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Quantification of natural ventilation rates is an important issue in HVAC system design. Natural ventilation in buildings depends on many parameters whose uncertainty varies significantly, and hence the results from a standard deterministic simulation approach could be unreliable and provide a false sense of security that natural ventilation will supply adequate amounts of fresh air. This study performed an uncertainty analysis to predict natural airflow rates. The paper presents relevant uncertainty in model and input parameters such as meteorological data, building properties (leakage areas of windows, doors, etc.), etc. Uncertainties of the aforementioned parameters were quantified based on data available from literature and on-site visits. The Monte-Carlo method with Latin Hypercube Sampling (LHS) was used for uncertainty propagation. The CONTAMW was chosen to simulate natural ventilation phenomena in a high-rise apartment building that is typical of residential buildings in Korea. It is shown that the uncertainty propagated through this process is not negligible and may significantly influence the prediction of the airflow rates. In the paper, the result of a sensitivity analysis is also addressed. Practical application: The paper describes a probablistic approach to predict the natural airflow rates of high-rise apartment buildings under uncertainty and could eventually replace the current conventional deterministic approach.

A simple method for determining the doped fibre length and the pump power of gain-flattened EDFAs has been proposed on the basis of average inversion of the erbium ions with maximum gain flatness. The difference between the obtained and the desired gains to achieve the output power per channel of -5-+5 dBm while maintaining the maximum gain flatness was

An ion beam assisted deposition (IBAD) technique has been explored for the growth of refractory W and WNx films on n‐GaAs as candidate gate materials for GaAs integrated circuits. Tungsten was deposited by Ar‐ion beam sputtering, and simultaneously low energy nitrogen ions were introduced directly onto the GaAs substrate, using a Kaufman‐type ion gun, for nitridation of the W deposits. The deposited films were characterized by electrical resistivity measurements, x‐ray diffraction, and x‐ray photoelectron spectroscopy analyses. The results showed that the composition and the electrical resistivity could be controlled with the nitrogen‐ion dose. Thermal stability of the WNx /GaAs interfaces was also investigated by examining Schottky diode characteristics and microstructures. The WNx contacts investigated in the composition range from x=0 to 0.47 were electrically stable up to 850 °C and showed remarkable enhancements in the Schottky barrier height through high temperature annealing. Such annealing induced...