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  • Author or Editor: J. Miranda x
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Three major domal structures are trending northeast-southwest directions prevailed at El-Hasana area, northern part of Sinai Peninsula. These structures and their altered rock constituents attracted us to study these formations from geophysical view. The main target of this work is to establish the relation between these structures and Syrian Arc Tectonic System (SATS) prevailed at the studied area. The investigations were carried out using land magnetic survey, aeromagnetic, gravity and laboratory measurements.An intensive analysis using tectonic trend analysis and, 3D Euler deconvolution with different coefficients were applied to the potential field data. Also, cross-sections Euler deconvolution, Werner deconvolution and radial power spectrum have been applied. The results illustrate that most prevailed tectonics that could forming these anticlines are trending at N 35°–65° E direction which related to the Syrian tectonics (SATS) direction. The depth to the basement rocks ranges between 2 km at the southern parts to 2.3 km at the northern parts of the studied area.The magnetic susceptibility map was constructed using laboratory measurements for more than 120 collected rock samples along the surveyed area. The average values range between 0.7 × 10 −3 to 1 × 10 −3 SI for limestone samples, whereas the sandstone varies between 1 × 10 −3 to 1.5 × 10 −3 SI unit. The results show that the magnetic values are higher for the rock samples picked along the anticlinal structures.

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Particle induced X-ray emission (PIXE) and Rutherford backscattering spectrometry (RBS) were used to determine the concentrations of trace elements in samples of 12 tomato puree brands sold in the Mexican market. While RBS offered information about the main elements present in the matrix, PIXE gave results on trace elements. As a whole, data for 17 elements (C, N, O, Na, Mg, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, and Zn) were obtained. To evaluate the results, a comparison with brands from USA, Japan, Colombia, and Chile was carried out, using tomato purees produced following the domestic technology recipe. Additionally, the results were considered in the light of the Codex Alimentarius and the Mexican standard. It was found that all of the brands fall within the limits established by these standards, being of the same order of magnitude as the foreign brands.

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A study of provenance of obsidian artifacts from "site 25-Las Estacas", Quebrada de Jorquera (Copiapó, Northern Chile) was carried out by means of X-ray fluorescence, using radioactive sources. Obsidian samples from different Chilean geological regions, located in South Central Chile (Laguna del Maule volcanic area, sources of La Coloradas and La Plata), "Radal Siete Tazas" and the North of Chile (Copiapó Volcano) were analyzed. The analysis was performed using 109Cd and 241Am annular excitation sources and X-ray fluorescence. This allowed the determination of Fe, Cu, Rb, Sr, Y, Zr, and Ba concentrations on samples of ground obsidian from the aforementioned sites. The measured Rb, Sr, and Zr concentrations were used to construct discriminant diagrams, which clearly showed clustering of the samples from the different sources, and the association of the archaeological obsidian sample to the Copiapó Volcano source, which is geographically close to the site.

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The Mössbauer spectra of 29 nitroprussides have been measured and the parameters and correlated with the polarizing power Z/r2 of the outer cations. There is no overall correlation but there are limited groups in which a trend can be ascertained. In isoelectronic sequences such as Li+, Be2+; Mn2+, Fe3+, where the outer electronic shell remains fixed, while Z/r2 increases, a definite trend of decreasing and with increasing Z/r2 is observed.

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Lanthanide picrates with 1,3-dithiane-1,3-dioxide ligand were synthesized and characterized. Thermal decomposition of these compounds by TG/DTG and DSC and structural studies were performed. It was found that the compounds are comprised in a single isomorphous series and their thermal decomposition occurs as exothermic events. The final products were found to be lanthanide dioxysulfates.

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The neutron reflection method was applied for the determination of the bound water content and its spread in lateritic mineral. The aim of the work was to study the influence of bound water on the accuracy of the moisture measurement. The distribution of bound water in the mineral can be described by a normal Gaussian curve.

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The production cross sections of L-shell X-ray of some rare earth elements have been measured by collision of 12C4+ and 16O4+ ions of 0.5 to 0.75 MeV/amu. The results were compared with experimental data of other authors and with theoretical predictions gained by the ECPSSR and ECPSSR plus multiple ionization (ECPSSR+MI) models. For atomic parameters (fluorescence yields and probabilities for Coster-Kronig transitions) the role of several databases were studied. The ECPSSR theory underestimates cross sections when compared with experimental results obtained in the present work, but ECPSSR+MI has a better agreement with the experimental data.

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Proximate composition and physical parameters in nine quinoa cultivars were determined in order to establish differences among them and to contribute to their characterization. Faro, Pichaman, and Baer varieties cultivars were used. The aim of this research was to evaluate the physical and chemical properties and to characterize the protein fractions. All analysed properties showed significant differences between the cultivars. The physical measurements (weight, shape, size, and density) could be used for improving the technology associated with conditioning, transport, and storage of the grain. The protein content ranged from 15 to 18%, fat 6 to 8%, carbohydrates 70 to 74%, and ash from 3.5 to 4.4%, showing an outstanding nutritional profile. The relative quantity of soluble proteins (albumins and globulins) ranged from 40 to 65%, except in Faro variety cultivar, which presented 16%. The relative percentage of insoluble protein (prolamins and glutelins) ranged from 25 to 34%. The obtained information in this research could be useful in determining seed-quality, automating production, improving cultivation practices and technologies, and developing food products with enhanced nutritional qualities.

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The characterization of samples of painted plasters obtained from the archaeological site of Xochicalco, in Central Mexico, is presented. Elemental concentrations of the painted layers were obtained by using proton induced X-ray emission (PIXE). The main crystalline structures of the samples are identified with the help of X-ray diffraction (XRD), while the microstructure is studied by scanning electron microscopy (SEM). The information resulting from the application of these three techniques is used to achieve more accurate values for the elemental concentrations. Additional data regarding organic components of the paintings was obtained through Fourier transform infrared spectrometry (FTIR). Although the latter results only provided reliable data on inorganic components, they help to clarify the results from XRD and confirm those of SEM.

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