Behavioral and physiological photoresponses to light intensity by intertidal microphytobenthos

Science.gov (United States)

Du, Guoying; Yan, Hongmei; Liu, Chunrong; Mao, Yunxiang

2017-03-01

Behavioral and physiological responses to light are the two major mechanisms by which natural microphytobenthic assemblages adapt to the intertidal environment and protect themselves from light stress. The present study investigated these photoresponses with different light intensities over 8 h of illumination, and used a specific inhibitor (Latrunculin A, Lat A) for migration to compare migratory and non-migratory microphytobenthos (MPB). Photosynthetic activity was detected using rapid light curves and induction curves by chlorophyll fluorescence. It showed distinct variation in migratory responses to different light intensities; high light induced downward migration to avoid photoinhibition, and low and medium light (50-250 μmol/(m2·s)) promoted upward migration followed by downward migration after certain period of light exposure. No significant difference in non-photochemical quenching (NPQ) or PSII maximal quantum yield (Fv/Fm) was detected between low and medium light irradiance, possibly indicating that only high light influences the photosynthetic capability of MPB. Decreased photosynthetic activity, indicated by three parameters, the maximum relative electron transport rate (rETRmax), minimum saturating irradiance (E k) and light utilization coefficient (α), was observed in MPB after exposure to prolonged illumination under low and medium light. Lat A effectively inhibited the migration of MPB in all light treatments and induced lower Fv/Fmunder high light (500 and 100 μmol/(m2·s)) and prolonged illumination at 250 μmol/(m2·s), but did not significantly influence Fv/Fmunder low light (0-100 μmol/(m2·s)) or NPQ. The increase of NPQ in Lat A treatments with time implied that the MPB assemblages can recover their physiological photoprotection capacity to adapt to light stress. Non-migratory MPB exhibited lower light use efficiency (lower α) and lower maximum photosynthetic capacity (lower rETRmax) than migratory MPB under light intensities above

LED intense headband light source for fingerprint analysis

Science.gov (United States)

Villa-Aleman, Eliel

2005-03-08

A portable, lightweight and high-intensity light source for detecting and analyzing fingerprints during field investigation. On-site field analysis requires long hours of mobile analysis. In one embodiment, the present invention comprises a plurality of light emitting diodes; a power source; and a personal attachment means; wherein the light emitting diodes are powered by the power source, and wherein the power source and the light emitting diodes are attached to the personal attachment means to produce a personal light source for on-site analysis of latent fingerprints. The present invention is available for other applications as well.

Effect of high wavelengths low intensity light during dark period on physical exercise performance, biochemical and haematological parameters of swimming rats.

Science.gov (United States)

Beck, W; Gobatto, C

2016-03-01

Nocturnal rodents should be assessed at an appropriate time of day, which leads to a challenge in identifying an adequate environmental light which allows animal visualisation without perturbing physiological homeostasis. Thus, we analysed the influence of high wavelength and low intensity light during dark period on physical exercise and biochemical and haematological parameters of nocturnal rats. We submitted 80 animals to an exhaustive exercise at individualised intensity under two different illuminations during dark period. Red light (> 600 nm; sports performance experiments.

Light intensity dependent Debye screening length in undoped photorefractive titanosillenite crystals

OpenAIRE

de Oliveira, I; Frejlich, J

2012-01-01

We report on the experimental evidence of the light intensity dependence of the Debye screening length l(s) in undoped photorefractive titanosillenite crystals (Bi12TiO20) by measuring the holographic gain and diffraction efficiency in a two-wave mixing experiment under 532 nm wavelength laser light. Debye length shows saturation at high values of the light intensity. Results are in agreement with the theoretical development. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/...

Light intensity dependent optical rotation in azobenzene polymers

Science.gov (United States)

Ivanov, M.; Ilieva, D.; Petrova, T.; Dragostinova, V.; Todorov, T.; Nikolova, L.

2006-05-01

We investigate the self-induced rotation of the azimuth of light polarization ellipse in azobenzene polymers. It is initiated by the photoreorientation and ordering of the azobenzenes on illumination with elliptically polarized light resulting in the appearance of an optical axis whose direction is gradually rotated along the depth of the film. A macroscopic chiral structure is created with a pitch depending on light ellipticity and the photobirefringence ▵n in the successive layers of the film. In this work we make use of the fact that at elevated temperatures ▵n is very sensitive to light intensity. In our acrylic amorphous azobenzene polymer at temperatures 50-65°C the saturated values of ▵n are much higher for low intensity of the exciting light than for higher intensity. In this temperature range the polarization azimuth of monochromatic blue light with different intensity is rotated to a different angle after passing through the polymer film. This effect can be used for passive elements rotating the polarization azimuth depending on light intensity and for the formation of light beams with a space-variant polarization state.

effect of light curing unit characteristics on light intensity output

African Journals Online (AJOL)

2013-09-09

Sep 9, 2013 ... in Nairobi and their effect on light intensity output, depth of cure (DOC) and ... result in gradual reduction in the energy output of ..... of LED lights are compared with QTH lights could ... influence on the SMH of dark shades.

Gas sensing properties of indium–gallium–zinc–oxide gas sensors in different light intensity

Directory of Open Access Journals (Sweden)

Kuen-Lin Chen

2015-06-01

Full Text Available We have successfully observed the change in indium–gallium–zinc–oxide (IGZO gas sensor sensitivity by controlling the light emitting diode (LED power under the same gas concentrations. The light intensity dependence of sensor properties is discussed. Different LED intensities obviously affected the gas sensor sensitivity, which decays with increasing LED intensity. High LED intensity decreases not only gas sensor sensitivity but also the response time (T90, response time constant (τres and the absorption rate per second. Low intensity irradiated to sensor causes high sensitivity, but it needs larger response time. Similar results were also observed in other kinds of materials such as TiO2. According to the results, the sensing properties of gas sensors can be modulated by controlling the light intensity.

Intense beams of light ions

International Nuclear Information System (INIS)

Camarcat, Noel

1985-01-01

Results of experiments performed in order to accelerate intense beams of light and heavier ions are presented. The accelerating diodes are driven by existing pulsed power generators. Optimization of the generator structure is described in chapter I. Nuclear diagnostics of the accelerated light ion beams are presented in chapter II. Chapter III deals with the physics of intense charged particle beams. The models developed are applied to the calculation of the performances of the ion diodes described in the previous chapters. Chapter IV reports preliminary results on a multiply ionized carbon source driven by a 0.1 TW pulsed power generator. (author) [fr

Effects of different light intensities in the morning on dim light melatonin onset.

Science.gov (United States)

Kozaki, Tomoaki; Toda, Naohiro; Noguchi, Hiroki; Yasukouchi, Akira

2011-01-01

The present study evaluated the effects of exposure to light intensity in the morning on dim light melatonin onset (DLMO). The tested light intensities were 750 lux, 150 lux, 3000 lux, 6000 lux and 12,000 lux (horizontal illuminance at cornea), using commercial 5000 K fluorescent lamps. Eleven healthy males aged 21-31 participated in 2-day experiments for each light condition. On the first experimental day (day 1), subjects were exposed to dim light (dim light (light conditions for 3 h in the morning. The experimental schedule after light exposure was the same as on day 1. On comparing day 2 with day 1, significant phase advances of DLMO were obtained at 3000 lux, 6000 lux and 12,000 lux. These findings indicate that exposure to a necessary intensity from an ordinary light source, such as a fluorescent lamp, in the morning within one day affects melatonin secretion.

Cost-benefit analysis of retrofit of high-intensity discharge factory lighting with energy-saving alternatives

Energy Technology Data Exchange (ETDEWEB)

Preston, D.J. [Alabama Industrial Assessment Center, The University of Alabama, 1530 W. Tremont St, Allentown, PA 18102 (United States); Woodbury, K.A. [Alabama Industrial Assessment Center, The University of Alabama, 290 Hardaway Hall, Box 870276, Tuscaloosa, AL 35487-0276 (United States)

2013-05-15

Due to increased concern about overall energy costs and the appearance of efficient and inexpensive lighting system alternatives, factories and plants with high-intensity discharge (HID) lighting are forced to consider retrofit with more modern, energy-efficient lighting. The decision is complicated from an economic perspective, and there is a lack of information readily available on the topic. This study provides an analysis of the replacement by retrofit of common probe-start metal halide and high-pressure sodium industrial lighting systems. Retrofit options considered include the more recent pulse-start metal halide lamps and a range of T5 high output and T8 fluorescent lamp configurations. Recent data on lighting system pricing, labor and energy costs, and time required for tasks are reported. The results generated include savings, payback period, and net present value for many retrofit options, as well as the change in energy consumption, carbon footprint, and lumen output for each retrofit. Effects of varying rate of return and daily duration of operation are considered. Based on change in lumen output, payback period, net present value, and comparison of lighting quality, one or two options are recommended from the overall retrofit options considered. A fluorescent retrofit is recommended for each of the HID initial scenarios considered. The payback period is no more than 3 years in any recommended case. The focus of this study is on the potential energy and cost savings, and some proposed solutions may, or may not, be acceptable due to lack of illuminance uniformity.

Effects of Light Intensity on Growth, Anti-Stress Ability and Immune Function in Yellow Feathered Broilers

Directory of Open Access Journals (Sweden)

YL Guo

Full Text Available ABSTRACT An experiment was conducted to investigate the effects of light intensity on growth, anti-stress ability, and immune function of yellow feathered broilers. A total of 480 one-day-old male Lingnan yellow feathered broilers were randomly allocated to 4 treatments based on light intensity (1, 5, 20 and 80 lx with 8 replicates of 15 chicks each. The experiment lasted for 63 days. Compared with those under high light intensity, broilers exposed to low light intensity had higher (p<0.05 total antioxidant capacity (T-AOC, glutathione peroxidase (GSH-Px, a-Naphthylacetate esterase (ANAE+, antibody titer, but lower (p<0.05 malonaldehyde (MDA levels and heterophil/lymphocyte ratio (H/L. There was a linear effect for T-AOC(p=0.002, GSH-Px(p≤0.047, MDA (p=0.003, H/L(p≤0.014, ANAE+ (p≤0.044, and antibody titer (p≤0.021 with T-AOC, GSH-Px, ANAE+, and antibody titer increased significantly as light intensity decreased, whereas MDA and H/L were decreased with the decrease in light intensity. These results suggested that broilers under low light intensity could have similar performance, better anti-stress ability, stronger immune function, and more efficient in energy usage as compared with those exposed to high light intensity environment.

Case Study on Justification: High Intensity Discharge Lamps. Annex II

International Nuclear Information System (INIS)

2016-01-01

High intensity discharge lamps produce bright white light of a high intensity in an energy efficient manner. These lamps are typically used in large numbers in public and professional settings such as shops, warehouses, hotels and offices. They are also used in outdoor applications to illuminate streets, buildings, statues, flags and gardens and further as architectural lighting. They also have applications associated with film projection in cinemas, manufacture of semiconductors, fluorescence endoscopy and microscopy, schlieren photography, hologram projection, ultraviolet curing, sky beamers and car headlights. Some types of high intensity discharge lamp, as well as certain other consumer products for lighting, contain radioactive substances for functional reasons. The radionuclides that are typically incorporated into high intensity discharge lamps are 85 Kr and 232 Th. Given the wide range of uses, specific decisions on justification may be required for different applications. A small number of safety assessments for high intensity discharge lamps have been carried out and published. No published decisions at the national level specifically addressing the justification of the use of high intensity discharge lamps have been identified

Abnormal environmental light exposure in the intensive care environment.

Science.gov (United States)

Fan, Emily P; Abbott, Sabra M; Reid, Kathryn J; Zee, Phyllis C; Maas, Matthew B

2017-08-01

We sought to characterize ambient light exposure in the intensive care unit (ICU) environment to identify patterns of light exposure relevant to circadian regulation. A light monitor was affixed to subjects' bed at eye level in a modern intensive care unit and continuously recorded illuminescence for at least 24h per subject. Blood was sampled hourly and measured for plasma melatonin. Subjects underwent hourly vital sign and bedside neurologic assessments. Care protocols and the ICU environment were not modified for the study. A total of 67,324 30-second epochs of light data were collected from 17 subjects. Light intensity peaked in the late morning, median 64.1 (interquartile range 19.7-138.7) lux. The 75th percentile of light intensity exceeded 100lx only between 9AM and noon, and never exceeded 150lx. There was no correlation between melatonin amplitude and daytime, nighttime or total light exposure (Spearman's correlation coefficients all 0.5). Patients' environmental light exposure in the intensive care unit is consistently low and follows a diurnal pattern. No effect of nighttime light exposure was observed on melatonin secretion. Inadequate daytime light exposure in the ICU may contribute to abnormal circadian rhythms. Copyright © 2017 Elsevier Inc. All rights reserved.

SiPM response to long and intense light pulses

Energy Technology Data Exchange (ETDEWEB)

Vinogradov, S., E-mail: Sergey.Vinogradov@liverpool.ac.uk [University of Liverpool and Cockcroft Institute, Sci-Tech Daresbury, Keckwick Lane, Warrington WA4 4AD (United Kingdom); P.N. Lebedev Physical Institute of the Russian Academy of Sciences, 119991 Leninskiy prospekt 53, Moscow (Russian Federation); Arodzero, A. [Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139 (United States); RadiaBeam Technologies Inc., 1717 Stewart St., Santa Monica, CA 90404 (United States); Lanza, R.C. [Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139 (United States); Welsch, C.P. [University of Liverpool and Cockcroft Institute, Sci-Tech Daresbury, Keckwick Lane, Warrington WA4 4AD (United Kingdom)

2015-07-01

Recently Silicon Photomultipliers (SiPMs) have become well recognized as the detector of choice for various applications which demand good photon number resolution and time resolution of short weak light pulses in the nanosecond time scale. In the case of longer and more intensive light pulses, SiPM performance gradually degrades due to dark noise, afterpulsing, and non-instant cell recovering. Nevertheless, SiPM benefits are expected to overbalance their drawbacks in applications such as X-ray cargo inspection using Scintillation-Cherenkov detectors and accelerator beam loss monitoring with Cherenkov fibres, where light pulses of a microsecond time scale have to be detected with good amplitude and timing resolution in a wide dynamic range of 10{sup 5}–10{sup 6}. This report is focused on transient characteristics of a SiPM response on a long rectangular light pulse with special attention to moderate and high light intensities above the linear dynamic range. An analytical model of the transient response and an initial consideration of experimental results in comparison with the model are presented.

Simultaneous effects of light intensity and phosphorus supply on the sterol content of phytoplankton.

Directory of Open Access Journals (Sweden)

Maike Piepho

Full Text Available Sterol profiles of microalgae and their change with environmental conditions are of great interest in ecological food web research and taxonomic studies alike. Here, we investigated effects of light intensity and phosphorus supply on the sterol content of phytoplankton and assessed potential interactive effects of these important environmental factors on the sterol composition of algae. We identified sterol contents of four common phytoplankton genera, Scenedesmus, Chlamydomonas, Cryptomonas and Cyclotella, and analysed the change in sterol content with varying light intensities in both a high-phosphorus and a low-phosphorus approach. Sterol contents increased significantly with increasing light in three out of four species. Phosphorus-limitation reversed the change of sterol content with light intensity, i.e., sterol content decreased with increasing light at low phosphorus supply. Generally sterol contents were lower in low-phosphorus cultures. In conclusion, both light and phosphorus conditions strongly affect the sterol composition of algae and hence should be considered in ecological and taxonomic studies investigating the biochemical composition of algae. Data suggest a possible sterol limitation of growth and reproduction of herbivorous crustacean zooplankton during summer when high light intensities and low phosphorus supply decrease sterol contents of algae.

Acclimation of Swedish and Italian ecotypes of Arabidopsis thaliana to light intensity.

Science.gov (United States)

Stewart, Jared J; Polutchko, Stephanie K; Adams, William W; Demmig-Adams, Barbara

2017-11-01

This study addressed whether ecotypes of Arabidopsis thaliana from Sweden and Italy exhibited differences in foliar acclimation to high versus low growth light intensity, and compared CO 2 uptake under growth conditions with light- and CO 2 -saturated intrinsic photosynthetic capacity and leaf morphological and vascular features. Differential responses between ecotypes occurred mainly at the scale of leaf architecture, with thicker leaves with higher intrinsic photosynthetic capacities and chlorophyll contents per leaf area, but no difference in photosynthetic capacity on a chlorophyll basis, in high light-grown leaves of the Swedish versus the Italian ecotype. Greater intrinsic photosynthetic capacity per leaf area in the Swedish ecotype was accompanied by a greater capacity of vascular infrastructure for sugar and water transport, but this was not associated with greater CO 2 uptake rates under growth conditions. The Swedish ecotype with its thick leaves is thus constructed for high intrinsic photosynthetic and vascular flux capacity even under growth chamber conditions that may not permit full utilization of this potential. Conversely, the Swedish ecotype was less tolerant of low growth light intensity than the Italian ecotype, with smaller rosette areas and lesser aboveground biomass accumulation in low light-grown plants. Foliar vein density and stomatal density were both enhanced by high growth light intensity with no significant difference between ecotypes, and the ratio of water to sugar conduits was also similar between the two ecotypes during light acclimation. These findings add to the understanding of the foliar vasculature's role in plant photosynthetic acclimation and adaptation.

Effect of the light spectrum of various substrates for inkjet printed conductive structures sintered with intense pulsed light

International Nuclear Information System (INIS)

Weise, Dana; Mitra, Kalyan Yoti; Ueberfuhr, Peter; Baumann, Reinhard R.

2015-01-01

In this work, the novel method of intense pulsed light (IPL) sintering of a nanoparticle silver ink is presented. Various patterns are printed with the Inkjet technology on two flexible foils with different light spectra. One is a clear Polyethylenterephthalat [PET] foil and the second is a light brownish Polyimide [PI] foil. The samples are flashed with different parameters regarding to pulse intensity and pulse length. Microscopic images are indicating the impact of the flashing parameters and the different light spectra of the substrates on the sintered structures. Sheet and line resistance are measured and the conductivity is calculated. A high influence of the property of the substrate with respect to light absorption and thermal conductivity on the functionality of printed conductive structures could be presented. With this new method of IPL sintering, highly conductive inkjet printed silver patterns could be manufactured within milliseconds on flexible polymeric foils without damaging the substrate

Dynamics of triacylglycerol and EPA production in Phaeodactylum tricornutum under nitrogen starvation at different light intensities.

Directory of Open Access Journals (Sweden)

Ilse M Remmers

Full Text Available Lipid production in microalgae is highly dependent on the applied light intensity. However, for the EPA producing model-diatom Phaeodactylum tricornutum, clear consensus on the impact of incident light intensity on lipid productivity is still lacking. This study quantifies the impact of different incident light intensities on the biomass, TAG and EPA yield on light in nitrogen starved batch cultures of P. tricornutum. The maximum biomass concentration and maximum TAG and EPA contents were found to be independent of the applied light intensity. The lipid yield on light was reduced at elevated light intensities (>100 μmol m-2 s-1. The highest TAG yield on light (112 mg TAG molph-1 was found at the lowest light intensity tested (60 μmol m-2 s-1, which is still relatively low to values reported in literature for other algae. Furthermore, mass balance analysis showed that the EPA fraction in TAG may originate from photosynthetic membrane lipids.

Responses of fen plant species to groundwater level and light intensity

NARCIS (Netherlands)

Kotowski, W; van Andel, J; van Diggelen, R; Hogendorf, J.

Characteristic species of sedge-moss fen communities occur in constantly wet, nutrient-poor sites with a high penetration of light through the vegetation canopy. We studied the effects of water table depth and differences in light intensity on the performance of fen species. Three fen species (Carex

Crystalline silicon cell performance at low light intensities

Energy Technology Data Exchange (ETDEWEB)

Reich, N.H.; van Sark, W.G.J.H.M.; Alsema, E.A.; Turkenburg, W.C. [Utrecht University, Faculty of Science, Copernicus Institute for Sustainable Development and Innovation, Department of Science, Techonology and Society, Heidelberglaan 2, 3584 CS Utrecht (Netherlands); Lof, R.W.; Schropp, R.E.I. [Utrecht University, Faculty of Science, Debye Institute for Nanomaterials Science, Nanophotonics - Physics of Device, Utrecht University, P.O. Box 80.000, 3508 TA Utrecht (Netherlands); Sinke, W.C. [Energy research Centre of the Netherlands (ECN), P.O. Box 1, 1755 ZG Petten (Netherlands)

2009-09-15

Measured and modelled JV characteristics of crystalline silicon cells below one sun intensity have been investigated. First, the JV characteristics were measured between 3 and 1000 W/m{sup 2} at 6 light levels for 41 industrially produced mono- and multi-crystalline cells from 8 manufacturers, and at 29 intensity levels for a single multi-crystalline silicon between 0.01 and 1000 W/m{sup 2}. Based on this experimental data, the accuracy of the following four modelling approaches was evaluated: (1) empirical fill factor expressions, (2) a purely empirical function, (3) the one-diode model and (4) the two-diode model. Results show that the fill factor expressions and the empirical function fail at low light intensities, but a new empirical equation that gives accurate fits could be derived. The accuracy of both diode models are very high. However, the accuracy depends considerably on the used diode model parameter sets. While comparing different methods to determine diode model parameter sets, the two-diode model is found to be preferred in principle: particularly its capability in accurately modelling V{sub OC} and efficiency with one and the same parameter set makes the two-diode model superior. The simulated energy yields of the 41 commercial cells as a function of irradiance intensity suggest unbiased shunt resistances larger than about 10 k{omega} cm{sup 2} may help to avoid low energy yields of cells used under predominantly low light intensities. Such cells with diode currents not larger than about 10{sup -9} A/cm{sup 2} are excellent candidates for Product Integrated PV (PIPV) appliances. (author)

Performance of Arrowroot (Marantha arundinacea) in various light intensities

Science.gov (United States)

Oktafani, M. B.; Supriyono; Budiastuti, MTh S.; Purnomo, D.

2018-03-01

Arrowroot (Marantha arundinacea) is one of the potential food crops to support food security programs. Light intensity is one of the important factors for plant growth. Arrowroot cultivation technology still need further development. Traditionally, arrowroot grows wild under canopy without intentisification of cultivating which have low productivity. The purpose of research was to investigate the suitable light intensity for arrowroot. The experiment was conducted at Jumantono as Experimental Field of Faculty of Agricultural, University of Sebelas Maret Surakarta located in Karanganyar, from March to September 2016. The experiment used a complete randomized block design (CRBD) of light intensity level there are 27400 lux (full sun light), 18900 lux (shaded 31%), 13500 lux (shaded 51%) and 7400 lux (shaded 72%). Each treatment was replicated six times so there were 24 experimental units. The results showed that arrowroot is a low light adaptive plant. Arrowroot under the light intensity 7400 lux (27% full light), the number of leaves and tillers is not significantly different than under full light, although the plant is higher. The highest tuber diameter and length were 1.91 and 25.06 cm, respectively, and tuber weight reached 607.5-651.67 g per plant.

Response to variable light intensity in photoacclimated algae and cyanobacteria exposed to atrazine

Energy Technology Data Exchange (ETDEWEB)

Deblois, Charles P.; Dufresne, Karine [Department of Biological Sciences-TOXEN, Ecotoxicology of Aquatic Microorganisms Laboratory, Universite du Quebec a Montreal, Succ. Centre-Ville, Montreal, Quebec (Canada); Juneau, Philippe, E-mail: juneau.philippe@uqam.ca [Department of Biological Sciences-TOXEN, Ecotoxicology of Aquatic Microorganisms Laboratory, Universite du Quebec a Montreal, Succ. Centre-Ville, Montreal, Quebec (Canada)

2013-01-15

Atrazine is frequently detected in freshwater ecosystems exposed to agricultural waste waters and runoffs worldwide and it can affect non-target organisms (mainly photoautotrophic) and modify community structure. Meanwhile, light environment is known to vary between aquatic ecosystems, but also before and during the exposure to atrazine and these variations may modify the sensitivity to atrazine of photoautotroph organisms. In this study, 10 species of phytoplankton (chlorophytes, baccilariophytes and cyanophytes) acclimated to low or high light intensities were exposed to atrazine and light of different intensities to compare their combined effect. Our data showed that chlorophytes and baccilariophytes were more resistant to atrazine compared to cyanophytes for all light conditions. Atrazine was found to inhibit {Phi}{sup Prime }{sub M}, {Psi}{sub 0}, P{sub M} and non-photochemical quenching for all species indicating an effect on electron transport, primary production and photoregulation processes. These data also indicate a higher sensitivity of {Psi}{sub 0} (average {Psi}{sub 0}-EC{sub 50} of 91 {+-} 11 nM or 19.6 {+-} 0.9 {mu}g L{sup -1}) compared to {Phi}{sup Prime }{sub M} (average {Phi}{sup Prime }{sub M}-EC{sub 50} of 217 {+-} 19 nM or 46.8 {+-} 4.1 {mu}g L{sup -1}) and suggest that photoregulation processes activated in presence of light decrease the effect of atrazine. We also showed that increasing light intensity decreased {Phi}{sup Prime }{sub M}-EC{sub 50} in both low (except baccilariophytes) and high light acclimated conditions. Despite this similarity, most species acclimated to high light were found to have higher or similar {Phi}{sup Prime }{sub M}-EC{sub 50} compared to low light acclimated cells and thus, were less sensitive to atrazine in low light and high light environments. We concluded that an increase in the plastoquinone pool induced by acclimation to high light decreased the sensitivity to atrazine in phytoplankton and we hypothesized

LIGHT INTENSITY INFLUENCE ON STRONTIUM TITANATE BASED PHOTO- ELECTROCHEMICAL CELLS

Directory of Open Access Journals (Sweden)

D. Hertkorn

2017-07-01

Full Text Available The influence of light intensity on photo-electrochemical cells (PECs consisting of an n-type strontium titanate (SrTiO₃ photoanode and nickel cathode in potassium hydroxide electrolyte is studied. The band levels of an electrolyte-metal-semiconductor-electrolyte system are presented and the effect of different light intensities on the energy levels is investigated. Photocurrent density, quantum efficiency, and open circuit potential measurements are performed on the processed PECs under different light intensities (375 nm. It is demonstrated that a threshold value of the light intensity has to be reached in order to obtain positive photo activity and that beyond this value the performance remains nearly constant.

Light intensity affects the uptake and metabolism of glycine by pakchoi (Brassica chinensis L.)

Science.gov (United States)

Ma, Qingxu; Cao, Xiaochuang; Wu, Lianghuan; Mi, Wenhai; Feng, Ying

2016-02-01

The uptake of glycine by pakchoi (Brassica chinensis L.), when supplied as single N-source or in a mixture of glycine and inorganic N, was studied at different light intensities under sterile conditions. At the optimal intensity (414 μmol m-2 s-1) for plant growth, glycine, nitrate, and ammonium contributed 29.4%, 39.5%, and 31.1% shoot N, respectively, and light intensity altered the preferential absorption of N sources. The lower 15N-nitrate in root but higher in shoot and the higher 15N-glycine in root but lower in shoot suggested that most 15N-nitrate uptake by root transported to shoot rapidly, with the shoot being important for nitrate assimilation, and the N contribution of glycine was limited by post-uptake metabolism. The amount of glycine that was taken up by the plant was likely limited by root uptake at low light intensities and by the metabolism of ammonium produced by glycine at high light intensities. These results indicate that pakchoi has the ability to uptake a large quantity of glycine, but that uptake is strongly regulated by light intensity, with metabolism in the root inhibiting its N contribution.

High Precision Stokes Polarimetry for Scattering Light using Wide Dynamic Range Intensity Detector

Directory of Open Access Journals (Sweden)

Shibata Shuhei

2015-01-01

Full Text Available This paper proposes a Stokes polarimetry for scattering light from a sample surface. To achieve a high accuracy measurement two approaches of an intensity detector and analysis algorism of a Stokes parameter were proposed. The dynamic range of this detector can achieve up to 1010 by combination of change of neutral-density (ND filters having different density and photon counting units. Stokes parameters can be measured by dual rotating of a retarder and an analyzer. The algorism of dual rotating polarimeter can be calibrated small linear diattenuation and linear retardance error of the retarder. This system can measured Stokes parameters from −20° to 70° of its scattering angle. It is possible to measure Stokes parameters of scattering of dust and scratch of optical device with high precision. This paper shows accuracy of this system, checking the polarization change of scattering angle and influence of beam size.

Light intensity modulation in phototherapy

Science.gov (United States)

Lukyanovich, P. A.; Zon, B. A.; Kunin, A. A.; Pankova, S. N.

2015-04-01

A hypothesis that blocking ATP synthesis is one of the main causes of the stimulating effect is considered based on analysis of the primary photostimulation mechanisms. The light radiation intensity modulation is substantiated and the estimates of such modulation parameters are made. An explanation is offered to the stimulation efficiency decrease phenomenon at the increase of the radiation dose during the therapy. The results of clinical research of the medical treatment in preventive dentistry are presented depending on the spectrum and parameters of the light flux modulation.

Early Birds by Light at Night: Effects of Light Color and Intensity on Daily Activity Patterns in Blue Tits.

Science.gov (United States)

de Jong, Maaike; Caro, Samuel P; Gienapp, Phillip; Spoelstra, Kamiel; Visser, Marcel E

2017-08-01

Artificial light at night disturbs the daily rhythms of many organisms. To what extent this disturbance depends on the intensity and spectral composition of light remain obscure. Here, we measured daily activity patterns of captive blue tits ( Cyanistes caeruleus) exposed to similar intensities of green, red, or white light at night. Birds advanced their onset of activity in the morning under all light colors but more under red and white light than under green light. Offset of activity was slightly delayed in all light colors. The total activity over a 24-h period did not change but birds moved a part of their daily activity into the night. Since the effect of red and white lights are comparable, we tested the influence of light intensity in a follow-up experiment, where we compared the activity of the birds under different intensities of green and white light only. While in the higher range of intensities, the effects of white and green light were comparable; at lower intensities, green light had a less disturbing effect as compared with white light on daily rhythms in blue tits. Our results show that the extent of this disturbance can be mitigated by modulating the spectral characteristics and intensity of outdoor lighting, which is now feasible through the use of LED lighting.

Light-Intensity Physical Activity and All-Cause Mortality.

Science.gov (United States)

Loprinzi, Paul D

2017-07-01

Research demonstrates that moderate-to-vigorous physical activity (MVPA) is associated with a reduced risk of all-cause mortality. Few studies have examined the effects of light-intensity physical activity on mortality. Therefore, the purpose of this study was to examine the association between objectively measured light-intensity physical activity and all-cause mortality risk. Longitudinal. National Health and Nutrition Examination Survey 2003-2006 with follow-up through December 31, 2011. Five thousand five hundred seventy-five U.S. adults. Participants wore an accelerometer for at least 4 days and completed questionnaires to assess sociodemographics and chronic disease information, with blood samples taken to assess biological markers. Follow-up mortality status was assessed via death certificate data from the National Death Index. Cox proportional hazard model. After adjusting for accelerometer-determined MVPA, age, gender, race-ethnicity, cotinine, weight status, poverty level, C-reactive protein, and comorbid illness, for every 60-minute increase in accelerometer-determined light-intensity physical activity, participants had a 16% reduced hazard of all-cause mortality (hazard ratio = .84; 95% confidence interval: .78-.91; p physical activity was inversely associated with all-cause mortality risk, independent of age, MVPA, and other potential confounders. In addition to MVPA, promotion of light-intensity physical activity is warranted.

Marginal eyespots on butterfly wings deflect bird attacks under low light intensities with UV wavelengths.

Directory of Open Access Journals (Sweden)

Martin Olofsson

2010-05-01

Full Text Available Predators preferentially attack vital body parts to avoid prey escape. Consequently, prey adaptations that make predators attack less crucial body parts are expected to evolve. Marginal eyespots on butterfly wings have long been thought to have this deflective, but hitherto undemonstrated function.Here we report that a butterfly, Lopinga achine, with broad-spectrum reflective white scales in its marginal eyespot pupils deceives a generalist avian predator, the blue tit, to attack the marginal eyespots, but only under particular conditions-in our experiments, low light intensities with a prominent UV component. Under high light intensity conditions with a similar UV component, and at low light intensities without UV, blue tits directed attacks towards the butterfly head.In nature, birds typically forage intensively at early dawn, when the light environment shifts to shorter wavelengths, and the contrast between the eyespot pupils and the background increases. Among butterflies, deflecting attacks is likely to be particularly important at dawn when low ambient temperatures make escape by flight impossible, and when insectivorous birds typically initiate another day's search for food. Our finding that the deflective function of eyespots is highly dependent on the ambient light environment helps explain why previous attempts have provided little support for the deflective role of marginal eyespots, and we hypothesize that the mechanism that we have discovered in our experiments in a laboratory setting may function also in nature when birds forage on resting butterflies under low light intensities.

Marginal eyespots on butterfly wings deflect bird attacks under low light intensities with UV wavelengths.

Science.gov (United States)

Olofsson, Martin; Vallin, Adrian; Jakobsson, Sven; Wiklund, Christer

2010-05-24

Predators preferentially attack vital body parts to avoid prey escape. Consequently, prey adaptations that make predators attack less crucial body parts are expected to evolve. Marginal eyespots on butterfly wings have long been thought to have this deflective, but hitherto undemonstrated function. Here we report that a butterfly, Lopinga achine, with broad-spectrum reflective white scales in its marginal eyespot pupils deceives a generalist avian predator, the blue tit, to attack the marginal eyespots, but only under particular conditions-in our experiments, low light intensities with a prominent UV component. Under high light intensity conditions with a similar UV component, and at low light intensities without UV, blue tits directed attacks towards the butterfly head. In nature, birds typically forage intensively at early dawn, when the light environment shifts to shorter wavelengths, and the contrast between the eyespot pupils and the background increases. Among butterflies, deflecting attacks is likely to be particularly important at dawn when low ambient temperatures make escape by flight impossible, and when insectivorous birds typically initiate another day's search for food. Our finding that the deflective function of eyespots is highly dependent on the ambient light environment helps explain why previous attempts have provided little support for the deflective role of marginal eyespots, and we hypothesize that the mechanism that we have discovered in our experiments in a laboratory setting may function also in nature when birds forage on resting butterflies under low light intensities.

effect of light intensity on the cure characteristics of photo

African Journals Online (AJOL)

2012-05-05

May 5, 2012 ... Objective: To determine the light intensity emitted by light curing units (LCUs) and its effect on the cure characteristics of ... of carbon-carbon double bonds conversion (11-13). Additionally, the light intensity output of a ... increases within the unit and in the restoration. This heat not only contributes to the ...

Influence of Green, Red and Blue Light Emitting Diodes on Multiprotein Complex Proteins and Photosynthetic Activity under Different Light Intensities in Lettuce Leaves (Lactuca sativa L.

Directory of Open Access Journals (Sweden)

Sowbiya Muneer

2014-03-01

Full Text Available The objective of this study was to investigate the response of light emitting diodes (LEDs at different light intensities (70 and 80 for green LEDs, 88 and 238 for red LEDs and 80 and 238 μmol m−2 s−1 for blue LEDs at three wavelengths in lettuce leaves. Lettuce leaves were exposed to (522 nm, red (639 nm and blue (470 nm LEDs of different light intensities. Thylakoid multiprotein complex proteins and photosynthetic metabolism were then investigated. Biomass and photosynthetic parameters increased with an increasing light intensity under blue LED illumination and decreased when illuminated with red and green LEDs with decreased light intensity. The expression of multiprotein complex proteins including PSII-core dimer and PSII-core monomer using blue LEDs illumination was higher at higher light intensity (238 μmol m−2 s−1 and was lowered with decreased light intensity (70–80 μmol m−2 s−1. The responses of chloroplast sub-compartment proteins, including those active in stomatal opening and closing, and leaf physiological responses at different light intensities, indicated induced growth enhancement upon illumination with blue LEDs. High intensity blue LEDs promote plant growth by controlling the integrity of chloroplast proteins that optimize photosynthetic performance in the natural environment.

Concentration of phenolic compounds is increased in lettuce grown under high light intensity and elevated CO2.

Science.gov (United States)

Pérez-López, Usue; Sgherri, Cristina; Miranda-Apodaca, Jon; Micaelli, Francesco; Lacuesta, Maite; Mena-Petite, Amaia; Quartacci, Mike Frank; Muñoz-Rueda, Alberto

2018-02-01

The present study was focused on lettuce, a widely consumed leafy vegetable for the large number of healthy phenolic compounds. Two differently-pigmented lettuce cultivars, i.e. an acyanic-green leaf cv. and an anthocyanic-red one, were grown under high light intensity or elevated CO 2 or both in order to evaluate how environmental conditions may affect the production of secondary phenolic metabolites and, thus, lettuce quality. Mild light stress imposed for a short time under ambient or elevated CO 2 concentration increased phenolics compounds as well as antioxidant capacity in both lettuce cvs, indicating how the cultivation practice could enhance the health-promoting benefits of lettuce. The phenolic profile depended on pigmentation and the anthocyanic-red cv. always maintained a higher phenolic amount as well as antioxidant capacity than the acyanic-green one. In particular, quercetin, quercetin-3-O-glucuronide, kaempferol, quercitrin and rutin accumulated under high light or high CO 2 in the anthocyanic-red cv., whereas cyanidin derivatives were responsive to mild light stress, both at ambient and elevated CO 2 . In both cvs total free and conjugated phenolic acids maintained higher values under all altered environmental conditions, whereas luteolin reached significant amounts when both stresses were administered together, indicating, in this last case, that the enzymatic regulation of the flavonoid synthesis could be differently affected, the synthesis of flavones being favored. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Generation of intense high-order vortex harmonics.

Science.gov (United States)

Zhang, Xiaomei; Shen, Baifei; Shi, Yin; Wang, Xiaofeng; Zhang, Lingang; Wang, Wenpeng; Xu, Jiancai; Yi, Longqiong; Xu, Zhizhan

2015-05-01

This Letter presents for the first time a scheme to generate intense high-order optical vortices that carry orbital angular momentum in the extreme ultraviolet region based on relativistic harmonics from the surface of a solid target. In the three-dimensional particle-in-cell simulation, the high-order harmonics of the high-order vortex mode is generated in both reflected and transmitted light beams when a linearly polarized Laguerre-Gaussian laser pulse impinges on a solid foil. The azimuthal mode of the harmonics scales with its order. The intensity of the high-order vortex harmonics is close to the relativistic region, with the pulse duration down to attosecond scale. The obtained intense vortex beam possesses the combined properties of fine transversal structure due to the high-order mode and the fine longitudinal structure due to the short wavelength of the high-order harmonics. In addition to the application in high-resolution detection in both spatial and temporal scales, it also presents new opportunities in the intense vortex required fields, such as the inner shell ionization process and high energy twisted photons generation by Thomson scattering of such an intense vortex beam off relativistic electrons.

Construction and temporal behaviour study of multi RLC intense light pulses for dermatological applications.

Science.gov (United States)

Hamoudi, Walid K; Ismail, Raid A; Shakir, Hussein A

2017-10-01

Driving a flash lamp in an intense pulsed light system requires a high-voltage DC power supply, capacitive energy storage and a flash lamp triggering unit. Single, double, triple and quadruple-mesh discharge and triggering circuits were constructed to provide intense light pulses of variable energy and time durations. The system was treated as [Formula: see text] circuit in some cases and [Formula: see text] circuit in others with a light pulse profile following the temporal behaviour of the exciting current pulse. Distributing the energy delivered to one lamp onto a number of LC meshes permitted longer current pulses, and consequently increased the light pulse length. Positive results were obtained when using the system to treat skin wrinkles.

Effects of alkalinity and salinity at low and high light intensity on hydrogen isotope fractionation of long-chain alkenones produced by Emiliania huxleyi

Directory of Open Access Journals (Sweden)

G. M. Weiss

2017-12-01

Full Text Available Over the last decade, hydrogen isotopes of long-chain alkenones have been shown to be a promising proxy for reconstructing paleo sea surface salinity due to a strong hydrogen isotope fractionation response to salinity across different environmental conditions. However, to date, the decoupling of the effects of alkalinity and salinity, parameters that co-vary in the surface ocean, on hydrogen isotope fractionation of alkenones has not been assessed. Furthermore, as the alkenone-producing haptophyte, Emiliania huxleyi, is known to grow in large blooms under high light intensities, the effect of salinity on hydrogen isotope fractionation under these high irradiances is important to constrain before using δDC37 to reconstruct paleosalinity. Batch cultures of the marine haptophyte E. huxleyi strain CCMP 1516 were grown to investigate the hydrogen isotope fractionation response to salinity at high light intensity and independently assess the effects of salinity and alkalinity under low-light conditions. Our results suggest that alkalinity does not significantly influence hydrogen isotope fractionation of alkenones, but salinity does have a strong effect. Additionally, no significant difference was observed between the fractionation responses to salinity recorded in alkenones grown under both high- and low-light conditions. Comparison with previous studies suggests that the fractionation response to salinity in culture is similar under different environmental conditions, strengthening the use of hydrogen isotope fractionation as a paleosalinity proxy.

Effects of alkalinity and salinity at low and high light intensity on hydrogen isotope fractionation of long-chain alkenones produced by Emiliania huxleyi

Science.gov (United States)

Weiss, Gabriella M.; Pfannerstill, Eva Y.; Schouten, Stefan; Sinninghe Damsté, Jaap S.; van der Meer, Marcel T. J.

2017-12-01

Over the last decade, hydrogen isotopes of long-chain alkenones have been shown to be a promising proxy for reconstructing paleo sea surface salinity due to a strong hydrogen isotope fractionation response to salinity across different environmental conditions. However, to date, the decoupling of the effects of alkalinity and salinity, parameters that co-vary in the surface ocean, on hydrogen isotope fractionation of alkenones has not been assessed. Furthermore, as the alkenone-producing haptophyte, Emiliania huxleyi, is known to grow in large blooms under high light intensities, the effect of salinity on hydrogen isotope fractionation under these high irradiances is important to constrain before using δDC37 to reconstruct paleosalinity. Batch cultures of the marine haptophyte E. huxleyi strain CCMP 1516 were grown to investigate the hydrogen isotope fractionation response to salinity at high light intensity and independently assess the effects of salinity and alkalinity under low-light conditions. Our results suggest that alkalinity does not significantly influence hydrogen isotope fractionation of alkenones, but salinity does have a strong effect. Additionally, no significant difference was observed between the fractionation responses to salinity recorded in alkenones grown under both high- and low-light conditions. Comparison with previous studies suggests that the fractionation response to salinity in culture is similar under different environmental conditions, strengthening the use of hydrogen isotope fractionation as a paleosalinity proxy.

Automated system for the determination of patterns of high-intensity LEDs

International Nuclear Information System (INIS)

Baly, L.; Bolaño, L.; Arteche, R.; Broco, Y.; Quesada, I.; Rodríguez, E.

2008-01-01

Determination of high-intensity LEDs lighting patterns is an important step for the simulation and planning of arrays of these devices configurations. Currently there are systems based on CCD cameras able to efficiently solve this problem, however the high cost of these is a limiting factor for use. Another limitation of CCD cameras, is that they are designed for light levels much lower than those produced by a high-intensity LED. In this paper we present an automated system for the determination of the intensity of LEDs based on the scan point to point patterns. The results of the analysis of a type of LED based on arrays of bars with built-in optical system is presented.

Effects of Light Intensity and Color on the Biomass, Extracellular Red Pigment, and Citrinin Production of Monascus ruber.

Science.gov (United States)

Wang, Liling; Dai, Yang; Chen, Wanping; Shao, Yanchun; Chen, Fusheng

2016-12-21

Light is a crucial environmental signal for fungi. In this work, the effects of different light intensities and colors on biomass, Monascus pigments (MPs) and citrinin production of Monascus ruber M7 were investigated. We have demonstrated that low intensity of blue light (500 lx) decreased Monascus biomass, increased MPs accumulation via upregulation of MpigA, MpigB, and MpigJ genes expression, but had no significant influence on citrinin production. High intensity of blue light (1500 lx) decreased citrinin accumulation but had no significant influence on biomass and MPs production after 14 days cultivation. Low intensity of green light (500 lx) stimulated citrinin production via upregulation of pksCT, mrl1, mrl2, and ctnA genes expression. One putative red light photoreceptor and two putative green light photoreceptors were identified in M. ruber M7. These observations will not only guide the practical production of Monascus but also contribute to our understanding light effects on Monascus.

Light intensity modulates the response of two Antarctic diatom species to ocean acidification

Directory of Open Access Journals (Sweden)

Jasmin Pascale Heiden

2016-12-01

Full Text Available It is largely unknown how rising atmospheric CO2 concentrations and changes in the upper mixed layer depth, with its subsequent effects on light availability will affect phytoplankton physiology in the Southern Ocean. Linking seasonal variations in the availability of CO2 and light to abundances and physiological traits of key phytoplankton species could aid to understand their abilities to acclimate to predicted future climatic conditions. To investigate the combined effects of CO2 and light on two ecologically relevant Antarctic diatoms (Fragilariopsis curta and Odontella weisflogii a matrix of three light intensities (LL=20, ML=200, HL=500 µmol photons m-2 s-1 and three pCO2 levels (low=180, ambient=380, high=1000 µatm was applied assessing their effects on growth, particulate organic carbon (POC fixation and photophysiology. Under ambient pCO2, POC production rates were highest already at low light in Fragilariopsis, indicating saturation of photosynthesis, while in Odontella highest rates were only reached at medium irradiances. In both species ocean acidification did not stimulate, but rather inhibited, growth and POC production under low and medium light. This effect was, however, amended under high growth irradiances. Low pCO2 levels inhibited growth and POC production in both species at low and medium light, and further decreased absETRs under high light. Our results suggest that Southern Ocean diatoms were sensitive to changes in pCO2, showing species-specific responses, which were further modulated by light intensity. The two diatom species represent distinct ecotypes and revealed discrete physiological traits that matched their seasonal occurrence with the related physical conditions in Antarctic coastal waters.

Effects of four dim vs high intensity red color light regimens on growth performance and welfare of broilers.

Science.gov (United States)

Senaratna, D; Samarakone, T S; Gunawardena, W W D A

2018-01-01

Broilers show clear preference towards red color light (RL). However setting of an optimum light intensity is difficult since dim intensities that favor growth reduce welfare. This experiment was conducted to test the most effective RL intensity regimen (Dim [5 lux; DI] vs high [320 lux; HI]) in combination applied at different growth stages that favors for both performance and welfare. Complete randomize design was adopted with 6 replicates. Treatments were; T1 = early DI (8-21 d)+latter HI (22-35 d); T2 = early DI (8-28 d)+latter HI (29-35 d), T3 = early HI (8-21 d)+latter DI (22-35 d), T4 = early HI (8-28 d)+latter DI (29-35 d) and T5 = control (white light; WT) (8-35 d) at medium intensity (20 lux). Body weight (BW), weight gain (WG), water/feed intake and ratio, feed conversion ratios (FCR) were assessed. Common behaviours (15) were recorded by scan sampling method. Lameness, foot pad dermatitis, breast blisters, hock burning damage were assessed as welfare parameters. Fear reactions were tested using Tonic Immobility Test. Ocular and carcass evaluations were done. Meat and tibiae were analyzed for fat and bone ash respectively. On 35 d, the highest BW (2,155.72±176 g), WG (1,967.78±174 g) were recorded by T2 compared to WT (BW WT = 1,878.22±155, WG WT = 1,691.83±160). But, application of RL, either DI, or HI during early/latter stage had no significant effect on FCR. Under HI, birds showed much higher active behaviours. DI encourages eating. Though LI changed from DI to HI, same trend could be seen even under HI. The highest leg strength (218.5±120 s) was recorded by T2. The lowest leg strength (64.58±33 s) and the highest ocular weight (2.48±1 g) were recorded by T1. Significantly (plighting regimen for optimizing production, better welfare of broilers and improving health benefits of meat.

Photooptical response of the blood plasma to the low-intensity red light

International Nuclear Information System (INIS)

Mints, R.I.; Skopinov, S.A.; Yakovleva, S.V.

1990-01-01

Photooptical response to low-intensity red light by irradiation of the whole blood as well as of its pigmentless plasma part is investigated. It is shown by the example of blood irradiation that the mechanism of action of low-intensity red light on the blood is not directly related to pigmented molecular complexes. The conclusion is made, that the effect of low-intensity red light on living organisms includes mechanism not utilizing light absorption by a specialized molecule-photoreceptor as a primary photophysical act

Laser and intense pulsed light hair removal technologies

DEFF Research Database (Denmark)

Haedersdal, M; Beerwerth, F; Nash, J F

2011-01-01

Light-based hair removal (LHR) is one of the fastest growing, nonsurgical aesthetic cosmetic procedures in the United States and Europe. A variety of light sources including lasers, e.g. alexandrite laser (755 nm), pulsed diode lasers (800, 810 nm), Nd:YAG laser (1064 nm) and broad-spectrum intense...

Nonlinear behavior in high-intensity discharge lamps

NARCIS (Netherlands)

Baumann, Bernd; Schwieger, Joerg; Wolff, Marcus; Manders, Freddy; Suijker, Jos

2016-01-01

The light flicker problem of high intensity discharge lamps is studied numerically and experimentally. It is shown that in some respects the systems behave very similar to the forced Duffing oscillator with a softening spring. In particular, the jump phenomenon and hysteresis are observed in the

Very high intensity reaction chamber design

International Nuclear Information System (INIS)

Devaney, J.J.

