Light source spectrum, brightness perception and visual performance in pedestrian environments: A review

This review considers the impact of light source spectral power distribution (SPD) on brightness perception and visual performance in mesopic conditions, with emphasis on the comparison of metal halide (MH) and high pressure sodium (HPS) lamps. Models of mesopic vision predict that SPD is a significant variable in that at a HPS photopic luminance of 0.100 cd/m, MH need only produce about 0.070-0.075 cd/m to be seen as equally bright. However, attempts to validate the predictions of these models in the field have met with mixed success. As for visual performance, experimentation has shown that there are effects of SPD in mesopic conditions, but the magnitude of these effects depends on the nature of the task. Three alternative approaches are suggested for comparing light sources with different SPDs in mesopic conditions. © The Chartered Institution of Building Services Engineers 2005

Investigating the chromatic contribution to recognition of facial expression

A pedestrian may judge the intentions of another person by their facial expression amongst other cues and aiding such evaluation after dark is one aim of road lighting. Previous studies give mixed conclusions as to whether lamp spectrum affects the ability to make such judgements. An experiment was carried out using conditions better resembling those of pedestrian behaviour, using as targets photographs of actors portraying facial expressions corresponding to the six universally recognised emotions. Responses were sought using a forced-choice procedure, under two types of lamp and with colour and grey scale photographs. Neither lamp type nor image colour was suggested to have a significant effect on the frequency with which the emotion conveyed by facial expression was correctly identified

Isomer shift and magnetic moment of the long-lived 1/2+^{+} isomer in 3079^{79}_{30}Zn49_{49}: signature of shape coexistence near 78^{78}Ni

Collinear laser spectroscopy has been performed on the $^{79}_{30}$Zn$_{49}$ isotope at ISOLDE-CERN. The existence of a long-lived isomer with a few hundred milliseconds half-life was confirmed, and the nuclear spins and moments of the ground and isomeric states in $^{79}$Zn as well as the isomer shift were measured. From the observed hyperfine structures, spins $I = 9/2$ and $I = 1/2$ are firmly assigned to the ground and isomeric states. The magnetic moment $\mu$ ($^{79}$Zn) = $-$1.1866(10) $\mu_{\rm{N}}$, confirms the spin-parity $9/2^{+}$ with a $\nu g_{9/2}^{-1}$ shell-model configuration, in excellent agreement with the prediction from large scale shell-model theories. The magnetic moment $\mu$ ($^{79m}$Zn) = $-$1.0180(12) $\mu_{\rm{N}}$ supports a positive parity for the isomer, with a wave function dominated by a 2h-1p neutron excitation across the $N = 50$ shell gap. The large isomer shift reveals an increase of the intruder isomer mean square charge radius with respect to that of the ground state: $\delta \langle r^{2}_{c}\rangle^{79,79m}$ = +0.204(6) fm$^{2}$, providing first evidence of shape coexistence.Comment: 5 pages, 4 figures, 1 table, Accepeted by Phys. Rev. Lett. (2016

Vegetation in urban streets, squares, and courtyards

One of various ways in which vegetation cover used in the greening of urban areas can help improve the health and well-being of people is in how it changes the acoustic environment. This chapter presents findings of computer simulations and scale modelling to examine and quantify the effectiveness of green roof and green wall (vertical garden) systems in reducing road traffic noise for streets, squares, and roadside courtyards. Noise reduction by sound absorption in reflected and diffracted (over roofs) sound paths is investigated. Particular attention is paid to the importance of vegetation placement relative to the receiver/listening positions. Because the soil substrate used for the vertical walls has good sound absorption properties, it also can be used for green barriers. In this chapter, the effects of a low barrier made of green wall substrate are studied for an installation on the ground and on the top of buildings surrounding a courtyard

Halos and related structures

The halo structure originated in nuclear physics but is now encountered more widely. It appears in loosely bound, clustered systems where the spatial extension of the system is significantly larger than that of the binding potentials. A review is given on our current understanding of these structures, with an emphasis on how the structures evolve as more cluster components are added, and on the experimental situation concerning halo states in light nuclei.Comment: 27 pages, 3 figures, Contribution to Nobel Symposium 152 "Physics With Radioactive Beams

Developments for resonance ionization laser spectroscopy of the heaviest elements at SHIP

The experimental determination of atomic levels and the first ionization potential of the heaviest elements (Z >= 100) is key to challenge theoretical predictions and to reveal changes in the atomic shell structure. These elements are only artificially produced in complete-fusion evaporation reactions at on-line facilities such as the GSI in Darmstadt at a rate of, at most, a few atoms per second. Hence, highly sensitive spectroscopic methods are required. Laser spectroscopy is one of the most powerful and valuable tools to investigate atomic properties. In combination with a buffer-gas filled stopping cell, the Radiation Detected Resonance Ionization Spectroscopy (RADRIS) technique provides the highest sensitivity for laser spectroscopy on the heaviest elements. The RADRIS setup, as well as the measurement procedure, have been optimized and characterized using the a-emitter 155Yb in on-line conditions, resulting in an overall efficiency well above 1%. This paves the way for a successful search of excited atomic levels in nobelium and heavier elements.publisher: Elsevier articletitle: Developments for resonance ionization laser spectroscopy of the heaviest elements at SHIP journaltitle: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms articlelink: http://dx.doi.org/10.1016/j.nimb.2016.06.001 content_type: article copyright: © 2016 Elsevier B.V. All rights reserved.status: publishe

Monitoring the axial displacement of a high-rise building under construction using embedded distributed fibre optic sensors

The floor-to-floor axial shortening of vertical load-bearing elements is an important factor in the design and construction of high-rise buildings. Contractors need to allow for the expected final compression of columns and walls due to superimposed load, concrete creep and shrinkage, particularly when installing finishes and partitions in lower floors, while the building has not yet been completed. An added complication arises from the differential shortening between elements of different stiffness. This axial shortening is predicted by designers using empirical models, in advance of construction. However, in practice, the shortening at every level cannot be measured continuously using traditional surveying measurement techniques during construction. Therefore, a monitoring system using distributed fibre optic sensors (DFOS) measuring strain and temperature, is being installed during the construction of Principal Tower, a 50-storey reinforced concrete building in London. DFOS sensors are being embedded inside two columns and two walls as the construction progresses. Using the strain and temperature data acquired from this system, the axial deformation relative to the ground level can be calculated along the whole height of the completed elements, at any time during the construction. Thus, the engineers and contractors are able to verify their predictions and adjust their assumptions if necessary. A selection of the data acquired during the construction of the first 17 levels of the building is presented. These data have shown that the amount of shortening experienced by a member is influenced by the member’s stiffness and size. The monitoring data have also revealed that thermal movement has a significant effect on the overall axial displacement of the building