Search Results
Abstract
Thermogravimetric analysis (TG) was used in this work to study the degradation kinetics of industrial PVC plastisols. In order to model the pyrolitic degradation of plastisols in nitrogen, a kinetic model based on phenomenological considerations was developed. Two different processes were observed during the first degradation stage. The model parameters, such as activation energies and pseudo orders of reaction, were calculated using a non-linear regression analysis. The model developed was able to describe the degradation behaviour both in isothermal and in dynamic modes. The results of such analysis were applied to obtain long-term data from short-term experiments as an engineering approach to evaluate the thermal resistance of plastisols.
A simplified kinetic model for isothermal catalytic ignition
Propane/air mixture on platinum wire
temperatures, for the stoichiometric propane/air mixture occurring in isothermal conditions on platinum wire. The results are rationalized on the basis of a simple kinetic model implying the multiplication of the surface active intermediates and resulting in a
of non-isothermal and isothermal kinetic models simulations led to a beneficial kinetic model of thermal decomposition to predict the thermal hazard of LOPs. The chosen approach was to establish an effective model of the thermal decomposition that
types of active sites on the catalyst surface permits effective kinetic modeling for a given set of operating conditions. Olefin polymerization kinetics has been investigated for a wide variety of polymerization systems, but in most cases, the
also more subject to steric hindrance compared with water [ 28 ]. These effects resulted in the optimum amount of water being higher than that for methanol. Conclusions A kinetic model describing PDH and catalyst deactivation
temperature than iron-based catalysts [ 7 ]. Co-based FTS is further favored since the reaction is little affected by water [ 8 – 10 ]. The development of a kinetic model of FTS is important for the simulation, design, and optimization of commercial FT
Abstract
The kinetic of the reaction ilmenite with sulphuric acid was studied using non-adiabatic and non-isothermic calorimetric device system. The kinetic model based on interphase surface and kinetic models found in literature which are usually applied were tested. The best agreement between experimental and calculated values was found with model based on first order of reaction and model of contracting volume.
Abstract
The non-isothermal data given by TG curves for poly(3-hydroxybutyrate) (PHB) were studied in order to obtain a consistent kinetic model that better represents the PHB thermal decomposition. Thus, data obtained from the dynamic TG curves were suitably managed in order to obtain the Arrhenius kinetic parameter E according to the isoconversional F-W-O method. Once the E parameters is found, a suitable logA and kinetic model (f(α)) could be calculated. Hence, the kinetic triplet (E±SD, logA±SD and f(α)) obtained for the thermal decomposition of PHB under non-isothermal conditions was E=152±4 kJ mol−1, logA=14.1±0.2 s−1 for the kinetic model, and the autocatalytic model function was: f(α)=αm(1−α)n=α0.42(1−α)0.56.
Abstract
Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) is a typical highly energetic material that has been widely used in national defense industries since the 1940s. The aim of this study was to establish a reaction kinetic model on thermal decomposition properties via differential scanning calorimetry (DSC) by well-known kinetic equations and kinetic model simulation. Furthermore, the aim also was to compare kinetic algorithms for thermal decomposition energy parameters under various conditions. Experimental results highly depended on the reliability of the kinetic concept applied, which is essentially defined by the proper choice of a mathematical model of a reaction. In addition, the correctness of the methods is used for kinetics evaluation.
Abstract
Toughened glass panels used as a glazing material in multistorey buildings are known to fracture prematurely when they contain nickel sulfide inclusions as a result of the α-β phase recrystallisation in nickel sulfide. The kinetics of this recrystallisation were studied by differential scanning calorimetry (DSC) under isothermal and non-isothermal conditions. The recrystallisation was observed to be a two-step process with an induction period followed by the phase change. A two-stage kinetic model was used to estimate the recrystallisation time under ambient conditions. These values were found to correlate well with the observed time to failure for glass panels installed in multistorey buildings.
