SEI: An update

An update on the Space Exploration Initiative (SEI) is given in viewgraph form. Topics covered include the key prerequisites of human exploration, project planning, Mars and lunar explorations, supporting technologies, near-term strategies for SEI, human support elements, and Space Station Freedom SEI accommodations

Flight tests of IFR landing approach systems for helicopters

Joint NASA/FAA helicopter flight tests were conducted to investigate airborne radar approaches (ARA) and microwave landing system (MLS) approaches. Flight-test results were utilized to prove NASA with a data base to be used as a performance measure for advanced guidance and navigation concepts, and to provide FAA with data for establishment of TERPS criteria. The first flight-test investigation consisted of helicopter IFR approaches to offshore oil rigs in the Gulf of Mexico, using weather/mapping radar, operational pilots, and a Bell 212 helicopter. The second flight-test investigation consisted of IFR MLS approaches at Crows Landing (near Ames Research Center), with a Bell UH-1H helicopter, using NASA, FAA, and operational industry pilots. Tests are described and results discussed

Ultracold collisions in tight harmonic traps: Quantum defect model and application to metastable helium atoms

We analyze a system of two colliding ultracold atoms under strong harmonic confinement from the viewpoint of quantum defect theory and formulate a generalized self-consistent method for determining the allowed energies. We also present two highly efficient computational methods for determining the bound state energies and eigenfunctions of such systems. The perturbed harmonic oscillator problem is characterized by a long asymptotic region beyond the effective range of the interatomic potential. The first method, which is based on quantum defect theory and is an adaptation of a technique developed by one of the authors (GP) for highly excited states in a modified Coulomb potential, is very efficient for integrating through this outer region. The second method is a direct numerical solution of the radial Schr\"{o}dinger equation using a discrete variable representation of the kinetic energy operator and a scaled radial coordinate grid. The methods are applied to the case of trapped spin-polarized metastable helium atoms. The calculated eigenvalues agree very closely for the two methods, and with those computed self-consistently using the generalized self-consistent method.Comment: 11 pages,REVTEX, text substantially revised, title modifie

Connecting Hodge and Sakaguchi-Kuramoto through a mathematical framework for coupled oscillators on simplicial complexes

Phase synchronizations in models of coupled oscillators such as the Kuramoto model have been widely studied with pairwise couplings on arbitrary topologies, showing many unexpected dynamical behaviors. Here, based on a recent formulation the Kuramoto model on weighted simplicial complexes with phases supported on simplices of any order k, we introduce linear and non-linear frustration terms independent of the orientation of the k + 1 simplices, as a natural generalization of the Sakaguchi-Kuramoto model to simplicial complexes. With increasingly complex simplicial complexes, we study the the dynamics of the edge simplicial Sakaguchi-Kuramoto model with nonlinear frustration to highlight the complexity of emerging dynamical behaviors. We discover various dynamical phenomena, such as the partial loss of synchronization in subspaces aligned with the Hodge subspaces and the emergence of simplicial phase re-locking in regimes of high frustration

Intra-generational encounters with balloons and bread rolls: exploring reciprocity in post/age pedagogic spaces

File replaced (published version) on 26/5/23 by NK (LDS)This writing originates from unease with assumptions that often shape intergenerational practices and everyday encounters in the UK, for instance, assumptions about generational ‘gaps’ or ‘roles’ and the pedagogy of ‘interventions’ to promote meetings ‘between’ ages. Such interventions are usually predicated on chrono-logical notions of infant, child, youth, old age, and life stages. Haynes and Murris suggest dis-continuing age/stage-related categorisation by imagining post-age spaces and pedagogies and proposing intra-generational practice. Quinn and Blandon bring ageist ideas of the ‘human’ into question through their posthuman research on dementia and life-long learning. Thinking with such provocations, we re-visited accounts of our own intergenerational experiences, and inspired by Barad, diffractively re-turned them through a selection of readings. Responding to Mannion and Haynes and Murris we work with the concept of reciprocity understood as flowing through adult/child and human/more-than-human bodies. This shifted attention onto the intra-active happenings and ‘at-onceness’ of generational or multi-age in/en-counters. We troubled ageist discourses of deficit implicit in the notion of ‘gap-bridging’ and generated the concepts of ‘shouldness’, describing the kind of ‘forced play’ of such bridging interventions; and ‘nowing’ defying the chronos of age-based categorisation, to (re)imagine qualities of intra-generational encounters

Charge Exchange Processes between Excited Helium and Fully Stripped Ions

We made a classical trajectory Monte Carlo (CTMC) calculation of state selective cross sections for processes between some light ions and excited helium. The results, useful for analysis of spectroscopic data of fusion devices, are in good agreement with theoretical predictions of scaling laws.Comment: LaTex, 8 pages, 4 figures (available on request to the authors), DFPD/94/TH/57, to be published in Phys. Rev.