2016-09-01

ω-3 and ω-6 polyunsaturated fatty acids (PUFAs) are essential nutrients in the human diet and possibly affect muscle mass. We evaluated the association between the dietary ratios of ω-3 and ω-6 PUFAs and muscle mass, indicated as skeletal muscle mass (SMM) and appendicular skeletal muscle mass (ASM), in patients with diabetes undergoing hemodialysis (HD). In this cross-sectional study, data on 69 patients with diabetes who underwent standard HD therapy were analyzed. For estimating muscle mass, anthropometric and bioelectrical impedance analyses were conducted following dialysis. In addition, routine laboratory and 3-d dietary data were obtained. The adequate intake (AI) cut-off for ω-3 PUFAs was 1.6 g/d and 1.1 g/d for male and female patients, respectively. The average age of the participants was 63.0 ± 10.4 y. The mean ratios of ω-3/ω-6 PUFA intake, ω-6/ω-3 PUFA intake, SMM, and ASM of the patients were 0.13 ± 0.07, 9.4 ± 6.4, 24.6 ± 5.4 kg, and 18.3 ± 4.6 kg, respectively. Patients who had AI of ω-3 PUFAs had significantly higher SMM and ASM than did their counterparts. Linear and stepwise multivariable adjustment analyses revealed that insulin resistance and the ω-6/ω-3 PUFA ratio were the independent deleterious determinants of ASM normalized to height in HD patients. Patients with AI of ω-3 PUFAs had total-body SMM and ASM that were more appropriate. A higher dietary ratio of ω-6/ω-3 PUFAs was associated with reduced muscle mass in HD patients. Copyright © 2016 Elsevier Inc. All rights reserved.

Ratio of a strange quark mass ms to up or down quark mass mu,d predicted by a quark propagator in the framework of the chiral perturbation theory

International Nuclear Information System (INIS)

Peng Jinsong; Meng Chengju; Pan Jihuan; Yuan Tongquan; Zhou Lijuan; Ma Weixing

2013-01-01

Based on the fully dressed quark propagator and chiral perturbation theory, we study the ratio of the strange quark mass m s to up or down quark mass m u,d . The ratio is related to the determination of quark masses which are fundamental input parameters of QCD Lagrangian in the Standard Model of particle physics and can not be directly measured since the quark is confined within a hadron. An accurate determination of these QCD free parameters is extremely important for both phenomenological and theoretical applications. We begin with a brief introduction to the non-perturbation QCD theory, and then study the mass ratio in the framework of the chiral perturbation theory (χPT) with a parameterized fully dressed quark propagator which describes confining fully dressed quark propagation and is analytic everywhere in the finite complex p 2 -plane and has no Lehmann representation so there are no quark production thresholds in any theoretical calculations of observable data. Our prediction for the ratio m s /m u,d is consistent with other model predictions such as Lattice QCD, instanton model, QCD sum rules and the empirical values used widely in the literature. As a by-product of this study, our theoretical results, together with other predictions of physical quantities that used this quark propagator in our previous publications, clearly show that the parameterized form of the fully dressed quark propagator is an applicable and reliable approximation to the solution of the Dyson-Schwinger Equation of quark propagator in the QCD. (authors)

Determination of isotope ratio of elements by mass distribution in molecules of varied chemical compounds

International Nuclear Information System (INIS)

Gladkikh, I.S.; Babichev, A.P.

1999-01-01

The procedure and program for calculation of isotope ratio of elements involving in the compound being studied using data of mass spectrometry were elaborated. The methods developed for the O 2 , SiH 4 , Cd(CH 3 ) 2 molecules were demonstrated for the illustration. The results of calculation provide support for the efficiency of the program and satisfactory reliability of the results during calculation of the isotope and complex compound concentrations. The program may be used for the estimation of the degree of nonequilibrium isotope distributions, it may indicate on the errors of the mass spectroscopy results [ru

Design and realization of a space-borne reflectron time of flight mass spectrometer: electronics and measuring head

International Nuclear Information System (INIS)

Devoto, P.

2006-03-01

The purpose of this thesis is the design of the electronics of a time of flight mass spectrometer, the making and the vacuum tests of a prototype which can be put onboard a satellite. A particular effort was necessary to decrease to the maximum the mass and electric consumption of the spectrometer, which led to the development of new circuits. The work completed during this thesis initially concerns the electronics of the measuring equipment which was conceived in a concern for modularity. A complete 'reflectron' type mass spectrometer was then designed, simulated and developed. The built prototype, which uses the developed electronics, was exposed to ion flows of different masses and energies in the CESR vacuum chambers. Its measured performances validate the implemented principles and show that an identical mass spectrometer can be put onboard a satellite with profit, for planetary or solar missions. (author)

EXPLORING THE UNUSUALLY HIGH BLACK-HOLE-TO-BULGE MASS RATIOS IN NGC 4342 AND NGC 4291: THE ASYNCHRONOUS GROWTH OF BULGES AND BLACK HOLES

International Nuclear Information System (INIS)

Bogdán, Ákos; Forman, William R.; Kraft, Ralph P.; Li, Zhiyuan; Vikhlinin, Alexey; Nulsen, Paul E. J.; Jones, Christine; Zhuravleva, Irina; Churazov, Eugene; Mihos, J. Christopher; Harding, Paul; Guo, Qi; Schindler, Sabine

2012-01-01

We study two nearby early-type galaxies, NGC 4342 and NGC 4291, that host unusually massive black holes relative to their low stellar mass. The observed black-hole-to-bulge mass ratios of NGC 4342 and NGC 4291 are 6.9 +3.8 –2.3 % and 1.9% ± 0.6%, respectively, which significantly exceed the typical observed ratio of ∼0.2%. As a consequence of the exceedingly large black-hole-to-bulge mass ratios, NGC 4342 and NGC 4291 are ≈5.1σ and ≈3.4σ outliers from the M . -M bulge scaling relation, respectively. In this paper, we explore the origin of the unusually high black-hole-to-bulge mass ratio. Based on Chandra X-ray observations of the hot gas content of NGC 4342 and NGC 4291, we compute gravitating mass profiles, and conclude that both galaxies reside in massive dark matter halos, which extend well beyond the stellar light. The presence of dark matter halos around NGC 4342 and NGC 4291 and a deep optical image of the environment of NGC 4342 indicate that tidal stripping, in which ∼> 90% of the stellar mass was lost, cannot explain the observed high black-hole-to-bulge mass ratios. Therefore, we conclude that these galaxies formed with low stellar masses, implying that the bulge and black hole did not grow in tandem. We also find that the black hole mass correlates well with the properties of the dark matter halo, suggesting that dark matter halos may play a major role in regulating the growth of the supermassive black holes.

Quantitative analysis of the myelin g-ratio from electron microscopy images of the macaque corpus callosum

Directory of Open Access Journals (Sweden)

Nikola Stikov

2015-09-01

Full Text Available We provide a detailed morphometric analysis of eight transmission electron micrographs (TEMs obtained from the corpus callosum of one cynomolgus macaque. The raw TEM images are included in the article, along with the distributions of the axon caliber and the myelin g-ratio in each image. The distributions are analyzed to determine the relationship between axon caliber and g-ratio, and compared against the aggregate metrics (myelin volume fraction, fiber volume fraction, and the aggregate g-ratio, as defined in the accompanying research article entitled ‘In vivo histology of the myelin g-ratio with magnetic resonance imaging’ (Stikov et al., NeuroImage, 2015.

Major Mergers in CANDELS up to z=3: Calibrating the Close-Pair Method Using Semi-Analytic Models and Baryonic Mass Ratio Estimates

Science.gov (United States)

Mantha, Kameswara; McIntosh, Daniel H.; Conselice, Christopher; Cook, Joshua S.; Croton, Darren J.; Dekel, Avishai; Ferguson, Henry C.; Hathi, Nimish; Kodra, Dritan; Koo, David C.; Lotz, Jennifer M.; Newman, Jeffrey A.; Popping, Gergo; Rafelski, Marc; Rodriguez-Gomez, Vicente; Simmons, Brooke D.; Somerville, Rachel; Straughn, Amber N.; Snyder, Gregory; Wuyts, Stijn; Yu, Lu; Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey (CANDELS) Team

2018-01-01

Cosmological simulations predict that the rate of merging between similar-mass massive galaxies should increase towards early cosmic-time. We study the incidence of major (stellar mass ratio SMR 10.3 galaxies spanning 01.5 in strong disagreement with theoretical merger rate predictions. On the other hand, if we compare to a simulation-tuned, evolving timescale prescription from Snyder et al., 2017, we find that the merger rate evolution agrees with theory out to z=3. These results highlight the need for robust calibrations on the complex and presumably redshift-dependent pair-to-merger-rate conversion factors to improve constraints of the empirical merger history. To address this, we use a unique compilation of mock datasets produced by three independent state-of-the-art Semi-Analytic Models (SAMs). We present preliminary calibrations of the close-pair observability timescale and outlier fraction as a function of redshift, stellar-mass, mass-ratio, and local over-density. Furthermore, to verify the hypothesis by previous empirical studies that SMR-selection of major pairs may be biased, we present a new analysis of the baryonic (gas+stars) mass ratios of a subset of close pairs in our sample. For the first time, our preliminary analysis highlights that a noticeable fraction of SMR-selected minor pairs (SMR>4) have major baryonic-mass ratios (BMR<4), which indicate that merger rates based on SMR selection may be under-estimated.

The ratio DT/μ for electrons in water vapour at 294 K

International Nuclear Information System (INIS)

Elford, M.T.

1995-01-01

The ratio D T /μ for electrons in water vapour (294 K) has been measured by the Townsend-Huxley method as a function of E/N (where E is the electric field strength and N the gas number density) at vapour pressures ranging from 0.103 to 0.413 kPa. For E/N ≤ 30 Td, where attachment and ionisation may be neglected, the values are found to be independent of vapour pressure and of the current ratio relation used to derive D T /μ values from the measured current ratios. The uncertainty of these D T /μ values is estimated to be T /μ measured at E/N > 30 Td were found to be strongly pressure dependent, the strength and sign of the dependence depending on E/N and the current ratio relation used. Since extrapolation to infinite pressure at each E/N value did not give the same value of D T /μ, it has not been possible to derive reliable D T /μ values for this higher E/N range. Possible causes of the observed pressure dependences are discussed. The present data are in good agreement with the values predicted by Ness and Robson for values of E/N ≤ 24 Td. 17 refs., 1 tab., 5 figs

E2,M1 Multipole mixing ratios in odd-mass nuclei, 59< or =A< or =149

International Nuclear Information System (INIS)

Krane, K.S.

1977-01-01

A survey is presented of the E2,M1 mxing ratios of gamma-ray transitions in odd-mass nuclei with 59< or =A< or =149. Angular distribution and correlation data from the literature are analyzed in terms of a consistent choice of the phase relationship between the E2 and M1 matrix elements. A set of recommended values of the mixing ratios is included, based on averages of results from various studies. The survey includes data available in the literature up to September 1976

Improving the signal-to-noise ratio in mass and ion kinetic energy spectrometers

International Nuclear Information System (INIS)

Brenton, A.G.; Beynon, J.H.; Morgan, R.P.

1979-01-01

The signal-to-noise ratio in mass and ion kinetic energy spectrometers is limited by noise generated from the presence of scattered ions and neutrals. Methods of eliminating this are illustrated with reference to the ZAB-2F instrument manufactured by VG-Micromass Ltd. It is estimated that after the modifications the instrument is capable, on a routine basis, of measuring peaks corresponding to the arrival of ions at a rate of the order of 1 ion s -1 . (Auth.)

Maximum mass ratio of am CVn-type binary systems and maximum white dwarf mass in ultra-compact x-ray binaries (addendum - Serb. Astron. J. No. 183 (2011, 63

Directory of Open Access Journals (Sweden)

Arbutina B.

2012-01-01

Full Text Available We recalculated the maximum white dwarf mass in ultra-compact X-ray binaries obtained in an earlier paper (Arbutina 2011, by taking the effects of super-Eddington accretion rate on the stability of mass transfer into account. It is found that, although the value formally remains the same (under the assumed approximations, for white dwarf masses M2 >~0.1MCh mass ratios are extremely low, implying that the result for Mmax is likely to have little if any practical relevance.

Digitally synthesized high purity, high-voltage radio frequency drive electronics for mass spectrometry

Science.gov (United States)

Schaefer, R. T.; MacAskill, J. A.; Mojarradi, M.; Chutjian, A.; Darrach, M. R.; Madzunkov, S. M.; Shortt, B. J.

2008-09-01

Reported herein is development of a quadrupole mass spectrometer controller (MSC) with integrated radio frequency (rf) power supply and mass spectrometer drive electronics. Advances have been made in terms of the physical size and power consumption of the MSC, while simultaneously making improvements in frequency stability, total harmonic distortion, and spectral purity. The rf power supply portion of the MSC is based on a series-resonant LC tank, where the capacitive load is the mass spectrometer itself, and the inductor is a solenoid or toroid, with various core materials. The MSC drive electronics is based on a field programmable gate array (FPGA), with serial peripheral interface for analog-to-digital and digital-to-analog converter support, and RS232/RS422 communications interfaces. The MSC offers spectral quality comparable to, or exceeding, that of conventional rf power supplies used in commercially available mass spectrometers; and as well an inherent flexibility, via the FPGA implementation, for a variety of tasks that includes proportional-integral derivative closed-loop feedback and control of rf, rf amplitude, and mass spectrometer sensitivity. Also provided are dc offsets and resonant dipole excitation for mass selective accumulation in applications involving quadrupole ion traps; rf phase locking and phase shifting for external loading of a quadrupole ion trap; and multichannel scaling of acquired mass spectra. The functionality of the MSC is task specific, and is easily modified by simply loading FPGA registers or reprogramming FPGA firmware.

Digitally synthesized high purity, high-voltage radio frequency drive electronics for mass spectrometry.

Science.gov (United States)

Schaefer, R T; MacAskill, J A; Mojarradi, M; Chutjian, A; Darrach, M R; Madzunkov, S M; Shortt, B J

2008-09-01

Reported herein is development of a quadrupole mass spectrometer controller (MSC) with integrated radio frequency (rf) power supply and mass spectrometer drive electronics. Advances have been made in terms of the physical size and power consumption of the MSC, while simultaneously making improvements in frequency stability, total harmonic distortion, and spectral purity. The rf power supply portion of the MSC is based on a series-resonant LC tank, where the capacitive load is the mass spectrometer itself, and the inductor is a solenoid or toroid, with various core materials. The MSC drive electronics is based on a field programmable gate array (FPGA), with serial peripheral interface for analog-to-digital and digital-to-analog converter support, and RS232/RS422 communications interfaces. The MSC offers spectral quality comparable to, or exceeding, that of conventional rf power supplies used in commercially available mass spectrometers; and as well an inherent flexibility, via the FPGA implementation, for a variety of tasks that includes proportional-integral derivative closed-loop feedback and control of rf, rf amplitude, and mass spectrometer sensitivity. Also provided are dc offsets and resonant dipole excitation for mass selective accumulation in applications involving quadrupole ion traps; rf phase locking and phase shifting for external loading of a quadrupole ion trap; and multichannel scaling of acquired mass spectra. The functionality of the MSC is task specific, and is easily modified by simply loading FPGA registers or reprogramming FPGA firmware.

A review of electron-capture and electron-transfer dissociation tandem mass spectrometry in polymer chemistry

International Nuclear Information System (INIS)

Hart-Smith, Gene

2014-01-01

Graphical abstract: -- Highlights: •ECD and ETD can produce unique and diagnostically useful polymer ion fragmentation data. •The operating principles of ECD and ETD are discussed in relation to other dissociation techniques. •Key characteristics of ECD and ETD spectra, as observed from biological analytes, are discussed. •ECD and ETD analyses are compared to CID analyses for different classes of synthetic polymer. -- Abstract: Mass spectrometry (MS)-based studies of synthetic polymers often characterise detected polymer components using mass data alone. However when mass-based characterisations are ambiguous, tandem MS (MS/MS) offers a means by which additional analytical information may be collected. This review provides a synopsis of two particularly promising methods of dissociating polymer ions during MS/MS: electron-capture and electron-transfer dissociation (ECD and ETD, respectively). The article opens with a summary of the basic characteristics and operating principles of ECD and ETD, and relates these techniques to other methods of dissociating gas-phase ions, such as collision-induced dissociation (CID). Insights into ECD- and ETD-based MS/MS, gained from studies into proteins and peptides, are then discussed in relation to polymer chemistry. Finally, ECD- and ETD-based studies into various classes of polymer are summarised; for each polymer class, ECD- and ETD-derived data are compared to CID-derived data. These discussions identify ECD and ETD as powerful means by which unique and diagnostically useful polymer ion fragmentation data may be generated, and techniques worthy of increased utilisation by the polymer chemistry community

Highly Manufacturable Deep (Sub-Millimeter) Etching Enabled High Aspect Ratio Complex Geometry Lego-Like Silicon Electronics

KAUST Repository

Ghoneim, Mohamed T.; Hussain, Muhammad Mustafa

2017-01-01

A highly manufacturable deep reactive ion etching based process involving a hybrid soft/hard mask process technology shows high aspect ratio complex geometry Lego-like silicon electronics formation enabling free-form (physically flexible

Ratios of differential cross sections of heavy-flavour hadron production with ALICE

Energy Technology Data Exchange (ETDEWEB)

Hornung, Sebastian [Physikalisches Institut, Heidelberg (Germany); Collaboration: ALICE-Collaboration

2016-07-01

Measurements of heavy-flavour hadrons in pp collisions are important to test pertubative Quantum ChromoDynamics and as a reference for measurements in heavy-ion collisions. ALICE has measured several observables in this sector, e.g. p{sub T}-differential cross-sections of prompt D mesons and semi-electronic decays of beauty and charm hadrons at different energies. These measurements are compared to theoretical calculations, like General-Mass Variable Flavour Number Scheme (GM-VFNS) and Fixed-Order plus Next-to-Leading-Logarithms (FONLL), which are affected by large uncertainties caused by renormalisation scale, factorization scale and the heavy quark mass. Because of low statistics, the pp reference spectra for PbPb data are often obtained by extrapolation of data taken at different centre-of-mass energies. This procedure is guided by theory and also affected by large systematic uncertainties. The FONLL authors proposed to consider ratios of cross-sections at different centre-of-mass energies for a substantial reduction of the systematic uncertainties. Therefore, ratios of p{sub T}-differential cross-sections were studied to investigate the possibility to reduce theoretical uncertainties. Such ratios could benefit from the possibility to cancel some systematic errors on the measured data. Simulations with POWHEG are performed to provide an additional theory-based reference. By comparing calculated and measured ratios, sensitivity to the gluon distribution function may be obtained.

Online stable carbon isotope ratio measurement in formic acid, acetic acid, methanol and ethanol in water by high performance liquid chromatography-isotope ratio mass spectrometry

International Nuclear Information System (INIS)

Tagami, Keiko; Uchida, Shigeo

2008-01-01

A suitable analysis condition was determined for high performance liquid chromatography-isotope ratio mass spectrometry (HPLC-IRMS) while making sequential measurements of stable carbon isotope ratios of δ 13 C in formic acid, acetic acid, methanol and ethanol dissolved in water. For this online column separation method, organic reagents are not applicable due to carbon contamination; thus, water and KH 2 PO 4 at low concentrations were tested as mobile phase in combination with a HyPURITY AQUASTAR TM column. Formic acid, acetic acid, methanol and ethanol were separated when 2 mM KH 2 PO 4 aqueous solution was used. Under the determined analysis condition for HPLC-IRMS, carbon concentrations could be measured quantitatively as well as carbon isotope ratio when carbon concentration was higher than 0.4 mM L for each chemical

Complementation of mitochondrial electron transport chain by manipulation of the NAD+/NADH ratio.

Science.gov (United States)

Titov, Denis V; Cracan, Valentin; Goodman, Russell P; Peng, Jun; Grabarek, Zenon; Mootha, Vamsi K

2016-04-08

A decline in electron transport chain (ETC) activity is associated with many human diseases. Although diminished mitochondrial adenosine triphosphate production is recognized as a source of pathology, the contribution of the associated reduction in the ratio of the amount of oxidized nicotinamide adenine dinucleotide (NAD(+)) to that of its reduced form (NADH) is less clear. We used a water-forming NADH oxidase from Lactobacillus brevis (LbNOX) as a genetic tool for inducing a compartment-specific increase of the NAD(+)/NADH ratio in human cells. We used LbNOX to demonstrate the dependence of key metabolic fluxes, gluconeogenesis, and signaling on the cytosolic or mitochondrial NAD(+)/NADH ratios. Expression of LbNOX in the cytosol or mitochondria ameliorated proliferative and metabolic defects caused by an impaired ETC. The results underscore the role of reductive stress in mitochondrial pathogenesis and demonstrate the utility of targeted LbNOX for direct, compartment-specific manipulation of redox state. Copyright © 2016, American Association for the Advancement of Science.

Silicon isotope ratio measurements by inductively coupled plasma tandem mass spectrometry for alteration studies of nuclear waste glasses

Energy Technology Data Exchange (ETDEWEB)

Gourgiotis, Alkiviadis, E-mail: alkiviadis.gourgiotis@irsn.fr [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-DGE/SRTG/LT2S, Fontenay-aux-Roses (France); Ducasse, Thomas [CEA, DEN, DTCD, SECM, F-30207 Bagnols-sur-Cèze (France); Barker, Evelyne [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-DGE/SRTG/LT2S, Fontenay-aux-Roses (France); Jollivet, Patrick; Gin, Stéphane [CEA, DEN, DTCD, SECM, F-30207 Bagnols-sur-Cèze (France); Bassot, Sylvain; Cazala, Charlotte [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-DGE/SRTG/LT2S, Fontenay-aux-Roses (France)

2017-02-15

High-level, long-lived nuclear waste arising from spent fuel reprocessing is vitrified in silicate glasses for final disposal in deep geologic formations. In order to better understand the mechanisms driving glass dissolution, glass alteration studies, based on silicon isotope ratio monitoring of {sup 29}Si-doped aqueous solutions, were carried out in laboratories. This work explores the capabilities of the new type of quadrupole-based ICP-MS, the Agilent 8800 tandem quadrupole ICP-MS/MS, for accurate silicon isotope ratio determination for alteration studies of nuclear waste glasses. In order to avoid silicon polyatomic interferences, a new analytical method was developed using O{sub 2} as the reaction gas in the Octopole Reaction System (ORS), and silicon isotopes were measured in mass-shift mode. A careful analysis of the potential polyatomic interferences on SiO{sup +} and SiO{sub 2}{sup +} ion species was performed, and we found that SiO{sup +} ion species suffer from important polyatomic interferences coming from the matrix of sample and standard solutions (0.5M HNO{sub 3}). For SiO{sub 2}{sup +}, no interferences were detected, and thus, these ion species were chosen for silicon isotope ratio determination. A number of key settings for accurate isotope ratio analysis like, detector dead time, integration time, number of sweeps, wait time offset, memory blank and instrumental mass fractionation, were considered and optimized. Particular attention was paid to the optimization of abundance sensitivity of the quadrupole mass filter before the ORS. We showed that poor abundance sensitivity leads to a significant shift of the data away from the Exponential Mass Fractionation Law (EMFL) due to the spectral overlaps of silicon isotopes combined with different oxygen isotopes (i.e. {sup 28}Si{sup 16}O{sup 18}O{sup +}, {sup 30}Si{sup 16}O{sup 16}O{sup +}). The developed method was validated by measuring a series of reference solutions with different {sup 29}Si

Seasonal and spatial variability of the OM/OC mass ratios and high regional correlation between oxalic acid and zinc in Chinese urban organic aerosols

Directory of Open Access Journals (Sweden)

L. Xing

2013-04-01

Full Text Available We calculated the organic matter to organic carbon mass ratios (OM/OC mass ratios in PM2.5 collected from 14 Chinese cities during summer and winter of 2003 and analyzed the causes for their seasonal and spatial variability. The OM/OC mass ratios were calculated two ways. Using a mass balance method, the calculated OM/OC mass ratios averaged 1.92 ± 0.39 year-round, with no significant seasonal or spatial variation. The second calculation was based on chemical species analyses of the organic compounds extracted from the PM2.5 samples using dichloromethane/methanol and water. The calculated OM/OC mass ratio in summer was relatively high (1.75 ± 0.13 and spatially-invariant due to vigorous photochemistry and secondary organic aerosol (OA production throughout the country. The calculated OM/OC mass ratio in winter (1.59 ± 0.18 was significantly lower than that in summer, with lower values in northern cities (1.51 ± 0.07 than in southern cities (1.65 ± 0.15. This likely reflects the wider usage of coal for heating purposes in northern China in winter, in contrast to the larger contributions from biofuel and biomass burning in southern China in winter. On average, organic matter constituted 36% and 34% of Chinese urban PM2.5 mass in summer and winter, respectively. We report, for the first time, a high regional correlation between Zn and oxalic acid in Chinese urban aerosols in summer. This is consistent with the formation of stable Zn oxalate complex in the aerosol phase previously proposed by Furukawa and Takahashi (2011. We found that many other dicarboxylic acids were also highly correlated with Zn in the summer Chinese urban aerosol samples, suggesting that they may also form stable organic complexes with Zn. Such formation may have profound implications for the atmospheric abundance and hygroscopic properties of aerosol dicarboxylic acids.

Seasonal and spatial variability of the OM/OC mass ratios and high regional correlation between oxalic acid and zinc in Chinese urban organic aerosols

Science.gov (United States)

Xing, L.; Fu, T.-M.; Cao, J. J.; Lee, S. C.; Wang, G. H.; Ho, K. F.; Cheng, M.-C.; You, C.-F.; Wang, T. J.

2013-04-01

We calculated the organic matter to organic carbon mass ratios (OM/OC mass ratios) in PM2.5 collected from 14 Chinese cities during summer and winter of 2003 and analyzed the causes for their seasonal and spatial variability. The OM/OC mass ratios were calculated two ways. Using a mass balance method, the calculated OM/OC mass ratios averaged 1.92 ± 0.39 year-round, with no significant seasonal or spatial variation. The second calculation was based on chemical species analyses of the organic compounds extracted from the PM2.5 samples using dichloromethane/methanol and water. The calculated OM/OC mass ratio in summer was relatively high (1.75 ± 0.13) and spatially-invariant due to vigorous photochemistry and secondary organic aerosol (OA) production throughout the country. The calculated OM/OC mass ratio in winter (1.59 ± 0.18) was significantly lower than that in summer, with lower values in northern cities (1.51 ± 0.07) than in southern cities (1.65 ± 0.15). This likely reflects the wider usage of coal for heating purposes in northern China in winter, in contrast to the larger contributions from biofuel and biomass burning in southern China in winter. On average, organic matter constituted 36% and 34% of Chinese urban PM2.5 mass in summer and winter, respectively. We report, for the first time, a high regional correlation between Zn and oxalic acid in Chinese urban aerosols in summer. This is consistent with the formation of stable Zn oxalate complex in the aerosol phase previously proposed by Furukawa and Takahashi (2011). We found that many other dicarboxylic acids were also highly correlated with Zn in the summer Chinese urban aerosol samples, suggesting that they may also form stable organic complexes with Zn. Such formation may have profound implications for the atmospheric abundance and hygroscopic properties of aerosol dicarboxylic acids.

