The International Symposia on the Science & Technology of Lighting (LS:X), founded in 1975, provide contemporaneous overviews of advances and frontier topics in lighting including: solid-state and legacy light source science and technology in the UV, visible and NIR regions; materials; control systems

The Sulfur Iodine cycle has great potential for large scale hydrogen production from water. The HI?, processing stage (Section III) of the cycle exhibits the major challenges. Among them, experimental vapour liquid equilibrium data is scarce, mainly due to inherent hurdles to monitor the system under operating conditions of this section, i.e. temperature, acidity, and corrosion. Until now, UV-Visible and FTIR spectroscopies are the online monitoring techniques of choice, however due their selection rules, there is no experimental spectroscopic evidence of H-2 during direct decomposition of HI. Bearing this in mind, here we demonstrate the feasibility of exploiting two different Raman spectroscopic techniques as in situ monitoring tools, to gain substantial knowledge on the mechanisms of hydrogen production in Section III. Whereas resonance Raman spectra revealed the occurrence of HI center dot(H2O)(3) in the vapour phase; coherent anti-Stokes Raman spectra of H2 allowed us to estimate kinetic data such as the activation energy for HI decomposition of a given hyper-azeotropic ternary mixture (i.e. x(HI): 0.144; x(I2:)0.308; x(H2O):0.548) is 149.15 kJ/mol. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

The present paper investigates the ionic species coexisting in the HI x feed of the sulfur‐iodine thermochemical cycle. For this purpose, Raman and inelastic neutron scattering as well as molecular modelling were applied to the study of the binary HI‐H2O system and the ternary HI‐I2‐H2O and KI‐I2‐H2O systems. Raman spectra, obtained at 298 K, strongly suggest the coexistence of , I−(I2), and I−(I2)2 species. Whereas on the other hand, inelastic neutron scattering spectra (20 K) revealed, for the first time, evidence for the presence of discrete water structural motifs under specific conditions. Molecular modelling of two idealized structures has allowed us to establish a reasonable interpretation of the important structural motifs in these systems, in terms of the azeotrope of the HI‐H2O system and the pseudoazeotrope of the HI‐I2‐H2O system.

The main parameters for precipitation of mixed carbonate materials have been studied by Raman microscopy. These carbonates are compounds of barium, strontium and calcium. It has been shown that the Raman spectrum of a sample is exclusively controlled by its composition, the precipitation parameters do not affect the crystal structure. Even at relatively low levels, the calcium content of a sample can dominate the vibrational frequencies as measured by Raman spectroscopy. Calcium contents greater than 17% show this effect to a considerable degree, and give the broadest or two Raman peaks and thus the least uniform unit cells. The analysis of the lattice modes demonstrates that each Raman shift observed for a mixed carbonate sample corresponds to a specific crystal structure. Some peaks lie within two or three shifts that are observed for different crystal structures.

The species present in the condensed phase of the HIx, hydrogen producing, feed in the water-splitting, sulfur-iodine thermochemical cycle have been investigated using spontaneous Raman scattering. Measurements of I-2-containing species in the low Raman-shift region from 50 to 400 cm(-1) in samples of the two aqueous binary systems, I-2/H2O and HI/H2O, and the ternary system HI/I-2/H2O with and without the addition of H2SO4 have provided a consistent picture of the aqueous iodine and polyiodide chemistry. Samples were contained in sealed silica ampoules and were heated to temperatures in the range 20-300 degrees C. The results, which cover a wide range of I-2 and HI mole fractions, and x(I2)/x(HI) mole ratios, in the HI/I-2/H2O system, reveal the co-occurrence of H+I3-, H+-I (I-2), and H+-I (I-2)(2) solvated species in the condensed phase of HIx. Thus, while the first is mostly evident by its strong fundamental band with Raman shift in the range from 110 to 115 cm(-1), the other two species appear convoluted in a broad prominent band whose Raman shift ranges between 153 and 172 cm(-1) depending on the x(I2)/x(HI) mole ratio. These well characterized Raman features are proposed as an in situ diagnostic for process control of the cycle. Copyright (C) 2010 John Wiley & Sons, Ltd.

The tin(II) halides are important in a number of industrial processes and technological devices, for example, in the chemical vapor deposition of tin(IV) oxide films for the semiconductor industry, in the production of catalysts, and as a method of refining the spectral output of high intensity discharge lamps. Modeling of such processes requires databases of reliable, self-consistent thermochemical parameters. A survey of the physicochemical properties and appropriate standard thermochemical data has been made for the tin(II) halides, SnXX' (X, X' = Cl, Br, I), and a self-consistent set of thermochemical parameters are selected for the solid, liquid, and gas phases of these materials. In a few cases where data are simply unavailable, data are derived using a variety of estimation techniques. The benchmark employed to select the parameters in this work is that they accurately predict experimental vapor pressures where these are available. Finally, estimation techniques (Supporting Information) are used to provide supporting evidence as to the correctness of the magnitudes of data selected using the benchmark.

