High-pressure Arc Lamp Research Articles

Asymmetrical Modes of Outdoor Lighting Lines

Asymmetrical modes of the outdoor lighting network can be caused by disconnecting of a part of the luminaires in order to electrical energy savings at night; also – by asymmetry of voltage in power points. The possible alternative symmetric modes of energy saving to replace the incomplete-phase operation of the line have been analyzed. Calculations of various symmetric and asymmetric modes of the lighting line were carried out without taking into account and taking into account high harmonics up to the 39th one. Calculations have been performed with the programs of MathCad software. As light sources, in the calculations the widely used luminaries with high-pressure sodium arc lamps connected through electromagnetic start-up equipment were considered. Such luminaries are sources of high harmonics, and they distort the sinusoidal voltage. The values of currents, power, power loss, voltage drop in all areas of the lighting line, the voltage at the terminals of the lamps for each phase (operating parameters) are determined. The diagrams of the voltage distribution at the points of the lighting line are plotted for the considered modes of operation. The annual electric power consumption of the lighting line has been calculated for different variants of operation, and the obtained results have been compared. When refusing to disconnection of part of the luminaires at night and using a smooth transition to a lower voltage (symmetrical) at a power point or using two-stage ballast devices, uneven illumination appears less when the level of electricity consumption is comparable. The presence of voltage asymmetry at the power point, as well as the disconnection of one phase, leads to an increase in currents, power losses and voltage. The current in the zero working conductor can exceed the currents in the phase conductors (when calculated taking into account the higher harmonics). Accounting for higher harmonics allows one to determine the operating parameters more accurately, on the basis of which the electricity power consumption can be estimated.

The influence of the LED lighting on structural-functional parameters of lettuce plants

Comparative studies were conducted on morphofunctional parameters of lettuce (Lactuca sativa) plants cultivated with the use of supplementary lighting from different light sources – LED lamps, high-pressure mercury arc lamp (HPM) and high-pressure sodium arc lamp (HPS). The work showed that morphofunctional parameters of lettuce were significantly higher with LED lighting, in comparison to plants cultivated with HPM illumination, and main parameters of leaves grown under LED were barely discernible from the samples grown under HPS lighting. We observed accelerated transfer into reproductive period during HPM lighting, what can lead to quality degradation of the product. Considering the approximate values of leaf character range in experiments with HPS and LED lighting and greater energy efficiency of LED, light emitting diodes are obviously more promising for supplementary illumination in protected ground conditions.

The influence of different lighting sources on growth and development of tomato plants

Comparative study was conducted on morphofunctional parameters of tomato plants (Solanum lycopersicum L.) under diverse supplementary lighting conditions – electrodeless lamps (EL), high-pressure mercury arc lamps (HPM) and high-pressure sodium arc lamps (HPS). The work showed, that plants, cultivated under 5,000 lux EL lighting, had higher morphometric parameters, their leaves contained more chlorophyll, and they were outgrown, in comparison to plants, growth in HPS and HPM lighting conditions. These results demonstrate the profitableness of EL light flux, which contains constant PAR spectrum, for tomato plants growth and development.

Measurement of the Spectral Response of Spiral-Antenna Coupled Superconducting Hot Electron Bolometers

Measured spectral response of spiral-antenna coupled superconducting hot electron bolometers (HEBs) often drops dramatically at frequencies that are still within the frequency range of interest (e.g., ~ 5 THz). This is inconsistent with the implied low receiver noise temperatures from the same measurements. To understand this discrepancy, we exhaustively test and calibrate the thermal sources used in Fourier transform spectrometer measurements. We first investigate the absolute emission spectrum of high-pressure Hg arc lamp, then measure the spectral response of two spiral-antenna coupled NbN HEBs with a Martin-Puplett interferometer as spectrometer and 77 K blackbody as broadband signal source. The measured absolute emission spectrum of Hg arc lamp is proportional to frequency, corresponding to an equivalent blackbody temperature of 4000 K at 1 THz, 1500 K at 3 THz, and 800 K at 5 THz, respectively. Measured spectral response of spiral-antenna coupled NbN HEBs, corrected for air absorption, is nearly flat in the frequency range of 0.5-4 THz, consistent with simulated coupling efficiency between HEB and spiral-antenna. These results explain the discrepancy, and prove that spiral-antenna coupled superconducting NbN HEBs work well in a wide frequency range. In addition, this calibration method and these results are broadly applicable to other quasi-optical THz receivers.

