Triple Oxygen Isotope Analysis of Nitrate Using the Denitrifier Method and Thermal Decomposition of N2O

2007 ◽  
Vol 79 (2) ◽  
pp. 599-607 ◽  
Author(s):  
Jan Kaiser ◽  
Meredith G. Hastings ◽  
Benjamin Z. Houlton ◽  
Thomas Röckmann ◽  
Daniel M. Sigman
Keyword(s):  
Thermal Decomposition ◽  
Oxygen Isotope ◽  
Isotope Analysis ◽  
Denitrifier Method

Revisiting apatite SIMS oxygen isotope analysis and qinghu reference material

2021 ◽  
pp. 120445
Author(s):  
Yang Li ◽  
Guo-Qiang Tang ◽  
Yu Liu ◽  
Sheng He ◽  
Bo Chen ◽  
...  
Keyword(s):  
Reference Material ◽  
Oxygen Isotope ◽  
Isotope Analysis

scholarly journals New Ag 3 PO 4 comparison material for stable oxygen isotope analysis

2021 ◽  
Author(s):  
Andrea Watzinger ◽  
Katharina Schott ◽  
Rebecca Hood‐Nowotny ◽  
Federica Tamburini ◽  
Laura Arppe ◽  
...  
Keyword(s):  
Oxygen Isotope ◽  
Isotope Analysis ◽  
Stable Oxygen Isotope ◽  
Stable Oxygen

Cleaning of lake sediment samples for diatom oxygen isotope analysis

2004 ◽  
Vol 31 (3) ◽  
pp. 391-401 ◽  
Author(s):  
David W. Morley ◽  
Melanie J. Leng ◽  
Anson W. Mackay ◽  
Hilary J. Sloane ◽  
Patrick Rioual ◽  
...  
Keyword(s):  
Oxygen Isotope ◽  
Lake Sediment ◽  
Isotope Analysis ◽  
Sediment Samples

Sensitization of nitrocompounds by amines

1992 ◽  
Vol 339 (1654) ◽  
pp. 403-417 ◽  
Keyword(s):  
Thermal Decomposition ◽  
Charge Transfer ◽  
Nitro Group ◽  
Picric Acid ◽  
Isotope Analysis ◽  
Ionization Mass ◽  
Scanning Calorimetry ◽  
Absorption Bands ◽  
Rate Determining Step ◽  
The Impact

A study has been carried out of the sensitization of nitromethane, trinitrotoluene, trinitrobenzene, picric acid and tetryl by the addition of small amounts of amines. The sensitization has been confirmed using dropweight impact experiments and a new method has been found, using differential scanning calorimetry, of making reproducible and quantitative measurements of the effect. It is found that the nitrocompound-amine mixtures decompose at temperatures lower than those of either of the pure components and show a drop in the impact energy required to cause initiation of ignition. The thermal decomposition experiments also yield substantially lower activation energies and an empirical sensitization factor (defined in the text) for nitromethane mixtures that decreases as the nitromethane aci-anion concentration increases. Kinetic deuterium isotope analysis points to C-N bond scission as the rate-determining step in the thermal decomposition of nitromethane and nitromethane-amine mixtures. Laser ionization mass analyses of the solid nitrocompound-amine mixtures indicate significant changes in the fragmentation patterns, with removal of the nitro-group occurring in all cases as the first step in the breakdown of the mixtures, which is not the case for the pure materials. Absorption bands appear in the UV / visible spectra of all the sensitized materials. These bands are ascribed to an intermolecular charge transfer from the nitrogen of an amine group to the antibonding orbital of the nitro-group. It is shown that, with small amounts of amines present, each amine molecule can form a complex with as many nitrocompound molecules as there are amine groups on it. The formation of this charge transfer complex is shown to weaken the nitrocompound C-N bond involved. The weakening of the C-N bond increases directly with increasing binding energy of the complex. Combined with the knowledge that the C-N bond breakage is the rate- ­determining step in the thermal decomposition of these materials and the suggestion that the dominant mechanism in their ignition/detonation is most likely thermal in origin, the sensitization is explained. This explanation deviates from the theories which have been previously proposed.

scholarly journals Sampling and Pretreatment of Tooth Enamel Carbonate for Stable Carbon and Oxygen Isotope Analysis

10.3791/58002 ◽  
2018 ◽  
Author(s):  
Alicia Ventresca Miller ◽  
Ricardo Fernandes ◽  
Anneke Janzen ◽  
Ayushi Nayak ◽  
Jillian Swift ◽  
...  
Keyword(s):  
Oxygen Isotope ◽  
Tooth Enamel ◽  
Isotope Analysis ◽  
Stable Carbon ◽  
Carbon And Oxygen Isotope
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