ESA’s Drop Tower Utilisation Activities 2000 to 2011

The European Space Research and Technology Center ESTEC, ESA’s premises in Noordwijk, The Netherlands, has a long lasting cooperation with the ZARM-FAB (Centre of Applied Space Technology and Microgravity—Drop Tower Operation and Service Company) in Bremen on the utilization of the Drop Tower for ground-based microgravity research and space hardware development studies. During the period January 2000 to December 2011 ESA will have procured in total some 840 drops addressing a variety of scientific and technological disciplines. The experiments are usually carried out in campaigns of 15 to 20 drops each, with an annual average of about 5 campaigns. The cooperation agreement between ESA and the ZARM-FAB includes experiment preparation advice by ZARM’s experts, the integration of the hardware into the drop capsule, dedicated safety reviews, the execution of the drop or catapult experiments, the post-flight payload de-integration as well as the handover of acquired data to the experimenters. The experiment hardware itself is provided by the scientists or has to be procured from sources outside of ESA’s drop tower utilization contract. ESA appreciates the cooperation of the ZARM-FAB in Bremen whose drop- and catapult facility provides excellent microgravity quality, is operated by a highly competent, flexible and extremely supportive expert team, allows campaign integration at relatively short notice throughout the entire year, offers real-time experiment operations and immediately after each drop delivers experiment results and provides on-site hardware modification possibilities.     

FPGA价格不是衡量系统成本的最好指标

大多数工程师都知道现有三种基本的FPGA技术:反熔丝、FLASH和SRAM.其中,SRAM是迄今为止应用范围最广的架构,主要因为它具有可重编程能力,而反熔丝FPGA只提供一次可编程(OTP)方案.……     

EEG alpha spindles and prolonged brake reaction times during auditory distraction in an on-road driving study

Driver distraction is responsible for a substantial number of traffic accidents. This paper describes the impact of an auditory secondary task on drivers’ mental states during a primary driving task. N = 20 participants performed the test procedure in a car following task with repeated forced braking on a non-public test track. Performance measures (provoked reaction time to brake lights) and brain activity (EEG alpha spindles) were analyzed to describe distracted drivers. Further, a classification approach was used to investigate whether alpha spindles can predict drivers’ mental states.     

Avoiding the potential pitfalls of using negative priming tasks in developmental studies: Assessing inhibitory control in children, adolescents, and adults.

Despite being ignored, visual distractors often produce traceable negative priming (NP) effects that can be used to investigate inhibitory processes. Robust NP effects are typically found with young adults, but not with children. Using 2 different NP tasks, the authors compared NP in 5 different age groups spanning 5 to 25 years of age. The 1st task revealed comparable NP between all age groups, but a linear decrease in NP through childhood to early adulthood. In the 2nd task, NP decreased linearly into adulthood, with children actually showing larger NP than adults. This Age Group ? NP interaction was eliminated, however, when reaction time data were log transformed to control for age differences in overall processing speed. When appropriately transformed data were used, both experiments showed that NP was intact and comparable between children, adolescents, and adults, and suggested that an inhibitory process is fully developed by early childhood. The results highlight how potential pitfalls might be avoided when comparing NP in children and adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Spatial Extension to the π Calculus

Spatial dynamics receive increasing attention in Systems Biology and require suitable modeling and simulation approaches. So far, modeling formalisms have focused on population-based approaches or place and move individuals relative to each other in space. SpacePi extends the π calculus by time and space. π processes are embedded into a vector space and move individually. Only processes that are sufficiently close can communicate. The operational semantics of SpacePi defines the interplay between movement, communication, and time-triggered events. A model describing the phototaxis of the Euglena micro-organism is presented as a practical example. The formalism's use and generality is discussed with respect to the modeling of molecular biological processes like diffusion, active transportation in cell signaling, and spatial structures.     

Rohrleitungsplanung und Materialwirtschaft mit unterschiedlichen Datenstrukturen der Rohrleitungsklassen von Anlagenbetreibern

Pipework Planning and Material Management with Differing Data Structures of the Pipe Classes Employed by Plant Users. Engineering quality depends not least on good coordination and smooth flow of information between the individual disciplines. A major aim of CAD – apart from rationalization – is to improve the quality of engineering work. This is why all the plant users and engineering firms have introduced computer systems to support their piping work. Pipe classes had to be stored in accordance with the data structures prescribed by the respective computer systems. This has led to differences in the definitions of piping items. Different identifiers and data structures are an obstacle to cooperation. Economic aspects and comprehensive documentation requirements imposed by new regulations call for suitable structures to ensure smooth data flow between the various systems.     

Influence of reactant characteristics on the microstructures of combustion-synthesized titanium carbide

The influence of reactant characteristics on morphological development through the stages of combustion synthesis was investigated using a titanium-carbon system. The effect of the characteristics of a variety of carbons (carbon blacks, graphites, and cokes) and a variety of titanium powders on the density and microstructure of combusted and uncombusted sample compacts was studied. The size of the titanium particles had a relatively small influence on the density of the final (TiC) product but had a significant effect on its microstructure. The structure of the carbon blacks (as judged by the n-dibutyl phthalate absorption number, DBP) had a direct influence on the density of the uncombusted and combusted samples: low-structure carbon blacks resulted in higher densities for both cases. Products made with natural graphites had higher densities than those made with synthetic graphites. The surface area of carbon and graphite reactant powders had less influence on the density of the product than on its network morphology. Cored structures in TiC products made from certain carbon and graphite powders were observed and are explained in terms of their ash (oxide) content.     

Zeitlicher Druckverlauf bei Explosionen als Grundlage zur Auslegung von Behältern und Apparaten

Time-dependent behaviour of pressure in cases of explosions: A basis for design of pressure vessels and apparatus . The knowledge of the maximum explosion pressure is important for design of pressure vessels subject to danger of explosion. Especially for non-spherical geometries or plant-internal pressure relief, the maximum explosion pressure has to be calculated from the time-dependent pressure caused by a chemical reaction in the vessel. Therefore, a set of ordinary differential equations was solved numerically by means of the method of differences. Examples are drawn from known experimental studies. Turbulence effects are also considered. As a result, an analytical relationship is derived which gives the necessary pressure relief area. Finally the results are compared with those of available formulas. Deviations are explained in detail.