Spacelab software development and integration concepts study report, volume 1

The proposed software guidelines to be followed by the European Space Research Organization in the development of software for the Spacelab being developed for use as a payload for the space shuttle are documented. Concepts, techniques, and tools needed to assure the success of a programming project are defined as they relate to operation of the data management subsystem, support of experiments and space applications, use with ground support equipment, and for integration testing

Initial development of an ablative leading edge for the space shuttle orbiter

A state-of-the-art preliminary design for typical wing areas is developed. Seven medium-density ablators (with/without honeycomb, flown on Apollo, Prime, X15A2) are evaluated. The screening tests include: (1) leading-edge models sequentially subjected to ascent heating, cold soak, entry heating, post-entry pressure fluctuations, and touchdown shock, and (2) virgin/charred models subjected to bondline strains. Two honeycomb reinforced 30 pcf elastomeric ablators were selected. Roughness/recession degradation of low speed aerodynamics appears acceptable. The design, including attachments, substructure and joints, is presented

Airy beam induced optical routing

We present an all-optical routing scheme based simultaneously on optically induced photonic structures and the Airy beam family. The presented work utilizes these accelerating beams for the demonstration of an all-optical router with individually addressable output channels. In addition, we are able to activate multiple channels at the same time providing us with an optically induced splitter with configurable outputs. The experimental results are corroborated by corresponding numerical simulations

Validation of stellar population and kinematical analysis of galaxies

3D spectroscopy produces hundreds of spectra from which maps of the characteristics of stellar populations (age-metallicity) and internal kinematics of galaxies can be derived. We carried on simulations to assess the reliability of inversion methods and to define the requirements for future observations. We quantify the biases and show that to minimize the errors on the kinematics, age and metallicity (in a given observing time) the size of the spatial elements and the spectral dispersion should be chosen to obtain an instrumental velocity dispersion comparable to the physical dispersion.Comment: 5 pages, 3 figures, extended version of a poster proceeding to appear in "Science Perspectives for 3D Spectroscopy", eds. M. Kissler-Patig, M. M. Roth and J. R. Walsh, ESO Astrophysics Symposia. (The two last pages with figures are not in the conference proceedings.

Annual and interannual variations of Earth-emitted radiation based on a 10-year data set

The method of empirical orthogonal functions (EOF) was applied to a 10-year data set of outgoing longwave radiation. Spherical harmonic functions are used as a basis set for producing equal area map results. The following findings are noted. The first EOF accounts for 66 percent of the variance. After that, each EOF accounts for only a small variance, forming a slowly converging series. The first two EOF's describe mainly the annual cycle. The third EOF is primarily the semiannual cycle although many other EOF's also contain significant semiannual parts. These results reaffirm those based on a shorter data set. In addition, a much stronger spring/fall mode was found in the central equatorial Pacific Ocean for the second EOF than was found earlier. This difference is attributed to the use of broadband radiometer data which were available for the present study. The earlier study used data from a window channel instrument which is not as sensitive to water vapor variations. The fourth EOF describes much of the 1976 to 1977 and 1982 to 1983 ENSO phenomena. There is typically a gap in the spectrum between a semiannual peak and the annual cycle for all but the first EOF. A semiannual OLR dipole straddles the Asian-Australian monsoon track

Exchange Rate Policy in Small Rich Economies

We look at the exchange rate policy choices and outcomes for small rich economies. Small rich economies face significant policy challenges due to proportionately greater economic volatility than larger economies. These economies usually choose some form of fixed exchange rate regime, particularly in the very small economies where the per capita cost of independent monetary policy is relatively high. When such countries do choose a free or managed floating regime, they appear to derive no benefit from those regimes; their exchange rate volatility seems to rise without any significant change in fundamental economic volatility. Thus, for these countries, floating exchange rates seem to create problems for policy makers without solving any.Small economies, Exchange rate regimes

Parametrization of the angular correlation and degree of linear polarization in two-photon decays of hydrogen-like ions

The two-photon decay in hydrogen-like ions is investigated within the framework of second order perturbation theory and Dirac's relativistic equation. Special attention is paid to the angular correlation of the emitted photons as well as to the degree of linear polarization of one of the two photons, if the second is just observed under given angles. Expressions for the angular correlation and the degree of linear polarization are expanded in terms of $\cos\theta$-polynomials, whose coefficients depend on the atomic number and the energy sharing of the emitted photons. The effects of including higher (electric and magnetic) multipoles upon the emitted photon pairs beyond the electric-dipole approximation are also discussed. Calculations of the coefficients are performed for the transitions $2s_{1/2}\rightarrow1s_{1/2}$, $3d_{3/2}\rightarrow1s_{1/2}$ and $3d_{5/2}\rightarrow1s_{1/2}$, along the entire hydrogen isoelectronic sequence ($1\le Z \le 100$)

Angular Correlations in Internal Pair Conversion of Aligned Heavy Nuclei

We calculate the spatial correlation of electrons and positrons emitted by internal pair conversion of Coulomb excited nuclei in heavy ion collisions. The alignment or polarization of the nucleus results in an anisotropic emission of the electron-positron pairs which is closely related to the anisotropic emission of $\gamma$-rays. However, the angular correlation in the case of internal pair conversion exhibits diverse patterns. This might be relevant when investigating atomic processes in heavy-ion collisions performed at the Coulomb barrier.Comment: 27 pages + 6 eps figures, uses revtex.sty and epsf.sty, tar-compressed and uuencoded with uufile