Continuous monitoring of shelf lives of materials by application of data loggers with implemented kinetic parameters

The evaluation of the shelf life of, for example, food, pharmaceutical materials, polymers, and energetic materials at room or daily climate fluctuation temperatures requires kinetic analysis in temperature ranges which are as similar as possible to those at which the products will be stored or transported in. A comparison of the results of the evaluation of the shelf life of a propellant and a vaccine calculated by advanced kinetics and simplified 0th and 1st order kinetic models is presented. The obtained simulations show that the application of simplified kinetics or the commonly used mean kinetic temperature approach may result in an imprecise estimation of the shelf life. The implementation of the kinetic parameters obtained fromadvanced kinetic analyses into programmable data loggers allows the continuous online evaluation and display on a smartphone of the current extent of the deterioration of materials. The proposed approach is universal and can be used for any goods, any methods of shelf life determination, and any type of data loggers. Presented in this study, the continuous evaluation of the shelf life of perishable goods based on the Internet of Things (IoT) paradigm helps in the optimal storage/shipment and results in a significant decrease of waste

Prediction of thermal stability of materials by modified kinetic and model selection approaches based on limited amount of experimental points

The experimental data collected in the discontinuous mode are often used for the computation of reaction kinetics and, further, for the simulation of the thermal stability of materials. However, the kinetic calculations based on limited amount of sparse points require specific criteria allowing correct choice of the best kinetic model. We present the modified kinetic computations allowing considering one, two or even more reaction stages by applying unlimited amount of combinations of different kinetic models for the best description of the reaction course. The kinetic parameters are calculated using the truncated Šesták-Berggren (SB) approach and further verified by using the Akaike and Bayesian information criteria (AIC and BIC, respectively). The proposed method of kinetic and model selection for elaboration of sparse points were checked by the simulation of generated points with known, arbitrarily chosen kinetic parameters containing some scatter. The verified procedure was applied for the prediction of the thermal stability of energetic (propellant) and biological (vaccine) materials characterized by approximately 30 experimental data points

New kinetic approach for evaluation of hazard indicators based on merging DSC and ARC or large scale tests

The present study describes two methods of evaluation of hazard indicators such as Self Accelerating Decomposition Temperature (SADT) or Time to Maximum Rate under adiabatic conditions (TMRad) from the results of the experiments performed in mg scale by Differential Scanning Calorimetry (DSC). We discuss here: (i) the kinetic workflow in which the kinetic parameters of the investigated reaction evaluated from the DSC are used with the heat balance of the system and (ii) a novel merging approach in which DSC data are simultaneously considered with the results of other, temperature recorded experiments as e.g. Accelerating Rate Calorimetry (ARC), large scale experiments as e.g. cookoff, Dewar or SADT determination according to STANAG 4383 and UN regulations (Tests H.4 and H.1), respectively. The commonly kinetic-based approach is discussed and its results confirmed by those obtained in common project with Federal Institute for Materials Research and Testing, Berlin, Germany (BAM) in which the SADT for AIBN was investigated. The novel merging approach is illustrated by the results of the linked DSC-UN test H.1 data and DSC-ARC results applied for SADT determination and for evaluation of TMRad for any starting temperature for AIBN

Determination of thermal hazard from DSC measurements. Investigation of self-accelerating decomposition temperature (SADT) of AIBN

The method of determination of the thermal hazard properties of reactive chemicals from DSC experiments is illustrated by the results of SADT simulations performed with azobisisobutyronitrile (AIBN). The kinetics of decomposition of AIBN in the solid state was investigated in a narrow temperature window of 72–94 °C, just below the sample melting. The kinetic parameters of the decomposition were evaluated by differential isoconversional method. The very good fit of the experimental results by the simulation curves, based on the determined kinetic parameters, indicated the correctness of the kinetic description of the process. Application of the kinetic parameters, together with the heat balance performed by numerical analysis, allowed scale-up of thermal behaviour from mg- to kg-scale and simulation of SADT. The study presents the evaluation of the influence of the overall heat transfer coefficient U on the SADT value. The results obtained clearly illustrate also the dependence of SADT on the sample mass. The tenfold increase of the mass from 5 to 50 kg results in the decrease of the SADT from 50 to 43 °C. Determination of the reaction kinetics, describing the rate of heat generation, and the heat balance in the system, based on Frank-Kamenetskii approach, was calculated using AKTS Thermokinetics and Thermal Safety software

Thermal decomposition of AIBN, Part B ::simulation of SADT value based on DSC results and large scale tests according to conventional and new kinetic merging approach

The paper presents the results of the common project performed with the Federal Institute for Materials Research and Testing, Berlin, Germany (BAM) concerning the comparison of the experimental results with simulations based on the application of the kinetic-based method and heat balance of the system for the determination of the self accelerating decomposition temperature (SADT). The substantial potential of the kinetic-based method is illustrated by the results of the simulation of SADT of azobisisobutyronitrile (AIBN). The influence of sample mass and overall heat transfer coefficient on the SADT values were simulated and discussed. Simulated SADT values were verified experimentally with a series of large-scale experiments (UN test H.1 [1]) performed with packaging of 5, 20 and 50 kg of AIBN in an oven at constant temperatures. Additionally, the results of small-scale test H.4 for SADT determination based on the heat loss similarity as described in details in the UN Manual [1] were compared with the simulated data based on kinetic approach. The paper presents also the basic principles of a new kinetic analysis workflow in which the heat flow traces (e.g., DSC) are simultaneously considered with results of large-scale tests as e.g., H.1 or H.4. Application of the newly proposed kinetic workflow may increase accuracy of simulations of SADT based on results collected in the mg-scale and considerably decrease the amount of expensive and time consuming experiments in kg-scale tests