scholarly journals Fundamental parameters of B type stars

2014 ◽  
Vol 9 (S307) ◽  
pp. 129-130
Author(s):  
María-Fernanda Nieva
Keyword(s):  
Mass Range ◽  
Eclipsing Binaries ◽  
Precision Data ◽  
Hydrogen Burning ◽  
Fundamental Parameters ◽  
Accuracy And Precision ◽  
High Precision Data ◽  
Ob Associations ◽  
Better Than

AbstractFundamental parameters of 26 well-studied sharp-lined single early B-type stars in OB associations and in the field within a distance of ≤400 pc from the Sun are compared to high-precision data from detached eclipsing binaries (DEBs). Fundamental parameters are derived from accurate and precise atmospheric parameters determined earlier by us from non-LTE analyses of high-quality spectra, utilising the new Geneva stellar evolution models in the mass-range ~6 to 18 M⊙ at metallicity Z = 0.014. Evolutionary masses, radii and luminosities are determined to better than typically 5%, 10%, and 20% uncertainty, respectively, facilitating the mass-radius and mass-luminosity relationships to be recovered for single core hydrogen-burning objects with a similar precision as derived from DEBs. Good agreement between evolutionary and spectroscopic masses is found. Absolute visual and bolometric magnitudes are derived to typically ~0.15-0.20 mag uncertainty. Metallicities are constrained to better than 15-20% uncertainty and tight constraints on evolutionary ages of the stars are provided. The spectroscopic distances and ages of individual sample stars agree with independently derived values for the host OB associations. The accuracy and precision achieved in the determination of fundamental stellar parameters from the quantitative spectroscopy of single early B-type stars comes close (within a factor 2-4) to data derived from DEBs.

scholarly journals Rapid Gas Chromatographic Method for Simultaneous Determination of Cholesterol and α-Tocopherol in Eggs

1998 ◽  
Vol 81 (6) ◽  
pp. 1177-1184 ◽  
Author(s):  
Nickos Botsoglou ◽  
Dimitrios Fletouris ◽  
Ioannis Psomas ◽  
Antonios Mantis
Keyword(s):  
Simultaneous Determination ◽  
Chromatographic Method ◽  
Labor Cost ◽  
Precision Data ◽  
Total Analysis Time ◽  
Accuracy And Precision ◽  
Relative Standard ◽  
Total Analysis ◽  
Gas Chromatographic Method

Abstract A new method was developed for simultaneous determination of cholesterol and α-tocopherol in eggs. It involves rapid and simple sample preparation accomplished in one tube and chromatographic separation that does not require derivatization of analytes. Total analysis time per sample is 40 min. Labor, cost, and use of hazardous chemicals are minimized. To ensure selectivity, accuracy, and precision, critical analytical parameters were investigated. Overall recoveries were 98.8 and 99.2% for cholesterol and α-tocopherol, respectively. Linearity was acceptable for both analytes (r = 0.9964 for cholesterol and 0.9996 for α-tocopherol) in the fortification range examined. Precision data based on within-day and between-days variation gave overall relative standard deviations of 2.0% for cholesterol and 7.0% for α-tocopherol.The method was applied successfully for quantitation of cholesterol and α-tocopherol in eggs.

Development and Single-Laboratory Validation of an Improved Method for the Determination of Cyclamate in Foods Using Liquid Chromatography/Tandem Mass Spectrometry

2014 ◽  
Vol 97 (6) ◽  
pp. 1651-1655 ◽  
Author(s):  
Romina Shah ◽  
Lowri S De Jager ◽  
Timothy H Begley
Keyword(s):  
Internal Standard ◽  
Pomegranate Juice ◽  
Spectral Determination ◽  
Precision Data ◽  
Mass Spectral ◽  
Minimal Sample ◽  
Accuracy And Precision ◽  
Liquid Chromatography Tandem Mass ◽  
Potential Matrix

Abstract A fast and reliable LC-MS/MS method for the determination of cyclamate in a variety of food matrices was developed and validated. This method provides both quantitation and qualitative mass spectral determination important for analysis of regulatory samples. Utilization of a cyclamate-d11 internal standard corrects for potential matrix interferences during sample injection and allows minimal sample preparation. Seventeen commercially available food products were fortified at 250 μg/mL and tested as part of the method validation. Recoveries ranged from 72 to 110%, with RSDs ranging from 3 to 15%. The linear range spanned 0.010–1.00 μg/mL. LODs were 0.1 and 0.6 ng/mL, determined in pomegranate juice and dried fig, respectively. LOQs were 0.3 and 1.6 ng/mL, which are significantly lower than needed to measure cyclamate when used as a food additive. The interday and intraday accuracy and precision data are presented. This method was validated for analysis of a variety of commonly adulterated products, including drinks, dried fruits, jams, and hard candies.

scholarly journals Updated astrometry and masses of the LUH 16 brown dwarf binary