1975-09-01

The problem of achieving very high intensity irradiation by light in minimal regions was studied. Three types of irradiation chamber are suggested: the common laser-reaction chamber, the folded concentric or near-concentric resonator, and the asymmetric confocal resonator. In all designs the ratio of high-intensity illuminated volume to other volume is highly dependent (to the 3 / 2 power) on the power and fluence tolerances of optical elements, primarily mirrors. Optimization of energy coupling is discussed for the common cavity. For the concentric cavities, optimization for both coherent and incoherent beams is treated. Formulae and numerical examples give the size of chambers, aspect ratios, maximum pass number, image sizes, fluences, and the like. Similarly for the asymmetric confocal chamber, formulae and numerical examples for fluences, dimensions, losses, and totally contained pass numbers are given

Effects of four dim vs high intensity red color light regimens on growth performance and welfare of broilers

Directory of Open Access Journals (Sweden)

D. Senaratna

2018-01-01

Full Text Available Objective Broilers show clear preference towards red color light (RL. However setting of an optimum light intensity is difficult since dim intensities that favor growth reduce welfare. This experiment was conducted to test the most effective RL intensity regimen (Dim [5 lux; DI] vs high [320 lux; HI] in combination applied at different growth stages that favors for both performance and welfare. Methods Complete randomize design was adopted with 6 replicates. Treatments were; T1 = early DI (8–21 d+latter HI (22–35 d; T2 = early DI (8–28 d+latter HI (29–35 d, T3 = early HI (8–21 d+latter DI (22–35 d, T4 = early HI (8–28 d+latter DI (29–35 d and T5 = control (white light; WT (8–35 d at medium intensity (20 lux. Body weight (BW, weight gain (WG, water/feed intake and ratio, feed conversion ratios (FCR were assessed. Common behaviours (15 were recorded by scan sampling method. Lameness, foot pad dermatitis, breast blisters, hock burning damage were assessed as welfare parameters. Fear reactions were tested using Tonic Immobility Test. Ocular and carcass evaluations were done. Meat and tibiae were analyzed for fat and bone ash respectively. Results On 35 d, the highest BW (2,155.72±176 g, WG (1,967.78±174 g were recorded by T2 compared to WT (BWWT = 1,878.22±155, WGWT = 1,691.83±160. But, application of RL, either DI, or HI during early/latter stage had no significant effect on FCR. Under HI, birds showed much higher active behaviours. DI encourages eating. Though LI changed from DI to HI, same trend could be seen even under HI. The highest leg strength (218.5±120 s was recorded by T2. The lowest leg strength (64.58±33 s and the highest ocular weight (2.48±1 g were recorded by T1. Significantly (p<0.05 the highest skin weight (162.17±6 g but the lowest fat% in meat (13.03%±5% was recorded by T2. Conclusion Early exposure to DI-RL up to 28 days followed by exposure to HI-RL is the most favorable lighting regimen for

Stolephorus sp Behavior in Different LED (Light Emitting Diode) Color and Light Intensities

Science.gov (United States)

Fitri Aristi, D. P.; Ramadanita, I. A.; Hapsari, T. D.; Susanto, A.

2018-02-01

This research aims to observe anchovy (Stolephorus sp) behavior under different LED light intensities that affect eye physiology (cell cone structure). The materials used were Stolephorus sp taken from the waters off Jepara and 13 and 10 watt light emitting diode (LED). The research method was an experiment conducted from March through August 2015 in the waters off Jepara. Data analysis of visual histology and fish respond was carried out at the fishing gear material laboratory, anatomy and cultivate. Cone cell structure (mosaic cone) of Stolephorus sp forms a connected regular square pattern with every single cone surrounded by four double cones, which indicate that anchovies are sensitive to light. The 13 watt LED (628 lux) has faster response than the 10 watt LED (531 lux) as it has wider and higher emitting intensity, which also attracts fish to gather quicker.

Low-intensity blue-enriched white light (750 lux) and standard bright light (10,000 lux) are equally effective in treating SAD. A randomized controlled study.

Science.gov (United States)

Meesters, Ybe; Dekker, Vera; Schlangen, Luc J M; Bos, Elske H; Ruiter, Martine J

2011-01-28

Photoreceptor cells containing melanopsin play a role in the phase-shifting effects of short-wavelength light. In a previous study, we compared the standard light treatment (SLT) of SAD with treatment using short-wavelength blue-enriched white light (BLT). Both treatments used the same illuminance (10,000 lux) and were equally highly effective. It is still possible, however, that neither the newly-discovered photoreceptor cells, nor the biological clock play a major role in the therapeutic effects of light on SAD. Alternatively, these effects may at least be partly mediated by these receptor cells, which may have become saturated as a result of the high illuminances used in the therapy. This randomized controlled study compares the effects of low-intensity BLT to those of high-intensity SLT. In a 22-day design, 22 patients suffering from a major depression with a seasonal pattern (SAD) were given light treatment (10,000 lux) for two weeks on workdays. Subjects were randomly assigned to either of the two conditions, with gender and age evenly distributed over the groups. Light treatment either consisted of 30 minutes SLT (5000 °K) with the EnergyLight® (Philips, Consumer Lifestyle) with a vertical illuminance of 10,000 lux at eye position or BLT (17,000 °K) with a vertical illuminance of 750 lux using a prototype of the EnergyLight® which emitted a higher proportion of short-wavelengths. All participants completed questionnaires concerning mood, activation and sleep quality on a daily basis. Mood and energy levels were also assessed on a weekly basis by means of the SIGH-SAD and other assessment tools. On day 22, SIGH-SAD ratings were significantly lower than on day 1 (SLT 65.2% and BLT 76.4%). On the basis of all assessments no statistically significant differences were found between the two conditions. With sample size being small, conclusions can only be preliminary. Both treatment conditions were found to be highly effective. The therapeutic effects of low-intensity

Low-intensity blue-enriched white light (750 lux and standard bright light (10 000 lux are equally effective in treating SAD. A randomized controlled study

Directory of Open Access Journals (Sweden)

Bos Elske H

2011-01-01

Full Text Available Abstract Background Photoreceptor cells containing melanopsin play a role in the phase-shifting effects of short-wavelength light. In a previous study, we compared the standard light treatment (SLT of SAD with treatment using short-wavelength blue-enriched white light (BLT. Both treatments used the same illuminance (10 000 lux and were equally highly effective. It is still possible, however, that neither the newly-discovered photoreceptor cells, nor the biological clock play a major role in the therapeutic effects of light on SAD. Alternatively, these effects may at least be partly mediated by these receptor cells, which may have become saturated as a result of the high illuminances used in the therapy. This randomized controlled study compares the effects of low-intensity BLT to those of high-intensity SLT. Method In a 22-day design, 22 patients suffering from a major depression with a seasonal pattern (SAD were given light treatment (10 000 lux for two weeks on workdays. Subjects were randomly assigned to either of the two conditions, with gender and age evenly distributed over the groups. Light treatment either consisted of 30 minutes SLT (5000°K with the EnergyLight® (Philips, Consumer Lifestyle with a vertical illuminance of 10 000 lux at eye position or BLT (17 000°K with a vertical illuminance of 750 lux using a prototype of the EnergyLight® which emitted a higher proportion of short-wavelengths. All participants completed questionnaires concerning mood, activation and sleep quality on a daily basis. Mood and energy levels were also assessed on a weekly basis by means of the SIGH-SAD and other assessment tools. Results On day 22, SIGH-SAD ratings were significantly lower than on day 1 (SLT 65.2% and BLT 76.4%. On the basis of all assessments no statistically significant differences were found between the two conditions. Conclusion With sample size being small, conclusions can only be preliminary. Both treatment conditions were found

Current indications and new applications of intense pulsed light.

Science.gov (United States)

González-Rodríguez, A J; Lorente-Gual, R

2015-06-01

Intense pulsed light (IPL) systems have evolved since they were introduced into medical practice 20 years ago. Pulsed light is noncoherent, noncollimated, polychromatic light energy emitted at different wavelengths that target specific chromophores. This selective targeting capability makes IPL a versatile therapy with many applications, from the treatment of pigmented or vascular lesions to hair removal and skin rejuvenation. Its large spot size ensures a high skin coverage rate. The nonablative nature of IPL makes it an increasingly attractive alternative for patients unwilling to accept the adverse effects associated with other procedures, which additionally require prolonged absence from work and social activities. In many cases, IPL is similar to laser therapy in effectiveness, and its versatility, convenience, and safety will lead to an expanded range of applications and possibilities in coming years. Copyright © 2014 Elsevier España, S.L.U. and AEDV. All rights reserved.

Preferency of soil macrofauna to crops residue at different light intensity

Directory of Open Access Journals (Sweden)

SUGIYARTO

2007-10-01

Full Text Available Every species of soil macrofauna prefer specific food and environment to be establish in it's habitat. Their diversity depend on variation of food and environmental condition. The aim of this research was to study the effect of different crop residue and light intensity on population of several soil macrofauna specieses. Mycrocosmos experiment was arranged in split-plot design with two treatments factor, i.e.: (1 crop residue (albizia, papaya, elephant grass, maize, sweet potato and without crop residue input, and (2 light intensities (0, 5, 15 and 25 Watt/day. The soil macrofauna were earthworms, millipedes, scarabids larvae and cocroachs. Results of the study showed that: (1 crop residues apllication increased soil macrofauna population, especially maize residue ( by 113%, respectively, compare to control tretment, (2 on higher light intensity, population of earthworms, scarabids larvae and cocroach decreased, but population of millipedes increased, (3 the highest macrofauna population was on maize residue and 5 Watt/day light intensity treatment.

Acclimation strategy of Rhodopseudomonas palustris to high light irradiance.

Science.gov (United States)

Muzziotti, Dayana; Adessi, Alessandra; Faraloni, Cecilia; Torzillo, Giuseppe; De Philippis, Roberto

2017-04-01

The ability of Rhodopseudomonas palustris cells to rapidly acclimate to high light irradiance is an essential issue when cells are grown under sunlight. The aim of this study was to investigate the photo-acclimation process in Rhodopseudomonas palustris 42OL under different culturing conditions: (i) anaerobic (AnG), (ii) aerobic (AG), and (iii) under H 2 -producing (HP) conditions both at low (LL) and high light (HL) irradiances. The results obtained clearly showed that the photosynthetic unit was significantly affected by the light irradiance at which Rp. palustris 42OL was grown. The synthesis of carotenoids was affected by both illumination and culturing conditions. At LL, lycopene was the main carotenoid synthetized under all conditions tested, while at HL under HP conditions, it resulted the predominant carotenoid. Oppositely, under AnG and AG at HL, rhodovibrin was the major carotenoid detected. The increase in light intensity produced a deeper variation in light-harvesting complexes (LHC) ratio. These findings are important for understanding the ecological distribution of PNSB in natural environments, mostly characterized by high light intensities, and for its growth outdoors. Copyright © 2017 Elsevier GmbH. All rights reserved.

Carcinogenesis related to intense pulsed light and UV exposure

DEFF Research Database (Denmark)

Hedelund, L; Lerche, C; Wulf, H C

2006-01-01

This study examines whether intense pulsed light (IPL) treatment has a carcinogenic potential itself or may influence ultraviolet (UV)-induced carcinogenesis. Secondly, it evaluates whether UV exposure may influence IPL-induced side effects. Hairless, lightly pigmented mice (n=144) received three...

Nonlinear behavior in high-intensity discharge lamps

Science.gov (United States)

Baumann, Bernd; Schwieger, Joerg; Wolff, Marcus; Manders, Freddy; Suijker, Jos

2016-06-01

The light flicker problem of high intensity discharge lamps is studied numerically and experimentally. It is shown that in some respects the systems behave very similar to the forced Duffing oscillator with a softening spring. In particular, the jump phenomenon and hysteresis are observed in the simulations and in the experiments.

Effect of oxygen at low and high light intensities on the growth of Neochloris oleoabundans

NARCIS (Netherlands)

Sousa, C.A.; Compadre, A.; Vermuë, M.H.; Wijffels, R.H.

2013-01-01

The effect of partial oxygen pressure on growth of Neochloris oleoabundans was studied at near-saturating light intensity in a fully-controlled photobioreactor. At the partial oxygen pressures tested (PO2=0.24; 0.42; 0.63; 0.84 bar), the specific growth rate was 1.36; 1.16; 0.93 and 0.68 day-1,

Third-order optical intensity correlation measurements of pseudo-thermal light

International Nuclear Information System (INIS)

Chen Xi-Hao; Wu Wei; Meng Shao-Ying; Li Ming-Fei

2014-01-01

Third-order Hanbrury Brown—Twiss and double-slit interference experiments with a pseudo-thermal light are performed by recording intensities in single, double and triple optical paths, respectively. The experimental results verifies the theoretical prediction that the indispensable condition for achieving a interference pattern or ghost image in Nth-order intensity correlation measurements is the synchronous detection of the same light field by each reference detector, no matter the intensities recorded in one, or two, or N optical paths. It is shown that, when the reference detectors are scanned in the opposite directions, the visibility and resolution of the third-order spatial correlation function of thermal light is much better than that scanned in the same direction, but it is no use for obtaining the Nth-order interference pattern or ghost image in the thermal Nth-order interference or ghost imaging. (general)

Fast algal eco-toxicity assessment: Influence of light intensity and exposure time on Chlorella vulgaris inhibition by atrazine and DCMU.

Science.gov (United States)

Camuel, Alexandre; Guieysse, Benoit; Alcántara, Cynthia; Béchet, Quentin

2017-06-01

In order to develop a rapid assay suitable for algal eco-toxicity assessments under conditions representative of natural ecosystems, this study evaluated the short-term (Chlorella vulgaris was exposed to these herbicides under 'standard' low light intensity (as prescribed by OECD201 guideline), the 20min-EC 50 values recorded via oxygen productivity (atrazine: 1.32±0.07μM; DCMU: 0.31±0.005μM) were similar the 96-h EC 50 recorded via algal growth (atrazine: 0.56μM; DCMU: 0.41μM), and within the range of values reported in the literature. 20min-EC50 values increased by factors of 3.0 and 2.1 for atrazine and DCMU, respectively, when light intensity increased from 60 to 1400μmolm -2 s -1 of photosynthetically active radiation, or PAR. Further investigation showed that exposure time significantly also impacted the sensitivity of C. vulgaris under high light intensity (>840μmolm -2 s -1 as PAR) as the EC 50 for atrazine and DCMU decreased by up to 6.2 and 2.1 folds, respectively, after 50min of exposure at a light irradiance of 1400μmolm -2 s -1 as PAR. This decrease was particularly marked at high light intensities and low algae concentrations and is explained by the herbicide disruption of the electron transfer chain triggering photo-inhibition at high light intensities. Eco-toxicity assessments aiming to understand the potential impact of toxic compounds on natural ecosystems should therefore be performed over sufficient exposure times (>20min for C. vulgaris) and under light intensities relevant to these ecosystems. Copyright © 2017 Elsevier Inc. All rights reserved.

Red Color Light at Different Intensities Affects the Performance, Behavioral Activities and Welfare of Broilers

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D. Senaratna

2016-07-01

Full Text Available Red light (RL marked higher weight gain (WG and preference of broilers compared to other light colors. This study aimed to investigate how different intensities of RL affect the performance, behavior and welfare of broilers. RL treatments were T1 = high intensity (320 lux, T2 = medium intensity (20 lux; T3 = dim intensity (5 lux, T4 = control/white light at (20 lux provided on 20L:4D schedule and T5 = negative control; 12 hours dark: 12 hours day light. Cobb strain broilers were used in a Complete Randomize Design with 6 replicates. WG, water/feed intake, feed conversion ratio (FCR, mortality, behavior and welfare were assessed. At 35 d, significantly (p<0.05 highest body weight (2,147.06 g±99 was recorded by T3. Lowest body weight (1,640.55 g±56 and FCR (1.34 were recorded by T5. Skin weight was the only carcass parameter showed a significant (p<0.05 influence giving the highest (56.2 g and the lowest (12.6 g values for T5 and T1 respectively. Reduced welfare status indicated by significantly (p<0.05 higher foot pad lesions, hock burns and breast blisters was found under T3, due to reduced expression of behavior. Highest walking (2.08%±1% was performed under T1 in the evening during 29 to 35 days. Highest dust bathing (3.01%±2% was performed in the morning during 22 to 28 days and highest bird interaction (BI (4.87%±4% was observed in the evening by T5 during 14 to 21 days. Light intensity×day session×age interaction was significantly (p<0.05 affected walking, dust bathing and BI. Light intensity significantly (p<0.05 affected certain behaviors such as lying, eating, drinking, standing, walking, preening while lying, wing/leg stretching, sleeping, dozing, BI, vocalization, idling. In conclusion, birds essentially required provision of light in the night for better performance. Exposed to 5 lux contributed to higher WG, potentially indicating compromised welfare status. Further researches are suggested to investigate RL intensity based

The high intensity solar cell: Key to low cost photovoltaic power

Science.gov (United States)

Sater, B. L.; Goradia, C.

1975-01-01

The design considerations and performance characteristics of the 'high intensity' (HI) solar cell are presented. A high intensity solar system was analyzed to determine its cost effectiveness and to assess the benefits of further improving HI cell efficiency. It is shown that residential sized systems can be produced at less than $1000/kW peak electric power. Due to their superior high intensity performance characteristics compared to the conventional and VMJ cells, HI cells and light concentrators may be the key to low cost photovoltaic power.

Pigment variations in Emiliania huxleyi (CCMP370) as a response to changes in light intensity or quality.

Science.gov (United States)

Garrido, José L; Brunet, Christophe; Rodríguez, Francisco

2016-12-01

Many studies on photoacclimation examine the pigment responses to changes in light intensity, but variations in light climate in the aquatic environment are also related to changes in spectral composition. We have employed a high-performance liquid chromatography method with improved resolution towards chlorophyll c and fucoxanthin-related xanthophylls to examine the pigment composition of Emiliania huxleyi CCMP 370 under different light intensities and spectral qualities. To maintain its photosynthetic performance, E. huxleyi CCMP370 promotes drastic pigment changes that can be either the interconversion of pigments in pools with the same basic chromophoric structure (Fucoxanthin type or chlorophyll c type), or the ex novo synthesis (Diatoxanthin). These changes are linked either to variations in light quality (Fucoxanthin related xanthophylls) or in light intensity (chlorophyll c 3 /Monovinyl chlorophyll c 3 , Diadinoxanthin/Diatoxanthin, β,ɛ-carotene/ β,β-carotene). Fucoxanthin and 19'-hexanoyloxyfucoxanthin proportions were highly dependent on spectral conditions. Whereas Fucoxanthin dominated in green and red light, 19'-hexanoyloxyfucoxanthin prevailed under blue spectral conditions. Our results suggest that the huge pigment diversity enhanced the photoacclimative capacities of E. huxleyi to efficiently perform under changing light environments. The ubiquity and success in the global ocean as well as the capacity of E. huxleyi to form large surface blooms might be associated to the plasticity described here. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

LED Lighting – Modification of Growth, Metabolism, Yield and Flour Composition in Wheat by Spectral Quality and Intensity

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István Monostori

2018-05-01

Full Text Available The use of light-emitting diode (LED technology for plant cultivation under controlled environmental conditions can result in significant reductions in energy consumption. However, there is still a lack of detailed information on the lighting conditions required for optimal growth of different plant species and the effects of light intensity and spectral composition on plant metabolism and nutritional quality. In the present study, wheat plants were grown under six regimens designed to compare the effects of LED and conventional fluorescent lights on growth and development, leaf photosynthesis, thiol and amino acid metabolism as well as grain yield and flour quality of wheat. Benefits of LED light sources over fluorescent lighting were manifested in both yield and quality of wheat. Elevated light intensities made possible with LEDs increased photosynthetic activity, the number of tillers, biomass and yield. At lower light intensities, blue, green and far-red light operated antagonistically during the stem elongation period. High photosynthetic activity was achieved when at least 50% of red light was applied during cultivation. A high proportion of blue light prolonged the juvenile phase, while the shortest flowering time was achieved when the blue to red ratio was around one. Blue and far-red light affected the glutathione- and proline-dependent redox environment in leaves. LEDs, especially in Blue, Pink and Red Low Light (RedLL regimens improved flour quality by modifying starch and protein content, dough strength and extensibility as demonstrated by the ratios of high to low molecular weight glutenins, ratios of glutenins to gliadins and gluten spread values. These results clearly show that LEDs are efficient for experimental wheat cultivation, and make it possible to optimize the growth conditions and to manipulate metabolism, yield and quality through modification of light quality and quantity.

Effect of light intensity and initial pH during hydrogen production by an integrated dark and photofermentation process

Energy Technology Data Exchange (ETDEWEB)

Nath, Kaushik [Department of Chemical Engineering, GH Patel College of Engineering and Technology, Vallabh Vidyanagar 388 120, Gujarat (India); Das, Debabrata [Fermentation Technology Laboratory, Department of Biotechnology, Indian Institute of Technology, Kharagpur 721302 (India)

2009-09-15

Photofermentation was carried out with the spent fermentation broth obtained from the anaerobic dark fermentation in a two-stage process. For the first stage, i.e. dark fermentation Enterobacter cloacae DM 11 was used as hydrogen producing microorganism. For photofermentation Rhodobacter sphaeroides O.U. 001, a photo-heterotrophic purple non-sulfur bacterium, was used. pH study revealed that cumulative hydrogen production was maximum at initial medium pH of 7.0 {+-} 0.2. Biomass yield was also high at the vicinity of pH 7.0 and it decreased as the pH increased from 7.0 to 8.0. Increased light intensity resulted in an increase in the total volume of hydrogen evolved and also hydrogen production rate. However, light conversion efficiency decreased by increasing light intensity. A four-fold increase in light intensity resulted in a three-fold decrease in light conversion efficiency although the cumulative volume of hydrogen gas production increased. It was observed that only a maximum of 0.51% light conversion efficiency could be achieved but at the expense of very low light intensity of 2500 lux (3.75 W m{sup -2}). (author)

The role of lasers and intense pulsed light technology in dermatology

Directory of Open Access Journals (Sweden)

Husain Z

2016-02-01

Full Text Available Zain Husain,1 Tina S Alster1,2 1Department of Dermatology, Georgetown University Hospital, 2Washington Institute of Dermatologic Laser Surgery, Washington, DC, USA Abstract: The role of light-based technologies in dermatology has expanded dramatically in recent years. Lasers and intense pulsed light have been used to safely and effectively treat a diverse array of cutaneous conditions, including vascular and pigmented lesions, tattoos, scars, and undesired hair, while also providing extensive therapeutic options for cosmetic rejuvenation and other dermatologic conditions. Dermatologic laser procedures are becoming increasingly popular worldwide, and demand for them has fueled new innovations and clinical applications. These systems continue to evolve and provide enhanced therapeutic outcomes with improved safety profiles. This review highlights the important roles and varied clinical applications that lasers and intense pulsed light play in the dermatologic practice. Keywords: laser, intense pulsed light, treatment, dermatology, technology

Temperature and light intensity interaction on Cercospora coffeicola sporulation and conidia germination

Directory of Open Access Journals (Sweden)

Marília Goulart da Silva

2016-04-01

Full Text Available ABSTRACT Difficulty in obtaining abundant sporulation in culture of many species of Cercospora may be the limiting factor for studies of biology, systematics, and inoculation of the genus. Therefore, it is necessary to understand the nutritional and environmental requirements that influence mycelial growth, sporulation and germination. As it is difficult to obtain conidia of Cercospora coffeicola in vitro, different temperatures (17, 22, 27, and 32 °C and light intensities (80, 160, 240, and 320 μmol m-2 s-1 were evaluated to optimize pathogen sporulation and assess favorable conditions for spore germination, aiming for a strategy of disease control. The dark treatment (0 μmol m-2 s-1 was added for sporulation. A significant interaction was found between temperature and light intensity for both variables. The highest sporulation rate of C. coffeicola occurred at a light intensity of 240 μmol m-2 s-1 and air temperature of 22 °C, reaching 5.9x106 con mL-1. Germination was higher at temperature 17 °C and light intensity of 320 μmol m-2 s-1, reaching 52%. Interaction between light intensity and temperature proved to influence the processes of sporulation and germination of C. coffeicola.

High-angle scattering events strongly affect light collection in clinically relevant measurement geometries for light transport through tissue

International Nuclear Information System (INIS)

Canpolat, M.; Mourant, J.R.

2000-01-01

Measurement of light transport in tissue has the potential to be an inexpensive and practical tool for non-invasive tissue diagnosis in medical applications because it can provide information on both morphological and biochemical properties. To capitalize on the potential of light transport as a diagnostic tool, an understanding of what information can be gleaned from light transport measurements is needed. We present data concerning the sensitivity of light transport measurements, made in clinically relevant geometries, to scattering properties. The intensity of the backscattered light at small source-detector separations is shown to be sensitive to the phase function, and furthermore the collected light intensity is found to be correlated with the amount of high-angle scattering in the medium. (author)

Growth of the microalgae Neochloris oleoabundans at high partial oxygen pressures and sub-saturating light intensity.

Science.gov (United States)

Sousa, Cláudia; de Winter, Lenneke; Janssen, Marcel; Vermuë, Marian H; Wijffels, René H

2012-01-01

The effect of partial oxygen pressure on growth of Neochloris oleoabundans was studied at sub-saturating light intensity in a fully-controlled stirred tank photobioreactor. At the three partial oxygen pressures tested (P(O)₂= 0.24; 0.63; 0.84 bar), the specific growth rate was 1.38; 1.36 and 1.06 day(-1), respectively. An increase of the P(CO)₂from 0.007 to 0.02 bar at P(O₂) of 0.84 bar resulted in an increase in the growth rate from 1.06 to 1.36 day(-1). These results confirm that the reduction of algal growth at high oxygen concentrations at sub-saturating light conditions is mainly caused by competitive inhibition of Rubisco. This negative effect on growth can be overcome by restoring the O(2)/CO(2) ratio by an increase in the partial carbon dioxide pressure. In comparison to general practice (P(O(2)) = 0.42 bar), working at partial O(2) pressure of 0.84 bar could reduce the energy requirement for degassing by a factor of 3-4. Copyright © 2011 Elsevier Ltd. All rights reserved.

Early Birds by Light at Night: Effects of Light Color and Intensity on Daily Activity Patterns in Blue Tits

NARCIS (Netherlands)

de Jong, Maaike; Caro, Samuel P.; Gienapp, Phillip; Spoelstra, Kamiel; Visser, Marcel E.

2017-01-01

Artificial light at night disturbs the daily rhythms of many organisms. To what extent this disturbance depends on the intensity and spectral composition of light remain obscure. Here, we measured daily activity patterns of captive blue tits (Cyanistes caeruleus) exposed to similar intensities of

Growth of the microalgae Neochloris oleoabundans at high partial oxygen pressures and sub-saturating light intensity

NARCIS (Netherlands)

Sousa, C.A.; Winter, de L.; Janssen, M.G.J.; Vermue, M.H.; Wijffels, R.H.

2012-01-01

The effect of partial oxygen pressure on growth of Neochloris oleoabundans was studied at sub-saturating light intensity in a fully-controlled stirred tank photobioreactor. At the three partial oxygen pressures tested (PO2=0.24; 0.63; 0.84 bar), the specific growth rate was 1.38; 1.36 and 1.06

The effect of spectral property and intensity of light on natural refractive development and compensation to negative lenses in guinea pigs.

Science.gov (United States)

Li, Wentao; Lan, Weizhong; Yang, Shiqi; Liao, Yunru; Xu, Qinglin; Lin, Lixia; Yang, Zhikuan

2014-10-02

To investigate the effect of spectral composition and light intensity on refractive development in guinea pigs. One-week-old guinea pigs were randomly assigned to groups exposed to broad-spectrum Solux halogen light (BS) or spiked-spectrum fluorescent light (FL) at both high (Hi, 10,000 lux) and low (Lo, 500 lux) intensities under a 12:12 light/dark cycle. Half of the animals in each group were used as controls (n = 24, 20, 22, and 20, respectively), and half were fitted with binocular -4-diopter (D) lenses (L, lenses; n = 22, 20, 24, and 22, respectively). Refractive error, corneal curvature, and axial dimensions were determined by cycloplegic retinoscopy, photokeratometry, and A-scan ultrasonography, respectively. Guinea pigs exposed to FL and BS showed similar changes in refraction under both high (HiFL: 2.26 ± 0.55 D versus HiBS: 2.17 ± 0.65 D, P > 0.05)- and low-intensity lighting (LoFL: 1.39 ± 0.88 D versus LoBS: 1.40 ± 0.93 D, P > 0.05). This was also true for the groups wearing lenses (HiFL-L: -1.81 ± 0.73 D versus HiBS-L: -1.45 ± 0.99 D, P > 0.05; LoFL-L: -2.58 ± 0.65 D versus LoBS-L: -2.29 ± 0.50 D, P > 0.05). Nevertheless, animals under high-intensity lighting exhibited a significantly larger hyperopic shift compared with those under low-intensity lighting (HiFL versus LoFL: P development and negative lens compensation. As found in other species, effects of light intensity on refractive development were also observed in guinea pigs in both illuminants. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

The rise of the photosynthetic rate when light intensity increases is delayed in ndh gene-defective tobacco at high but not at low CO2 concentrations

Directory of Open Access Journals (Sweden)

Mercedes eMartin

2015-02-01

Full Text Available The 11 plastid ndh genes have hovered frequently on the edge of dispensability, being absent in the plastid DNA of many algae and certain higher plants. We have compared the photosynthetic activity of tobacco (Nicotiana tabacum, cv. Petit Havana with five transgenic lines (ndhF, pr-ndhF, T181D, T181A and ndhF FC and found that photosynthetic performance is impaired in transgenic ndhF-defective tobacco plants at rapidly fluctuating light intensities and higher than ambient CO2 concentrations. In contrast to wild type and ndhF FC, which reach the maximum photosynthetic rate in less than one min when light intensity suddenly increases, ndh defective plants (ndhF and T181A show up to a 5 min delay in reaching the maximum photosynthetic rate at CO2 concentrations higher than the ambient 360 ppm. Net photosynthesis was determined at different CO2 concentrations when sequences of 130, 870, 61, 870 and 130 μmol m−2 s−1 PAR sudden light changes were applied to leaves and photosynthetic efficiency and entropy production were determined as indicators of photosynthesis performance. The two ndh-defective plants, ndhF and T181A, had lower photosynthetic efficiency and higher entropy production than wt, ndhF FC and T181D tobacco plants, containing full functional ndh genes, at CO2 concentrations above 400 ppm. We propose that the Ndh complex improves cyclic electron transport by adjusting the redox level of transporters during the low light intensity stage. In ndhF-defective strains, the supply of electrons through the Ndh complex fails, transporters remain over-oxidized (specially at high CO2 concentrations and the rate of cyclic electron transport is low, impairing the ATP level required to rapidly reach high CO2 fixation rates in the following high light phase. Hence, ndh genes could be dispensable at low but not at high atmospheric concentrations of CO2.

Influence of light intensity on the photodegradation of bisphenol A polycarbonate

NARCIS (Netherlands)

Diepens, M.; Gijsman, P.

2009-01-01

The influence of light intensity on the photodegradation rate and photodegradation mechanisms of an unstabilized BPA-PC film was studied by irradiating the BPA-PC samples with a wavelength distribution comparable to terrestrial sunlight and varying irradiation intensities. The highest intensity used

Effects of light intensity on components and topographical structures of extracellular polysaccharides from the cyanobacteria Nostoc sp.

Science.gov (United States)

Ge, Hongmei; Xia, Ling; Zhou, Xuping; Zhang, Delu; Hu, Chunxiang

2014-02-01

A study on the effects of light intensity (40 and 80 μE/m(2)/sec) on the components and topographical structures of extracellular polysaccharides (EPS) was carried out in cyanobacteria Nostoc sp.. EPS yield increased with light intensity. However, light intensity did not significantly affect the EPS fractions and monosaccharide composition. Higher light intensity generally resulted in higher protein content of EPS in similar fractions. The topographical structure of EPS, investigated by atomic force microscopy, appeared as spherical lumps, chains and networks. The long chains were observed at higher light intensity. Thus, light intensity affected the yield and nature of EPS.

High intensity Discharge lighting; Alumbrado de alta intensidad de descarga

Energy Technology Data Exchange (ETDEWEB)

Mendoza E, Ernesto J [Manufacturera de Reactores, S. A., Mexico, D. F. (Mexico)

1994-12-31

This paper gets into contact with some fundamentals in the operation of high discharge intensity lamps. There are useful definitions, as well as the study of the operation of high pressure sodium lamps and of metallic additives operating at less than nominal power. [Espanol] Este trabajo pone al lector en contacto con algunos fundamentos de la operacion de las lamparas de alta intensidad de descarga (HID). Se encuentra con definiciones utiles, asi como el estudio de la operacion de las lamparas de sodio en alta presion y de aditivos metalicos operando a una potencia menor que la nominal.

High intensity Discharge lighting; Alumbrado de alta intensidad de descarga

Energy Technology Data Exchange (ETDEWEB)

Mendoza E, Ernesto J. [Manufacturera de Reactores, S. A., Mexico, D. F. (Mexico)

1993-12-31

This paper gets into contact with some fundamentals in the operation of high discharge intensity lamps. There are useful definitions, as well as the study of the operation of high pressure sodium lamps and of metallic additives operating at less than nominal power. [Espanol] Este trabajo pone al lector en contacto con algunos fundamentos de la operacion de las lamparas de alta intensidad de descarga (HID). Se encuentra con definiciones utiles, asi como el estudio de la operacion de las lamparas de sodio en alta presion y de aditivos metalicos operando a una potencia menor que la nominal.

Growth of shredders on leaf litter biofilms: the effect of light intensity

NARCIS (Netherlands)

Franken, R.J.M.; Waluto, B.; Peeters, E.T.H.M.; Gardeniers, J.J.P.; Beijer, J.A.J.; Scheffer, M.

2005-01-01

1. The effect of light intensity on the decomposition of poplar (Populus nigra) leaves and growth of the shredders, Asellus aquaticus and Gammarus pulex, was studied in a laboratory experiment. The response was studied along a gradient of six light intensities of 0, 5, 23, 54, 97 and 156 ¿mol m -2

Photosynthetic adaptation to light intensity in plants native to shaded and exposed habitats. [Rumex acetosa; Geum rivale; Lamium galeobdolon; Plantago lanceolata

Energy Technology Data Exchange (ETDEWEB)

Bjoerkman, O; Holmgren, P

1966-01-01

Photosynthetic adaptation to light intensity has been studied in clones of populations from shaded and exposed habitats of Rumex acetosa and Geum rivale. Clones of the shade species Lamium galeobdolon and the sun species Plantago lanceolata were also included for comparison. The plants were grown under controlled conditions at a high and a low light intensity. The capacity of photosynthetic carbon dioxide uptake at low as well as at saturating light intensities was determined on single attached leaves. As was previously demonstrated in Solidago virgaurea, clones of populations native to shaded and to exposed environments show differences in the photosynthetic response to light intensity during growth. The data provide evidence that populations of the same species native to habitats with contrasting light intensities differ in their photosynthetic properties in an adaptive manner in a similar mode as sun and shade species. 1 reference, 1 figure, 2 tables.

Design of Automatic Intensity Varying Smart Street Lighting System

Science.gov (United States)

Gupta, Ashutosh; Gupta, Shipra

2017-08-01

The paper is proposed with an aim of power conservation. In this era of development, it is essential to develop a streetlight that turns on and off automatically without human interference. To achieve this light sensor have been placed in each panel which turns the street light on and off automatically. For energy conservation cool-white LED’s have been used in street light panel and dimmer modules have been installed which changes the intensity of the streetlight depending on the darkness.

Unconventional Use of Intense Pulsed Light

OpenAIRE

Piccolo, D.; Di Marcantonio, D.; Crisman, G.; Cannarozzo, G.; Sannino, M.; Chiricozzi, A.; Chimenti, S.

2014-01-01

According to the literature, intense pulsed light (IPL) represents a versatile tool in the treatment of some dermatological conditions (i.e., pigmentation disorders, hair removal, and acne), due to its wide range of wavelengths. The authors herein report on 58 unconventional but effective uses of IPL in several cutaneous diseases, such as rosacea (10 cases), port-wine stain (PWS) (10 cases), disseminated porokeratosis (10 cases), pilonidal cyst (3 cases), seborrheic keratosis (10 cases), hype...

The velocity of light intensity increase modulates the photoprotective response in coastal diatoms.

Directory of Open Access Journals (Sweden)

Vasco Giovagnetti

Full Text Available In aquatic ecosystems, the superimposition of mixing events to the light diel cycle exposes phytoplankton to changes in the velocity of light intensity increase, from diurnal variations to faster mixing-related ones. This is particularly true in coastal waters, where diatoms are dominant. This study aims to investigate if coastal diatoms differently activate the photoprotective responses, xanthophyll cycle (XC and non-photochemical fluorescence quenching (NPQ, to cope with predictable light diel cycle and unpredictable mixing-related light variations. We compared the effect of two fast light intensity increases (simulating mixing events with that of a slower increase (corresponding to the light diel cycle on the modulation of XC and NPQ in the planktonic coastal diatom Pseudo-nitzschia multistriata. During each light treatment, the photon flux density (PFD progressively increased from darkness to five peaks, ranging from 100 to 650 µmol photons m-2 s-1. Our results show that the diel cycle-related PFD increase strongly activates XC through the enhancement of the carotenoid biosynthesis and induces a moderate and gradual NPQ formation over the light gradient. In contrast, during mixing-related PFD increases, XC is less activated, while higher NPQ rapidly develops at moderate PFD. We observe that together with the light intensity and its increase velocity, the saturation light for photosynthesis (Ek is a key parameter in modulating photoprotection. We propose that the capacity to adequately regulate and actuate alternative photoprotective 'safety valves' in response to changing velocity of light intensity increase further enhances the photophysiological flexibility of diatoms. This might be an evolutionary outcome of diatom adaptation to turbulent marine ecosystems characterized by unpredictable mixing-related light changes over the light diel cycle.

CW high intensity non-scaling FFAG proton drivers

OpenAIRE

Johnstone, C.; Berz, M.; Makino, K.; Snopok, P.

2012-01-01

Accelerators are playing increasingly important roles in basic science, technology, and medicine including nuclear power, industrial irradiation, material science, and neutrino production. Proton and light-ion accelerators in particular have many research, energy and medical applications, providing one of the most effective treatments for many types of cancer. Ultra high-intensity and high-energy (GeV) proton drivers are a critical technology for accelerator-driven sub-critical reactors (ADS)...

Cu ion ink for a flexible substrate and highly conductive patterning by intensive pulsed light sintering.

Science.gov (United States)

Wang, Byung-Yong; Yoo, Tae-Hee; Song, Yong-Won; Lim, Dae-Soon; Oh, Young-Jei

2013-05-22

Direct printing techniques that utilize nanoparticles to mitigate environmental pollution and reduce the processing time of the routing and formation of electrodes have received much attention lately. In particular, copper (Cu) nanoink using Cu nanoparticles offers high conductivity and can be prepared at low cost. However, it is difficult to produce homogeneous nanoparticles and ensure good dispersion within the ink. Moreover, Cu particles require a sintering process over an extended time at a high temperature due to high melting temperature of Cu. During this process, the nanoparticles oxidize quickly in air. To address these problems, the authors developed a Cu ion ink that is free of Cu particles or any other impurities. It consequently does not require separate dispersion stability. In addition, the developed ink is environmentally friendly and can be sintered even at low temperatures. The Cu ion ink was sintered on a flexible substrate using intense pulsed light (IPL), which facilitates large-area, high-speed calcination at room temperature and at atmospheric pressures. As the applied light energy increases, the Cu2O phase diminishes, leaving only the Cu phase. This is attributed to the influence of formic acid (HCOOH) on the Cu ion ink. Only the Cu phase was observed above 40 J cm(-2). The Cu-patterned film after sintering showed outstanding electrical resistivity in a range of 3.21-5.27 μΩ·cm at an IPL energy of 40-60 J cm(-2). A spiral-type micropattern with a line width of 160 μm on a PI substrate was formed without line bulges or coffee ring effects. The electrical resistivity was 5.27 μΩ·cm at an energy level of 40.6 J cm(-2).

High intensity discharge device containing oxytrihalides

Science.gov (United States)

Lapatovich, W.P.; Keeffe, W.M.; Liebermann, R.W.; Maya, J.

1987-06-09

A fill composition for a high intensity discharge device including mercury, niobium oxytrihalide, and a molecular stabilization agent is provided. The molar ratio of niobium oxytrihalide to the molecular stabilization agent in the fill is in the range of from about 5:1 to about 7.5:1. Niobium oxytrihalide is present in the fill in sufficient amount to produce, by dissociation in the discharge, atomic niobium, niobium oxide, NbO, and niobium dioxide, NbO[sub 2], with the molar ratio of niobium-containing vapor species to mercury in the fill being in the range of from about 0.01:1 to about 0.50:1; and mercury pressure of about 1 to about 50 atmospheres at lamp operating temperature. There is also provided a high intensity discharge device comprising a sealed light-transmissive arc tube; the arc tube including the above-described fill; and an energizing means for producing an electric discharge within the arc tube. 7 figs.

Metabolic acclimation to excess light intensity in Chlamydomonas reinhardtii.

Science.gov (United States)

Davis, Maria C; Fiehn, Oliver; Durnford, Dion G

2013-07-01

There are several well-described acclimation responses to excess light in green algae but the effect on metabolism has not been thoroughly investigated. This study examines the metabolic changes during photoacclimation to high-light (HL) stress in Chlamydomonas reinhardtii using nuclear magnetic resonance and mass spectrometry. Using principal component analysis, a clear metabolic response to HL intensity was observed on global metabolite pools, with major changes in the levels of amino acids and related nitrogen metabolites. Amino acid pools increased during short-term photoacclimation, but were especially prominent in HL-acclimated cultures. Unexpectedly, we observed an increase in mitochondrial metabolism through downstream photorespiratory pathways. The expression of two genes encoding key enzymes in the photorespiratory pathway, glycolate dehydrogenase and malate synthase, were highly responsive to the HL stress. We propose that this pathway contributes to metabolite pools involved in nitrogen assimilation and may play a direct role in photoacclimation. Our results suggest that primary and secondary metabolism is highly pliable and plays a critical role in coping with the energetic imbalance during HL exposure and a necessary adjustment to support an increased growth rate that is an effective energy sink for the excess reducing power generated during HL stress. © 2013 John Wiley & Sons Ltd.

Evaluate Influence to Space Lighting Intensity in Main Control Room of RSG-GAS

International Nuclear Information System (INIS)

Teguh-Sulistyo; Yuyut-S-M; Yahya; Adin S

2006-01-01

Have been done by an activity evaluate factor depreciation influence to light source in Main Control Room (RKU). This Factor Depreciation is resulted from by defilement of effect of dirt, duration of light source utilized, way of installation, and others. Method used by perceives directly at light source, determining measurement dot in space RKU, measurement by using meter lux equipment and group storey; level depreciation of light source become light depreciation, and heavy. Than measurement result that lighting intensity in space RKU experience of decrease of equal to 1.5 %. After by stage; steps overcome the factor depreciation, result of measurement repeat obtained by decrease of equal to 0.87 %. Thereby the lighting intensity in space RKU becomes better. (author)

The role of lasers and intense pulsed light technology in dermatology

Science.gov (United States)

Husain, Zain; Alster, Tina S

2016-01-01

The role of light-based technologies in dermatology has expanded dramatically in recent years. Lasers and intense pulsed light have been used to safely and effectively treat a diverse array of cutaneous conditions, including vascular and pigmented lesions, tattoos, scars, and undesired hair, while also providing extensive therapeutic options for cosmetic rejuvenation and other dermatologic conditions. Dermatologic laser procedures are becoming increasingly popular worldwide, and demand for them has fueled new innovations and clinical applications. These systems continue to evolve and provide enhanced therapeutic outcomes with improved safety profiles. This review highlights the important roles and varied clinical applications that lasers and intense pulsed light play in the dermatologic practice. PMID:26893574

Efficacy of intense pulse light therapy and tripple combination cream versus intense pulse light therapy and tripple combination cream alone in epidermal melasma treatment

International Nuclear Information System (INIS)

Shakeeb, N.; Noor, S.M.; Paracha, M.M.; Ullah, G.

2018-01-01

Objective:To compare the efficacy of intense pulse light therapy (IPL) and triple combination cream (TCC) versus intense pulse light therapy and triple combination cream alone in epidermal melasma treatment, downgrading MASI score to more than 10. Study Design:Randomized controlled trial. Place and Duration of Study:Dermatology Department, Lady Reading Hospital, Peshawar, from August 2014 to January 2015. Methodology:Patients of 18-45 years were included in the study with Fitzpatrick skin type II-V. Sample of 96 patients was divided in to three groups of 32 each, through consecutive (non-probability) sampling method. Detailed history was taken, Woods Lamp Examination done, and melasma area and severity index (MASI) score was calculated. TCC had to be applied daily at night for two months by group A patients while group B was consigned for IPL therapy fortnightly, and those in group C were given both for two months. Efficacy was compared by recalculating MASI score at treatment end as well as at follow-up after 4 weeks, using Chi-square test with significance at p < 0.05. Results:Male and female patients were 10 (31.2%) and 22 (68.8%) in group A, 7 (21.9%) and 25 (78.1%) in group B, while in group C were 12 (37.5%) and 20 (62.5%). The average age was 28.70 +8.70 years. MASI score reduction was achieved in 22 (68.8%) patients in group A; whereas, in 20 (62.5%) and 30(93.8%) patients in group B and C, respectively. Efficacy-wise distribution was significant (p=0.009). Conclusion:Intense pulse light therapy and triple combination cream are more efficacious in epidermal melasma treatment than intense pulse light therapy and triple combination cream alone. (author)

Light-intensity physical activity is associated with insulin resistance in elderly Japanese women independent of moderate-to vigorous-intensity physical activity.

Science.gov (United States)

Gando, Yuko; Murakami, Haruka; Kawakami, Ryoko; Tanaka, Noriko; Sanada, Kiyoshi; Tabata, Izumi; Higuchi, Mitsuru; Miyachi, Motohiko

2014-02-01

It is unclear whether light physical activity is beneficially associated with insulin resistance, similar to moderate and/or vigorous physical activity. This cross-sectional study was performed to determine the relationship between the amount of light physical activity, as determined with a triaxial accelerometer, and insulin resistance. A total of 807 healthy men and women participated in this study. Physical activity was measured using a triaxial accelerometer worn for 28 days and summarized as light intensity (1.1-2.9 METs) or moderate to vigorous intensity (≥ 3.0 METs). Insulin resistance was evaluated by HOMA_R (FPG [mg/dL] × IRI [μU/mL]/405). The daily time spent in light physical activity was inversely associated with HOMA_R (r = -0.173, P physical activity and HOMA_R remained statistically significant (β = -0.119, P physical activity remained significantly associated with HOMA_R following further adjustment for moderate to vigorous intensity activity (β = -0.125, P physical activity was modeled as quartiles, especially in elderly women. These cross-sectional data suggest that light-intensity physical activity is beneficially associated with insulin resistance in elderly Japanese women.

Effects of temperature and light intensity on the uptake and assimilation of 15N-labeled ammonium and nitrate in Indica and Japonica rice plants

International Nuclear Information System (INIS)

Ta, T.C.; Ohira, Koji

1982-01-01

The effects of various environmental condition such as temperature and light intensity on the uptake and assimilation of ammonium and nitrate in 4-week-old Indica and Japonica rice plants were studied using the 15 N tracer technique. Both temperature and light intensity profoundly affected the uptake and assimilation of ammonium and nitrate, and the effects were more apparent in the utilization of nitrate by both Indica and Japonica rice plants. The uptake as well as assimilation of the two forms of nitrogen were greatly inhibited at low temperature and low light intensity. On the other hand, although no significant difference in the effects of environmental conditions on the utilization of ammonium was observed between the Indica and Japonica rice plants, the former were more sensitive than the latter in the utilization of nitrate. At high temperature and high light intensity, the Indica rice plants absorbed, reduced, and assimilated nitrate more effectively than the Japonica, and this effect disappeared when the temperature or light intensity was reduced. (author)

Highly Efficient Light-Driven TiO2-Au Janus Micromotors.

Science.gov (United States)

Dong, Renfeng; Zhang, Qilu; Gao, Wei; Pei, Allen; Ren, Biye

2016-01-26

A highly efficient light-driven photocatalytic TiO2-Au Janus micromotor with wireless steering and velocity control is described. Unlike chemically propelled micromotors which commonly require the addition of surfactants or toxic chemical fuels, the fuel-free Janus micromotor (diameter ∼1.0 μm) can be powered in pure water under an extremely low ultraviolet light intensity (2.5 × 10(-3) W/cm(2)), and with 40 × 10(-3) W/cm(2), they can reach a high speed of 25 body length/s, which is comparable to common Pt-based chemically induced self-electrophoretic Janus micromotors. The photocatalytic propulsion can be switched on and off by incident light modulation. In addition, the speed of the photocatalytic TiO2-Au Janus micromotor can be accelerated by increasing the light intensity or by adding low concentrations of chemical fuel H2O2 (i.e., 0.1%). The attractive fuel-free propulsion performance, fast movement triggering response, low light energy requirement, and precise motion control of the TiO2-Au Janus photocatalytic micromotor hold considerable promise for diverse practical applications.

Light intensity as major factor to maximize biomass and lipid productivity of Ettlia sp. in CO2-controlled photoautotrophic chemostat.

Science.gov (United States)

Seo, Seong-Hyun; Ha, Ji-San; Yoo, Chan; Srivastava, Ankita; Ahn, Chi-Yong; Cho, Dae-Hyun; La, Hyun-Joon; Han, Myung-Soo; Oh, Hee-Mock

2017-11-01

The optimal culture conditions are critical factors for high microalgal biomass and lipid productivity. To optimize the photoautotrophic culture conditions, combination of the pH (regulated by CO 2 supply), dilution rate, and light intensity was systematically investigated for Ettlia sp. YC001 cultivation in a chemostat during 143days. The biomass productivity increased with the increase in dilution rate and light intensity, but decreased with increasing pH. The average lipid content was 19.8% and statistically non-variable among the tested conditions. The highest biomass and lipid productivities were 1.48gL -1 d -1 and 291.4mgL -1 d -1 with a pH of 6.5, dilution rate of 0.78d -1 , and light intensity of 1500μmolphotonsm -2 s -1 . With a sufficient supply of CO 2 and nutrients, the light intensity was the main determinant of the photosynthetic rate. Therefore, the surface-to-volume ratio of a photobioreactor should enable efficient light distribution to enhance microalgal growth. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fluorescent and high intensity discharge lamp use in chambers and greenhouses

Science.gov (United States)

Langhans, Robert W.

1994-01-01

Fluorescent and High Intensity Discharge lamps have opened up great opportunities for researchers to study plant growth under controlled environment conditions and for commercial growers to increase plant production during low/light periods. Specific technical qualities of fluorescent and HID lamps have been critically reviewed. I will direct my remarks to fluorescent and high intensity discharge (HID) lamps in growth chambers, growth rooms, and greenhouses. I will discuss the advantages and disadvantages of using each lamp in growth chambers, growth rooms and greenhouses.

