A simple model to describe the thixotropic behavior of paints.

We propose a simple rheological model to describe the thixotropic behavior of paints, since the classical hysteresis area, which is usually used, is not enough to evaluate thixotropy. The model is based on the assumption that viscosity is a direct measure of the structural level of the paint. The model depends on two equations: the Cross-Carreau equation to describe the equilibrium viscosity and a second order kinetic equation to express the time dependence of viscosity. Two characteristic thixotropic times are differentiated: one for the net structure breakdown, which is defined as a power law function of shear rate, and an other for the net structure buildup, which is not dependent on the shear rate. The knowledge of both kinetic processes can be used to improve the quality and applicability of paints. Five representative commercial protective marine paints are tested. They are based on chlorinated rubber, acrylic, alkyd, vinyl, and epoxy resins. The temperature dependence of the rheological behavior is also studied with the temperature ranging from 5 ºC to 35 ºC. It is found that the paints exhibit both shear thinning and thixotropic behavior. The model fits satisfactorily the thixotropy of the studied paints. It is also able to predict the thixotropy dependence on temperature. Both viscosity and the degree of thixotropy increase as the temperature decreases.

Responses to a crisis: FASA-Renault in Spain during the 1970s

[cat] Aquest treball analitza la trajectòria de l’empresa FASA-Renault durant la dècada dels setanta del segle XX. Aquest període compren els primers anys de la crisis experimentada per l’economia i la industria espanyola entre 1974 y 1985. A nivell extern, l’economia espanyola es va veure afectada per dos xocs en el preu del petroli. A nivell intern, la industria de l’automòbil es va veure afectat per un decret governamental: es tractava de l’anomenat decret “Ford”, aprovat l’any 1972, el qual facilitava l’establiment de Ford a Espanya. Aquest decret va tenir greus conseqüències per a SEAT, el principal productor espanyol. Entre 1972 y 1980 la producció de SEAT es va reduir en una tercera part i la seva situació financera va esdevenir insostenible. Per contra, en aquest període FASA-Renault va esdevenir el principal productor ubicat a Espanya (la seva producció es va multiplicar per 3,5 durant els anys setanta) i en líder de ventes en el mercat espanyol (la seva penetració es va incrementar del 23 al 36%). El principal objectiu del treball es analitzar els factor que expliquen l’èxit de FASARenault durant els anys setanta.

Responses to a crisis: FASA-Renault in Spain during the 1970s

[cat] Aquest treball analitza la trajectòria de l’empresa FASA-Renault durant la dècada dels setanta del segle XX. Aquest període compren els primers anys de la crisis experimentada per l’economia i la industria espanyola entre 1974 y 1985. A nivell extern, l’economia espanyola es va veure afectada per dos xocs en el preu del petroli. A nivell intern, la industria de l’automòbil es va veure afectat per un decret governamental: es tractava de l’anomenat decret “Ford”, aprovat l’any 1972, el qual facilitava l’establiment de Ford a Espanya. Aquest decret va tenir greus conseqüències per a SEAT, el principal productor espanyol. Entre 1972 y 1980 la producció de SEAT es va reduir en una tercera part i la seva situació financera va esdevenir insostenible. Per contra, en aquest període FASA-Renault va esdevenir el principal productor ubicat a Espanya (la seva producció es va multiplicar per 3,5 durant els anys setanta) i en líder de ventes en el mercat espanyol (la seva penetració es va incrementar del 23 al 36%). El principal objectiu del treball es analitzar els factor que expliquen l’èxit de FASARenault durant els anys setanta.

From Educational Segregation to Transformative Inclusion

Recent studies conducted in Europe using communicative methodology highlight that different ways of grouping students has a direct effect on their academic output. This article analyzes how said research methodology identifies and analyzes those student groupings that provide greater academic success and improve classroom coexistence at Spanish educational centers. Said methodology entails all of the research participants researchers, teachers, families, and students reflecting on the consequences of streaming, mixture, and inclusion for student academic achievement. Following this, our conclusions are compared with the policies and educational practices implemented in Spanish schools, which are not based on scientific knowledge and do not usually lead to academic success. Finally, recommendations are presented for future educational policies with the aim of providing an alternative for teachers and educational managers that would substantially improve student academic success.

What are the success factors for Spanish textile firms? An exploratory multiple-case study

The objective of this article is to identify differential traits of successful SMEs in comparison to average SME firms in the textile and clothing sector. The method used is the multiple case-study of 12 firms based on qualitative and quantitative data obtained by means of in-depth interviews. Building on recent academic literature, we use four main dimensions that may explain success: i) knowledge generation (R&D) and acquisition; ii) innovation activity; iii) product and market characteristics and iv) strategic characteristics. Our results indicate that a higher R&D intensity and knowledge acquisition do not explain success. The main differential characteristic is that successful firms have a higher level of innovation activity, since innovation is their strategic priority, being a result of perceiving the key success factors of their markets differently. From the analysis it also follows that the prevalent strategy of successful firms is the niche strategy, with a demand pull focus, and a high proximity to the customer

Shaping urban traffic patterns through congestion charging : What factors drive success or failure?

Congestion costs are emerging as one of the most important challenges faced by metropolitan planners and transport authorities in first world economies. In US these costs were as high as 78 million dollars in 2005 and are growing due to fast increases in travel delays. In order to solve the current and severe levels of congestion the US department of transportation have recently started a program to initiate congestion pricing in five metropolitan areas. In this context it is important to determine those factors helping its implementation and success, but also the problems or difficulties associated with charging projects. In this article we analyze worldwide experiences with urban road charging in order to extract interesting and helpful lessons for policy makers engaged in congestion pricing projects and for those interested in the introduction of traffic management tools to regulate the entrance to big cities.

Advancing towards inclusive social research: visual methods as opportunities for people with severe mental illness to participate in research

This article explores the possibilities offered by visual methods in the move towards inclusive research, reviewing some methodological implications of said research and reflecting on the potential of visual methods to meet these methodological requirements. A study into the impact of work on social inclusion and the social relationships of people suffering from severe mental illness (SMI) serves to illustrate the use of visual methods such as photo elicitation and graphic elicitation in the context of in-depth interviews with the aim of improving the aforementioned target group’s participation in research, participation understood as one of the basic elements of inclusive approaches. On the basis of this study, we reflect on the potential of visual methods to improve the inclusive approach to research and conclude that these methods are open and flexible in awarding participantsa voice, allowingpeople with SMI to express their needs, and therefore adding value to said approach