Silicon isotope ratio measurements by inductively coupled plasma tandem mass spectrometry for alteration studies of nuclear waste glasses.

Science.gov (United States)

Gourgiotis, Alkiviadis; Ducasse, Thomas; Barker, Evelyne; Jollivet, Patrick; Gin, Stéphane; Bassot, Sylvain; Cazala, Charlotte

2017-02-15

High-level, long-lived nuclear waste arising from spent fuel reprocessing is vitrified in silicate glasses for final disposal in deep geologic formations. In order to better understand the mechanisms driving glass dissolution, glass alteration studies, based on silicon isotope ratio monitoring of 29 Si-doped aqueous solutions, were carried out in laboratories. This work explores the capabilities of the new type of quadrupole-based ICP-MS, the Agilent 8800 tandem quadrupole ICP-MS/MS, for accurate silicon isotope ratio determination for alteration studies of nuclear waste glasses. In order to avoid silicon polyatomic interferences, a new analytical method was developed using O 2 as the reaction gas in the Octopole Reaction System (ORS), and silicon isotopes were measured in mass-shift mode. A careful analysis of the potential polyatomic interferences on SiO + and SiO 2 + ion species was performed, and we found that SiO + ion species suffer from important polyatomic interferences coming from the matrix of sample and standard solutions (0.5M HNO 3 ). For SiO 2 + , no interferences were detected, and thus, these ion species were chosen for silicon isotope ratio determination. A number of key settings for accurate isotope ratio analysis like, detector dead time, integration time, number of sweeps, wait time offset, memory blank and instrumental mass fractionation, were considered and optimized. Particular attention was paid to the optimization of abundance sensitivity of the quadrupole mass filter before the ORS. We showed that poor abundance sensitivity leads to a significant shift of the data away from the Exponential Mass Fractionation Law (EMFL) due to the spectral overlaps of silicon isotopes combined with different oxygen isotopes (i.e. 28 Si 16 O 18 O + , 30 Si 16 O 16 O + ). The developed method was validated by measuring a series of reference solutions with different 29 Si enrichment. Isotope ratio trueness, uncertainty and repeatability were found to be

High-precision branching-ratio measurement for the superallowed β+ emitter 74Rb

Science.gov (United States)

Dunlop, R.; Ball, G. C.; Leslie, J. R.; Svensson, C. E.; Towner, I. S.; Andreoiu, C.; Chagnon-Lessard, S.; Chester, A.; Cross, D. S.; Finlay, P.; Garnsworthy, A. B.; Garrett, P. E.; Glister, J.; Hackman, G.; Hadinia, B.; Leach, K. G.; Rand, E. T.; Starosta, K.; Tardiff, E. R.; Triambak, S.; Williams, S. J.; Wong, J.; Yates, S. W.; Zganjar, E. F.

2013-10-01

A high-precision branching-ratio measurement for the superallowed β+ decay of 74Rb was performed at the TRIUMF Isotope Separator and Accelerator (ISAC) radioactive ion-beam facility. The scintillating electron-positron tagging array (SCEPTAR), composed of 10 thin plastic scintillators, was used to detect the emitted β particles; the 8π spectrometer, an array of 20 Compton-suppressed HPGe detectors, was used for detecting γ rays that were emitted following Gamow-Teller and nonanalog Fermi β+ decays of 74Rb; and the Pentagonal Array of Conversion Electron Spectrometers (PACES), an array of 5 Si(Li) detectors, was employed for measuring β-delayed conversion electrons. Twenty-three excited states were identified in 74Kr following 8.241(4)×108 detected 74Rb β decays. A total of 58 γ-ray and electron transitions were placed in the decay scheme, allowing the superallowed branching ratio to be determined as B0=99.545(31)%. Combined with previous half-life and Q-value measurements, the superallowed branching ratio measured in this work leads to a superallowed ft value of 3082.8(65) s. Comparisons between this superallowed ft value and the world-average-corrected Ft¯ value, as well as the nonanalog Fermi branching ratios determined in this work, provide guidance for theoretical models of the isospin-symmetry-breaking corrections in this mass region.

COSMOLOGICAL CONSTRAINTS FROM GALAXY CLUSTERING AND THE MASS-TO-NUMBER RATIO OF GALAXY CLUSTERS

International Nuclear Information System (INIS)

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

2012-01-01

We place constraints on the average density (Ω m ) and clustering amplitude (σ 8 ) of matter using a combination of two measurements from the Sloan Digital Sky Survey: the galaxy two-point correlation function, w p (r p ), and the mass-to-galaxy-number ratio within galaxy clusters, M/N, analogous to cluster M/L ratios. Our w p (r p ) 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 w p (r p ) 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 σ 8 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 w p (r p ) and M/N alone, we find Ω 0.5 m σ 8 = 0.465 ± 0.026, with individual constraints of Ω m = 0.29 ± 0.03 and σ 8 = 0.85 ± 0.06. Combined with current cosmic microwave background data, these constraints are Ω m = 0.290 ± 0.016 and σ 8 = 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.

COSMOLOGICAL CONSTRAINTS FROM GALAXY CLUSTERING AND THE MASS-TO-NUMBER RATIO OF GALAXY CLUSTERS

Energy Technology Data Exchange (ETDEWEB)

Tinker, Jeremy L.; Blanton, Michael R. [Center for Cosmology and Particle Physics, Department of Physics, New York University, New York, NY 10013 (United States); Sheldon, Erin S. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Wechsler, Risa H. [Kavli Institute for Particle Astrophysics and Cosmology, Physics Department, and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Becker, Matthew R.; Rozo, Eduardo [Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637 (United States); Zu, Ying; Weinberg, David H. [Department of Astronomy, Ohio State University, Columbus, OH 43210 (United States); Zehavi, Idit [Department of Astronomy and CERCA, Case Western Reserve University, Cleveland, OH 44106 (United States); Busha, Michael T. [Institute for Theoretical Physics, Department of Physics, University of Zurich, CH-8057 Zurich (Switzerland); Koester, Benjamin P. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 6037 (United States)

2012-01-20

We place constraints on the average density ({Omega}{sub m}) and clustering amplitude ({sigma}{sub 8}) of matter using a combination of two measurements from the Sloan Digital Sky Survey: the galaxy two-point correlation function, w{sub p} (r{sub p} ), and the mass-to-galaxy-number ratio within galaxy clusters, M/N, analogous to cluster M/L ratios. Our w{sub p} (r{sub p} ) 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 w{sub p} (r{sub p} ) 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 {Omega}{sub m} or {sigma}{sub 8} 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 w{sub p} (r{sub p} ) and M/N alone, we find {Omega}{sup 0.5}{sub m}{sigma}{sub 8} = 0.465 {+-} 0.026, with individual constraints of {Omega}{sub m} = 0.29 {+-} 0.03 and {sigma}{sub 8} = 0.85 {+-} 0.06. Combined with current cosmic microwave background data, these constraints are {Omega}{sub m} = 0.290 {+-} 0.016 and {sigma}{sub 8} = 0.826 {+-} 0.020. All errors are 1{sigma}. 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

Isotope ratio analysis by a combination of element analyzer and mass spectrometer

International Nuclear Information System (INIS)

Pichlmayer, F.

1987-06-01

The use of stable isotope ratios of carbon, nitrogen and sulfur as analytical tool in many fields of research is of growing interest. A method has therefore been developed, consisting in essential of coupling an Elemental Analyzer with an Isotope Mass Spectrometer, which enables the gas preparation of carbon dioxide, nitrogen and sulfur dioxide from any solid or liquid sample in a fast and easy way. Results of carbon isotope measurements in food analysis are presented, whereat it is possible to check origin and treatment of sugar, oils, fats, mineral waters, spirituous liquors etc. and to detect adulterations as well. Also applications in the field of environmental research are given. (Author)

SU-C-201-07: Towards Clinical Cherenkov Emission Dosimetry: Stopping Power-To-Cherenkov Power Ratios and Beam Quality Specification of Clinical Electron Beams

International Nuclear Information System (INIS)

Zlateva, Y; Seuntjens, J; El Naqa, I

2016-01-01

Purpose: We propose a Cherenkov emission (CE)-based reference dosimetry method, which in contrast to ionization chamber-based dosimetry, employs spectrum-averaged electron restricted mass collision stopping power-to-Cherenkov power ratios (SCRs), and we examine Monte Carlo-calculated SCRs and beam quality specification of clinical electron beams. Methods: The EGSnrc user code SPRRZnrc was modified to compute SCRs instead of stopping-power ratios (single medium: water; cut-off: CE threshold (observing Spencer-Attix conditions); CE power: Frank-Tamm). SCRs are calculated with BEAMnrc for realistic electron beams with nominal energies of 6–22 MeV from three Varian accelerators (TrueBeam Clinac 21EX, Clinac 2100C/D) and for mono-energetic beams of energies equal to the mean electron energy at the water surface. Sources of deviation between clinical and mono-energetic SCRs are analyzed quantitatively. A universal fit for the beam-quality index R_5_0 in terms of the depth of 50% CE C_5_0 is carried out. Results: SCRs at reference depth are overestimated by mono-energetic values by up to 0.2% for a 6-MeV beam and underestimated by up to 2.3% for a 22-MeV beam. The variation is mainly due to the clinical beam spectrum and photon contamination. Beam angular spread has a small effect across all depths and energies. The influence of the electron spectrum becomes increasingly significant at large depths, while at shallow depths and high beam energies photon contamination is predominant (up to 2.0%). The universal data fit reveals a strong linear correlation between R_5_0 and C_5_0 (ρ > 0.99999). Conclusion: CE is inherent to radiotherapy beams and can be detected outside the beam with available optical technologies, which makes it an ideal candidate for out-of-beam high-resolution 3D dosimetry. Successful clinical implementation of CE dosimetry hinges on the development of robust protocols for converting measured CE to radiation dose. Our findings constitute a key step

Two Balls' Collision of Mass Ratio 3:1

Science.gov (United States)

Ogawara, Yasuo; Hull, Michael M.

2018-04-01

Students will sometimes ask why momentum and kinetic energy concepts are both necessary. When physics teachers demonstrate situations that require both an understanding of kinetic energy and momentum, a favorite is Newton's cradle, or a comparable demonstration of two balls of equal mass hitting each other. However, in addition to the case of two balls of equal mass, if a ball hits another ball of three times the mass with equal speed, the results are also interesting, and, like the equal-mass demonstration, both kinetic energy and momentum are critical for understanding the motion.

Fat mass to fat-free mass ratio reference values from NHANES III using bioelectrical impedance analysis.

Science.gov (United States)

Xiao, J; Purcell, S A; Prado, C M; Gonzalez, M C

2017-10-06

Low fat-free mass (FFM) or high fat mass (FM) are abnormal body composition phenotypes associated with morbidity. These conditions in combination lead to worse health outcomes, and can be identified by a high FM/FFM ratio. Here, we developed sex, age, and body mass index (BMI) stratified, population-based FM/FFM reference values using bioelectrical impedance analysis (BIA) measurements. White, non-Hispanic individuals aged 18-90 years old with data for weight, stature and BIA resistance measures from the third National Health and Nutrition Examination Survey (NHANES) III were included. Previously validated and sex-specific BIA prediction equations were used to calculate FM and FFM. FM/FFM values were generated at 5th, 50th and 95th percentiles for each sex, age (18-39.9, 40-59.9, 60-69.9 and 70-90 years), and BMI category (underweight, normal weight, overweight, class I/II and class III obesity). A total of 6372 individuals who had estimated FM and FFM values were identified (3366 females, 3006 males). Median values of FM/FFM were 0.24 and 0.40 for young (≤39.9 years) males and females with normal BMI, and 0.34 for males and 0.59 for females who were overweight. For elderly individuals aged >70 years, median FM/FFM for males and females were respectively 0.28 and 0.45 for those with normal BMI, and 0.37 and 0.61 for those in the overweight category. These FM/FFM reference values provide information on body composition characteristics that account for age, sex and BMI, which can be useful to identify individuals at risk for body composition abnormalities. Copyright © 2017 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Ratios of regioisomers of minor acylglycerols less polar than triricinolein in castor oil estimated by mass spectrometry

Science.gov (United States)

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 ...

Using GC-combustion isotope ratio mass spectrometry for confirming steroid administration from urinary metabolites in humans and animals

International Nuclear Information System (INIS)

Phillips, A.; Churchman, D.; Davis, S.

2000-01-01

Gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) was used to study the incorporation of exogenous testosterone enanthate into excreted urinary 5α- and 5β-androstane-3α, 17β-diols

Charge and frequency resolved isochronous mass spectrometry and the mass of 51Co

International Nuclear Information System (INIS)

Shuai, P.; Xu, H.S.; Tu, X.L.; Zhang, Y.H.; Sun, B.H.; Wang, M.

2014-01-01

Revolution frequency measurements of individual ions in storage rings require sophisticated timing detectors. One of common approaches for such detectors is the detection of secondary electrons released from a thin foil due to penetration of the stored ions. A new method based on the analysis of intensities of secondary electrons was developed which enables determination of the charge of each ion simultaneously with the measurement of its revolution frequency. Although the mass-over-charge ratios of 51 Co 27+ and 34 Ar 18+ ions are almost identical, and therefore, the ions cannot be resolved in a storage ring, by applying the new method the mass excess of the short-lived 51 Co is determined for the first time to be ME( 51 Co)=−27342(48) keV. Shell-model calculations in the fp-shell nuclei compared to the new data indicate the need to include isospin-nonconserving forces

A Comparison of Vibroacoustic Response of Isotropic Plate with Attached Discrete Patches and Point Masses Having Different Thickness Variation with Different Taper Ratios

Directory of Open Access Journals (Sweden)

Bipin Kumar

2016-01-01

Full Text Available A comparison of sound radiation behavior of plate in air medium with attached discrete patches/point masses having different thickness variations with different taper ratio of 0.3, 0.6, and 0.9 is analysed. Finite element method is used to find the vibration characteristics while Rayleigh integral is used to predict the sound radiation characteristics. Minimum peak sound power level obtained is at a taper ratio of 0.6 with parabolic increasing-decreasing thickness variation for plate with four discrete patches. At higher taper ratio, linearly increasing-decreasing thickness variation is another alternative for minimum peak sound power level suppression with discrete patches. It is found that, in low frequency range, average radiation efficiency remains almost the same, but near first peak, four patches or four point masses cause increase in average radiation efficiency; that is, redistribution of point masses/patches does have effect on average radiation efficiency at a given taper ratio.

Charge–mass ratio bound and optimization in the Parikh–Wilczek tunneling model of Hawking radiation

International Nuclear Information System (INIS)

Kim, Kyung Kiu; Wen, Wen-Yu

2014-01-01

In this Letter, we study the mutual information hidden in the Parikh–Wilczek tunneling model of Hawking radiation for Reissner–Nordström black holes. We argue that the condition of nonnegativity of mutual information suggests bound(s) for charge–mass ratio of emitted particles. We further view the radiation as an optimization process and discuss its effect on time evolution of a charged black hole.

Determination of low-energy ion-induced electron yields from thin carbon foils

International Nuclear Information System (INIS)

Allegrini, Frederic; Wimmer-Schweingruber, Robert F.; Wurz, Peter; Bochsler, Peter

2003-01-01

Ion beams crossing thin carbon foils can cause electron emission from the entrance and exit surface. Thin carbon foils are used in various types of time-of-flight (TOF) mass spectrometers to produce start pulses for TOF measurements. The yield of emitted electrons depends, among other parameters, on the energy of the incoming ion and its mass, and it has been experimentally determined for a few projectile elements. The electron emission yield is of great importance for deriving abundance ratios of elements and isotopes in space plasmas using TOF mass spectrometers. We have developed a detector for measuring ion-induced electron yields, and we have extended the electron yield measurements for oxygen to energies relevant for solar wind research. We also present first measurements of the carbon foil electron emission yield for argon and iron in the solar wind energy range

Electronic sputtering of large organic molecules and its application in bio molecular mass spectrometry

International Nuclear Information System (INIS)

Sundqvist, B.U.R.

1992-01-01

This is a review of research which has its origin in the discovery of Plasma Desorption Mass Spectrometry (PDMS). Two main fields of research have developed, namely fundamental studies of the ejection process at fast ion impact and studies of applications of the new mass spectrometric technique. In this review the emphasis will be on the process of electronic sputtering of organic solids but also applications of this process in bio molecular mass spectrometry will be discussed. (author)

The interaction effect of body mass index and age on fat-free mass, waist-to-hip ratio, and soft lean mass

Directory of Open Access Journals (Sweden)

Alireza Shahab Jahanlou

2017-01-01

Full Text Available Background: Research has shown that body mass index (BMI does not take into consideration the gender and ethnicity. The primary purpose of this study was to examine the interaction effect of the BMI and age on fat-free mass (FFM, waist-to-hip ratio (WHR, and soft lean mass (SLM. The secondary purpose was to evaluate the practical significance of the findings by examining effect sizes. Materials and Methods: The study was comparative in nature and employed a factorial design. Due to nonexperimental nature of the investigation, no causal inferences were drawn. The nonprobability sample consisted of 19,356 adults. Analysis of the data included factorial analysis of variance, analysis of simple effects, calculation of mean difference effect sizes, and data transformation. The Statistical Package for the Social Sciences version 22 was employed for the purpose of data manipulation and analysis. Results: The BMI by age interaction effects on FFM, F (10, 19,338 = 28.26, P < 0.01, on WHR, F (10, 19,338 = 18.46, P < 0.01, and on SLM, F (10, 19,338 = 14.65, P < 0.01, was statistically significant and ordinal in nature. Analysis of the effect sizes, ranging from 0.30 to 1.20, showed that the BMI and age influenced the WHR but their interaction effects on FFM and SLM, ranging from 0.04 to 0.36 and 0.03 to 0.33, respectively, were mainly negligible. Conclusion: Based on the examination of the statistical and practical significance of the results, it is concluded that the BMI and age together can influence the WHR but their interaction effect on the FFM and SLM is questionable.

Isotope ratio mass spectrometry as a tool for source inference in forensic science: A critical review.

Science.gov (United States)

Gentile, Natacha; Siegwolf, Rolf T W; Esseiva, Pierre; Doyle, Sean; Zollinger, Kurt; Delémont, Olivier

2015-06-01

Isotope ratio mass spectrometry (IRMS) has been used in numerous fields of forensic science in a source inference perspective. This review compiles the studies published on the application of isotope ratio mass spectrometry (IRMS) to the traditional fields of forensic science so far. It completes the review of Benson et al. [1] and synthesises the extent of knowledge already gathered in the following fields: illicit drugs, flammable liquids, human provenancing, microtraces, explosives and other specific materials (packaging tapes, safety matches, plastics, etc.). For each field, a discussion assesses the state of science and highlights the relevance of the information in a forensic context. Through the different discussions which mark out the review, the potential and limitations of IRMS, as well as the needs and challenges of future studies are emphasized. The paper elicits the various dimensions of the source which can be obtained from the isotope information and demonstrates the transversal nature of IRMS as a tool for source inference. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

A versatile method for simultaneous stable carbon isotope analysis of DNA and RNA nucleotides by liquid chromatography/isotope ratio mass spectrometry

NARCIS (Netherlands)

Moerdijk-Poortvliet, T.C.W.; Brasser, J.; de Ruiter, G.; Houtekamer, M.; Bolhuis, H.; Stal, L.J.; Boschker, H.T.S.

2014-01-01

RATIONALELiquid chromatography/isotope ratio mass spectrometry (LC/IRMS) is currently the most accurate and precise technique for the measurement of compound-specific stable carbon isotope ratios (C-13/C-12) in biological metabolites, at their natural abundance. However, until now this technique

Cross section of W and Z inclusive production and the W/Z cross section ratio in association with one jet for the boson decaying into electron(s) with ATLAS 7 TeV data

CERN Document Server

Berglund, Elina

2011-01-01

This thesis investigates the inclusive production cross section of W and Z bosons as well as their ratio in association with one jet. The cross sections are estimated with 7 TeV LHC proton-proton collision data, collected by ATLAS during 2010, resulting in an integrated luminosity of approximately 40 pb−1 . This thesis focuses on the analysis performed in the electron channel, while comparisons with the results obtained in the muon channel also are included. This is the first time the W and Z production cross sections are measured at this center-of-mass energy and the results are important for various reasons, such as testing perturbative theoretical calculations and understanding these signatures as backgrounds to other physics processes. The final inclusive cross section values obtained in the electron channel are the following: σ(W → eν ) = 10.255 ± 0.031(stat) ± 0.190(syst) ± 0.349(lumi) ± 0.156(acc) nb σ(Z → ee) = 0.952 ± 0.010(stat) ± 0.026(syst) ± 0.032(lumi) ± 0.019(acc) nb The res...

Performance evaluation of indigenous thermal ionization mass spectrometer for determination of 235U/238U atom ratios

International Nuclear Information System (INIS)

Alamelu, D.; Parab, A.R.; Sasi Bhushan, K.; Shah, Raju V.; Jagdish Kumar, S.; Rao, Radhika M.; Aggarwal, S.K.; Bhatia, R.K.; Yadav, V.K.; Sharma, Madhavi P.; Tulsyan, Puneet; Chavda, Pradip; Sriniwasan, P.

2014-07-01

A magnetic sector based Thermal Ionization Mass Spectrometer (TIMS) designed and developed at Technical Physics Division, B.A.R.C., was evaluated for its performance for the determination of 235 U/ 238 U atom ratios in uranium samples. This consisted of evaluating the precision and accuracy on the 235 U/ 238 U atom ratios in various isotopic reference materials as well as indigenously generated uranium samples. The results obtained by the indigenous TIMS were also compared with those obtained using a commercially available TIMS system. The internal and external precision were found to be around 0.1% for determining 235 U/ 238 U atom ratios close to those of natural uranium ( i.e. 0.00730). (author)

Massive graviton dark matter with environment dependent mass: A natural explanation of the dark matter-baryon ratio

Science.gov (United States)

Aoki, Katsuki; Mukohyama, Shinji

2017-11-01

We propose a scenario that can naturally explain the observed dark matter-baryon ratio in the context of bimetric theory with a chameleon field. We introduce two additional gravitational degrees of freedom, the massive graviton and the chameleon field, corresponding to dark matter and dark energy, respectively. The chameleon field is assumed to be nonminimally coupled to dark matter, i.e., the massive graviton, through the graviton mass terms. We find that the dark matter-baryon ratio is dynamically adjusted to the observed value due to the energy transfer by the chameleon field. As a result, the model can explain the observed dark matter-baryon ratio independently from the initial abundance of them.

Mass discrimination

Energy Technology Data Exchange (ETDEWEB)

Broeckman, A. [Rijksuniversiteit Utrecht (Netherlands)

1978-12-15

In thermal ionization mass spectrometry the phenomenon of mass discrimination has led to the use of a correction factor for isotope ratio-measurements. The correction factor is defined as the measured ratio divided by the true or accepted value of this ratio. In fact this factor corrects for systematic errors of the whole procedure; however mass discrimination is often associated just with the mass spectrometer.

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

Science.gov (United States)

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 baryonic antimatter, and it sets a new limit on the gravitational anomaly parameter of |α − 1| < 8.7 × 10(-7).

Association between electronic equipment in the bedroom and sedentary lifestyle, physical activity, and body mass index of children.

Science.gov (United States)

Ferrari, Gerson Luis de Moraes; Araújo, Timóteo Leandro; Oliveira, Luis Carlos; Matsudo, Victor; Fisberg, Mauro

2015-01-01

To describe the association between electronic devices in the bedroom with sedentary time and physical activity, both assessed by accelerometry, in addition to body mass index in children from São Caetano do Sul. The sample consisted of 441 children. The presence of electronic equipment (television, personal computer, and videogames) in the bedroom was assessed by a questionnaire. For seven consecutive days, children used an accelerometer to objectively monitor the sedentary time and moderate-to-vigorous physical activity. Body mass index was categorized as suggested by the World Health Organization. Overall, 73.9%, 54.2% and 42.8% of children had TV, computer, and videogames in the bedroom, respectively, and spent an average of 500.7 and 59.1 min/day of sedentary time and moderate-to-vigorous physical activity. Of the children, 45.3% were overweight/obese. Girls with a computer in the bedroom (45 min/day) performed less moderate-to-vigorous physical activity than those without it (51.4 min/day). Similar results were observed for body mass index in boys. Moderate-to-vigorous physical activity was higher and body mass index was lower in children that had no electronic equipment in the bedroom. Presence of a computer (β=-4.798) and the combination TV+computer (β=-3.233) were negatively associated with moderate-to-vigorous physical activity. Videogames and the combinations with two or three electronic devices were positively associated with body mass index. Sedentary time was not associated with electronic equipment. Electronic equipment in the children's bedroom can negatively affect moderate-to-vigorous physical activity and body mass index regardless of gender, school, and annual family income, which can contribute to physical inactivity and childhood obesity. Copyright © 2015 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

Front-End Electron Transfer Dissociation Coupled to a 21 Tesla FT-ICR Mass Spectrometer for Intact Protein Sequence Analysis

Science.gov (United States)

Weisbrod, Chad R.; Kaiser, Nathan K.; Syka, John E. P.; Early, Lee; Mullen, Christopher; Dunyach, Jean-Jacques; English, A. Michelle; Anderson, Lissa C.; Blakney, Greg T.; Shabanowitz, Jeffrey; Hendrickson, Christopher L.; Marshall, Alan G.; Hunt, Donald F.

2017-09-01

High resolution mass spectrometry is a key technology for in-depth protein characterization. High-field Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) enables high-level interrogation of intact proteins in the most detail to date. However, an appropriate complement of fragmentation technologies must be paired with FTMS to provide comprehensive sequence coverage, as well as characterization of sequence variants, and post-translational modifications. Here we describe the integration of front-end electron transfer dissociation (FETD) with a custom-built 21 tesla FT-ICR mass spectrometer, which yields unprecedented sequence coverage for proteins ranging from 2.8 to 29 kDa, without the need for extensive spectral averaging (e.g., 60% sequence coverage for apo-myoglobin with four averaged acquisitions). The system is equipped with a multipole storage device separate from the ETD reaction device, which allows accumulation of multiple ETD fragment ion fills. Consequently, an optimally large product ion population is accumulated prior to transfer to the ICR cell for mass analysis, which improves mass spectral signal-to-noise ratio, dynamic range, and scan rate. We find a linear relationship between protein molecular weight and minimum number of ETD reaction fills to achieve optimum sequence coverage, thereby enabling more efficient use of instrument data acquisition time. Finally, real-time scaling of the number of ETD reactions fills during method-based acquisition is shown, and the implications for LC-MS/MS top-down analysis are discussed. [Figure not available: see fulltext.

