Search Results

You are looking at 11 - 20 of 32 items for :

  • "nitric oxide" x
  • Chemistry and Chemical Engineering x
  • All content x
Clear All

Abstract  

The hyphenated thermal analysis-mass spectrometry technique (TA-MS) was applied for the investigation of the thermal behavior of reference and aged parchment samples. The kinetic parameters of the process were calculated independently from all recorded TA and MS signals. The kinetic analysis showed the distinct dependence of the activation energy on the reaction progress. Such behavior is characteristic for the multistage mechanism of the reaction. The comparison of the kinetic parameters calculated from the different signals i.e. TG, DSC, MS for H2O, NO and CO2, however, indicated that they were differently dependent on the aging of the sample. For the parchment samples, the aging almost does not change the kinetics of the decomposition calculated from the DSC data: the influence of aging seems to be too negligible to be detected by these techniques. On the other hand, the much more sensitive mass spectrometric technique applied to the kinetic analysis allowed monitoring of visible changes in the thermal behavior of the parchment samples due to the aging process. The influence of aging was especially visible when the MS signals of water and nitric oxide were applied for the determination of the kinetic parameters. The applied method of the kinetic analysis allowed also the prediction of the thermal behaviour of reference and aged parchment samples under isothermal and modulated temperature conditions. Presented results have confirmed the usefulness of thermoanalytical methods for investigating behaviour of such complicated systems as leather or parchment.

Restricted access

Thermal decomposition of uranyl nitrate hexahydrate

A thermal analysis—mass spectrometry study

Journal of Thermal Analysis and Calorimetry
Authors: K. Rajagopalan, P. Ravindran, and T. Radhakrishnan

Abstract  

TG-DTA-EGA studies have shown that anhydrous uranyl nitrate cannot be obtained by thermal decomposition of uranyl nitrate hexahydrate. Hydrolysis and polymerization of the salt during dehydration resulted in hydroxynitrates which decomposed in multiple steps with the evolution of oxides of nitrogen and water. The extent of hydrolysis dependend on the sample size, heating rate and nature of sample containment. Large samples on decomposition at relatively high heating rates showed evolution of nitric oxide even above 500°C. Infrared studies on the residues prepared at various temperatures supported the conclusions.

Restricted access

1695 1700 P. Lorenz, S. Roychowdhury, M. Engelmann, G. Wolf, T.F.W. Horn , Nitric Oxide 9 (2003) 64–76. Horn T

Restricted access

. [7] M. Nakashima , Y. Shigekuni , T. Obi , M. Shiraishi , A. Miyamoto , H. Yamasaki , T. Etoh , S. Iwai , Nitric oxide-dependent hypotensive effects of wax gourd

Restricted access
Agrokémia és Talajtan
Authors: György Heltai, Attila Anton, Sándor Hoffmann, Tibor Szili-Kovács, Katalin Berecz, Györgyi Kampfl, Krisztina Kristóf, Erik Molnár, Márk Horváth, and Ágnes Bálint

609 640 Davidson, E. A. & Kingerlee, W. , 1997. Global inventory of emissions of nitric oxide from soils: A literature review. Nutrient Cycling in Agroecosystems

Restricted access
Agrokémia és Talajtan
Authors: Szandra Baklanov, Ágota Horel, Györgyi Gelybó, Eszter Tóth, Márton Dencső, Emese Ujj, and Imre Potyó

. Paul , J.W. , Beauchamp , E.G. & Zhang , X. 1993 . Nitrous and nitric oxide emissions during nitrification and denitrification from manure-amended soil in the laboratory . Canadian Journal of Soil Science . 73 . 539

Open access
Journal of Thermal Analysis and Calorimetry
Authors: Daniele Bergamasco, Franco Bulian, Andrea Melchior, Davide Menotti, Paolo Tirelli, and Marilena Tolazzi

materials 2005 William Andrew Norwich . 10. Hon , DNS , Feist , WC . Interaction of sulfur dioxide and nitric oxide with photoirradiated wood surfaces

Restricted access

dehydrogenation of propane . J Catal . 224 : 417 – 428 10.1016/j.jcat.2004.03.010 . 26. Li , Y , Huang , Z , Rong , S . 2006 . A vanadium oxide nanotube-based nitric oxide gas sensor . Sens

Restricted access

phytoestrogens: Transcriptional regulation of nitric oxide synthase and antioxidant defense genes . Free Radical Biology & Medicine . 42 . 909 – 925 . S ohár , P.-né. , M atyosovszky , K

Open access

oxygen/carbon dioxide atmosphere and nitric oxide release during this process . Energy Convers Manag . 2011 ; 52 : 532 – 537 . 10.1016/j.enconman.2010.07.028 . 22. Miao , ZY , Wu , GG

Restricted access