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Abstract
A calorimetric procedure is developed to study the effect on the soil of the effluents resulting for the anaerobic digestion of slaughtering houses residues. DSC was used to study the pyrolysis properties of the effluent and the soil while isothermal calorimetry is applied to study the microbial activity in the effluent and to assess on its effect on the microbial activity of the soil where the industrial digester will be situated. The calorimetric data were studied together with the chemical and biological properties of that residue. Results showed that effluent is constituted by low levels of carbon and high levels of nitrogen. The power-time curves of the effluent have the typical shape of microbial growth yielding microbial growth rate constants between 0.37 and 0.53 h−1 for about 4 and 11 h. The addition of the effluent to the soil decreases the heat of pyrolysis with time and stimulates the heat flow rate of the microbial metabolism.
The thermal decompositions of divalent cobalt, cadmium, nickel and copper salicylates and intermediates formed during the decomposition processes were investigated by means of thermogravimetry. Two intermediates were identified in each case, except for copper(II) salicylate.
Abstract
Angra dos Reis/Itaguai region of the state of Rio de Janeiro, Brazil, is a very problematic area due to the instability of slope and landslides, due to geological and geomorphological conditions and to the significant and continuous human occupation over favorable areas is prone to the triggering of landslides. The samples were analyzed by thermogravimetry (TG), derivative thermogravimetry (DTG) and differential thermal analysis (DTA). This paper analyzes and characterizes the clay minerals and presence of water, gravitational mass movements’ sites and compares it with sites where gravitational mass movements do not occur. Indeed, this analysis also attempts to verify the presence of minerals.
The preparation of Ni(CN)21.5M (M=morpholine) and the thermal study of this and NiBr23M, Nil24M and Ni(NCS)24M are described. The thermal treatment of these compounds leads to the isolation of Ni(CN)2M, Ni(CN)20.5M, NiBr22M, Nil23M, Nil21.5M, Ni(NCS)22M and Ni(NCS)2M. With the exception of NiBr22M and Ni(NCS)22M, all intermediate species are reported here for the first time. Magnetic and spectral studies have been carried out to determine the mode of coordination and stereochemistry of the complexes. The thermal study includes the determination of stability, apparent activation energy and reaction orders, and reaction enthalpies.
The thermal behaviour of [CoCO3(NH3)4]2SO4 · 3H2O was studied using X-ray diffraction diagrams, DTA, TG and heating at constant temperatures for different periods of time. The X-ray study was made in order to characterize with the powder diagrams the phases obtained and to follow the reactions of the complex when heated in air up to 800‡. A parallel infrared spectral study was also made. The results obtained by the various experimental methods were compared with the theoretical weight losses.
Abstract
A complete methodology for 226Ra and 228Ra determination by alpha-particle spectrometry in environmental samples is being applied in our laboratory using 225Ra as an isotopic tracer. This methodology can be considered highly suitable for the determination of these nuclides when very low absolute limits of detection need to be achieved. The 226Ra determination can be performed at any time after the isolation of the radium isotopes from the analyzed samples while the 228Ra determination needs to be carried out at least six months later through the measurement of one of its grand-daughters. The method has been validated by its application to samples with known concentrations of these Ra nuclides, and by comparison with other radiometric methods.
The 1 ∶ 4 complexes of cobalt (II) and manganese (II) thiocyanates with morpholine (Morph), [M(NCS)2(Morph)4] (M=Co, Mn), were prepared and studied by means of thermogravimetry, derivative thermogravimetry and differential scanning calorimetry. By thermal treatment of the above compounds, the 1∶2 and 1∶1 complexes, [M(NCS)2(Morph)2] (M=Co, Mn; n=1, 2), were formed. Magnetic data, infrared and electronic spectra and molar conductance values for the compounds are reported. All the complexes contain N-bonded morpholine and the 1∶4 complexes are suggested to have a monomericcis pseudooctahedral structure with N-bonded thiocyanate, whereas the 1∶2 and 1∶1 complexes are considered to have a six-coordinated polymeric configuration involving bridging NCS groups.
