By measuring the halothane concentrations in samples of air from three different operating theatres during routine operating lists the pattern of spread of the waste anaesthetic gases has been demonstrated. The results show that in all the theatres there was a spread of halothane from its point of escape from the anaesthetic circuit to all parts of the theatre air. A turbulent flow ventilation ...

This paper presents CFD simulations of natural displacement ventilation airflows in which the buoyancy force produced by a heat source is opposed by a wind force. Cases investigated focus on windbuoyancy force relationships for which a two-layer stratification is maintained. CFD predictions of the position of the interface separating the two layers and the change in reduced gravity (temperature...

Accurate and reliable CFD simulation of temperature stratification in indoor environment is needed for the design and evaluation of displacement ventilation in buildings. This paper presents a detailed and systematic evaluation of the capability of 3D steady RANS CFD simulations to predict the temperature stratification in a room. The evaluation is based on sensitivity analysis and validation w...

This paper illustrates a step-by-step process on how to use "The Manual for Verification, Validation, and Reporting of Indoor Environment CFD analyses" developed by ASHRAE. The details of the manual are further explained through an example of indoor environment modeling (an office with mechanical displacement ventilation). The verification, validation, and reporting do not have to be documented...

Congenital lobar emphysema is an uncommon bronchopulmonary malformation characterized by lobar overinflation and accompanying alveolar septum damage that leads to compression atelectasis of the lung parenchyma and displacement of mediastinal structures, with the resultant ventilation-perfusion mismatch. We present a case of a 33-year-old lady with progressive exertional dyspnea. Chest radiograp...

Background: Weaning from mechanical ventilation in the intensive care unit is an important step in the treatment process. More patients in less than 6 hours after cardiac surgery can be separated from mechanical ventilation and extubated. However, 20-40% of patients after cardiac surgery, due to dysfunctional ventilator weaning response (DVWR), still remain under mechanical ventilation. Therefo...

This research concerns the mathematical and physical modelling of the buoyancy-driven flow of warm air at night from a multi-storey atrium building by displacement ventilation. The process of clearing warm air from a building at night is known as ‘night-purging’. The primary aim of this research was to enhance understanding of these flows to thereby facilitate efficient design of passively nigh...

The convective heat transfer coefficient (CHTC) is a crucial parameter for night ventilation performance estimation. This paper investigates the of with diffuse ceiling (DCV) concept in an office room. A series dynamic full-scale experiments were conducted different thermal mass distribution schemes, air change rates per hour (ACH), and supply temperatures. CHTC at interior surfaces inlet outle...

One main challenge of air distribution in classrooms is to guarantee ventilation performance under different usage conditions. In this study, the indoor climate summer and winter conditions with occupancy densities classroom presented. Thermal condition measurements a half-size were performed test room four suppliers: wall-grilles, ceiling diffusers, perforated duct displacement ventilation. Th...