Nutrient concentrations in a Littorella uniflora community at higher CO₂ concentrations and reduced light intensities

DEFF Research Database (Denmark)

Andersen, T.; Pedersen, O.; Andersen, F. Ø.

2005-01-01

laboratory experiments with isoetid vegetation (Littorella uniflora) where water column CO2 and light could be manipulated in order to test whether (i) light and CO2 availability affect nutrient concentrations in isoetid vegetation, and (ii) if changes in light and CO2 climate affect fluxes of inorganic...... nitrogen (N) and phosphorus (P) from sediment to water column, which potentially could result in increased growth of epiphytic algae. 3. The results showed that the standing stocks of phosphorus and nitrogen in the L. uniflora vegetation were significantly influenced by CO2 concentration and light...... intensity. Both standing stocks of P and N were significantly higher in the mesocosm treatments with high CO2 concentration than in those at low CO2 concentration. Similarly, standing stocks of P and N enhanced with increasing light intensity. 4. Measurements of nutrient fluxes both in the field...

AFSC/RACE/GAP/Kotwicki: Relative light intensity collected during bottom trawl surveys

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Assessing the effect of light intensity and light penetration on the distributionand behavior of walleye pollock (Gadus chalcogrammus) in the eastern Bering Sea and...

Monitoring of transient cavitation induced by ultrasound and intense pulsed light in presence of gold nanoparticles.

Science.gov (United States)

Sazgarnia, Ameneh; Shanei, Ahmad; Shanei, Mohammad Mahdi

2014-01-01

One of the most important challenges in medical treatment is invention of a minimally invasive approach in order to induce lethal damages to cancer cells. Application of high intensity focused ultrasound can be beneficial to achieve this goal via the cavitation process. Existence of the particles and vapor in a liquid decreases the ultrasonic intensity threshold required for cavitation onset. In this study, synergism of intense pulsed light (IPL) and gold nanoparticles (GNPs) has been investigated as a means of providing nucleation sites for acoustic cavitation. Several approaches have been reported with the aim of cavitation monitoring. We conducted the experiments on the basis of sonochemiluminescence (SCL) and chemical dosimetric methods. The acoustic cavitation activity was investigated by determining the integrated SCL signal acquired over polyacrylamide gel phantoms containing luminol in the presence and absence of GNPs in the wavelength range of 400-500 nm using a spectrometer equipped with cooled charged coupled devices (CCD) during irradiation by different intensities of 1 MHz ultrasound and IPL pulses. In order to confirm these results, the terephthalic acid chemical dosimeter was utilized as well. The SCL signal recorded in the gel phantoms containing GNPs at different intensities of ultrasound in the presence of intense pulsed light was higher than the gel phantoms without GNPs. These results have been confirmed by the obtained data from the chemical dosimetry method. Acoustic cavitation in the presence of GNPs and intense pulsed light has been suggested as a new approach designed for decreasing threshold intensity of acoustic cavitation and improving targeted therapeutic effects. Copyright © 2013 Elsevier B.V. All rights reserved.

Light illumination intensity dependence of photovoltaic parameter in polymer solar cells with ammonium heptamolybdate as hole extraction layer.

Science.gov (United States)

Liu, Zhiyong; Niu, Shengli; Wang, Ning

2018-01-01

A low-temperature, solution-processed molybdenum oxide (MoO X ) layer and a facile method for polymer solar cells (PSCs) is developed. The PSCs based on a MoO X layer as the hole extraction layer (HEL) is a significant advance for achieving higher photovoltaic performance, especially under weaker light illumination intensity. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) measurements show that the (NH 4 ) 6 Mo 7 O 24 molecule decomposes and forms the molybdenum oxide (MoO X ) molecule when undergoing thermal annealing treatment. In this study, PSCs with the MoO X layer as the HEL exhibited better photovoltaic performance, especially under weak light illumination intensity (from 100 to 10mWcm -2 ) compared to poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS)-based PSCs. Analysis of the current density-voltage (J-V) characteristics at various light intensities provides information on the different recombination mechanisms in the PSCs with a MoO X and PEDOT:PSS layer as the HEL. That the slopes of the open-circuit voltage (V OC ) versus light illumination intensity plots are close to 1 unity (kT/q) reveals that bimolecular recombination is the dominant and weaker monomolecular recombination mechanism in open-circuit conditions. That the slopes of the short-circuit current density (J SC ) versus light illumination intensity plots are close to 1 reveals that the effective charge carrier transport and collection mechanism of the MoO X /indium tin oxide (ITO) anode is the weaker bimolecular recombination in short-circuit conditions. Our results indicate that MoO X is an alternative candidate for high-performance PSCs, especially under weak light illumination intensity. Copyright © 2017 Elsevier Inc. All rights reserved.

Characterization of highly scattering media by measurement of diffusely backscattered polarized light

Science.gov (United States)

Hielscher, Andreas H.; Mourant, Judith R.; Bigio, Irving J.

2000-01-01

An apparatus and method for recording spatially dependent intensity patterns of polarized light that is diffusely backscattered from highly scattering media are described. These intensity patterns can be used to differentiate different turbid media, such as polystyrene-sphere and biological-cell suspensions. Polarized light from a He-Ne laser (.lambda.=543 nm) is focused onto the surface of the scattering medium, and a surface area of approximately 4.times.4 cm centered on the light input point is imaged through polarization analysis optics onto a CCD camera. A variety of intensity patterns may be observed by varying the polarization state of the incident laser light and changing the analyzer configuration to detect different polarization components of the backscattered light. Experimental results for polystyrene-sphere and Intralipid suspensions demonstrate that the radial and azimuthal variations of the observed pattern depend on the concentration, size, and anisotropy factor, g, of the particles constituting the scattering medium. Measurements performed on biological cell suspensions show that intensity patterns can be used to differentiate between suspensions of cancerous and non-cancerous cells. Introduction of the Mueller-matrix for diffusely backscattered light, permits the selection of a subset of measurements which comprehensively describes the optical properties of backscattering media.

Measurement-device-independent quantum key distribution with correlated source-light-intensity errors

Science.gov (United States)

Jiang, Cong; Yu, Zong-Wen; Wang, Xiang-Bin

2018-04-01

We present an analysis for measurement-device-independent quantum key distribution with correlated source-light-intensity errors. Numerical results show that the results here can greatly improve the key rate especially with large intensity fluctuations and channel attenuation compared with prior results if the intensity fluctuations of different sources are correlated.

Effect of light intensity and irradiation time on the polymerization process of a dental composite resin

Directory of Open Access Journals (Sweden)

Discacciati José Augusto César

2004-01-01

Full Text Available Polymerization shrinkage is a critical factor affecting the longevity and acceptability of dental composite resins. The aim of this work was to evaluate the effect of light intensity and irradiation time on the polymerization process of a photo cured dental composite resin by measuring the Vickers hardness number (VHN and the volumetric polymerization shrinkage. Samples were prepared using a dental manual light-curing unit. The samples were submitted to irradiation times of 5, 10, 20 and 40 s, using 200 and 400 mW.cm-2 light intensities. Vickers hardness number was obtained at four different moments after photoactivation (immediate, 1 h, 24 h and 168 h. After this, volumetric polymerization shrinkage values were obtained through a specific density method. The values were analyzed by ANOVA and Duncan's (p = 0.05. Results showed increase in hardness values from the immediate reading to 1 h and 24 h readings. After 24 h no changes were observed regardless the light intensities or activation times. The hardness values were always smaller for the 200 mW.cm-2 light intensity, except for the 40 s irradiation time. No significant differences were detected in volumetric polymerization shrinkage considering the light intensity (p = 0.539 and the activation time (p = 0.637 factors. In conclusion the polymerization of the material does not terminate immediately after photoactivation and the increase of irradiation time can compensate a lower light intensity. Different combinations between light intensity and irradiation time, i.e., different amounts of energy given to the system, have not affected the polymerization shrinkage.

Predawn and high intensity application of supplemental blue light decreases the quantum yield of PSII and enhances the amount of phenolic acids, flavonoids, and pigments in Lactuca sativa.

Directory of Open Access Journals (Sweden)

Theoharis eOuzounis

2015-02-01

Full Text Available To evaluate the effect of blue light intensity and timing, two cultivars of lettuce [Lactuca sativa cv. ’Batavia’ (green and cv. ‘Lollo Rossa’ (red] were grown in a greenhouse compartment in late winter under natural light and supplemental high pressure sodium (SON-T lamps yielding 90 (±10 µmol m-2 s-1 for up to 20 hr, but never between 17:00 and 21:00. The temperature in the greenhouse compartments was 22/11°C day/night, respectively. The five light-emitting diode (LED light treatments were Control (no blue addition, 1B 06-08 (Blue light at 45 µmol m-2 s-1 from 06:00 to 08:00, 1B 21-08 (Blue light at 45 µmol m-2 s-1 from 21:00 to 08:00, 2B 17-19 (Blue at 80 µmol m-2 s-1 from 17:00 to 19:00, and (1B 17-19 Blue at 45 µmol m-2 s-1from 17:00 to 19:00. Total fresh and dry weight was not affected with additional blue light; however, plants treated with additional blue light were more compact. The stomatal conductance in the green lettuce cultivar was higher for all treatments with blue light compared to the Control. Photosynthetic yields measured with chlorophyll fluorescence showed different response between the cultivars; in red lettuce, the quantum yield of PSII decreased and the yield of non-photochemical quenching increased with increasing blue light, whereas in green lettuce no difference was observed. Quantification of secondary metabolites showed that all four treatments with additional blue light had higher amount of pigments, phenolic acids, and flavonoids compared to the Control. The effect was more prominent in red lettuce, highlighting that the results vary among treatments and compounds. Our results indicate that not only high light level triggers photoprotective heat dissipation in the plant, but also the specific spectral composition of the light itself at low intensities. However, these plant responses to light are cultivar dependent.

Predawn and high intensity application of supplemental blue light decreases the quantum yield of PSII and enhances the amount of phenolic acids, flavonoids, and pigments in Lactuca sativa.

Science.gov (United States)

Ouzounis, Theoharis; Razi Parjikolaei, Behnaz; Fretté, Xavier; Rosenqvist, Eva; Ottosen, Carl-Otto

2015-01-01

To evaluate the effect of blue light intensity and timing, two cultivars of lettuce [Lactuca sativa cv. "Batavia" (green) and cv. "Lollo Rossa" (red)] were grown in a greenhouse compartment in late winter under natural light and supplemental high pressure sodium (SON-T) lamps yielding 90 (±10) μmol m(-2) s(-1) for up to 20 h, but never between 17:00 and 21:00. The temperature in the greenhouse compartments was 22/11°C day/night, respectively. The five light-emitting diode (LED) light treatments were Control (no blue addition), 1B 06-08 (Blue light at 45 μmol m(-2) s(-1) from 06:00 to 08:00), 1B 21-08 (Blue light at 45 μmol m(-2) s(-1) from 21:00 to 08:00), 2B 17-19 (Blue at 80 μmol m(-2) s(-1) from 17:00 to 19:00), and 1B 17-19 (Blue at 45 μmol m(-2) s(-1) from 17:00 to 19:00). Total fresh and dry weight was not affected with additional blue light; however, plants treated with additional blue light were more compact. The stomatal conductance in the green lettuce cultivar was higher for all treatments with blue light compared to the Control. Photosynthetic yields measured with chlorophyll fluorescence showed different response between the cultivars; in red lettuce, the quantum yield of PSII decreased and the yield of non-photochemical quenching increased with increasing blue light, whereas in green lettuce no difference was observed. Quantification of secondary metabolites showed that all four treatments with additional blue light had higher amount of pigments, phenolic acids, and flavonoids compared to the Control. The effect was more prominent in red lettuce, highlighting that the results vary among treatments and compounds. Our results indicate that not only high light level triggers photoprotective heat dissipation in the plant, but also the specific spectral composition of the light itself at low intensities. However, these plant responses to light are cultivar dependent.

Predawn and high intensity application of supplemental blue light decreases the quantum yield of PSII and enhances the amount of phenolic acids, flavonoids, and pigments in Lactuca sativa

Science.gov (United States)

Ouzounis, Theoharis; Razi Parjikolaei, Behnaz; Fretté, Xavier; Rosenqvist, Eva; Ottosen, Carl-Otto

2015-01-01

To evaluate the effect of blue light intensity and timing, two cultivars of lettuce [Lactuca sativa cv. “Batavia” (green) and cv. “Lollo Rossa” (red)] were grown in a greenhouse compartment in late winter under natural light and supplemental high pressure sodium (SON-T) lamps yielding 90 (±10) μmol m−2 s−1 for up to 20 h, but never between 17:00 and 21:00. The temperature in the greenhouse compartments was 22/11°C day/night, respectively. The five light-emitting diode (LED) light treatments were Control (no blue addition), 1B 06-08 (Blue light at 45 μmol m−2 s−1 from 06:00 to 08:00), 1B 21-08 (Blue light at 45 μmol m−2 s−1 from 21:00 to 08:00), 2B 17-19 (Blue at 80 μmol m−2 s−1 from 17:00 to 19:00), and 1B 17-19 (Blue at 45 μmol m−2 s−1 from 17:00 to 19:00). Total fresh and dry weight was not affected with additional blue light; however, plants treated with additional blue light were more compact. The stomatal conductance in the green lettuce cultivar was higher for all treatments with blue light compared to the Control. Photosynthetic yields measured with chlorophyll fluorescence showed different response between the cultivars; in red lettuce, the quantum yield of PSII decreased and the yield of non-photochemical quenching increased with increasing blue light, whereas in green lettuce no difference was observed. Quantification of secondary metabolites showed that all four treatments with additional blue light had higher amount of pigments, phenolic acids, and flavonoids compared to the Control. The effect was more prominent in red lettuce, highlighting that the results vary among treatments and compounds. Our results indicate that not only high light level triggers photoprotective heat dissipation in the plant, but also the specific spectral composition of the light itself at low intensities. However, these plant responses to light are cultivar dependent. PMID:25767473

Light Penetration and Light-Intensity in Sandy Marine-Sediments Measured with Irradiance and Scalar Irradiance Fiberoptic Microprobes Rid A-1977-2009

DEFF Research Database (Denmark)

KUHL, M.; LASSEN, C.; JØRGENSEN, BB

1994-01-01

Fiber-optic microprobes for determining irradiance and scalar irradiance were used for light measurements in sandy sediments of different particle size. Intense scattering caused a maximum integral light intensity [photon scalar irradiance, E0(400 to 700 rim) and E0(700 to 880 nm)] at the sediment...... diffuse. Our results demonstrate the importance of measuring scalar irradiance when the role of light in photobiological processes in sediments, e.g. microbenthic photosynthesis, is investigated....... surface ranging from 180 % of incident collimated light in the coarsest sediment (250 to 500 mum grain size) up to 280 % in the finest sediment ( 1 mm in the coarsest sediments. Below 1 mm, light was attenuated exponentially with depth in all sediments. Light attenuation coefficients decreased...

Effects of light intensity and quality on phycobiliprotein accumulation in the cyanobacterium Nostoc sphaeroides Kützing.

Science.gov (United States)

Ma, Rui; Lu, Fan; Bi, Yonghong; Hu, Zhengyu

2015-08-01

To assess the effects of light intensity and quality on the growth and phycobiliproteins (PBP) accumulation in Nostoc sphaeroides Kützing (N. sphaeroides). Dry weights, dry matter, protein, chlorophyll and PBP contents were higher under 90 μmol m(-2) s(-1) than under other intensities (both higher and lower). Phycocyanin and allophycocyanin increased with light intensity while phycoerythrin decreased. Fresh weights, protein and PBP contents increased at the highest rates under blue light. Red light resulted in higher values of dry matter, phycocyanin and chlorophyll a. White light at 90 μmol m(-2) s(-1) or blue light 30 μmol m(-2) s(-1) were optimal for the growth and phycobiliprotein accumulation in N. sphaeroides.

Exotic behavior of molecules in intense laser light fields. New research directions

Energy Technology Data Exchange (ETDEWEB)

Yamanouchi, Kaoru [Tokyo Univ., Department of Chemistry, Tokyo (Japan)

2002-08-01

The recent investigation of the dynamical behavior of molecules and clusters in intense laser fields has afforded us invaluable opportunities to understand fundamentals of the interaction between molecular species and light fields as well as to manipulate molecules and their dynamical pathways by taking advantage of characteristics of coherent ultrashort laser light fields. In the present report, new directions of this rapidly growing interdisciplinary research fields called molecular science in intense laser fields are discussed by referring to our recent studies. (author)

Photodynamic Therapy Activated by Intense Pulsed Light in the Treatment of Nonmelanoma Skin Cancer

Directory of Open Access Journals (Sweden)

Domenico Piccolo

2018-02-01

Full Text Available Photodynamic therapy (PDT with topical 5-aminolevulinic acid (ALA or methyl aminolevulinate (MAL has proven to be a highly effective conservative method for the treatment of actinic keratosis (AK, Bowen’s disease (BD, and superficial basal cell carcinoma (sBCC. PDT is traditionally performed in association with broad-spectrum continuous-wave light sources, such as red or blue light. Recently, intense pulsed light (IPL devices have been investigated as an alternative light source for PDT in the treatment of nonmelanoma skin cancers (NMSC. We herein report our observational findings in a cohort of patients with a diagnosis of AK, sBCC, and BD that is treated with MAL-PDT using IPL, as well as we review published data on the use of IPL-PDT in NMSC.

Effects of forward and backward transitions in light intensities in tau-illuminance curves of the rat motor activity rhythm under constant dim light.

Science.gov (United States)

Cambras, Trinitat; Díez-Noguera, Antoni

2012-07-01

Circadian rhythms are strongly influenced by light intensity, the effects of which may persist beyond the duration of light exposure (aftereffects). Here, the authors constructed period-illuminance curves for the motor activity circadian rhythm of male and female rats by recording the effects of a series of small upward and downward steps in light intensity (illuminance ranging between .01 lux of dim red light and 1 lux of white light) on their activity. In all cases, stepwise changes were made in five logarithmic steps (irradiance: dim red light: .692 µW/cm(2) and white light: .006, .016, .044, .12, and .315 µW/cm(2), corresponding, respectively, to .02, .05, .14, .13, and 1 lux measured at cage level), with changes in intensity every 2 wks. One group of rats (DLD) started in dim red light, moved up to 1 lux white light, and then back down to the original light intensity. Another group (LDL) started at 1 lux, moved down to .01 lux, and then back up to the original intensity. Motor activity data were recorded throughout the experiment and tau values, the percentage of variance explained by the rhythm, and the mean motor activity for each stage and group were calculated. The results show differences in the dynamics of tau values between the DLD and LDL groups and between males and females. In the LDL group, the tau values of both males and females were dependent on light intensity, and were similar for the forward and backward transitions. In other words, no aftereffects were found, and no differences were detected between males and females. In the DLD group, however, differences were found between males and females. Males had a tau value of 24 h 20 min under dim red light, 25 h 40 min under 1 lux, and 24 h 50 min on return to dim red light. It is noticeable that the tau values of the backward branch of the illuminance curve contradicted classical predictions, since at .38 and .14 lux the tau values were shorter than those found under the same intensities after

Intense light-ion beams provide a robust, common-driver path toward ignition, gain, and commercial fusion energy

International Nuclear Information System (INIS)

Ramirez, J.J.; Cook, D.L.

1993-01-01

Intense light-ion beams are being developed for investigations of inertial confinement fusion (ICF). This effort has concentrated on developing the Particle Beam Fusion Accelerator II (PBFA II) at Sandia as a driver for ICF target experiments, on design concepts for a high-yield, high-gain Laboratory Microfusion Facility (LMF), and on a comprehensive system study of a light-ion beam-driven commercial fusion reactor (LIBRA). Reports are given on the status of design concepts and research in these areas. (author)

Efficient coupling of high intensity short laser pulses into snow clusters

Science.gov (United States)

Palchan, T.; Pecker, S.; Henis, Z.; Eisenmann, S.; Zigler, A.

2007-01-01

Measurements of energy absorption of high intensity laser pulses in snow clusters are reported. Targets consisting of sapphire coated with snow nanoparticles were found to absorb more than 95% of the incident light compared to 50% absorption in flat sapphire targets.

Proteomic study related to vascular connections in watermelon scions grafted onto bottle-gourd rootstock under different light intensities.

Directory of Open Access Journals (Sweden)

Sowbiya Muneer

Full Text Available Although grafting is broadly used in the production of crops, no information is available about the proteins involved in vascular connections between rootstock and scion. Similarly, proteome changes under the light intensities widely used for grafted seedlings are of practical use. The objective of this study was to determine the proteome of vascular connections using watermelon (Citrullus vulgaris Schrad. 'Sambok Honey' and 'Speed' as the scion and bottle gourd (Lagenaria siceraria Stanld. 'RS Dongjanggun' as the rootstock grown under different light intensities (25, 50, 75 and 100 μmol m-2 s-1. Our proteomic analysis revealed 24 and 27 differentially expressed proteins in 'Sambok Honey' and 'Speed', respectively, under different light intensities. The identified proteins were largely involved in ion binding, amino acid metabolism, transcriptional regulation and defense response. The enhancement of ion-binding, transcriptional regulation, amino acid metabolism, and defense response proteins suggests a strengthening of the connection between the rootstock and scion under high light intensity. Indeed, the accumulation of key enzymes in the biological processes described above appears to play an important role in the vascular connections of grafted seedlings. Moreover, it appears that 100 μmol m-2 s-1 results in better protein expression responses in grafted seedlings.

General theory of intensity correlation on light scattering

International Nuclear Information System (INIS)

Villaeys, A.A.

1978-01-01

A general theory for spatio-temporal intensity correlations measurements for a scattered beam is developed. A completely quantum mechanical description for both excitation and detection set up is used. This description is essentially valid for weak incident light beams and single photon absorption processes. From a unified point of view both, stationary as well as, time resolved experiments are described. The interest for such experiments in the study of processes like resonance raman scattering and resonance fluorescence is emphasized. Also an observable coherent contribution associated to different final levels of the target-atoms or molecules is obtained a result which cannot be reached by intensity measurements

Numerical study of the light output intensity of the bilayer organic light-emitting diodes

Science.gov (United States)

Lu, Feiping

2017-02-01

The structure of organic light-emitting diodes (OLEDs) is one of most important issues that influence the light output intensity (LOI) of OLEDs. In this paper, based on a simple but accurate optical model, the influences of hole and electron transport layer thickness on the LOI of bilayer OLEDs, which with N,N0- bis(naphthalen-1-yl)-N,N0- bis(phenyl)- benzidine (NPB) or N,N'- diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4-diamine (TPD) as hole transport layer, with tris(8-hydroxyquinoline) aluminum (Alq3) as electron transport and light emitting layers, were investigated. The laws of LOI for OLEDs under different organic layer thickness values were obtained. The results show that the LOI of devices varies in accordance with damped cosine or sine function as the increasing of organic layer thickness, and the results show that the bilayer OLEDs with the structure of Glass/ITO/NPB (55 nm)/Alq3 (75 nm)/Al and Glass/ITO/TPB (60 nm)/Alq3 (75 nm)/Al have most largest LOI. When the thickness of Alq3 is less than 105 nm, the OLEDs with TPD as hole transport layer have larger LOI than that with NPB as hole transport layer. The results obtained in this paper can present an in-depth understanding of the working mechanism of OLEDs and help ones fabricate high efficiency OLEDs.

Development of a digital astronomical intensity interferometer: laboratory results with thermal light

Science.gov (United States)

Matthews, Nolan; Kieda, David; LeBohec, Stephan

2018-06-01

We present measurements of the second-order spatial coherence function of thermal light sources using Hanbury-Brown and Twiss interferometry with a digital correlator. We demonstrate that intensity fluctuations between orthogonal polarizations, or at detector separations greater than the spatial coherence length of the source, are uncorrelated but can be used to reduce systematic noise. The work performed here can readily be applied to existing and future Imaging Air-Cherenkov Telescopes used as star light collectors for stellar intensity interferometry to measure spatial properties of astronomical objects.

THE EFFECT OF MAGNETIC FIELD ON THE EFFICIENCY OF A SILICON SOLAR CELL UNDER AN INTENSE LIGHT CONCENTRATION

Directory of Open Access Journals (Sweden)

Zoungrana Martial

2017-06-01

Full Text Available This work put in evidence, magnetic field effect the electrical parameters of a silicon solar cell illuminated by an intense light concentration: external load electric power, conversion efficiency, fill factor, external optimal charge load. Due to the high photogeneration of carrier in intense light illumination mode, in addition of magnetic field, we took into account the carrier gradient electric field in the base of the solar cell. Taking into account this electric field and the applied magnetic field in our model led to new analytical expressions of the continuity equation, the photocurrent and the photovoltage.

Differential response of Scots pine seedlings to variable intensity and ratio of red and far-red light.

Science.gov (United States)

Razzak, Abdur; Ranade, Sonali Sachin; Strand, Åsa; García-Gil, M R

2017-08-01

We investigated the response to increasing intensity of red (R) and far-R (FR) light and to a decrease in R:FR ratio in Pinus sylvestris L. (Scots pine) seedling. The results showed that FR high-irradiance response for hypocotyl elongation may be present in Scots pine and that this response is enhanced by increasing light intensity. However, both hypocotyl inhibition and pigment accumulation were more strongly affected by the R light compared with FR light. This is in contrast to previous reports in Arabidopsis thaliana (L.) Heynh. In the angiosperm, A. thaliana R light shows an overall milder effect on inhibition of hypocotyl elongation and on pigment biosynthesis compared with FR suggesting conifers and angiosperms respond very differently to the different light regimes. Scots pine shade avoidance syndrome with longer hypocotyls, shorter cotyledons and lower chlorophyll content in response to shade conditions resembles the response observed in A. thaliana. However, anthocyanin accumulation increased with shade in Scots pine, which again differs from what is known in angiosperms. Overall, the response of seedling development and physiology to R and FR light in Scots pine indicates that the regulatory mechanism for light response may differ between gymnosperms and angiosperms. © 2017 John Wiley & Sons Ltd.

Studying Intense Pulsed Light Method Along With Corticosteroid Injection in Treating Keloid Scars

OpenAIRE

Shamsi Meymandi, Simin; Rezazadeh, Azadeh; Ekhlasi, Ali

2014-01-01

Background: Results of various studies suggest that the hypertrophic and keloid scars are highly prevalent in the general population and are irritating both physically and mentally. Objective: Considering the variety of existing therapies, intense pulsed light (IPL) method along with corticosteroid injection was evaluated in treating these scars. Materials and Methods: 86 subjects were included in this clinical trial. Eight sessions of therapeutic intervention were done with IPL along with co...

Effects of light intensity on cylindrospermopsin production in the ...

African Journals Online (AJOL)

The role of light intensity on growth and the production of the hepatotoxin cylindrospermopsin (CYN) in the cyanobacterial harmful algal bloom species Cylindrospermopsis raciborskii was investigated using cultured isolates grown in N-free media under a series of neutral density screens. Maximum growth as indicated by ...

Inhibition of enteric pathogens using integrated high intensity 405 nm LED on the surface of almonds

Science.gov (United States)

The disinfecting properties of 405 nm light were investigated against Escherichia coli O157:H7, Salmonella, and their non-pathogenic surrogates inoculated onto the surface of almonds. High intensity monochromatic light was generated from an array of narrow-band 405 nm light emitting diodes (LED). Al...

High-Intensity High-order Harmonics Generated from Low-Density Plasma

International Nuclear Information System (INIS)

Ozaki, T.; Bom, L. B. Elouga; Abdul-Hadi, J.; Ganeev, R. A.; Haessler, S.; Salieres, P.

2009-01-01

We study the generation of high-order harmonics from lowly ionized plasma, using the 10 TW, 10 Hz laser of the Advanced Laser Light Source (ALLS). We perform detailed studies on the enhancement of a single order of the high-order harmonic spectrum generated in plasma using the fundamental and second harmonic of the ALLS beam line. We observe quasi-monochromatic harmonics for various targets, including Mn, Cr, Sn, and In. We identify most of the ionic/neutral transitions responsible for the enhancement, which all have strong oscillator strengths. We demonstrate intensity enhancements of the 13th, 17th, 29th, and 33rd harmonics from these targets using the 800 nm pump laser and varying its chirp. We also characterized the attosecond nature of such plasma harmonics, measuring attosecond pulse trains with 360 as duration for chromium plasma, using the technique of ''Reconstruction of Attosecond Beating by Interference of Two-photon Transitions''(RABBIT). These results show that plasma harmonics are intense source of ultrashort coherent soft x-rays.

Polydisperse-particle-size-distribution function determined from intensity profile of angularly scattered light

International Nuclear Information System (INIS)

Alger, T.W.

1979-01-01

A new method for determining the particle-size-distribution function of a polydispersion of spherical particles is presented. The inversion technique for the particle-size-distribution function is based upon matching the measured intensity profile of angularly scattered light with a summation of the intensity contributions of a series of appropriately spaced, narrowband, size-distribution functions. A numerical optimization technique is used to determine the strengths of the individual bands that yield the best agreement with the measured scattered-light-intensity profile. Because Mie theory is used, the method is applicable to spherical particles of all sizes. Several numerical examples demonstrate the application of this inversion method

Effect of temperature, light intensity and growth regulators on ...

African Journals Online (AJOL)

Ansellia africana (Orchidaceae) is an important endangered medicinal plant species of South Africa which has been heavily exploited in recent years. Experiments were conducted in growth rooms at different temperatures (16, 26, 36°C) and in a nursery at different light intensities induced by shade cloth densities (200, 400, ...

Light intensity fluctuations on a layered microsphere irradiated by a monochromatic light wave: Modeling of an inhomogeneous cellular surface with numerical elements

International Nuclear Information System (INIS)

Choi, Moon Kyu

2007-01-01

The inhomogeneity of crystalline or amorphous unit cells of material is treated by the numerical boundary element method. This paper is especially about the effect of perturbed refractive index (or potential energy) of a material on the light intensity inside a layered microsphere when it is irradiated by monochromatic unpolarized plane light wave. The resultant light intensities on the particle surface show noise-like fluctuations depending on various parameters such as the material refractive indices, the light wavelength, the particle and core size, the numerical surface element size, etc. Both the numerical results and the experiments from a few other groups agree that large light absorption occurs just in a small wavelength range

Targets for production of high-intensity radioactive ion-beams

International Nuclear Information System (INIS)

Hagebo, E.; Hoff, P.; Steffensen, K.

1991-01-01

The recent developments of target systems for production of high intensity radioactive ion-beams at the ISOLDE mass separators is described. Methods for chemically selective production through separation of molecular ions are outlined and the effects of the addition of reactive gases has been studied. Results and further possible applications in the light element region are discussed. (author) 10 refs.; 9 figs.; 1 tab

Hematoporphyrin-sensitized degradation of deoxyribose and DNA in high intensity near-UV picosecond pulsed laser photolysis

International Nuclear Information System (INIS)

Gantchev, T.G.; Lier, J.E. van; Grabner, G.; Keskinova, E.; Angelov, D.

1995-01-01

The photosensitized degradation of deoxyribose and DNA, using hematoporphyrin (HP) and picosecond laser pulses at high intensities was studied. Aldehyde formation from 2-deoxy-D-ribose and long-chain double-stranded DNA, when analyzed as a function of light intensity, followed a non-linear dependence, suggesting the involvement of multiphoton light absorption by HP. The degradation mechanism was studied by analysis of the yield dependence on excitation intensity and the effect of added radical scavengers. The participation of OH radicals in the degradation process was confirmed by spin trapping techniques. At low light intensities, added N 2 O largely increased product formation, suggesting that HP photoionization predominates under these conditions. At higher intensities (I ≥ 3 GW/cm 2 ) the product yield was not affected by N 2 O which, combined with spin trapping data, suggested that OH radical formation occurred, but that neither HP photoionization nor peroxy formation was involved. Single and double strand breaks in supercoiled plasmid DNA (pBR 322) confirmed the generation of OH or OH-like radicals during high-intensity excitation of HP. A mechanism involving a multistep excitation of HP, followed by resonance energy transfer to H 2 O resulting in dissociation to yield OH and H atoms, is proposed. (author)

Performance analysis of solar cell arrays in concentrating light intensity

Institute of Scientific and Technical Information of China (English)

Xu Yongfeng; Li Ming; Wang Liuling; Lin Wenxian; Xiang Ming; Zhang Xinghua; Wang Yunfeng; Wei Shengxian

2009-01-01

tage in concentrating light intensity. The output power has a -20 W/V coefficient and so cooling fluid must be used. Both heat energy and electrical power are then obtained with a solar trough concentrating photovoltaic/thermal system.

Morphological composition of cultivar of Urochloa brizantha under light intensities

Directory of Open Access Journals (Sweden)

Erikelly Aline Ribeiro de Santana

2013-12-01

Full Text Available The implementation of silvopastoral systems (SSP is a management option that gives good results for animal production, but the shading of the trees can alter production, growth behavior and morphological composition of the forage. The aim of the study was to evaluate the morphological composition of Urochloa brizantha cultivars Marandu and Piatã under natural light and artificial shading of 30 and 60%. The experiment was conducted at FMVZ - UNESP, Botucatu. The experimental design was a randomized block in factorial arrangement 3 x 2 (three shading levels: 0, 30 and 60% and two cultivars: Marandu and Piatã with three replications and repeated measures in time (3 cuts. Sample collection occurred when the cultivars reached in 35 cm of height. Significant effects (P<0.05 of cultivar x shade x cut interaction were observed on the dry matter production of leaves and stems (Table 1. The higher production of leaves and stems (P<0.05 occurred for Piatã under natural light in the third cut (3731 and 1920 kg/ha, respectively. The absence of shade favored greater leaf production, 35 and 27% higher than the reductions of 30 and 60% respectively. The increment of stems for Piatã under natural light is related to the increase of inflorescences. The leaf:stem ratio was higher (P< 0.05 for Marandu under natural light (Table 2, with effect from the interaction cultivar x brightness level. A significant effect (P<0.05 cultivar x level of light reduction for light interception parameter was detected (Table 2. For Marandu, light levels were not influenced (P<0.05 light traps (Table 2, being close to the 95% criterion used for pasture management, justified by the collection at the point of balance between forage productivity and nutritional content, and strong relationship with high input grazing. The results indicate that the morphological composition of the cultivars is modified by reducing the light intensity.

Laser-enhanced cavitation during high intensity focused ultrasound: An in vivo study

OpenAIRE

Cui, Huizhong; Zhang, Ti; Yang, Xinmai

2013-01-01

Laser-enhanced cavitation during high intensity focused ultrasound (HIFU) was studied in vivo using a small animal model. Laser light was employed to illuminate the sample concurrently with HIFU radiation. The resulting cavitation was detected with a passive cavitation detector. The in vivo measurements were made under different combinations of HIFU treatment depths, laser wavelengths, and HIFU durations. The results demonstrated that concurrent light illumination during HIFU has the potentia...

Light induced modulation instability of surfaces under intense illumination

KAUST Repository

Burlakov, V. M.

2013-12-17

We show that a flat surface of a polymer in rubber state illuminated with intense electromagnetic radiation is unstable with respect to periodic modulation. Initial periodic perturbation is amplified due to periodic thermal expansion of the material heated by radiation. Periodic heating is due to focusing-defocusing effects caused by the initial surface modulation. The surface modulation has a period longer than the excitation wavelength and does not require coherent light source. Therefore, it is not related to the well-known laser induced periodic structures on polymer surfaces but may contribute to their formation and to other phenomena of light-matter interaction.

Relationship between 3-Methyl-2,4-nonanedione Concentration and Intensity of Light-induced Off-odor in Soy Bean Oil.

Science.gov (United States)

Sano, Takashi; Iwahashi, Maiko; Imagi, Jun; Sato, Toshiro; Yamashita, Toshiyuki; Fukusaki, Eiichiro; Bamba, Takeshi

2016-05-01

A beany and green off-odor is developed in soy bean oil (SBO) under light-induced oxidative conditions. 3-Methyl-2,4-nonanedione (3-MND) was inferred as the compound responsible for the off-odor. In this study, we designed a simple quantification method for 3-MND in SBO, and evaluated the relationship between the 3-MND concentration and the intensity of the off-odor. 3-MND was analyzed by GC/MS with a thermal desorption unit system. By our method, the 3-MND concentration was found to increase with storage days and the SBO content under light exposure, and there was a high correlation between the measured 3-MND concentration and the intensity of the light-induced off-odor in SBO (R = 0.9586).

Physics of high intensity nanosecond electron source

International Nuclear Information System (INIS)

Herrera-Gomez, A.; Spicer, W.E.

1993-08-01

A new high-intensity, short-time electron source is now being used at the Stanford Linear Accelerator Center (SLAC). Using a GaAs negative affinity semiconductor in the construction of the cathode, it is possible to fulfill operation requirements such as peak currents of tens of amperes, peak widths of the order of nanoseconds, hundreds of hours of operation stability, and electron spin polarization. The cathode is illuminated with high intensity laser pulses, and photoemitted electrons constitute the yield. Because of the high currents, some nonlinear effects are present. Very noticeable is the so-called Charge Limit (CL) effect, which consists of a limit on the total charge in each pulse-that is, the total bunch charge stops increasing as the light pulse total energy increases. In this paper, we explain the mechanism of the CL and how it is caused by the photovoltaic effect. Our treatment is based on the Three-Step model of photoemission. We relate the CL to the characteristics of the surface and bulk of the semiconductor, such as doping, band bending, surface vacuum level, and density of surface states. We also discuss possible ways to prevent the Char's Level effect

Effect of Light Intensity and Photoperiod on Growth and Biochemical Composition of a Local Isolate of Nostoc calcicola.

Science.gov (United States)

Khajepour, Fateme; Hosseini, Seyed Abbas; Ghorbani Nasrabadi, Rasoul; Markou, Giorgos

2015-08-01

A study was conducted to investigate the effect of light intensity (21, 42, and 63 μmol photons m(-2) s(-1)) and photoperiod (8:16, 12:12, and 16:8 h light/dark) on the biomass production and its biochemical composition (total carotenoids, chlorophyll a, phycoerythrin (PE), phycocyanin (PC) and allophycocyanin (APC), total protein, and carbohydrates) of a local isolate of Nostoc calcicola. The results revealed that N. calcicola prefers dim light; however, the most of the levels of light intensity and photoperiod investigated did not have a significant impact on biomass production. Increasing light intensity biomass content of chlorophyll a, PE, PC, APC, and total protein decreased, while total carotenoids and carbohydrate increased. The same behavior was observed also when light duration (photoperiod) increased. The interaction effect of increasing light intensity and photoperiod resulted in an increase of carbohydrate and total carotenoids, and to the decrease of chlorophyll a, PE, PC, APC, and total protein content. The results indicate that varying the light regime, it is capable to manipulate the biochemical composition of the local isolate of N. calcicola, producing either valuable phycobiliproteins or proteins under low light intensity and shorter photoperiods, or producing carbohydrates and carotenoids under higher light intensities and longer photoperiods.

Effect of Light Intensity for Optimum Biomass and Lipid Production from Scenedesmus dimorphus (Turpin) Kützing

Science.gov (United States)

Kurniawati, F. N.; Mahajoeno, E.; Sunarto; Sari, S. L. A.

2017-07-01

One source of alternative energy substitute for petroleum raw materials is renewable vegetable oils known as biodiesel. Biodiesel can be produced from microalgae, since it was more efficient and environmentally friendly. Scenedesmus dimorphus (Turpin) Kützing was developed as a source of biodiesel since it had potential of high lipid production. The aims of this research were to know the rate of growth of Scenedesmus dimorphus in different lighting and the optimimum light intensity for biomass and lipid production. This research used a completely randomized design consisting of 3 treatments with 3 replications. Treatments in this research were the light intensity, i.e. 7,500, 10,000, and 12,500 lux. Scenedesmus dimorphus was grew in Bold’s Basal Medium (BBM). Parameters observed in this research were the cell number, biomass and lipid production of S. dimorphus. Data were analyzed by ANOVA followed by DMRT 5%. The results showed that the optimum growth rate of S. dimorphus was in the intensity of 12,500 lux that was 100.80 x 106 cells.ml-1. The optimum production of biomass and lipids was in treatment 12,500 lux i.e; 1.1407 g.L-1 and 0.2520 g.L-1 (22.28% dry weight).

Effect of light intensity on ovarian gene expression, reproductive performance and body weight of rabbit does.

Science.gov (United States)

Sun, Liangzhan; Wu, Zhenyu; Li, Fuchang; Liu, Lei; Li, Jinglin; Zhang, Di; Sun, Chaoran

2017-08-01

The objective of the experiment was to find the minimum light intensity which could improve reproduction by examining its effect on ovarian gene expression, reproductive performance and body weight of rabbit does with three different light intensities: 60 (L), 80 (M), and 100 (H)lx. A total of 144 Rex-rabbits submitted to a 49-day reproductive regimen were used in this study. Ovaries were collected and relative abundance of mRNA for ovarian proteins of interest was examined with real-time PCR. Amount of protein for proteins of interest was examined by immunohistochemistry. Reproductive performance and doe bodyweight of the first three consecutive reproductive periods after initiation of the light intensity treatments were evaluated. The results provided evidence that light intensity had no effect on relative abundance of estradiol receptor-α (ER-α), follicle stimulating hormone receptor (FSHR), luteinizing hormone receptor (LHR), gonadotropin releasing hormone receptor 1 (GnRHR1) and progesterone receptor (PGR) mRNA. The relative abundance of growth hormone receptor (GHR) mRNA was, however, greater in Group L than M and H (Plight intensities (P>0.05). The bodyweight of the does in Group L was greater than the other two groups at first insemination, second insemination and the second postpartum period (P0.05). These observations suggest that light intensity between 60 and 100lx has no effect on the reproductive performance of rabbit does, however, the amounts of GHR mRNA and growth hormone (GH) protein were affected and the greater light intensity had a negative effect on bodyweight between the time of the first insemination and the second partum period. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of photoperiod length and light intensity on some welfare criteria, carcass, and meat quality characteristics in broilers

Directory of Open Access Journals (Sweden)

Evrim Dereli Fidan

Full Text Available ABSTRACT The objective of this study was to investigate the effects of photoperiod length and light intensity on leg and eye health, tonic immobility, some blood parameters, carcass, and meat quality characteristics in broilers. A total of 272 one-day-old male broiler chicks (Ross 308 were randomly assigned to four treatment groups based on the photoperiod length (23L:1D or increasing duration of light and light intensity (20 lux vs. dim light with four replicates. In this study, photoperiod lenght had no effect on incidence of foot pad and hock burn. On the other hand, the effect of photoperiod lenght had significant influence on the gait score. The incidences of gait score (3 + 4 + 5 in bright and dim light groups was found as 21.4 and 41.0% in broilers, respectively. In addition, the effect of light intensity had statistical significance on gait score. The tonic immobility duration in 20 lux and dim light groups were 271.53 and 226.78 s, respectively, and tonic immobility duration was unaffected by light intensity. All the blood parameters, except for triglyceride, were not affected by light intensity. The dim light had a negative effect on broiler welfare as demonstrated by increased eye weight and dimensions. Cold carcass yield and whole breast and wing yields were lower in the dim light group than in 20 lux light intensity. The broilers kept with dim light had lower breast meat ultimate pH (6.19 and L* values (54.30 than those reared with 20 lux. These findings have a lot of implications on the use of increasing photoperiod and bright light to improve leg an eye health benefits for the broiler welfare in broilers.

Statistical properties of intensity of partially polarised semiconductor laser light backscattered by a single-mode optical fibre

International Nuclear Information System (INIS)

Alekseev, A E; Potapov, V T; Gorshkov, B G

2015-01-01

We report the results of studying statistical properties of the intensity of partially polarised coherent light backscattered by a single mode optical fibre. An expression is derived for the deviation of the backscattered light intensity depending on the scattering region length, the degree of the light source coherence and the degree of scattered light polarisation. It is shown that the backscattered light in a fibre scattered-light interferometer is partially polarised with the polarisation degree P = 1/3 in the case of external perturbations of the interferometer fibre. (scattering of light)

Biocapture of CO2 by Different Microalgal-Based Technologies for Biogas Upgrading and Simultaneous Biogas Slurry Purification under Various Light Intensities and Photoperiods

Directory of Open Access Journals (Sweden)

Pengfei Guo

2018-03-01

Full Text Available Co-cultivation of microalgae and microbes for pollutant removal from sewage is considered as an effective wastewater treatment method. The aim of this study is to screen the optimal photoperiod, light intensity and microalgae co-cultivation method for simultaneously removing nutrients in biogas slurry and capturing CO2 in biogas. The microalgae–fungi pellets are deemed to be a viable option because of their high specific growth rate and nutrient and CO2 removal efficiency under the photoperiod of 14 h light:10 h dark. The order of both the biogas slurry purification and biogas upgrading is ranked the same, that is Chlorella vulgaris–Ganoderma lucidum > Chlorella vulgaris–activated sludge > Chlorella vulgaris under different light intensities. For all cultivation methods, the moderate light intensity of 450 μmol m−2 s−1 is regarded as the best choice. This research revealed that the control of photoperiod and light intensity can promote the biological treatment process of biogas slurry purification and biogas upgrading using microalgal-based technology.

Biocapture of CO2 by Different Microalgal-Based Technologies for Biogas Upgrading and Simultaneous Biogas Slurry Purification under Various Light Intensities and Photoperiods

Science.gov (United States)

Guo, Pengfei; Zhang, Yuejin; Zhao, Yongjun

2018-01-01

Co-cultivation of microalgae and microbes for pollutant removal from sewage is considered as an effective wastewater treatment method. The aim of this study is to screen the optimal photoperiod, light intensity and microalgae co-cultivation method for simultaneously removing nutrients in biogas slurry and capturing CO2 in biogas. The microalgae–fungi pellets are deemed to be a viable option because of their high specific growth rate and nutrient and CO2 removal efficiency under the photoperiod of 14 h light:10 h dark. The order of both the biogas slurry purification and biogas upgrading is ranked the same, that is Chlorella vulgaris–Ganoderma lucidum > Chlorella vulgaris–activated sludge > Chlorella vulgaris under different light intensities. For all cultivation methods, the moderate light intensity of 450 μmol m−2 s−1 is regarded as the best choice. This research revealed that the control of photoperiod and light intensity can promote the biological treatment process of biogas slurry purification and biogas upgrading using microalgal-based technology. PMID:29543784

High-intensity laser physics

International Nuclear Information System (INIS)

Mohideen, U.

1993-01-01

This thesis is a study of the effect of high intensity lasers on atoms, free electrons and the generation of X-rays from solid density plasmas. The laser produced 50 milli Joule 180 femto sec pulses at 5 Hz. This translates to a maximum intensity of 5 x 10 18 W/cm 2 . At such high fields the AC stark shifts of atoms placed at the focus is much greater than the ionization energy. The characteristics of multiphoton ionization of atoms in intense laser fields was studied by angle resolved photoelectron spectroscopy. Free electrons placed in high intensity laser fields lead to harmonic generation. This phenomenon of Nonlinear Compton Scattering was theoretically investigated. Also, when these high intensity pulses are focused on solids a hot plasma is created. This plasma is a bright source of a short X-ray pulse. The pulse-width of X-rays from these solid density plasmas was measured by time-resolved X-ray spectroscopy

Influence of intensive light exposure on the complex impedance of polymer light-emitting diodes

Directory of Open Access Journals (Sweden)

Fábio Rogério Cury

2008-06-01

Full Text Available In this work we investigated the effect of visible radiation on the electrical properties of poly[(2-methoxy-5-hexyloxy-p-phenylenevinylene]- MH-PPV films and light emitting diodes. Complex impedance measurements of (Au or ITO/MH-PPV/(Au or Al samples were carried out at room temperature and exposed to white light. Over the frequency range from 100 mHz to 2 MHz, the electrical results of Au/MH-PPV/Au was dominated by the Cole-Cole approach, where the electrode influence is negligible. However, some additional influence of the interface was observed to occur when Al was used as electrode. These effects were observed under both dark and visible-light illumination conditions. A simple model based on resistor-capacitor parallel circuits was developed to represent the complex impedance of the samples, thereby separating bulk and interface contributions. We observed that the polymer electrical resistivity decreased while the dielectric constant of the polymer and the thickness of the Al/MH-PPV layer were almost constant with increasing light intensity. The decrease of the polymer layer resistance comes from a better charge injection due to a light induced dissociation of positive charge carriers at the electrode.

Productivity of Chlorella sorokiniana in a short light-path (SLP) panel photobioreactor under high irradiance

NARCIS (Netherlands)

Cuaresma, M.; Janssen, M.G.J.; Vilchez, C.; Wijffels, R.H.

2009-01-01

Maximal productivity of a 14 mm light-path panel photobioreactor under high irradiance was determined. Under continuous illumination of 2,100 µmol photons m-2 s-1 with red light emitting diodes (LEDs) the effect of dilution rate on photobioreactor productivity was studied. The light intensity used

An Integrated Response of Trichodesmium erythraeum IMS101 Growth and Photo-Physiology to Iron, CO2, and Light Intensity.

Science.gov (United States)

Boatman, Tobias G; Oxborough, Kevin; Gledhill, Martha; Lawson, Tracy; Geider, Richard J

2018-01-01

We have assessed how varying CO 2 (180, 380, and 720 μatm) and growth light intensity (40 and 400 μmol photons m -2 s -1 ) affected Trichodesmium erythraeum IMS101 growth and photophysiology over free iron (Fe') concentrations between 20 and 9,600 pM. We found significant iron dependencies of growth rate and the initial slope and maximal relative PSII electron transport rates (rP m ). Under iron-limiting concentrations, high-light increased growth rates and rP m ; possibly indicating a lower allocation of resources to iron-containing photosynthetic proteins. Higher CO 2 increased growth rates across all iron concentrations, enabled growth to occur at lower Fe' concentrations, increased rP m and lowered the iron half saturation constants for growth (K m ). We attribute these CO 2 responses to the operation of the CCM and the ATP spent/saved for CO 2 uptake and transport at low and high CO 2 , respectively. It seems reasonable to conclude that T. erythraeum IMS101 can exhibit a high degree of phenotypic plasticity in response to CO 2 , light intensity and iron-limitation. These results are important given predictions of increased dissolved CO 2 and water column stratification (i.e., higher light exposures) over the coming decades.

