3,378 research outputs found
Electrostatic Characterization of Lunar Dust Simulants
Lunar dust can jeopardize exploration activities due to its ability to cling to most surfaces. In this paper, we report on our measurements of the electrostatic properties of the lunar soil simulants. Methods have been developed to measure the volume resistivity, dielectric constant, chargeability, and charge decay of lunar soil. While the first two parameters have been measured in the past [Olhoeft 1974], the last two have never been measured directly on the lunar regolith or on any of the Apollo samples. Measurements of the electrical properties of the lunar samples are being performed in an attempt to answer important problems that must be solved for the development of an effective dust mitigation technology, namely, how much charge can accumulate on the dust and how long does the charge remain on surfaces. The measurements will help develop coatings that are compatible with the intrinsic electrostatic properties of the lunar regolith
Sensitivity to new supersymmetric thresholds through flavour and CP violating physics
Treating the MSSM as an effective theory below a threshold scale Lambda, we
study the consequences of having dimension-five operators in the superpotential
for flavour and CP-violating processes. Below the supersymmetric threshold such
terms generate flavour changing and/or CP-odd effective operators of dimension
six composed from the Standard Model fermions, that have the interesting
property of decoupling linearly with the threshold scale, i.e. as 1/(Lambda
m_soft), where m_soft is the scale of soft supersymmetry breaking. The
assumption of weak-scale supersymmetry, together with the stringent limits on
electric dipole moments and lepton flavour-violating processes, then provides
sensitivity to Lambda as high as 10^7-10^9 GeV. We discuss the varying
sensitivity to these scales within several MSSM benchmark scenarios and also
outline the classes of UV physics which could generate these operators.Comment: 28 pages, 9 figure
A new model for magnetoreception
Certain migratory birds can sense the earth's magnetic field. The nature of
this process is not yet properly understood. Here we offer a simple explanation
according to which birds literally `see' the local magnetic field: Our model
relates the well-established radical pair hypothesis to the phenomenon of
Haidinger's brush, a capacity to see the polarisation of light. This new
picture explains recent surprising experimental data indicating long lifetimes
for the radical pair. Moreover there is a clear evolutionary path toward this
field sensing mechanism: it is an enhancement of a weak effect that may be
present in many species.Comment: 8 pages, 5 figures, version of final published pape
Scoping biological indicators of soil quality Phase II. Defra Final Contract Report SP0534
This report presents results from a field assessment of a limited suite of potential biological indicators of soil quality to investigate their suitability for national-scale soil monitoring
Delivery of Hands-On Technical Courses Through Real-Time Distance Learning
It is generally believed that it is too challenging to deliver technical laboratory courses using distance learning technologies. The focus of this research was to develop strategies that may be used to address these challenges. A research team composed of faculty from several universities and community colleges explored what might be needed to make these types of technical laboratory course instruction possible using distance learning technologies. The team explored delivering a microcontroller embedded systems design course through audio-visual distance learning technologies. The team\u27s research and development activities are discussed. These include focuses on the technical training equipment that had to be designed to support the course\u27s microcontroller technologies curriculum and laboratory modules, instructional support videos, and the design of an electronic server system to support this instruction. Also discussed will be the findings from the faculty of other colleges and universities who received professional development training from the research team on teaching microcontroller technology courses using distance learning technologies
Physical Constraints in Grassland Ecosystems
Key points
1. Grassland system management must account adequately for biophysical and biochemical processes.
2. Amenity turf, especially sports turf, provides an excellent case study on how biology and physics interact to impact on the functioning of a grass ecosystem.
3. Microorganisms produce hydrophobic compounds that act to decrease water ingress and alter the function of the soil-grass ecosystem
Kindersimulation heute und morgen: Perspektiven und Konzepte
Zusammenfassung: Die Konfrontation mit kritisch kranken Neugeborenen, Säuglingen und Kleinkindern ist selten und stellt ein Behandlungsteam vor besondere Herausforderungen. Für eine erfolgreiche Notfallbehandlung sind sichere technische und nichttechnische Fertigkeiten essenziell. Kindersimulatoren ermöglichen die Schaffung einer didaktischen Infrastruktur zur Vernetzung von Lehrbuchtheorie mit erfahrungsaktiver Praxis. Zur Erfassung des aktuellen Status der Kindersimulation in Deutschland, Österreich und der Schweiz wurde eine Onlinebefragung aller entsprechend aktiven Zentren durchgeführt. Derzeit wird Kindersimulation in 24Zentren betrieben. Diese verfügen über 39 pädiatrische Simulatoren: 8 für Neugeborene, 26 für Säuglinge und 5 für Kinder. Eine gewisse Kongruenz im Standard ist unter den Zentren feststellbar. Die meisten Instruktoren verfügen über eine spezialisierte Instruktorenausbildung. Von den Instruktoren sind 26% Pflegefachkräfte und 67% Ärzte, davon haben Pädiater und Anästhesisten den größten Anteil. Viele Zentren (38%) funktionieren lediglich durch das spezielle Engagement ihrer Mitarbeiter, die diverse Aktivitäten in ihrer Freizeit organisieren. Videogestützte Nachbesprechungen gelten als Grundlage für ein effektives Training. Einen besonderen inhaltlichen Schwerpunkt legen fast alle Zentren (92%) auf die Vermittlung von nichttechnischen Fertigkeiten (interpersonelle Aspekte des Zwischenfallmanagements). Im Rahmen des kürzlich etablierten PaedSim-Projekts sollen die Curricula von Kindersimulationskursen noch klarer strukturiert sowie international standardisiert werden, um dadurch Trainingseffektivität und -nachhaltigkeit zu erhöhe
Characteristics of Control Laws Tested on the Semi-Span Super-Sonic Transport (S4T) Wind-Tunnel Model
The Semi-Span Supersonic Transport (S4T) is an aeroelastically scaled wind-tunnel model built to test active controls concepts for large flexible supersonic aircraft in the transonic flight regime. It is one of several models constructed in the 1990's as part of the High Speed Research (HSR) Program. Control laws were developed for the S4T by M4 Engineering, Inc. and by Zona Technologies, Inc. under NASA Research Announcement (NRA) contracts. The model was tested in the NASA-Langley Transonic Dynamics Tunnel (TDT) four times from 2007 to 2010. The first two tests were primarily for plant identification. The third entry was used for testing control laws for Ride Quality Enhancement, Gust Load Alleviation, and Flutter Suppression. Whereas the third entry only tested FS subcritically, the fourth test demonstrated closed-loop operation above the open-loop flutter boundary. The results of the third entry are reported elsewhere. This paper reports on flutter suppression results from the fourth wind-tunnel test. Flutter suppression is seen as a way to provide stability margins while flying at transonic flight conditions without penalizing the primary supersonic cruise design condition. An account is given for how Controller Performance Evaluation (CPE) singular value plots were interpreted with regard to progressing open- or closed-loop to higher dynamic pressures during testing
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