Introducing the Effect of Chinese Chlorella as a Photosensitizing Drug at Different Temperatures

Chinese Chlorella is natural algae seafood is widely used as a food substitute. Treatment of localized cancer cells by natural photosensitizer drugs extracted from herbs received intensive improvements with very high demands. Fractional hemolysis of the red blood cells incorporated with Chinese Chlorella in vitro has been reported. Continuous and delayed photohemolysis at different concentrations and different irradiation times were investigated. The samples irradiated with high-pressure arc lamp of intensities 58.07 J/cm2 ± 1.45 and 64.21 J/cm2 ± 1.98. The power dependent parameters of the relationship between time required to rupture 50% of the cells (t50) with different concentration and different irradiation time are found to be 0.63 ± 0.06 and 3.38 ± 0.17 respectively. These results suggested that, Chinese Chlorella could be one of the natural potential drugs in photodynamic therapy.

Preparation, Characterization of N-Ti-MCM-22 Molecular Sieve and its Photocatalytic Properties

Nanocrystalline N-doped and Ti-containing MCM-22 catalyst was synthesized by the static hydrothermal method, using sodium azide as nitrogen source for doping, and tetra-n-butyl titanate [Ti(OC4H9)4] as precursors of TiO2. The catalysts were characterized by X-ray diffraction, transmission electron microscopy, and energy-dispersive spectroscopy.During liquid phase photocatalytic degradation of methylene blue (MB) under high-pressure Hg arc lamp irradiation, the asprepared N-doped Ti-MCM-22 exhibited much higher activity than the undoped Ti-MCM-22, attributed to the effect of nitrogen dopant.

Photocatalysis of sulfo and carboxy derivatives of indigo in a TiO2 slurry with the use of polychromatic irradiation

The photocatalytic decomposition of indigo-5,5′-disulfonic acid (indigocarmine) and indigo-6,6′-dicarboxylic acid has been studied using TiO2 suspension and the polychromatic irradiation of a high-pressure Hg arc lamp. The dyestuffs were dissolved in aqueous medium at pH = 10 and photolyzed in a back-flow tubular photoreactor. The reaction products were determined by HPLC, NMR and MS spectroscopy. Two main photoproducts obtained from indigocarmine (2-amino-5-sulfobenzoic acid and isatine-5-sulfonic acid) were detected. The photocatalysis of indigo-6,6′-dicarboxylic acid gave aminoterephthalic acid and isatine-6-carboxylic acid as two main products. The quantitative analyses of reaction products were performed with UV/Vis and HPLC using chemical standards. A stoichiometric model and kinetic description of photocatalysis of sulfo and carboxy indigo dyes are suggested. The effect of hydroxide and carbonate anions on the rate of photocatalysis was also studied.

Preparation and characterization of N–Ti-MCM-22 mesoporous molecular sieve and investigation of its photocatalytic properties

Nanocrystalline N-doped and Ti-containing MCM-22 catalyst was synthesized by the static hydrothermal method, using sodium azide as nitrogen source for doping, and tetra-n-butyl titanate [Ti(OC4H9)4] as precursor for TiO2. The catalysts were characterized by X-ray diffraction, transmission electron microscopy, and energy-dispersive spectroscopy. The results showed that a mesoporous region with ca. 3-nm pore size was created by expansion between lamellar crystalline sheets in Ti-MCM-22. Nitrogen was substituted for some of the lattice oxygen atoms. During liquid phase photocatalytic degradation of methylene blue under high-pressure Hg arc lamp irradiation, the as-prepared N-doped Ti-MCM-22 exhibited much higher activity than the undoped Ti-MCM-22, attributed to the effect of the nitrogen dopant. The effects of N-doping amount, catalyst concentration, initial solution pH, and initial concentration of MB on the photocatalytic activity were investigated.

Photochemistry of coronene with water at 10 K: first tentative identification by infrared spectroscopy of oxygen containing coronene products

UV photochemistry of a polycyclic aromatic hydrocarbon model, coronene (C(24)H(12)), has been investigated when it is in interaction with water in argon cryogenic matrices, adsorbed on amorphous water ice films, and embedded in solid water. Photoprocessing, carried out at 10 K and λ > 235 nm by means of a high-pressure Hg arc lamp, results in the oxidation and reduction of coronene. These species have been tentatively identified as being the 1,10-dihydroxycoronene and the 1,10-coroquinone by FTIR spectroscopy with the support of isotopic experiments and DFT calculations. These photochemical products most likely form, after hydrogen bonding between C(24)H(12) and H(2)O, through ionization of the PAH and subsequent reactivity with water upon irradiation. Cations, thus generated, react subsequently with water yielding the production of oxygen containing coronene compounds. Such species are of particular interest as they may form in interstellar and early Solar System ices, and are also of astrobiological significance as they could play an important role in processes taking place in most of the living organisms.

