Reusable Surface Insulation (RSI) Material Samples

Test specimen data sheets are presented for 48 high temperature and 40 low temperature reusable surface insulation tiles. Tabular data show dimensions, density, coating weight, and final tile weight. Codes indicate basic material, surface coating, and hydrophobic treatment

Lessons learned from the development and manufacture of ceramic reusable surface insulation materials for the space shuttle orbiters

Three ceramic, reusable surface insulation materials and two borosilicate glass coatings were used in the fabrication of tiles for the Space Shuttle orbiters. Approximately 77,000 tiles were made from these materials for the first three orbiters, Columbia, Challenger, and Discovery. Lessons learned in the development, scale up to production and manufacturing phases of these materials will benefit future production of ceramic reusable surface insulation materials. Processing of raw materials into tile blanks and coating slurries; programming and machining of tiles using numerical controlled milling machines; preparing and spraying tiles with the two coatings; and controlling material shrinkage during the high temperature (2100-2275 F) coating glazing cycles are among the topics discussed

Analysis and Identification of Requirements for a System to Enhance Situational Awareness at Sea

This paper presents the research results of identifying and analyzing key requirements for the ESABALT system based on pre-defined user profile groups. These requirements have been identified through multiple sources, which include an electronic survey of potential users of the system, interviews with specialists in navigation, law and computer science, analysis of state-of-the-art in maritime safety procedures, and study of past R&D projects in this field. Finally, these requirements are classified into user level, domain level and system level requirements for easy interpretation while designing the system architecture and its function-al specifications. The presented system specification is discussed

Immune status of recipients following bone marrow - Augmented solid organ transplantation

It has been postulated that the resident “passenger” leukocytes of hematolymphoid origin that migrate from whole organ grafts and subsequently establish systemic chimerism are essential for graft acceptance and the induction of donor-specific nonreactivity. This phenomenon was augmented by infusing 3 × 108 unmodified donor bone-marrow cells into 40 patients at the time of organ transplantation. Fifteen of the first 18 analyzable patients had sequential immunological evaluation over postoperative intervals of 5 to 17 months, (which included 7 kidney (two with islets), 7 liver (one with islets), and one heart recipient). The evolution of changes was compared with that in 16 kidney and liver nonmarrow controls followed for 4 to5 months. The generic immune reactivity of peripheral blood mononuclear cells (PBMC) was determined by their proliferative responses to mitogens (PHA, ConA). Alloreactivity was measured by the recipient mixed lymphocyte reaction (MLR) to donor and HLA-mis-matched third-party panel cells. Based on all 3 tests,the recipients were classified as donor-specific hyporeactive, intermediate, and responsive; patients who were globally suppressed made up a fourth category. Eight (53%) of the 15 marrow-treated recipients exhibited progressive modulation of donor-specific reactivity (3 hyporeactive and 5 intermediate) while 7 remained antidonor-responsive. In the nonmarrow controls, 2 (12.5%) of the 16 patients showed donor-specific hyporeactivity, 10 (62.5%) were reactive, and 4 (25%) studied during a CMV infection had global suppression of responsiveness to all stimuli. © 1995 by Williams and Wilkins

Supernova Remnants Associated with Molecular Clouds in the Large Magellanic Cloud

We used the Swedish-ESO Submillimeter Telescope (SEST) to search for CO emission associated with three supernova remnants (SNRs) in the Large Magellanic Cloud: N49, N132D, and N23. Observations were carried out in the J=2-1 rotational transition of CO (230.5 GHz) where the half power beamwidth of the SEST is 23". Molecular clouds were discovered near N49 and N132D; no CO emission was discovered in the region we mapped near N23. The N49 cloud has a peak line temperature of 0.75 K, spatial scale of ~7 pc and virial mass of ~30,000 solar masses. The N132D cloud is brighter with a peak temperature of 5 K; it is also larger ~22 pc and considerably more massive 200,000 solar masses. The velocities derived for the clouds near N49 and N132D, +286.0 km/s and +264.0 km/s, agree well with the previously known velocities of the associated SNRs: +286 km/s and +268 km/s, respectively. ROSAT X-ray images show that the ambient density into which the remnants are expanding appears to be significantly increased in the direction of the clouds. Taken together these observations indicate a physical association between the remnants and their respective, presumably natal, molecular clouds. The association of N49 and N132D with dense regions of molecular material means that both were likely products of short-lived progenitors that exploded as core-collapse supernovae.Comment: 26 pages, including 9 postscript figs, LaTeX (includes aaspp.sty), accepted by Ap.J. for vol 480, May 10, 199

Relativistic quantum dynamics in strong fields: Photon emission from heavy, few-electron ions

Recent progress in the study of the photon emission from highly-charged heavy ions is reviewed. These investigations show that high-$Z$ ions provide a unique tool for improving the understanding of the electron-electron and electron-photon interaction in the presence of strong fields. Apart from the bound-state transitions, which are accurately described in the framework of Quantum Electrodynamics, much information has been obtained also from the radiative capture of (quasi-) free electrons by high-$Z$ ions. Many features in the observed spectra hereby confirm the inherently relativistic behavior of even the simplest compound quantum systems in Nature.Comment: Version 18/11/0