High mass-resolution electron-ion-ion coincidence measurements on core-excited organic molecules

CERN Document Server

Tokushima, T; Senba, Y; Yoshida, H; Hiraya, A

2001-01-01

Total electron-ion-ion coincidence measurements on core excited organic molecules have been carried out with high mass resolution by using multimode (reflectron/linear) time-of-flight mass analyzer. From the ion correlation spectra of core excited CH sub 3 OH and CD sub 3 OH, the reaction pathway to form H sub 3 sup + (D sub 3 sup +) is identified as the elimination of three H (D) atoms from the methyl group, not as the inter-group (-CH sub 3 and -OH) interactions. In a PEPIPICO spectrum of acetylacetone (CH sub 3 COCH sub 2 COCH sub 3) measured by using a reflectron TOF, correlations between ions up to mass number 70 with one-mass resolution was recorded.

Determination of the mass attenuation coefficients for X-ray fluorescence measurements correction by the Rayleigh to Compton scattering ratio

Science.gov (United States)

Conti, C. C.; Anjos, M. J.; Salgado, C. M.

2014-09-01

X-ray fluorescence technique plays an important role in nondestructive analysis nowadays. The development of equipment, including portable ones, enables a wide assortment of possibilities for analysis of stable elements, even in trace concentrations. Nevertheless, despite of the advantages, one important drawback is radiation self-attenuation in the sample being measured, which needs to be considered in the calculation for the proper determination of elemental concentration. The mass attenuation coefficient can be determined by transmission measurement, but, in this case, the sample must be in slab shape geometry and demands two different setups and measurements. The Rayleigh to Compton scattering ratio, determined from the X-ray fluorescence spectrum, provides a link to the mass attenuation coefficient by means of a polynomial type equation. This work presents a way to construct a Rayleigh to Compton scattering ratio versus mass attenuation coefficient curve by using the MCNP5 Monte Carlo computer code. The comparison between the calculated and literature values of the mass attenuation coefficient for some known samples showed to be within 15%. This calculation procedure is available on-line at www.macx.net.br.

Electron contribution to the muon anomalous magnetic moment at four loops

International Nuclear Information System (INIS)

Kurz, Alexander; Liu, Tao; Smirnov, Alexander V.; Smirnov, Vladimir A.; Humboldt-Universitaet, Berlin; Humboldt-Universitaet, Berlin; Steinhauser, Matthias

2016-02-01

We present results for the QED contributions to the anomalous magnetic moment of the muon containing closed electron loops. The main focus is on perturbative corrections at four-loop order where the external photon couples to the external muon. Furthermore, all four-loop contributions involving simultaneously a closed electron and tau loop are computed. In combination with our recent results on the light-by-light-type corrections the complete four-loop electron-loop contribution to the anomalous magnetic moment of the muon has been obtained with an independent calculation. Our calculation is based on an asymptotic expansion in the ratio of the electron and the muon mass and shows the importance of higher order terms in this ratio. We perform a detailed comparison with results available in the literature and find good numerical agreement. As a by-product we present analytic results for the on-shell muon mass and wave function renormalization constants at three-loop order including massive closed electron and tau loops, which we also calculated using the method of asymptotic expansion.

Mass spectrometric investigation of fluorated europium. beta. -diketonates. [Electrons

Energy Technology Data Exchange (ETDEWEB)

Khomenko, V.S.; Lozinskij, M.O.; Fialkov, Yu.A.; Rasshinina, T.A.; Suboch, V.P. (AN Belorusskoj SSR, Minsk. Inst. Fiziki; AN Ukrainskoj SSR, Kiev. Inst. Organicheskoj Khimii)

Ternary complexes of europium with two organic ligands - fluorated ..beta..-diketone and organic base - in the aqueous phase at electron shock are investigated; regroupings that take place in them are established. Mass-spectrometric investigation has shown that complexes with ..beta..-diketones, containing in oxygen atom in a fluorated radical, eliminate stable molecules of difluorophosgen, CoF/sub 2/. For the complexes studied under the above conditions the Co molecule elimination is also typical which is accompanied by the formation of ions with a metal-carbon bond.

Classical electron ionization mass spectra in gas chromatography/mass spectrometry with supersonic molecular beams.

Science.gov (United States)

Gordin, Alexander; Fialkov, Alexander B; Amirav, Aviv

2008-09-01

A major benefit of gas chromatography/mass spectrometry (GC/MS) with a supersonic molecular beam (SMB) interface and its fly-through ion source is the ability to obtain electron ionization of vibrationally cold molecules (cold EI), which show enhanced molecular ions. However, GC/MS with an SMB also has the flexibility to perform 'classical EI' mode of operation which provides mass spectra to mimic those in commercial 70 eV electron ionization MS libraries. Classical EI in SMB is obtained through simple reduction of the helium make-up gas flow rate, which reduces the SMB cooling efficiency; hence the vibrational temperatures of the molecules are similar to those in traditional EI ion sources. In classical EI-SMB mode, the relative abundance of the molecular ion can be tuned and, as a result, excellent identification probabilities and very good matching factors to the NIST MS library are obtained. Classical EI-SMB with the fly-through dual cage ion source has analyte sensitivity similar to that of the standard EI ion source of a basic GC/MS system. The fly-through EI ion source in combination with the SMB interface can serve for cold EI, classical EI-SMB, and cluster chemical ionization (CCI) modes of operation, all easily exchangeable through a simple and quick change (not involving hardware). Furthermore, the fly-through ion source eliminates sample scattering from the walls of the ion source, and thus it offers full sample inertness, tailing-free operation, and no ion-molecule reaction interferences. It is also robust and enables increased column flow rate capability without affecting the sensitivity.

Classifying wine according to geographical origin via quadrupole-based ICP-mass spectrometry measurements of boron isotope ratios

Energy Technology Data Exchange (ETDEWEB)

Coetzee, Paul P. [University of Johannesburg, Department of Chemistry, Johannesburg (South Africa); Vanhaecke, Frank [Institute for Nuclear Sciences, Laboratory of Analytical Chemistry Ghent University, Ghent (Belgium)

2005-11-01

The potential of quadrupole-based ICP-MS as a tool for B-isotopic analysis of wines and its usefulness in provenance determinations were assessed. A precision of 0.1-0.25% RSD (corresponding to a relative standard deviation of the mean of three replicate measurements of 0.06-0.12%) was sufficient to establish small differences in the B isotope ratios in wines from different geographical origins. Each sample measurement was bracketed by measurements of a standard and mass bias drift correction made by interpolation. Sample preparation was kept to a minimum to avoid possible fractionation. Dilution of the wine samples by a factor of 100 with 0.65% HNO{sub 3} was found to reduce matrix-induced mass discrimination substantially. Wines from three wine-producing regions, Stellenbosch, Robertson, and Swartland, in the Western Cape Province of South Africa, and wines from specific regions in France (Bergerac) and Italy (Valpolicella) were analyzed by ICP-QMS for their B-isotopic compositions. It was concluded that the {sup 11}B/{sup 10}B ratios can be used to characterize wines from different geographical origins. Average {sup 11}B/{sup 10}B ratios in red wines from South Africa (Stellenbosch), France (Bergerac), and Italy (Valpolicella) were found to differ by between 0.5 and 1.5%. (orig.)

Classifying wine according to geographical origin via quadrupole-based ICP-mass spectrometry measurements of boron isotope ratios

International Nuclear Information System (INIS)

Coetzee, Paul P.; Vanhaecke, Frank

2005-01-01

The potential of quadrupole-based ICP-MS as a tool for B-isotopic analysis of wines and its usefulness in provenance determinations were assessed. A precision of 0.1-0.25% RSD (corresponding to a relative standard deviation of the mean of three replicate measurements of 0.06-0.12%) was sufficient to establish small differences in the B isotope ratios in wines from different geographical origins. Each sample measurement was bracketed by measurements of a standard and mass bias drift correction made by interpolation. Sample preparation was kept to a minimum to avoid possible fractionation. Dilution of the wine samples by a factor of 100 with 0.65% HNO 3 was found to reduce matrix-induced mass discrimination substantially. Wines from three wine-producing regions, Stellenbosch, Robertson, and Swartland, in the Western Cape Province of South Africa, and wines from specific regions in France (Bergerac) and Italy (Valpolicella) were analyzed by ICP-QMS for their B-isotopic compositions. It was concluded that the 11 B/ 10 B ratios can be used to characterize wines from different geographical origins. Average 11 B/ 10 B ratios in red wines from South Africa (Stellenbosch), France (Bergerac), and Italy (Valpolicella) were found to differ by between 0.5 and 1.5%. (orig.)

Can lifestyle factors explain why body mass index and waist-to-hip ratio increase with increasing tobacco consumption? The Inter99 study

DEFF Research Database (Denmark)

Pisinger, C; Toft, U; Jørgensen, Torben

2009-01-01

BACKGROUND: The relationship between smoking, lifestyle, and weight, body mass index (BMI) and waist-to-hip ratio (WH ratio) is complex, and not fully understood. METHODS: In total, 6784 subjects (2408 daily smokers) were included in a population-based study (the Inter99 study) in Denmark. Weight...... consumption, but these factors did largely explain the increasing WH ratio. The relationship between BMI and tobacco consumption is complex, and the public needs to be informed that smoking is not a 'diet'.......BACKGROUND: The relationship between smoking, lifestyle, and weight, body mass index (BMI) and waist-to-hip ratio (WH ratio) is complex, and not fully understood. METHODS: In total, 6784 subjects (2408 daily smokers) were included in a population-based study (the Inter99 study) in Denmark. Weight...... by sociodemographic factors, rather than lifestyle factors. However, neither sociodemographic nor lifestyle factors could fully explain the increased BMI associated with heavier smoking. CONCLUSIONS: Sociodemographic and lifestyle factors could not fully explain why BMI increased with increasing daily tobacco...

The influence of electron inertia on the modulational instability of ion-acoustic waves

International Nuclear Information System (INIS)

Parkes, E.J.

1993-01-01

The influence of electron inertia, ion streaming and weak relativistic effects on the modulational instability of ion-acoustic waves in a collisionless unmagnetized plasma is investigated. The derivative expansion method is used to derive a nonlinear Schroedinger equation, from which an instability criterion is deduced. When electron inertia is ignored, ion streaming and weak relativistic effects have little effect on the instability criterion. It is shown that when electron inertia is taken into account, the instability criterion is sensitive to weakly relativistic ion streaming, but not to the ratio of electron mass to ion mass. (Author)

Alternative definition of electronic equilibrium: from the analysis of Spencer deduction of the Bragg-Gray cavity theory

International Nuclear Information System (INIS)

Moranchel y Rodriguez, M.; Alvarez R, J.T.

2007-01-01

The definition of the spectral fluence of the electrons used in the Spencer deduction for the Bragg-Gray cavity theory (BG) it assumes the additional condition of electronic equilibrium (EE). Such condition leaves to that the absorbed doses ratio of the means regarding that of the cavity is expressed in function of the total mass stopping power of the means. In this work it is shown that, more that the total mass stopping power should be in function of the collisional mass stopping power of the means, in accordance with the assumed EE condition. As consequence, an expression is obtained for this absorbed dose ratio that it depends exclusively on the collisional mass stopping powers of both means, being a more representative expression of the physical phenomena that happen. Also, an expression for the primary electrons spectral fluence is obtained reflecting thoroughly the physical processes that will give origin to the absorbed dose in the means. Finally, an additional condition for the existence of the EE in function of the fraction of the energy lost by the electrons in the stopping radiation. (Author)

On the interference of Kr during carbon isotope analysis of methane using continuous-flow combustion–isotope ratio mass spectrometry

Directory of Open Access Journals (Sweden)

J. Schmitt

2013-05-01

Full Text Available Stable carbon isotope analysis of methane (δ13C of CH4 on atmospheric samples is one key method to constrain the current and past atmospheric CH4 budget. A frequently applied measurement technique is gas chromatography (GC isotope ratio mass spectrometry (IRMS coupled to a combustion-preconcentration unit. This report shows that the atmospheric trace gas krypton (Kr can severely interfere during the mass spectrometric measurement, leading to significant biases in δ13C of CH4, if krypton is not sufficiently separated during the analysis. According to our experiments, the krypton interference is likely composed of two individual effects, with the lateral tailing of the doubly charged 86Kr peak affecting the neighbouring m/z 44 and partially the m/z 45 Faraday cups. Additionally, a broad signal affecting m/z 45 and especially m/z 46 is assumed to result from scattered ions of singly charged krypton. The introduced bias in the measured isotope ratios is dependent on the chromatographic separation, the krypton-to-CH4 mixing ratio in the sample, the focusing of the mass spectrometer as well as the detector configuration and can amount to up to several per mil in δ13C. Apart from technical solutions to avoid this interference, we present correction routines to a posteriori remove the bias.

A model explaining neutrino masses and the DAMPE cosmic ray electron excess

DEFF Research Database (Denmark)

Fan, Yi Zhong; Huang, Wei Chih; Spinrath, Martin

2018-01-01

We propose a flavored U(1)eμ neutrino mass and dark matter (DM) model to explain the recent DArk Matter Particle Explorer (DAMPE) data, which feature an excess on the cosmic ray electron plus positron flux around 1.4 TeV. Only the first two lepton generations of the Standard Model are charged under...... the new U(1)eμ gauge symmetry. A vector-like fermion ψ, which is our DM candidate, annihilates into e± and μ± via the new gauge boson Z′ exchange and accounts for the DAMPE excess. We have found that the data favors a ψ mass around 1.5 TeV and a Z′ mass around 2.6 TeV, which can potentially be probed...

Total homocysteine is positively correlated with body mass index, waist-to-hip ratio, and fat mass among overweight reproductive women: A cross-sectional study.

Science.gov (United States)

Al-Bayyari, Nahla; Hamadneh, Jehan; Hailat, Rae'd; Hamadneh, Shereen

2017-12-01

Conflicting associations between total homocysteine (tHcy), body mass index (BMI) lean body mass, and fat mass in the general population have been reported. We investigated the hypothesis that elevated tHcy levels are associated with increased BMI, waist-to-hip ratio (WHR), and body fat mass percent. In Jordan, obesity and overweight are prevalent among reproductive women and hyperhomocysteinemia, along with obesity and overweight, are independent risk factors for cardiovascular diseases. The participants used in this cross-sectional study were 325 overweight Jordanian women aged between 18 and 49 years old. The main outcome measures were tHcy, BMI, WHR, fat mass, fat-free mass, and total body water. Serum tHcy was analyzed using a liquid chromatography tandem mass spectrophotometry (LC-MS/MS) complete kit. The body compositions were measured using a bioelectrical impedance analyzer. Study participants were stratified according to their tHcy level into two groups, ≤10 μmol/L and >10 μmol/L, and the difference between mean values of body compositions was evaluated. The tHcy was significantly and negatively correlated with age, fat-free mass, and total body water, and significantly and positively correlated with BMI, hip circumference, WHR, fat mass, and dry lean weight. The chi-square and the independent sample t-tests showed statistically significant (P ≤ .05) differences between tHcy and BMI, WHR, fat and fat-free mass, and total body water percentages. In conclusion, BMI, WHR and body fat mass were found to be associated with elevated tHcy levels among overweight reproductive women, and they might be used as independent predictors of the tHcy level. Copyright © 2017 Elsevier Inc. All rights reserved.

Isochoric heating of reduced mass targets by ultra-intense laser produced relativistic electrons

Energy Technology Data Exchange (ETDEWEB)

Neumayer, P; Lee, H J; Offerman, D; Shipton, E; Kemp, A; Kritcher, A L; Doppner, T; Back, C A; Glenzer, S H

2009-02-04

We present measurements of the chlorine K-alpha emission from reduced mass targets, irradiated with ultra-high intensity laser pulses. Chlorinated plastic targets with diameters down to 50 micrometers and mass of a few 10{sup -8} g were irradiated with up to 7 J of laser energy focused to intensities of several 10{sup 19} W/cm{sup 2}. The conversion of laser energy to K-alpha radiation is measured, as well as high resolution spectra that allow observation of line shifts, indicating isochoric heating of the target up to 18 eV. A zero-dimensional 2-temperature equilibration model, combined with electron impact K-shell ionization and post processed spectra from collisional radiative calculations reproduces the observed K-alpha yields and line shifts, and shows the importance of target expansion due to the hot electron pressure.

Hydrogenation of organic matter as a terminal electron sink sustains high CO 2 :CH 4 production ratios during anaerobic decomposition

Energy Technology Data Exchange (ETDEWEB)

Wilson, Rachel M.; Tfaily, Malak M.; Rich, Virginia I.; Keller, Jason K.; Bridgham, Scott D.; Zalman, Cassandra Medvedeff; Meredith, Laura; Hanson, Paul J.; Hines, Mark; Pfeifer-Meister, Laurel; Saleska, Scott R.; Crill, Patrick; Cooper, William T.; Chanton, Jeff P.; Kostka, Joel E.

2017-10-01

Once inorganic electron acceptors are depleted, organic matter in anoxic environments decomposes by hydrolysis, fermentation, and methanogenesis, requiring syntrophic interactions between microorganisms to achieve energetic favorability. In this classic anaerobic food chain, methanogenesis represents the terminal electron accepting (TEA) process, ultimately producing equimolar CO2 and CH4 for each molecule of organic matter degraded. However, CO2:CH4 production in Sphagnum-derived, mineral-poor, cellulosic peat often substantially exceeds this 1:1 ratio, even in the absence of measureable inorganic TEAs. Since the oxidation state of C in both cellulose-derived organic matter and acetate is 0, and CO2 has an oxidation state of +4, if CH4 (oxidation state -4) is not produced in equal ratio, then some other compound(s) must balance CO2 production by receiving 4 electrons. Here we present evidence for ubiquitous hydrogenation of diverse unsaturated compounds that appear to serve as organic TEAs in peat, thereby providing the necessary electron balance to sustain CO2:CH4 >1. While organic electron acceptors have previously been proposed to drive microbial respiration of organic matter through the reversible reduction of quinone moieties, the hydrogenation mechanism that we propose, by contrast, reduces C-C double bonds in organic matter thereby serving as 1) a terminal electron sink, 2) a mechanism for degrading complex unsaturated organic molecules, 3) a potential mechanism to regenerate electron-accepting quinones, and, in some cases, 4) a means to alleviate the toxicity of unsaturated aromatic acids. This mechanism for CO2 generation without concomitant CH4 production has the potential to regulate the global warming potential of peatlands by elevating CO2:CH4 production ratios.

Calorimetric measurements of $^{163}$ holmium decay as tools to determine the electron neutrino mass

CERN Document Server

De Rújula, Alvaro

1982-01-01

Computes the spectrum of 'calorimetric' energy in the electron capture decay of /sup 163/Ho. A calorimetric experiment would yield an excellent determination of (/sup 163/Ho, /sup 163/Dy) mass difference. The proximity of the spectral endpoint to an atomic resonance makes the fraction of events that are sensitive to a non-zero neutrino mass superior in /sup 163/Ho decay than in tritium decay.

Some major deviations for biomass determination by indirect method and estimation based on alkali consumption. [Ratio of cell mass produced and alkali consumed; diesel fuel culture medium

Energy Technology Data Exchange (ETDEWEB)

Concone, B R.V.; Doin, P A; Pinto, A G

1978-01-01

Some factors like the variation of the liquid volume, the variation of cellular nitrogen content and the mass of cells taken with the samples during batch cultivation of microorganisms on diesel oil, were considered for the computation of the ratio between cell mass produced and the mass of alkali consumed to maintain constant the pH of the fermentation medium. The results obtained showed that if such ratios are computed with cell concentration instead of cell mass the deviations can be of the order of 27% caused by the variation of the liquid medium volume. Otherwise, the results showed also that those ratios are variable during batch cultivation on diesel oil probably because of the variations on the nitrogen content of microorganisms. The relative difference between the mass of cells measured and the mass of cells calculated from the alkali consumption curve can be of the order of 63%.

Determination of δ13C, δ15N, or δ34S by isotope-ratio-monitoring mass spectrometry using an elemental analyzer

Science.gov (United States)

Johnson, Craig A.; Stricker, Craig A.; Gulbransen, Cayce A.; Emmons, Matthew P.

2018-02-14

This report describes procedures used in the Geology, Geophysics, and Geochemistry Science Center of the U.S. Geological Survey in Denver, Colorado, to determine the stable-isotope ratios 13C/12C, 15N/14N, and 34S/32S in solid materials. The procedures use elemental analyzers connected directly to gas-source isotope-ratio mass spectrometers. A different elemental–analyzer–mass-spectrometer system is used for 13C/12C and 15N/14N than is used for 34S/32S to accommodate differences in reagents, catalysts, and instrument settings.

Reduction of combinatorical background in the mass spectrum of electron pairs

International Nuclear Information System (INIS)

Tonse, S.

1992-01-01

Among the aims of the PHENIX experiment are the identification and measurement of the properties of the ρ, ω, φ and J/ψ vector mesons that have decayed through the e + e - channel. The main obstacle to identifying vector mesons (VM) using the e + e - invariant mass, is the significant number of e + and e - from other sources, which causes a large combinatorical background in the invariant mass spectrum. The work we have done aims to reduce this background by identifying background sources through kinematical cuts and removing them along with their combinatorical effects, while at the same time preserving as much as possible of the signal, i.e. the electrons from VM decay. A measurement of electron pairs (e + and e - ) from π-π and q bar q thermal sources is also a possibility, and a clear identification of the ''easier'' vector mesons (ω, φ) will be an indication of how well the thermal measurement can be done. To determine the nature and values of the kinematical cuts we have used a computer simulation to generate particles according to predetermined phase-space (rapidity and P T ) and multiplicity distributions

New mass spectrometers for hydrogen isotope analyses

International Nuclear Information System (INIS)

Chastagner, P.; Daves, H.L.; Hess, W.B.

1981-01-01

Two advanced mass spectrometers for the accurate analysis of mixtures of the hydrogen isotopes are being evaluated by Du Pont personnel at the Savannah River Laboratory. One is a large double-focusing instrument with a resolution of 2000 at mass 4, an abundance sensitivity of > 100,000 for the HT-D 2 doublet, and a sophisticated electronic control and data collection system. The second is a smaller, simpler, stigmatic-focusing instrument in which exceptionally high ion intensities (> 1 x 10 -9 A) result in high signal to noise ratios. A containment facility with sample inlet systems and a standard distribution system was built to permit testing with tritium mixtures. The characteristics of the mass spectrometers under a variety of operating conditions will be presented. Factors to be discussed include: sample equilibration and its elimination; linearity; trimer formation; gas interference; stability; signal to noise ratio; mass discrimination; and anticipated precision and accu sublimed molybdenum collector of Converter No. 262; and (3) demonstration of tungsten CVD onto molybdenum flange using a reuseable graphite mandrel

Delta-electron spectroscopy: An aid for the determination of reaction times in heavy ion reactions

International Nuclear Information System (INIS)

Skapa, H.

1983-01-01

For the systems I->Au and I->Bi at an incident energy of 6.2 MeV/u (I->Au) and 6.6 MeV/u (I->Bi) the emission probability of delta electrons was determined. In an energy range from 150 KeV to 1000 KeV electrons were spectroscoped in coincidence to elastically, quasielastically, and deep inelastically scattered ions. In deep inelastic reaction between reaction products with high and without a mean mass drift was discriminated. The contribution of the conversion electrons, determined from gamma spectra, extends in the range of deep inelastic reactions of about 60%. While the ratio of conversion electrons for deep inelastic events with large to such without mass drift shows a flat, monotoneous growth for the ratio of the measured emission probabilities a oscillation-like structure with about 400 KeV width results. An interpretation of this structure as interference effect by nuclear time delay yields for the case of large mass drift a nuclear retention time of 7.5 x 10 -21 s. (orig./HSI) [de

Electron Mobilities and Effective Masses in InGaAs/InAlAs HEMT Structures with High In Content

Science.gov (United States)

Yuzeeva, N. A.; Sorokoumova, A. V.; Lunin, R. A.; Oveshnikov, L. N.; Galiev, G. B.; Klimov, E. A.; Lavruchin, D. V.; Kulbachinskii, V. A.

2016-12-01

InxGa_{1-{x}}As/InyAl_{1-{y}}As HEMT structures {δ}-doped by Si were grown by molecular beam epitaxy on InP substrate. We investigated the influence of the In content on the electron mobilities and effective masses in dimensionally quantized subbands. The electron effective masses were determined by the temperature dependence of the amplitude of the Shubnikov-de Haas effect at 1.6 and 4.2 K. We found that the more the In content in quantum well (QW), the less the electron effective masses. The mobilities are higher in HEMT structures with wider and deeper QW. The energy band diagrams were calculated by using Vegard's law for basic parameters. The calculated band diagrams are in a good agreement with the experimental data of photoluminescence spectra.

Limb/trunk lean mass ratio as a risk factor for mortality in peritoneal dialysis patients

Directory of Open Access Journals (Sweden)

Seok Hui Kang

2012-06-01

Full Text Available Protein energy wasting (PEW is a common problem in dialysis patients. There have been few reports on the effects of regional lean mass distribution for peritoneal dialysis (PD patients. We reviewed the medical records and identified all adults who received PD between May 2001 and May 2011. Five hundred thirty four patients were enrolled. The clinical and laboratory data were collected at 1 and 12 months. Regional lean masses were measured by dual-energy X-ray absorptiometry. The limb/trunk lean mass ratio (LTLM was defined as a value on dividing the sum of four limbs by the trunk lean mass. The mean age at the start of PD was 53.2±14.1 years. Diabetes mellitus (DM was most common underlying disease of end-stage renal disease (49.6%. In males, the low LTLM tertile was associated with low body mass index, creatinine, arm muscle circumference, and high C-reactive protein. In females, the low LTLM tertile was associated with low creatinine and normalized protein equivalent of nitrogen appearance. On both univariate and multivariate analysis adjusted for age, Davies risk index, and residual renal function, initial low LTLM tertile and maintenance of low LTLM were associated with mortality in PD patients. Distribution or change of regional lean mass may be more useful for predicting nutritional status. Initial low LTLM and maintenance of low LTLM were associated with mortality in PD patients. LTLM as a new marker would be useful for predicting the nutritional status and the mortality in patients on PD.

Determination of the mass attenuation coefficients for X-ray fluorescence measurements correction by the Rayleigh to Compton scattering ratio

Energy Technology Data Exchange (ETDEWEB)

Conti, C.C., E-mail: ccconti@ird.gov.br [Institute for Radioprotection and Dosimetry – IRD/CNEN, Rio de Janeiro (Brazil); Physics Institute, State University of Rio de Janeiro – UERJ, Rio de Janeiro (Brazil); Anjos, M.J. [Physics Institute, State University of Rio de Janeiro – UERJ, Rio de Janeiro (Brazil); Salgado, C.M. [Nuclear Engineering Institute – IEN/CNEN, Rio de Janeiro (Brazil)

2014-09-15

Highlights: •This work describes a procedure for sample self-absorption correction. •The use of Monte Carlo simulation to calculate the mass attenuation coefficients curve was effective. •No need for transmission measurement, saving time, financial resources and effort. •This article provides de curves for the 90° scattering angle. •Calculation on-line at (www.macx.net.br). -- Abstract: X-ray fluorescence technique plays an important role in nondestructive analysis nowadays. The development of equipment, including portable ones, enables a wide assortment of possibilities for analysis of stable elements, even in trace concentrations. Nevertheless, despite of the advantages, one important drawback is radiation self-attenuation in the sample being measured, which needs to be considered in the calculation for the proper determination of elemental concentration. The mass attenuation coefficient can be determined by transmission measurement, but, in this case, the sample must be in slab shape geometry and demands two different setups and measurements. The Rayleigh to Compton scattering ratio, determined from the X-ray fluorescence spectrum, provides a link to the mass attenuation coefficient by means of a polynomial type equation. This work presents a way to construct a Rayleigh to Compton scattering ratio versus mass attenuation coefficient curve by using the MCNP5 Monte Carlo computer code. The comparison between the calculated and literature values of the mass attenuation coefficient for some known samples showed to be within 15%. This calculation procedure is available on-line at (www.macx.net.br)

Two types of the effective mass divergence and the Grueneisen ratio in heavy-fermion metals

International Nuclear Information System (INIS)

Amusia, M.Ya.; Msezane, A.Z.; Shaginyan, V.R.

