An improved procedure for obtaining and maintaining well characterized partial water saturation states on concrete samples to be used for mass transport tests

A conditioning procedure is proposed allowing to install into the concrete specimens any selected value of water saturation degree with homogeneous moisture distribution. This is achieved within the least time and the minimum alteration of the concrete specimens. The protocol has the following steps: obtaining basic drying data at 50 °C (water absorption capacity and drying curves); unidirectional drying of the specimens at 50 °C until reaching the target saturation degree values; redistribution phase in closed containers at 50 °C (with measurement of the quasi-equilibrium relative humidities); storage into controlled environment chambers until and during mass transport tests, if necessary. A water transport model is used to derive transport parameters of the tested materials from the drying data, i.e., relative permeabilities and apparent water diffusion coefficients. The model also allows calculating moisture profiles during isothermal drying and redistribution phases, thus allowing optimization of the redistribution times for obtaining homogeneous moisture distributions.

Dispersive liquid–liquid microextraction for metals enrichment: A useful strategy for improving sensitivity of laser-induced breakdown spectroscopy in liquid samples analysis

A rapid and efficient Dispersive Liquid–Liquid Microextraction (DLLME) followed by Laser-Induced Breakdown Spectroscopy detection (LIBS) was evaluated for simultaneous determination of Cr, Cu, Mn, Ni and Zn in water samples. Metals in the samples were extracted with tetrachloromethane as pyrrolidinedithiocarbamate (APDC) complexes, using vortex agitation to achieve dispersion of the extractant solvent. Several DLLME experimental factors affecting extraction efficiency were optimized with a multivariate approach. Under optimum DLLME conditions, DLLME-LIBS method was found to be of about 4.0–5.5 times more sensitive than LIBS, achieving limits of detection of about 3.7–5.6 times lower. To assess accuracy of the proposed DLLME-LIBS procedure, a certified reference material of estuarine water was analyzed.

Representaciones de género en la publicidad de alimentos: un análisis de contenido

El análisis de contenido del mensaje mediático desde una perspectiva de género cuenta ya con una abundante bibliografía. En el caso de la publicidad, gran parte de los estudios realizados se han centrado en muestras genéricas de contenidos publicitarios o en aquella publicidad tradicionalmente asociada a uno u otro género. Sin embargo, pocos autores han analizado los contenidos de género de la publicidad relativa a productos de alimentación, a pesar de la estrecha relación entre estructuras de género y los procesos sociales de compra y preparación de alimentos. En este ámbito se sitúa, precisamente, nuestra investigación. Los principales resultados obtenidos muestran claras diferencias de género en las piezas publicitarias: tanto en términos de presencia cuantitativa como en la asignación de determinadas características.

Gender portrayals in food commercials: a content analysis of Spanish television advertisements

Content analysis of media messages from a gender perspective has a long tradition. In the particular field of advertising, most of the researches have been focused on generic samples of advertisements or on the advertising traditionally associated to a masculine or a feminine audience. However, few authors have analyzed gender contents in food advertising, in spite of the close relationship between gender structures and the social processes of food purchase and preparation. Thus, gender representations in food advertising broadcast in Spanish television are analyzed in this article. The main results obtained show clear gender differences. For example, there is a clear predominance of masculine voices over and a more balanced situation regarding protagonists. Besides, feminine protagonists are more frequently located indoors, portrayed as attractive women and connected to advertising claims related to beauty or to the healthy qualities of the product.

Modification of Hematite Electronic Properties with Trimethyl Aluminum to Enhance the Efficiency of Photoelectrodes

The electronic properties of hematite were investigated by means of synchrotron radiation photoemission (SR-PES) and X-ray absorption spectroscopy (XAS). Hematite samples were exposed to trimethyl aluminum (TMA) pulses, a widely used Al-precursor for the atomic layer deposition (ALD) of Al2O3. SR-PES and XAS showed that the electronic properties of hematite were modified by the interaction with TMA. In particular, the hybridization of O 2p states with Fe 3d and Fe 4s4p changed upon TMA pulses due to electron inclusion as polarons. The change of hybridization correlates with an enhancement of the photocurrent density due to water oxidation for the hematite electrodes. Such an enhancement has been associated with an improvement in charge carrier transport. Our findings open new perspectives for the understanding and utilization of electrode modifications by very thin ALD films and show that the interactions between metal precursors and substrates seem to be important factors in defining their electronic and photoelectrocatalytic properties.