A Dynamic Model of a High-Temperature Arc Lamp

High-temperature high-pressure arc lamps are used to thermally process semiconductor wafers. An accurate dynamic model that links the radiation output to the current input would facilitate the design of a power circuit that optimizes energy transfer to the arc. In this paper, a dynamic arc model is derived using averaging of the energy balance equation over spatial domains. This space averaging approach (the “finite-volume method”) accurately models the energy balance equation, as tested with both steady and transient arc currents, including high-energy pulses with a current amplitude range from 400 A to 27 kA and a pulsewidth of a millisecond or less.

Development of a Selective Light-Emitting Diode Photolytic NO2 Converter for Continuously Measuring NO2 in the Atmosphere

A photolytic converter of nitrogen dioxide (NO(2)) to nitric oxide (NO) using light-emitting diodes (LEDs) has been designed to measure NO(2) in the troposphere. The typical electrical power consumption of the photolytic converter (PLC) is only 44 W. The maximum conversion efficiency of NO(2) to NO of the photolytic converter is around 90%, which is higher than that of metal halides or high-pressure Xe arc lamps (up to ∼70%). The conversion efficiency of the PLC was almost constant for at least 2.5 months. The conversion efficiency of peroxyacetyl nitrate by the LED-PLC was measured to be 2.6 ± 0.1% (1σ). The interference of HONO using the PLC was experimentally estimated to be less than 3%, which is within the uncertainty of the instrument. An intercomparison of NO(2) measurements between the PLC-CLD and the laser-induced fluorescence (LIF) technique was conducted, and the NO(2) concentrations measured by the PLC-CLD method were in agreement with those obtained by the LIF technique, within the uncertainties of the instruments. Continuous observations were made on Fukue Island, a remote area. These results demonstrate the performance of the PLC for continuous ambient measurements.

High-resolution far-infrared spectroscopy at NSLS beamline U12IR

A Bruker model IFS 125HR Fourier transform interferometer has been installed and its performance tested using high-brightness, far-infrared synchrotron radiation. Results of absorption measurements for the rotational modes of water vapor demonstrate a nearly 10-fold improvement in signal-to-noise when compared with the instrument’s internal high-pressure Hg arc lamp source.

Measuring solid-state quantum yields: The conversion of a frequency-doubled Nd:YAG diode laser pointer module into a viable light source

This article outlines the difficulties associated with measuring quantum yields for solid-state samples using a high-pressure mercury arc lamp as the irradiation source. Details are given for the conversion of an inexpensive frequency-doubled neodymium-doped yttrium aluminum garnet (Nd:YAG) diode laser pointer module into a viable irradiation source. The modified Nd:YAG laser was incorporated into a computer-controlled system, which allowed for the simultaneous irradiation and spectroscopic monitoring of the sample. The data obtained with the Nd:YAG diode laser system show far less scatter than data obtained with a high-pressure Hg arc lamp, and consequently the degradation rates obtained with the laser system could be calculated with far greater accuracy.

X-ray absorption imaging of high-pressure lighting plasmas

X-ray absorption has been used to image the distribution of mercury (Hg) in high-pressure arc lamps used for lighting. Here, several images are presented showing the analytic transformation of raw X-ray data into an image of the Hg vapor density in a cylindrically symmetric arc.

Factors influencing the minimum arc sustaining electric field and associated current for a high-pressure-vortex-water-wall-arc lamp

Pulsed high pressure arc lamps are often operated with a small sustaining current during the interpulse period in order to minimize the arc expansion time, to increase the lamps' operating lifetime and to enable operation at higher repetition frequencies. It is common to select a sustaining current level associated with an arc voltage which lies between the maximum DC source voltage and the minimum sustaining voltage. This paper shows that the radius of the arc tube, the amount of convection and radiation and the assumptions regarding the nature of the radiation model strongly influence the current value associated with the minimum sustaining voltage. Pressure and boundary temperature have only a slight effect on the current associated with the minimum sustaining voltage but affect the minimum sustaining voltage. Heat conduction plays the primary role in tubes with a small radius while optically thin radiation plays the primary role in tubes with a large radius. The simulation results were obtained using Patankar's control volume algorithm along with boundary conditions. The extended Ellenbass-Heller equation in cylindrical coordinates was solved. The numerical results for the electric field as a function of current are somewhat smaller than the experimentally derived results. Convection appears to be the reason for this difference.

41.2: Lifetime and Wattage Extension of High‐Pressure Hg Arc Lamps with Enhanced Reflector Modules

AbstractThe eele‐enhanced™ lamp reflector module geometry enables, besides higher collection efficiency for smaller collection étendue values, also increased cooling design freedoms. Experimental results prove that with the correct cooling design both lifetime and light output decay is significantly improved for both large and small collection étendue values when a standard Osram P‐VIP™ burner (120W, 1.3mm arc gap) is operated in either a normal‐, under‐ or over‐powered (80–150W) mode inside a 45mm tall, electroformed, eele‐enhanced™ lamp reflector module.

