El Análisis cualitativo de datos con ATLAS.ti

Este artículo presenta las características, el procedimiento y la utilidad práctica del análisis de datos cualitativos en el proceso de investigación. Se trata de una tarea enormemente compleja para «dar sentido» a datos muy ricos y densos de significados en los estudios de carácter cualitativo. El trabajo describe cómo aplicar una herramienta informática, el ATLAS.ti, a este procedimiento analítico para su mayor sistematicidad, así como la mejor explotación y optimización de los resultados obtenidos. Se opta por un enfoque metodológico y con valor orientativo sobre el desarrollo autónomo de las tareas comunes del análisis de datos, como son la codificación y la categorización, la construcción de redes semánticas para la generación teórica, y la obtención de resultados parciales para plasmar en los informes de investigación.

Application of the N-alkane molecular alloys to thermally protected containers for catering

A thermally controlled transport device was designed and tested. As hot food needs to be transported at temperatures between 60 and 70ºC in order to avoid contamination by microorganisms, the use of Molecular Alloy Phase Change Materials (MAPCM) can lead to improvements in this field of application. A heat transfer numerical simulation of the box used for transporting the food was conducted. Despite obvious simplifications, a good agreement between numerical simulation and experimental results was obtained. Furthermore, we compared our experimental results with those from other experiments related to the transport of hot food. Here, pizza is taken as the example, and it is shown that delivering time can be increased three-fold.

Garcilaso de la Vega y Pedro Salinas: la voz a ti debida

This paper shows the relationship between two Spanish writers: Garcilaso de la Vega and Pedro Salinas; or better, the influence of the former over the latter. This influence may be noticed in different levels: the use of literary genres (eclogues, elegies or collections of verse), the conception of love, the use of myths and topics, the music of verse, etc. Some characteristics of Salinas’s style come clearly from Garcilaso (the intimacy, simplicity, orality, the dialogue, the use of the present tense and the first person, etc.). Our essay studies the influence of Garcilaso on the book Largo lamento, 1937?, written by Salinas at the same time as an essay about the renaissance poet —in addition of other unpublished works and his personal correspondence—, in order to show the presence of Garcilaso in his mind and all of his production

Vacancy-assisted domain-growth in asymmetric binary alloys: A Monte Carlo Study

A Monte Carlo simulation study of the vacancy-assisted domain growth in asymmetric binary alloys is presented. The system is modeled using a three-state ABV Hamiltonian which includes an asymmetry term. Our simulated system is a stoichiometric two-dimensional binary alloy with a single vacancy which evolves according to the vacancy-atom exchange mechanism. We obtain that, compared to the symmetric case, the ordering process slows down dramatically. Concerning the asymptotic behavior it is algebraic and characterized by the Allen-Cahn growth exponent x51/2. The late stages of the evolution are preceded by a transient regime strongly affected by both the temperature and the degree of asymmetry of the alloy. The results are discussed and compared to those obtained for the symmetric case.

Eletroxidação do etanol em eletrodos de Ti/IrO2

It has been carried out an investigation of ethanol electro-oxidation on Ti/IrO2 electrodes. The experimental results show a high selectivity towards acetaldehyde formation thus, offering potential advantages in cost and availability of raw material. It has been observed that the electrode is partially blocked by a film formed after the oxidation of the starting material which can be removed by pulse technique between RDO and RDH onset. The mechanism and the selectivity of the product formed is presented.

Estudo do biomaterial Ti-6Al-4V empregando-se técnicas eletroquímicas e XPS

The Ti-6Al-4V alloy used as biomaterial has been used over the last years. The literature shows controversies concerning the kind and the chemical composition of the film naturally and elctrochemically formed on the surface of the titanium alloy. The presente work studies the film composition before and after the electrochemical polarization tests using the x Ray photoelectron spectroscopy (XPS) technique. The results showed that the film naturally formed on the metallic surface is constituted of a variety of oxides which do not cover the whole surface of the metallic alloy and therefore, metallic Ti, Al and V can be found on the uncovered areas. The tests of XPS made after the polarization up to 4V (SCE) showed that the electrochemically formed film is constituted only of TiO2 and that the peak current observed around 1,5 V (SCE) is due to the oxidation of any kind of titanium oxide or the growth of the film.

Mentre ti lascio, o figlia

Äänitetty: 7.-8.5.1953, Los Angeles.

Estudo de efeito dos sais precursores sobre as propriedades eletrocatalíticas de eletrodos de Ti-SnO2/Sb preparados por decomposição térmica

The physical and electrochemical properties of Ti-SnO2/Sb electrodes obtained by the thermal decomposition of solutions of the precursor salts SnCl2×2H2O/SbCl3 and SnSO4/Sb2(SO4)3 were investigated. The reversibility of the cyclic voltammetric response of the Fe(CN)6(4-)/Fe(CN)6(3-) redox couple was assessed using the obtained electrodes. Their catalytic activity for the oxygen-evolving reaction and maximum capacity for electronic transfer were also evaluated by potential and current linear scans in 0.5 mol L-1 H2SO4. Additionally, scanning electron microscopy analyses allowed the visualization of the morphology of the oxide films obtained. The best results were presented by the electrodes obtained from the chloride salt precursors.

