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Standard Configuration (standard + configuration)

Distribution by Scientific Domains

Physics and Astronomy	75%

Selected Abstracts

ECCD Experiments Using the Upgraded Launching System in Heliotron J

CONTRIBUTIONS TO PLASMA PHYSICS, Issue 6-7 2010
K. Nagasaki
Abstract Electron cyclotron current drive (ECCD) experiments have been made in Heliotron J by using an upgraded EC launching system. A focused Gaussian beam is injected with the parallel refractive index, N||, ranging from -0.05 to 0.6. Ray tracing calculation shows that the EC power is more localized than that in the previous launching system. In the initial ECCD experiment, the EC injection angle has been successfully scanned as designed. Comparison between perpendicular and oblique launching experiments shows that for standard configuration, the EC current of 1 kA is driven at N|| , 0.3 in the Fisch-Boozer direction, and the bootstrap current flows up to 1 kA. A large increase in electron cyclotron emission (ECE) signals has been observed when the EC current was driven (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Optical turbulence vertical distribution with standard and high resolution at Mt Graham

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2010
E. Masciadri
ABSTRACT A characterization of the optical turbulence vertical distribution (C2N profiles) and all the main integrated astroclimatic parameters derived from the C2N and the wind speed profiles above the site of the Large Binocular Telescope (LBT) (Mt Graham, Arizona, USA) is presented. The statistics include measurements related to 43 nights done with a Generalized SCIDAR (GS) used in standard configuration with a vertical resolution ,H, 1 km on the whole 20 km and with the new technique (High Vertical Resolution GS) in the first kilometre. The latter achieves a resolution ,H, 20,30 m in this region of the atmosphere. Measurements done in different periods of the year permit us to provide a seasonal variation analysis of the C2N. A discretized distribution of C2N, useful for the Ground Layer Adaptive Optics (GLAO) simulations, is provided and a specific analysis for the LBT Laser Guide Star system ARGOS (running in GLAO configuration) case is done including the calculation of the ,grey zones' for J, H and K bands. Mt Graham is confirmed to be an excellent site with median values of the seeing without dome contribution ,= 0.72 arcsec, the isoplanatic angle ,0= 2.5 arcsec and the wavefront coherence time ,0= 4.8 ms. We find that the OT vertical distribution decreases in a much sharper way than what has been believed so far in the proximity of the ground above astronomical sites. We find that 50 per cent of the whole turbulence develops in the first 80 ± 15 m from the ground. We finally prove that the error in the normalization of the scintillation that has been recently demonstrated in the principle of the GS technique affects these measurements by an absolutely negligible quantity (0.04 arcsec). [source]

Using a Discrete-event Simulation to Balance Ambulance Availability and Demand in Static Deployment Systems

ACADEMIC EMERGENCY MEDICINE, Issue 12 2009
Ching-Han Wu EMT-P
Abstract Objectives:, To improve ambulance response time, matching ambulance availability with the emergency demand is crucial. To maintain the standard of 90% of response times within 9 minutes, the authors introduce a discrete-event simulation method to estimate the threshold for expanding the ambulance fleet when demand increases and to find the optimal dispatching strategies when provisional events create temporary decreases in ambulance availability. Methods:, The simulation model was developed with information from the literature. Although the development was theoretical, the model was validated on the emergency medical services (EMS) system of Tainan City. The data are divided: one part is for model development, and the other for validation. For increasing demand, the effect was modeled on response time when call arrival rates increased. For temporary availability decreases, the authors simulated all possible alternatives of ambulance deployment in accordance with the number of out-of-routine-duty ambulances and the durations of three types of mass gatherings: marathon races (06:00,10:00 hr), rock concerts (18:00,22:00 hr), and New Year's Eve parties (20:00,01:00 hr). Results:, Statistical analysis confirmed that the model reasonably represented the actual Tainan EMS system. The response-time standard could not be reached when the incremental ratio of call arrivals exceeded 56%, which is the threshold for the Tainan EMS system to expand its ambulance fleet. When provisional events created temporary availability decreases, the Tainan EMS system could spare at most two ambulances from the standard configuration, except between 20:00 and 01:00, when it could spare three. The model also demonstrated that the current Tainan EMS has two excess ambulances that could be dropped. The authors suggest dispatching strategies to minimize the response times in routine daily emergencies. Conclusions:, Strategies of capacity management based on this model improved response times. The more ambulances that are out of routine duty, the better the performance of the optimal strategies that are based on this model. [source]

Fast measurements of photoreflectance spectra by using multi-channel detector

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 5 2009
R. Kudrawiec
Abstract Photoreflectance (PR) measurements were performed on GaAs- and GaN-based structures in the so called ,bright configuration' where the sample was illuminated by white light (probing beam) instead of monochromatic light as it takes place in the standard configuration, i.e., so-called ,dark configuration'. Within this concept the whole PR spectrum can be measured/processed at the same time using a multi-channel detector (i.e., CCD camera) instead the phase sensitive lock-in detection system with the one-channel detector. In this work PR spectra for Si ,-doped GaAs structure have been measured using both the CCD detector system as well as the standard lock-in technique with the one-channel detector system. GaAs-related Franz,Keldysh oscillations, which are typical of Si ,-doped GaAs structure, have been clearly observed in PR spectra measured by using the two detection systems. In addition, the PR system with the CCD detector has been used to measure PR spectra in the UV spectral region for an InGaN/GaN/Al2O3 structure. In this case, PR resonances related to InGaN and GaN band gap absorption have been clearly observed. Using the PR system with CCD detector the time of PR measurements was reduced to few seconds for both GaAs- and GaN-based structures. It shows that the bright configuration of PR set-up with multi-channel detection system is very promising and perspective in the fast diagnostic of semiconductor structures. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]