scholarly journals Temporal variations of the carbon isotopic ratio of atmospheric methane observed at Ny Ålesund, Svalbard from 1996 to 2004

2006 ◽  
Vol 33 (1) ◽  
pp. n/a-n/a ◽  
Author(s):  
Shinji Morimoto ◽  
Shuji Aoki ◽  
Takakiyo Nakazawa ◽  
Takashi Yamanouchi
Keyword(s):  
Isotopic Ratio ◽  
Temporal Variations ◽  
Atmospheric Methane ◽  
Carbon Isotopic Ratio ◽  
Carbon Isotopic

Aircraft measurements of the stable carbon isotopic ratio of atmospheric methane over Siberia

1996 ◽  
Vol 10 (2) ◽  
pp. 223-231 ◽  
Author(s):  
Satoshi Sugawara ◽  
Takakiyo Nakazawa ◽  
Gen Inoue ◽  
Toshinobu Machida ◽  
Hitoshi Mukai ◽  
...  
Keyword(s):  
Isotopic Ratio ◽  
Aircraft Measurements ◽  
Atmospheric Methane ◽  
Stable Carbon ◽  
Carbon Isotopic Ratio ◽  
Carbon Isotopic

Detection of Adulterated Natural Sweeteners by Carbon Isotopic Ratio Analysis

2021 ◽  
Vol 36 (2) ◽  
pp. 148-153
Author(s):  
Hee-jin Choi ◽  
Jae-kyoo Lee ◽  
Ae-kyung Kim ◽  
Bo-kyeng Jung ◽  
Yun-jeong Yi ◽  
...  
Keyword(s):  
Isotopic Ratio ◽  
Ratio Analysis ◽  
Carbon Isotopic Ratio ◽  
Carbon Isotopic

scholarly journals Isotopic Ratios in Comets

1991 ◽  
Vol 116 (2) ◽  
pp. 879-895 ◽  
Author(s):  
V. Vanysek
Keyword(s):  
Isotopic Ratio ◽  
Chemical Fractionation ◽  
Interstellar Clouds ◽  
Outer Planets ◽  
Carbon Isotopic Ratio ◽  
Carbon Isotopic ◽  
Nuclear Species ◽  
Carbon Reservoir ◽  
Protosolar Nebula ◽  
The Individual

Abstract.The isotopic abundances depend on the universal evolution of elements and on the individual history of particular objects. Since it is believed that unprocessed material of the solar nebula is preserved in comets, the data concerning the abundance of stable isotopes in these primitive bodies are of some importance in the cosmological context. The present status of this problem is reviewed. The reliability of results for nuclear species with cosmological and cosmogonical implications, such as D/H, C 12/13, N 14/15, O 16/18, and Mg 24/25/26, is discussed. Significant variation is found for the isotopic abundance of carbon, depending upon which carbon reservoir is sampled. Deuterium is probably enhanced relative to the interstellar ratio. For other isotopes, the ratios are close to those of the terrestrial data. The tendency of the D/H ratio to be at higher values indicates a low temperature in the environment of the comet’s formation, and, together with similar effects in the outer planets, suggests that there were two different primordial reservoirs of deuterium in the solar system. The 12C/13C ratio inferred from in situ mass spectrometry of the dust, as well as from the ground-based optical spectra of the Swan band, tends to be approximately equal to the average terrestrial ratio (89) or larger. Recent results obtained from the CN band provide a significantly lower value (about 65), which corresponds to the carbon isotopic ratio in the diffuse interstellar clouds. The enhancement of deuterium and the possible differences of the carbon isotopic ratio in different species and refractory material are indicative of chemical fractionation processes in the protosolar nebula.

Determination of Fatty Acids and Stable Carbon Isotopic Ratio in Subcutaneous Fat to Identify the Feeding Regime of Iberian Pigs

