Classes of Multiple Decision Functions Strongly Controlling FWER and FDR

This paper provides two general classes of multiple decision functions where each member of the first class strongly controls the family-wise error rate (FWER), while each member of the second class strongly controls the false discovery rate (FDR). These classes offer the possibility that an optimal multiple decision function with respect to a pre-specified criterion, such as the missed discovery rate (MDR), could be found within these classes. Such multiple decision functions can be utilized in multiple testing, specifically, but not limited to, the analysis of high-dimensional microarray data sets.Comment: 19 page

High power arcjet

The activities on the development of the high power arc jet HIPARC, the thrust balance, and plasma diagnostic probes are discussed. Modifications of the HIPARC design and a synopsis of the materials used are given. Further experimental results with the TT30 thruster in the 50 kW range are presented. Some first calibration measurements of the thrust balance are also included. Progress concerning the development of plasma diagnostic devices is documented

Influence of stigmastanol and stigmastanyl-phosphorylcholine, two plasma cholesterol lowering substances, on synthetic phospholipid membranes : a 2H- and 31P-NMR study

Cholesterol, stigmastanol, and stigmastanyl-phosphorylcholine (ST-PC) were incorporated into model membranes composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) or 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC). POPC and ST-PC were deuterated at the lipid headgroup, DOPC at the cis-double bonds. The influence of the three sterols on the motion and conformation of the lipid headgroups and the hydrocarbon chains was monitored with 2H- and 31P-NMR. All three sterols were freely miscible with the lipid matrix in concentrations of up to 50 mol% without inducing phase separations or nonbilayer structures. However, the molecules exert quite different effects on the phospholipid bilayer. Cholesterol and stigmastanol are largely buried in the hydrocarbon part of the membrane, distinctly restricting the flexing motions of the fatty acyl chains whereas the conformation of the phospholipid headgroups is little affected. In contrast, ST-PC is anchored with its headgroup in the layer of phospholipid dipoles, preventing an extensive penetration of the sterol ring into the hydrocarbon layer. Hence ST-PC has almost no effect on the hydrocarbon chains but induces a characteristic conformational change of the phospholipid headgroups. The 2H- and 31P-NMR spectra of mixed phospholipid/ST-PC membranes further demonstrate that the PC headgroup of ST-PC has a similar orientation as the surrounding phosphatidylcholine headgroups. For both types of molecules the -P-N+ dipole is essentially parallel to the membrane surface. Addition of ST-PC induces a small rotation of the POPC headgroup towards the water phase

Vergleich eines magnetoplasmadynamischen und eines thermischen Plasmawindkanals zur Untersuchung von Hitzeschutzmaterialien von Raumfahrzeugen Endbericht

In the first part of the NASDA/IRS cooperation, the comparison of the magnetoplasmadynamic plasma wind tunnel of the IRS and the thermal plasma wind tunnel of NASDA/NAL was done by the investigation of basic oxidation protected ceramic C/C-TPS-materials provided by NASDA. A test condition which could be set in both facilities was used to test a C/C based material coated with two different SiC layers and a glass coating to gain information about the impact of the different types of plasma generation on this kind of material. The erosion rates in the thermal arcjet were lower than in the MPG facility although the heat flux necessary to reach the required surface temperature on the sample was significantly higher in the arcjet facility. An additional test series was performed in the MPG wind tunnel to study the influence of a composition of different protection layers made of candidate compounds for use in high-temperature TPS applications. It was found that at low temperatures and low pressures the silica based protection layer was unable to protect from substrate erosion by means of crack sealing. At higher temperatures this feature improved but erosion of the silica layer increased. The combination of a conversion SiC layer and a CVD-SiC layer revealed promising results in terms of their mechanical properties as well as their protective function against oxidation. Erosion of the C/C substrate was found to be particularly severe if a crack within the coating led down onto the graphite matrix between the fibers. It was also shown that self-passivation of a material may be strongly impeded by the high speed, high enthalpy environment typical for re-entry flight. Tests performed in a static facility revealed a different behavior of the material, the reason for which has to be analyzed in detail. (orig.)SIGLEAvailable from TIB Hannover: RR 1814(1997,4)+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany); Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA) GmbH, Bonn (Germany)DEGerman

PYREX. Ein Pyrometer zur Messung von Oberflaechentemperaturen an heissen Strukturen von Wiedereintrittskoerpern Endbericht

The present contribution describes, besides measurement results, also the setup and qualification for airworthiness. Starting from the PYREX experiment for the EXPRESS capsule, the pyrometer was further developed for a secondary payload mission in the German MIRKA capsule. The development step from the EXPRESS mission to the MIRKA unit consists in an extension to two measurement points, a multiplex electronics, and a further essential miniaturization of PYREX. (orig./AKF)SIGLEAvailable from TIB Hannover: RR 1814(1995,9)+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany); Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA) GmbH, Bonn (Germany)DEGerman

