Results 201 to 210 of about 9,719 (242)

Simultaneous Determination of Stable Carbon, Oxygen, and Hydrogen Isotopes in Cellulose

Analytical Chemistry, 2014
A technological development is described through which the stable carbon-, oxygen-, and nonexchangeable hydrogen-isotopic ratios (δ(13)C, δ(18)O, δ(2)H) are determined on a single carbohydrate (cellulose) sample with precision equivalent to conventional techniques (δ(13)C 0.15‰, δ(18)O 0.30‰, δ(2)H 3.0‰). This triple-isotope approach offers significant
Loader N. J., Street-Perrott F. A., Daley T. J., Hughes P. D. M., Kimak A., Levanic T., Mallon G., Mauquoy D., Robertson I., Roland T. P., van Bellen S., Ziehmer M. M., Leuenberger M.   +12 more
openaire   +5 more sources

Stable hydrogen and oxygen isotope ratios of bottled waters of the world

Rapid Communications in Mass Spectrometry, 2005
Abstract Bottled and packaged waters are an increasingly significant component of the human diet. These products are regulated at the regional, national, and international levels, and determining the authenticity of marketing and labeling claims represents a challenge to regulatory agencies.
Gabriel J, Bowen, David A, Winter, Howard J, Spero, Robert A, Zierenberg, Mathew D, Reeder, Thure E, Cerling, James R, Ehleringer   +6 more
openaire   +2 more sources

Global application of stable hydrogen and oxygen isotopes to wildlife forensics

Oecologia, 2005
Stable isotopes are being increasingly used in wildlife forensics as means of determining the origin and movement of animals. The heavy isotope content of precipitated water and snow (deltaD(p), delta(18)O(p)) varies widely and systematically across the globe, providing a label that is incorporated through diet into animal tissue.
Gabriel J, Bowen, Leonard I, Wassenaar, Keith A, Hobson   +2 more
openaire   +2 more sources

Hydrogen Burning of the Rare Oxygen Isotopes

2014
At the Laboratory for Experimental Nuclear Astrophysics (LENA), two rare oxygen isotope proton capture studies were performed at low energies---18O(p,γ)19F and 17O(p,γ)18F. The goal of each study was to improve thermonuclear reaction rates at stellar plasma temperatures relevant to 18O and 17O destruction, respectively.
openaire   +1 more source

Hydrogen and Oxygen Stable Isotope Ratios of Milk in the United States

Journal of Agricultural and Food Chemistry, 2010
Models of hydrogen and oxygen incorporation in human tissues recognize the impact of geographic location on the isotopic composition of fluid intake, but inputs can include nonlocal beverages, such as milk. Milk and cow drinking water were collected from dairies, and commercially available milk was purchased from supermarkets and fast food restaurants.
Lesley A, Chesson, Luciano O, Valenzuela, Shannon P, O'Grady, Thure E, Cerling, James R, Ehleringer   +4 more
openaire   +2 more sources

Antiphase hydrogen and oxygen isotope periodicity in chert nodules

Geochimica et Cosmochimica Acta, 2002
Abstract Oxygen and hydrogen isotope analyses were made of Jurassic-age chert nodules from the Holy Cross Mountains, SE Poland, along radial transects at high spatial resolution. There is a radial “sigmoidal” periodicity for both isotope ratios, but the two are out of phase, with high δD values corresponding to low δ 18 O values.
Zachary D. Sharp, Tomasz Durakiewicz, Zdzislaw M. Migaszewski, Viorel N. Atudorei   +3 more
openaire   +1 more source

Study on the Variation of Hydrogen and Oxygen Isotopes in Soil Water

2008 2nd International Conference on Bioinformatics and Biomedical Engineering, 2008
Understanding the movement of soil water is important for water resource management and for analyzing pollutant transport in the vadose zone. The information about transfer and transformation in soil water could be provided by isotope tracing technology. The stable isotopic composition of soil water may be affected by many factors, e.g.
Haiying Hu, Weimin Bao, Tao Wang, Simin Qu   +3 more
openaire   +1 more source

Oxygen and Hydrogen Stable Isotopes in Earth’s Hydrologic Cycle

2016
Today’s geochemistry would be hard to imagine without stable isotope research that enabled the investigation of many fundamental geoscientific questions. Stable isotopes play an important role in water research and proved to be essential for understanding basic hydrological processes including groundwater recharge, origin of precipitation, and runoff ...
Robert van Geldern, Johannes A. C. Barth
openaire   +1 more source

Distribution of Heavy Hydrogen and Oxygen Isotopes in Water Distillation

Theoretical Foundations of Chemical Engineering, 2019
The possibility of high-precision determination of mass transfer characteristics of stainless steel packings in the separation of hydrogen and oxygen isotopes by vacuum distillation of water in columns with a diameter of 60–250 mm was shown. An algorithm for calculating the parameters of separation and the concentration profile of deuterium and oxygen ...
E. P. Magomedbekov, I. L. Rastunova, I. L. Selivanenko, N. N. Kulov   +3 more
openaire   +1 more source

Hydrogen, oxygen and silicon isotope systematics in lunar material

Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences, 1977
Abstract In this review the following conclusions are supported: (1) The bulk of the hydrogen in the lunar soils represents protons implanted from the solar wind and is essentially deuterium free. (2) Rarely samples of relatively detuerium rich hydrogen are found, probably resulting from in situ spallation reactions.
openaire   +1 more source