Base change and theta correspondences for supercuspidal representations of SL(2)

Let F be a p-adic field with p odd. Quadratic base change and theta-lifting are shown to be compatible for supercuspidal representations of SL(2,F). The argument involves the theory of types and the lattice model of the Weil representation.Comment: This is a revison of a previous version of the paper. Typos have been corrected and more details of the argument have been adde

Investigation of Skylab data

There are no author-identified significant results in this report

Investigation of Skylab data

There are no author-identified significant results in this report

Investigation of Skylab data

There are no author-identified significant results in this report

Investigation of Skylab data

There are no author-identified significant results in this report

Monolithic ceramic analysis using the SCARE program

The Structural Ceramics Analysis and Reliability Evaluation (SCARE) computer program calculates the fast fracture reliability of monolithic ceramic components. The code is a post-processor to the MSC/NASTRAN general purpose finite element program. The SCARE program automatically accepts the MSC/NASTRAN output necessary to compute reliability. This includes element stresses, temperatures, volumes, and areas. The SCARE program computes two-parameter Weibull strength distributions from input fracture data for both volume and surface flaws. The distributions can then be used to calculate the reliability of geometrically complex components subjected to multiaxial stress states. Several fracture criteria and flaw types are available for selection by the user, including out-of-plane crack extension theories. The theoretical basis for the reliability calculations was proposed by Batdorf. These models combine linear elastic fracture mechanics (LEFM) with Weibull statistics to provide a mechanistic failure criterion. Other fracture theories included in SCARE are the normal stress averaging technique and the principle of independent action. The objective of this presentation is to summarize these theories, including their limitations and advantages, and to provide a general description of the SCARE program, along with example problems

Simplified cyclic structural analyses of SSME turbine blades

Anisotropic high-temperature alloys are used to meet the safety and durability requirements of turbine blades for high-pressure turbopumps in reusable space propulsion systems. The applicability to anisotropic components of a simplified inelastic structural analysis procedure developed at the NASA Lewis Research Center is assessed. The procedure uses as input the history of the total strain at the critical crack initiation location computed from elastic finite-element analyses. Cyclic heat transfer and structural analyses are performed for the first stage high-pressure fuel turbopump blade of the space shuttle main engine. The blade alloy is directionally solidified MAR-M 246 (nickel base). The analyses are based on a typical test stand engine cycle. Stress-strain histories for the airfoil critical location are computed using both the MARC nonlinear finite-element computer code and the simplified procedure. Additional cases are analyzed in which the material yield strength is arbitrarily reduced to increase the plastic strains and, therefore, the severity of the problem. Good agreement is shown between the predicted stress-strain solutions from the two methods. The simplified analysis uses about 0.02 percent (5 percent with the required elastic finite-element analyses) of the CPU time used by the nonlinear finite element analysis

Cyclic structural analyses of anisotropic turbine blades for reusable space propulsion systems

Turbine blades for reusable space propulsion systems are subject to severe thermomechanical loading cycles that result in large inelastic strains and very short lives. These components require the use of anisotropic high-temperature alloys to meet the safety and durability requirements of such systems. To assess the effects on blade life of material anisotropy, cyclic structural analyses are being performed for the first stage high-pressure fuel turbopump blade of the space shuttle main engine. The blade alloy is directionally solidified MAR-M 246 alloy. The analyses are based on a typical test stand engine cycle. Stress-strain histories at the airfoil critical location are computed using the MARC nonlinear finite-element computer code. The MARC solutions are compared to cyclic response predictions from a simplified structural analysis procedure developed at the NASA Lewis Research Center

Fracture mechanics concepts in reliability analysis of monolithic ceramics

Basic design concepts for high-performance, monolithic ceramic structural components are addressed. The design of brittle ceramics differs from that of ductile metals because of the inability of ceramic materials to redistribute high local stresses caused by inherent flaws. Random flaw size and orientation requires that a probabilistic analysis be performed in order to determine component reliability. The current trend in probabilistic analysis is to combine linear elastic fracture mechanics concepts with the two parameter Weibull distribution function to predict component reliability under multiaxial stress states. Nondestructive evaluation supports this analytical effort by supplying data during verification testing. It can also help to determine statistical parameters which describe the material strength variation, in particular the material threshold strength (the third Weibull parameter), which in the past was often taken as zero for simplicity

Concepts of Society in Official Statistics. Perspectives From Mobilities Research and Migration Studies on the Re-Figuration of Space and Cross-Cultural Comparison

Die Entstehung moderner Nationalstaaten ging historisch mit der Entwicklung spezifischer Verständnisse von Individuum, Bevölkerung und Gesellschaft, räumlichen Grenzen und Zugehörigkeiten einher. Über die amtliche Statistik, die ebenfalls in diesem Kontext entstanden ist, wurden diese politischen Konzepte zu messbaren Kategorien und empirischen Realitäten. Gegenstand dieses Beitrags ist die spezifische Konstitution von "Gesellschaft" durch die amtliche Statistik. Die Relevanz des statistischen Gesellschaftsverständnisses begründet sich dadurch, dass sie die Grundlage für Stichprobenziehungen in der standardisierten Sozialforschung und damit auch für die kulturvergleichende Sozialforschung bildet: Als Schlüssel zur Verallgemeinerung von Forschungsergebnissen von wenigen Fällen auf größere Maßstäbe erfordert die standardisierte Forschung Stichproben aus angebbaren Grundgesamtheiten. Typischerweise handelt es sich dabei um Register der amtlichen Statistik wie z.B. Einwohnermeldeämter. Dies wird in der Literatur jedoch als Container-Ansatz von Gesellschaft kritisiert, weil eine Kongruenz zwischen (nationalem) Territorium, Kultur und Gesellschaft angenommen wird, statt deren Verhältnis zu analysieren. Dies ist nicht nur eine methodische Schwachstelle, vielmehr affirmiert und naturalisiert diese Stichprobenstrategie den nationalen Rahmen von Gesellschaft und Kultur. Dadurch werden transnationale soziale Beziehungen und Identitätsrahmen verborgen. Hintergrund für die Analyse spezifischer Probleme und Versäumnisse in der amtlichen Statistik bildet die Kritik am skizzierten territorialen Gesellschaftsbegriff, die im Folgenden vorgestellt wird und sich insbesondere auf die Mobilitäts- und Migrationsforschung stützt.Historically, the emergence of modern nation-states has been accompanied by the development of a specific understanding of the individual, population and society, spatial boundaries and affiliations. With the help of official statistics, which developed complementary to the nation states, political concepts became measurable categories and empirical realities. The relevance of official statistics for constitution of "society" lies in the fact that it forms the basis for sampling strategies in standardized social research and thus also for comparative cultural social research: As the key to generalizing research results from a few cases to larger scales, standardized research requires samples from defined populations. However, this approach has been criticized in the literature as a container approach for society because it presupposes rather than analyses congruencies between (national) territory, culture and society. The issue at stake is not a mere methodological flaw, but the effect of the sampling strategy is to affirm and naturalize the national framework of society and culture. This hides transnational social relations and identity frameworks. The critique of the outlined territorial concept of society forms the background for the analysis of specific problems and omissions in official statistics