2004-01-01

The behavior of the specific heat c p , effective mass M*, and the thermal expansion coefficient α of a Fermi system located near the fermion condensation quantum phase transition (FCQPT) is considered. We observe the first type behavior if the system is close to FCQPT: the specific heat c p ∝√T, M*∝1/√T, while the thermal expansion coefficient α∝√T. Thus, the Grueneisen ratio Γ(T)=α/c p does not diverges. At the transition region, where the system passes over from the non-Fermi liquid to the Landau Fermi liquid, the ratio diverges as Γ(T)∝1/√T. In the system becomes the Landau Fermi liquid, Γ(T,r)∝1/r, with r being a distance from the quantum critical point. Provided the system has undergone FCQPT, the second type takes place: the specific heat behaves as c p ∝√T, M * ∝1/T, and α=a+bT with a,b being constants. Again, the Grueneisen ratio diverges as Γ(T)∝1/√T

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

International Nuclear Information System (INIS)

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

2010-01-01

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 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 14 C/C ratio, independent of chemical separation procedures. The isotope ratio measurement was specific (owing to the 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 14 C corresponds to 30 fg equivalents. AMS

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

Energy Technology Data Exchange (ETDEWEB)

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

A model explaining neutrino masses and the DAMPE cosmic ray electron excess

Science.gov (United States)

Fan, Yi-Zhong; Huang, Wei-Chih; Spinrath, Martin; Tsai, Yue-Lin Sming; Yuan, Qiang

2018-06-01

We propose a flavored U(1)eμ neutrino mass and dark matter (DM) model to explain the recent DArk Matter Particle Explorer (DAMPE) data, which feature an excess on the cosmic ray electron plus positron flux around 1.4 TeV. Only the first two lepton generations of the Standard Model are charged under the new U(1)eμ gauge symmetry. A vector-like fermion ψ, which is our DM candidate, annihilates into e± and μ± via the new gauge boson Z‧ exchange and accounts for the DAMPE excess. We have found that the data favors a ψ mass around 1.5 TeV and a Z‧ mass around 2.6 TeV, which can potentially be probed by the next generation lepton colliders and DM direct detection experiments.

Indigenous instrumentation for mass spectrometry. PD-5-1

International Nuclear Information System (INIS)

Handu, V.K.

2007-01-01

Mass Spectrometry is a powerful analytical technique due to its high sensitivity, specificity, selectivity, and wide field of applications in elemental analysis, especially in the determination of trace and ultra trace elements, precise and accurate isotopic ratio measurements. Due to these excellent features, it is a crucial analytical tool for number of Department of Atomic Energy's (DAE) programs. BARC, over the years, has developed several mass spectrometers suitable for needs of a number of programs in DAE and, in this process, technologies have been developed in HV/UHV systems, precision mechanical engineering and fabrication, design and fabrication of electromagnets, ion optics, ultra stable analog and digital electronics, data systems etc. A large number of these mass spectrometers are being used regularly in various units of DAE. Since users are demanding TIMS mass spectrometer with better specifications, efforts are being made in house to develop TIMS with improved specifications. Efforts are also under way to develop a multi collector, plasma source mass spectrometer (MC-ICP-MS) with magnetic sector mass analyzer, since such instrument is increasingly being used to measure isotopic ratios with high precision

Determination of the Isotope Ratio for Metal Samples Using a Laser Ablation/Ionization Time-of-flight Mass Spectrometry

International Nuclear Information System (INIS)

Song, Kyu Seok; Cha, Hyung Ki; Kim, Duk Hyeon; Min, Ki Hyun

2004-01-01

The laser ablation/ionization time-of-flight mass spectrometry is applied to the isotopic analysis of solid samples using a home-made instrument. The technique is convenient for solid sample analysis due to the onestep process of vaporization and ionization of the samples. The analyzed samples were lead, cadmium, molybdenum, and ytterbium. To optimize the analytical conditions of the technique, several parameters, such as laser energy, laser wavelength, size of the laser beam on the samples surface, and high voltages applied on the ion source electrodes were varied. Low energy of laser light was necessary to obtain the optimal mass resolution of spectra. The 532 nm light generated mass spectra with the higher signal-to-noise ratio compared with the 355 nm light. The best mass resolution obtained in the present study is ∼1,500 for the ytterbium

Novel method for measurement of glutathione kinetics in neonates using liquid chromatography coupled to isotope ratio mass spectrometry

NARCIS (Netherlands)

Schierbeek, Henk; te Braake, Frans; Godin, Jean-Philippe; Fay, Laurent-Bernard; van Goudoever, Johannes B.

2007-01-01

A novel analytical method using liquid chromatography coupled to isotope ratio mass spectrometry (LC/IRMS) was developed for measuring the fractional synthesis rate (FSR) of glutathione (GSH) in neonates after infusion of [1-(13)C]-glycine as a tracer. After transformation of GSH into GSSG, its

Ratio of Dietary n-6/n-3 Polyunsaturated Fatty Acids Independently Related to Muscle Mass Decline in Hemodialysis Patients.

Directory of Open Access Journals (Sweden)

Te-Chih Wong

Full Text Available 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.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.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.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.

Ratio of Dietary n-6/n-3 Polyunsaturated Fatty Acids Independently Related to Muscle Mass Decline in Hemodialysis Patients.

Science.gov (United States)

Wong, Te-Chih; Chen, Yu-Tong; Wu, Pei-Yu; Chen, Tzen-Wen; Chen, Hsi-Hsien; Chen, Tso-Hsiao; Yang, Shwu-Huey

2015-01-01

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. 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. 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. 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.

Two improvements on numerical simulation of 2-DOF vortex-induced vibration with low mass ratio

Science.gov (United States)

Kang, Zhuang; Ni, Wen-chi; Zhang, Xu; Sun, Li-ping

2017-12-01

Till now, there have been lots of researches on numerical simulation of vortex-induced vibration. Acceptable results have been obtained for fixed cylinders with low Reynolds number. However, for responses of 2-DOF vortex-induced vibration with low mass ratio, the accuracy is not satisfactory, especially for the maximum amplitudes. In Jauvtis and Williamson's work, the maximum amplitude of the cylinder with low mass ratio m*=2.6 can reach as large as 1.5 D to be called as the "super-upper branch", but from current literatures, few simulation results can achieve such value, even fail to capture the upper branch. Besides, it is found that the amplitude decays too fast in the lower branch with the RANS-based turbulence model. The reason is likely to be the defects of the turbulence model itself in the prediction of unsteady separated flows as well as the unreasonable setting of the numerical simulation parameters. Aiming at above issues, a modified turbulence model is proposed in this paper, and the effect of the acceleration of flow field on the response of vortex-induced vibration is studied based on OpenFOAM. By analyzing the responses of amplitude, phase and trajectory, frequency and vortex mode, it is proved that the vortex-induced vibration can be predicted accurately with the modified turbulence model under appropriate flow field acceleration.

Acculturation and changes in body mass index, waist circumference, and waist-hip ratio among Filipino Americans with hypertension.

Science.gov (United States)

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 stress the importance of the degree of acculturation when developing culturally appropriate lifestyle and health promotion interventions among immigrant patients with hypertension. Copyright © 2016 American Society of Hypertension. Published by Elsevier Inc. All rights reserved.

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

Science.gov (United States)

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

Fractionation and Characterization of High Aspect Ratio Gold Nanorods Using Asymmetric-Flow Field Flow Fractionation and Single Particle Inductively Coupled Plasma Mass Spectrometry

Directory of Open Access Journals (Sweden)

Thao M. Nguyen

2015-07-01

Full Text Available Gold nanorods (GNRs are of particular interest for biomedical applications due to their unique size-dependent longitudinal surface plasmon resonance band in the visible to near-infrared. Purified GNRs are essential for the advancement of technologies based on these materials. Used in concert, asymmetric-flow field flow fractionation (A4F and single particle inductively coupled mass spectrometry (spICP-MS provide unique advantages for fractionating and analyzing the typically complex mixtures produced by common synthetic procedures. A4F fractions collected at specific elution times were analyzed off-line by spICP-MS. The individual particle masses were obtained by conversion of the ICP-MS pulse intensity for each detected particle event, using a defined calibration procedure. Size distributions were then derived by transforming particle mass to length assuming a fixed diameter. The resulting particle lengths correlated closely with ex situ transmission electron microscopy. In contrast to our previously reported observations on the fractionation of low-aspect ratio (AR GNRs (AR < 4, under optimal A4F separation conditions the results for high-AR GNRs of fixed diameter (≈20 nm suggest normal, rather than steric, mode elution (i.e., shorter rods with lower AR generally elute first. The relatively narrow populations in late eluting fractions suggest the method can be used to collect and analyze specific length fractions; it is feasible that A4F could be appropriately modified for industrial scale purification of GNRs.

Electron effective mass in Sn-doped monoclinic single crystal β-gallium oxide determined by mid-infrared optical Hall effect

Science.gov (United States)

Knight, Sean; Mock, Alyssa; Korlacki, Rafał; Darakchieva, Vanya; Monemar, Bo; Kumagai, Yoshinao; Goto, Ken; Higashiwaki, Masataka; Schubert, Mathias

2018-01-01

The isotropic average conduction band minimum electron effective mass in Sn-doped monoclinic single crystal β-Ga2O3 is experimentally determined by the mid-infrared optical Hall effect to be (0.284 ± 0.013)m0 combining investigations on (010) and ( 2 ¯01 ) surface cuts. This result falls within the broad range of values predicted by theoretical calculations for undoped β-Ga2O3. The result is also comparable to recent density functional calculations using the Gaussian-attenuation-Perdew-Burke-Ernzerhof hybrid density functional, which predict an average effective mass of 0.267m0. Within our uncertainty limits, we detect no anisotropy for the electron effective mass, which is consistent with most previous theoretical calculations. We discuss upper limits for possible anisotropy of the electron effective mass parameter from our experimental uncertainty limits, and we compare our findings with recent theoretical results.

Measurement of the semi-leptonic and hadronic branching ratios and mass of Bs0 with the ALEPH detector at LEP

International Nuclear Information System (INIS)

Nief, Jean-Yves

1997-01-01

Since the discovery of the b quark in 1977 the physics of the beauty has known an important development. Among the main aspects of this field, one can find the measurement of the branching ratios and the mass of the beauty mesons. This study allows a confrontation between the experimental results on one hand and predictions given by phenomenological models on the other hand. This thesis is dedicated to the study of the B s 0 meson, which contains both a beauty quark and a strange quark. This analysis uses 4 millions hadronic events taken by the ALEPH experiment between 1991 and 1995 on the electron-positron collider LEP located at CERN. From these events the B s 0 meson is searched in two types of decays: semi-leptonic and hadronic decays. This study allows to extract various branching ratios of B s 0 . From the fully reconstructed candidates in the hadronic channels a measurement of the B s 0 is carried out. The measurements are in agreement with the predictions of the phenomenological models available at present. This thesis is also on the tracking and identification upgrade of the charged particles in the ALEPH detector, especially the Kalman Filter (tracking part) at a complementary measurement of the specific ionization, dE/dx (identification part). Tests carried out in the field of B d 0 semi-leptonic decays shows that these improvements will be rewarding in the future. (author)

Determination of 240Pu/239Pu isotope ratios in Kara Sea and Novaya Zemlya sediments using accelerator mass spectrometry

International Nuclear Information System (INIS)

Oughton, D.H.; Skipperud, L.; Salbu, B.; Fifield, L.K.; Cresswell, R.C.; Day, J.P.

1999-01-01

Accelerator mass spectrometry (AMS) has been used to determine Pu activity concentrations and 240 Pu/ 239 Pu isotope ratios in sediments from the Kara Sea and radioactive waste dumping sites at Novaya Zemlya. Measured 239,240 Pu activities ranged from 0.06 - 9.8 Bq/kg dry weight, 240 Pu/ 239 Pu atom ratios ranged from 0.13 to 0.28, and 238 Pu/ 239,240 Pu activity ratios from 0.02 to 0.6. Perturbations from global fallout isotope ratios were evident at three sites: the Yenisey Estuary and Abrosimov Fjords where 240 Pu/ 239 Pu ratios were lower (0.13-0.14); and Stepovogo Fjord sediments where ratios were higher (up to 0.28) than fallout ratios. Based on procedural blanks, detection limits for AMS were below 1 fg Pu and the method showed good precision for isotope ratio measurements, minimal matrix, interference and memory effects. For high level samples, comparison between alpha spectrometry and AMS gave good agreement for measurement of 239,240 Pu activity concentrations. (author)

Continuous-flow isotope ratio mass spectrometry method for carbon and hydrogen isotope measurements on atmospheric methane

Directory of Open Access Journals (Sweden)

M. Brass

2010-12-01

Full Text Available We describe a continuous-flow isotope ratio mass spectrometry (CF-IRMS technique for high-precision δD and δ¹³C measurements of atmospheric methane on 40 mL air samples. CH₄ is separated from other air components by utilizing purely physical processes based on temperature, time and mechanical valve switching. Chemical agents are avoided. Trace amounts of interfering compounds can be separated by gas chromatography after pre-concentration of the CH₄ sample. The purified sample is then either combusted to CO₂ or pyrolyzed to H₂ for stable isotope measurement. Apart from connecting samples and refilling liquid nitrogen as coolant the system is fully automated and allows an unobserved, continuous analysis of samples. The analytical system has been used for analysis of air samples with CH₄ mixing ratios between ~100 and ~10 000 ppb, for higher mixing ratios samples usually have to be diluted.

Photodetachment of electron of polyanions: fundamental aspects and application to mass spectrometry

International Nuclear Information System (INIS)

Brunet, Claire

2012-01-01

This research thesis reports a study of optical properties and of photo-fragmentation of proteins in gas phase. After an overview of the different techniques of fragmentation and optical spectroscopy used for the characterisation of proteins, the author presents the experimental apparatus which implements a coupling of optical spectroscopy (UV/visible laser) and mass spectrometry (LTQ, linear trap quadrupole). Then, she reports the structural characterisation of proteins for a large range of wavelength (from UV to visible), and the study of the properties of the electron emitted by the measurement of its kinetic energy by photo-electron spectroscopy. She shows that the UV-visible radiation can also be used to study optical properties of radical anions by means of an experimental installation with two colours. The last part addresses the technique of dissociation by electron photodetachment which is notably compared with dissociation by electron detachment on a set of peptides of different sizes and negatively charged. The complementarity of these both techniques is discussed [fr

Auger electron spectroscopy for the determination of sex and age related Ca/P ratio at different bone sites

International Nuclear Information System (INIS)

Balatsoukas, Ioannis; Kourkoumelis, Nikolaos; Tzaphlidou, Margaret

2010-01-01

The Ca/P ratio of normal cortical and trabecular rat bone was measured by Auger electron spectroscopy (AES). Semiquantitative analysis was carried out using ratio techniques to draw conclusions on how age, sex and bone site affect the relative composition of calcium and phosphorus. Results show that Ca/P ratio is not sex dependent; quite the opposite, bone sites exhibit variations in elemental stoichiometry where femoral sections demonstrate higher Ca/P ratio than rear and front tibias. Age-related changes are more distinct for cortical bone in comparison with the trabecular bone. The latter's Ca/P ratio remains unaffected from all the parameters under study. This study confirms that AES is able to successfully quantify bone mineral main elements when certain critical points, related to the experimental conditions, are addressed effectively.

A new time of flight mass spectrometer for absolute dissociative electron attachment cross-section measurements in gas phase

Science.gov (United States)

Chakraborty, Dipayan; Nag, Pamir; Nandi, Dhananjay

2018-02-01

A new time of flight mass spectrometer (TOFMS) has been developed to study the absolute dissociative electron attachment (DEA) cross section using a relative flow technique of a wide variety of molecules in gas phase, ranging from simple diatomic to complex biomolecules. Unlike the Wiley-McLaren type TOFMS, here the total ion collection condition has been achieved without compromising the mass resolution by introducing a field free drift region after the lensing arrangement. The field free interaction region is provided for low energy electron molecule collision studies. The spectrometer can be used to study a wide range of masses (H- ion to few hundreds atomic mass unit). The mass resolution capability of the spectrometer has been checked experimentally by measuring the mass spectra of fragment anions arising from DEA to methanol. Overall performance of the spectrometer has been tested by measuring the absolute DEA cross section of the ground state SO2 molecule, and the results are satisfactory.

Ratios of regioisomers of minor acylglycerols less polar than triricinolein in castor oil estimated by mass spectrometry (Abstract)

Science.gov (United States)

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...

CROSS-CORRELATION WEAK LENSING OF SDSS GALAXY CLUSTERS. III. MASS-TO-LIGHT RATIOS

International Nuclear Information System (INIS)

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

2009-01-01

We present measurements of the excess mass-to-light ratio (M/L) measured around MaxBCG galaxy clusters observed in the Sloan Digital Sky Survey. This red-sequence cluster sample includes objects from small groups with M 200 ∼ 5 x 10 12 h -1 M sun to clusters with M 200 ∼ 10 15 h -1 M sun . Using cross-correlation weak lensing, we measure the excess mass density profile above the universal mean Δρ(r)=ρ(r)-ρ-bar for clusters in bins of richness and optical luminosity. We also measure the excess luminosity density Δl(r)=l(r)-l-bar measured in the z = 0.25 i band. For both mass and light, we de-project the profiles to produce three-dimensional mass and light profiles over scales from 25 h -1 kpc to 22 h -1 Mpc. From these profiles we calculate the cumulative excess mass ΔM(r) and excess light ΔL(r) as a function of separation from the BCG. On small scales, where ρ(r)>>ρ-bar, the integrated mass-to-light profile (ΔM/ΔL)(r) may be interpreted as the cluster M/L. We find the (ΔM/ΔL) 200 , the M/L within r 200 , scales with cluster mass as a power law with index 0.33 ± 0.02. On large scales, where ρ(r)∼ρ-bar, the ΔM/ΔL approaches an asymptotic value independent of cluster richness. For small groups, the mean (ΔM/ΔL) 200 is much smaller than the asymptotic value, while for large clusters (ΔM/ΔL) 200 is consistent with the asymptotic value. This asymptotic value should be proportional to the mean M/L of the universe (M/L). We find (M/L)b -2 M/L = 362 ± 54h (statistical). There is additional uncertainty in the overall calibration at the ∼10% level. The parameter b 2 M/L is primarily a function of the bias of the L ∼ * galaxies used as light tracers, and should be of order unity. Multiplying by the luminosity density in the same bandpass we find Ω m b -2 M/L = 0.20 ± 0.03, independent of the Hubble parameter.

Electron density profile measurements from hydrogen line intensity ratio method in Versatile Experimental Spherical Torus

Energy Technology Data Exchange (ETDEWEB)

Kim, YooSung; Shi, Yue-Jiang, E-mail: yjshi@snu.ac.kr; Yang, Jeong-hun; Kim, SeongCheol; Kim, Young-Gi; Dang, Jeong-Jeung; Yang, Seongmoo; Jo, Jungmin; Chung, Kyoung-Jae [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Oh, Soo-Ghee [Division of Energy Systems Research, Ajou University, Suwon 442-749 (Korea, Republic of); Hwang, Y. S. [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Center for Advanced Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)

2016-11-15

Electron density profiles of versatile experiment spherical torus plasmas are measured by using a hydrogen line intensity ratio method. A fast-frame visible camera with appropriate bandpass filters is used to detect images of Balmer line intensities. The unique optical system makes it possible to take images of H{sub α} and H{sub β} radiation simultaneously, with only one camera. The frame rate is 1000 fps and the spatial resolution of the system is about 0.5 cm. One-dimensional local emissivity profiles have been obtained from the toroidal line of sight with viewing dumps. An initial result for the electron density profile is presented and is in reasonable agreement with values measured by a triple Langmuir probe.

Long-term orbital period behaviour of low mass ratio contact binaries GR Vir and FP Boo

Science.gov (United States)

Ćetinkaya, Halil; Soydugan, Faruk

2017-02-01

In this study, we investigated orbital period variations of two low mass ratio contact binaries GR Vir and FP Boo based on published minima times. From the O-C analysis, it was found that FP Boo indicates orbital period decrease while the period of GR Vir is increasing. Mass transfer process was used to explain increase and decrease in the orbital periods. In the O-C diagrams of both systems periodic variations also exist. Cyclic changes can be explained as being the result of a light-travel time effect via a third component around the eclipsing binaries. In order to interpret of cyclic orbital period changes for GR Vir, which has late-type components, possible magnetic activity cycles of the components have been also considered.

A compact E × B filter: A multi-collector cycloidal focusing mass spectrometer

Energy Technology Data Exchange (ETDEWEB)

Blase, Ryan C., E-mail: rblase@swri.edu; Miller, Greg; Brockwell, Tim; Waite, J. Hunter [Southwest Research Institute, 6220 Culebra Road, San Antonio, Texas 78238 (United States); Westlake, Joseph [The Johns Hopkins University Applied Physics Laboratory LLC, 11100 Johns Hopkins Road, Laurel, Maryland 20723 (United States); Ostrom, Nathaniel; Ostrom, Peggy H. [Department of Integrative Biology, Michigan State University, 288 Farm Lane RM 203, East Lansing, Michigan 48824 (United States)

2015-10-15

A compact E × B mass spectrometer is presented. The mass spectrometer presented is termed a “perfect focus” mass spectrometer as the resolution of the device is independent of both the initial direction and energy of the ions (spatial and energy independent). The mass spectrometer is small in size (∼10.7 in.{sup 3}) and weight (∼2 kg), making it an attractive candidate for portability when using small, permanent magnets. A multi-collector Faraday cup design allows for the detection of multiple ion beams in discrete collectors simultaneously; providing the opportunity for isotope ratio monitoring. The mass resolution of the device is around 400 through narrow collector slits and the sensitivity of the device follows expected theoretical calculations of the ion current produced in the electron impact ion source. Example mass spectra obtained from the cycloidal focusing mass spectrometer are presented as well as information on mass discrimination based on instrumental parameters and isotope ratio monitoring of certain ion signals in separate Faraday cups.

Electronic confinement in graphene quantum rings due to substrate-induced mass radial kink.

Science.gov (United States)

Xavier, L J P; da Costa, D R; Chaves, A; Pereira, J M; Farias, G A

2016-12-21

We investigate localized states of a quantum ring confinement in monolayer graphene defined by a circular mass-related potential, which can be induced e.g. by interaction with a substrate that breaks the sublattice symmetry, where a circular line defect provides a change in the sign of the induced mass term along the radial direction. Electronic properties are calculated analytically within the Dirac-Weyl approximation in the presence of an external magnetic field. Analytical results are also compared with those obtained by the tight-binding approach. Regardless of its sign, a mass term [Formula: see text] is expected to open a gap for low-energy electrons in Dirac cones in graphene. Both approaches confirm the existence of confined states with energies inside the gap, even when the width of the kink modelling the mass sign transition is infinitely thin. We observe that such energy levels are inversely proportional to the defect line ring radius and independent on the mass kink height. An external magnetic field is demonstrated to lift the valley degeneracy in this system and easily tune the valley index of the ground state in this system, which can be polarized on either K or [Formula: see text] valleys of the Brillouin zone, depending on the magnetic field intensity. Geometrical changes in the defect line shape are considered by assuming an elliptic line with different eccentricities. Our results suggest that any defect line that is closed in a loop, with any geometry, would produce the same qualitative results as the circular ones, as a manifestation of the topologically protected nature of the ring-like states investigated here.

Liquid and gas chromatography coupled to isotope ratio mass spectrometry for the determination of 13C-valine isotopic ratios in complex biological samples.

Science.gov (United States)

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

Magnetic moment of a bound electron

CERN Document Server

Czarnecki, Andrzej; Mondejar, Jorge; Piclum, Jan H

2010-01-01

Theoretical predictions underlying determinations of the fine structure constant alpha and the electron-to-proton mass ratio m_e/m_p are reviewed, with the emphasis on the bound electron magnetic anomaly g-2. The theory of the interaction of hydrogen-like ions with a magnetic field is discussed. The status of efforts aimed at the determination of O(alpha (Z alpha)^5) and O(alpha^2 (Z alpha)^5) corrections to the g factor is presented. The reevaluation of analogous corrections to the Lamb shift and the hyperfine splitting is summarized.

Obesity Index That Better Predict Metabolic Syndrome: Body Mass Index, Waist Circumference, Waist Hip Ratio, or Waist Height Ratio

Directory of Open Access Journals (Sweden)

Abdulbari Bener

2013-01-01

Full Text Available Aim. The aim was to compare body mass index (BMI, waist circumference (WC, waist hip ratio (WHR, and waist height ratio (WHtR to identify the best predictor of metabolic syndrome (MetS among Qatari adult population. Methods. A cross-sectional survey from April 2011 to December 2012. Data was collected from 1552 participants followed by blood sampling. MetS was defined according to Third Adult Treatment Panel (ATPIII and International Diabetes Federation (IDF. Receiver operating characteristics (ROC curve analysis was performed. Results. Among men, WC followed by WHR and WHtR yielded the highest area under the curve (AUC (0.78; 95% CI 0.74–0.82 and 0.75; 95% CI 0.71–0.79, resp.. Among women, WC followed by WHtR yielded the highest AUC (0.81; 95% CI 0.78–0.85 & 0.79; 95% CI 0.76–0.83, resp.. Among men, WC at a cut-off 99.5 cm resulted in the highest Youden index with sensitivity 81.6% and 63.9% specificity. Among women, WC at a cut-off 91 cm resulted in the highest Youden index with the corresponding sensitivity and specificity of 86.5% and 64.7%, respectively. BMI had the lowest sensitivity and specificity in both genders. Conclusion. WC at cut-off 99.5 cm in men and 91 cm in women was the best predictor of MetS in Qatar.

