Applications of a High-Altitude Powered Platform (HAPP)

A list of potential uses for the (HAPP) and conceptual system designs for a small subset of the most promising applications were investigated. The method was to postulate a scenario for each application specifying a user, a set of system requirements and the most likely competitor among conventional aircraft and satellite systems. As part of the study of remote sensing applications, a parametric cost comparison was done between aircraft and HAPPS. For most remote sensing applications, aircraft can supply the same data as HAPPs at substantially lower cost. The critical parameters in determining the relative costs of the two systems are the sensor field of view and the required frequency of the observations being made. The HAPP is only competitive with an airplane when sensors having a very wide field of view are appropriate and when the phenomenon being observed must be viewed at least once per day. This eliminates the majority of remote sensing applications from any further consideration

Drag reduction of cylinders by partial porous coating

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.The paper summarizes experimental investigations concerning drag reduction of circular cylinders by porous coating. In order to quantify the effect, wind tunnel experiments with a force balance and flow field analyses have been carried out. In a first experiment, the cylinders were coated completely with a thin porous layer. The results show that the boundary layer over the porous surface is turbulent right from the beginning and thickens faster because of the enhanced vertical momentum exchange when compared to a smooth cylinder surface. The region of flow detachment is widened resulting in a broader area with almost vanishing low flow velocities. All in all, the measurements show that a full porous coating of the cylinders increase the flow resistance. In a second experiment, the cylinders were coated only on the leeward side, which resulted in a reduction of the body's flow resistance. This effect seems due to the fact that the recirculating velocity and the underpressure in the wake is reduced significantly through a leeward porous coating. Thus, combining a smooth non-permeable windward side with a porously coated leeward side can lead to a drag reduction of the body. These findings can be applied advantageously in many technical areas, such as energy saving of moving bodies (cars/trains/planes) or in reducing fluid loads on submersed bodies.dc201

Winter storm risk of residential structures ? model development and application to the German state of Baden-Württemberg

International audienceThe derivation of probabilities of high wind speeds and the establishment of risk curves for storm damage is of prime importance in natural hazard risk analysis. Risk curves allow the assessment of damage being exceeded at a given level of probability. In this paper, a method for the assessment of winter storm damage risk is described in detail and applied to the German state of Baden-Württemberg. Based on meteorological observations of the years 1971?2000 and on damage information of 4 severe storm events, storm hazard and damage risk of residential buildings is calculated on the level of communities. For this purpose, highly resolved simulations of storm wind fields with the Karlsruher Atmospheric Mesoscale Model (KAMM) are performed and a storm damage model is developed. Risk curves including the quantification of the uncertainties are calculated for every community. Local differences of hazard and risk are presented in state-wide maps. An average annual winter storm damage to residential buildings of minimum 15 million Euro (reference year 2000) for Baden-Württemberg is expected

Induced Bradycardia Effects on Angiogenesis, Growth and Development in Early Development in Chicken Embryos, Gallus domesticus

Ruck, Sylvia A. Induced Bradycardia Effects on Angiogenesis, Growth and Development in Early Development in Chicken Embryos, Gallus domesticus. Master of Science (Biology), December 2010, 42 pp., 9 illustrations, references, 44 titles. Cardiac performance, angiogenesis and growth was investigated during early chicken development. Heart rate, and thus arterial pulse pressure and cardiac output, were altered with the bradycardic drug ZD7288. Heart rates at 72 h of development of control embryos and those dosed with chicken Ringer were not different at 171 bpm. Acute and chronic application of ZD7288 caused significant bradycardia. Chronic dosing of Ringer and ZD7288 changed neither eye diameter nor development rate. Chronic dosing of ZD7288 did not significantly alter CAM vessel density close to the embryo (2, 3 and 4 mm) but at farther distances (5 and 6 mm) chronic dosing with both Ringer and ZD7288 decreased vessel density by 13 -16%. Chronic dosing with ZD7288 also reduced body mass by 20%. Thus, lowered heart rate and cardiac output had little effect on vessel density or developmental stage, but did reduce embryo growth. i