PASP Plus: An experiment to measure space-environment effects on photovoltaic power subsystems

The Photovoltaic Array Space Power Plus Diagnostic experiment (PASP Plus) was accepted as part of the APEX Mission payload aboard a Pegastar satellite to be orbited by a Pegasus launch vehicle in late 1992. The mission's elliptical orbit will allow us to investigate both space plasma and space radiation effects. PASP Plus will have eleven types of solar arrays and a full complement of environmental and interactions diagnostic sensors. Measurements of space-plasma interactions on the various solar arrays will be made at large negative voltages (to investigate arcing parameters) and at large positive voltages (to investigate leakage currents) by biasing the arrays to various levels up to -500 and +500 volts. The long-term deterioration in solar array performance caused by exposure to space radiation will also be investigated; radiation dosage will be measured by an electron/proton dosimeter included in the environmental sensor complement. Experimental results from PASP Plus will help establish cause-and-effect relationships and lead to improved design guidelines and test standards for new-technology solar arrays

Numerical program for analysis of three-dimensional supersonic exhaust flow fields (CHAR 3D)

Choice of reference plane orientation depends on specific nozzle geometry, with different configurations requiring different reference plane systems. In addition, for given configuration several reference systems may be used in different regions of flow field, so each system is locally aligned with flow

Interactions measurement payload for Shuttle

The Interactions Measurement Payload for Shuttle (IMPS) consisted of engineering experiments to determine the effects of the space environment on projected Air Force space systems. Measurements by IMPS on a polar-orbit Shuttle flight will lead to detailed knowledge of the interaction of the low-altitude polar-auroral environment on materials, equipment and technologies to be used in future large, high-power space systems. The results from the IMPS measurements will provide direct input to MIL-STD design guidelines and test standards that properly account for space-environment effects

Measurement of high-voltage and radiation-damage limitations to advanced solar array performance

A description is given of the reconfigured Photovoltaic Array Space Power (PASP) Plus experiment: its objectives, solar-array complement, and diagnostic sensors. Results from a successful spaceflight will lead to a better understanding of high-voltage and radiation-damage limitations in the operation of new-technology solar arrays

Evolution de l'ajustement gestuel au destinataire (sourd/entendant) en tâche de communication référentielle.

International audienceIn a face-to-face referential communication task, adult speakers were associated with two listeners in succession: one normal-hearing average adult, and a profoundly deaf oralizing adult, both accomplices of the experimenter. Each speaker described letter composed of geometric elements. The listener had to build the figure as the speaker described the location of each of the elements. The desktop of both interlocutors was hidden by a screen. It was hypothesized that as soon as the speaker realized that the deaf listener was having problems, he or she would take greater advantage of the gestural channel. The results showed that semantic (iconic and deictic) gestures were widely used by both types of dyads. However, speakers faced with a deaf listener used them more. The gestures were wide in extent throughout the entire duration of the exchange

Can the Supersymmetric μ\mu parameter be generated dynamically without a light Singlet?

It is generally assumed that the dynamical generation of the Higgs mass parameter of the superpotential, $\mu$, implies the existence of a light singlet at or below the supersymmetry breaking scale, \msusy. We present a counter-example in which the singlet field can receive an arbitrarily heavy mass (\eg, of the order of the Planck scale, M_{\rm P}\approx 10^{19}~\gev). In this example, a non-zero value of $\mu$ is generated through soft supersymmetry breaking parameters and is thus naturally of the order of \msusy.Comment: 6 pages, phyzzx, DESY 94-06

Nonlinear Transient Field Problems with Phase Change using the Boundary Element Method

Peer reviewe

Modelling macroscopic and baby universes by fundamental strings

We develop a model of $(1+1)$-dimensional parent and baby universes as macroscopic and microscopic fundamental closed strings. We argue, on the basis of understanding of strings from the point of view of target $D$-dimensional space-time, that processes involving baby universes/wormholes not only induce $c$-number "$\alpha$-parameters" in $(1+1)d$ action, but also lead to loss of quantum coherence for a $(1+1)d$ observer in the parent universe.Comment: 21 pages, LaTeX, no figure

Effects of TeV Scale Gravity on e^+e^- --> W^+ W^-

We study the process e^+e^- --> W^+W^- to probe low-scale gravity at high energy linear colliders. A characteristic signature of extra-dimensions models is the forward-backward asymmetry due to the interference of spin-2 graviton and spin-1 SM gauge boson exchange terms, even when right-polarised electron beam is used. Our analysis shows that larger than 5% asymmetry is possible at a linear collider with \sqrt{s}=500 (800) GeV if the mass scale, M_S is smaller than 2.7 (4.5) TeV. W^- polarisation factors measured with a few percent accuracy will also be able to put similar limits on M_S.Comment: 8 pages including figure

Nonanomalous R-symmetry in supersymmetric unified theories of quarks and leptons

A discrete R-symmetry often appears as an exact gauge symmetry in the low energy effective theory of superstring theories. We search for such discrete R-symmetries from a phenomenological point of view and find that Z_{9R} and Z_{18R} are candidates of the nonanomalous R-symmetry in the case of the minimal supersymmetric standard model. We also find Z_{4R} and Z_{20R} in the case that quarks and leptons are embedded in the SU(5) GUT multiplets. Interesting is that in the latter case all the solutions predict some extra matter multiplets and we find that the simplest choice is to take a pair of {\bf 5} and {\bf 5}^* of SU(5)_{GUT} whose mass is of order the SUSY breaking scale \sim 1 TeV. We emphasize that the presence of such extra matters is testable in future collider experiments.Comment: 15 pages, LaTeX, no figure