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Abstract  

The use of non-aqueous deacidification procedures as a preventive conservation measure to assist in retarding the deterioration of painting canvases has been suggested by the Conservation Department of the Tate Gallery [1]. The reverse sides of paintings are treated with commercially available MMC solution (methoxy magnesium methyl carbonate). The aim of this paper is to describe how dynamic mechanical thermal analysis can be used to evaluate the effects of this treatment. Measurements are described on modern commercially primed canvas samples [2] which show that the MMC treatment does cause an increase in the modulus or stiffness of the primed canvas materials but that the effect on theT g is minimal. The response of the treated materials to variations in relative humidity has also been studied and indications are that the response of treated canvases to variations in relative humidity differs from those of the untreated canvases.

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Summary Mechanical mixtures containing zirconia xerogel and increasing amount of crystalline yttria up to 40 mol%, were hydrothermally treated by microwave route at 110°C for 2h. All the treatments were performed in the presence of (KOH+K2CO3) mineralizer solution at concentration 0.2 M. Amorphous and hydrated ZrO2-Y2O3 solid solutions with yttria content up to 33.3 mol% (corresponding to Zr/Y molar ratio equal to 1), resulted after the hydrothermal treatments. A remarkable reduction of the surface area has been detected at increasing yttria content of the amorphous phases with a corresponding increase of the exothermic peak of crystallization. A mechanism of reaction for the formation of the amorphous solid solutions has been proposed.

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Abstract  

Fixation of137Cs,144Ce,60Co,90Sr,240Th and233U from aqueous and phosphate media on bentonite clay was studied. The fixation of the radioactive ions on bentonite surfaces was dependent on the pH behavior of the metal ions. A method was proposed to use bentonite as an absorbent of ions from simulated radioactive waste as a treatment step.

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Abstract  

Different iron hydroxide precipitation processes simulating radioactive waste, treatment have been investigated by Mössbauer spectroscopy at room temperature and at 80 K. Magnetic oxides (hematite or magnetite) partially affected by superparamagnetic relaxation have been observed. The crystallization degree and the particle size depend on the concentration and the addition order of chemicals. Much smaller particles were precipitated with Ca(OH)2 than with NaOH as neutralization reagent.

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Abstract  

A natural laumontite from the Isle of Skye, Scotland has been examined as a candidate material for aqueous nuclear waste treatment, and its fully Ca exchanged form has been shown to be Sr selective. Laumontite has a good pH stability in acid and alkaline media. The materials used have been characterized by wet chemical analysis, XRD and thermal analysis. The studies include both ion exchange kinetics and equilibrium isotherm studies which tend to confirm simple Kd tests.

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Abstract  

Gamma-irradiation of treated piggery slurry was studied as a possible way of posttreatment. Biologically non-degradable substances (cellulose, lignin, etc.) were almost completely oxidized at 90–100 kGy radiation doses. TOC values indicated complete oxidation of organic carbon to CO2. Radiation doses of 10 and 50 kGy have not changed the biodegradability of irradiated substances. By -irradiation after chemical and biological treatment it is possible to get highest quality effluent with COD values lower than 40 mg.l–1.

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Abstract  

Radionuclide concentrations in digester sludge and effluent samples from Hamilton and Dundas sewage treatment plants, located at the western tip of Lake Ontario, have been determined by high-resolution γ-ray spectrometry. The radionuclides51Cr,75Se and131I, which are used in nuclear medicine procedures, were found in sludge samples. Very low concentrations of51Cr, entering Lake Ontario through the Hamilton plant effluent discharge, have little effect on lake water quality.

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Abstract  

Via the thermal treatment of natural phosphates and their analysis, it was proved that the decrease in their solubility in the interval 400–550C is an indication of the degree of incorporation of OH groups into the apatite structure of phosphates, whereas the solubility at 950C is an indication of the degree of incorporation of the non-volatile components. The higherR 950, the more extensive this substitution, and the more reactive the natural phosphate.

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Abstract  

Synthetic Fe—Mn alkoxide of glycerol samples are submitted to controlled heating conditions and examined by IR absorption spectroscopy. On the other hand, the same sample is studied by infrared emission spectroscopy (IRES), upon heating in situ from 100 to 600°C. The spectral techniques employed in this contribution, especially IRES, show that as a result of the thermal treatments ferromagnetic oxides (manganese ferrite) are formed between 350 and 400°C. Some further spectral changes are seen at higher temperatures.

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Abstract  

The number of the cities with canalized water and sewage treatment stations has increased lately and consequently having in mind the great concern on environment preservation and the quality of the water used by society. However, these stations are nowadays causing another kind of problem: a huge quantity of sludge as residue. Due to the implication of the residue on the environment and, consequently, to human life quality, performing of an accurate investigation about the components of such sludge, as well as the thermal stability of this residue in the environment become necessary. This paper presents a study on sludge from water and sewage treatment station, as well as the thermal characterization of residue. Such study was performed through FTIR, atomic absorption, thermoanalytical (TG/DTG, DTA) techniques, that made it possible to observe that the main components of the sludge are clay, carbonates and organic substance, presenting a low rate of metals and a unique thermal behavior since the sludge from the treatment station has a higher thermal stability.

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