Ressenyes

Obra ressenyada: Víctor SAMPEDRO BLANCO, Moviments socials: entre la lògica i les formes periodístiques. Movimientos sociales: debates sin mordaza. Desobediencia civil y servicio militar (1970-1996). Madrid: Centro de Estudios Constitucionales, 1997

Economic growth and atmospheric pollution in Spain: discussing the environmental Kuznets curve by hypothesis

The environmental Kuznets curve (EKC) hypothesis posits an inverted U relationship between environmental pressure and per capita income. Recent research has examined this hypothesis for different pollutants in different countries. Despite certain empirical evidence shows that some environmental pressures have diminished in developed countries, the hypothesis could not be generalized to the global relationship between economy and environment at all. In this article we contribute to this debate analyzing the trends of annual emission flux of six atmospheric pollutants in Spain. The study presents evidence that there is not any correlation between higher income level and smaller emissions, except for SO2 whose evolution might be compatible with the EKC hypothesis. The authors argue that the relationship between income level and diverse types of emissions depends on many factors. Thus it cannot be thought that economic growth, by itself, will solve environmental problems.Environmental Kuznets Curve, atmospheric pollution, Spain.

The use of rapid prototyping techniques (RPT) to manufacture micro channels suitable for high operation pressures and uPIV

This paper aims to present a new methodology to manufacture micro-channels suitable for high operating pressures and micro particle image velocimetry (µPIV) measurements using a rapid-prototyping high-resolution 3D printer. This methodology can fabricate channels down to 250 µm and withstand pressures of up to 5 ± 0.2 MPa. The manufacturing times are much shorter than in soft lithography processes. The novel manufacturing method developed takes advantage of the recently improved resolution in 3D printers to manufacture an rapid prototyping technique part that contains the hose connections and a micro-channel useful for microfluidics. A method to assemble one wall of the micro-channel using UV curable glue with a glass slide is presented – an operation required to prepare the channel for µPIV measurements. Once built, the micro-channel has been evaluated when working under pressure and the grease flow behavior in it has been measured using µPIV. Furthermore, the minimum achievable channels have been defined using a confocal microscopy study. This technique is much faster than previous micro-manufacturing techniques where different steps were needed to obtain the micro-machined parts. However, due to current 3D printers ' resolutions (around 50 µm) and according to the experimental results, channels smaller than 250-µm2 cross-section should not be used to characterize fluid flow behaviors, as inaccuracies in the channel boundaries can deeply affect the fluid flow behavior. The present methodology is developed due to the need to validate micro-channels using µPIV to lubricate critical components (bearings and gears) in wind turbines. This novel micro-manufacturing technique overcomes current techniques, as it requires less manufacturing steps and therefore it is faster and with less associated costs to manufacture micro-channels down to 250-µm2 cross-section that can withstand pressures higher than 5 MPa that can be used to characterize microfluidic flow behavior using µPIV.Peer ReviewedPostprint (author's final draft