Two types of the effective mass divergence and the Grueneisen ratio in heavy-fermion metals

Energy Technology Data Exchange (ETDEWEB)

Amusia, M.Ya.; Msezane, A.Z.; Shaginyan, V.R

2004-01-12

The behavior of the specific heat c{sub p}, effective mass M*, and the thermal expansion coefficient {alpha} of a Fermi system located near the fermion condensation quantum phase transition (FCQPT) is considered. We observe the first type behavior if the system is close to FCQPT: the specific heat c{sub p}{proportional_to}{radical}T, M*{proportional_to}1/{radical}T, while the thermal expansion coefficient {alpha}{proportional_to}{radical}T. Thus, the Grueneisen ratio {gamma}(T)={alpha}/c{sub p} does not diverges. At the transition region, where the system passes over from the non-Fermi liquid to the Landau Fermi liquid, the ratio diverges as {gamma}(T){proportional_to}1/{radical}T. In the system becomes the Landau Fermi liquid, {gamma}(T,r){proportional_to}1/r, with r being a distance from the quantum critical point. Provided the system has undergone FCQPT, the second type takes place: the specific heat behaves as c{sub p}{proportional_to}{radical}T, M{sup *}{proportional_to}1/T, and {alpha}=a+bT with a,b being constants. Again, the Grueneisen ratio diverges as {gamma}(T){proportional_to}1/{radical}T.

On the vanishing electron-mass limit in plasma hydrodynamics in unbounded media

Czech Academy of Sciences Publication Activity Database

Donatelli, D.; Feireisl, Eduard; Novotný, A.

2012-01-01

Roč. 22, č. 6 (2012), s. 985-1012 ISSN 0938-8974 R&D Projects: GA ČR GA201/09/0917 Institutional research plan: CEZ:AV0Z10190503 Keywords : vanishing electron mass limit * plasma hydrodynamics * compressible fluid Subject RIV: BA - General Mathematics Impact factor: 1.566, year: 2012 http://link.springer.com/article/10.1007%2Fs00332-012-9134-5

Discontinuous Galerkin method for computing gravitational waveforms from extreme mass ratio binaries

International Nuclear Information System (INIS)

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

2009-01-01

Gravitational wave emission from extreme mass ratio binaries (EMRBs) should be detectable by the joint NASA-ESA LISA project, spurring interest in analytical and numerical methods for investigating EMRBs. We describe a discontinuous Galerkin (dG) method for solving the distributionally forced 1+1 wave equations which arise when modeling EMRBs via the perturbation theory of Schwarzschild black holes. Despite the presence of jump discontinuities in the relevant polar and axial gravitational 'master functions', our dG method achieves global spectral accuracy, provided that we know the instantaneous position, velocity and acceleration of the small particle. Here these variables are known, since we assume that the particle follows a timelike geodesic of the Schwarzschild geometry. We document the results of several numerical experiments testing our method, and in our concluding section discuss the possible inclusion of gravitational self-force effects.

On the interference of Kr during carbon isotope analysis of methane using continuous-flow combustion–isotope ratio mass spectrometry

NARCIS (Netherlands)

Schmitt, J.; Seth, B.; Bock, M; van der Veen, C.; Möller, L.; Sapart, C.J.; Prokopiou, M.; Sowers, T.; Röckmann, T.; Fischer, H

2013-01-01

Stable carbon isotope analysis of methane ( 13C of CH4) on atmospheric samples is one key method to constrain the current and past atmospheric CH4 budget. A frequently applied measurement technique is gas chromatography (GC) isotope ratio mass spectrometry (IRMS) coupled to a

Determination of uranium in urine - Measurement of isotope ratios and quantification by use of inductively coupled plasma mass spectrometry

NARCIS (Netherlands)

Krystek, Petra; Ritsema, R.

2002-01-01

For analysis of uranium in urine determination of the isotope ratio and quantification were investigated by high-resolution inductively coupled plasma mass spectrometry (HR ICP-MS). The instrument used (ThermoFinniganMAT ELEMENT2) is a single-collector MS and, therefore, a stable sample-introduction

The Interplay of In Situ Stress Ratio and Transverse Isotropy in the Rock Mass on Prestressed Concrete-Lined Pressure Tunnels

Science.gov (United States)

Simanjuntak, T. D. Y. F.; Marence, M.; Schleiss, A. J.; Mynett, A. E.

2016-11-01

This paper presents the mechanical and hydraulic behaviour of passively prestressed concrete-lined pressure tunnels embedded in elastic transversely isotropic rocks subjected to non-uniform in situ stresses. Two cases are distinguished based on whether the in situ vertical stress in the rock mass is higher, or lower than the in situ horizontal stress. A two-dimensional finite element model was used to study the influence of dip angle, α, and horizontal-to-vertical stress ratio, k, on the bearing capacity of prestressed concrete-lined pressure tunnels. The study reveals that the in situ stress ratio and the orientation of stratifications in the rock mass significantly affect the load sharing between the rock mass and the lining. The distribution of stresses and deformations as a result of tunnel construction processes exhibits a symmetrical pattern for tunnels embedded in a rock mass with either horizontal or vertical stratification planes, whereas it demonstrates an unsymmetrical pattern for tunnels embedded in a rock mass with inclined stratification planes. The results obtained for a specific value α with coefficient k are identical to that for α + 90° with coefficient 1/ k by rotating the tunnel axis by 90°. The maximum internal water pressure was determined by offsetting the prestress-induced hoop strains at the final lining intrados against the seepage-induced hoop strains. As well as assessing the internal water pressure, this approach is capable of identifying potential locations where longitudinal cracks may occur in the final lining.

An improved determination of the ratio of W and Z masses at the CERN anti pp collider

International Nuclear Information System (INIS)

Alitti, J.; Ambrosini, G.; Ansari, R.; Autiero, D.; Bareyre, P.; Bertram, I.A.; Blaylock, G.; Bonamy, P.; Borer, K.; Bourliaud, M.; Buskulic, D.; Carboni, G.; Cavalli, D.; Cavasinni, V.; Cenci, P.; Chollet, J.C.; Conta, C.; Costa, G.; Costantini, F.; Cozzi, L.; Cravero, A.; Curatolo, M.; Dell'Acqua, A.; DelPrete, T.; DeWolf, R.S.; DiLella, L.; Ducros, Y.; Egan, G.F.; Einsweiler, K.F.; Esposito, B.; Fayard, L.; Federspiel, A.; Ferrari, R.; Fraternali, M.; Froidevaux, D.; Fumagalli, G.; Gaillard, J.M.; Gianotti, F.; Gildemeister, O.; Goessling, C.; Goggi, V.G.; Gruenendahl, S.; Hara, K.; Hellman, S.; Hrivnac, J.; Hufnagel, H.; Hugentobler, E.; Hultqvist, K.; Iacopini, E.; Incandela, J.; Jakobs, K.; Jenni, P.; Kluge, E.E.; Kurz, N.; Lami, S.; Lariccia, P.; Lefebvre, M.; Linssen, L.; Livan, M.; Lubrano, P.; Magneville, C.; Mandelli, L.; Mapelli, L.; Mazzanti, M.; Meier, K.; Merkel, B.; Meyer, J.P.; Moniez, M.; Moning, R.; Morganti, M.; Mueller, L.; Munday, D.J.; Nessi, M.; Nessi-Tedaldi, F.; Onions, C.; Pal, T.; Parker, M.A.; Parrour, G.; Pastore, F.; Pennacchio, E.; Pentney, J.M.; Pepe, M.; Perini, L.; Petridou, C.; Petroff, P.; Plothow-Besch, H.; Polesello, G.; Poppleton, A.; Pretzl, K.; Primavera, M.; Punturo, M.; Repellin, J.P.; Rimoldi, A.; Sacchi, M.; Scampoli, P.; Schacher, J.; Schmidt, B.; Simak, V.; Singh, S.L.; Sondermann, V.; Spiwoks, R.; Stapnes, S.; Talamonti, C.; Tondini, F.; Tovey, S.N.; Tsesmelis, E.; Unal, G.; Valdata-Nappi, M.; Vercesi, V.; Weidberg, A.R.; Wells, P.S.; White, T.O.; Wood, D.R.; Wotton, S.A.; Zaccone, H.; Zylberstejn, A.

1992-01-01

The W and Z bosons masses, m W and m Z , are measured using samples of W→eν and Z→e + e - decays observed in anti pp collisions at √s=630 GeV. The ratio is found to be m W /m Z =0.8813±0.0036±0.0019. This gives a value sin 2 θ W =0.2234±0.0064±0.0033, and in combination with precise m Z measurements from LEP yields m W -80.35±0.33±0.17 GeV. This result is in good agreement with other experiments, and with the standard model for a top quark mass lighter than 250 GeV. (orig.)

CONSTRAINTS ON BLACK HOLE GROWTH, QUASAR LIFETIMES, AND EDDINGTON RATIO DISTRIBUTIONS FROM THE SDSS BROAD-LINE QUASAR BLACK HOLE MASS FUNCTION

International Nuclear Information System (INIS)

Kelly, Brandon C.; Hernquist, Lars; Siemiginowska, Aneta; Vestergaard, Marianne; Fan Xiaohui; Hopkins, Philip

2010-01-01

We present an estimate of the black hole mass function of broad-line quasars (BLQSOs) that self-consistently corrects for incompleteness and the statistical uncertainty in the mass estimates, based on a sample of 9886 quasars at 1 1 it is highly incomplete at M BH ∼ 9 M sun and L/L Edd ∼ BL > 150 ± 15 Myr for black holes at z = 1 with a mass of M BH = 10 9 M sun , and we constrain the maximum mass of a black hole in a BLQSO to be ∼3 x 10 10 M sun . Our estimated distribution of BLQSO Eddington ratios peaks at L/L Edd ∼ 0.05 and has a dispersion of ∼0.4 dex, implying that most BLQSOs are not radiating at or near the Eddington limit; however, the location of the peak is subject to considerable uncertainty. The steep increase in number density of BLQSOs toward lower Eddington ratios is expected if the BLQSO accretion rate monotonically decays with time. Furthermore, our estimated lifetime and Eddington ratio distributions imply that the majority of the most massive black holes spend a significant amount of time growing in an earlier obscured phase, a conclusion which is independent of the unknown obscured fraction. These results are consistent with models for self-regulated black hole growth, at least for massive systems at z > 1, where the BLQSO phase occurs at the end of a fueling event when black hole feedback unbinds the accreting gas, halting the accretion flow.

Study of High Mass Electron Pairs and High pT Phenomena

CERN Multimedia

2002-01-01

This experiment involves a modification of the apparatus used in R108, which extends the region of photon and electron detection to the entire azimuth, complementing the full azimuth charged particle detection already available. A five-fold increase in the acceptance for high mass e|+e|- pairs is thus achieved; the study of jets is also improved by extending the region of @g and @p|0 detection. An active converter consisting of lead glass and followed by a cathode strip read out MWPC is placed in front of each of the R108 lead glass arrays to improve @g/@p|0 discrimination. The modified apparatus is shown in the Figure. The specific physics aims of the experiment are: \\item 1) Search for high mass states decaying into e|+e|-. In a 3000-hour run the sensitivity is 2\\% of the @U cross-section for 10 detected events. \\item 2) Study of e|+e|- pair production above the @U mass. As well as the cross-section, the transverse momentum and rapidity distributions will be measured, providing a crucial test of QCD as appl...

Can body mass index, waist circumference, waist-hip ratio and waist-height ratio predict the presence of multiple metabolic risk factors in Chinese subjects?

Directory of Open Access Journals (Sweden)

Lu Liping

2011-01-01

Full Text Available Abstract Background Obesity is associated with metabolic risk factors. Body mass index (BMI, waist circumference, waist-hip ratio (WHR and waist-height ratio (WHtR are used to predict the risk of obesity related diseases. However, it has not been examined whether these four indicators can detect the clustering of metabolic risk factors in Chinese subjects. Methods There are 772 Chinese subjects in the present study. Metabolic risk factors including high blood pressure, dyslipidemia, and glucose intolerance were identified according to the criteria from WHO. All statistical analyses were performed separately according to sex by using the SPSS 12.0. Results BMI, waist circumference and WHtR values were all significantly associated with blood pressure, glucose, triglyceride and also with the number of metabolic risk factors in both male and female subjects (all of P Conclusion The BMI, waist circumference and WHtR values can similarly predict the presence of multiple metabolic risk factors in Chinese subjects.

Solitary waves in dusty plasmas with weak relativistic effects in electrons and ions

Energy Technology Data Exchange (ETDEWEB)

Kalita, B. C., E-mail: bckalita123@gmail.com [Gauhati University, Department of Mathematics (India); Choudhury, M., E-mail: choudhurymamani@gmail.com [Handique Girls’ College, Department of Mathematics (India)

2016-10-15

Two distinct classes of dust ion acoustic (DIA) solitary waves based on relativistic ions and electrons, dust charge Z{sub d} and ion-to-dust mass ratio Q’ = m{sub i}/m{sub d} are established in this model of multicomponent plasmas. At the increase of mass ratio Q’ due to increase of relativistic ion mass and accumulation of more negative dust charges into the plasma causing decrease of dust mass, relativistic DIA solitons of negative potentials are abundantly observed. Of course, relativistic compressive DIA solitons are also found to exist simultaneously. Further, the decrease of temperature inherent in the speed of light c causes the nonlinear term to be more active that increases the amplitude of the rarefactive solitons and dampens the growth of compressive solitons for relatively low and high mass ratio Q’, respectively. The impact of higher initial streaming of the massive ions is observed to identify the point of maximum dust density N{sub d} to yield rarefactive relativistic solitons of maximum amplitude.

Effects of positron density and temperature on large amplitude ion-acoustic waves in an electron-positron-ion plasma

International Nuclear Information System (INIS)

Nejoh, Y.N.

1997-01-01

The nonlinear wave structures of large amplitude ion-acoustic waves are studied in a plasma with positrons. We have presented the region of existence of the ion-acoustic waves by analysing the structure of the pseudopotential. The region of existence sensitively depends on the positron to electron density ratio, the ion to electron mass ratio and the positron to electron temperature ratio. It is shown that the maximum Mach number increases as the positron temperature increases and the region of existence of the ion-acoustic waves spreads as the positron temperature increases. 12 refs., 6 figs

Investigation of Electron Beam Induced Mass Loss of Embedding Media in the Low Voltage STEM

Czech Academy of Sciences Publication Activity Database

Novotná, V.; Hrubanová, Kamila; Nebesářová, J.; Krzyžánek, Vladislav

2014-01-01

Roč. 20, S3 (2014), s. 1270-1271 ISSN 1431-9276 R&D Projects: GA MŠk EE.2.3.20.0103; GA MŠk(CZ) LO1212; GA ČR(CZ) GA14-20012S; GA TA ČR TE01020118 Institutional support: RVO:68081731 Keywords : mass loss * mass -thickness measurement * low voltage STEM Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.877, year: 2014

The calibration of the intramolecular nitrogen isotope distribution in nitrous oxide measured by isotope ratio mass spectrometry.

Science.gov (United States)

Westley, Marian B; Popp, Brian N; Rust, Terri M

2007-01-01

Two alternative approaches for the calibration of the intramolecular nitrogen isotope distribution in nitrous oxide using isotope ratio mass spectrometry have yielded a difference in the 15N site preference (defined as the difference between the delta15N of the central and end position nitrogen in NNO) of tropospheric N2O of almost 30 per thousand. One approach is based on adding small amounts of labeled 15N2O to the N2O reference gas and tracking the subsequent changes in m/z 30, 31, 44, 45 and 46, and this yields a 15N site preference of 46.3 +/- 1.4 per thousand for tropospheric N2O. The other involves the synthesis of N2O by thermal decomposition of isotopically characterized ammonium nitrate and yields a 15N site preference of 18.7 +/- 2.2 per thousand for tropospheric N2O. Both approaches neglect to fully account for isotope effects associated with the formation of NO+ fragment ions from the different isotopic species of N2O in the ion source of a mass spectrometer. These effects vary with conditions in the ion source and make it impossible to reproduce a calibration based on the addition of isotopically enriched N2O on mass spectrometers with different ion source configurations. These effects have a much smaller impact on the comparison of a laboratory reference gas with N2O synthesized from isotopically characterized ammonium nitrate. This second approach was successfully replicated and leads us to advocate the acceptance of the site preference value 18.7 +/- 2.2 per thousand for tropospheric N2O as the provisional community standard until further independent calibrations are developed and validated. We present a technique for evaluating the isotope effects associated with fragment ion formation and revised equations for converting ion signal ratios into isotopomer ratios. Copyright 2007 John Wiley & Sons, Ltd.

Measurement of Muscle Protein Fractional Synthetic Rate by Capillary Gas Chromatography/Combustion Isotope Ratio Mass Spectrometry

OpenAIRE

Yarasheski, Kevin E.; Smith, Kenneth; Rennie, Michael J.; Bier, Dennis M.

1992-01-01

The measurement of skeletal muscle protein fractional synthetic rate using an infusion of (1-13C)leucine and measuring the isotopic abundance of the tracer in skeletal muscle protein by preparative gas chromatography (GC)/ninhydrin isotope ratio mass spectrometry (IRMS) is laborious and subject to errors owing to contamination by 12C. The purpose of this study was to compare muscle (13C)leucine enrichment measured with the conventional preparative GC/ninhydrin IRMS approach to a new, continuo...

Online Stable Isotope Analysis of Dissolved Organic Carbon Size Classes Using Size Exclusion Chromatography Coupled to an Isotope Ratio Mass Spectrometer

Digital Repository Service at National Institute of Oceanography (India)

Malik, A.; Scheibe, A.; LokaBharathi, P.A.; Gleixner, G.

size classes by coupling high-performance liquid chromatography (HPLC) - size exclusion chromatography (SEC) to online isotope ratio mass spectrometry (IRMS). This represents a significant methodological contribution to DOC research. The interface...

Improved limit on the electron anti neutrino rest mass from tritium β decay

International Nuclear Information System (INIS)

Weinheimer, C.; Przyrembel, M.; Backe, H.; Barth, H.; Bonn, J.; Degen, B.; Edling, T.; Fischer, H.; Fleischmann, L.; Grooss, J.U.; Haid, R.; Hermanni, A.; Kube, G.; Loeken, T.; Molz, A.; Osipowicz, A.; Otten, E.W.; Picard, A.; Schrader, M.; Steininger, M.

1993-01-01

This paper presents the results of a re-measurement of the endpoint region of the beta-spectrum of tritium by an electrostatic spectrometer with magnetic guiding field. It enables the search for a rest mass of the electron anti neutrino with improved precision. The result is: m ν 2 =(-39±34 stat ±15 syst ) (eV/c 2 ) 2 , from which an upper limit of: m ν 2 may be derived. The experiment yields the atomic mass difference: m(T)-m( 3 He)=(18591±3) eV/c 2 . (TEC). 31 refs., 4 figs., 3 tabs

Evaluation of gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) for the quality assessment of citrus liqueurs.

Science.gov (United States)

Schipilliti, Luisa; Bonaccorsi, Ivana; Cotroneo, Antonella; Dugo, Paola; Mondello, Luigi

2013-02-27

Citrus liqueurs are alcoholic beverages obtained by maceration. The European Parliament protects these alcoholic beverages, forbidding the addition of nature-identical flavoring substances. However, for economical and technological reasons, producers often add natural and/or synthetic flavors to the alcoholic syrup, obtaining artificial spirit drinks. The aim of this study is to investigate the authenticity of Italian liqueurs, of lemon, bergamot, and mandarin (locally known as "limoncello", "bargamino", and "mandarinetto"), comparing the carbon isotope ratios with values determined in genuine cold-pressed peel oils. Authenticity assessment was performed using headspace-solid phase microextraction coupled to gas chromatography-combustion-isotope ratio mass spectrometry. Additional analyses were performed by direct enantioselective gas chromatography to determine the enantiomeric distribution of selected chiral volatiles and by gas chromatography-mass spectrometry for the qualitative analyses of the samples. The method allowed confirmation of genuineness. Enantioselective gas chromatography analyses confirmed the results, demonstrating the reliability of the method.

Simultaneous Detection of Androgen and Estrogen Abuse in Breeding Animals by Gas Chromatography-Mass Spectrometry/Combustion/Isotope Ratio Mass Spectrometry (GC-MS/C/IRMS) Evaluated against Alternative Methods.

Science.gov (United States)

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

2015-09-02

The administration of synthetic homologues of naturally occurring steroids can be demonstrated by measuring (13)C/(12)C isotopic ratios of their urinary metabolites. Gas chromatography-mass spectrometry/combustion/isotope ratio mass spectrometry (GC-MS/C/IRMS) was used in this study to appraise in a global approach isotopic deviations of two 17β-testosterone metabolites (17α-testosterone and etiocholanolone) and one 17β-estradiol metabolite (17α-estradiol) together with those of 5-androstene-3β,17α-diol as endogenous reference compound (ERC). Intermediate precisions of 0.35‰, 1.05‰, 0.35‰, and 0.21‰, respectively, were observed (n = 8). To assess the performance of the analytical method, a bull and a heifer were treated with 17β-testosterone propionate and 17β-estradiol-3-benzoate. The sensitivity of the method permitted the demonstration of 17β-estradiol treatment up to 24 days. For 17β-testosterone treatment, the detection windows were 3 days and 24 days for the bull and the heifer, respectively. The capability of GC-MS/C/IRMS to demonstrate natural steroid abuse for urinary steroids was eventually compared to those of mass spectrometry (LC-MS/MS) when measuring intact steroid esters in blood and hair.

Chlorine isotope effects from isotope ratio mass spectrometry suggest intramolecular C-Cl bond competition in trichloroethene (TCE) reductive dehalogenation.

Science.gov (United States)

Cretnik, Stefan; Bernstein, Anat; Shouakar-Stash, Orfan; Löffler, Frank; Elsner, Martin

2014-05-20

Chlorinated ethenes are prevalent groundwater contaminants. To better constrain (bio)chemical reaction mechanisms of reductive dechlorination, the position-specificity of reductive trichloroethene (TCE) dehalogenation was investigated. Selective biotransformation reactions (i) of tetrachloroethene (PCE) to TCE in cultures of Desulfitobacterium sp. strain Viet1; and (ii) of TCE to cis-1,2-dichloroethene (cis-DCE) in cultures of Geobacter lovleyi strain SZ were investigated. Compound-average carbon isotope effects were -19.0‰ ± 0.9‰ (PCE) and -12.2‰ ± 1.0‰ (TCE) (95% confidence intervals). Using instrumental advances in chlorine isotope analysis by continuous flow isotope ratio mass spectrometry, compound-average chorine isotope effects were measured for PCE (-5.0‰ ± 0.1‰) and TCE (-3.6‰ ± 0.2‰). In addition, position-specific kinetic chlorine isotope effects were determined from fits of reactant and product isotope ratios. In PCE biodegradation, primary chlorine isotope effects were substantially larger (by -16.3‰ ± 1.4‰ (standard error)) than secondary. In TCE biodegradation, in contrast, the product cis-DCE reflected an average isotope effect of -2.4‰ ± 0.3‰ and the product chloride an isotope effect of -6.5‰ ± 2.5‰, in the original positions of TCE from which the products were formed (95% confidence intervals). A greater difference would be expected for a position-specific reaction (chloride would exclusively reflect a primary isotope effect). These results therefore suggest that both vicinal chlorine substituents of TCE were reactive (intramolecular competition). This finding puts new constraints on mechanistic scenarios and favours either nucleophilic addition by Co(I) or single electron transfer as reductive dehalogenation mechanisms.

Electron multiplier for the measurement of an ion current on a mass spectrometer; Multiplicateur d'electrons pour la mesure de courant d'ions sur un spectrometre de masse

Energy Technology Data Exchange (ETDEWEB)

Lohez, P; Nief, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1957-07-01

The apparatus described is designed to measure weak ion currents received at the collector of a mass spectrometer. The report describes successively the study of electron paths in the multiplier by the method of analogy, using rubber membranes, and the practical details of construction of the apparatus. The variation with surface treatment of the secondary emission coefficient of the alloy CuBe containing 2 per cent Be, which makes up the dynodes, and the influence of the voltage on the gain per stage, are discussed. Results of tests regarding: the influence of the ion mass on the gain, the background of the instrument and the energy distribution of the impulses coming out on a high gain multiplier (q.q. 10{sup 7}) are given. Finally the performances of the multiplier are reported. 1- For a low gain (10{sup 4}), precision and reproducibility comparable to the electrometer valve, sensitivity 100 times greater, currents capable of detection 10{sup -17} Ampere. 2- For a high gain (10{sup 7}) and measurement by impulse counting, currents capable of detection 10{sup -19} Ampere. Mounting difficult to use on a mass spectrometer. (author) [French] L'appareil decrit est destine a la mesure des faibles courants d'ions re s au collecteur d'un spectrometre de masse. Le rapport decrit successivement l'etude des trajectoires des electrons dans le multiplicateur, par la methode analogique de la menbrane en caoutchouc, et la realisation pratique de l'appareil. La variation du coefficient d'emission secondaire de l'alliage CuBe a 2 pour cent de Be, constituant les dynodes suivant le traitement des surfaces, et l'influence de la tension sur le gain par etage sont discutees. Des resultats d'essais concernant: l'influence de la masse des ions sur le gain, le bruit de fond de l'appareil et la repartition en energie des impulsions de sortie sur un multiplicateur a gain eleve (q.q. 10{sup 7}) sont donnes. Enfin, sont rapportees les performances du multiplicateur. 1- pour un gain faible

Limb/trunk lean mass ratio as a risk factor for mortality in peritoneal dialysis patients.

Science.gov (United States)

Kang, Seok Hui; Park, Jong Won; Yoon, Kyung Woo; Do, Jun Young

2013-07-01

This study was performed to determine the clinical relevance of limb/trunk lean mass ratio (LTLM) in continuous ambulatory peritoneal dialysis (CAPD) patients. This retrospective cohort study included 534 CAPD patients. Body compositions were measured using a dual-energy X-ray absorptiometry apparatus. In males, the sensitivity and specificity for the diagnosis of sarcopenia were 70.3% and 85.9%, respectively. Respective values in females were 62.3% and 83.8%. The initial low LTLM tertile was associated with mortality in male CAPD patients and in female CAPD patients. Among patients who maintained CAPD for a year, the maintenance of low LTLM tertile was associated with mortality. LTLM is associated with other lean mass indices, nutritional status, and mortality in CAPD patients. Therefore, LTLM is a novel marker that is useful for the prediction of the nutritional status and mortality in patients with CAPD. Copyright © 2013 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Mass measurements of neutron rich isotopes in the Fe region and electron capture processes in neutron star crusts

International Nuclear Information System (INIS)

Estrade, Alfredo; Matos, M.; Schatz, Hendrik; Amthor, A.M.; Beard, Mary; Brown, Edward; Bazin, D.; Becerril, A.; Elliot, T.; Gade, A.; Galaviz, D.; Gupta, Sanjib; Hix, William Raphael; Lau, Rita; Moeller, Peter; Pereira, J.; Portillo, M.; Rogers, A.M.; Shapira, Dan; Smith, E.; Stolz, A.; Wallace, M.; Wiescher, Michael

2011-01-01

Experimental knowledge of nuclear masses of exotic nuclei is important for understanding nuclear structure far from the valley of stability, and as a direct input into astrophysical models. Electron capture processes in the crust of accreting neutron stars have been proposed as a heat source that can affect the thermal structure of the star. Nuclear masses of very neutron-rich nuclides are necessary inputs to model the electron capture process. The time-of-flight (TOF) mass measurement technique allows measurements on very short-lived nuclei. It has been effectively applied using the fast fragment beams produced at the National Superconducting Cyclotron Lab (NSCL) to reach masses very far from stability. Measurements were performed for neutron-rich isotopes in the region of the N=32 and N=40 subshells, which coincides with the mass range of carbon superburst ashes. We discuss reaction network calculations performed to investigate the impact of our new measurements and to compare the effect of using different global mass models in the calculations. It is observed that the process is sensitive to the differences in the odd-even mass staggering predicted by the mass models, and our new result for 66Mn has a significant impact on the distribution of heat sources in the crust.

