Stabilization of the Outenberg Hill in Geraardsbergen

A road, winding across the Oudenberg hill at Geraardsbergen, Belgium, and built partly in embankment and in excavation, suffered from three landslides from 1937 to 1966. Bored piles were used to nail the surface layers to the stable substratum, subsurface drainage to limit the fluctuations of the water table and a 220 m long low viaduct founded directly on bored piles to re-establish the traffic. Since the end of the works no additional movement appeared

Hereditary Connective Tissue Diseases in Young Adult Stroke: A Comprehensive Synthesis

Though the genetic background of ischaemic and haemorrhagic stroke is often polygenetic or multifactorial, it can in some cases result from a monogenic disease, particularly in young adults. Besides arteriopathies and metabolic disorders, several connective tissue diseases can present with stroke. While some of these diseases have been recognized for decades as causes of stroke, such as the vascular Ehlers-Danlos syndrome, others only recently came to attention as being involved in stroke pathogenesis, such as those related to Type IV collagen. This paper discusses each of these connective tissue disorders and their relation with stroke briefly, emphasizing the main clinical features which can lead to their diagnosis

Void fraction measurements of refrigerant flow in small diameter tubes using a capacitive sensor

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.The void fraction is one of the key parameters in two phase flows. Quite a few methods have been proposed to measure this void fraction. Yet many of these methods are quite complex, intrusive and/or are not applicable to all possible void fraction ranges. Capacitance measurements have already been shown to characterize the two phase flow behaviour of refrigerants. Due to the curvature of the electrodes for circular tubes, the measured capacitance does not vary linearly with the void fraction. In this work a method is proposed to calibrate a capacitive sensor and thus determine the void fraction based on capacitive measurements. The proposed method was applied to 270 measurement points. The tube diameter D for all these points is 8mm, the mass flux ranges from 200 to 500 kg/m²s and the vapour fraction ranges between 2.5% and 97.5%. Refrigerants R134a and R410A were used. The results for these data points were compared to the Rouhani-Axelsson drift flux void fraction model. A very good agreement with this model was observed.dc201

Partnerschappen tussen politie en wetenschap in België: fragiele allianties?

20 years of police reform seems to us to be an excellent moment to look back and find out what we can learn about partnerships between police and science in Belgium. Our contribution is based on (inter)national literature on the one hand and observations based on our experiences within the Centre for Policing and Security and the Innovation Network Iungos on the other. Our analysis shows that both partnerships have not been strengthened since the police reform in 1998 but, on the contrary, appear to be weakened. Indeed, both are subject to cultural tensions, a vulnerable institutional setting and fluctuating funding streams. Facing this reality in the Belgian context and naming the partnerships as fragile alliances provides a starting point to further reflect on how partnerships between police and science can be strengthened in our country in the future.Security and Global Affair

Using liquid air as a way to store energy

Paper presented at the 8th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Mauritius, 11-13 July, 2011.Energy storage is becoming an issue in a world were renewable energy will probably be the major way of energy production. Liquefaction of gasses in order to store the liquid is being looked at. This liquid can then be expanded in a Rankine cycle in order to recover the energy. If waste heat is used as input for the boiler, this can be an interesting technology to raise energy efficiency in industry. In this paper an analysis is made of the efficiency of storing liquefied air. Starting from the thermodynamics of the basic cycle, more complex combined cycles are studied. It is clear the ideal cycles have a good efficiency. Taking real expander efficiencies into account reduces the output a lot. Using combined cycles for liquefaction and energy production do not raise efficiency in a significant way. Conversion efficiencies are in the order of 20 to 50% , making these cycles comparable to hydrogen storage and compressed air storage.mp201

Samenwerking tussen politie en wetenschap: lessen uit België

Security and Global Affair

Design sensitivity analysis of using various in-tube condensation correlations for an air cooled condenser for ORCS

Papers presented to the 11th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 20-23 July 2015.The study is related to the evaluation of using 19 condensation heat transfer correlations in an annular finned horizontal round tube V-shaped air-cooled condenser design problem for a representative low-temperature waste heat recovery Organic Rankine Cycle (ORC) case. The condensation is realized through cold air provided by the fan suction at a mass flow rate of 90,35 kg/s, whereas the working fluid mass flow rate is 7,8 kg/s. The considered condensation temperature is 40°C which corresponds to a saturation pressure of 1,17 bar. The ambient air is considered to be 15°C. The investigated working fluid is SES36. For a given set of geometrical constraints, an iterative condenser design model is implemented. All considered correlations are applied separately for the same boundary conditions. The design sensitivity on the overall heat transfer coefficient, total transferred heat, required fan power, air- and refrigerant-side pressure drops is assessed. By those means, the engineering error margin of using different calculation tools in designing air-cooled condensers for ORC is reported.am201

Linear stabitlity analysis of a supercritical loop

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.Because of their unique properties, supercritical fluids are becoming increasingly popular for industrial applications. These fluids behave liquid like at low temperatures and gas like at higher temperatures, with a smooth transition in between. This makes them very suited as a solvent for chemical extraction and separation processes. Another important use is as a power fluid. Modern fossil fuel fired power plants all operate using supercritical water, and on a smaller power scale they are considered for organic rankine cycles and refrigeration. As they heat up, the density of a supercritical fluid changes shows a very sharp drop for temperatures close to the critical point. This large density difference can be used as the driving force to circulate the fluid in a loop, rather than using a pump. This idea is similar to natural circulation boiling loops, but the density difference is larger. It adds a layer of inherent safety to a design, as active components such as pumps are no longer required; but also adds an additional complexity: flow instabilities. It is well known from natural circulation boiling systems, that these loops can become unstable under certain conditions (e.g. high power and low flow rate). In this study, a simple supercritical loop is studied to determine the neutral stability boundary. This is done through linear stability analysis: the set of one-dimensional governing equations is first linearised and then the eigenvalues are determined. These describe the response, indicating if it is stable or not. The results indicate that there is a clear unstable area, which can be linked to different types of instabilities.dc201

Ice fraction estimation for ice slurries through impedance measurements

Papers presented to the 11th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 20-23 July 2015.A new approach to ice concentration measurement for ice slurries is proposed and investigated in this work. The technique is based on in-line measuring of the impedance of an ice slurry flow. An impedance sensor was designed and built to conduct experiments. The sensor measures the impedance of the ice slurry flow in a frequency domain ranging from 20 to 120 kHz. Using this broad range of measurements, multiple parameters are determined which are then linked to the ice concentration. Ethanol is utilized as freezing point depressant. The initial ethanol concentration was varied from 3 to 6 wt-% and ice fractions from 0 to 50 wt-% were used. The ice concentration was also determined using temperature, density and calorimetric measurement. These other techniques were used as a reference and compared to the proposed impedance measurement technique. The measurement accuracy was shown to be at odds with the accuracy of the other measuring techniques. Other advantages of the proposed measuring method are the possibility to perform the measurement in-line and the low cost of theam201