On the accessibility of Moodle 2 by visually impaired users,with a focus on mathematical content

In this paper we study the accessibility by visually impaired people of the learning management system (LMS) Moodle 2. The study is conducted by testing four different visually impaired subjects, with different degrees of disability and performing different tasks connected to different roles in the LMS. A peculiar focus is given to the accessibility of content involving mathematics. At the end of the paper, some recommendations to improve the accessibility of Moodle 2 are given.     

Solubility of supercritical gases in organic liquids

Chrastil (1982) [6] demonstrated that the solubility of a substance in a supercritical fluid (SCF) can be correlated with the density of the pure supercritical gas. Therefore, Chrastil's equation permits calculation of the supercritical phase composition of binary SCF + substance mixture based on the knowledge of the supercritical gas density and avoiding the use of equation of state based models.In this work, it is demonstrated that the supercritical fluid density also defines the liquid phase composition of binary systems; a density-dependent relationship is presented to calculate the solubility of supercritical gases in organic liquids. The isothermal solubility of several gases commonly employed in supercritical processing, such as carbon dioxide, methane, and ethane, in different organic liquids, including alkanes, alkenes, alcohols, acids, ketones, esters, terpenes and aromatic compounds, was successfully correlated as a function solely of the pure supercritical fluid density. As an application, pressure vs. composition phase diagrams of binary SCF + substance mixtures were obtained circumventing the use of equation of state models.     

Solid State Analysis of Metal-Containing Polymers Employing Mössbauer Spectroscopy, Solid State NMR and F EI TOF MALDI MS

Polymers in general and metal-containing polymers in particular are often sparingly soluble or insoluble, in contrast to small molecules. Thus, special significance is attached to characterization techniques that can be applied to the materials as solids. Here, three techniques are discussed that give structural information gained from the solid material. Mössbauer spectroscopy is a powerful technique that may give information on the structure about the metal-containing moiety for about 44 different nuclei. Its use in describing the structure of the product obtained from organotin dichlorides and the unsymmetrical ciprofloxacin is presented along with the reaction implications of the results. Solid state NMR is also a useful tool in describing the structure of metal-containing polymers and its use is briefly described. Finally, MALDI MS can be used to gain structural information. For many metals it is particularly useful because of the presence of different isotopes that allow the identification of units through comparison of these isotope abundances with ion fragment clusters. Each of these tools can provide important structural characterization information.     

Extraction of caffeine from natural matter using a bio-renewable agrochemical solvent

This paper reports experimental data on the pressurized liquid extraction of caffeine from green coffee beans and green tea leaves using ethyl lactate (ethyl 2-hydroxy-propanoate). This solvent is a new bio-renewable agrochemical solvent, naturally produced by fermentation from corn derived feedstock, which has been recently considered as a very suitable and environmental benign solvent for food industrial applications.Static extraction assays (one step during 10 min) were carried out in an Accelerated solvent extraction (ASE) system at three different extraction temperatures, namely 100, 150 and 200 °C. Extraction yield and caffeine recovery were determined and compared with those obtained when using other liquid solvents, such as ethyl acetate or ethanol. High recovery of caffeine (≈60%) was found in the extracts produced using ethyl lactate, which demonstrates the potential use of this green solvent for the extraction of caffeine from different vegetable sources.     

The changing role of life cycle phases, subsystems and materials in the LCA of low energy buildings

A detailed Life Cycle Assessment (LCA) has been conducted on a low energy family house recently built in Northern Italy. The yearly net winter heat requirement is 10 kWh/m², while the same unit with legal standard insulation would require 110 kWh/m². As the building was claimed to be sustainable on the basis of its outstanding energy saving performances, an ex post LCA was set up to understand whether, and to what extent, the positive judgement could be confirmed in a life cycle perspective. The dramatic contribution of materials-related impacts emerged. The shell-embedded materials represented the highest relative contribution, but maintenance operations also played a major role. The contributions of plants, building process and transportation were minor. The important role of the recycling potential also emerged. Unlike standard buildings, where heating-related impacts overshadow the rest of the life cycle, there is no single dominating item or aspect. Rather, several of them play equally important roles. The study has confirmed that the initial goal of environmental sustainability was reached, but to a much lower extent than previously thought. In comparison to a standard house, while the winter heat requirement was reduced by a ratio of 10:1, the life cycle energy was only reduced by 2.1:1 and the carbon footprint by 2.2:1.     

