Showing papers by "Francisca Puertas published in 1992"
TL;DR: In this paper, the Lambert-Beer law slopes for four nitrates in KBr medium were determined and the L-B law was used for identification and quantitative analysis of these nitrates.
Abstract: Infrared spectra of sodium and potassium alkaline-metal nitrates and magnesium and calcium alkali-earth nitrates in solid phase had been recorded in order to assign the fundamental bands. The influence of the dispersal medium (alkaline halide), employed in the solid sample preparation have been discussed. The quantitative measurements of the band in ten sities at 1387 cm -1 (present in the I.R. spectra of the four nitrates in KBr medium) allowed us to determine the Lambert-Beer law slopes for each compound. These values are differents (bearing in mind experimental random errors), so we have could to affirm the nonexistence of solid solution between the nitrate and the alkaline halide medium. The L-B law obtained by us can be used for the Identification differentiation and quantitative analysis of these nitrates in solid phase, even if they are present in a very low concentration.
6 citations
TL;DR: In this paper, the main diffraction Unes corresponding to the components of hydrated portland cement and high alumina cement, are given, and the most significative changes of the hydrated phases of both cements when heated are shown.
Abstract: Instrumental techniques are indicated and the most adequated methodologies for determining the nature of the binder in concretes are explained. These methods are:
a) Determination of the Silicic Moduli through chemical analysis of the sample. This test reveais very different values between cement portland based concrete and high alumina cement based concretes.
b) X-ray diffraction. It is considered as the best method. In the present paper the main diffraction Unes corresponding to the components of hydrated portland cement and high alumina cement, are given.
As complementary methods having as limited use, DTA and TG are studied. The most significative changes of the hydrated phases of both cements when heated are shown.
A valoration of the Oxine test is also done as well as a description of using the characteristic colour of the high alumina cement as a practical indicator for determining its presence in concretes. Finally, comments on the significance of the presence of different CaCO 3 polymorhisms in portland cement concrete and high alumina cement concretete are also done.
4 citations