An Integrated Response of Trichodesmium erythraeum IMS101 Growth and Photo-Physiology to Iron, CO2, and Light Intensity

Directory of Open Access Journals (Sweden)

Tobias G. Boatman

2018-04-01

Full Text Available We have assessed how varying CO2 (180, 380, and 720 μatm and growth light intensity (40 and 400 μmol photons m−2 s−1 affected Trichodesmium erythraeum IMS101 growth and photophysiology over free iron (Fe′ concentrations between 20 and 9,600 pM. We found significant iron dependencies of growth rate and the initial slope and maximal relative PSII electron transport rates (rPm. Under iron-limiting concentrations, high-light increased growth rates and rPm; possibly indicating a lower allocation of resources to iron-containing photosynthetic proteins. Higher CO2 increased growth rates across all iron concentrations, enabled growth to occur at lower Fe′ concentrations, increased rPm and lowered the iron half saturation constants for growth (Km. We attribute these CO2 responses to the operation of the CCM and the ATP spent/saved for CO2 uptake and transport at low and high CO2, respectively. It seems reasonable to conclude that T. erythraeum IMS101 can exhibit a high degree of phenotypic plasticity in response to CO2, light intensity and iron-limitation. These results are important given predictions of increased dissolved CO2 and water column stratification (i.e., higher light exposures over the coming decades.

Light Intensity-Dependent Modulation of Chlorophyll b Biosynthesis and Photosynthesis by Overexpression of Chlorophyllide a Oxygenase in Tobacco1[C][OA

Science.gov (United States)

Biswal, Ajaya K.; Pattanayak, Gopal K.; Pandey, Shiv S.; Leelavathi, Sadhu; Reddy, Vanga S.; Govindjee; Tripathy, Baishnab C.

2012-01-01

Chlorophyll b is synthesized by the oxidation of a methyl group on the B ring of a tetrapyrrole molecule to a formyl group by chlorophyllide a oxygenase (CAO). The full-length CAO from Arabidopsis (Arabidopsis thaliana) was overexpressed in tobacco (Nicotiana tabacum) that grows well at light intensities much higher than those tolerated by Arabidopsis. This resulted in an increased synthesis of glutamate semialdehyde, 5-aminolevulinic acid, magnesium-porphyrins, and chlorophylls. Overexpression of CAO resulted in increased chlorophyll b synthesis and a decreased chlorophyll a/b ratio in low light-grown as well as high light-grown tobacco plants; this effect, however, was more pronounced in high light. The increased potential of the protochlorophyllide oxidoreductase activity and chlorophyll biosynthesis compensated for the usual loss of chlorophylls in high light. Increased chlorophyll b synthesis in CAO-overexpressed plants was accompanied not only by an increased abundance of light-harvesting chlorophyll proteins but also of other proteins of the electron transport chain, which led to an increase in the capture of light as well as enhanced (40%–80%) electron transport rates of photosystems I and II at both limiting and saturating light intensities. Although the quantum yield of carbon dioxide fixation remained unchanged, the light-saturated photosynthetic carbon assimilation, starch content, and dry matter accumulation increased in CAO-overexpressed plants grown in both low- and high-light regimes. These results demonstrate that controlled up-regulation of chlorophyll b biosynthesis comodulates the expression of several thylakoid membrane proteins that increase both the antenna size and the electron transport rates and enhance carbon dioxide assimilation, starch content, and dry matter accumulation. PMID:22419827

Size variability of the unit building block of peripheral light-harvesting antennas as a strategy for effective functioning of antennas of variable size that is controlled in vivo by light intensity.

Science.gov (United States)

Taisova, A S; Yakovlev, A G; Fetisova, Z G

2014-03-01

This work continuous a series of studies devoted to discovering principles of organization of natural antennas in photosynthetic microorganisms that generate in vivo large and highly effective light-harvesting structures. The largest antenna is observed in green photosynthesizing bacteria, which are able to grow over a wide range of light intensities and adapt to low intensities by increasing of size of peripheral BChl c/d/e antenna. However, increasing antenna size must inevitably cause structural changes needed to maintain high efficiency of its functioning. Our model calculations have demonstrated that aggregation of the light-harvesting antenna pigments represents one of the universal structural factors that optimize functioning of any antenna and manage antenna efficiency. If the degree of aggregation of antenna pigments is a variable parameter, then efficiency of the antenna increases with increasing size of a single aggregate of the antenna. This means that change in degree of pigment aggregation controlled by light-harvesting antenna size is biologically expedient. We showed in our previous work on the oligomeric chlorosomal BChl c superantenna of green bacteria of the Chloroflexaceae family that this principle of optimization of variable antenna structure, whose size is controlled by light intensity during growth of bacteria, is actually realized in vivo. Studies of this phenomenon are continued in the present work, expanding the number of studied biological materials and investigating optical linear and nonlinear spectra of chlorosomes having different structures. We show for oligomeric chlorosomal superantennas of green bacteria (from two different families, Chloroflexaceae and Oscillochloridaceae) that a single BChl c aggregate is of small size, and the degree of BChl c aggregation is a variable parameter, which is controlled by the size of the entire BChl c superantenna, and the latter, in turn, is controlled by light intensity in the course of cell

Verification of the light intensity from halogens curing lamps in comparison with the manufacturer's specifications

International Nuclear Information System (INIS)

Morales Ramirez, Elvis

2011-01-01

The light intensity emitted from halogens curing lamps is measured to determine if photoactivation units utilized in the Caja Costarricense de Seguro Social are complied with the manufacturer's specifications of the lamp and the resin. The light intensity mW/cm 2 from halogens curing lamps operated by odontologist of the Caja Costarricense de Seguro Social is compared with the manufacturer's specifications of the lamp. The light intensity is compared with the manufacturer's specifications of the resin. The results obtained are analyzed to specify that lamp or lamps have presented light intensities lower to indication of the manufacturer. A list of recommendations is performed for each Servicio de Odontologia of the Caja Costarricense de Seguro Social of the Region Central Sur of the results reported [es

The instantaneous light-intensity function of a fluorescent lamp

Energy Technology Data Exchange (ETDEWEB)

Gluskin, Emanuel [Holon Institute of Technology, 52 Golomb St., Holon 58102 (Israel): Electrical Engineering Department, Ben-Gurion University, Beer-Sheva 84105 (Israel)]. E-mail: gluskin@ee.bgu.ac.il; Topalis, Frangiskos V. [Technical University of Athens, School of Electrical and Computer Engineering, 9 Iroon Politechniou St., 15780 Athens (Greece); Kateri, Ifigenia [Technical University of Athens, School of Electrical and Computer Engineering, 9 Iroon Politechniou St., 15780 Athens (Greece); Bisketzis, Nikolas [Technical University of Athens, School of Electrical and Computer Engineering, 9 Iroon Politechniou St., 15780 Athens (Greece)

2006-05-08

Using some simple physics and 'system' considerations, the instantaneous light intensity function {psi}(t) of a fluorescent lamp fed via a regular ballast from the 50-60 Hz line is argued to be {psi}(t)={psi}{sub min}+bp(t), where p(t) is the instantaneous power function of the lamp, and b is a constant, and experiment confirms this formula well. The main frequency of {psi}(t), the very significant singularity of its waveform, and the relative intensity of the ripple, i.e., the depth of the modulation, are the focus. The results are important for research into the vision problem that some humans (autistic, but others, too) experience regarding fluorescent light. The inertia of the processes in the lamp which are responsible for the light emission, provides some nonzero emission at the instants when p(t) has zeros. The smaller the volume of the tube and the mass of the gas are, the more weakly the inertia of the processes is expressed, and the relatively smaller is {psi}{sub min}. However, it should be very difficult to theoretically obtain {psi}(t), in particular {psi}{sub min}, from the very complicated physics of the low-pressure discharge in the tube. We conclude that {psi}{sub min} has to be connected with the (also easily measured) lamp's inductance. The work should attract more attention of the physicists to the properties of the common fluorescent lamps. escent lamps.

Effects of day-time exposure to different light intensities on light-induced melatonin suppression at night.

Science.gov (United States)

Kozaki, Tomoaki; Kubokawa, Ayaka; Taketomi, Ryunosuke; Hatae, Keisuke

2015-07-04

Bright nocturnal light has been known to suppress melatonin secretion. However, bright light exposure during the day-time might reduce light-induced melatonin suppression (LIMS) at night. The effective proportion of day-time light to night-time light is unclear; however, only a few studies on accurately controlling both day- and night-time conditions have been conducted. This study aims to evaluate the effect of different day-time light intensities on LIMS. Twelve male subjects between the ages of 19 and 23 years (mean ± S.D., 20.8 ± 1.1) gave informed consent to participate in this study. They were exposed to various light conditions (day-time light conditions). They were then exposed to bright light (300 lx) again between 01:00 and 02:30 (night-time light exposure). They provided saliva samples before (00:55) and after night-time light exposure (02:30). A one-tailed paired t test yielded significant decrements of melatonin concentration after night-time light exposure under day-time dim, 100- and 300-lx light conditions. No significant differences exist in melatonin concentration between pre- and post-night-time light exposure under day-time 900- and 2700-lx light conditions. Present findings suggest the amount of light exposure needed to prevent LIMS caused by ordinary nocturnal light in individuals who have a general life rhythm (sleep/wake schedule). These findings may be useful in implementing artificial light environments for humans in, for example, hospitals and underground shopping malls.

Generating structured light with phase helix and intensity helix using reflection-enhanced plasmonic metasurface at 2 μm

Science.gov (United States)

Zhao, Yifan; Du, Jing; Zhang, Jinrun; Shen, Li; Wang, Jian

2018-04-01

Mid-infrared (2-20 μm) light has been attracting great attention in many areas of science and technology. Beyond the extended wavelength range from visible and near-infrared to mid-infrared, shaping spatial structures may add opportunities to grooming applications of mid-infrared photonics. Here, we design and fabricate a reflection-enhanced plasmonic metasurface and demonstrate efficient generation of structured light with the phase helix and intensity helix at 2 μm. This work includes two distinct aspects. First, structured light (phase helix, intensity helix) generation at 2 μm, which is far beyond the ability of conventional spatial light modulators, is enabled by the metasurface with sub-wavelength engineered structures. Second, the self-referenced intensity helix against environmental noise is generated without using a spatially separated light. The demonstrations may open up advanced perspectives to structured light applications at 2 μm, such as phase helix for communications and non-communications (imaging, sensing) and intensity helix for enhanced microscopy and advanced metrology.

Carcinogenesis related to intense pulsed light and UV exposure

DEFF Research Database (Denmark)

Hedelund, L; Lerche, C; Wulf, H C

2006-01-01

This study examines whether intense pulsed light (IPL) treatment has a carcinogenic potential itself or may influence ultraviolet (UV)-induced carcinogenesis. Secondly, it evaluates whether UV exposure may influence IPL-induced side effects. Hairless, lightly pigmented mice (n=144) received three...... observation period. Side effects were evaluated clinically. No tumors appeared in untreated control mice or in just IPL-treated mice. Skin tumors developed in UV-exposed mice independently of IPL treatments. The time it took for 50% of the mice to first develop skin tumor ranged from 47 to 49 weeks...... in preoperative UV-exposed mice (p=0.94) and from 22 to 23 weeks in pre- and postoperative UV-exposed mice (p=0.11). IPL rejuvenation of lightly pigmented skin did not induce pigmentary changes (p=1.00). IPL rejuvenation of UV-pigmented skin resulted in an immediate increased skin pigmentation and a subsequent...

Effect of Light Intensity on the Relative Dominance of Toxigenic and Nontoxigenic Strains of Microcystis aeruginosa ▿

Science.gov (United States)

LeBlanc Renaud, Susan; Pick, Frances R.; Fortin, Nathalie

2011-01-01

In aquatic ecosystems, the factors that regulate the dominance of toxin-producing cyanobacteria over non-toxin-producing strains of the same species are largely unknown. One possible hypothesis is that limiting resources lead to the dominance of the latter because of the metabolic costs associated with toxin production. In this study, we tested the effect of light intensity on the performance of a microcystin-producing strain of Microcystis aeruginosa (UTCC 300) when grown in mixed cultures with non-microcystin-producing strains with similar intrinsic growth rates (UTCC 632 and UTCC 633). The endpoints measured included culture growth rates, microcystin concentrations and composition, and mcyD gene copy numbers determined using quantitative PCR (Q-PCR). In contrast to the predicted results, under conditions of low light intensity (20 μmol·m−2·s−1), the toxigenic strain became dominant in both of the mixed cultures based on gene copy numbers and microcystin concentrations. When grown under conditions of high light intensity (80 μmol·m−2·s−1), the toxigenic strain still appeared to dominate over nontoxigenic strain UTCC 632 but less so over strain UTCC 633. Microcystins may not be so costly to produce that toxigenic cyanobacteria are at a disadvantage in competition for limiting resources. PMID:21841026

Effect of high-intensity irradiation from dental photopolymerization on the isolated and superfused vertebrate retina.

Science.gov (United States)

Rassaei, Mohammad; Thelen, Martin; Abumuaileq, Ramzi; Hescheler, Jürgen; Lüke, Matthias; Schneider, Toni

2013-03-01

Light or electromagnetic radiation may damage the neurosensory retina during irradiation of photopolymerizing resinous materials. Direct and indirect effects of irradiation emitted from polymerisation curing light may represent a severe risk factor for the eyes and the skin of the lamp operators, as well as for the patient's oral mucosa. Bovine superfused retinas were used to record their light-evoked electroretinogram (ERG) as ex vivo ERGs. Both the a- and the b-waves were used as indicators for retinal damage on the functional level. The isolated retinas were routinely superfused with a standard nutrient solution under normoglycemic conditions (5 mM D-glucose). The change in the a- and b-wave amplitude and implicit time, caused by low and high intensity irradiation, was calculated and followed over time. From the results, it can be deduced that the irradiation from LED high-power lamps affects severely the normal physiological function of the bovine retina. Irradiations of 1,200 lx irreversibly damaged the physiological response. In part, this may be reversible at lower intensities, but curing without using the appropriate filter will bleach the retinal rhodopsin to a large extent within 20 to 40 s of standard application times. Constant exposure to intense ambient irradiation affects phototransduction (a-wave) as well as transretinal signalling. The proper use of the UV- and blue-light filtering device is highly recommended, and may prevent acute and long lasting damage of the neurosensory retina.

The effect of light intensity on prey detection behavior in two Lake Malawi cichlids, Aulonocara stuartgranti and Tramitichromis sp.

Science.gov (United States)

Schwalbe, Margot A B; Webb, Jacqueline F

2015-04-01

Two sand-dwelling cichlids from Lake Malawi (Aulonocara stuartgranti, Tramitichromis sp.) that feed on benthic invertebrates, but have different lateral line phenotypes, use lateral line and/or visual cues to detect prey under light versus dark conditions. The current study examined how ecologically relevant variation in light intensity [0-800 lux (lx)] influences detection of prey (mobile, immobile) in each species by analyzing six behavioral parameters. Both species fed at light intensities ≥1 lx and trends in behavior among light intensities were informative. However, prey type and/or time of day (but not light intensity) predicted all four parameters analyzed with generalized linear mixed models in A. stuartgranti, whereas the interaction of light intensity and time of day predicted three of these parameters in Tramitichromis sp. Data suggest that the critical light intensity is 1-12 lx for both species, that the integration of visual and lateral line input explains differences in detection of mobile and immobile prey and behavioral changes at the transition from 1 to 0 lx in A. stuartgranti, and that Tramitichromis sp. likely uses binocular vision to locate prey. Differences in the sensory biology of species that exploit similar prey will have important implications for the trophic ecology of African cichlid fishes.

Effects of UV light intensity on electrochemical wet etching of SiC for the fabrication of suspended graphene

Science.gov (United States)

O, Ryong-Sok; Takamura, Makoto; Furukawa, Kazuaki; Nagase, Masao; Hibino, Hiroki

2015-03-01

We report on the effects of UV light intensity on the photo assisted electrochemical wet etching of SiC(0001) underneath an epitaxially grown graphene for the fabrication of suspended structures. The maximum etching rate of SiC(0001) was 2.5 µm/h under UV light irradiation in 1 wt % KOH at a constant current of 0.5 mA/cm2. The successful formation of suspended structures depended on the etching rate of SiC. In the Raman spectra of the suspended structures, we did not observe a significant increase in the intensity of the D peak, which originates from defects in graphene sheets. This is most likely explained by the high quality of the single-crystalline graphene epitaxially grown on SiC.

High intensity circular proton accelerators

International Nuclear Information System (INIS)

Craddock, M.K.

1987-12-01

Circular machines suitable for the acceleration of high intensity proton beams include cyclotrons, FFAG accelerators, and strong-focusing synchrotrons. This paper discusses considerations affecting the design of such machines for high intensity, especially space charge effects and the role of beam brightness in multistage accelerators. Current plans for building a new generation of high intensity 'kaon factories' are reviewed. 47 refs

Thermographic analysis of photodynamic therapy with intense pulsed light and needle-free injection photosensitizer delivery: an animal study

Science.gov (United States)

Requena, Michelle B.; Stringasci, Mirian D.; Pratavieira, Sebastião.; Vollet-Filho, José Dirceu; de Nardi, Andrigo B.; Escobar, Andre; da Rocha, Rozana W.; Bagnato, Vanderlei S.; de Menezes, Priscila F. C.

2018-02-01

The photodynamic therapy (PDT) is a therapeutic modality that depends mostly on photosensitizer (PS), light and molecular oxygen species. However, there are still technical limitations in clinical PDT that are under constant development, particularly concerning PS and light delivery. Intense Pulsed Light (IPL) sources are systems able to generate pulses of high energy with polychromatic light. IPL is a technique mainly used in the cosmetic area to perform various skin treatments for therapeutic and aesthetic applications. The goals of this study were to determine temperature variance during the application of IPL in porcine skin model, and the PDT effects using this light source with PS delivery by a commercial high pressure, needle-free injection system. The PSs tested were Indocyanine Green (ICG) and Photodithazine (PDZ), and the results showed an increase bellow 10 °C in the skin surface using a thermographic camera to measure. In conclusion, our preliminary study demonstrated that IPL associated with needle-free injection PS delivery could be a promising alternative to PDT.

Magnetic orientation in birds: non-compass responses under monochromatic light of increased intensity.

Science.gov (United States)

Wiltschko, Wolfgang; Munro, Ursula; Ford, Hugh; Wiltschko, Roswitha

2003-10-22

Migratory Australian silvereyes (Zosterops lateralis) were tested under monochromatic light at wavelengths of 424 nm blue and 565 nm green. At a low light level of 7 x 10(15) quanta m(-2) s(-1) in the local geomagnetic field, the birds preferred their seasonally appropriate southern migratory direction under both wavelengths. Their reversal of headings when the vertical component of the magnetic field was inverted indicated normal use of the avian inclination compass. A higher light intensity of 43 x 10(15) quanta m(-2) s(-1), however, caused a fundamental change in behaviour: under bright blue, the silvereyes showed an axial tendency along the east-west axis; under bright green, they showed a unimodal preference of a west-northwesterly direction that followed a shift in magnetic north, but was not reversed by inverting the vertical component of the magnetic field. Hence it is not based on the inclination compass. The change in behaviour at higher light intensities suggests a complex interaction between at least two receptors. The polar nature of the response under bright green cannot be explained by the current models of light-dependent magnetoreception and will lead to new considerations on these receptive processes.

Effect of different intensities of physical activity on cardiometabolic markers and vascular and cardiac function in adult rats fed with a high-fat high-carbohydrate diet

OpenAIRE

Romeo B. Batacan, Jr; Mitch J. Duncan; Vincent J. Dalbo; Geraldine L. Buitrago; Andrew S. Fenning

2018-01-01

Background: Physical activity (PA) and diet are 2 lifestyle factors that affect cardiometabolic risk. However, data on how a high-fat high-carbohydrate (HFHC) diet influences the effect of different intensities of PA on cardiometabolic health and cardiovascular function in a controlled setting are yet to be fully established. This study investigated the effect of sedentary behavior, light-intensity training (LIT), and high-intensity interval training (HIIT) on cardiometabolic markers and vasc...

High Resolution Near Infrared Spectrometer to Study the Zodiacal Light Spectrum

Science.gov (United States)

Kutyrev, Alexander; Arendt, R.; Dwek, E.; Moseley, S. H.; Silverberg, R.; Rapchun, D.

2007-12-01

We are developing a near infrared spectrometer for measuring solar absorption lines in the zodiacal light in the near infrared region. R. Reynolds at el. (2004, ApJ 612, 1206) demonstrated that observing single Fraunhofer line can be a powerful tool for extracting zodiacal light parameters based on their measurements of the profile of the Mg I line at 5184 A. We are extending this technique to the near infrared with the primary goal of measuring the absolute intensity of the zodiacal light. This measurement will provide the crucial information needed to accurately subtract zodiacal emission from the DIRBE measurements to get a much higher quality measurement of the extragalactic IR background. The instrument design is based on a dual Fabry-Perot interferometer with a narrow band filter. Its double etalon design allows to achieve high spectral contrast to reject the bright out of band telluric OH emission. High spectral contrast is absolutely necessary to achieve detection limits needed to accurately measure the intensity of the absorption line. We present the design, estimated performance of the instrument with the expected results of the observing program. The project is supported by NASA ROSES-APRA grant.

Measurement and removal of cladding light in high power fiber systems

Science.gov (United States)

Walbaum, Till; Liem, Andreas; Schreiber, Thomas; Eberhardt, Ramona; Tünnermann, Andreas

2018-02-01

The amount of cladding light is important to ensure longevity of high power fiber components. However, it is usually measured either by adding a cladding light stripper (and thus permanently modifying the fiber) or by using a pinhole to only transmit the core light (ignoring that there may be cladding mode content in the core area). We present a novel noninvasive method to measure the cladding light content in double-clad fibers based on extrapolation from a cladding region of constant average intensity. The method can be extended to general multi-layer radially symmetric fibers, e.g. to evaluate light content in refractive index pedestal structures. To effectively remove cladding light in high power systems, cladding light strippers are used. We show that the stripping efficiency can be significantly improved by bending the fiber in such a device and present respective experimental data. Measurements were performed with respect to the numerical aperture as well, showing the dependency of the CLS efficiency on the NA of the cladding light and implying that efficiency data cannot reliably be given for a certain fiber in general without regard to the properties of the guided light.

High intensity surface plasma waves, theory and PIC simulations

Science.gov (United States)

Raynaud, M.; Héron, A.; Adam, J.-C.

2018-01-01

With the development of intense (>1019 W cm-2) short pulses (≤25 fs) laser with very high contrast, surface plasma wave (SPW) can be explored in the relativistic regime. As the SPW propagates with a phase velocity close to the speed of light it may results in a strong acceleration of electron bunches along the surface permitting them to reach relativistic energies. This may be important e.g. for applications in the field of plasma-based accelerators. We investigate in this work the excitation of SPWs on grating preformed over-dense plasmas for laser intensities ranging from 1019 up to 1021 W cm-2. We discuss the nature of the interaction with respect to the solid case in which surface plasmon can be resonantly excited with weak laser intensity. In particular, we show the importance of the pulse duration and focalization of the laser beam on the amplitude of the SPW.

The Effects of Light Intensity, Casing Layers, and Layering Styles on Royal Sun Medicinal Mushroom, Agaricus brasiliensis (Higher Basidiomycetes) Cultivation in Turkey.

Science.gov (United States)

Adanacioglu, Neşe; Boztok, Kaya; Akdeniz, Ramazan Cengiz

2015-01-01

The aim of this research is to evaluate the effects of light intensity, casing layers, and layering styles on the production of the culinary-medicinal mushroom Agaricus brasiliensis in Turkey. The experiments were designed in split-split plots and replicated twice. Three different light intensities-I1, 350 lux; I2, 450 lux; and I3, 750 lux-were used in main plots as environmental factors. A mixture of 4 different casing layers- peat (100%), peat-perlite (75%:25%), peat-clinoptilolite (75%:25%), and peat-perlite-clinoptilolite (60%:20%:20%)-were used at split plots and at split plots. S1, a flat, 3-cm casing layer; S2, a flat, 5-cm casing layer; and S3, casing soil ridges 10 cm wide × 4 cm high, 10 cm apart, were deposited on top of 1-cm overall soil casing layers. At the end of the harvest phase, the total yield was estimated per 100 kg of substrate. Biological efficiency (percentage) was determined from the fresh weight of the mushrooms and the dry weight of the compost at the end of the harvesting period. The highest total yield (7.2 kg/100 kg compost) and biological efficiency (27.63%) were achieved from I2 × peat-perlite-clinoptilolite × S2 treatment. Influence of light intensity, casing layer, layering style, and their interaction in treatments with color values (L*, a*, b*, chroma*, and hue*) also were examined. It has been shown that within color values, chroma* (saturation) values of mushroom caps were affected by light intensity, casing layer, and layering style treatments and light intensity × casing layer treatments and the brightness of mushroom caps tended to increase as light intensity increased.

Fracto-mechanoluminescent light emission of EuD4TEA-PDMS composites subjected to high strain-rate compressive loading

Science.gov (United States)

Ryu, Donghyeon; Castaño, Nicolas; Bhakta, Raj; Kimberley, Jamie

2017-08-01

The objective of this study is to understand light emission characteristics of fracto-mechanoluminescent (FML) europium tetrakis(dibenzoylmethide)-triethylammonium (EuD4TEA) crystals under high strain-rate compressive loading. As a sensing material that can play a pivotal role for the self-powered impact sensor technology, it is important to understand transformative light emission characteristics of the FML EuD4TEA crystals under high strain-rate compressive loading. First, EuD4TEA crystals were synthesized and embedded into polydimethylsiloxane (PDMS) elastomer to fabricate EuD4TEA-PDMS composite test specimens. Second, the prepared EuD4TEA-PDMS composites were tested using the modified Kolsky bar setup equipped with a high-speed camera. Third, FML light emission was captured to yield 12 bit grayscale video footage, which was processed to quantify the FML light emission. Finally, quantitative parameters were generated by taking into account pixel values and population of pixels of the 12 bit grayscale images to represent FML light intensity. The FML light intensity was correlated with high strain-rate compressive strain and strain rate to understand the FML light emission characteristics under high strain-rate compressive loading that can result from impact occurrences.

High-energy gamma-ray beams from Compton-backscattered laser light

International Nuclear Information System (INIS)

Sandorfi, A.M.; LeVine, M.J.; Thorn, C.E.; Giordano, G.; Matone, G.

1983-01-01

Collisions of light photons with relativistic electrons have previously been used to produce polarized #betta#-ray beams with modest (-10%) resolution but relatively low intensity. In contrast, the LEGS project (Laser + Electron Gamma Source) at Brookhaven will produce a very high flux (>2 x 10 7 s - 1 ) of background-free polarized #betta# rays whose energy will be determined to a high accuracy (δE = 2.3 MeV). Initially, 300(420)-MeV #betta# rays will be produced by backscattering uv light from the new 2.5(3.0)-GeV X-ray storage ring of the National Synchrotron Light Source (NSLS). The LEGS facility will operate as one of many passive users of the NSLS. In a later stage of the project, a Free Electron Laser is expectred to extend the #betta#-ray energy up to 700 MeV

High-energy gamma-ray beams from Compton-backscattered laser light

Energy Technology Data Exchange (ETDEWEB)

Sandorfi, A.M.; LeVine, M.J.; Thorn, C.E.; Giordano, G.; Matone, G.

1983-01-01

Collisions of light photons with relativistic electrons have previously been used to produce polarized ..gamma..-ray beams with modest (-10%) resolution but relatively low intensity. In contrast, the LEGS project (Laser + Electron Gamma Source) at Brookhaven will produce a very high flux (>2 x 10/sup 7/ s/sup -1/) of background-free polarized ..gamma.. rays whose energy will be determined to a high accuracy (..delta..E = 2.3 MeV). Initially, 300(420)-MeV ..gamma.. rays will be produced by backscattering uv light from the new 2.5(3.0)-GeV X-ray storage ring of the National Synchrotron Light Source (NSLS). The LEGS facility will operate as one of many passive users of the NSLS. In a later stage of the project, a Free Electron Laser is expectred to extend the ..gamma..-ray energy up to 700 MeV.

Effects of light intensity on the morphology and CAM photosynthesis of Vanilla planifolia Andrews

Directory of Open Access Journals (Sweden)

María Claudia Díez

2017-01-01

Full Text Available Vanilla planifolia is a neotropical orchid, whose fruits produce the natural vanilla, a fundamental ingredient for the food and cosmetic industry. Because of its importance in the world market, it is cultivated in many tropical countries and recently its cultivation has started in Colombia. This species requires shade for its development; however, the optimal of light conditions are unknown. This work evaluates the effect of different light intensities on CAM photosynthesis, physiology, morphology, and growth of this species. For this, vanilla seedlings were subjected to four treatments of relative illumination (RI (T1=8%, T2=17%, T3=31% and T4=67%. Most CO2 assimilation occurred along night in all treatments, which confirms that vanilla is a strong CAM species. Plants grown under high lighting (67% RI had almost half of the photosynthesis in treatments of intermediate lighting (17 and 31%, which is consistent with the lower nocturnal acid accumulation in that treatment. Likewise, the photochemical efficiency of photosystem II (Fv / Fm showed that in plants of the 67% RI occurred high radiation stress. On the other hand, vanilla plants reached greater length, leaf area, and total biomass when grown under intermediate radiation (17 and 31% RI. These results suggest that high radiation alters the functioning of vanilla plants, inhibiting photosynthesis and growth, and that highly shaded environments not significantly affected the CAM photosynthesis of vanilla; however, in the long-term this species showed higher photosynthesis and growth under intermediate levels of radiation

Multi-photon ionization of atoms and molecules by intense XUV-FEL light. Application to methanol and ethanol molecules

International Nuclear Information System (INIS)

Sato, Takahiro; Iwasaki, Atsushi; Okino, Tomoya; Yamanouchi, Kaoru; Yagishita, Akira; Yazawa, Hiroki; Kannari, Fumihiko; Aoyama, Makoto; Yamakawa, Koichi; Midorikawa, Katsumi; Nakano, Hidetoshi; Yabashi, Makina; Nagasono, Mitsuru; Higashiya, Atsushi; Togashi, Tadashi; Ishikawa, Tetsuya

2009-01-01

The photo-ionization processes of methanol (CH 3 OH, CD 3 OH) and ethanol (C 2 H 5 OH) and their dependences on the wavelength and the light-field intensity were investigated using intense XUV light at 51 and 61 nm at the XUV free electron laser facility of RIKEN SPring-8 Center. The light field intensity achieved at 51 nm was found to be intense enough to generate Ar 7+ from Ar. It was confirmed that (1) the stable dications, CH 2 OH 2+ and CH 2 OD 2+ , were produced respectively from CH 3 OH and CD 3 OH, and C 2 H 2 OH 2+ from CH 2 H 5 OH via the direct and/or stepwise two-photon absorption, and (2) C + and CH + were produced from C 2 H 5 OH via the stepwise two-photon absorption of the XUV light. It was also confirmed by the formation of H 3 O + from CH 3 OH and C 2 H 5 OH, and HOD 2 + from CD 3 OH that hydrogen migration processes were induced by the irradiation of the intense XUV light. (author)

Electron Parametric Instabilities Driven by Relativistically Intense Laser Light in Plasma

Science.gov (United States)

Barr, H. C.; Mason, P.; Parr, D. M.

1999-08-01

A unified treatment of electron parametric instabilities driven by ultraintense laser light in plasma is described. It is valid for any intensity, polarization, plasma density, and scattering geometry. The method is applied to linearly polarized light in both underdense plasma and overdense plasma accessible by self-induced transparency. New options arise which are hybrids of stimulated Raman scattering, the two plasmon decay, the relativistic modulational and filamentation instabilities, and stimulated harmonic generation. There is vigorous growth over a wide range of wave numbers and harmonics.

Modeling and simulation of a 3D-CMOS silicon photodetector for low-intensity light detection

Science.gov (United States)

Sabri Alirezaei, Iman; Burte, Edmund P.

2016-03-01

This paper presents a design and simulation of a novel high performance 3D-silicon photodetector for implementing in the low intensity light detection at room temperature (300K). The photodetector is modeled by inspiration of general MEMS fabrication to make a 3D- structure in the silicon substrate using a bulk micromachining process, and based on a complementary metal-oxide semiconductor (CMOS) technology. The design includes a vertical n+/p junction as an optical window for lateral illumination. The simulation is carried out using COMSOL Multiphysics relying on theoretical and physical concepts, and then, the assessment of the results is done by the numerical analysis with SILVACO (Atlas) device simulator. Light is regarded as a monochromatic beam with a wavelength of 633nm that is placed 1μm far from the optical window. The simulation is considered under the reverse bias dc voltage in the steadystate. We present photocurrent-voltage (Iph-V) characteristics under different light intensities (2… 10[mW/cm2]), and dark current-voltage (Id-V) characteristics. Comparative studies of sensitivity dependence on the dopant concentration in the substrate as an intrinsic region are accomplished utilizing two different p-type silicon substrates with 1×1015 [1/cm3] and 4×1012 [1/cm3] doping concentration. Moreover, the sensitivity is evaluated with respect to the active substrate thickness. The simulated results confirmed that the high optical sensitivity of the photodetector with low dark current can be realized in this model.

Evaluation of different pre-slaughter light intensities and fasting duration in broilers

Directory of Open Access Journals (Sweden)

IB Ramão

2011-12-01

Full Text Available The aim of this study was to determine the effects of different levels of light intensity (0, 5 or 20 lx and different pre-slaughter feed fasting duration (3, 6, 9, 12 and 15 hours on the parameters body weight loss, carcass yield, commercial cuts yield, water carcass retention, bacterial counts and breast meat pH. A number of 72 broiler chickens at 45 days of age (Cobb 500 strain was distributed in three chambers, in a total of 24 broilers per chamber. The results showed that feed fasting significantly influenced (p0.05. The presence of feed in the crop and gizzard did not depend on light intensity, but was affected by pre-slaughter feed fasting duration. Bacterial counts decreased with feed fasting duration (p<0.05.

Surfaces in the interaction of intense long wavelength laser light with plasmas

International Nuclear Information System (INIS)

Jones, R.D.

1985-01-01

The role of surface in the interaction of intense CO 2 laser light with plasmas is reviewed. The collisionless absorption of long wavelength light is discussed. Specific comments on the role of ponderomotive forces and profile steepening on resonant absorption are made. It is shown that at intensities above 10 15 W/cm 2 the absorption is determined by ion acoustic-like surface modes. It is demonstrated experimentally that harmonics up to the forty-sixth can be generated in steep density profiles. Computer simulations and theoretical mechanisms for this phenomena are presented. The self generation of magnetic fields on surfaces is discussed. The role these fields play in the lateral transport of energy, the insulation of the target from hot electrons, and the acceleration of fast ions is discussed

Report from the NSLS workshop: Sources and applications of high intensity uv-vuv light

Energy Technology Data Exchange (ETDEWEB)

Johnson, E.D.; Hastings, J.B. (eds.)

1990-01-01

A workshop was held to evaluate sources and applications of high intensity, ultra violet (UV) radiation for biological, chemical, and materials sciences. The proposed sources are a UV free electron laser (FEL) driven by a high brightness linac and undulators in long, straight sections of a specially designed low energy (400 MeV) storage ring. These two distinct types of sources will provide a broad range of scientific opportunities that were discussed in detail during the workshop.

Report from the NSLS workshop: Sources and applications of high intensity uv-vuv light

Energy Technology Data Exchange (ETDEWEB)

Johnson, E.D.; Hastings, J.B. [eds.

1990-12-31

A workshop was held to evaluate sources and applications of high intensity, ultra violet (UV) radiation for biological, chemical, and materials sciences. The proposed sources are a UV free electron laser (FEL) driven by a high brightness linac and undulators in long, straight sections of a specially designed low energy (400 MeV) storage ring. These two distinct types of sources will provide a broad range of scientific opportunities that were discussed in detail during the workshop.

Report from the NSLS workshop: Sources and applications of high intensity uv-vuv light

International Nuclear Information System (INIS)

Johnson, E.D.; Hastings, J.B.

1990-01-01

A workshop was held to evaluate sources and applications of high intensity, ultra violet (UV) radiation for biological, chemical, and materials sciences. The proposed sources are a UV free electron laser (FEL) driven by a high brightness linac and undulators in long, straight sections of a specially designed low energy (400 MeV) storage ring. These two distinct types of sources will provide a broad range of scientific opportunities that were discussed in detail during the workshop

Far infrared spectroscopy of high-Tc superconductors at the National Synchrotron Light Source

International Nuclear Information System (INIS)

Perkowitz, S.; Williams, G.P.

1989-01-01

This paper reports the first far infrared transmission spectra for micron-thick films of high-T c rare-earth superconductors such as DyBaCuO, with implications for the superconducting gap. Spectra were obtained at Brookhaven's National Synchrotron Light Source, a new high-intensity, broad-band millimeter to infrared source. The National Synchrotron Light Source at Brookhaven National Laboratory, known for powerful X-ray and UV output, is also a high-intensity (10 to 1000 times above a black body), high-brightness (intensity per solid angle), broad-band, picosecond, millimeter to infrared source. These features make it valuable for far-infrared condensed matter experiments, especially those in highly absorbing or extremely small systems. A first application has been to measure very small infrared transmissions through thick bulk-like high-T c superconducting films. Preliminary measurements through films of the conventional superconductor Nb 3 Ge established techniques. These were followed by the first measurements (to the author's knowledge) through micron-thick films of high-T c rare-earth superconductors such as DyBaCuO over 10-300 cm -1 , which includes the superconducting gap according to BCS or moderately strong-coupled theory. The authors discuss the transmission evidence bearing on the existence of a gap and other important features of high-T c superconductors, and describe the synchrotron and instrumentation features which make possible these unusual measurements

Antioxidant capacity reduced in scallions grown under elevated CO 2 independent of assayed light intensity

Science.gov (United States)

Levine, Lanfang H.; Paré, Paul W.

2009-10-01

Long-duration manned space missions mandate the development of a sustainable life support system and effective countermeasures against damaging space radiation. To mitigate the risk of inevitable exposure to space radiation, cultivation of fresh fruits and vegetables rich in antioxidants is an attractive alternative to pharmacological agents. However it has yet to be established whether antioxidant properties of crops can be preserved or enhanced in a space environment where environmental conditions differ from that which plants have acclimated to on earth. Scallion ( Allium fistulosum) rich in antioxidant vitamins C and A, and flavonoids was used as a model plant to study the impact of a range of CO 2 concentrations and light intensities that are likely encountered in a space habitat on food quality traits. Scallions were hydroponically grown in controlled environmental chambers under a combination of 3 CO 2 concentrations of 400, 1200 and 4000 μmol mol -1 and 3 light intensity levels of 150, 300, 450 μmol m -2 s -1. Total antioxidant activity (TAA) of scallion extracts was determined using a radical cation scavenging assay. Both elevated CO 2 and increasing light intensity enhanced biomass accumulation, but effects on TAA (based on dry weight) differed. TAA was reduced for plants grown under elevated CO 2, but remained unchanged with increases in light intensity. Elevated CO 2 stimulated greater biomass production than antioxidants, while an increase in photosynthetic photo flux promoted the synthesis of antioxidant compounds at a rate similar to that of biomass. Consequently light is a more effective stimulus than CO 2 for antioxidant production.

Electromagnetic Coupling Between High Intensity LHC Beams and the Synchrotron Radiation Monitor Light Extraction System

CERN Document Server

Andreazza, W; Bravin, E; Caspers, F; Garlasch`e, M; Gras, J; Goldblatt, A; Lefevre, T; Jones, R; Metral, E; Nosych, A; Roncarolo_, F; Salvant, B; Trad, G; Veness, R; Vollinger, C; Wendt, M

2013-01-01

The CERN LHC is equipped with two Synchrotron Radiation Monitor (BSRT) systems used to characterise transverse and longitudinal beam distributions. Since the end of the 2011 LHC run the light extraction system, based on a retractable mirror, has suffered deformation and mechanical failure that is correlated to the increase in beam intensity. Temperature probes have associated these observations to a strong heating of the mirror support with a dependence on the longitudinal bunch length and shape, indicating the origin as electromagnetic coupling between the beam and the structure. This paper combines all this information with the aim of characterising and improving the system in view of its upgrade during the current LHC shutdown. Beam-based observations are presented along with electromagnetic and thermomechanical simulations and complemented by laboratory measurements, including the study of the RF properties of different mirror bulk and coating materials.

Rewriting the rules governing high intensity interactions of light with matter

Science.gov (United States)

Borisov, Alex B.; McCorkindale, John C.; Poopalasingam, Sankar; Longworth, James W.; Simon, Peter; Szatmári, Sándor; Rhodes, Charles K.

2016-04-01

The trajectory of discovery associated with the study of high-intensity nonlinear radiative interactions with matter and corresponding nonlinear modes of electromagnetic propagation through material that have been conducted over the last 50 years can be presented as a landscape in the intensity/quantum energy [I-ħω] plane. Based on an extensive series of experimental and theoretical findings, a universal zone of anomalous enhanced electromagnetic coupling, designated as the fundamental nonlinear domain, can be defined. Since the lower boundaries of this region for all atomic matter correspond to ħω ~ 103 eV and I  ≈  1016 W cm-2, it heralds a future dominated by x-ray and γ-ray studies of all phases of matter including nuclear states. The augmented strength of the interaction with materials can be generally expressed as an increase in the basic electromagnetic coupling constant in which the fine structure constant α  →  Z 2 α, where Z denotes the number of electrons participating in an ordered response to the driving field. Since radiative conditions strongly favoring the development of this enhanced electromagnetic coupling are readily produced in self-trapped plasma channels, the processes associated with the generation of nonlinear interactions with materials stand in natural alliance with the nonlinear mechanisms that induce confined propagation. An experimental example involving the Xe (4d105s25p6) supershell for which Z  ≅  18 that falls in the specified anomalous nonlinear domain is described. This yields an effective coupling constant of Z 2 α  ≅  2.4  >  1, a magnitude comparable to the strong interaction and a value rendering as useless conventional perturbative analyses founded on an expansion in powers of α. This enhancement can be quantitatively understood as a direct consequence of the dominant role played by coherently driven multiply-excited states in the dynamics of the coupling. It is also

Numerical evaluation of droplet sizing based on the ratio of fluorescent and scattered light intensities (LIF/Mie technique)

International Nuclear Information System (INIS)

Charalampous, Georgios; Hardalupas, Yannis

2011-01-01

The dependence of fluorescent and scattered light intensities from spherical droplets on droplet diameter was evaluated using Mie theory. The emphasis is on the evaluation of droplet sizing, based on the ratio of laser-induced fluorescence and scattered light intensities (LIF/Mie technique). A parametric study is presented, which includes the effects of scattering angle, the real part of the refractive index and the dye concentration in the liquid (determining the imaginary part of the refractive index). The assumption that the fluorescent and scattered light intensities are proportional to the volume and surface area of the droplets for accurate sizing measurements is not generally valid. More accurate sizing measurements can be performed with minimal dye concentration in the liquid and by collecting light at a scattering angle of 60 deg. rather than the commonly used angle of 90 deg. Unfavorable to the sizing accuracy are oscillations of the scattered light intensity with droplet diameter that are profound at the sidescatter direction (90 deg.) and for droplets with refractive indices around 1.4.

Compton scattering at high intensities

Energy Technology Data Exchange (ETDEWEB)

Heinzl, Thomas, E-mail: thomas.heinzl@plymouth.ac.u [University of Plymouth, School of Mathematics and Statistics, Drake Circus, Plymouth PL4 8AA (United Kingdom)

2009-12-01

High-intensity Compton scattering takes place when an electron beam is brought into collision with a high power laser. We briefly review the main intensity signatures using the formalism of strong-field quantum electrodynamics.

Effect of light intensity on the performance of silicon solar cell ...

African Journals Online (AJOL)

This work, presents the intense light effect on electrical parameters of silicon solar such as short circuit current, open circuit voltage, series and shunt resistances, maximum power, conversion efficiency, fill factor. After the resolution of the continuity equation which leads to the solar cell photocurrent and photovoltage ...

effect of light intensity on the performance of silicon solar cell

African Journals Online (AJOL)

(Received 31 January 2017; Revision Accepted 7 April 2017). ABSTRACT. This work, presents the intense light effect on electrical parameters of silicon solar such as short circuit current, open circuit voltage, series and shunt ... level, which is a source of carrier photogeneration,. 123. Martial Zoungrana, Laboratory of ...

The success of the cyanobacterium Cylindrospermopsis raciborskii in freshwaters is enhanced by the combined effects of light intensity and temperature

Directory of Open Access Journals (Sweden)

Sylvia Bonilla

2016-06-01

Full Text Available Toxic cyanobacterial blooms in freshwaters are thought to be a consequence of the combined effects of anthropogenic eutrophication and climate change. It is expected that climate change will affect water mixing regimes that alter the water transparency and ultimately the light environment for phytoplankton. Blooms of the potentially toxic cyanobacterium Cylindrospermopsis raciborskii are expanding from tropical towards temperate regions. Several hypotheses have been proposed to explain this expansion, including an increase in water temperature due to climate change and the high phenotypic plasticity of the species that allows it to exploit different light environments. We performed an analysis based on eight lakes in tropical, subtropical and temperate regions to examine the distribution and abundance of C. raciborskii in relation to water temperature and transparency. We then conducted a series of short-term factorial experiments that combined three temperatures and two light intensity levels using C. raciborskii cultures alone and in interaction with another cyanobacterium to identify its growth capacity. Our results from the field, in contrast to predictions, showed no differences in dominance (>40% to the total biovolume of C. raciborskii between climate regions. C. raciborskii was able to dominate the phytoplankton in a wide range of light environments (euphotic zone = 1.5 to 5 m, euphotic zone/mixing zone ratio <0.5 to >1.5. Moreover, C. raciborskii was capable of dominating the phytoplankton at low temperatures (<15°C. Our experimental results showed that C. raciborskii growing in interaction was enhanced by the increase of the temperature and light intensity. C. raciborskii growth in high light intensities and at a wide range of temperatures, suggests that any advantage that this species may derive from climate change that favors its dominance in the phytoplankton is likely due to changes in the light environment rather than changes in

Effect of high intensity vs. soft-start halogen irradiation on light-cured resin-based composites. Part I. Temperature rise and polymerization shrinkage.

Science.gov (United States)

Hofmann, Norbert; Markert, Tanja; Hugo, Burkard; Klaiber, Bernd

2003-12-01

To determine polymerization shrinkage kinetics and temperature rise of light-cured resin-based composites after high intensity vs. soft-start quartz tungsten halogen irradiation. Shrinkage kinetics was evaluated using the "deflecting disk technique", modified for simultaneous measurement of temperature within the resin-based composite using a thermocouple. Additional irradiations after 60 and 65 minutes allowed the determination of temperature rises caused by radiation or by reaction heat. Four hybrids (Filtek Z250, Herculite, Solitaire 2, Tetric Ceram), an inhomogeneously filled hybrid (InTen-S) and a microfill (Filtek A110, formerly Silux Plus) were cured using the quartz tungsten halogen units Astralis 10 and Optilux 501 in the high intensity (A10 HiPo: 10 seconds at 1300 mW/cm2; OL Boost: 10 seconds at 1140 mW/cm2) or soft-start modes (A10 Pulse: increase to 700 mW/cm2 within 10 seconds, three periods of 2 seconds at 1300 mW/cm2 alternating with two periods of 2 seconds at 700 mW/cm2; OL Ramp: exponential increase within 10 seconds, followed by 10 seconds at 1140 mW/cm2). The soft-start protocols produced less contraction, and polymerization shrinkage started later and progressed slower (or: more slowly), compared to high intensity irradiation [correction]. The lowest shrinkage was observed for InTen-S, followed by Filtek Z250 and A110, whereas Solitaire 2, Herculite and Tetric Ceram scored highest for this parameter. Temperature rise was caused more or less equally by radiation and by reaction heat and reached values of up to 28.9 degrees C relative to a baseline of 37 degrees C. For some combinations of curing modes and resin-based composites, less heat was generated by the soft-start protocols and by Optilux 501.

Electronic Dimmable Ballasts for High-Intensity Discharge Sodium Vapor and Metal Halide Lamps

Science.gov (United States)

Boulanger, Richard

2002-01-01

Two types of high-intensity discharge lamps were tested using dimmable ballasts. The main purpose for evaluating this lighting system was to determine its efficacy for saving power. Whereas previous variable level lighting systems for HID lamps in Advanced Life Support applications were adjustable in two or three steps using capacitive switching, this system allows for continuously adjustable lamp output. This type of lighting system when used as part of an Advanced Life Support biomass production system would provide only the amount of light energy a crop needed at any particular point in its growth cycle. Since most of the equivalent system mass in an ALS system is from the light energy required to grow the crops, controlling that light energy dynamically over a continuous range of operation would dramatically reduce the power consumption and reduce system mass.

