MacSphere

Monitoring and Advising System for Iodine Status

2017-07-14T19:46:39Z

Title: Monitoring and Advising System for Iodine Status Authors: Tayebi, Lobat Abstract:

Iodine-125 is produced from Xe-124 at McMaster Nuclear Reactor (MNR) for medical applications. Excessive amounts of this isotope in the air of the reactor site can be hazardous especially for the staff members who are continuously working at the reactor building. Therefore there is a critical need to monitor the concentration of iodine released to the air. In the previous iodine monitoring system available at MNR, there were several technical and practical problems. Consequently a new monitoring system was designed to overcome the previous problems and to provide with further facilities for the staff. The system is developed in the LabVIEW1 platform and is easily maintainable. The external data acquisition board LabJack is used to transfer the data to the PC. Briefly, by using radiation monitoring techniques and statistical methods, a computerized embedded system is designed to keep the MNR a safe place for operators and visitors. This thesis examines in detail the design and implementation of the new monitoring system, MASIS.

Downscaling Meteorological Predictions for Short-Term Hydrologic Forecasting

2017-07-14T19:18:57Z

Title: Downscaling Meteorological Predictions for Short-Term Hydrologic Forecasting Authors: Liu, Xiaoli Abstract:

This study investigates the use of large scale ensemble weather predictions provided by the National Centers for Environmental Prediction (NCEP) medium range forecast (MRF) modeling system, for short-term hydrologic forecasting. The weather predictors are used to downscale daily precipitation and temperature series at two meteorological stations in the Saguenay watershed in northeastern Canada. Three data-driven methods, namely, statistical downscaling model (SDSM), time lagged feedforward neural network (TLFN), and evolutionary polynomial regression (EPR), are used as downscaling models and their downscaling results are compared. The downscaled results of the best models are used as additional inputs in two hydrological models, Hydrologiska Byrans Vattenbalansavdelning (HBV) and Bayesian neural networks (BNN), for up to 14 day ahead reservoir inflow and river flow forecasting. The performance of the two hydrological forecasting models is compared, the ultimate objective being to improve 7 to 14 day ahead forecasts.

The downscaling results show that all the three models have good performance in downscaling temperature time series, the correlation between the observed and downscaled data is more than 0.90, however the downscaling results are less accurate for precipitation, the correlation coefficient is no more than 0.62. TLFN and EPR models have quite close performance in most cases, and they both perform better than SDSM.

Therefore the TLFN downscaled meteorological data are used as predictors in the HBV and BNN hydrological models for up to 14 day ahead reservoir inflow and river flow forecasting, and the forecasting results are compared with the case where no downscaled data is included. The results show that for both reservoir inflow and river flow, HBV models have better performance when including downscaled meteorological data, while there is no significant improvement for the BNN models. When comparing the performance of HBV and BNN models through scatter plots, it can be found that BNN models perform better in low flow forecasting than HBV models, while less good in peak flow forecasting.

Peak Discharge Estimation for Rural Areas Using APSWM and OTTHYMO Models

2017-07-14T18:28:27Z

Title: Peak Discharge Estimation for Rural Areas Using APSWM and OTTHYMO Models Authors: Dai, Jianping Abstract:

Traditional methods for flood estimation can be categorized as (1) simplified methods, e.g., regression analysis, (2) frequency analysis of streamflow data, (3) design storm-based precipitation-runoff modeling, and ( 4) continuous precipitation-runoff simulation modeling. The new approach - the Analytical Probabilistic Stormwater Model - was developed as an alternative to provide an efficient way of getting realistic estimation of peak discharges of desired frequencies for use in stormwater management of urban areas. To extend APSWM's application to rural areas, a series of comparisons were made between the calibrated design storm-based OTTHYMO model results, frequency analysis results and APSWM results for the Ganaraska River watershed. Special considerations were given to the transformation of the input parameter values of OTTHYMO model to those of APSWM. Comparable results were obtained for large floods, while APSWM may underestimate peak discharges of low return periods. Upon further testing and development, APSWM may be used for large rural areas.

Thermal and flow characteristics of an electrohydrodynamically enhanced capillary evaporator

2017-07-14T17:48:07Z

Title: Thermal and flow characteristics of an electrohydrodynamically enhanced capillary evaporator Authors: Komeili, Behrooz Abstract:

Experimental investigations have been conducted for an Electrohydrodynamically enhanced capillary evaporator (EHD-ECE) for enhancement of liquid evaporation, hence the flow rate. A capillary evaporator has a liquid channel inlet and a vapour channel exit. Inside the evaporator is a porous media that separates the liquid and vapour, which is also responsible for the capillary action. When an external electric field is applied inside the liquid side of the evaporator, the capillary action may be enhanced due to external body forces. Voltage was applied to the 3.lmm electrode, in the centre axis of the evaporator liquid channel. The environmentally friendly HFC-134a is used as the working fluid. The coaxial cylindrical evaporator centre is liquid filled and surrounded by a porous polyethylene wick, where the vapour channels are located on the other side of the wick. Heat is applied to the outer diameter of the evaporator. Experiments were conducted for applied heat loads from 0 to 80W and applied electric fields of de voltages from 0 to -5kV and 5kV, as well as frequencies ranging from 5-200Hz with applied pulse voltages of -IOkV and 5kV. Thermal temperatures of the liquid inlet, vapour exit, and evaporator wall, pressure difference across the evaporator, system pressure and liquid flow rates are measured and analysed.

The experimental results show that the vapour flow rate increases with increasing applied voltages and enhancement up to a maximum of 202% was achieved when 5kV de was applied with a heat input of 80W. The polarity of the applied voltage had only a slight effect as slightly higher flow rate enhancements were observed. The vapour flow rate was also enhanced for applied pulse voltage, where the vapour flow rate increased with increasing frequencies between 50Hz to 200Hz.

With the application of de and pulsed electric fields, the vapour flow rate due to the external body forces acting on the liquid-vapour interface are enhanced. Future work is required to fully understand the phenomena and more optimization studies are required for the EHD-CPL.