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Abstract  

Simultaneous DSC-TG and DTA-TG were used to investigate the calatytic effect of the metal on the thermal decomposition of a cellulose matrix containing small copper particles. The techniques were also used to demonstrate the effect of the metal particles on the subsequent activation of the carbon matrix, a process which develops the pore structure necessary to expose the metal particles to the gas phase. Temperature programmed desorption was used to study the initial mass loss found on activation. To quantify the catalytic effect of the copper particles on the activation process an estimate was made of the activation energy of the catalysed and uncatalysed reactions. The work gives valuable information on the processes involved in the preparation of a new range of metal-carbon catalysts.

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Characterisation and analysis of micro-contaminants in industrial polymers

Application of TP-SIP-MS scanning electron microscopy and SEM X-ray microanalysis

Journal of Thermal Analysis and Calorimetry
Authors: P. Barnes, G. Parkes, and P. Sheridan

Abstract  

Analysis of very small particles can present problems. This paper describes the application of temperature programmed solid insertion probe mass spectrometry (TP-SIP-MS), scanning electron microscopy and SEM X-ray microanalysis to the identification of foreign particles present in an industrial product. The relative advantages and limitations of the techniques are discussed. It is shown that TP-SIP-MS is a powerful tool for such work and complements the use of more conventional microanalytical methods.

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Abstract  

The reduction of bulk and supported copper oxide was investigated using Constant Rate-Temperature Programmed Reduction (CR-TPR) and conventional linear heating rate TPR. Linear heating profiles indicated that the reduction of supported samples was more facile than that of the bulk oxide. CRTA results revealed that both supported and bulk oxide samples were reduced via a mechanism involving a nucleation step and/or auto-catalysis. The increased reducibility of the supported samples is attributed to a higher dispersion which provides a larger reactive surface area and a high concentration of defects at which reduction is initiated.

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Abstract  

Sample controlled thermal analysis techniques such as constant rate transformation analysis or stepwise isothermal analysis, where the transformation rate of the sample itself is used to control the experiment, are becoming increasingly important [1]. The measurements are normally carried out using changes in the sample mass, sample dimensions or in the evolved gas, as the property used to control the experiment, and enable reactions to be studied in greater detail than is possible using linear heating techniques. A new approach is described here where a thermomicroscopy system has been developed to enable the intensity of the light reflected or transmitted by the sample to be used as the controlling signal [2].

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Abstract  

This paper describes a new instrument for performing thermal analysis using microwaves both as a form of heating and as a novel means of detecting thermally induced transformations in materials. Results are presented for a selection of processes including decompositions, dehydrations and phase changes. The capability of the instrument to be coupled with ancillary techniques such as EGA is also demonstrated.

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Abstract  

The application of the charged particle X-ray excitation technique (CPXE) to the problem of determination of residues from gun firing is described. Preliminary results indicate that certain elements, including S, Ba, Fe, and Pb can be detected in statistically significant larger amounts on firing hands than on nonfiring hands with 90 to 98% confidence limits. Results for other elements including K, Ca, Sb, Cr, Mn, Ni, Cu, are also discussed. The simplicity on the technique, together with the number of elements detected, offers advantages over other techniques for firearm discharge residue detection.

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Abstract  

The application of the changed particle X-ray excitation technique (CPXE) to the problem of determination of residues from gun firing is described. Preliminary results indicate that certain elements, including S, Ba, Fe, and Pb can be detected in statistically significant larger amounts on firing hands than on nonfiring hands with 90 to 98 percent confidence limits. Results for other elements including K, Ca, Sb, Cr, Mn, Ni, Cu, are also discussed. The simplicity of the technique, together with the number of elements detected, offers advantages over other techniques for firearm discharge residue detection.

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