Effect of Different Light Intensities on Total Phenolics and Flavonoids Synthesis and Anti-oxidant Activities in Young Ginger Varieties (Zingiber officinale Roscoe)

Science.gov (United States)

Ghasemzadeh, Ali; Jaafar, Hawa Z. E.; Rahmat, Asmah; Wahab, Puteri Edaroyati Megat; Halim, Mohd Ridzwan Abd

2010-01-01

Nowadays, phytochemicals and antioxidants in plants are raising interest in consumers for their roles in the maintenance of human health. Phenolics and flavonoids are known for their health-promoting properties due to protective effects against cardiovascular disease, cancers and other disease. Ginger (Zingiber officinale) is one of the traditional folk medicinal plants and it is widely used in cooking in Malaysia. In this study, four levels of glasshouse light intensities (310, 460, 630 and 790 μmol m−2s−1) were used in order to consider the effect of light intensity on the production, accumulation and partitioning of total phenolics (TP), total flavonoids (TF) and antioxidant activities in two varieties of Malaysian young ginger (Zingiber officinale). TF biosynthesis was highest in the Halia Bara variety under 310 μmol m−2s−1 and TP was high in this variety under a light intensity of 790 μmol m−2s−1. The highest amount of these components accumulated in the leaves and after that in the rhizomes. Also, antioxidant activities determined by the 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) assay in both of varieties, increased significantly (p ≤ 0.01) with increasing TF concentration, and high antioxidant activity was observed in the leaves of Halia Bara grown under 310 μmol m−2s−1. The ferric reducing (FRAP) activity of the rhizomes was higher than that of the leaves in 310 μmol m−2s−1 of sun light. This study indicates the ability of different light intensities to enhance the medicinal components and antioxidant activities of the leaves and young rhizomes of Zingiber officinale varieties. Additionally, this study also validated their medicinal potential based on TF and TP contents. PMID:21152306

Effect of Different Light Intensities on Total Phenolics and Flavonoids Synthesis and Anti-oxidant Activities in Young Ginger Varieties (Zingiber officinale Roscoe

Directory of Open Access Journals (Sweden)

Ali Ghasemzadeh

2010-10-01

Full Text Available Nowadays, phytochemicals and antioxidants in plants are raising interest in consumers for their roles in the maintenance of human health. Phenolics and flavonoids are known for their health-promoting properties due to protective effects against cardiovascular disease, cancers and other disease. Ginger (Zingiber officinale is one of the traditional folk medicinal plants and it is widely used in cooking in Malaysia. In this study, four levels of glasshouse light intensities (310, 460, 630 and 790 μmol m−2s−1 were used in order to consider the effect of light intensity on the production, accumulation and partitioning of total phenolics (TP, total flavonoids (TF and antioxidant activities in two varieties of Malaysian young ginger (Zingiber officinale. TF biosynthesis was highest in the Halia Bara variety under 310 μmol m−2s−1 and TP was high in this variety under a light intensity of 790 μmol m−2s−1. The highest amount of these components accumulated in the leaves and after that in the rhizomes. Also, antioxidant activities determined by the 1,1-Diphenyl-2-picryl-hydrazyl (DPPH assay in both of varieties, increased significantly (p ≤ 0.01 with increasing TF concentration, and high antioxidant activity was observed in the leaves of Halia Bara grown under 310 μmol m−2s−1. The ferric reducing (FRAP activity of the rhizomes was higher than that of the leaves in 310 μmol m−2s−1 of sun light. This study indicates the ability of different light intensities to enhance the medicinal components and antioxidant activities of the leaves and young rhizomes of Zingiber officinale varieties. Additionally, this study also validated their medicinal potential based on TF and TP contents.

Excitation of random intense single-cycle light-pulse chains in optical fiber

International Nuclear Information System (INIS)

Ding, Y C; Zhang, F L; Gao, J B; Chen, Z Y; Lin, C Y; Yu, M Y

2014-01-01

Excitation of intense periodic single-cycle light pulses in a stochastic background arising from continuous wave stimulated Brillouin scattering (SBS) in a long optical fiber with weak optical feedback is found experimentally and modeled theoretically. Such intense light-pulse chains occur randomly and the optical feedback is a requirement for their excitation. The probability of these forms, among the large number of experimental output signals with identifiable waveforms, appearing is only about 3%, with the remainder exhibiting regular SBS characteristics. It is also found that pulses with low period numbers appear more frequently and the probability distribution for their occurrence in terms of the pulse power is roughly L-shaped, like that for rogue waves. The results from a three-wave-coupling model for SBS including feedback phase control agree well qualitatively with the observed phenomena. (paper)

Interactive effects of photoperiod and light intensity on blood physiological and biochemical reactions of broilers grown to heavy weights.

Science.gov (United States)

Olanrewaju, H A; Purswell, J L; Collier, S D; Branton, S L

2013-04-01

The effects of photoperiod, light intensity, and their interaction on blood acid-base balance, metabolites, and electrolytes in broiler chickens under environmentally controlled conditions were examined in 2 trials. A 3 × 3 factorial experiment in a randomized complete block design was used in this study. In each trial, all treatment groups were provided 23L:1D with 20 lx of intensity from placement to 7 d, and then subjected to the treatments. The 9 treatments consisted of 3 photoperiods [long/continuous (23L:1D) from d 8 to 56, regular/intermittent (2L:2D), and short/nonintermittent (8L:16D) from d 8 to 48 and 23L:1D from d 49 to 56, respectively] and exposure to 3 light intensities (10, 5.0, and 0.5 lx) from d 8 through d 56 at 50% RH. Feed and water were provided ad libitum. Venous blood samples were collected on d 7, 14, 28, 42, and 56. Main effects indicated that short/nonintermittent photoperiod significantly (P light intensity, or their interaction. There was no effect of light intensity on most of the blood variables examined. Acid-base regulation during photoperiod and light intensity exposure did not deteriorate despite a lower pH and higher partial pressure of CO2 with normal HCO3(-). These results indicate that continuous exposure of broiler chickens to varying light intensities had a minor effect on blood physiological variables, whereas the short photoperiod markedly affected most blood physiological variables without inducing physiological stress in broilers.

Low light intensity and nitrogen starvation modulate the chlorophyll content of Scenedesmus dimorphus.

Science.gov (United States)

Ferreira, V S; Pinto, R F; Sant'Anna, C

2016-03-01

Chlorophyll is a photosynthetic pigment found in plants and algal organisms and is a bioproduct with human health benefits and a great potential for use in the food industry. The chlorophyll content in microalgae strains varies in response to environmental factors. In this work, we assessed the effect of nitrogen depletion and low light intensity on the chlorophyll content of the Scenedesmus dimorphus microalga. The growth of S. dimorphus under low light intensity led to a reduction in cell growth and volume as well as increased cellular chlorophyll content. Nitrogen starvation led to a reduction in cell growth and the chlorophyll content, changes in the yield and productivity of chlorophylls a and b. Transmission electron microscopy was used to investigate the ultrastructural changes in the S. dimorphus exposed to nitrogen and light deficiency. In contrast to nitrogen depletion, low light availability was an effective mean for increasing the total chlorophyll content of green microalga S. dimorphus. The findings acquired in this work are of great biotechnological importance to extend knowledge of choosing the right culture condition to stimulate the effectiveness of microalgae strains for chlorophyll production purposes. © 2015 The Society for Applied Microbiology.

Side effects from intense pulsed light

DEFF Research Database (Denmark)

Thaysen-Petersen, Daniel; Erlendsson, Andres M; Nash, J F

2017-01-01

BACKGROUND AND OBJECTIVE: Intense pulsed light (IPL) is a mainstream treatment for hair removal. Side effects after IPL are known, but risk factors remain to be investigated. The objective of this study was to assess the contribution of skin pigmentation, fluence level, and ultraviolet radiation...... stacking of 46 J/cm2. Areas were subsequently randomized to no UVR or single solar-simulated UVR exposure of 3 Standard Erythema Dose at 30 minutes or 24 hours after IPL. Each area had a corresponding control, resulting in 15 treatment sites. Follow-up visits were scheduled up to 4 weeks after IPL. Outcome...... measures were: (i) blinded clinical skin reactions; (ii) objectively measured erythema and pigmentation; (iii) pain measured by visual analog scale (VAS); (iv) histology (H&E, Fontana-Masson); and (v) mRNA-expression of p53. RESULTS: Fifteen subjects with FST II-IV completed the protocol. IPL induced...

The role of low light intensity: A step towards understanding the connection between light, optic/lens and photovoltaic behavior for Sb2S3 thin-film solar cells

Science.gov (United States)

Lojpur, Vesna; Mitrić, Miodrag; Validžić, Ivana Lj

2018-05-01

We report here an optic/lens system that we used so far, for cooling the surface of solar cells, the reduction of light intensity and the change of light distribution that reaches the surface of the solar cell. The objective was to improve photovoltaic characteristics under very low light illumination, as well as to understand the connection between light, optic/lens and photovoltaic behavior for Sb2S3 thin-film solar cells. It was found that for all so far designed thin-film solar cells made and based on the synthesized Sb2S3, optics/lens system causes an increase in open circuit voltage (VOC) and short circuit current (ISC) and thus the efficiencies of made solar devices. Values of energy gaps for the thin-films made devices were in the range from 1.4 to 2 eV. Improvements of the photovoltaic response of the designed devices are found to be better at the lower light intensity (5% sun), than at higher intensities of light. For the same intensity of light used optic/lens improves the efficiency of the devices, by changing the light distribution. Other processes that are related to the optics/lens system, leading to an increase in ISC and VOC and consequently to an increase in efficiencies of the designed devices, are investigated.

Light Intensity and Carbon Dioxide Availability Impact Antioxidant Activity in Green Onions (Allium fistulosumm L)

Science.gov (United States)

Levine, Lanfang; Bisbee, Patricia; Pare, Paul

The prospect of long-duration manned space missions poses many challenges, including the development of a sustainable life support system and effective methods of space-radiation protection. To mitigate the risk of increased space-radiation, functional foods rich in antioxidant properties such as green onions are of particular interest. However it has yet to be established whether antioxidant properties can be preserved or enhanced in space environment where carbon dioxide, lighting intensity, gravity and pressure differ from which plants have acclimated to on earth. In this study, green onions (Allium fistulosumm L. cultivar Kinka) rich in antioxidant flavonoids are used as a model system to investigate variations in antioxidant capacity with plants grown under varying light intensities and CO2 concentrations. The antioxidant potential is determined using both radical cation scavenging and oxygen radical absorbance assays. For all light intensities assayed, antioxidant potential in water extract of green onions per gram biomass declined with CO2 increases up to 1200 ppm, and then leveled off with further CO2 increase to 4000 ppm. This inverse carbon dioxide versus antioxidant activity correlation suggests lower accumulation rates for water soluble antioxidant compounds compared to total biomass under increasing CO2 concentrations. The effect of increasing atmospheric CO2 concentration on antioxidant activity of ethanol extracts were light intensity dependent. The implications of these findings are discussed in the context of traditional plant antioxidants including vitamin C and the major onion flavonoid quercetin.

3D study of bifacial silicon solar cell under intense light ...

African Journals Online (AJOL)

This work presents a three-dimensional study of bifacial silicon solar cell under intense light concentration and under constant magnetic field. This approach is based on the resolution of the minority continuity equation, taking into account the distribution of the electric field in the bulk evaluated as a function of both majority ...

Ill-lighting syndrome: prevalence in shift-work personnel in the anaesthesiology and intensive care department of three Italian hospitals

Directory of Open Access Journals (Sweden)

Zanatta Paolo

2009-03-01

Full Text Available Abstract Background Light is one of the most important factors in our interaction with the environment; it is indispensable to visual function and neuroendocrine regulation, and is essential to our emotional perception and evaluation of the environment. Previous studies have focussed on the effects of prolonged anomalous exposure to artificial light and, in the field of work-related illness. Studies have been carried out on shift-work personnel, who are obliged to experience alterations in the physiological alternation of day and night, with anomalous exposure to light stimuli in hours normally reserved for sleep. In order to identify any signs and symptoms of the so-called ill-lighting syndrome, we carried out a study on a sample of anaesthesiologists and nurses employed in the operating theatres and Intensive Care Departments of three Italian hospitals. We measured the subjective emotional discomfort (stress experienced by these subjects, and its correlation with environmental discomfort factors, in particular the level of lighting, in their workplace. Methods We used a questionnaire developed by the Scandinavian teams who investigated Sick-Building Syndrome, that was self-administered on one day in the environments where the degree of illumination was measured according to UNIEN12464-1 regulations. Results Upon comparison of the types of exposure with the horizontal luminance values (lux measured ( 1500 lux and the degree of stress reported, (Intensive Care: mean stress = 55.8%, high stress = 34.6%; Operating Theatres: mean stress = 51.5%, high stress = 33.8%, it can be observed that the percentage of high stress was reduced as the exposure to luminance was increased, although this finding was not statistically significant. Conclusion We cannot share other authors' enthusiasm regarding the effects on workers well-being correlated to the use of fluorescent lighting. The stress level of our workers was found to be more heavily influenced by

Multi-photon ionization of atoms and molecules by intense XUV-FEL light. Application to methanol and ethanol molecules

Energy Technology Data Exchange (ETDEWEB)

Sato, Takahiro; Iwasaki, Atsushi; Okino, Tomoya; Yamanouchi, Kaoru [Tokyo Univ., School of Science, Tokyo (Japan); Yagishita, Akira [Institute of Materials Structure Science, Photon Factory, Tsukuba, Ibaraki (Japan); Yazawa, Hiroki; Kannari, Fumihiko [Keio Univ., Graduate School of Science and Technology, Yokohama, Kanagawa (Japan); Aoyama, Makoto; Yamakawa, Koichi [Japan Atomic Energy Agency, Kansai Photon Science Inst., Kizugawa, Kyoto (Japan); Midorikawa, Katsumi [RIKEN, Laser Technology Laboratory, Wako, Saitama (Japan); Nakano, Hidetoshi [NTT Corp., NTT Basic Research Laboratories, Atsugi, Kanagawa (Japan); Yabashi, Makina; Nagasono, Mitsuru; Higashiya, Atsushi; Togashi, Tadashi; Ishikawa, Tetsuya [RIKEN SPring-8 XFEL Project, Sayo, Hyogo (Japan)

2009-12-15

The photo-ionization processes of methanol (CH{sub 3}OH, CD{sub 3}OH) and ethanol (C{sub 2}H{sub 5}OH) and their dependences on the wavelength and the light-field intensity were investigated using intense XUV light at 51 and 61 nm at the XUV free electron laser facility of RIKEN SPring-8 Center. The light field intensity achieved at 51 nm was found to be intense enough to generate Ar{sup 7+} from Ar. It was confirmed that (1) the stable dications, CH{sub 2}OH{sup 2+} and CH{sub 2}OD{sup 2+}, were produced respectively from CH{sub 3}OH and CD{sub 3}OH, and C{sub 2}H{sub 2}OH{sup 2+} from CH{sub 2}H{sub 5}OH via the direct and/or stepwise two-photon absorption, and (2) C{sup +} and CH{sup +} were produced from C{sub 2}H{sub 5}OH via the stepwise two-photon absorption of the XUV light. It was also confirmed by the formation of H{sub 3}O{sup +} from CH{sub 3}OH and C{sub 2}H{sub 5}OH, and HOD{sub 2}{sup +} from CD{sub 3}OH that hydrogen migration processes were induced by the irradiation of the intense XUV light. (author)

Ultrabroad linewidth orange-emitting nanowires LED for high CRI laser-based white lighting and gigahertz communications

KAUST Repository

Janjua, Bilal

2016-08-10

Group-III-nitride laser diode (LD)-based solid-state lighting device has been demonstrated to be droop-free compared to light-emitting diodes (LEDs), and highly energy-efficient compared to that of the traditional incandescent and fluorescent white light systems. The YAG:Ce3+ phosphor used in LD-based solid-state lighting, however, is associated with rapid degradation issue. An alternate phosphor/LD architecture, which is capable of sustaining high temperature, high power density, while still intensity- and bandwidth-tunable for high color-quality remained unexplored. In this paper, we present for the first time, the proof-of-concept of the generation of high-quality white light using an InGaN-based orange nanowires (NWs) LED grown on silicon, in conjunction with a blue LD, and in place of the compound-phosphor. By changing the relative intensities of the ultrabroad linewidth orange and narrow-linewidth blue components, our LED/LD device architecture achieved correlated color temperature (CCT) ranging from 3000 K to above 6000K with color rendering index (CRI) values reaching 83.1, a value unsurpassed by the YAG-phosphor/blue-LD counterpart. The white-light wireless communications was implemented using the blue LD through on-off keying (OOK) modulation to obtain a data rate of 1.06 Gbps. We therefore achieved the best of both worlds when orange-emitting NWs LED are utilized as “active-phosphor”, while blue LD is used for both color mixing and optical wireless communications.

The influence of low intensities of light pollution on bat communities in a semi-natural context.

Directory of Open Access Journals (Sweden)

Aurelie Lacoeuilhe

Full Text Available Anthropogenic light pollution is an increasingly significant issue worldwide. Over the past century, the use of artificial lighting has increased in association with human activity. Artificial lights are suspected to have substantial effects on the ecology of many species, e.g., by producing discontinuities in the territories of nocturnal animals. We analyzed the potential influence of the intensity and type of artificial light on bat activity in a semi-natural landscape in France. We used a species approach, followed by a trait-based approach, to light sensitivity. We also investigated whether the effect of light could be related to foraging traits. We performed acoustic surveys at sites located along a gradient of light intensities to assess the activity of 15 species of bats. We identified 2 functional response groups of species: one group that was light-tolerant and one group that was light-intolerant. Among the species in the latter group that appear to be disadvantaged by lighting conditions, many are rare and threatened in Europe, whereas the species from the former group are better able to thrive in disturbed habitats such as lighted areas and may actually benefit from artificial lighting. Finally, several methods of controlling light pollution are suggested for the conservation of bat communities. Recommendations for light management and the creation of dim-light corridors are proposed; these strategies may play an important role in protecting against the impact of light pollution on nocturnal animals.

The influence of low intensities of light pollution on bat communities in a semi-natural context.

Science.gov (United States)

Lacoeuilhe, Aurelie; Machon, Nathalie; Julien, Jean-François; Le Bocq, Agathe; Kerbiriou, Christian

2014-01-01

Anthropogenic light pollution is an increasingly significant issue worldwide. Over the past century, the use of artificial lighting has increased in association with human activity. Artificial lights are suspected to have substantial effects on the ecology of many species, e.g., by producing discontinuities in the territories of nocturnal animals. We analyzed the potential influence of the intensity and type of artificial light on bat activity in a semi-natural landscape in France. We used a species approach, followed by a trait-based approach, to light sensitivity. We also investigated whether the effect of light could be related to foraging traits. We performed acoustic surveys at sites located along a gradient of light intensities to assess the activity of 15 species of bats. We identified 2 functional response groups of species: one group that was light-tolerant and one group that was light-intolerant. Among the species in the latter group that appear to be disadvantaged by lighting conditions, many are rare and threatened in Europe, whereas the species from the former group are better able to thrive in disturbed habitats such as lighted areas and may actually benefit from artificial lighting. Finally, several methods of controlling light pollution are suggested for the conservation of bat communities. Recommendations for light management and the creation of dim-light corridors are proposed; these strategies may play an important role in protecting against the impact of light pollution on nocturnal animals.

Light intensity modulation by coccoliths of Emiliania huxleyi as a micro-photo-regulator

Science.gov (United States)

Mizukawa, Yuri; Miyashita, Yuito; Satoh, Manami; Shiraiwa, Yoshihiro; Iwasaka, Masakazu

2015-09-01

In this study, we present experimental evidence showing that coccoliths have light-scattering anisotropy that contributes to a possible control of solar light exposure in the ocean. Changing the angle between the incident light and an applied magnetic field causes differences in the light-scattering intensities of a suspension of coccoliths isolated from Emiliania huxleyi. The magnetic field effect is induced by the diamagnetic torque force directing the coccolith radial plane perpendicular to the applied magnetic fields at 400 to 500 mT. The developed technique reveals the light-scattering anisotropies in the 3-μm-diameter floating coccoliths by orienting themselves in response to the magnetic fields. The detached coccolith scatters radially the light incident to its radial plane. The experimental results on magnetically oriented coccoliths show that an individual coccolith has a specific direction of light scattering, although the possible physiological effect of the coccolith remains for further study, focusing on the light-scattering anisotropies of coccoliths on living cells.

Impact of temperature and light intensity on triacylglycerol accumulation in marine microalgae

International Nuclear Information System (INIS)

Kurpan Nogueira, Daniel P.; Silva, Anita F.; Araújo, Ofélia Q.F.; Chaloub, Ricardo M.

2015-01-01

Triacylglycerol (TAG) productivity of Isochrysis galbana, Nannochloropsis oceanica and Phaeodactylum tricornutum was compared to study their suitability for biotechnological applications. Photoautotrophic batch cultures grown at 20 °C and 50 μmol photons m −2  s −1 showed that N. oceanica had the least TAG content and TAG productivity of the three microalgae. Hence, effects of temperature and light intensity on growth rate and accumulation of TAG were subsequently assessed only in I. galbana and P. tricornutum by cultivation at 20 and 30 °C under 50, 300 and 600 μmol photons m −2  s −1 . Although P. tricornutum did not grow at temperatures higher than 20 °C, an increase in both TAG content (from 28.37 to 39.53%) and productivity (from 15.58 to 31.39 mg L −1  d −1 ) was observed at the highest irradiance values. We also found that combined effects of temperature and light intensity enhanced TAG content (from 18.59 to 31.71%) and productivity (from 11.76 to 21.67 mg L −1  d −1 ) in I. galbana. - Highlights: • Productivity of oil and biomass in batch-cultured marine microalgae was compared. • Increase in temperature and irradiance rose oil productivity in Isochrysis galbana. • An increase in light intensity rose oil productivity in Phaeodactylum tricornutum. • Phaeodactylum tricornutum showed the highest productivity in biomass and neutral lipids

THE CYTOTOXIC EFFECTS OF LOW INTENSITY VISIBLE AND INFRARED LIGHT ON HUMAN BREAST CANCER (MCF7 CELLS

Directory of Open Access Journals (Sweden)

P Peidaee

2013-03-01

Full Text Available A concept of using low intensity light therapy (LILT as an alternative approach to cancer treatment is at early stages of development; while the therapeutic effects of LILT as a non-invasive treatment modality for localized joint and soft tissue wound healing are widely corroborated. The LEDs-based exposure system was designed and constructed to irradiate the selected cancer and normal cells and evaluate the biological effects induced by light exposures in visible and infrared light range. In this study, human breast cancer (MCF7 cells and human epidermal melanocytes (HEM cells (control were exposed to selected far infrared light (3400nm, 3600nm, 3800nm, 3900nm, 4100nm and 4300nm and visible and near infrared wavelengths (466nm, 585nm, 626nm, 810nm, 850nm and 950nm. The optical intensities of LEDs used for exposures were in the range of 15µW to 30µW. Cellular morphological changes of exposed and sham-exposed cells were evaluated using light microscopy. The cytotoxic effects of these low intensity light exposures on human cancer and normal cell lines were quantitatively determined by Lactate dehydrogenase (LDH cytotoxic activity and PrestoBlueTM cell viability assays. Findings reveal that far-infrared exposures were able to reduce cell viability of MCF7 cells as measured by increased LDH release activity and PrestoBlueTM assays. Further investigation of the effects of light irradiation on different types of cancer cells, study of possible signaling pathways affected by electromagnetic radiation (EMR and in vivo experimentation are required in order to draw a firm conclusion about the efficacy of low intensity light as an alternative non-invasive cancer treatment.

Threshold effect under nonlinear limitation of the intensity of high-power light

International Nuclear Information System (INIS)

Tereshchenko, S A; Podgaetskii, V M; Gerasimenko, A Yu; Savel'ev, M S

2015-01-01

A model is proposed to describe the properties of limiters of high-power laser radiation, which takes into account the threshold character of nonlinear interaction of radiation with the working medium of the limiter. The generally accepted non-threshold model is a particular case of the threshold model if the threshold radiation intensity is zero. Experimental z-scan data are used to determine the nonlinear optical characteristics of media with carbon nanotubes, polymethine and pyran dyes, zinc selenide, porphyrin-graphene and fullerene-graphene. A threshold effect of nonlinear interaction between laser radiation and some of investigated working media of limiters is revealed. It is shown that the threshold model more adequately describes experimental z-scan data. (nonlinear optical phenomena)

High intensive short laser pulse interaction with submicron clusters media

International Nuclear Information System (INIS)

Faenov, A. Ya

2008-01-01

The interaction of short intense laser pulses with structured targets, such as clusters, exhibits unique features, stemming from the enhanced absorption of the incident laser light compared to solid targets. Due to the increased absorption, these targets are heated significantly, leading to enhanced emission of x rays in the keV range and generation of electrons and multiple charged ions with kinetic energies from tens of keV to tens of MeV. Possible applications of these targets can be an electron/ion source for a table top accelerator, a neutron source for a material damage study, or an x ray source for microscopy or lithography. The overview of recent results, obtained by the high intensive short laser pulse interaction with different submicron clusters media will be presented. High resolution K and L shell spectra of plasma generated by superintense laser irradiation of micron sized Ar, Kr and Xe clusters have been measured with intensity 10"17"-10"19"W/cm"2"and a pulse duration of 30-1000fs. It is found that hot electrons produced by high contrast laser pulses allow the isochoric heating of clusters and shift the ion balance toward the higher charge states, which enhances both the X ray line yield and the ion kinetic energy. Irradiation of clusters, produced from such gas mixture, by a fs Ti:Sa laser pulses allows to enhance the soft X ray radiation of Heβ(665.7eV)and Lyα(653.7eV)of Oxygen in 2-8 times compare with the case of using as targets pure CO"2"or N"2"O clusters and reach values 2.8x10"10"(∼3μJ)and 2.7x10"10"(∼2.9μJ)ph/(sr·pulse), respectively. Nanostructure conventional soft X ray images of 100nm thick Mo and Zr foils in a wide field of view (cm"2"scale)with high spatial resolution (700nm)are obtained using the LiF crystals as soft X ray imaging detectors. When the target used for the ion acceleration studies consists of solid density clusters embedded into the background gas, its irradiation by high intensity laser light makes the target

Influence of light intensity on the toxicity of atrazine to the submerged freshwater aquatic macrophyte Elodea canadensis.

Science.gov (United States)

Brain, Richard A; Hoberg, James; Hosmer, Alan J; Wall, Steven B

2012-05-01

Light intensity can have a profound influence on the degree of phytotoxicity experienced by plants exposed to photosystem II (PSII) inhibiting herbicides. This relationship was evaluated in the submerged aquatic macrophyte Elodea canadensis exposed to three different concentrations of atrazine (510, 1000 and 2000 μg a.i./L) plus an untreated control at three different light intensities (0, 500 and 6000 lx) under static-renewal conditions for 14 days. Under 500 lx light intensity, control plants demonstrated a rapid increase in shoot length but minimal increase in dry shoot weight, suggesting limited photosynthesis. Based on shoot-length and biomass, growth was not affected by any atrazine exposure relative to controls under dark conditions (0 lx). Under low-light conditions at 500 lx, exposures to 510, 1000 and 2000 μg a.i./L atrazine significantly decreased net shoot lengths by 34%, 38% and 35%, respectively, relative to corresponding (500 lx) controls. However, atrazine exposure under this light condition did not significantly decrease biomass (dry shoot weight). Compared to 6000 lx, only approximately 8% of photosynthetically active radiation (PAR) was measured under 500 lx intensity, indicating that minimal PAR was available for photosynthesis. Under optimal light conditions (6000 lx), net shoot lengths significantly decreased in the treated atrazine groups by 48%, 51% and 68%, and net dry shoot weights (biomass) were significantly decreased by 79%, 81% and 91%, respectively, relative to corresponding (6000 lx) controls. These data show that under low light conditions, atrazine-induced effects on dry shoot weight (biomass) are dependent on available PAR and active photosynthesis. Copyright © 2011 Elsevier Inc. All rights reserved.

Light history modulates antioxidant and photosynthetic responses of biofilms to both natural (light) and chemical (herbicides) stressors.

Science.gov (United States)

Bonnineau, Chloé; Sague, Irene Gallardo; Urrea, Gemma; Guasch, Helena

2012-05-01

In multiple stress situations, the co-occurrence of environmental and chemical factors can influence organisms' ability to cope with toxicity. In this context, the influence of light adaptation on the response of freshwater biofilms to sudden light changes or to herbicides exposure was investigated by determining various parameters: diatom community composition, photosynthetic parameters, chlorophyll a content, antioxidant enzyme activities. Biofilms were grown in microcosms under sub-optimal, saturating, and high light intensities and showed already described characteristics of shade/light adaptation (community structure, photosynthetic adaptation, etc.). Light history modulated antioxidant and photosynthetic responses of biofilms to the stress caused by short-term exposure to sudden light changes or to herbicides. First biofilms adapted to sub-optimal light intensity (shade-adapted) were found to be more sensitive to an increase in light intensity than high-light adapted ones to a reduction in light intensity. Second, while light history influenced biofilms' response to glyphosate, it had little influence on biofilms' response to copper and none on its response to oxyfluorfen. Indeed glyphosate exposure led to a stronger decrease in photosynthetic efficiency of shade-adapted biofilms (EC(50) = 11.7 mg L(-1)) than of high-light adapted communities (EC(50) = 35.6 mg L(-1)). Copper exposure led to an activation of ascorbate peroxidase (APX) in biofilms adapted to sub-optimal and saturating light intensity while the protein content decreased in all biofilms exposed to copper. Oxyfluorfen toxicity was independent of light history provoking an increase in APX activity. In conclusion this study showed that both previous exposure to contaminants and physical habitat characteristics might influence community tolerance to disturbances strongly.

High Intensity Exercise in Multiple Sclerosis

DEFF Research Database (Denmark)

Wens, Inez; Dalgas, Ulrik; Vandenabeele, Frank

2015-01-01

Introduction Low-to-moderate intensity exercise improves muscle contractile properties and endurance capacity in multiple sclerosis (MS). The impact of high intensity exercise remains unknown. Methods Thirty-four MS patients were randomized into a sedentary control group (SED, n = 11) and 2...... exercise groups that performed 12 weeks of a high intensity interval (HITR, n = 12) or high intensity continuous cardiovascular training (HCTR, n = 11), both in combination with resistance training. M.vastus lateralis fiber cross sectional area (CSA) and proportion, knee-flexor/extensor strength, body...... composition, maximal endurance capacity and self-reported physical activity levels were assessed before and after 12 weeks. Results Compared to SED, 12 weeks of high intensity exercise increased mean fiber CSA (HITR: +21±7%, HCTR: +23±5%). Furthermore, fiber type I CSA increased in HCTR (+29±6%), whereas type...

[Suppression of visceral pain by action of the low intensity polarized light on acupuncture antinociceptive points].

Science.gov (United States)

Lymans'kyĭ, Iu P; Tamarova, Z A; Huliar, S O

2003-01-01

In experiments on mice, statistically authentic weakening of visceral pain has been shown after an action of low intensity polarized light from a device Bioptron on antinociceptive acupuncture points (AP). Pain was caused by an intraperitoneal injection of 2% acetic acid (0.1 ml/10 g). The intensity of pain was judged on duration and frequency of painful behavioral reactions (writhing, licking of abdomen), as well as on duration of sleep, eating and motor activity. In animals which immediately after injections of acetic acid were exposed to polarized light of low intensity for 10 min, applied on any of antinociceptive APs (E-36, E-43, VC-8, RP-6), the duration of painful behavioral reaction was determined to be reduced, while that of non-painful one increased. The comparison of the total duration of the writhing at control and experimental mice showed that an activation of AP E-43 induced the greatest analgesic effect (76.5%), from AP VC-8 it was 76.3%, from RP-6--46.8%, and from E-36--41.4%. We have concluded that the effect of polarized light of low intensity on APs was a convenient non-pharmacological method of treating visceral pain.

Integration of a high-NA light microscope in a scanning electron microscope.

Science.gov (United States)

Zonnevylle, A C; Van Tol, R F C; Liv, N; Narvaez, A C; Effting, A P J; Kruit, P; Hoogenboom, J P

2013-10-01

We present an integrated light-electron microscope in which an inverted high-NA objective lens is positioned inside a scanning electron microscope (SEM). The SEM objective lens and the light objective lens have a common axis and focal plane, allowing high-resolution optical microscopy and scanning electron microscopy on the same area of a sample simultaneously. Components for light illumination and detection can be mounted outside the vacuum, enabling flexibility in the construction of the light microscope. The light objective lens can be positioned underneath the SEM objective lens during operation for sub-10 μm alignment of the fields of view of the light and electron microscopes. We demonstrate in situ epifluorescence microscopy in the SEM with a numerical aperture of 1.4 using vacuum-compatible immersion oil. For a 40-nm-diameter fluorescent polymer nanoparticle, an intensity profile with a FWHM of 380 nm is measured whereas the SEM performance is uncompromised. The integrated instrument may offer new possibilities for correlative light and electron microscopy in the life sciences as well as in physics and chemistry. © 2013 The Authors Journal of Microscopy © 2013 Royal Microscopical Society.

Effect of intense pulsed light on immature burn scars: A clinical study

Directory of Open Access Journals (Sweden)

Arindam Sarkar

2014-01-01

Full Text Available Introduction: As intense pulsed light (IPL is widely used to treat cutaneous vascular malformations and also used as non-ablative skin rejunuvation to remodel the skin collagen. A study has been undertaken to gauze the effect of IPL on immature burn scars with regard to vascularity, pliability and height. Materials and Methods: This study was conducted between June 2013 and May 2014, among patients with immature burn scars that healed conservatively within 2 months. Photographic evidence of appearance of scars and grading and rating was done with Vancouver Scar Scale parameters. Ratings were done for both case and control scar after the completion of four IPL treatment sessions and were compared. Results: Out of the 19 cases, vascularity, pliability and height improved significantly (P < 0.05 in 13, 14 and 11 scars respectively following IPL treatment. Conclusions: Intense pulsed light was well-tolerated by patients, caused good improvement in terms of vascularity, pliability, and height of immature burn scar.

Discussion of superconducting and room-temperature high-intensity ion linacs

International Nuclear Information System (INIS)

Jameson, R.A.

1996-01-01

The point of view taken in this discussion is that the basic technology base exists in all essential respects for both superconducting or room-temperature rf linac accelerators and associated power and control systems, and thus a project can make a choice between these technologies on overall system considerations. These include performance, cost, availability, flexibility, and upgradability. Large high-intensity neutron source proposals involving light-ion rf linacs in three categories are reviewed in this context. The categories arc cw linacs to high (∼1 GeV) and low (∼40 MeV) output energy, and pulsed linacs to energy ∼1 GeV

Invasive submerged freshwater macrophytes are more plastic in their response to light intensity than to the availability of free CO2 in air-equilibrated water

DEFF Research Database (Denmark)

Eller, Franziska; Alnoee, Anette B.; Boderskov, Teis

2015-01-01

1. The future increase in the atmospheric CO2 concentration is likely to affect the growth and performance of submerged freshwater macrophytes because of higher concentrations of free CO2 in the water at air equilibrium. We measured the plastic responses to free CO2 and light for several traits...... in all four species. 4. As the growth and photosynthesis of the four invasive bicarbonate users were only slightly affected by the CO2 availability in air-equilibrated water, the future rise in atmospheric CO2 is unlikely to exacerbate their invasive behaviour and may even reduce their competitiveness...... compensation point, and with higher concentrations of photosynthetic pigments and quantum yield. The bicarbonate uptake capacity was generally highest at the high light intensity and high concentrations of free CO2. Plasticity indices for light intensity were consistently higher than for CO2 availability...

Effects of Light Intensity on Development and Chlorophyll Content in the Arabidopsis Mutant Plants with Defects in Photosynthesis

Directory of Open Access Journals (Sweden)

E.Yu. Garnik

2015-12-01

Full Text Available The developmental stages and adaptability to different light intensity (150 µmol*m-2*s-1 and 100 µmol*m-2*s-1 in Arabidopsis mutant lines with defects of photosynthetic apparatus were analyzed. Plant development in the mutant lines depended on the light intensity to varying degrees. Lines ch1-1 (lack of the chlorophyllide a oxygenase and rtn16 (decreased chlorophyll a and b amounts were the most susceptible to the light decrease. No one of the investigated lines demonstrated chlorophyll a/b rate alteration under the different light conditions. The depleted chlorophyll content has had the major effect on the mutant plants development under the different light conditions. The different chlorophyll a/b rate correlated with the different adaptability of mutant plants to low light.

Roll-to-roll-compatible, flexible, transparent electrodes based on self-nanoembedded Cu nanowires using intense pulsed light irradiation

Science.gov (United States)

Zhong, Zhaoyang; Woo, Kyoohee; Kim, Inhyuk; Hwang, Hyewon; Kwon, Sin; Choi, Young-Man; Lee, Youngu; Lee, Taik-Min; Kim, Kwangyoung; Moon, Jooho

2016-04-01

Copper nanowire (Cu NW)-based flexible transparent conductive electrodes (FTCEs) have been investigated in detail for use in various applications such as flexible touch screens, organic photovoltaics and organic light-emitting diodes. In this study, hexadecylamine (HDA) adsorbed onto the surface of NWs is changed into polyvinylpyrrolidone (PVP) via a ligand exchange process; the high-molecular-weight PVP enables high dispersion stability. Intense pulsed light (IPL) irradiation is used to remove organic species present on the surface of the NWs and to form direct connections between the NWs rapidly without any atmospheric control. NWs are self-nanoembedded into a plastic substrate after IPL irradiation, which results in a smooth surface, strong NW/substrate adhesion, excellent mechanical flexibility and enhanced oxidation stability. Moreover, Cu NW FTCEs with high uniformities are successfully fabricated on a large area (150 mm × 200 mm) via successive IPL irradiation that is synchronized with the motion of the sample stage. This study demonstrates the possibility of roll-to-roll-based, large-scale production of low-cost, high-performance Cu NW-based FTCEs.Copper nanowire (Cu NW)-based flexible transparent conductive electrodes (FTCEs) have been investigated in detail for use in various applications such as flexible touch screens, organic photovoltaics and organic light-emitting diodes. In this study, hexadecylamine (HDA) adsorbed onto the surface of NWs is changed into polyvinylpyrrolidone (PVP) via a ligand exchange process; the high-molecular-weight PVP enables high dispersion stability. Intense pulsed light (IPL) irradiation is used to remove organic species present on the surface of the NWs and to form direct connections between the NWs rapidly without any atmospheric control. NWs are self-nanoembedded into a plastic substrate after IPL irradiation, which results in a smooth surface, strong NW/substrate adhesion, excellent mechanical flexibility and enhanced

Control and Driving Methods for LED Based Intelligent Light Sources

OpenAIRE

Beczkowski, Szymon

2012-01-01

High power light-emitting diodes allow the creation of luminaires capable of generating saturated colour light at very high efficacies. Contrary to traditional light sources like incandescent and high-intensity discharge lamps, where colour is generated using filters, LEDs use additive light mixing, where the intensity of each primary colour diode has to be adjusted to the needed intensity to generate specified colour. The function of LED driver is to supply the diode with power needed to ach...

Lighting, sleep and circadian rhythm: An intervention study in the intensive care unit.

Science.gov (United States)

Engwall, Marie; Fridh, Isabell; Johansson, Lotta; Bergbom, Ingegerd; Lindahl, Berit

2015-12-01

Patients in an intensive care unit (ICU) may risk disruption of their circadian rhythm. In an intervention research project a cycled lighting system was set up in an ICU room to support patients' circadian rhythm. Part I aimed to compare experiences of the lighting environment in two rooms with different lighting environments by lighting experiences questionnaire. The results indicated differences in advantage for the patients in the intervention room (n=48), in perception of daytime brightness (p=0.004). In nighttime, greater lighting variation (p=0.005) was found in the ordinary room (n=52). Part II aimed to describe experiences of lighting in the room equipped with the cycled lighting environment. Patients (n=19) were interviewed and the results were presented in categories: "A dynamic lighting environment", "Impact of lighting on patients' sleep", "The impact of lighting/lights on circadian rhythm" and "The lighting calms". Most had experiences from sleep disorders and half had nightmares/sights and circadian rhythm disruption. Nearly all were pleased with the cycled lighting environment, which together with daylight supported their circadian rhythm. In night's actual lighting levels helped patients and staff to connect which engendered feelings of calm. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Influence of Different Light Sources, Illumination Intensities and Storage Times on the Vitamin C Content in Pasteurized Milk

OpenAIRE

ÇAKMAKÇI, Songül; TURGUT, Tamer

2005-01-01

The effect of various light sources and illumination intensities on the destruction of vitamin C was determined during the storage of pasteurized milk. For this purpose, raw cow's milk was pasteurized at 72 oC for 15 s, and then stored in 2 different refrigerators (4 ± 1oC) illuminated by fluorescent and tungsten light (normal light) sources with intensities of 1100, 2400 and 5800 lux. As a control group, a pasteurized milk sample was stored at the same temperature under dark conditi...

Flight control and landing precision in the nocturnal bee Megalopta is robust to large changes in light intensity.

Science.gov (United States)

Baird, Emily; Fernandez, Diana C; Wcislo, William T; Warrant, Eric J

2015-01-01

Like their diurnal relatives, Megalopta genalis use visual information to control flight. Unlike their diurnal relatives, however, they do this at extremely low light intensities. Although Megalopta has developed optical specializations to increase visual sensitivity, theoretical studies suggest that this enhanced sensitivity does not enable them to capture enough light to use visual information to reliably control flight in the rainforest at night. It has been proposed that Megalopta gain extra sensitivity by summing visual information over time. While enhancing the reliability of vision, this strategy would decrease the accuracy with which they can detect image motion-a crucial cue for flight control. Here, we test this temporal summation hypothesis by investigating how Megalopta's flight control and landing precision is affected by light intensity and compare our findings with the results of similar experiments performed on the diurnal bumblebee Bombus terrestris, to explore the extent to which Megalopta's adaptations to dim light affect their precision. We find that, unlike Bombus, light intensity does not affect flight and landing precision in Megalopta. Overall, we find little evidence that Megalopta uses a temporal summation strategy in dim light, while we find strong support for the use of this strategy in Bombus.

Strategy Guideline: High Performance Residential Lighting

Energy Technology Data Exchange (ETDEWEB)

Holton, J.

2012-02-01

The Strategy Guideline: High Performance Residential Lighting has been developed to provide a tool for the understanding and application of high performance lighting in the home. The high performance lighting strategies featured in this guide are drawn from recent advances in commercial lighting for application to typical spaces found in residential buildings. This guide offers strategies to greatly reduce lighting energy use through the application of high quality fluorescent and light emitting diode (LED) technologies. It is important to note that these strategies not only save energy in the home but also serve to satisfy the homeowner's expectations for high quality lighting.

Lighting intensity of the soilsurface and restocking of oak groves

Science.gov (United States)

Slepykh, Victor; Zubko, Anna; Povolotckaia, Nina

2016-04-01

Oak groves of Caucasian Mineral Vody region (CMVR) possess a high ecological and balneological potential which defines the significance of their preservation and reproduction [1]. The role assessment of lighting intensity on renewal of oak groves was carried out on four trial squares (ts) in natural sixty-seven years old forest stand with prevalence of English oak (Quercus robur L.) with unimodal sity (type of the habitat - C1). The illumination was measured at the grass level by the universal measuring instrument of meteoparameters ATT-9508 with an illumination sensor of ATA-1591. The assessment of reforestation was carried out according to the established standards [2]. In the winter of 2005 there was conducted a selecting cutting cabin of the forest stand according to a local method on ts2 with intensity 30%, on ts4 - 50% after which the illumination on the soil surface in relation to illumination of an open place in the summer of 2005 increased from 4.9% to 33.9% on ts2, and from 5.9% to 24.4% on ts4. But by 2014 the illumination decreased till 3.0% on ts2, till 5.4% on ts4 because of an intensive soil grassing down. The control was carried out by ts1 and ts3 on which from 2005 to 2014 the illumination of the soil surface decreased from 4 to 2% as a result of the development of all storeys. As a result due to an intensive soil grassing-down, the total quantity of young oak trees decreased from 2005 to 2014 from 25.6 thousand pcs/ha to 5.9 thousand pcs/ha on ts2; on from 17.3 thousand pcs/ha to 4.0 thousand pcs/ha on ts4. At the same time the total quantity of young oak trees on control squares increased respectively for 1.4% (from 18.8 thousand pcs/ha to 19.1 thousand pcs/ha) on ts1, for 38.7% (from 25.2 thousand pcs/ha to 41.1 thousand pcs/ha). The experiment showed that small young oak trees perishes in the first years of their life from a lack of light and competition from grasland vegetation without providing successful reforestation. Conclusion. So it is

Influence of light intensity and spectral composition of artificial light at night on melatonin rhythm and mRNA expression of gonadotropins in roach Rutilus rutilus.

Science.gov (United States)

Brüning, Anika; Hölker, Franz; Franke, Steffen; Kleiner, Wibke; Kloas, Werner

2018-02-01

In this study we investigated the influence of artificial light at night (ALAN) of different intensities (0, 1, 10, 100 lx) and different colours (blue, green, red) on the daily melatonin rhythm and mRNA expression of gonadotropins in roach Rutilus rutilus, a ubiquitous cyprinid, which occur in standing and moderately flowing freshwater habitats of central Europe. Melatonin concentrations were significantly lowered under nocturnal white light already at 1 lx. Low intensity blue, green and red ALAN lowered the melatonin levels significantly in comparison to a dark control. We conclude that ALAN can disturb melatonin rhythms in roach at very low intensities and at different wavelengths and thus light pollution in urban waters has the potential to impact biological rhythms in fish. However, mRNA expression of gonadotropins was not affected by ALAN during the period of the experiments. Thus, suspected implications of ALAN on reproduction of roach could not be substantiated.

Relativistic electron mirrors from high intensity laser nanofoil interactions

International Nuclear Information System (INIS)

Kiefer, Daniel

2012-01-01

The reflection of a laser pulse from a mirror moving close to the speed of light could in principle create an X-ray pulse with unprecedented high brightness owing to the increase in photon energy and accompanying temporal compression by a factor of 4γ 2 , where γ is the Lorentz factor of the mirror. While this scheme is theoretically intriguingly simple and was first discussed by A. Einstein more than a century ago, the generation of a relativistic structure which acts as a mirror is demanding in many different aspects. Recently, the interaction of a high intensity laser pulse with a nanometer thin foil has raised great interest as it promises the creation of a dense, attosecond short, relativistic electron bunch capable of forming a mirror structure that scatters counter-propagating light coherently and shifts its frequency to higher photon energies. However, so far, this novel concept has been discussed only in theoretical studies using highly idealized interaction parameters. This thesis investigates the generation of a relativistic electron mirror from a nanometer foil with current state-of-the-art high intensity laser pulses and demonstrates for the first time the reflection from those structures in an experiment. To achieve this result, the electron acceleration from high intensity laser nanometer foil interactions was studied in a series of experiments using three inherently different high power laser systems and free-standing foils as thin as 3nm. A drastic increase in the electron energies was observed when reducing the target thickness from the micrometer to the nanometer scale. Quasi-monoenergetic electron beams were measured for the first time from ultrathin (≤5nm) foils, reaching energies up to ∝35MeV. The acceleration process was studied in simulations well-adapted to the experiments, indicating the transition from plasma to free electron dynamics as the target thickness is reduced to the few nanometer range. The experience gained from those

Productivity of duckweed (Lemna minor as alternative forage feed for livestock in different light intensities

Directory of Open Access Journals (Sweden)

Uti Nopriani

2015-12-01

Full Text Available Duckweed (Lemna minor is a small aquatic plant that grow and float in water and spread extensively. Lemna minor is potential as a source of high quality forage. This study aimed to determine optimal light intensity on Lemna minor to generate maximum productivity. Parameters observed were physical-biological and chemical characteristics of the media (pH value, temperature, cover area, decreased of media volume, BOD, COD, nitrate, nitrite and phosphate, plant growth acceleration (number of shoots, leaf diameter and chlorophyll-a, biomass production, doubling time of cover area and the number of daughters. This study was done based on a completely randomized design with 4 levels of shading. While treatment was: without shading, shading 30%, shading 50% and shading 70% using paranet shade. Each treatment consisted of 4 replications. Result showed that the productivity of Lemna minor included the number of daughters, chlorophyll-a, biomass production, cover area, absorbed phosphate and doubling time the number of daughters reached the highest level without shading treatment (1007,21-2813,57 lux. The decrease of intensity of light, the increase the diameter of leaf. Decrease of media volume was positively correlated to size of cover area. Biomass production influenced by a wide doubling time of cover area and number of daughters.

The effect of intense light pulses on the sensory quality and instrumental color of meat from different animal breeds

OpenAIRE

Tomašević I.

2015-01-01

Intense light pulses (ILP) are an emerging processing technology, which has a potential to decontaminate food products. The light generated by ILP lamps consists of a continuum broadband spectrum from deep UV to the infrared, especially rich in UV range below 400 nm, which is germicidal. Evaluation of the effect of intense light pulses (ILP) on sensory quality of meat, game and poultry was performed using two kinds of red meat (beef and pork), two kinds of ...

Proton probing of ultra-thin foil dynamics in high intensity regime

Science.gov (United States)

Prasad, Rajendra; Aktan, Esin; Aurand, Bastian; Cerchez, Mirela; Willi, Oswald

2017-10-01

The field of laser driven ion acceleration has been enriched significantly over the past decade, thanks to the advanced laser technologies. Already, from 100s TW class systems, laser driven sources of particles and radiations are being considered in number of potential applications in science and medicine due to their unique properties. New physical effects unearthed at these systems may help understand and conduct successful experiments at several PW class multi-beam facilities with high rep rate systems, e.g. ELI. Here we present the first experimental results on ultra-thin foil dynamics irradiated by an ultra-high intensity (1020 W/cm2) , ultra-high contrast (10-12) laser pulse at ARCTURUS laser facility at HHU Duesseldorf. By employing the elegant proton probing technique it is observed that for the circular polarization of laser light, a 100nm thin target is pushed forward as a compressed layer due to the radiation pressure of light. Whereas, the linear polarization seems to decompress the target drastically. 2D particle-in-cell simulations corroborate the experimental findings. Our results confirm the previous simulation studies investigating the fundamental role played by light polarization, finite focus spot size effect and eventually electron heating including the oblique incidence at the target edges.

Unconventional use of intense pulsed light.

Science.gov (United States)

Piccolo, D; Di Marcantonio, D; Crisman, G; Cannarozzo, G; Sannino, M; Chiricozzi, A; Chimenti, S

2014-01-01

According to the literature, intense pulsed light (IPL) represents a versatile tool in the treatment of some dermatological conditions (i.e., pigmentation disorders, hair removal, and acne), due to its wide range of wavelengths. The authors herein report on 58 unconventional but effective uses of IPL in several cutaneous diseases, such as rosacea (10 cases), port-wine stain (PWS) (10 cases), disseminated porokeratosis (10 cases), pilonidal cyst (3 cases), seborrheic keratosis (10 cases), hypertrophic scar (5 cases) and keloid scar (5 cases), Becker's nevus (2 cases), hidradenitis suppurativa (2 cases), and sarcoidosis (1 case). Our results should suggest that IPL could represent a valid therapeutic support and option by providing excellent outcomes and low side effects, even though it should be underlined that the use and the effectiveness of IPL are strongly related to the operator's experience (acquired by attempting at least one specific course on the use of IPL and one-year experience in a specialized centre). Moreover, the daily use of these devices will surely increase clinical experience and provide new information, thus enhancing long-term results and improving IPL effectiveness.