First measurement of the ratio of central-electron to forward-electron W partial cross sections in pp[over] collisions at (square root)s =1.96 TeV.

Science.gov (United States)

Abulencia, A; Adelman, J; Affolder, T; Akimoto, T; Albrow, M G; Amerio, S; Amidei, D; Anastassov, A; Anikeev, K; Annovi, A; Antos, J; Aoki, M; Apollinari, G; Arisawa, T; Artikov, A; Ashmanskas, W; Attal, A; Aurisano, A; Azfar, F; Azzi-Bacchetta, P; Azzurri, P; Bacchetta, N; Badgett, W; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Baroiant, S; Bartsch, V; Bauer, G; Beauchemin, P-H; Bedeschi, F; Behari, S; Bellettini, G; Bellinger, J; Belloni, A; Benjamin, D; Beretvas, A; Beringer, J; Berry, T; Bhatti, A; Binkley, M; Bisello, D; Bizjak, I; Blair, R E; Blocker, C; Blumenfeld, B; Bocci, A; Bodek, A; Boisvert, V; Bolla, G; Bolshov, A; Bortoletto, D; Boudreau, J; Boveia, A; Brau, B; Brigliadori, L; Bromberg, C; Brubaker, E; Budagov, J; Budd, H S; Budd, S; Burkett, K; Busetto, G; Bussey, P; Buzatu, A; Byrum, K L; Cabrera, S; Campanelli, M; Campbell, M; Canelli, F; Canepa, A; Carillo, S; Carlsmith, D; Carosi, R; Carron, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chang, S H; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, I; Cho, K; Chokheli, D; Chou, J P; Choudalakis, G; Chuang, S H; Chung, K; Chung, W H; Chung, Y S; Cilijak, M; Ciobanu, C I; Ciocci, M A; Clark, A; Clark, D; Coca, M; Compostella, G; Convery, M E; Conway, J; Cooper, B; Copic, K; Cordelli, M; Cortiana, G; Crescioli, F; Almenar, C Cuenca; Cuevas, J; Culbertson, R; Cully, J C; DaRonco, S; Datta, M; D'Auria, S; Davies, T; Dagenhart, D; de Barbaro, P; De Cecco, S; Deisher, A; De Lentdecker, G; De Lorenzo, G; Dell'Orso, M; Delli Paoli, F; Demortier, L; Deng, J; Deninno, M; De Pedis, D; Derwent, P F; Giovanni, G P Di; Dionisi, C; Di Ruzza, B; Dittmann, J R; D'Onofrio, M; Dörr, C; Donati, S; Dong, P; Donini, J; Dorigo, T; Dube, S; Efron, J; Erbacher, R; Errede, D; Errede, S; Eusebi, R; Fang, H C; Farrington, S; Fedorko, I; Fedorko, W T; Feild, R G; Feindt, M; Fernandez, J P; Field, R; Flanagan, G; Forrest, R; Forrester, S; Franklin, M; Freeman, J C; Furic, I; Gallinaro, M; Galyardt, J; Garcia, J E; Garberson, F; Garfinkel, A F; Gay, C; Gerberich, H; Gerdes, D; Giagu, S; Giannetti, P; Gibson, K; Gimmell, J L; Ginsburg, C; Giokaris, N; Giordani, M; Giromini, P; Giunta, M; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldschmidt, N; Goldstein, J; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gresele, A; Grinstein, S; Grosso-Pilcher, C; Grundler, U; Guimaraes da Costa, J; Gunay-Unalan, Z; Haber, C; Hahn, K; Hahn, S R; Halkiadakis, E; Hamilton, A; Han, B-Y; Han, J Y; Handler, R; Happacher, F; Hara, K; Hare, D; Hare, M; Harper, S; Harr, R F; Harris, R M; Hartz, M; Hatakeyama, K; Hauser, J; Hays, C; Heck, M; Heijboer, A; Heinemann, B; Heinrich, J; Henderson, C; Herndon, M; Heuser, J; Hidas, D; Hill, C S; Hirschbuehl, D; Hocker, A; Holloway, A; Hou, S; Houlden, M; Hsu, S-C; Huffman, B T; Hughes, R E; Husemann, U; Huston, J; Incandela, J; Introzzi, G; Iori, M; Ivanov, A; Iyutin, B; James, E; Jang, D; Jayatilaka, B; Jeans, D; Jeon, E J; Jindariani, S; Johnson, W; Jones, M; Joo, K K; Jun, S Y; Jung, J E; Junk, T R; Kamon, T; Karchin, P E; Kato, Y; Kemp, Y; Kephart, R; Kerzel, U; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kim, Y K; Kimura, N; Kirsch, L; Klimenko, S; Klute, M; Knuteson, B; Ko, B R; Kondo, K; Kong, D J; Konigsberg, J; Korytov, A; Kotwal, A V; Kraan, A C; Kraus, J; Kreps, M; Kroll, J; Krumnack, N; Kruse, M; Krutelyov, V; Kubo, T; Kuhlmann, S E; Kuhr, T; Kulkarni, N P; Kusakabe, Y; Kwang, S; Laasanen, A T; Lai, S; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; Lazzizzera, I; LeCompte, T; Lee, J; Lee, J; Lee, Y J; Lee, S W; Lefèvre, R; Leonardo, N; Leone, S; Levy, S; Lewis, J D; Lin, C; Lin, C S; Lindgren, M; Lipeles, E; Lister, A; Litvintsev, D O; Liu, T; Lockyer, N S; Loginov, A; Loreti, M; Lu, R-S; Lucchesi, D; Lujan, P; Lukens, P; Lungu, G; Lyons, L; Lys, J; Lysak, R; Lytken, E; Mack, P; MacQueen, D; Madrak, R; Maeshima, K; Makhoul, K; Maki, T; Maksimovic, P; Malde, S; Malik, S; Manca, G; Manousakis, A; Margaroli, F; Marginean, R; Marino, C; Marino, C P; Martin, A; Martin, M; Martin, V; Martínez, M; Martínez-Ballarín, R; Maruyama, T; Mastrandrea, P; Masubuchi, T; Matsunaga, H; Mattson, M E; Mazini, R; Mazzanti, P; McFarland, K S; McIntyre, P; McNulty, R; Mehta, A; Mehtala, P; Menzemer, S; Menzione, A; Merkel, P; Mesropian, C; Messina, A; Miao, T; Miladinovic, N; Miles, J; Miller, R; Mills, C; Milnik, M; Mitra, A; Mitselmakher, G; Miyamoto, A; Moed, S; Moggi, N; Mohr, B; Moon, C S; Moore, R; Morello, M; Fernandez, P Movilla; Mülmenstädt, J; Mukherjee, A; Muller, Th; Mumford, R; Murat, P; Mussini, M; Nachtman, J; Nagano, A; Naganoma, J; Nakamura, K; Nakano, I; Napier, A; Necula, V; Neu, C; Neubauer, M S; Nielsen, J; Nodulman, L; Norniella, O; Nurse, E; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Oldeman, R; Orava, R; Osterberg, K; Pagliarone, C; Palencia, E; Papadimitriou, V; Papaikonomou, A; Paramonov, A A; Parks, B; Pashapour, S; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Pellett, D E; Penzo, A; Phillips, T J; Piacentino, G; Piedra, J; Pinera, L; Pitts, K; Plager, C; Pondrom, L; Portell, X; Poukhov, O; Pounder, N; Prakoshyn, F; Pronko, A; Proudfoot, J; Ptohos, F; Punzi, G; Pursley, J; Rademacker, J; Rahaman, A; Ramakrishnan, V; Ranjan, N; Redondo, I; Reisert, B; Rekovic, V; Renton, P; Rescigno, M; Richter, S; Rimondi, F; Ristori, L; Robson, A; Rodrigo, T; Rogers, E; Rolli, S; Roser, R; Rossi, M; Rossin, R; Roy, P; Ruiz, A; Russ, J; Rusu, V; Saarikko, H; Safonov, A; Sakumoto, W K; Salamanna, G; Saltó, O; Santi, L; Sarkar, S; Sartori, L; Sato, K; Savard, P; Savoy-Navarro, A; Scheidle, T; Schlabach, P; Schmidt, E E; Schmidt, M P; Schmitt, M; Schwarz, T; Scodellaro, L; Scott, A L; Scribano, A; Scuri, F; Sedov, A; Seidel, S; Seiya, Y; Semenov, A; Sexton-Kennedy, L; Sfyrla, A; Shalhout, S Z; Shapiro, M D; Shears, T; Shepard, P F; Sherman, D; Shimojima, M; Shochet, M; Shon, Y; Shreyber, I; Sidoti, A; Sinervo, P; Sisakyan, A; Slaughter, A J; Slaunwhite, J; Sliwa, K; Smith, J R; Snider, F D; Snihur, R; Soderberg, M; Soha, A; Somalwar, S; Sorin, V; Spalding, J; Spinella, F; Spreitzer, T; Squillacioti, P; Stanitzki, M; Staveris-Polykalas, A; Denis, R St; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Stuart, D; Suh, J S; Sukhanov, A; Sun, H; Suslov, I; Suzuki, T; Taffard, A; Takashima, R; Takeuchi, Y; Tanaka, R; Tecchio, M; Teng, P K; Terashi, K; Thom, J; Thompson, A S; Thomson, E; Tipton, P; Tiwari, V; Tkaczyk, S; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Tourneur, S; Trischuk, W; Tsuno, S; Tu, Y; Turini, N; Ukegawa, F; Uozumi, S; Vallecorsa, S; van Remortel, N; Varganov, A; Vataga, E; Vazquez, F; Velev, G; Vellidis, C; Veramendi, G; Veszpremi, V; Vidal, M; Vidal, R; Vila, I; Vilar, R; Vine, T; Vollrath, I; Volobouev, I; Volpi, G; Würthwein, F; Wagner, P; Wagner, R G; Wagner, R L; Wagner, J; Wagner, W; Wallny, R; Wang, S M; Warburton, A; Waters, D; Weinberger, M; Wester, W C; Whitehouse, B; Whiteson, D; Wicklund, A B; Wicklund, E; Williams, G; Williams, H H; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, C; Wright, T; Wu, X; Wynne, S M; Yagil, A; Yamamoto, K; Yamaoka, J; Yamashita, T; Yang, C; Yang, U K; Yang, Y C; Yao, W M; Yeh, G P; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Yu, S S; Yun, J C; Zanello, L; Zanetti, A; Zaw, I; Zhang, X; Zhou, J; Zucchelli, S

2007-06-22

We present a measurement of sigma(pp[over] --> W) x B(W --> e nu) at (square root)s = 1.96 TeV, using electrons identified in the forward region (1.2 < |eta| < 2.8) of the CDF II detector, in 223 pb(-1) of data. We measure sigma x B = 2796 +/- 13(stat)(-90)(+95)(syst) +/- 162(lum) pb. Combining this result with a previous CDF measurement obtained using electrons in the central region (|eta| approximately < 1), we present the first measurement of the ratio of central-electron to forward-electron W partial cross sections R(exp) = 0.925 +/- 0.006(stat) +/- 0.032(syst), consistent with theoretical predictions using Coordinated Theoretical-Experimental Project on QCD (CTEQ) and Martin-Roberts-Stirling-Thorne (MRST) parton distribution functions.

Rapid quantification of free cholesterol in tears using direct insertion/electron ionization-mass spectrometry.

Science.gov (United States)

Wei, Xiaojia Eric; Korth, John; Brown, Simon H J; Mitchell, Todd W; Truscott, Roger J W; Blanksby, Stephen J; Willcox, Mark D P; Zhao, Zhenjun

2013-12-09

To establish a simple and rapid analytical method, based on direct insertion/electron ionization-mass spectrometry (DI/EI-MS), for measuring free cholesterol in tears from humans and rabbits. A stable-isotope dilution protocol employing DI/EI-MS in selected ion monitoring mode was developed and validated. It was used to quantify the free cholesterol content in human and rabbit tear extracts. Tears were collected from adult humans (n = 15) and rabbits (n = 10) and lipids extracted. Screening, full-scan (m/z 40-600) DI/EI-MS analysis of crude tear extracts showed that diagnostic ions located in the mass range m/z 350 to 400 were those derived from free cholesterol, with no contribution from cholesterol esters. DI/EI-MS data acquired using selected ion monitoring (SIM) were analyzed for the abundance ratios of diagnostic ions with their stable isotope-labeled analogues arising from the D6-cholesterol internal standard. Standard curves of good linearity were produced and an on-probe limit of detection of 3 ng (at 3:1 signal to noise) and limit of quantification of 8 ng (at 10:1 signal to noise). The concentration of free cholesterol in human tears was 15 ± 6 μg/g, which was higher than in rabbit tears (10 ± 5 μg/g). A stable-isotope dilution DI/EI-SIM method for free cholesterol quantification without prior chromatographic separation was established. Using this method demonstrated that humans have higher free cholesterol levels in their tears than rabbits. This is in agreement with previous reports. This paper provides a rapid and reliable method to measure free cholesterol in small-volume clinical samples.

Systematic study of low-mass electron pair production in p-Be and p-Au collisions at 450 GeV/c

NARCIS (Netherlands)

Agakichiev, G; Appenheimer, M; Averbeck, R; Ballester, F; Baur, R; Brenschede, A; Diaz, J; Drees, A; Faschingbauer, U; Ferrero, JL; Fraenkel, Z; Franke, M; Fuchs, C; Gatti, E; Glassel, P; Gunzel, T; de los Heros, CP; Hess, F; Holzmann, R; Iourevitch, [No Value; Irmscher, D; Jacob, C; Kuhn, W; Lenkeit, B; Löhner, H.; Marin, A; Marques, FM; Martinez, G; Metag, [No Value; Notheisen, M; Novotny, R; Olsen, LH; Ostendorf, R; Panebrattsev, Y; Pfeiffer, A; Ravinovich, [No Value; Rehak, P; Sampietro, M; Schon, A; Schukraft, J; Schutz, Y; Shimansky, S; Shor, A; Simon, RS; Specht, HJ; Steiner, [No Value; Tapprogge, S; Tel-Zur, G; Tserruya, [No Value; Ullrich, T; Wilschut, H.; Wurm, JP

In a joint effort the CERES/NA45 and TAPS collaborations have measured low-mass electron pairs in p-Be and p-Au collisions at 450 GeV/c at the CERN SPS. In the range covered up to approximate to 1.5 GeV/c(2) the mass spectra from p-Be and p-Au collisions are well explained by electron pairs from

The potential of Isotope Ratio Mass Spectrometry (IRMS) and gas chromatography-IRMS analysis of triacetone triperoxide in forensic explosives investigations

NARCIS (Netherlands)

Bezemer, K.D.B.; Koeberg, M.; Heijden, A.E.D.M. van der; Driel, C.A. va; Blaga, C.; Bruinsma, J.; Asten, A.C. van

2016-01-01

Studying links between triacetone triperoxide (TATP) samples from crime scenes and suspects can assist in criminal investigations. Isotope ratio mass spectrometry (IRMS) and gas chromatography (GC)-IRMS were used to measure the isotopic compositions of TATP and its precursors acetone and hydrogen

Active renin mass concentration to determine aldosterone-to-renin ratio in screening for primary aldosteronism

Directory of Open Access Journals (Sweden)

Corbin F

2011-07-01

Full Text Available François Corbin1, Pierre Douville2, Marcel Lebel3 1Division of Biochemistry, l'Université de Sherbrooke, Sherbrooke, Quebec, Canada; 2Division of Biochemistry; 3Division of Nephrology, L'Hôtel-Dieu de Québec Hospital and l'Université Laval, Quebec, CanadaBackground: Active renin mass concentration (ARC is independent of the endogenous level of angiotensinogen, and less variable and more reproducible than plasma renin activity. Reference values for the aldosterone-to-renin ratio (ARR using ARC are still undefined. The objective of the present study was to determine the threshold of ARR using ARC measurement to screen for primary aldosteronism.Methods: A total of 211 subjects were included in the study, comprising 78 healthy normotensive controls, 95 patients with essential hypertension, and 38 patients with confirmed primary aldosteronism (20 with surgery-confirmed aldosterone-producing adenoma and 18 with idiopathic adrenal hyperplasia. Blood samples were drawn from ambulatory patients and volunteers in the mid-morning without specific dietary restriction for measuring plasma aldosterone concentration, ARC, and serum potassium.Results: Most normotensive controls and essential hypertension patients had ARR results below 100 pmol/ng, a value which corresponded to 3.3 times the median of these two groups.Conclusion: Patients with ARR values above this level should be considered for further investigation (confirmatory tests or for repeat testing should ARR values be borderline. This study indicates that ARC can be used reliably in determining ARR for primary aldosteronism screening.Keywords: primary aldosteronism, active renin mass concentration, aldosterone-to-renin ratio

Neutrinos in the Electron

International Nuclear Information System (INIS)

Koschmieder, E. L.

2007-01-01

I will show that one half of the rest mass of the electron consists of electron neutrinos and that the other half of the rest mass of the electron consists of the mass in the energy of electric oscillations. With this composition we can explain the rest mass of the electron, its charge, its spin and its magnetic moment We have also determined the rest masses of the muon neutrino and the electron neutrino

Spatially tracking 13C labeled substrate (bicarbonate) accumulation in microbial communities using laser ablation isotope ratio mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

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.

Accurate and precise 40Ar/39Ar dating by high-resolution, multi-collection, mass spectrometry

DEFF Research Database (Denmark)

Storey, Michael; Rivera, Tiffany; Flude, Stephanie

New generation, high resolution, multi-collector noble gas mass spectrometers equipped with ion-counting electron multipliers provide opportunities for improved accuracy and precision in 40Ar/39Ar dating. Here we report analytical protocols and age cross-calibration studies using a NU-Instruments......New generation, high resolution, multi-collector noble gas mass spectrometers equipped with ion-counting electron multipliers provide opportunities for improved accuracy and precision in 40Ar/39Ar dating. Here we report analytical protocols and age cross-calibration studies using a NU......-Instruments multi-collector Noblesse noble gas mass spectrometer configured with a faraday detector and three ion-counting electron multipliers. The instrument has the capability to measure several noble gas isotopes simultaneously and to change measurement configurations instantaneously by the use of QUAD lenses...... (zoom optics). The Noblesse offer several advantages over previous generation noble gas mass spectrometers and is particularly suited for single crystal 40Ar/39Ar dating because of: (i) improved source sensitivity (ii) ion-counting electron multipliers, which have much lower signal to noise ratios than...

Polar and non-polar organic aerosols from large-scale agricultural-waste burning emissions in Northern India: Implications to organic mass-to-organic carbon ratio.

Science.gov (United States)

Rajput, Prashant; Sarin, M M

2014-05-01

This study focuses on characteristics of organic aerosols (polar and non-polar) and total organic mass-to-organic carbon ratio (OM/OC) from post-harvest agricultural-waste (paddy- and wheat-residue) burning emissions in Northern India. Aerosol samples from an upwind location (Patiala: 30.2°N, 76.3°E) in the Indo-Gangetic Plain were analyzed for non-polar and polar fractions of organic carbon (OC1 and OC2) and their respective mass (OM1 and OM2). On average, polar organic aerosols (OM2) contribute nearly 85% of the total organic mass (OM) from the paddy- and wheat-residue burning emissions. The water-soluble-OC (WSOC) to OC2 ratio, within the analytical uncertainty, is close to 1 from both paddy- and wheat-residue burning emissions. However, temporal variability and relatively low WSOC/OC2 ratio (Av: 0.67±0.06) is attributed to high moisture content and poor combustion efficiency during paddy-residue burning, indicating significant contribution (∼30%) of aromatic carbon to OC2. The OM/OC ratio for non-polar (OM1/OC1∼1.2) and polar organic aerosols (OM2/OC2∼2.2), hitherto unknown for open agricultural-waste burning emissions, is documented in this study. The total OM/OC ratio is nearly identical, 1.9±0.2 and 1.8±0.2, from paddy- and wheat-residue burning emissions. Copyright © 2013 Elsevier Ltd. All rights reserved.

Direct determination of the samarium:neodymium ratio in geological materials by inductively coupled plasma quadrupole mass spectrometry with cryogenic desolvation. Comparison with isotope dilution thermal ionization mass spectrometry

International Nuclear Information System (INIS)

Pin, Christian; Telouk, Philippe; Imbert, J.-L.

1995-01-01

A cryogenic desolvation unit in the sample introduction system reduces differences in oxide formation between Sm and Nd to very low levels, enabling the direct, standardless determination of their ratio in bulk solutions by inductively coupled plasma mass spectrometry. The measured values are in reasonably good agreement with those determined by the isotope dilution thermal ionization mass spectrometry (ID-TIMS) reference technique. Although this method cannot, at present, compete with ID-TIMS in terms of precision and accuracy, it is much more straightforward and can be used in geochemistry for studies involving the screening of a large number of samples. (author)

Dietary patterns among girls aged 16–18 years old according to their body mass index and waist-to-hip ratio

Directory of Open Access Journals (Sweden)

Agnieszka Dmitruk

2018-03-01

Full Text Available Aim: The study has been aimed at evaluating dietary patterns of girls aged 16–18 years old in groups identified according to measures such as their body mass index and waist-to-hip ratio. Material and methods: The study covered a total of 151 girls aged 16–18 years old from selected higher secondary schools in Biała Podlaska, Poland. Based on height, weight, waist and hip circumference measurements, body mass index was calculated for each of the participants of the study, allowing to identify two groups: group 1 with normal index and group 2 with overweight or obesity. Also, to determine the type of obesity in the overweight and obese respondents, their waist-to-hip ratio was calculated, identifying the subgroup of girls with abdominal obesity. The respondents’ dietary patterns were identified with the use of a diagnostic survey. The statistical significance of the differences between the participants with normal body mass index and the overweight and obese respondents (including those with abdominal obesity was tested with the chi-square test. Results: Numerous nutritional mistakes/unhealthy dietary patterns were identified in the studied group, largely involving the overweight and obese girls, including those with abdominal obesity. The respondents whose body mass index and waist-to-hip ratio were too high ate fewer meals per day, skipped breakfast more frequently, had their last meal of the day later than 8 p.m., reported less frequent fish and wholemeal bread intake, as opposed to more frequent fast food, sweets and sweetened beverages intake. Conclusion: The unhealthy dietary patterns found in the population of girls with high body mass index and abdominal obesity highlight the need for education in the scope of healthy nutrition aimed both at overweight/obese individuals and their families.

Branching ratio and angular distribution of ejected electrons from Eu 4f76p1/2 n d auto-ionizing states

International Nuclear Information System (INIS)

Wu Xiao-Rui; Shen Li; Zhang Kai; Dai Chang-Jian; Yang Yu-Na

2016-01-01

The branching ratios of ions and the angular distributions of electrons ejected from the Eu 4f 7 6p 1/2 n d auto-ionizing states are investigated with the velocity-map-imaging technique. To populate the above auto-ionizing states, the relevant bound Rydberg states have to be detected first. Two new bound Rydberg states are identified in the region between 41150 cm −1 and 44580 cm −1 , from which auto-ionization spectra of the Eu 4f 7 6p 1/2 n d states are observed with isolated core excitation method. With all preparations above, the branching ratios from the above auto-ionizing states to different final ionic states and the angular distributions of electrons ejected from these processes are measured systematically. Energy dependence of branching ratios and anisotropy parameters within the auto-ionization spectra are carefully analyzed, followed by a qualitative interpretation. (paper)

Application of mass spectrometry based electronic nose and chemometrics for fingerprinting radiation treatment

International Nuclear Information System (INIS)

Gupta, Sumit; Variyar, Prasad S.; Sharma, Arun

2015-01-01

Volatile compounds were isolated from apples and grapes employing solid phase micro extraction (SPME) and subsequently analyzed by GC/MS equipped with a transfer line without stationary phase. Single peak obtained was integrated to obtain total mass spectrum of the volatile fraction of samples. A data matrix having relative abundance of all mass-to-charge ratios was subjected to principal component analysis (PCA) and linear discriminant analysis (LDA) to identify radiation treatment. PCA results suggested that there is sufficient variability between control and irradiated samples to build classification models based on supervised techniques. LDA successfully aided in segregating control from irradiated samples at all doses (0.1, 0.25, 0.5, 1.0, 1.5, 2.0 kGy). SPME-MS with chemometrics was successfully demonstrated as simple screening method for radiation treatment. - Highlights: • Total mass spectra obtained from HS-MS for control and irradiated fruits. • Grapes and apples are chosen for present study. • Total mass spectrum was analyzed by two chemometric techniques (PCA and LDA). • Successful segregation of control and irradiated samples achieved using chemometrics

Evaluating the accuracy of uranium isotope amount ratio measurements performed by a quadrupole and a multi-collector magnetic sector inductively coupled plasma mass spectrometers for nuclear safeguards

International Nuclear Information System (INIS)

Pereira de Oliveira, O. Jr.; Sarkis, J.E.S.; Ponzevera, E.; Alonso, A.; De Bolle, W.; Quetel, C.

2008-01-01

The n(U 235 )/n(U 238 ) isotope amount ratio in a set of samples was measured using two modern analytical techniques: quadrupole inductively coupled plasma mass spectrometry (ICP-QMS) and multi-collector magnetic sector inductively coupled plasma mass spectrometry (MC-ICPMS). The measured ratios were compared to the certified ratios provided by the high accuracy gas source mass spectrometry (GSMS). The components of the uncertainty were identified and their contribution to the combined standard uncertainty was estimated using the recommendations of the ISO-GUM guide. The values of the measurement uncertainty and bias were determined and then compared to the International Target Values for Measurement Uncertainties in Safeguarding Nuclear Materials. It appears that only the measurements performed by MC-ICPMS can meet the stringent requirements of international nuclear safeguards. (authors)

How elevated is the dynamical-to-stellar mass ratio of the ultra-compact dwarf S999?

OpenAIRE

Janz, Joachim; Forbes, Duncan A.; Norris, Mark A.; Strader, Jay; Penny, Samantha J.; Fagioli, Martina; Romanowsky, Aaron J.

2015-01-01

Here we present new Keck ESI high-resolution spectroscopy and deep archival HST/ACS imaging for S999, an ultra-compact dwarf in the vicinity of M87, which was claimed to have an extremely high dynamical-to-stellar mass ratio. Our data increase the total integration times by a factor of 5 and 60 for spectroscopy and imaging, respectively. This allows us to constrain the stellar population parameters for the first time (simple stellar population equivalent age $=7.6^{+2.0}_{-1.6}$ Gyr; $[Z/\\tex...

