Surface treatment with UV-ozone to improve adhesion of vulcanized rubber formulated with an excess of processing oil

An excess of processing oil was intentionally added in the formulation of vulcanized styrene-butadiene rubber for analyzing the effect on the treatment with UV radiation combined with ozone (UV-ozone) in improving the adhesion to waterborne polyurethane adhesive in footwear. Due to the excess of processing oil in the rubber, poor adhesion was expected. Both the length of the treatment and the distance between the UV radiation source to the rubber surface were studied, and the effects of the treatment on the surface chemistry, wettability and surface energy, and topography of the rubber were analyzed. The treatment of the rubber with UV-ozone removed hydrocarbon moieties and zinc stearate from the surface, and surface oxidation (C-O, C=O and COO- groups formation) occurred. As a consequence, improved wettability and increased surface energy (mainly due to the polar component of the surface energy) were obtained. The increase in the length of treatment and for a distance of 3–5 cm from the rubber to the UV radiation source favored the effectiveness of the UV-ozone treatment. Besides, whereas the UV-ozone treatment for 3 min produced the ablation of surface contaminants mainly, longer lengths of treatment (i.e., 6–9 min) caused roughness and cracks on the rubber surface. The UV-ozone treatment also caused heating of the surface. Finally, the treatment with UV-ozone increased the adhesion of the rubber to waterborne polyurethane adhesive, the highest adhesion was obtained in the joints made with UV-ozone treated rubber for 3 and 6 min at a UV radiation source-rubber surface distance of 5 cm

Viscoelastic and adhesion properties of hot-melts made with blends of ethylene-co-n-butyl acrylate (EBA) and ethylene-co-vinyl acetate (EVA) copolymers

Several hot-melts (HMAs) were prepared by using blends of ethylene-co-n-butyl acrylate (EBA) and ethylene-co-vinyl acetate (EVA) copolymers - EBA/EVA. HMAs were prepared with mixtures of EVA copolymers with 18 (EVA18) and 27 (EVA27) wt% vinyl acetate contents and EBA copolymer with 27 wt% n-butyl acrylate, polyterpene resin and mixture of microcrystalline and Fischer-Tropsch waxes. HMAs made with EBA/EVA blends showed lower viscosities and reduced shear thinning than the ones made with EBA or EVA due to differences in compatibility, but both the set time and the open time were not affected as they depended mainly on the wax nature and amount. The increase of the vinyl acetate (VA) content in EVA copolymer reduced the crystallinity of the EBA/EVA blends. Even EBA copolymer was more compatible with EVA27 than with EVA18 (the α- and β-transitions shown in DMTA plots were closer) and the compatibility did not vary with the EBA content in the blends. The addition of polyterpene resin and the mixture of waxes decreased the compatibility of the EBA/EVA blends, the higher compatibility was observed for the HMAs made with only one copolymer. The tack of the HMAs depended on their EBA/EVA contents, EBA/EVA27 HMAs showed broader temperature interval with higher tack, while the tack of EBA/EVA18 HMAs blend decreased and the temperature interval with tack was shortened and shifted to lower temperatures. Adhesion to polypropylene film was improved in HMAs made with 75 wt% EBA/25 wt% EVA18 and 50–75 wt% EBA/50-25 wt% EVA27. The adhesion to aluminum film of EBA or EVA hot melts was improved only in the joints made with EBA/EVA 27 HMAs, more noticeably when they contained higher EBA content.Financial support by Technology and New Ventures Department of Repsol S.A. (Madrid, Spain) (grant no. REPSOL5-12I) is acknowledged

Basic actions to reduce dropout rates in distance learning

Today’s society, which is strongly based on knowledge and interaction with information, has a key component in technological innovation, a fundamental tool for the development of the current teaching methodologies. Nowadays, there are a lot of online resources, such as MOOCs (Massive Open Online Courses) and distance learning courses. One aspect that is common to all of these is a high dropout rate: about 90% in MOOCs and 50% in the courses of the Spanish National Distance Education University, among other examples. In this paper, we analyze a number of actions undertaken in the Master’s Degree in Computational Mathematics at Universitat Jaume I in Castellón, Spain. These actions seem to help decrease the dropout rate in distance learning; the available data confirm their effectiveness