Numerische Stroemungsberechnung in einem thermischen Lichtbogentriebwerk mit Wasserstoff als Treibstoff Abschlussbericht

For a further increase of the performance of the high power arcjet 'HIPARC-R' developed and successfully tested at the Stuttgart University, the flowfield of the thruster has been computed. As a first step the flow calculation of the cold propellant gas without electric arc has been performed using the finite volume Navier-Stokes code NSFLEX. The flowfield is idealized as an axisymmetric laminar viscous reacting gas flow with an electric arc. The effects of current discharge and chemical reactions are taken in account by energy source terms resulting from ohmic heating and heat of reaction. For the calculation, the chemistry module, the current discharge code, and the flow field code were combined to determine the flow field, the chemical composition and the current density in the gas, and the calculation was repeated until convergence. The flow field is discretized with a structured curvilinear mesh with increased line concentration at the boundary walls. The discretized field includes a region beyond the nozzle exit to compare the numerical results with the experimental data. (WEN)Available from TIB Hannover: RR 1814(1996,7) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDeutsche Forschungsgemeinschaft (DFG), Bonn (Germany)DEGerman

Aufbau und Qualifikation eines Plasmawindkanals zur Untersuchung des Erosionsverhaltens von Hitzeschutzmaterialien Schlussbericht

This report describes the construction of the PWK2 plasma wind tunnel, which has been constructed over the past three years at the Institute for Space Systems of the University of Stuttgart under a grant from the Federal Minister for Research and Technology. This system provides a further instrument for simulating the conditions which apply when entering the atmosphere of a planet. The system has been constructed to supplement the PWK1 plasma wind tunnel, which until 1989 was the only system available in Europe for investigating heat-protection materials. While the PWK1 plasma wind tunnel is employed primarily for the purposes of materials development, PWK2 is to be used primarily for qualifying measuring processes for materials development, simulating the conditions which apply when entering the atmosphere of another planet and developing the plasma sources required for this purpose. Both plasma wind tunnels are suitable for qualifying oxidation-protected fiber composite ceramics made of C-C, C-SiC and SiC-SiC, and for investigating ablative materials in stagnation point flow. The simulation range of these plasma wind tunnels is presented and their operational limits are discussed by reference to several planned space missions. It is demonstrated that these plasma wind tunnels are particularly suitable for qualifying the intended heat-protection materials with regard to chemical resistance under heat. Particular attention is devoted to construction of the system, development of the new plasma source, the qualification of electrostatic and mechanical probes, the design of the Fabry-Perot interferometer and the development of processes to measure the surface temperatures of material specimens. (orig.)Der vorliegende Bericht beschreibt den Aufbau des Plasmawindkanals PWK2, der am Institut fuer Raumfahrtsysteme der Universitaet Stuttgart mit Foerderung des Bundesministers fuer Forschung und Technologie in den vergangenen drei Jahren aufgebaut wurde. Mit dieser Anlage steht nun ein weiteres Instrument zur Verfuegung, um die Eintrittsbedingungen in die Atmosphaere eines Planeten zu simulieren. Die Anlage wurde als Ergaenzung zum Plasmawindkanal PWK1 aufgebaut, der bis 1989 die einzig verfuegbare Anlage zur Untersuchung von Hitzeschutzmaterialien in Europa war. Waehrend der Plasmawindkanal PWK1 hautpsaechlich fuer die Materialentwicklung eingesetzt wird, liegt der Aufgabenschwerpunkt des PWK2 auf der Qualifikation hierfuer erforderlicher Messverfahren, der Simulation von Eintrittsbedingungen in die Atmosphaere anderer Planeten und der Entwicklung der hierfuer benoetigten Plasmaquellen. Beide Plasmawindkanaele eignen sich zur Qualifikation von oxidationsgeschuetzten Faserverbundkeramiken aus C-C, C-SiC und SiC-SiC und zur Untersuchung ablativer Materialien in Staupunktstroemung. Der Simulationsbereich dieser Plasmawindkanaele wird dargestellt und ihre Einsatzgrenzen werden am Beispiel einiger geplanter Raumflugmissionen diskutiert. Es wird gezeigt, dass sich diese Plasmawindkanaele fuer die Qualifikation der vorgesehenen Hitzeschutzmaterialien hinsichtlich chemischer Beanpsruchung unter Waermelast besonders eignen. Besondere Aufmerksamkeit wird neben dem Aufbau der Anlage, der Neuentwicklung der Plasmaquelle, der Qualifikation von elektrostatischen und mechanischen Sonden, der Auslegung des Fabry-Perot-Interferometers und der Entwicklung von Verfahren zur Messung der Oberflaechentemperatur von Materialproben gewidmet werden. (orig.)SIGLEAvailable from TIB Hannover: FR 6719 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman