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Wyszukujesz frazę "kinetics of degradation" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
The Applicability of Chromatographic Methods in the Investigation of Ageing Processes in Double Base Rocket Propellants
Autorzy:
Matečić-Muśanić, S.
Sućeska, M.
Čuljak, R.
Powiązania:
https://bibliotekanauki.pl/articles/358695.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
activation energy
artifcial ageing
DB rocket propellants
decomposition
Ethyl Centralite (EC)
Gel Permeation Chromatography (GPC)
High Performance Liquid Chromatography (HPLC)
kinetics of degradation
mean molecular mass of NC
Opis:
The ageing of double base (DB) rocket propellants is the result of chemical decomposition reactions and physical processes, causing degradation of a number of relevant propellant properties (such as reduction in stabilizer and nitroglycerine (NG) content, reduction of the mean molecular mass of nitrocellulose (NC) etc.), which is refected in a decrease in the reliable service life time of DB propellants. This is the reason why the study of processes of ageing and their consequences (effects) is so important. In this paper we have studied the kinetics of DB rocket propellant decomposition during their artifcial ageing, i.e. at elevated temperatures. The kinetic parameters were obtained by measurements of the stabilizer/Ethyl Centralite (EC) content and the mean molecular mass reduction of NC, during artifcial ageing at temperatures of 80, 85 and 90 °C. Consumption of the EC was observed using High Performance Liquid Chromatography (HPLC), whilst the reduction in the mean molecular mass of NC was monitored using Gel Permeation Chromatography (GPC). It has been shown that artifcial ageing of DB propellant causes signifcant EC consumption and a reduction in the mean molecular mass of NC, from the very beginning of ageing. EC is entirely consumed after 120 days at 80 °C, and is followed by the intensive reactions of NC decomposition. Signifcant changes in the mean molecular mass of NC starts after 60 days of ageing at 90 °C (or ~250 days at 80 °C). The results obtained from the kinetic data have shown that the activation energy of DB propellant decomposition, determined on the basis of changes in the mean molecular mass of NC is 145.09 kJ•mol-1 , whilst the activation energy of decomposition obtained on the basis of EC consumption is 142.98 kJ•mol-1 , which is consistent with available literature values [1, 2].
Źródło:
Central European Journal of Energetic Materials; 2013, 10, 2; 245-262
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kinetics of degradation of perchloroethylene under ultrasonic irradiation and photooxidation in aqueous solution
Autorzy:
Kargar, M.
Nabizadeh, R.
Naddafi, K.
Nasseri, S.
Mesdaghinia, A.
Mahvi, A. H.
Alimohammadi, M.
Nazmara, S.
Powiązania:
https://bibliotekanauki.pl/articles/206938.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
związki organiczne
chromatografia gazowa
napromieniowanie
fotooksydacja
chlorowane węglowodory alifatyczne
kinetyka degradacji
czterochlorek etylenu
czterochloroetylen
per
tetrachloroeten
perchloroetylen
sonoliza
napromieniowanie ultradźwiękowe
organic compounds
gas chromatography
irradiation
photooxidation
chlorinated aliphatic hydrocarbons
kinetics of degradation
perchloroethylene
tetrachloroethylene
PCE
sonolysis
ultrasound irradiation
Opis:
Sonolysis and photodegradation of various compounds such as chlorinated aliphatic hydrocarbons are the recent advanced oxidation processes. Perchloroethylene PCE is one of these compounds mainly used as a solvent and degreaser. In this work, elimination of perchloroethylene in aqueous solution by ultrasonic irradiation and photooxidation by UVC were investigated. Head space gas chromatography with FID detector was used for analyses of PCE. Results showed that PCE could be effectively and rapidly degraded by ultrasonic irradiation, photooxidation by UVC and combination of these methods. The order of studied reactions for degradation PCE has been determined.
Źródło:
Environment Protection Engineering; 2013, 39, 4; 29-38
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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