The color of olive oils: The pigments and their likely health benefits and visual and instrumental methods of analysis

The color of olive oils, and of foods in general, can influence consumer choices to a large extent and can be related to the processing treatments they have undergone. Olive oil color is due to 2 types of pigments, chlorophylls and carotenoids, which are attracting the attention of the scientific community due to the probable health benefits they can provide. Appropriate methodologies for the meaningful definition of the color of olive oil are there-fore necessary for various reasons. In this review, we discuss the importance of olive oil color and the applicable legislation and regulation, including sections devoted to the pigments accounting for the growing importance as likely health-promoting substances. Furthermore, we review in depth the different approaches (visual and instrumental methods) used for color measurements in the last 50 y. Instrumental methods have been shown to be highly appropriate for objective assessments and also for the rapid determination of the pigments

Molino pulverizador dual

This project is based on an improvement to be made in the hammer mills used in the industry. After analyzing and seeing how tedious it is to constantly change sieves to obtain two different grain sizes, we devised a way to obtain the same result without doing any type of clearing, using a system of gates that allow the passage of the crushed product. made one sieve or another.Este proyecto se fundamenta en una mejora a realizar en los molinos de martillo utilizados en la industria. Luego de analizar y ver lo tedioso que es realizar constantemente el cambio de cribas para obtener dos diferentes tamaños de grano, ideamos la forma de obtener el mismo resultado sin hacer ningún tipo de desmonte, utilizando un sistema de compuertas que permitan el paso del producto triturado hacía una criba u otra.&nbsp

Aprendizaje cooperativo y Flipped Classroom

Postprint (published version

El lío de las siglas

Postprint (published version

Proyecto transversal en los estudios de Ingeniería Electrónica Industrial y Automática

Postprint (published version

Catchment areas of high-speed rail stations: a model based on spatial analysis using ridership surveys

This paper focuses on the spatial influence of High-Speed Rail stations, based on the notion of catchment area. Given the features of High-Speed Rail, its operations can and must serve a role beyond the station and the city in which it is located. Using a spatial systemic approach, this paper proposes a method to analyse the factors that may affect the size and shape of the catchment areas according to the relationship between distance and ridership. This study employs data from surveys of six stations of the Spanish high-speed rail system to apply the model and demonstrates that the context is crucial for regional use. The outcome also proves that other relevant factors should be considered in addition to the network to extend the use of highspeed services and increase its profits, which is a potential approach for future research

HR management during lean production adoption

This paper aims to identify the success factors linked to human resources management during the lean production (LP) adoption process. A model of these factors and their interrelationships is also to be built to understand the sequence that leads to the cultural change required in lean production adoption. A case study is carried out in selected same-industry companies that are on the same level in the supply chain and have recently completed LP adoption. Twelve first-tier production plants in the aeronautics industry were selected. Data were gathered from interviews with plant managers and the people in charge of LP in the plant. Data were analyzed using open and coaxial coding and triangulation both within cases and across cases. The results highlight a number of success factors that depend on the phase of the LP adoption process. In the phase prior to adoption, the success factors are the incorporation of external change agents and the management averting inertia, whereas in the other phases of the adoption process five main factors were found: training, communication, rewards, job design and work organization. The findings stress the importance of human resources being managed appropriately during LP adoption for LP to be accepted and adapted. There are a number of key aspects related to human resource management that should be taken into account during each of the phases that occur during the LP adoption process. Further developments include measuring the intensity of the relationships identified and combining qualitative and quantitative methodologies simultaneously to overcome problems with the limited generalization of the results. Practitioners in charge of LP adoption must be mindful of the key human resource management-related aspects before and during the LP adoption process and the guidelines to be followed in each of these aspects for the outcomes of LP to be achieved and maintained