María González

Applications of FTIR on Epoxy Resins - Identification, Monitoring the Curing Process, Phase Separation and Water Uptake

Epoxy resins are a family of thermosetting materials widely used as adhesives, coatings and matrices in polymer composites because of the low viscosity of the formulations, good insulating properties of the final material even at high temperatures and good chemical and thermal resistance (May, 1988). Epoxy thermosets can be described as 3D polymer networks formed by the chemical reaction between monomers (“curing”). This 3D covalent network structure determines the properties of thermosetting polymers: unlike thermoplastics, this kind of polymers does not melt, and once the network has been formed the material cannot be reprocessed. Maybe one of the main advantages of epoxy thermosets is that the starting monomers have low viscosity so that complex geometries can be easily shaped and fixed after curing the monomers. Thus the formation of the network via chemical reaction is a key aspect in this kind of materials.

High porosity scaffold composites of graphene and carbon nanotubes as microwave absorbing materials

The design of microwave absorbing materials requires low reflection and high absorption of radiation simultaneously. Low reflection of electromagnetic waves can be achieved inducing porous faces which minimize the impedance mismatch. High absorption can be obtained by increasing the conductivity of the material. We report the preparation of highly porous scaffolds from a combination of graphene and carbon nanotubes. The bimodal porous structure was controlled making use of the surface properties of graphene oxide that are able to stabilize hexane droplets in aqueous dispersions of graphene oxide and carbon nanotubes. After hydrothermal and two step freeze-drying processes, macro- (220 microns) and mesoporous (10 microns) structures, due to hexane droplets and freeze drying, respectively, were obtained. DC conductivities of 8.2, 14.7, 33.2, and 60.7 S m−1 were obtained for graphene scaffolds containing 0, 10, 20 and 40% of carbon nanotubes respectively. An electromagnetic characterization was performed on scaffolds infiltrated with epoxy resin; using appropriate models, the electromagnetic properties of the conducting phase have been obtained. Scaffolds with a thickness of 9 mm were able to absorb up to 80% of the incident radiation keeping the reflection as low as 20%.

A study of accessibility requirements for media players on the web

Multimedia content covers the Web, and we should provide access to all people. For this reason, we must consider including accessibility requirements in a synchronized manner with the alternative resources such as caption and audio description among others. In addition, it is very important to take into account accessibility requirements in the player to avoid barriers and to ensure access to this multimedia content as well as their resources. This paper presents an overall study on standards and players with accessibility requirements. Moreover, solutions to improve the accessibility features in the YouTube player are presented. Based on this study, we have distinguished a set of guidelines to take into account for including accessibility requirements in players. Furthermore, we suggest an agile evaluation process which indicates the order of accessibility guidelines to check. Finally, the proposed evaluation method is put into practice with a case study: accessibility features are evaluated in three widely used players.

Web accessibility requirements for media players

Video Content continues to strenghten on the Web, because of that fact, it is neccessary to include video content with suitable accessibility requirements to be used by all people. User Agent (such as player, browser), also have to include accessibility requirements. In this paper a set of basic guidelines is included for professionals who want to embed video players on their Web.

Approach design of an accessible media player

Abstract The increase in rich and interactive content on the Web, such as video and audio, has brought about a growth in the number and type of users that access it. This means that this content should be accessible to anyone, including people with disabilities. Therefore, it should be accompanied by media alternatives (captions, audio description, sign language, extended audio description, etc.), which should be handled by an accessible user agent that provides support for them. This paper presents: (1) an approach with accessibility requirements following standards to include accessibility in a user agent for delivering accessible multimedia content based on it, (2) a conceptualization of these requirements that provides an abstract user interface which may be integrated into the development process, after that, (3) a check of the integration of the accessibility requirements in the models, and (4) finally, some lessons learned and conclusions are shown.

HTML 5 support for an accessible user-video-interaction on the web

Multimedia content covers the Web, and we should provide access to all people. For this reason, it is very important to take into account accessibility requirements in the player to avoid barriers and to ensure access to this multimedia content as well as their resources. One of the most frequent barriers is the technological obstacle: the necessity for the user to install the required plug-ins in to order to access video. The new standard HTML5 provides a solution to this problem. However, it does not fully support accessibility requirements of W3C standards, including WCAG and interaction requirement of UAAG. This paper1 introduces an overall study of this new standard in relation to accessibility requirements for the players as well as an accessible HTML5 Media Player.

An Approach to user Interface Design of an Accessible user Agent

The increase in rich and interactive content on the web has allowed the growth of the number and type of users that access them. This implies that such content should be accessible to anyone, including people with disabilities. Therefore, it should be accompanied with media alternatives (captions, audio description), which should be handled by an accessible user agent that provides support for them. This paper presents: 1) an approach with accessibility requirements following standards to include accessibility in a user agent for delivering accessible multimedia content, and based on it, 2) a conceptualization that provides an abstract user interface model with the ability to be integrated into the development process.

An illustrated methodology for evaluating ASR systems

Automatic speech recognition technology can be integrated in an information retrieval process to allow searching on multimedia contents. But, in order to assure an adequate retrieval performance is necessary to state the quality of the recognition phase, especially in speaker-independent and domainindependent environments. This paper introduces a methodology to accomplish the evaluation of different speech recognition systems in several scenarios considering also the creation of new corpora of different types (broadcast news, interviews, etc.), especially in other languages apart from English that are not widely addressed in speech community.