OGLE-2017-BLG-0373Lb: A Jovian Mass-Ratio Planet Exposes A New Accidental Microlensing Degeneracy

Science.gov (United States)

Skowron, J.; Ryu, Y.-H.; Hwang, K.-H.; Udalski, A.; Mrǎłz, P.; Kozłowski, S.; Soszyński, I.; Pietrukowicz, P.; Szymański, P. K.; Poleski, R.; Ulaczyk, K.; Pawlak, M.; Rybicki, K.; Iwanek, P.; Albrow, M. D.; Chung, S.-J.; Gould, A.; Han, C.; Jung, Y. K.; Shin, I.-G.; Shvartzvald, Y.; Yee, J. C.; Zang, W.; Zhu, W.; Cha, S.-M.; Kim, D.-J.; Kim, H.-W.; Kim, S.-L.; Lee, C.-U.; Lee, D.-J.; Lee, Y.; Park, B.-G.; Pogge, R. W.

2018-03-01

We report the discovery of microlensing planet OGLE-2017-BLG-0373Lb. We show that while the planet-host system has an unambiguous microlens topology, there are two geometries within this topology that fit the data equally well, which leads to a factor 2.5 difference in planet-host mass ratio, i.e., q=1.5×10-3 vs. q=0.6×10-3. We show that this is an "accidental degeneracy" in the sense that it is due to a gap in the data. We dub it "the caustic-chirality degeneracy". We trace the mathematical origins of this degeneracy, which should enable similar degenerate solutions to be easily located in the future. A Bayesian estimate, based on a Galactic model, yields a host mass M=0.25+0.30-0.15 M⊙ at a distance DL=5.9+1.3-1.95 kpc. The lens-source relative proper motion is relatively fast, μ=9 mas/yr, which implies that the host mass and distance can be determined by high-resolution imaging after about 10 years. The same observations could in principle resolve the discrete degeneracy in q, but this will be more challenging.

Determination of uranium in urine - measurement of isotope ratios and quantification by use of inductively coupled plasma mass spectrometry

International Nuclear Information System (INIS)

Krystek, P.; Ritsema, R.

2002-01-01

For analysis of uranium in urine determination of the isotope ratio and quantification were investigated by high-resolution inductively coupled plasma mass spectrometry (HR ICP-MS). The instrument used (ThermoFinniganMAT ELEMENT2) is a single-collector MS and, therefore, a stable sample-introduction system was chosen. The methodical set-up was optimized to achieve the best precision for both the isotope ratio and the total uranium concentration in the urine matrix.Three spiked urine samples from an European interlaboratory comparison were analyzed to determine the 235 U/ 238 U isotope ratio. The ratio was found to be in the range 0.002116 to 0.007222, the latter being the natural uranium isotope ratio. The first ratio indicates the abundance of depleted uranium.The effect of storage conditions and the stability for the matrix urine were investigated by using ''real-life'' urine samples from unexposed persons in the Netherlands. For samples stored under refrigeration and acidified the results (range 0.8 to 5.3 ng L -1 U) were in the normal fluctuation range whereas a decrease in uranium concentration was observed for samples stored at room temperature without acidification. (orig.)

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

Science.gov (United States)

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

Prediction of new Quarks, Generations & low Mass Quarks

Science.gov (United States)

Lach, Theodore

2003-04-01

The CBM (model) of the nucleus has resulted in the prediction of two new quarks, an "up" quark of mass 237.31 MeV/c2 and a "dn" quark of mass 42.392 MeV/c2. These two new predicted quarks helped to determine that the masses of the quarks and leptons are all related by a geometric progression relationship. The mass of each quark or lepton is just the "geometric mean" of two related elementary particles, either in the same generation or in the same family. This numerology predicts the following masses for the electron family: 0.511000 (electron), 7.74 (predicted), 117.3, 1778.4 (tau), 26950.1 MeV. The geometric ratio of this progression is 15.154 (e to the power e). The mass of the tau in this theory agrees very well with accepted values. This theory suggests that all the "dn like" quarks have a mass of just 10X multiples of 4.24 MeV (the mass of the "d" quark). The first 3 "up like" quark masses are 38, 237.31 and 1500 MeV. This theory also predicts a new heavy generation with a lepton mass of 27 GeV, a "dn like" quark of 42.4 GeV, and an "up like" quark of 65 GeV. Significant evidence already exists for the existence of these new quarks, and lepton. Ref. Masses of the Sub-Nuclear Particles, nucl-th/ 0008026, @ http://xxx.lanl.gov. Infinite Energy, Vol 5, issue 30.

Relationship of body mass index and waist to hip ratio measurement with hypertension in young adult medical students

International Nuclear Information System (INIS)

Zafar, S.; Haque, I.U.; Rehman, A.U.

2007-01-01

To examine the BMI profile and waist to hip ratio measurements of young adult medical students of Lahore medical and dental college and its relationship with hypertension. All the students of Lahore medical and dental college were asked to undergo physical examination. Height, weight, waist circumference, hip circumference, systolic and diastolic blood pressure were recorded. The partial correlation coefficient was used to quantify the association between BMI and waist-to-hip circumference ratio with systolic and diastolic blood pressure. Linear regression analysis was used to assess the influence of body mass index and waist-to-hip circumference ratio on the variance of systolic and diastolic BP. Mean BMI was 23.24 (SD+-4.31). Descriptive analysis revealed that 103 (21.3%) of the study population were classified as underweight, 251 (52 %) as normal weight, 99 (20.5%) as overweight, and 30 (6.2 %) as obese. Abdominal adiposity, as measured by increased WHR, was present in 56 subjects (11.59 %). Partial correlation controlled for age revealed strong positive correlation between BMI and WHR for males. 7.24% had high systolic blood pressure, minimum systolic BP was 90 while maximum being 160 mmHg. Same was the value for high diastolic blood pressure i.e. 35 (7.24%), range was from 60 to 100mm Hg. Results of the partial correlation coefficient controlled for age, indicated a significant positive correlation between SBP and DBP. Stepwise linear regression analysis controlled for age revealed that both body mass index and waist-to-hip circumference ratio were independently correlated with both systolic and diastolic blood pressures. The present results suggest that prevalence of overweight and obesity among the medical students is higher than in general population. Those with either higher BMI or central adiposity distribution are potential candidates of increased risk of hypertension and cardiovascular disease. (author)

Time-dependent analysis of visible helium line-ratios for electron temperature and density diagnostic using synthetic simulations on NSTX-U

Energy Technology Data Exchange (ETDEWEB)

Muñoz Burgos, J. M., E-mail: jmunozbu@pppl.gov; Stutman, D.; Tritz, K. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Barbui, T.; Schmitz, O. [Department of Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)

2016-11-15

Helium line-ratios for electron temperature (T{sub e}) and density (n{sub e}) plasma diagnostic in the Scrape-Off-Layer (SOL) and edge regions of tokamaks are widely used. Due to their intensities and proximity of wavelengths, the singlet, 667.8 and 728.1 nm, and triplet, 706.5 nm, visible lines have been typically preferred. Time-dependency of the triplet line (706.5 nm) has been previously analyzed in detail by including transient effects on line-ratios during gas-puff diagnostic applications. In this work, several line-ratio combinations within each of the two spin systems are analyzed with the purpose of eliminating transient effects to extend the application of this powerful diagnostic to high temporal resolution characterization of plasmas. The analysis is done using synthetic emission modeling and diagnostic for low electron density NSTX SOL plasma conditions by several visible lines. Quasi-static equilibrium and time-dependent models are employed to evaluate transient effects of the atomic population levels that may affect the derived electron temperatures and densities as the helium gas-puff penetrates the plasma. The analysis of a wider range of spectral lines will help to extend this powerful diagnostic to experiments where the wavelength range of the measured spectra may be constrained either by limitations of the spectrometer or by other conflicting lines from different ions.

Study of the intrinsic background noise of a quadrupole mass spectrometer

International Nuclear Information System (INIS)

Sysoev, A.A.; Islamov, I.M.; Khafizov, R.S.

1977-01-01

A proper background noise of a quadrupole mass-spectrometer is studied. The main sources of the noise have been analysed as well as their contributions to the overall noise of the device. It is shown that the main contribution is made by the photocurrent of the first dynode of the secondary-electron multiplier from ultraviolet radiation. The construction of the detecting system of the mass-spectrometer is given allowing one to increase the signal-to-noise ratio by a factor of > 500

SM Higgs decay branching ratios and total Higgs width

CERN Multimedia

Daniel Denegri

2001-01-01

Upper: Higgs decay ratios as a function of Higgs mass. The largest branching ratio is not necessarily the most usefull one. The most usefull ones are gamma gamma bbar ZZ and WW as in those modes latter signal to background ratios can be achieved. Lower: Total Higgs decay width versus Higgs mass. At low masses the natural width is extremely small, thus observability depends on instrumental resolution primarily.

First Measurement of the Ratio of Central-Electron to Forward-Electron W Partial Cross Sections in p anti-p Collisions at s**(1/2) = 1.96 TeV

Energy Technology Data Exchange (ETDEWEB)

Abulencia, A.; Adelman, J.; Affolder, T.; Akimoto, T.; Albrow, M.G.; Ambrose, D.; Amerio, S.; Amidei, D.; Anastassov, A.; Anikeev, K.; Annovi, A.; /Taiwan, Inst. Phys.

2007-02-01

We present a measurement of {sigma}(p{bar p} {yields} W) x {Beta}(W {yields} e{nu}) at {radical}s = 1.96 TeV, using electrons identified in the forward region (1.2 < |{eta}| < 2.8) of the CDF II detector. The data correspond to an integrated luminosity of 223 pb{sup -1}. We measure {sigma} x {Beta} = 2796 {+-} 13(stat){sub -90}{sup +95}(syst){+-}162 (lum) pb. Combining this result with a previous CDF measurement obtained using electrons in the central region (|{eta}| {approx}< 1), we present the first measurement of the ratio of central-electron to forward-electron W partial cross sections R{sub exp} = 0.925 {+-} 0.006(stat){+-}0.032(syst), consistent with theoretical predictions using CTEQ and MRST parton distribution functions.

Measurements of total lead concentrations and of lead isotope ratios in whole blood by use of inductively coupled plasma source mass spectrometry

International Nuclear Information System (INIS)

Delves, H.T.; Campbell, M.J.

1988-01-01

Methods are described for the accurate and precise determination of total lead and its isotopic composition in whole blood using inductively coupled plasma source mass spectrometry (ICP-MS). Sensitivities of up to 3 x 10 6 counts s -1 for 208 Pb at a total lead concentration of 5 μmol l -1 (1 μg ml -1 ) enabled total blood lead levels to be measured in 4 min per sample, with a detection limit of 0.072 μmol l -1 (15 μg l -1 ). The agreement between ICP-MS and atomic absorption spectrometry (AAS) for this analysis was excellent: ICP-MS 0.996 x AAS -0.0165 μmol l -1 ; r 0.994. Isotope ratio measurements required 15 min to achieve the required accuracy and precision both of which were generally better than 0.5% for 206 Pb: 207 Pb and 208 Pb: 206 Pb isotopic lead ratios. The ICP-MS data for these ratios in ten quality control blood specimens has a mean bias relative to isotope dilution mass spectrometry of -0.412% for 206 Pb: 207 Pb ratios and of +0.055% for the 208 Pb: 206 Pb ratios. This level of accuracy and that of the total blood lead measurements is sufficient to permit application of these ICP-MS methods to environmental studies. (author)

Computation with Inverse States in a Finite Field FPα: The Muon Neutrino Mass, the Unified Strong-Electroweak Coupling Constant, and the Higgs Mass

International Nuclear Information System (INIS)

Dai, Yang; Borisov, Alexey B.; Boyer, Keith; Rhodes, Charles K.

2000-01-01

The construction of inverse states in a finite field F P α enables the organization of the mass scale with fundamental octets in an eight-dimensional index space that identifies particle states with residue class designations. Conformance with both CPT invariance and the concept of supersymmetry follows as a direct consequence of this formulation. Based on two parameters (P α and g α ) that are anchored on a concordance of physical data, this treatment leads to (1) a prospective mass for the muon neutrino of approximately27.68 meV, (2) a value of the unified strong-electroweak coupling constant α* = (34.26) -1 that is physically defined by the ratio of the electron neutrino and muon neutrino masses, and (3) a see-saw congruence connecting the Higgs, the electron neutrino, and the muon neutrino masses. Specific evaluation of the masses of the corresponding supersymmetric Higgs pair reveals that both particles are superheavy (> 10 18 GeV). No renormalization of the Higgs masses is introduced, since the calculational procedure yielding their magnitudes is intrinsically divergence-free. Further, the Higgs fulfills its conjectured role through the see-saw relation as the particle defining the origin of all particle masses, since the electron and muon neutrino systems, together with their supersymmetric partners, are the generators of the mass scale and establish the corresponding index space. Finally, since the computation of the Higgs masses is entirely determined by the modulus of the field P α , which is fully defined by the large-scale parameters of the universe through the value of the universal gravitational constant G and the requirement for perfect flatness (Omega = 1.0), the see-saw congruence fuses the concepts of mass and space and creates a new unified archetype

Tuning the Electronic Properties, Effective Mass and Carrier Mobility of MoS2 Monolayer by Strain Engineering: First-Principle Calculations

Science.gov (United States)

Phuc, Huynh V.; Hieu, Nguyen N.; Hoi, Bui D.; Hieu, Nguyen V.; Thu, Tran V.; Hung, Nguyen M.; Ilyasov, Victor V.; Poklonski, Nikolai A.; Nguyen, Chuong V.

2018-01-01

In this paper, we studied the electronic properties, effective masses, and carrier mobility of monolayer MoS_2 using density functional theory calculations. The carrier mobility was considered by means of ab initio calculations using the Boltzmann transport equation coupled with deformation potential theory. The effects of mechanical biaxial strain on the electronic properties, effective mass, and carrier mobility of monolayer MoS_2 were also investigated. It is demonstrated that the electronic properties, such as band structure and density of state, of monolayer MoS_2 are very sensitive to biaxial strain, leading to a direct-indirect transition in semiconductor monolayer MoS_2. Moreover, we found that the carrier mobility and effective mass can be enhanced significantly by biaxial strain and by lowering temperature. The electron mobility increases over 12 times with a biaxial strain of 10%, while the carrier mobility gradually decreases with increasing temperature. These results are very useful for the future nanotechnology, and they make monolayer MoS_2 a promising candidate for application in nanoelectronic and optoelectronic devices.

Seasonal and spatial variability of the organic matter-to-organic carbon mass ratios in Chinese urban organic aerosols and a first report of high correlations between aerosol oxalic acid and zinc

Science.gov (United States)

Xing, L.; Fu, T.-M.; Cao, J. J.; Lee, S. C.; Wang, G. H.; Ho, K. F.; Cheng, M.-C.; You, C.-F.; Wang, T. J.

2013-01-01

We calculated the organic matter to organic carbon mass ratios (OM/OC mass ratios) in PM2.5 collected from 14 Chinese cities during summer and winter of 2003 and analyzed the causes for their seasonal and spatial variability. The OM/OC mass ratios were calculated two ways. Using a mass balance method, the calculated OM/OC mass ratios averaged 1.92 ± 0.39 yr-round, with no significant seasonal or spatial variation. The second calculation was based on chemical species analyses of the organic compounds extracted from the PM2.5 samples using dichloromethane/methanol and water. The calculated OM/OC mass ratio in summer was relatively high (1.75 ± 0.13) and spatially-invariant, due to vigorous photochemistry and secondary OA production throughout the country. The calculated OM/OC mass ratio in winter (1.59 ± 0.18) was significantly lower than that in summer, with lower values in northern cities (1.51 ± 0.07) than in southern cities (1.65 ± 0.15). This likely reflects the wider usage of coal for heating purposes in northern China in winter, in contrast to the larger contributions from biofuel and biomass burning in southern China in winter. On average, organic matters constituted 36% and 34% of Chinese urban PM2.5 mass in summer and winter, respectively. We reported, for the first time, high correlations between Zn and oxalic acid in Chinese urban aerosols in summer. This is consistent with the formation of stable Zn oxalate complex in the aerosol phase previously proposed by Furukawa and Takahashi (2011). We found that many other dicarboxylic acids were also highly correlated with Zn in the summer Chinese urban aerosol samples, suggesting that they may also form stable organic complexes with Zn. Such formation may have profound implications for the atmospheric abundance and hygroscopic property of aerosol dicarboxylic acids.

Faithful effective-one-body waveforms of small-mass-ratio coalescing black hole binaries

International Nuclear Information System (INIS)

Damour, Thibault; Nagar, Alessandro

2007-01-01

We address the problem of constructing high-accuracy, faithful analytic waveforms describing the gravitational wave signal emitted by inspiralling and coalescing binary black holes. We work within the effective-one-body (EOB) framework and propose a methodology for improving the current (waveform) implementations of this framework based on understanding, element by element, the physics behind each feature of the waveform and on systematically comparing various EOB-based waveforms with exact waveforms obtained by numerical relativity approaches. The present paper focuses on small-mass-ratio nonspinning binary systems, which can be conveniently studied by Regge-Wheeler-Zerilli-type methods. Our results include (i) a resummed, 3 PN-accurate description of the inspiral waveform, (ii) a better description of radiation reaction during the plunge, (iii) a refined analytic expression for the plunge waveform, (iv) an improved treatment of the matching between the plunge and ring-down waveforms. This improved implementation of the EOB approach allows us to construct complete analytic waveforms which exhibit a remarkable agreement with the exact ones in modulus, frequency, and phase. In particular, the analytic and numerical waveforms stay in phase, during the whole process, within ±1.1% of a cycle. We expect that the extension of our methodology to the comparable-mass case will be able to generate comparably accurate analytic waveforms of direct use for the ground-based network of interferometric detectors of gravitational waves

Chlorine Isotope Effects from Isotope Ratio Mass Spectrometry Suggest Intramolecular C-Cl Bond Competition in Trichloroethene (TCE Reductive Dehalogenation

Directory of Open Access Journals (Sweden)

Stefan Cretnik

2014-05-01

Full Text Available Chlorinated ethenes are prevalent groundwater contaminants. To better constrain (biochemical reaction mechanisms of reductive dechlorination, the position-specificity of reductive trichloroethene (TCE dehalogenation was investigated. Selective biotransformation reactions (i of tetrachloroethene (PCE to TCE in cultures of Desulfitobacterium sp. strain Viet1; and (ii of TCE to cis-1,2-dichloroethene (cis-DCE in cultures of Geobacter lovleyi strain SZ were investigated. Compound-average carbon isotope effects were −19.0‰ ± 0.9‰ (PCE and −12.2‰ ± 1.0‰ (TCE (95% confidence intervals. Using instrumental advances in chlorine isotope analysis by continuous flow isotope ratio mass spectrometry, compound-average chorine isotope effects were measured for PCE (−5.0‰ ± 0.1‰ and TCE (−3.6‰ ± 0.2‰. In addition, position-specific kinetic chlorine isotope effects were determined from fits of reactant and product isotope ratios. In PCE biodegradation, primary chlorine isotope effects were substantially larger (by −16.3‰ ± 1.4‰ (standard error than secondary. In TCE biodegradation, in contrast, the product cis-DCE reflected an average isotope effect of −2.4‰ ± 0.3‰ and the product chloride an isotope effect of −6.5‰ ± 2.5‰, in the original positions of TCE from which the products were formed (95% confidence intervals. A greater difference would be expected for a position-specific reaction (chloride would exclusively reflect a primary isotope effect. These results therefore suggest that both vicinal chlorine substituents of TCE were reactive (intramolecular competition. This finding puts new constraints on mechanistic scenarios and favours either nucleophilic addition by Co(I or single electron transfer as reductive dehalogenation mechanisms.

Dissociation mechanism of HNIW ions investigated by chemical ionization and electron impact mass spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Yang, Rongjie; Xiao, Hemiao [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China)

2006-04-15

Chemical Ionization (CI) with Collision-Induced Dissociation (CID) spectroscopy and Electron Impacting (EI) with metastable Mass analyzed Ion Kinetic Energy (MIKE) spectroscopy have been applied to study ionic dissociations of Hexanitrohexaazaisowurtzitane (HNIW). Similarities and differences between EI/MIKE and CI/CID mass spectra of HNIW were analyzed. In EI mass spectra, the ions [HNIW-n NO{sub 2}]{sup +} (n=2-5), such as the ion at m/z 347, were less frequent (1-2% relative abundance), but in CI mass spectra, these ions were very abundant. For some ions of large molar mass from HNIW, their dissociations pathways from parent ions to daughter ions were built according to CID and MIKE spectra. Molecular ions of HNIW with a protonated nitro group at five-member ring seem more stable than at six-member ring. The HNIW ions losing five of six nitro groups are very stable based on CID spectra, which agrees with some research results for thermal decomposition of HNIW in literature. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

Time dependent thermal treatment of oxidized MWCNTs studied by the electron and mass spectroscopy methods

Czech Academy of Sciences Publication Activity Database

Stobinski, L.; Lesiak, B.; Zemek, Josef; Jiříček, Petr

2012-01-01

Roč. 258, č. 20 (2012), s. 7912-7917 ISSN 0169-4332 Institutional research plan: CEZ:AV0Z10100521 Keywords : MWCNTs * ox-MWCNTs * functional materials * electron spectroscopy * mass spectroscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.112, year: 2012

Chlorine loss and mass loss from polyvinylchloride and polyvinylidenchloride under the electron beam

International Nuclear Information System (INIS)

Lindberg, K.A.H.; Bertilsson, H.E.

1985-01-01

The loss of chlorine during the irradiation of PVC and PVDC in the electron microscope has been measured by the decay of the X-ray chlorine Kα signal. A number of factors affecting the measured beam damage curves have been considered and the experimental errors reduced to +- 10%. The results show that the chlorine decay curves can be best described by the sum of two exponentials, corresponding to the two different chlorine decay processes, these being: the dehydrochlorination of the polymer molecules and the dehydrochlorination of the polyene structure formed by the beam damage. The higher initial chlorine content of PVDC compared to PVC will result in a larger amount of chlorine atoms reacting with the polyene structure, which is more stable in the electron beam than the undamaged polymer. The chlorine loss, measured by X-ray analysis, has been compared to the mass loss, measured by energy loss analysis, and also with the volume changes of isolated spherical PVC particles. It has been concluded that the mass loss is almost entirely due to chlorine loss and that the residual structure has a density similar to the undamaged PVC. (author)

Modeling Nearly Spherical Pure-bulge Galaxies with a Stellar Mass-to-light Ratio Gradient under the ΛCDM and MOND Paradigms. I. Methodology, Dynamical Stellar Mass, and Fundamental Mass Plane

Science.gov (United States)

Chae, Kyu-Hyun; Bernardi, Mariangela; Sheth, Ravi K.

2018-06-01

We carry out spherical Jeans modeling of nearly round pure-bulge galaxies selected from the ATLAS3D sample. Our modeling allows for gradients in the stellar mass-to-light ratio (M ⋆/L) through analytic prescriptions parameterized with a “gradient strength” K introduced to accommodate any viable gradient. We use a generalized Osipkov–Merritt model for the velocity dispersion (VD) anisotropy. We produce Monte Carlo sets of models based on the stellar VD profiles under both the ΛCDM and MOND paradigms. Here, we describe the galaxy data, the empirical inputs, and the modeling procedures of obtaining the Monte Carlo sets. We then present the projected dynamical stellar mass, {M}\\star {{e}}, within the effective radius R e, and the fundamental mass plane (FMP) as a function of K. We find the scaling of the K-dependent mass with respect to the ATLAS3D reported mass as: {log}}10[{M}\\star {{e}}(K)/{M}\\star {{e}}{{A}3{{D}}}]=a\\prime +b\\prime K with a‧ = ‑0.019 ± 0.012 and b‧ = ‑0.18 ± 0.02 (ΛCDM), or a‧ = ‑0.023 ± 0.014 and b‧ = ‑0.23 ± 0.03 (MOND), for 0 ≤ K expectation and only the zero-point scales with K. The median value of K for the ATLAS3D galaxies is ={0.53}-0.04+0.05. We perform a similar analysis of the much larger SDSS DR7 spectroscopic sample. In this case, only the VD within a single aperture is available, so we impose the additional requirement that the VD slope be similar to that in the ATLAS3D galaxies. Our analysis of the SDSS galaxies suggests a positive correlation of K with stellar mass.

Steroid isotopic standards for gas chromatography-combustion isotope ratio mass spectrometry (GCC-IRMS).

Science.gov (United States)

Zhang, Ying; Tobias, Herbert J; Brenna, J Thomas

2009-03-01

Carbon isotope ratio (CIR) analysis of urinary steroids using gas chromatography-combustion isotope ratio mass spectrometry (GCC-IRMS) is a recognized test to detect illicit doping with synthetic testosterone. There are currently no universally used steroid isotopic standards (SIS). We adapted a protocol to prepare isotopically uniform steroids for use as a calibrant in GCC-IRMS that can be analyzed under the same conditions as used for steroids extracted from urine. Two separate SIS containing a mixture of steroids were created and coded CU/USADA 33-1 and CU/USADA 34-1, containing acetates and native steroids, respectively. CU/USADA 33-1 contains 5alpha-androstan-3beta-ol acetate (5alpha-A-AC), 5alpha-androstan-3alpha-ol-17-one acetate (androsterone acetate, A-AC), 5beta-androstan-3alpha-ol-11, 17-dione acetate (11-ketoetiocholanolone acetate, 11k-AC) and 5alpha-cholestane (Cne). CU/USADA 34-1 contains 5beta-androstan-3alpha-ol-17-one (etiocholanolone, E), 5alpha-androstan-3alpha-ol-17-one (androsterone, A), and 5beta-pregnane-3alpha, 20alpha-diol (5betaP). Each mixture was prepared and dispensed into a set of about 100 ampoules using a protocol carefully designed to minimize isotopic fractionation and contamination. A natural gas reference material, NIST RM 8559, traceable to the international standard Vienna PeeDee Belemnite (VPDB) was used to calibrate the SIS. Absolute delta(13)C(VPDB) and Deltadelta(13)C(VPDB) values from randomly selected ampoules from both SIS indicate uniformity of steroid isotopic composition within measurement reproducibility, SD(delta(13)C)<0.2 per thousand. This procedure for creation of isotopic steroid mixtures results in consistent standards with isotope ratios traceable to the relevant international reference material.

