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Direct reading thermometric analysis

A rapid method for serial analysis in industry

Journal of Thermal Analysis and Calorimetry
Author:
I. Sajó
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The methods elaborated for the thermometric determination of the component to be analyzed in samples containing several interfering components are described. The following possibilities have so far been found for performing the determinations: The application of selective or partially selective reactions. Increasing the selectivity of the reactions by masking the interfering components. Increasing the selectivity of the reactions by utilizing the differences in behaviour of the various components towards the reagent, as for instance, differences in solubility, in stability constants, in the variation of the stability constants with pH, in the reaction rate. The use of indirect methods. Finally the correction of the interfering effect of certain components by calculation in the case of binary and multicomponent systems.

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Bedrock has an essential role in the formation of soils, it fundamentally determines mineral composition. The present research focuses on the minerals in forest soils formed in the Bükk Mountains (NE Hungary). The composition of soil minerals was in accordance with the geological features as well as with the changes in climate and vegetation, which provide a basis for tracking the past of the soil formation mechanisms (Nemecz, 2006). Thus, by studying the mineral composition the formation processes and development of the soils can be unveiled.According to the findings it can be assumed that the investigated soils, although formed primarily on solid limestone, cannot be the products of the weathering of limestone solely, as they also contain significant amounts of silicates. The major part of the soil forming materials presumably originates from earlier dust fallings or from alluvial deposits by erosion. The former assumption is confirmed by the fact that the investigated area is located at a high altitude, thus significant amounts of eroded material could only originate from a short distance, where the bedrock also consists of limestone. Further research is needed for more detailed knowledge on the mineral composition of the soils, thus on the development of the soils and the bedrock of the investigated area.

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Abstract  

Cellulose acetate (CA) was modified with caprolactone (CL) under various reaction conditions in an internal mixer. The thermal behavior and relaxation transitions of the samples were determined by dynamic mechanical analysis and differential scanning calorimetry. Various relaxation transitions were detected in externally and internally modified cellulose acetate by DMTA. These were assigned to the glass transition of the main chain, to the movement of single glucose units and to hydroxymethyl groups. The β′ transition must belong to structural units larger than a single glucose ring and their formation must depend on sample preparation conditions. No transition could be assigned to grafted polycaprolactone (PCL) chains by DMTA. Contrary to other groups, we could not detect even the transitions of modified CA by DSC. Only the crystallization of oligomeric PCL homopolymer was observed mostly when it diffused to the surface of the sample.

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The first part of the paper gives a review of the literature dealing with thermochemical determinations of SiO2 and Al2O3 in hydrofluoric acid solution. The results of experiments with constant samples weights of 700 mg SiO2 and about 100 mg Al2O3 in hydrofluoric acid solution with differently combined injection reagents are discussed. The determinations were based on the analysis of precipitated sodium aluminium silicates.

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