Experiments for electromagnetic levitation in microgravity

Containerless processing is a promising research tool for investigating the properties of undercooled melts and their solidification. For conducting samples RF-electromagnetic levitation offers the possibility to obtain large undercoolings by avoiding heterogeneous nucleation at container walls. On earth, however, strong magnetic fields are needed to compensate the gravitational force which imposes a lower limit on the available temperatures and on the accessible undercooling range. Under microgravity conditions the magnetic positioning fields can be minimized and hence, undercooling becomes feasible under ultra-high vacuum conditions and lower temperatures become accessible. In contrast to other undercooling and solidification techniques, electromagnetic levitation allows for diagnostic measurements during the early steps of nucleation and phase selection. Experiments cover a wide field of research topics: nucleation, directional solidification at high velocities, generation of metastable phases, evolution of microstructures, properties of undercooled liquids. Examples from these classes including experiments selected for the IML-2 mission are discussed with emphasis on technical requirements. An overview is given on the German TEMPUS (electromagnetic levitation facility) program

Modulation der Granulozytenfunktionalität durch Priming

Zusammenfassend lässt sich sagen, dass keine relevanten Unterschiede in Hinblick auf eine Modulation der Granulozytenfunktionalität in Form eines Primingeffektes mit den untersuchten Substanzen TNF-α, IL-1ß und IL-6 erkennbar sind. Somit können wir die Existenz eines Primings mit der von uns verwendeten Methodik nicht bestätigen. Mit dem Schwerpunkt auf den zeitlichen Abläufen der ROS-Produktion sowie NETosis, also einem möglichen früheren oder späteren Einsetzen, lässt sich kein Priming erkennen. Das Ausmaß der Migration zeigt keine Verstärkung oder Abnahme durch die Vorbehandlung, sodass wir auch hier keinen Effekt sehen. Mit dem verwendeten System kann der verwendete Lockstoff fMLP als geeigneter chemotaktisch wirksamer Stimulus verifiziert werden. Die Zellmigration sowie die stattfindende ROS-Produktion und NETosis lassen sich mit dieser Methodik der mikroskopischen Untersuchung mithilfe der ibidi-Kammer und der Auswertung mittels der Imaris-Software gut beobachten und es kann ein genauer Einblick in das Verhalten der Granulozyten gewonnen werden. Außerdem führen unsere Untersuchungen zu der Feststellung starker inter- sowie intraindividueller Unterschiede in den Ergebnissen der getesteten Probanden, was eine parallele Interpretation mit der zugehörigen Kontrollgruppe erforderlich macht. Eine Beeinflussbarkeit der Ergebnisse durch die verwendete Aufreinigungsmethode können wir bestätigen und finden eine im Vergleich mit der Doppelgradientzentrifugation geringere Voraktivierung der Granulozyten bei der positiven Selektion

TEMPUS: First results

The electromagnetic levitation facility, TEMPUS, developed by Dornier is designed to operate under microgravity conditions. Compared to terrestrial levitation, microgravity offers the possibility to melt and undercool in ultra high vacuum, thereby, providing an ultra clean environment. The technical concept of the TEMPUS facility was tested on two KC 135 flights and in the Texus 22 mission. Preparative investigations concerning the coil system and the heating and positioning efficiencies were carried out in the TEMPUS laboratory version. Furthermore, temperature-time profiles were determined under various boundary conditions. As a consequence of processing liquid metals under UHV, correct temperature measurement arises as the most critical problem. Experiences with experiments in the TEMPUS laboratory module show that due to the evaporation losses of the sample, the transmission of the CaF2 shielding windows changes drastically during the processing time. The investigation of the effect of contamination on pyrometry and the development of alternative evaporation shielding methods were initiated. During the second KC 135 flight, it was possible to heat up and melt an FeNi sample under He atmosphere. Oscillations of the molten sample, which were excited by switching out the magnetic heating field, could be detected and afterwards analyzed. From the frequency of these oscillations the surface tension of the sample material could be derived. The measurement of the surface tension and viscosity of an undercooled metal is proposed for TEMPUS on IML-2. This document is presented in view graph form

