Dielmo 3D Viewer based on NASA World Wind

Partiendo de la versión Java del software libre NASA World Wind, DIELMO ha desarrollado el software Dielmo 3D Viewer que permite la creación de escenarios virutales en 3D que se convierten en clientes IDE y que permiten un mejor conocimiento del territorio, tratando la tercera dimensión con el máximo rigor

Evaluating the performance of external fault ridethrough solutions used in wind farms with fixed speed induction generators when facing unbalanced faults

Na sequência da integração da energia eólica em larga escala foram estabelecidos códigos de rede pelos vários operadores de sistema, exigindo que os parques eólicos permaneçam em serviço durante e após a ocorrência de defeitos na rede a montante. Nos parques eólicos equipados com sistemas de velocidade constante este requisito pode ser assegurado pela instalação, no ponto de interligação à rede, de equipamento de compensação dinâmica de potência reactiva, controlado como fonte de tensão, sendo as funções de controlo baseadas em medidas efectuadas no ponto de interligação relativamente às componentes directas da tensão e da corrente. Como a adopção deste tipo de soluções externas é adequada ao funcionamento do sistema em regime equilibrado, este artigo foca a avaliação do desempenho da solução no caso da ocorrência de defeitos assimétricos. Os resultados obtidos através das simulações dinâmicas evidenciam o aparecimento de sobre tensões nas fases não afectadas pelo defeito que poderão colocar o parque eólico fora de serviço.

Are there hazardous auditory effects of high-frequency turbines and ultrasonic dental scalers on dental professionals?

The purpose of this pilot study was to survey dentists in the St. Louis area to assess their subjective opinion of commonly used dental handpieces as well as history of noise exposure and use of hearing protection. Selected handpieces were then chosen to measure their output levels and determine if emissions are hazardous to the auditory system.

Wind-tunnel modelling of dispersion from a scalar area source in urban-like roughness

A wind-tunnel study was conducted to investigate ventilation of scalars from urban-like geometries at neighbourhood scale by exploring two different geometries a uniform height roughness and a non-uniform height roughness, both with an equal plan and frontal density of λ p = λ f = 25%. In both configurations a sub-unit of the idealized urban surface was coated with a thin layer of naphthalene to represent area sources. The naphthalene sublimation method was used to measure directly total area-averaged transport of scalars out of the complex geometries. At the same time, naphthalene vapour concentrations controlled by the turbulent fluxes were detected using a fast Flame Ionisation Detection (FID) technique. This paper describes the novel use of a naphthalene coated surface as an area source in dispersion studies. Particular emphasis was also given to testing whether the concentration measurements were independent of Reynolds number. For low wind speeds, transfer from the naphthalene surface is determined by a combination of forced and natural convection. Compared with a propane point source release, a 25% higher free stream velocity was needed for the naphthalene area source to yield Reynolds-number-independent concentration fields. Ventilation transfer coefficients w T /U derived from the naphthalene sublimation method showed that, whilst there was enhanced vertical momentum exchange due to obstacle height variability, advection was reduced and dispersion from the source area was not enhanced. Thus, the height variability of a canopy is an important parameter when generalising urban dispersion. Fine resolution concentration measurements in the canopy showed the effect of height variability on dispersion at street scale. Rapid vertical transport in the wake of individual high-rise obstacles was found to generate elevated point-like sources. A Gaussian plume model was used to analyse differences in the downstream plumes. Intensified lateral and vertical plume spread and plume dilution with height was found for the non-uniform height roughness