Commodity Price Driven Risk Management from Viewpoint of High Grade Steel Alloys

The study of price risk management concerning high grade steel alloys and their components was conducted. This study was focused in metal commodities, of which nickel, chrome and molybdenum were in a central role. Also possible hedging instruments and strategies for referred metals were studied. In the literature part main themes are price formation of Ni, Cr and Mo, the functioning of metal exchanges and main hedging instruments for metal commodities. This section also covers how micro and macro variables may affect metal prices from the viewpoint of short as well as longer time period. The experimental part consists of three sections. In the first part, multiple regression model with seven explanatory variables was constructed to describe price behavior of nickel. Results were compared after this with information created with comparable simple regression model. Additionally, long time mean price reversion of nickel was studied. In the second part, theoretical price of CF8M alloy was studied by using nickel, ferro-chrome and ferro-molybdenum as explanatory variables. In the last section, cross hedging possibilities for illiquid FeCr -metal was studied with five LME futures. Also this section covers new information concerning possible forthcoming molybdenum future contracts as well. The results of this study confirm, that linear regression models which are based on the assumption of market rationality, are not able to reliably describe price development of metals at issue. Models fulfilling assumptions for linear regression may though include useful information of statistical significant variables which have effect on metal prices. According to the experimental part, short futures were found to incorporate the most accurate information concerning the price movements in the future. However, not even 3M futures were able to predict turning point in the market before the faced slump. Cross hedging seemed to be very doubtful risk management strategy for illiquid metals, because correlations coefficients were found to be very sensitive for the chosen time span.

Biomateriais: deposição de hidroxiapatita sobre superfície de Ti-cp modificada por aspersão térmica

The osseointegrated titanium implants are reliable and safe alternatives to treatments for long periods of time. For surface modification, thermal aspersion of TiO2 was used. The samples with and without TiO2 were treated with NaOH and SBF in order to obtain a layer of HA. Characterization was done by SEM and FTIR. The images of HA obtained by SEM show a uniform morphology and a porous structure with spherical particles. The IR spectra show that the surface of Ticp/ TiO2 is more favorable for the HA deposit, as can be seen by the increase of the crystalline structure and the very intense and defined bands of the OH group of HA that is verified about 3571 and 630 cm-1. Thus the Ticp/ TiO2 surface presents a satisfactory nucleation of HA when compared to Ticp.

Aplicação de Zr/Ti-PILC no processo de adsorção de Cu(II), Co(II) e Ni(II) utilizando modelos físico-químicos de adsorção e termodinâmica do processo

The aim of this investigation is to study how Zr/Ti-PILC adsorbs metals. The physico-chemical proprieties of Zr/Ti-PILC have been optimized with pillarization processes and Cu(II), Ni(II) and Co(II) adsorption from aqueous solution has been carried out, with maximum adsorption values of 8.85, 8.30 and 7.78 x10-1 mmol g-1, respectively. The Langmuir, Freundlich and Temkin adsorption isotherm models have been applied to fit the experimental data with a linear regression process. The energetic effect caused by metal interaction was determined through calorimetric titration at the solid-liquid interface and gave a net thermal effect that enabled the calculation of the exothermic values and the equilibrium constant.

Degradação fotoeletroquímica de corantes dispersos em efluente têxtil utilizando fotoanodos de Ti/TiO2

The degradation of disperses dyes in aqueous solution and in effluents from textile industry has been investigated by photoelectrocatalytic oxidation using nanoporous thin films electrodes of Ti/TiO2. Samples of dispersil black dye and dispersil blue dye after 300 min of photoelectrolyzed at applied potential of +1.0 V and UV irradiation exhibited 100% of discoloration and 90% and 64% reduction total organic carbon, respectively. The proposed method was applied with success in a textile industry effluent containing residues of these dyes, which after 300 min of treatment leads to reduction of 60% of COD and 64% removal of TOC.

Estudo da fotocatálise heterogênea sobre Ti/TiO2 na descoloração de corantes sintéticos

The main goal of this paper was to study the degradation of synthetic dyes using photoelectrocatalytic properties of particulate films of TiO2 supported on plates of titanium and stimulated by UV-Vis radiation. The dyes decolorizations were measured using spectrophotometric methods to verify which the conditions on Ti/TiO2 electrode was the best for the photoelectrodegradation of them. The results showed that decolorization rates were higher than 90% during a period of 270 min. FT-IR spectroscopy showed that intermediate substances were formed after the decolorization and N=N group/aromatic structures were preserved independently of the specific structure of the dyes.