Estudio de la hidrogenación del aceite de jojoba

Trials were cattied out on jojoba oil hydrogenation to study the effects of the main operative variable on iodine index and melting point. . A batch reactor with nickel catalysts was used. The effects selected for analysis were the reaction temperature, the operation pressure and the amount of catalyst.The range of temperature studied was 120-200ºC, the pressure was between 2 and 4 atm and the amount of catalyst ranged from 0.2 – 0.6% (percentage of catalyst mass over oil mass). The results showed that these three factors affected the reaction significantly; although temperature was the most influential in the progression of the reaction. In addition, the kinetic behavior was studied using a potential model of pseudo-first order and the corresponding kinetic parameters were obtained.Se han llevado a cabo ensayos de hidrogenación de aceite de jojoba para estudiar los efectos de las principales variables operativas de esta operación sobre el índice de yodo y el punto de fusión. Se utilizó un reactor discontinuo con un catalizador de níquel. Los efectos seleccionados para su análisis fueron la temperatura de reacción, la presión de operación y la cantidad de catalizador. El rango de temperaturas estudiado fue de 120-200ºC, el de presión entre 2 y 4 atm y la cantidad de catalizador entre 0,2-0,6 % (% masa catalizador / masa de aceite). Si bien los tres efectos estudiados fueron significativos, la temperatura fue el efecto que más influencia tuvo sobre el avance de la reacción. Se estudió además el comportamiento cinético mediante el ajuste de un modelo potencial de pseudo-primer orden, obteniéndose los parámetros cinéticos correspondientes

Full-Stack Performance Model Evaluation using Probabilistic Garbage Collection Simulation

ABSTRACT Performance models can represent the performance relevant aspects of an enterprise application. Corresponding simulation engines use such models for simulating performance metrics (e.g., response times, resource utilization, throughput) and allow for performance evaluations without load testing the actual system. Creating such models manually often outweighs their benefits. Therefore, recent research created performance model generators, which can generate such models out of Application Performance Management software. However, a full-stack evaluation containing all relevant resources of an enterprise application (Central Processing Unit, memory, network and Hard Disk Drive) has not been conducted to the best of our knowledge. This work closes this gap using a pre-release version of the next generation industry benchmark SPECjEnterpriseNEXT of the Standard Performance Evaluation Corporation as example enterprise application, the Palladio Component Model as performance model and the performance model generator of the RETIT Capacity Manager. Furthermore, this work extends the generated model with a probabilistic garbage collection model to simulate memory allocation and releases more accurately

apex: A new commercial off-the-shelf on-board computer platform for sounding rockets

In order to supersede the aging Microchip ATMEGA328P as the de facto standard for Commercial off-the-shelf (COTS) On-Board Computers (OBCs) with a more powerful system for different kinds of high-speed sensors and image acquisition applications, we developed advanced processors, encryption, and security experiment (apex). The platform consisting of a newly developed OBC using COTS components has been flight tested during the ATEK/MAPHEUS-8 sounding rocket campaign. The main advantages of the apex OBC lies in the speed and simplicity of the design while maintaining operational security with a redundant master-master microcontroller system, as well as dual flash storage within each master. Additionally, a single board computer with a containerized and failure-resistant Operating System (OS) (balenaOS) was included to allow usage of a high-definition camera or other more compute-intensive tasks. The bench and flight tests were performed successfully and already showed feasible ways to further improve operational performance

"A Decentralized Operations Concept for the European Payloads on the International Space Station"

The European Module Columbus of the International Space Station (ISS) is planned to be launched 2004. For its exploitation phase as well as for the early utilisation of the Space Station starting from 2003 onwards the operations procedures are now being defined in detail and the implementation of specific infrastructure has started. A decentralised operations concept will allow the investigators to perform their experiments using the telescience technique of remote experiment operations whenever feasible. User Support and Operation Centres (USOCs) will act as Facility Responsible Centres (FRC) performing the operations for multi user experiment facilities. The Columbus Control Centre (COL-CC) will perform the Columbus system operations, co-ordinate the European payload operations and provide the European Communications network. This paper gives an overview on the operations concepts and the tasks and set up of the involved sites

К определению поверхностного натяжения, объема и площади криволинейной поверхности по форме сидячих пузырьков или висячих капель

The multi-user facility EXPOSE-E was designed by the European Space Agency to enable astrobiology research in space (low-Earth orbit). On 7 February 2008, EXPOSE-E was carried to the International Space Station (ISS) on the European Technology Exposure Facility (EuTEF) platform in the cargo bay of Space Shuttle STS-122 Atlantis. The facility was installed at the starboard cone of the Columbus module by extravehicular activity, where it remained in space for 1.5 years. EXPOSE-E was returned to Earth with STS-128 Discovery on 12 September 2009 for subsequent sample analysis. EXPOSE-E provided accommodation in three exposure trays for a variety of astrobiological test samples that were exposed to selected space conditions: either to space vacuum, solar electromagnetic radiation at > 110nm and cosmic radiation (trays 1 and 3) or to simulated martian surface conditions (tray 2). Data on UV radiation, cosmic radiation, and temperature were measured every 10 s and downlinked by telemetry. A parallel mission ground reference (MGR) experiment was performed on ground with a parallel set of hardware and samples under simulated space conditions. EXPOSE-E performed a successful 1.5-year mission in space