2018 ◽  
Vol 618 ◽  
pp. A111 ◽  
Author(s):  
P. F. Lazorenko ◽  
J. Sahlmann
Keyword(s):  
High Precision ◽  
Photographic Plate ◽  
Brown Dwarf ◽  
Precision Data ◽  
Orbital Parameters ◽  
Very Large Telescope ◽  
High Precision Data ◽  
The Absolute ◽  
The Individual

The nearest known binary brown dwarf WISE J104915.57–531906.1AB (LUH 16) is a well-studied benchmark for our understanding of substellar objects. Previously published astrometry of LUH 16 obtained with FORS2 on the Very Large Telescope was affected by errors that limited its use in combination with other datasets, thereby hampering the determination of its accurate orbital parameters and masses. We improve upon the calibration and analysis of the FORS2 astrometry with the help of Gaia DR2 to generate a high-precision dataset that can be combined with present and future LUH 16 astrometry. We demonstrate its use by combining it with available measurements from the Hubble Space Telescope (HST) and Gemini/GeMS and deriving updated orbital and mass parameters. Using Gaia DR2 as astrometric reference field, we derived the absolute proper motion and updated the absolute parallax of the binary to 501.557 ± 0.082 mas. We refined the individual dynamical masses of LUH 16 to 33.5 ± 0.3 M Jup (component A) and 28.6 ± 0.3 M Jup (component B), which corresponds to a relative precision of ∼1% and is three to four times more precise than previous estimates. We found that these masses show a weak dependence on one datapoint extracted from a photographic plate from 1984. The exact determination of a residual mass bias, if any, will be possible when more high-precision data can be incorporated in the analysis.

scholarly journals Absolute Parameter Determination in Low-Mass Eclipsing Binaries. Radiative Parameters for BH VIR, ZZ UMa and CR Cas

1993 ◽  
Vol 137 ◽  
pp. 386-391
Author(s):  
R. Clement ◽  
V. Reglero ◽  
M. Garcia ◽  
J. Fabregat ◽  
A. Bravo ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Monitoring Program ◽  
Mass Range ◽  
Eclipsing Binaries ◽  
Radiative Properties ◽  
Parameter Determination ◽  
Low Mass ◽  
Observational Program

AbstractA new uvby and Hβ monitoring program of low mass eclipsing binaries is currently being carried out in the framework of a 5 year observational program which also involves radial velocity determinations. The scope of this work is to provide very accurate absolute astrophysical parameters: mass, radius and effective temperatures, for main sequence late-type stars. One of the main goals is to improve the mass-luminosity relation in the low and intermediate mass range. A second objective is to perform accurate tests of the most recent grids of evolutionary models. This program is complementary to that currently being in progresss by the Copenhagen group.In this contribution we present the photometric preliminary results obtained for three of the systems included in our long term survey: BH Vir, ZZ UMa and CR Cas for which, primary eclipses have been observed. Particular attention is paid to the determination of reddening, distances and radiative properties. A more detailed study will be carried out when the light curves and radial velocity measurements are completed

scholarly journals CM Draconis: Masses and Radii of Very Low Mass Stars

2006 ◽  
Vol 2 (S240) ◽  
pp. 628-630
Author(s):  
J.C. Morales ◽  
I. Ribas ◽  
C. Jordi ◽  
G. Torres ◽  
E.F. Guinan ◽  
...  
Keyword(s):  
Magnetic Activity ◽  
Time Span ◽  
Eclipsing Binaries ◽  
Light Curves ◽  
Low Mass Stars ◽  
Fundamental Properties ◽  
Low Mass ◽  
Effective Temperatures ◽  
Better Than

AbstractIn this work we have studied CM Draconis, one of the least massive eclipsing binaries known. Its components are very similar, with masses and radii of about 0.23 M⊙ and 0.25 R⊙. We have analysed light curves in the R and I bands to calculate the fundamental properties of this system with accuracies better than 1%. With these results we plan to carry out a thorough test of the models, which have been found to predict smaller radii and larger effective temperatures than observed for these low-mass stars. This will also be especially interesting in the case of CM Dra since the mechanism driving magnetic activity is thought to be different from that of more massive stars. In addition, the extended time-span of the observations has led to the detection of apsidal motion. This provides a further check on models through the determination of the internal structure of the stars.

Collaborative Study of Accuracy and Precision of Rapid Determination of Fat in Meat and Meat Products by Foss-Let Method

1977 ◽  
Vol 60 (4) ◽  
pp. 853-858 ◽  
Author(s):  
Julio D Pettinati ◽  
Clifton E Swift
Keyword(s):  
Food Industry ◽  
Rapid Determination ◽  
Collaborative Study ◽  
Meat Products ◽  
T Test ◽  
Laboratory Sample ◽  
Accuracy And Precision ◽  
Aoac Method ◽  
Better Than

