Ventilação e prescrições urbanísticas: uma aplicação simulada para a Orla da Praia do Meio em Natal/RN

This work analyses a study on natural ventilation and its relation to the urban legislation versus the building types in an urban fraction of coastal area of Praia do Meio in the city of Natal/RN, approaching the type or types of land use most appropriate to this limited urban fraction. The objective of this study is to analyse the effects of the present legislation as well as the types of buildings in this area on the natural ventilation. This urban fraction was selected because it is one of the sites from where the wind flows into the city of Natal. This research is based on the hypothesis stating that the reduction on the porosity of the urban soil (decrease in the set back/boundary clearance), and an increase in the form (height of the buildings) rise the level of the ventilation gradient, consequently causing a reduction on the wind speed at the lowest part of the buildings. Three-dimensional computational models were used to produce the modes of occupation allowed in the urban fraction within the area under study. A Computational Fluid Dynamics (CFD) software was also used to analyse the modes of land occupation. Following simulation, a statistical assessment was carried out for validation of the hypothesis. It was concluded that the reduction in the soil porosity as a consequence of the rates that defined the minimum boundary clearance between the building and the boundary of the plot (and consequently the set back), as well as the increase in the building form (height of the buildings) caused a reduction in the wind speed, thus creating heat islands

Análise bioclimática e investigação do conforto térmico em ambientes externos: uma experiência no bairro de Petrópolis em Natal/RN

This study was intended to investigate how the urban form has been influencing the changes in the climate of the city and make a correlation between the climate and the thermal sensation of the users of open spaces. The research was developed in the district of Petrópolis in Natal/ RN whose occupation has been almost consolidated. Among other reasons, this district was selected because it was planned considering the environmental aspects of comfort. The methodologies used are based on KATZSCHNER (1997) and OLIVEIRA (1988) studies, which suggest the drawing and analysis of maps of the area under study, including topography, height of the buildings, land use, green areas, and types of soil pavement, as well as measurement of the environmental variables: air temperature, relative humidity, direction and wind speed for a comparative study. As part of this, study local users of the district were interviewed about their thermal sensations in open spaces. For the statistical analysis, data was collected at 10 distinct points characterized by BUSTOS ROMERO (2002), being 8 within the district and 2 at different places (outside the district), at climatologic stations, in 3 periods (August/2000, January/2002 and June/2002), for 4 consecutive days for each measurement (from Sunday to Wednesday) at the time of lower and higher temperatures in the city, 6:00 am and 1:00 pm, respectively. At the same time interviews were carried out with users of the open spaces in the area, totaling 171 valid formularies. The urban form showed a rather leveled topography, great diversity of land use and height of the buildings, with the existence of an area mostly occupied with high buildings, very little green area and soil practically impermeable. The statistical analysis showed high temperature and humidity levels. The wind direction is predominantly Southeast with extremely variable speeds. When the data from this district is compared with the data from other areas in the city and its outskirt, it was observed that this district is hotter and less ventilated than the others; besides, most users said that they felt uncomfortable in the local environmental conditions. The results of the analysis generated a zoning for the district with recommendations for soil occupation. The profile of the user was defined regarding the thermal comfort, as well as some discussion about the comfort parameters, including the proposal of limiting areas of temperature and humidity for the thermal comfort in the open spaces

Controle automático para injeção otimizada de gás em poços de petróleo equipados para funcionamento com gás lift contínuo

The continuous gas lift method is the main artificial lifting method used in the oil industry for submarine wells, due to its robustness and the large range of flow rate that the well might operate. Nowadays, there is a huge amount of wells producing under this mechanism. This method of elevation has a slow dynamics due to the transients and a correlation between the injected gas rate and the of produced oil rate. Electronics controllers have been used to adjust many parameters of the oil wells and also to improve the efficiency of the gas lift injection system. This paper presents a intelligent control system applied to continuous gas injection in wells, based in production s rules, that has the target of keeping the wells producing during the maximum period of time, in its best operational condition, and doing automatically all necessary adjustments when occurs some disturbance in the system. The author also describes the application of the intelligent control system as a tool to control the flow pressure in the botton of the well (Pwf). In this case, the control system actuates in the surface control valve