Sistema electrónico de controlo de temperatura da água para aplicações domésticas

Este artigo descreve um sistema que permite controlar a temperatura e regular o caudal das águas sanitárias num ambiente doméstico. O sistema tem como limite sete saídas independentes de caudal, substituindo as tradicionais torneiras mecânicas e manuais. A arquitectura do sistema está dividida em dois tipos de blocos: a interface com o utilizador (IU) e o bloco de controlo e regulação (CR). A IU é composta por um mostrador e por um teclado que permitem a interacção do utilizador com o sistema. O bloco de CR é constituído por um circuito electrónico que gere os módulos da IU e o sistema electromecânico. No controlo de temperatura é usado um controlador PID digital. A regulação do caudal de cada saída é efectuada de forma independente.info:eu-repo/semantics/publishedVersio

Registador de dados para aplicações de baixo consumo

Este artigo descreve uma arquitectura de um registador de dados para aplicações de baixo consumo. São apresentados resultados experimentais sobre o desempenho do oscilador, que é um dos módulos do registador. São ainda apresentadas estimativas do consumo do registador e dos respectivos módulos. A autonomia e a estabilidade são os critérios de projecto mais relevantes de um registador de dados para aplicações de baixo consumo que exijam precisão temporal, por exemplo a sismologia oceânica.info:eu-repo/semantics/publishedVersio

The Coupled Aerosol and Tracer Transport model to the Brazilian developments on the Regional Atmospheric Modeling System (CATT-BRAMS) ? Part 1: Model description and evaluation

International audienceWe introduce the Coupled Aerosol and Tracer Transport model to the Brazilian developments on the Regional Atmospheric Modeling System (CATT-BRAMS). CATT-BRAMS is an on-line transport model fully consistent with the simulated atmospheric dynamics. Emission sources from biomass burning and urban-industrial-vehicular activities for trace gases and aerosol particles are obtained from several published datasets and remote sensing information. The tracer and aerosol mass concentration prognostic includes the effects of sub-grid scale turbulence in the planetary boundary layer, convective transport by shallow and deep moist convection, wet and dry deposition, and plume rise associated with vegetation fires in addition to the grid scale transport. The radiation parameterization takes into account the interaction between aerosol particles and short and long wave radiation. The atmospheric model BRAMS is based on the Regional Atmospheric Modeling System (RAMS), with several improvements associated with cumulus convection representation, soil moisture initialization and surface scheme tuned for the tropics, among others. In this paper the CATT-BRAMS model is used to simulate carbon monoxide and particulate material (PM2.5) surface fluxes and atmospheric transport during the 2002 LBA field campaigns, conducted during the transition from the dry to wet season in the southwest Amazon Basin. Model evaluation is addressed with comparisons between model results and near surface, radiosonde and airborne measurements performed during the field campaign, as well as remote sensing derived products. We show the matching of emissions strengths to observed carbon monoxide in the LBA campaign. A relatively good comparison to the MOPITT data, in spite of the fact that MOPITT a priori assumptions imply several difficulties, is also obtained

Using scale modelling to assess the prehistoric acoustics of stonehenge

With social rituals usually involving sound, an archaeological understanding of a site requires the acoustics to be assessed. This paper demonstrates how this can be done with acoustic scale models. Scale modelling is an established method in architectural acoustics, but it has not previously been applied to prehistoric monuments. The Stonehenge model described here allows the acoustics in the Late Neolithic and early Bronze Age to be quantified and the effects on musical sounds and speech to be inferred. It was found that the stone reflections create an average mid-frequency reverberation time of (0.64 ± 0.03) seconds and an amplification of (4.3 ± 0.9) dB for speech. The model has a more accurate representation of the prehistoric geometry, giving a reverberation time that is significantly greater than that measured in the current ruin and a full-size concrete replica at Maryhill, USA. The amplification could have aided speech communication and the reverberation improved musical sounds. How Stonehenge was used is much debated, but these results show that sounds were improved within the circle compared to outside. Stonehenge had different configurations, especially in terms of the positions of the bluestones. However, this made inaudible changes to the acoustics, suggesting sound is unlikely to be the underlying motivation for the various arrangements

A metric for predicting binaural speech intelligibility in stationary noise and competing speech maskers

One criterion in the design of binaural sound scenes in audio production is the extent to which the intended speech message is correctly understood. Object-based audio broadcasting systems have permitted sound editors to gain more access to the metadata (e.g., intensity and location) of each sound source, providing better control over speech intelligibility. The current study describes and evaluates a binaural distortion-weighted glimpse proportion metric -- BiDWGP -- which is motivated by better-ear glimpsing and binaural masking level differences. BiDWGP predicts intelligibility from two alternative input forms: either binaural recordings or monophonic recordings from each sound source along with their locations. Two listening experiments were performed with stationary noise and competing speech, one in the presence of a single masker, the other with multiple maskers, for a variety of spatial configurations. Overall, BiDWGP with both input forms predicts listener keyword scores with correlations of 0.95 and 0.91 for single- and multi-masker conditions, respectively. When considering masker type separately, correlations rise to 0.95 and above for both types of maskers. Predictions using the two input forms are very similar, suggesting that BiDWGP can be applied to the design of sound scenes where only individual sound sources and their locations are available

