Computational analysis of fire dynamics inside a wind turbine

Wind turbines are generally considered cost-effective, reliable and sustainable energy sources. Fires are not common in wind turbines, but a significant number of fires occur every year due to the large number of turbines installed. Wind turbine fires are difficult to extinguish hence significant damage is expected. Due to the unmanned operation, the probability of a turbine being occupied during a fire is very low. However, operators can do several tasks every week, and hence be exposed to a certain risk. Moreover, there is a general lack of information about how a fire develops inside a wind turbine and the subsequent evolution of the tenability conditions during the time required for an eventual evacuation. Gamesa has been working on fire safety since 2013, using CFD fire modelling to provide insights on wind turbine fire development for the design of emergency procedures. The paper describes a fire hazard analysis performed in a Gamesa’s 2.5 MW turbine. A CFD simulation is carried out to estimate the effects during the first minutes of a typical wind turbine fire in an electrical cabinet. Results show that average oxygen concentration at the nacelle remains above 19.5% during the first 10 min; temperature remains below 60°C for 12 min if measured at 1.5 m; and visibility is on average assured at heights lower than 1.5 m, with values above 5 m during the first 8 min in worse locations, implying no danger for personnel. The potential of this type of analysis to design safer wind turbines under performance-based approaches is clearly demonstrated.Peer ReviewedPostprint (author's final draft

Focusing the HIV response through estimating the major modes of HIV transmission:a multi-country analysis

Objective An increasing number of countries have been estimating the distribution of new adult HIV infections by modes of transmission (MOT) to help prioritise prevention efforts. We compare results from studies conducted between 2008 and 2012 and discuss their use for planning and responding to the HIV epidemic. Methods The UNAIDS recommended MOT model helps countries to estimate the proportion of new HIV infections that occur through key transmission modes including sex work, injecting drug use (IDU), men having sex with men (MSM), multiple sexual partnerships, stable relationships and medical interventions. The model typically forms part of a country-led process that includes a comprehensive review of epidemiological data. Recent revisions to the model are described. Results Modelling results from 25 countries show large variation between and within regions. In sub-Saharan Africa, new infections occur largely in the general heterosexual population because of multiple partnerships or in stable discordant relationships, while sex work contributes significantly to new infections in West Africa. IDU and sex work are the main contributors to new infections in the Middle East and North Africa, with MSM the main contributor in Latin America. Patterns vary substantially between countries in Eastern Europe and Asia in terms of the relative contribution of sex work, MSM, IDU and spousal transmission. Conclusions The MOT modelling results, comprehensive review and critical assessment of data in a country can contribute to a more strategically focused HIV response. To strengthen this type of research, improved epidemiological and behavioural data by risk population are needed

Discriminating criteria of Pyrenean Arties marble (Aran Valley, Catalonia) from Saint-Béat marbles: Evidence of Roman use

The “Val d’Aran” is a valley situated on the Atlantic sideof the Pyrenees. Located in the northwest corner of Cat-alonia, has easy connection with France by the course ofthe Garonne River, which forms the main communica-tion route, flows over land Aquitaine and empties intothe Atlantic Ocean near Bordeaux. Under Roman con-trol, the Aran Valley was part of the Novempopulaniaprovince.Five of the most significant archaeological artefactsfound in the Valley have been analyzed to investigatethe provenance of the marble used for their manufac-ture. These archaeological pieces dated from 2ndto 5thcentury AD, are currently deposited in the “Musèu deraVal d’Aran”. A combination of techniques with OpticalMicroscopy, Cathodoluminescence (CL) and Isotope-Ratio Mass Spectrometry was applied to know theirmarble source.To carry out the comparative study with quarry mar-bles, local outcrops were examined and sampled. Mar-bles from the quarry of Arties were specially taken intoaccount since, at least from the medieval times, wereused with building purposes. The nearby Roman quar-ries of Saint-Béat have also been taken into considera-tion. The analytical results after applying the samemethodology to both marble samples, artefacts andquarries, allow differentiating the two marble sources,Arties and Saint-Bé

Invasive pneumococcal disease among children in a health district of Barcelona: early impact of pneumococcal conjugate vaccine

ABSTRACTThis study evaluated the impact of heptavalent pneumococcal conjugate vaccine (HPCV) on invasive pneumococcal disease (IPD) in children aged ≤ 5 years in Barcelona, Spain. The incidence of IPD, vaccine uptake and prevalence of nasopharyngeal colonisation were analysed in two different periods: 1999–2001 (pre-licence period), and 2002–2004 (post-licence period). In total, 121 cases of IPD were identified. The overall incidence of IPD decreased from 96.9 cases/100 000 to 90.6 cases/100 000 (OR 0.93, 95% CI 0.69–1.26, p 0.71) between the two periods. The proportion of cases caused by non-vaccine-related serotypes (NVS) increased from 21% to 43.7% (OR 2.9, 95% CI 1.2–7, p 0.01). IPD was diagnosed in seven vaccinated children, six of whom were infected by NVS. There was a trend of diminishing prevalence of resistance to penicillin and macrolides in 2002–2004. The incidence of empyema increased from 1.7 to 8.5/100 000 (OR 4.5, 95% CI 0.91–18, p 0.06). The rate of vaccination ranged from 4.8% to 34%. It was concluded that the rates of IPD in this area did not decrease following the introduction of HPCV. The low uptake of vaccine and the greater proportion of colonisation/infection by NVS probably explain these findings. A trend of increasing empyema was also apparent. A decrease in the prevalence of penicillin and macrolide resistance paralleled the progressive uptake of vaccine