The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Yamamoto H. - One of the best experts on this subject based on the ideXlab platform.

  • Determination of the Light exposure on the photodiodes of a new instrumented baffle for the Virgo input mode cleaner end-mirror
    2021
    Co-Authors: Romero A., Allocca A., Chiummo A., Martinez M., Mir, Ll. M., Yamamoto H.
    Abstract:

    As part of the upgrade program of the Advanced Virgo interferometer, the installation of new instrumented baffles surrounding the main test masses is foreseen. As a demonstrator, and to validate the technology, the existing baffle in the area of the input mode cleaner end-mirror will be first replaced by a baffle equipped with photodiodes. This paper presents detailed simulations of the Light Distribution on the input mode cleaner baffle, with the aim to determine the Light exposure of the photodiodes under different scenarios of the interferometer operation.Comment: 9 pages and 8 figure

  • Determination of the Light exposure on the photodiodes of a new instrumented baffle for the Virgo input mode cleaner end-mirror
    'AIP Publishing', 2021
    Co-Authors: Romero-rodríguez A., Allocca A., Chiummo A., Martinez M., Mir, Ll. M., Yamamoto H.
    Abstract:

    As part of the upgrade program of the advanced Virgo interferometer, the installation of new instrumented baffles surrounding the main test masses is foreseen. As a demonstrator, and to validate the technology, the existing baffle in the area of the input mode cleaner end-mirror will be first replaced by a baffle equipped with photodiodes. This paper presents detailed simulations of the Light Distribution on the input mode cleaner baffle. They served to validate the proposed layout of the sensors in the baffle, and determine the Light exposure of the photodiodes under different scenarios of the interferometer operations, in order to define mitigation strategies for preserving the detector integrity

Jeremy D Rogers - One of the best experts on this subject based on the ideXlab platform.

P Sanchezblazquez - One of the best experts on this subject based on the ideXlab platform.

  • the origin of the Light Distribution in spiral galaxies
    Monthly Notices of the Royal Astronomical Society, 2009
    Co-Authors: P Sanchezblazquez, Stephanie Courty, Brad K Gibson, Chris B Brook
    Abstract:

    We analyse a high-resolution, fully cosmological, hydrodynamical disc galaxy simulation, to study the source of the double-exponential Light profiles seen in many stellar discs, and the effects of stellar radial migration upon the spatiotemporal evolution of both the disc age and metallicity Distributions. We find a ‘break’ in the pure exponential stellar surface brightness profile, and trace its origin to a sharp decrease in the star formation per unit surface area, itself produced by a decrease in the gas volume density due to a warping of the gas disc. Star formation in the disc continues well beyond the break. We find that the break is more pronounced in bluer wavebands. By contrast, we find little or no break in the mass density profile. This is, in part, due to the net radial migration of stars towards the external parts of the disc. Beyond the break radius, we find that ∼60 per cent of the resident stars migrated from the inner disc, while ∼25 per cent formed in situ. Our simulated galaxy also has a minimum in the age profile at the break radius but, in disagreement with some previous studies, migration is not the main mechanism producing this shape. In our simulation, the disc metallicity gradient flattens with time, consistent with an ‘inside-out’ formation scenario. We do not find any difference in the intensity or the position of the break with inclination, suggesting that perhaps the differences found in empirical studies are driven by dust extinction.

Yaw Yvonne De Kort - One of the best experts on this subject based on the ideXlab platform.

  • Light Distribution in dynamic street Lighting two experimental studies on its effects on perceived safety prospect concealment and escape
    Journal of Environmental Psychology, 2012
    Co-Authors: Antal A Haans, Yaw Yvonne De Kort
    Abstract:

    The relationship between Light and perceived safety at night is intuitively strong, yet theoretically and empirically its workings are largely unknown. Intelligent dynamic road Lighting, which continuously adapts to the presence and behavior of users, can Light the street only when and where it is needed. As such, it offers a solution to the energy waste and luminous pollution associated with conventional road Lighting. With this innovation, however, new questions emerge about the effect of Lighting on perceived safety. We need to consider not only how much Lighting pedestrians need to feel safe, but also which parts of the street should be lit. In two experiments, we investigated the effect of different Light Distributions on perceived safety, and explored mediation by people’s appraisal of three safety-related cues suggested in the literature: prospect (having an overview), escape (perceived escape possibilities), and refuge/concealment (perceived hiding places for offenders). Both experiments, one with stationary and one with walking participants, demonstrated that people prefer having Light in their own immediate surroundings rather than on the road that lies ahead. This could be explained, partially, by changes in prospect, escape, and concealment. Against expectations, prospect was higher with Lighting Distributions in which participants’ immediate surroundings, but not the more distant parts of the road, were most strongly lit. 2012 Elsevier Ltd. All rights reserved.

Willem M Star - One of the best experts on this subject based on the ideXlab platform.

  • integrating sphere effect in whole bladder wall photodynamic therapy iii fluence multiplication optical penetration and Light Distribution with an eccentric source for human bladder optical properties
    Physics in Medicine and Biology, 1996
    Co-Authors: H J Van Staveren, Marleen Keijzer, T Keesmaat, Harald Jansen, W Kirkel, J F Beek, Willem M Star
    Abstract:

    Whole-bladder-wall (WBW) photodynamic therapy (PDT) is performed using nm Light emitted by an isotropic Light source centred in the bladder cavity. The phenomenon of an increased fluence rate in this spherical geometry, due to Light scattering, is denoted as the integrating sphere effect. The fluence rate and the optical penetration depth depend on a single tissue optical parameter, namely the reduced albedo. The optical properties of (diseased) human bladder tissue, i.e. absorption coefficient, scattering coefficient, anisotropy factor and refractive index, were determined in vitro in the wavelength range of 450 - 800 nm. The integrating sphere effect and optical penetration depth were calculated with diffusion theory and compared to Monte Carlo (MC) computer simulations using nm optical properties. With increasing albedo, the integrating sphere effect calculated with diffusion approximation is increasingly larger than that found with MC simulations. Calculated and simulated optical penetration depths are in reasonable agreement. The smaller the integrating sphere effect for a given tissue absorption, the larger the optical penetration depth into the bladder wall, as the effective attenuation coefficient decreases. Optical penetration depths up to mm (definition dependent) can be responsible for unintended tissue damage beyond the bladder tissue. MC simulations were also performed with an eccentric Light source and the uniformity of the Light Distribution at the bladder wall was assessed. The simulations show that even for a small eccentricity, the extremes in deviation from the mean fluence rate are large. All these results indicate that WBW PDT should be performed with some kind of in situ Light dosimetry.