293 research outputs found
Design and Preliminary Testing of Demand-Responsive Transverse Rumble Strips
Transverse rumble strips are common practice to alert drivers by engaging their auditory and tactile senses in addition to visual senses by traffic signals. However, continuous exposure to noise and vibration by transverse rumble strips often results in diminished effectiveness and erratic behaviors, leading to additional safety challenges. In response, demand-responsive transverse rumble strips were developed as traffic safety countermeasures that reduce unnecessary noise and vibration associated with transverse rumble strips by incorporating active control of the rumble strips. Rather than staying static, demand-responsive transverse rumble strips are activated based on the presence of pedestrians, at predesignated times, or in response to abrupt changes in traffic flow. To evaluate the effectiveness of demand-responsive transverse rumble strips, the research team assessed noise and vibration data, both inside the vehicles and on the roadside, for various types of vehicles traveling at different speeds. The test data indicate that demand-responsive transverse rumble strips produced noticeable in-vehicle noise and vibration that could alert drivers to downstream events. Furthermore, demand-responsive transverse rumble strips generated sufficient noise to alert roadside pedestrians to vehicle presence but at low enough level to be considered as acceptable for a residential neighborhood use. Accordingly, demand-responsive transverse rumble strips could address the challenges that static transverse rumble strips face, by providing a design with relatively limited noise while enhancing safety
Prospects for identifying the sources of the Galactic cosmic rays with IceCube
We quantitatively address whether IceCube, a kilometer-scale neutrino
detector under construction at the South Pole, can observe neutrinos pointing
back at the accelerators of the Galactic cosmic rays. The photon flux from
candidate sources identified by the Milagro detector in a survey of the TeV sky
is consistent with the flux expected from a typical cosmic-ray generating
supernova remnant interacting with the interstellar medium. We show here that
IceCube can provide incontrovertible evidence of cosmic-ray acceleration in
these sources by detecting neutrinos. We find that the signal is optimally
identified by specializing to events with energies above 30 TeV where the
atmospheric neutrino background is low. We conclude that evidence for a
correlation between the Milagro and IceCube sky maps should be conclusive after
several years.Comment: 5 pages, 5 figures; part of the text and some figures have changed,
conclusions remain the same; equals journal versio
Potential Neutrino Signals from Galactic Gamma-Ray Sources
The recent progress made in Galactic gamma-ray astronomy using the High
Energy Stereoskopic System (H.E.S.S.) instrument provides for the first time a
population of Galactic TeV gamma-rays, and hence potential neutrino sources,
for which the neutrino flux can be estimated. Using the energy spectra and
source morphologies measured by H.E.S.S., together with new parameterisations
of pion production and decay in hadronic interactions, we estimate the signal
and background rates expected for these sources in a first-generation water
Cherenkov detector (ANTARES) and a next-generation neutrino telescope in the
Mediterranean Sea, KM3NeT, with an instrumented volume of 1 km^3. We find that
the brightest gamma-ray sources produce neutrino rates above 1 TeV, comparable
to the background from atmospheric neutrinos. The expected event rates of the
brightest sources in the ANTARES detector make a detection unlikely. However,
for a 1 km^3 KM3NeT detector, event rates of a few neutrinos per year from
these sources are expected, and the detection of individual sources seems
possible. Although generally these estimates should be taken as flux upper
limits, we discuss the conditions and type of gamma-ray sources for which the
neutrino flux predictions can be considered robust.Comment: 20 pages, 4 figures; v2: ERROR in energy scale of KM3NeT effective
neutrino area corrected which resulted in event rates being about a factor 3
too low; v3: grammatical changes and update of references after receiving
proof
AHO-Heft 9 : Eine Synopse der 4. und 5. Auflage
Die nachfolgende Synopse macht die Änderungen zwischen Heft 4 und Heft 5 sichtbar und ist eine Handreichung, die nicht nur die Entwicklung der Leistungsbilder verdeutlicht, sondern insbesondere eine Hilfestellung für die Angebotserstellung und die Ausführung der Leistungen sein kann. Zunächst werden die Grundleistungen vergleichend gegenübergestellt. Danach werden pro Handlungsbereich die Grundleistungen projektchronologisch hintereinander folgend dargestellt. Es folgt der synoptische Vergleich der Projektleitungsleistungen. Den Abschluss bildet die Gegenüberstellung der Mitwirkungshandlungen des Auftraggebers. Eine Veröffentlichung des DVP - Deutscher Verband für Projektmanagement in der Bau-und Immobilienwirtschaft e. V
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