Binary neutron star mergers and short gamma-ray bursts: Effects of magnetic field orientation, equation of state, and mass ratio

Science.gov (United States)

Kawamura, Takumu; Giacomazzo, Bruno; Kastaun, Wolfgang; Ciolfi, Riccardo; Endrizzi, Andrea; Baiotti, Luca; Perna, Rosalba

2016-09-01

We present fully general-relativistic magnetohydrodynamic simulations of the merger of binary neutron star (BNS) systems. We consider BNSs producing a hypermassive neutron star (HMNS) that collapses to a spinning black hole (BH) surrounded by a magnetized accretion disk in a few tens of ms. We investigate whether such systems may launch relativistic jets and hence power short gamma-ray bursts. We study the effects of different equations of state (EOSs), different mass ratios, and different magnetic field orientations. For all cases, we present a detailed investigation of the matter dynamics and of the magnetic field evolution, with particular attention to its global structure and possible emission of relativistic jets. The main result of this work is that we observe the formation of an organized magnetic field structure. This happens independently of EOS, mass ratio, and initial magnetic field orientation. We also show that those models that produce a longer-lived HMNS lead to a stronger magnetic field before collapse to a BH. Such larger fields make it possible, for at least one of our models, to resolve the magnetorotational instability and hence further amplify the magnetic field in the disk. However, by the end of our simulations, we do not (yet) observe a magnetically dominated funnel nor a relativistic outflow. With respect to the recent simulations of Ruiz et al. [Astrophys. J. 824, L6 (2016)], we evolve models with lower and more plausible initial magnetic field strengths and (for computational reasons) we do not evolve the accretion disk for the long time scales that seem to be required in order to see a relativistic outflow. Since all our models produce a similar ordered magnetic field structure aligned with the BH spin axis, we expect that the results found by Ruiz et al. (who only considered an equal-mass system with an ideal fluid EOS) should be general and—at least from a qualitative point of view—independent of the mass ratio, magnetic field

Effects of electron inertia in capacitively coupled radio frequency discharges

International Nuclear Information System (INIS)

Xiang Nong

2004-01-01

The effects of the electron inertia on the plasma and sheath dynamics in capacitively coupled rf discharges with frequency ωω pi are investigated (here, ω and ω pi are the rf frequency and bulk ion plasma frequency, respectively). It is found that the effects of the electron inertia on the plasma density and ion velocity in the quasi-neutral region depend on the ratio of the amplitudes of the discharge current I rf and ion current I B =en 0 C s (here, e is the unit charge, n 0 is the plasma density at center, and C s is the ion sound speed). If the ratio is small so that I rf /I B √(m i /m e ) (here, m i and m e are ion and electron masses, respectively), the ion and time-averaged electron densities, ion velocity, and electric fields are little affected by the electron inertia. Otherwise, the effects of the electron inertia are significant. It is also shown that the assumption that the electrons obey the Boltzmann distribution in the sheath is invalid when the electron flux flowing to the electrode is significant

Recent Developments in Trace, Ultratrace and Isotope Ratio Measurements in Inductively Coupled Plasma Mass Spectrometry

International Nuclear Information System (INIS)

Zahran, N. F.

2004-01-01

Inductively coupled plasma mass spectrometry (ICP-MS) and Laser Ablation (LA-ICP-MS) are recent techniques for trace, ultratrace and isotope ratio measurements. Main features of these techniques and their figure of merit and capabilities are discussed. An overview of ICP-MS instrument is presented in addition to its precision, accuracy and detection limits. Uses of ICP-MS in environmental monitoring in some cases for detection of some radio nuclides are presented. Two geological applications namely, zircon grains analysis and age dating of Rb-Sr method are presented. Zn elemental and isotopic analyses in blood and serum as a biological application is shown. (Author)

Measurement of the W Boson Mass with the D0 Run II Detector using the Electron P(T) Spectrum

Energy Technology Data Exchange (ETDEWEB)

Andeen, Jr., Timothy R. [Northwestern Univ., Evanston, IL (United States)

2008-06-01

This thesis is a description of the measurement of the W boson mass using the D0 Run II detector with 770 pb^-1 of p$\\bar{p}$ collision data. These collisions were produced by the Tevatron at √s = 1.96 TeV between 2002 and 2006. We use a sample of W → ev and Z → ee decays to determine the W boson mass with the transverse momentum distribution of the electron and the transverse mass distribution of the boson. We measure M_W = 80340 ± 37 (stat.) ± 26 (sys. theo.) ± 51 (sys. exp.) MeV = 80340 ± 68 MeV with the transverse momentum distribution of the electron and M_W = 80361 ± 28 (stat.) ± 17 (sys. theo.) ± 51 (sys. exp.) MeV = 80361 ± 61 MeV with the transverse mass distribution.

VERY LOW MASS STELLAR AND SUBSTELLAR COMPANIONS TO SOLAR-LIKE STARS FROM MARVELS. I. A LOW-MASS RATIO STELLAR COMPANION TO TYC 4110-01037-1 IN A 79 DAY ORBIT

International Nuclear Information System (INIS)

Wisniewski, John P.; Agol, Eric; Barnes, Rory; Ge, Jian; De Lee, Nathan; Fleming, Scott W.; Lee, Brian L.; Chang, Liang; Crepp, Justin R.; Eastman, Jason; Gaudi, B. Scott; Esposito, Massimiliano; Gonzalez Hernandez, Jonay I.; Prieto, Carlos Allende; Ghezzi, Luan; Da Costa, Luiz N.; Porto De Mello, G. F.; Stassun, Keivan G.; Cargile, Phillip; Bizyaev, Dmitry

2012-01-01

TYC 4110-01037-1 has a low-mass stellar companion, whose small mass ratio and short orbital period are atypical among binary systems with solar-like (T eff ∼ ☉ and radius of 0.99 ± 0.18 R ☉ . We analyze 32 radial velocity (RV) measurements from the SDSS-III MARVELS survey as well as 6 supporting RV measurements from the SARG spectrograph on the 3.6 m Telescopio Nazionale Galileo telescope obtained over a period of ∼2 years. The best Keplerian orbital fit parameters were found to have a period of 78.994 ± 0.012 days, an eccentricity of 0.1095 ± 0.0023, and a semi-amplitude of 4199 ± 11 m s –1 . We determine the minimum companion mass (if sin i = 1) to be 97.7 ± 5.8 M Jup . The system's companion to host star mass ratio, ≥0.087 ± 0.003, places it at the lowest end of observed values for short period stellar companions to solar-like (T eff ∼< 6000 K) stars. One possible way to create such a system would be if a triple-component stellar multiple broke up into a short period, low q binary during the cluster dispersal phase of its lifetime. A candidate tertiary body has been identified in the system via single-epoch, high contrast imagery. If this object is confirmed to be comoving, we estimate it would be a dM4 star. We present these results in the context of our larger-scale effort to constrain the statistics of low-mass stellar and brown dwarf companions to FGK-type stars via the MARVELS survey.

Performance of the Fuel Conditioning Facility electronic in-cell mass balances

International Nuclear Information System (INIS)

Orechwa, Y.; Bucher, R.G.

1996-01-01

An approach to error estimation and measurement control in the analysis of the balance measurements of mass standards on the in-cell electronic mass balances of the Fuel Conditioning Facility is presented. In light of measurement data from one year of operation, the algorithms proposed are evaluated. The need to take into account the effects of facility operations on the estimates of measurement uncertainty is demonstrated. In the case of a newly installed balance, where no historical data exists, an ad hoc procedure of adding a term which takes into account the operational variability is proposed. This procedure allows a sufficiently long operation so as to collect data for the estimate of the contribution of operational effects to the uncertainty estimate. An algorithm for systematically taking into account historical data is developed and demonstrated for two balances over two calibration periods. The algorithm, both asymptotically and in the two samples cases, has the necessary desirable properties for estimating the uncertainty in the measurements of the balances

An experiment to measure the electron neutrino mass using a cryogenic tritium source

International Nuclear Information System (INIS)

Fackler, O.; Jeziorski, B.; Kolos, W.; Monkhorst, H.; Mugge, M.; Sticker, H.; Szalewicz, K.; White, R.M.; Woerner, R.

1985-01-01

An experiment has been performed to determine the electron neutrino mass with the precision of a few eV by measuring the tritium beta decay energy distribution near the endpoint. Key features of the experiment are a 2 eV resolution electrostatic spectrometer and a high-activity frozen tritium source. It is important that the source have electronic wavefunctions which can be accurately calculated. These calculations have been made for tritium and the HeT + daughter ion and allow determination of branching fractions to 0.1% and energy of the excited states to 0.1 eV. The excited final molecular state calculations and the experimental apparatus are discussed. 4 refs., 5 figs

Effective electron mass and phonon modes in n-type hexagonal InN

Science.gov (United States)

Kasic, A.; Schubert, M.; Saito, Y.; Nanishi, Y.; Wagner, G.

2002-03-01

Infrared spectroscopic ellipsometry and micro-Raman scattering are used to study vibrational and electronic properties of high-quality hexagonal InN. The 0.22-μm-thick highly n-conductive InN film was grown on c-plane sapphire by radio-frequency molecular-beam epitaxy. Combining our results from the ellipsometry data analysis with Hall-effect measurements, the isotropically averaged effective electron mass in InN is determined as 0.14m0. The resonantly excited zone center E1 (TO) phonon mode is observed at 477 cm-1 in the ellipsometry spectra. Despite the high electron concentration in the film, a strong Raman mode occurs in the spectral range of the unscreened A1(LO) phonon. Because an extended carrier-depleted region at the sample surface can be excluded from the ellipsometry-model analysis, we assign this mode to the lower branch of the large-wave-vector LO-phonon-plasmon coupled modes arising from nonconserving wave-vector scattering processes. The spectral position of this mode at 590 cm-1 constitutes a lower limit for the unscreened A1(LO) phonon frequency.

Intensity ratio curve analysis of small renal masses on T2-weighted magnetic resonance imaging: Differentiation of fat-poor angiomyolipoma from renal cell carcinoma.

Science.gov (United States)

Moriyama, Shingo; Yoshida, Soichiro; Tanaka, Hajime; Tanaka, Hiroshi; Yokoyama, Minato; Ishioka, Junichiro; Matsuoka, Yoh; Saito, Kazutaka; Kihara, Kazunori; Fujii, Yasuhisa

2018-03-25

To assess the diagnostic ability of a pixel intensity-based analysis in evaluating the magnetic resonance imaging characteristics of small renal masses, especially in differentiating fat-poor angiomyolipoma from renal cell carcinoma. T2-weighted images from 121 solid small renal masses (ratio curve was plotted using intensity ratios, which were ratios of signal intensities of tumor pixels (each pixel along a linear region of interest drawn across the renal tumor on T2-weighted image) to the signal intensity of a normal renal cortex. The diagnostic ability of the intensity ratio curve analysis was evaluated. The tumors were classified into three types: intensity ratio fat-poor angiomyolipoma (n = 19) with no pseudocapsule, iso-low intensity and no heterogeneity; intensity ratio clear cell renal cell carcinoma (n = 76) with a pseudocapsule, iso-high intensity and heterogeneity; and other type of intensity ratio (n = 26), including tumors that did not fall into the above two categories. The sensitivity/specificity/accuracy of the intensity ratio curve analysis in diagnosing fat-poor angiomyolipoma was 93%/94%/94%, respectively. When the intensity ratio curve analysis was applied only to the tumor with undetermined radiological diagnosis, the sensitivity for diagnosing fat-poor angiomyolipoma compared with subjective reading alone significantly improved (93% vs 50%; P = 0.014). Our novel semiquantitative model for combined assessment of key features of fat-poor angiomyolipoma, including low intensity, homogeneity and absence of a pseudocapsule on T2-weighted image, might make diagnosis of fat-poor angiomyolipoma more accurate. © 2018 The Japanese Urological Association.

Determination of strontium and lead isotope ratios of grains using high resolution inductively coupled plasma mass spectrometer with single collector

International Nuclear Information System (INIS)

Shinozaki, Miyuki; Ariyama, Kaoru; Kawasaki, Akira; Hirata, Takafumi

2010-01-01

A method for determining strontium and lead isotope ratios of grains was developed. The samples investigated in this study were rice, barley and wheat. The samples were digested with nitric acid and hydrogen peroxide, and heated in a heating block. Strontium and lead were separated from the matrix by adding an acid digested solution into a column packed with Sr resin, which has selectivity for the absorption of strontium and lead. Strontium and lead isotope ratios were determined using a high-resolution inductively coupled plasma mass spectrometer (HR-ICP-MS) with a single collector. The intraday relative standard deviations of 87 Sr/ 86 Sr and lead isotope ratios ( 204 Pb/ 206 Pb, 207 Pb/ 206 Pb, 208 Pb/ 206 Pb) by HR-ICP-MS measurements were < 0.06% and around 0.1%, respectively. This method enabled us to determine strontium and lead isotope ratios in two days. (author)

Electronic properties of epitaxial 6H silicon carbide

International Nuclear Information System (INIS)

Wessels, B.W.; Gatos, H.C.

1977-01-01

The electrical conductivity and Hall coefficient were measured in the temperature range from 78 to 900 K for n-type epitaxially grown 6H silicon carbide. A many-valley model of the conduction band was used in the analysis of electron concentration as a function of temperature. From this analysis, the density of states mass to the free electron mass ratio per ellipsoid was calculated to be 0.45. It was estimated that the constant energy surface of the conduction band consists of three ellipsoids. The ionization energy of the shallowest nitrogen donor was found to be 105 meV, when the valley-orbit interaction was taken into account. The electron scattering mechanisms in the epitaxial layers were analyzed and it was shown that the dominant mechanism limiting electron mobility at high temperatures is inter-valley scattering and at low temperatures (200K), impurity and space charge scattering. A value of 360 cm 2 /V sec was calculated for the maximum room temperature Hall mobility expected for electrons in pure 6H SiC. The effect of epitaxial growth temperature on room temperature Hall mobility was also investigated. (author)

Profiling of new psychoactive substances (NPS) by using stable isotope ratio mass spectrometry (IRMS): study on the synthetic cannabinoid 5F-PB-22.

Science.gov (United States)

Münster-Müller, S; Scheid, N; Holdermann, T; Schneiders, S; Pütz, M

2018-05-21

In this paper results of a pilot study on the profiling of the synthetic cannabinoid receptor agonist 5F-PB-22 (5F-QUPIC, pentylfluoro-1H-indole-3-carboxylic acid-8-quinolinyl ester) via isotope ratio mass spectrometry are presented. It is focused on δ 13 C, δ 15 N and δ 2 H isotope ratios, which are determined using elemental analyser (EA) and high temperature elemental analyser (TC/EA) coupled to an isotope ratio mass spectrometer (IRMS). By means of a sample of pure material of 5F-PB-22 it is shown that the extraction of 5F-PB-22 from herbal material, a rapid clean-up procedure, or preparative column chromatography had no influences on the isotope ratios. Furthermore, 5F-PB-22 was extracted from fourteen different herbal blend samples ("Spice products" from police seizures) and analysed via IRMS, yielding three clusters containing seven, five and two samples, distinguishable through their isotopic composition, respectively. It is assumed that herbal blends in each cluster have been manufactured from individual batches of 5F-PB-22. This article is protected by copyright. All rights reserved.

Discrimination of geographical origin of lentils (Lens culinaris Medik.) using isotope ratio mass spectrometry combined with chemometrics.

Science.gov (United States)

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 (porigin 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

Polarization of electron-positron vacuum by strong magnetic field in theory with fundamental mass

International Nuclear Information System (INIS)

Kadyshevskij, V.G.; ); Rodionov, V.N.

2003-01-01

The exact Lagrangian function of the intensive constant magnetic field, replacing the Heisenberg-Euler Lagrangian in the traditional quantum electrodynamics, is calculated within the frames of the theory with the fundamental mass in the single-loop approximation. It is established that the obtained generalization of the Lagrangian function is substantial by arbitrary values of the magnetic field. The calculated Lagrangian in the weak field coincides with the known Heisenberg-Euler formula. The Lagrangian dependence on the field in the extremely strong fields completely disappears and it tends in this area to the threshold value, which is determined by the fundamental and lepton mass ratio [ru

Study of electron beam effects on surfaces using x-ray photoelectron spectroscopy (XPS) and secondary ion mass spectroscopy (SIMS)

International Nuclear Information System (INIS)

Gettings, M.; Coad, J.P.

1976-02-01

Discrepancies in the surface analyses of oxidised or heavily contaminated materials have been observed between X-ray Photoelectron Spectroscopy (XPS) and techniques using electron beams (primarily Auger Electron Spectroscopy (AES)). These discrepancies can be ascribed to the influence of the primary electron beam and to illustrate the various types of electron effects different materials were analysed using XPS and Secondary Ion Mass Spectroscopy (SIMS) before and after large area electron bombardment. The materials used included chrome and stainless steels, nickel, platinum, glass and brass. (author)

The impact of realistic models of mass segregation on the event rate of extreme-mass ratio inspirals and cusp re-growth

International Nuclear Information System (INIS)

Amaro-Seoane, Pau; Preto, Miguel

2011-01-01

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 . ∼ 6 M o-dot (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 ∼10 2 -7 x 10 2 sbh's (EMRIs detected by LISA over a mission lifetime of 2 or 5

Diagnosis of mildly relativistic electron velocity distributions by electron cyclotron emission in the Alcator C tokamak

International Nuclear Information System (INIS)

Kato, K.

1986-09-01

Mildly relativistic electron velocity distributions are diagnosed from measurements of the first few electron cyclotron emission harmonics in the Alcator C tokamak. The approach employs a vertical viewing chord through the center of the tokamak plasma terminating at a compact, high-performance viewing dump. The cyclotron emission spectra obtained in this way are dominated by frequency downshifts due to the relativistic mass increase, which discriminates the electrons by their total energy. In this way a one-to-one correspondence between the energy and the emission frequency is accomplished in the absence of harmonic superpositions. The distribution, described by f/sub p/, the line-averaged phase space density, and Λ, the anisotropy factor, is determined from the ratio of the optically thin harmonics or polarizations. Diagnosis of spectra in the second and the third harmonic range of frequencies obtained during lower hybrid heating, current drive, and low density ohmic discharges are carried out, using different methods depending on the degree of harmonic superposition present in the spectrum and the availability of more than one ratio measurement. Discussions of transient phenomena, the radiation temperature measurement from the optically thick first harmonic, and the measurements compared to the angular hard x-ray diagnostic results illuminate the capabilities of the vertically viewing electron cyclotron emission diagnostic

Standard model false vacuum inflation: correlating the tensor-to-scalar ratio to the top quark and Higgs boson masses.

Science.gov (United States)

Masina, Isabella; Notari, Alessio

2012-05-11

For a narrow band of values of the top quark and Higgs boson masses, the standard model Higgs potential develops a false minimum at energies of about 10(16)  GeV, where primordial inflation could have started in a cold metastable state. A graceful exit to a radiation-dominated era is provided, e.g., by scalar-tensor gravity models. We pointed out that if inflation happened in this false minimum, the Higgs boson mass has to be in the range 126.0±3.5  GeV, where ATLAS and CMS subsequently reported excesses of events. Here we show that for these values of the Higgs boson mass, the inflationary gravitational wave background has be discovered with a tensor-to-scalar ratio at hand of future experiments. We suggest that combining cosmological observations with measurements of the top quark and Higgs boson masses represent a further test of the hypothesis that the standard model false minimum was the source of inflation in the universe.

Water swelling properties of the electron beam irradiated PVA-g-AAc hydrogels

Energy Technology Data Exchange (ETDEWEB)

Wang, Qingguo, E-mail: qwang@qust.edu.cn [Key Laboratory of Rubber-Plastics of Ministry of Education, Qingdao University of Science and Technology, Qingdao 266042 (China); Shandong Provincial Key Laboratory of Rubber-Plastics, Qingdao 266042 (China); Zhou, Xue; Zeng, Jinxia; Wang, Jizeng [Key Laboratory of Rubber-Plastics of Ministry of Education, Qingdao University of Science and Technology, Qingdao 266042 (China)

2016-02-01

In this paper, the electron beam irradiation technology being more suitable for the industry application is explored to fabricate the acrylic acid (AAc) monomer-grafted polyvinyl alcohol (PVA-g-AAc) hydrogels. ATR-IR spectra of the PVA-g-AAc hydrogels shows an obvious absorption peak of the −C=O group at 1701 cm{sup −1}, indicating that the AAc monomers were grafted onto the PVA macromolecules. This paper also studied some effects of the mass ratio of PVA/AAc, pH of buffer solution and irradiation dosage on the water swelling properties of the electron beam irradiated PVA-g-AAc hydrogels. The water swelling ratio of PVA-g-AAc hydrogels decreases with increased irradiation dosage and mass ratio of PVA/AAc, whereas swelling ratio increases with increased pH of buffer solution and soaking time. The water-swelling behavior of PVA-g-AAc hydrogels occurred easily in an alkaline environment, particularly in a buffer solution with pH 9.2. Both PVA-g-AAc hydrogels (PVA/AAc = 1/5, w/w) irradiated with 5 kilogray (kGy) and PVA-g-AAc hydrogels (PVA/AAc = 1/1, w/w) irradiated with 15 kGy could easily absorb water and lead to high water swelling ratios (up to about 600%), which are potential candidates to meet the requirements for some biomedical applications.

Broadband non-selective excitation of plutonium isotopes for isotope ratio measurements in resonance ionization mass spectrometry: a theoretical study.

Science.gov (United States)

Sankari, M

2012-10-15

Making isotope ratio measurements with minimum isotope bias has always been a challenging task to mass spectrometrists, especially for the specific case of plutonium, owing to the strategic importance of the element. In order to use resonance ionization mass spectrometry (RIMS) as a tool for isotope ratio measurements, optimization of the various laser parameters and other atomic and system parameters is critical to minimize isotopic biases. Broadband simultaneous non-selective excitation of the isotopes of plutonium in the triple resonance excitation scheme with λ(1) = 420.77 nm, λ(2) = 847.28 nm, and λ(3) = 767.53 nm based on density matrix formalism has been theoretically computed for the determination of isotope ratios. The effects of the various laser parameters and other factors such as the atomization temperature and the dimensions of the atomic beam on the estimation of isotope ratios were studied. The effects of Doppler broadening, and time-dependent excitation parameters such as Rabi frequencies, ionization rate and the effect of non-Lorenztian lineshape have all been incorporated. The average laser powers and bandwidths for the three-excitation steps were evaluated for non-selective excitation. The laser intensity required to saturate the three-excitation steps were studied. The two-dimensional lineshape contour and its features were investigated, while the reversal of peak asymmetry of two-step and two-photon excitation peaks under these conditions is discussed. Optimized powers for the non-selective ionization of the three transitions were calculated as 545 mW, 150 mW and 545 mW and the laser bandwidth for all the three steps was ~20 GHz. The isotopic bias between the resonant and off-resonant isotope under the optimized conditions was no more than 9%, which is better than an earlier reported value. These optimized laser power and bandwidth conditions are better than in the earlier experimental work since these comprehensive calculations yield

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

International Nuclear Information System (INIS)

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

2010-01-01

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.

Mass spectroscopy of recoiled ions, secondary ion mass spectroscopy, and Auger electron spectroscopy investigation of Y2O3-stabilized ZrO2(100) and (110)

International Nuclear Information System (INIS)

Herman, G.S.; Henderson, M.A.; Starkweather, K.A.; McDaniel, E.P.

1999-01-01

We have studied the (100) and (110) surfaces of yttria-stabilized cubic ZrO 2 using Auger electron spectroscopy, low energy electron diffraction (LEED), direct recoil spectroscopy, mass spectroscopy of recoiled ions (MSRI), and secondary ion mass spectroscopy (SIMS). The concentration of yttrium at the surface was weakly influenced by the surface structure under the experimental conditions investigated. Both MSRI and SIMS indicated a more enhanced yttrium signal than zirconium signal at the surface compared to the respective bulk concentrations. The surfaces were not very well ordered as indicated by LEED. The yttria-stabilized cubic ZrO 2 single crystal surfaces may not be a suitable model material for pure phase ZrO 2 surfaces due to significant yttria concentrations at the surface. copyright 1999 American Vacuum Society

First-principle study of the electronic band structure and the effective mass of the ternary alloy GaxIn1-xP

Science.gov (United States)

Yang, H. Q.; Song, T. L.; Liang, X. X.; Zhao, G. J.

2015-01-01

In this work, the electronic band structure and the effective mass of the ternary alloy GaxIn1-xP are studied by the first principle calculations. The software QUANTUM ESPRESSO and the generalized gradient approximation (GGA) for the exchange correlations have been used in the calculations. We calculate the lattice parameter, band gap and effective mass of the ternary alloy GaxIn1-xP for the Ga composition x varying from 0.0 to 1.0 by the step of 0.125. The effect of the Ga composition on the lattice parameter and the electronic density of states are discussed. The results show that the lattice parameter varies with the composition almost linearly following the Vegard's law. A direct-to-indirect band-gap crossover is found to occur close to x = 0.7. The effective masses are also calculated at Γ(000) high symmetry point along the [100] direction. The results show that the band gap and the electron effective mass vary nonlinearly with composition x.

Macrocluster desorption effect caused by single MCI: charges of gold clusters (2-20 nm) desorbed due to electronic processes induced by fission fragment bombardment in nanodispersed gold targets

International Nuclear Information System (INIS)

Baranov, I.; Jarmiychuk, S.; Kirillov, S.; Novikov, A.; Obnorskii, V.; Pchelintsev, A.; Wien, K.; Reimann, C.

1999-01-01

In this work the charge state of the negatively charged gold nanocluster ions (2-20 nm) that were desorbed from nanodispersed gold islet targets by 252 Cf fission fragments via electronic processes is studied. Mean cluster charge was calculated as a ratio of mean cluster mass to mean mass-to-charge ratio . Cluster masses were measured by means of a collector technique employing transmission electron microscopy and scanning force microscopy, while m/q was measured by means of a tandem TOF-spectrometer. It is shown that the nanocluster ions are mostly multiply charged (2-16e) and the charge increases non-linearly with the cluster size. The results are discussed

Electron beam-plasma interaction and electron-acoustic solitary waves in a plasma with suprathermal electrons

Science.gov (United States)

Danehkar, A.

2018-06-01

Suprathermal electrons and inertial drifting electrons, so called electron beam, are crucial to the nonlinear dynamics of electrostatic solitary waves observed in several astrophysical plasmas. In this paper, the propagation of electron-acoustic solitary waves (EAWs) is investigated in a collisionless, unmagnetized plasma consisting of cool inertial background electrons, hot suprathermal electrons (modeled by a κ-type distribution), and stationary ions. The plasma is penetrated by a cool electron beam component. A linear dispersion relation is derived to describe small-amplitude wave structures that shows a weak dependence of the phase speed on the electron beam velocity and density. A (Sagdeev-type) pseudopotential approach is employed to obtain the existence domain of large-amplitude solitary waves, and investigate how their nonlinear structures depend on the kinematic and physical properties of the electron beam and the suprathermality (described by κ) of the hot electrons. The results indicate that the electron beam can largely alter the EAWs, but can only produce negative polarity solitary waves in this model. While the electron beam co-propagates with the solitary waves, the soliton existence domain (Mach number range) becomes narrower (nearly down to nil) with increasing the beam speed and the beam-to-hot electron temperature ratio, and decreasing the beam-to-cool electron density ratio in high suprathermality (low κ). It is found that the electric potential amplitude largely declines with increasing the beam speed and the beam-to-cool electron density ratio for co-propagating solitary waves, but is slightly decreased by raising the beam-to-hot electron temperature ratio.

The Use of Low Temperature Detectors for Direct Measurements of the Mass of the Electron Neutrino

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