9,089 research outputs found
Study of guidance techniques for aerial application of agricultural compounds
Candidate systems were identified for evaluation of suitability in meeting specified accuracy requirements for a swath guidance system in an agriculture aircraft. Further examination reduced the list of potential candidates to a single category, i.e., transponder type systems, for detailed evaluation. Within this category three systems were found which met the basic accuracy requirements of the work statement. The Flying Flagman, the Electronic Flagging and the Raydist Director System. In addition to evaluating the systems against the specified requirements, each system was compared with the other two systems on a relative basis. The conclusions supported by the analyses show the Flying Flagman system to be the most suitable system currently available to meet the requirements
Pulse shape simulation for segmented true-coaxial HPGe detectors
A new package to simulate the formation of electrical pulses in segmented
true-coaxial high purity germanium detectors is presented. The computation of
the electric field and weighting potentials inside the detector as well as of
the trajectories of the charge carriers is described. In addition, the
treatment of bandwidth limitations and noise are discussed. Comparison of
simulated to measured pulses, obtained from an 18-fold segmented detector
operated inside a cryogenic test facility, are presented.Comment: 20 pages, 16 figure
The construction of a social studies vocabulary test for teachers in training.
Thesis (Ed.M.)--Boston Universit
Analogy, Dirac-Majorana Neutrino Duality and the Neutrino Oscillations
The intent of this paper is to convey a new primary physical idea of a
Dirac-Majorana neutrino duality in relation to the topical problem of neutrino
oscillations. In view of the new atmospheric, solar and the LSND neutrino
oscillation data, the Pontecorvo oscillation analogy is generalized
to the notion of neutrino duality with substantially different physical meaning
ascribed to the long-baseline and the short-baseline neutrino oscillations. At
the level of CP-invariance, the suggestion of dual neutrino properties defines
the symmetric two-mixing-angle form of the widely discussed four-neutrino
-mixing scheme, as a result of the lepton charge conservation selection
rule and a minimum of two Dirac neutrino fields. With neutrino duality, the
two-doublet structure of the Majorana neutrino mass spectrum is a vestige of
the two-Dirac-neutrino origin. The fine neutrino mass doublet structure is
natural because it is produced by a lepton charge symmetry violating
perturbation on a zero-approximation system of two twofold mass-degenerate
Dirac neutrino-antineutrino pairs. A set of inferences related to the neutrino
oscillation phenomenology in vacuum is considered.Comment: 13 pages, LaTeX. Minor modifications, new references adde
Quantum Creation of Topological Black Hole
The constrained instanton method is used to study quantum creation of a
vacuum or charged topological black hole. At the level, the relative
creation probability is the exponential of a quarter sum of the horizon areas
associated with the seed instanton.Comment: Report-no change onl
Large Angular Scale CMB Anisotropy Induced by Cosmic Strings
We simulate the anisotropy in the cosmic microwave background (CMB) induced
by cosmic strings. By numerically evolving a network of cosmic strings we
generate full-sky CMB temperature anisotropy maps. Based on maps, we
compute the anisotropy power spectrum for multipole moments . By
comparing with the observed temperature anisotropy, we set the normalization
for the cosmic string mass-per-unit-length , obtaining , which is consistent with all other
observational constraints on cosmic strings. We demonstrate that the anisotropy
pattern is consistent with a Gaussian random field on large angular scales.Comment: 4 pages, RevTeX, two postscript files, also available at
http://www.damtp.cam.ac.uk/user/defects/ to appear in Physical Review
Letters, 23 September 199
Dynamic Black-Level Correction and Artifact Flagging in the Kepler Data Pipeline
Instrument-induced artifacts in the raw Kepler pixel data include time-varying crosstalk from the fine guidance sensor (FGS) clock signals, manifestations of drifting moir pattern as locally correlated nonstationary noise and rolling bands in the images which find their way into the calibrated pixel time series and ultimately into the calibrated target flux time series. Using a combination of raw science pixel data, full frame images, reverse-clocked pixel data and ancillary temperature data the Keplerpipeline models and removes the FGS crosstalk artifacts by dynamically adjusting the black level correction. By examining the residuals to the model fits, the pipeline detects and flags spatial regions and time intervals of strong time-varying blacklevel (rolling bands ) on a per row per cadence basis. These flags are made available to downstream users of the data since the uncorrected rolling band artifacts could complicate processing or lead to misinterpretation of instrument behavior as stellar. This model fitting and artifact flagging is performed within the new stand-alone pipeline model called Dynablack. We discuss the implementation of Dynablack in the Kepler data pipeline and present results regarding the improvement in calibrated pixels and the expected improvement in cotrending performances as a result of including FGS corrections in the calibration. We also discuss the effectiveness of the rolling band flagging for downstream users and illustrate with some affected light curves
- …