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Abstract  

High-resolution thermogravimetry was used to study the thermodesorption of octane from ammonium nitrate (AN) prills with different porosities. The samples were wetted by immersion in octane. Multiple steps were obtained from the measured mass-loss curves, which reflect the evaporation of the excess liquid, as well as the thermodesorption of octane from the pores and the surface of the AN prills. The quantity of octane desorbed in these steps was correlated with the volume in the pores and the amount adsorbed on the surface, and used to estimate the adsorption capacity, porosity and surface area of AN prills. The results were also compared to observations from scanning electron microscopy.

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Volatility rate by thermogravimetry

An ASTM interlaboratory study for ASTM international E2008

Journal of Thermal Analysis and Calorimetry
Authors: Q Kwok and R Seyler

Abstract  

ASTM Committee E37 on Thermal Measurements published a new test method 'Standard Test Method for Volatility Rate by Thermogravimetry' in June 1999 with the designation E 2008. This approach to assessing volatility utilizes an extension of the pinhole technology previously employed by E37 for vapor pressure determinations using differential scanning calorimetry (ASTM E 1782). After publication of the test method E 2008, an Interlaboratory Study was undertaken to develop a 'Precision and Bias' statement to be assigned with the test method. This paper provides some background data that supports the claim that E 2008 is generally insensitive to experimental conditions other than temperature. The Interlaboratory Study showing the statistical review is also discussed.

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Abstract  

The thermal properties of Alex, a nanosized Al powder, were determined using various techniques, including DSC, TG, simultaneous TG-DTA (SDT) and accelerating rate calorimetry (ARC). The results demonstrate that the specific heat capacities of nano and micron size Al powders are similar between 30 and 400C. Dynamic and isothermal methods were used to determine the kinetic parameters for the oxidation reaction of Alex, which was detected at an onset temperature of 481C. The results obtained were in good agreement with each other. From the ARC experiments, exotherms were detected near 340 and 260C for experiments started at ambient pressure and at 0.72 MPa, respectively.

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Abstract  

Three bio-fuels with or without additives and their fly ash samples were characterized using simultaneous Thermogravimetry-Differential Thermal Analysis-Fourier Transform Infrared Spectrometry-Mass Spectrometry (TG-DTA-FTIR-MS), X-ray Diffraction (XRD), X-ray Fluorescence (XRF), and Scanning Electron Microscopy-Energy Dispersive Spectrometry (SEM-EDS). The results show that the additives increase the reactivity of the bio-fuel during combustion. The additives also significantly decrease the amount of unburned carbon in the fly ash. The additives affect the compounds formed in the fly ash sample, and consequently the thermal behaviour of the fly ash. The fly ash samples are thermally stable in air up to 100C. The fly ash samples contain fine particles with irregular shape, small round particles, and large hollow spherical particles with entrapped gases.

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Abstract  

BTAw (bis-(1(2)H-tetrazol-5yl)-amine monohydrate) has recently been considered for use as a low-smoke pyrotechnic fuel. There is relatively little information available in the literature concerning the thermal properties of BTAw or its precursors. In the present work, various thermoanalytical experiments were performed on BTAw and BTA (bis-(1(2)H-tetrazol-5yl)-amine) in an effort to better characterize the thermal stability and decomposition of these compounds. Variable heating rate studies were carried out on BTAw samples in a helium atmosphere using DSC and TG. Two steps were seen in the results: dehydration followed by decomposition. Kinetic parameters were determined for both of these steps using a number of methods. Experiments using simultaneous TG-DTA coupled with FTIR and MS were performed on BTAw in both helium and dry and CO2 free air atmospheres, and evolved gas analysis was used to determine the gaseous decomposition products. The thermal stability of BTAw and BTA was examined using accelerating rate calorimetry (ARC).

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