Highly efficient green light harvesting from Mg doped ZnO nanoparticles: Structural and optical studies

Energy Technology Data Exchange (ETDEWEB)

Sharma, Sarla, E-mail: mail2sarlasharma@gmail.com [Department of Physics, University of Rajasthan, Jaipur 302055 (India); Vyas, Rishi [Department of Physics, Malaviya National Institute of Technology, Jaipur 302017 (India); Sharma, Neha [Department of Physics, University of Rajasthan, Jaipur 302055 (India); Singh, Vidyadhar [Okinawa Institute of Science and Technology, Graduate University, Okinawa 9040495 (Japan); Singh, Arvind [Department of Physics, Institute of Chemical Technology, Mumbai 400 019 (India); Kataria, Vanjula; Gupta, Bipin Kumar [National Physical Laboratory (CSIR), New Delhi 110012 (India); Vijay, Y.K. [Department of Physics, University of Rajasthan, Jaipur 302055 (India)

2013-03-05

Graphical abstract: Demonstration of highly efficient green light emission harvesting from Mg doped ZnO nanoparticles were synthesized via facile wet chemical route with an average particle size ∼15 nm. The resulted nanoparticles exhibit intense green emission peaking at 530 nm upon 325 nm excitation. The photoluminescence (PL) intensity of visible emission depends upon the doping concentration of Mg. The PL intensity was found maximum up to 4% doping of Mg and beyond it exhibits a decrees in emission. The obtained highly luminescent green emission of ZnO nanoparticle would be an ultimate choice for next generation optoelectronics device materials. Highlights: ► Zn{sub 1−x}Mg{sub x}O nanoparticles were prepared by mechanochemical processing. ► High blue emission intensity was observed contrary to previous reports. ► Blue emission is suggested to be originating from the high density of defects. ► Defect density in as-milled condition is very high resulting in high emission. ► Mg promoted non-radiative recombination and lowered intensities. -- Abstract: Highly efficient green light emission was observed from Mg doped ZnO nanoparticles synthesized via facile wet chemical route with an average particle size ∼15 nm. The XRD analysis confirmed the growth of wurtzite phase of ZnO nanoparticles. Moreover, the optical properties of these nanoparticles were investigated by different spectroscopic techniques. The resulted nanoparticles exhibit intense green emission peaking at 530 nm (2.34 eV) upon 325 nm (3.81 eV) excitation. The photoluminescence (PL) intensity of visible emission depends upon the doping concentration of Mg. The PL intensity was found maximum up to 4% doping of Mg, and beyond it exhibits a decrees in emission. Furthermore, by varying the band gap from 3.50 to 3.61 eV, the PL spectra showed a near band edge (NBE) emission at wavelength around 370 nm (3.35 eV) and a broad deep level emission in the visible region. The obtained highly

Position Detection Based on Intensities of Reflected Infrared Light

DEFF Research Database (Denmark)

Christensen, Henrik Vie

measurements of reflected light intensities, and includes easy calibration. The method for reconstructing 3D positions has been implemented in a prototype of a “non-Touch Screen” for a computer, so that the user can control a cursor in three dimensions by moving his/hers hand in front of the computer screen....... The 2D position reconstruction method is mplemented in a prototype of a human-machine interface (HMI) for an electrically powered wheelchair, such that the wheelchair user can control the movement of the wheelchair by head movements. Both “non-Touch Screen” prototype and wheelchair HMI has been tested...

Influence of Two Different Light Intensities from 16:00 to 20:30 Hours on Evening Dressing Behavior in the Cold

OpenAIRE

Kim, Hee-Eun; Tokura, Hiromi

2007-01-01

The present experiment tested our hypothesis that the subjects will wear more clothing in the evening cold under the influence of bright light exposure in the late afternoon and evening. Nine young female adults participated in this study. Light intensity was controlled from 9:00 h to 16:00 h at 100 lx, and from 16:00 h to 20:30 h either at 3000 lx in the bright light (»Bright«) or at 10 lx in the dim light (»Dim«) conditions. Light intensity was maintained at 10 lx from 20:30 h to ...

Ca²⁺ signal contributing to the synthesis and emission of monoterpenes regulated by light intensity in Lilium 'siberia'.

Science.gov (United States)

Hu, Zenghui; Li, Tianjiao; Zheng, Jian; Yang, Kai; He, Xiangfeng; Leng, Pingsheng

2015-06-01

The floral scent is an important part of plant volatile compounds, and is influenced by environmental factors. The emission of monoterpenes of Lilium 'siberia' is regulated by light intensity, but the mechanism is large unknown. In this study, the expression of Li-mTPS, a monoterpene synthase gene in the tepals of Lilium 'siberia', and net Ca(2+) flux were investigated after exposure to different levels of light intensity (0, 100, 300, 600, 1000, and 1500 μmol m(-2) s(-1)). Moreover the effect of LaCl3 and ethylene glycol-bis-(2-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA) on the Li-mTPS expression, monoterpene emission, and net Ca(2+) flux were examined at 600 μmol m(-2) s(-1). The results showed that along with the enhancement of light intensity, the expression level of Li-mTPS increased gradually, and the net Ca(2+) influx was also enhanced showing a similar pattern. It was found that LaCl3 and EGTA effectively inhibited the increase in expression of Li-mTPS and the net Ca(2+) influx induced by light treatment. Moreover, the release amounts of monoterpenes decreased significantly after treatment with LaCl3 and EGTA. So it can be concluded that Ca(2+) signal contributed to the biosynthesis and emission of monoterpenes regulated by light intensity in Lilium 'siberia' tepals. The increased light intensity firstly triggered the Ca(2+) influx to cytoplasm, and then the gene expression of monoterpene synthases downstream was activated to regulate the biosynthesis and emission of monoterpenes. But in the signaling pathway other mechanisms were thought to be involved in the emission of monoterpenes regulated by light intensity, which need to be investigated in future research. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Flight control and landing precision in the nocturnal bee Megalopta is robust to large changes in light intensity

Directory of Open Access Journals (Sweden)

Emily eBaird

2015-10-01

Full Text Available Like its diurnal relatives, Megalopta genalis use visual information to control flight. Unlike their diurnal relatives, however, they do this at extremely low light intensities. Although Megalopta has developed optical specialisations to increase visual sensitivity, theoretical studies suggest that this enhanced sensitivity does not enable them to capture enough light to use visual information to reliably control flight in the rainforest at night. It has been proposed that Megalopta gain extra sensitivity by summing visual information over time. While enhancing the reliability of vision, this strategy would decrease the accuracy with which they can detect image motion - a crucial cue for flight control. Here, we test this temporal summation hypothesis by investigating how Megalopta’s flight control and landing precision is affected by light intensity and compare our findings with the results of similar experiments performed on the diurnal bumblebee Bombus terrestris, to explore the extent to which Megalopta’s adaptations to dim light affect their precision. We find that, unlike Bombus, light intensity does not affect flight and landing precision in Megalopta. Overall, we find little evidence that Megalopta uses a temporal summation strategy in dim light, while we find strong support for the use of this strategy in Bombus.

Numerical investigation of symmetry breaking and critical behavior of the acoustic streaming field in high-intensity discharge lamps

International Nuclear Information System (INIS)

Baumann, Bernd; Schwieger, Joerg; Wolff, Marcus; Manders, Freddy; Suijker, Jos

2015-01-01

For energy efficiency and material cost reduction it is preferred to drive high-intensity discharge lamps at frequencies of approximately 300 kHz. However, operating lamps at these high frequencies bears the risk of stimulating acoustic resonances inside the arc tube, which can result in low frequency light flicker and even lamp destruction. The acoustic streaming effect has been identified as the link between high frequency resonances and low frequency flicker. A highly coupled three-dimensional multiphysics model has been set up to calculate the acoustic streaming velocity field inside the arc tube of high-intensity discharge lamps. It has been found that the velocity field suffers a phase transition to an asymmetrical state at a critical acoustic streaming force. In certain respects the system behaves similar to a ferromagnet near the Curie point. It is discussed how the model allows to investigate the light flicker phenomenon. Concerning computer resources the procedure is considerably less demanding than a direct approach with a transient model. (paper)

Beam Dynamics Studies for High-Intensity Beams in the CERN Proton Synchrotron

CERN Document Server

AUTHOR|(CDS)2082016; Benedikt, Michael

With the discovery of the Higgs boson, the existence of the last missing piece of the Standard Model of particle physics (SM) was confirmed. However, even though very elegant, this theory is unable to explain, for example, the generation of neutrino masses, nor does it account for dark energy or dark matter. To shed light on some of these open questions, research in fundamental particle physics pursues two complimentary approaches. On the one hand, particle colliders working at the high-energy frontier, such as the Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN), located in Geneva, Switzerland, are utilized to investigate the fundamental laws of nature. Alternatively, fixed target facilities require high-intensity beams to create a large flux of secondary particles to investigate, for example, rare particle decay processes, or to create neutrino beams. This thesis investigates limitations arising during the acceleration of high-intensity beams at the CERN Proton Synchrotro...

HYDROGEN PRODUCTION BY THE CYANOBACTERIUM PLECTONEMA BORYANUM: EFFECTS OF INITIAL NITRATE CONCENTRATION, LIGHT INTENSITY, AND INHIBITION OF PHOTOSYSTEM II BY DCMU

Energy Technology Data Exchange (ETDEWEB)

Carter, B.; Huesemann, M.

2008-01-01

The alarming rate at which atmospheric carbon dioxide levels are increasing due to the burning of fossil fuels will have incalculable consequences if disregarded. Fuel cells, a source of energy that does not add to carbon dioxide emissions, have become an important topic of study. Although signifi cant advances have been made related to fuel cells, the problem of cheap and renewable hydrogen production still remains. The cyanobacterium Plectonema boryanum has demonstrated potential as a resolution to this problem by producing hydrogen under nitrogen defi cient growing conditions. Plectonema boryanum cultures were tested in a series of experiments to determine the effects of light intensity, initial nitrate concentration, and photosystem II inhibitor DCMU (3-(3,4- dichlorophenyl)-1,1-dimethylurea) upon hydrogen production. Cultures were grown in sterile Chu. No. 10 medium within photobioreactors constantly illuminated by halogen lights. Because the enzyme responsible for hydrogen production is sensitive to oxygen, the medium was continuously sparged with argon/CO2 (99.7%/0.3% vol/vol) by gas dispersion tubes immersed in the culture. Hydrogen production was monitored by using a gas chromatograph equipped with a thermal conductivity detector. In the initial experiment, the effects of initial nitrate concentration were tested and results revealed cumulative hydrogen production was maximum at an initial nitrate concentration of 1 mM. A second experiment was then conducted at an initial nitrate concentration of 1 mM to determine the effects of light intensity at 50, 100, and 200 μmole m-2 s-1. Cumulative hydrogen production increased with increasing light intensity. A fi nal experiment, conducted at an initial nitrate concentration of 2 mM, tested the effects of high light intensity at 200 and 400 μmole m-2 s-1. Excessive light at 400 μmole m-2 s-1 decreased cumulative hydrogen production. Based upon all experiments, cumulative hydrogen production rates were optimal

Ultrabroad linewidth orange-emitting nanowires LED for high CRI laser-based white lighting and gigahertz communications

KAUST Repository

Janjua, Bilal; Ng, Tien Khee; Zhao, Chao; Oubei, Hassan M.; Shen, Chao; Prabaswara, Aditya; Alias, Mohd Sharizal; Alhamoud, Abdullah Ali; Alatawi, Abdullah Awaad; Albadri, Abdulrahman M.; Alyamani, Ahmed Y.; El-Desouki, Munir M.; Ooi, Boon S.

2016-01-01

intensity- and bandwidth-tunable for high color-quality remained unexplored. In this paper, we present for the first time, the proof-of-concept of the generation of high-quality white light using an InGaN-based orange nanowires (NWs) LED grown on silicon

High intensity hadron accelerators

International Nuclear Information System (INIS)

Teng, L.C.

1989-05-01

This rapporteur report consists mainly of two parts. Part I is an abridged review of the status of all High Intensity Hadron Accelerator projects in the world in semi-tabulated form for quick reference and comparison. Part II is a brief discussion of the salient features of the different technologies involved. The discussion is based mainly on my personal experiences and opinions, tempered, I hope, by the discussions I participated in in the various parallel sessions of the workshop. In addition, appended at the end is my evaluation and expression of the merits of high intensity hadron accelerators as research facilities for nuclear and particle physics

Testing a high-power LED based light source for hyperspectral imaging microscopy

Science.gov (United States)

Klomkaew, Phiwat; Mayes, Sam A.; Rich, Thomas C.; Leavesley, Silas J.

2017-02-01

Our lab has worked to develop high-speed hyperspectral imaging systems that scan the fluorescence excitation spectrum for biomedical imaging applications. Hyperspectral imaging can be used in remote sensing, medical imaging, reaction analysis, and other applications. Here, we describe the development of a hyperspectral imaging system that comprised an inverted Nikon Eclipse microscope, sCMOS camera, and a custom light source that utilized a series of high-power LEDs. LED selection was performed to achieve wavelengths of 350-590 nm. To reduce scattering, LEDs with low viewing angles were selected. LEDs were surface-mount soldered and powered by an RCD. We utilized 3D printed mounting brackets to assemble all circuit components. Spectraradiometric calibration was performed using a spectrometer (QE65000, Ocean Optics) and integrating sphere (FOIS-1, Ocean Optics). Optical output and LED driving current were measured over a range of illumination intensities. A normalization algorithm was used to calibrate and optimize the intensity of the light source. The highest illumination power was at 375 nm (3300 mW/cm2), while the lowest illumination power was at 515, 525, and 590 nm (5200 mW/cm2). Comparing the intensities supplied by each LED to the intensities measured at the microscope stage, we found there was a great loss in power output. Future work will focus on using two of the same LEDs to double the power and finding more LED and/or laser diodes and chips around the range. This custom hyperspectral imaging system could be used for the detection of cancer and the identification of biomolecules.

Intense ion beams for inertial confinement fusion

International Nuclear Information System (INIS)

Mehlhorn, T.A.

1997-01-01

Intense beams of light of heavy ions are being studied as inertial confinement fusion (ICF) drivers for high yield and energy. Heavy and light ions have common interests in beam transport, targets, and alternative accelerators. Self-pinched transport is being jointly studied. This article reviews the development of intense ion beams for ICF. Light-ion drivers are highlighted because they are compact, modular, efficient and low cost. Issues facing light ions are: (1) decreasing beam divergence; (2) increasing beam brightness; and (3) demonstrating self-pinched transport. Applied-B ion diodes are favored because of efficiency, beam brightness, perceived scalability, achievable focal intensity, and multistage capability. A light-ion concept addressing these issues uses: (1) an injector divergence of ≤ 24 mrad at 9 MeV; (2) two-stage acceleration to reduce divergence to ≤ 12 mrad at 35 MeV; and (3) self-pinched transport accepting divergences up to 12 mrad. Substantial progress in ion-driven target physics and repetitive ion diode technology is also presented. Z-pinch drivers are being pursued as the shortest pulsed power path to target physics experiments and high-yield fusion. However, light ions remain the pulsed power ICF driver of choice for high-yield fusion energy applications that require driver standoff and repetitive operation. 100 refs

Violation of Bloch's Law That Specifies Reciprocity of Intensity and Duration with Brief Light Flashes

Directory of Open Access Journals (Sweden)

Ernest Greene

2013-12-01

Full Text Available For more than a century researchers have been reporting that the visual impact of a very brief flash is determined by the quantity of photons that the flash delivers. This has been variously described as the Bunsen-Roscoe Law or Bloch's Law, often specified as reciprocity of intensity × duration. Prior research found no evidence for such reciprocity when microsecond-duration flashes from a light-emitting diode array were used to display the major contours of nameable shapes. The present work tested with flash durations ranging up to 100 ms and also found no reciprocity. This departure from classic principles might be due to the specific range of wavelengths of the light-emitting diodes and to a mesopic level of ambient light, which together would preclude activation of rods. The reciprocity of intensity and duration may only be valid with full dark adaptation and very dim flashes that activate rods.

Broadband white light emission from Ce:AlN ceramics: High thermal conductivity down-converters for LED and laser-driven solid state lighting

Directory of Open Access Journals (Sweden)

A. T. Wieg

2016-12-01

Full Text Available We introduce high thermal conductivity aluminum nitride (AlN as a transparent ceramic host for Ce3+, a well-known active ion dopant. We show that the Ce:AlN ceramics have overlapping photoluminescent (PL emission peaks that cover almost the entire visible range resulting in a white appearance under 375 nm excitation without the need for color mixing. The PL is due to a combination of intrinsic AlN defect complexes and Ce3+ electronic transitions. Importantly, the peak intensities can be tuned by varying the Ce concentration and processing parameters, causing different shades of white light without the need for multiple phosphors or light sources. The Commission Internationale de l’Eclairage coordinates calculated from the measured spectra confirm white light emission. In addition, we demonstrate the viability of laser driven white light emission by coupling the Ce:AlN to a readily available frequency tripled Nd-YAG laser emitting at 355 nm. The high thermal conductivity of these ceramic down-converters holds significant promise for producing higher power white light sources than those available today.

Relativistic electron mirrors from high intensity laser nanofoil interactions

Energy Technology Data Exchange (ETDEWEB)

Kiefer, Daniel

2012-12-21

The reflection of a laser pulse from a mirror moving close to the speed of light could in principle create an X-ray pulse with unprecedented high brightness owing to the increase in photon energy and accompanying temporal compression by a factor of 4γ{sup 2}, where γ is the Lorentz factor of the mirror. While this scheme is theoretically intriguingly simple and was first discussed by A. Einstein more than a century ago, the generation of a relativistic structure which acts as a mirror is demanding in many different aspects. Recently, the interaction of a high intensity laser pulse with a nanometer thin foil has raised great interest as it promises the creation of a dense, attosecond short, relativistic electron bunch capable of forming a mirror structure that scatters counter-propagating light coherently and shifts its frequency to higher photon energies. However, so far, this novel concept has been discussed only in theoretical studies using highly idealized interaction parameters. This thesis investigates the generation of a relativistic electron mirror from a nanometer foil with current state-of-the-art high intensity laser pulses and demonstrates for the first time the reflection from those structures in an experiment. To achieve this result, the electron acceleration from high intensity laser nanometer foil interactions was studied in a series of experiments using three inherently different high power laser systems and free-standing foils as thin as 3nm. A drastic increase in the electron energies was observed when reducing the target thickness from the micrometer to the nanometer scale. Quasi-monoenergetic electron beams were measured for the first time from ultrathin (≤5nm) foils, reaching energies up to ∝35MeV. The acceleration process was studied in simulations well-adapted to the experiments, indicating the transition from plasma to free electron dynamics as the target thickness is reduced to the few nanometer range. The experience gained from those

Development and evaluation of a light-emitting diode endoscopic light source

Science.gov (United States)

Clancy, Neil T.; Li, Rui; Rogers, Kevin; Driscoll, Paul; Excel, Peter; Yandle, Ron; Hanna, George; Copner, Nigel; Elson, Daniel S.

2012-03-01

Light-emitting diode (LED) based endoscopic illumination devices have been shown to have several benefits over arclamp systems. LEDs are energy-efficient, small, durable, and inexpensive, however their use in endoscopy has been limited by the difficulty in efficiently coupling enough light into the endoscopic light cable. We have demonstrated a highly homogenised lightpipe LED light source that combines the light from four Luminus LEDs emitting in the red, green, blue and violet using innovative dichroics that maximise light throughput. The light source spectrally combines light from highly divergent incoherent sources that have a Lambertian intensity profile to provide illumination matched to the acceptance numerical aperture of a liquid light guide or fibre bundle. The LED light source was coupled to a standard laparoscope and performance parameters (power, luminance, colour temperature) compared to a xenon lamp. Although the total illuminance from the endoscope was lower, adjustment of the LEDs' relative intensities enabled contrast enhancement in biological tissue imaging. The LED light engine was also evaluated in a minimally invasive surgery (MIS) box trainer and in vivo during a porcine MIS procedure where it was used to generate 'narrowband' images. Future work using the violet LED could enable photodynamic diagnosis of bladder cancer.

'J-KAREN' - high intensity, high contrast laser

International Nuclear Information System (INIS)

Kiriyama, Hiromitsu; Mori, Michiaki; Nakai, Yoshiki; Okada, Hajime; Sasao, Hajime; Sagisaka, Akito; Ochi, Yoshihiro; Tanaka, Momoko; Kondo, Kiminori; Tateno, Ryo; Sugiyama, Akira; Daido, Hiroyuki; Koike, Masato; Kawanishi, Syunichi; Shimomura, Takuya; Tanoue, Manabu; Wakai, Daisuke; Kondo, Shuji; Kanazawa, Shuhei

2010-01-01

We report on the high intensity, high contrast double chirped-pulse amplification (CPA) Ti:sapphire laser system (named J-KAREN). By use of an optical parametric chirped-pulse amplification (OPCPA) preamplifier that is seeded by a cleaned high-energy pulse, a background amplified spontaneous emission (ASE) level of 10 -10 relative to the peak main femtosecond pulse on the picosecond timescales demonstrated with an output energy of 1.7 J and a pulse duration of 30 fs, corresponding to a peak power of 60TW at a 10 Hz repetition rate. This system which uses a cryogenically-cooled Ti:sapphire final amplifier generates focused peak intensity in excess of 10 20 W/cm 2 at a 10 Hz repetition rate. (author)

Unconventional Use of Intense Pulsed Light

Directory of Open Access Journals (Sweden)

D. Piccolo

2014-01-01

Full Text Available According to the literature, intense pulsed light (IPL represents a versatile tool in the treatment of some dermatological conditions (i.e., pigmentation disorders, hair removal, and acne, due to its wide range of wavelengths. The authors herein report on 58 unconventional but effective uses of IPL in several cutaneous diseases, such as rosacea (10 cases, port-wine stain (PWS (10 cases, disseminated porokeratosis (10 cases, pilonidal cyst (3 cases, seborrheic keratosis (10 cases, hypertrophic scar (5 cases and keloid scar (5 cases, Becker’s nevus (2 cases, hidradenitis suppurativa (2 cases, and sarcoidosis (1 case. Our results should suggest that IPL could represent a valid therapeutic support and option by providing excellent outcomes and low side effects, even though it should be underlined that the use and the effectiveness of IPL are strongly related to the operator’s experience (acquired by attempting at least one specific course on the use of IPL and one-year experience in a specialized centre. Moreover, the daily use of these devices will surely increase clinical experience and provide new information, thus enhancing long-term results and improving IPL effectiveness.

System and method that suppresses intensity fluctuations for free space high-speed optical communication

Science.gov (United States)

Berman, Gennady P [Los Alamos, NM; Bishop, Alan R [Los Alamos, NM; Nguyen, Dinh C [Los Alamos, NM; Chernobrod, Boris M [Santa Fe, NM; Gorshkov, Vacheslav N [Kiev, UA

2009-10-13

A high-speed (Gbps), free space optical communication system is based on spectral encoding of radiation from a wide band light source, such as a laser. By using partially coherent laser beams in combination with a relatively slow photosensor, scintillations can be suppressed by orders of magnitude for distances of more than 10 km. To suppress the intensity fluctuations due to atmospheric turbulence, a source with partial transverse coherence in combination with slow response time photodetector is used. Information is encoded in the spectral domain of a wideband optical source by modulation of spectral amplitudes. A non-coherent light source with wide spectrum (an LED, for example) may be used for high-speed communication over short (less than about a mile) distances.

Strategy Guideline. High Performance Residential Lighting

Energy Technology Data Exchange (ETDEWEB)

Holton, J. [IBACOS, Inc., Pittsburgh, PA (United States)

2012-02-01

This report has been developed to provide a tool for the understanding and application of high performance lighting in the home. The strategies featured in this guide are drawn from recent advances in commercial lighting for application to typical spaces found in residential buildings. This guide offers strategies to greatly reduce lighting energy use through the application of high quality fluorescent and light emitting diode (LED) technologies. It is important to note that these strategies not only save energy in the home but also serve to satisfy the homeowner’s expectations for high quality lighting.

Photophoretic trampoline—Interaction of single airborne absorbing droplets with light

Science.gov (United States)

Esseling, Michael; Rose, Patrick; Alpmann, Christina; Denz, Cornelia

2012-09-01

We present the light-induced manipulation of absorbing liquid droplets in air. Ink droplets from a printer cartridge are used to demonstrate that absorbing liquids—just like their solid counterparts—can interact with regions of high light intensity due to the photophoretic force. It is shown that droplets follow a quasi-ballistic trajectory after bouncing off a high intensity light sheet. We estimate the intensities necessary for this rebound of airborne droplets and change the droplet trajectories through a variation of the manipulating light field.

Case histories of intense pulsed light phototherapy in dermatology - the HPPL™ and IFL™ technologies

Directory of Open Access Journals (Sweden)

Alessandro Martella

2017-06-01

Full Text Available The intense pulsed light (IPL and laser technologies are widely used for skin rejuvenation and for treating several dermatological disorders such as skin dyschromia and acne, and for non-ablative dermal remodeling of rhytides and hypertrophic scars. Technological evolution is rapid. The High Power Pulsed Light™ [HPPL™] and Incoherent Fast Light™ technologies [IFL™, Novavision Group S.p.A., 20826 Misinto (MB, Italy] are recent innovations in the field of IPL technologies; IFL™ is a further evolution of the already advanced HPPL™ system. The paper presents a selection of case histories of dermatological lesions treated with the HPPL™ and IFL™ technologies. All study materials were appropriately peer-reviewed for ethical problems.

Parameter study for polymer solar modules based on various cell lengths and light intensities

Energy Technology Data Exchange (ETDEWEB)

Slooff, L.H.; Burgers, A.R.; Bende, E.E.; Kroon, J.M. [ECN Solar Energy, P.O. Box 1, 1755 ZG Petten (Netherlands); Veenstra, S.C. [ECN Solar Energy, Solliance, High Tech Campus 5, P63, 5656AE Eindhoven (Netherlands)

2013-10-15

Polymer solar cells may be applied in portable electronic devices, where light intensity and spectral distribution of the illuminating source can be very different compared to outdoor applications. As the power output of solar cells depends on temperature, light intensity and spectrum, the design of the module must be optimized for the specific illumination conditions in the different applications. The interconnection area between cells in a module must be as narrow as possible to maximize the active area, also called geometrical fill factor, of the module. Laser scribing has the potential to realize this. The optimal width of the interconnection zone depends both on technological limitations, e.g. laser scribe width and the minimal distance between scribes, and electrical limitations like resistive losses. The latter depends on the generated current in the cell and thus also on illumination intensity. Besides that, also the type of junction, i.e. a single or tandem junction, will influence the optimal geometry. In this paper a calculation model is presented that can be used for electrical modeling of polymer cells and modules in order to optimize the performance for the specific illumination conditions.

High resolution measurement of light in terrestrial ecosystems using photodegrading dyes.

Directory of Open Access Journals (Sweden)

Javier Roales

Full Text Available Incoming solar radiation is the main determinant of terrestrial ecosystem processes, such as primary production, litter decomposition, or soil mineralization rates. Light in terrestrial ecosystems is spatially and temporally heterogeneous due to the interaction among sunlight angle, cloud cover and tree-canopy structure. To integrate this variability and to know light distribution over time and space, a high number of measurements are needed, but tools to do this are usually expensive and limited. An easy-to-use and inexpensive method that can be used to measure light over time and space is needed. We used two photodegrading fluorescent organic dyes, rhodamine WT (RWT and fluorescein, for the quantification of light. We measured dye photodegradation as the decrease in fluorescence across an irradiance gradient from full sunlight to deep shade. Then, we correlated it to accumulated light measured with PAR quantum sensors and obtained a model for this behavior. Rhodamine WT and fluorescein photodegradation followed an exponential decay curve with respect to accumulated light. Rhodamine WT degraded slower than fluorescein and remained unaltered after exposure to temperature changes. Under controlled conditions, fluorescence of both dyes decreased when temperatures increased, but returned to its initial values after cooling to the pre-heating temperature, indicating no degradation. RWT and fluorescein can be used to measure light under a varying range of light conditions in terrestrial ecosystems. This method is particularly useful to integrate solar radiation over time and to measure light simultaneously at different locations, and might be a better alternative to the expensive and time consuming traditional light measurement methods. The accuracy, low price and ease of this method make it a powerful tool for intensive sampling of large areas and for developing high resolution maps of light in an ecosystem.

Concept for a new high resolution high intensity diffractometer

Energy Technology Data Exchange (ETDEWEB)

Stuhr, U [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1997-09-01

A concept of a new time-of-flight powder-diffractometer for a thermal neutral beam tube at SINQ is presented. The design of the instrument optimises the contradictory conditions of high intensity and high resolution. The high intensity is achieved by using many neutron pulses simultaneously. By analysing the time-angle-pattern of the detected neutrons an assignment of the neutrons to a single pulse is possible. (author) 3 figs., tab., refs.

A comparative study of noise in supercontinuum light sources for ultra-high resolution optical coherence tomography

DEFF Research Database (Denmark)

Maria J., Sanjuan-Ferrer,; Bravo Gonzalo, Ivan; Bondu, Magalie

2017-01-01

Supercontinuum (SC) light is a well-established technology, which finds applications in several domains ranging from chemistry to material science and imaging systems [1-2]. More specifically, its ultra-wide optical bandwidth and high average power make it an ideal tool for Optical Coherence...... Tomography (OCT). Over the last 5 years, numerous examples have demonstrated its high potential [3-4] in this context. However, SC light sources present pulse-to-pulse intensity variation that can limit the performance of any OCT system [5] by degrading their signal to noise ratio (SNR). To this goal, we...... have studied and compared the noise of several SC light sources and evaluated how their noise properties affect the performance of Ultra-High Resolution OCT (UHR-OCT) at 1300 nm. We have measured several SC light sources with different parameters (pulse length, energy, seed repetition rate, etc.). We...

''High intensity per bunch'' working group

International Nuclear Information System (INIS)

2001-01-01

Third Generation Light Sources are supposed to store high intensity beams not only in many tightly spaced bunches (multibunch operation), but also in few bunch or even single lunch modes of operation, required for example for time structure experiments. Single bunch instabilities, driven by short-range wake fields, however spoil the beam quality, both longitudinally and transversely. Straightforward ways of handling them, by pushing up the chromaticity (ζ = ΔQ/(Δp/p)) for example, enabled to raise the charge per bunch, but to the detriment of beam lifetime. In addition, since the impedance of the vacuum chamber deteriorates with the installation of new insertion devices, the current thresholds tend to dope down continuously. The goal of this Working Group was then to review these limitations in the existing storage rings, where a large number of beam measurements have been performed to characterise them, and to discuss different strategies which are used against them. About 15 different laboratories reported on the present performance of storage rings, experiences gained in high charge per bunch, and on simulation results and theoretical studies. More than 25 presentations addressed the critical issues and stimulated the discussion. Four main topics came out: - Observation and experimental data; - Impedance studies and tracking codes; - Theoretical investigations; - Cures and feedback. (author)

Light at night acutely impairs glucose tolerance in a time-, intensity- and wavelength-dependent manner in rats.

Science.gov (United States)

Opperhuizen, Anne-Loes; Stenvers, Dirk J; Jansen, Remi D; Foppen, Ewout; Fliers, Eric; Kalsbeek, Andries

2017-07-01

Exposure to light at night (LAN) has increased dramatically in recent decades. Animal studies have shown that chronic dim LAN induced obesity and glucose intolerance. Furthermore, several studies in humans have demonstrated that chronic exposure to artificial LAN may have adverse health effects with an increased risk of metabolic disorders, including type 2 diabetes. It is well-known that acute exposure to LAN affects biological clock function, hormone secretion and the activity of the autonomic nervous system, but data on the effects of LAN on glucose homeostasis are lacking. This study aimed to investigate the acute effects of LAN on glucose metabolism. Male Wistar rats were subjected to i.v. glucose or insulin tolerance tests while exposed to 2 h of LAN in the early or late dark phase. In subsequent experiments, different light intensities and wavelengths were used. LAN exposure early in the dark phase at ZT15 caused increased glucose responses during the first 20 min after glucose infusion (p light of 50 and 150 lx induced greater glucose responses than 5 and 20 lx, whereas all intensities other than 5 lx reduced locomotor activity. Green light induced glucose intolerance, but red and blue light did not, suggesting the involvement of a specific retina-brain pathway. Together, these data show that exposure to LAN has acute adverse effects on glucose metabolism in a time-, intensity- and wavelength-dependent manner.

[Effect of light intensity on the growth and digestive enzyme activity of juvenile sea cucumber Apostichopus japonicas under two kinds of culture methods].

Science.gov (United States)

Wei, Zi-Zhong; Zhao, Wen

2014-01-01

The effects of light intensity (0, 1000, 2000 and 3000 1x) on the growth and digestive enzyme activity of juvenile sea cucumber Apostichopus japonicus under two kinds of culture methods (compound Chinese medicine preparation and microbial preparation) were studied. Results showed that the relative mass gain rate (WGR) and the specific growth rate (SGR) of juvenile sea cucumber were significantly affected by light intensity (P sea cucumber under different light intensities were 2000 1x > 1000 1x > 3000 1x > 0 1x. Under the same light intensity, the growth of juvenile sea cucumber under the two kinds of culture methods were significantly different (P sea cucumber. The order of amylase and lipase activity was 2000 1x > 1000 1x > 3000 1x > 0 1x, while that of protease activity was 1000 1x > 2000 1x > 0 1x > 3000 1x. Under the same light intensity, the digestive enzyme activities of the Chinese medicine treatment were generally higher than those of the microbial treatment.

On the anomalous interaction of intense light fluxes with a dense plasma

International Nuclear Information System (INIS)

D'yachenko, V.F.; Imshennik, V.S.

1979-01-01

The process of interaction of a light wave with plasma is considered in the framework of the system of the Maxwell-Vlasov equations without taking accout of particle collisions. The plasma were incident onto the plasma surface is monochromatic and linearly polarized. Plasma is cold and completely ionized. The concentration of charged particles is above critical one and varies in the direction of vector of the wave electric field. The results of several numerical calculations of this problem are presented. They show that if the energy flux density of the wave exceeds some critical one, plasma absorbes light intensively. Studied is the mechanism of nonlinear interaction of oscillations which leads to arising of multiflux motion and explaining this effect

The Light-Emitting Diode as a Light Detector

Science.gov (United States)

Baird, William H.; Hack, W. Nathan; Tran, Kiet; Vira, Zeeshan; Pickett, Matthew

2011-01-01

A light-emitting diode (LED) and operational amplifier can be used as an affordable method to provide a digital output indicating detection of an intense light source such as a laser beam or high-output LED. When coupled with a microcontroller, the combination can be used as a multiple photogate and timer for under $50. A similar circuit is used…

Reduction of Bacterial Pathogens and Potential Surrogates on the Surface of Almonds Using High-Intensity 405-Nanometer Light.

Science.gov (United States)

Lacombe, Alison; Niemira, Brendan A; Sites, Joseph; Boyd, Glenn; Gurtler, Joshua B; Tyrell, Breanna; Fleck, Melissa

2016-11-01

The disinfecting properties of high-intensity monochromatic blue light (MBL) were investigated against Escherichia coli O157:H7, Salmonella , and nonpathogenic bacteria inoculated onto the surface of almonds. MBL was generated from an array of narrow-band 405-nm light-emitting diodes. Almonds were inoculated with higher or lower levels (8 or 5 CFU/g) of pathogenic E. coli O157:H7 and Salmonella , as well as nonpathogenic E. coli K-12 and an avirulent strain of Salmonella Typhimurium, for evaluation as potential surrogates for their respective pathogens. Inoculated almonds were treated with MBL for 0, 1, 2, 4, 6, 8, and 10 min at a working distance of 7 cm. Simultaneous to treatment, cooling air was directed onto the almonds at a rate of 4 ft 3 /min (1.89 ×10 -3 m 3 /s), sourced through a container of dry ice. An infrared camera was used to monitor the temperature readings after each run. For E. coli K-12, reductions of up to 1.85 or 1.63 log CFU/g were seen for higher and lower inoculum levels, respectively; reductions up to 2.44 and 1.44 log CFU/g were seen for E. coli O157:H7 (higher and lower inoculation levels, respectively). Attenuated Salmonella was reduced by up to 0.54 and 0.97 log CFU/g, whereas pathogenic Salmonella was reduced by up to 0.70 and 0.55 log CFU/g (higher and lower inoculation levels, respectively). Inoculation level did not significantly impact minimum effective treatment times, which ranged from 1 to 4 min. Temperatures remained below ambient throughout treatment, indicating that MBL is a nonthermal antimicrobial process. The nonpathogenic strains of E. coli and Salmonella each responded to MBL in a comparable manner to their pathogenic counterparts. These results suggest that these nonpathogenic strains may be useful in experiments with MBL in which a surrogate is required, and that MBL warrants further investigation as a potential antimicrobial treatment for low-moisture foods.

Optical Characteristics of a Multichannel Hybrid Integrated Light Source for Ultra-High-Bandwidth Optical Interconnections

Directory of Open Access Journals (Sweden)

Takanori Shimizu

2015-11-01

Full Text Available The optical characteristics of a multi-channel hybrid integrated light source were described for an optical interconnection with a bandwidth of over 10 Tbit/s. The power uniformity of the relative intensity of a 1000-channel light source was shown, and the minimum standard deviation s of the optical power of the 200 output ports at each 25-channel laser diode (LD array was estimated to be 0.49 dB. This hybrid integrated light source is expected to be easily adaptable to a photonics-electronics convergence system for ultra-high-bandwidth interchip interconnections.

Feasibility of high-intensity training in asthma

DEFF Research Database (Denmark)

Tønnesen, Louise Lindhardt; Sørensen, E D; Hostrup, Morten

2018-01-01

Background: High-intensity interval training is an effective and popular training regime but its feasibility in untrained adults with asthma is insufficiently described. Objective: The randomized controlled trial 'EFFORT Asthma' explored the effects of behavioural interventions including high......-intensity interval training on clinical outcomes in nonobese sedentary adults with asthma. In this article we present a sub analysis of data aiming to evaluate if patients' pre-intervention levels of asthma control, FEV1, airway inflammation and airway hyperresponsiveness (AHR) predicted their training response...... to the high-intensity interval training program, measured as increase in maximal oxygen consumption (VO2max). Design: We used data from the EFFORT Asthma Study. Of the 36 patients randomized to the 8-week exercise intervention consisting of high-intensity training three times per week, 29 patients (45...

Observations of MeV electrons and scattered light from intense, subpicosecond laser-plasma interactions

International Nuclear Information System (INIS)

Darrow, C.; Lane, S.; Klem, D.; Perry, M.D.

1993-01-01

In this paper the authors present work in progress in their experimental investigation of the coupling of intense, subpicosecond laser pulses with plasmas preformed on solid targets. (This situation is to be contrasted with the interaction of intense laser fields with solid-density matter. A subject which has generated considerable interest in the last several years.) The characterization of the energy distribution of energetic electrons which escape a solid target irradiated by an intense laser is discussed. The authors have also performed experiments to study the excitation of parametric instabilities near the quarter-critical layer and second-harmonic generation near the critical layer in the plasma. They discuss some preliminary scattered light spectroscopy measurements

High-power LED light sources for optical measurement systems operated in continuous and overdriven pulsed modes

Science.gov (United States)

Stasicki, Bolesław; Schröder, Andreas; Boden, Fritz; Ludwikowski, Krzysztof

2017-06-01

The rapid progress of light emitting diode (LED) technology has recently resulted in the availability of high power devices with unprecedented light emission intensities comparable to those of visible laser light sources. On this basis two versatile devices have been developed, constructed and tested. The first one is a high-power, single-LED illuminator equipped with exchangeable projection lenses providing a homogenous light spot of defined diameter. The second device is a multi-LED illuminator array consisting of a number of high-power LEDs, each integrated with a separate collimating lens. These devices can emit R, G, CG, B, UV or white light and can be operated in pulsed or continuous wave (CW) mode. Using an external trigger signal they can be easily synchronized with cameras or other devices. The mode of operation and all parameters can be controlled by software. Various experiments have shown that these devices have become a versatile and competitive alternative to laser and xenon lamp based light sources. The principle, design, achieved performances and application examples are given in this paper.

Leaf gas exchange, chlorophyll fluorescence and pigment indexes of Eugenia uniflora L. in response to changes in light intensity and soil flooding.

Science.gov (United States)

Mielke, Marcelo S; Schaffer, Bruce

2010-01-01

The interactive effects of changing light intensity and soil flooding on the photosynthetic performance of Eugenia uniflora L. (Myrtaceae) seedlings in containers were examined. Two hypotheses were tested: (i) the photosynthetic apparatus of shade-adapted leaves can be rapidly acclimated to high light after transfer from shade to full sun, and (ii) photosynthetic acclimation to changing light intensity may be influenced by soil flooding. Seedlings cultivated in a shade house (40% of full sun, approximately 12 mol m(-)(2) day(-)(1)) for 6 months were transferred to full sun (20-40 mol m(-2) day(-1)) or shade (30% of full sun, approximately 8 mol m(-2) day(-1)) and subjected to soil flooding for 23 days or not flooded. Chlorophyll content index (CCI), chlorophyll fluorescence, leaf weight per area (LWA), photosynthetic light-response curves and leaf reflectance indexes were measured during soil flooding and after plants were unflooded. The CCI values increased throughout the experiment in leaves of shaded plants and decreased in leaves of plants transferred to full sun. There were no significant interactions between light intensity and flooding treatments for most of the variables analyzed, with the exception of Fv/Fm 22 days after plants were flooded and 5 days after flooded plants were unflooded. The light environment significantly affected LWA, and light environment and soil flooding significantly affected the light-saturated gross CO(2) assimilation rate expressed on area and dry weight bases (A(max-area) and A(max-wt), respectively), stomatal conductance of water vapor (g(ssat)) and intrinsic water use efficiency (A/g(s)). Five days after flooded plants were unflooded, the normalized difference vegetation index (NDVI) and the scaled photochemical reflectance index (sPRI) were significantly higher in shade than in sun leaves. Thirty days after transferring plants from the shade house to the light treatment, LWA was 30% higher in sun than in shade leaves, and A

Light intensity and thermal responses

NARCIS (Netherlands)

te Kulve, M.; Schellen, L.; Schlangen, L.; Frijns, A.J.H.; van Marken Lichtenbelt, W.D.; Nicol, Fergus; Roaf, Susan; Brotas, Luisa; Humphreys, Michael

2016-01-01

Temperature and light are both major factors in the design of a comfortable indoor environment. Moreover, there might be an interaction between light exposure and human thermal responses. However, results of experiments conducted so far are inconclusive and current understanding of the relation

Optimization of Nanocomposite Solar Cell/Liquid Crystal Matrix to Diminish High Intensity Laser Light Relevant to Aviation Safety Applications

Science.gov (United States)

Hofmann, James A.

V when exposed to both light sources. Additionally, the performance of the DSSCs were correlated to molecular modeling predictions using Spartan software. The stability of TiO2-dye interactions indicated that dye adsorption to the surface of the nanocomposite directly impacted the performance of the DSSCs. Implementation of a LC and DSSC system forces the LCs to transition between its nematic and crystalline phases depending on the wavelength of light that is illuminating the DSSC. This research explores the practicality of using LCs and DSSCs as a preliminary approach to mitigating green laser light illumination on aircraft. Experimental results have shown that DSSCs alone are not capable of forcing a phase transitions in LCs which can entirely mitigate incoming laser light. The intense laser light required to generate substantial voltage (3V) from the DSSCs penetrates the crystalline phase of the LC with minimal attenuation of 5%.

The impact of morning light intensity and environmental temperature on body temperatures and alertness.

Science.gov (United States)

Te Kulve, Marije; Schlangen, Luc J M; Schellen, Lisje; Frijns, Arjan J H; van Marken Lichtenbelt, Wouter D

2017-06-01

Indoor temperature and light exposure are known to affect body temperature, productivity and alertness of building occupants. However, not much is known about the interaction between light and temperature exposure and the relationship between morning light induced alertness and its effect on body temperature. Light intensity and room temperature during morning office hours were investigated under strictly controlled conditions. In a randomized crossover study, two white light conditions (4000K, either bright 1200lx or dim 5lx) under three different room temperatures (26, 29 and 32°C) were investigated. A lower room temperature increased the core body temperature (CBT) and lowered skin temperature and the distal-proximal temperature gradient (DPG). Moreover, a lower room temperature reduced the subjective sleepiness and reaction time on an auditory psychomotor vigilance task (PVT), irrespective of the light condition. Interestingly, the morning bright light exposure did affect thermophysiological parameters, i.e. it decreased plasma cortisol, CBT and proximal skin temperature and increased the DPG, irrespective of the room temperature. During the bright light session, subjective sleepiness decreased irrespective of the room temperature. However, the change in sleepiness due to the light exposure was not related to these physiological changes. Copyright © 2017 Elsevier Inc. All rights reserved.

High-frequency, high-intensity photoionization

Science.gov (United States)

Reiss, H. R.

1996-02-01

Two analytical methods for computing ionization by high-frequency fields are compared. Predicted ionization rates compare well, but energy predictions for the onset of ionization differ radically. The difference is shown to arise from the use of a transformation in one of the methods that alters the zero from which energy is measured. This alteration leads to an apparent energy threshold for ionization that can, especially in the stabilization regime, differ strongly from the laboratory measurement. It is concluded that channel closings in intense-field ionization can occur at high as well as low frequencies. It is also found that the stabilization phenomenon at high frequencies, very prominent for hydrogen, is absent in a short-range potential.

Phenotypic plasticity of Neonotonia wightii and Pueraria phaseoloidesgrown under different light intensities

Directory of Open Access Journals (Sweden)

LEONARDO D.T. SANTOS

2015-03-01

Full Text Available Plants have the ability to undergo morphophysiological changes based on availability of light. The present study evaluated biomass accumulation, leaf morphoanatomy and physiology of Neonotonia wightii andPueraria phaseoloides grown in full sunlight, as well as in 30% and 50% shade. Two assays were performed, one for each species, using a randomized block design with 10 replicates. A higher accumulation of fresh mass in the shoot of the plants was observed for both species under cultivation in 50% shade, while no differences were detected between the full sunlight and 30% shade. N. wightii and P. phaseoloides showed increase in area and reduction in thickness leaf when cultivated in 50% shade. There were no changes in photosynthetic rate, stomatal conductance, water use efficiency and evapotranspiration of P. phaseoloidesplants because growth environment. However, the shade treatments caused alterations in physiological parameters of N. wightii. In both species, structural changes in the mesophyll occurred depending on the availability of light; however, the amount of leaf blade tissue remained unaltered. Despite the influence of light intensity variation on the morphophysiological plasticity ofN. wightiiand P. phaseoloides, no effects on biomass accumulation were observed in response to light.

Lighting for Education.

Science.gov (United States)

Ontario Ministry of Colleges and Universities, Toronto.

Some of the qualities and quantities that must be juggled to produce good lighting for educational facilities are analyzed with photographs, tables, and drawings. The three categories of lamps used for school lighting (incandescent, fluorescent, and high intensity discharge) are described; a lamp selection guide gives the design characteristics of…

Radiation Dose Measurement for High-Intensity Laser Interactions with Solid Targets at SLAC

Energy Technology Data Exchange (ETDEWEB)

Liang, Taiee [SLAC National Accelerator Lab., Menlo Park, CA (United States)

2015-09-25

A systematic study of photon and neutron radiation doses generated in high-intensity laser-solid interactions is underway at SLAC National Accelerator Laboratory. We found that these laser-solid experiments are being performed using a 25 TW (up to 1 J in 40 fs) femtosecond pulsed Ti:sapphire laser at the Linac Coherent Light Source’s (LCLS) Matter in Extreme Conditions (MEC) facility. Additionally, radiation measurements were performed with passive and active detectors deployed at various locations inside and outside the target chamber. Results from radiation dose measurements for laser-solid experiments at SLAC MEC in 2014 with peak intensity between 10¹⁸ to 7.1x10¹⁹ W/cm² are presented.

Light impacts embryonic and early larval development of the European eel, Anguilla anguilla

DEFF Research Database (Denmark)

Politis, Sebastian Nikitas; Butts, Ian; Tomkiewicz, Jonna

2014-01-01

Little is known about the natural ecology of European eel during early life history. Weextend our understandings on the ecology of this species by studying howearly life stages perform under various light regimes.We assessed the effects of intensity, photoperiod (12:12 and 24:0 h light/dark) and ......Little is known about the natural ecology of European eel during early life history. Weextend our understandings on the ecology of this species by studying howearly life stages perform under various light regimes.We assessed the effects of intensity, photoperiod (12:12 and 24:0 h light...... stages. In particular, for the 12:12 h photoperiod, embryonic survival, until 26 h post-fertilization was significantly higher when reared under low (62 ± 13%) than those reared under high intensity light (42 ± 13%). Furthermore, embryos reared in low light had a higher hatch success (16 ± 7%) than those...... in high intensity light (12 ± 7%). Larval yolk-sac area was significantly affected by photoperiod and body area was significantly affected by the interaction between intensity × photoperiod. The highest incidence of deformities (75%) occurred when embryos were reared in high intensity white light under...

Highly stable cesium lead iodide perovskite quantum dot light-emitting diodes

Science.gov (United States)

Zou, Chen; Huang, Chun-Ying; Sanehira, Erin M.; Luther, Joseph M.; Lin, Lih Y.

2017-11-01

Recently, all-inorganic perovskites such as CsPbBr3 and CsPbI3, have emerged as promising materials for light-emitting applications. While encouraging performance has been demonstrated, the stability issue of the red-emitting CsPbI3 is still a major concern due to its small tolerance factor. Here we report a highly stable CsPbI3 quantum dot (QD) light-emitting diode (LED) with red emission fabricated using an improved purification approach. The device achieved decent external quantum efficiency (EQE) of 0.21% at a bias of 6 V and outstanding operational stability, with a L 70 lifetime (EL intensity decreases to 70% of starting value) of 16 h and 1.5 h under a constant driving voltage of 5 V and 6 V (maximum EQE operation) respectively. Furthermore, the device can work under a higher voltage of 7 V (maximum luminance operation) and retain 50% of its initial EL intensity after 500 s. These findings demonstrate the promise of CsPbI3 QDs for stable red LEDs, and suggest the feasibility for electrically pumped perovskite lasers with further device optimizations.