Abstract Collaborators in 12 meat and food industry laboratories performed 4 fat determinations each on 7 samples of meat and meat products by the rapid (7–10 min) Foss-Let method and compared the results with those obtained by AOAC method 24.005(a) or 24.005(b). From the overall mean of results on all samples, determinations by the Foss-Let method averaged 0.11% fat higher than by the AOAC method. This difference was not significant by the t-test (P = 0.05), which indicated agreement between the compared methods in determining fat content. Precision of the Foss-Let method was equivalent to and generally slightly better than that of the AOAC method. Standard deviations with the Foss-Let method were 0.2 % fat for between-duplicates and for within-laboratory repeatability; 0.4% fat for between-laboratories, including variation due to laboratory-sample interaction; and 0.5% fat for reproducibility between analysts in different laboratories. The Foss-Let method has been adopted as official first action.

scholarly journals A Novel Approach for the Determination of the Height of the Tropopause from Ground-Based GNSS Observations

2020 ◽  
Vol 12 (2) ◽  
pp. 293 ◽  
Author(s):  
Jorge Mendez Astudillo ◽  
Lawrence Lau ◽  
Yu-Ting Tang ◽  
Terry Moore
Keyword(s):  
Refractive Index ◽  
Lapse Rate ◽  
Radiosonde Data ◽  
Precision Data ◽  
Novel Approach ◽  
Radio Signals ◽  
High Precision Data ◽  
Novel Method ◽  
Gnss Data

In this paper, we present a new method to calculate the height of the second lapse-rate tropopause (LRT2) using GNSS high-precision data. The use of GNSS data for monitoring the atmosphere is possible because as the radio signals propagate through the troposphere, they are delayed according to the refractive index of the path of the signal. We show that by integrating the vertical profile of the refractive index in the troposphere, we are able to determine the altitude of LTR2. Furthermore, as GNSS data is available from many stations around all latitudes of the globe and make up a network with high spatial and temporal resolution, we can monitor the diurnal cycle of the variables related to the refractive index of the path of the signal. A comparison between the heights of the LRT2 obtained with radiosonde data and with this novel method is presented in the paper, and it shows good agreement. The average difference found is ≤1 km for stations between the latitudes of 30°S and 30°N.

An Automated Method for the Determination of Serum Bilirubin

1964 ◽  
Vol 10 (5) ◽  
pp. 399-405 ◽  
Author(s):  
Murray Golub
Keyword(s):  
Chemical Analysis ◽  
Good Accuracy ◽  
Total Bilirubin ◽  
Serum Bilirubin ◽  
Diazonium Salt ◽  
Reference Method ◽  
Precision Data ◽  
Automated Method ◽  
Accuracy And Precision

Abstract The bilirubin method of Rand and DiPasqua (3), which utilizes a stabilized diazonium salt solution of 2,4 dichloraniline, has been adapted to automatic chemical analysis. Both total bilirubin and "1-min. reacting" bilirubin can be assayed with good accuracy and precision. Data are presented to show excellent agreement with the manually performed procedure and the procedure of Malloy and Evelyn (1), which was used as the reference method.

scholarly journals Continuous Flow Techniques for the Determination of Serum Calcium and the Simultaneous Determination of Calcium and Inorganic Phosphate in Serum and Urine

1974 ◽  
Vol 11 (1-6) ◽  
pp. 81-85
Author(s):  
W. G. Brydon
Keyword(s):  
Simultaneous Determination ◽  
Serum Calcium ◽  
Continuous Flow ◽  
Inorganic Phosphate ◽  
Methyl Green ◽  
Fluorometric Method ◽  
Precision Data ◽  
Accuracy And Precision ◽  
Serum And Urine

The fluorometric method of Fingerhut et al. (1969) for the determination of serum calcium has been modified to approximately treble the sensitivity. Using only 120 μl of sample a method has been developed for the simultaneous determination of calcium and inorganic phosphate in serum and urine, the phosphate being measured by complexing phosphomolybdate with methyl green, a method developed by Van Belle (1970). Only a single dialysis stage is required, and reagents and sample can be delivered using an AutoAnalyzer Pump I. The techniques correlate well with other methods. Accuracy and precision data are presented.

A Simple Method for Determination of the Elastic Modulus of Thin Films on a Substrate

1993 ◽  
Vol 308 ◽  
Author(s):  
M.V. Swain ◽  
E.R. Weppelmann
Keyword(s):  
Thin Films ◽  
High Precision ◽  
Elastic Contact ◽  
Precision Data ◽  
Simple Method ◽  
Tin Film ◽  
High Precision Data ◽  
Properties Of Materials ◽  
Force Displacement

ABSTRACTHigh precision force displacement indenting instruments are now widely used for the determination of the mechanical properties of materials. However, for thin films attached to a substrate, the basis of any analysis of such high precision data is still limited. In this study the force displacement data has been generated using spherically tipped indenters of radii from 5 to 150 μm loaded onto a 2.74 μm thick TiN film on a silicon substrate as well as onto the substrate directly. Data have been generated using two loading procedures, continuous and load partial-unloading, almost entirely within the elastic contact regime. The results are analysed to determine the modulus of the TiN film.

Sign in / Sign up

Export Citation Format

Share Document