A spectroscopic method to determine dopant concentrations in silicas used in silica on silicon planar waveguides has been developed. Raman spectroscopic measurements in the range 740 cm−1–1370 cm−1 of cross-sections of the glass layers identified correlations between simple, rapidly calculated, spectral features related separately to each of the three dopants, boron, phosphorous and germanium, and the wt% analyses results for these dopants from inductively coupled plasma mass spectrometry (ICP-MS) measurements on fragments from the respective wafers. The calibration wafers comprised a set of monitor wafers with dopant concentrations spanning the ranges used in devices. The Raman-based analyses were able to determine boron and phosphorous wt% s in boro-phosphosilicate cladding glasses with accuracies of ≈0.1 wt% and germanium wt% s in core glasses with an accuracy of at least ≈0.3 wt% (small batch size). The method, which performed successfully in blind tests, provides a spatially resolving and rapid alternative to ICP-MS analyses of monitor wafers. Exploratory face-on measurements were performed on device wafers. Spectra of the cladding, core and underlayer were obtained from AWG samples. The effects of the confocal volume’s finite size and refractive index differences were observed. Exploratory measurements using UV Raman excitation showed potential advantages for cladding glass analyses.

Solid state lighting (SSL) systems are set to begin competing with a number of mature lighting technologies in mainstream markets for narrow- and wide-area illumination. The paper provides a summary overview of the present state of the established illumination lighting sector in terms of its scale and global energy usage, and its core technologies and their major performance characteristics. The established technologies are themselves still evolving in response generally to growing, world-wide, legislative and environmental pressures, and also, no doubt, to the stimulus provided by the rapid advances in the performance of white-LED modules. Several promising new thermal and discharge lamp technologies are identified and discussed briefly.

The objective of HYTHEC—HYdrogen THErmo-chemical Cycles—is to investigate the effective potential for massive hydrogen production of the S–I thermo-chemical cycle, and to compare it with the hybrid S Westinghouse (WH) cycle. The project aims to conduct flow-sheeting, industrial scale-up, safety and costs modelling, to improve the fundamental knowledge and efficiency of the S–I cycle H2 production step, and to investigate a solar primary energy source for the H2SO4 decomposition step which is common to both the cycles. Initial reference flow-sheets have been prepared and compared. First data and results are available now on the coupling of S–I cycle with a very high temperature nuclear reactor, scale-up to industrial level and cost estimation, improvement of the knowledge of the HIx mixture (S–I cycle) and membrane separation, splitting of sulphuric acid using a solar furnace, and plant concepts regarding the WH process.

Polypyrrole (PPy) has been deposited from aqueous solution onto submicrometer-sized sulfur-rich poly[bis(4-vinylthiophenyl)sulfide] (PMPV) latex particles. The PMPV seed particles and resulting composite particles were extensively characterized using scanning electron microscopy, X-ray photoelectron spectroscopy, FT-IR spectroscopy, helium pycnometry, Raman spectroscopy, and electrical conductivity measurements. Four-point probe measurements on pressed pellets indicate conductivities of around 6 x 10(-5) S cm(-1) for a polypyrrole loading of approximately 11.5%. This suggests a somewhat patchy, nonuniform polypyrrole overlayer, which is consistent with our Raman spectroscopy studies. Despite their relatively low conductivities, these polypyrrole-coated PMPV latexes can be accelerated up to hypervelocities (> 20 km s(-1)) using a high voltage (2 MV) van de Graaf instrument. In view of their high sulfur contents (ca. 28%), these new electrically conductive latexes are expected to be interesting synthetic mimics for understanding the behavior of sulfur-based micrometeorites, whose existence has been postulated by planetary scientists investigating signs of volcanic activity on one of Jupiter's moons (Io).

A Spice-compatible dynamic conductance model of a fluorescent lamp for use in electronic ballast simulation is presented. The time-dependent conductance of the fluorescent lamp is derived from a plasma ionization balance equation that uses simplified descriptions of the physical processes within the lamp as its basis. The model has been designed to enable user-defined lamp radius, length, buffer gas pressure and cold-spot temperature as input parameters thus representing a valuable tool for ballast simulations. Simulation results are compared to experimental measurements and satisfactory agreement is achieved.

The coherent anti-stokes Raman spectroscopy (CARS) technique was used for the first time to determine vibrational spectra of high temperature niobium pentachloride (NbCl5). Vapour phase CARS spectra of NbCl5 were obtained from the sample at temperatures 578K, 623K and 673K for υ1 mode and 573K for υ2 mode, respectively. The vibrational frequencies measured were 394cm−1 for υ1 mode and 312cm−1 for υ2 mode, respectively.

The Lattice Boltzmann Method (LBM) which is derivative of the lattice gas automata (LGA) has recently studied as a numerical scheme for simulating fluid flows governed by the Navier-Stokes equation. The LBM is a discrete numerical method based on the Boltzmann equation. The dynamics of the LBM is divided into a propagation step and a collision step. We have proposed a model for weakly ionized plasma by introducing diffusion as a velocity to LBM. In our LBM model, ionization, recombination at the wall and ambipolar diffusion are considered. This model uses 2D9V (2 dimensions, 9 velocities) model and BGK collision operator. We have simulated various shape of discharge tubes by this model. MATLAB is suitable for matrix calculation and has a command for shifting matrix which is important in LBM. By this work, it is shown that our model simulates weakly ionized plasma well.

In this paper, we demonstrate the possibilities that exist in developing a high brightness white light source. The lamp employs mercury at a few Torr and is operated with short pulses of the order of 1 mu s at a frequency of 10 kHz. The emission spectrum is atomic in nature and the white light is the outcome of a relative enhancement of the mercury yellow lines at 577 and 579 nm with respect to the rest of the visible lines, which shifts the colour coordinates of the source towards the black body locus of the chromaticity diagram. The pulse operation of a lamp containing mercury at a vapour pressure of 20 Torr offers a greater near-UV and visible output compared to a phosphor-uncoated, low-pressure pulsed compact mercury discharge.