Reversible structural transformation and enhanced performance of PEDOT:PSS-based hybrid solar cells driven by light intensity.

Science.gov (United States)

Thomas, Joseph Palathinkal; Srivastava, Saurabh; Zhao, Liyan; Abd-Ellah, Marwa; McGillivray, Donald; Kang, Jung Soo; Rahman, Md Anisur; Moghimi, Nafiseh; Heinig, Nina F; Leung, Kam Tong

2015-04-15

Hybrid solar cells made of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) ( PSS) and appropriate amounts of a cosolvent and a fluorosurfactant on planar n-type silicon substrates showed a photoconversion efficiency (PCE) of above 13%. These cells also exhibited stable, reproducible, and high external quantum efficiency (EQE) that was not sensitive to light-bias intensity (LBI). In contrast, solar cells made of pristine PSS showed low PCE and high EQE only under certain measurement conditions. The EQE was found to degrade with increasing LBI. Here we report that the LBI-sensitive variation of EQE of the low-PCE cells is related to a reversible structural transformation from a quinoid to a benzoid structure of PEDOT.

Light quantity affects the regulation of cell shape in Fremyella diplosiphon

Directory of Open Access Journals (Sweden)

Bagmi ePattanaik

2012-05-01

Full Text Available In some cyanobacteria, the color or prevalent wavelengths of ambient light can impact the protein or pigment composition of the light-harvesting complexes. In some cases, light color or quality impacts cellular morphology. The significance of changes in pigmentation is associated strongly with optimizing light absorption for photosynthesis, whereas the significance of changes in light quality-dependent cellular morphology is less well understood. In natural aquatic environments, light quality and intensity change simultaneously at varying depths of the water column. Thus, we hypothesize that changes in morphology that also have been attributed to differences in the prevalent wavelengths of available light may largely be associated with changes in light intensity. Fremyella diplosiphon shows highly reproducible light-dependent changes in pigmentation and morphology. Under red light (RL, F. diplosiphon cells are blue-green in color, due to the accumulation of high levels of phycocyanin, a RL- absorbing pigment in the light-harvesting complexes or phycobilisomes (PBSs, and the shape of cells are short and rounded. Conversely, under green light (GL, F. diplosiphon cells are red in color due to accumulation of GL- absorbing phycoerythrin in PBSs, and are longer and brick-shaped. GL is enriched at lower depths in the water column, where overall levels of light also are reduced, i.e., to 10% or less of the intensity found at the water surface. We hypothesize that longer cells under low light intensity, which is generally enriched in green wavelengths, are associated with greater levels of total photosynthetic pigments in the thylakoid membranes. To test this hypothesis, we grew F. diplosiphon under increasing intensities of GL and observed whether the length of cells diminished due to reduced pressure to maintain larger cells and the associated increased photosynthetic membrane capacity under high light intensity, independent of whether it is light of

Development of high intensity beam handling system, 4

International Nuclear Information System (INIS)

Yamanoi, Yutaka; Tanaka, Kazuhiro; Minakawa, Michifumi

1992-01-01

We have constructed the new counter experimental hall at the KEK 12 GeV Proton Synchrotron (KEK-PS) in order to handle high intensity primary proton beams of up to 1x10 3 pps (protons per second), which is one order of magnitude greater than the present beam intensity of the KEK-PS, 1x10 12 pps. New technologies for handling high-intensity beams have, then, been developed and employed in the construction of the new hall. A part of our R/D work on handling high intensity beams will be reported. (author)

High Intensity Source Laboratory (HISL)

International Nuclear Information System (INIS)

1992-01-01

The High Intensity Source Laboratory (HISL) is a laboratory facility operated for the US Department of Energy (DOE) by EG ampersand G, Energy Measurements (EG ampersand G/EM). This document is intended as an overview -- primarily for external users -- of the general purposes and capabilities of HISL; numerous technical details are beyond its scope. Moreover, systems at HISL are added, deleted, and modified to suit current needs, and upgraded with continuing development. Consequently, interested parties are invited to contact the HISL manager for detailed, current, technical, and administrative information. The HISL develops and operates pulsed radiation sources with energies, intensities, and pulse widths appropriate for several applications. Principal among these are development, characterization, and calibration of various high-bandwidth radiation detectors and diagnostic systems. Hardness/vulnerability of electronic or other sensitive components to radiation is also tested. In this connection, source development generally focuses on attending (1) the highest possible intensities with (2) reasonably short pulse widths and (3) comprehensive output characterization

Detection of internal structure by scattered light intensity: Application to kidney cell sorting

Science.gov (United States)

Goolsby, C. L.; Kunze, M. E.

1985-01-01

Scattered light measurements in flow cytometry were sucessfully used to distinguish cells on the basis of differing morphology and internal structure. Differences in scattered light patterns due to changes in internal structure would be expected to occur at large scattering angles. Practically, the results of these calculations suggest that in experimental situations an array of detectors would be useful. Although in general the detection of the scattered light intensity at several intervals within the 10 to 60 region would be sufficient, there are many examples where increased sensitivity could be acheived at other angles. The ability to measure at many different angular intervals would allow the experimenter to empirically select the optimum intervals for the varying conditions of cell size, N/C ratio, granule size and internal structure from sample to sample. The feasibility of making scattered light measurements at many different intervals in flow cytometry was demonstrated. The implementation of simplified versions of these techniques in conjunction with independant measurements of cell size could potentially improve the usefulness of flow cytometry in the study of the internal structure of cells.

Growth and content of Spirulina platensis biomass chlorophyll cultivated at different values of light intensity and temperature using different nitrogen sources

Directory of Open Access Journals (Sweden)

Eliane Dalva Godoy Danesi

2011-03-01

Full Text Available The effects of light intensity and temperature in S. platensis cultivation with potassium nitrate or urea as nitrogen source were investigated, as well as the biomass chlorophyll contents of this cyanobacteria, through the Response Surface Methodology. Experiments were performed at temperatures from 25 to 34.5ºC and light intensities from 15 to 69 µmol photons m-2 s-1, in mineral medium. In cultivations with both sources of nitrogen, KNO3 and urea, statistic evaluation through multiple regression, no interactions of such independent variables were detected in the results of the dependent variables maximum cell concentration, chlorophyll biomass contents, cell and chlorophyll productivities, as well as in the nitrogen-cell conversion factor. In cultivation performed with both sources of nitrogen, it was possible to obtain satisfactory adjustments to relate the dependent variables to the independent variables. The best results were achieved at temperature of 30ºC, at light intensity of 60 µmol photons m-2s-1, for cell growth, with cell productivity of approximately 95 mg L-1 d-1 in cultivations with urea. For the chlorophyll biomass content, the most adequate light intensity was 24 µmol photons m-2 s-1.

75 FR 11920 - General Electric Lighting-Ravenna Lamp Plant, Lighting Division, Including On-Site Leased Workers...

Science.gov (United States)

2010-03-12

... to the production of high intensity discharge lamps. The review shows that on August 24, 2007, a...-Ravenna Lamp Plant, Lighting Division, Including On-Site Leased Workers from Devore Technologies, Ravenna..., 2009, applicable to workers of General Electric Lighting-Ravenna Lamp Plant, Lighting Division...

Adaptation of Rhodopseudomonas acidophila strain 7050 to growth at different light intensities: what are the benefits to changing the type of LH2?

Science.gov (United States)

Gardiner, A T; Niedzwiedzki, D M; Cogdell, R J

2018-04-01

Typical purple bacterial photosynthetic units consist of light harvesting one/reaction centre 'core' complexes surrounded by light harvesting two complexes. Factors such as the number and size of photosynthetic units per cell, as well as the type of light harvesting two complex that is produced, are controlled by environmental factors. In this paper, the change in the type of LH2 present in the Rhodopsuedomonas acidophila strain 7050 is described when cells are grown at a range of different light intensities. This species contains multiple pucBA genes that encode the apoproteins that form light-harvesting complex two, and a more complex mixture of spectroscopic forms of this complex has been found than was previously thought to be the case. Femto-second time resolved absorption has been used to investigate how the energy transfer properties in the membranes of high-light and low-light adapted cells change as the composition of the LH2 complexes varies.

Stopping light in its tracks

Science.gov (United States)

Eggleton, B. J.; Martijn de Sterke, C.; Slusher, R. E.; Krug, Peter A.; Sipe, J. E.

1996-12-01

To control the speed of a light pulse without absorbing its photons, or distorting its shape, is a challenging problem. However, this has been accomplished using fiber gratings, as part of a joint research program of the University of Sydney, the Australian Photonics Research Centre, Lucent Technologies, and the University of Toronto. The gratings are written in the optical fiber's core by directing a UV beam onto it via a periodic phase mask. Through a photochemical process still not well-understood, the periodic intensity pattern burns a permanent index of refraction change in the core.1-2 In our experiments, we use gratings with a period of about 350 nm chosen to reflect light at 1.05 u m and a length of 5.5 cm.3 Because the grating has over 150,000 periods, an index change of only 0.0003 is sufficient to limit the transmission to less than 30 dB on resonance. Essentially no light is transmitted by such a grating at the Bragg resonance; yet a nanometer away, light propagates through as if the grating were absent. As we tune away from resonance, the light's group velocity increases from zero to c/n (where c is the speed of light in a vacuum and n=1.46 is the refractive index of the core of the fiber), leading to a dispersion about 100,000 times larger than that of bare fiber. Gratings can thus slow down a pulse of light, but at the price of tearing it apart.4 At high light intensities a nonlinearly, with the index of refraction increasing with intensity.5 In the center of the pulse, where the intensity is the highest, the index is thus raised the most. Since regions of high index attract light, the nonlinearity acts as a "glue," counteracting the strong dispersive effects of the grating.

Intense pulsed light annealing of copper zinc tin sulfide nanocrystal coatings

Energy Technology Data Exchange (ETDEWEB)

Williams, Bryce A.; Smeaton, Michelle A.; Holgate, Collin S.; Trejo, Nancy D.; Francis, Lorraine F., E-mail: francis@umn.edu; Aydil, Eray S., E-mail: aydil@umn.edu [Department of Chemical Engineering and Materials Science, University of Minnesota, 151 Amundson Hall, 421 Washington Avenue SE, Minneapolis, Minnesota 55455 (United States)

2016-09-15

A promising method for forming the absorber layer in copper zinc tin sulfide [Cu{sub 2}ZnSnS{sub 4} (CZTS)] thin film solar cells is thermal annealing of coatings cast from dispersions of CZTS nanocrystals. Intense pulsed light (IPL) annealing utilizing xenon flash lamps is a potential high-throughput, low-cost, roll-to-roll manufacturing compatible alternative to thermal annealing in conventional furnaces. The authors studied the effects of flash energy density (3.9–11.6 J/cm{sup 2}) and number of flashes (1–400) during IPL annealing on the microstructure of CZTS nanocrystal coatings cast on molybdenum-coated soda lime glass substrates (Mo-coated SLG). The annealed coatings exhibited cracks with two distinct linear crack densities, 0.01 and 0.2 μm{sup −1}, depending on the flash intensity and total number of flashes. Low density cracking (0.01 μm{sup −1}, ∼1 crack per 100 μm) is caused by decomposition of CZTS at the Mo-coating interface. Vapor decomposition products at the interface cause blisters as they escape the coating. Residual decomposition products within the blisters were imaged using confocal Raman spectroscopy. In support of this hypothesis, replacing the Mo-coated SLG substrate with quartz eliminated blistering and low-density cracking. High density cracking is caused by rapid thermal expansion and contraction of the coating constricted on the substrate as it is heated and cooled during IPL annealing. Finite element modeling showed that CZTS coatings on low thermal diffusivity materials (i.e., SLG) underwent significant differential heating with respect to the substrate with rapid rises and falls of the coating temperature as the flash is turned on and off, possibly causing a build-up of tensile stress within the coating prompting cracking. Use of a high thermal diffusivity substrate, such as a molybdenum foil (Mo foil), reduces this differential heating and eliminates the high-density cracking. IPL annealing in presence of sulfur

High Intensity High Charge State ECR Ion Sources

CERN Document Server

Leitner, Daniela

2005-01-01

The next-generation heavy ion beam accelerators such as the proposed Rare Isotope Accelerator (RIA), the Radioactive Ion Beam Factory at RIKEN, the GSI upgrade project, the LHC-upgrade, and IMP in Lanzhou require a great variety of high charge state ion beams with a magnitude higher beam intensity than currently achievable. High performance Electron Cyclotron Resonance (ECR) ion sources can provide the flexibility since they can routinely produce beams from hydrogen to uranium. Over the last three decades, ECR ion sources have continued improving the available ion beam intensities by increasing the magnetic fields and ECR heating frequencies to enhance the confinement and the plasma density. With advances in superconducting magnet technology, a new generation of high field superconducting sources is now emerging, designed to meet the requirements of these next generation accelerator projects. The talk will briefly review the field of high performance ECR ion sources and the latest developments for high intens...

Photon-photon scattering at the high-intensity frontier

Science.gov (United States)

Gies, Holger; Karbstein, Felix; Kohlfürst, Christian; Seegert, Nico

2018-04-01

The tremendous progress in high-intensity laser technology and the establishment of dedicated high-field laboratories in recent years have paved the way towards a first observation of quantum vacuum nonlinearities at the high-intensity frontier. We advocate a particularly prospective scenario, where three synchronized high-intensity laser pulses are brought into collision, giving rise to signal photons, whose frequency and propagation direction differ from the driving laser pulses, thus providing various means to achieve an excellent signal to background separation. Based on the theoretical concept of vacuum emission, we employ an efficient numerical algorithm which allows us to model the collision of focused high-intensity laser pulses in unprecedented detail. We provide accurate predictions for the numbers of signal photons accessible in experiment. Our study is the first to predict the precise angular spread of the signal photons, and paves the way for a first verification of quantum vacuum nonlinearity in a well-controlled laboratory experiment at one of the many high-intensity laser facilities currently coming online.

Fuselage mounted anti-collision lights utilizing high power LEDs

Science.gov (United States)

Lundberg, John; Machi, Nicolo; Mangum, Scott; Singer, Jeffrey

2005-09-01

As LEDs continue to improve in efficacy and total light output, they are increasingly finding their way in to new applications in the aviation industry as well as adjacent markets. One function that is particularly challenging and may reap substantial benefits from this new technology is the fuselage mounted anti-collision light. Anti-collision lights provide conspicuity for the aircraft by periodically emitting bright flashes of light. The color, light distribution and intensity levels for these lights are all closely regulated through Federal Aviation Regulation (FAR) documents. These lighting requirements, along with thermal, environmental and aerodynamic requirements, drive the overall design. In this paper, we will discuss the existing technologies used in anti-collision lights and the advantages and challenges associated with an LED solution. Particular attention will be given to the optical, thermal, electrical and aerodynamic aspects associated with an LED approach. A specific case study will be presented along with some of the challenges that have arisen during the design process. These challenges include the addition of an integrated covert anti-collision lighting.

Application of high-brightness LEDs in aircraft position lights

Science.gov (United States)

Machi, Nicolo; Mangum, Scott; Singer, Jeffrey M.

2004-10-01

Solid state lighting devices have made their way into a number of niche markets and continue to make inroads into other markets as their price / performance ratios improve. One of these markets is aviation lighting. Although this paper will focus on the use of LEDs for aircraft position lights, much of the discussion is applicable to other installations on the interior and exterior of the aircraft. The color, light distribution and intensity levels for a position light are all closely regulated through Code of Federal Regulation (CFR; formerly Federal Aviation Regulation (FAR)) documents. These lighting requirements, along with harsh thermal and environmental requirements, drive the design. In this paper, we will look at these requirements and discuss what is required in order to use LEDs for this type of application. We will explore the optical, thermal and electrical issues associated with the use of LEDs for position lights and examine the specific case study of the Astreon forward position lights. Finally, we will discuss some of the challenges that we see with solid state lighting in current and future aircraft applications.

Light-activation through indirect ceramic restorations: does the overexposure compensate for the attenuation in light intensity during resin cement polymerization?

Directory of Open Access Journals (Sweden)

Albano Luis Novaes Bueno

2011-02-01

Full Text Available OBJECTIVES: This study evaluated the effects of light exposure through simulated indirect ceramic restorations (SICR on hardness (KHN of dual-cured resin cements (RCs, immediately after light-activation and 24 h later. MATERIAL AND METHODS: Three dual-cured RCs were evaluated: Eco-Link (Ivoclar Vivadent, Rely X ARC (3M ESPE, and Panavia F (Kuraray Medical Inc.. The RCs were manipulated in accordance to the manufacturers' instructions and were placed into cylindrical acrylic matrixes (1-mm-thick and 4-mm diameter. The RC light-activation (Optilux 501; Demetron Kerr was performed through a glass slide for 120 s (control group, or through 2-mm or 4-mm thick SICRs (IPS Empress II; Ivoclar Vivadent. The specimens were submitted to KHN analysis immediately and 24 h after light-activation. The data obtained at the 2 evaluation intervals were submitted to 2-way ANOVA repeated measures and post-hoc Tukey's test (pre-set alpha of 5%. RESULTS: Lower KHN was observed when light-activation was performed through SICRs for Eco-Link at all evaluation intervals and for Rely X ARC 24 h later. For Panavia F, no significant difference in KHN was observed between control and experimental groups, regardless of evaluation interval. Most groups exhibited higher KHN after 24 h than immediately after light-activation, with the exception of Rely X ARC light-activated through SICR, as no significant difference in KHN was found between evaluation intervals. CONCLUSIONS: Light overexposure did not compensate for light intensity attenuation due to the presence of SICR when Rely X and Eco-Link were used. Although hardness of such RCs increased over a 24-h interval, the RCs subjected to light overexposure did not reach the hardness values exhibited after direct light exposure.

Generation of shock fronts in the interaction of short pulses of intense laser light in supercritical plasma

International Nuclear Information System (INIS)

Lopez V, V.E.; Ondarza R, R.

2004-01-01

The investigation of the laser interaction with plasma has been carried out mainly in laboratories of Europe, Japan and United States during the last decades. This studies concern the propagation of intense light laser in a non homogeneous plasma, the radiation absorption and the generation of suprathermal electrons, among others. Numerical simulations made by Denavit, for radiation pulses for up of 10 20 W/cm 2 on solid targets, have allowed to observe the generation of ionic crash fronts with high propagation speeds. In this work it is expanded the study of this effect through algorithms of particles simulation. (Author)

Growth, photosynthesis and stress indicators in young rosewood plants (Aniba rosaeodora Ducke) under different light intensities

OpenAIRE

Gonçalves, José Francisco de Carvalho; Barreto, Denize Caranhas de Sousa; Santos Junior, Ulysses Moreira dos; Fernandes, Andreia Varmes; Sampaio, Paulo de Tarso Barbosa; Buckeridge, Marcos Silveira

2005-01-01

Aniba rosaeodora is an Amazonian tree species that belongs to the family Lauraceae. Due to intense exploitation for extraction of essential oils (mainly linalol), A. rosaeodora is now considered an endangered species. On the other hand, there is little information about its ecophysiology which would be useful to support future forest planting programs. Hence, the effect of different light intensities on the growth and photosynthetic characteristics of young plants of A. rosaeodora was studied...

From Intensity Profile to Surface Normal: Photometric Stereo for Unknown Light Sources and Isotropic Reflectances.

Science.gov (United States)

Lu, Feng; Matsushita, Yasuyuki; Sato, Imari; Okabe, Takahiro; Sato, Yoichi

2015-10-01

We propose an uncalibrated photometric stereo method that works with general and unknown isotropic reflectances. Our method uses a pixel intensity profile, which is a sequence of radiance intensities recorded at a pixel under unknown varying directional illumination. We show that for general isotropic materials and uniformly distributed light directions, the geodesic distance between intensity profiles is linearly related to the angular difference of their corresponding surface normals, and that the intensity distribution of the intensity profile reveals reflectance properties. Based on these observations, we develop two methods for surface normal estimation; one for a general setting that uses only the recorded intensity profiles, the other for the case where a BRDF database is available while the exact BRDF of the target scene is still unknown. Quantitative and qualitative evaluations are conducted using both synthetic and real-world scenes, which show the state-of-the-art accuracy of smaller than 10 degree without using reference data and 5 degree with reference data for all 100 materials in MERL database.

The intense pulsed light systems : new treatment possibilities for vascular, pigmented lesions and hair removal

NARCIS (Netherlands)

C.A. Schroeter (Careen)

2004-01-01

textabstractGiven all of the differences in between laser and IPLS devices and the need for additional information in IPLS treatment applications, the aim of this study was to evaluate new treatment possibilities using Intense Pulsed Light Sources and to address the following questions: 1. What

Intense light-elicited upregulation of miR-21 facilitates glycolysis and cardioprotection through Per2-dependent mechanisms.

Directory of Open Access Journals (Sweden)

Colleen Marie Bartman

Full Text Available A wide search for ischemic preconditioning (IPC mechanisms of cardioprotection identified the light elicited circadian rhythm protein Period 2 (Per2 to be cardioprotective. Studies on cardiac metabolism found a key role for light elicited Per2 in mediating metabolic dependence on carbohydrate metabolism. To profile Per2 mediated pathways following IPC of the mouse heart, we performed a genome array and identified 352 abundantly expressed and well-characterized Per2 dependent micro RNAs. One prominent result of our in silico analysis for cardiac Per2 dependent micro RNAs revealed a selective role for miR-21 in the regulation of hypoxia and metabolic pathways. Based on this Per2 dependency, we subsequently found a diurnal expression pattern for miR-21 with higher miR-21 expression levels at Zeitgeber time (ZT 15 compared to ZT3. Gain or loss of function studies for miR-21 using miRNA mimics or miRNA inhibitors and a Seahorse Bioanalyzer uncovered a critical role of miR-21 for cellular glycolysis, glycolytic capacity, and glycolytic reserve. Exposing mice to intense light, a strategy to induce Per2, led to a robust induction of cardiac miR-21 tissue levels and decreased infarct sizes, which was abolished in miR-21-/- mice. Similarly, first translational studies in humans using intense blue light exposure for 5 days in healthy volunteers resulted in increased plasma miR-21 levels which was associated with increased phosphofructokinase activity, the rate-limiting enzyme in glycolysis. Together, we identified miR-21 as cardioprotective downstream target of Per2 and suggest intense light therapy as a potential strategy to enhance miR-21 activity and subsequent carbohydrate metabolism in humans.

Rigorous modelling of light's intensity angular-profile in Abbe refractometers with absorbing homogeneous fluids

International Nuclear Information System (INIS)

García-Valenzuela, A; Contreras-Tello, H; Márquez-Islas, R; Sánchez-Pérez, C

2013-01-01

We derive an optical model for the light intensity distribution around the critical angle in a standard Abbe refractometer when used on absorbing homogenous fluids. The model is developed using rigorous electromagnetic optics. The obtained formula is very simple and can be used suitably in the analysis and design of optical sensors relying on Abbe type refractometry.

High-intensity lower limb endurance training in chronic respiratory disease

OpenAIRE

Tanaka, Takako; Arizono, Shinichi; Hanada, Masatoshi; Senjyu, Hideaki

2015-01-01

High-intensity endurance training is mainly undertaken during pulmonary rehabilitation for patients with chronic respiratory disease. High-intensity endurance training is recommended in many clinical management guidelines. High-intensity endurance training involves training generally at an intensity of at 60-80％ of the patient’s peak work capacity or higher. The effects of high-intensity lower limb endurance training have mostly been investigated in chronic obstructive pulmonary disease （COPD...

Physics of intense light ion beams and production of high energy density in matter. Annual report 1994

International Nuclear Information System (INIS)

Bluhm, H.J.

1995-06-01

This report presents the results obtained in 1994 within the FZK-program on 'Physics of intense ion beams and pulsed plasmas'. It describes the present status of the 6 MW, 2 TW pulsed generator KALIF-HELIA, the production and focussing of high power ion beams and numerical simulations and experiments related to the hydrodynamics of beam matter interaction. (orig.) [de

Application of FEL technique for constructing high-intensity, monochromatic, polarized gamma-sources at storage rings

Energy Technology Data Exchange (ETDEWEB)

Saldin, E.L.; Schneidmiller, E.A.; Ulyanov, Yu.N. [Automatic Systems Corporation, Samara (Russian Federation)] [and others

1995-12-31

A possibility to construct high-intensity tunable monochromatic{gamma}-source at high energy storage rings is discussed. It is proposed to produce {gamma}-quanta by means of Compton backscattering of laser photons on electrons circulating in the storage. The laser light wavelength is chosen in such a way that after the scattering, the electron does not leave the separatrix. So as the probability of the scattering is rather small, energy oscillations are damped prior the next scattering. As a result, the proposed source can operate in {open_quotes}parasitic{close_quote} mode not interfering with the main mode of the storage ring operation. Analysis of parameters of existent storage rings (PETRA, ESRF, Spring-8, etc) shows that the laser light wavelength should be in infrared, {lambda}{approximately} 10 - 400 {mu}m, wavelength band. Installation at storage rings of tunable free-electron lasers with the peak and average output power {approximately} 10 MW and {approximately} 1 kW, respectively, will result in the intensity of the {gamma}-source up to {approximately} 10{sup 14}s{sup -1} with tunable {gamma}-quanta energy from several MeV up to several hundreds MeV. Such a {gamma}-source will reveal unique possibilities for precision investigations in nuclear physics.

LM-OSL signals from some insulators: an analysis of the dependency of the detrapping probability on stimulation light intensity

DEFF Research Database (Denmark)

Bulur, E.; Bøtter-Jensen, L.; Murray, A.S.

2001-01-01

Optically stimulated luminescence (OSL) signals from various insulators including quartz, Al2O3 : C, BeO and NaCl have been studied using the linear modulation OSL (LM-OSL) technique. LM-OSL is based on the linear increase of the stimulation light power from zero to a maximum during the measurement...... is not always correct. The initial decay rates of the blue (similar to 470 nm) light stimulated constant power OSL decay curves were examined to test the relation between the detrapping rates and the stimulation light intensity. In SiO2, Al2O3 : C and BeO a linear relation between the detrapping rates....... The resultant OSL curve initially increases and then decays after reaching a maximum, The analysis of LM-OSL data usually assumes a linear relationship between the detrapping rate and the stimulation light intensity. However, experiments carried out using various insulators have shown that this assumption...

Understanding the molecular mechanisms underlying the effects of light intensity on flavonoid production by RNA-seq analysis in Epimedium pseudowushanense B.L.Guo.

Science.gov (United States)

Pan, Junqian; Chen, Haimei; Guo, Baolin; Liu, Chang

2017-01-01

Epimedium pseudowushanense B.L.Guo, a light-demanding shade herb, is used in traditional medicine to increase libido and strengthen muscles and bones. The recognition of the health benefits of Epimedium has increased its market demand. However, its resource recycling rate is low and environmentally dependent. Furthermore, its natural sources are endangered, further increasing prices. Commercial culture can address resource constraints of it.Understanding the effects of environmental factors on the production of its active components would improve the technology for cultivation and germplasm conservation. Here, we studied the effects of light intensities on the flavonoid production and revealed the molecular mechanism using RNA-seq analysis. Plants were exposed to five levels of light intensity through the periods of germination to flowering, the flavonoid contents were measured using HPLC. Quantification of epimedin A, epimedin B, epimedin C, and icariin showed that the flavonoid contents varied with different light intensity levels. And the largest amount of epimedin C was produced at light intensity level 4 (I4). Next, the leaves under the treatment of three light intensity levels ("L", "M" and "H") with the largest differences in the flavonoid content, were subjected to RNA-seq analysis. Transcriptome reconstruction identified 43,657 unigenes. All unigene sequences were annotated by searching against the Nr, Gene Ontology, and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. In total, 4008, 5260, and 3591 significant differentially expressed genes (DEGs) were identified between the groups L vs. M, M vs. H and L vs. H. Particularly, twenty-one full-length genes involved in flavonoid biosynthesis were identified. The expression levels of the flavonol synthase, chalcone synthase genes were strongly associated with light-induced flavonoid abundance with the highest expression levels found in the H group. Furthermore, 65 transcription factors, including 31

46 CFR 120.410 - Lighting fixtures.

Science.gov (United States)

2010-10-01

...) Each table lamp, desk lamp, floor lamp, or similar equipment must be secured in place so that it cannot... Fixtures,” UL 1571, “Incandescent Lighting Fixtures,” UL 1572, “High Intensity Discharge Lighting Fixtures...

Radiative properties of ceramic metal-halide high intensity discharge lamps containing additives in argon plasma

Science.gov (United States)

Cressault, Yann; Teulet, Philippe; Zissis, Georges

2016-07-01

The lighting represents a consumption of about 19% of the world electricity production. We are thus searching new effective and environment-friendlier light sources. The ceramic metal-halide high intensity lamps (C-MHL) are one of the options for illuminating very high area. The new C-MHL lamps contain additives species that reduce mercury inside and lead to a richer spectrum in specific spectral intervals, a better colour temperature or colour rendering index. This work is particularly focused on the power radiated by these lamps, estimated using the net emission coefficient, and depending on several additives (calcium, sodium, tungsten, dysprosium, and thallium or strontium iodides). The results show the strong influence of the additives on the power radiated despite of their small quantity in the mixtures and the increase of visible radiation portion in presence of dysprosium.

ELECTRON CLOUD EFFECTS IN HIGH INTENSITY PROTON ACCELERATORS

International Nuclear Information System (INIS)

Wei, J.; Macek, R.J.

2002-01-01

One of the primary concerns in the design and operation of high-intensity proton synchrotrons and accumulators is the electron cloud and associated beam loss and instabilities. Electron-cloud effects are observed at high-intensity proton machines like the Los Alamos National Laboratory's PSR and CERN's SPS, and investigated experimentally and theoretically. In the design of next-generation high-intensity proton accelerators like the Spallation Neutron Source ring, emphasis is made in minimizing electron production and in enhancing Landau damping. This paper reviews the present understanding of the electron-cloud effects and presents mitigation measures

Modeling the interaction of light intensity, nutrient concentration and uranium toxicity in Lemna minor

Energy Technology Data Exchange (ETDEWEB)

Zimmer, E.; Horemans, N.; Vandenhove, H. [Belgian Nuclear Research Centre SCK-CEN (Belgium); Cedergreen, N. [University of Copenhagen (Denmark); Jager, T. [Vrije Universiteit Amsterdam (Netherlands)

2014-07-01

Radioecology aims at assessing the effect of radionuclides and radiation on the environment. Since we cannot test every possible environmental situation in the laboratory, we need modeling approaches to extrapolate the results of toxicity assays to environmentally relevant scenarios. Therefore, it is of crucial importance to understand the effect of relevant environmental factors, such as nutrients, temperature and light on the toxicity of the test. Radionuclides are often found to induce the production of reactive oxygen species (ROS). In plants, an overload of ROS can lead to disturbances of the photosynthetic system. Since the light intensity determines the efficiency of the photo-systems in plants, it can be expected to interact with the effect of radionuclides. The nutrient concentration of the test medium determines the physiological state of the plant, affecting in turn the plant's capability of dealing with stress and hence influences the toxicity of the contaminant. To study the interaction of stressors with environmental conditions, mechanistic effect modeling is promoted widely in ecotoxicology. In principle, the modelling aims at a mechanistic understanding of the different processes causing the stress individually, and integrating them in one framework to study their joint effect and possible interaction. We here present a mechanistic effect model for Lemna minor (common duckweed), which is based on Dynamic Energy Budget (DEB) theory. Models based on DEB have been used widely to study the effects of compounds on animals. Due to its general applicability to all types of organisms, it holds potential to be used for comparison of species and compounds in a broad context. Energy uptake from the environment is modeled explicitly, and metabolic rates are set to depend on temperature in DEB models. Therefore, they can be used to extrapolate effects to a wide range of environmentally relevant scenarios. Until now, the DEB research in ecotoxicology has

Selective detection of Escherichia coli by imaging of the light intensity transmitted through an optical disk

Science.gov (United States)

Shiramizu, Hideyuki; Kuroda, Chiaki; Ohki, Yoshimichi; Shima, Takayuki; Wang, Xiaomin; Fujimaki, Makoto

2018-03-01

We have developed an optical disk system for imaging transmitted light from Escherichia coli dispersed on an optical disk. When E. coli was stained using Bismarck brown, the transmittance was found to decrease in images obtained at λ = 405 nm. The results indicate that transmittance imaging is suitable for finding the difference in light intensity between stained and unstained E. coli, whereas the reflectance images were scarcely changed by staining. Therefore, E. coli can be selectively discriminated from abiotic contaminants using transmittance imaging.

Interaction of ultra-high intensity laser pulse with a mass limited targets

International Nuclear Information System (INIS)

Andreev, A.A.; Platonov, K.Yu.; Limpouch, J.; Psikal, J.; Kawata, S.

2006-01-01

and ions. When MLT is irradiated by ultra-high power laser pulse, the resulting plasma is strongly accelerated forward by the laser-induced ponderomotive force and its front side significantly compressed into a high density shock layer. The electrons in the shock layer are heated, and the plasma bunch then expands as a rocket. Thus, the forward acceleration of the high density region continues even after the laser pulse. The ion kinetic energy in this region can exceed tens of MeV at approximately solid density. For laser intensities above Coulomb threshold the efficiency of laser energy conversion into ion energy increases and the regime of direct plasma acceleration by light pressure may be reached. Since the plasma bunch is moving forward during the reflection, red-shift of the reflected light is observed. Twice higher maximum fast ion energy was found for droplet target compared to the standard thin foil target. In simulations of MLT including two different ion sorts, the observed maximum in the light ion distribution is caused by their additional acceleration in the electrostatic field of heavy ions. Parameters of this pike are determined by laser intensity and by the ion concentration ratio.

Production and Studies of Photocathodes for High Intensity Electron Beams

CERN Document Server

Chevallay, E; Legros, P; Suberlucq, Guy; Trautner, H

2000-01-01

For short, high-intensity electron bunches, alkali-tellurides have proved to be a reliable photo-cathode material. Measurements of lifetimes in an rf gun of the CLIC Test Facility II at field strengths greater than 100 MV/m are presented. Before and after using them in this gun, the spectral response of the CS-Te and Rb-Te cathodes were determined with the help of an optical parametric oscillator. The behaviour of both materials can be described by Spicer's 3-step model. Whereas during the use the threshold for photo-emission in Cs-Te was shifted to higher proton energies, that of Rb-Te did not change. Our latest investigations on the stoichiometric ratio of the components are shown. The preparation of the photo-cathodes was monitored with 320 nm wavelength light , with the aim of improving the measurement sensitivity. The latest results on the protection of Cs-Te cathode surfaces with CsBr against pollution are summarized. New investigations on high mean current production are presented.,

Photosynthetic recovery and acclimation to excess light intensity in the rehydrated lichen soil crusts.

Directory of Open Access Journals (Sweden)

Li Wu

Full Text Available As an important successional stage and main type of biological soil crusts (BSCs in Shapotou region of China (southeastern edge of Tengger Desert, lichen soil crusts (LSCs often suffer from many stresses, such as desiccation and excess light intensity. In this study, the chlorophyll fluorescence and CO2 exchange in the rehydrated LSCs were detected under a series of photosynthetically active radiation (PAR gradients to study the photosynthetic acclimation of LSCs. The results showed that although desiccation leaded to the loss of photosynthetic activity in LSCs, the fluorescence parameters including Fo, Fv and Fv/Fm of LSCs could be well recovered after rehydration. After the recovery of photosynthetic activity, the effective photosynthetic efficiency ΦPSII detected by Imaging PAM had declined to nearly 0 within both the lichen thallus upper and lower layers when the PAR increased to 200 μE m-2 s-1, however the net photosynthesis detected by the CO2 gas analyzer in the LSCs still appeared when the PAR increased to 1000 μE m-2 s-1. Our results indicate that LSCs acclimating to high PAR, on the one hand is ascribed to the special structure in crust lichens, making the incident light into the lichen thallus be weakened; on the other hand the massive accumulation of photosynthetic pigments in LSCs also provides a protective barrier for the photosynthetic organisms against radiation damage. Furthermore, the excessive light energy absorbed by crust lichens is also possibly dissipated by the increasing non-photochemical quenching, therefore to some extent providing some protection for LSCs.

Recycled Thermal Energy from High Power Light Emitting Diode Light Source.

Science.gov (United States)

Ji, Jae-Hoon; Jo, GaeHun; Ha, Jae-Geun; Koo, Sang-Mo; Kamiko, Masao; Hong, JunHee; Koh, Jung-Hyuk

2018-09-01

In this research, the recycled electrical energy from wasted thermal energy in high power Light Emitting Diode (LED) system will be investigated. The luminous efficiency of lights has been improved in recent years by employing the high power LED system, therefore energy efficiency was improved compared with that of typical lighting sources. To increase energy efficiency of high power LED system further, wasted thermal energy should be re-considered. Therefore, wasted thermal energy was collected and re-used them as electrical energy. The increased electrical efficiency of high power LED devices was accomplished by considering the recycled heat energy, which is wasted thermal energy from the LED. In this work, increased electrical efficiency will be considered and investigated by employing the high power LED system, which has high thermal loss during the operating time. For this research, well designed thermoelement with heat radiation system was employed to enhance the collecting thermal energy from the LED system, and then convert it as recycled electrical energy.

ELECTRON CLOUD EFFECTS IN HIGH INTENSITY PROTON ACCELERATORS.

Energy Technology Data Exchange (ETDEWEB)

WEI,J.; MACEK,R.J.

2002-04-14

One of the primary concerns in the design and operation of high-intensity proton synchrotrons and accumulators is the electron cloud and associated beam loss and instabilities. Electron-cloud effects are observed at high-intensity proton machines like the Los Alamos National Laboratory's PSR and CERN's SPS, and investigated experimentally and theoretically. In the design of next-generation high-intensity proton accelerators like the Spallation Neutron Source ring, emphasis is made in minimizing electron production and in enhancing Landau damping. This paper reviews the present understanding of the electron-cloud effects and presents mitigation measures.

Influence of temperature and light intensity on Ru(II) complex based organic-inorganic device

International Nuclear Information System (INIS)

Asubay, Sezai; Durap, Feyyaz; Aydemir, Murat; Baysal, Akin; Ocak, Yusuf Selim; Tombak, Ahmet

2016-01-01

An organic-inorganic junction was fabricated by forming [Ru(Cy_2PNHCH_2-C_4H_3O)(η"6-p-cymene)Cl_2] complex thin film using spin coating technique on n-Si and evaporating Au metal on the film. It was seen that the structure had perfect rectification property. Current-voltage (I-V) measurements were carried out in dark and under various illumination conditions (between 50-100 mW/cm"2) and with the temperature range from 303 to 380 K. The structure showed unusually forward and reverse bias temperature and light sensing behaviors. It was seen that the current both in forward and reverse bias increased with the increase in light intensity and temperature.

Development of high intensity proton accelerator

International Nuclear Information System (INIS)

Mizumoto, M.; Kusano, J.; Hasegawa, K.; Ouchi, N.; Oguri, H.; Kinsho, M.; Touchi, Y.; Honda, Y.; Mukugi, K.; Ino, H.; Noda, F.; Akaoka, N.; Kaneko, H.; Chishiro, E.; Fechner, B.

1997-01-01

The high-intensity proton linear accelerator with an energy of 1.5 GeV and an average current of 5.33mA has been proposed for the Neutron Science Project (NSP) at JAERI. the NSP is aiming at exploring nuclear technologies for nuclear waste transmutation based on a proton induced spallation neutrons. The proposed accelerators facilities will be also used in the various basic research fields such as condensed matter physics in combination with a high intensity proton storage ring. The R and D work has been carried out for the components of the front-end of the proton accelerator. For the high energy portion above 100 MeV, superconducting (SC) accelerator linac has been designed and developed as a major option. (Author) 7 refs

Photo-protection in the centric diatom Coscinodiscus granii is not controlled by chloroplast high-light avoidance movement.

Directory of Open Access Journals (Sweden)

Johannes Wilhelm Goessling

2016-01-01

Full Text Available Diatoms are important phototrophs in the worlds’ oceans contributing approximately 40% of the global primary photosynthetic production. This is partially explained by their capacity to exploit environments with variable light conditions, but there is limited knowledge on how diatoms cope with changes in the spectral composition and intensity of light. In this study, the influence of light quality and high irradiance on photosynthesis in the centric diatom Coscinodiscus granii was investigated with microscopic imaging and variable chlorophyll fluorescence techniques. Determination of the wavelength-dependent functional absorption cross-section of photosystem (PS II revealed that absorption of blue light (BL and red light (RL was 2.3-fold and 0.8-fold that of white light (WL, respectively. Hence, BL was more efficiently converted into photo-chemical energy. Excessive energy from BL was dissipated via non-photochemical quenching (NPQ mechanisms, while RL apparently induced only negligible NPQ even at high irradiance. A dose dependent increase of cells exhibiting an altered chloroplast distribution was observed after exposure to high levels of BL and WL, but not RL. However, no effective quantum yield of PSII was measured in the majority of cells with an altered chloroplast distribution, and positive Sytox green® death staining confirmed that most of these cells were dead. We conclude that although Coscinodiscus granii can sustain high irradiance it does not perform chloroplast high-light avoidance movements for photo-protection.

SALIVARY CORTISOL RESPONSES AND PERCEIVED EXERTION DURING HIGH INTENSITY AND LOW INTENSITY BOUTS OF RESISTANCE EXERCISE

Directory of Open Access Journals (Sweden)

Alison D. Egan

2004-03-01

Full Text Available The purpose of this study was to measure the salivary cortisol response to different intensities of resistance exercise. In addition, we wanted to determine the reliability of the session rating of perceived exertion (RPE scale to monitor resistance exercise intensity. Subjects (8 men, 9 women completed 2 trials of acute resistance training bouts in a counterbalanced design. The high intensity resistance exercise protocol consisted of six, ten-repetition sets using 75% of one repetition maximum (RM on a Smith machine squat and bench press exercise (12 sets total. The low intensity resistance exercise protocol consisted of three, ten-repetition sets at 30% of 1RM of the same exercises as the high intensity protocol. Both exercise bouts were performed with 2 minutes of rest between each exercise and sessions were repeated to test reliability of the measures. The order of the exercise bouts was randomized with least 72 hours between each session. Saliva samples were obtained immediately before, immediately after and 30 mins following each resistance exercise bout. RPE measures were obtained using Borg's CR-10 scale following each set. Also, the session RPE for the entire exercise session was obtained 30 minutes following completion of the session. There was a significant 97% increase in the level of salivary cortisol immediately following the high intensity exercise session (P<0.05. There was also a significant difference in salivary cortisol of 145% between the low intensity and high intensity exercise session immediately post-exercise (P<0.05. The low intensity exercise did not result in any significant changes in cortisol levels. There was also a significant difference between the session RPE values for the different intensity levels (high intensity 7.1 vs. low intensity 1.9 (P<0.05. The intraclass correlation coefficient for the session RPE measure was 0.95. It was concluded that the session RPE method is a valid and reliable method of

Auroral lights created by high-power radiowaves in the ionospheric E region

International Nuclear Information System (INIS)

Kagan, L M

2008-01-01

Artificial auroral lights are optical emissions induced by high-power radiowaves in a manner similar to the creation of natural auroral lights due to precipitation of superthermal electrons. Here the Earth's atmosphere itself plays the role of a plasma laboratory. A high-power radio-transmitter creates superthermal electrons in situ due to radiowave interactions with the ionospheric plasma. Low-altitude (85-125 km) artificial aurora is a relatively rare phenomenon observed for the first time about 10 years ago. Analysis of available observations shows that its intensity and structure, as well as the very possibility of its generation at these altitudes, depend largely on the presence and features of so-called sporadic ionization, best known for its effect on navigation and communication. Thus, all other parameters unchanged, a 20 times increase in the height-extent of sporadic ionization clouds could under certain circumstances result in a 27-fold increase in the intensity of the low-altitude artificial aurora. Understanding the morphology and typical features of sporadic ionization clouds for a given location would allow proper planning of experimental campaigns and noticeably extend our knowledge of the atmosphere and its use for human needs. Equally important is that low-altitude artificial auroras give information about the horizontal structure and dynamics of E-region sporadic ionization, the airglow-source region, the energy of superthermal electrons and perhaps the local atmospheric temperature and water vapor content at 80-90 km

Associations of low-intensity light physical activity with physical performance in community-dwelling elderly Japanese: A cross-sectional study.

Directory of Open Access Journals (Sweden)

Kazuhiro P Izawa

Full Text Available Physical activity and physical performance relate to quality of life, mortality, and morbidity in elderly people. However, little is known about differences in physical performance related to low-intensity light physical activity (LLPA, high-intensity light physical activity (HLPA, and moderate-intensity physical activity (MPA and how they are separated by sex in elderly populations.This study aimed to determine differences in LLPA, HLPA, MPA, and physical performance, and associations between these measures in community-dwelling elderly men and women.Physical activity and physical performance such as timed-up-and-go test, one-leg standing time, and maximum gait speed were measured in 181 community-dwelling elderly men (mean age, 75.1 ± 5.3 years and 109 women (mean age, 73.4 ± 4.8 years in 2013. Physical activity was classified as LLPA (1.6~1.9 METs of physical activity, HLPA (2.0~2.9 METs of physical activity, and MPA (over 3 METs of physical activity. The association between the values of these three intensities of physical activity in the participants was assessed by Pearson's correlation coefficients. Multiple linear regression analyses were used to assess the association of physical performance values with the three groups defined by accelerometer-measured physical activity intensity adjusted for sociographic, behavioral, and multiple diseases in the participants.MPA was beneficially associated with all physical performance indicators in the men (all P<0.05 and women (all P<0.05. Only HLPA showed significant associations with the timed-up-and-go test (P = 0.001 and maximum gait speed (P = 0.006 in women.These results may support the notion that not only HLPA in women but MPA in both sexes appears to improve physical performance in elderly populations.The present study findings provide novel epidemiological evidence for the potential benefits of HLPA in women and also reinforce the potential benefits of MPA in both sexes, which is the

High-power light-emitting diode based facility for plant cultivation

Energy Technology Data Exchange (ETDEWEB)

Tamulaitis, G [Institute of Materials Science and Applied Research, Vilnius University, Sauletekio al. 9-III, LT-10222 Vilnius (Lithuania); Duchovskis, P [Lithuanian Institute of Horticulture, Babtai, LT-54333 Kaunas District (Lithuania); Bliznikas, Z [Institute of Materials Science and Applied Research, Vilnius University, Sauletekio al. 9-III, LT-10222 Vilnius (Lithuania); Breive, K [Institute of Materials Science and Applied Research, Vilnius University, Sauletekio al. 9-III, LT-10222 Vilnius (Lithuania); Ulinskaite, R [Lithuanian Institute of Horticulture, Babtai, LT-54333 Kaunas District (Lithuania); Brazaityte, A [Lithuanian Institute of Horticulture, Babtai, LT-54333 Kaunas District (Lithuania); Novickovas, A [Institute of Materials Science and Applied Research, Vilnius University, Sauletekio al. 9-III, LT-10222 Vilnius (Lithuania); Zukauskas, A [Institute of Materials Science and Applied Research, Vilnius University, Sauletekio al. 9-III, LT-10222 Vilnius (Lithuania)

2005-09-07

Based on perspectives of the development of semiconductor materials systems for high-power light-emitting diodes (LEDs), an illumination facility for greenhouse plant cultivation was designed with the dominating 640 nm photosynthetically active component delivered by AlGaInP LEDs and supplementary components from AlGaN (photothropic action, 455 nm) and AlGaAs (photosynthetic 660 nm and photomorphogenetic 735 nm) LEDs. Photosynthesis intensity, photosynthetic productivity and growth morphology as well as chlorophyll and phytohormone concentrations were investigated in radish and lettuce grown in phytotron chambers under the LED-based illuminators and under high-pressure sodium (HPS) lamps with an equivalent photon flux density. Advantages of the high-power LED-based illuminators over conventional HPS lamps, applicability of AlGaInP LEDs for photosynthesis and control of plant growth by circadian manipulation of a relatively weak far-red component were demonstrated.

High-power light-emitting diode based facility for plant cultivation

International Nuclear Information System (INIS)

Tamulaitis, G; Duchovskis, P; Bliznikas, Z; Breive, K; Ulinskaite, R; Brazaityte, A; Novickovas, A; Zukauskas, A

2005-01-01

Based on perspectives of the development of semiconductor materials systems for high-power light-emitting diodes (LEDs), an illumination facility for greenhouse plant cultivation was designed with the dominating 640 nm photosynthetically active component delivered by AlGaInP LEDs and supplementary components from AlGaN (photothropic action, 455 nm) and AlGaAs (photosynthetic 660 nm and photomorphogenetic 735 nm) LEDs. Photosynthesis intensity, photosynthetic productivity and growth morphology as well as chlorophyll and phytohormone concentrations were investigated in radish and lettuce grown in phytotron chambers under the LED-based illuminators and under high-pressure sodium (HPS) lamps with an equivalent photon flux density. Advantages of the high-power LED-based illuminators over conventional HPS lamps, applicability of AlGaInP LEDs for photosynthesis and control of plant growth by circadian manipulation of a relatively weak far-red component were demonstrated

Benefits of High-Intensity Intensive Care Unit Physician Staffing under the Affordable Care Act

Directory of Open Access Journals (Sweden)

Sachin Logani

2011-01-01

Full Text Available The Affordable Care Act signed into law by President Obama, with its value-based purchasing program, is designed to link payment to quality processes and outcomes. Treatment of critically ill patients represents nearly 1% of the gross domestic product and 25% of a typical hospital budget. Data suggest that high-intensity staffing patterns in the intensive care unit (ICU are associated with cost savings and improved outcomes. We evaluate the literature investigating the cost-effectiveness and clinical outcomes of high-intensity ICU physician staffing as recommended by The Leapfrog Group (a consortium of companies that purchase health care for their employees and identify ways to overcome barriers to nationwide implementation of these standards. Hospitals that have implemented the Leapfrog initiative have demonstrated reductions in mortality and length of stay and increased cost savings. High-intensity staffing models appear to be an immediate cost-effective way for hospitals to meet the challenges of health care reform.

Lighting Options for Homes.

Energy Technology Data Exchange (ETDEWEB)

Baker, W.S.