Polydimethylsiloxane crosslinking kinetics: A systematic study on Sylgard184 comparing rheological and thermal approaches

In this work a systematic investigation of crosslinking kinetics of Sylgard184 polydimethylsiloxane is performed in both isothermal and dynamic conditions. The results are discussed in terms of two conversions, α_C and α_R determined by thermal and rheological analysis, respectively. Thermal analysis can well detect the first stage of the reaction, while rheological analysis starts being sensitive only at longer time. However, once the rheological response is observable, it changes with time faster than the calorimetric one. From rheology experiments it comes out that the gel point occurs at α_R = 0.53, independently of the applied thermal history. At gel point, α_C is around 0.30 indicating that about 30% of the bonds involved in the crosslinking process is enough to create an infinite network. A modified version of the Kamal's autocatalytic model allows to fit and predict the experimental findings from both the techniques; however, two distinct sets of parameters have been used. The results of this work may be a useful tool to design appropriate curing cycles for the preparation of Sylgard184.     

Physical and mechanical properties of rock masses at Stromboli: a dataset for volcano instability evaluation

Stromboli island has a complex geological history with repeated changes in the volcanic activity alternating with destructive events, caldera collapses and flank landslides. The last activity resulted in the creation of the Sciara del Fuoco depression which was modified by the recent 2002–2003 landslide. The variation in lithology, degree of tectonization and disturbance has resulted in the presence of a wide spectrum of geotechnical materials. This paper summarises the physical and mechanical properties of Stromboli’s intact rocks, rock masses and loose deposits, based on field surveys and laboratory tests. A new classification of the rock succession is introduced and four lithotechnical units defined: Lava, Lava-Breccia, Breccia and Pyroclastic deposit. The range of variability in bulk volume, porosity, intact rock compressive strength and geological strength index is presented. The Hoek and Brown’s failure criterion was applied for each lithotechnical unit and the rock mass friction angle, apparent cohesion, tensile and compressive strength, global strength and modulus of deformation calculated in a specified stress range.      

Side chain porphyrin moiety linked to polymer-fullerene composite solar cell

This work investigates the photovoltaic properties of a BHJ solar cell made of an active layer constituted by phenyl-C₆₁-butyric acid methyl ester and a novel polyalkylthiophene derivative functionalized in the side chain with porphyrin dye. The polymer was fully characterized by FT-IR, NMR, UV–vis, GPC, DSC and TGA techniques and the active layer by cyclic voltammetry and AFM. The results of this study indicate that the solar cell made of polythiophene containing a 25% molar content of sensitizer dye as the active layer, exhibits higher power conversion efficiency, short circuit current and fill factor values than the reference cell based on polythiophene completely devoid of porphyrin.     

Cured products from different animal species

An assessment was made of the proximate composition, pH and a_W of raw beef, horsemeat and the meat of wild boar, deer and goat. The same assessment, together with one of fatty acids, cholesterol and free amino acids, was made of the same meats as cured products. The raw meat of the different animal species was found to have a reduced lipid, but high protein content. The cured meat of the horse and wild boar had low saturated fatty acid levels; the wild boar, goatmeat and beef were quantitatively similar with regard to monounsaturated fatty acids (MUFA) while in the horsemeat the polyunsaturated fatty acids (PUFA) were more raised, at an intermediate level in deer and extremely reduced in the beef final product. The cholesterol content in the cured product was markedly reduced in the horsemeat. The free amino acids content in the cured deer, wild boar and goat meat was more elevated, than in beef and horse cured meat.