2015 ◽  
Vol 63 (2) ◽  
pp. 692-699 ◽  
Author(s):  
María Asunción López-Bascón ◽  
Feliciano Priego-Capote ◽  
Mónica Calderón-Santiago ◽  
Verónica Sánchez de Medina ◽  
José Manuel Moreno-Rojas ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Isotopic Ratio ◽  
Subcutaneous Fat ◽  
Stable Carbon ◽  
Feeding Regime ◽  
Carbon Isotopic Ratio ◽  
Carbon Isotopic

scholarly journals Super lithium-rich K giant with low 12C to 13C ratio

2018 ◽  
Vol 615 ◽  
pp. A74 ◽  
Author(s):  
Y. T. Zhou ◽  
J. R. Shi ◽  
H. L. Yan ◽  
Q. Gao ◽  
J. B. Zhang ◽  
...  
Keyword(s):  
Luminosity Function ◽  
Isotopic Ratio ◽  
Rotational Velocity ◽  
Equilibrium Analysis ◽  
Evolutionary Status ◽  
Evolutionary Stage ◽  
Low Carbon ◽  
Great Opportunity ◽  
Carbon Isotopic Ratio ◽  
Carbon Isotopic

Context. The lithium abundances in a few percent of giants exceed the value predicted by the standard stellar evolution models, and the mechanisms of Li enhancement are still under debate. The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) survey has obtained over six million spectra in the past five years, and thus provides a great opportunity to search these rare objects and to more clearly understand the mechanisms of Li enhancement. Aims. The aim of this work is to accurately measure the Li abundance and investigate the possible mechanisms of Li enrichment for a newly found super Li-rich giant, TYC 3251-581-1, located near the luminosity function bump with a low carbon isotopic ratio. Methods. Based on the high-resolution spectrum we obtained the stellar parameters (Teff, logg, [Fe/H]), and determined the elemental abundances of Li, C, N, α, Fe-peak, r-process, s-process elements, and the projected rotational velocity. For a better understanding of the effect of mixing processes, we also derived the 12C to 13C ratio, and constrained the evolutionary status of TYC 3251-581-1 based on the BaSTI stellar isochrones. Results. The super Li-rich giant TYC 3251-581-1 has A(Li) = 3.51, the average abundance of two lithium lines at λ = 6708 Å and 6104 Å based on the non-local thermodynamic equilibrium analysis. The atmospheric parameters show that our target locates on the luminosity function bump. The low carbon isotopic ratio (12C∕13C = 9.0), a slow rotational velocity vsini = 2.2 km s−1, and no sign of IR excess suggest that additional mixing after first dredge up (FDU) should occur to bring internal synthesized Li to the surface. The low carbon ([C∕Fe] ~−0.34) and enhanced nitrogen ([N∕Fe] ~ 0.33) are also consistent with the sign of mixing. Conclusions. Given the evolutionary stage of TYC 3251-581-1 with the relatively low 12C∕13C, the internal production which replenishes Li in the outer layer is the most likely origin of Li enhancement for this star.

scholarly journals Combining Geoelectrical Measurements and CO2Analyses to Monitor the Enhanced Bioremediation of Hydrocarbon-Contaminated Soils: A Field Implementation

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Cécile Noel ◽  
Jean-Christophe Gourry ◽  
Jacques Deparis ◽  
Michaela Blessing ◽  
Ioannis Ignatiadis ◽  
...  
Keyword(s):  
Contaminated Soils ◽  
Isotopic Ratio ◽  
Geophysical Methods ◽  
Isotopic Signature ◽  
Geophysical Monitoring ◽  
Carbon Isotopic Ratio ◽  
Carbon Isotopic ◽  
Enhanced Biodegradation ◽  
Enhanced Bioremediation

Hydrocarbon-contaminated aquifers can be successfully remediated through enhanced biodegradation. However,in situmonitoring of the treatment by piezometers is expensive and invasive and might be insufficient as the information provided is restricted to vertical profiles at discrete locations. An alternative method was tested in order to improve the robustness of the monitoring. Geophysical methods, electrical resistivity (ER) and induced polarization (IP), were combined with gas analyses, CO2concentration, and its carbon isotopic ratio, to develop a less invasive methodology for monitoring enhanced biodegradation of hydrocarbons. The field implementation of this monitoring methodology, which lasted from February 2014 until June 2015, was carried out at a BTEX-polluted site under aerobic biotreatment. Geophysical monitoring shows a more conductive and chargeable area which corresponds to the contaminated zone. In this area, high CO2emissions have been measured with an isotopic signature demonstrating that the main source of CO2on this site is the biodegradation of hydrocarbon fuels. Besides, the evolution of geochemical and geophysical data over a year seems to show the seasonal variation of bacterial activity. Combining geophysics with gas analyses is thus promising to provide a new methodology forin situmonitoring.

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