1991-04-01

This report covers many aspects of various lighting options for homes. Types of light sources described include natural light, artificial light, incandescent lamps, fluorescent lamps, and high intensity discharge lamps. A light source selection guide gives the physical characteristics of these, design considerations, and common applications. Color, strategies for efficient lighting, and types of lighting are discussed. There is one section giving tips for various situations in specific rooms. Rooms and types of fixtures are shown on a matrix with watts saved by using the recommended type lighting for that room and room location. A major emphasis of this report is saving energy by utilizing the most suitable, recommended lighting option. (BN)

Effect of Light Curing Unit Characteristics on Light Intensity Output ...

African Journals Online (AJOL)

Background: Modern dental composite restorations are wholly dependent on the use of Visible Light Curing devices. The characteristics of these devices may influence the quality of composite resin restorations. Objective: To determine the characteristics of light curing units (LCUs) in dental clinics in Nairobi and their effect ...

Light-induced vegetative anthocyanin pigmentation in Petunia

OpenAIRE

Albert, Nick W.; Lewis, David H.; Zhang, Huaibi; Irving, Louis J.; Jameson, Paula E.; Davies, Kevin M.

2009-01-01

The Lc petunia system, which displays enhanced, light-induced vegetative pigmentation, was used to investigate how high light affects anthocyanin biosynthesis, and to assess the effects of anthocyanin pigmentation upon photosynthesis. Lc petunia plants displayed intense purple anthocyanin pigmentation throughout the leaves and stems when grown under high-light conditions, yet remain acyanic when grown under shade conditions. The coloured phenotypes matched with an accumulation of anthocyanins...

Understanding the molecular mechanisms underlying the effects of light intensity on flavonoid production by RNA-seq analysis in Epimedium pseudowushanense B.L.Guo.

Directory of Open Access Journals (Sweden)

Junqian Pan

Full Text Available Epimedium pseudowushanense B.L.Guo, a light-demanding shade herb, is used in traditional medicine to increase libido and strengthen muscles and bones. The recognition of the health benefits of Epimedium has increased its market demand. However, its resource recycling rate is low and environmentally dependent. Furthermore, its natural sources are endangered, further increasing prices. Commercial culture can address resource constraints of it.Understanding the effects of environmental factors on the production of its active components would improve the technology for cultivation and germplasm conservation. Here, we studied the effects of light intensities on the flavonoid production and revealed the molecular mechanism using RNA-seq analysis. Plants were exposed to five levels of light intensity through the periods of germination to flowering, the flavonoid contents were measured using HPLC. Quantification of epimedin A, epimedin B, epimedin C, and icariin showed that the flavonoid contents varied with different light intensity levels. And the largest amount of epimedin C was produced at light intensity level 4 (I4. Next, the leaves under the treatment of three light intensity levels ("L", "M" and "H" with the largest differences in the flavonoid content, were subjected to RNA-seq analysis. Transcriptome reconstruction identified 43,657 unigenes. All unigene sequences were annotated by searching against the Nr, Gene Ontology, and Kyoto Encyclopedia of Genes and Genomes (KEGG databases. In total, 4008, 5260, and 3591 significant differentially expressed genes (DEGs were identified between the groups L vs. M, M vs. H and L vs. H. Particularly, twenty-one full-length genes involved in flavonoid biosynthesis were identified. The expression levels of the flavonol synthase, chalcone synthase genes were strongly associated with light-induced flavonoid abundance with the highest expression levels found in the H group. Furthermore, 65 transcription factors

Radiophotoluminescence light scope for high-dose dosimetry

International Nuclear Information System (INIS)

Sato, Fuminobu; Zushi, Naoki; Sakiyama, Tomoki; Kato, Yushi; Murata, Isao; Shimizu, Kikuo; Yamamoto, Takayoshi; Iida, Toshiyuki

2015-01-01

A radiophotoluminescence (RPL) light scope is a remote-sensing technique for measuring in situ the radiation dose in an RPL detector placed at a distance. The RPL light scope is mainly composed of an ultraviolet (UV) pulse laser, telescopic lenses, a photomultiplier tube, and camera modules. In a performance test, some RPL detectors were placed at distances up to 30 m and were illuminated with a pulsed UV laser beam. The photoluminescence responses of the RPL detectors were analyzed using this scope. Their radiation doses were determined from the amplitude of the given component of the photoluminescence responses. The RPL readout could be repeated without fading, and its amplitude exhibited good linearity at a dose ranging from 0.1 to 60 Gy. Furthermore, a two-dimensional distribution of radiation dose was obtained by laser scanning on an RPL detector. It was confirmed that the RPL light scope was a useful remote-sensing tool for high-dose dosimetry. - Highlights: • A radiophotoluminescence (RPL) light scope was developed for high-dose dosimetry. • The RPL light scope has high sensitivity and accuracy in high-dose dosimetry. • Two-dimensional radiation dose distribution was obtained by the RPL light scope.

Impact of light polarization on photoluminescence intensity and quantum efficiency in AlGaN and AlInGaN layers

Science.gov (United States)

Netzel, C.; Knauer, A.; Weyers, M.

2012-12-01

We analyzed emission intensity, quantum efficiency, and emitted light polarization of c-plane AlGaN and AlInGaN layers (λ = 320-350 nm) by temperature dependent photoluminescence. Low indium content in AlInGaN structures causes a significant intensity increase by change of the polarization of the emitted light. Polarization changes from E ⊥ c to E ‖ c with increasing aluminum content. It switches back to E ⊥ c with the incorporation of indium. The polarization degree decreases with temperature. This temperature dependence can corrupt internal quantum efficiency determination by temperature dependent photoluminescence.

High-intensity interval training evokes larger serum BDNF levels compared with intense continuous exercise.

Science.gov (United States)

Saucedo Marquez, Cinthia Maria; Vanaudenaerde, Bart; Troosters, Thierry; Wenderoth, Nicole

2015-12-15

Exercise can have a positive effect on the brain by activating brain-derived neurotrophic factor (BDNF)-related processes. In healthy humans there appears to be a linear relationship between exercise intensity and the positive short-term effect of acute exercise on BDNF levels (i.e., the highest BDNF levels are reported after high-intensity exercise protocols). Here we performed two experiments to test the effectiveness of two high-intensity exercise protocols, both known to improve cardiovascular health, to determine whether they have a similar efficacy in affecting BDNF levels. Participants performed a continuous exercise (CON) protocol at 70% of maximal work rate and a high-intensity interval-training (HIT) protocol at 90% of maximal work rate for periods of 1 min alternating with 1 min of rest (both protocols lasted 20 min). We observed similar BDNF kinetics in both protocols, with maximal BDNF concentrations being reached toward the end of training (experiment 1). We then showed that both exercise protocols significantly increase BDNF levels compared with a rest condition (CON P = 0.04; HIT P exercise are slightly more effective than continuous high-intensity exercise for elevating serum BDNF. Additionally, 73% of the participants preferred the HIT protocol (P = 0.02). Therefore, we suggest that the HIT protocol might represent an effective and preferred intervention for elevating BDNF levels and potentially promoting brain health. Copyright © 2015 the American Physiological Society.

High visibility temporal ghost imaging with classical light

Science.gov (United States)

Liu, Jianbin; Wang, Jingjing; Chen, Hui; Zheng, Huaibin; Liu, Yanyan; Zhou, Yu; Li, Fu-li; Xu, Zhuo

2018-03-01

High visibility temporal ghost imaging with classical light is possible when superbunching pseudothermal light is employed. In the numerical simulation, the visibility of temporal ghost imaging with pseudothermal light, equaling (4 . 7 ± 0 . 2)%, can be increased to (75 ± 8)% in the same scheme with superbunching pseudothermal light. The reasons for that the retrieved images are different for superbunching pseudothermal light with different values of degree of second-order coherence are discussed in detail. It is concluded that high visibility and high quality temporal ghost image can be obtained by collecting sufficient number of data points. The results are helpful to understand the difference between ghost imaging with classical light and entangled photon pairs. The superbunching pseudothermal light can be employed to improve the image quality in ghost imaging applications.

Apparatus for controlled mixing in a high intensity mixer

International Nuclear Information System (INIS)

Crocker, Z.; Gupta, V.P.

1982-01-01

An apparatus and a process is disclosed for controlled mixing of a mixable material in a high intensity mixer. The system enables instantaneous, precise and continual monitoring of a batch in a high intensity mixer which heretofore could not be achieved. The process comprises the steps of feeding a batch of material into a high intensity mixer, agitating the batch in the mixer, monitoring batch temperature separately from mixer temperature and discharging the batch from the mixer when the batch temperature reaches a final predetermined level. The apparatus includes means for monitoring batch temperature in a high intensity mixer separately from mixer temperature, and means responsive to the batch temperature to discharge the batch when the batch temperature reaches a final predetermined level

Production of high intensity electron bunches for the SLAC Linear Collider

International Nuclear Information System (INIS)

James, M.B.

1987-08-01

This thesis describes the design and performance of a high intensity electron injecfor for the SLAC Linear Collider. Motivation for the collider and the specifications for the injector are discussed. An analytic theory of the bunching and capture of electrons by rf fields is discussed in the limit of low space charge and small signal. The design and performance of SLAC's main injector are described to illustrate a successful application of this theory. The bunching and capture of electrons by rf fields are then discussed in the limit of high space charge and large signal, and a description of the design of the collider injector follows. In the limit of high space charge forces and large rf signals, the beam dynamics are considerably more complex and numerical simulations are required to predict particle motion. A computer code which models the longitudinal dynamics of electrons in the presence of space charge and rf fields is described. The results of the simulations, the resulting collider injector design and the various components which make up the collider injector are described. These include the gun, subharmonic bunchers, traveling-wave buncher and velocity-of-light accelerator section. Finally, the performance of the injector is described including the beam intensity, bunch length, transverse emittance and energy spectrum. While the final operating conditions differ somewaht from the design, the performance of the collider injector is in good agreement with the numerical simulations and meets all of the collider specifications. 28 refs

Modulating emission intensity of GaN-based green light emitting diodes on c-plane sapphire

International Nuclear Information System (INIS)

Du, Chunhua; Ma, Ziguang; Zhou, Junming; Lu, Taiping; Jiang, Yang; Jia, Haiqiang; Liu, Wuming; Chen, Hong

2014-01-01

The asymmetric dual-wavelength (green/blue) coupled InGaN/GaN multiple quantum wells were proposed to modulate the green emission intensity. Electroluminescent measurements demonstrate the conspicuous increment of the green light intensity by decreasing the coupled barrier thickness. This was partly attributed to capture of more carriers when holes tunnel across the thinner barrier from the blue quantum wells, as a hole reservoir, to the green quantum wells. While lower effective barrier height of the blue quantum wells benefits improved hole transportation from p-GaN to the active region. Efficiency droop of the green quantum wells was partially alleviated due to the enhanced injection efficiency of holes

Whole-Body High-Intensity Interval Training Induce Similar Cardiorespiratory Adaptations Compared With Traditional High-Intensity Interval Training and Moderate-Intensity Continuous Training in Healthy Men.

Science.gov (United States)

Schaun, Gustavo Z; Pinto, Stephanie S; Silva, Mariana R; Dolinski, Davi B; Alberton, Cristine L

2018-05-07

Schaun, GZ, Pinto, SS, Silva, MR, Dolinski, DB, and Alberton, CL. Sixteen weeks of whole-body high-intensity interval training induce similar cardiorespiratory responses compared with traditional high-intensity interval training and moderate-intensity continuous training in healthy men. J Strength Cond Res XX(X): 000-000, 2018-Low-volume high-intensity interval training (HIIT) protocols that use the body weight as resistance could be an interesting and inexpensive alternative to traditional ergometer-based high-intensity interval training (HIIT-T) and moderate-intensity continuous training (MICT). Therefore, our aim was to compare the effects of 16 weeks of whole-body HIIT (HIIT-WB), HIIT-T, and MICT on maximal oxygen uptake (V[Combining Dot Above]O2max), second ventilatory threshold (VT2), and running economy (RE) outcomes. Fifty-five healthy men (23.7 ± 0.7 years, 1.79 ± 0.01 m, 78.5 ± 1.7 kg) were randomized into 3 training groups (HIIT-T = 17; HIIT-WB = 19; MICT = 19) for 16 weeks (3× per week). The HIIT-T group performed eight 20-second bouts at 130% of the velocity associated to V[Combining Dot Above]O2max (vV[Combining Dot Above]O2max) interspersed by 10-second passive recovery on a treadmill, whereas HIIT-WB group performed the same protocol but used calisthenics exercises at an all-out intensity instead of treadmill running. Finally, MICT group exercised for 30 minutes at 90-95% of the heart rate (HR) associated to VT2. After the intervention, all groups improved V[Combining Dot Above]O2max, vV[Combining Dot Above]O2max, time to exhaustion (Tmax), VT2, velocity associated with VT2 (vVT2), and time to reach VT2 (tVT2) significantly (p HIIT-T compared with HIIT-WB (p HIIT-WB can be as effective as traditional HIIT while also being time-efficient compared with MICT to improve health-related outcomes after 16 weeks of training. However, HIIT-T and MICT seem preferable to enhance performance-related outcomes compared with HIIT-WB.

Flight control and landing precision in the nocturnal bee Megalopta is robust to large changes in light intensity

OpenAIRE

Baird, Emily; Fernandez, Diana C.; Wcislo, William T.; Warrant, Eric J.

2015-01-01

Like their diurnal relatives, Megalopta genalis use visual information to control flight. Unlike their diurnal relatives, however, they do this at extremely low light intensities. Although Megalopta has developed optical specializations to increase visual sensitivity, theoretical studies suggest that this enhanced sensitivity does not enable them to capture enough light to use visual information to reliably control flight in the rainforest at night. It has been proposed that Megalopta gain ex...

Low light intensity effects on the growth, photosynthetic characteristics, antioxidant capacity, yield and quality of wheat (Triticum aestivum L.) at different growth stages in BLSS

Science.gov (United States)

Dong, Chen; Fu, Yuming; Liu, Guanghui; Liu, Hong

2014-06-01

Minimizing energy consumption and maximizing crop productivity are major challenges to growing plants in Bioregenerative Life Support System (BLSS) for future long-term space mission. As a primary source of energy, light is one of the most important environmental factors for plant growth. The purpose of this study is to investigate the effects of low light intensity at different stages on growth, pigment composition, photosynthetic efficiency, biological production and antioxidant defence systems of wheat (Triticum aestivum L.) cultivars during ontogenesis. Experiments were divided into 3 intensity-controlled stages according to growth period (a total of 65 days): seedling stage (first 20 days), heading and flowering stage (middle 30 days) and grain filling stage (last 15 days). Initial light condition of the control was 420 μmol m-2 s-1 and the light intensity increased with the growth of wheat plants. The light intensities of group I and II at the first stage and the last stage were adjusted to the half level of the control respectively. For group III, the first and the last stage were both adjusted to half level of the control. During the middle 30 days, all treatments were kept the same intensity. The results indicated that low-light treatment at seedling stage, biomass, nutritional contents, components of inedible biomass and healthy index (including peroxidase (POD) activity, malondialdehyde (MDA) and proline content) of wheat plants have no significant difference to the control. Furthermore, unit kilojoule yield of group I reached 0.591 × 10-3 g/kJ and induced the highest energy efficiency. However, low-light treatment at grain filling stage affected the final production significantly.

Early High-Intensity Versus Low-Intensity Rehabilitation After Total Knee Arthroplasty (TKA) by Bade et al

DEFF Research Database (Denmark)

Mechlenburg, Inger; Skoffer, Birgit; Dalgas, Ulrik

2017-01-01

Recently, a paper entitled "Early High-Intensity Versus Low-Intensity Rehabilitation After Total Knee Arthroplasty: A Randomized Controlled Trial" was published in Arthritis Care Res by Bade et al. (1). We have read the paper with great interest and noted that the study shows essentially no diffe......Recently, a paper entitled "Early High-Intensity Versus Low-Intensity Rehabilitation After Total Knee Arthroplasty: A Randomized Controlled Trial" was published in Arthritis Care Res by Bade et al. (1). We have read the paper with great interest and noted that the study shows essentially...

Polyphenolic composition and antioxidant capacity of legume based swards are affected by light intensity in a Mediterranean agroforestry system.

Science.gov (United States)

Re, Giovanni Antonio; Piluzza, Giovanna; Sanna, Federico; Molinu, Maria Giovanna; Sulas, Leonardo

2018-06-01

In Mediterranean grazed woodlands, microclimate changes induced by trees influence the growth and development of the understory, but very little is known about its polyphenolic composition in relation to light intensity. We investigated the bioactive compounds and antioxidant capacity of different legume-based swards and variations due to full sunlight and partial shade. The research was carried out in a cork oak agrosilvopastoral system in Sardinia. The highest values of DPPH reached 7 mmol TEAC 100 g -1 DW, total phenolics 67.1 g GAE kg -1 DW and total flavonoids 7.5 g CE kg -1 DW. Compared to full sunlight, partial shade reduced DPPH values by 29 and 42%, and the total phenolic content by 23 and 53% in 100% legume mixture and semi natural pasture. Twelve phenolic compounds were detected: chlorogenic acid in 80% legume mixture (partial shade) and verbascoside in pure sward of bladder clover (full sunlight) were the most abundant. Light intensity significantly affected antioxidant capacity, composition and levels of phenolic compounds. Our results provide new insights into the effects of light intensity on plant secondary metabolites from legume based swards, underlining the important functions provided by agroforestry systems. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Comparison of in situ ionizing radiation effects on Raman and photoluminescence intensity of high OH, low OH silica, and fluoride core fibers

Science.gov (United States)

Bilodeau, T. G.; Ewing, K. J.; Nau, G. M.; Aggarwal, I. D.

1995-06-01

An in situ study of the effects of ionizing radiation on the strength of the Raman and photoluminescence signal of high OH, low OH, and fluoride core fibers has been performed with 514.5 nm laser excitation. The fibers were irradiated with a 60Co source at a constant dose rate of 560 rads/h. The high OH fiber displayed a much slower decay of the fiber Raman intensity than the other two fibers during irradiation. The fluoride fiber exhibited the quickest decline in Raman signal with the intensity dropping by a factor of 1000 in less than 20 min. The Raman intensity of the low OH silica fiber recovered to greater than 90% of its pre-irradiation value after a post-irradiation photoanneal with 488 nm laser light. The silica fibers displayed an increase in intensity of a broad photoluminescence feature centered at 650 nm. However the fiber photoluminescence intensity remained much weaker than the Raman intensity throughout the irradiations.

Subcarrier intensity modulation for MIMO visible light communications

Science.gov (United States)

Celik, Yasin; Akan, Aydin

2018-04-01

In this paper, subcarrier intensity modulation (SIM) is investigated for multiple-input multiple-output (MIMO) visible light communication (VLC) systems. A new modulation scheme called DC-aid SIM (DCA-SIM) is proposed for the spatial modulation (SM) transmission plan. Then, DCA-SIM is extended for multiple subcarrier case which is called DC-aid Multiple Subcarrier Modulation (DCA-MSM). Bit error rate (BER) performances of the considered system are analyzed for different MIMO schemes. The power efficiencies of DCA-SIM and DCA-MSM are shown in correlated MIMO VLC channels. The upper bound BER performances of the proposed models are obtained analytically for PSK and QAM modulation types in order to validate the simulation results. Additionally, the effect of power imbalance method on the performance of SIM is studied and remarkable power gains are obtained compared to the non-power imbalanced cases. In this work, Pulse amplitude modulation (PAM) and MSM-Index are used as benchmarks for single carrier and multiple carrier cases, respectively. And the results show that the proposed schemes outperform PAM and MSM-Index for considered single carrier and multiple carrier communication scenarios.

Adhesion characteristics of VO2 ink film sintered by intense pulsed light for smart window

Science.gov (United States)

Youn, Ji Won; Lee, Seok-Jae; Kim, Kwang-Seok; Kim, Dae Up

2018-05-01

Progress in the development of energy-efficient coatings on glass has led to the research of smart windows that can modulate solar energy in response to an external stimulus like light, heat, or electricity. Thermochromic smart windows have attracted great interest because they provide highly visible transparency and intelligently controllable solar heat. VO2 has been widely used as coating material for thermochromism owing to its reversible metal-to-insulator transition near room temperature. However, unstable crystalline phases and expensive fabrication processes of VO2 films limit their facile application in smart windows. To overcome these restrictions, we manufactured nanoinks based on VO2 nanoparticles and fabricated films using spin coating and intense pulsed light (IPL) sintering on a quartz substrate. We examined adhesion between the VO2 nanoink films and the quartz substrate by varying the applied voltages and the number of pulses. The average adhesion of thin films increased to 83 and 108 N/m as the applied voltage during IPL sintering increased from 1400 to 2000 V. By increasing the number of pulses from 5 to 20, the adhesive strength increased from 83 to 94 N/m at 1400 V, and decreased from 108 to 96 N/m at 2000 V voltage.

Intense pulsed light for photo-rejuvenation and freckles of middle eastern skin

International Nuclear Information System (INIS)

El Bedewi, A.F.

2003-01-01

Facial ageing is a gradual process which could be due to intrinsic and extrinsic causes and it ultimately results in the appearance of activity induced tissue ptosis, wrinkles, epidermal and dermal artoply, dryness, senile lentigo, flushing, telangiectasia and enlarged pores. Moreover, freckles are frequently seen on the face and other sun exposed areas and it is characterized with incrreased melanin in the epidermis. Intense Pulsed Light (IPL)is the latest technology for selective photo-thermolysis as a non-ablative photo-rejuvenation. Thirty-four patients of age ranging between 35- 70 years with skin type ranging between III-V with or without freckles were treated with 3-5 sessions of IPL. Three weeks intervals were considered between every two succesive session. Irradiation wavelength was controlled using cutoff filters ranging from 535 to 580 nmwith a fluence of 25-35 j/cm-2. Significant improvement was demonstrated after 6 months by computerized image analysis compared with the baseline. IPL was found to be effective and saf treatment for fine wrinkles, facial freckles, telangiectasia, flushing as well as post-inflammatory hyper-pigmentation with a high satisfactory level and a relatively afew adverse effects

Stimulated Raman backscattering at high laser intensities

Energy Technology Data Exchange (ETDEWEB)

Skoric, M M [Vinca Inst. of Nuclear Sciences, Belgrade (Yugoslavia); Tajima, Toshiki; Sasaki, Akira; Maluckov, A; Jovanovic, M

1998-03-01

Signatures of Stimulated Raman backscattering of a short-pulse high-intensity laser interacting with an underdense plasma are discussed. We introduce a nonlinear three-wave interaction model that accounts for laser pump depletion and relativistic detuning. A mechanism is revealed based on a generic route to chaos, that predicts a progressive increase of the backscatter complexity with a growing laser intensity. Importance of kinetic effects is outlined and demonstrated in fluid-hybrid and particle simulations. As an application, we show that spectral anomalies of the backscatter, predicted by the above model, are consistent with recent sub-picosecond, high-intensity laser gas-target measurements at Livermore and elsewhere. Finally, a recently proposed scheme for generation of ultra-short, low-prepulse laser pulses by Raman backscattering in a thin foil target, is shown. (author)

Metabolic Trade-offs between Biomass Synthesis and Photosynthate Export at Different Light Intensities in a Genome–Scale Metabolic Model of Rice

Directory of Open Access Journals (Sweden)

Mark Graham Poolman

2014-11-01

Full Text Available Previously we have used a genome scale model of rice metabolism to describe how metabolism reconfigures at different light intensities in an expanding leaf of rice. Although this established that the metabolism of the leaf was adequatelyrepresented, in the model, the scenario was not that of the typical function of the leaf --- to provide material for the rest of the plant. Here we extend our analysis to explore the transition to a source leaf as export of photosynthate increases at the expense of making leaf biomass precursors, again as a function of light intensity. In particular we investigate whether, when the leaf is making a smaller range of compounds for export to the phloem, the same changes occur in the interactions between mitochondrial and chloroplast metabolism as seen in biomass synthesis for growth when light intensity increases. Our results show that the same changes occur qualitatively, though there are slight quantitative differences reflecting differences in the energy and redox requirements for the different metabolic outputs.

Responses of crayfish photoreceptor cells following intense light adaptation.

Science.gov (United States)

Cummins, D R; Goldsmith, T H

1986-01-01

After intense orange adapting exposures that convert 80% of the rhodopsin in the eye to metarhodopsin, rhabdoms become covered with accessory pigment and appear to lose some microvillar order. Only after a delay of hours or even days is the metarhodopsin replaced by rhodopsin (Cronin and Goldsmith 1984). After 24 h of dark adaptation, when there has been little recovery of visual pigment, the photoreceptor cells have normal resting potentials and input resistances, and the reversal potential of the light response is 10-15 mV (inside positive), unchanged from controls. The log V vs log I curve is shifted about 0.6 log units to the right on the energy axis, quantitatively consistent with the decrease in the probability of quantum catch expected from the lowered concentration of rhodopsin in the rhabdoms. Furthermore, at 24 h the photoreceptors exhibit a broader spectral sensitivity than controls, which is also expected from accumulations of metarhodopsin in the rhabdoms. In three other respects, however, the transduction process appears to be light adapted: The voltage responses are more phasic than those of control photoreceptors. The relatively larger effect (compared to controls) of low extracellular Ca++ (1 mmol/l EGTA) in potentiating the photoresponses suggests that the photoreceptors may have elevated levels of free cytoplasmic Ca++. The saturating depolarization is only about 30% as large as the maximal receptor potentials of contralateral, dark controls, and by that measure the log V-log I curve is shifted downward by 0.54 log units.(ABSTRACT TRUNCATED AT 250 WORDS)

The Relationship between Thermal Comfort and Light Intensity with Sleep Quality and Eye Tiredness in Shift Work Nurses

OpenAIRE

Azmoon, Hiva; Dehghan, Habibollah; Akbari, Jafar; Souri, Shiva

2013-01-01

Environmental conditions such as lighting and thermal comfort are influencing factors on sleep quality and visual tiredness. The purpose of this study was the determination of the relationship between thermal comfort and light intensity with the sleep quality and eye fatigue in shift nurses. Method. This cross-sectional research was conducted on 82 shift-work personnel of 18 nursing workstations in Isfahan Al-Zahra Hospital, Iran, in 2012. Heat stress monitoring (WBGT) and photometer (Hagner ...

Scalable Light Module for Low-Cost, High-Efficiency Light- Emitting Diode Luminaires

Energy Technology Data Exchange (ETDEWEB)

Tarsa, Eric [Cree, Inc., Goleta, CA (United States)

2015-08-31

During this two-year program Cree developed a scalable, modular optical architecture for low-cost, high-efficacy light emitting diode (LED) luminaires. Stated simply, the goal of this architecture was to efficiently and cost-effectively convey light from LEDs (point sources) to broad luminaire surfaces (area sources). By simultaneously developing warm-white LED components and low-cost, scalable optical elements, a high system optical efficiency resulted. To meet program goals, Cree evaluated novel approaches to improve LED component efficacy at high color quality while not sacrificing LED optical efficiency relative to conventional packages. Meanwhile, efficiently coupling light from LEDs into modular optical elements, followed by optimally distributing and extracting this light, were challenges that were addressed via novel optical design coupled with frequent experimental evaluations. Minimizing luminaire bill of materials and assembly costs were two guiding principles for all design work, in the effort to achieve luminaires with significantly lower normalized cost ($/klm) than existing LED fixtures. Chief project accomplishments included the achievement of >150 lm/W warm-white LEDs having primary optics compatible with low-cost modular optical elements. In addition, a prototype Light Module optical efficiency of over 90% was measured, demonstrating the potential of this scalable architecture for ultra-high-efficacy LED luminaires. Since the project ended, Cree has continued to evaluate optical element fabrication and assembly methods in an effort to rapidly transfer this scalable, cost-effective technology to Cree production development groups. The Light Module concept is likely to make a strong contribution to the development of new cost-effective, high-efficacy luminaries, thereby accelerating widespread adoption of energy-saving SSL in the U.S.

Do light cured ART conventional high-viscosity glass-ionomer sealants perform better than resin-composite sealants: a 4-year randomized clinical trial

NARCIS (Netherlands)

Zhang, W.; Chen, X.; Fan, M.W.; Mulder, J.; Huysmans, M.C.D.N.J.M.; Frencken, J.E.F.M.

2014-01-01

OBJECTIVE: The hypotheses tested were: the cumulative survival rates of dentin caries lesion-free pits and fissures of ART conventional high-viscosity glass-ionomer sealants with light-curing (high-intensity LED) and glass-carbomer sealants are higher than those of conventional ART sealants and

Geolocation by light

DEFF Research Database (Denmark)

Lisovski, Simeon; Hewson, Chris M.; Klaassen, Raymond H. G.

2012-01-01

1. Geolocation by light allows for tracking animal movements, based on measurements of light intensity over time by a data-logging device (‘geolocator’). Recent developments of ultra-light devices (.... However, an inherent problem of geolocators is that any factor or process that changes the natural light intensity pattern also affects the positions calculated from these light patterns. Although the most important factors have been identified, estimation of their effect on the accuracy and precision...... of positions estimated has been lacking but is very important for the analyses and interpretation of geolocator data. 2. The ‘threshold method’ is mainly used to derive positions by defining sunrise and sunset times from the light intensity pattern for each recorded day. This method requires calibration...

[Reparative Osteogenesis and Angiogenesis in Low Intensity Electromagnetic Radiation of Ultra-High Frequency].

Science.gov (United States)

Iryanov, Y M; Kiryanov, N A

2015-01-01

Non-drug correction of reparative bone tissue regeneration in different pathological states - one of the most actual problems of modern medicine. Our aim was to conduct morphological analysis of the influence of electromagnetic radiation of ultra-high frequency and low intensity on reparative osteogenesis and angiogenesis in fracture treatment under transosseous osteosynthesis. A controlled nonrandomized study was carried out. In the experiment conducted on rats we modeled tibial fracture with reposition and fixation of the bone fragments both in control and experimental groups. In the animals of the experimental group the fracture zone was exposed to low intensity electromagnetic radiation of ultra-high frequency. Exposure simulation was performed in the control group. The operated bones were examined using radiography, light and electronic microscopy, X-ray electronic probe microanalysis. It has been established that electromagnetic radiation of ultra-high frequency sessions in fracture treatment stimulate secretory activity and degranulation of mast cells, produce microcirculatory bed vascular permeability increase, endotheliocyte migration phenotype expression, provide endovascular endothelial outgrowth formation, activate reparative osteogenesis and angiogenesis while fracture reparation becomes the one of the primary type. The full periosteal, intermediary and intraosteal bone union was defined in 28 days. Among the therapeutic benefits of electromagnetic radiation of ultra-high frequency in fracture treatment we can detect mast cell secretorv activity stimulation and endovascular anziozenesis activation.

Linear surface photoelectric effect of gold in intense laser field as a possible high-current electron source

International Nuclear Information System (INIS)

Farkas, G.; Horvath, Z.G.; Toth, C.; Fotakis, C.; Hontzopoulos, E.

1987-01-01

Investigations were conducted on radiation-induced electron emission processes on a gold target surface with a high-intensity (2 MW/cm 2 ) KrF laser (λ = 248 nm). The single photon surface photoelectric emission obtained can be used for high-current density electron sources. The measured polarization dependence of electron current shows the dominance of the surface-type effect over that of the volume type, thereby making it possible to optimize the short, high-density electron current creation conditions. The advantage of the grazing light incidence and the multiphoton photoeffect giving rise to a 500 A/cm 2 electron current has been demonstrated

Pulsed system for obtaining microdosimetric data with high intensity beams

International Nuclear Information System (INIS)

Zaider, M.; Dicello, J.F.; Hiebert, R.D.

1977-01-01

The use of heavy particle accelerators for radiation therapy requires high intensity beams in order to produce useful dose rates. The 800-MeV proton beam at LAMPF passes through different production targets to generate secondary pion beams. Conventional microdosimetric techniques are not applicable under these conditions because exceedingly high count rates result in detector damage, gas breakdown, and saturation effects in the electronics. We describe a new microdosimetric system developed at the Pion Biomedical Channel of LAMPF. The accelerator provides a variable low intensity pulse once every ten high intensity macropulses. The voltage on the detector is pulsed in coincidence with the low intensity pulse so that we were able to operate the detector under optimum data-taking conditions. A low noise two-stage preamplifier was built in connection with the pulsed mode operation. A comparison is made between data obtained in pulsed (high intensity beam) and unpulsed (low intensity beam) modes. The spectra obtained by the two methods agree within the experimental uncertainties

The Relationship between Thermal Comfort and Light Intensity with Sleep Quality and Eye Tiredness in Shift Work Nurses

Science.gov (United States)

Azmoon, Hiva; Dehghan, Habibollah; Akbari, Jafar; Souri, Shiva

2013-01-01

Environmental conditions such as lighting and thermal comfort are influencing factors on sleep quality and visual tiredness. The purpose of this study was the determination of the relationship between thermal comfort and light intensity with the sleep quality and eye fatigue in shift nurses. Method. This cross-sectional research was conducted on 82 shift-work personnel of 18 nursing workstations in Isfahan Al-Zahra Hospital, Iran, in 2012. Heat stress monitoring (WBGT) and photometer (Hagner Model) were used for measuring the thermal conditions and illumination intensity, respectively. To measure the sleep quality, visual tiredness, and thermal comfort, Pittsburg sleep quality index, eye fatigue questionnaire, and thermal comfort questionnaire were used, respectively. The data were analyzed with descriptive statistics, Student's t-test, and Pearson correlation. Results. Correlation between thermal comfort which was perceived from the self-reporting of people with eye tiredness was −0.38 (P = 0.002). Pearson correlation between thermal comfort and sleep quality showed a positive and direct relationship (r = 0.241, P = 0.33) but the correlation between thermal comfort, which was perceived from the self-reporting of shift nurses, and WBGT index was a weak relationship (r = 0.019). Conclusion. Based on the obtained findings, it can be concluded that a defect in environmental conditions such as thermal conditions and light intensity and also lack of appropriate managerial plan for night shift-work nurses are destructive and negative factors for the physical and mental health of this group of practitioners. PMID:23476674

The relationship between thermal comfort and light intensity with sleep quality and eye tiredness in shift work nurses.

Science.gov (United States)

Azmoon, Hiva; Dehghan, Habibollah; Akbari, Jafar; Souri, Shiva

2013-01-01

Environmental conditions such as lighting and thermal comfort are influencing factors on sleep quality and visual tiredness. The purpose of this study was the determination of the relationship between thermal comfort and light intensity with the sleep quality and eye fatigue in shift nurses. This cross-sectional research was conducted on 82 shift-work personnel of 18 nursing workstations in Isfahan Al-Zahra Hospital, Iran, in 2012. Heat stress monitoring (WBGT) and photometer (Hagner Model) were used for measuring the thermal conditions and illumination intensity, respectively. To measure the sleep quality, visual tiredness, and thermal comfort, Pittsburg sleep quality index, eye fatigue questionnaire, and thermal comfort questionnaire were used, respectively. The data were analyzed with descriptive statistics, Student's t-test, and Pearson correlation. Correlation between thermal comfort which was perceived from the self-reporting of people with eye tiredness was -0.38 (P = 0.002). Pearson correlation between thermal comfort and sleep quality showed a positive and direct relationship (r = 0.241, P = 0.33) but the correlation between thermal comfort, which was perceived from the self-reporting of shift nurses, and WBGT index was a weak relationship (r = 0.019). Based on the obtained findings, it can be concluded that a defect in environmental conditions such as thermal conditions and light intensity and also lack of appropriate managerial plan for night shift-work nurses are destructive and negative factors for the physical and mental health of this group of practitioners.

Laser-matter interaction at high intensity and high temporal contrast

International Nuclear Information System (INIS)

Doumy, G.

2006-01-01

The continuous progress in the development of laser installations has already lead to ultra-short pulses capable of achieving very high focalized intensities (I > 10 18 W/cm 2 ). At these intensities, matter presents new non-linear behaviours, due to the fact that the electrons are accelerated to relativistic speeds. The experimental access to this interaction regime on solid targets has long been forbidden because of the presence, alongside the femtosecond pulse, of a pedestal (mainly due to the amplified spontaneous emission (ASE) which occurs in the laser chain) intense enough to modify the state of the target. In this thesis, we first characterized, both experimentally and theoretically, a device which allows an improvement of the temporal contrast of the pulse: the Plasma Mirror. It consists in adjusting the focusing of the pulse on a dielectric target, so that the pedestal is mainly transmitted, while the main pulse is reflected by the overcritical plasma that it forms at the surface. The implementation of such a device on the UHI 10 laser facility (CEA Saclay - 10 TW - 60 fs) then allowed us to study the interaction between ultra-intense, high contrast pulses with solid targets. In a first part, we managed to generate and characterize dense plasmas resulting directly from the interaction between the main pulse and very thin foils (100 nm). This characterization was realized by using an XUV source obtained by high order harmonics generation in a rare gas jet. In a second part, we studied experimentally the phenomenon of high order harmonics generation on solid targets, which is still badly understood, but could potentially lead to a new kind of energetic ultra-short XUV sources. (author)

Half-integer resonance crossing in high-intensity rings

Directory of Open Access Journals (Sweden)

A. V. Fedotov

2002-02-01

Full Text Available A detailed study of the influence of space charge on the crossing of second-order resonances is presented and associated with the space-charge limit of high-intensity rings. Two-dimensional simulation studies are compared with envelope models, which agree in the finding of an increased intensity limit due to the coherent frequency shift. This result is also found for realistic bunched beams with multiturn injection painting. Characteristic features such as the influence of tune splitting, structure resonances, and the role of envelope instabilities are discussed in detail. The theoretical limits are found to be in good agreement with the performance of high-intensity proton machines.

LHC Report: reaching high intensity

CERN Multimedia

Jan Uythoven

2015-01-01

After both beams having been ramped to their full energy of 6.5 TeV, the last two weeks saw the beam commissioning process advancing on many fronts. An important milestone was achieved when operators succeeded in circulating a nominal-intensity bunch. During the operation, some sudden beam losses resulted in beam dumps at top energy, a problem that needed to be understood and resolved.   In 2015 the LHC will be circulating around 2800 bunches in each beam and each bunch will contain just over 1 x 1011 protons. Until a few days ago commissioning was taking place with single bunches of 5 x 109 protons. The first nominal bunch with an intensity of 1 x 1011 protons was injected on Tuesday, 21 April. In order to circulate such a high-intensity bunch safely, the whole protection system must be working correctly: collimators, which protect the aperture, are set at preliminary values known as coarse settings; all kicker magnets for injecting and extracting the beams are commissioned with beam an...

Underutilization of high-intensity statin therapy after hospitalization for coronary heart disease.

Science.gov (United States)

Rosenson, Robert S; Kent, Shia T; Brown, Todd M; Farkouh, Michael E; Levitan, Emily B; Yun, Huifeng; Sharma, Pradeep; Safford, Monika M; Kilgore, Meredith; Muntner, Paul; Bittner, Vera

2015-01-27

National guidelines recommend use of high-intensity statins after hospitalization for coronary heart disease (CHD) events. This study sought to estimate the proportion of Medicare beneficiaries filling prescriptions for high-intensity statins after hospital discharge for a CHD event and to analyze whether statin intensity before hospitalization is associated with statin intensity after discharge. We conducted a retrospective cohort study using a 5% random sample of Medicare beneficiaries between 65 and 74 years old. Beneficiaries were included in the analysis if they filled a statin prescription after a CHD event (myocardial infarction or coronary revascularization) in 2007, 2008, or 2009. High-intensity statins included atorvastatin 40 to 80 mg, rosuvastatin 20 to 40 mg, and simvastatin 80 mg. Among 8,762 Medicare beneficiaries filling a statin prescription after a CHD event, 27% of first post-discharge fills were for a high-intensity statin. The percent filling a high-intensity statin post-discharge was 23.1%, 9.4%, and 80.7%, for beneficiaries not taking statins pre-hospitalization, taking low/moderate-intensity statins, and taking high-intensity statins before their CHD event, respectively. Compared with beneficiaries not on statin therapy pre-hospitalization, multivariable adjusted risk ratios for filling a high-intensity statin were 4.01 (3.58-4.49) and 0.45 (0.40-0.52) for participants taking high-intensity and low/moderate-intensity statins before their CHD event, respectively. Only 11.5% of beneficiaries whose first post-discharge statin fill was for a low/moderate-intensity statin filled a high-intensity statin within 365 days of discharge. The majority of Medicare beneficiaries do not fill high-intensity statins after hospitalization for CHD. Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Integrated High Resolution Digital Color Light Sensor in 130 nm CMOS Technology

Directory of Open Access Journals (Sweden)

Drago Strle

2015-07-01

Full Text Available This article presents a color light detection system integrated in 130 nm CMOS technology. The sensors and corresponding electronics detect light in a CIE XYZ color luminosity space using on-chip integrated sensors without any additional process steps, high-resolution analog-to-digital converter, and dedicated DSP algorithm. The sensor consists of a set of laterally arranged integrated photodiodes that are partly covered by metal, where color separation between the photodiodes is achieved by lateral carrier diffusion together with wavelength-dependent absorption. A high resolution, hybrid, ∑∆ ADC converts each photo diode’s current into a 22-bit digital result, canceling the dark current of the photo diodes. The digital results are further processed by the DSP, which calculates normalized XYZ or RGB color and intensity parameters using linear transformations of the three photo diode responses by multiplication of the data with a transformation matrix, where the coefficients are extracted by training in combination with a pseudo-inverse operation and the least-mean square approximation. The sensor system detects the color light parameters with 22-bit accuracy, consumes less than 60 μA on average at 10 readings per second, and occupies approx. 0.8 mm2 of silicon area (including three photodiodes and the analog part of the ADC. The DSP is currently implemented on FPGA.

Integrated High Resolution Digital Color Light Sensor in 130 nm CMOS Technology.

Science.gov (United States)

Strle, Drago; Nahtigal, Uroš; Batistell, Graciele; Zhang, Vincent Chi; Ofner, Erwin; Fant, Andrea; Sturm, Johannes

2015-07-22

This article presents a color light detection system integrated in 130 nm CMOS technology. The sensors and corresponding electronics detect light in a CIE XYZ color luminosity space using on-chip integrated sensors without any additional process steps, high-resolution analog-to-digital converter, and dedicated DSP algorithm. The sensor consists of a set of laterally arranged integrated photodiodes that are partly covered by metal, where color separation between the photodiodes is achieved by lateral carrier diffusion together with wavelength-dependent absorption. A high resolution, hybrid, ∑∆ ADC converts each photo diode's current into a 22-bit digital result, canceling the dark current of the photo diodes. The digital results are further processed by the DSP, which calculates normalized XYZ or RGB color and intensity parameters using linear transformations of the three photo diode responses by multiplication of the data with a transformation matrix, where the coefficients are extracted by training in combination with a pseudo-inverse operation and the least-mean square approximation. The sensor system detects the color light parameters with 22-bit accuracy, consumes less than 60 μA on average at 10 readings per second, and occupies approx. 0.8 mm(2) of silicon area (including three photodiodes and the analog part of the ADC). The DSP is currently implemented on FPGA.

Light intensity and production parameters of phytocenoses cultivated on soil-like substrate under controled environment conditions

Science.gov (United States)

Tikhomirov, A.; Ushakova, S.; Gribovskaya, I.; Tirranen, L.; Manukovsky, N.; Zolotukhin, I.

To investigate feasibility of enhancing closedness in a new generation of biological life support systems (LSS) to involve the inedible phytomass into intrasystem mass exchange the vermicomposting method we have chosen made possible to produce soil-like substrate (SLS) suitable for growing plants. However, to use the SLS in life support systems call for investigation of its physical, chemical and other parameters. Of special importance among them is the capacity of SLS to provide the LSS photosynthesizing component with required mineral elements in selected cultivation conditions. In this connection the aim of this work was to study opportunities of enhancing pr4oduction activity of wheat and radish cenoses by varying the intensity of photosynthetically active radiation (PAR) without decreasing the harvest index. Increase of light intensity to 250 W/m 2 PAR decreased the intensity of visible photosynthesis of wheat cenosi and slightly increased visible photosynthesis of radish cenosis as compared to 200 W/m 2 PAR. The maximum productivity of wheat cenosis both total and seeds corresponded to the irradiance of 200 W/m 2 PAR. The light intensity of 250 W/m2 PAR decreased productivity of wheat plants and had no significant effect of the productivity of radish cenosis as compared to 200 W/m 2 PAR. Qualitative and quantitative composition of microflora of the watering solution and SLS was determined by the condition of plants, development phase and PAR intensity. By the end of wheat vegetation under 250 W/m 2 there were an order more bacteria of the colon rod group and phytopathogenic bacteria in the watering solution and SLS than under other illumination conditions. Investigation of the mineral composition of SLS and the watering solution demonstrated that one of the reasons of inadequate response of the cenosis under study to elevated PAR intensity may be deficiency of accessible forms of some mineral elements, e.g. nitrogen. The above said materials evidence that

Transmission Lines or Poles, Electric, MDTA High Mast lighting, High Mast Lighting along I 95, Maryland Transportation Authority High Mast Lighting poles, Published in 2011, 1:1200 (1in=100ft) scale, Maryland Transportation Authority.

Data.gov (United States)

NSGIC State | GIS Inventory — Transmission Lines or Poles, Electric dataset current as of 2011. MDTA High Mast lighting, High Mast Lighting along I 95, Maryland Transportation Authority High Mast...

Light-emitting diode lighting for forest nursery seedling production

Science.gov (United States)

R. Kasten Dumroese; Jeremiah R. Pinto; Anthony S. Davis

2015-01-01

Crop lighting is an energy-intensive necessity for nursery production of high-quality native plants and forest tree seedlings. During the winter months (especially in northern USA latitudes) or overcast or cloudy days, the amount of solar radiation reaching greenhouse crops is insufficient resulting in growth cessation, early terminal bud formation, and failure of...

Cryogenic semiconductor high-intensity radiation monitors

International Nuclear Information System (INIS)

Palmieri, V.G.; Bell, W.H.; Borer, K.; Casagrande, L.; Da Via, C.; Devine, S.R.H.; Dezillie, B.; Esposito, A.; Granata, V.; Hauler, F.; Jungermann, L.; Li, Z.; Lourenco, C.; Niinikoski, T.O.; Shea, V. O'; Ruggiero, G.; Sonderegger, P.

2003-01-01

This paper describes a novel technique to monitor high-intensity particle beams by means of a semiconductor detector. It consists of cooling a semiconductor detector down to cryogenic temperature to suppress the thermally generated leakage current and to precisely measure the integrated ionization signal. It will be shown that such a device provides very good linearity and a dynamic range wider than is possible with existing techniques. Moreover, thanks to the Lazarus effect, extreme radiation hardness can be achieved providing in turn absolute intensity measurements against precise calibration of the device at low beam flux

Effects of water stress and light intensity on chlorophyll fluorescence parameters and pigments of Aloe vera L.

Science.gov (United States)

Hazrati, Saeid; Tahmasebi-Sarvestani, Zeinolabedin; Modarres-Sanavy, Seyed Ali Mohammad; Mokhtassi-Bidgoli, Ali; Nicola, Silvana

2016-09-01

Aloe vera L. is one of the most important medicinal plants in the world. In order to determine the effects of light intensity and water deficit stress on chlorophyll (Chl) fluorescence and pigments of A. vera, a split-plot in time experiment was laid out in a randomized complete block design with four replications in a research greenhouse. The factorial combination of three light intensities (50, 75 and 100% of sunlight) and four irrigation regimes (irrigation after depleting 20, 40, 60 and 80% of soil water content) were considered as main factors. Sampling time was considered as sub factor. The first, second and third samplings were performed 90, 180 and 270 days after imposing the treatments, respectively. The results demonstrated that the highest light intensity and the severe water stress decreased maximum fluorescence (Fm), variable fluorescence (Fv)/Fm, quantum yield of PSII photochemistry (ФPSII), Chl and photochemical quenching (qP) but increased non-photochemical quenching (NPQ), minimum fluorescence (F0) and Anthocyanin (Anth). Additionally, the highest Fm, Fv/Fm, ФPSII and qP and the lowest NPQ and F0 were observed when 50% of sunlight was blocked and irrigation was done after 40% soil water depletion. Irradiance of full sunlight and water deficit stress let to the photoinhibition of photosynthesis, as indicated by a reduced quantum yield of PSII, ФPSII, and qP, as well as higher NPQ. Thus, chlorophyll florescence measurements provide valuable physiological data. Close to half of total solar radiation and irrigation after depleting 40% of soil water content were selected as the most efficient treatments. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Analysis of technology and seminar on economic trends about High-intensity LED

International Nuclear Information System (INIS)

2003-09-01

This is divided into two parts. Contents of this report in the first part are technical trends on high-intensity LED which reports introduction of LED as compound semiconductor, white LED? patent issues, review on technology of High-intensity LED and Reliability of High-intensity LED. The second part deals with economic tends about High-intensity LED. This seminar was held to report analysis and economical trends about High-intensity LED by Korea Industrial Education Institute in 2003.

Photoluminescence and reflectivity studies of high energy light ions irradiated polymethyl methacrylate films

Science.gov (United States)

Bharti, Madhu Lata; Singh, Fouran; Ramola, R. C.; Joshi, Veena

2017-11-01

The self-standing films of non-conducting polymethyl methacrylate (PMMA) were irradiated in vacuum using high energy light ions (HELIs) of 50 MeV Lithium (Li+3) and 80 MeV Carbon (C+5) at various ion dose to induce the optical changes in the films. Upon HELI irradiation, films exhibit a significant enhancement in optical reflectivity at the highest dose. Interestingly, the photoluminescence (PL) emission band with green light at (514.5 nm) shows a noticeable increase in the intensity with increasing ion dose for both ions. However, the rate of increase in PL intensity is different for both HELI and can be correlated with the linear energy transfer by these ions in the films. Origin of PL is attributed to the formation of carbon cluster and hydrogenated amorphous carbon in the polymer films. HAC clusters act as PL active centres with optical reflectivity. Most of the harmful radiation like UV are absorbed by the material and is becoming opaque after irradiation and this PL active material are useful in fabrication of optoelectronic devices, UV-filter, back-lit components in liquid crystal display systems, micro-components for integrate optical circuits, diffractive elements, advanced materials and are also applicable to the post irradiation laser treatment by means of ion irradiation.