Design principles for pressure moderated window frames

High performance window frames that are widely used in Europe rely on pressure moderation to achieve a good weathertightness. By separating the airtightness plane from the water shedding surface a drained cavity can be pressure moderated. As wind pressure is the main driving force for water to infiltrate into the frame, a pressure equalized system is able to achieve higher performance levels. In this paper the performance of window frames is analyzed in two separate ways: first of all experimental research was conducted on a single frame to analyze the way it functions and fails, secondly a database of the university window testing facility was used to perform a parametric analysis. High frequency measurements on window frames provide for the information to model the pressure in the cavity and render information on prevalent parameters. The influence of different elements (section, joggles, gaskets, fittings) is examined in both dry as well as rainy conditions during static and dynamic pressure differences. The airtightness of the outer plane divided by the airtightness of the inner plane is the main parameter that will determine the watertightness potential of window frames. Based on the research carried out within the framework of that program and the analysis of the test reports in the database design principles have been determined requisite to achieve adequate pressure moderation in window frames

Mitigation of cross-saturation effects in resonance-based sensorless switched reluctance drives

The stator and rotor yoke in a switched reluctance motor form magnetic circuit parts that are typically shared by different phases. If these parts saturate due to the excitation of one phase, this will lead to a change of the magnetic characteristics of all other phases sharing these parts. In several position-sensorless methods, cross-saturation leads to a load-dependent position estimation error. In this paper, the influence of cross-saturation on a resonance-based position estimation method is studied. The method extracts position information from electrical resonances triggered in an idle motor phase. A cross-saturation mitigation scheme is presented in order to reduce the commutation position error. The scheme uses only one additional parameter per phase which can be measured automatically during commissioning of the drive. Experimental results at low and medium speed show that the position estimation error remains smaller dan 2 mechanical degrees over the rated load range

Watertightness of window frames: experience of notified bodies

The research facility for testing building envelope elements at Ghent University has been testing the air- and watertightness of windows for over 30 years. As a certified lab a lot of tests are done for the industry according to standard procedures. This paper presents the results and analysis of about 200 tests that were carried out throughout the last 10 years. Is the overall performance of the window correlated with the construction material? And does a good airtightness guarantee a corresponding watertightness? All too often the test samples delivered by the industry are an exception to the rule: while a grade A window is delivered to the lab, poor quality is general practice. Clients, architects and contractors need clear-cut specifications concerning performance assessment in order to obtain a high-quality product, and if there are apparent indications of defects or flaws the specifications should provide the possibility to put a randomly chosen window to the test. Based on the experience of the test lab as notified body guidelines for quality management in low-rise and high-rise buildings are developed

Development of a land use regression model for black carbon using mobile monitoring data and its application to pollution-avoiding routing

Black carbon is often used as an indicator for combustion-related air pollution. In urban environments, on-road black carbon concentrations have a large spatial variability, suggesting that the personal exposure of a cyclist to black carbon can heavily depend on the route that is chosen to reach a destination. In this paper, we describe the development of a cyclist routing procedure that minimizes personal exposure to black carbon. Firstly, a land use regression model for predicting black carbon concentrations in an urban environment is developed using mobile monitoring data, collected by cyclists. The optimal model is selected and validated using a spatially stratified cross-validation scheme. The resulting model is integrated in a dedicated routing procedure that minimizes personal exposure to black carbon during cycling. The best model obtains a coefficient of multiple correlation of R = 0.520. Simulations with the black carbon exposure minimizing routing procedure indicate that the inhaled amount of black carbon is reduced by 1.58% on average as compared to the shortest-path route, with extreme cases where a reduction of up to 13.35% is obtained. Moreover, we observed that the average exposure to black carbon and the exposure to local peak concentrations on a route are competing objectives, and propose a parametrized cost function for the routing problem that allows for a gradual transition from routes that minimize average exposure to routes that minimize peak exposure

Development and evaluation of land use regression models for black carbon based on bicycle and pedestrian measurements in the urban environment

Land use regression (LUR) modelling is increasingly used in epidemiological studies to predict air pollution exposure. The use of stationary measurements at a limited number of locations to build a LUR model, however, can lead to an overestimation of its predictive abilities. We use opportunistic mobile monitoring to gather data at a high spatial resolution to build LUR models to predict annual average concentrations of black carbon (BC). The models explain a significant part of the variance in BC concentrations. However, the overall predictive performance remains low, due to input uncertainty and lack of predictive variables that can properly capture the complex characteristics of local concentrations. We stress the importance of using an appropriate cross-validation scheme to estimate the predictive performance of the model. By using independent data for the validation and excluding those data also during variable selection in the model building procedure, overly optimistic performance estimates are avoided. (C) 2017 Elsevier Ltd. All rights reserved

Fully equipped half bridge building block for fast prototyping of switching power converters

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Rotor position estimation of switched reluctance motors based on damped voltage resonance

This paper proposes a method to obtain the rotor position of switched reluctance motors by means of voltage measurements. It is shown that the combination of motor and power-electronic converter defines a resonant circuit, comprised by the motor phase inductances and the parasitic capacitance of converter switches, power cables and motor phase windings. For salient machines in general, the associated resonance frequency of the circuit depends on the rotor position. In the position estimation method, an initial voltage distribution is imposed over the impedances of the resonance circuit, after which the circuit is let to oscillate freely. During this phase of free oscillation, the induced voltage over a phase winding exhibits a damped oscillatory behaviour, from which position information can be retrieved. An overview is given of different possibilities to trigger the voltage resonance. It is shown that the proposed position estimation method has favourable characteristics such as measurement of large-amplitude voltages, robustness against temperature deviations of motor and power semiconductors, very high update rates for the estimated position and absence of sound and disturbance torque. Experimental results are given for a sensorless commutation scheme of a switched reluctance motor under small load