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Journal of Thermal Analysis and Calorimetry
Authors:
Lisardo Núñez-Regueira
,
J. Proupín-Castiñeiras
,
J. Rodríguez-Añón
,
Maria Villanueva-López
, and
O. Núñez-Fernández

Abstract  

The design of a rigorous experimental procedure is the basis for any environmental study. In this work, the basic criteria are established for determination of soil health using microcalorimetry as the main technique complemented by the study of physical (temperature, moisture, porosity, hydraulic conductivity, density and plasticity), chemical (pH and C to N ratio) and biological features (most probable number of microorganisms and organic matter content), and also environmental properties in the form of bioclimatic diagrams. The design was elaborated using as a reference a humic eutrophic-Cambisol subjected to afforestation with P. pinaster Aiton situated in Viveiro (Galicia, NW Spain). Main results of this study refer to total heat evolved during the processes (2.65 to 3.81 J g–1), time to reach the maximum of the peak from 16.17 to 19.29 h, and microbial growth rate constant from 0.0732 to 0.1043 h–1. These results change over the year as they are influenced by the action of environmental parameters over soil microbial activity. The results are in close agreement with some others previously reported using different experimental techniques.

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Abstract  

This work is a ‘historical’ revision of the evolution of an experimental procedure developed by Prof. Lisardo Nez and his research group TERBIPROMAT to study the sustainability and the soil health state. From the very beginning, in 1993, the microbial activity was the main bioindicator selected to analyse the ‘soil health state’. For this reason, a microcalorimetric technique was used lately to analyse the influence of different human activities such as reforestations, agricultural exploitation or pollution on the microbial activity in different soils. Microcalorimetry is the main scientific technique used in this research to follow the stimulation of the microbial activity by addition of glucose. The data obtained were complemented by a study of physical, chemical and biological parameters of soil and allowed to follow the microbial activity in soils of Galicia (Spain) along the year. The final results, still in revision, will be helpful in establishing a data basis for real maps of the ‘health state’ of different soils. Such maps could be used to design processes that help us to decide how we should exploit soils ensuring their sustainability.

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Abstract  

Compositions of the solid solvates of C60 with 1,2-dichlorobenzene and 1,3,5-trimethylbenzene were determined with the help of experimental procedures developed. Possible correlations between compositions and thermodynamic properties were discussed.

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theoretical study of CB combustion using thermogravimetry has shown the importance of limitations to oxygen transport within the sample bed in the combustion control. When a kinetic constant is extracted from a thermogravimetric experiment, the experimental

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Abstract  

Adsorption equilibria of pure gases and binary gas mixtures can be measured with a new magnetic suspension balance. For this measurement no additional concentration measurement is required, neither for the gas phase nor for the adsorbed phase. The new instrument allows gravimetric adsorption measurements in a wide range of pressure (UHV...50 MPa) and temperature (210 K...570 K) to be performed. The experimental procedure and the instrument set up is fairly easy and can be compared to pure gas adsorption experiments. The new instrument and experimental procedure have been tested by performing coadsorption measurements with CO/H2 mixtures on a commercial 5A zeolite.

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Abstract  

In estuarine environments there are important spatial and temporal changes in both salt and suspended load concentrations. An experimental procedure have been developed to produce kinetic parameters being representative of the natural environment studied, and we have investigated the effect of salinity and suspended load concentration to the kinetics of the uptake. These results are encouraged by recent advances in environmental modelling concerning to radionuclide dispersion in aquatic natural systems and involving non-equilibrium processes. Experiments are carried out with unfiltered water samples from the Odiel estuary (Southwest of Spain), with133Ba tracer to illustrate experimental procedures.

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Abstract  

Several attempts have been made to synthesize mixed-valence compound of antimony at low temperature in view of studying the isotopic exchange in solids. The experimental procedure for the synthesis, at 263 K of Cs4(SbIIICl6)(SbVCl6) has been established. This compound seems very promising for isotopic exchange studies in the solid state.

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Abstract  

Comments are given on the kinetic studies of isotope exchange in heterogeneous systems, reported in the paper by J. PLICKA, J. CABICAR, A. GOSMAN and K. TAMBERG, published in J. Radioanal. Nucl. Chem., 88 (1985) 325–336. Both experimental procedure and interpretation of the results are discussed.

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Abstract  

The instrumental determination of the103Rh/n, 2n/102Rh and103Rh/n, 2n/102mRh reaction cross-sections was carried out averaged over a fission spectrum. The experimental procedure is described and the results are discussed, in comparison with previous published data.

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Abstract  

Cerenkov counting efficiencies for a large number of radionuclides formed by (n, γ) reactions and used in the field of activation analysis have been obtained by two different experimental procedures. A comparison between the Cerenkov counting technique and scintillation low-resolution gamma-ray spectrometry is also presented. Results are summarized in tables and briefly discussed.

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