Perception and automatic detection of wind-induced microphone noise

Wind can induce noise on microphones, causing problems for users of hearing aids and for those making recordings outdoors. Perceptual tests in the laboratory and via the Internet were carried out to understand what features of wind noise are important to the perceived audio quality of speech recordings. The average A-weighted sound pressure level of the wind noise was found to dominate the perceived degradation of quality, while gustiness was mostly unimportant. Large degradations in quality were observed when the signal to noise ratio was lower than about 15 09dB. A model to allow an estimation of wind noise level was developed using an ensemble of decision trees. The model was designed to work with a single microphone in the presence of a variety of foreground sounds. The model outputted four classes of wind noise: none, low, medium, and high. Wind free examples were accurately identified in 79% of cases. For the three classes with noise present, on average 93% of samples were correctly assigned. A second ensemble of decision trees was used to estimate the signal to noise ratio and thereby infer the perceived degradation caused by wind noise

Simulaçao numérica da dispersao de poluentes emitidos por incendios no verao de 2003 na Peninsula Ibérica

Ponencia presentada en: XXIX Jornadas Científicas de la AME y el VII Encuentro Hispano Luso de Meteorología celebrado en Pamplona, del 24 al 26 de abril de 2006.[PT]O objectivo deste trabalho é utilizar o modelo CATT-B-RAMS (Coupled Aerosol and Tracers Transport model to the Brazilian Regional Atmospheric Modeling System) para estudar o transporte atmosférico do monóxido de carbono (CO) e material particulado (PM2.5) emitidos por queimadas que ocorreram durante o Verão de 2003 na Península Ibérica, no período de 31 de Julho a 3 de Agosto com a situação sinóptica actuante na exportação destes poluentes. As simulações numéricas foram feitas com a assimilação dos dados de fogos derivados a partir de medidas do MODIS/AQUA para a Europa para implementar a posição da emissão. Para a caracterização do estado inicial do modelo foram usadas as análises do modelo global AVN/NCEP (Aviation run of the National Center for Environmental Prediction Global Spectral Model) com grade de resolução de 80 km. Os resultados indicam que o modelo de mesoescala pode ser uma boa ferramenta para descrever a circulação atmosférica reproduzindo as principais características da situação sinóptica e o entendimento e avaliação deste impacto, passam necessariamente, pela junção de estudos observacionais e modelação numérica gerando modelos complexos que descrevam as inter-relações biosfera-atmosfera, caracterizando um estudo multidisciplinar.[EN]This study presents the transport of gases and particulate emitted by large scale vegetation fires that took place in the Iberian Peninsula in summer of 2003. This study is carried out through a numerical simulation using a highresolution configuration of the 3-D transport model CATT-BRAMS (Coupled Aerosol and Tracer Transport to the Brazilian developments on the Regional Atmospheric Modeling System) coupled to a biomass burning emission model. The sources emission from biomass burning for carbon monoxide (CO) and particulate material (PM2.5) are defined using MODIS/TERRA fire product and local observations. The initial and lateral boundary conditions necessary to drive model were provided by the Aviation run of the National Center for Environmental Prediction Global Spectral Model (AVN/NCEP). The coarse grid resolution was defined with 80 km grid spacing. The results show that the mesoscale model can be used as a useful tool to describe the atmospheric circulation reproducing the main characteristics of the synoptic situation and how it controls the pollution transport

Muddy, muddled, or muffled? Understanding the perception of audio quality in music by hearing aid users

Introduction: Previous work on audio quality evaluation has demonstrated a developing convergence of the key perceptual attributes underlying judgments of quality, such as timbral, spatial and technical attributes. However, across existing research there remains a limited understanding of the crucial perceptual attributes that inform audio quality evaluation for people with hearing loss, and those who use hearing aids. This is especially the case with music, given the unique problems it presents in contrast to human speech. Method: This paper presents a sensory evaluation study utilising descriptive analysis methods, in which a panel of hearing aid users collaborated, through consensus, to identify the most important perceptual attributes of music audio quality and developed a series of rating scales for future listening tests. Participants (N = 12), with a hearing loss ranging from mild to severe, first completed an online elicitation task, providing single-word terms to describe the audio quality of original and processed music samples; this was completed twice by each participant, once with hearing aids, and once without. Participants were then guided in discussing these raw terms across three focus groups, in which they reduced the term space, identified important perceptual groupings of terms, and developed perceptual attributes from these groups (including rating scales and definitions for each). Results: Findings show that there were seven key perceptual dimensions underlying music audio quality (clarity, harshness, distortion, spaciousness, treble strength, middle strength, and bass strength), alongside a music audio quality attribute and possible alternative frequency balance attributes. Discussion: We outline how these perceptual attributes align with extant literature, how attribute rating instruments might be used in future work, and the importance of better understanding the music listening difficulties of people with varied profiles of hearing loss