The role of the triplet state on the photobleaching processes of xanthene dyes in a poly(vinyl alcohol) matrix

This work presents the results for the temperature dependence of the photobleaching reactions of Fluorescein and Rose Bengal dissolved in poly(vinyl alcohol) in the presence of diethylenetriamine, potassium dichromate and 2-aminoethanethiol hydrochloride. These samples were subjected to a continuous irradiation with a 150 W mercury high pressure arc lamp at a wavelength coincident with the maximum of the dye absorption. The photobleaching processes were described by a double exponential and a mono-exponential function for Fluorescein and Rose Bengal, respectively. Apparent activation energies were calculated using the Arrhenius plots and these values were strongly affected by the presence of additives. Different additives are employed in the studies of the photobleaching reactions of Fluorescein and Rose Bengal in poly(vinyl alcohol) matrices: (a) diethylenetriamine is a quencher of all excited states; (b) potassium dichromate is an electron acceptor complexed with the polymer chains and inhibited the photobleaching; (c) 2-aminoethanethiol hydrochloride is an efficient quencher of the triplet state. The role of these additives upon the photoreaction is discussed.

Measurement of the Hg distribution in a high-pressure arc lamp by x-ray absorption

We have used an x-ray absorption technique to measure the distribution of Hg atoms in a pure-Hg high-pressure arc lamp. The x rays are obtained from a molybdenum-anode x-ray tube at an accelerating potential of 25.3 kV. The spectral distribution of x rays which produce the absorption signal consists mainly of the Mo Kα and Kβ fluorescence peaks at 17.5 and 19.6 keV, respectively. Plane-wave illumination of the lamp and two-dimensional detection of the transmitted x rays allow us to probe the Hg atom density in all regions of the lamp, simultaneously, with a spatial resolution of 170 μm. A complete two-dimensional map of the density is obtained by Abel inversion of the absorption data. This map extends all the way out to the arc-envelope boundary and includes the cold regions of the discharge behind the electrodes. A temperature map of the discharge is obtained by combining the density information with an optical emission measurement of the core temperature at a single axial location.

Dye-polymer interactions controlling the kinetics of fluorescein photobleaching reactions in poly(vinyl alcohol)

This work presents results for the temperature dependence of the photobleaching reactions of Fluorescein dissolved in poly (vinyl alcohol) (PVA) irradiated by a continuous 150 W Hg high pressure arc lamp. We observed that the photobleaching process efficiency is dependent on: lamp power, dye concentration and temperature. Although the photobleaching processes can only be described by a single-exponential function for lower concentration samples, a biphasic model must be employed for intermediate concentrations, resulting in one slower and one faster processes, while, for higher concentration samples, even multiple-exponential functions are unable to tit the experimental data. This complex behavior is probably due to the co-existence of many different types of energy transfer and photochemical processes with different rate constants. Therefore, a model based on a sequential distribution of site occupation by the dye molecules in the matrix, controlled by dyepolymer interaction strengths, is proposed to explain the complex-exponential kinetic behavior. Moreover, photobleaching process efficiency- is somewhat increased by temperature and, above the PVA glass transition temperature, T g, (350 K), it follows a first order kinetics, fitted by a mono-exponential function.

Power supply design considerations for maintaining a minimum sustaining current in a vortex water wall high-pressure argon arc lamp

Vortex water wall high-pressure argon arc lamps are used to generate intense light and are capable of operating at radiative efficiencies greater than 50%. These lamps are being considered for use in a pulsed DC mode of operation in the next generation of rapid thermal processing applications. The results of a series of experiments have shown that the breakdown to arc transition consists of a prethermionic electrode emission phase and a prethermal ionization phase. The large dynamic voltage and current range between the breakdown phase and the arc phase necessitates the use of three different power circuit topologies. A high-voltage ignition circuit is connected in series with an arc-sustaining power source. The series connection ensures that the arc-sustaining power supply is isolated from the high-voltage ignition circuit. The arc-sustaining current source power source consists of a step-down hysteresis-current-controlled DC/DC converter cascaded with a constant off-time output-voltage-controlled step-up DC/DC converter. The current-controlled converter supplies the minimum arc-sustaining current, whereas the step-up converter provides the minimum post-ignition prethermal ionization voltage. The inclusion of a shorting switch allows one to reduce the current ratings of the high-voltage circuit components. Finally, experimental verification of a simplified circuit model of the ignition to arc transition, the circuit operation, a power supply design procedure, and a design example are provided.